Investigation of the effects of selected bio-based carburising agents on mechanical and microstructural characteristics of gray cast iron
- Salawu, Enesi Y, Akinlabi, Esther, Inegbenebo, Anthony O, Ajayi, Oluseyi O, Akinlabi, Stephen, Popoola, A P I, Uyo, U O
- Authors: Salawu, Enesi Y , Akinlabi, Esther , Inegbenebo, Anthony O , Ajayi, Oluseyi O , Akinlabi, Stephen , Popoola, A P I , Uyo, U O
- Date: 2020
- Language: English
- Type: Journal Article
- Identifier: http://hdl.handle.net/11260/4735 , vital:44172
- Full Text:
- Authors: Salawu, Enesi Y , Akinlabi, Esther , Inegbenebo, Anthony O , Ajayi, Oluseyi O , Akinlabi, Stephen , Popoola, A P I , Uyo, U O
- Date: 2020
- Language: English
- Type: Journal Article
- Identifier: http://hdl.handle.net/11260/4735 , vital:44172
- Full Text:
JEOR Fagara Reprints.pdf
- Authors: Oyedeji, Adebola Omowunmi
- Language: English
- Identifier: http://hdl.handle.net/11260/2492 , vital:41892
- Description: Various articles from Prof Adebola Oyedeji
- Full Text:
- Authors: Oyedeji, Adebola Omowunmi
- Language: English
- Identifier: http://hdl.handle.net/11260/2492 , vital:41892
- Description: Various articles from Prof Adebola Oyedeji
- Full Text:
Knowledge Policing: Re-conceptualizing Ogun in Peter Omoko’s Battles of Pleasure and Roy-Omoni’s Morontonu
- Olutoba Gboyega Oluwasuji,, Sone Mirabeau Enongene
- Authors: Olutoba Gboyega Oluwasuji, , Sone Mirabeau Enongene
- Date: 2021
- Subjects: Coloniality, Decolonial Epistemic Perspective, Knowledge Policing, Ogun, Yoruba
- Language: English
- Type: Journal Article
- Identifier: http://hdl.handle.net/11260/2688 , vital:42323
- Full Text:
- Authors: Olutoba Gboyega Oluwasuji, , Sone Mirabeau Enongene
- Date: 2021
- Subjects: Coloniality, Decolonial Epistemic Perspective, Knowledge Policing, Ogun, Yoruba
- Language: English
- Type: Journal Article
- Identifier: http://hdl.handle.net/11260/2688 , vital:42323
- Full Text:
Kuria and Oyedeji.pdf
- Authors: Oyedeji, Adebola Omowunmi
- Language: English
- Identifier: http://hdl.handle.net/11260/2446 , vital:41911
- Description: Various articles from Prof Adebola Oyedeji
- Full Text:
- Authors: Oyedeji, Adebola Omowunmi
- Language: English
- Identifier: http://hdl.handle.net/11260/2446 , vital:41911
- Description: Various articles from Prof Adebola Oyedeji
- Full Text:
Language And Gender Interaction In Bakossi Proverbial Discourse
- Authors: Enongene Mirabeau Sone
- Date: 2016
- Subjects: Language use, gender, sexist, sexism, Bakossi, proverbs, discourse
- Language: English
- Type: Journal Article
- Identifier: http://hdl.handle.net/11260/2616 , vital:42294
- Description: Language can be seen as a systematic means which human beings use in the communication of thoughts, ideas, values, norms and feelings. As a pervasive aspect of our lives, it is a verbal means with which we communicate and conduct social interaction. This paper examines specific aspects of proverbial language of the Bakossi people of the South West Region of Cameroon and determines through a feminist analysis how this language use illustrates in-built sexist connotation in the sense that it generally indicates positive things for males while negative connotations are assumed for women. Proverbs, pronominal forms and idiomatic expressions are collected and analysed to ascertain the above argument. The evidence in this paper serves as a reference point for women of sexism that is built into language use in these old pithy sayings which are meant to encapsulate pearls of wisdom
- Full Text:
- Authors: Enongene Mirabeau Sone
- Date: 2016
- Subjects: Language use, gender, sexist, sexism, Bakossi, proverbs, discourse
- Language: English
- Type: Journal Article
- Identifier: http://hdl.handle.net/11260/2616 , vital:42294
- Description: Language can be seen as a systematic means which human beings use in the communication of thoughts, ideas, values, norms and feelings. As a pervasive aspect of our lives, it is a verbal means with which we communicate and conduct social interaction. This paper examines specific aspects of proverbial language of the Bakossi people of the South West Region of Cameroon and determines through a feminist analysis how this language use illustrates in-built sexist connotation in the sense that it generally indicates positive things for males while negative connotations are assumed for women. Proverbs, pronominal forms and idiomatic expressions are collected and analysed to ascertain the above argument. The evidence in this paper serves as a reference point for women of sexism that is built into language use in these old pithy sayings which are meant to encapsulate pearls of wisdom
- Full Text:
Late diagnosis of human immunodeficiency virus infection is linked to higher rates of epilepsy in children in the Eastern Cape of South Africa
- Isabel A. Michaelis, Craig Carty, Maryke Nielsen, Markus Wolff, Caroline A. Sabin, John S. Lambert
- Authors: Isabel A. Michaelis , Craig Carty , Maryke Nielsen , Markus Wolff , Caroline A. Sabin , John S. Lambert
- Date: 2020
- Language: English
- Type: Journal Article
- Identifier: http://hdl.handle.net/11260/4237 , vital:44050
- Full Text:
- Authors: Isabel A. Michaelis , Craig Carty , Maryke Nielsen , Markus Wolff , Caroline A. Sabin , John S. Lambert
- Date: 2020
- Language: English
- Type: Journal Article
- Identifier: http://hdl.handle.net/11260/4237 , vital:44050
- Full Text:
Learners' Attitudes Influencing their performance in the study of Mathematics in Seven Selected Senior Secondary Schools in the Mthatha Education District
- Authors: Gyeke, Yirenkyi - Darko
- Date: 2015
- Subjects: Mathematics Education
- Language: English
- Type: Thesis, D Ed
- Identifier: http://hdl.handle.net/11260/2222 , vital:40919
- Full Text: false
- Authors: Gyeke, Yirenkyi - Darko
- Date: 2015
- Subjects: Mathematics Education
- Language: English
- Type: Thesis, D Ed
- Identifier: http://hdl.handle.net/11260/2222 , vital:40919
- Full Text: false
Leonotis paper.pdf
- Authors: Oyedeji, Adebola Omowunmi
- Language: English
- Identifier: http://hdl.handle.net/11260/2456 , vital:41898
- Description: Various articles from Prof Adebola Oyedeji
- Full Text:
- Authors: Oyedeji, Adebola Omowunmi
- Language: English
- Identifier: http://hdl.handle.net/11260/2456 , vital:41898
- Description: Various articles from Prof Adebola Oyedeji
- Full Text:
Leveraging polymerase chain reaction technique (GeneXpert) to upscaling testing capacity for SARSCoV- 2 (COVID-19) in Nigeria: a game changer
- Olanrewaju Oladimeji, Bamidele Paul Atiba, Daniel Adedayo Adeyinka
- Authors: Olanrewaju Oladimeji , Bamidele Paul Atiba , Daniel Adedayo Adeyinka
- Date: 2020
- Language: English
- Type: Journal Article
- Identifier: http://hdl.handle.net/11260/4184 , vital:44036
- Full Text:
- Authors: Olanrewaju Oladimeji , Bamidele Paul Atiba , Daniel Adedayo Adeyinka
- Date: 2020
- Language: English
- Type: Journal Article
- Identifier: http://hdl.handle.net/11260/4184 , vital:44036
- Full Text:
LIPOPROTEINS AND THEIR SUBFRACTIONS IN TYPE 2 DIABETES PATIENTS FROM MTHATHA, EASTERN CAPE, SOUTH AFRICA
- Authors: JIM JOSEPH THYTHARAYIL
- Date: 2017
- Subjects: Biochemistry
- Language: English
- Type: Thesis, Doctoral
- Identifier: http://hdl.handle.net/11260/2116 , vital:40897
- Description: Cardiovascular disease is the main cause of mortality in diabetic patients and the risk of mortality due to cardiovascular disease is 2-4 times higher in diabetic patients when compared to the general population. The dysregulation of lipid metabolism due to abnormal insulin concentration or activity is one of the major reasons for the increased cardiovascular risk associated with diabetes. The main objective of the study was to analyse the alterations in the sub-fractions of lipoproteins in type 2 diabetic patients from hospitals and clinics around Mthatha. The results of the study showed that the concentration of small dense low density lipoproteins (LDL) was highly elevated in the diabetic patients with diabetic patients having four times the odds of having a pattern of increased small dense LDL than people without diabetes. The diabetic patients also had a very high concentration of oxidized low-density lipoprotein and lipoprotein (a). These alterations in lipid concentration exposed the diabetic patients to high risk of cardiovascular disease. This atherogenic alteration in lipid concentration could not be detected by the traditional lipid profile and hence analysis of lipoprotein sub-fractions can help in better management and decrease cardiovascular events in diabetic patients.
- Full Text: false
- Authors: JIM JOSEPH THYTHARAYIL
- Date: 2017
- Subjects: Biochemistry
- Language: English
- Type: Thesis, Doctoral
- Identifier: http://hdl.handle.net/11260/2116 , vital:40897
- Description: Cardiovascular disease is the main cause of mortality in diabetic patients and the risk of mortality due to cardiovascular disease is 2-4 times higher in diabetic patients when compared to the general population. The dysregulation of lipid metabolism due to abnormal insulin concentration or activity is one of the major reasons for the increased cardiovascular risk associated with diabetes. The main objective of the study was to analyse the alterations in the sub-fractions of lipoproteins in type 2 diabetic patients from hospitals and clinics around Mthatha. The results of the study showed that the concentration of small dense low density lipoproteins (LDL) was highly elevated in the diabetic patients with diabetic patients having four times the odds of having a pattern of increased small dense LDL than people without diabetes. The diabetic patients also had a very high concentration of oxidized low-density lipoprotein and lipoprotein (a). These alterations in lipid concentration exposed the diabetic patients to high risk of cardiovascular disease. This atherogenic alteration in lipid concentration could not be detected by the traditional lipid profile and hence analysis of lipoprotein sub-fractions can help in better management and decrease cardiovascular events in diabetic patients.
- Full Text: false
Management of discipline policy for educators by school management teams in the Maluti district, Eastern Cape Province (RSA): a case study of two selected schools
- Authors: Lishman, Bilibane Thabo
- Date: 2014
- Subjects: Educational Management and Policy
- Language: English
- Type: Masters, Ed
- Identifier: http://hdl.handle.net/11260/2353 , vital:41450
- Description: This research project was an attempt to determine School Management Teams (SMTs) management of teacher discipline at school using the discipline policy (code of conduct for educators) as a frame of reference. This was because procedures and processes for managing teacher discipline were new to principals and their SMTs. The main aim was to investigate the practices and experiences of SMTs regarding management of discipline policy for better or improved teacher conduct. Again, the study sought to understand and explain the gap between discipline policy and its implementation as SMTs seemed to be grappling with the implementation process thereof. The study is located in an interpretive and qualitative perspective where a case study research design was used. Face-to-face interviews were used to collect data from participants selected from two schools (school A and school B). The participants were sampled purposively out of a population of 245 principals and 245 site stewards. The principal and site steward of each school were interviewed because they were found to be relevant to the case of discipline policy implementation. The principal of each school represented the SMT while the site stewards represented the teaching staff. There were therefore four participants who contributed to data collection. During the data collection process, all issues of ethics like voluntary participation, permission, informed consent, confidentiality, anonymity and rights of participants were considered. As data were collected using face-to-face interviews, they were analysed qualitatively, using interim analysis of coding, segmentation, categorising and theming. This research project is grounded in two theories, namely, progressive discipline theory and decentralisation of power theory. The researcher‟s use of progressive discipline as a framework of analysis is based on the fact that the theory focuses on discipline as a corrective measure and not a punitive measure. It also focuses on a series of steps in ii which the disciplinary action is taken each time an educator commits an act of misconduct. The decentralisation-of-power theory is used as a frame of reference because it states that a current trend in education reform is the decentralisation of decision-making powers from a central level to a school level, hence there is schoolbased management. The literature sourced for this study is also based on these two theories. Major findings were established, discussed and recommendations were made. The literature, together with the major findings, generally agreed that all schools had SMTs to manage schools on a day-to-day basis. It was also revealed that the discipline policy for educators was there in every school and was clear, actionable and was the product of collective participation. The onus is upon the capacity of the SMTs to implement the policy for the benefit of quality education. The findings and recommendations suggest that for the implementation of this discipline policy, SMTs must first improve the school culture and school climate.
- Full Text:
- Authors: Lishman, Bilibane Thabo
- Date: 2014
- Subjects: Educational Management and Policy
- Language: English
- Type: Masters, Ed
- Identifier: http://hdl.handle.net/11260/2353 , vital:41450
- Description: This research project was an attempt to determine School Management Teams (SMTs) management of teacher discipline at school using the discipline policy (code of conduct for educators) as a frame of reference. This was because procedures and processes for managing teacher discipline were new to principals and their SMTs. The main aim was to investigate the practices and experiences of SMTs regarding management of discipline policy for better or improved teacher conduct. Again, the study sought to understand and explain the gap between discipline policy and its implementation as SMTs seemed to be grappling with the implementation process thereof. The study is located in an interpretive and qualitative perspective where a case study research design was used. Face-to-face interviews were used to collect data from participants selected from two schools (school A and school B). The participants were sampled purposively out of a population of 245 principals and 245 site stewards. The principal and site steward of each school were interviewed because they were found to be relevant to the case of discipline policy implementation. The principal of each school represented the SMT while the site stewards represented the teaching staff. There were therefore four participants who contributed to data collection. During the data collection process, all issues of ethics like voluntary participation, permission, informed consent, confidentiality, anonymity and rights of participants were considered. As data were collected using face-to-face interviews, they were analysed qualitatively, using interim analysis of coding, segmentation, categorising and theming. This research project is grounded in two theories, namely, progressive discipline theory and decentralisation of power theory. The researcher‟s use of progressive discipline as a framework of analysis is based on the fact that the theory focuses on discipline as a corrective measure and not a punitive measure. It also focuses on a series of steps in ii which the disciplinary action is taken each time an educator commits an act of misconduct. The decentralisation-of-power theory is used as a frame of reference because it states that a current trend in education reform is the decentralisation of decision-making powers from a central level to a school level, hence there is schoolbased management. The literature sourced for this study is also based on these two theories. Major findings were established, discussed and recommendations were made. The literature, together with the major findings, generally agreed that all schools had SMTs to manage schools on a day-to-day basis. It was also revealed that the discipline policy for educators was there in every school and was clear, actionable and was the product of collective participation. The onus is upon the capacity of the SMTs to implement the policy for the benefit of quality education. The findings and recommendations suggest that for the implementation of this discipline policy, SMTs must first improve the school culture and school climate.
- Full Text:
Matuka et al 2020.pdf
- Authors: Oyedeji, Adebola Omowunmi
- Language: English
- Identifier: http://hdl.handle.net/11260/2493 , vital:41902
- Description: Various articles from Prof Adebola Oyedeji
- Full Text:
- Authors: Oyedeji, Adebola Omowunmi
- Language: English
- Identifier: http://hdl.handle.net/11260/2493 , vital:41902
- Description: Various articles from Prof Adebola Oyedeji
- Full Text:
May Measurement Month 2018: an analysis of blood pressure screening results in South Africa
- Angela J. Woodiwiss1, Ruan Kruger, Gavin R. Norton, Aletta E. Schutte, Caitlynd Myburgh
- Authors: Angela J. Woodiwiss1 , Ruan Kruger , Gavin R. Norton , Aletta E. Schutte , Caitlynd Myburgh
- Date: 2020
- Language: English
- Type: Journal Article
- Identifier: http://hdl.handle.net/11260/4331 , vital:44105
- Full Text:
- Authors: Angela J. Woodiwiss1 , Ruan Kruger , Gavin R. Norton , Aletta E. Schutte , Caitlynd Myburgh
- Date: 2020
- Language: English
- Type: Journal Article
- Identifier: http://hdl.handle.net/11260/4331 , vital:44105
- Full Text:
MEDIATING TEACHING AND LEARNING IN FOUNDATION PHASE GRADE 3 LIFE SKILLS CLASSROOMS : ROLE AN USE OF LEARNING AND TEACHING SUPPORT MATERIALS
- Authors: PELOKAZI NQABENI
- Subjects: Education
- Language: English
- Type: D Ed
- Identifier: http://hdl.handle.net/11260/2193 , vital:40912
- Full Text: false
- Authors: PELOKAZI NQABENI
- Subjects: Education
- Language: English
- Type: D Ed
- Identifier: http://hdl.handle.net/11260/2193 , vital:40912
- Full Text: false
Mentha JEOR copy.pdf
- Authors: Oyedeji, Adebola Omowunmi
- Language: English
- Identifier: http://hdl.handle.net/11260/2452 , vital:41901
- Description: Various articles from Prof Adebola Oyedeji
- Full Text:
- Authors: Oyedeji, Adebola Omowunmi
- Language: English
- Identifier: http://hdl.handle.net/11260/2452 , vital:41901
- Description: Various articles from Prof Adebola Oyedeji
- Full Text:
Meyer2020_Article_OpticalAndStructural-chemistry.pdf
- Edson L. Meyer, Johannes Z. Mbese, Raymond Taziwa, Mojeed A. Agoro
- Authors: Edson L. Meyer , Johannes Z. Mbese , Raymond Taziwa , Mojeed A. Agoro
- Language: English
- Type: Journal Article
- Identifier: http://hdl.handle.net/11260/4683 , vital:44159
- Full Text:
- Authors: Edson L. Meyer , Johannes Z. Mbese , Raymond Taziwa , Mojeed A. Agoro
- Language: English
- Type: Journal Article
- Identifier: http://hdl.handle.net/11260/4683 , vital:44159
- Full Text:
Molecular analysis and Photodynamic inactivation of multidrug-resistant strains of Acinetobacter baumannii from clinical, abattoir and aquatic samples: Public Health Impact
- Authors: ANANE YAW ADJEI
- Date: 2020
- Language: English
- Type: PhD Manuscripts
- Identifier: http://hdl.handle.net/11260/2080 , vital:40816 , DOCTOR OF PHILOSOPHY (PhD) HEALTH SCIENCES (MEDICAL MICROBIOLOGY)
- Description: Acinetobacter baumannii is an important hospital-acquired pathogen, frequently associated with morbidity and mortality in immunocompromised patients causing a wide range of clinical complications, such as pneumonia, septicaemia, urinary tract infection, surgical site infection, wound infection, and meningitis. Much of the interest in A. baumannii has been attributed to its genetic plasticity, with its ability to acquire and express resistance in plasmids and chromosome particularly to carbapenems, the drug of choice to treat Acinetobacter infections. Carbapenem resistance in A. baumannii is a growing public health concern and represents a serious problem for treatment of the infection. This situation is not restricted to only clinical settings but also occurs in the extra-hospital settings where these areas can serve as reservoirs for multidrug-resistant (MDR) A. baumannii. The increasing limited access of therapeutic agents against A. baumannii infections and the development of MDR have led to the necessity for alternative strategies to control infections caused by MDR pathogens. Antimicrobial Photodynamic Inactivation (APDI) is a promising treatment modality in the field of biocide research that in the future may have widespread applications, replacing conventional antibiotics. The overall aim of this study was to determine the efficacy of APDI against MDR A. baumannii isolated from clinical, aquatic and abattoir settings, to investigate carbapenem resistance mechanisms and the genetic relationship among isolates circulating in our settings in Mthatha, Eastern Cape, South Africa. The thesis consists of seven chapters. With the exception of chapters 1, 2 and 7, each chapter is designed as a publishable unit. iv The 1 st chapter gives a comprehensive account of the background to the study and the literature review. Here the history of classification, morphology, natural habitat, laboratory diagnosis, infections, epidemiology, virulence and pathogenicity, antimicrobial resistance, A. baumannii in extra-hospital environment (abattoir and aquatic environment), treatment options of A. baumannii and the mechanism of action of APDI were reviewed. Chapter 2 described the techniques and general methods used for sampling, identification, antimicrobial susceptibility testing, PCR extraction and amplification and sequencing processes involved in this work. It covers the general experimental section of chapters 3, 4, 5 and 6. Chapter 3 evaluated the prevalence of antibiotic resistance and frequency of carbapenemase-encoding genes as well as the roles of insertion sequence one (ISAba1) and class 1 integrons (intI1) in MDR A. baumannii clinical isolates obtained from the National Health Laboratory Service (NHLS) at Nelson Mandela Academic Hospital (NMAH). Between August 2016 to July 2017, 100 non-duplicate MDR A. baumannii strains were recovered from various clinical samples. Identification and antimicrobial susceptibility tests of the isolates were performed using the VITEK® 2 automated systems with Gram-negative identification cards and the MicroScan autoSCAN-4 system Gram-negative ID type 2 panel. Minimum inhibitory concentration to imipenem, meropenem and colistin was rechecked by E-test (BioMérieux, France). Colistin susceptibility testing was confirmed using broth microdilution method according to the CLSI and by ComASP™ Colistin according to the manufacturer’s recommendations. Suspected colonies were verified using v Acinetobacter specific primer set Ac436f and Ac676r to amplify the 16S rRNA gene and identification was further confirmed by PCR amplification of the intrinsic blaOXA51-like. The detection of oxacillinase carbapenemase genes (blaOXA-23-like, blaOXA-24-like, blaOXA-51-like and blaOXA-58-like) and metallo-β-lactamase (MBL) genes (blaIMP-1, blaVIM, blaNDM-1 and blaSIM) as well as blaAmpC was carried out by real-time PCR assay using Roche LightCycler 2.0. The occurrence of the activating ISAba1 element upstream of the blaOXA-23-like and blaOXA-51-like genes was also carried out in a PCR assay. Isolates were also assayed for intI1. All strains were resistant to penicillins and cephalosporins except cefepime (87%). Resistant rates against other tested antibiotics were as follows: piperacillin/tazobactam (100%), ampicillin/sulbactam (100%), levofloxacin (91%), ciprofloxacin (89%), tobramycin (87%), gentamicin (84%), meropenem (83%), imipenem (81%), tetracycline (64%), amikacin (50%) and tigecycline (48%). All strains were fully susceptible to colistin. The screening of carbapenemase-encoding genes showed that all strains were found to harbour at least one of the OXA-type carbapenemases. The intrinsic blaOXA-51-like gene was detected in all isolates, 70% of the strains had blaOXA-23-like, 5% had blaOXA-24-like and 8% had blaOXA-58-like genes. For the MBLs, 4% isolates were positive for blaIMP-1, 3% strains were positive for blaVIM and 2% positive for blaNDM-1. Genes encoding blaSIM and blaAmpC enzymes were absent in all the strains. Co-occurrence of blaOXA-23-like and blaIMP-1 or blaOXA-58-like was detected in 1% and 2% MDR A. baumannii strains respectively. A key feature of this study was the co-harbouring of blaOXA-23-like, blaOXA-58-like and blaIMP-1 detected in 2% of the strains and this is the first report in the Eastern Cape province of South Africa. The ISAba1/blaOXA-51-like and ISAba1/blaOXA-23-like were detected in 15% and 40% vi isolates respectively whilst intI1 was detected in 80% isolates. Our data revealed a high antibiotic resistance to carbapenems and provide direct evidence of the spread of carbapenemase-encoding genes especially blaOXA-23-like in our local settings. Also the high presence of ISAba1 element upstream of the blaOXA-51-like and blaOXA-23-like increases expression of these carbapenemases and presents an emerging threat in our study setting. The study has also revealed specific insights into the interplay of different mechanisms causing rapid increase in antibiotic resistance in A. baumannii in our local setting. To prevent the development of carbapenem-resistant A. baumannii (CRAB), routine implementation of simple and cost-effective screening methods to detect carbapenemase production in our hospitals is crucial in enhancing infection control practices and finally establishing antimicrobial stewardship programs. Chapter 4 investigated the prevalence of MDR A. baumannii strains in extra-hospital settings, to study its susceptibility to antibiotics and to determine the frequency of carbapenemase-encoding genes. Various samples were obtained from Umzikantu Red Meat Abattoir and Mthatha Dam. Isolates were presumptively identified by direct plating on chromogenic CHROMagar Acinetobacter with supplement Ref. CR102 which allows the growth of CRAB isolates. Species identification and antimicrobial susceptibility testing were carried out using MicroScan autoSCAN-4 automated System. Confirmation of A. baumannii isolates were carried out by PCR analysis of the presence of inherent blaOXA-51-like genes. The presence of the carbapenemase-encoding genes was assessed. Results for 48 and 52 MDR A. baumannii isolated recovered from the abattoir and dam respectively revealed a high resistance rate to some frequently used antimicrobials such as piperacillin [abattoir vii (84%), aquatic (73%)], ceftazidime [abattoir (84%), aquatic (83%)], ciprofloxacin [abattoir (71%), aquatic (70%)]. The percentage of resistant strains to trimethoprim/sulfamethoxazole, amikacin, gentamycin, cefotaxime, and cefepime in abattoir and aquatic isolates were (100%, 92%), (41%, 42%), (81%, 75%), (81%, 79%) and (72%, 72%) respectively. High resistance of (75%, 73%) and (74%, 71%) to imipenem and meropenem were observed in abattoir and aquatic strains respectively. The detection of carbapenemase-encoding genes showed that all MDR A. baumannii strain were positive for blaOXA-51-like. The blaOXA-23-like was detected in 32 (66.7%) of the abattoir strains whereas 11 (21.2%) of the aquatic strains had blaOXA23-like. The blaOXA-58-like was detected in 7 (14.6%) and 4 (7.7%) of abattoir and aquatic isolates respectively. No strain had blaOXA-24-like, blaIMP-type, blaVIM-type, blaNDM-1, blaSIM, and blaAmpC genes among both groups of strains. All the strains lacked ISAba1/blaOXA-23-like and ISAba1/blaOXA-51-like as well as intI1. A high level of multiple antibiotic resistance indexes ranging from 0.22-0.51 indicates that the strains emerged from high-risk sources, in line with conventional standards. In conclusion, the presence of MDR A. baumannii in the extra-hospital environment such as abattoir and aquatic environments may be a threat to public health considering that this may provide an extra-hospital reservoir for the spread of these opportunistic pathogen into both community and hospital settings. Chapter 5 was designed to investigate the genetic relationship among CRAB strains obtained from clinical and extra-hospital sources using the Pasteur MLST scheme. A phylogenetic analysis was performed on 33 representative proportions of A. baumannii strains from clinical, abattoir and aquatic sources. Multi-locus sequence typing was performed using seven fragments of housekeeping genes cpn60, fusA, viii gltA, pyrG, recA, rplB and rpoB provided by Pasteur Institute MLST. Five existing sequence types (STs) were identified in the clinical strains by eBURST algorithm. The most dominant ST for clinical strains was ST2 accounting for 68.8 % (n = 11), followed by ST25 12.5% (n = 2) and 3 STs (ST1, ST85 and ST215) represented by a single strain (singletons) were identified. Extra-hospital isolates had two existing STs, ST1 and ST2 identified in three and fourteen strains respectively. Clonal relation analysis revealed that ST1, ST2, ST25, ST85 and ST215 belonged to the CC1, CC2, CC25, CC85 and CC215 lineage respectively. Phylogenetic tree analysis show that most of the extra-hospital strains were related to each other and also did cluster among the clinical strains. Resistance to carbapenems was related to blaOXA-23-like (all strains), blaOXA-58-like (2 strains) and blaOXA-24-like (1 strain). This study highlights the wide dissemination of highly related blaOXA-23-like producing CRAB belonging to the international clonal complex 2 in Mthatha, South Africa. Thus, appropriate infection control measures are recommended in order to control this clone. As a whole, phylogenetic analysis provided a global view of the molecular epidemiology of A. baumannii in Mthatha, South Africa. In chapter 6, in vitro APDI effect mediated by Protoporphyrin IX (PpIX) and methylene blue (MB) as photosensitizers and with halogen lamp as a light source on A. baumannii biofilm was evaluated. Three MDR A. baumannii strains recovered from clinical, abattoir and aquatic samples were used. The irradiation source has a maximum light dose of 30 Jcm-2 . We studied the APDI according to low or high concentration of MB and PpIX along with exposure time. After treatment, the antibacterial effect of the APDI was assessed by counting colony-forming units per millilitre (CFU/mL). Antimicrobial photodynamic inactivation test groups (L+P1+ and ix L+P2+) showed significant reduction of CFUs compared to the control group (L−P−). The log survival fraction of the treated groups as a percentage of that of L−P− at a concentration of 20 µM is as follows: L+P1+ (5×10-6%), L+P2+ (2×10- 6%); L−P− (100%). (L+P2+ P = 0.0001). The most effective dye was MB which showed higher bacterial reduction of 7.0 log10 whilst PpIX yielded 6.0 log10 CFU/mL at a concentration of 20 µM and light dose of 30 Jcm-2 . Results showed that the efficacy of APDI is dependent on PpIX and MB concentration and light dose. Similar APDI effectiveness was achieved regardless of the origin and minimum inhibitory concentration of isolate indicating that regardless of the origin and resistant rate of isolate, similar APDI effectiveness could be reached. Lastly, general conclusions and recommendations on various parts of findings were captured in chapter 7. The study provides a comprehensive data and information on antimicrobial drug resistance, genes coding for resistance and phylogenetic profiles of local MDR A. baumannii strains and highlights the importance of surveillance. This is essential for epidemiological purposes and specifically in situation requiring empirical treatment. Also in vitro APDI could be considered as an alternative approach to traditional antibiotic therapy if there is an optimized interplay between combinations of different types of photosensitisers and their concentrations, exposure time and light dose. Further research studies employing whole genome sequencing and next generation sequencing, massively parallel or deep technologies are required to understand greater detail of these many unique findings
- Full Text:
- Authors: ANANE YAW ADJEI
- Date: 2020
- Language: English
- Type: PhD Manuscripts
- Identifier: http://hdl.handle.net/11260/2080 , vital:40816 , DOCTOR OF PHILOSOPHY (PhD) HEALTH SCIENCES (MEDICAL MICROBIOLOGY)
- Description: Acinetobacter baumannii is an important hospital-acquired pathogen, frequently associated with morbidity and mortality in immunocompromised patients causing a wide range of clinical complications, such as pneumonia, septicaemia, urinary tract infection, surgical site infection, wound infection, and meningitis. Much of the interest in A. baumannii has been attributed to its genetic plasticity, with its ability to acquire and express resistance in plasmids and chromosome particularly to carbapenems, the drug of choice to treat Acinetobacter infections. Carbapenem resistance in A. baumannii is a growing public health concern and represents a serious problem for treatment of the infection. This situation is not restricted to only clinical settings but also occurs in the extra-hospital settings where these areas can serve as reservoirs for multidrug-resistant (MDR) A. baumannii. The increasing limited access of therapeutic agents against A. baumannii infections and the development of MDR have led to the necessity for alternative strategies to control infections caused by MDR pathogens. Antimicrobial Photodynamic Inactivation (APDI) is a promising treatment modality in the field of biocide research that in the future may have widespread applications, replacing conventional antibiotics. The overall aim of this study was to determine the efficacy of APDI against MDR A. baumannii isolated from clinical, aquatic and abattoir settings, to investigate carbapenem resistance mechanisms and the genetic relationship among isolates circulating in our settings in Mthatha, Eastern Cape, South Africa. The thesis consists of seven chapters. With the exception of chapters 1, 2 and 7, each chapter is designed as a publishable unit. iv The 1 st chapter gives a comprehensive account of the background to the study and the literature review. Here the history of classification, morphology, natural habitat, laboratory diagnosis, infections, epidemiology, virulence and pathogenicity, antimicrobial resistance, A. baumannii in extra-hospital environment (abattoir and aquatic environment), treatment options of A. baumannii and the mechanism of action of APDI were reviewed. Chapter 2 described the techniques and general methods used for sampling, identification, antimicrobial susceptibility testing, PCR extraction and amplification and sequencing processes involved in this work. It covers the general experimental section of chapters 3, 4, 5 and 6. Chapter 3 evaluated the prevalence of antibiotic resistance and frequency of carbapenemase-encoding genes as well as the roles of insertion sequence one (ISAba1) and class 1 integrons (intI1) in MDR A. baumannii clinical isolates obtained from the National Health Laboratory Service (NHLS) at Nelson Mandela Academic Hospital (NMAH). Between August 2016 to July 2017, 100 non-duplicate MDR A. baumannii strains were recovered from various clinical samples. Identification and antimicrobial susceptibility tests of the isolates were performed using the VITEK® 2 automated systems with Gram-negative identification cards and the MicroScan autoSCAN-4 system Gram-negative ID type 2 panel. Minimum inhibitory concentration to imipenem, meropenem and colistin was rechecked by E-test (BioMérieux, France). Colistin susceptibility testing was confirmed using broth microdilution method according to the CLSI and by ComASP™ Colistin according to the manufacturer’s recommendations. Suspected colonies were verified using v Acinetobacter specific primer set Ac436f and Ac676r to amplify the 16S rRNA gene and identification was further confirmed by PCR amplification of the intrinsic blaOXA51-like. The detection of oxacillinase carbapenemase genes (blaOXA-23-like, blaOXA-24-like, blaOXA-51-like and blaOXA-58-like) and metallo-β-lactamase (MBL) genes (blaIMP-1, blaVIM, blaNDM-1 and blaSIM) as well as blaAmpC was carried out by real-time PCR assay using Roche LightCycler 2.0. The occurrence of the activating ISAba1 element upstream of the blaOXA-23-like and blaOXA-51-like genes was also carried out in a PCR assay. Isolates were also assayed for intI1. All strains were resistant to penicillins and cephalosporins except cefepime (87%). Resistant rates against other tested antibiotics were as follows: piperacillin/tazobactam (100%), ampicillin/sulbactam (100%), levofloxacin (91%), ciprofloxacin (89%), tobramycin (87%), gentamicin (84%), meropenem (83%), imipenem (81%), tetracycline (64%), amikacin (50%) and tigecycline (48%). All strains were fully susceptible to colistin. The screening of carbapenemase-encoding genes showed that all strains were found to harbour at least one of the OXA-type carbapenemases. The intrinsic blaOXA-51-like gene was detected in all isolates, 70% of the strains had blaOXA-23-like, 5% had blaOXA-24-like and 8% had blaOXA-58-like genes. For the MBLs, 4% isolates were positive for blaIMP-1, 3% strains were positive for blaVIM and 2% positive for blaNDM-1. Genes encoding blaSIM and blaAmpC enzymes were absent in all the strains. Co-occurrence of blaOXA-23-like and blaIMP-1 or blaOXA-58-like was detected in 1% and 2% MDR A. baumannii strains respectively. A key feature of this study was the co-harbouring of blaOXA-23-like, blaOXA-58-like and blaIMP-1 detected in 2% of the strains and this is the first report in the Eastern Cape province of South Africa. The ISAba1/blaOXA-51-like and ISAba1/blaOXA-23-like were detected in 15% and 40% vi isolates respectively whilst intI1 was detected in 80% isolates. Our data revealed a high antibiotic resistance to carbapenems and provide direct evidence of the spread of carbapenemase-encoding genes especially blaOXA-23-like in our local settings. Also the high presence of ISAba1 element upstream of the blaOXA-51-like and blaOXA-23-like increases expression of these carbapenemases and presents an emerging threat in our study setting. The study has also revealed specific insights into the interplay of different mechanisms causing rapid increase in antibiotic resistance in A. baumannii in our local setting. To prevent the development of carbapenem-resistant A. baumannii (CRAB), routine implementation of simple and cost-effective screening methods to detect carbapenemase production in our hospitals is crucial in enhancing infection control practices and finally establishing antimicrobial stewardship programs. Chapter 4 investigated the prevalence of MDR A. baumannii strains in extra-hospital settings, to study its susceptibility to antibiotics and to determine the frequency of carbapenemase-encoding genes. Various samples were obtained from Umzikantu Red Meat Abattoir and Mthatha Dam. Isolates were presumptively identified by direct plating on chromogenic CHROMagar Acinetobacter with supplement Ref. CR102 which allows the growth of CRAB isolates. Species identification and antimicrobial susceptibility testing were carried out using MicroScan autoSCAN-4 automated System. Confirmation of A. baumannii isolates were carried out by PCR analysis of the presence of inherent blaOXA-51-like genes. The presence of the carbapenemase-encoding genes was assessed. Results for 48 and 52 MDR A. baumannii isolated recovered from the abattoir and dam respectively revealed a high resistance rate to some frequently used antimicrobials such as piperacillin [abattoir vii (84%), aquatic (73%)], ceftazidime [abattoir (84%), aquatic (83%)], ciprofloxacin [abattoir (71%), aquatic (70%)]. The percentage of resistant strains to trimethoprim/sulfamethoxazole, amikacin, gentamycin, cefotaxime, and cefepime in abattoir and aquatic isolates were (100%, 92%), (41%, 42%), (81%, 75%), (81%, 79%) and (72%, 72%) respectively. High resistance of (75%, 73%) and (74%, 71%) to imipenem and meropenem were observed in abattoir and aquatic strains respectively. The detection of carbapenemase-encoding genes showed that all MDR A. baumannii strain were positive for blaOXA-51-like. The blaOXA-23-like was detected in 32 (66.7%) of the abattoir strains whereas 11 (21.2%) of the aquatic strains had blaOXA23-like. The blaOXA-58-like was detected in 7 (14.6%) and 4 (7.7%) of abattoir and aquatic isolates respectively. No strain had blaOXA-24-like, blaIMP-type, blaVIM-type, blaNDM-1, blaSIM, and blaAmpC genes among both groups of strains. All the strains lacked ISAba1/blaOXA-23-like and ISAba1/blaOXA-51-like as well as intI1. A high level of multiple antibiotic resistance indexes ranging from 0.22-0.51 indicates that the strains emerged from high-risk sources, in line with conventional standards. In conclusion, the presence of MDR A. baumannii in the extra-hospital environment such as abattoir and aquatic environments may be a threat to public health considering that this may provide an extra-hospital reservoir for the spread of these opportunistic pathogen into both community and hospital settings. Chapter 5 was designed to investigate the genetic relationship among CRAB strains obtained from clinical and extra-hospital sources using the Pasteur MLST scheme. A phylogenetic analysis was performed on 33 representative proportions of A. baumannii strains from clinical, abattoir and aquatic sources. Multi-locus sequence typing was performed using seven fragments of housekeeping genes cpn60, fusA, viii gltA, pyrG, recA, rplB and rpoB provided by Pasteur Institute MLST. Five existing sequence types (STs) were identified in the clinical strains by eBURST algorithm. The most dominant ST for clinical strains was ST2 accounting for 68.8 % (n = 11), followed by ST25 12.5% (n = 2) and 3 STs (ST1, ST85 and ST215) represented by a single strain (singletons) were identified. Extra-hospital isolates had two existing STs, ST1 and ST2 identified in three and fourteen strains respectively. Clonal relation analysis revealed that ST1, ST2, ST25, ST85 and ST215 belonged to the CC1, CC2, CC25, CC85 and CC215 lineage respectively. Phylogenetic tree analysis show that most of the extra-hospital strains were related to each other and also did cluster among the clinical strains. Resistance to carbapenems was related to blaOXA-23-like (all strains), blaOXA-58-like (2 strains) and blaOXA-24-like (1 strain). This study highlights the wide dissemination of highly related blaOXA-23-like producing CRAB belonging to the international clonal complex 2 in Mthatha, South Africa. Thus, appropriate infection control measures are recommended in order to control this clone. As a whole, phylogenetic analysis provided a global view of the molecular epidemiology of A. baumannii in Mthatha, South Africa. In chapter 6, in vitro APDI effect mediated by Protoporphyrin IX (PpIX) and methylene blue (MB) as photosensitizers and with halogen lamp as a light source on A. baumannii biofilm was evaluated. Three MDR A. baumannii strains recovered from clinical, abattoir and aquatic samples were used. The irradiation source has a maximum light dose of 30 Jcm-2 . We studied the APDI according to low or high concentration of MB and PpIX along with exposure time. After treatment, the antibacterial effect of the APDI was assessed by counting colony-forming units per millilitre (CFU/mL). Antimicrobial photodynamic inactivation test groups (L+P1+ and ix L+P2+) showed significant reduction of CFUs compared to the control group (L−P−). The log survival fraction of the treated groups as a percentage of that of L−P− at a concentration of 20 µM is as follows: L+P1+ (5×10-6%), L+P2+ (2×10- 6%); L−P− (100%). (L+P2+ P = 0.0001). The most effective dye was MB which showed higher bacterial reduction of 7.0 log10 whilst PpIX yielded 6.0 log10 CFU/mL at a concentration of 20 µM and light dose of 30 Jcm-2 . Results showed that the efficacy of APDI is dependent on PpIX and MB concentration and light dose. Similar APDI effectiveness was achieved regardless of the origin and minimum inhibitory concentration of isolate indicating that regardless of the origin and resistant rate of isolate, similar APDI effectiveness could be reached. Lastly, general conclusions and recommendations on various parts of findings were captured in chapter 7. The study provides a comprehensive data and information on antimicrobial drug resistance, genes coding for resistance and phylogenetic profiles of local MDR A. baumannii strains and highlights the importance of surveillance. This is essential for epidemiological purposes and specifically in situation requiring empirical treatment. Also in vitro APDI could be considered as an alternative approach to traditional antibiotic therapy if there is an optimized interplay between combinations of different types of photosensitisers and their concentrations, exposure time and light dose. Further research studies employing whole genome sequencing and next generation sequencing, massively parallel or deep technologies are required to understand greater detail of these many unique findings
- Full Text:
Molecular Detection of Antibiotic-Resistant Genes in Pseudomonas aeruginosa from Nonclinical Environment: Public Health Implications in Mthatha, Eastern Cape Province, South Africa
- Mojisola Clara Hosu, Sandeep Vasaikar, Grace Emily Okuthe, Teke Apalata
- Authors: Mojisola Clara Hosu , Sandeep Vasaikar , Grace Emily Okuthe , Teke Apalata
- Date: 5 January 2021
- Subjects: Microbiology
- Language: English
- Type: Journal Article
- Identifier: http://hdl.handle.net/11260/2417 , vital:41877
- Description: Evaluation of resistant profiles and detection of antimicrobial-resistant genes of bacterial pathogens in the nonclinical milieu is imperative to assess the probable risk of dissemination of resistant genes in the environment. .is paper sought to identify antibiotic-resistant genes in Pseudomonas aeruginosa from nonclinical sources in Mthatha, Eastern Cape, and evaluate its public health implications. Samples collected from abattoir wastewater and aquatic environment were processed by membrane filtration and cultured on CHROMagarTM Pseudomonas medium. Species identification was performed by autoSCAN-4 (Dade Behring Inc., IL). Molecular characterization of the isolates was confirmed using real-time polymerase chain reaction (rPCR) and selected isolates were further screened for the possibility of harboring antimicrobial resistance genes. Fifty-one Pseudomonas species were recovered from abattoir wastewater and surface water samples, out of which thirty-six strains were Pseudomonas aeruginosa (70.6%). .e P. aeruginosa isolates demonstrated resistance to aztreonam (86.1%), ceftazidime (63.9%), piperacillin (58.3%), cefepime (55.6%), imipenem (50%), piperacillin/tazobactam (47.2%), meropenem (41.7%), and levofloxacin (30.6%). Twenty out of thirty-six P. aeruginosa displayed multidrug resistance profiles and were classified as multidrug-resistant (MDR) (55.6%). Most of the bacterial isolates exhibited a high Multiple Antibiotic Resistance (MAR) Index ranging from 0.08 to 0.69 with a mean MAR index of 0.38. In the rPCR analysis of fifteen P. aeruginosa isolates, 14 isolates (93.3%) were detected harboring blaSHV, six isolates (40%) harbored blaTEM, and three isolates (20%) harbored blaCTX-M, being the least occurring ESBL. Results of the current study revealed that P. aeruginosa isolates recovered from nonclinical milieu are resistant to frontline clinically relevant antipseudomonal drugs. .is is concerning as it poses a risk to the environment and constitutes a public health threat. Given the public health relevance, the paper recommends monitoring of multidrug-resistant pathogens in effluent environments.
- Full Text:
- Authors: Mojisola Clara Hosu , Sandeep Vasaikar , Grace Emily Okuthe , Teke Apalata
- Date: 5 January 2021
- Subjects: Microbiology
- Language: English
- Type: Journal Article
- Identifier: http://hdl.handle.net/11260/2417 , vital:41877
- Description: Evaluation of resistant profiles and detection of antimicrobial-resistant genes of bacterial pathogens in the nonclinical milieu is imperative to assess the probable risk of dissemination of resistant genes in the environment. .is paper sought to identify antibiotic-resistant genes in Pseudomonas aeruginosa from nonclinical sources in Mthatha, Eastern Cape, and evaluate its public health implications. Samples collected from abattoir wastewater and aquatic environment were processed by membrane filtration and cultured on CHROMagarTM Pseudomonas medium. Species identification was performed by autoSCAN-4 (Dade Behring Inc., IL). Molecular characterization of the isolates was confirmed using real-time polymerase chain reaction (rPCR) and selected isolates were further screened for the possibility of harboring antimicrobial resistance genes. Fifty-one Pseudomonas species were recovered from abattoir wastewater and surface water samples, out of which thirty-six strains were Pseudomonas aeruginosa (70.6%). .e P. aeruginosa isolates demonstrated resistance to aztreonam (86.1%), ceftazidime (63.9%), piperacillin (58.3%), cefepime (55.6%), imipenem (50%), piperacillin/tazobactam (47.2%), meropenem (41.7%), and levofloxacin (30.6%). Twenty out of thirty-six P. aeruginosa displayed multidrug resistance profiles and were classified as multidrug-resistant (MDR) (55.6%). Most of the bacterial isolates exhibited a high Multiple Antibiotic Resistance (MAR) Index ranging from 0.08 to 0.69 with a mean MAR index of 0.38. In the rPCR analysis of fifteen P. aeruginosa isolates, 14 isolates (93.3%) were detected harboring blaSHV, six isolates (40%) harbored blaTEM, and three isolates (20%) harbored blaCTX-M, being the least occurring ESBL. Results of the current study revealed that P. aeruginosa isolates recovered from nonclinical milieu are resistant to frontline clinically relevant antipseudomonal drugs. .is is concerning as it poses a risk to the environment and constitutes a public health threat. Given the public health relevance, the paper recommends monitoring of multidrug-resistant pathogens in effluent environments.
- Full Text:
Molecular Detection of Carbapenemase-Encoding Genes in Multidrug-Resistant Acinetobacter baumannii Clinical Isolates in South Africa
- Anane, Yaw Adjei, Okuthe, Grace Emily, Apalata, Teke, Vasaikar, Sandeep, Songca, Sandile
- Authors: Anane, Yaw Adjei , Okuthe, Grace Emily , Apalata, Teke , Vasaikar, Sandeep , Songca, Sandile
- Date: 2020
- Language: English
- Type: Journal Article
- Identifier: http://hdl.handle.net/11260/4351 , vital:44108
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- Authors: Anane, Yaw Adjei , Okuthe, Grace Emily , Apalata, Teke , Vasaikar, Sandeep , Songca, Sandile
- Date: 2020
- Language: English
- Type: Journal Article
- Identifier: http://hdl.handle.net/11260/4351 , vital:44108
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Molecule full paper on Callistemon.pdf
- Authors: Oyedeji, Adebola Omowunmi
- Language: English
- Identifier: http://hdl.handle.net/11260/2470 , vital:41903
- Description: Various articles from Prof Adebola Oyedeji
- Full Text:
- Authors: Oyedeji, Adebola Omowunmi
- Language: English
- Identifier: http://hdl.handle.net/11260/2470 , vital:41903
- Description: Various articles from Prof Adebola Oyedeji
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