Researcher Profile and List of Publications Dominic Abaver.pdf
- Authors: Abaver, Dominic, Targema
- Identifier: http://hdl.handle.net/11260/4799 , vital:44256
- Description:
Expertise:
Public Health/Medical Microbiology
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In vitro antimicrobial photodynamic inactivation of multidrugresistant Acinetobacter baumannii biofilm using Protoporphyrin IX and Methylene blue
- Authors: Anane, Yaw Adjei , Apalata, Teke , Vasaikar, Sandeep , Okuthe, Grace Emily , Songca, Sandile Phinda
- Date: 2020
- Language: English
- Identifier: http://hdl.handle.net/11260/2273 , vital:41315
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Molecular Detection of Carbapenemase-Encoding Genes in Multidrug-Resistant Acinetobacter baumannii Clinical Isolates in South Africa
- Authors: Anane, Yaw Adjei , Apalata, Teke , Vasaikar, Sandeep , Okuthe, Grace Emily , Songca, Sandile
- Date: 2020
- Language: English
- Type: Journal Article
- Identifier: http://hdl.handle.net/11260/2263 , vital:41314
- Description: https://www.hindawi.com/journals/ijmicro/2020/7380740/
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Molecular Detection of Carbapenemase-Encoding Genes in Multidrug-Resistant Acinetobacter baumannii Clinical Isolates in South Africa
- 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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Epidemiology, risk factors and molecular analysis of carbapenem-resistant Enterobacteriaceae (CRE) in Mthatha, Eastern Cape, South Africa
- Authors: S.D. Vasaikar 1 , P. Hanise , D.T. Abaver
- Date: 2020
- Language: English
- Type: Journal article
- Identifier: http://hdl.handle.net/11260/3908 , vital:43965
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Epidemiology, risk factors and molecular analysis of carbapenem-resistant Enterobacteriaceae (CRE) in Mthatha, Eastern Cape, South Africa:
- Authors: S.D.Vasaikar , P.Hanise , D.T.Abaver
- Date: 2021
- Subjects: Epidemiology Carbapenem-resistant Enterobacteriaceae Mthatha
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/3129 , vital:43143 , xlink:href="https://doi.org/10.3390/f10060467"
- Description: Abstract text. Background: The emergence of carbapenem resistance in Enterobacteriaceae is an important threat to global health. Reported outcomes of infections with carbapenem-resistant Enterobacteriaceae (CRE) are poor. Commonly used antibiotics are generally inactive against CRE. Therefore, timely detection of CRE is of paramount importance. This study aimed to investigate the resistance genes responsible for CRE in Mthatha and to identify risk factors. Methods and materials: Study design – Prospective cohort study. Study period – 23 April to 27 September 2019. Setting – Eastern Cape province, SA. Study population – All adult and paediatric CRE patients. CRE case definition according to CDC 2018. ID and AST-bioMérieux Vitek 2 system. Detection of the blaOXA-48, blaKPC, blaNDM, and blaVIM by the RESIST-4 OKNV assay (Coris). Patients were interviewed to determine risk factors associated with CRE. Results: Forty-four non-duplicate CRE patients were identified during the study period from microbiology lab at NMAH. Enterobacteriaceae species: K. pneumoniae 22 (61.4%), E. cloacae 10 (22.7%), E. coli 2 (4.5%) and K. oxytoca, P. rettgeri and M. morganii 1 each (4.3%). Adult patient 29 (65.9%0 and paediatric 15 (34.1%). Race: all black patients except one white. CRE genes-blaOXA-48 22 (50%), blaNDM 8 (18.2%), two isolates (4.5%) with both blaOXA and blaNDM. We did not find any blaKPC and blaVIM in our setting and 12 (27.2%) isolates were negative for all OKNV. Outcomes: Demised 18 (40.9%), still admitted in the ward 1 (2.3%), discharged home on basis of clinical grounds 22 (50%) and 3 (6.8%) were transferred back to the district hospitals. HAI in 27 (61.4%) with VAP 8, HABSI 8, CAUTI 5, SSI 3 and CLABSI in 3. Risk factors for CRE acquisition were antibiotic exposure 25 (58.7%), ICU stay 7 (15.9%), received medical care in last 6 months 35 (79.6%) and none travelled outside RSA. HIV positive – 19 (43.2%). Conclusion: In out setting our CRE mortality rate is 40.9%, common CRE genotypes are blaOXA-48 and blaNDM. K. pneumoniae is the most common CRE-producing Enterobacteriaceae and antibiotic exposure is an important risk factor in Mthatha and surrounding areas.
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- Date Issued: 2021
Molecular Detection of Antibiotic-Resistant Genes in Pseudomonas aeruginosa from Nonclinical Environment: Public Health Implications in Mthatha, Eastern Cape Province, South Africa
- 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.
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Prevalence of macrolide and fluoroquinolone resistance-associated mutations in Mycoplasma genitalium in Hong Kong
- Authors: P.C.D. Chan , K.M. Kam1 , C.K. Kwan , P.H. Chung
- Date: 202
- Language: English
- Type: Journal article
- Identifier: http://hdl.handle.net/11260/3919 , vital:43970
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Devising communication strategies for improving public awareness on responsible antibiotic use: A case study of WHO campaign
- Authors: D. Bhaskar
- Date: 2020
- Language: English
- Type: Journal article
- Identifier: http://hdl.handle.net/11260/3930 , vital:43972
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Outcomes and Risk Factors Associated with Drug Resistant Tuberculosis in Rural Eastern Cape, South Africa.pdf
- Identifier: http://hdl.handle.net/11260/5058 , vital:44312
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Researcher Profile and List of Publications - Oyedeji.pdf
- Authors: Oyedeji, Adebola Omowunmi
- Identifier: http://hdl.handle.net/11260/4791 , vital:44254
- Description: Expertise: Organic chemistry-Natural Product Chemist
- Full Text:
Professor
- Authors: Oyedeji, Adebola Omowunmi
- Type: Researcher Profile
- Identifier: http://hdl.handle.net/11260/2721 , vital:42330
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Detection of extended spectrum beta‑lactamase genes in Pseudomonas aeruginosa isolated from patients in rural Eastern Cape Province, South Africa
- Authors: Mojisola C. Hosu , Sandeep D. Vasaikar, , Grace E. Okuthe , Teke Apalata
- Date: 2021
- Language: English
- Type: Journal Article
- Identifier: http://hdl.handle.net/11260/4509 , vital:44128
- Description: The proliferation of extended spectrum beta-lactamase (ESBL) producing Pseudomonas aeruginosa represent a major public health threat. In this study, we evaluated the antimicrobial resistance patterns of P. aeruginosa strains and characterized the ESBLs and Metallo- β-lactamases (MBL) produced. Strains of P. aeruginosa cultured from patients who attended Nelson Mandela Academic Hospital and other clinics in the four district municipalities of the Eastern Cape between August 2017 and May 2019 were identified; antimicrobial susceptibility testing was carried out against thirteen clinically relevant antibiotics using the BioMérieux VITEK 2 and confirmed by Beckman autoSCAN-4 System. Real-time PCR was done using Roche Light Cycler 2.0 to detect the presence of ESBLs; blaSHV, blaTEM and blaCTX-M genes; and MBLs; blaIMP, blaVIM. Strains of P. aeruginosa demonstrated resistance to wide-ranging clinically relevant antibiotics including piperacillin (64.2%), followed by aztreonam (57.8%), cefepime (51.5%), ceftazidime (51.0%), piperacillin/tazobactam (50.5%), and imipenem (46.6%). A total of 75 (36.8%) multidrug-resistant (MDR) strains were observed of the total pool of isolates. The blaTEM, blaSHV and blaCTX-M was detected in 79.3%, 69.5% and 31.7% isolates (n = 82), respectively. The blaIMP was detected in 1.25% while no blaVIM was detected in any of the strains tested. The study showed a high rate of MDR P. aeruginosa in our setting. The vast majority of these resistant strains carried blaTEM and blaSHV genes. Continuous monitoring of antimicrobial resistance and strict compliance towards infection prevention and control practices are the best defence against spread of MDR P. aeruginosa.
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Prevalence and molecular analysis of multidrug-resistant Acinetobacter baumannii in the extra-hospital environment in Mthatha, South Africa
- Authors: Adjei, Anane Yaw , Apalata, Teke , Vasaikar, Sandeep , Okuthe, Grace Emily , Songca, Sandile
- Date: 2019
- Subjects: Acinetobacter baumannii , Carbapenemase-encoding genes , Multidrug-resistance , ISAba1 , intI1
- Language: English
- Type: article , text
- Identifier: http://hdl.handle.net/11260/2409 , vital:41457 , https://doi.org/10.1016/j.bjid.2019.09.004
- Description: The presence of Acinetobacter baumannii outside hospitals remains unclear. This study aimed to determine the prevalence of multidrug-resistance (MDR) A. baumannii in the extra-hospital environment in Mthatha, South Africa and to investigate the frequency of carbapenemase-encoding genes. Material and Methods: From August 2016 to July 2017 a total of 598 abattoir samples and 689 aquatic samples were collected and analyzed presumptively by cultural methods for the presence of A. baumannii using CHROMagarTM Acinetobacter medium. Species identification was performed by autoSCAN-4 (Dade Behring Inc., IL) and confirmed by the detection of their intrinsic blaOXA-51 gene. Confirmed MDR A. baumannii isolates were screened for the presence of carbapenemase-encoding genes, ISAba1 insertion sequence and integrase intI1. Results: In total, 248 (19.3%) Acinetobacter species were isolated. Acinetobacter. baumannii was detected in 183 (73.8%) of which 85 (46.4%) and 98 (53.6%) were recovered from abattoir and aquatic respectively. MDR A. baumannii was detected in 56.5% (48/85) abattoir isolates and 53.1% (52/98) aquatic isolates. Isolates showed high resistance to antimicrobials most frequently used to treat Acinetobacter infections such as piperacillin/tazobactam; abattoir (98% of isolates resistant), aquatic (94% of isolates resistant), ceftazidime (84%, 83%), ciprofloxacin (71%, 70%), amikacin (41%, 42%), imipenem (75%, 73%), and meropenem (74%, 71%). All the isolates were susceptible to tigecycline and colistin. All the isolates carried blaOXA-51-like. The blaOXA-23 was detected in 32 (66.7%) abattoir isolates and 11 (21.2%) aquatic isolates. The blaOXA-58-like was positive in 7 (14.6%) and 4 (7.7%) abattoir and aquatic isolates, respectively. Both groups of isolates lacked blaOXA-24-like, blaIMP-type, blaVIM-type, blaNDM-1, blaSIM, blaAmpC, ISAba1 and inI1. Isolates showed high level of Multiple Antibiotic Resistance Index (MARI) ranging from 0.20-0.52. Conclusion: Extra-hospital sources such as abattoir and aquatic environments may be a vehicle of spread of MDR A. baumannii strains in the community and hospital settings.
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- Date Issued: 2019
Species distribution and antifungal susceptibility patterns of Candida isolates from a public tertiary teaching hospital in the Eastern Cape Province, South Africa
- Authors: Mnge, P , Okeleye, B I , Vasaikar, S D , Apalata, T
- Date: 2017-03-14
- Subjects: Candida Candida species , Antifungal agents Antifungal susceptibility
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/6817 , vital:49389 , http://dx.doi.org/10.1590/1414-431X20175797
- Description: Candida species are the leading cause of invasive fungal infections, and over the past decade there has been an increased isolation of drug resistant Candida species. This study aimed to identify the species distribution of Candida isolates and to determine their unique antifungal susceptibility and resistance patterns. During a cross-sectional study, 209 Candida isolates (recovered from 206 clinical samples) were collected and their species distribution was determined using ChromAgar Candida. The Vitek-2 system (Biomerieux, South Africa) was used to determine minimum inhibitory concentrations (MICs) to azoles (fluconazole, voriconazole), echinocandins (caspofungin, micafungin), polyenes (amphotericin B) and flucytosine. Four species of Candida were isolated, of which C. albicans was the most frequent, isolated in 45.4 percent (95/209) of the isolates, followed by C. glabrata: 31.1 percent (65/209). The MICs of the different antifungal drugs varied amongst the species of Candida. From the 130 isolates tested for MICs, 90.77 percent (112/130) were susceptible to all antifungal drugs and 6.9 percent (9/130) of the isolates were multi-drug resistant. C. dubliniensis (n=2) isolates were susceptible to all the above mentioned antifungal drugs. There was no significant difference in species distribution amongst clinical specimens and between patients’ genders (P40.05). An increase in MIC values for fluconazole and flucytosine towards the resistance range was observed. To our knowledge, this is the first report on surveillance of Candida species distribution and antifungal susceptibility at a public tertiary teaching hospital in Eastern Cape, South Africa.
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- Date Issued: 2017-03-14
Molecular characterization, antibiograms and antibacterial activities of selected medicinal plants against some enteric pathogens
- Authors: Bisi-Johnson, Mary Adejumoke
- Date: 2011
- Subjects: Diarrhea Diarrhea in children -- Complications Medicinal plants
- Language: English
- Type: Thesis , Doctoral , Ph D
- Identifier: vital:18475 , http://hdl.handle.net/11260/d1006643
- Description: Diarrhea diseases remain one of the greatest health problems in many parts of the world. In some cases, the disease is mild and self-limiting; however, the symptoms may be very severe in the elderly and young children (Smith and Cheasty, 1998), as well as in immune compromised patients such as HIV/AIDS patients. The disease is one of the hallmarks of HIV/AIDS in developing countries and is also a cardinal clinical manifestation of water borne infections (Obi et al., 2007). According to a World Health Organization report (WHO, 2004), diarrhea was rated second, after respiratory infections out of the eight deadliest diseases worldwide and was responsible for 1.8 million deaths per year. This infectious disease which can cause dehydration is primarily a symptom of gastrointestinal infection, but chemical irritation of the gut or non-infectious bowel disease can also result in diarrhoe. Studies have shown that the predominant causative agents of acute and persistent diarrhoe are Gram-negative rods such as Escherichia coli, Vibrio cholerae, Aeromonas, Campylobacter, Salmonella species, Shigella species, Plesiomonas shigelloides and Yersinia enterocolitica (Obi et al., 1995, 1998, 2003; Lainson and Silva, 1999; Coker et al., 2002; Oyofo et al., 2002). Aside from bacterial agents of diarrhoea, other causative pathogens include protozoa such as Giardia lamblia and Cryptosporidium parvum; viruses such as norwalk virus and rota virus. Although fungal agents such as Candida have been shown to be prevalent in children with diarrhoe (Enweani et al. 1994), a more recent study (Forbes et al., 2001), associated higher Candida counts with recent antibiotic use. Faecal concentrations of Candida were higher in patients with diarrhoe, but the study confirmed no association between faecal candida or other yeasts and diarrhoe. Norwalk viruses, calci-like viruses and rota viruses are the major viral agents of diarrhoe. According to Parashar et al., (2006), rota virus is the leading cause of diarrhoe hospitalisation among children worldwide, causing 440,000 annual deaths in children under 5 years of age.
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- Date Issued: 2011
Isolation and Biological Investigation of Bioactive Compounds from Croton grattissimus (Burch) in Mthatha, Eastern Cape, South Africa
- Authors: Oyedeji A.0 , Vasaikar SD
- Date: 2018
- Subjects: Croton grattisimus (Burch); Aromatic plants; Sexually transmitted diseases; Antimicrobial activity; Triterpenoids
- Identifier: http://hdl.handle.net/11260/1560 , vital:37785
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Agreement and coordination in XiTsonga, SeSotho and IsiXhosa: an optimality theoretic perspective
- Authors: Mitchley, Hazel
- Date: 2016
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/3423 , vital:20491
- Description: This thesis provides a unified Optimality Theoretic analysis of subject-verb agreement with coordinated preverbal subjects in three Southern Bantu languages: Xitsonga (S53), Sesotho (S33), and isiXhosa (S41). This analysis is then used to formulate a typology of agreement resolution strategies and the contexts which trigger them. Although some accounts in the Bantu literature suggest that agreement with coordinate structures is avoided by speakers (e.g. Schadeberg 1992, Voeltz 1971) especially when conjuncts are from different noun classes, I show that there is ample evidence to the contrary, and that the subject marker used is dependent on several factors, including (i) the [-HUMAN] specification on the conjuncts, (ii) whether the conjuncts are singular or plural, (iii) whether or not the conjuncts both carry the same noun class feature, and (iv) the order of the conjuncts. This thesis shows that there are various agreement resolution strategies which can beused: 1) agreement with the [+HUMAN] feature on the conjuncts, 2) agreement with the[-HUMAN] feature on the conjuncts, 3) agreement with the noun class feature on both conjuncts, 4) agreement with the noun class feature on the conjunct closest to the verb, and 5) agreement with the noun class feature on the conjunct furthest from the verb. Not all of these strategies are used by all languages, nor are these strategies interchangeable in the languages which do use them – instead, multiple factors conspire to trigger the use of a specific agreement strategy within a specific agreement featural context. I show that these effects can be captured using Optimality Theory (Prince and Smolensky 2004). The analysis makes use of seven constraints: RES#, MAX[+H], MAX[-H], DEP[-H], MAXNC, DEPNC, and AGREECLOSEST. The hierarchical ranking of these constraints not only accounts for the confinement of particular strategies to specific agreement featural contexts within a language, but also accounts for the cross-linguistic differences in the use of these strategies. I end off by examining the typological implications which follow from the OT analysis provided in this thesis.
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- Date Issued: 2016
Molecular characterization, antibiograms and activity of medicinal plants against streptococcus pneumoniae and haemophilus influenzae isolates from clinical samples of patients in the Eastern Cape province, South Africa
- Authors: Morobe, Isaac Christopher
- Date: 2015-00
- Subjects: Medicinal plants
- Language: English
- Type: Master's/Doctoral theses , text
- Identifier: http://hdl.handle.net/11260/6469 , vital:46340
- Description: H. influenzae and S. pneumoniae are important causes of community acquired respiratory tract infections including, pneumonia, acute sinusitis, otitis media, meningitis, bacteremia, sepsis, osteomyelitis, pericarditis, septic arthritis, endocarditis, peritonitis, cellulitis and brain abscesses. The ability to effectively treat bacterial infections has been compromised in recent years due to the acquisition of antibiotic resistance, particularly to β-lactam drugs. The increasing trends in antibiotic resistance have prompted incessant searches aimed at unraveling new effective sources for the management of microbial infections. Plant derived antimicrobial compounds that have no or minimal toxicity to host cells are considered candidates for developing new antimicrobial drugs. Safety is therefore critical in the development and formulation of such antimicrobials. In addition to studies on the structural elucidation of active compounds of selected medicinal plants and determination of their toxicity levels, concerted investigations on the molecular landscape of the designated bacteria, including genes coding for resistance and virulence, the phylogenetic profiles of isolates from different sources and the abilities of isolates to withstand the normal bactericidal activities of human serum samples from different blood groups are critical for a thorough understanding of the management, pathogenetic and clinico- epidemiological trajectories of the pathogens. Therefore, the aims of the various studies were to characterize local H. influenzae and S. pneumoniae isolates by serological and molecular methods; ascertain the antibiotic susceptibility profiles of isolates in order to provide updated data and guide clinicians and other health care workers on the empiric management of patients; determine genes coding for virulence and phylogenetic relatedness of isolates of H. influenzae and S. pneumoniae from diverse sources; ascertain the bactericidal activity of human serum samples from different blood groups against H. influenzae and S. pneumoniae and also to determine the activity of active compounds and toxicity levels of selected medicinal plants. In order to achieve these goals, relevant samples were collected and screened using an array of microbiological, serological, molecular and phytochemical methods, which would be espoused in the relevant chapters, presented hereunder. Key findings of the various chapters including their contributions to knowledge are highlighted. The studies are presented in eight chapters and each chapter, with the exception of chapter one (General Introduction and Literature Review) consists of an introduction, materials and methods, results, discussions, conclusions and references. Each chapter is therefore designed as a publishable unit. Chapter 1 gives an account of the background to the study and the literature review. The morphology, cultural characteristics, laboratory diagnosis, pathogenesis, antibiogram and clinical manifestations of H. influenzae and S. pneumoniae were reviewed. Furthermore, the activities of medicinal plants and their various applications in the management of infections in different countries, including their possible active compounds and toxicity levels were also explored in order to provide a suitable background for the study. Similar reviews were undertaken for molecular aspects of both pathogens as well as the activities of human serum samples against microbial infections. In Chapter 2 the prevalence and antibiotic resistance profiles of H. influenzae and, S. pneumoniae isolates from clinical samples of patients in Mthatha, Eastern Cape Province were investigated. Clinical samples were obtained randomly from individuals attending different hospitals in Mthatha district. Samples were analysed using the Kirby Bauer disk diffusion test (antibiotic susceptibility testing) and MIC breakpoints were determined using E-test strips. From a total of 475 clinical samples tested, 323 (68.0%) were positive for both H. influenzae and S. pneumoniae. Most of the positive isolates were obtained from children under 9 years. Out of 323 isolates, 187 (57.89%) were positive for H. influenzae and 136 (42.1%) were positive for S. pneumoniae. From 10 hospitals selected for sampling in this study, Mthatha General Hospital recorded the highest number of isolates, 42 (25.15%) and 31 (22.79%) of H. influenzae and S. pneumoniae positive isolates respectively, followed by Nelson Mandela Academic Hospital 33 (19.76%) and 26 (19.12%) respectively while ST. Patricks 8 (4.79%) recorded the least number of isolates for H. influenzae and Khotsong 4 (2.94%) recorded the least number of isolates for S. pneumoniae. Antibiotic susceptibility tests revealed Amoxicillin (MIC50, 0.125μg/ml) and Vancomycin (MIC50,0.12μg/ml) as the most effective antibiotics against S. pneumoniae isolates and Co-amoxiclav (MIC50,0.3µg/ml) and Cefuroxime (MIC50,0.15µg/ml) against H. influenzae isolates. These data highlight the need for education and to consider predominant resistance when choosing empiric therapies to treat bacterial infections. Chapter 3 was designed to investigate the virulence factors of H. influenzae and S. pneumoniae isolates from clinical specimens of patients with respiratory tract infections in Mthatha district, the Eastern Cape Province. PCR and sequencing methods were used to verify the genetic determinants responsible for virulence in H. influenzae and S. pneumoniae strains. Results indicated that, of the 187 H. influenzae isolates studied, 26 (13.9%) were typeable, positive by genotypic determination, while 161 (86.1%) were non typeable (NTHi) strains. On the other, out of the 136 S. pneumoniae isolates 24 (17.6%) were typeable while 112 (82.4%) were non typeable strains. All isolates tested contained the metS2 gene for both H. influenzae and S. pneumoniae. The phylogenetic clusters identified by maximum-parsimony analysis were also compared to the results of 16S rRNA sequences. Twenty five percent of none typeable strains were typed by 16S rRNA sequencing. The phylogenetic tree yielded 7.7% H. influenzae similarities while S. pneumoniae yielded 25% similarities with other typeable strains. The presence of genes coding for virulence in this study suggest a significant contribution of genes encoding for virulence to antimicrobial resistance among respiratory tract organisms studied. This study underlines the importance of understanding the virulence composition and diversity of pathogens for enhanced clinico-epidemiological monitoring and health care delivery. The findings will also provide a genetic foundation for future research into mechanisms of pathogenesis of H. influenzae and S. pneumoniae and may accelerate the development of safe and effective vaccines to prevent and control diseases caused by H. influenzae and S. pneumoniae. In Chapter 4, cytotoxic effects and safety profiles of extracts of active medicinal plants from the OR Tambo District Municipality in the Eastern Cape of South Africa were carried out. The most prominent families of medicinal plants (Solanacea and Euphorbiaceae) were used. Extracts of nine South African medicinal plants were screened for cytotoxic activities against MAGI CC5+ cells using MTT assay. Results indicated that nine plant extracts (methanolic and aqueous) used in the MTT assay revealed Herb 2 (Cyanthula inculata) as the most potent extract identified with activity of 1.4 Cc50 values of 25.6 mg/mL and induced over 50% of cell deaths, followed by herb 3 (Croton grattismus) and Herb 4 (Cassine trasvaalensis) with activity of 0.2 Cc50 values of 3.7 mg/mL each. The herbs that induced the least cell death, were herbs 5 (Capris tomentosa) and 7 (Hypoxis hemerocallidea), with the activity of 0.05 Cc50 values of 0.9 mg/mL each. Of the nine plant extracts 2(22%) exhibited minimal toxicity on MAGI cells and 7(77.8%) exhibited 50% toxicity. Two (22%) of the methanolic extracts exhibited anti-HIV1 IIIB activities and against Mycobacterium tuberculosis (TB) only one medicinal plant extract (Lysium inerme) exhibited 29% activity. Cytotoxicity tests will provide comprehensive reference data bases for the profiling and eventual considerations of medicinal plants as potential templates for drug designs and medical applications. In chapter 5 Chemical Components of the volatile and non-volatile extractives of Croton species and their microbial activities were screened. Isolation of the essential oils from the leaves of Croton pseudopulchellus and C. gratissimus from the Eastern Cape and KwaZulu-Natal Provinces in South Africa were performed using an all glass Clevenger apparatus according to the British Pharmacopeia method. The minimum inhibitory concentrations of the oils were assessed against the seven different standard strains of bacteria: H. influenzae, Bacillus pimitus, Staphylococcus aureus, S. pneumoniae, Escherichia coli, Klebsiella pneumoniae, Serratia marcescens and Entarobacter cloacae using micro dilution technique on a 96 well microtitre plate. Results showed golden to very light yellow oils obtained with percentage yield of 1.03 -1.25 respectively (w/w). Analysis of the oils was performed using Gas Chromatography and Gas Chromatography/Mass Spectrophotometry. The leaf oil of Croton pseudopulchellus had germacrene (24.2%),β-phellandrene (17.4%), myrcene (13.4%) and β-caryophyllene (11.4%) as the prominent compounds identified in the oil. The chemical composition of the leaf oil of C. gratissimus was characterized by sabinene (14.6%), β-phellandrene (12.3%), α-phellandrene (10.7%), α-pinene (6.0%) and germacrene D (5.9%). Chemical profiles of the essential oils of Croton species reported in literatures are specific to their geographical location. The oils from C. pseudopulchellus and C. grattisimus were found to have significant antibacterial activities and therefore could be used as natural antimicrobial agents for the treatment of several infectious diseases caused by pathogenic and antibiotic resistant organisms. Chapters 6 and 7 were designed to isolate two bioactive compounds from the stem bark of Lycium inerme and the leaves of Croton grattisimus and were screened for their biological activities against H. influenzae and S. pneumoniae. A qualitative phytochemical screening and bioassay of the plants extracts was carried out. Antimicrobial screening was by broth microdilution and bioautography. Bioassay results showed that compounds with Rf –values between 0.67 to 0.80 were very active against H. influenzae and S. pneumoniae. However, the most active of these compounds was observed at 0.70 for H. influenzae and 0.69 for S. pneumoniae from the dichloromethane extract. Column chromatography, Preparative Thin Layer Chromatography (PTLC) and Sephadex LH20 were used for isolation, sample clean-up and purification of this extract. Two active compounds: a coumarin (7-hydroxy-6-methoxy-coumarin) and two triterpenoids, Ursolic acid (3-oxo-19-hydroxyl-6-methoxylpomolic acid) and Moronic acid (3-oxoolean-12-en-28-oic acid) were isolated from the dichloromethane fraction. The presence of Coumarins and Terpenoids in this herb was observed from the TLC fingerprints. NMR spectroscopic methods were used for the structural elucidation of the active compounds while the GC-MS was used to determine the presence of essential oils from volatile samples obtained from the leaves of C. grattisimus and L. inerme. C. grattisimus extracts possess strong free radicals with scavenging, antimicrobial and antifungal activities; therefore, further studies are needed to determine their efficacies in vivo or clinical usefulness. L. inerme stem bark can therefore be used as a source of alternative medicine or new pharmaceutical and health care product or as a starting material for synthesis of drugs. In chapter 8, general conclusions and perspectives of various parts of the findings were captured. The multi-drug resistance was observed among the emerging respiratory tract bacterial pathogens. It was recommended that measures should be put in place to control the spread of drug resistance in pathogens through improved and standardized laboratory practices, proper and regular surveillance to help guide against the indiscriminate use of antibiotics in empirical treatment. The recognition but cautious use of medicinal plants as alternative sources of therapies and a probable means to solve the emerging resistance problem was recommended. Improved standard of hygiene in hospital settings and the communities is important to prevent the spread of infections. The thesis provides a novel reference document on the genes coding for resistance, antibiograms and phylogenetic profiles of local isolates of H. influenzae and S. pneumoniae as well as the activities, active compounds and toxicity levels of medicinal plants investigated in an endeavour to effectively understand the possible therapeutic, molecular and epidemiological trends in respect of the designated pathogens. , Thesis (Phd) -- Faculty of Health Sciences, 2015
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- Date Issued: 2015-00
IMMUNE RESPONSE TO SPECIFIC MYCOBACTERIUM TUBERCULOSIS ANTIGENS AMONG PARASITE INFECTED SCHOOL CHILDREN IN MTHATHA
- Authors: NTOMBIZODUMO NXASANA
- Date: 2015
- Subjects: IMMUNE RESPONSE, MYCOBACTERIUM TUBERCULOSIS ANTIGENS
- Language: English
- Type: Masters, Msc
- Identifier: http://hdl.handle.net/11260/2369 , vital:41452
- Description: Children from low socio-economic communities in the Eastern Cape Province of South Africa and in South Africa at large are frequently infected by intestinal parasites. The parasites are diverse and complex pathogens that include multi-cellular helminths and single-celled protozoa. Because of this diversity, immunity to parasites is more difficult to sustain. Tuberculosis also, remains a problem in South Africa and worldwide. Infection with Mycobacterium tuberculosis can result either in the disease itself or, more commonly, latent infection. A variety of mechanisms that include both humoral and cell mediated immunity achieve host protection against mycobacterial pathogens. Macrophages and cell-mediated immunity are the primary defence mechanisms against mycobacteria. According to the literature, parasitic infections impair the body’s immune response to tuberculosis, but these diseases are not adequately researched in this province. The extent to which the school children of Mthatha are infected with intestinal parasites and latent tuberculosis, or even how their immune systems respond to these infections have not been investigated. Therefore, the immune response of school children, both of those infected and those not infected with parasites, to specific Mycobacterium tuberculosis antigens was evaluated. The present study used two study design methods: firstly, a descriptive cross-sectional design for the prevalence rates of intestinal parasites and, secondly, a case-control study for comparison of interferon gamma and T-helper 1 and T-helper 2 cytokines in parasite infected and non-parasite infected participants. A total of 137 school children participated in the survey and all were analyzed for parasites. Due to the high cost of the reagent kits, only 75 participants were included in the case-control study. Data collection methods: i) for the prevalence of intestinal parasites, formalin ethyl acetate sedimentation technique was used to process stool specimens, ii) for immune response to Mycobacterium tuberculosis antigens (measurement of interferon gamma for latent tuberculosis),the QuantiFeron TB Gold In-Tube assay was used, and iii) for the quantification of Th1 and Th2 cytokines, the Bio-Plex Pro assay was used. Out of 137 school children analyzed, 66.4% (91/137) were positive for parasites (ova and cysts). The most prevalent parasite was the pathogenic helminth, Ascaris lumbricoides at 21.9% (30/137), followed by Trichuris trichiura at 8.8%. The pathogenic protozoa, Giardia lamblia and Blastocystis hominis were both at 2.9% (4/137). The non-pathogenic protozoa, Entamoeba coli and Endolimax nana had high prevalence rates at 32.1% (44/137) and 29.2% (40/137) respectively. Associations between parasitic infections and sociodemographics showed a significant difference in participants whose parents had a low level of education and those who were unemployed (P = 0.004; P = 0.005 respectively). Out of 75 participants analyzed for tuberculosis, 53.3% (40/75) were positive. In conclusion, the present study demonstrates high prevalence rates of parasitic as well as latent tuberculosis infections in Mthatha. The study also showed that intestinal parasites, especially helminths, interfere with immune responses to TB by down-regulating Th1 response leading to reduced production of interferon gamma, a cytokine that mediates protection against TB.
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