Theses And Dissertations

Permanent URI for this collectionhttp://hdl.handle.net/20.500.11837/185

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Browsing Theses And Dissertations by Subject "Escherichia coli -- South Africa -- Eastern Cape"

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    Evaluation of some wastewater treatment facilities in Chris Hani and Amatole district municipalities as potential sources of Escherichia coli in the environment
    (2014) Mazwi, Sinazo Nomathamsanqa
    Access to clean and safe water is essential for the survival of human beings. Pollution of freshwater sources constitutes a major problem hindering access to safe water for drinking and other domestic uses. Wastewater effluent discharges often impact the microbiological qualities of surface waters with its attendant health and environmental problems. This study evaluated the microbiological qualities of the discharged effluents of four selected wastewater treatment plants in Amathole and Chris Hani District Municipalities of the Eastern Cape Province over a twelve-month sampling period. Microbiological analysis (faecal coliform, Escherichia coli and Escherichia coli O157:H7) was done using standard methods and polymerase chain reaction method was used to confirm identities ofbacterial isolates. Presumptive bacteria counts ranged as follows: faecal coliforms 0 to 1.6 × 103 CFU/100 ml, E. coli 0 to 1.4 × 103 CFU/100 ml and E. coli O157:H7 0 to 9.6 × 102 CFU/100 ml. Forty eight percent (305/626) of the presumptive E. coli isolates were confirmed using species-specific uidA gene which code for β-glucuronidase enzyme in E. coli. Antibiotic susceptibility profile of the isolate using a panel of 10 antibiotics shows 100% (150/150) resistance to antibiotics rifampicin and penicillin G while 49.3% (74/150) of the isolates and 46.7% (70/150) were susceptible to streptomycin and cefotaxime respectively. Multiple antibiotic resistance phenotypes (MARP) of the isolates showed resistance to two or more test antibiotics while the calculated multiple antibiotic resistance index (MARI) for the tested isolated is 0.49. The detection of potentially pathogenic E. coli in the final effluents suggestspotential danger to the receiving water bodies where the effluents are discharge. The high MARI valued obtained in this study indicates that the isolates are form environment where the tested antibiotics are being used and may further lead to the spread of multiple antibiotics resistance among other pathogens that may be present in the same environment.
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    Prevalence and antibiogram of some swine associated shiga toxin producing escherichia coli serogroups and salmonella species in Nkonkobe Municipality, Eastern Cape Province, South Africa
    (University of Fort Hare, 2015) Chinwe, Juliana Iwu; Okoh, A I
    Gastrointestinal illnesses have continually become a global public health issue. Exposure to zoonotic food borne pathogens such as Salmonella and diarrhoegenic E. coli either by direct or indirect contact through the consumption of food producing animals is likely an important mode of infection to humans. More so, the use of antibiotics in farm animals similar to those used in humans can select for resistance in bacteria frequently harboured by them. These resistant strains can be passed on to humans through contaminated meat products and water leading to resistant infections with consequences such as prolonged illnesses, treatment failures, and increased morbidity and mortality. In animals, these can lead to reduced productivity. Monitoring the level of resistance among bacteria from animal isolates will help in generating data that could be used to create awareness of their presence in the environment and aid in preventing a potential epidemic in the community. In this study, we investigated the prevalence and antimicrobial resistance profile of Escherichia coli serogroups and Salmonella species in faecal samples collected from pigs in Nkonkobe Municipality in the Eastern Cape Province, South Africa between April – July, 2014. A total of 310 presumptive Shiga toxin producing Escherichia coli (STEC) were confirmed as E. coli spp using polymerase chain reaction (PCR) technique by amplification of the uidA gene, out of which 179 (58%) were confirmed positive. Approximately, serogrougs O157:H7, O145 and O26 made up 24% (n=43), 8% (n=14) and 20% (n=35) of the E. coli population respectively. Only E. coli O26 was positive for stx2 gene in 31% of the isolates harbouring the gene, while the other serogroups were non-pathogenic. Susceptibility of the isolates to 18 antibiotics was carried out in vitro by the standardized agar disc-diffusion method. All the isolates were susceptible to imipenem. Similarly, a relatively high susceptibility was observed in norfloxacin (83-100%), ciprofloxacin (63-100%), gentamycin (77-100%), and chloramphenicol (77-100%). However, all the isolates were resistant to tetracycline and its long acting counterpart oxytetracycline. Resistances observed against other antimicrobials are as follows: ampicillin (84-91%), streptomycin (14-100%), erythromycin (91-100%), ceftazidime (35%). Multiple antimicrobial resistance patterns and indices ranged from 3 to 12 and 0.2 to 0.7 to respectively. Genes encoding resistances to ampicillin (ampC), streptomycin (strA) and tetracycline (tetA) were frequently detected in 50-100%, 22-29% and 40-86% of the resistant isolates respectively. In the other arm of the dissertation, two hundred and fifty eight presumptive isolates of Salmonella were recovered from the faecal samples of pigs. Specific primers targeting serogroups A, B, C1, C2, and D were used to delineate the isolates into different serogroups using PCR. Only serogroup A (n=48) was detected. These isolates were examined for antimicrobial susceptibility by disc diffusion method using 18 antibiotics. The results showed that a large proportion of the isolates were resistant to tetracycline (100%), oxytetracycline (100%), ampicillin (75%), sulphamethoxazole/trimethoprim (75%) and streptomycin (75%). Majority of the isolates exhibited multidrug resistances with the predominant multiple antibiotic resistance (MAR) phenotype being against eleven antibiotics. A high multiple antibiotic resistance (MAR) index in a range of 0.3- 0.6 was observed. The incidence of genes encoding resistance against tetracycline (tetA), streptomycin (stra), and ampicillin (ampC) were 54%, 44% and 61% respectively. These findings reveal that pigs within the Nkonkobe Municipality in the Eastern Cape Province could harbour Shiga toxins and multidrug resistant serogroups of E. coli as well as resistant Salmonella which could be transmitted to humans through the food chain. To ensure public health safety, continuous monitoring and sufficient sanitation in swine industries must be ensured.
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    Studies on the prevalence of Escherichia coli 0157:H7 in raw milk, milking machines, cattle udder and hand swabs collected from selected dairy farms in the Eastern Cape Province, South Africa
    (University of Fort Hare, 2016) Msolo, Luyanda
    Escherichia coli O157:H7 serotype has made its mark over the past decades as one of the common causes of gastrointestinal infections globally; responsible for a number of mortalities and hospilizations. Furthermore, the exploitative use of antimicrobials may support antimicrobial resistance in bacteria which is an alarming health concern in the world of medicine. In this study; the prevalence and antimicrobial susceptibility profiles of Escherichia coli O157:H7 serotype in raw milk and milking utensils, cattle udders and workers hands, in three commercial dairy farms in the Amathole District Municiplality, Eastern Cape Province of South Africa were evaluated. Raw milk samples were collected from bulk storage tanks and swab samples collected from milking machines, cattle udders and worker’s hands fortnightly over a six month period (June to November 2014). Spread plate technique was used for the enumeration and isolation of E. coli O157:H7 from the samples using sorbitol MacConkey agar plates supplemented with cefixime and potassium tellurite. A serological confirmation of the presumptive E. coli O157:H7 isolates was done using the O157 Latex agglutination test kit. A total of 252 presumptive E. coli O157:H7 isolates obtained were further subjected to polymerase chain reaction (PCR) amplification of rfbEO157 and fliCH7 genes, out of which 27(11 percent) of the isolates were confirmed positive E. coli O157:H7. The phenotypic antibiotic susceptibility profiles revealed that the bacterial isolates were susceptible to the antimicrobials in the following proportions: amikacin (70 percent), Doxycline (66 percent), cefotaxime (66 percent) and gentamycin (48 percent). Nonetheless; multidrug resistance was obtained with as high as 85 and 81 percent of the isolates resistant against penicillin G and tetracycline antibiotics respectively. Our findings also showed about 70 percent of the isolates showed resistance against erythromycin, while 52 percent of the isolates were resistant against streptomycin. These findings reveal that; the three selected dairy farms in the Eastern Cape Province, South Africa are reservoirs of the pathogenic and antimicrobial resistant E. coli O157:H7 serotype which is a cause for concern to public and environmental health.