The sub-therapeutic use of antibiotics for growth promotion in food animal production, has engendered substantial debate on the dissemination of antibiotic resistance via the food chain, specifically, the probability of antibiotic use in food production creating a reservoir of resistant bacteria and/or resistance genes that may spread to humans thereby limiting the therapeutic value of antimicrobial drugs. In the absence of any surveillance programme on food-borne bacteria in South Africa, this study focussed on Campylobacter spp. in poultry and encompassed a literature review on the prevailing debate on the dissemination of antibiotic resistance via the food chain, a phenotypic observational study on the prevalence and antibiotic resistance profiles of Campylobacter spp. isolated within and across different poultry farming systems and a genotypic component that covered identification methods, plasmid profile determination and strain typing. Identification methods for Campylobacter spp., viz, biochemical tests and matrix assisted laser desorption ionization- time of flight (MALDI-TOF) mass spectrometry was compared to the PCR which is considered the gold standard as a molecular method of identification. The MALDI-TOF was shown to be superior to the biochemical tests for the identification of C. coli but equivalent to the biochemical tests for C. jejuni. Of the 363 samples collected in total, the frequency of thermophilic Campylobacter was 68 % in rural farms (or informally reared poultry), 47 % in both commercial free-range and industrial broilers and the highest in industrial layers at 94 %. Antibiotic resistance analysis showed that isolates from the rural farming systems were significantly (P < 0.01) more susceptible to ciprofloxacin, tetracycline and erythromycin when compared to the other farming systems. Significant (P < 0.001) antibiotic resistance differences were detected between broilers (5 - 8 week lifespan), and layers (36 - 52 week lifespan) for gentamicin, ciprofioxacin and tetracycline. Plasmids were fonnd be harboured by isolates in all the farming systems; in 84 % of isolates from free-range broilers, 77 % of isolates from industrial broilers, 83 % of isolates from industrial layer hens and 75 % of isolates from the rural farming system. The PFGE genotyping of 42 Campylobacter isolates generated 39 SmaI types. Substantial and substantive genetic diversity was observed between and within farming systems. The lack of correlations amongst the parameters within and between farming systems attested to the diversity and complexity of phenotypes and genotypes and indicated de novo evolution in response to antibiotic selection pressure and animal husbandry practices. / Thesis (Ph.D.)-University of KwaZulu-Natal, Westville, 2013.

Thesis(M.S.)--Auburn University, 2006. / Abstract. Vita. Includes bibliographic references.

Thesis--Auburn University, 2008. / Abstract. Vita. Includes bibliographical references (p. 88-101).

Thesis (M.S.)--Michigan State University. Dept. of Fisheries and Wildlife, 2008. / Title from PDF t.p. (viewed on July 29, 2009) Includes bibliographical references (p. 64-73). Also issued in print.

Thesis (M.D.)--Universitet Københavns, 2006. / Includes bibliographical references.

Approximately 2-4 billion cases of infectious diarrhoea occur every year, with the highest numbers recorded in sub-Saharan Africa. It remains the most common public health issue among children in developing nations. The purpose of this research was to unfold the prevalence of diarrhoeagenic E. coli and Campylobacter pathotypes as well as elucidate their antibiogram characteristics in diarrhoeal stool samples collected in some medical facilities in Eastern Cape Province, South Africa. Two hundred stool samples were collected from both inpatients and outpatients from male and females of all age groups attending selected medical facilities in the study area. Isolation and characterization of both organisms were done using culture based and molecular methods. Antibiotic susceptibility patterns of identified isolates were determined against a panel of 12 antimicrobial agents. One hundred and twenty presumptive E. coli isolates and 42 presumptive isolates of Campylobacter spp. Were isolated. Eighty-two percent (82 percent) of the presumptive E. coli isolates were confirmed as E. coli while 46.3 percent belonged to Campylobacter spp. Pathotyping of the diarrhoeagenic E. coli isolates by Polymerase chain reaction (PCR) showed the following prevalences: DAEC 43 (32 percent), EHEC 18 (17 percent), EIEC 11 (10 percent) and EPEC 18 (17 percent). EAEC and ETEC were not detected, while for Campylobacter spp. 37 (88 percent) were C. jejuni, and C. coli was not detected. A total of 12 (32.4 percent) of the confirmed Campylobacter jejuni isolates were found to possess the fliM gene, 9 (24.3 percent) possessed the flhA gene and only 6 (16.2 percent) harboured the gene flgE2. None were positive for the flaA, flab and flhB genes.The antibiotic resistance patterns observed among the E. coli isolates were high against ampicillin (98.1 percent), chloramphenicol (94.3 percent) and tetracycline (90.6 percent). For Campylobacter spp., resistance observed were: chloramphenicol (91.6 percent), tetracycline (25.2 percent), erythromycin (49.6 percent) and gentamycin (56.4 percent). A lesser resistance against imipenem (35.9 percent) and quinolone (ciprofloxacin) (45.5 percent) were exhibited by the E.coli isolates. 10.8 percent and 20.3 percent of the Campylobacter isolates were resistant to imipenem and ciprofloxacin respectively. The presence of chloramphenicol (CatA1) and tetracycline (tetA) resistance genes were detected in 94 percent and 89 percent of E. coli isolates respectively while 98 percent of Campylobacter spp. Harboured the catA1 resistance gene. It could be deduced from this study that E. coli and Campylobacter spp. are predomiant enteric pathogens as the etiologic agents of diarrhoea in the study community, and that their antimicrobial resistance is high in the study location. The need to develop strategies to prevent infection and control resistant organisms is evident.

Thesis--Auburn University, 2009. / Abstract. Vita. Includes bibliographic references.

Thesis--Auburn University, 2008. / Abstract. Vita. Includes bibliographical references (p. 67-77).

No description available.

Aerotolerance of Campylobacter jejuni ATCC 29428 and one of its aerotolerant mutants (strain MC711-01) was measured at 37°C and 42°C. The aerotolerance of C. jejuni was higher at 42°C than at 37°C. Three different lots of Gibco dehydrated Brucella broth were used to prepare Brucella agar. The agar media were then tested to see if they differed in their ability to support growth of C. jejuni. However, only slight differences in viable counts of C. jejuni were obtained between lots. Ageing of dehydrated Brucella medium for 2½ months and hydrated Brucella medium for 1½ months greatly affected the growth of C. jejuni and decreased its aerotolerance. This is probably due to the deterioration of the sodium bisulfite in Brucella medium during storage, because addition of 0.01% sodium bisulfite (the same amount as contained in the Brucella medium) to the aged medium (dehydrated or hydrated form) restored the ability of the medium to support growth of C. jejuni under various O₂ levels equivalent to or even better than that obtained with fresh Brucella medium. Moreover, when Brucella agar was prepared from the individual chemical and peptone components, only the medium containing the 0.01% bisulfite yielded colony counts of C. jejuni similar to that obtained on fresh commercial Brucella medium. When sodium bisulfite was omitted, viable counts and aerotolerance were decreased. / Master of Science