Browsing by Author "Keddy, Karen H"

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    Characterisation of STEC and other diarrheic E. coli isolated on CHROMagar™STEC at a tertiary referral hospital, Cape Town
    (BioMed Central, 2018-06-08) Kalule, John B; Keddy, Karen H; Nicol, Mark P
    Abstract Background Shiga toxin producing E. coli (STEC) is an emerging zoonotic pathogen that can cause acute renal failure, especially in children. Clinical microbiology laboratories may fail to detect STEC and other diarrhoeic E. coli unless purposive rigorous screening procedures are followed using appropriate diagnostic technology; CHROMagar™STEC has rarely been used for isolation of African diarrhoeic E. coli hence characteristics of isolates on this medium are not yet fully understood. This study aimed to determine the prevalence and characteristics of STEC and other diarrhoeic E. coli isolated on CHROMagar™STEC from stool samples submitted to the microbiology laboratory of a South African public sector tertiary care hospital. Results In total, 733 stool samples were tested. Of these, 4.5% (33/733) possessed diarrhoeic E. coli. Of the diarrheic E. coli, 5/33 (15.2%) were STEC, 15/33 (45.5%) EAggEC, 6/33 (18.2%) atypical EPEC, 5/33 (15.2%) typical EPEC, and 1/33 (3%) DAEC. None of the STEC isolates had been identified by routine testing (based on using sorbitol media to test for E. coli O157: H7 strains and not the other STEC) in the laboratory. Of the 33 strains, 55% (95% CI = 40.8–72.7) showed resistance to ampicillin. Conclusions CHROMagar™STEC enabled detection of tellurite - resistant diarrhoeic E. coli that would be missed using routine methods. Further studies are needed to determine the proportion and characteristics of those which might have been missed using this approach.
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    One Health-One City; the extent of Shiga-toxin producing Escherichia coli in Cape Town
    (2017) Kalule, John Bosco; Nicol, Mark P; Keddy, Karen H
    The estimated global burden of STEC (Shiga toxin producing Escherichia coli) is 2,481,511 illnesses, 269 deaths, and 26,827 DALYs with 48% of these being foodborne. This thesis provides information on STEC diagnostic strategy, undetected STEC in a tertiary referral hospital in Cape Town, and the virulence and antimicrobial resistance properties of tellurite resistant diarrheic E. coli isolated on CHROMagar(TM)STEC (CHROMagar Microbiology, Paris, France). Deploying the One - Health surveillance approach to study selected diarrheic bacterial pathogens in an informal settlement setting, this study sheds light on the extent of bacterial foodborne pathogens in human and non-human sources.
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    Prevalence and antibiotic susceptibility patterns of enteric bacterial pathogens in human and non-human sources in an urban informal settlement in Cape Town, South Africa
    (2019-11-06) Kalule, John B; Smith, Anthony M; Vulindhlu, Mjikisile; Tau, Nomsa P; Nicol, Mark P; Keddy, Karen H; Robberts, Lourens
    Abstract Background In light of rampant childhood diarrhoea, this study investigated bacterial pathogens from human and non-human sources in an urban informal settlement. Meat from informal abattoirs (n = 85), river water (n = 64), and diarrheic stool (n = 66) were collected between September 2015 and May 2016. A duplex real-time PCR, gel-based PCR, and CHROMagar™STEC were used to screen Tryptic Soy Broth (TSB) for diarrheic E. coli. Standard methods were used to screen for other selected food and waterborne bacterial pathogens. Results Pathogens isolated from stool, meat, and surface water included Salmonella enterica (6, 5, 0%), Plesiomonas shigelloides (9, 0, 17%), Aeromonas sobria (3, 3, 0%), Campylobacter jejuni (5, 5, 0%), Shigella flexneri (17, 5, 0%), Vibrio vulnificus (0, 0, 9%), and diarrheic E. coli (21, 3, 7%) respectively. All the isolates were resistant to trimethoprim–sulphamethoxazole. Conclusions There was a high burden of drug resistant diarrheal pathogens in the stool, surface water and meat from informal slaughter. Integrated control measures are needed to ensure food safety and to prevent the spread of drug resistant pathogens in similar settings.