Browsing by Author "Whitelaw, A"

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    National sentinel site surveillance for antimicrobial resistance in Klebsiella pneumonia isolates in South Africa 2010-2012
    (Health and Medical Publishing Group, 2014) Perovic, O; Singh-Moodley, A; Duse, A; Bamford, C; Elliott, G; Swe Swe-Han, K; Kularatne, R; Lowman, W; Whitelaw, A; Nana, T; Wadula, J; Lekalakala, Ruth; Saif, A; De-Smidt, M F; Marais, A
    BACKROUND: The increasing rates of antimicrobial resistance observed in the nosocomial pathogen Klebsiella pneumoniae are of major public health concern worldwide. OBJECTIVES: To describe the antibiotic susceptibility profiles of K. pneumoniae isolates from bacteraemic patients submitted by sentinel laboratories in five regions of South Africa from mid-2010 to mid-2012. Molecular methods were used to detect the most commonly found extended-spectrum beta-lactamase (ESBL) and carbapenemase resistance genes. METHODS: Thirteen academic centres serving the public healthcare sector in Gauteng, KwaZulu-Natal, Free State, Limpopo and Western Cape provinces submitted K. pneumoniae isolates from patients with bloodstream infections. Vitek 2 and MicroScan instruments were used for organism identification and susceptibility testing. Multiplex polymerase chain reactions (PCRs) were used to detect blaCTX-M, blaSHV and blaTEM genes in a proportion of the ESBL isolates. All isolates exhibiting reduced susceptibility to carbapenems were PCR tested for blaKPC and blaNDM-1 resistance genes. RESULTS: Overall, 68.3% of the 2 774 isolates were ESBL-positive, showing resistance to cefotaxime, ceftazidime and cefepime. Furthermore, 46.5% of all isolates were resistant to ciprofloxacin and 33.1% to piperacillin-tazobactam. The major ESBL genes were abundantly present in the sample analysed. Most isolates (95.5%) were susceptible to the carbapenems tested, and no isolates were positive for blaKPC or blaNDM1 There was a trend towards a decrease in susceptibility to most antibiotics. CONCLUSION: The high proportion of ESBL-producing K. pneumoniae isolates observed, and the prevalence of ESBL genes, are of great concern. Our findings represent a baseline for further surveillance in SA, and can be used for policy and treatment decisions.
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    Prevalence of bacterial contamination of powdered infant feeds in a hospital enviroment
    (2007) Marino, L V; Goddard, E; Whitelaw, A; Workman, L
    Background. The study arose as part of a best-practice nutrition model regarding the introduction of ready-to-use (RTU) infant feeds in place of powdered infant feeds (PIFs) as a standard formula for infants under the age of 1 year who are unable to be breastfed. Internationally and locally there is grave concern regarding the safety and efficacy of mixing PIFs, especially in a hospital setting, and the resultant bacterial contamination causing enteric infections, especially in premature, immunocompromised and sick infants. Objective. To evaluate the prevalence of bacterial contamination of PIFs given to infants at Red Cross War Memorial Children’s Hospital, Cape Town. Methods. Quantitative levels of bacterial contamination were determined and were expressed as colony-forming units (CFUs) per millilitre of sample. Aliquots of milk were inoculated onto agar, and the milk samples were then incubated at 25o C overnight (N = 10), 30o C overnight (N = 48) and 30o C for 6 hours (N = 34). Post-incubation milk samples were cultured again. Contamination was defined as any positive culture before administration (i.e. pre incubation) or > 102 CFU/ ml after administration (i.e. post incubation). Results. Fifty samples of PIFs (N = 82) were contaminated pre incubation, with 25/82 samples (30.4%) being heavily contaminated (≥ 104 CFU/ml). Post incubation, 43/92 samples (46.7%) were contaminated with > 102 CFU/ml. The acidified PIFs appeared to have some bactericidal effect against some of the organisms, but not all. Conclusions. RTU infant feeds are sterile and are recommended for use in all hospitalised infants. The results of this study indicate that even when milk is prepared in a controlled environment there is significant bacterial contamination of PIFs post production. As RTU feeds are now readily available in South Africa every attempt should be made to use a sterile RTU system for hospitalised infants