RESUMO
Aims@#Although several major food poisoning outbreaks caused by Staphylococcus aureus have been reported, monitoring of this pathogen is often neglected. The objectives of this study were to assess the contamination level of S. aureus and characterize the S. aureus isolated in ready-to-eat (RTE), food handlers, food contact surfaces, and table cleaning cloths (TCC). @*Methodology and results@#A total of 150 RTE foods, 59 food contact surfaces (FCS) and 34 table cleaning cloths (TCC) from food premises were examined. The contamination level of S. aureus in RTE foods was at acceptable level. However, more than 10% of the FCS and TCC were contaminated with high levels of S. aureus (>1.0 Log CFU/cm2, >2.7 Log CFU/piece). Eighty-one isolated S. aureus including those isolated from hands of food handlers were further characterized by antimicrobial susceptibility testing, virulotyping and PFGE. Out of 81 isolates, only three were multidrug resistant. More than 96% (n = 78) of the S. aureus harboured at least one virulence gene. Almost half of the isolates carried at least one staphylococcal enterotoxin in which SEC was the most common enterotoxin detected. @*Conclusion, significance and impact of study@#The PFGE analysis showed that the S. aureus could be disseminated via the FCS, TCC and the hands of food handlers. Therefore, this study reiterates the importance of proper hand washing, sanitation of FCS and TCC, as well as continuous monitoring on S. aureus in food and the food handlers.
RESUMO
Salmonella infections remain a major public health problem in developing countries. The occurrence of infections caused by antimicrobial-resistant Salmonella has been on the rise complicating the available therapeutic options. The study aimed to determine the antibiograms and genotypes of prevalent Salmonella serotypes. A retrospective study involving 80 stool and extra-intestinal Salmonella strains collected over a 18-month period [January 2005-June 2006] from a tertiary hospital in Penang, Malaysia was conducted. Isolates were examined for resistance to 14 antimicrobial drugs and the clonality of the strains was determined by PFGE. Twenty-one serotypes were identified, the most common being S. enteritidis [42.5%] followed by S. corvallis [11.25%] and S. braenderup [11.25%]. S. enteritidis was significantly more common amongst the extra-intestinal isolates compared to stool isolates [74.2% versus 22.4%, p < 0.0001]. Overall, the highest resistance was observed for tetracycline [66.3%], sulphonamides [56.3%], streptomycin [32.5%], trimethoprim [28.8%] and nalidixic acid [27.5%]. Amongst the 31 invasive extra-intestinal isolates, resistance towards therapeutically relevant antibiotics was as follows: co-trimoxazole [38.7%], ampicillin [29%] and ceftriaxone [3.2%]. Although there was no detectable resistance towards chloramphenicol and ciprofloxacin, 29% strains showed nalidixic acid resistance. About 41% of the 80 isolates were multidrug-resistant. PFGE subtyped the 78 Salmonella isolates to 33 distinct XbaI-pulsotypes. Isolates within the serotypes S. enteritidis, S. corvallis, S. branderup and S. fasta were more homogeneous while S. typhi and S. weltervden were genetically more diverse. The high percentage of multidrug-resistant Salmonella strains is worrying and is of public health concern. PFGE was a useful and discriminative method for assessing the genetic diversity of Salmonellae