Methicillin-resistant Staphylococcus aureus (MRSA) Isolated from Colombian Foods

Abstract

Methicillin-resistant Staphylococcus aureus (MRSA) was identified as a nosocomial pathogen in the 1960s and it is associated with serious community-acquired and nosocomial diseases, particularly in immuno- compromised patients. S. aureus also causes food poisoning and is the most important food-borne disease in Latin America. In Colombia, the Community acquired (CA-MRSA) increased by 4.4% between 2001 and 2006. However, the transmission of MRSA through food has not been well researched; its prevalence is unknown as is the risk of consumer exposure. It is important to determine the role of food in transmission of antibiotic-resistant bacteria, taking into account that the prevalence of MRSA varies according to geographical location. The aim of this study was to determine the prevalence of MRSA in Colombian foods and to typify isolated strains by detecting antimicrobial resistance, clonal groups and Toxin A gene. Resistance of 149 S. aureus strains isolated from food was determined by disk diffusion with oxacillin (1μg) and cefoxitin (30μg), Antimicrobial Susceptibility Test (AST) and mecA gene amplification. Positive strains were genotyped using pulsed field electrophoresis (PFGE). 5 (3.35%) of the 149 strains resistant to oxacillin and cefoxitin, were positive to mecA gene, indicating the presence of the SCC cassette. The electrophoretic pattern obtained by PFGE for these strains revealed that 4 (80%) of the 5 strains belong to the Chilean clone, with 100% genetic similarity; this clone has been associated with 65% of infections associated with health care. Furthermore, none of the 5 strains were positive to Toxin A gene. This is the first evidence of the presence of MRSA in food in Colombia. It is http://ccaasmag.org/BIO necessary to continue this research by extending the sampling and collecting enough information to carry out risk analysis of the danger.