[Frequency of nasal carriers of methicillin-resistant Staphylococcus aureus among health workers in Nicaraguan hospitals]

To determine the frequency of nasal carriers of strains of methicillin-resistant Staphylococcus aureus (MRSA) and the antimicrobial resistance pattern of these strains, obtained from health workers from four hospitals in Nicaragua.A descriptive cross-sectional study was conducted between 1 June 2009 and 30 September 2010. Nasal swabs were taken from health workers who voluntarily agreed to participate in the study, and were cultured on an oxacillin-resistant screening agar base (ORSAB) medium. The S. aureus isolates were identified using ordinary methods, and methicillin resistance was confirmed based on the presence of the mecA gene using the polymerase chain reaction technique. The antimicrobial resistance pattern was detected by the disk diffusion method. Each participant signed an informed consent form before the samples were taken.A total of 569 health workers participated in the study: 208 from one hospital in León, 155 from two hospitals in Chinandega, and 206 from one hospital in Managua. The frequency of nasal MRSA carriers was 9.6% in León, 11.6% in Chinandega, and 6.7% in Managua. The MRSA resistance profile was similar in the four hospitals, and all the strains were sensitive to vancomycin. Of the total MRSA strains isolated, 15% were multi-drug resistant. Erythromycin had the highest percentage of resistance, followed by clindamycin.The results of the study may be regarded as a warning that MRSA strains are circulating among health workers in the participating hospitals. The study also contributes important information regarding the resistance profile of MRSA strains.