Prevalence and Multi Drug Resistance Patterns of Nasal Carriage Staphylococcus aureus in Dairy Workers in and around Asella Town, Arsi Zone, South Eastern Ethiopia

Abstract

A cross-sectional study was carried out from November 2012 - May 2013 to estimate the prevalence and multi drug resistance patterns of nasal carriage Staphylococcus aureus and its putative risk factors among dairy farm workers in and around Asella town, Arsi Zone, South Eastern Ethiopia. A total of 96 nasal swab samples were collected from volunteer dairy farm workers using convenient sampling method. The collected samples were subjected to bacteriological examinations, using different techniques according to standard procedures, for isolation and identification of Staphylococcus aureus. Staphylococcus aureus isolates were identified from 39.58% (38/96) of nasal swab samples. Multivariate logistic regression analysis of the effect of different risk factors on the prevalence of nasal carriage Staphylococcus aureus revealed that; male individuals (OR = 5.773, 95%CI: 1.727, 19.296) and poor milking hygiene scores (OR= 4.805, 95%CI: 1.651, 13.985) were more likely to be colonized with nasal carriage S. aureus than their counter parts. The isolates of Staphylococcus aureus were tested for antimicrobial susceptibility test by disc diffusion method. Susceptibility to methicillin was phenotypically determined based on sensitivity of isolates to cefoxitin and oxacillin. The highest rate of susceptibility was to vancomycin (97.4%) followed by gentamycin (96.2%), chloramphenicol (85.3%), clindamycin (82.6%), erythromycin (71.5%) and streptomycin (69.6%). Whereas, the highest rate of resistance among the isolates was against penicillin G (83.7%) followed by ampicillin (71.7%), cefoxitin (60.8%), oxacillin (56.1%), tetracycline (54.9%), amoxicillin-clavulinic acid (42.4%) and trimethoprim-sulfamethoxazole (39.5%). Of the total nasal carriage Staphylococcus aureus isolates, 60.8% were MRSA and 55.3% were MDRSA. The presence of multidrug resistant isolates in nasal swabs among dairy farm workers demonstrates the importance of the choice and appropriate use of antimicrobial agents. Regular antimicrobial sensitivity testing and recognizing the appropriate pattern of antibacterial resistance could pave the way for optimized antibiotic prescription in order to prevent resistance to newly developed antibiotics.

Keywords: Assella, dairy workers, multidrug resistance, nasal carriage Staphylococcus aureus, prevalence.