American Journal of Life Sciences 2014; 2(4): 200-204 Published online August 10, 2014 (http://www.sciencepublishinggroup.com/j/ajls) doi: 10.11648/j.ajls.20140204.12 ISSN: 2328-5702 (Print); ISSN: 2328-5737 (Online) Asymptomatic carriage of plasmid-mediated multidrug- resistant Staphylococcus aureus in nasal tracts of persons in a semi-urban area of Nigeria Jonathan Osariemen Isibor, Ehima Otabor Department of Microbiology, Faculty of Natural Sciences, Ambrose Alli University, Ekpoma, Edo State, Nigeria Email address: joe_isibor@yahoo.com (Isibor J. O.) To cite this article: Jonathan Osariemen Isibor, Ehima Otabor. Asymptomatic Carriage of Plasmid-Mediated Multidrug-Resistant Staphylococcus aureus in Nasal Tracts of Persons in a Semi-Urban Area of Nigeria. American Journal of Life Sciences. Vol. 2, No. 4, 2014, pp. 200-204. doi: 10.11648/j.ajls.20140204.12 Abstract: Staphylococcus aureus remains one of the most important opportunistic bacterial pathogens of man and strains resistant to available drug classes have become more and more prevalent in clinical and community settings. The aim of this study was to determine the nasal carriage rates of multidrug – resistant (MDR) Staph aureus in food vendors and hospital workers in Ekpoma, Nigeria, and to assess whether resistance was plasmid – mediated. With the use of sterile swab sticks (Sterilin, UK), one hundred nasal swabs were obtained from consenting volunteers. Each swab was streaked on mannitol salt agar (Difco, Detroit MI) and incubated at 37 0 C for 24hrs. Colonies growing on medium were Gram – stained and tested for catalase, coagulase and mannitol fermentation. Antibiotic susceptibility tests were performed using the Kirby-Bauer disc diffusion technique, and results were interpreted using the Clinical and Laboratory Standard Institute’s guidelines. Results showed that 32 (32%) of the 100 specimens screened yielded Staph aureus, with 18 (36%) and 14 (28%) of the isolates recovered from hospital workers and food vendors, respectively. The prevalence rate in males (40%) compared with females (24%) was not statistically significant (P>0.05), using Student’s t-test analysis. All the Staph aureus isolates were susceptible to Augmentin. The highest resistance rates of 65.6%, 59.3% and 50.0% were recorded for Amoxycillin, Ofloxacin and Oxacillin respectively, while low resistance rates were recorded for Gentamicin (9.38%) and Cefuroxime (15.6%). Of the 17 (53%) MDR isolates of Staph aureus, only 4 (23.5%) remained MDR after curing with 0.1mg/ml acridine orange solution. Observance of personal hygiene can reduce the level of contamination or infection of carriers thereby reducing the risk of infection for others in the community, while rational use of antibiotics by health professionals and end users could help to curb the rising trend of antibiotic resistance within the community. Keywords: Asymptomatic Carriage, Nasal Tract, Multidrug Resistance, Staphylococcus aureus, Plasmids, Ekpoma 1. Introduction Staphylococcus species are among the most disease – causing bacteria and a leading cause of community and hospital acquired bacterial infections [1], ranging from minor skin lesions such as boils and furuncles, to severe life threatening, infections such as pneumonia and urinary tract infections and also deep seated infections such as osteomyelitis and endocarditis [2]. Its pathogenic potential involves two mechanisms – tissue invasion and toxin production. Staph aureus colonizes various anatomical sites of the average healthy person including the nares, skin, vagina and gastrointestinal tract [1], and in particular, nasal carriage of the organism has been reported to be linked to most community and hospital associated infections [3-7]. Contaminated surfaces and hands can contribute to the transmission of Staph aureus to the anterior nares; the latter serving as endogenous reservoirs from where clinical infections can occur within the colonized individual as well as within the community [8,9]. The development of antibiotic resistance by strains of Staph aureus has risen to an embarrassing proportion in medical care facilities just as multidrug resistant (MDR) strains of the organism have been reported with increasing frequency worldwide [10]. Staph aureus has a remarkable capability of evolving different mechanisms of resistance to most antimicrobial agents [11] including the acquisition