Linezolid and Methicillin Resistances in S. aureus Isolated from the Anterior Nares of Apparently Healthy Undergraduates of the Niger Delta University, Nigeria

Background: The carriage of Staphylococcus aureus in the anterior nares of subjects in the study environment has not been carried out before and this study is thus a reference study against which future studies can be compared. The isolates obtained were also tested against frequently used antibiotics as well as linezolid, an antibiotic which is of considerable importance in the treatment of Methicillin Resistant Staphylococcus aureus (MRSA).

Methods: A total of 400 nasal swabs were collected from anterior nares of apparently healthy subjects aseptically using a sterile swab sticks. The antibiotic susceptibilities of isolates of S. aureus obtained against eight different antibiotics including Linezolid were determined using the disc-plate method.

Results: The results showed that 91 (22.8%) of the subjects tested are nasal carriers of S. aureus. The incidences of resistance observed with each of the antibiotics tested were as follow: Erythromycin 83(91.2%), Tetracycline 79(86.8%), Co-trimoxazole 78(86.8%), Cefoxitin 77(84.6%), Linezolid 72(79.1%), Ciprofloxacin 70(76.9%), Augmentin 49(53.8%) and Gentamycin 39 (42.9%).

Conclusion: Treatment of S. aureus infections within the study environment should be based on the results of in vitro susceptibility testing of the isolates. Gentamicin promises to be the best antibiotic for the treatment of disorders associated with Staphylococci in the study area. This is of special importance in an environment within which a very substantial proportion of the isolates are resistant to methicillin and linezolid.