Isolation of vanconycin resistant Staphylococcus aureus from the wounds of hospital patients in Uyo, Akwa Ibom State, Nigeria

Staphylococcus aureus is a very important human pathogen that generates a number of human infections. Isolation of vancomycin-resistant Staphylococcus aureus (VRSA) was carried out from wound samples of patients attending University of Uyo Teaching Hospital, Akwa Ibom state, Nigeria. A total of 45 wound samples from 15 patients were collected aseptically in triplicate, using sterile cotton swabs moistened in sterile normal saline. Microbiological analysis and susceptibility to vancomycin, including minimum inhibitory and minimum bactericidal concentrations (MIC and MBC), were carried out using standard methodologies. A total of 15 isolates were obtained and these showed varying MIC and MBC patterns. Out of the 15 S. aureus isolated, only one isolate had an MIC of approximately 4 µg/ml, while twelve isolates gave MIC values that ranged from 15.62 µg/ml to 250 µg/ml. The remaining 2 isolates gave MIC values that were ≥ 500 µg/ml. These 2 isolates exhibited alpha haemolysis on blood agar, unlike the others that were beta haemolytic. The results of the MBC also showed variations amongst the isolates. A total of 10 isolates gave MBC values that ranged from 62.5 µg/ml to 500 µg/ml, while the remaining 5 isolates gave MBC values that were ≥ 500 µg/ml. The high MIC and MBC values obtained showed that vancomycin-resistant Staphylococcus aureus is increasing at an alarming rate, and this accounts for the gradual decline in the effectiveness associated with the use of vancomycin. Given the widespread prevalence of VRSA, there is a need for newer therapeutics that can reverse this surge.