Background: The aim of this study was to characterize the resistance patterns and resistance gene profiles of selected Escherichia coli, Staphylococcus aureus and Pseudomonas isolates from HIV seropositive patients in Akure, Southwestern Nigeria between April to October, 2012.
Methods: Isolates from throat, skin and rectal swab cultures from HIV seropositive patients at the State Specialist Hospital, Akure were identified using standard microbiological procedures. A total of 96 isolates of the four organisms were subjected to antibiotic susceptibility testing by the disk diffusion method. Isolates from HIV seronegative individuals were also included as controls. A total of 43 isolates were subjected to plasmid profiling and screened for the presence of virulence and resistance genes by PCR.
Findings: The bacterial isolates cultured from HIV seropositive patients exhibited higher levels of multiple antibiotic resistance as compared to the isolates obtained from HIV seronegative individuals. Twenty eight (60.9%) of the 43 isolates were found to be resistant to at least six different classes of antibiotics. None of the 43 isolates had any plasmid. Results of the ERIC-PCR showed ten (10) gene band patterns for the two Pseudomonas species, four band patterns for S. aureus and two patterns for E. coli, suggesting a diversity of strains among the isolates. Four of the 18 Pseudomonas isolates carried aadA gene while eight had the blaPSE gene. Only two isolates out of the eight of S. aureus isolates that were tested carried the mecA gene. The MAR index of the tested isolates revealed that 93.5% of the isolates from HIV seropositive individuals were above 0.2, suggesting an antibiotic pressurized community.
Conclusion: The bacterial isolates that were cultured from our HIV seropositive study cohort did not reveal presence of any plasmid, but showed high levels of multi-drug resistance and multiple gene band patterns. The presence of multiresistant bacterial strains on the body surface of immune-compromised HIV sero-positive subjects would significantly increase the risk of superimposed opportunistic infections which may be less susceptible to antibiotic treatment. These results suggest the need for further investigation into the mechanisms of drug resistance among immune-compromised individuals.