Resistance, Minimum Inhibitory and Bactericidal Concentration Profiles of Oral Bacteria from HIV/AIDS Patients in South Western Uganda

Background: The development of drug resistance is a major challenge in the management of microbial infections especially in immune-compromised (HIV/AIDS) patients.

Objective: This was to assess levels of antibacterial resistance; minimum inhibitory and bactericidal profiles of oral bacteria isolated from HIV/ AIDS patients in South Western Uganda and compare their levels with those of the reference organisms (control).

Methods: Bacterial isolates were grown on Mueller Hinton Agar, and biochemical tests were conducted using conventional and analytical profile index 20 sugar panel methods to identify strains. Antibiograms using modified Kirby-Bauer tube dilution and agar well diffusion methods were performed on purified isolates using antibiotic discs for resistance analysis and E-test strips for MIC and MBC analysis. Data were analysed using ANOVA with p< 0.05 considered statistically significant.

Results: All the tested bacteria except Salmonella pullorum and non haemolytic streptococcus showed 50 to 100% resistance to cotrimoxazole and erythromycin demonstrating resistance development in HIV/AIDS patients in rural communities of Uganda against commonly used antibacterials for management of opportunistic infections. Staphylococcus aureus and Escherichia coli were both ˃60% resistant to cotrimoxazole. Pseudomonas aeruginosa and Bacillus cereus were absolutely resistant (100%) to all the antibacterial agents used in this study. MIC and MBC levels for S. aureus when compared with S. aureus ATCC 25293 were highly related showing the level of ineffectiveness of the tested drugs (p=0.235>0.05 (MIC) and p=0.409>0.05 (MBC). High MIC and MBC levels of cotrimoxazole against Pseudomonas aeruginosa were followed by those of Staphylococcus aureus, perhaps associated with neutropenia and granulocyte dysfunction in human infections, necessitating appropriate dosage adjustments. Gentamycin and ceftriaxone had high MIC and MBC levels against E. coli respectively. Further analysis showed significance in ciprofloxacin against all the bacteria in its low MICs.

Conclusion: Bacterial resistance and poor drug efficacy in HIV/AIDS patients in rural communities are a major challenge in Uganda.