Biofilm production and antibiotic susceptibility profile of <i>Escherichia coli</i> isolates from HIV and AIDS patients in the Limpopo Province

Abstract

In the present study, Escherichia coli strains were isolated from water, stool, sputum and urine samples from HIV and AIDS patients attending treatment centers in the Limpopo Province, using standard microbiological procedures and identified by polymerase chain reaction (PCR). Biofilm assay was performed using the Congo red agar and the microtiter plate methods. Beta-lactamase production was tested using the iodometric method, while the antibiotic susceptibility profiles of the organisms were determined by the disc diffusion method. Of the 139 isolates tested, 58 (42%) were biofilm producers with 22 (16%) of these being strong biofilm producers. Antibiotic resistance was common but kanamycin, meropenem and lomefloxacin were the most active with 6.6, 5.8 and 4.3% resistance rates respectively. The rate of biofilm formation was higher among E. coli isolates from water (55.5% p-value=0.011). Antibiotic resistance was higher among biofilm producers compared to non producers particularly for penicillin (93.1%) and cefipime (50.0%). Lomefloxacin appeared to be the most active antibiotic against the biofilm producing strains with 1.7% resistance among the biofilm producers compared to 6.3% among the non-biofilm producers. Beta-lactamase production was higher among isolates from urine samples. This study suggests that E. coli strains that produce biofilm are common in water and urine samples. However, further studies are needed to determine the potential role of water in the production of urinary tract infections (UTIs) in HIV patients.

Keywords: Co-infections, HIV and AIDS, epidemiology, Venda, South Africa