Antimicrobial susceptibility pattern and plasmid profiles of bacterial isolates from four hospitals in Jos Metropolis

Abstract

Antimicrobial resistance poses a serious threat to healthcare, leading to protracted illness, increased mortality risk, and spread of infection. The World Health Organization recommends continuous surveillance of antibiotics for resistance. This study aimed to investigate the pattern, scale, and possible mechanisms of resistance of common bacterial pathogens. A total of 174 bacterial isolates from biological samples (mainly urine and stool) were collected from four hospitals in Jos metropolis. The organisms were grown in selective media and characterized by colonial morphologies, Gram stain and biochemical tests. Antimicrobial sensitivity tests were performed using the disc diffusion method. Plasmid curing and β-lactamase test was conducted on multidrug resistant isolates using ethidium bromide as the curing agent in addition to gel electrophoresis of cured plasmids. Out of 174 isolates, 74 (42.5%) were E. coli, 48 (27.6%) S. aureus, 26 (14.9%) Salmonella species while 26 (14.9%) were Streptococcus species. Antimicrobial sensitivity test with 10 common antibiotics revealed 77 resistant phenotypes, with oxacillin and sulfamethoxazole/trimethoprim common in 55 (71.4%) and 60 (79%) of the phenotypes respectively, while oxacillin resistance had the highest (96-98%) occurrence. The activity of the antibiotics against the isolates revealed that gentamicin is the most active across all four facilities while oxacillin exhibited the lowest activity. The study revealed that Multiple-Antibiotic Resistance indices of 147 (84.5%) of isolates were greater than 0.2 while 34 (92%) of 37 selected isolates had β-lactamase enzymes. Treatment of the selected group with ethidium bromide revealed 13.5% cure rate while, gel electrophoresis revealed the presence of plasmids in 19 (51.3%) of the 37 selected isolates. This study shows that a high prevalence of multiple antibiotic resistance exists among common bacterial pathogens and is mediated by both chromosome and plasmids. The susceptibility profiles could be used to promote responsible antibiotic prescribing in these facilities.

Keywords

• Antimicrobial susceptibility
• Plasmid profile
• Bacterial isolates
• Jos metropolis