Sensitivity and Resistance Patterns of Gram-Negative Uropathogens Isolated from the Urine of Patients with Upper/Lower Urinary Obstruction in Nigeria

Background: Urinary tract infection is a cause of significant morbidity and potential mortality in patients. Urine microscopy culture and sensitivity enable the isolation of the incriminating microbes. The sensitivity and resistance of the various microorganisms are invaluable in the effective management of UTIs and the associated adverse consequences. Gram-negative organisms are the usual pathogens responsible for most UTIs. The abuse of antibiotics can increase the prevalence of antimicrobial resistance. This leads to an increased cost of treatment, as more expensive higher-end antibiotics may become indicated. There is also the risk of spreading multidrug-resistant infections to the community.

Aims: To evaluate the sensitivity and resistance patterns of commonly available antibiotics to uropathogens in the positive urine culture of patients who presented with upper and lower urinary obstruction.

Methods: This retrospective study was carried out on urine samples of patients with upper/lower urinary obstructive from two specialist urology referral hospitals with a positive culture and sensitivity tests between January 2011 and December 2020. The patients’ case notes were retrieved, and their urine culture, sensitivity results and mode of treatment were analyzed. These data were collated using Microsoft Excel, and they were analysed using SPSS version 20.

Results: 314 urine samples had positive culture and sensitivity tests. All were Gram-negatives: Klebsiella, Escherichia coli, Pseudomonas, Proteus and Citrobacter spp. in decreasing frequency. Among the quinolones, levofloxacin {56.7% (178)} had the highest moderate-high (M-H) sensitivity to the Gram-negative uropathogens; followed by Ciprofloxacin {46.2 % (145)} and Ofloxacin {19.1% (60)}.

The gram-negatives were most sensitive to streptomycin {75.5% (237)} and gentamicin 62.4% (196)} and also least resistant to them. (Streptomycin 11.1%; gentamicin 21.0%) The highest resistance was to Nalidixic acid {90.1%, (225)}, peflacine {76.1% (239)}, Augmentin {73.6% (231)} and Ampicillin{72%(226)}.

Conclusion: Among the commonly available antibiotics in our study, the gram-negative uropathogens are the most sensitive and least resistant to streptomycin, gentamycin and levofloxacin. Levofloxacin had the best sensitivity and lowest quinolones resistance compared to ciprofloxacin and ofloxacin. There is very low sensitivity and high resistance to nalidixic acid, ampicillin, Augmentin, Septrin and Peflacine.