Resistance Pattern in Mostly Gram-negative Bacteria Causing Urinary Tract Infections

Abstract

Purpose: The antimicrobial prescription in urinary tract infections (UTI) is driven by local data on its pathogenic spectrum and the resistance pattern exhibited by the disease-causing pathogens. We aimed to determine the bacteriological diversity of UTI causing pathogens and antimicrobial resistance in mostly gram-negative bacteria.

Methods: This retrospective hospital-based cross-sectional study analyzed the culture and sensitivity reports of urine samples from a referral centre in the Aljouf region of Saudi Arabia. All the antibiograms from January 1, 2020, to December 31st 2020, were included. The bacterial identification and antimicrobial testing were carried out by the BD Phoenix system (BD Diagnostics, Sparks, MD, USA). Antimicrobial testing was performed as per the Clinical and Laboratory Standard Institute recommendations. Frequencies of multidrug- and extensive drug resistance were calculated.

Results: Of the 1334 non-duplicate urine samples received, 422 (31.6%) bacterial growths were observed. Of these, 383 (90.8%) and 39 (9.2%) were gram-negative and gram-positive bacterial isolations, respectively. E. coli 161 (38.1%), K. pneumoniae 97 (23.0%), and E. faecalis 18 (4.3%) were frequent aetiologies of UTI. 309 (80.7%) of gram-negative bacteria were multidrug-resistant including 88 (23.0%) extensively drug-resistant. Overall, a resistance rate of > 55 % to 1st through 4th generation cephalosporins was observed except for cefoxitin (43.7%). A resistance rate of 37.6% was observed towards carbapenems, with the lowest rate (34.0%) to meropenem.

Conclusion: Multi-drug resistant gram-negative bacteria dominate the pathogenic spectrum of UTI in the region. A high resistance rate to cephalosporins and carbapenems exists in gram-negative organisms, causing UTI.

Keywords: Gram-negative bacteria; Urinary tract infections; antimicrobial resistance; carbapenems; meropenem; multidrug-resistance.