Medicine in Microecology (Dec 2024)
Bacterial etiology and antimicrobial resistance pattern of community-acquired urinary tract infection in older adults
Abstract
Background: Urinary tract infections (UTIs) are a significant cause of morbidity in elderly individuals and remain a persistent challenge for medical professionals. This study aimed to identify the bacteria causing community-acquired (CA) UTIs in older patients, determine their antimicrobial resistance patterns, assess the prevalence of polymicrobial infections, and identify the risk factors. Methods: Urine samples were obtained from patients with symptomatic UTIs and then cultured on blood and MacConkey agar. Positive cultures were identified and tested for antimicrobial susceptibility using the VITEK 2 system. Results: Polymicrobial infections were found in 69/427 (16.16 %) of older patients with CA-UTIs and associated with diabetes (p = 0.007), previous antimicrobial use (p = 0.025), and recurrent urinary infections (p = 0.043). Escherichia coli was the leading pathogen (57.26 %), and Klebsiella pneumoniae was identified in 15.32 % of CA-UTIs. Escherichia coli was more common in non-diabetic patients (60.81 %) than diabetes (43.69 %). However, the rates of Klebsiella species were higher in diabetes (20.39 %) than non-diabetes (14.50 %). Gram-negative uropathogens showed 49.89 % resistance to amoxicillin-clavulanic acid, while imipenem is the least resistant (7.19 %). The gram-positive uropathogens were resistant to 9.80 % of linezolid and highly resistant to erythromycin (74.51 %), tetracycline (72.55 %), and gentamicin (70.59 %). Conclusions: Escherichia coli isolates were the predominant bacteria in the elderly and highly resistant to amoxicillin-clavulanic. The most effective drug against gram-negative bacteria was imipenem, while linezolid proved potently effective against gram-positive bacteria. Diabetes, previous antimicrobial use, and recurrent urinary infections are risk factors for polymicrobial UTIs.
