Antibiotic Resistance Pattern of Urinary Tract Isolates

Original article


Shaban R. Bagar¹, Awad A. Hussein², Abdullah M. Elahwel³, Sabah M. H. Alani¹

¹-Department of Medical Microbiology; ²-Department of Surgery; ³-Department of Medicine Faculty of Medicine, Al-Tahady University, Sirt, Libya

JMJ Vol. 7, No. 2 (Summer 2007):116-121


Objectives: To document the incidence of resistance against commonly used antimicrobials in uropathogens isolated from outpatients in Sirt, Libya. Methods: Six thousand nine hundred and thirty-one consecutive urine samples were collected from patients with symptoms suggestive of urinary tract infections at the New Central Polyclinic in Sirt, Libya from 2002 to 2005. Samples were cultured on MacConkey Agar with crystal violet and pure isolates with colony counts of 10 or above were identified and tested for antimicrobial resistance by the Kirby-Bauer method. Results: One thousand six hundred and ninety-nine cultures were positive. Escherichia coli was isolated from 1265 female and 301 male patients, Klebsiella spp. was isolated from 81 female and 18 male patients, Pseudomonas aeruginosa was isolated from 16 female and 9 male patients and Proteus spp. was isolated from 7 female and 2 male patients. In E. coli, the highest resistance rates (20 to 70%) were seen against Ampicillin, Co-trimoxazole, Doxycycline, Chloramphenicol, and Nalidixic acid, with little difference across age and gender groups. Resistance rates against 1st generation cephalosporins, Gentamicin and Nitrofurantoin were 7 – 8% among infants but increased to around 20% with age and there was little difference between the gender. Resistance against Amoxycillin-clavulanate and Amikacin was absent among infants but rose with age to reach levels of 13% and 14 % respectively in men above the age of 50 years. Resistance to Ciprofloxacin was absent among infants and increased with age up to 5%. Only 25% of E. coli isolates were simultaneously sensitive to the older antimicrobials (Ampicillin, Co-trimoxazole, Doxycycline, Chloramphenicol, Nalidixic acid, 1st generation cephalosporins, Gentamicin and Nitrofurantoin) but no isolate was simultaneously resistant to all of them. Conclusion: Given the high rates of resistance to commonly used antimicrobials such as Ampicillin, Co-trimoxazole, Doxycycline, Chloramphenicol, Nalidixic acid, and even 1st generation cephalosporins and Gentamicin, one cannot recommend their use for severely ill patients without a sensitivity test report. Among the orally active antimicrobials, Nitrofurantoin remains a fair choice for lower urinary tract infections in an outpatient setting without sensitivity testing. Ciprofloxacin showed even lower resistance rates but its use should be restricted to preserve the general utility of all fluoroquinolones. Amoxycillin-clavulanate and Amikacin remain good choices for life-threatening infections except those in elderly male patients, who are more likely to have complicated disease and harbour resistant strains. The fact that no E. coli strain was simultaneously resistant to all the older antimicrobials suggests that culture and sensitivity testing should be used more widely to allow the continued use of these drugs and prevent the selection of resistance to the newer antimicrobials, which should be reserved for emergent situations.

Keywords: Outpatients, Urinary tract infections, Escherichia coli, Antimicrobial resistance, Libya