Methicillin-resistant Staphylococcus aureus as a uropathogen in an Irish setting

Urinary tract infections are one of the most common infectious diseases diagnosed in the community and in the hospital setting. Their treatment is complicated by drug-resistant pathogens and the colonization by microbes of indwelling urinary catheters. This study assessed the occurrence and antimicrobial susceptibility of methicillin-resistant Staphylococcus aureus (MRSA) uropathogens isolated for 5 consecutive years at University Hospital Waterford between 2010 and 2014. We created 4 clinically relevant subdivisions, based on urine source: hospital inpatients, patients from the Emergency Department, patients referred from their General Practitioner, and Nursing Home patients. We performed a retrospective review from the hospital's electronic microbiological system and calculated resistance rates for each of the standard antimicrobial agents. During the 5-year study period, we studied 151 urine isolates obtained from 128 patients who had an MRSA cultured in their urine sample. There was 100% resistance of all MRSA isolates to Flucloxacillin and Coamoxiclav. Ninety-eight percent of isolates were resistant to Ciprofloxacin. The resistance rate for Trimethoprim was 7.4% and there was only 2.7% resistance for Nitrofurantoin. For a clinical subset of patients, we also demonstrated 100% sensitivity for samples tested against Teicoplanin and Vancomycin. Urinary MRSA is an infrequently studied phenomenon, but with the rising trend of hospital superbugs nationally, its management is of critical importance. Suitable agents to address this within our population include Nitrofurantoin in the well patient requiring urinary MRSA eradication or Vancomycin/Teicoplanin in the unwell patient requiring intravenous therapy. In all groups, fluoroquinolones should be avoided due to significant resistance rates.