A UK multicentre study of the antimicrobial susceptibility of bacterial pathogens causing urinary tract infection.
OBJECTIVE
To determine the prevalence of resistance amongst urinary tract pathogens against antimicrobials used to treat urinary tract infections (UTIs) in the UK to provide data to help direct empirical therapy.


METHODS
During 1999-2000, a total of 1291 bacterial isolates causing UTI were collected from 8 centres in the UK. Isolates were cultured from patients with (1). community-acquired UTI in those less than 65 years old (397), (2). hospital-acquired UTI other than those admitted with pyelonephritis (394), (3). pyelonephritis (108) and (4). community-acquired UTI in those greater than 65 years old (392). After re-identification, MICs for a range of antimicrobials were determined and interpreted using NCCLS procedures and interpretive guidelines.


RESULTS
Escherichia coli was the predominant pathogen in all categories but the total percentage for each category varied (56.3-77.3%). The next three pathogens of importance were Enterococcus faecalis, Klebsiella pneumoniae and Proteus mirabilis which varied in prevalence slightly from category to category. The activity of amoxycillin against E. coli (51.3% susceptible) was greatly reduced as a result of beta-lactamase production and only partially restored by the addition of clavulanic acid (78.8% susceptible). Cefuroxime was very active against E. coli using parenteral form breakpoints (97.1% susceptible) but less so using oral form breakpoints (68.6% susceptible). Cefuroxime was inactive against Enterococcus spp. and Pseudomonas spp. Nitrofurantoin was very active against isolates of E. coli (96.3% susceptible) and E. faecalis but not against K. pneumoniae, P. mirabilis or Pseudomonas aeruginosa. Overall susceptibility to trimethoprim ranged from 58.1% to 84.5% for the most prevalent pathogens. Ciprofloxacin was highly active against the UTI pathogens examined in this study with susceptibilities of between 88.6% and 97.7% for the most prevalent pathogens (E. coli, n=864, 97.7% susceptible) and was the only oral agent tested with activity against Pseudomonas spp.


CONCLUSIONS
These data provide much needed information on the prevalence of antimicrobial resistance amongst pathogens currently causing UTI in the UK.
Farrell
D J
DJ
GR Micro Limited, London, UK. d.farrell@grmicro.co.uk
Morrissey
I
I
De Rubeis
D
D
Robbins
M
M
Felmingham
D
D
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000494:pharmacology* / Q000627:therapeutic use; D000892:Anti-Infective Agents, Urinary / Q000494:pharmacology* / Q000627:therapeutic use; D001424:Bacterial Infections / Q000188:drug therapy / Q000382:microbiology*; D002648:Child; D002675:Child, Preschool; D024881:Drug Resistance, Bacterial; D013293:Enterococcus faecalis / Q000187:drug effects* / Q000302:isolation & purification; D004926:Escherichia coli / Q000187:drug effects / Q000302:isolation & purification; D005260:Female; D006090:Gram-Negative Bacteria / Q000187:drug effects* / Q000302:isolation & purification; D006801:Humans; D007223:Infant; D007711:Klebsiella pneumoniae / Q000187:drug effects / Q000302:isolation & purification; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D011513:Proteus mirabilis / Q000187:drug effects / Q000302:isolation & purification; D006113:United Kingdom; D014552:Urinary Tract Infections / Q000188:drug therapy / Q000382:microbiology*
D000900:Anti-Bacterial Agents; D000892:Anti-Infective Agents, Urinary