Characteristics of pathogens causing urinary tract infections in hospitalsin North America: Results from the SENTRY Antimicrobial Surveillance Program, 1997
Rn. Jones et al., Characteristics of pathogens causing urinary tract infections in hospitalsin North America: Results from the SENTRY Antimicrobial Surveillance Program, 1997, DIAG MICR I, 35(1), 1999, pp. 55-63
Urinary tract infection (UTI) is common and involves pathogens with changin
g susceptibility patterns. The SENTRY Antimicrobial Surveillance Program ev
aluates international pathogen incidence patterns to defect and manage the
emergence of resistant strains. We describe the antimicrobial resistance pa
tterns among 1617 pathogens recovered from UTIs during the third-quarter of
1997 in North America (United States and Canada), as part of this worldwid
e program. The isolates were tested against move than 50 antimicrobial agen
ts (20 reported) by reference broth microdilution methods, and selected iso
lates were characterized by pulsed-field gel electrophoresis (PFGE) and aut
omated ribotyping. The Jive most frequently isolated species were Escherich
ia coli (48.6%), Enterococcus spp. (13.7%), Klebsiella spp. (12.0%), Pseudo
monas aeruginosa (6.2%), and Enterobacter spp, or Proteus mirabilis (3.8% e
ach). For each nation, imipenem and cefepime produced the widest spectrum o
f coverage among the beta-lactams and amikacin was best among the aminoglyc
osides. For Gram-negative species, high resistance among beta-lactam antimi
crobial agents was noted especially for various penicillins against E. coli
(37.9% to 42.8%) and for the cephalosporins tested against enterococci (99
.4% and 100%). Approximately 7.0% of enterococci in the LISA were vancomyci
n-resistant (88% with Van A). P. aeruginosa provided the most consistent le
vels of resistance, but the following agents were most active against these
organisms: amikacin (96.6 to 97.4% susceptible), tobramycin (89.5 to 100.0
%), piperacillin/tazobactam (89.5 to 100.0%), piperacillin (89.5 to 96.6%),
imipenem (89.7 to 92.1%), cefepime (77.6 to 89.7%), and ceftazidime (82.9
to 86.2%). E. coli (2.2 to 2.7%), K. pneumoniae (6.2 to 6.4%), and a single
Enterobacter cloacae strain produced extended-spectrum p-lactamases; and f
ive other Enterobacter spp. were likely to have expressed chromosomally med
iated (Amp C) stably derepressed cephalosporinases with associated resistan
ce to ceftazidime (16.7 to 21.2% resistance). These data demonstrated that
several UTI isolates in SENTRY hospitals have high levels of resistance to
various classes of antimicrobial agents with little evidence of clonal diss
emination. (C) 1999 Elsevier Science Inc.