Nursing homes as a reservoir of extended-spectrum beta-lactamase (ESBL)-producing ciprofloxacin-resistant Escherichia coli.
BACKGROUND
To assess the prevalence and risk factors for faecal carriage of fluoroquinolone-resistant, extended-spectrum beta-lactamase (ESBL)-producing, Escherichia coli (MDR E. coli) among residents in nursing homes in Northern Ireland.


METHODS
Between January 2004 and May 2006, retrospective histories of hospital admissions, antimicrobial treatment and co-morbidities were collected. Faecal samples were cultured for MDR E. coli. These isolates and their ESBL genes were typed by a reference laboratory.


RESULTS
Of the 294 patients included in the study, faecal samples from 119 (40.5%) grew MDR E. coli. The proportion of carriers in the different homes ranged from 0% to 75%. Epidemic strain A belonging to the ST131, O25:H4 lineage with the CTX-M-15 enzyme accounted for 58 (49%) of all isolates; its proportion varied from 0% to 100% among homes. Fifty-one percent of carriers had no history of recent hospital admission and only 13.5% had a known history of ESBL E. coli colonization or infection. In a multivariate logistic regression model, days of fluoroquinolone use [odds ratio (OR) = 1.33, 95% confidence interval (CI) 1.04-1.69, P = 0.02] and a history of urinary tract infection (OR = 2.56, 95% CI 1.37-4.78, P = 0.003) were the only variables independently associated with the risk of carrying MDR E. coli.


CONCLUSIONS
The high level of faecal carriage of MDR E. coli in nursing home residents demonstrates their importance as a reservoir population. Public health measures to combat spread of these organisms should address the needs of this group.
Rooney
Paul J
PJ
Department of Microbiology, Belfast City Hospital, Belfast BT9 7AD, UK. paul.rooney@belfasttrust.hscni.net
O'Leary
Maureen C
MC
Loughrey
Anne C
AC
McCalmont
Mark
M
Smyth
Brian
B
Donaghy
Philip
P
Badri
Motasim
M
Woodford
Neil
N
Karisik
Edi
E
Livermore
David M
DM
D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002353:Carrier State / Q000453:epidemiology* / Q000382:microbiology; D002939:Ciprofloxacin / Q000494:pharmacology*; D024901:Drug Resistance, Multiple, Bacterial; D004926:Escherichia coli / Q000187:drug effects* / Q000302:isolation & purification; D004927:Escherichia coli Infections / Q000453:epidemiology* / Q000382:microbiology; D005243:Feces / Q000382:microbiology; D005260:Female; D006801:Humans; D008297:Male; D009660:Northern Ireland / Q000453:epidemiology; D009735:Nursing Homes; D015995:Prevalence; D001618:beta-Lactamases / Q000096:biosynthesis*; D047090:beta-Lactams / Q000494:pharmacology*
D000900:Anti-Bacterial Agents; D047090:beta-Lactams; D002939:Ciprofloxacin; D001618:beta-Lactamases