| epidemiology of antimicrobial resistance among gram-negative organisms recovered from patients in a multistate network of long-term care facilities. | we identified 1,805 gram-negative organisms in cultures of urine samples obtained over a 10-month period from residents of 63 long-term care facilities. the prevalence of fluoroquinolone resistance in escherichia coli was 51% (446 of 874 isolates), whereas the prevalences of ceftazidime and imipenem resistance in klebsiella species were 26% and 6% (84 and 19 of 323 isolates), respectively. the prevalence of resistance varied significantly by facility type, size, and geographic location. | 2009 | 19566445 |