Antimicrobial resistance patterns of urine culture specimens from 27 nursing homes: Impact of a two-year antimicrobial stewardship intervention

Abstract

AbstractObjective:Identify changes in the prevalence and antimicrobial resistance patterns of potentially pathogenic bacteria in urine cultures during a 2-year antimicrobial stewardship intervention program in nursing homes (NHs).Design:Before-and-after intervention study.Setting:The study included 27 NHs in North Carolina.Methods:We audited all urine cultures ordered before and during an antimicrobial stewardship intervention. Analyses compared culture rates, culture positive rates, and pathogen antimicrobial resistance patterns.Results:Of 6,718 total urine cultures collected, 68% were positive for potentially pathogenic bacteria. During the intervention, significant reductions in the urine culture and positive culture rates were observed (P= .014). Most of the identified potentially uropathogenic isolates wereEscherichia coli(38%),Proteusspp (13%), andKlebsiella pneumoniae(12%). A significant decrease was observed during the intervention period in nitrofurantoin resistance amongE. coli(P≤ .001) and ciprofloxacin resistance amongProteusspp (P≤ .001); however carbapenem resistance increased forProteusspp (P≤ .001). Multidrug resistance also increased forProteusspp compared to the baseline. The high baseline resistance ofE. colito the commonly prescribed antimicrobials ciprofloxacin and trimethoprim-sulfamethoxazole (TMP/SMX) did not change during the intervention.Conclusions:The antimicrobial stewardship intervention program significantly reduced urine culture and culture-positive rates. Overall, very high proportions of antimicrobial resistance were observed among common pathogens; however, antimicrobial resistance trended downward but reductions were too small and scattered to conclude that the intervention significantly changed antimicrobial resistance. Longer intervention periods may be needed to effect change in resistance patterns.