Researcher give insight into the importance of antibiograms in outpatient management of urinary tract infections
Nitrofurantoin found to be the best empiric choice for outpatient treatment of acute uncomplicated cystitis in New York State, according to the results of a poster presentation at ID Week 2018, being held in San Francisco, California, this week.
For their research, the investigators from New York focused on prescribing habits for outpatient urinary tract infections and whether or not health care providers have reached the post-antibiotic era for treating them. Treatment for urinary tract infections is becoming more limited in the outpatient setting as resistant infections are on the rise and it was estimated that in 2011, there were 400,000 hospitalizations for urinary tract infections, which cost $2.8 billion. Investigators have found that between 1998 and 2011, there was a 52% increase in the incidence of urinary tract infections, with a larger rate increase for women and older patients. Outpatient prescribing is a driver for antimicrobial use and the lack of guidance on regional susceptibility to help drive prescribing and empiric therapy, does little to help reduce resistance.
After performing a retrospective analysis of positive urine cultures sent to a large laboratory diagnostics center in 2016 from outpatient settings, the investigators reviewed cultures that grew ≥105 CFU/mL across 17 New York State counties and upon identification of bacteria, antimicrobial susceptibilities were performed. From 78,000 isolates, they found a wide variety of microbial growth. “The most prevalent isolates were Escherichia coli, (65.2%), Enterococcus spp (11.9%) and Klebsiella pneumoniae (9.9%). E coli was highly susceptible to nitrofurantoin (NTF, 97.2%) and cefazolin (CFZ, 89.9%) and less susceptible to trimethoprim-sulfamethoxazole (TMP-SMX, 72.9%) and ciprofloxacin (CIP, 78.0%). Enterococcus spp was highly susceptible to NTF (99.0%) and ampicillin (99.8%). K pneumoniae was highly susceptible to TMP-SMX (90.0%) and CIP (95.2%) and markedly less susceptible to NTF (42.0%).”
In female patients, E coli was the most prevalent bacteria while Enterococcus was more common in males. K pneumoniae was problematic across both sexes.
Antibiotic resistance was found to be more prevalent in males and adults 65 and older. Following the creation of the antibiogram for outpatient urinary pathogens in New York, the investigators noted that NTF (nitrofurantoin) is the best empiric choice for outpatient urinary tract infection treatment; TMP-SMX (trimethoprim-sulfamethoxazole) and ciprofloxacin should be avoided as empiric treatment.
Establishing antibiograms to reveal microbial susceptibility for regions, hospitals, etc, can be immensely helpful in guiding prescribing habits and reducing antimicrobial resistance. For infection prevention efforts, the annual production of antibiograms by hospital microbiology is a critical component to education on the importance of not only reducing antimicrobial usage, but also informing smarter practices based upon the unique needs of the area. Further efforts to reduce resistance should underscore the importance of antibiograms and make their presence a requirement and a vital component to provider education and practice.