Stewardship / Resistance Scan for Jan 22, 2019

Antibiotics for respiratory infections
UTI treatment in older adults
Super donors for fecal transplant
Resistant cholera in Ghana

Study finds high rate of antibiotic prescribing for respiratory infections

A new study by Emory University researchers reports that more than half of the patients visiting primary care clinics in the university's healthcare network with acute respiratory infections (ARIs) received antibiotics, with substantial variation in prescribing rates by site and provider. The findings were published in Open Forum Infectious Diseases.

The cross-sectional study, conducted from October 2015 through September 2017, examined all patients with a presenting diagnosis of ARI (as indicated by the ICD-10 code) at Emory Clinic's 15 primary care clinics. The researchers also looked at patient demographic data (age, race, and gender), comorbid conditions, the presence of co-infection, and provider type. Provider-specific prescribing rates were compared within and between clinic sites, and multivariable logistic regression was used to determine the impact of patient, provider, and clinic characteristics on antibiotic prescribing.

Of the 9,600 eligible visits with a primary diagnosis of ARI, 53.4% resulted in antibiotics being prescribed. When data were summarized at the clinic level, two clinics prescribed antibiotics more frequently than other clinics, with unadjusted prescribing rates of 75% and 72%, respectively.

In multivariable analysis, the odds of an encounter resulting in an antibiotic prescription were independently associated with white race (adjusted odds ratio [aOR], 1.59; 95% confidence interval [CI], 1.47 to 1.73), older age (aOR, 1.32; 95% CI, 1.20 to 1.46 for patients 51 to 64 years and aOR, 1.32; 95% CI, 1.20 to 1.46 for patients over 65 years), and presence of comorbid conditions (aOR; 1.19; 95% CI, 1.09 to 1.30). Of the 109 providers, 13 (12%) had a higher rate of prescribing than predicted by modeling.

"These data lay the foundation for quality improvement interventions to reduce antibiotic prescribing rates," the authors of the study concluded. "Our team is using these data to define the context of peer-to-peer interactions within the outlier clinics as a first step to change prescriber practice."
Jan 18 Open Forum Infect Dis abstract


Alternative antibiotics for UTIs tied to more severe outcomes in elderly

In another study in Open Forum Infectious Diseases, UK researchers report that prescribing alternatives to the recommended empiric antibiotic for urinary tract infection (UTI) in older adults was associated with lower rates of treatment failure but also with higher risk of hospitalization and death.

The retrospective cohort study aimed to compare the risk of adverse outcomes in adults 65 and older prescribed empirical nitrofurantoin versus cefalexin, ciprofloxacin, or co-amoxiclav for suspected UTI. While clinical guidelines in the United States and United Kingdom recommend nitrofurantoin for uncomplicated UTI, previous studies have found that roughly 15% of older adults treated receive cefalexin, ciprofloxacin, or co-amoxiclav for UTIs.

The hypothesis is that clinicians choose these broad-spectrum antibiotics, which are associated with increased rates of adverse events, to prevent treatment failure, worsening of symptoms, and hospitalization. Using an electronic database of primary care records, the researchers looked specifically at risk of treatment failure, hospitalization for UTI, sepsis, or acute kidney injury, or death.

The researchers identified 42,298 patients 65 and older who were prescribed nitrofurantoin, cefalexin, ciprofloxacin, or co-amoxiclav for a UTI. Compared with those receiving nitrofurantoin, patients prescribed cefalexin (OR, 0.85; 95% CI, 0.75 to 0.98), ciprofloxacin (OR, 0.48; 95% CI, 0.38 to 0.61), or co-amoxiclav (OR, 0.77; 95% CI 0.64 to 0.93) had lower risks of treatment failure. But patients prescribed cefalexin or ciprofloxacin had higher odds of hospitalization for sepsis (OR, 1.89; 95% CI, 1.03 to 3.47 for cefalexin; OR 3.21; 95% CI, 1.59 to 6.50 for ciprofloxacin), while patients prescribed cefalexin had higher odds of death (OR, 1.44; 95% CI, 1.12 to 1.85).

The authors of the study say the findings support further reductions in prescribing cefalexin, ciprofloxacin, and co-amoxiclav for UTIs, given their impact on antimicrobial resistance. 
Jan 18 Open Forum Infect Dis abstract


'Super donors' may hold key to success of fecal transplants

A paper yesterday in Frontiers in Cellular and Infection Microbiology suggests that the efficacy of fecal microbiota transplantation (FMT) for inflammatory bowel disease (IBD) and other conditions may depend on "super donors" whose stool can provide the necessary bacteria to help restore the gut microbiome.

While a recent systematic review and meta-analysis of FMT for the treatment of recurrent Clostridoides difficile infection (CDI) reported a cure rate of 92%, the efficacy of FMT for chronic diseases caused by intestinal dysbiosis, such as IBD, has been modest, with much higher variability in patient response. But in a review of FMT trials for IBD, researchers from the University of Auckland and the Broad Institute of MIT and Harvard found that success in IBD patients appeared to be donor-dependent and linked to donors with higher microbial diversity.

"The pattern of success in these trials demonstrates the existence of 'super-donors,' whose stool is particularly likely to influence the host gut and to lead to clinical improvement," senior study author Justin O'Sullivan of the University of Auckland said in a press release.

Further analysis of studies on the microbial profile of donors and recipients before and after FMT revealed specific microbial signatures linked to efficacy, including the presence of "keystone" bacterial species capable of restoring metabolic deficits in recipients. The investigators also found that how those keystone species interact with bacteria in the recipient's gut can influence FMT engraftment—the integration of donor-derived strains into the recipient's gut microbial community—and that underlying genetic differences between donor and recipient, diet, and subsequent antibiotic exposure can influence long-term efficacy.

Sullivan and his colleagues say further characterization of super donors could help standardize FMT therapy and reduce variability in patient response.
Jan 21 Front Cell Infect Microbiol review article
Jan 22 University of Auckland news release


Analysis shows high resistance rates in cholera bacteria in Ghana

Scientists in Ghana analyzed clinical and environmental isolates of Vibrio cholerae, the bacterium that causes cholera, from in and around the capital city of Accra and discovered that 97% are multidrug-resistant (MDR).

Writing yesterday in BMC Infectious Diseases, the investigators explain that they sampled water from 11 locations in four communities in Greater Accra from October 2015 to January 2016. They collected 244 samples from streams, shallow wells, storage containers, and spigots, and 33 of them (13.5%) tested positive for V cholerae.

Of those, they assessed 11 that were positive for the 01 serotype, as well as 40 clinical samples that were also positive for the 01 serotype, which is the strain most commonly circulating in the country. No tap water tested positive for the 01 strain, but 5.6% of samples (5 of 90) were positive for V cholerae.

All isolates were resistant to one or more of the eight antibiotics tested, and one—a clinical isolate—was resistant to all eight. Over 97% of the isolates were MDR, and 82% harbored the tcpA El tor resistance gene. Only four of the clinical isolates were resistant to ciprofloxacin and six to doxycycline; the remainder were susceptible.

The authors conclude, "This study showed an increasing trend in multidrug resistant Vibrio cholerae O1 with pathogenic potential in domestic water sources."
Jan 21 BMC Infect Dis study

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