Stewardship / Resistance Scan for Jan 22, 2019

News brief

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

Washington state measles outbreak sickens 22; exposures in Portland area

Washington state's Clark County, which is part of the Portland, Ore., metropolitan area, has declared a public health emergency related to a measles outbreak, with 22 cases confirmed so far, along with 3 more suspected cases.

The outbreak began in the Vancouver, Wash., area in early January, with exposure risks at various locales in the Portland metro area, including a Portland Trailblazers basketball game on Jan 11.

Most of the illnesses have been in children ages 1 to 10, and one patient has been hospitalized, county officials said. Nineteen people were unvaccinated, and immunization status was unverified in the three other cases.

The county is requiring that students and staff without documented immunity be excluded from schools identified as possible exposure sites, and it has set up a call center for questions about the investigation and possible exposure. In a Jan 18 statement announcing the public health emergency, Clark County said the step is needed to ensure that it has enough resources to continue its response and access to resources outside of its region.
Jan 21 Clark County Public Health measles update
Multnomah County measles outbreak information
Jan 18 Clark County public health emergency announcement

In its latest measles update, the US Centers for Disease Control and Prevention (CDC) said 349 cases of measles were confirmed in 2018, the second most since the US eliminated measles in 2000. The cases include illnesses related to outbreaks in New York state, New York City, and New Jersey, mainly involving unvaccinated people in Orthodox Jewish communities. The CDC said 81 imported measles cases were reported in 2018, the most since the disease was eliminated.
Jan 10 CDC measles update

 

CDC: More than 200 cases of acute flaccid myelitis documented in 2018

In its latest update on acute flaccid myelitis (AFM), the CDC yesterday confirmed 5 new cases in the last week, raising 2018's total to 201, the most in any year since the agency began tracking the puzzling condition in 2014.

A total of 40 states have confirmed cases of the polio-like illness, with Texas reporting the most, with 25. Colorado has 16 cases, Ohio has 13, and Washington state has 11. California, Minnesota, and New Jersey each have recorded 10.

AFM affects the spinal cord, leaving patients — almost always children — with partial or total limb paralysis or muscle weakness. The cause of the disease is unknown, but 90% of patients report upper respiratory virus symptoms in the weeks prior to limb weakness.

In a study published today in mBio, researchers provided evidence of enterovirus D68 (EV-D68) in a cluster of AFM cases investigated in Arizona in September of 2016. Enteroviruses have previously been connected to AFM outbreaks. In this study, 3 of 4 confirmed AFM cases had evidence of EV-D68 in either nasal swabs or cerebrospinal fluid material.

As of yesterday's update, the CDC said it will now post AFM case counts biweekly.
Jan 21 CDC update
Jan 22 mBio
study

 

Two new cases of MERS recorded in Saudi Arabia

The Saudi Arabian Ministry of Health (MOH) recorded two new cases of MERS  in recent days, one each in epidemiologic weeks 3 and 4.

In week 3, the MOH said a 40-year-old man from Riyadh was hospitalized for his MERS-CoV (Middle East respiratory syndrome coronavirus) infection. In the week 4 update, the MOH said a 66-year-old man from Riyadh was also hospitalized with MERS.

Neither man had camel contact, and both sources of infection are listed as "primary, community acquired."

The new cases likely lifts on the global total since 2012 to 2,288 cases, at least 806 of them fatal.
Jan 19 MOH update
Jan 22 MOH update

 

New study shows HPV vaccine highly effective, offers herd immunity

A study today in Pediatrics shows that both the quadrivalent (four-strain) and nine-valent human papillomavirus (HPV) vaccines are highly effective and provide herd immunity for women in the United States.

The study was based on four cohorts of vaccine recipients (aged 13 to 26 years) tracked from 2006 to 2017 at two US clinic sites, with the early cohorts receiving the quadrivalent vaccine and the later cohort receiving the nine-valent vaccine. A total of 1,580 women at high risk for HPV infection were included in the study.

Vaccine effectiveness in each wave of recipients was high, from 80.1% to 90.6%. Overall, women vaccinated with the quadrivalent vaccine saw an 80.9% decline in HPV infections.

The study authors also provided evidence of herd immunity. The prevalence of HPV-6, HPV-11, HPV-16, and HPV-18, the four strains of HPV included in the quadrivalent vaccine, dropped among unvaccinated women from 32.4% to 19.4% during the study period.

"This degree of effectiveness is remarkable given the fact that vaccination was defined as having received ≥1 dose (ie, was not defined as having completed the vaccination series) and that women in this study were likely at a substantially higher risk for preexisting HPV infection than those in the HPV vaccine clinical trials because of their reported sexual behaviors," the study authors wrote.

The researchers also reported good protection against strains not included in the vaccine.

In an unexpected finding, herd immunity was not seen among unvaccinated women for the five additional strains of HPV included in the nine-valent vaccine but not in the quadrivalent version. The authors said continued community-level research is needed to monitor this trend.
Jan 22 Pediatrics
study

 

Nigeria, Iran, Denmark report more H5 avian flu detections

In new highly pathogenic avian flu developments, Nigeria reported an H5N1 outbreak in poultry, Iran confirmed another H5N8 event, and Denmark noted a pair of H5N6 detections in wild birds, according to the latest notifications from the World Organization for Animal Health (OIE).

Nigeria's H5N1 outbreak, where the virus is considered endemic, began on Jan 19 and affected backyard birds in Bauchi state in the north central part of the country. The virus killed 27 of 848 susceptible birds, and the remainder are slated for culling. Though the source of the virus hasn't been determined, the OIE report said new pullets had recently been introduced to the farm.

In Iran, the country's agriculture ministry reported another H5N8 outbreak, this time affecting backyard poultry in Qom province. The event began on Jan 2, killing 8,000 of 12,138 birds at the location. Authorities destroyed the surviving birds, and the event is now listed as resolved. Iran reported its last H5N8 outbreaks earlier this month, which struck farms in Mazandaran province.

In Denmark, officials recently reported two H5N6 detections in wild birds, one involving a white-tailed eagle found dead on Dec 22 near Naestved on Zealand island in the east and the other in a buzzard found dead on Jan 4 on a different part of the island. The H5N6 strains detected in European wild birds are not closely related to zoonotic strains in Asia.
Jan 22 OIE report on H5N1 in Nigeria
Jan 19 OIE report on H5N8 in Iran
Jan 15 OIE report on H5N6 in Denmark
Jan 21 OIE report on H5N6 in Denmark

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