News Scan for Apr 12, 2019

News brief

Deadly flu outbreak strikes remote Laotian tribe

An outbreak of 2009 H1N1 seasonal flu in a remote indigenous hill tribe in Laos killed 16 people and triggered a quick response from local health officials in Thailand, according to a report from the US Centers for Disease Control and Prevention (CDC), which also assisted.

The outbreak in Phongsaly Province occurred in December and January and came to the attention of public health officials because of its high death rate. Authorities quickly sent antiviral drugs and provided health education and hygiene and sanitization interventions to slow the spread of the outbreak.

As part of the response, the CDC regional flu program in Thailand worked with Thailand's health ministry to send an emergency supply of oseltamivir from Thailand to Laos in less 24 hours. Health officials also redirected flu vaccine from Laos' ongoing seasonal flu campaign to the tribe, enabling more than 2,200 people to be vaccinated and achieving a 74% vaccination rate. The CDC said no new deaths have been reported, and the epidemic curve shows a decline.

An investigation is underway into why the 2009 H1N1 outbreak was so deadly. However, the CDC added that rural, remote populations are often not vaccinated against seasonal flu and typically have little access to healthcare. Malnourishment and underlying medical conditions are additional risk factors, it said.

The CDC said close connections between animals and people in rural Laos raise the risk of flu viruses spreading among people and animals, conditions that can give rise to novel flu viruses. It added that a cooperative agreement between the CDC and Laos has improved the country's ability to respond to flu threats and immunize people against seasonal flu. "Due to this relationship, Laos was the first lower-middle income country to establish its own sustainable influenza vaccination program," it said.
Mar 6 CDC international program highlight

 

H5 outbreaks strike poultry in Bhutan and Bulgaria

In the latest highly pathogenic avian flu developments in poultry, Bhutan reported an outbreak involving H5N1 and Bulgaria reported three more outbreaks from H5N8, according to separate reports from the World Organization for Animal Health (OIE).

Bhutan's outbreak, its first since August 2018, struck backyard birds in Chhukha district in the country's southwest. The outbreak's location is close to the Indian border town of Jaigoan in Bengal state. The event began on Apr 6, killing 264 of 2,000 susceptible birds. The remaining ones were culled, as were 2,000 more thought to be at high risk of infection. So far, the source of the virus hasn't been determined.

Elsewhere, Bulgaria's latest H5N8 outbreaks occurred in Plovdiv province in the south central part of the country, with start dates ranging from Apr 4 to Apr 8. One involved backyard birds and two occurred on poultry farms. Taken together, the virus killed 635 of 203,787 birds.
Apr 11 OIE report on H5N1 in Bhutan
Apr 11 OIE report on H5N8 in Bulgaria

ASP Scan (Weekly) for Apr 12, 2019

News brief

Study finds high rates of macrolide-resistant M genitalium in Chinese men

Originally published by CIDRAP News Apr 11

Chinese and US researchers report today in Clinical Infectious Diseases that macrolide use is associated with an almost double rate of antibiotic resistance in urethritis caused by Mycoplasma genitalium in men, and a related commentary questions whether it's time for the US and Canada to reconsider macrolides as first-line empiric treatment for men with symptomatic urethritis.

The investigators tested 1,816 Chinese men who had symptomatic urethritis, 358 of whom (19.7%) were infected with M genitalium. The men who had taken macrolides had a 96.7% higher rate of macrolide resistance than those who had not taken the drugs. The researchers also noted that 88.9% of M genitalium isolates harbored genes with mutations conferring macrolide resistance, and 89.5% had genes responsible for fluoroquinolone resistance.

In a related commentary, Ameeta Singh, BMBS, MSc, of the University of Alberta, and Lisa Manhart, PhD, of the University of Washington, challenge the use of macrolides in non-gonococcal urethritis (NGU) in men. They say the high prevalence of both M genitalium and macrolide resistance "has called into question the routine use of macrolides (single dose azithromycin) for the empiric treatment of NGU" in Canada and the United States.

They note that recent UK, European, and Australian guidelines for managing NGU now recommend against azithromycin for routine first-line treatment.
Apr 11 Clin Infect Dis abstract
Apr 11 Clin Infect Dis commentary

 

Researchers show variations in accuracy of 3 XpertMRSA versions

Originally published by CIDRAP News Apr 11

Swiss researchers evaluated three consecutive versions of the XpertMRSA rapid test (G3, Gen3, and NxG) for detecting methicillin-resistant Staphylococcus aureus (MRSA), finding that the sensitivity improved with each successive commercial version, but not statistically significantly, while specificity and positive likelihood ratios were significantly lower in the Gen3 version.

Writing in Clinical Microbiology and Infection, the scientists say they simultaneously screened MRSA samples by culture and rapid polymerase chain reaction via the three XpertMRSA tests, the earliest version of which was G3. They analyzed 3,512 samples by G3, 2,794 by Gen3, and 3,288 by NxG.

Among the three groups, 5.0%, 4.7%, and 4.3% of samples, respectively, tested positive for MRSA by culture. The sensitivity of the XpertMRSA rapid test improved with each newer version (71.4, 82.3, and 84.3%, respectively), but non-significantly. The specificity (98.4, 96.8, and 99.1, respectively) and the positive likelihood ratios (45.7, 25.6, and 97.1, respectively) were significantly lower in the Gen3 version (P <0.00001).

The authors conclude, "These significant differences in performance shows the importance to evaluate each new version of a commercial test."
Apr 4 Clin Microbiol Infect study

 

Study: 2.7 million penicillin allergies in the UK incorrect

Originally published by CIDRAP News Apr 11

Up to 2.7 million people in the United Kingdom with documented penicillin allergies (PenA) on  their medical charts do not have a true allergy, according to a report yesterday in the Journal of Antimicrobial Chemotherapy.

This was the first study to assess the prevalence of PenA designation in the United Kingdom, the authors said, and it was conducted by examining electronic medical records from the British National Health Service over the course of 1 year (2013-2014). PenA prevalence was 5.9%, and was more common in the elderly and in female patients.

PenA was also associated with an increased risk of re-prescription of a new antibiotic class within 28 days (relative risk [RR], 1.32), MRSA infection/colonization (RR, 1.90) and death during the year subsequent to the study (RR, 1.08). The total number of antibiotic prescriptions was increased in patients with PenA, the authors said.

PenA is one of the most common drug allergies and causes clinicians to use different and in many cases more antibiotics when prescribing to patients with a PenA note in their medical charts. The researchers estimate that 2.7 million people in England have incorrect PenA records.

Conducting a true oral challenge for patients with a PenA designation could help with more precise antibiotic prescribing, the authors concluded, as many patients have been designated a PenA for adverse reactions that do not represent a true allergy.
Apr 10 J Antimicrob Chemother study

 

MCR-1 E coli found in cluster of New York City liver transplant patients

Originally published by CIDRAP News Apr 9

A study yesterday in Antimicrobial Agents and Chemotherapy describes the detection of MCR-1-carrying Escherichia coli in three liver transplant patients at a New York City hospital.

The three patients at Columbia University Irving Medical Center were found to be colonized with MCR-1–carrying E coli in 2015 after undergoing liver transplants. MCR-1, which confers resistance to the last-resort antibiotic colistin, was first discovered in China in 2015 and has since spread to more than 30 countries. To date, 53 US cases have been reported, but this report represents the earliest documented healthcare-related cluster of MCR-1 in the country.

Two of the liver transplant patients (patients 2 and 4) were epidemiologically linked, potentially through same-day endoscopic procedures, to an index patient (patient 1) who had been infected with MCR-1 E coli and successfully treated. Patient 2 underwent endoscopic retrograde cholangiopancreatography (ECRT) on the same day as patient 1 in March 2015, and then underwent ECRT again in September 2015, on the same day that patient 4 underwent gastroduodenoscopy. Patient 3 had no epidemiologic links to the other cases. The three colonized patients did not experience infections in more than 2 years of follow-up.

Multi-locus sequence typing indicated that all the MCR-1 E coli isolates belonged to sequence type (ST)117 and were related, and whole-genome sequencing revealed that, in addition to carrying MCR-1 on identical plasmids, the isolates also harbored resistance genes for beta-lactams, aminoglycosides, sulphonamides, trimethoprim, macrolides, chloramphenicol, and tetracyclines. Retrospective molecular screening of more than 500 samples (cephalosporin-resistant E coli isolates and discarded surveillance rectal swabs) found no other MCR-1–carrying isolates.

"The detection of this cluster demonstrates the potential for silent dissemination of mcr-1 in the hospital setting through asymptomatic colonization and suggests a possible role for same-day endoscopy-related transmission, independent of using the same endoscope," the authors of the study write. "While infective episodes have the greatest impact on patient outcomes, detection of silent colonization may play an important role in stemming the spread of mcr-1.
Apr 8 Antimicrob Agents Chemother abstract

 

Analysis finds declining outpatient antibiotic use in Massachusetts

Originally published by CIDRAP News Apr 9

Researchers from the Massachusetts Department of Public Health and Harvard reported yesterday in Open Forum Infectious Diseases that outpatient antibiotic prescribing in Massachusetts fell by nearly 17% from 2011 to 2015. Their analysis also found a wide variation in antibiotic use by census tract.

Using outpatient prescription claims from the Massachusetts All-Payers Claims Database from 2011 through 2015, the researchers measured claims for antibiotic prescriptions and calculated rates per 1,000 people by calendar year, sex, and age-group. Population-wide antibiotic use was measured for major antibiotic classes and the most frequently prescribed individual antibiotics. To describe in-state geographic patterns, the investigators measured prescribing rates for the four most frequently prescribed antibiotics—penicillins, quinolones, cephalosporins, and macrolides—stratified by the US census tract of residence documented in the claim.

The study population had 17.1 million antibiotic claims prescribed for 4.9 million members over the study period. The overall annual rate of outpatient antibiotic use for individuals 64 years old and younger was 696 prescriptions per 1,000 people, falling from 759 to 652 prescriptions per 1,000 people from 2011 through 2015, a decline of 16.7%. The highest rate of prescribing was among infants, and the lowest was among children and young adults aged 10 to 19 years. In 2015, 68% of people had no antibiotic prescription, and 17% had only one.

The researchers noted dramatic variability in antibiotic use by census tract within the state, with penicillin use ranging from 31 to 265 prescriptions per 1,000 people, macrolide use ranging from 28 to 333, cephalosporin use ranging from 8 to 89, and quinolone use ranging from 13 to 118. In general, urban areas had lower antibiotic use among the four major antibiotic classes.

The authors of the study believe that the detailed characteristics of populations and providers with higher prescribing rates can be used to focus education and monitoring. They say they plan to share these results with providers and the community through online reports.

"Combining these data with clinical indications for antibiotic prescriptions, particularly in areas with higher prescribing rates, will aid in shaping stewardship interventions," they write.
Apr 8 Open Forum Infect Dis abstract

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