Stewardship / Resistance Scan for May 02, 2019

News brief

Study links quinolone ear drops to increased risk of eardrum perforation

The results of a comparative safety study show that the use of quinolone ear drops to treat acute otitis externa (AOE) in children and adults is associated with a previously unreported increased risk of tympanic membrane perforation (TMP), researchers from the University of Florida report today in Clinical Infectious Diseases.

Using Medicaid clinical encounter and pharmacy billing records from 1999 through 2010, the researchers analyzed treatment outcomes in 94,333 patients treated for AOE, an uncomplicated ear infection that is not known to cause eardrum perforation. Quinolone ear drops and other ototopical antibiotics are frequently used to treat AOE, but because quinolones have been linked to soft-tissue damage, such as tendon rupture, the researchers wanted to see whether quinolone ear drops increase the risk of TMP.

Of the patients included in the study, 43,653 were treated with quinolone ear drops with or without corticosteroids and 50,680 were treated with neomycin-plus-hydrocortisone ear drops. Overall, 38 cases of TMP were diagnosed in patients exposed to quinolone ear drops during follow-up, compared with 25 in neomycin-exposed patients. When adjusted for demographics and other covariates, the risk of TMP associated with quinolone ear drops was more than twice that of neomycin ear drops (adjusted hazard ratio [HR], 2.26; 95% confidence interval [CI], 1.34 to 3.83).

When comparing individual quinolone preparations against neomycin, the adjusted HRs were 2.53 for ofloxacin (95% CI, 1.27 to 5.05), 2.24 for ciprofloxacin plus hydrocortisone (95% CI, 1.03 to 4.85), and 2.30 for ciprofloxacin plus dexamethasone (95% CI, 1.09 to 4.87). Sensitivity analyses were consistent with the primary analysis.

The authors of the study conclude that, given the findings, the risks and benefits of otic quinolones should be considered prior to treatment of AOE. "Therapy duration, volume dispensed, and refills should be limited to what is necessary to ensure clinical cure," they write. "Patients should be counseled on risk of TMP and monitored for TMPs in follow-up visits."
May 2 Clin Infect Dis abstract

Officials detail MDR Shigella outbreak in Vermont retirement community

A report today from the Centers for Disease Control and Prevention (CDC) and the Vermont Department of Health (VDH) describes a foodborne outbreak of diarrhea caused by multidrug-resistant (MDR) Shigella sonnei in a Vermont retirement community.

Writing in the latest Morbidity and Mortality Weekly Report (MMWR), CDC and VDH epidemiologists say the outbreak occurred in from Oct 1, 2018, through Nov 8, 2018, and sickened 75 residents, visitors, and staff members (24 with confirmed infections and 51 with probable infections). The median patient age was 80, and 75% of patients were female. Six of the patients were hospitalized and two died, although shigellosis was not considered to be the primary cause of death.

High-quality single nucleotide polymorphism analysis predicted that initial isolates from the outbreak were MDR and closely related to a concurrent multistate cluster. Antibiotic susceptibility testing found resistance to trimethoprim-sulfamethoxazole, ampicillin, and ceftriaxone and decreased susceptibility to azithromycin.

Interviews and a review of facility records indicate the earliest cases involved a staff member who prepared food while ill from Oct 11 through Oct 14 and six visitors who dined at the facility on Oct 14. A questionnaire was subsequently given to residents and staff members asking about meal exposure and other known shigellosis risk factors.

A case-control study that included 36 patients and 172 residents and staff members who didn't get sick during the outbreak period found that illness was associated with eating several meals at the facility from Oct 11 through 14. The strongest associations were found among those who dined at the facility on Oct 14 (odds ratio [OR], 5.6; 95% CI, 2.4 to 14.10), specifically during brunch (OR, 5.5; 95% CI, 2.3 to 13.3) and breakfast (OR, 5.3; 95% CI, 1.2 to 22.9).

The authors say the outbreak demonstrates that MDR shigellosis, which is rare in retirement communities, can affect a wide range of populations. In addition, they write, the fact that the outbreak likely started with a staff member who was working while ill highlights the need for nonpunitive sick leave policies.
May 3 MMWR Notes from the field

News Scan for May 02, 2019

News brief

New Ebola cases push DRC total past 1,500 as deaths approach 1,000

The Democratic Republic of the Congo (DRC) health ministry said today that Ebola infections have been confirmed in 15 more people, 2 of them health workers.

All of the cases are from the current known hot spots, including 7 in Katwa. The others are from Musienene (3), Butembo (2), Mandima (2), and Mabalako (1). The new health worker infections involve people from Katwa and Musienene, pushing the number of healthcare workers sickened in the outbreak to 94, including 33 deaths.

The new illnesses push the overall number of cases to 1,510, which includes 1,444 confirmed and 66 probable infections. Health officials are still investigating 286 suspected cases.

Ten more people died from their Ebola infections, 7 of them in the community or in hospitals. Three occurred in Ebola treatment centers, two in Butembo and one in Katwa. Total outbreak deaths have now reached 994.
May 2 DRC statement

Reports from Nepal detail country's first H5N1 avian flu case

Media outlets from Nepal today, citing the country's health ministry, reported the country's first human H5N1 avian flu case, involving a 21-year-old man who apparently died from his infection.

The country has seen sporadic H5N1 outbreaks in poultry since March, most recently at a commercial duck farm in Bagmati zone, which surrounds Kathmandu. The Himalayan Times said the patient is from Kavrepalanchok district in the south central part of the country. He died on Mar 29, and tests the next day revealed H5N1. The samples have been sent to Japan for further testing, according to the report.

Nepal's case would mark the world's first confirmed H5N1 case since 2017. Since 2003, the World Health Organization (WHO) has reported 860 human H5N1 cases, 454 of them fatal. Egypt, Indonesia, and Vietnam are among the hardest-hit countries.
May 2 Himalayan Times story
WHO background on H5N1 cases

FDA approves Dengvaxia, Sanofi's controversial dengue vaccine

Yesterday the US Food and Drug Administration (FDA) approved Dengvaxia, the world's first dengue vaccine, for use in children ages 9 through 16 who have had at least one laboratory-confirmed previous dengue infection and live in endemic areas.

"As the second infection with dengue is often much more severe than the first, the FDA's approval of this vaccine will help protect people previously infected with dengue virus from subsequent development of dengue disease," said Peter Marks, MD, director of the FDA's Center for Biologics Evaluation and Research, in a press release.

The list of caveats comes after Sanofi Pasteur's vaccine caused public outcry in the Philippines in 2017, when it was discovered the vaccine had been administered to dengue-naive schoolchildren. In some cases, the vaccine can act as a "priming" infection in dengue-naive recipients, making subsequent infections severe and life-threatening.

The World Health Organization has since recommended the vaccine be administered only to those with evidence of prior dengue infection.

Dengvaxia is a live-attenuated vaccine and contains genes of each of the four subtypes of dengue. Dengue is endemic in the US territories of American Samoa, Guam, Puerto Rico, and the US Virgin Islands.
May 1 FDA press release

Merck steps up MMR production in wake of US measles outbreaks

Merck, the sole provider of a measles vaccine in the United States, said it is stepping up production of the measles, mumps, and rubella (MMR) vaccine to meet the demands, but supplies have not yet been outpaced by the growing number of US cases.

According to a Reuters story, Merck said earlier this week that US sales of MMR and chickenpox vaccines rose around 10%, to $343 million in the first quarter.

As of Apr 26, the United States has recorded 704 measles cases, the most in any year since 1994, and the highest number recorded since the virus was eliminated in 2000.

The resurgence has been linked to vaccine hesitancy, close-knit communities, and international measles outbreaks, according to the latest measles report published this week in Morbidity and Mortality Weekly Reports (MMWR).

"Among the 704 cases, 503 (71%) were in unvaccinated persons and 689 (98%) occurred in U.S. residents. Overall, 66 (9%) patients were hospitalized," the report said.
May 1 Reuters story
Apr 29 MMWR report

WHO: Republic of Congo sees more than 6,000 chikungunya cases

The Republic of the Congo in February declared a chikungunya outbreak, and cases have not topped 6,000, according to a WHO statement yesterday.

Since Jan 1, officials have reported 6,149 suspected cases of chikungunya in the country, with approximately 54% of reported cases being reported in women. The WHO warned, however, that the number of cases is likely underestimated.

"The scale of this outbreak has likely been underestimated given the limited detection capacity of the surveillance system in the country. Several mosquito breeding sites in affected areas and inadequate vector control mechanisms also represent major contributing factors for the outbreak," the WHO said.

So far, no deaths have been reported in any of the eight health departments reporting cases. This is the second chikungunya outbreak in the Congo since 2011, the WHO said, but no seasonal patterns have been detected.
May 1 WHO statement