Stewardship / Resistance Scan for Apr 18, 2017

News brief

Azithromycin not found to increase risk of ventricular arrhythmia

A study today in the Canadian Medical Association Journal (CMAJ) has found that use of the antibiotic azithromycin was associated with increased risk of ventricular arrhythmia (abnormal heartbeat) when compared with nonuse of antibiotics, but not when compared with use of amoxicillin.

In the nested case-control study, a team of European researchers used healthcare databases from Italy, the United Kingdom, Germany, the Netherlands, and Denmark to identify patients with ventricular arrhythmia who were new antibiotic users. They were looking to see if there is a link between the use of azithromycin—an antibiotic commonly used to treat respiratory and urinary tract infections—and increased risk of death from ventricular arrhythmia. Concerns about a potential link have been raised by the arrhythmogenic risk associated with another macrolide, erythromycin, but observational studies have to date produced conflicting results.

Of the more than 14 million new antibiotic users identified, 12,874 (0.1%) developed ventricular arrhythmia, and 30 were current azithromycin users. In matching the 30 current azithromycin users with 1,344 case controls, the researchers found that, when compared with nonuse of antibiotics, current azithromycin use was associated with an increased risk of ventricular arrhythmia (adjusted odds ratio [OR] 1.97). But when compared with current use of amoxicillin, the increased risk disappeared (adjusted OR 0.94). The results were consistent across separate databases and 1- and 2-stage pooled analyses.

The authors of the study say the decreased risk with an active comparator "suggests significant confounding by indication," meaning that the risk of ventricular arrhythmia is more likely associated with the patient's infection than with the antibiotic being used.

"This finding suggests that the risk of ventricular arrhythmia is more likely to be due to a person's poor health and caused by their infection, rather than to azithromycin itself," study author Gianluca Trifiro, MD, from the University of Messina, Italy, said in CMAJ news release.

The authors note that because the study used data on community use of antibiotics, the findings should not be extrapolated to the hospital setting, where the health status of patients and the nature of antibiotic use are likely to be different.
Apr 18 CMAJ abstract
Apr 18 CMAJ news release

 

Study identifies compensatory mutations in multidrug-resistant bacteria

A study today in PLoS Biology suggests that multidrug-resistant bacteria acquire compensatory mutations faster than bacteria that are resistant to a single antibiotic, a finding researchers say could open up new paths for novel antimicrobial strategies.

Chromosomal mutations that confer resistance often come with a fitness cost for bacteria in the absence of antibiotics. To counter that fitness cost, bacteria acquire additional mutations, known as compensatory mutations, that enable them to survive and spread. While this evolutionary process has been studied in single-resistant strains, less is known about how multidrug-resistant bacteria acquire compensatory mutations.

In the study, researchers from the Instituto Gulbenkian de Ciencia in Portugal analyzed and compared, in an antibiotic-free medium, the evolution of strains of Escherichia coli with single resistance to rifampicin and streptomycin and strains with resistance to both antibiotics. What they found was that the low-fitness double-resistant E coli strains acquired compensatory mechanisms faster than the single-resistant strains, primarily because of the acquisition of mutations with larger effects.

In addition, the researchers identified mutations that only compensate for double resistance and likely compensate specifically for the interaction between drug resistances.

"Interestingly, this knowledge may provide new grounds for the development of novel antimicrobial strategies that specifically exploit potential weaknesses derived from epistasis between antibiotic resistances in multidrug-resistant bacteria," the authors write.
Apr 18 PLoS Biol study

News Scan for Apr 18, 2017

News brief

Zika birth defects may be underreported in Puerto Rico

Puerto Rico may be underreporting or downplaying the numbers of babies born in the territory with Zika-related birth defects, Stat reported today, citing an unnamed former US health official.

The territory has reported only 16 birth defects, though more than 3,300 women are thought to have been infected. For comparison, in the United States, 65 fetal birth defects have been reported among about 1,300 pregnant women infected with Zika, most of them contracting the virus during travel to affected countries.

Neither Puerto Rico's health department nor its top epidemiologist could comment for Stat's story, which noted that the US Centers for Disease Control and Prevention (CDC) last October stopped reporting on Puerto Rico's pregnancy outcomes. Margaret Honein, MD, chief of the CDC's birth defects branch and member of its Zika response team, said a pregnancy registry agreement bars the CDC from discussing differences in the territories' Zika birth case definitions. Discussions are still under way to align Puerto Rico's case definitions with those of US states, she told Stat.
Apr 18 Stat story

In related developments, seizures and epilepsy have been reported in some babies who have Zika-linked birth defects, and better surveillance for the symptoms and more awareness are needed to help clinicians identify affected patients, CDC experts wrote yesterday in a JAMA Neurology viewpoint.

Cases reports and case series from Brazil have described seizures and epilepsy in babies with probable congenital Zika infections. Infections with other pathogens, such as cytomegalovirus, have also been associated with seizures or epilepsy. Because symptoms can vary, health providers may not always recognize the conditions in infants and young children, which could lead to misdiagnosed or underreported cases of Zika-related epilepsy, the group wrote.

Enhancing surveillance and awareness could help ensure that families get appropriate treatment and support. The experts added that local public health officials in affected areas could partner with epilepsy stakeholders to establish systems, based on local preferences and resources. Another approach would be to add questions about seizures and epilepsy to existing Zika surveillance systems.
Apr 17 JAMA Neurol viewpoint

 

Second case of MERS confirmed in Qatar

Qatar has identified its second MERS case this month, according to a statement translated by Avian Flu Diary (AFD), an infectious disease tracking blog, today. The patient did not travel outside of the country in the past 2 weeks or have direct contact with camels, according to Qatar's Ministry of Public Health.

This is only the 20th case of MERS-CoV (Middle East respiratory syndrome coronavirus) in Qatar since the disease first appeared in humans in 2012. Seven of the 20 patients have died from the virus.

The patient was identified as a 25-year-old male Qatari national who is in stable condition after presenting with symptoms of MERS-CoV. In addition to a lack of travel or contact with camels, the patient had no known contact with other MERS-CoV patients.
Apr 18 AFD post

 

Yellow fever vaccine urged in all of Rio De Janeiro, Sao Paulo states

The US CDC said yesterday that yellow fever vaccination is now recommended for all of Rio de Janeiro and Sao Paulo, two Brazilian states in which the country's biggest cities have so far avoided being included in vaccination campaigns against the current outbreak of the mosquito-borne disease.

The CDC recommends that people traveling  to the states of Minas Gerais, Espirito Santo, Rio de Janeiro, and Sao Paulo (except the city of Sao Paulo), and parts of Bahia state, get vaccinated 10 days prior to travel, and consider getting a booster if their last yellow fever vaccination was more than 10 years ago. All people over the age of 6 months can be vaccinated against yellow fever.

In addition, the Pan American Health Organization (PAHO), in it weekly yellow fever epidemiologic report yesterday, reported 2,422 cases of yellow fever in Brazil, with 326 deaths, as of Apr 12. The case-fatality rate for confirmed cases is 34%.

As was the case last week, there have been no new cases reported in Minas Gerais, the epicenter of the outbreak. But a second wave of cases in Espirito Santo continues. So far, the transmission cycle remains unchanged, but epizootic cases in large cities represent an increased risk of the virus jumping to urban populations of Aedes aegypti mosquitoes.
Apr 17 CDC travel update
Apr 17 PAHO
update

 

CDC issues travel notices for measles in Belgium, Italy, Germany

The CDC yesterday issued travel watches over measles outbreaks in three European countries: Belgium, Italy, and Germany.

In its level 1 advisory, urging travelers to take the usual precautions, the CDC asked travelers to make sure they are protected against measles through vaccination, especially infants ages 6 to 11 months who should receive one dose, and children ages 1 and older who should receive two doses. The agency also urged physicians to keep measles in mind when treating patients who have fever and rash and have recently traveled internationally.

In late March, the World Health Organization said outbreaks in the European region, concentrated in Romania and Italy, were a threat to the area's elimination goals. The European Centre for Disease Prevention and Control (ECDC) said in an Apr 7 update that a number of countries have reported ongoing outbreaks that began in 2016, with 4,025 cases reported in 13 countries as of Mar 31.

The CDC had issued a travel notice for Romania in November 2016, and it has also posted travel notices for measles in Indonesia and Guinea.
Apr 17 CDC measles travel notice for Belgium
Apr 17 CDC measles travel notice for Italy
Apr 17 CDC measles travel notice for Germany
Apr 7 ECDC measles epidemiologic update

In the United States, measles activity is low so far this year, with only 28 cases reported as of Mar 25, according to an Apr 6 CDC update. In 2014, a record number of US cases—led by a large outbreak in unvaccinated Amish communities in Ohio—were reported since the country eliminated the disease in 2000.

A handful of states have reported recent localized outbreaks, including Minnesota, which recently reported nine cases, most of them involving unvaccinated children in the Minneapolis Somali community, the Minneapolis Star Tribune reported today. California, Michigan, and Nebraska have also reported recent cases.
Apr 6 CDC measles outbreak page
Apr 18 Star Tribune story

 

Nigeria battles meningitis vaccine shortage during outbreak

Nigeria is in the midst of a cerebrospinal meningitis type C outbreak, but a vaccine shortage is limiting the country's efforts to vaccinate its population, The Guardian reported yesterday.

Nigeria needs 1.3 million doses of vaccine against meningitis type C strain, but only 500,000 doses have been delivered to the country. According to the article, the World Health Organization said the International Coordinating Group on Vaccine Provision global emergency stockpile currently has approximately 1.2 million doses of meningitis C–containing vaccines left.

The vaccine is currently being phased out because it is a polysaccharide vaccine, which is slowly being replaced by more effective and long-lasting conjugate vaccines.

According to The Guardian, the number of suspected cases is more than 5,000, with 500 deaths in 19 states.  The outbreak began earlier this year. There are 22 million Nigerians between the ages of 1 and 29, the recommended ages for vaccination against meningitis C. The country is located in Africa's "meningitis belt," which sees several outbreaks of the deadly bacterial infection each year.
Apr 17 Guardian story

 

Pakistan's chikungunya outbreak tops 1,000 cases

The World Health Organization's Regional Office for the Eastern Mediterranean (WHO EMRO) said late last week that Pakistan has now reported 1,018 suspected chikungunya cases in various districts in Karachi division, an increase of 315 cases since its last report on Feb 27.

The cases were reported from Dec 19, 2016 trough Mar 30, WHO EMRO said in an Apr 13 update. Of 157 samples sent to the country's National Institute of Health in Islamabad for laboratory confirmation, 121 tested positive for the mosquito-borne chikungunya virus. No deaths have been reported.

WHO officials are working with Pakistan's health ministry and its partners to respond to the outbreak. District and town health officers have been given instructions on appropriate preventive measures, and pamphlets on how to identify and treat chikungunya have been distributed to healthcare providers.
Apr 13 WHO EMRO update

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