News Scan for Oct 10, 2017

News brief

Local chikungunya cases rise in Italy, France

Italy's chikungunya outbreak has expanded to a second region, and the total number of suspected or confirmed cases has climbed to 298 as of Oct 4, a rise of 115 cases from World Health Organization's update at the end of September.

In an updated risk assessment yesterday from the European Centre for Disease Prevention and Control (ECDC), officials said a cluster of illnesses has been reported in the city of Guardavalle Marina, located in Calabria region, about 300 miles southeast of Lazio region, where earlier clusters were reported.

So far, 239 confirmed or probable local chikungunya cases have been reported in Lazio region, and 55 (including 6 confirmed illnesses) have been reported in Calabria region. Also, several probable and confirmed cases with links to three cities (Anzio, Rome, and Guardaville Marina) in two affected regions have been reported from other parts of Italy, as well as France and Germany, pushing the outbreak total to 298.

The virus circulating in Anzio is similar to 2016 chikungunya viruses from Pakistan and India; sequencing of the strain from Calabria region is under way.

Meanwhile, a local outbreak in France has sickened 17 people so far, part of activity involving two epidemiologically linked clusters, one in Cannet-des-Maures in the south and the other in nearby Taradeau. The chikungunya strain in France is related to a Central African sublineage.

The ECDC said local transmission in France and Italy in warmer months in areas where Aedes albopictus are established is not unexpected. The ECDC said the likelihood of further spread in Italy is moderate, and that more cases are expected. However, environmental conditions over the next several weeks will become less suitable for the mosquitoes that spread the virus.
Oct 9 ECDC risk assessment


Study: ring vaccination strategy successful in rural settings

Ring vaccination, a strategy that vaccinates a ring of close contacts in a disease outbreak, was successful in preventing wider spread of Ebola in Guinea after the country's final case was detected in March 2016. The research on the vaccination practice and the results were published yesterday in The Lancet Infectious Diseases.

In 2016, Guinea reported a flare up of the ongoing Ebola outbreak in two confirmed cases, and the unlicensed rVSV-ZEBOV vaccine was used for the first time in an outbreak setting to contain the spread of the virus. From Mar 17 to Apr 21, 2016, 1,510 people were vaccinated in four rings. The vaccine recipients included 303 children ages 6 to 17 years and 307 healthcare workers and first responders.

No secondary cases of Ebola were reported in those who received rVSV-ZEBOV. Participants were checked for adverse reactions 30 minutes after receiving the vaccine, and again each week basis for 3 weeks. No severe adverse events were reported.

"Our results show that a ring vaccination strategy can be rapidly and effectively implemented at scale in response to Ebola virus disease outbreaks in rural settings and across borders," the authors concluded.
Oct 9 Lancet Infect Dis study


IV flu antivirals reduce use of ICU, mechanical ventilation

New Canadian research presented at IDWeek 2017 last week showed that intravenous administration of influenza antivirals cut the risk of mechanical ventilation (MV) and reduced intensive care unit (ICU) admissions, according to an MPR story.

Each year, influenza causes approximately 12,200 hospitalizations and 3,500 deaths in Canada. Researchers used data from the Serious Outcomes Surveillance (SOS) Network of the Canadian Immunization Research Network (CIRN), to track the outcomes of hospitalized patients who tested positive for influenza from 2011 to 2014. A total of 4,861 patients were included in the study. Of those, 16% were admitted to the ICU, 11% required MV, and 9% died. 

According to the researchers, the odds ratio for ICU or MV among patients who received antiviral use was 0.10.

"Treatment with antivirals was associated with a significant reduction in admission to ICU and/or need for MV (odds ratio [OR] 1.10, 95% CI: 0.08–0.13; P < 0.001) but was not significantly associated with a reduction in death irrespective of the time between symptom onset and start of antivirals," said Zach Shaffelburg, BSc, from the Canadian Center for Vaccinology.
Oct 6 MPR report

Stewardship / Resistance Scan for Oct 10, 2017

News brief

Studies describe MCR-1 cases, prevalence in US

Three studies presented at IDWeek 2017 in San Diego last week focused on the emerging colistin-resistance gene MCR-1 in the United States.

Two of the abstracts were case reports. In one, investigators from the Centers for Disease Control and Prevention (CDC) and the Connecticut Department of Health reported that MCR-1 was isolated from two Connecticut residents—an adult and an unrelated child—who had diarrhea. The gene was identified in an Escherichia coli isolate from the child and a Salmonella Enteritidis isolate from the adult, and the plasmids containing the gene were identical by DNA sequencing. Both patients reported recent travel to the Dominican Republic.

In the other case report, researchers from the University of Michigan Medical School and the Michigan Department of Health and Human Services described three patients from a single health system who had travel-associated colistin-resistant E coli. The presence of the MCR-1 gene in the patients' urine was confirmed by polymerase chain reaction testing. All isolates were carbapenem susceptible. No healthcare-associated epidemiologic links were identified, but all three patients had travelled internationally within the prior 6 months—one to Kenya and China, one to Lebanon, and one to Mexico.

The authors of the case reports conclude that increased surveillance is needed to understand the scope and risk factors associated with MCR-1–mediated resistance, with a particular focus on the role of international travel.

In the third abstract, investigators from the CDC and state health departments in Virginia, Tennessee, Minnesota, and Connecticut screened 70,000 nontyphoidal Salmonella isolates from humans, retail meat, and food animals for the presence of MCR-1. No Salmonella isolates with MCR-1 were found in retail meat and food animals, but four human cases of Salmonella with MCR-1 were identified: Salmonella Corvallis in an 18-year-old man from Tennessee, Salmonella Enteritidis in a 55-year-old woman from Connecticut and a 47-year-old man from Minnesota, and Salmonella Typhimurium in a 57-year-old woman from Virginia. All patients had traveled internationally in the 10 days prior to illness onset.

The researchers say the absence of MCR-1 in the retail meat and food animals is likely because colistin has not been used in food animal production in the United States.

MCR-1 was first identified in E coli samples from pigs, pork products, and humans in China in 2015. Since then, it has been detected in human, animal, food, and environmental samples in more than 30 countries.
Oct 5 IDWeek abstract 383
Oct 5 IDWeek abstract 384
Oct 5 IDWeek abstract 324


Chinese study finds 6.2% prevalence of MCR-1 in patients' fecal samples

Of more than 8,000 fecal samples collected from inpatients and outpatients in China in recent years, 6.2% were MCR-1–positive, and more than a third of the positive samples were resistant to third-generation cephalosporins, researchers reported today in Clinical Infectious Diseases.

The investigators analyzed 8,022 samples collected from April 2011 through March 2016 from three hospitals in Guangzhou, a port city of 14 million people. Of the total samples, 497 (6.2%) were MCR-1–positive, and 182 (2.3%) were Enterobacteriaceae that harbored MCR-1 resistant to third-generation cephalosporins, a worrisome combination. Those Enterobacteriaceae—most commonly Escherichia coli—were often multidrug resistant.

The researchers also found that the presence of MCR-1 increased from 0% to 31% over the course of the study. The MCR-1 Enterobacteriaceae resistant to third-generation cephalosporins did not appear until recent years.

Whole-genome sequencing revealed similarity with published MCR-1 plasmid sequences and pointed to spread among animal and human reservoirs. The authors concluded, "The high prevalence of mcr-1 in multidrug-resistant E. coli colonizing humans is a clinical threat; diverse genetic mechanisms (strains/plasmids/insertion sequences) have contributed to the dissemination of mcr-1, and will facilitate its persistence."
Oct 10 Clin Infect Dis abstract


Widespread MDRO carriage found in nursing homes, long-term care

Two point-prevalence studies conducted in southern California suggest that multidrug-resistant organisms (MDROs) are prevalent in the region's nursing homes and long-term care facilities.

In a study conducted as part of the CDC's SHIELD (Shared Healthcare Intervention to Eliminate Life-threatening Dissemination of MDROs) Orange County project, investigators performed point-prevalence screening on adult patients in 38 facilities (17 hospitals, 18 nursing homes, and 3 long-term acute care facilities) from September 2016 through April 2017.

They screened for methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE), extended-spectrum beta-lactamase (ESBL), and carbapenem-resistant Enterobacteriaceae (CRE) using nares, skin, and peri-rectal swabs. All hospital patients were under contact precautions.

The overall prevalence of any MDRO among patients was 64% in nursing homes, 80% in long-term acute care facilities, and 64% in hospitals. MRSA infections were most common in nursing homes (42%) and hospitals (37%), while VRE infections were most common in long-term acute-care facilities (55%). Known MDRO patients also harbored another MDRO 49%, 63%, and 34% of the time in nursing homes, long-term acute care facilities, and hospitals, respectively. In the long-term acute care facilities, MDRO point prevalence was 38% higher than the usual admission prevalence.
Oct 6 IDWeek oral abstract 1712

In the other study, investigators conducted a baseline point-prevalence study in fall 2016 of MDRO colonization in residents of 28 southern California nursing homes participating in a decolonization trial. A total of 2,797 swabs were obtained from 1,400 residents. Nasal swabs were processed for MRSA, and skin swabs were processed for MRSA, VRE, ESBL, and CRE. In addition, environmental swabs were collected from high-touch objects in resident rooms and common areas.

Overall, 48.6% of residents harbored MDROs, mainly MRSA (37%) and ESBL (16%). Resident MDRO status, however, was known for only 11% of MRSA and 18% of ESBL carriers, while only 4% of VRE and none of the CRE carriers were known to harbor the organisms. Bedbound residents were more likely to be MDRO colonized than ambulatory residents (58.7% vs. 45.7%). Environmental swabbing revealed that 93% of common area objects (nursing stations, hand rails, and drinking fountains) and 74% of resident room objects (bedside tables, bedrails, and door knobs) harbored an MDRO.

The authors of the two studies, which were presented at IDWeek 2017 in San Diego late last week, say the findings indicate that MDROs are as widespread in highly interconnected nursing homes and long-term acute care facilities as they are in hospitals, and that strategies to reduce MDRO colonization and transmission in these settings should be part of regional MDRO prevention efforts.
Oct 6 IDWeek oral abstract 1696


Gram-negative bacteria common in resistant infection in African kids

Though recent and high-quality data are lacking, a meta-analysis of antimicrobial resistance in children in sub-Saharan Africa found that gram-negative organisms were the predominant cause of early-onset neonatal sepsis and were also responsible for a high proportion of infections among older children, according to a study yesterday in The Lancet Infectious Diseases.

The UK and Australian researchers systematically reviewed 1,075 studies on antimicrobial resistance in African children and included 18 in their final analysis and provided data on 67,451 isolates of pathogenic bacteria.

They reported that gram-negative organisms were the predominant cause of early-onset neonatal sepsis, with a high prevalence of extended-spectrum beta-lactamase-producing organisms. In older children, gram-positive bacteria were responsible for a high percentage of infections, with high prevalence of non-susceptibility to treatment advocated by World Health Organization therapeutic guidelines.

The authors conclude, "There are few up-to-date or representative studies given the magnitude of the problem of antimicrobial resistance, especially regarding community-acquired infections. Research should focus on differentiating resistance in community-acquired versus hospital-acquired infections, implementation of standardised reporting systems, and pragmatic clinical trials to assess the efficacy of alternative treatment regimens."
Oct 9 Lancet Infect Dis study

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