Stewardship / Resistance Scan for Mar 12, 2020

News brief

MDR Klebsiella cluster detected in Arizona nursing home

A paper today in the Centers for Disease Control and Prevention's (CDC's) Morbidity and Mortality Weekly Report describes a small cluster of multidrug-resistant Klebsiella pneumoniae detected at an Arizona nursing home.

The cluster was first detected in August 2018 when the Mariposa County Department of Public Health (MCDPH) identified two isolates of carbapenemase-producing K pneumoniae (KPC-KP) in urine samples from two residents of a ventilator-capable unit in a skilled nursing facility. Both residents had urinary tract infections and resided in neighboring rooms. Further analysis of the isolates by the CDC's Antibiotic Resistance Laboratory Network suggested healthcare-associated transmission, and the Arizona Department of Health Services investigated the cluster to prevent additional cases.

Immediate contact screening for KPC-KP colonization among 26 residents who were in the ventilator-capable unit at the same time as the index patients detected KPC-KP isolates in five asymptomatic contacts, three of which had indistinguishable pulsed-field gel electrophoresis patterns from the isolates in the two index patients, a finding that further supported healthcare-associated transmission. A site visit to the facility in September 2018 to observe infection control practices found missed opportunities for hand hygiene before and after physical contact with residents, and lapses in aseptic technique during routine sterile procedures.

Re-screening of the 26 contacts in November 2018 to determine whether MCDPH's recommended control measures were successful in containing the cluster identified three additional cases of KPC-KP colonization.

The authors of the report conclude, "Closer adherence to CDC recommendations that could prevent health care–associated KPC-KP transmission include housing together residents with infection, improving adherence to hand hygiene, using gowns and gloves when interacting with residents who require mechanical ventilation or have tracheostomies, and implementing contact precautions for uncontained body fluids."
Mar 12 MMWR Notes from the field

Pharmacy-led UTI test demonstrates benefits in UK pilot study

A community pharmacy-led test-and-treat service for women with uncomplicated urinary tract (UTI) infections helped support appropriate use of antibiotics and reduced demand on other National Health Services (NHS) resources, English researchers reported today in JAC-Antimicrobial Resistance.

In the pilot study, researchers analyzed data on 764 women who presented to 23 pharmacies with UTI symptoms from December 2018 to April 2019. The test-and-treat service, developed by a team of physicians, pharmacists, and microbiologists, clinically assessed women aged 16 to 64 years for the possibility of uncomplicated UTI, with treatment based on the outcome of a urine dipstick test and National Institute for Health and Care Excellence guidelines. A novel smartphone app provided instructions on use and analysis of the dipstick test and recorded test results. Women were either advised on self-care, supplied with antibiotics, or referred to their general practitioner (GP).

Urine dipstick test results indicated 372 of 496 women (75%) were likely to have a lower UTI, and 360 of 372 of these women (96.8%) purchased antibiotics. Analysis of data indicating what action the women would have taken had the service not been available showed that nearly three-quarters (214/301, 71.1%) would have visited their GP, and more than one-third (116/301, 35.8%) would have attempted self-treatment.

"As pharmacists working within the community become more integrated into primary care networks, there is an opportunity for them to embed services such as this to support self-care and appropriate use of NHS resources," the study authors write. "This would support changing behaviour of patients with UTIs to utilize community pharmacies as the first port of call (i.e. changing to a 'pharmacy first' mentality) and allow for effective triage and treatment within this environment."
Mar 12 JAC-Antimicrobial Resistance study

News Scan for Mar 12, 2020

News brief

Studies show varying flu vaccine effectiveness in Europe

Analysis of six European studies on the 2019/2020 influenza season indicate the interim vaccine effectiveness (VE) against laboratory-confirmed influenza in the primary care setting ranged from 29% to 61% and from 35% to 60% in hospitalized older adults. The results appeared today in Eurosurveillance.

The studies, conducted in 10 countries (Denmark, Spain, Portugal, France, Germany, Romania, Sweden, the Netherlands, Ireland, and the UK) involved a total of 31,537 patients, of which 5,300 were cases (17%) with 5,310 infections. Overall, 84% of confirmed infections were influenza A-positive and 16% were influenza-B positive. Against all subtypes of influenza A among all ages, point estimates for VE ranged from 30% to 60% in primary care and hospitals, and were slightly higher (49% to 62%) in target vaccination groups. Against 2009 H1N1, VE ranged from 48% to 75%. In most studies, the 2019/2020 interim VE against 2009 H1N1 was higher than the 2018/2019 estimates.

Results for VE against H3N2 in the six studies varied widely, ranging from -58% to 57% in primary care and -16% to 60% in hospitals. Against laboratory-confirmed influenza B, VE among all ages ranged from 62% to 83% in primary care settings. The vast majority of circulating influenza B belonged to the B/Victoria lineage, which was the lineage included in the trivalent vaccine but of another subgroup.

For adults over 65, the six studies had VE point estimates of 43% to 66% across all settings.

The authors of the study say VE and antigenic studies at the end of the 2019/2020 season will help explain the age-, subtype-, and study-specific differences seen in the interim results.
Mar 12 Eurosurveill study

Study: 3-drug antimalarial regimens effective, could delay resistance

Adding a third drug to the typical two-drug antimalarial regimen might be an effective strategy in regions where drug resistance is widespread, according to study published yesterday in The Lancet.

Led by researchers at Mahidol University in Bangkok, the multicenter, open-label, randomized clinical trial found that triple artemisinin-based combination therapies (TACTs) could effectively treat malaria caused by Plasmodium falciparum and delay the development of antimalarial drug resistance.

The investigators randomly assigned 1,110 patients at 18 hospitals and clinics in eight countries to either a two-drug or three-drug combination, depending on their location, from Aug 7, 2015, to Feb 8, 2018. Median age was 23 years, and 78% of patients were male. The patients were followed weekly for 42 days, when their response to the drugs was determined via polymerase chain reaction.

The researchers found that the combinations of dihydroartemisinin–piperaquine plus mefloquine and artemether–lumefantrine plus amodiaquine, both of which are TACTs, were effective, safe, and well-tolerated.

Typical antimalarial regimens combine the drug artemisinin, which quickly kills the parasites, with a slower-acting drug such as mefloquine or piperaquine to eliminate any remaining parasites and oppose resistance to artemisinin. Resistance to artemisinin is common in parts of Southeast Asia, where malaria is widespread, which delays elimination of the parasites. Also, the emergence of resistance to mefloquine and piperaquine has become a pressing concern.

The study found that, in areas with widespread resistance to artemisinin, 42-day responses were 98% (95% confidence interval [CI], 94 to 100) with dihydroartemisinin–piperaquine plus mefloquine, compared with 48% (95% CI, 39 to 56) with dihydroartemisinin–piperaquine.

In a commentary in the same issue, Philip Rosenthal, MD, of the University of California at San Francisco, said the results suggest that TACTs might replace ACTs for a time in some areas. "This study offers promise for TACTs in regions with artemisinin resistance, but whether we should implement TACTs in other areas is uncertain," he said. "In any event, TACTs should be seen as a stopgap; novel combination therapies to treat malaria are greatly needed."
Mar 11 Lancet study
Mar 11 Lancet commentary