Our weekly wrap-up of antimicrobial stewardship & antimicrobial resistance scans
Study finds variation in superbug colonization tied to close interactions
Close human interaction was highly associated with extended-spectrum beta-lactamase (ESBL)-producing Klebsiella pneumoniae (ESBL-KP) but less so with ESBL-producing Escherichia coli (ESBL-EC) in a nursing home setting, according to a study by French researchers yesterday in PLOS Computational Biology.
In the unique study, the investigators traced possible transmission paths among 329 patients and 263 healthcare workers at a long-term care facility by having them wear sensors. The sensors tracked interactions with patients and hospital staff at closer than 1.5 meters (about 5 feet) every 30 seconds for 4 months. The scientists also swabbed patients weekly to detect carriage of ESBL-producing Enterobacteriaceae. Finally, they used mathematical modeling to assess the effect of several infection-control measures.
The authors found that close interactions were tied to ESBL-KP in 16 of 20 patients (80%), compared with only 54% (19 of 35 patients) for ESBL-EC. Their modeling analysis demonstrated that prevention measures such as increased hand hygiene might reduce the risk. They write that their results are consistent with previous studies investigating the role of patient-to-patient transmission in the spread of Enterobacteriaceae.
The investigators conclude that the findings suggest that contact-prevention strategies—primarily hand hygiene—might help limit transmission of ESBL-KP, but additional steps, such as environmental decontamination or using antibiotics more appropriately, may be necessary to prevent the spread of ESBL-EC.
May 30 PLOS Comput Biol study
Researchers develop highly sensitive rapid susceptibility test
Using optics, Dallas researchers have developed a rapid ultrasensitive detection platform for antimicrobial susceptibility testing that might be especially useful when only a few bacterial or fungal cells are available for analyzing, according to their results, published yesterday in PLOS Biology.
The researchers, from the University of Texas Southwestern Medical Center, call their novel platform rapid ultrasensitive detector (RUSD), and it uses the reflective properties of light as it travels from low- to high-refractive-index media to help measure antimicrobial susceptibility. "RUSD leverages a principle that does not require complex manufacturing, labeling, or processing steps," the scientists write.
The platform can measure susceptibility in as few as 20 bacterial cells or a single fungal cell in the detection volume, which is nearly 10,000 times more sensitive than standard optical density methods. RUSD can measure minimum inhibitory concentrations of commonly used antibiotics against gram-negative and gram-positive bacteria, including Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli, within 2 to 4 hours.
Although the test will require validation, the authors conclude, "We anticipate that the RUSD system will be particularly useful for the cases in which antibiotic susceptibility tests have to be done with a limited number of bacterial cells that are available. Its compatibility with standard antibiotic susceptibility tests, simplicity, and low cost can make RUSD a viable and rapidly deployed diagnostic tool."
May 30 PLOS Biol study
Study finds MRSA transmission varies within and between VA facilities
Originally published by CIDRAP News May 30
A study involving more than 230 Department of Veterans Affairs (VA) hospitals and nursing homes has found significant differences in methicillin-resistant Staphylococcus aureus (MRSA) transmission dynamics within and between the facilities, researchers reported yesterday the journal Epidemics.
In the study, researchers from the University of Utah School of Medicine and the VA Salt Lake City Health Care System set out to evaluate the epidemiology of MRSA infection and transmission in the VA system since the VA's MRSA Prevention Initiative was launched at hospitals in 2007 and extended to nursing homes in 2009. The aim of the study was to better understand variation in MRSA transmission within and between facilities, and to identify trends in the transmission since the initiative was implemented. To do that, they looked at electronic health records for patients admitted to 122 VA hospitals from October 2007 through July 2011, and for patients admitted to 111 VA nursing homes from January 2009 through December 2010.
The analysis showed that the median baseline MRSA transmission rate in VA hospitals was approximately quadruple that in nursing homes and declined in 46% of hospitals compared with 9% of nursing homes, resulting in 43% reduced transmission across hospitals and a 2% increase across nursing homes. First-time admission prevalence was 18.7% in nursing homes compared with 10.5% in hospitals. In addition, the estimated MRSA clearance rate was much lower in nursing homes than in hospitals.
The authors of the study say future research will look at detailed patient and facility characteristics to better understand specific mechanisms and factors that are driving transmission within these facilities.
May 29 Epidemics study
UK pig industry sees decline in antibiotic use
Originally published by CIDRAP News May 30
New data show a third straight year of reduced antibiotic use in pig operations in the United Kingdom, the UK Agriculture and Horticulture Development Board (AHDB) announced today.
Data collected using the electronic medicine book (eMB), a private antibiotic reporting website for UK pig producers, show that antibiotic use in 2018 dropped by 16% from 2017 to 110 milligrams per population correction unit (mg/PCU). Use of critically important antibiotics in pigs fell to 0.06 mg/PCU.
Data taken from eMB represent 89% of all pigs slaughtered in the United Kingdom. The website has a benchmarking function that allows pig producers to compare their antibiotic use with other producers.
"The latest reductions in antibiotic use in the UK pig sector reflect the great efforts of pig producers and their vets to champion responsible antibiotic use," AHDB senior veterinary manager Mandy Nevel, PhD, said in an AHDB press release.
The reductions in antibiotic use bring the UK pig industry closer to the 2020 target of 99 mg/PCU.
May 30 AHDB press release
Study finds prolonged courses of antibiotics common at discharge
Originally published by CIDRAP News May 29
A multicenter study looking at total durations of antibiotic exposure related to hospitalization indicates that more than a third of hospital-related antibiotic exposure occurs after patients are discharged from the hospital, researchers from Duke and the Centers for Disease Control and Prevention (CDC) reported yesterday in Infection Control and Hospital Epidemiology.
For the retrospective study, researchers collected and reviewed electronic data on inpatient and discharge antibiotic prescribing from three pilot hospitals in the southeastern United States from April to September 2016. The primary metric of total duration was defined as the inpatient length of therapy (LOT) plus postdischarge LOT. Postdischarge prescription durations were calculated from electronic discharge prescriptions (e-scripts).
A total of 45,693 admitted patients were evaluated over the 6-month study period. Of these admissions, 23,447 (51%) received inpatient antibiotics and 7,442 (16%) received e-scripts at discharge. E-scripts were prescribed for 348 (5%) admitted patients who did not receive antibiotics as an inpatient. The postdischarge LOT among admissions with discharge antimicrobials was median 8 days, with peaks at 5, 7, 10, and 14 days, and postdischarge days accounted for 38% of antimicrobial exposure days related to hospitalization. And because the estimates of postdischarge antibiotic days were subject to missing data based on avoidance of the electronic system in certain scenarios, the researchers say they could be underestimates.
The authors of the study suggest errors in the ordering process, electronic system defaults for outpatient prescriptions, and diagnostic uncertainty are among the reasons for excessive antibiotic durations on discharge.
"Our findings suggest that prolonged courses of antibiotic therapy are common at discharge and may contribute to unnecessary antimicrobial exposure in patients," they conclude. "ASPs [antibiotic stewardship programs] that target discharge prescription duration and appropriateness have an opportunity to reduce unnecessary antimicrobial use and its resultant harms. These activities should be incorporated to hospital quality improvement initiatives focused at improving safety at transitions of care."
May 28 Infect Control Hosp Epidemiol study
Carbapenemase-producing Enterobacteriaceae cases rise in Hong Kong
Originally published by CIDRAP News May 29
The number of patients in Hong Kong hospitals diagnosed with carbapenemase-producing Enterobacteriaceae (CPE) more than doubled from 2017 to 2018, according to a story yesterday in the South China Morning Post.
Dr. Raymond Lai Wai-man, chief infection control officer for Hong Kong's Hospital Authority, told the paper that the number of inpatients diagnosed with CPE, which is resistant to most antibiotics and can cause severe infections, rose from 473 in 2017 to 972 in 2018. To address the increase in cases and a rise in other multidrug-resistant organisms, Lai said the Authority is introducing a 5-point plan that includes more active screening for patients who've been hospitalized outside Hong Kong in the last 12 months, patients who've spent 14 days or more in the hospital, and patients who have unexplained diarrhea.
Lai said Hong Kong hospitals are also using rapid diagnostic tests to detect the superbug more quickly.
"This allows for quicker medical responses, such as single room isolation in hospitals, with the room wiped clean of bacteria, and nurses dressed in protective gowns and gloves when entering and leaving it," he said.
The Hospital Authority has also implemented an antibiotic stewardship program to monitor antibiotic prescribing at Hong Kong hospitals.
In another story from the same paper, Dr. Ho Pak-Leung, a microbiology professor at Hong Kong University, attributed the surge in CPE infections to overcrowding in the city's public hospitals. "The greatest challenge is the crowded environment in public hospitals, where during peak hours there can be zero distance between beds," Ho told the paper.
May 28 South China Morning Post main story
May 28 South China Morning Post story quoting Ho
Study: Only 58% of STI antimicrobial prescriptions for teens filled
Originally published by CIDRAP News May 29
A research letter yesterday in JAMA Pediatrics says that only 57.7% of antimicrobial drug prescriptions for sexually transmitted infections (STIs) diagnosed in teens visiting emergency departments (EDs) were filled, confirming previous studies that suggest adolescents have an alarmingly low rate of STI treatment adherence.
The retrospective study was based on visits to two pediatric EDs affiliated with Children's National Medical Center in 2016 and 2017. The study included 696 ED visits and 208 teens ages 13 to 19 receiving outpatient prescriptions for antimicrobial treatment for cervicitis or urethritis (31.2%) or pelvic inflammatory disease (68.8%). Of those prescriptions, 57.7% were filled.
The only factor associated with prescription filling was hospital admission (73.7% vs 54.1%; adjusted odds ratio, 2.3; 95% confidence interval, 1.0-5.0). "Admitted patients likely experience more severe symptoms and, thus, may have increased motivation to fill their prescriptions and achieve symptom relief," the authors said.
In a press release on the study, Monika K. Goyal, MD, assistant chief of Children's Division of Emergency Medicine and Trauma Services at Children's National Hospital said the low fill rate may be related to circumstances.
"Teenagers may face a number of hurdles when it comes to STI treatment, including out-of-pocket cost, access to transportation, and confidentiality concerns," she said.
May 28 JAMA Pediatr letter
May 28 Children's National Hospital press release
Acceptance of audit and feedback suggestions linked to better outcomes
Originally published by CIDRAP News May 28
A single-center study conducted at a hospital in Canada has found positive benefits associated with exposure to prospective audit and feedback (PAF), Canadian researchers report in Antimicrobial Resistance and Infection Control.
The retrospective matched cohort study analyzed patients who were assessed during the first year of the hospital's PAF service, in which pharmacists with infectious disease experience review antimicrobial therapy in patients newly admitted to the hospitalist unit. While previous research has shown a reduction in antimicrobial use in the unit after the service was implemented, the researchers wanted to evaluate the impact on clinical outcomes. To do that, they compared 30-day hospital mortality, 30-day post-discharge mortality, and 30-day hospital re-admission rates in those patients compared with a control group of patients admitted prior to initiation of the PAF service.
A total of 348 patients were assessed and received PAF suggestions during the first year of the service, and they were matched with 827 control patients. Of 707 PAF recommendations made, 66% were recorded as fully accepted and 15.8% as partially accepted; 23% of the recommendations were to stop antimicrobial therapy. Unadjusted analysis showed that the composite end point was significantly less likely to occur in the exposed (20.7%) versus the unexposed cohort (28.2%).
In the adjusted analysis, patients in the exposed cohort were 29% less likely to be associated with the composite end point than the control patients (odds ratio [OR], 0.71; 95% confidence interval [CI], 0.52 to 0.97). This observation persisted when only patients with PAF recommendations that were fully or partially accepted were considered (OR, 0.61; 95% CI, 0.43 to 0.87), but not when patients with declined recommendations were analyzed (OR, 1.26; 95% CI, 0.66 to 2.40).
"The positive findings from the current study support the use of PAF which will aid in encouraging hospitalist physicians to apply best practices for optimizing antimicrobial care in their outpatient settings and support outpatient AS [antimicrobial stewardship] systems," the authors of the study write.
May 24 Antimicrob Resist Infect Control study