Our weekly wrap-up of antimicrobial stewardship & antimicrobial resistance scans
Beta-lactam allergy test shown to improve antibiotic stewardship
The use of beta-lactam allergy skin testing (BLAST) at the point of care in hospital antimicrobial stewardship programs (ASPs) resulted in greater use of preferred beta-lactam therapy without increasing the risk of adverse drug reactions, according to a study yesterday in Clinical Infectious Diseases.
Researchers in Toronto conducted a prospective study on the use of point-of-care BLAST as part of ASPs in three hospitals. Of 827 patients with reported beta-lactam allergy over the 15-month study period, beta-lactam therapy was preferred in 632 (76%).
The investigators reported that 50% (124/246) received preferred beta-lactam therapy based on history at baseline, but the percent rose to 60% (232/386) during the intervention period and to 81% (313/386) once BLAST was instituted, without any increase in adverse events. After adjusting for multiple patient variables, the researchers determined that BLAST was associated with 4.5-fold greater odds of receiving preferred beta-lactam therapy.
The authors note, "Longer term studies are needed to better assess the safety and clinical impact of this ASP intervention."
Jun 1 Clin Infect Dis study
Study describes spread of livestock-associated MRSA in Denmark
Originally published by CIDRAP News May 31
Livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) appears to be spreading further into the community and healthcare settings in Denmark, researchers reported yesterday in Clinical Infectious Diseases.
In the study, researchers evaluated data on all Danish patients who were registered as having had an episode of MRSA bloodstream infection (BSI) or skin and soft tissue infection (SSTI) from 2010 through 2015. Using molecular sequencing tests, they set out to determine how many were caused by LA-MRSA clonal complex 398 (CC398), which has been causing an increasing number of human infections in Denmark and other European countries with industrial pig production. While SSTIs caused by LA-MRSA CC398 have been studied and are mainly associated with livestock workers, less is known about the strain's impact on BSIs.
The researchers also wanted to compare LA-MRSA CC398 BSI cases to SSTI cases caused by the strain and to BSI cases caused by other strains of MRSA, and to determine the phylogenetic relationship among LA-MRSA CC398 isolates from pigs and from human infections.
Overall, LA-MRSA CC398 accounted for 17 cases of BSI, 700 cases of SSTI, and 76 cases with other infections from 2010 through 2015. The number BSIs and SSTIs caused by the strain increased over the years and peaked in 2014, accounting for 16% (7 of 44) of BSIs and 21% (211 of 985) of SSTIs. Of the total LA-MRSA CC398 SSTIs, 32% (221 of 700) occurred in people with no livestock contact, while 59% (10 of 17) patients with LA-MRSA CC398 BSIs had no contact with livestock, although they tended to live in rural areas.
In addition, the researchers also found that LA-MRSA CC398 appears to be just as capable of causing serious illness in elderly and immunocompromised people, and that most of the BSI and SSTI isolates were closely related to Danish LA-MRSA CC398 isolates from Danish pigs, a finding that suggests zoonotic transmission from an expanding pig reservoir.
Even though Denmark has low-endemic levels of MRSA, the authors warn that the number of serious infections and deaths will likely increase if LA-MRSA CC398 spreads further into the general population.
May 30 Clin Infect Dis abstract
Maryland law ends routine use of antibiotics in healthy farm animals
Originally published by CIDRAP News May 31
Maryland has become the second state in the nation to prohibit the routine use of antibiotics in healthy livestock and poultry.
Reuters reports that Maryland's Keep Antibiotics Effective Act will take effect on Oct 1 and that farmers in the state will have until Jan 1, 2018 to comply with the law. Maryland's governor declined to sign or veto the bill last week.
Under the new law, farmers in the state will only be allowed to use antibiotics to treat sick animals or to control verified disease outbreaks. California passed a similar law in 2015 that will go into effect next year. Both laws go beyond the US Food and Drug Administration's guidelines, which aim to prevent the use of medically important antibiotics for growth promotion in food-producing animals but do not end their use in disease prevention. Critics have said the FDA policy doesn't go far enough.
"Maryland’s action to protect antibiotics sets the example for other states to follow," Emily Scarr, director of the advocacy group Maryland PIRG, which supported the law, said in a press release. "We hope more states, retailers, and producers will now become inspired to protect public health by taking action to restrict use of antibiotics on farms."
May 30 Reuters article
May 30 U.S. PIRG press release
Gonorrhea isolates from Hawaii outbreak show high resistance profile
Originally published by CIDRAP News May 30
A new report in Clinical Infectious Diseases is providing some additional detail on a cluster of genetically related Neisseria gonorrhea isolates with high-level azithromycin resistance and decreased ceftriaxone susceptibility previously detected in Hawaii.
After demonstrating elevated minimum inhibitory concentrations (MICs) for azithromycin and ceftriaxone in antimicrobial susceptibility testing by the Hawaii Department of Health, the eight N gonorrhea isolates collected from seven patients on Oahu from April 2016 through May 2016 were sent to the University of Washington and the US Centers for Disease Control and Prevention (CDC) for further testing. That testing confirmed that all isolates showed high-level azithromycin resistance and five had reduced susceptibility to ceftriaxone. All isolates were also beta-lactam positive and resistant to penicillin, tetracycline, and ciprofloxacin. Genomic analysis revealed that the isolates were genetically related
The seven patients included six males and one female. All patients were successfully treated. Eight recent unique partners were reported by the patients, with two male patients identifying the same female sex worker from a Honolulu massage parlor as a recent contact. Only one of the eight partners was diagnosed and treated for gonorrhea.
The cases were first reported by the CDC in September 2016.
The authors of the study say they believe these are the first gonococcal isolates identified in the United States with both high-level azithromycin resistance and reduced ceftriaxone susceptibility. Because gonorrhea has developed resistance to previously recommended antimicrobials, the CDC currently recommends only the combination of ceftriaxone and azithromycin as the standard treatment for the sexually transmitted disease. The concern is that widespread transmission of such strains could complicate treatment.
The authors warn that clinicians should be on high alert so that any suspected gonorrhea treatment failures can be identified and reported to local health departments and the CDC.
"Rapid detection and effective treatment may prevent sequelae, allow partners to be identified and treated in a timely manner, and prevent or slow further transmission of resistant strains," they write.
May 26 Clin Infect Dis abstract
Sep 21, 2016, CIDRAP News story
Tests find cleaning-disinfection products work well on MDR pathogens
Originally published by CIDRAP News May 30
A study that compared seven different commercial products for cleaning and disinfecting hospital rooms found that nearly all were effective against three multidrug-resistant (MDR) outbreak pathogens, except for one that contained hydrogen peroxide.
Dutch researchers focused on three bacterial strains known to cause MDR outbreaks at hospitals in the Netherlands: vancomycin-resistant enterococci (VRE), Klebsiella pneumoniae OXA-48, and Acinetobacter baumannii. The team published its findings yesterday in the American Journal of Infection Control.
Each ready-to-use cleaning and disinfecting product had a different active ingredient, and testing involved both wiping and spraying. Researchers assessed how well the products reduced microbial count and protein on tiles that were similar to those found in hospital settings.
All products reduced microbial count by more than 5 log10 with 5-minute exposure times, except for a hydrogen peroxide–based spray, which showed lower reduction against VRE. For the six other products, researchers saw no significant differences in bacterial load reduction between use of a wipe or a spray.
May 29 Am J Infect Control study