Codex Alimentarius to revise guidelines on AMR in the food chain
Members of the World Health Organization's (WHO's) food standards–setting body, the Codex Alimentarius Commission, agreed yesterday to update guidelines aimed at reducing antimicrobial resistance along the food chain.
The group, which is meeting this week in Geneva to discuss adoption of several new standards on food safety, agreed to revise and broaden the scope of the Code of Practice to Minimize and Contain Antimicrobial Resistance, a 2005 document that provides guidance for the responsible and prudent use of antimicrobials in food-producing animals.
The revisions will include developing a risk-based guidance on the management of foodborne antimicrobial resistance, with greater focus on the risk to human health associated with the presence of antimicrobial resistant organisms in the food chain. The updated code will also address strategies to reduce the need for antimicrobials in food-producing animals.
The commission also agreed to develop guidance on the design and implementation of integrated surveillance of foodborne antimicrobial resistance along the food chain. The hope is that a harmonized approach to surveillance will facilitate the exchange and analysis of data from different countries.
Jul 18 WHO food safety update
Stewardship linked to better outcomes in patients with skin wounds
Appropriate use of antimicrobial agents under the direction of an antimicrobial stewardship program (ASP) can lead to improved outcomes for patients with skin and soft-tissue infections (SSTIs), researchers reported yesterday in the American Journal of Infection Control.
In the quasi-experimental study conducted at three hospitals from a single health system in Des Moines, Iowa, researchers collected prospective and historic control data for the 7-month ASP intervention period (January through July 2012) and a 7-month period from the prior year. The ASP intervention was centered around a new SSTI evidence-based treatment algorithm, passive provider education about the treatment algorithm, and additional education (including phone calls and notes from the medical record) targeting physicians not adhering to the algorithm.
Of the 412 patient charts that were reviewed across the two 7-month periods, a total of 76 and 86 patients were found eligible from the historic and prospective time periods, respectively. The outcomes revealed the proportion of appropriate antibiotic usage in the intervention period was nearly twice that of the historic period, and that patients in the intervention period had a lower median number of days of antipseudomonal antibiotic use, a reduced median number of days from the initial intravenous antibiotic therapy to oral conversion, and fewer SSTI treatment complications.
The authors note, however, that there were some unexpected results. The median length of hospital stays in both periods remained consistent, and there was no significant decrease in the duration of antibiotic therapy in the intervention period. In addition, quicker transition from intravenous to oral antibiotic therapy was not associated with rapid improvement in patients' clinical appearance.
"Although additional positive outcomes may have been expected, it remains apparent that quality improvements can be obtained when guided by stewardship," the authors write.
Jul 18 Am J Infect Control study
Study shows high rate of transfer of MDR plasmid in chicken gut model
UK scientists have demonstrated that the transfer of a multidrug-resistant (MDR) plasmid from Salmonella to Escherichia coli occurs at a high rate in the simulated gut of a chicken, even in the absence of antibiotics, according to a study yesterday in mBio.
Plasmids are highly mobile pieces of DNA that can be shared within and between different bacterial species, enhancing their ability to spread drug resistance. The researchers used an in vitrochemostat system to approximate the chicken cecal microbiota, simulate colonization by an MDR Salmonella pathogen, and examine the dynamics of transfer of its MDR plasmid harboring several genes, including the extended-spectrum beta-lactamase blaCTX-M1. They also assessed the impact of cefotaxime administration on plasmid transfer and microbial diversity.
They demonstrated via polymerase chain reaction testing and whole-genome sequencing that MDR plasmid transfer occurred from Salmonella to E coli isolates. And it occurred to seven E coli sequence types at high rates, even in the absence of cefotaxime usage, with resistant strains isolated within 3 days from the start of the experiment.
The authors concluded, "We show that transfer of a multidrug-resistant plasmid from the zoonotic pathogen Salmonella to commensal Escherichia coli occurs at a high rate, even in the absence of antibiotic administration. Our work demonstrates that the in vitro gut model provides a powerful screening tool that can be used to assess and refine interventions that mitigate the spread of antibiotic resistance in the gut before undertaking animal studies."
Jul 18 mBio study
Several antibiotics linked to higher rates of congenital defects
A large study out of Quebec found that in utero exposure to clindamycin, doxycycline, quinolones, and several other antibiotics was linked to organ-specific malformations in babies, while other antibiotics were not associated with major congenital malformations (MCMs).
Writing in the British Journal of Clinical Pharmacology, the investigators analyzed data on 139,938 infants born in Quebec from 1998 through 2008. They assessed antibiotic exposure in the first trimester of pregnancy and identified congenital malformations in the first year of life.
After adjusting for potential confounders, they determined that clindamycin exposure was associated with a 34% increased risk of MCMs, a 67% added risk of musculoskeletal system malformations, and an 81% rise in ventricular or atrial septal defects.
Doxycycline exposure more than doubled the risk of circulatory system malformation, cardiac malformations, and ventricular/atrial septal defect. They also noted one MCM each with quinolone, moxifloxacin, ofloxacin, macrolide, erythromycin, and phenoxymethylpenicillin.
The researchers found no link to MCMs with amoxicillin, cephalosporins, and nitrofurantoin. The same group in May reported higher rates of miscarriage tied to antibiotic use.
Jul 19 Br J Clin Pharmacol study
May 2 CIDRAP News story "Antibiotics in pregnancy tied to higher miscarriage risk"
