Our weekly wrap-up of antimicrobial stewardship & antimicrobial resistance scans

Study links antibiotic use with onset of rheumatoid arthritis

A new study in BMC Medicine suggests a possible link between antibiotic use and the onset of rheumatoid arthritis (RA).

In a nested case-control study conducted using data from a large database of UK primary care medical records, a team of British researchers identified 22,677 patients with a diagnosis of RA from 1990 through 2017 and matched them with 90,013 control patients. Conditional logistic regression was used to examine previous antibiotic prescriptions and RA onset after controlling for confounding factors.

The analysis found that the odds of developing RA were 60% higher in those exposed to antibiotics than in those not exposed (odds ratio [OR], 1.60; 95% confidence interval [CI], 1.51 to 1.68). A dose- or frequency-dependent association was observed between the number of previous antibiotic prescriptions and RA, with the magnitude of association with RA rising with an increasing number of unique antibiotic prescriptions. The odds of RA were also higher in those last exposed to antibiotics 1 to 2 years before the index date than in those exposed 5 to 10 years before the index date.

All classes of antibiotics were associated with higher odds of RA, with bactericidal antibiotics carrying higher risk than bacteriostatic (45% vs 31%). RA cases were more likely to have a record of infection before their diagnosis, with increased odds of RA among those with a previous infection ranging from 7% for urinary tract infections to 37% for those with lower respiratory tract infections. In addition, those with antibiotic-treated upper respiratory tract infections were more likely to be RA cases. Antifungal (OR, 1.27; 95% CI 1.20 to 1.35) and antiviral (OR, 1.19; 95% CI 1.14 to 1.24) prescriptions were also associated with increased odds of RA.

The authors of the study suggest the association between RA and antibiotic use could be linked to disruption of the gut microbiota, but they caution that more research is needed, as it is unclear at this point whether the major driver is antibiotic use or the underlying infection. "These observations require extensive additional studies to (both case-controlled and mechanistic) to determine direct causation," they write.
Aug 7 BMC Med study

Italian hospital study finds improved use of pre-surgery antibiotics

Originally published by CIDRAP News Aug 8

A surveillance study of Italian hospitals found improved compliance with surgical antimicrobial prophylaxis (SAP) guidelines over a 6-year period, Italian researchers reported yesterday in the American Journal of Infection Control.

The study by researchers from the University of Turin was conducted in 42 hospitals participating in a national surveillance system for surgical site infections (SSIs). According to data from the European Centre for Disease Prevention and Control, SAP for the prevention of SSIs accounts for 17.4% of antimicrobial use in Italy, but compliance with national SAP guidelines varies widely, and there are concerns that Italian physicians do not routinely follow recommendations. The investigators evaluated data from 2012 through 2017 to assess the prescribing practices and SAP compliance with Italian national guidelines and the association between SAP compliance and SSI risk.

A total of 24,861 surgical procedures were monitored over the study period, and a total of 827 SSIs occurred. Overall compliance with SAP guidelines was achieved in 35.41% of procedures in 2012 and increased to 60.79% of procedures in 2017, and the risk ratios (RRs) for appropriate SAP increased by 22% each year, with significant increasing trends over time found for overall compliance, timing, and duration. Adequate antibiotic choice (RR, 0.57; 95% confidence interval [CI], 0.5 to 0.65), duration of administration (RR, 0.51; 95% CI 0.45 to 0.57), and overall compliance (RR, 0.65; 95% CI, 0.59 to 0.72) were all associated with a significantly reduced SSI risk.

The authors of the study conclude, "Interventions to improve SAP compliance with national guidelines could significantly contribute to reducing antimicrobial resistance, both by reducing the burden of HCAIs [healthcare associated infections] and by promoting more prudent use of antimicrobials."
Aug 7 Am J Infect Control abstract 

Multidrug-resistant bacteria found in urban rats

Originally published by CIDRAP News Aug 8

A study today in Eurosurveillance by German and Austrian researchers suggests urban rats could be potential spreaders of multidrug-resistant bacteria.

The researchers looked for the presence of antimicrobial-resistant bacteria in 62 urban brown rats captured in Vienna in 2016 and 2017. They were looking specifically to see whether the rats carry extended-spectrum beta-lactamase-producing Enterobacteriaceae, fluoroquinolone-resistant Enterobacteriaceae, and methicillin-resistant Staphylococcus spp (MRS). Pharyngeal and nasal samples were collected from the animals, and the researchers characterized the isolates using microbiologic and genetic methods.

Eight multidrug-resistant Escherichia coli and two extensively drug-resistant New Delhi metallo-beta-lactamase-1 (NDM-1)-producing Enterobacter xiangfangensis ST114 (members of the Enterobacter cloacae complex) were isolated from 9 of 62 rats. Nine of the Enterobacteriaceae isolates carried the blaCTX-M gene and one carried the plasmid-encoded ampC gene. Forty-four MRS, belonging to seven different staphylococcal species, were isolated from 37 of 62 rats. The overall presence of antimicrobial-resistant bacteria in the rats was 62.9%.

"Although the interaction between urban wildlife reservoirs of AMR [antimicrobial resistance] and human health risk remains unclear, the overall prevalence of AMR we observed in the sampled rats is of concern," the authors of the study write, noting that several of the rats colonized with multidrug-resistant isolates were captured in a neglected garden used by the homeless. "This particular situation enhances the risk of spillover of antimicrobial-resistant bacteria."

The authors say the results stress the importance of urban wildlife species as bio-indicators for AMR surveillance programs in urban ecosystems.
Aug 8 Eurosurveill study

Vancomycin-resistant Staph found in Egyptian camels, abbatoir workers

Originally published by CIDRAP News Aug 7

An investigation in Cairo has identified vancomycin-resistant Staphylococcus aureus (VRSA) in camel meat samples and slaughterhouse workers, Egyptian researchers reported in Antimicrobial Resistance and Infection Control.

The researchers collected 200 meat samples from dromedary camel carcasses at three different abattoirs in Cairo and hand swabs from 20 adult male slaughterhouse workers. S aureus was isolated from 29 of the camel meat samples (14.5%) and 11 of the hand swabs (55%). Of the 40 S aureus isolates tested for resistance, 14 (35%) were resistant to vancomycin, with 27.6% of meat samples (8/29) and 54.5% of hand swabs (6/11) showing resistance. Additionally, all VRSA isolates were also classified as methicillin-resistant.

Molecular analysis indicated that all 14 VRSA isolates harbored both vanA and vanB genes, and whole-genome sequencing of four of the isolates (2 from camels, 2 from humans) revealed that the vanA sequences were identical to each other, suggesting potential zoonotic transmission.

"Our research is the first in Egypt to report VRSA in camels, and we urge further comprehensive molecular epidemiological surveillance studies on the extent and potential zoonotic transmission of VRSA in livestock animals," the authors of the study write. "Urgent interventions to control the transmission of these antibiotic-resistant organisms in abattoirs are needed."
Aug 5 Antimicrob Resist Infect Control study

Study finds antibiotics used for noninfectious indications in kids

Originally published by CIDRAP News Aug 6

A point-prevalence study of US children's hospitals found that 1.7% of hospitalized pediatric patients received at least one antibiotic for a noninfectious indication, a team of US researchers reported in the Journal of the Pediatric Infectious Diseases Society.

In the cross-sectional study of 32 academic tertiary-care pediatric inpatient facilities, conducted from June 2016 through December 2017, researchers reviewed a total of 35,378 patient records and identified 13,215 patients (37.3%) who received at least one antimicrobial agent. Among those who received an antibiotic were 627 patients (1.7% of all admitted patients) who had a noninfectious indication. Antibiotic use for a noninfectious indication among patients who received an antibiotic ranged from 0% to 10.1% across the hospitals.

Of the 29 unique antibiotics used for a noninfectious indication, the most commonly prescribed antibiotics were erythromycin (63.1%), azithromycin (19.9%), amoxicillin-clavulanate (5.5%), and metronidazole (5.2%). The most common reason for antibiotic use was gastrointestinal prokinesis (67.4%), followed by use for anti-inflammatory properties (17.5%) and small-bowel bacterial overgrowth (5.5%).

The authors of the study say the lack of national consensus guidelines for aiding decisions about when to use antibiotics for noninfectious indications makes it difficult to assess whether these prescriptions were appropriate. They also note that data are limited on whether these agents are effective for treating the noninfectious indications documented in the study or on how their use in children affects the intestinal microbiome.

They conclude, "Multidisciplinary efforts should be taken to carefully analyze the effectiveness of these agents for their intended purpose while considering the effect on the pediatric microbiome, the harms of antimicrobials, and the potential societal effects of antimicrobial resistance within the community. Antimicrobial stewards should partner with those in other disciplines to understand and improve research into these longer-term harms."
Jul 31 J Pediatric Infect Dis Soc study