Despite the introduction of seven newly FDA-approved gram-negative antibiotics, specifically designed to combat infections induced by pathogens exhibiting difficult-to-treat resistance, many practitioners and clinicians continue to subscribe to the less efficacious and potentially riskier, generically traditional counterpart antibiotics. This finding was highlighted in a study published in the Annals of Internal Medicine.
A retrospective cohort study was initiated by the National Institutes of Health Antimicrobial Resistance Outcomes Research Initiative. This initiative aimed to elaborate on the consumption pattern of these newer antibiotics, approved post-2014, across a span of 619 hospitals. Data from January 2016 to June 2021 were utilized to showcase the use-patterns of these antibiotics including ceftazidime-avibactam, ceftolozane-tazobactam, meropenem-vaborbactam among others. Notably, a comprehensive statistical model was used to identify factors at the patient and hospital level indicative of a preference for newer generation antibiotics over traditional alternatives.
Across the study’s duration, it was observed that while the application of newer antibiotics increased, clinicians reduced the use of ‘reserve’ antibiotics (e.g. polymyxins, aminoglycosides, tigecycline). Among the newer options, usage of ceftolozane-tazobactam increased most significantly, albeit later declining in 2021 due to shortfalls. Other antibiotics, including meropenem-vaborbactam and cefiderocol, saw slower increases in adoption.
Of the 362,142 inpatient cases across 299 hospitals between January 2019 and June 2021, 0.7% were identified as arising from pathogens showcasing hard-to-treat resistance. Here, newer antibiotics were chosen to treat 58.8% of these cases, with traditional antibiotics prescribed for the remaining 41.5%. These traditional treatments often involved an antibiotic known for its suboptimal safety and/or efficacy profile. Interestingly, the chance of patients with difficult-to-treat bacteremia receiving newer antibiotics was statistically higher, though exceptions were found in cases like do-not-resuscitate status or cases of acute liver failure.
An alarming piece of data revealed that 107 out of 299 hospitals failed to record any cases wherein any next-generation gram-negative antibiotics were applied across the study period. Furthermore, the study found a correlation between the size of the hospital (measured by the number of beds) and the use of newer antibiotics, with smaller hospitals less likely to use them.
It’s crucial to note that while this study unveils important information, it does have its limitations. These include the selection of hospitals analyzed, the potential presence of residual confounding, the absence of results from outsourced susceptibility testing and effects created by the COVID-19 pandemic on antibiotic subscription and resistance rates.
The research concludes that primary care practitioners in hospitals may not be as informed about new antibiotic options as infectious disease specialists and pharmacists are, which may contribute to the prevalence of traditional antibiotics.