Superinfections
Joey Sweeney, PharmD, BCPS
Superinfections—infections that occur alongside another infection—are often present in patients who have died from COVID-19. Patients with COVID-19 who develop superinfections also have a higher risk of death than those who do not. In a viewpoint published in Clinical Infectious Diseases, Clancy and Nguyen discuss the risks and possible mechanisms of superinfections developing in patients with COVID-19, the threat of antimicrobial resistance, and the importance of legislative solutions and future studies on the topic.
What do we know?
No studies have been conducted to investigate superinfections in patients with COVID-19. Over the past 6 months of the pandemic, the primary focus for hospitals, clinicians, and other frontline stakeholders has been to take care of patients and staff. Data collection and evaluation via carefully designed prospective studies have taken a backseat in regional responses out of necessity.
But that is not to say that there is a dearth of data. According to Clancy and Nguyen, the most common types of superinfection for ICU patients were bacterial or fungal pneumonia. Specific organisms vary across geography, so it is reasonable to assume that a significant number of superinfections are nosocomial, originating within the hospital.
This may seem counterintuitive on the surface because hospital staff take extreme caution to use appropriate personal protective equipment (PPE) when caring for patients with COVID-19. However, the initial period of this pandemic saw significant supply chain disruptions in PPE across the globe, and the data now being published, which was collected during that period, reflects that disruption.
The authors also propose that immune dysregulation seen in patients with COVID-19 may partially be to blame for the mortality seen with superinfections. Because of increased pro-inflammatory and anti-inflammatory cytokine levels related to COVID-19 disease, increased chance of acquiring a superinfection is possible.
Risk of resistance
Because of these superinfections, empiric antimicrobial therapy with broad-spectrum agents has been widespread, increasing the risk of antimicrobial resistance. More studies are needed to evaluate the impact of this potential increase, but for now, stewardship is the only option for keeping additional resistance at bay.
Historic pressures present in the U.S. antimicrobial pipeline are also contributing to increased resistance. As part of appropriate stewardship, using the narrowest and most cost-effective option is typically the goal. Newer agents are rarely used widely because of cost and the desire to “save” them for when a new resistance surfaces and renders older therapies ineffective.
Also, now that fee-for-service care is all but a memory, hospitals are reimbursed for services at a flat rate related to the diagnosis of the patient. This disincentivizes hospitals to use more expensive options when a less expensive option is available.
Because these market forces are likely to remain in place, legislative solutions may be needed to shore up the antimicrobial pipeline on the basis of it being a good to society. Federal legislators were considering various bills prior to the pandemic. However, the bills are unlikely to be acted upon until 2021 (or later) unless they are paired with a COVID-19–related bill.
Bottom line
Superinfections in COVID-19 patients are often nosocomial in nature. These patients are at greater risk for mortality, and thus physicians often employ empiric antimicrobial therapy, which may lead to increased resistance patterns throughout the world. If governments do not act in a timely manner as the antimicrobial pipeline dries up due to adverse market conditions, we may not have the tools we need to fight future infections once they arrive.