Infection
Doxycycline lowers C. diff icile risk in patients with pneumonia
Nov
November 04, 2023
2 min read
Key takeaways:
- Patients with community-acquired pneumonia faced a lower risk for C. difficile when prescribed doxycycline.
- The risk for patients with a documented C. difficile infection in the prior year was nearly halved.
Doxycycline reduced the risk for Clostridioides difficile infection by almost half compared with azithromycin among patients hospitalized with community-acquire pneumonia who had a C. difficile infection in the past year, a study found.
According to the authors of the study, the Infectious Disease Society of America recommends an empiric beta-lactam antibiotic regimen for common pathogens associated with community acquired pneumonia (CAP), “in addition to a macrolide for atypical bacterial coverage.”
“If a contraindication to a macrolide exists, such as an allergy or an elevated QTc interval, doxycycline is recommended as an alternative,” they wrote in the American Journal of Infection Control.
Although C. difficile infection (CDI) is rare, people are seven to 10 times more likely to acquire one during treatment with antibiotics or in the month after, according to the CDC.
In 2021, there were nearly 119,000 CDIs among hospitalized patients, and roughly 20% to 25% of these people will experience a recurrent infection, according to the CDC.
“Hospital-acquired C. difficile has considerable impact on patients’ quality of life, as well as financial implications for health care systems,” Kari A. Mergenhagen, PharmD, BCPS, BCIDP, an infectious disease clinical pharmacy specialist for the Veterans Affairs of Western New York Healthcare System, told Healio.
“Tigecycline has been used for salvage therapy for C. difficile, so we hypothesized that doxycycline may share the same properties,” she said. “We were also seeing increased rates of C. difficile in general in hospitalized patients at our facility and were looking for methods to help decrease rates.”
Mergenhagen and colleagues conducted a retrospective analysis of more than 156,000 people hospitalized with pneumonia at a VA hospital between Jan. 1, 2009, and Aug. 25, 2022.
The researchers included only patients with CAP treated with IV ceftriaxone, and compared outcomes between those treated for CDI with either doxycycline or azithromycin. Patients diagnosed with Legionella pneumonia or viral pneumonia were excluded because different antibiotic regimens are required for treatment.
Of the 156,000 patients included in the analysis, 86.9% received azithromycin and 13.1% received doxycycline, with 0.6% and 1.1% in each group having a prior positive C. difficile PCR test in the previous year.
According to the study, just over 1,200 patients developed CDI within 30 days of starting antibiotics, but overall rates of CDI were low in both groups at 0.8% in the azithromycin group and 0.7% in the doxycycline group. Among patients with a history of CDI, 12.2% developed a new infection.
Overall, CDI risk decreased by 17% among patients receiving doxycycline compared with patients taking azithromycin, and CDI incidence among people with a prior history of CDI decreased by 45%. The researchers noted, however, that in the subset of patients with no history of CDI in the previous year, doxycycline did not result in a statistically significant risk for CDI.
Mergenhagen said Legionella can take time to rule out, depending on the tests available at each facility but that it is important to rule it out because, overall, tetracyclines such as doxycycline are not recommended for Legionella because of resistance.
“Doxycycline, when used for atypical coverage, should be considered in patients admitted for CAP who have a prior history of C. difficile when Legionella can be ruled out,” Mergenhagen said.
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