Objective and background: In Japan, an increase in the elderly population is associated with an increased incidence of aspiration pneumonia. Treatment guidelines for aspiration pneumonia recommend the use of antibiotics effective against anaerobic bacteria, such as carbapenems. However, the role of anaerobic bacteria in aspiration pneumonia and the clinical efficacy of meropenem in elderly aspiration pneumonia patients have only begun to be investigated.
Methods: A prospective study of 62 elderly hospitalized patients with aspiration pneumonia (34 males, 28 females; mean age 86.6 years) was conducted. The causative organisms of aspiration pneumonia, including anaerobic bacteria, were investigated using fiberoptic bronchoscopy. In addition, the efficacy and safety of intravenous meropenem for this treatment of this condition were evaluated.
Results: When disease severity was classified according to the Japanese Respiratory Society (JRS) guidelines, 80.7% of the cases in this study were graded as "most severe". The overall detection rate of bacteria was 87.1% (monomicrobial, 32.3%; polymicrobial, 54.8%). Of the 111 pathogens detected (14 anaerobic pathogens remained unidentified), anaerobic bacteria accounted for 19.8% and gram-negative enteric bacilli made up 19.8%. The overall clinical efficacy rate of meropenem therapy (1.0 g/day) was 61.3%. The mortality rate was 9.7%, and anaerobic bacteria coexisted with aerobic bacteria in 66.7% of the patients who died.
Conclusion: The use of antibiotics effective against anaerobic bacteria may be necessary for patients with potentially fatal aspiration pneumonia. Meropenem therapy for aspiration pneumonia is clinically effective and tolerable in elderly patients.