Comparative Study of Bacterial Culture Isolates and Drug Resistance Patterns Among Elderly Patients with Bacterial Community-Acquired Pneumonia Before and During the COVID-19 Pandemic

Background: The COVID-19 pandemic has changed the microbiological distribution and drug-resistance patterns of pathogens in community-acquired pneumonia (CAP). This study aimed to evaluate these among elderly patients with CAP before and during COVID-19. Methodology: Data was collected from patients aged 65 to 85 years with a diagnosis of bacterial pneumonia admitted to the Veterans Memorial Medical Center pre-COVID-19 and during COVID-19. The study compared bacterial pathogens, antimicrobial resistance patterns, length of hospital stay, and mortality between the two groups. Results: Data from 243 patients was analyzed. The COVID-19 group was younger and had more males compared to the pre-COVID-19 group (median age 70 [IQR 67–75] vs 74 [IQR 67–80] years; p = 0.015 and 74.50% vs 56.45%; p = 0.005, respectively). Hypertension was the most common comorbidity in the pre-COVID-19 group while diabetes was most common in the COVID-19 group. Similar proportions of almost all bacterial pathogens were observed. Among patients without COVID-19 co-infection, antimicrobial resistance was higher in the pre-COVID-19 group but was not significant (61.90% vs 55.56%; p = 0.316). Multidrug-resistant (MDR) pathogens were found to be higher in the COVID-19 group (21.37% vs 9.52%; p = 0.010). The majority of patients in both groups had prolonged hospital stays (~61%). Overall mortality was lower in the COVID-19 group (41.88% vs. 56.35%; p = 0.024) while, for patients with MDR, mortality was higher in the COVID-19 group (24.49% vs 8.45%, p = 0.016). Conclusion: The distribution of bacterial isolates did not differ significantly between pre-COVID-19 and COVID-19 periods. MDR was higher during the COVID-19 period. For MDR-infected patients, mortality was higher in the COVID-19 group. The findings of this study help inform the antimicrobial stewardship program of the institution. Vigilant surveillance and regular reporting of bacterial pathogens are needed to improve patient outcomes.