Severe community‐acquired pneumonia compared to severe community‐acquired Acinetobacter baumannii pneumonia in Reunion Island: A retrospective study

Abstract

Acinetobacter baumannii (Ab) has emerged in the last decades as a cause of community‐acquired pneumonia (CAP) in tropical and subtropical regions. We previously conducted the first investigation on this topic in France with a case series of severe CAP‐Ab in Reunion Island over an eight‐year period. In the present work, we aim to highlight the specific aspects of CAP‐Ab by comparing our case series with an historical cohort (PAC_RUN), obtained by retrospective chart review (2016–2021) of severe community‐acquired pneumonia cases on Reunion Island, in which CAP‐Ab was ruled out. During the study period, eight CAP‐Ab cases were identified, giving an incidence of 0.1 cases per 100,000 people/year, and an incidence of 16.5 cases per 100,000 people/year for non‐Ab‐related CAP (n = 761). By comparing with non‐Ab‐related CAP, patients had more excessive alcohol use (75% vs. 25.6%, p = 0.005) and lower body mass index (21 vs. 24 kg/m2, p = 0.004). Six cases (75%) of CAP‐Ab occurred during the rainy season (p = 0.06). Mortality was higher (62.5% vs. 24.3%, p = 0.02) and time to death was shorter (median 2 days vs. 7, p = 0.009) in the CAP‐Ab group. Bacteraemic pneumonia was strongly associated with CAP‐Ab (62.5% vs. 15.7%, p = 0.004). Significant differences were found in the need for renal replacement therapy (75% vs. 17.2%, p < 0.001), catecholamine use (100% vs. 54.5%, p = 0.01) and use of invasive mechanical ventilation (100% vs. 62.7%, p = 0.03). Also, in the proportion of severe acute respiratory distress syndrome (62.5% vs. 23.2%, p = 0.02), septic shock (100% vs. 40.6%, p < 0.001), and cardiogenic shock (87.5% vs. 15.9%, p < 0.001). Compared to severe non‐Ab‐related CAP, severe CAP‐Ab is characterised by higher mortality, associated with a high frequency of multiple organ failure. Excessive alcohol consumption and malnutrition seem to be risk factors. To improve outcomes, broader spectrum antibiotic therapy must be immediately proposed when CAP‐Ab is suspected.