Epidemiology, Treatment, and Prevention of Nosocomial Bacterial Pneumonia

Abstract

Septicaemia likely results in high case-fatality rates in the present multidrug-resistant (MDR) era. Amongst them are hospital-acquired pneumonia (HAP) and ventilator-associated pneumonia (VAP), two frequent fatal septicaemic entities amongst hospitalised patients. We reviewed the PubMed database to identify the common organisms implicated in HAP/VAP, to explore the respective risk factors, and to find the appropriate antibiotic choice. Apart from methicillin-resistant Staphylococcus aureus and Pseudomonas aeruginosa, extended-spectrum β-lactamase-producing Enterobacteriaceae spp., MDR or extensively drug-resistant (XDR)-Acinetobacter baumannii complex spp., followed by Stenotrophomonas maltophilia, Chryseobacterium indologenes, and Elizabethkingia meningoseptica are ranked as the top Gram-negative bacteria (GNB) implicated in HAP/VAP. Carbapenem-resistant Enterobacteriaceae notably emerged as an important concern in HAP/VAP. The above-mentioned pathogens have respective risk factors involved in their acquisition. In the present XDR era, tigecycline, colistin, and ceftazidime-avibactam are antibiotics effective against the Klebsiella pneumoniae carbapenemase and oxacillinase producers amongst the Enterobacteriaceae isolates implicated in HAP/VAP. Antibiotic combination regimens are recommended in the treatment of MDR/XDR-P. aeruginosa or A. baumannii complex isolates. Some special patient populations need prolonged courses (>7-day) and/or a combination regimen of antibiotic therapy. Implementation of an antibiotic stewardship policy and the measures recommended by the United States (US) Institute for Healthcare were shown to decrease the incidence rates of HAP/VAP substantially.

Keywords: Acinetobacter baumannii complex species; Pseudomonas aeruginosa; antibiotic combination; carbapenemase; ceftazidime-avibactam; extended-spectrum β-lactamase-producing Enterobacteriaceae species; extensively drug-resistant; hospital-acquired pneumonia; methicillin-resistant Staphylococcus aureus; ventilator-associated pneumonia.

Figure 1

Strategies of antibiotic therapy for hospital-acquired pneumonia or ventilator-associated pneumonia. HAP, hospital-acquired pneumonia. VAP, ventilator-associated pneumonia. MDR, multidrug-resistant. APACHE, Acute Physiologic and Chronic Health Evaluation. ICU, intensive care unit. MRSA, methicillin-resistant Staphylococcus aureus. CRE, carbapenem-resistant Enterobacteriaceae.