Risk factors for antibiotic resistance in hospital-acquired and ventilator-associated pneumonia

Understanding risk factors for antibiotic resistance (AR) in patients with hospital-acquired pneumonia (HAP) and ventilator-associated pneumonia (VAP) is important to select appropriate initial antibiotics and reduce broad-spectrum antibiotic overuse. However, available evidence is limited. We aimed to identify risk factors for AR in those patients.

This prospective observational study was conducted at a tertiary-care hospital. Pathogens with AR were defined as those resistant to ampicillin-sulbactam or ceftriaxone. Risk factors for AR in patients with HAP and VAP were assessed using penalized logistic regression analysis.

In total, 557 patients with HAP and VAP were enrolled. Pathogens were isolated from 315 patients, with AR identified in 68.3% (215/315). Among antibiotic-resistant pathogens (ARPs), Pseudomonas aeruginosa was isolated most frequently, followed by methicillin-resistant Staphylococcus aureus (MRSA). Significant risk factors for AR were chronic renal diseases (adjusted odds ratio: 2.82, 95% confidence interval: 1.79-7.83), history of ARP infection/colonization within the past 1 year (2.80, 1.90-7.02), bedridden state (1.84, 1.28-3.91), tube feeding (1.58, 1.09-2.98), and peripheral or central venous catheterization (1.57, 1.06-2.96). Additionally, a risk factor for ARPs that should be treated with anti-MRSA antibiotics was prior MRSA infection/colonization history. Those for ARPs requiring dual antipseudomonal antibiotics included prior non-MRSA ARP or MRSA infection/colonization history and bedridden state.

The five factors we highlighted can be important criteria for identifying patients at risk of AR. Physicians should consider these potential risk factors when selecting antibiotics for initial empirical therapy in patients with HAP and VAP.