Inside the ICU: COVID-19's Impact on Ventilator-Associated Pneumonia

As the dust begins to settle from the COVID-19 pandemic, one persistent challenge within the ICU remains prominent: ventilator-associated pneumonia (VAP). A recent retrospective study out of Romania’s Mures County Clinical Hospital underscores a troubling intersection between mechanical ventilation, multidrug-resistant (MDR) bacteria, and the clinical realities faced during COVID-19. The two-year investigation, published in Antibiotics, highlights the substantial burden of VAP among ICU patients, along with the concerning levels of resistance to carbapenems and other frontline antibiotics.

The study analyzed 122 ICU patients between April 2021 and April 2023 who were mechanically ventilated for over 48 hours and developed VAP. Nearly half of these patients were SARS-CoV-2 positive at the time of admission. Patients with COVID-19 required longer ventilation and experienced higher mortality rates compared to non-COVID counterparts. However, the extended time on mechanical ventilation was itself a critical risk factor, correlating strongly with infection by MDR pathogens.

Microbial cultures revealed a familiar trio of culprits: Acinetobacter spp., Pseudomonas spp., and Klebsiella spp. Acinetobacter baumannii was both frequently identified and highly resistant. More than 50% of the Acinetobacter isolates displayed carbapenem resistance—an antibiotic class typically reserved for severe or refractory infections. Resistance among Klebsiella and Pseudomonas species was also notable, ranging between 22% and 26%.

Interestingly, MDR Acinetobacter baumannii was more frequently observed in non-COVID-19 patients, possibly reflecting greater prior healthcare exposure in this group. In COVID-19 patients, however, the Clinical Pulmonary Infection Score (CPIS) emerged as a particularly strong indicator of MDR infection. A CPIS above 5 was associated with perfect sensitivity and nearly 80% specificity in identifying these resistant infections.

The study also emphasized the role of ICU exposure duration. Patients who remained ventilated beyond 196 hours (just over 8 days) or who stayed in the ICU longer than 11.5 days were significantly more likely to develop MDR infections. These thresholds demonstrated valuable predictive capacity, according to ROC curve analysis.

In response to the high prevalence of MDR bacteria, nearly 87% of patients received combination antibiotic therapy. Common regimens included carbapenems, third-generation cephalosporins, fluoroquinolones, and polymyxins. Despite these aggressive treatment approaches, antimicrobial resistance posed significant challenges to effective management.

Laboratory trends added another layer of clinical insight. Higher neutrophil-to-lymphocyte ratios, along with reduced monocyte and eosinophil counts at 72 hours, were associated with poorer outcomes—particularly in COVID-19 patients. Radiologic deterioration, observed via chest X-rays and CT scans, further correlated with elevated mortality risk.

The mortality rate was notably higher in patients receiving invasive mechanical ventilation, especially among those with COVID-19. Prolonged ventilation, leukocytosis at 48 and 72 hours, increased neutrophil counts, and progressive pulmonary imaging changes all contributed to reduced survival odds. These findings reinforce the importance of early diagnosis and tailored antimicrobial strategies.

While the study was limited by its single-center scope and reliance on bronchial aspirates rather than bronchoalveolar lavage, its conclusions are relevant across a wide range of ICU settings. The rise of MDR pathogens in ventilated patients—exacerbated by the COVID-19 pandemic—warrants renewed focus on diagnostic precision, antimicrobial stewardship, and infection control protocols.

In today’s critical care landscape, managing MDR infections effectively requires more than appropriate antibiotic selection. It demands early risk identification, robust surveillance, and system-level strategies to reduce infection risks. As healthcare systems prepare for future infectious disease challenges, this study emphasizes that antimicrobial resistance remains an ongoing and growing concern in intensive care medicine.

Source

Stoian, Mircea, Adina Andone, Sergiu Rareș Bândilă, Danusia Onișor, Sergiu Ștefan Laszlo, Gabriela Lupu, Alina Danielescu, Dragoș-Florin Baba, Anca Meda Văsieșiu, Andrei Manea, and et al. 2025. "Mechanical Ventilator-Associated Pneumonia in the COVID-19 Pandemic Era: A Critical Challenge in the Intensive Care Units" Antibiotics 14, no. 1: 28. https://doi.org/10.3390/antibiotics14010028