Ventilator-Associated Pneumonia in Critically Ill Patients With COVID-19

Mailis Maes; Ellen Higginson; Joana Pereira-Dias; Martin D. Curran; Surendra Parmar; Fahad Khokhar; Delphine Cuchet-Lourenco; Janine Lux; Sapna Sharma-Hajela; Benjamin Ravenhill; Islam Hamed; Laura Heales; Razeen Mahroof; Amelia Solderholm; Sally Forrest; Sushmita Sridhar; Nicholas M. Brown; Stephen Baker; Vilas Navapurkar; Gordon Dougan; Josfin Bartholdson Scott; Andrew Conway Morris


Crit Care. 2021;25(25) 

In This Article


Pandemic COVID-19 is associated with a high number of patients suffering from severe acute respiratory syndrome (SARS). Such patients can spend significant periods of time in intensive care units (ICU), with up to 80% of patients admitted to ICU requiring invasive mechanical ventilation.[1,2] Critically ill patients are at high risk of nosocomial pneumonia, especially when ventilated.[3] The reasons for this includes breach of natural defences by invasive devices,[4] sedation and impairment of coughing and mucociliary clearance, and the immunoparetic effects of critical illness.[5,6] Early reports indicated that critically ill patients infected with SARS-CoV-2 had a high prevalence of nosocomial pneumonia, especially ventilator-associated pneumonia (VAP).[7] More recent reports, including a large survey from a single hospital[8] and a synthesis of the literature[9] suggested that rates of secondary infections were low, although neither study focussed specifically on critical care. There remains considerable uncertainty around the incidence of nosocomial infections in severe COVID-19, which has led to recent calls for more analysis on the frequency, timing, and causative organisms of these important adverse events.[10]

Reports of ICU-acquired infection in patients with COVID-19 have been limited and have often not reported the details of the causative organisms,[7] or have focused on the incidence of one particular infection such as invasive aspergillosis.[11] Importantly, we are not aware of reports of ICU-acquired infections comparing patients with COVID-19 and those without managed contemporaneously within the same settings, which is key to interpreting the frequency, timing, and causative organisms leading to these infections.

Ventilator-associated pneumonia (VAP), the commonest ICU-acquired infection,[3] can be challenging to diagnose as a range of non-infectious diseases may mimic the clinical picture of radiographic infiltrates, systemic inflammation and impaired oxygenation that typifies VAP.[12] To limit overdiagnosis and facilitate appropriate antimicrobial therapy in VAP, guidelines advocate the use of culture- based approaches.[13,14] However, molecular tests to detect multiple pathogens (viruses and bacteria) are becoming more accessible and may further reduce unnecessary antimicrobial therapy[15] whilst enhancing the detection of hard to culture organisms.

During our hospital's first wave of COVID-19 admissions we noted an apparent increase in the rate of VAP. In this study, we therefore aimed to identify and compare the distribution of VAP in critically ill ventilated COVID-19 patients compared to ventilated non-SARS-CoV-2 infected patients admitted to the same unit. We performed conventional microbiological culture on all lower respiratory tract samples. Bronchoalveolar lavage (BAL) was also analysed using a multi-pathogen TaqMan array card (TAC) we have developed and reported previously.[16] In a sub-set of BALs we assessed the composition of the bacterial lung microbiome in bronchoalveolar lavage (BAL) by 16S sequencing.