Clostridioides difficile and Vancomycin-Resistant Enterococci in COVID-19 Patients with Severe Pneumonia.

Broad-spectrum antibiotics administered to patients with severe COVID-19 pneumonia pose a risk of infection caused by Clostridioides difficile. This risk is reduced mainly by strict hygiene measures and early de-escalation of antibiotic therapy. Recently, oral vancomycin prophylaxis (OVP) has also been discussed. This retrospective study aimed to assess the prevalence of C. difficile in critical COVID-19 patients staying in an intensive care unit of a tertiary hospital department of anesthesiology, resuscitation, and intensive care from November 2020 to May 2021 and the rates of vancomycin-resistant enterococci (VRE) after the introduction of OVP and to compare the data with those from controls in the pre-pandemic period (November 2018 to May 2019). During the COVID-19 pandemic, there was a significant increase in toxigenic C. difficile rates to 12.4% of patients, as compared with 1.6% in controls. The peak rates were noted in February 2021 (25% of patients), immediately followed by initiation of OVP, changes to hygiene precautions, and more rapid de-escalation of antibiotic therapy. Subsequently, toxigenic C. difficile detection rates started to fall. There was a nonsignificant increase in VRE detected in non-gastrointestinal tract samples to 8.9% in the COVID-19 group, as compared to 5.3% in the control group. Molecular analysis confirmed mainly clonal spread of VRE.

Clonal Diversity of Klebsiella spp. and Escherichia spp. Strains Isolated from Patients with Ventilator-Associated Pneumonia.

Ventilator-associated pneumonia (VAP) is one of the most severe complications affecting mechanically ventilated patients. The condition is caused by microaspiration of potentially pathogenic bacteria from the upper respiratory tract into the lower respiratory tract or by bacterial pathogens from exogenous sources such as healthcare personnel, devices, aids, fluids and air. The aim of our prospective, observational study was to confirm the hypothesis that in the etiology of VAP, an important role is played by etiological agents from the upper airway bacterial microflora. At the same time, we studied the hypothesis that the vertical spread of bacterial pathogens is more frequent than their horizontal spread among patients. A total of 697 patients required mechanical ventilation for more than 48 h. The criteria for VAP were met by 47 patients. Clonality of bacterial isolates from 20 patients was determined by comparing their macrorestriction profiles obtained by pulsed-field gel electrophoresis (PFGE). Among these 20 patients, a total of 29 PFGE pulsotypes of Klebsiella spp. and Escherichia spp. strains were observed. The high variability of clones proves that there was no circulation of bacterial pathogens among hospitalized patients. Our finding confirms the development of VAP as a result of bacterial microaspiration and therefore the endogenous origin of VAP.

[Effect of previous antibiotic therapy on the epidemiology of ventilator-associated pneumonia].

OBJECTIVES: Ventilator-associated pneumonia (VAP) is the most common nosocomial infection in intensive care patients. The aim of the study was to evaluate the effect of previous antibiotic therapy on the incidence of VAP, mortality and spectrum of bacterial pathogens. MATERIAL AND METHODS: The retrospective, observational study comprised patients over 18 years of age meeting the clinical criteria of VAP. Controls were patients requiring mechanical ventilation for more than 48 hours with no signs of VAP. Each group was divided into two arms according to previous antibiotic therapy. Tracheal aspirates and oropharyngeal swabs were taken from all patients. Cultured isolates were identified using standard microbiological techniques. Antimicrobial susceptibility testing was performed according to the European Committee on Antimicrobial Susceptibility Testing guidelines. In both groups, 28-day mortality, 90-day mortality and multidrug-resistant (MDR) bacterial pathogen frequency were evaluated. RESULTS: The study included 49 patients (32 patients with previous antibiotic therapy, 17 antimicrobial-naive patients). The proportion of individuals with previous antibiotic therapy was significantly lower in VAP patients (34%) than among controls group (66%; p = 0.02). The VAP criteria were met by 23 patients (11 with previous antibiotic therapy, 12 without the therapy). The Enterobacteriaceae including extended-spectrum beta-lactamase-producing strains and Pseudomonas aeruginosa were the most common pathogens isolated. MDR pathogens were statistically significantly more frequent in patients with previous antibiotic therapy (77% vs. 33%; p = 0.047). In patients with previous antibiotic therapy, 28-day mortality was lower (18%; n = 2) than in antimicrobial-naïve patients (33%, n = 4; p = 0.640). The difference was more pronounced in 90-day mortality, albeit with low statistical significance (18%, n = 2 vs. 58%, n = 7; p = 0.089). CONCLUSIONS: Previous antibiotic therapy was associated with a lower incidence of VAP and a higher frequency of MDR bacterial pathogens. VAP antibiotic therapy modified according to knowledge of previous antibiotic therapy and cultured isolates was correlated with lower 28-day and 90-day mortality rates.