Descriptive Report of Microorganisms Detected in Cultures of COVID-19 Patients Developing Secondary Infection After Tocilizumab Use

Tocilizumab an anti-inflammatory medication previously approved for the treatment of rheumatoid arthritis, was widely used during the COVID-19 pandemic. Secondary infections following the use of tocilizumab were expected knowing its inhibitory effect on the cascade of inflammation by blocking IL6. Patterns of microorganism growth in positive culture reports after tocilizumab use have not been widely assessed in the literature. In this retrospective study, we included all patients diagnosed with severe COVID-19 admitted to the intensive care unit (ICU). Patients were divided into two groups; tocilizumab receivers and non-receivers. Patient records were evaluated for the presence of positive culture results. Patterns of microorganism growth and their sensitivity to antibiotics were assessed and compared between the two groups. Seventy-seven patients (74.8%) in the tocilizumab group developed secondary infection, irrespective of the culture origin. The rate of positive culture result was significantly higher in the group treated with tocilizumab (P-value 0.022). Candida and Acinetobacter species were the most common microorganisms detected in sputum cultures, Candida and Escherichia coli (E. coli) species were dominant in urine cultures, and methicillin-resistant Staphylococcus Aureus (MRSA), Acinetobacter and Candida species were the leading microorganisms of positive blood cultures. No significant difference was observed in the culture growth patterns in both groups. The presence of multi-drug resistant nosocomial microorganisms in ICU-admitted COVID-19 patients may be associated with causes other than tocilizumab use and may lead to poor patient outcomes.