Introduction: Secondary Bacterial Infections (SBIs) of the respiratory system are one of the biggest medical concerns in patients undergoing hospitalization with a diagnosis of COVID-19. This study aims to provide relevant data for the initiation of appropriate empirical treatment after examining the etiology and antimicrobial resistance of SBIs in COVID-19 patients under care in the Intensive Care Units (ICUs) in the largest pandemic hospital of our country. Methodology: Between March 16, 2020 and December 31, 2021, 56,993 COVID patients were hospitalized, of which 7684 were admitted to ICUs. A total of 1513 patients diagnosed with SBIs have been included in this study. During the course of the study, demographic data, clinical course, etiology and antimicrobial resistance data of all patients were collected. Results: The most common causative agents of SBIs were inferred as Acinetobacter baumanii (35.1%), Staphylococcus aureus (15.2%), Klebsiella pneumoniae (12.3%) and Pseudomonas aeruginosa (10.4%). The isolation rates of carbapenem-resistant and colistin-resistant A. baumannii, K. pneumoniae and P. aeruginosa were 83.7%; 42.7%, 79.2%, and 5.6%, 42.7%, 1.7%, respectively. Acinetobacter pittii clustering was seen in one of the ICUs in the hospital. Multidrug resistant 92 (5.4%) Corynebacterium striatum isolates were also found as a causative agent with increasing frequency during the study period. Conclusions: SBI of the respiratory system is one of the major complications in patients hospitalized with COVID-19. The antimicrobial resistance rates of the isolated bacteria are generally high, which indicates that more accurate use of antibacterial agents is necessary for SBIs in patients hospitalized with COVID-19 diagnosis.

Rhodococcus equi is a microorganism that was first described in horses and later it had been found out to cause opportunistic infections in immunosuppressed patients. It causes especially pulmonary infections in immunocompromised patients while it rarely causes diseases such as septic arthritis and soft tissue infections. It is important to question epidemiological risk factors for the diagnosis of the disease. Also the clinician-microbiologist relationship is important in the laboratory diagnosis of the microorganism because it is possible to be missed as the part of normal flora or contaminant or to be confused with microorganisms with similar phenotypic features (Nocardia species or rapidly growing mycobacteria). Rarely, it has been reported in immunocompetent patients, as in our case. MEDLINE, SCOPUS, Google Scholar, and Cochrane searches were performed using keywords Rhodococcus equi and Corynebacterium equi from 1945 to July 2021. A total of 582 articles were determined. Articles containing these keywords were then scanned for words "humans", “soft tissue infections”, and “cellulite” and a total of 42 articles were listed in the end. A total of 14 case reports of soft tissue infection/cellulitis in immunocompetent patients related R. equi were detected in the literature In our case, there was a soft tissue infection and R. equi was detected in the abscess culture. Obtaining culture and determining the factor is very important in the treatment of infections. In this report, soft tissue infections caused by R. equi in immunocompetent patients are reviewed.