Flora Infeksiyon Hastalıkları ve Klinik Mikrobiyoloji Dergisi (Dec 2020)
Clinical Features of Cases with Anaerobic Infection, Distribution of Anaerobic Bacteria and Fatality in Anaerobic Bacteremia
Abstract
Introduction: This study aimed to determine the distribution of anaerobic bacteria species, which are the causative agents of infection, in order to investigate the epidemiological and clinical characteristics of the cases and evaluate fatality in cases with an aerobic bacteremia. Materials and Methods: One hundred and twenty-five cases who were determined with 148 isolates of anaerobic bacteria were included into this study at Ankara Numune Training and Research Hospital Medical Microbiology Laboratory between January 2014-February 2018. The specimens requested to undergo anaerobic evaluation and transported to the laboratory under anaerobic suitable conditions were prepared with Gram staining and inoculated in the Schaedler agar. After appropriate incubation, the identification of isolated anaerobic bacteria at the level of species was performed by using matrix-assisted laser desorption time-of-flight (MALDI-TOF MS). Results: Of the 125 cases who had an anaerobic infection, 60% were males, and mean age was 52.69 ± 18.5 years. Intra-abdominal and skin and soft tissue infections were the most common source of infection. One hundred and twenty-eight clinical specimens (78 abscesses, 50 blood cultures) which were sent from cases were identified with 148 anaerobic bacteria species. We detected the most common isolated species as Bacteriodes spp., Actinomyces spp. and Clostridium spp., respectively. The most common anaerobic bacteria species isolated from blood cultures of 50 cases with anaerobic bacteremia were Bacteroides spp., Clostridium spp., and intra-abdominal infection was the most common source for anaerobic bacteremia. Fusobacterium nucleatum (5/6; 83.3%) was the most frequent species in Fusobacterium bacteremia. F. nucleatum bacteremia was detected in an older population and was often associated with underlying malignancy. F. necrophorum bacteremia occurred in a younger population without underlying comorbidities and was diagnosed as Lemierre’s syndrome. Fatality rate was 51% in anaerobic bacteremia. Fatality was significantly higher in patients who were followed up in the intensive care unit and had high Charlson index (p< 0.05). Conclusion: MALDI-TOF MS has become an important method for the identification of anaerobic bacteria with its reliable results in a very short time. The most common anaerobic microorganism was Bacteroides spp., and the two most frequent sources of infection were intraabdominal and skin and soft tissue infections. We observed that most of the cases with F. nucleatum bacteremia had malignancy and an older population. The case with F. necrophorum bacteremia was young and had no underlying comorbidities. In this study, fatality rate (51%) was detected high in anaerobic bacteremia. Therefore, the routine use of anaerobic blood culture bottles is important for the identification and for the effective treatment of cases with anaerobic bacteremia.
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