Isolation and Molecular Identification of Pathogenic Fungi from Cockroaches Caught from Babol Teaching Hospitals during 2021-2022

Background and Aim: Cockroaches are potential carriers of a wide range of pathogenic microorganisms (fungi, bacteria and parasites). Considering the importance of these insects in the transmission of pathogenic fungi and their impact on the health of hospitalized people, the aim of this study was isolation and molecular identification of pathogenic fungi from the external and internal surfaces of cockroaches collected from three educational hospitals of Babol city, Mazandaran Province, Iran. Materials and Methods: Cockroaches were caught by a sterile manual method and after washing to remove surface contamination with 70% ethyl alcohol for 2min, 100 µL of the solutions from the external and internal parts of cockroaches were cultured on Sabouraud’s dextrose agar with 0.05% chloramphenicol and incubated at 30 °C for 3 weeks. The different yeast and filamentous colonies were distinguished using standard mycological methods. The PCR-RFLP method and the restriction enzymes Msp I and Bln I were used for the differentiation of Candida species, and the restriction enzyme Alw I for Aspergillus species. Results: A total of 85 fungi species/genera were isolated from all 50 studied cockroaches, including German cockroaches 15 (30%), American cockroach 20 (40%) and brown 15 (30%), which included 52 isolates from external surfaces (61%) and 33 isolates from internal surfaces of cockroaches (39%). Of the total number of 49 filamentous fungi, Aspergillus fumigatus 16 (32.65%) and out of the total number of 36 yeasts identified, Candida albicans 14 (38.89%) were the most common fungi isolated in this study. Other filamentous fungi and yeasts isolated from cockroaches include Aspergillus niger 11 (22.45%), Aspergillus flavus 8 (16.32%), Penicillium 4 (8.2%), Rhizopus 3 (6.1%), Cladosporium 3 (6.1%), Mucor 2 (4%), Alternaria 2 (4%), Candida parapsilosis 6 (16.67%), Candida krusei 12 (33.33%), Candida glabrata 3 (8.33%), and Candida tropicalis 1 (2.78%) were isolated. Conclusion: Considering the isolation of several fungal species from cockroaches and their importance in the possible mechanical transmission of common fungal infections in hospitals, these insects can be a source of continuous transmission of infection, if there is no regular preventive disinfection of the hospital environment.