Periplaneta americana (Blattodea: Blattidae) fungal pathogens in hospital sewer systems: molecular and phylogenetic approaches.

Cockroaches are known as mechanical vectors of some pathogens that can infect humans. The present study aims to rapidly identify Periplaneta americana fungal pathogens from sewer systems of public hospitals in Esfahan using the polymerase chain reaction (PCR) technique. A total of 55 P. americana cockroaches were randomly collected by direct trapping from sewer systems of seven hospitals and screened for fungal infectious agents using standard morphological methods and the PCR sequencing. From the American cockroach, we isolated 62 yeasts and 31 molds from the surface, hemocoel, and digestive tract of P. americana. Based on DNA sequence comparisons and other taxonomic characteristics, they were identified as more than four species of yeast and four species of mold. Yeast species including Pichia kudriavzevii, Candida glabrata, Pichia kluyveri, and Candida viswanathii, and molds such as Aspergillus niger, Penicillium italicum, Mucor plumbeus, and Rhizopus oryzae were isolated repeatedly from the surface, hemocoel, and digestive tract of P. americana. Our results show that the use of a combination of morphological, molecular techniques, and phylogenetic analysis can lead to the identification of pathogenic fungal agents in American cockroaches and also knowledge of fungal pathogens-arthropod host relationships.