Antagonistic Activity of Bacteria Isolated from the Periplaneta americana L. Gut against Some Multidrug-Resistant Human Pathogens

Abstract

The insect gut is home to a wide range of microorganisms, including several bacterial species. Such bacterial symbionts provide various benefits to their insect hosts. One of such services is providing metabolites that resist infections. Little data are available about gut-inhabiting bacteria for several insect groups. Through the present work, the gut bacteria associated with the American cockroach (Periplaneta americana L.) were isolated, identified, and studied for their potential antimicrobial activity against multidrug-resistant (MDR) human pathogens. The cockroaches were collected from three different environmental sites. Gut bacteria were isolated, and sixteen species of bacteria were identified using Vitek MALDI-TOF MS. The antagonistic activity of the identified bacteria was tested against a panel of multidrug-resistant bacteria and fungi, namely: methicillin-resistant Staphylococcus aureus (MRSA) (clinical isolate), Streptococcus mutans Clarke (RCMB 017(1) ATCC ® 25175™) (Gram-positive bacteria), Enterobacter cloacae (RCMB 001(1) ATCC® 23355™) and Salmonella enterica (ATCC® 25566™) (Gram-negative bacteria). The isolates were also tested against human pathogenic fungi such as Candida albicans (RCMB005003(1) ATCC® 10231™), Aspergillus niger (RCMB002005), Aspergillus fumigatus (RCMB002008), Aspergillus flavus (RCMB002002), and Penicillium italicum (RCMB 001018(1) IMI193019). The results indicated that some bacterial species from the cockroach gut could antagonize the growth activity of all the tested pathogens. Such antimicrobial properties could ultimately lead to the future development of therapeutic drugs. The evaluation and mode of action of antagonistic gut bacteria against the most affected MDR pathogens were demonstrated using transmission electron microscopy (TEM).

Evaluation of antimicrobial activity of bacterial symbionts isolated from wild field cockroach Blattella vaga from Saudi Arabia

“…As environmental heterogeneity of insect habitats helps in increasing the antagonistic effect of its bacterial symbionts toward pathogens ( Iqbal et al, 2014 ). The data that also supported through the studying of associated bacteria of the American cockroach gut ( Amer et al, 2021 ). The isolated Bacillus subtilis show no antipathogenic activity to all microbes tested, although this species of bacteria was known before the antibiotic era as an immunostimulatory aid for the treatment of gastrointestinal and urinary tract diseases ( Ciprandi et al, 1986 ).…”

“…There were clear differences in such bacterial symbionts between the studied cockroaches in the two different collection sites. Recently, a study that evaluates the antagonistic activity of gut bacteria of American cockroach Periplaneta americana L. shows similar results, as the habitat of American cockroach individuals affects greatly the associated bacterial species of cockroach gut ( Amer et al, 2021 ). Also, the same results appear during the study of symbionts of other insects like the associated bacteria of house fly ( Rady et al, 2007 ).…”

“…Several natural and artificial sources were tested to accomplish such poupous ( Rajanbabu and Chen, 2011 , Sargiya et al, 2017 ). Insects and their associated microflora form a very good store to the new era of antimicrobial and antipathogenic medications ( Amer et al, 2021 , Al-Ghamdi et al, 2021 , Masry et al, 2021 ).…”

“…Bacillus licheniformis is also a common inhabitor of bird plumage especially on ground-dwelling birds (like sparrows) and aquatic species (like ducks) ( Whitaker et al, 2005 ) while Bacillus subtilis is known from the gut of several animal species including insects such as honey bees ( Sudhagar et al, 2017 ). So, the occurrence of these species on the gut of Blattella vaga through the two collection sites consider a normal thing, especially that these species collected from other cockroach gut before ( Amer et al, 2021 ).…”

“…Several previous studies have discussed cockroaches as sources for several alternative drugs ( Whitten and Ratcliffe, 1999 , Basseri et al, 2019 , Kim et al, 2020 ). Also, some works illustrate the antimicrobial activity of some species of gut-associated bacteria of cockroaches against multidrug-resistant pathogenic human microbes ( Akbar et al, 2018 , Amer et al, 2021 ), but this is the first time to point out the antipathogenic activity of gut symbionts of Blattella vaga. The result looks very promising especially for developing antifungal agents from Bacillus licheniformis against Candida albicans .…”