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Front. Microbiol. | doi: 10.3389/fmicb.2018.03036

Investigation of the dominant microbiota in ready-to-eat grasshoppers and mealworms and quantification of carbapenem resistance genes by qPCR

  • 1Università Politecnica delle Marche, Italy

In this study, thirty samples of processed edible mealworms (Tenebrio molitor L.) and thirty samples of grasshoppers (Locusta migratoria migratorioides) were obtained from producers located in Europe (Belgium and the Netherlands) and Asia (Thailand) and subjected to PCR-DGGE analyses.
The PCR-DGGE analyses showed that species in the genus Staphylococcus were predominant in the samples of mealworms from Belgium and grasshoppers from the Netherlands; species in the genus Bacillus were detected in the samples of mealworms and grasshoppers from Thailand. Moreover, Weissella cibaria/confusa/sp. was found in grasshoppers from Belgium.
Since, data concerning the role of novel foods such as edible insects in the dissemination of carbapenem resistance are currently lacking, the quantification of five carbapenemase encoding genes (blaNDM-1, blaVIM-1, blaGES-1, blaOXA-48, and blaKPC) using qPCR method was also carried out in all the samples under study.
The genes coding for GES-1 and KPC were not detected in the analyzed samples. A very low frequency of blaOXA-48 (3%) and blaNDM-1 (10%) genes was detected among the mealworm samples. In contrast, grasshoppers were characterized by a high incidence of the genes for OXA-48 and NDM-1, accounting for 57% and 27% of the overall grasshopper samples, respectively. The blaVIM-1 gene was detected exclusively in two grasshopper samples from Thailand, showing only 7% positivity. The analysis of variance showed that all the effects (producers, species, and producers x species) were statistically significant for blaNDM-1, whereas for blaOXA-48 and blaVIM-1, no significant effects were detected for the same source of variation.
Further studies are necessary to assess the possible role of edible insects as reservoirs for the resistance to carbapenems and to understand the correlation with the insect microbiota. Furthermore, an intensified surveillance plan examining the occurrence of carbapenemase encoding genes in the food chain and in environmental compartments is needed for a proper risk assessment. In such a context, the appropriate use of antimicrobials represents the main preventive action that should always be applied.

Keywords: Edible insects, antibiotic resistance, PCR-DGGE, Carbapenemase genes, qPCR

Received: 10 Sep 2018; Accepted: 26 Nov 2018.

Edited by:

Patrícia Poeta, University of Trás-os-Montes and Alto Douro, Portugal

Reviewed by:

Ziad Daoud, University of Balamand, Lebanon
Victor Ladero, Spanish National Research Council (CSIC), Spain  

Copyright: © 2018 Milanović, Osimani, Roncolini, Garofalo, Aquilanti, Pasquini, Tavoletti, Vignaroli, Canonico, Ciani and Clementi. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: Dr. Cristiana Garofalo, Università Politecnica delle Marche, Ancona, 60121, Marche, Italy, c.garofalo@univpm.it