Investigating Antibiotic Resistance Genes in Marketed Ready‐to‐Eat Small Crickets (Acheta domesticus)

Abstract

The present investigation was aimed at evaluating the occurrence of transferable genes conferring resistance to tetracyclines, macrolide‐lincosamide‐streptogramin B (MLSB), vancomycin, beta‐lactams, and aminoglycosides in 32 samples from eight batches of ready‐to‐eat crickets (Acheta domesticus) commercialized by four European Union producers (two batches per producer). Bacterial DNA extracted directly from the insects was subjected to optimized polymerase chain reaction (PCR) and nested‐PCR assays for the qualitative detection of 12 selected antibiotic resistance (AR) genes. Microbial enumeration demonstrated high counts of spore‐forming bacteria and total mesophilic aerobes. Statistical analyses revealed significant differences between different producers and insect batches. Regarding AR genes, a high prevalence of genes conferring resistance to tetracycline [tet(M), tet(O), tet(K), tet(S)] was observed, together with the presence of genes conferring resistance to erythromycin [erm(B), erm(C)], beta‐lactams (blaZ and mecA), and aminoglycosides [aac(6’)‐Ie aph(2”)‐Ia]. We performed a principal component analysis based on the AR gene frequencies that differentiated samples of batch 1 from those of batch 2. This analysis provided evidence for a difference between the producer from France and all the other producers among the batch 1 samples. Practical application Overall, an intrabatch variation was seen in the transferable resistances among different producers. This evidence, coupled with the observed differences in the viable counts, suggests a low standardization of the production processes. Hence, a prudent use of antimicrobials during the rearing of insects destined for human consumption is strongly recommended, as well as a need for a full standardization of production technologies.

Chemical Composition, Nutrient Quality and Acceptability of Edible Insects Are Affected by Species, Developmental Stage, Gender, Diet, and Processing Method

“…In food industries in Europe, a recent study has revealed antibiotic resistant genes in A. domesticus. As a preventive measure, Roncolini et al [ 163 ] suggested standardization of the production processes and a prudent use of antimicrobials during the rearing of edible insects. Even though Spiroplasma sp.…”

Occurrence of Antibiotic Resistance Genes in Hermetia illucens Larvae Fed Coffee Silverskin Enriched with Schizochytrium limacinum or Isochrysis galbana Microalgae

“…The samples that were negative for each of the AR genes under study were further subjected to nested PCR assays designed to enhance the gene detection sensitivity, as previously reported by Garofalo et al [31]. The high sensitivity of the latter method was confirmed in recent studies aimed at detecting the same AR genes in different edible insects [14,16,17,19,20] as well as in human stool and saliva samples [30,33].…”

“…The primers used for the PCR and nested PCR as well as the thermal cycling conditions for all but the aac-aph gene were as previously reported by Milanović et al [30], while the PCR conditions for the latter gene were detailed by Garofalo et al [31]. DNA was extracted from 12 bacterial reference strains [16,17,19,20], each carrying one of the AR genes under study, and they were used as positive controls in each PCR and nested PCR assay, whereas the DNA extracted from Enterococcus faecalis JH2-2 [32] was used as a negative control. Furthermore, a blank control containing molecular biology grade water instead of DNA was used in each assay to exclude the presence of PCR contaminants.…”

“…Previous studies were mainly focused on the presence of AR genes in small cricket powder, locusts, black ants, giant water bugs, rhino beetles, termite alates, silkworm pupae, mole crickets and black scorpions [14]; grasshoppers [15,16]; mealworms [14,15,17,18]; and small crickets [14,18,19], all reporting a high prevalence of genes conferring resistance to tetracyclines and erythromycin. The possible contribution of feed to the occurrence of AR genes in edible insects as well as their vertical transmission via insect egg smearing has already been reported by Osimani et al [20].…”

The honeybee gut resistome and its role in antibiotic resistance dissemination

“…For example, an investigation aiming at evaluating the occurrence of ARGs in crickets provided evidence that deliberately used or naturally occurring antibiotics were selective pressure on the microbiota of insects (Roncolini et al. 2019). ARBs were also isolated from ants, flies, spiders, cockroaches, and moths (Hassan et al.…”