Antimicrobial resistance and genetic relationships of enterococci from siblings and non-siblings Heliconius erato phyllis caterpillars

• Published in: PeerJ (San Francisco, CA) CA), 2020-02, Vol.8, p.e8647, Article e8647
• Main Authors: Huff, Rosana, Inhoque Pereira, Rebeca, Pissetti, Caroline, Mellender de Araújo, Aldo, Alves d'Azevedo, Pedro, Frazzon, Jeverson, GuedesFrazzon, Ana Paula
• Format: Article
• Language: English
• Subjects: Adults; Analysis; Antibacterial agents; Antibiotics; Antimicrobial agents; Antimicrobial profile; Antimicrobial resistance; Bacteria; Bacterial genetics; Biodiversity; Butterflies; Digestive system; Dominant species; Drug resistance; Ecology; Eggs; Electrophoresis; Enterococcal species; Enterococcus; Enterococcus casseliflavus; Erythromycin; Family relations; Feces; Females; Food; Gastrointestinal system; Gastrointestinal tract; Gel electrophoresis; Genes; Genetic analysis; Genetic relationship; Genetic research; Geographical distribution; Habitat fragmentation; Heliconius erato phyllis; Herbivory; Insects; Intestinal microflora; Lepidoptera; Microbial drug resistance; Microbiology; Microbiota; Microorganisms; Molecular Biology; Molecular typing; Multidrug resistance; Physiological aspects; Pollution; Pulsed-field gel electrophoresis; Rifampin; Siblings; Staphylococcus infections; Strains (organisms); Studies; Virulence; Virulence (Microbiology)
• ISSN: 2167-8359; 2167-8359
• DOI: 10.7717/peerj.8647

Studies evaluating bacteria in insects can provide information about host-microorganism-environment interactions. The gut microbial community has a profound effect on different physiological functions of insects. spp. are part of the gut community in humans and other animals, as well as in insects. The presence and antimicrobial resistance profile of enterococci are well studied in different animals; however, data for (Lepidoptera: Nymphalidae) do not yet exist. Therefore, the aims of this study were to evaluate the distribution of enterococcal species, their antimicrobial resistance profile and virulence genes, and the genetic relationships between enterococci isolated from fecal samples from sibling and non-sibling caterpillars collected from different sites in South Brazil. Three females were captured (two from a forest fragment and one from an urban area), and kept individually in open-air insectaries. Eggs were collected and caterpillars (siblings and non-siblings) were fed daily with leaves. Fecal samples (  = 12) were collected from fifth-instar caterpillars, inoculated in selective medium, and 15 bacterial colonies were randomly selected from each sample. Enterococci were identified by PCR and MALDI-TOF, analyzed by disk diffusion antimicrobial susceptibility tests, and screened for resistance and virulence genes by PCR. The genetic relationships between the strains were determined using pulsed-field gel electrophoresis (PFGE). A total of 178 enterococci strains were identified: (74.15%;  = 132), (21.34%;  = 38), (1.12%;  = 2) and sp. (3.37%;  = 6). High rates of resistance to rifampicin (56%) and erythromycin (31%) were observed; 120 (67.41%) of the isolates showed resistance to at least one antibiotic and six (3.37%) were multidrug-resistant.None of the erythromycin-resistant strains was positive for the (B) and C genes. The virulence genes , , and were observed in 35%, 7%, and 1% of the strains, respectively. PFGE separated the enterococci into 22 patterns, four being composed of strains from sibling caterpillars. was the dominant species in fecal samples of fifth-instar caterpillars. Resistant enterococci strains may be related to environmental pollution or the resistome. The PFGE analysis showed genetic relationships between some strains, suggesting that the enterococci isolated from fecal samples of the sibling caterpillars might have come from common sources, e.g., via diet (herbivory) and/or vertical transmission (through the egg surface).