Screening of colistin-resistant bacteria in livestock animals from France

Abstract Colistin is frequently used as a growth factor or treatment against infectious bacterial diseases in animals. The Veterinary Division of the European Medicines Agency (EMA) restricted colistin use as a second-line treatment to reduce colistin resistance. In 2020, 282 faecal samples were collected from chickens, cattle, sheep, goats, and pigs in the south of France. In order to track the emergence of mobilized colistin resistant ( mcr ) genes in pigs, 111 samples were re-collected in 2021 and included pig faeces, food, and water from the same location. All samples were cultured in a selective Lucie Bardet Jean-Marc Rolain (LBJMR) medium and colonies were identified using MALDI-TOF mass spectrometry and then antibiotic susceptibility tests were performed. PCR and Sanger sequencing were performed to screen for the presence of mcr genes. The selective culture revealed the presence of 397 bacteria corresponding to 35 different bacterial species including Gram-negative and Gram-positive. Pigs had the highest prevalence of colistin-resistant bacteria with an abundance of intrinsically colistin-resistant bacteria and from these samples one strain harbouring both mcr- 1 and mcr- 3 has been isolated. The second collection allowed us to identify 304 bacteria and revealed the spread of mcr- 1 and mcr- 3 in pigs. In the other samples, naturally, colistin-resistant bacteria were more frequent, nevertheless the mcr- 1 variant was the most abundant gene found in chicken, sheep, and goat samples and one cattle sample was positive for the mcr- 3 gene. Animals are potential reservoir of colistin-resistant bacteria which varies from one animal to another. Interventions and alternative options are required to reduce the emergence of colistin resistance and to avoid zoonotic transmissions

Use of the proteomic tool MALDI-TOF MS in termite identification

International audienceAbstract Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-TOF MS) has proved effective for the identification of many arthropods. A total of 432 termite specimens were collected in Mali, Cote d’Ivoire, Togo, Senegal, Switzerland and France. Morphologically, 22 species were identified, including Ancistrotermes cavithorax, Amitermes evuncifer , Cryptotermes brevis , Cubitermes orthognathus , Kalotermes flavicollis , Macrotermes bellicosus , Macrotermes herus , Macrotermes ivorensis , Macrotermes subhyalinus , Microcerotermes parvus , Microtermes sp., Odontotermes latericius , Procubitermes sjostedti , Promirotermes holmgreni , Reticulitermes grassei , Reticulitermes lucifugus , Reticulitermes santonensis , Trinervitermes geminatus , Trinervitermes occidentali s, Trinervitermes togoensis , Trinervitermes sp., Trinervitermes trinervoides and Trinervitermes trinervius . Analysis of MALDI-TOF MS spectra profiles from termites revealed that all were of high quality, with intra-species reproducibility and inter-species specificity. Blind testing of the spectra of 389 termites against our updated database with the spectra of 43 specimens of different termite species revealed that all were correctly identified with log score values (LSVs) ranging from 1.65 to 2.851, mean 2.290 ± 0.225, median 2.299, and 98.4% (383) had LSVs > 1.8. This study is the first on the use of MALDI-TOF for termite identification and shows its importance as a tool for arthropod taxonomy and reinforces the idea that MALDI-TOF MS is a promising tool in the field of entomology

Survey of bed bug infestations in homeless shelters in southern France

International audienceAbstract Bed bug has become a major public health pest worldwide. Infestation may result in numerous negative health effects. Homeless shelters are one of the most habitats that can be infested with bed bugs, a few studies have focused on bed bug infestations in these settings. We conducted a survey of infestations of bed bugs in a homeless shelter in southern France, using an innovative seven-level scale (0–6) to assess the degree of infestation, MALDI TOF-MS to identify bed bugs, and a biomolecular tool to detect bacteria. Bed bug infestations were documented in 13% (9/68) of investigated rooms. A total of 184 bed bugs were collected and morphologically identified as Cimex lectularius . MALDI TOF–MS analysis allowed us to obtain high-quality MS spectra for all 184 specimens, to correctly identify all specimens, and included 178/184 (97%) Log Score Values higher than 1.8. Among the bacteria tested, Wolbachia sp. DNA was found in 149/184 (81%) of the bed bugs, and one sample was positive for Coxiella burnetii , the agent of Q fever. Our study is the first of its kind that offers new perspectives for increasing public awareness of the conditions in homeless shelters

Identification of termites from Gabon using MALDI-TOF MS

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