Bactérias pulmonares de morcegos do cerrado brasileiro: diversidade e suscetibilidade a antimicrobianos

Abstract

Bats play key ecological roles, with broad adaptability to different environments, favoring contact with humans and mitigating the role of these animals as potential reservoirs of pathogens. Pathogenic bacteria, already isolated from bats such as Bartonella spp., Leptospira sp., Rickettsia rickettsii, and Escherichia coli, reinforce the importance of investigating the biology, ecology, and health relevance of these animals. Recent studies show that, contrary to what was previously believed, lungs are not sterile and can harbor stable bacterial communities with important functions. Thus, the present study aimed to analyze the composition of the lung microbiota of bats from the Brazilian Cerrado and determine the susceptibility profile of isolated bacterial strains to antimicrobials. The bats were collected using mist nets in the municipalities of Caxias/MA, Floriano/PI, and Barão de Grajaú/MA, all of which belong to the Cerrado biome, and were sent to the Genetics Laboratory/LABGEN, based at the GENBIMOL UEMA complex, Caxias Campus, for subsequent laboratory procedures to identify the bat species and obtain the pulmonary bacteria. Lung bacteria were obtained using two approaches: a culture-independent approach and a culture-dependent approach. In the culture-independent approach, DNA was extracted directly from the bats' lung tissue, followed by amplification of the 16S rRNA gene to verify the presence or absence of bacteria. In the culture-dependent approach, a swab was taken from the lung, and the bacteria were cultured on plates

containing sheep blood agar, nutrient agar, eosin-methylene blue agar, and Mueller- Hinton agar. DNA was extracted from the cultured bacteria, and the 16S rRNA gene was

amplified and sequenced. Penicillin was added to the nutrient agar to select bacteria resistant to β-lactams, and resistance to other antibiotics was evaluated using the disc diffusion method (Kirby–Bauer) on Mueller–Hinton agar. Morphological, molecular, and ecological markers were used to identify and classify the bats. As a result, 21 bat species were recorded in the sampled municipalities, distributed across five families, with a predominance of the species Carollia perspicillata, family Phyllostomidae. Of the 21 species recorded, 11 showed bacterial presence, where molecular analysis of the lungs confirmed the presence of bacterial DNA in eight bat species: Rhynophylla pumilio, Molossus molossus, Carollia perspicillata, Artibeus cinereus, Phyllostomus hastatus, Glossophaga soricina, Sturnira lilium, Artibeus planirostris, and plaque analysis in four species, namely: Eumops glaucinus, Myotis riparius, C. perspicillata, and Artibeus lituratus. Only four bacterial species were isolated from the 11 bat species: Bacillus subtilis, Staphylococcus saprophyticus, Acinetobacter spp., and Gordonia spp., the latter being recorded for the first time in bat lungs. It was possible to isolate and identify bacteria that presented distinct antimicrobial susceptibility profiles, with emphasis on resistance to penicillin and other β-lactams, as well as an intermediate response to polymyxin B by Acinetobacter spp., suggesting the occurrence of adaptive mechanisms even in non-clinical environments.