BACKGROUND Stingless bee honey has great therapeutic potential, especially as an antimicrobial agent. In the present study, we evaluated the in vitro antibacterial potential of honey from Melipona spp. with occurrence in Rio Branco‐AC and Xapuri‐AC from the Amazonian region. Samples were collected from the species Melipona eburnea, Melipona grandis, Melipona flavolineata and Melipona seminigra. The antibacterial activity of the honey samples was tested against standard Gram‐positive and Gram‐negative bacteria and two strains isolated from bovine mastitis. RESULTS In the agar diffusion assay, we observed antibacterial activity for the four honeys against the tested strains. The honey from M. flavolineata showed a minimmum inhibitory concentration (MIC) lower than 3.12% (v/v). The minimum bactericidal concentration values were larger than the MIC for most of the microorganisms tested. Scanning electron microscopy (SEM) showed the damaging effect of the honey of M. flavolineata on Staphylococcus aureus cells, as well as its inhibitory effect on cell division. CONCLUSION The results of the present study demonstrate that the honey from stingless bees possesses in vitro antimicrobial activity against pathogenic bacteria. The effects observed by SEM show that honey from the Amazonian stingless bee M. flavolineata has promising therapeutic potential as a future antimicrobial agent. © 2020 Society of Chemical Industry

Leptospira is a bacteria that causes leptospirosis and is transmitted through water, soil, or mud that is contaminated by the urine of infected animals. Although it is mainly associated with the urban environment, Leptospires also circulate in rural and wild environments. This study aimed to investigate the role of small mammals in leptospirosis epidemiology in the western Amazon, Brazil. In total, 103 animals from 23 species belonging to the orders Didelphimorphia and Rodentia were captured. Blood, kidney, and urine samples were collected and Microscopic Agglutination Test (MAT), lipL32 PCR, secY sequencing, and culturing were conducted. MAT was reactive on 1/15 sera, and no bacterial isolate was obtained. PCR yielded 44.7% positive samples from 16 species. Twenty samples were genetically characterized and identified as L. interrogans (n = 12), L. noguchii (n = 4), and L. santarosai (n = 4). No statistical association was found between the prevalence of infection by Leptospira spp. in small mammals within carrier/hosts species, orders, study area, and forest strata. Our results indicate a high prevalence of pathogenic Leptospira spp. in several rodent and marsupial species and report the first evidence of Leptospira spp. carrier/hosts in the Brazilian Western Amazon.

RESUMO Foram estudadas 135 vacas mestiças, provenientes de 10 rebanhos leiteiros no estado do Acre. O objetivo foi identificar espécies de Staphylococcus isoladas dos quartos mamários de vacas com mastite e, posteriormente, avaliar a capacidade de produção de biofilme pela espécie Staphylococcus chromogenes. A caracterização dos isolados presentes nas amostras encontradas, correspondentes a Staphylococcus sp., foi realizada utilizando-se a técnica do MALDI TOF MS (Matrix Associated Laser Desorption-Ionization - Time of Flight - Mass Spectrometry). Foram identificados: S. chromogenes (36), Staphylococcus saprophyticus (5), S. chromogenes ou Staphylococcus hycus (5), Staphylococcus haemolyticus (4), Staphylococcus epidermidis (3), Staphylococcus hycus (3), Staphylococcus aureus (1), Staphylococcus auriculares (1), Staphylococcus kloosii (1) e Staphylococcus xylosus (1). A espécie S. chromogenes correspondeu a 60% dos isolados do gênero (17 isolados coagularam o plasma de coelho no teste da coagulase em tubo), sendo 83,3% dos isolados (30/36) produtores de biofilme, não estando esse fator de virulência associado ao fenótipo de coagulação do plasma. A identificação desses microrganismos é importante para a elucidação da etiologia da mastite bovina. O alto percentual de S. chromogenes, produtores de biofilme, isolados de vacas com mastite é um achado relevante e pode revelar uma mudança de perfil na colonização de agentes etiológicos causadores dessa enfermidade.

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Staphylococcus species are important pathogens associated to mastitis in lactating cows. Among coagulase‐negative staphylococci, Staphylococcus chromogenes is one of the most prevalent. However, most of the virulence and antimicrobial resistance studies have been done to Staphylococcus aureus isolates. Therefore, the aim of present study was to determine the antimicrobial susceptibility profile of biofilm producing S. chromogenes isolates recovered from cows with mastitis from the Northern region of Brazil. Of one hundred thirty‐five crossbred cows from ten dairy farms with milk production decline, sixty‐seven were with mastitis according to mammary gland clinical examination or California Mastitis Test. Milk samples were collected of these animals to microbiological analysis. Phenotypic tests and MALDI‐TOF were adopted for the bacterial identification. Most of the staphylococci isolates (n=36; 60%) was identified as S. chromogenes. Absorbance‐based method was carried out to determine quantitatively the biofilm production by isolates of this species. Fifteen isolates, with different biofilm production levels, were submitted to the disk diffusion method to ceftiofur, clindamycin, chloramphenicol, ciprofloxacin, enrofloxacin, erythromycin, gentamicin, linezolid, penicillin G, rifampicin, streptomycin and tetracycline. All isolates were susceptible to gentamicin, linezolid and rifampicin. The majority of the isolates were non‐susceptible to penicillin G (n=10; 66.7%), ceftiofur (n=9; 60%), clindamycin (n=9; 60%), enrofloxacin (n=9; 60%) and chloramphenicol (n=8; 53.3%). Multidrug resistance (MDR) was observed to 60% of the isolates. The non biofilm producing isolates (n=3) were susceptible for all antimicrobials, except one was resistance only to penicillin G. MDR was observed among the isolates independently of the biofilm production level (weak, moderate or strong). Isolates susceptible for all antimicrobial agents were also detected among strong and weak biofilm producers. Although few S. chromogenes isolates have been analyzed, high rate of MDR was observed in the present study. Besides antimicrobial resistance these isolates are biofilm producers that is an important virulence strategy. The MDR rate observed may be related to spread of the same strain among the cows of the herds studied. Most studies should be made to this Staphylococcus species due its importance in dairy herds. Moreover, it may contribute to resistance dissemination among other bacterial species, including those of impact in public health, as one source of these genes.Support or Funding InformationDevelopment Agency: Conselho Nacional de Desenvolvimento Científico e Tecnológico‐CNPq, Fundação de Amparo à Pesquisa do Estado do Acre ‐ FAPAC.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.