Synergistic growth effect among bacteria recovered from root canal infections

The objective of this study was to determine the ecological relationships between bacterial species that colonize infected root canals. Root canal bacteria recovered from one patient with pulp canal necrosis were evaluated in vitro for synergistic and antagonistic activities determined by mono and co-culture growth kinetics and the production of bacteriocin-like substances using the double layer diffusion method. Peptostreptococcus prevotii triggered a significant increase of Fusobacterium nucleatum growth, while the former bacteria did not affect the growth of P. prevotii. The bacterial species did not produce antagonism activity against itself or against any of the other two species. Despite many studies have demonstrated the capability of root canal microorganisms to produce antagonistic substances, these in vitro experimental tests show the synergistic effect of P. prevotii on the growth of F. nucleatum.

Distribution, detection of enterotoxigenic strains and antimicrobial drug susceptibility patterns of Bacteroides fragilis group in diarrheic and non-diarrheic feces from Brazilian infants

Despite the importance of gastrointestinal diseases and their global distribution, affecting millions of individuals around the world, the role and antimicrobial susceptibility patterns of anaerobic bacteria such as those in the Bacteroides fragilis group (BFG) are still unclear in young children. This study investigated the occurrence and distribution of species in the BFG and enterotoxigenic strains in the fecal microbiota of children and their antimicrobial susceptibility patterns. Diarrheic (n=110) and non-diarrheic (n=65) fecal samples from children aged 0-5 years old were evaluated. BFG strains were isolated and identified by conventional biochemical, physiological and molecular approaches. Alternatively, bacteria and enterotoxigenic strains were detected directly from feces by molecular biology. Antimicrobial drug susceptibility patterns were determined by the agar dilution method according to the guidelines for isolated bacteria. BFG was detected in 64.3 percent of the fecal samples (55 percent diarrheic and 80.4 percent non-diarrheic), and 4.6 percent were enterotoxigenic. Antimicrobial resistance was observed against ampicillin, ampicillin/sulbactam, piperacillin/tazobactam, meropenem, ceftriaxone, clindamycin and chloramphenicol. The data show that these bacteria are prevalent in fecal microbiota at higher levels in healthy children. The molecular methodology was more effective in identifying the B. fragilis group when compared to the biochemical and physiological techniques. The observation of high resistance levels stimulates thoughts about the indiscriminate use of antimicrobial drugs in early infancy. Further quantitative studies are needed to gain a better understanding of the role of these bacteria in acute diarrhea in children.

Isolamento e identificação da microbiota periodontal de cães da raça Pastor Alemão / Isolate and identify of periodontal microbiota of German Shepherd dogs

A microbiota indígena gengival de cães não está totalmente descrita, sendo sua identificação uma etapa importante no estabelecimento da etiopatogenia e terapia da doença periodontal. O objetivo deste trabalho foi isolar e identificar a microbiota periodontal de cães da raça Pastor Alemão, considerando sítios saudáveis e com doença periodontal. Foram utilizados 29 cães, com idade variando de três a seis anos, sendo analisados espécimes clínicos de sítios periodontais saudáveis de 12 cães e sítios com periodontite de outros 17. Foram isoladas 672 amostras microbianas, com predomínio dos gêneros Pasteurella, Staphylococcus, Porphyromonas e Fusobacterium. A microbiota dos sítios saudáveis equiparou-se à dos sítios doentes, tratando-se de uma microbiota indígena. A microbiota dos sítios doentes apresentou-se aumentada em relação a dos sítios saudáveis, indicando mudança do ambiente do sítio periodontal.

Dominant culturable bacterial microbiota in the digestive tract of the American black vulture (Coragyps atratus Bechstein 1793) and search for antagonistic substances

As bactérias anaeróbias estritas e facultativas cultiváveis do trato digestivo de seis urubus (Coragyps atratus Bechstein 1793) foram isoladas e identificadas. Após a captura, as aves receberam uma alimentacão de baixa contaminacão durante uma semana para eliminar possíveis microorganismos alóctonos. A seguir, amostras colhidas na língua, estomago e intestinos foram pesadas, submetidas a diluicões decimais numa câmara anaeróbia, inoculadas em meios de cultura e incubadas em aerobiose e anaerobiose a 37ºC para enumeracão, isolamento e identificacão. As bactérias isoladas foram usadas posteriormente como produtoras e reveladoras para detectar possíveis fenômenos de antagonismo. A populacão bacteriana total ao longo do trato digestivo variou de 3,46 n 0,39 log UFC/g no estômago até 10,75 n 0,37 log UFC/g no intestino distal. Algumas bactérias foram isoladas pela primeira vez do trato digestivo de C. atratus: Actinomyces bovis, Lactobacillus cellobiosus, Micrococcus luteus, Neisseria sicca, Clostridium bifermentans, Enterobacter agglomerans, Peptostreptococcus sp., Sarcina sp., Serratia odorifera, and Shigella flexneri. Associacões entre microorganismos foram observadas durante o isolamento em dois casos, um envolvendo A. bovis e N. sicca, e o outro envolvendo A. bovis e um bastonete Gram-negativo. Hetero-, iso- e autoantagonismos foram observados, sugerindo um papel ecológico para esses microorganismos em termos de autocontrole populacional e de barreira ambiental no trato digestivo dessas aves.