Biodiversity of dairy Propionibacterium isolated from dairy farms in Minas Gerais, Brazil.

Dairy propionibacteria are used as ripening cultures for the production of Swiss-type cheeses, and some strains have potential for use as probiotics. This study investigated the biodiversity of wild dairy Propionibacteria isolates in dairy farms that produce Swiss-type cheeses in Minas Gerais State, Brazil. RAPD and PFGE were used for molecular typing of strains and MLST was applied for phylogenetic analysis of strains of Propionibacterium freudenreichii. The results showed considerable genetic diversity of the wild dairy propionibacteria, since three of the main species were observed to be randomly distributed among the samples collected from different farms in different biotopes (raw milk, sillage, soil and pasture). Isolates from different farms showed distinct genetic profiles, suggesting that each location represented a specific niche. Furthermore, the STs identified for the strains of P. freudenreichii by MLST were not related to any specific origin. The environment of dairy farms and milk production proved to be a reservoir for Propionibacterium strains, which are important for future use as possible starter cultures or probiotics, as well as in the study of prevention of cheese defects.

Physiological and functional characteristics of Propionibacterium strains of the poultry microbiota and relevance for the development of probiotic products.

The prevention and control of pathogens colonization through probiotics administration in poultry feeding is of increasing interest. The genus Propionibacterium is an attractive candidate for the development of probiotic cultures as they produce short chain fatty acids (SCFA) by carbohydrates fermentation. The presence of strains of this genus in hens of conventional production systems and backyard hens was investigated. Propionibacteria were isolated from the intestine and identified by physiological and biochemical tests. PCR amplification of the 16S rRNA gene of the isolates was performed and products were compared with sequences from databases. The presence of the genus Propionibacterium was demonstrated in 26% of hens and Propionibacterium acidipropionici and Propionibacterium avidum were the identified species. A comparative study of their physiological and functional characteristics was performed. P. acidipropionici strains were the most resistant to in vitro gastrointestinal digestion, but the adhesion to intestinal tissue was strain dependent. Some differences were found between both species with respect to their growth and SCFA production in an in vitro cecal water model, but all the strains were metabolically active. The production of SCFA in cecal slurries inoculated with the strain P. acidipropionici LET 105 was 30% higher than in non-inoculated samples. SCFA concentrations obtained were high enough to inhibit Salmonella enterica serovar Enteritidis when assayed in a cecal water model. P. acidipropionici LET 105 was also able to compete with Salmonella for adhesion sites on the intestinal mucosa in ex vivo assays. Results contribute to the knowledge of the species diversity of the genus Propionibacterium in the intestine of poultry and provide evidence of their potential for probiotics products development.

Distinct cutaneous bacterial assemblages in a sampling of South American Amerindians and US residents.

The human skin harbors complex bacterial communities. Prior studies showing high inter-individual variation focused on subjects from developed countries. We therefore compared cutaneous bacterial communities of Amerindians in the Venezuelan Amazon with subjects in the United States. Forearm skin specimens were studied from healthy Amerindians in Platanillal village in Amazonas State, and from healthy persons in New York and Colorado. All skin sampling used similar swab/buffer techniques. Multiplexed V2-targeted 16S rRNA gene pyrosequencing yielded high quality sequences from 112 samples. The results show 20 phyla, with three (Proteobacteria, Firmicutes, Actinobacteria) predominating. US residents and Venezuelan Amerindians had significantly different forearm skin bacterial community compositions, with United States dominated by Propionibacterium. Among the Amerindians, there was a deep split based on bacterial community membership, with 30 and 42 samples, respectively, falling into each of the two groups, not associated with age, gender, or body mass index. One Amerindian group had diversity similar to the United States, but was dominated by Staphylococcus rather than Propionibacterium. The other Amerindian group was significantly more diverse and even than the US or the other Amerindian group, and featured a broad range of Proteobacteria. The results provide evidence that ethnicity, lifestyle and/or geography are associated with the structure of human cutaneous bacterial communities.

Persistent extraradicular infection in root-filled asymptomatic human tooth: scanning electron microscopic analysis and microbial investigation after apical microsurgery.

INTRODUCTION: Procedural accidents have a negative effect on healing and might contribute to the persistence of infections in inaccessible apical areas, requiring surgical intervention. This report describes a case of persistent apical periodontitis of a lower left first molar associated with the sinus tract and a periapical lesion that required nonsurgical endodontic retreatment and apical surgery for resolution. METHODS: The tooth had received endodontic treatment 3 years ago and had to be retreated using the crown-down technique with chemical auxiliary substance (2% chlorhexidine gel), foramen patency, and enlargement and was filled in a single appointment. The occlusal access cavity was immediately restored with composite resin. After 1 month, it could be observed that the sinus tract persisted and, radiographically, the lesion remained unaltered. Therefore, endodontic microsurgery was indicated. Apical microsurgery was performed under magnification with the use of a dental operating microscope including apicectomy, root end with ultrasound, and sealing with mineral trioxide aggregate. A microbiological sample was collected from the apical lesion. The resected distal root apex was observed by scanning electron microscopy. RESULTS: The following species were detected: Actinomyces naeslundii and Actinomyces meyeri, Propionibacterium propionicum, Clostridium botullinum, Parvimonas micra, and Bacteroides ureolyticus; scanning electron microscopic analysis revealed bacterial biofilm surrounding the apical foramen and external radicular surface. Gutta-percha overfilling at the apex because of a zip caused during initial endodontic treatment could be observed. A 6-month follow-up showed apparent radiographic periapical healing, which progressed after 24 months. CONCLUSION: Gram-positive anaerobic bacteria and extraradicular biofilm seem to participate in the maintenance of persistent periapical pathology, and endodontic retreatment followed by periapical microsurgery proved to be a successful alternative in the resolution of persistent extraradicular infections.

Assessing survival of dairy propionibacteria in gastrointestinal conditions and adherence to intestinal epithelia.

The genus Propionibacterium consists of two principal groups, cutaneous and classical or dairy. Cutaneous species are predominant members of the microbial population of human skin and have also been isolated from the feces of humans and other vertebrate animals. They are often considered opportunistic organisms and have been occasionally associated with infections in humans. Dairy propionibacteria are microorganisms extensively used in the industry for manufacture of Swiss-type cheeses and biological production of propionic acid and vitamin B12. They can be isolated from soil, vegetables, silage, raw milk, and dairy products such as kefir and different cheeses with "eyes."In the last decade, several studies have demonstrated probiotic properties for members of the genus Propionibacterium. The effects claimed are based on the production of bacteriocins, vitamins, stimulation of growth of other colonic bacteria like bifidobacteria, beneficial modification of the composition and metabolic activities of the intestinal microflora, immunomodulation, and antimutagenic activity. It is thought that to produce many of these health benefits, the probiotic microorganisms must be able to survive the transit through the hostile conditions of the gastrointestinal tract (GIT) and remain at high levels in the intestine, avoiding removal by peristaltic contractions of the gut. In this sense, microorganisms with a short generation time or the ability to adhere to the intestinal mucosa will survive for prolonged periods in the body of the host. Therefore, two desirable properties for probiotic microorganisms are (1) resistance to gastric acidity, bile, and pancreatic enzymes; and (2) adhesion ability to mucosal surfaces. Dairy bacteria are traditionally not considered to persist as normal inhabitants of the human intestinal tract. Therefore, survival under GIT conditions and adherence are important properties to be considered, and tests to study them would be useful tools. In the present chapter we describe the methods used in our laboratory to assess survival, metabolic activity, and adhesion of dairy propionibacteria to intestinal epithelial cells after gastrointestinal digestion.

Identification of anaerobic nonsporeforming gram-positive bacilli by biochemical tests and gas-liquid chromatography.

There are many methods to identify anaerobic nonsporeforming bacilli: histological, bacteriological (biochemical test, microsystem API 20 A), serological, cell wall composition analysis, molecular methods and gas-liquid chromatography (GLC). A comparison between biochemical tests and gas-liquid chromatography was made in this study for the identification of this group of microorganisms. GLC conditions were established with the aid of reference strains. These conditions were then applied to ten strains which were previously identified by biochemical tests. Strains were grown in PYG broth and fermentation end products were analyzed, volatile and non volatile fatty acids. Their qualitative determination was made by comparing the retention time of known standards and the chromatographic pattern of reference strains. In addition, a semiquantitative analysis was made. The results of identification by biochemical tests were: five strains belonged to Actinomyces genus; three were Propionibacterium acnes; one Propionibacterium granulosum and one P. propionicum. By the GLC only seven strains were identified: four were Actinomyces and three P. acnes. Only six strains showed identification correlation by both biochemical tests and GLC. GLC is a presumptive identification method that can be used along with other complementary tests for a definitive identification at genus level.

A scanning electron microscopic evaluation of in vitro dentinal tubules penetration by selected anaerobic bacteria.

In vitro root canal dentinal tubule invasion by selected anaerobic bacteria commonly isolated from endodontic infections was evaluated. Dentinal cylinders obtained from bovine incisors were inoculated with bacteria, and microbial penetration into tubules was demonstrated by scanning electron microscopy. The results indicated that all bacterial strains tested were able to penetrate into dentinal tubules, but to different extents.

Anaerobios en sinusitis maxilar aguda / Anaerobios in acute maxillary sinusitis

Se examinó bacteriológicamente 56 muestras de secreción sinusal obtenidas por punción aspirativa de senos maxilares de 39 pacientes adultos con evidencia clínica y radiológica de sinusitis maxilar aguda. Las muestras se cultivaron con técnicas microbiológicas habituales para pesquisa de gérmenes aerobios y anaerobios. La positividad del cultivo de las punciones practicadas fue de un 62,5 por ciento demostrándose la presencia de anaerobios en el 21,4 por ciento de éstas y encontrándose anaerobios puros en el 14,3 por ciento . Los gérmenes anaerobios mas frecuentes aislados fueron el Peptostreptococcus y el Propionibacterium, bacterias habituales de la flora buconasal

Bilicultivo de colecistectomizados en el Hospital Nacional Edgardo Rebagliati Martins del IPSS / Cholescistectomized biliculture at the Hospital Nacional Edgardo Rebagliati Martins del IPSS

Se hicieron bilicultivos a 111 pacientes de ambos sexos, colecistectomizados entre mayo y noviembre de 1984, en el Hospital Nacionar "E. Rebagliati M." del I.P.S.S.. El 360% fue del sexo masculino y el 64% del sexo femenino. El 37.8% de los bilicultivos resultaron positivos, el 50% de los bilicultivos hechos a los hombres resultaron positivos mientras que en las mujeres fue sólo el 31%. La positividad estuvo más relacionada a la myor edad. Se relaciona la positividad con la patología vesicular encontrada. La bacteria más frecuentemente aislada fue Escherichia coli. Se identifica por primera vez a Plesiomonas shigelloides en bilicultivos. En el 3.6% del total de cultivos se aisla Salmonella typhi--paratyphy A. El 5% de los jombres y el 2.8% de las mujeres portadoras de S. typhy-paratyphi A

New types of Propionibacterium from lepromatous nodules and deep layers of normal skin

While attempting to grow M. leprae in an innovated culture medium, organisms similar to Propionibacterium, but not conforming to any of its documented types, were isolated from lepromatous nodules in 10 out of 15 leprosy cases. Subsequently, a similar organism could also be isolated from the depth of the skin of normal persons but not from their skin surface. The possible role of Propionibacterium in the pathogenesis of leprosy or other skin infections has been discussed.