No abstract

Minas artisanal cheese, produced in the Campo das Vertentes region of Brazil, is made from raw milk and endogenous starter cultures. Although this cheese is of great historical and socioeconomic importance, little information is available about its microbiological and physical-chemical qualities, or about its beneficial microbiota. This work was aimed at evaluating the qualities of the cheese and the components used for its production, comparing samples collected during the dry and rainy seasons. We also conducted molecular identification and isolated 50 samples of lactic acid bacteria from cheese (n=21), water (n=3), raw milk (n=9), and endogenous starter culture (n=17). The microbiological quality of the cheese, water, raw milk, and endogenous starter culture was lower during the rainy period, given the higher counts of coagulase-positive Staphylococcus and total and thermotolerant coliforms. Enterococcus faecalis was the lactic acid bacteria isolated most frequently (42.86%) in cheese samples, followed by Lactococcus lactis (28.57%) and Lactobacillus plantarum (14.29%). Lactobacillus brevis (5.88%), Enterococcus pseudoavium (5.88%), Enterococcus durans (5.88%), and Aerococcus viridans (5.88%) were isolated from endogenous starter cultures and are described for the first time in the literature. The lactic acid bacteria identified in the analyzed cheeses may inhibit undesirable microbiota and contribute to the safety and flavor of the cheese, but this needs to be evaluated in future research.

Propionibacterium freudenreichii CIRM-BIA 129 (P. freudenreichii wild type, WT) is a probiotic bacterium, which exerts immunomodulatory effects. This strain possesses extractable surface proteins, including SlpB, which are involved in antiinflammatory effect and in adhesion to epithelial cells. We decided to investigate the impact of slpB gene mutation on immunomodulation in vitro and in vivo. In an in vitro assay, P. freudenreichii WT reduced expression of IL-8 (p<0.0001) and TNF-α (p<0.0001) cytokines in LPS-stimulated HT-29 cells. P. freudenreichii ΔslpB, lacking the SlpB protein, failed to do so. Subsequently, both strains were investigated in vivo in a 5-FU-induced mucositis mice model. Mucositis is a common side effect of cytotoxic chemotherapy with 5-FU, characterized by mucosal injury, inflammation, diarrhea, and weight loss. The WT strain prevented weight loss, reduced inflammation and consequently histopathological scores. Furthermore, it regulated key markers, including Claudin-1 (cld1, p<0.0005) and IL-17a (Il17a, p<0.0001) genes, as well as IL-12 (p<0.0001) and IL-1β (p<0.0429) cytokines levels. Mutant strain displayed opposite regulatory effect on cld1 expression and on IL-12 levels. This work emphasizes the importance of SlpB in P. freudenreichii ability to reduce mucositis inflammation. It opens perspectives for the development of probiotic products to decrease side effects of chemotherapy using GRAS bacteria with immunomodulatory surface protein properties.

Lactic acid bacteria were isolated and identified in the faeces of Chinese Crested and Yorkshire terrier pups and their probiotic features were investigated in vitro. Thirty seven isolates were identified as Lactobacillus or Enterococcus. Out of these isolates, 31 were lactic acid bacteria (LAB) and belonged to the species Lactobacillus reuteri (16/37; 43.3%), Lactobacillus animalis (7/37; 18.9%), Lactobacillus acidophilus (3/37; 8.1%), Lactobacillus sanfranciscensis (2/37; 5.4%), Lactobacillus murinus (2/37; 5.4%), and Lactobacillus paraplantarum (1/37; 2.7%), while six other LAB isolates were Enterococcus spp. (6/37; 16.2%). Strains were tested for resistance to gastric acidity (pH 2.5 for 3 h) and bile salts (0.3% ox gall), cell surface hydrophobicity by microbial adhesion to solvents, antagonism against pathogenic bacteria (Staphylococcus aureus, Enterococcus faecalis, Bacillus cereus, Pseudomonas aeruginosa, Escherichia coli, Salmonella enterica serovar Typhimurium and Listeria monocytogenes), production of hydrogen peroxide, and antibiotic susceptibility. Thirty four strains were highly resistant to acidic conditions with slight (18 strains) to moderate (16 strains) growth inhibition by bile salts. Seven isolates had highly hydrophobic cellular surfaces and 28 strains exhibited strong antagonism against the bacterial pathogens tested, although 8 isolates tested against Leptospira interrogans had no effect on pathogen growth. All isolates produced low rates of hydrogen peroxide. Based on these results, two Lactobacillus strains showed promising probiotic-related features and merit investigation as probiotics for dogs.

Coagulase-negative staphylococci (CNS) are important pathogens causing nosocomial infections worldwide with increasing resistance to antimicrobials. The aim of this study was to characterize resistance aspects of CNS isolated from patients with bloodstream infections acquired in hospitals in Belo Horizonte, MG, Brazil. Staphylococcus strains were characterized using repetitive sequence-based polymerase chain reaction (rep-PCR) fingerprinting with (GTG) primer. Phenotypic resistance was analyzed using AST-P5085 card (bioMérieuxVitek). PCR was used to detect mecA, vanA, blaZ, ermA/B/C, aac-aphD, and SCC-mec. For statistical analyses, we used hierarchical cluster, chi-square test (χ), and correspondence. Several clusters were formed within the same species using (GTG) primer, and strains showed resistance to the following antimicrobials: benzylpenicillin (100%); oxacillin (93.1%); gentamicin (36.3%); ciprofloxacin (63.7%); moxifloxacin (32.7%); norfloxacin (81.0%); erythromycin (86.2%); clindamycin (75.8%); linezolid, teicoplanin and vancomycin (1.7%); tigecycline (0%); fusidic acid (10.35%); rifampicin (13.7%); and trimethoprim/sulfamethoxazole (46.5%). Regarding genotypic analyses, 40%, 0%, 78%, 42%, 100%, 24%, and 30% were positive for mecA, vanA, blaZ, ermA, ermB, ermC, and aac-aphD, respectively. Regarding staphylococcal cassette mec (SCCmec) type, 3.4% presented type I; 5.0% type II; 27.1% type III; 20.3% type IIIA; and 32.2% type IIIB. Six clusters were formed and frequency distributions of resistant strains to oxacillin, gentamicin, ciprofloxacin, moxifloxacin, norfloxacin, erythromycin, clindamycin, linezolid, teicoplanin, vancomycin, fusidic acid, rifampicin, and trimethoprim/sulfamethoxazole, and mecA, blaZ, ermC, aac-aphD, and SCCmec type differed (p < 0.001). In conclusion, the strains investigated in this study were multidrug resistant and carried multiple antibiotic resistance genes.