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“Nostrano-cheeses” are traditional alpine cheeses made from raw cow’s milk in Trentino-Alto Adige, Italy. This study identified lactic acid bacteria (LAB) developing during maturation of “Nostrano-cheeses” and evaluated their potential to produce γ-aminobutyric acid (GABA), an immunologically active compound and neurotransmitter. Cheese samples were collected on six cheese-making days, in three dairy factories located in different areas of Trentino and at different stages of cheese ripening (24 h, 15 days, and 1, 2, 3, 6, and 8 months). A total of 1,059 LAB isolates were screened using Random Amplified Polymorphic DNA-PCR (RAPD-PCR) and differentiated into 583 clusters. LAB strains from dominant clusters (n=97) were genetically identified to species level by partial 16S rRNA gene sequencing. LAB species most frequently isolated were Lactobacillus paracasei, Streptococcus thermophilus, and Leuconostoc mesenteroides. The 97 dominant clusters were also characterized for their ability in producing GABA by high-performance liquid chromatography (HPLC). About 71% of the dominant bacteria clusters evolving during cheeses ripening were able to produce GABA. Most GABA producers were Lactobacillus paracasei but other GABA producing species included Lactococcus lactis, Lactobacillus plantarum, Lactobacillus rhamnosus, Pediococcus pentosaceus, and Streptococcus thermophilus. No Enterococcus faecalis or Sc. macedonicus isolates produced GABA. The isolate producing the highest amount of GABA (80.0±2.7 mg/kg) was a Sc. thermophilus. [ABSTRACT FROM AUTHOR]

In October 2017, two outbreaks of gastroenteritis (GE) occurred among patrons of a cafeteria in Italy in one week. Virological and bacteria investigations on stool samples, environment and food were conducted to identify the infectious agents and the possible source of infection. Forty-five cases occurred in the two outbreaks, including 13 laboratory-confirmed cases of norovirus GI. Nine staff members were interviewed, six were confirmed positive for NoV GI and 3 experienced GE symptoms. Bacteria faecal indicators and other bacteria pathogens were not detected in either environmental swab samples or food. A low level of NoV GII was detected in two environmental swab samples. The same GI.6 strain was identified in cases related to both outbreaks, suggesting a common source of infection. Since the two outbreaks occurred in one week, the NoV contamination could have persisted in the cafeteria. Furthermore, virological investigation revealed confirmed cases among food handlers who had worked at the cafeteria between and during the two outbreaks. Several studies highlighted the importance of excluding symptomatic food handlers to prevent contamination of foods and environment.

To obtain porcine isolates related to Lactobacillus amylovorus, we screened strains from piglet intestine grown on Lactobacillus-specific MRS agar for hybridization to a fluorescent 16S rRNA-targeted DNA probe. Six strains were isolated and further characterized by phenotypic and molecular taxonomic methods. The isolates were Gram-positive, catalase-negative, facultatively anaerobic rods. They had similar phenotypic characteristics and displayed genomic DNA-DNA relatedness values of >78 % to each other, indicating that they belong to a single species. Comparative 16S rRNA gene sequence analysis demonstrated that the novel isolates were members of Lactobacillus rRNA group I, which includes Lactobacillus delbrueckii, the type species of the genus. Based on 16S rRNA gene sequence similarity, Lactobacillus kitasatonis (99 %), Lactobacillus crispatus (98 %) and Lactobacillus amylovorus (97 %) were the nearest relatives of the novel isolates, but their DNA-DNA relatedness was found to be lower than 49 %. One of the isolates, strain OTU171-001T, was further characterized using physiological and biochemical tests. Together, the results enabled genotypic and phenotypic differentiation of strain OTU171-001T from the other species that showed 16S rRNA gene sequence similarity values greater than 97 %. Strain OTU171-001T merits species status and the name Lactobacillus sobrius sp. nov. is proposed. The type strain is OTU171-001T (= DSM 16698T = NCCB 100067T).