Meningitis due to Weissella Confusa.

Bacterial meningitis is a life-threatening condition that should be addressed as an emergency. The typical culprit microorganisms are targeted empirically with ceftriaxone and vancomycin, in the absence of an immunocompromised state. In this case report, however, we are describing a case of meningitis secondary to Weissella confusa, bacteria inherently resistant to the two drugs commonly used to empirically treat meningitis. Weissella spp. are Gram-positive, catalase-negative coccobacilli and an infrequent cause of infection in humans. Bacteremia followed by endocarditis are the typical clinical manifestations of W. confusa in humans. Other reported manifestations include post-operative osteomyelitis, thumb abscess, infected prosthetic joint, infected peritoneal fluid and peritonitis. To our knowledge, this is the first case of meningitis due to Weissella confusa in the literature. Therefore, we conclude that the isolation of Gram-positive coccobacilli resistant to vancomycin, especially in an immunocompromised host, should raise the suspicion of W. confusa.

Effects of Weissella cibaria CMU on Halitosis and Calculus, Plaque, and Gingivitis Indices in Beagles.

Weissella (W.) cibaria strain Chonnam Medical University (CMU) has shown oral colonizing ability and inhibitory effects on the formation of volatile sulfur compounds (VSCs) in vitro studies. The present study was conducted to analyze the effects of the W. cibaria CMU on canine oral health. Halitosis, calculus, plaque, gingivitis, and intraoral microbiota were assessed in 3 groups: control (maltodextrin), W. cibaria CMU low concentration (CMU-L, 2 × 107 colony forming unit [CFU]), and high-concentration (CMU-H, 2 × 109 CFU). Halitosis was analyzed using both organoleptic evaluation and measurement of VSCs. Intraoral microbiota were analyzed by real-time polymerase chain reaction. From week 4, the total VSC level in the CMU-H group (4.0 ± 1.30 ng/10 mL) was significantly lower than in the control group (6.3 ± 2.28 ng/10 mL). Significant reduction in methyl mercaptan in the CMU-treated groups was also observed. In addition, the plaque index in the CMU-treated groups was significantly decreased. The CMU-treated groups showed significant decreases in Fusobacterium nucleatum, Porphyromonas gingivalis, Prevotella intermedia, and Tannerella forsythia and demonstrated the colonizing ability of W. cibaria CMU in the oral cavity. We demonstrated that W. cibaria CMU suppresses halitosis, colonizes the oral cavity, and inhibits the proliferation of malodor-causing oral bacteria in beagles. According to these results, we expect that W. cibaria CMU could be a new oral hygiene solution by reducing VSC production and inhibiting the growth of oral harmful bacteria in companion animals.

Purification and characterization of exopolysaccharide produced by Weissella cibaria YB-1 from pickle Chinese cabbage.

An exopolysaccharide (EPS) was produced by Weissella cibaria YB-1 isolated from pickle Chinese cabbage. The EPS was purified and characterized. The monosaccharide composition of the EPS was glucose, and its molecular mass was 3.89 × 106 Da, as determined by gas chromatography (GC) and high performance liquid chromatography (HPLC). The structural characterization of purified EPS determined by Fourier transform infrared (FT-IR) spectra and nuclear magnetic resonance (NMR) spectra demonstrated that W. cibaria YB-1 synthesized a linear dextran that predominately had α-(1 → 6) glycosidic linkages with only a few α-(1 → 3) (4.3%) linked branches. The water solubility index (WSI), water holding capacity (WHC) and emulsifying activity (EA) of YB-1 dextran were 95.23 ±â€¯4.45, 287.84 ±â€¯16.23 and 84.43 ±â€¯3.65%, respectively. The in-vitro antioxidant activities of the dextran showed good scavenging effects on superoxide anion radical and hydroxyl radical.

Isolation characterization, virulence potential of Weissella ceti responsible for weissellosis outbreak in rainbow trout (Oncorhynchus mykiss) cultured in Mexico.

Weissella ceti, a Gram-positive nonmotile bacterium, is currently an emerging pathogen within rainbow trout (Oncorhynchus mykiss) farms in China, Brazil, the United States, and Japan. This study is the first to isolate, identify, and characterize W. ceti isolates from rainbow trout farmed in Mexico. In late 2015, a severe disease outbreak caused a 60% mortality rate among 20,000 fish. The diseased rainbow trout (100-300 g average) exhibited severe cachexia, body darkening, abdominal distension, exophthalmia, haemorrhages, and corneal opacity. Internally, diseased fish had pale gills; multifocal, disseminated whitish spots on the liver; haemorrhages in the swim bladder, ovary, and on the parietal surface of the muscle; and hearts with pseudo-membrane formation. Histologically, lesions were characterized by corneal oedema, degenerative and necrotic hepatitis, and meningitis. A brain (W-1) and kidney (W-2) isolate were identified as W. ceti through polyphasic taxonomy, which included phenotypic characterization and 16S rRNA sequencing. RAPD and ERIC-PCR analyses demonstrated genetic homogeneity among the Mexican isolates. Virulence tests in rainbow trout through intraperitoneal W. ceti injections at concentrations of 1 × 104 , 1 × 105 , and 1 × 106 CFU per fish resulted in cumulative mortality rates of 25%, 62.5%, and 87.5%, respectively, as well as the same clinical signs of hemorrhagic septicaemia as were recorded for the natural outbreak. The present report is the first to confirm the presence of W. ceti in Mexico, thus extending the known geographical distribution of this pathogen across the Americas.

Genomic insights into the evolution and ecology of botulinum neurotoxins.

Clostridial neurotoxins, which include botulinum neurotoxins (BoNTs) and tetanus neurotoxins, have evolved a remarkably sophisticated structure and molecular mechanism fine-tuned for the targeting and cleavage of vertebrate neuron substrates leading to muscular paralysis. How and why did this toxin evolve? From which ancestral proteins are BoNTs derived? And what is, or was, the primary ecological role of BoNTs in the environment? In this article, we examine these questions in light of recent studies identifying homologs of BoNTs in the genomes of non-clostridial bacteria, including Weissella, Enterococcus and Chryseobacterium. Genomic and phylogenetic analysis of these more distantly related toxins suggests that they are derived from ancient toxin lineages that predate the evolution of BoNTs and are not limited to the Clostridium genus. We propose that BoNTs have therefore evolved from a precursor family of BoNT-like toxins, and ultimately from non-neurospecific toxins that cleaved different substrates (possibly non-neuronal SNAREs). Comparison of BoNTs with these related toxins reveals several unique molecular features that underlie the evolution of BoNT's unique function, including functional shifts involving all four domains, and gain of the BoNT gene cluster associated proteins. BoNTs then diversified to produce the existing serotypes, including TeNT, and underwent repeated substrate shifts from ancestral VAMP2 specificity to SNAP25 specificity at least three times in their history. Finally, similar to previous proposals, we suggest that one ecological role of BoNTs could be to create a paralytic phase in vertebrate decomposition, which provides a competitive advantage for necrophagous scavengers that in turn facilitate the spread of Clostridium botulinum and its toxin.

Literature-based safety assessment of an agriculture- and animal-associated microorganism: Weissella confusa.

Although Weissella confusa was established as a species over 25 years ago, it has been understudied until very recently. Several independent observations have driven the recent interest in this important microorganism. First, this Leuconostoc-like species of Lactic Acid Bacteria is associated with agricultural environments, many spontaneous food fermentations-especially carbohydrate-rich vegetable fermentations-and silage. Second, Weissella confusa are members of the autochthonous microbiota of healthy humans and livestock. Third, Weissella confusa-in a strain-specific fashion-are postulated to be good candidates for the development of novel direct-fed microbial products. Fourth, Weissella confusa-in a strain-specific fashion-have been described as opportunistic pathogens-especially in immunocompromised individuals. Last, a distantly related species (Weissella ceti) is the etiologic agent of weissellosis, a disease that affects farmed fish that are important for commercial aquaculture. The purpose of this literature-based safety assessment is to consolidate findings from primary research related to Weissella confusa and its natural associations with and effects on animals, humans, and their agricultural environments. Based on these assessments, it is reasonable to conclude that many Weissella confusa are safe for use in direct-fed microbial products for poultry.

Selection of new lactic acid bacteria strains bearing probiotic features from mucosal microbiota of healthy calves: Looking for immunobiotics through in vitro and in vivo approaches for immunoprophylaxis applications.

From the birth, since their mucosal microbiota and immune system are not fully developed, newborn calves are susceptible to several mucosal pathogenic microorganisms. Operating through humoral and non-humoral mechanisms in the host, several lactic acid bacteria strains bearing probiotic features are often employed in livestock as food supplement, improving animal production performance, promoting health and reducing the severity of mucosal infections. Accordingly, we isolated, species-level identified and screened for their probiotic potentials seventy lactic acid bacteria strains from upper airway, vaginal and intestinal mucosa of healthy calves. Based on in vitro approaches, we selected three strains: Lactobacillus fermentum V3B-08 isolated from upper airway mucosa, Weissella hellenica V1V-30 isolated from vaginal mucosa and Lactobacillus farciminis B4F-06 isolated from intestinal mucosa were used to mono-colonize germ-free mice in the same site in which these strains were isolated, aiming to characterize their immunomodulatory features. These strains were able to colonize germ-free mice mucosa and trigger sIgA synthesis at a local level, in addition to stimulating, in different ways, adaptive immune responses at a systemic level.

Weissella sp. outbreaks in commercial rainbow trout (Oncorhynchus mykiss) farms in Brazil.

The genus Weissella contains 14 bacterial species that usually occur in nutrient-rich environments and in fermented foods and beverages. Outbreaks of hemorrhagic septicemia were reported in three commercial rainbow trout (Oncorhynchus mykiss) farms in Brazil in 2008 and 2009. Seventy-seven Gram-positive isolates were obtained from 41 diseased fish from these farms. The bacterial strains were identified as Weissella at the genus level using biochemical tests, Weissella genus-specific PCR, and 16S rRNA sequencing. To evaluate potential routes of infection, rainbow trout juveniles were experimentally infected with the pathogen. In addition, the resistance of the pathogen to five antibiotics was tested, and provisional epidemiological cut-off values were calculated using the normalized resistance interpretation (NRI). All isolates presented similar phenotypic profiles and positive reactions for Weissella genus-specific PCR. The 16S rRNA sequences of the Brazilian strains showed 100% similarity with sequences of Chinese isolates that previously were identified as the first case of Weissella sp. infection in fish. The disease was successfully reproduced in the laboratory by intraperitoneal injection, immersion, and cohabitation between diseased and healthy fish. All isolates were resistant to sulfonamide, and based on NRI analysis, one, two, and three isolates were classified as non-wild-type (NWT) for erythromycin, oxytetracycline, and norfloxacin, respectively. This is the first description of multiple cases of Weissella sp. infection in rainbow trout farms outside of China, of infectious routes for the disease, and of provisional epidemiological cut-off values for resistance of these bacteria to four antibiotics.