A total of 98 previously characterized and serotyped L. monocytogenes strains, comprising 32 of 1/2a; 20 of 1/2b and 46 of 4b serotype, from clinical and food sources were studied for their capability to form a biofilm. The microtiter plate assay revealed 62 (63.26%) strains as weak, 27 (27.55%) strains as moderate, and 9 (9.18%) strains as strong biofilm formers. Among the strong biofilm formers, 6 strains were of serotype 1/2a and 3 strains were of serotype 1/2b. None of the strain from 4b serotype exhibited strong biofilm formation. No firm correlation (p = 0.015) was noticed between any serotype and respective biofilm formation ability. Electron microscopic studies showed that strong biofilm forming isolates could synthesize a biofilm within 24 h on surfaces important in food industries such as stainless steel, ceramic tiles, high-density polyethylene plastics, polyvinyl chloride pipes, and glass. Cell enumeration of strong, moderate, and weak biofilm was performed to determine if the number of cells correlated with the biofilm-forming capabilities of the isolates. Strong, moderate, and weak biofilm showed 570±127× 103 cells/cm2, 33±26× 103 cells/cm2, 5±3× 103 cells/cm2, respectively, indicating that the number of cells was directly proportional to the strength of the biofilm. The hydrophobicity index (HI) analysis revealed higher hydrophobicity with an increased biofilm formation. Fatty acid methyl esterase analysis revealed the amount of certain fatty acids such as iso-C15:0, anteiso-C15:0, and anteiso-C17:0 fatty acids correlated with the biofilm-forming capability of L. monocytogenes. This study showed that different strains of L. monocytogenes form biofilm of different intensities which did not completely correlate with their serotype; however, it correlated with the number of cells, hydrophobicity, and amount of certain fatty acids.

Biofilm production by Staphylococcus aureus, an important virulence factor was investigated employing phenotypic and genotypic methods. A total of 102 S. aureus isolates from bovine subclinical mastitis cases were included in the study. Maximum number of biofilm producing strains were detected by Congo red agar (CRA) method (48.03%) followed by tube method (36.27%). Tissue culture plate method (TCP) without and with destaining identified 19.60 and 29.41% of S. aureus as biofilm producers, respectively. A polymerase chain reaction for detection of intercellular adhesion genes, icaA and icaD, responsible for biofilm formation was standardized. Of the 102 S. aureus isolates investigated, 36 (35.29%) strains revealed presence of both the genes. Considering polymerase chain reaction as a standard test, CRA and TCP without destaining were the most sensitive and specific, respectively. PCR technique standardized for detection of the icaA and icaD genes is reliable for identifying biofilm producing potential of S. aureus which may help in rapid detection of biofilm-producer Staphylococci. This would allow the early application of control measures.

The present study was carried out to genotypically characterize Staphylococcus aureus (S. aureus) isolated from bovine mastitis cases. A total of 37 strains of S. aureus were isolated during processing of 552 milk samples from 140 cows. The S. aureus strains were characterized phenotypically, and were further characterized genotypically by polymerase chain reaction using oligonucleotide primers that amplified genes encoding coagulase (coa), clumping factor (clfA), thermonuclease (nuc), enterotoxin A (entA), and the gene segments encoding the immunoglobulin G binding region and the X region of protein A gene spa. All of the isolates yielded an amplicon with a size of approximately 1,042 bp of the clfA gene. The amplification of the polymorphic spa gene segment encoding the immunoglobulin G binding region was observed in 34 isolates and X-region binding was detected in 26 isolates. Amplification of the coa gene yielded three different products in 20, 10, and 7 isolates. The amplification of the thermonuclease gene, nuc, was observed in 36 out of 37 isolates. All of the samples were negative for the entA gene. The phenotypic and genotypic findings of the present strategies might provide an understanding of the distribution of the prevalent S. aureus clones among bovine mastitis isolates, and might aid in the development of steps to control S. aureus infections in dairy herds.

An experiment was conducted to study the protective role of polyherbal feed supplement (Growell) during induced mycotoxicosis in broilers. A total of 240 Vencobb broilers were divided at day old stage into eight equal groups. Group A served as control and was given plain feed, group B, D, F and H were given Growell at 0.35 g/kg of feed. Group C, D, G and H were given dietary aflatoxin B 1 at 0.2 ppm and groups E, F, G and H were given ochratoxin A at 0.2 ppm in feed to study effect of Growell on individual aflatoxicosis, ochratoxicosis and combined mycotoxicosis of broilers. The chicks were given their respective feeds from 1st day to 6th week of age and were vaccinated at 7th and 28th day of age with Lasota strain of Newcastle disease virus. There was no statistically significant effect of mycotoxins individually or in combination on body weight of broilers. However, body weights were highest in group B and lowest in co-mycotoxicated group G. Feed conversion ratio was best in group B followed by A, D, F, E, H and G. Significant improvement in haemoglobin values was observed in broilers due to feeding of Growell in ochratoxin and co-mycotoxicated groups. There was no significant effect of mycotoxin treatment on PCV, TEC and TLC of broilers. Due to single and combined mycotoxicosis, there was reduction in serum total protein, albumin, cholesterol and triglyceride and rise in alkaline phosphatase, creatinine and uric acid levels. Supplementation of diets with Growell reduced the alterations induced due to mycotoxins. There was a significant rise in per cent organ weight of liver and reduction of that of spleen, bursa of Fabricius and thymus of broilers fed mycotoxins. Protection from alteration in per cent organ weight of these organ by supplementation of Growell was recorded. The observed impaired immune response and histopathological changes in liver, kidney, spleen, bursa of Fabricius and thymus of broilers given mycotoxins were protected by supplementation of Growell.

Two Listeria-like isolates obtained from mangrove swamps in Goa, India were characterized using polyphasic combinations of phenotypic, chemotaxonomic and whole-genome sequence (WGS)-based approaches. The isolates presented as short, non-spore-forming, Gram-positive rods, that were non-motile, oxidase-negative, catalase-positive and exhibited α-haemolysis on 5 % sheep- and horse-blood agar plates. The 16S rRNA gene sequences exhibited 93.7-99.7 % nucleotide identity to other Listeria species and had less than 92 % nucleotide identity to species of closely related genera, indicating that the isolates are de facto members of the genus Listeria. Their overall fatty acid composition resembled that of other Listeria species, with quantitative differences in iso C15 : 0, anteiso C15 : 0, iso C16 : 0, C16 : 0, iso C17 : 0 and anteiso C17 : 0 fatty acid profiles. Phylogeny based on 406 core coding DNA sequences grouped these two isolates in a monophyletic clade within the genus Listeria. WGS-based average nucleotide identity and in silico DNA-DNA hybridization values were lower than the recommended cut-off values of 95 and 70 %, respectively, to the other Listeria species, indicating that they are founding members of a novel Listeria species. We suggest the name Listeriagoaensis sp. nov. be created and the type strain is ILCC801 (=KCTC 33909;=DSM 29886;=MCC 3285).

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BackgroundBrucellosis is a widespread zoonotic infection. This disease is endemic in many parts of Asia, including India. Brucellosis is a major cause of pyrexia of unknown origin (PUO). Persons exposed to infected animals or contaminated animal products are at high risk. Seropositivity among animal handlers, veterinarians and dairy workers has been documented in India. Thus, the present study was aimed to determine prevalence of brucellosis among PUO cases and occupationally exposed individuals.MethodsIn this study, serum samples (n=282) from cases of pyrexia of unknown origin (PUO) (n=243), and occupationally exposed individuals (n=39) were collected and tested for brucellosis by Rose Bengal plate test (RBPT), serum agglutination test (SAT), indirect ELISA, IgG and IgM ELISA. Blood culture for isolation of Brucella was performed for 10 serologically positive patients using BACTEC 9050 automated blood culture system. Biochemical tests and PCR techniques were used for confirmation of the isolates.ResultsOf the samples tested, 4.25%, 3.54%, 6.02% and 4.96% samples were positive by RBPT, SAT, indirect ELISA and IgG ELISA, respectively. None of the sample was positive for IgM ELISA. Of the 10 blood samples cultured bacteriologically, one Brucella isolate was recovered. The isolate was confirmed as Brucella abortus. Amplification of the bcsp31 and IS711 genes was also observed.ConclusionSeropositivity for brucellosis was observed among PUO cases, animal handlers and dairy workers in Goa, India. The serological tests showed variable results. One Brucella isolate was obtained by performing blood culture. Confirmation of the case was done rapidly using molecular tools. General awareness about clinical symptoms should be increased which will improve proper diagnosis within short time frame.