Fitness cost, gyrB mutation, and absence of phosphotransferase system fructose specific IIABC component in novobiocin-resistant Streptococcus iniae vaccine strain ISNO.

To understand the fitness cost of novobiocin-resistance in an attenuated Streptococcus iniae vaccine strain ISNO compared to its virulent parent strain ISET0901, cell proliferation rate of the two strains were compared to each other. Our results revealed that the cell proliferation rates of ISNO were significantly (P<0.05) smaller than that of ISET0901. To understand whether there was any mutation at the target site of novobiocin, DNA gyrase subunit B (gyrB) was sequenced from both strains. Sequencing results revealed a point mutation of AGA to AGC, resulting in a deduced amino acid substitution of R635S. To determine whether any unique DNA sequence was present in ISET0901 but absent in ISNO, PCR-select bacterial genome subtractive hybridization was performed. A phosphotransferase system fructose specific IIABC component sequence was confirmed to be present in ISET0901 but absent in ISNO. Using genomic DNAs from ten field-strains of S. iniae as templates, the phosphotransferase system fructose specific IIABC component sequence was found to be present in five highly virulent strains, but absent in five avirulent strains. Taken together, our results suggest that: (1) As fitness cost of novobicin resistance, ISNO had significantly smaller cell proliferation rate; (2) point mutation at target site gyrB resulting in R635S substitution was associated with novobiocin resistance in ISNO; and (3) phosphotransferase system fructose specific IIABC component was associated with virulence of S. iniae.

A quantitative analysis of the supply and demand of veterinary manpower in India: implications for policy decisions.

The objective of this study was to estimate and forecastthe supply and demand of veterinary manpower in India. Intake numbers of veterinary students and numbers of graduates and postgraduates were collected for the period 1997 to 2007. Based on the annual growth rate, the demand and supply for the years 2015 and 2020 were predicted. Between 1997 and 2002 the average annual number of veterinary graduates was 1,675. This increased to 1,707 between 2002 and 2007, with a marginal growth rate of 1.87%. With a growth rate of 1.87% in graduates, and 4.5% growth rate in the Indian livestock sector, the number of additional graduates required to fill the gap between supply and demand for the years 2015 and 2020 would be 1,710 and 2,364, respectively. The annual postgraduate requirement for education and research and development is 310. However, between 2002 and 2007 the average annual number of veterinary postgraduates was 995, with a growth rate of 5.3% when compared with the period between 1997 and 2002, indicating a more than three-fold surplus. With a 5.3% growth rate in postgraduates and 4.5% growth rate in the livestock sector, the surplus postgraduates available by 2015 and 2020 will be 1,027 and 1,316, respectively. The study revealed that India is training fewer veterinary graduates and more postgraduates than the system requires. Therefore, it is recommended that attention and resources be directed to the expansion of professional undergraduate veterinary education, while postgraduate veterinary education should be contained and consolidated.

Effect of caprine arthritis-encephalitis virus infection on expression of interleukin-16 in goats.

OBJECTIVE: To determine the effect of caprine arthritis-encephalitis virus (CAEV) infection on expression of interleukin-16 (IL-16). ANIMALS: 6 goats experimentally infected with CAEV and 6 age-matched healthy uninfected control goats. PROCEDURE: Peripheral blood mononuclear cells (PBMCs) and synovial membrane cells from infected and control goats cultured with or without phytohemagglutinin were analyzed for IL-16 mRNA by use of a reverse transcriptase-polymerase chain reaction assay with goat-specific primers, after cloning and sequencing of a 384-bp fragment of the goat IL-16 gene. Synovial fluid, serum, and culture supernatants of PBMCs and synovial cells of control and CAEV-infected goats were analyzed for IL-16 by use of an ELISA. RESULTS: The 384-bp product was 86% homologous to the corresponding human IL-16 nucleotide sequence. Higher expression of IL-16 mRNA in PBMCs (unstimulated or stimulated with phytohemagglutinin) was detected in samples from CAEV-infected goats, compared with control goats, but the difference was not significant. Synovial membrane cells infected in vitro had higher expression than uninfected control cells. Higher IL-16 concentration was detected in synovial fluid, serum, and culture supernatants of PBMCs of infected goats than in samples from control goats. CONCLUSIONS AND CLINICAL RELEVANCE: infection with CAEV increases expression of IL-16, a proinflammatory and chemotactic cytokine. This cytokine appears to be constitutively expressed at low concentrations in normal uninfected PBMCs and synovial membrane cells. Increased production of IL-16 in CAEV infection may partly be responsible for increased lymphoid cell infiltrations observed in arthritic joints and other tissues of CAEV-infected goats.

Detection of Listeria monocytogenes in pigs and pork.

In this study, we surveyed hogs (n = 300) as well as pork products (ground pork and raw chitterlings) for Listeria monocytogenes. Pig specimens collected before (tonsil swabs) and after slaughter (tonsils, lymph nodes, carcass swabs, and rectal contents) were examined for L. monocytogenes by enrichment with conventional enrichment broths followed by subculturing to selective agar. A multiplex polymerase chain reaction assay targeting the highly conserved 16S rRNA gene of the Listeria species as well as the hlyA gene unique to L. monocytogenes was used to screen aliquots of the enrichment (method I) as well as to confirm presumptive Listeria colonies from Columbia agar with 0.05% glucose supplemented with polymyxin B-acriflavine-lithium chloride-ceftazidime-aesculin-mannitol (PALCAM; method II). Subculturing to PALCAM agar was the more sensitive of the two methods on the basis of the overall detection of Listeria. For hog tissues, method I detected L. monocytogenes (0.87% positive) and no other Listeria spp. in all samples (n = 1,849). In contrast, method II detected significantly more (P < 0.05) L. monocytogenes (2.38%) and Listeria spp. (0.38%) in these tissues. For small intestines (n = 300 raw chitterlings), L. monocytogenes was identified in 8.3% of enrichments with University of Vermont modified Listeria enrichment broth; plating to PALCAM slightly improved recovery (9%). Overall, ground pork samples (n = 340) harbored L. monocytogenes (45% positive) and other Listeria species (1.5% positive), as determined by method I. Subculturing to PALCAM significantly (P < 0.05) improved the detection of L. monocytogenes (50.2%) but not that of other Listeria species (1.7%). L. monocytogenes isolates (n = 243) were assigned to serotype 1 (53.5%), serotype 4 (25%), and serotypes other than 1 and 4 (21.4%).