Double and quadruple deletion mutant of EHV-1 is highly attenuated and induces optimal immune response

Equid alphaherpesvirus 1 (EHV-1) infection causes significant health problems in equines. The EHV-1 infection leads to abortion storm in mares, respiratory disease and myeloencephalopathy. Despite the wide use of vaccines, the outbreaks of EHV-1 infections keep occurring globally, suggesting the need for the development of improved vaccines. Gene deletion attenuated mutant viruses could be a good candidate for the development of modified live vaccines. Here, we report the generation of mutant EHV-1 by deleting virulence (glycoprotein E & internal repeat 6; IR6) and immune evasive (pUL43 & pUL56) associated genes either individually or in combinations; and comprehensive evaluation of mutants through in vitro characterization followed by in vivo study in murine model to adjudge the attenuation of the virus and immune responses generated by mutants vis-à-vis wild type (wt) virus. The EHV-1 mutants with deletion of IR6 and gE genes (vToH-DMV) and four genes (i.e., gE, IR6, pUL43 and pUL56) (vToH-QMV) revealed a significant reduction in plaque size with minimal loss in replication efficiency in comparison to the wt virus. Further, in vivo studies showed virus attenuation adjudged through significant reduction in clinical signs, weight loss, gross and histopathological lesions in comparison to wt virus also revealed improved immune responses estimated through serum neutralization and flow cytometric analysis of CD4 + and CD8 + cell populations. Thus it can be concluded that EHV-1 mutants viz. vToH-DMV and vToH-QMV (novel combination) are promising vaccine candidates and qualify to be studied for adjudging the protective efficacy with wt virus challenge.

Tracking the phage trends: A comprehensive review of applications in therapy and food production

In the present scenario, the challenge of emerging antimicrobial resistance is affecting human health globally. The increasing incidences of multidrug-resistant infections have become harder to treat, causing high morbidity, and mortality, and are posing extensive financial loss. Limited discovery of new antibiotic molecules has further complicated the situation and has forced researchers to think and explore alternatives to antibiotics. This has led to the resurgence of the bacteriophages as an effective alternative as they have a proven history in the Eastern world where lytic bacteriophages have been used since their first implementation over a century ago. To help researchers and clinicians towards strengthening bacteriophages as a more effective, safe, and economical therapeutic alternative, the present review provides an elaborate narrative about the important aspects of bacteriophages. It abridges the prerequisite essential requirements of phage therapy, the role of phage biobank, and the details of immune responses reported while using bacteriophages in the clinical trials/compassionate grounds by examining the up-to-date case reports and their effects on the human gut microbiome. This review also discusses the potential of bacteriophages as a biocontrol agent against food-borne diseases in the food industry and aquaculture, in addition to clinical therapy. It finishes with a discussion of the major challenges, as well as phage therapy and phage-mediated biocontrols future prospects.

Pathological and immunological protection induced by inactivated reverse genetics-based H3N8 equine influenza vaccine candidate in murine model

Equine influenza (EI) is an important viral respiratory disease of equines caused by influenza A virus (IAV). The antigenic drift in IAVs necessitates regular updating and harmonization of vaccine strain with the circulating virus. The reverse genetics-based recombinant viruses could be easy instrument in generating vaccine against circulating virus in a quick and effective manner. Present study has been envisaged to evaluate the immunogenicity and protective efficacy of inactivated recombinant equine influenza virus (rgEIV) vaccine candidate having six segments from H1N1 virus (A/WSN/33/H1N1) and HA (hemaglutinin) and NA (neuraminidase) segments from H3N8 equine influenza virus [(A/eq/Jammu-Katra/06/08) of clade 2 of Florida sublineage] generated through reverse genetic engineering. BALB/c mice were immunized with inactivated rgEIV adjuvanted with aluminium hydroxide gel and challenged with H3N8 virus (A/eq/Jammu-Katra/06/08). The protective efficacy was evaluated through serology, cytokine profiling, clinical signs, gross and histopathological changes, immunohistochemistry and residual virus quantification. Immunizations induced robust humoral immune response as estimated through hemagglutination inhibition assay (HAI). The antibodies were isotyped and the predominant subclass was IgG1. The vaccine candidate produced mixed Th1 and Th2 responses through stimulation of IFN-γ, IL-2, IL-4 and IL-6 expression. Immunization protected mice against challenge as reflected through reduction in clinical signs and body weight loss, early recovery, mild pathological changes (gross and histopathological lesions) as evident through scoring of lesions, low residual virus in nasopharynx and lungs quantified through egg titration and quantitative reverse transcriptase PCR (qRT-PCR). The study demonstrates that inactivated recombinant EIV generated through reverse genetic approach provides equivalent protection to that observed with inactivated whole H3N8 EIV vaccine. Keywords: equine influenza; reverse genetics; vaccine; pathology; murine model.

Association of Myroides odoratimimus in immunocompromized piglets with post weaning multisystemic wasting syndrome

AIM

To study the association of opportunistic infection due to Myroides odoratimimus in piglets immunocompromised by porcine circovirus type 2 (PCV2) infection.

METHODS AND RESULTS

The clinical samples (n = 101) were analysed bacteriologically. The isolates were identified by their phenotypes and MALDI TOF-MS analysis as Myroides species. The phylogram constructed based on nucleotide sequences of the 16S rRNA gene showed identity (~99%) with the M. odoratimimus isolates. The minimum inhibitory concentration values for antibiotics revealed M. odoratimimus to be resistant against carbapenem, cephalosporins, aminoglycosides and fluoroquinolones. The presence of PCV2 in affected tissue samples was confirmed by amplification of the 565 bp region of ORF2 of the PCV2 genome. The topology of the phylogenetic tree grouped the PCV2 with cluster-2d.

CONCLUSIONS

PCV2 being immunosuppressive in nature might have impaired the immunity thereby increasing the susceptibility of immunocompromised piglets to opportunistic pathogens such as M. odoratimimus leading to disease severity and high mortality. The M. odoratimimus isolates were found to be multidrug resistant and evidenced for uncertain clinical relevance and hence could act as hidden source of public health hazard.

SIGNIFICANCE AND IMPACT OF THE STUDY

Myroides odoratimimus is a rarely reported human pathogen. We reported the incidence of infection due to seemingly rare isolates of M. odoratimimus causing an outbreak of pneumonia in piglets. This appears, to the best of authors' knowledge, to be the first outbreak due to Myroides recorded in animal clinical cases described in the literature.

Isolation and characterization of multidrug-resistant Leclercia species from animal clinical case

Leclercia adecarboxylata, a Gram-negative bacillus of family Enterobacteriaceae, is an uncommonly identified pathogen isolated from environmental and clinical specimens. Most of the human infections are polymicrobial and commonly occur in immunocompromised hosts, although nosocomial infections in immunocompetent hosts have been documented. Here, we describe the case of isolation of Leclercia species as polymicrobial infection from bovine suffering from respiratory distress in Chhattisgarh state of India. The isolates were identified by their phenotypes, 16S rDNA sequencing and MALDI-TOF-MS. The isolate was found to be resistant to aminoglycosides and fluoroquinolone antibiotics and intermediate resistant to cephalosporins and evidenced for uncertain clinical relevance and could act as hidden source of public health hazard.

SIGNIFICANCE AND IMPACT OF THE STUDY

Leclercia adecarboxylata is a rarely reported human pathogen. We report here the case from bovine suffering from respiratory distress; the sample yielded Leclercia species as polymicrobial culture. The isolate was found to be multidrug resistant and evidenced for uncertain clinical relevance and could act as hidden source of public health hazard. The limited literature available on this organism is reviewed, and the potential implications of findings are discussed. To the best of our knowledge, this is the first report of isolation and characterization of multidrug-resistant Leclercia species from animal clinical case from India.

Genetic Analysis of the Neuraminidase (NA) Gene of Equine Influenza Virus (H3N8) from Epizootic of 2008-2009 in India

The neuraminidase (NA) gene sequences of four Indian equine influenza viruses (EIVs) isolated from epizootic in 2008 and 2009 were analyzed. The phylogenetic relationship and selection pressure of NA genes were established in comparison to other EIVs circulating worldwide along with the domains and motifs of the encoded protein to find out the significance of mutational changes. Among Indian isolates, two amino acid (aa) changes each in Mysore/12/08 (Asn67Tyr & Asp396Gly), Gopeshwar/1/09 (Ile49Val & Asp396Gly), and Uttarkashi/1/09 (Ile49Val & Asp396Gly) isolates were observed in respect to Jammu-Katra/06/08 isolate. Amino acid (aa) sequence analysis also revealed five consistent aa residue changes viz, Gly/Arg40Glu, Tyr66His, Val191Ile, Val209Ile and Asp235Asn in Asian including Indian isolates, Spain/07 and Spain/09 isolates in comparison to other EIVs circulating worldwide. The topology of the phylogenetic tree revealed that the Indian, Chinese, Mongolian and Kazakhstan isolates together formed a subgroup with Yokohama/10 isolate. Spain/07 & Spain/09 isolates showed closest clustering with Asian isolates. This indicates that non-synonymous mutations in Asian isolates with temporal pattern originating from Spain/07, led to the subgroup of the Asian isolates within Florida clade 2 sublineage. The analysis of the predicted secondary structure has not shown any significant difference in the NA proteins of all Indian isolates. Fixed-effects likelihood (FEL) analysis of the selection pressure revealed three codons (43, 355 & 434) under positive selection pressure. The overall evolutionary changes (ω value) of 3.4 indicates NA gene to be under strong selection pressure. Further, seven putative N-glycosylation sites were observed in the NA protein. The mapping of specific aa changes, their mutational and functional analysis need to be carried out to ascertain their role in pathogenecity of the virus.

Molecular appraisal of Indian animal isolates of Echinococcus granulosus

BACKGROUND & OBJECTIVE

Cystic echinococcosis (CE) has a wide host range and distinct entities, not only reflected phenotypically but also by genotypic variation. Considering this fact, this study was undertaken to characterize the Indian isolates of Echinococcus granulosus to find out difference between Indian cattle, buffalo and sheep isolates on the basis of random amplification of polymorphic DNA (RAPD) PCR and PCR mediated restriction fragment length polymorphism (PCRRFLP) of internal transcribed spacer gene 1 (ITS1).

METHODS

A total of 22 isolates of E. granulosus obtained from Indian cattle, buffalo and sheep (December 2004 - November 2005) were analysed by 26 random primers of 8-10 mers. After isolation of protoscoleces from fertile cyst, DNA was extracted, quantified and amplified by random primers. Internal transcribed spacer gene 1 (ITS1) was amplified using specific primer and digested by two restriction enzymes (Msp1 and Rsa1).

RESULTS

Of the 26 primers, only two primers (5'ACC TGG ACA C3' and 5' TCA TCC GAG G3') could discriminate cattle, buffalo and sheep isolates collected from eastern part of India. Samples were further analysed by PCR mediated RFLP of internal transcribed spacer gene1 (ITS1) using two restriction enzymes (Msp1 and Rsa1). No ITS1 variants could be detected.

INTERPRETATION & CONCLUSION

Our findings showed genotypic variation among Indian animal isolates of E. granulosus on the basis of RAPD fingerprinting.

Cloning, sequencing and expression of cDNA of bovine neutrophil beta-defensin from water buffalo (Bubalus bubalis)

Neutrophil beta-defensins have been identified as naturally occurring potent antibacterial cationic peptides serving as effector molecules of innate immunity that provide a first line of defence against pathogens. Considering the broad-spectrum antimicrobial activity against microorganisms and role in innate immunity of the neutrophil beta-defensins, it has been characterized in many livestock species including cattle, sheep, caprine and porcines. Here we report the isolation, cloning, sequencing and expression of precursor bovine neutrophil beta-defensin isolated from Indian water buffalo. Full-length cDNA was amplified using reverse transcription polymerase chain reaction (RT-PCR). The cDNA contained an open reading frame of 192 bp encoding a putative polypeptide of 63 amino acids. Deduced amino acid sequence of buffalo BNBD4 showed varying amino acid identity with the published sequences of related beta-defensins of other domestic ruminant species ranging from 67.18 to 79.68%. Recombinant buffalo defensin was produced in Escherichia coli as fusion protein.

Genotypic characterisation of Indian cattle, buffalo and sheep isolates of Echinococcus granulosus

Twelve isolates of Echinococcus granulosus, collected from domestic animals, including cattle, buffalo and sheep were analysed for DNA nucleotide sequence variation within mitochondrial cytochrome c oxidase I (coxI), NADH dehydrogenase subunit I (nadI) and internal transcribed spacer gene I (ITS1). After analysis of sequence information this was found that the fragment size of ITS1 of buffalo isolate was more in comparison to cattle and sheep isolates. Based on the nadI genotype this was found that Indian cattle, buffalo and sheep isolates could be grouped into E. granulosus sensu stricto. Based on coxI genotype two sheep isolates and one buffalo isolate were homologous to G2 genotype. Rests of the isolates were microvariants of G2 genotype. Presence of G2 genotype in buffalo is the first report of this genotype from this host.

Cloning and sequencing of Indian water buffalo interleukin-18 cDNA

Summary Full-length cDNA (582 bp) of the interleukin-18 (IL-18) gene of the Indian water buffalo (Bubalus bubalis) was amplified by reverse transcriptase-polymerase chain reaction (RT-PCR) and sequenced. The deduced amino acid sequence has 99% and 95% similarity with the IL-18 sequences of cattle and sheep, respectively. There are two amino acid substitutions at positions 132 and 182 in buffalo IL-18 compared with that of cattle. Phylogenetic analysis showed that the IL-18 sequence of fish forms a different lineage and is most divergent from that of cattle, buffalo, sheep, pig, dog, horse, human, monkey, mouse, rat and chicken.