Samiran Bandyopadhyay

Bovine herpesvirus-1 (BHV-1) – a re-emerging concern in livestock: a revisit to its biology, epidemiology, diagnosis, and prophylaxis

Bovine herpesvirus-1 (BHV-1) is known to cause several diseases worldwide. It is a double-stranded DNA virus consisting of 33 structural proteins out of which 13 are associated with the envelope. Based on genomic analysis and viral peptide patterns, BHV-1 virus can be divided into several subtypes like BHV-1.1, BHV-1.2, and BHV-1.3. However, all subtypes are antigenically similar. The symptoms of the related diseases are mainly non-life-threatening but have a rather wide host range that limits animal trade. The different modes of transmission as unique feature of this virus and the tendency to cause infection in the early age with latency development in trigeminal and sacral ganglion cause huge economic losses around the world. The virus also affects endangered bovine species like mithun (Bos frontalis) and yak (Poephagus grunniens). The disease can be diagnosed by using conventional procedures (like cell culture, immune-histopathology, and enzyme-linked immunosorbent assay (ELISA)) as well as highly sensitive modern techniques (like nested PCR and southern hybridization) with the virus neutralization test regarded as gold standard. With the currently available diagnostic tests it is not possible to identify animals which have a latent BHV-1 infection. Different types of modern and conventional vaccines are available for immunoprophylaxis. Inactivated vaccines are not as efficacious as modified live virus (MLV) vaccines. Marker vaccines allow the distinction between vaccinated and naturally infected animals. In this review the present status of BHV-1 around the world will be addressed besides the current knowledge with regard to its biology, epidemiology, diagnosis, and prophylaxis.

Potential antibacterial activity of berberine against multi drug resistant enterovirulent Escherichia coli isolated from yaks (Poephagus grunniens) with haemorrhagic diarrhoea

OBJECTIVE To evaluate the antimicrobial efficacy of berberine, a plant alkaloid. METHODS Five multi-drug resistant (MDR) STEC/EPEC and five MDR ETEC isolates from yaks with haemorrhagic diarrhoea were selected for the study. Antibacterial activity of berberine was evaluated by broth dilution and disc diffusion methods. The binding kinetics of berberine to DNA and protein was also enumerated. RESULTS For both categories of enterovirulent Escherichia coli (E. coli) isolates, berberine displayed the antibacterial effect in a dose dependent manner. The MIC(50) of berberine chloride for STEC/EPEC isolates varied from 2.07 μM to 3.6 μM with a mean of (2.95 ± 0.33) μM where as for ETEC strains it varied from 1.75 to 1.96 μM with a mean of (1.87 ± 0.03) μM. Berberine bind more tightly with double helix DNA with Bmax and Kd of (24.68±2.62) and (357.8±57.8), respectively. Berberine reacted with protein in comparatively loose manner with Bmax and Kd of (18.9±3.83) and (286.2±113.6), respectively. CONCLUSIONS The results indicate clearly that berberine may serve as a good antibacterial against multi drug resistant E. coli.

Molecular and phylogenetic characterization of multidrug resistant extended spectrum beta-lactamase producing Escherichia coli isolated from poultry and cattle in Odisha, India.

The present study was undertaken to determine the occurrence and characterization of extended spectrum beta-lactamase (ESBL) producing Escherichia coli isolated from cattle and poultry in Odisha, India. Of 316 E. coli isolated from 305 samples (170 fecal samples from poultry and 135 milk samples from cattle), a total of 18 E. coli isolates were confirmed as ESBL producers by combination disc method and ESBL E-test. The isolates were resistant to oxyimino cephalosporins and monobactam as revealed by disc diffusion assay and determination of minimum inhibitory concentration. Resistance against other antibiotics was frequently noted as well. Further, beta-lactamase genes viz., blaSHV, blaCTXM, blaTEM and blaampC were detected in 17, 13, 9 and 2 isolates, respectively in PCR. Of the 18 ESBL strains, 16 were positive for class I integron (int1), nine of them carried sulphonamide resistance gene (sul1) and one harbored quinolone resistance gene (qnrB). Virulence markers for extraintestinal pathogenic E. coli like astA, tsh and iucD were also present in 4, 3 and 3 isolates, respectively. All the PCR amplified products were cloned and subjected to sequencing for homology analysis and data were submitted to gene bank. Sequence analysis of the amplified variable regions of class 1 integron of four representative isolates revealed the presence of aadA2 and dfrA12 gene cassettes conferring resistance to aminoglycosides and trimethoprim, respectively. Most of the ESBL producing strains emerged as single lineage through phylogenetic analysis by RAPD and ERIC PCR. This is the first ever systemic study on multidrug resistant ESBL producing E. coli in food producing animals from India.

Understanding osteomyelitis and its treatment through local drug delivery system

Chronic osteomyelitis is a major challenge in bone surgery. Conventional use of antibiotics is not an effective way to control the malaise due to so many reasons. Determination of optimal treatment strategy becomes difficult for the orthopaedic surgeons and as a consequence, the patients suffer not only from therapeutic failure but also due to adverse side effects of antibiotics and financial loss due to additional stay at hospitals. A wide application of carrier systems, as a medium for local delivery of antibiotics, is being used experimentally and clinically for the treatment of osteomyelitis. This kind of delivery system provides sustained higher concentration of antibiotics at the infection site with reduced possibility of toxicity. This review highlight etiology and pathophysiology of osteomyelitis, current therapeutic options with their limitations, and potentiality of biomaterial based carrier materials impregnated with antibiotics as local delivery approach.

Quantitative imaging of arsenic and its species in goat following long term oral exposure

Severity of arsenic toxicity was reported to vary depending on its species. The present study reflects the status of different species of arsenic in goat following long-term exposure of arsenic leading to hepatic damage. The experiment was conducted with six black Bengal goats, which were administered with sodium arsenite orally at a dose rate of 2 mgkg(-1) daily for 84 days. Faeces, urine, hair and blood samples were collected from those animals at 14 days interval. Excretion of total arsenic was reduced from 56 days onwards through both faeces and urine indicating higher accumulation of arsenic in body. The speciation study revealed that urinary arsenic was mainly of organic type, whereas hair accumulated almost equal proportion of arsenite, arsenate and organo arsenicals. Goats excreted high proportion of organo arsenicals through faeces possibly due to hepatobiliary secretion of organo arsenic into the gut. Significantly elevated serum alanine aminotransferase and aspartate aminotransferase activities (p<0.05) along with histopathological changes in liver indicated hepatotoxicity. The arsenite fraction increased and organic proportion decreased in urine as the time progressed, which indicates that arsenite gets methylated in liver of goat. The study thus alluded that the toxicity of arsenic would aggravate if the animals were exposed for long time as the hepatotoxicity progressed resulting in decreased methylation and formation of organo arsenicals and decreased excretions through urine.

Pleurotus florida lectin normalizes duration dependent hepatic oxidative stress responses caused by arsenic in rat

Natural contamination of arsenic in ground water is a major health problem throughout the World. It is one of the most hazardous substances in the environment known to cause toxicity in multiple organs via oxidative stress. The molecular basis for arsenic toxicity involves direct or indirect damage to protein, lipid and DNA. Various studies have focused on the possible toxic effects of arsenic on membrane components and its correlation with oxidative damage. The present study was aimed to mitigation of arsenic induced hepatic oxidative stress by dietary modulation using of mushroom lectin in rats. Animals were divided into four groups; the first group was used as control. Groups 2, 3 and 4 were arsenic (20 ppm) exposed through drinking water, arsenic exposed plus oral ascorbic acid (25 mg/kg body weight) and arsenic exposed plus oral mushroom lectin (150 mg/kg body weight) respectively for a period of 12 weeks. We observed significant alterations in the antioxidant enzymes, oxidative stress intermediates and SOD(2) gene expression profile on arsenic exposure. These alterations were restored by co-administration of Pleurotus florida lectin which was as potent as standard antioxidant viz. ascorbic acid. The findings of the experiment suggested that P. florida lectin has capability of modulating arsenic mediated toxic effects and could be helpful in ameliorating them.

Virulence Repertoire, Characterization, and Antibiotic Resistance Pattern Analysis of Escherichia coli Isolated from Backyard Layers and Their Environment in India

SUMMARY This study was undertaken to observe the prevalence, serogroup, avian pathogenic Escherichia coli (APEC)-associated virulence gene, randomly amplified polymorphic DNA (RAPD) pattern, and antibiotic resistance genes of E. coli in backyard layers and their environment in India. From the 360 samples of healthy layers and their environment, 272 (75.5%) E. coli were isolated. The majority (28.67%) of them were untypeable. Among the studied virulence genes (papC, tsh, iucC, astA), 52 (14.32%) isolates were found to possess astA, including the isolates from the drinking water of the birds (4/272, 1.47%). These strains belonged to 18 different serogroups. Most of the isolates were typeable by RAPD and they produced different patterns. Phenotypic resistance of the isolates was most frequently observed to erythromycin (95.83%), chloramphenicol (87.52%), and cotrimoxazole (78.26%). None of the isolates was found to possess extended-spectrum beta-lactamases (blaTEM, blaSHV, blaCTX-M) or quinolone resistance (qnrA) genes by PCR. The present study was the first attempt in India to assess APEC distribution in backyard poultry production. RESUMEN Repertorio de virulencia, caracterización y análisis de los patrones de resistencia a los antibióticos de Escherichia coli aisladas de gallinas de postura de traspatio y de su medio ambiente en la India. Este estudio se realizó para determinar la prevalencia, el serogrupo, los genes asociados a virulencia de Escherichia coli patógena para las aves (APEC), los patrones de ADN polimórfico amplificado aleatoriamente (RAPD), y los genes de resistencia a los antibióticos de E. coli en gallinas de traspatio y su ambiente en la India. De las 360 muestras de gallinas sanas y de su ambiente, se aislaron 272 cepas de E. coli (75.5%). La mayoría (28.67%) de ellas no fueron tipificables. Entre los genes de virulencia estudiados (papC, tsh, iucC, astA), se encontró que 52 aislamientos (14.32%) poseían el gene astA, incluyendo los aislamientos de agua de bebida de las aves (4/272, 1.47%). Estas cepas pertenecían a 18 serogrupos diferentes. La mayoría de los aislamientos fueron tipificables mediante RAPD y produjeron diferentes patrones. La resistencia fenotípica de los aislamientos se observó con mayor frecuencia contra eritromicina (95.83%), cloranfenicol (87.52%), y contra cotrimoxazol (78.26%). Se encontró mediante PCR que ninguno de los aislamientos poseía genes de un espectro extendido de beta-lactamasas (blaTEM, blaSHV, blaCTX-M), o resistencia contra quinolonas (qnrA). El presente estudio es el primer intento en la India para evaluar la distribución de E. coli patógena para la producción de aves de traspatio.

Extended-Spectrum-β-Lactamase-Producing Escherichia coli Isolate Possessing the Shiga Toxin Gene (stx1) Belonging to the O64 Serogroup Associated with Human Disease in India

Shiga toxin-producing Escherichia coli (STEC) causes a spectrum of human sufferings, like bloody diarrhea and even life-threatening conditions, such as hemolytic uremic syndrome (HUS) ([1][1]). In addition to the serotype O157:H7, several serogroups of STEC have been isolated from severe outbreaks

Co-infection of methicillin-resistant Staphylococcus epidermidis, methicillin-resistant Staphylococcus aureus and extended spectrum β-lactamase producing Escherichia coli in bovine mastitis – three cases reported from India

Emergence of antimicrobial resistance among bovine mastitis pathogens is the major cause of frequent therapeutic failure and a cause of concern for veterinary practitioners. This study describes intra-mammary infection of methicillin-resistant Staphylococcus epidermidis (MRSE), methicillin-resistant Staphylococcus aureus (MRSA) and extended spectrum β-lactamase (ESBL) producing Escherichia coli in two Holstein Friesian crossbred cows with subclinical mastitis and one non-descript cow with clinical mastitis in two different districts of West Bengal, India. In total, three MRSE, one MRSA and three ESBL producing E. coli were isolated from these cases. Both the crossbreds were detected with MRSE (HFSE1 and HFSE2) and ESBL producing E. coli (HFEC1 and HFEC2), whereas, simultaneous infection of three pathogens viz. MRSA (NDSA1), MRSE (NDSE1) and ESBL producing E. coli (NDEC1) was found in the non-descript cow. The methicillin-resistant isolates possessed mecA gene and exhibited resistance to various antibiotics such as amikacin, tetracycline and glycopeptides. The ESBL producers were positive for blaCTX-M and blaTEM genes; in addition, HFEC1 and HFEC2 were positive for blaSHV and possessed the genes for class I integron (int1), sulphonamide resistance (sul1), quinolone resistance (qnrS) and other virulence factors (papC, iucD and ESTA1). All the ESBL producers exhibited resistance to a variety of antibiotics tested including third- and fourth-generation cephalosporins and were also intermediately resistant to carbapenems. This is the first ever report on simultaneous occurrence of MRSE, MRSA and ESBL producing E. coli in bovine mastitis indicating a major concern for dairy industry and public health as well.

Approaches to characterize extended spectrum beta-lactamase/beta-lactamase producing Escherichia coli in healthy organized vis-a-vis backyard farmed pigs in India

The study was undertaken to investigate the occurrence and to characterize the ESBL/beta-lactamase producing-Escherichia coli in healthy pigs of organized and backyard farms in West Bengal, India. Total 200 rectal swabs were collected randomly from healthy pigs maintained in four organized farms and 10 backyard farms (n=100 each) and 76 isolates were identified as E. coli from organized (48/100, 48%) and backyard pigs (28/100, 28%). Twelve E. coli isolates (6%) in the present study were detected to possess any of the ESBL/beta-lactamase genes studied. ESBL/beta-lactamase producers were isolated with significantly more frequency from backyard pigs than the organized farm pigs (p=0.026). Six of ESBL/beta-lactamase producing isolates were phenotypically confirmed as CTX-M producers and ten of them were confirmed as TEM/SHV producers. PCR and sequencing of the amplified product from representative isolates revealed the presence of blaCTX-M-9, blaSHV-12 and blaTEM-1. No unique combination of the studied beta lactamase genes for organized and backyard farm pig isolates was noted. The ESBL isolates belonged to O13, O55, O133, O153, O157, O158, O166, rough and OUT serogroups. The association of heat labile toxin (elt) (p<0.0005) with organized farm isolates and heat stable toxin (estA) (p=0.0143) with backyard piggery sector was significantly higher. The ESBL/beta-lactamase producers from organized farm (Ak/Ex) and indigenous pigs (Ak/Ex/Te; Ak/CoT/G) showed a characteristic phenotypical antibiotic resistance pattern. Two pairs of isolates from organized and backyard farm pigs showed clonal relationship indicating a possible transmission between the farms which were situated adjacently. Thus the present study revealed backyard farm pigs as major source of ESBL/beta-lactamase producing-E. coli associated with STa and characteristic antibiotic resistance pattern in India.