Physiological properties of indigenous lytic bacteriophages as monophage suspension and cocktail against poultry-adapted typhoidal Salmonella variants.

The emergence and spread of multidrug resistance among pathogens of the agro-food sector is increasing at an alarming rate, which has directed attention to the search for alternative to antibiotic therapy. The present work studied the physiological and population dynamics of lytic bacteriophages against avian-adapted Salmonella. Out of 28 positive samples, four bacteriophage isolates (SalØ-ABF37, SalØ-RCMPF12, SalØ-MCOH26, SalØ-DNLS42) were selected based on their ability to clearly lyse bacterial test strains. The isolates propagated were active against closely related D1 serotypes, i.e., S. Enteritidis and S. Typhimurium, with no heterologous activity against Escherichia coli ATCC 25922 and Staphylococcus aureus ATCC 23235. Each of the monophage suspension and cocktail efficiently suppressed the bacterial count from exponential increase in comparison to the untreated bacterial control. The bacterial turbidity was recorded as 0.244 at λ600 during 400 min of co-incubation, in contrast to bacterial control showing λ600 = 0.669. The latent period was recorded to be 25, 35, 25 and 30 for SalØ-ABF37, SalØ-RCMPF12, SalØ-MCOH26 and SalØ-DNLS42, with 73.00, 97.00, 132 and 75.00 PFU cell-1, respectively. The highest lytic activity was seen at 37.00 ˚C - 42.00 ˚C, with phage particle count being fairly stable at pH 3.00 - 9.00. Each of the isolates possessed dsDNA by being resistant to RNase A. The current study concludes that lytic phages are promising alternative to combat multidrug resistant superbugs. The physiological characterization and bacterial growth inhibition are important parameters in standardization of phage therapy.

Seroprevalence and risk factors of avian influenza H9 virus among poultry professionals in Rawalpindi, Pakistan.

BACKGROUND: Avian influenza H9 is endemic in commercial and backyard poultry in Pakistan and is a serious occupational health hazard to industry workers. This study aimed to determine the seroprevalence of avian influenza H9 infection in people working with poultry in Rawalpindi, Pakistan and assess the measures they took to protect themselves from infection. METHODS: A cross-sectional study was conducted from December 2016 to May 2017 of 419 people working with poultry in Rawalpindi Division, including farm workers, vaccinators, field veterinarians, butchers and staff working in diagnostic laboratories. Potential participants were randomly approached and gave written consent to participate. Data were collected using a standardized questionnaire and serum samples were processed to detect H9 antibodies using the haemagglutination inhibition test. RESULTS: Of the 419 participants, 406 (96.9%) were male. The mean age of the participants was 36.4 (SD 10.86) years. A total of 332 participants agreed to a blood test, 167 of whom were positive for A(H9) antibodies, giving an overall seroprevalence of 50.3%. Laboratory staff had the highest seroprevalence (100%) and veterinarians the lowest (38.5%). Vaccinators, butchers and farm workers had a seroprevalence of 83.3%, 52.4% and 45.5% respectively. Personals who used facemasks had significantly lower (P<0.002) seroprevalence (29.6%) than those who never used them (90.6%). Similarly, those who always used gloves and washed their hands with soap had a seroprevalence of 32.8% compared with 89.0% in those who never took these precautions. Of the participants who handled antigens, 92.3% were seropositive. CONCLUSION: Laboratory staff and vaccinators are exposed to viral cultures and influenza vaccines respectively which may explain their high seroprevalence.

Genomic Characterization of Antibiotic Resistant Escherichia coli Isolated From Domestic Chickens in Pakistan.

Poultry husbandry is important for the economic health of Pakistan, but the Pakistani poultry industry is negatively impacted by infections from Escherichia coli. We performed Illumina whole genome sequencing on 92 E. coli isolates obtained from the livers of deceased chickens originating in five Pakistani geographical regions. Our analysis indicates that the isolates are predominantly from the B1 and A clade and harbor a diverse number of antibiotic resistance and virulence genes, with no linkage between phylogeny and antibiotic resistance gene presence but some association between phylogeny and virulence gene and SNP presence for the B1 and E phylogroups. The colistin resistance gene mcr-1 and the quinolone resistance gene qnrS1 were both found in 13/92 isolates. Alarmingly, 82/92 of the E. coli strains characterized in this study are multidrug resistant with 100% (92/92) resistance to lincomycin, 81.5% (75/92) to streptomycin, 79.3% (73/92) to ampicillin and 66.3% (61/92) to ciprofloxacin. These results provide a high-resolution analysis of poultry-associated E. coli isolates in an area with a high endemic burden of antibiotic resistance. Surveillance of antibiotic resistance in poultry associated E. coli isolates is an important pillar of the One Health concept to integrate analysis of potential pathogens in human, animal, and environmental niches.

Sequence and phylogenetic analysis of virulent Newcastle disease virus isolates from Pakistan during 2009-2013 reveals circulation of new sub genotype.

Despite observing the standard bio-security measures at commercial poultry farms and extensive use of Newcastle disease vaccines, a new genotype VII-f of Newcastle disease virus (NDV) got introduced in Pakistan during 2011. In this regard 300 ND outbreaks recorded so far have resulted into huge losses of approximately USD 200 million during 2011-2013. A total of 33 NDV isolates recovered during 2009-2013 throughout Pakistan were characterized biologically and phylogenetically. The phylogenetic analysis revealed a new velogenic sub genotype VII-f circulating in commercial and domestic poultry along with the earlier reported sub genotype VII-b. Partial sequencing of Fusion gene revealed two types of cleavage site motifs; lentogenic (112)GRQGRL(117) and velogenic (112)RRQKRF(117) along with some point mutations indicative of genetic diversity. We report here a new sub genotype of virulent NDV circulating in commercial and backyard poultry in Pakistan and provide evidence for the possible genetic diversity which may be causing new NDV out breaks.

H7 avian influenza virus vaccines protect chickens against challenge with antigenically diverse isolates.

Vaccination has been a critical tool in the control of some avian influenza viruses (AIV) and has been used routinely in Pakistan to help control sporadic outbreaks of highly pathogenic (HP) H7 AIV since 1995. During that time, several AIV isolates were utilized as inactivated vaccines with varying degrees of success. In order to evaluate which H7 AIV strains may serve as optimal vaccines for diverse H7 AIVs from Pakistan we conducted vaccination-challenge studies with five H7 vaccines against challenge with two HPAIVs: A/chicken/Murree/NARC-1/1995 H7N3 and A/chicken/Karachi/SPVC-4/2004 H7N3. To further characterize the isolates antigenic cartography was used to visually demonstrate the antigenic relationships among the isolates. All vaccines provided similar protection against mortality, morbidity and shedding of challenge virus from the respiratory tract. However, some minor (not statistically significant) differences were observed and correlated with antibody levels induced by the vaccine prior to challenge.