Sukumar Saha

Identification, Molecular Detection and Antibiogram Profile of Bacteria Isolated from California Mastitis Test Positive Milk Samples of Crossbred Cows of Satkhira District in Bangladesh

Present study was conducted for the isolation, identification, molecular detection and antibiotic sensitivity patterns of the bacteria present in the California Mastitis Test (CMT) positive milk samples of clinical and sub-clinical mastitic crossbred (Friesian cross and Sahiwal cross) cows of Satkhira district. A total number of 598 quarters milk samples from 150 cows were tested by CMT kit, among them 82 quarters from 52 cows were positive for CMT. The bacteria isolated from 52 CMT positive milk samples were coagulase positive Staphylococcus aureus 27 (49.09%) followed by Escherichia coli 15 (27.27%), coagulase negative Staphylococcus (CNS) spp. 10 (18.18%) and Bacillus spp. 3 (5.45%) respectively. In this present study only 13 (48.15%) positive Staphylococcus aureus were positive against nuc gene by PCR. All the isolates of E.coli were further confirmed by PCR with species specific 16srRNA PCR. None of the isolates of E.coli revealed positivity in PCR by stx1 and stx2 genes. All the coagulase positive Staphylococcus aureus isolates were found sensitive to 6 antibiotics and resistant to 5 antibiotics. The Coagulase negative Staphylococcus spp. was also sensitive to 7 antibiotics and acquired resistant properties against 3 antibiotics. Most E.coli isolates were found resistant against 9 antibiotics already possessed multidrug resistant properties and sensitive to only 3 antibiotics. Bacillus spp. isolated from milk samples was highly sensitive against 5 antibiotics compare to other antibiotics of the panel. Antibiogram profile of this study revealed that, all the isolated bacteria were sensitive to Ciprofloxacin only.

Molecular Detection of Brucella spp. from Milk of Seronegative Cows from Some Selected Area in Bangladesh

Brucellosis is endemic in Bangladesh both in humans and in animals. A number of reasons complicate the diagnosis, as bovine brucellosis can be diagnosed by various serological tests. But the tests have a limitation; when the organism remains intracellular, the disease goes into chronic stage and the antibody titres may decline. The present study was conducted for isolation and detection of Brucella spp. by polymerase chain reaction (PCR) from seronegative cows. A total of 360 dairy cows from three geographical regions were screened serologically by Rose Bengal Plate Test (RBPT) where 24 samples were serologically positive and the rest of the samples were serologically negative. Among the 24 seropositive individuals, 11 were culture positive and 6 were culture positive from serologically negative dairy cows. The overall seroprevalence of brucellosis in cattle was 6.6% and in disease condition a higher prevalence was recorded in abortion (28.07%) followed by infertility (13.33%). To confirm the Brucella spp. in seronegative dairy cattle, the isolates were extracted and PCR was conducted, which produced 905 bp amplicon size of 6 Brucella spp. from milk sample. So, for the detection or eradication of brucellosis, a bacteriological test and a PCR technique should be performed with the serological test of milk.

Comparative efficacy of BAU-fowl cholera and DLS-fowl cholera vaccines in indigenous chicken

The present study was conducted to determine the immune response induced in indigenous chicken produced against BAU-FC and DLS-FC vaccines with their efficacy study against Pasteurella multocida. A total of forty (40) chickens were selected and divided into Group A (15), Group B (15) and Group C (10). Group A and B were vaccinated with BAU-FCV and DLS-FCV, respectively at the dose rate of 0.5 ml through SC at six weeks of age followed by boostering at 10 weeks of age while Group C was kept as unvaccinated control. Sera samples were collected after primary and booster vaccination and antibody titre was determined by Passive hemagglutination (PHA) test. The mean PHA titres recorded at 4 weeks after primary vaccination was 51.20 ± 7.84 in birds of group A and 38.40 ± 6.40 in birds of Group B. After booster vaccination, mean PHA titer was found 140.80 ± 31.35 at 16 weeks of age in case of BAU-FC vaccinated group and 115.20 ± 12.80 in case of DLS-FC vaccinated group. The mean PHA titer was 204.80 ± 31.35 and 179.20 ± 31.35 at 19 weeks of age in birds of BAU-FC and DLS-FC vaccinated group, respectively. Birds of all groups were challenged with virulent P. multocida at 17 weeks of age. It was observed that vaccinated chickens showed maximal resistance (100%) following challenge with virulent whereas unvaccinated control birds failed to resist the challenge infection. It can be assumed from the findings of present research work that both BAU-FCV and DLS-FCV are able to protect indigenous chicken from the outbreak of avian pasteurellosis and BAU-FV vaccine showed relatively higher immuno-protective titre than that of DLS-FC vaccine. Res. Agric., Livest. Fish.5(2): 193-199, August 2018

STANDARDIZATION OF EFFECTIVE DOSE OF FOWL CHOLERA VACCINE IN PIGEON IN BANGLADESH

An experiment was conducted to determine the effective dose of formalin killed (FK) fowl cholera (FC) vaccines prepared with virulent avian Pasteurella multocida (PM 38) serotype 1 (X-73) collected from the laboratory of the Department of Microbiology and Hygiene, BAU, Mymensingh. To determine the effective dose of vaccine, 7 weeks old 30 pigeons were immunized and each group consists of 5 birds. The groups are represented by A, B, C, D, E and F. The birds belonging to groups (A-E) were vaccinated with different doses of vaccine, after two weeks of first, second immunization and challenge experiment, blood was collected from all vaccinated birds, and serum was analyzed to determine antibody titer against P. multocida by passive hemagglutination test (PHA). The PHA titer after two weeks of first vaccination were 16±3.92, 17.6±3.92, 25.6±3.92, 32±8.76, 35.2±7.84 of group A,B,C,D and E, respectively at the dose of 0.2ml (0.26×108 CFU)/birds, 0.4ml (0.5×108 CFU)/birds, 0.8 ml (1.04×108 CFU)/birds, 1ml (1.3×108 CFU)/birds, respectively. The PHA titer of prevaccination and control birds was <4. The PHA titer after 2 weeks of second vaccination or boostering were 32±8.76, 35.2±7.84, 44.8±7.84, 57.6±18.66, 70.4±15.68, of group A,B,C,D and E, respectively. After 2 weeks of challenge infection, the mean PHA titer were 44.8±7.84, 51.2±7.84, 70.4±15.68, 102.4±15.68 and 140.8±31.34 of group A,B,C,D and E, respectively. In this experiment, the antibody titer of the vaccinated pigeons with 0.4, 0.6, 0.8 and 1ml per bird via intramuscular route were higher than that of the pigeons vaccinated with 0.4ml/bird, 0.6ml/bird, 0.8ml/bird and 1ml/bird were satisfactory in terms of protective potential against P. multocida. For prevention and control of avian pasteurellosis 0.4ml to o.6ml (0.52×108 CFU to 0.78×108 CFU)/birds of vaccine may be used instead of 1ml (1.3×108 CFU)/birds for better immunization of pigeon against fowl cholera infection.

Molecular Detection, Biological Characterization and Evaluation of Protective Potentiality of a Velogenic Strain of Newcastle Disease Virus Isolate of Bangladesh

Aims: The aim of this study was to isolate and characterize Newcastle disease virus (NDV) from recent outbreaks in Bangladesh and protective potentiality evaluation of a velogenic NDV strain. Methodology: A total of 19 lung tissue samples were collected from dead layer chickens of clinically suspected Newcastle disease (ND) cases. Ten days old embryonated chicken eggs, dayOriginal Research Article Hossain et al.; BJI, 17(3): 1-9, 2017; Article no.BJI.31123 2 old chick and six-week-old sero-negative chickens were used for the isolation and pathotype determination of the virus. Hemagglutination (HA), hemagglutination inhibition (HI) tests using antiAPMV-1 polyclonal serum were used for primary identification and reverse transcription polymerase chain reaction (RT-PCR) was carried out for the confirmation of the isolated viruses by amplification of F gene of NDV using gene specific primers. Three, out of eleven isolates of NDV were subjected to pathotype determination by mean death time (MDT), intracerebral pathogenecity index (ICPI) and intravenous pathogenecity index (IVPI). One of the isolates of NDV of the year 2012 was selected as vaccine candidate to determine its immunogenicity. ND vaccine was prepared by inactivating virulent Newcastle disease virus (vNDV) with 0.1% formaldehyde and adjuvanted with 40% aluminium hydroxide gel. Results: Of the 19 samples total eleven isolates were initially identified as NDV by HA and HI tests and finally confirmed by RT-PCR. Results of MDT, ICPI and IVPI indices indicated that all the isolates of NDV of 2011 and 2012 were velogenic in nature. The inactivated vaccine produced satisfactory level of antibody titre at 72 days of post vaccination and revealed 100% protection during challenge experiment with 2 egg lethal dosage, ELD50/bird against both the velogenic strains of NDV. Conclusion: The frequent outbreaks of ND caused by vNDV in Bangladesh could easily be controlled by using inactivated vaccine prepared with velogenic strain of NDV.