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Background: Cephalosporins are major antimicrobials used to treat serious infections. However, their effectiveness is being compromised by the emergence of extended spectrum beta lactamases (ESBL). The present study was aimed to characterize ESBL producing Escherichia coli from healthy and diarrheic cattle calves. Methods: A total of 52 rectal swabs were collected from healthy and diarrheic cattle calves between August 2019 to March 2020. Phenotypically E. coli were characterized based on morphology, microscopy and biochemical tests. Extended Spectrum Beta Lactamases (ESBL) E. coli initial screening was performed by using cefpodoxime, ceftazidime, cefepime and aztreonam antibiotics. The confirmation of the ESBL producing strains was conducted through ESBL phenotypic identification kit and double disc diffusion test (DDDT). Molecular characterization of ESBL E. coli was conducted by PCR amplification of blaCTX-M, bla TEM and bla AmpC genes. Plasmid profiling of the ESBL E. coli isolates was carried out. Result: Phenotypically, out of the 51 E. coli isolated, 05 (9.8%) E. coli isolates were confirmed as ESBL strains. PCR amplification revealed 01 (20%), 04 (80%) and 03 (60%) isolates positive for blaCTX-M, bla TEM and bla AmpC genes, respectively. Plasmid profiling of the isolates showed that 60% isolates were harboring plasmids of varying size and number. The plasmid number among the isolates ranged from 0-4 plasmids per isolate and plasmid size varied from 900bp to greater than 10kb. The relatively high rates of ESBL producers in diarrheic calves were found than healthy calves. The study highlights the existence of ESBL producing E. coli isolates with certain strains carrying mobile genetic elements in livestock and probable disseminators of resistance, thus imposing public health threat.

Background: The present study was aimed at cloning and expression of the major outer membrane porin (ompH) gene of P. multocida serotype B:2 P52, the strain used in vaccines against HS in India. The Porin H (OmpH) is major immunodominant outer membrane protein in the envelope of Pasteurella multocida. Methods: The gene encoding OmpH was amplified by PCR, cloned and expressed in prokaryotic expression vector. The recombinant OmpH protein was expressed as a protein with E. coli BL21 (DE3) cells transformed with recombinant plasmid pQE30-Xa-ompH. Result: The expressed protein was purified from E. coli and characterized by SDS-PAGE and western blot analysis. The fusion recombinant protein eluted had a molecular mass of about 34 kDa. The expressed recombinant protein was confirmed with western blot analysis using RGS-His antibody and anti-P. multocida serum raised against whole cell lysate.

Background: Mastitis is mostly caused by mixed infections, of which S. aureus and E. coli are amongst the most important bacteria. Detection of resistant strains of these bacteria is a major public health concern due to the possibility of infection via contaminated milk and milk products intended for human consumption. This study describes simultaneous occurance of methicillin-resistant S. aureus and extended spectrum β-lactamase producing E. coli in mastitic milk samples of buffaloes in Jabalpur, India. Methods: A total of 408 buffaloes milk samples were screened for mastitis by California mastitis test (CMT) test. A total of 102 mastitic milk samples were collected for isolation of Staphylococcus aureus (S. aureus) and Eschirichia coli (E. coli). Polymerase chain reaction was performed for molecular characterization of methicillin resistant S. aureus for mecA gene and ESBL producing E. coli for bla TEM gene, respectively. Result: On the basis of cultural and biochemical characteristics, 31/102 samples yielded S. aureus and 10/102 samples yielded E. coli. Out of 31 S. aureus isolates, mecA gene was positive in 05 (16.1%) and out of 10 ESBL producing E. coli isolates bla TEM was positive in 02 (20%) isolates. Coexpression of bla TEM and mecA genes was recorded only in 01 (10%) isolate.