Abstract—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. Keywords—CMT, PCR, nuc gene, stx1, stx2, Antibiogram. Manuscript received January 24, 2014. This work was supported in part by the Department of Microbiology and Hygiene, Bangladesh Agricultural University and Bangladesh Agricultural Research Council. Md. Ehsanul Haque is with the FnF Pharmaceuticals Ltd. in Bangladesh as a Microbiologist, (E-mail: faysalvet@yahoo.com). Mohammed Alimul Islam is now with the Department of Microbiology and Hygiene, Bangladesh Agricultural University, Mymensingh as a Professor, (E-mail: alim_bau@yahoo.co.in). Sharmin Akter is with the FnF Pharmaceuticals Ltd. in Bangladesh as a Microbiologist, (E-mail: sharminrumi1@yahoo.com). Sukumar Saha is now with the Department of Microbiology and Hygiene, Bangladesh Agricultural University, Mymensingh as a Professor. (Mobile: +88017140847339; Fax: +88-091-55810; E-mail: sukumar94@yahoo.com). I. INTRODUCTION Bangladesh has a good number of both the pure and cross- bred cattle population (21.5 million) with about 3.33 million of dairy cows [1]. Around 20,582 mini dairy farms each with five or more high yielding cross-bred cows have been established in private sector in Bangladesh [2] and most of these dairy farms are confronted with problems of clinical and sub-clinical mastitis [3]. The clinical mastitis can be diagnosed on the basis of history and clinical findings but laboratory examinations are required to ascertain the sub- clinical mastitis. It is now a well known fact that the Sub clinical Mastitis (SCM) is more serious and is responsible for greater loss to the dairy industry in Bangladesh and the annual economic losses incurred due to reduced milk production alone by SCM in Bangladesh have been estimated to Taka 122.6 million (US $ 2.11million) [4]. Besides causing huge economic losses of milk production, the SCM remain as a continuous source of infection to other herd mates. If the infection persists for longer periods, then it may form a fibrous tissue barrier between the organisms and the antibiotics therapy, thus, limiting their efficacy. It is, therefore, important to know the prevalence of SCM in dairy herds and delineate the important factors responsible for it. The SCM can be known only after laboratory examination, as there are no gross inflammatory changes in the udder tissue. The mastitis causing organism, Staphylococci, the chief udder pathogen, has been isolated from almost all the body site examined and environment but Streptococci from fewer body sites, whereas the prevalence of Escherichia coli has been reported to be widespread [5], [6]. The indiscriminate use of antibiotics for the treatment of bacterial mastitis makes the udder more susceptible for the development of resistant bacteria. It is therefore also important to study the sensitivity pattern of different bacteria isolated time to time from mastitic cows in different geographical zones of the country in order to formulae appropriate therapeutic measures with suitable antibiotics. Considering the above facts, this research work was undertaken with the objectives of isolation and identification of important bacterial population from CMT positive milk Identification, Molecular Detection and Antibiogram Profile of Bacteria Isolated from California Mastitis Test Positive Milk Samples of Crossbred Cows of Satkhira District in Bangladesh Md. Ehsanul Haque, Mohammed Alimul Islam, Sharmin Akter and Sukumar Saha, Department of Microbiology and Hygiene, Bangladesh Agricultural University, Mymensingh DOI: 10.5176/0000-0003_1.1.8 GSTF International Journal of Veterinary Science (JVet) Vol.1 No.1, March 2014 59 © 2014 GSTF brought to you by CORE View metadata, citation and similar papers at core.ac.uk provided by GSTF Digital Library (GSTF-DL): Open Journal Systems (Global Science and Technology...