Indian J. Comp. Microbiol. Immunol. Infect. Dis. Vol. 30, No. 1 (Jan. - June), 2009: 57-58 . IN VITROzyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA ANTIBIOTIC SENSITIVITY PATTERN OF BACTERIAL ISOLATES FROM CLINICAL CASES OF BOVINE MASTITIS IN AND AROUND BHUBANFSWAR S. Ranabijuli*, T.K. Palai, L.N. Sarangi, K.K. Sardar' and H.K. Panda zyxwvutsrqponmlkjihgfedcba Department of Microbiology - College of Veterinary Science & AH, OUAT, Bhubaneswar - 751 003 (Orissa) zyxwvutsrqponmlkjihgfedcbaZYX India stands at number one position in the world's milk production map with total milk production of 100.9 millions tones (Anonymous, 2008). Mastitis is an important cattle disease and continues to be the major obstacle in the upcoming dairy industry causing ^n annual economic loss of over Rs. 1940 crores to our country's dairy sector (Manickam, 1998). The economic losses in mastitis are due mainly to reduced milk production, poor quality of milk, excess cost of veterinary services and treatment (Sasidhar et al. 1998). As mastitis is a multi-factorial disease, hence indiscriminate and improper use of antimicrobial agents leads to failure in treatment and development of multi-drug resistant strain of microbes. A wide variety of microbes responsible for bovine mastitis and their pattern of drug resistance continues to change in a particular area depending on different epidemiological factors, is a major hurdle in the containment of the disease. With the above background, the present study was undertaken to study the in vitro sensitivity pattern and resistant profile of mastitis-causing isolates against various commonly used antibiotics. A total 108 milk samples were received by the Department of Microbiology, College of Veterinary Science and Animal Husbandry, OUAT, Bhubaneswar through Teaching Veterinary Clinical Complex from clinical and subclinical mastitis cases of various areas in and around Bhubaneswar during the period from 01.01.2008 to 16.07.2009 (1.5 years). All the samples screened by Modified California Mastitis Test (MCMT) test were found positive. The milk samples were processed for isolation of bacteriological organisms as per standard bacteriological methods (Cruickshank et al, 1975). The isolates were then identified based on their staining character, colony morphology, biochemical tests, sugar fermentation properties (Holt, 1994; Garrity et al., 2005). The in vitro antibiotic sensitivity pattern was studied by disc diffusions method (Bauer et al., 1966) using 14 number of antibiotic discs (M/s Hi-Media Pvt Ltd, Mumbai) such as levofloxacin (5 |ig/disc), enrofloxacin (5 ^lg /disc), penicillin-G (10 units/disc), streptomycin (10 |ig/disc), gentamicin (10 pg/ disc), oxytetracycline (30 pg/disc), chloramphenicol (30 |jg/disc), ceftriaxone (30 ^Jg/disc), cephotaxime (30 pg/disc), cephadroxil (30 ng/disc), amoxycillin (10 pg/disc), cloxacillin (30 pg/disc), ciprofloxacin (5 pg/disc), ofloxacin (5 pg/disc). Of the 108 samples processed, 5 were found to be sterile for any kind of bacteriological development. Sterility of milk *Corresponding Author: e.mail - dr.sidhu.vet@gmail.com 'Department of Pharmacology and Toxicology sample collected from mastitic cows for bacterial culture was also reported by other workers (Ramprabhu et al., 2004) which may attributed to use of intra mammary antibiotic infusions before collection of milk from the udder. The other 103 samples invariably showed presence of more than one isolate which is in : close agreement with Ghose et al. (2003), and the reason for the . presence of more than one isolate in each case may be mainly due to secondary invasion by opportunist bacteria as a result of lowered resistance of the udder (Radostits et al, 2005). Amongst the isolates. Staphylococcus aureus, E. coli, Pseudonwnas spp. Streptococcus agalactiae, Proteus spp., Corynebacterium spp. and Bacillus spp. were more or less common along with few samples positive for Listeria spp. and Klebsiella spp. Similar type of findings were also reported by Wani et al. (2002); Dutta etal. (2007) and Roychoudhary and Dutta (2009). In the present study. Staphylococcus aureus was found to be the major pathogenic organism for mastitis, which was in line with other workers (Ghose et al., 2003; Sahay et al., 2006). The present findings demonstrated that most of the cultures were showing high sensitivite to chloramphenicol, enrofloxacin, levofloxacin and gentamicin while resistant pattern is more evident for some classical antibiotics like pencillin-G cephadroxil, cloxacillin, oxytetracycline (Table 1). The sensitivity pattern for streptomycin, ceftriaxone, cephotaxime, amoxicillin and ciprofloxacin showed an alarming indication of increasing resistant among the bacterial organisms to these chemotherapeutic agents. The increased resistance to these chemotherapeutic agents can be attributed to injudicious use of antibiotics in the mastitis cases (Ghose et al., 2003) and sometimes delay in bacteriological examination of the suspected milks. While Ramprabhu et al. (2004) reported ceftriaxone (92.68%) to be most effective followed by ciprofloxacin (87.80%), gentamicin (87.80 %), and chloramphenicol (70.73%); Chhabra and Arora (2006) also recorded effectiveness of cloxacillin (80.95%), ampicillin (30.95 %), gentamicin (52.30%) in mastitis. Our study is in consonance with the above workers but ceftriaxone revealed to be effective only in 46.72%, streptomycin (39.25 %) and ciprofloxacin (45.79 %) cases. This may be endorsed to the frequent use of ceftriaxone, ciprofloxacin and streptomycin in mastitis cases with improper dose and duration of treatment in veterinary practice under field condition. The current study showed that newer drugs like levofloxacin (76.63%), enrofloxacin, (80.37%), chloramphenicol (81.30%) and 57