doi:10.5455/vetworld.2013.354-356 Antibiogram of mastitis pathogens in the milk of crossbred cows in Namakkal district, Tamil Nadu

Aim: The present study was undertaken to ascertain the prevalence and drug sensitivity pattern of causative agents of mastitis in and around Namakkal, Tamilnadu, India. 
 
Materials and Methods: A total of 74 milk samples were collected and bacterial isolates from 72 samples were obtained and subjected to in-vitro chemotherapeutic sensitivity test. 
 
Results: Out of 72 samples, 32 (44.44%) were found positive for Staphylococci species, 4 (5.5%) for Streptococci species, 30 (41.66%) for E.coli and 6 (8.33%) for Klebsiella species. The drug sensitivity test performed irrespective of isolates, revealed sensitivity of organisms to various antibiotics and none of the isolates were found to be sensitive to penicillin G. 
 
Conclusion: Enrofloxacin was found to be more effective antibiotic among all the tested antibiotics.


Introduction
development of resistance to antimicrobials.The multiplicity of the cause and emergence of resistance Mastitis is the inflammation of udder tissue due to indiscriminate and prolonged use of antibiotics causing pathological changes in udder parenchyma and in absence of antibiogram is a major hurdle in the characterized by physical, chemical and microbiocontrol of mastitis.logical changes in milk [1].It is one of the To overcome this problem and with due economically important diseases of dairy animals consideration to the economic losses, the present study affecting quality and quantity of milk.Mastitis in dairy was undertaken to ascertain current drug sensitivity animals leads to economic losses in different forms viz.

low graded (7%) [2]. The global estimated economic
A total of 74 milk samples were aseptically loss per year due to mastitis amounts to USD 35 billion collected from cows suffering from clinical mastitis [3].Whereas Indian Dairy Industry suffers a total from various places of Namakkal district of Tamil monetary loss of over Rs.6000 crore per year [4].
Nadu.The udder of each cow was thoroughly washed Further mastitis has public health importance as it is initially with potassium permanganate solution one of the sources for communicable diseases such as (1:1000) and wiped with clean cloth to allow drying.tuberculosis, brucellosis, staphylococcal toxemia, The mid stream milk was sampled using sterile swab septic sore throat, gastroenteritis etc. [5].
aseptically and transported to the laboratory in ice pack Mastitis is produced by interplay of the variety of for in-vitro chemotherapeutic sensitivity test.pathogenic agents' viz.bacteria or fungus and The milk samples were cultured in Nutrient agar, management practices stressing the defense of udder.
Mac Conkey agar, EMB agar, Sabourads dextrose agar Over 135 microorganisms have been isolated from and nutrient broth (Himedia) and incubated at 37º C for bovine inflammatory infections and bacteria are one of 36 hours.The typical colonies were sub-cultured in a the major etiological agents of mastitis [6].Mastitis is selective broth and subjected to battery of tests viz., considered to be the most common cause of Gram reaction, oxidase, catalase, IMViC, motility and indiscriminate antibiotic use in dairy animals which growth on TSI slant for biochemical identification.leads to treatment failure, escalated treatment costs and Then, the colonies were transferred to Muller Hinton agar plates and streaked.Drug sensitivity test was done by using Kirby -Bauer discs.The antibiotic discs (Himedia) viz., amoxicillin (30 µg), ciprofloxacin (5 µg), enrofloxacin susceptibility test of bacterial isolates revealed the (10 µg), gentamicin (10 µg), oxytetracycline (30 µg), sensitivity in the descending order of Enrofloxacin penicillin -G (10 units), and streptomycin (10 µg) were (94.44%),Ciprofloxacin (91.66%),Oxytetracycline placed on the surface of charged agar plates aseptically (88.55%),Amoxicillin (80.55%),Gentamicin at equidistant from each other.The plates were (80.55%), and Streptomycin (55.5%).Enrofloxacin incubated at 37º C for 36 hours.The susceptibility of has been found to be the most sensitive (94.44%) organisms to different drugs was observed by among the battery of antibiotics used in the invitro measuring zone of inhibition [7].

Resutls and Discussion
other than enroflooxacin as most effective drug from Out of 74 samples of mastitic milk, 72 samples the studies done in various parts of country contrary to showed bacterial growth and two samples showed for the present findings.The studies [25-28] from different yeast (Candida species) growth.Growth of yeast was parts of Tamil Nadu reported the sensitivity of mastitis confirmed by inoculating the milk sample in causative organisms to other antibiotics.Isolates in the Sabourads-dextrose agar.Out of 72 samples, 32 present study showed moderate sensitivity or (44.44%) were found positive for Staphylococci resistance to Gentamicin, Streptomycin and Penicillin species, 4 (5.5%) for Streptococci species, 30 (41.66%) -G.Indiscriminate and frequent use of these for E.coli and 6 (8.33%) for Klebsiella species.The antibiotics in animals could be the reason for their drug sensitivity test performed irrespective of isolates, ineffectiveness against bacterial isolates.A similar revealed sensitivity of organisms to various antibiotics observation of resistance to Penicillin was also and none of the isolates were found to be sensitive to observed [10,11,23,25,28,29].

penicillin G (Table-1). The result of biochemical tests
The alarming level of less susceptibility or more are given in Table -2.
resistance of organisms to a particular drug might be The present study revealed that Staphylococci sp.
due to the prolonged exposure to the same drug.was the major pathogen causing mastitis with high Considering the varied spectrum of pathogens prevalence followed by E. coli which is in accordance resulting in mastitis in different geographical areas its with other reports [8][9][10][11][12][13].The reports from other parts control needs the selection of suitable antimicrobial by of the country [14][15][16] also indicate the highest establishing an antibiogram.Hence, the control of prevalence of Staphylococci followed by other mastitis should be by a definite regime of adminismastitogenic bacteria.The higher incidence of tration of antibiotics and holistic approach to the Staphylococci indicates unhygienic milking practices disease management.as this pathogen is mainly spread during milking via Authors' contribution milkers' hands [17].This also might be due to harbouring of the organism in the skin, udder and milk MJ and SK conceived the idea and were involved in lab of the infected gland which acts as reservoir [18,19].
analysis along with GV.MJ and BPB collected samples Whereas prevalence of E.coli is an indication of poor from the field.GV and SK drafted and revised the hygienic practices in dairy environment, as these manuscript.All authors read and approved the final organisms originate from the cow's environment and manuscript.infect the udder through the teat canal.Contamination  In Jabalpur, Madhya Pradesh, India.Buffalo Bulletin, 24 (1): carry out the work.

Table - 1
. Kirby-Bauer disc sensitivity test 3-9.Competing interests 15.Sharma, A. and Sindhu N. (2007) Occurrence of clinical and subclinical mastitis in buffaloes in the State of Haryana Authors declare that they have no competing interest.