~ 489 ~ Journal of Entomology and Zoology Studies 2017; 5(2): 489-492 E-ISSN: 2320-7078 P-ISSN: 2349-6800 JEZS 2017; 5(2): 489-492 © 2017 JEZS Received: 13-01-2017 Accepted: 15-02-2017 Asmaa H Abdullah University of Baghdad -College of Veterinary Medicine, Microbiology Department, Iraq Ban N Nadhom University of Baghdad -College of Veterinary Medicine, Microbiology Department, Iraq Hind H Al-Ammiri University of Baghdad -College of Veterinary Medicine, Microbiology Department, Iraq Correspondence Asmaa H Abdullah University of Baghdad -College of Veterinary Medicine, Microbiology Department, Iraq Isolation and Identification of Serratia marcescens from Bovine Mastitis infections in Iraq and their Susceptibility to Antibiotics Asmaa H Abdullah, Ban N Nadhom and Hind H Al-Ammiri Abstract This study was conducted to isolate Serratia marcescens from bovine mastitis for the first time in veterinary medicine field in Iraq and their susceptibility against antibiotics. One hundred and fifty samples from case of mastitic milk of cow were collected from College of University of Baghdad/College of Veterinary Medicine, University of Baghdad/College of Agriculture, Dora zone, Radhwanya zone and Abu-Ghraib zone. Cultured by selective and differential media then Gram stain were done. After purification of cultured bacteria biochemical tests were done and confirmed by API 20 E System and RapID TM ONE System kit. Results showed that 6 (4%) samples out of 150 samples were positive for Serratia marcescens and it’s the first time to isolate in veterinary medicine field. The resistance of these isolates against antibiotics Gentamycin (30 mg), Imipenem (10 mg),Ciprofloxacin (5 mg),Nalidixic acid (30 mg), Ampicillin (10 mg), Cefotaxime (30 mcg), Amikacin (30 mg), Chloramphenicol (30 mg), Tetracyclin (10 mg) and Amoxicillin-Clavulanic acid (20/10 mg) were studied. The results showed that Serratia marcescens were resistant 100% to Ampicillin, Imipenem and Tetracyclin, 66.66% to Cefotaxime and susceptible 100% to Ciprofloxacin, 83.33% to Gentamycin, 66.66% to Chloramphenicol and 50% to Nalidixic acid. While Intermediate 83.33% to Amoxicillin- Clavulanic acid, 50% to Nalidixic acid and 33.33% to Chloramphenicol and Cefotaxime. Keywords: Serratia marcescens, Bovine Mastitis, Susceptibility, Antibiotics 1. Introduction Serratia species are one of gram negative family it is opportunistic bacteria; classified in the ethnic group Klebsielleae and the large family Enterobacteriaceae, it`s also, a widespread in the environment [1] . Serratia marcescens is the most important pathogenic species of Serratia, rare reports have described disease consequential from infection with other type like from Serratia odorifera, Serratia plymuthica, Serratia liquefaciens, Serratia rubidaea and Serratia fonticola [2- 6] . Some strains of S. marcescens are capable of producing a pigment which is called prodigiosin, it`s ranges from dark red color to pale pink depending on the period of the colonies. Serratia are capable of thriving in diverse environments, like water, soil, and the digestive tracts of various animals, S marcescens has a weakness for growth on starchy foodstuffs, where the pigmented colonies are easily misguided for drops of blood [7, 8] . Mastitis almost occurred due to the effect of infection by bacteria or mycotic pathogens, about 140 microbial species; serovars have been isolated from the mammary gland. Pathogens causing mastitis in cattle are divided into two groups the major pathogens those that cause clinical mastitis and the minor pathogens those that normally cause subclinical mastitis [9-13] . A number of special kind of Serratia can act as a reason of mastitis, including S. marcescens, S. rubidaea and S. liquefaciens. Firstly the dry period is considered a major phase of infection [14, 15] secondly the lactation phase [16-18] . In spite of, the source of the outbreak was not detected the outbreaks of Serratia to cause mastitis have been occurred may be due to growing of the organism in a teat dip cup and in the bedding [16-20] . On the other hand, Poor hygiene and damage to teat ends are thought to elevate the rate of mastitis [21] . Albeit Serratia is considered to be an environmental microorganism, transmitted by the milking machine may occur [16] . Serological typing can be used to determine whether Serratia isolates belong to different strains, or to a single strain, from a point source or contagious transmission.