Frequency of Aerobic Bacteria Associated with Subclinical and Clinical Mastitis among Lactating Goats in Khartoum State

Abstract

The aim of this study was to isolate and identify the bacterial agents that have association with subclinical and clinical mastitis among lactating goats in Khartoum State and to assess their antibiotic susceptibility patterns. One hundred and thirty two milk samples were collected from Khartoum North and Omdurman, 100 samples from apparently healthy goats, and 32 from mastitic one under aseptic condition; 15ml of milk were collected from each udder and transported to the laboratory in an ice box. Bacteria were identified to the species level using standard bacteriological procedures such as colonial morphology, Gram stain and their biochemical utilization behavior. Thirty two out of hundred (30%) apparently healthy goats showed bacterial growth, where as19/32(59.37%) mastatic goats milk showed bacterial growth from their milk. Isolated bacteria from both subclinical and clinical mastitis were as follows: subclinical bacteria were 22/100 (22%) gram positive cocci, of which 17/22(77.27%) were coagulase negative Staphylococci (CNS) and 5/22(22.72) were Staphylococcus aureus. Gram negative bacilli were 8/100(8%), of which 6/8(75%) were E. colli and 2/8(25%) were Pseudomonas aerogenosa. Bacteria isolated from clinical mastitis were 16/19(84.21) as Gram positive cocci of which, 5 Staphylococcus aureus, 5 CNS and 6 Streptococcus spp, while 3/19(15.78%) were Gram negative bacilli (2 E.colli and 1 Pseudomonas aerogenosa).

Thirty out of sixty (50%) of Saanene revealed bacterial growth where as nineteen out of seventy two (26.38) of local breed showed bacterial growth. The recovered Staphylococci and streptococci were found to be resistant to methicillin 38/38(100%), penicillin G 18/38(47.37%), on the other hand they were sensitive to vancomycin 38/38 (100%), gentamycin 35/38 (92.1 %), while Gram negative were sensitive to ciprofloxacin. In conclusion, CNS was significantly higher than other bacteria, so it was considered as the main cause of mastitis; the use of CMT is useful in detection of subclinical cases because thirty three out of hundred (33%) milk samples revealed CMT positive. Gentamycin, vancomycin and ciprofloxacin, were active against the recovered bacterial isolates.