DMA macrorestriction analysis by pulsed-field gel electrophoresis of Pseudomonas aeruginosa isolates from mastitis in dairy sheep

摘要

A broat range of bacteria are responsible for mastitis in small ruminants, but Staphylococcus aureus and Staphylococcus epidermidis are the most prevalent species (Las Heras and others 1999a). Of the Gram-negative bacteria, species such as Mannheimia haemolytica and Pseudomonas aeruginosa arc also responsible for a significant proportion of cases of mastitis in dairy sheep (Lafi and others 1998, Scott and Jones 1998, Rapoport and others 1999). P. aeruginosa represents less than 10 per cent of the isolates from subclinkal mastitis (Lafi and others 1998), but it is responsible for outbreaks of clinical mastitis with significant sanitary and economic repercussions (Las Heras and others 1999b, Rapoport and others 1999). Molecular characterisation studies provide relevant information towards greater knowledge of the epidemiology of the different bacterial pathogens which cause mastitis, as well as for the establishment of rational control measures. These studies have generally been carried out in dairy cows with bacteria which arc of higher clinical significance, mainly with S aureus (Fitzgerald and others 1997, Lange and others 1999, Buzzola and others 2001, Joo and others 2001). However, there is a lack of information about the epidemiological relationship of the clinical isolates in general, and P. aeruginosa in particular, which are responsible for mastitis in dairy sheep. Different techniques have been used for the characterisation of clinical isolates of P. aeruginosa, but pulsed-field gel electrophoresis (PFGE) has been shown to have the highest discriminatory power for typing epidemiologically unrelated strains (Grundmann and others 1995). The aim of the study described in this short communication was the characterisation by PFGE of P. aeruginosa isolates recovered from cases of mastitis in dairy sheep.