Epidemiological and molecular characteristics of Klebsiella pneumoniae infection in bovine dairy herds

Abstract

Mastitis is an inflammatory response of the mammary gland, being the most frequent dairy cattle infection, responsible for major economic losses. Nearly 140 microbial agents have already been isolated from bovine mammary gland and may be a cause of mastitis, including its subspecies and serovars. Based on its epidemiology and the infection pathophysiology, these agents can be classified as infectious, environmental and opportunistic. Klebsiella. pneumoniae (K. pneumoniae) is a common environmental agent in clinical and subclinical mastitis in dairy herds. The mastitis caused by K. pneumoniae may be particularly severe due to the fact that there is a weak response by animals to traditional antibiotics and there is a rapid development of toxic shock and death. A new bacteria enzyme class know as extended spectrum ²-lactamases (ESBL) have become a major concern in public health and its resistance to drugs, and are commonly present in K. pneumoniae strains. They enhance the bacterial resistance capacity, leading to a greater agent dissemination. Klebsiella is an agent that can be isolated from various locations within the environment of animals and different genotypes of K. pneumoniae can cause mastitis in the same herd. This study aimed to evaluate the occurrence of infectious and environmental agents in cases of clinical and subclinical bovine mastitis in ten dairy farms located in São Paulo State, isolate and identify biochemically the samples of K. pneumoniae founded on the milk of the animals, in the expansion tank, in the milking room and in the "free stalls", identify ESLB producers strains, and to perform clonal identification of samples of K. pneumoniae isolated by the technique of electrophoresis in pulsed electric field (Pulsed Field Gel Electrophoresis - PFGE) in order to determine the distribution of genotypes of K. pneumoniae isolated trying to better understand the epidemiology of this agent and seeking new strategies for mastitis prevention and control. (AU)