Determination of some of the virulance factors and antibiotic resistance of Klebsiella species isolated from milk and milk products offered for consumption in Ankara

In this study 80 samples of milk and milk products, which consist of 20samples of raw milk obtained from a dairy farm in Ankara, 20 samplesof pasteurized milk and 20 samples of white cheese of different brandsfrom different dairies, 10 samples of vanilla ice cream and 10 samplesof chocolate ice cream bought from different pastry shops, wereanalyzed between February 2005 and March 2006. Klebsiella specieswere isolated and identified by means of biochemical tests. Identifiedspecies were further characterized and analyzed in terms of virulencefactors such as siderophore production, serum resistance andhemolytic activity. Furthermore, the production of extended spectrumbeta Lactamase and antibiotic resistance characteristics were alsoanalyzed. Among 47 Klebsiella isolates, 43 isolates were identified asandKlebsiella pneumoniae, Klebsiella oxytoca Klebsiellarhinoscleromatis in 25 (58 %), 11 (26 %) and 7 (16 %) isolatesrespectively. 4 isolates which belong to the different Klebsiella specieswere not identified. Production of siderophore among 43 isolates wasstudied through Chrome Azurol Sulphate Agar and it was determinedthat 27 (63 %) isolates were siderophore producers. Their serumresistance was determined using human serum inactivated at 56oC and30 (70 %) isolates were found to be resistant to the human serum.Blood agar was used for the determination of the haemolytic activity ofthe isolates and 25 (58 %) of them were determined as haemolysinproducers. All of the isolates were established for the production ofextended spectrum beta Laktamases (ESBL) by the double discdiffusion method. 15 (35 %) of them were found as producers of ESBL.ESBL producer species were determined to be resistant to the newgeneration sefalosporins and monobaktams. All the Klebsiella isolateswere found as susceptible to meropenem, imipenem and amicasin andresistant to ampicilin and amoxicillin.