Studies on Persister Cells Emerged From Some Gram Negative Bacterial Cultures A Thesis

Abstract

Atotal of 40 clinical bacterial isolates were obtained from different specimens. The isolates were identified using the classical phenotypic characteristic tests including API 20E identification kit. The results showed that Proteus mirabilis(55%), E.coli (17%), P. aeruginosa (12%), Klebsiella pneumoniae (10%), Enterobacter cloacae (3%), Acinetobacter baumannii (3%) comprised the different bacterial species of the collected isolates. The agar dilution technique was used to determine the minimum inhibitory concentration of the collected isolates against ciprofloxacin. The results showed that sensitive isolates constituted (60%), resistant isolates (32%) and intermediate isolates (8%) of the collected isolates. Two isolates were selected for completing the study andthe criteria of the selection depended on choosing most sensitive isolates as well as two different bacterial species not commonly reported in literature for persistence phenomenon study. A Klebsiella pneumoniaeisolate (MIC = 0.5μg/ml) and AProteus mirabilisisolate (MIC= 0.031μg/ml) fulfilled the selection criteria and they were of codes 33 and 17, respectively.