Authors: K M Osman W M M Hassan R A H Mohamed
Publish Date: 2014/02/18
Volume: 33, Issue: 8, Pages: 1323-1337
Abstract
The present study was undertaken to identify and characterise integrons and integrated resistance gene cassettes among eight multidrugresistant MDR Salmonella serovars isolated from humans in Egypt Virulotyping by polymerase chain reaction PCR was used for the detection of the presence of virulence genes Integron PCR was used to detect the presence of class 1 in the MDR strains The associated individual resistance gene cassettes were identified using specific PCRs The isolated serovars were Salmonella Grampian C1 2/5 Larose C1 1/5 Hato B 1/5 and Texas B 1/5 Among the Salmonella serovars five Salmonella isolates showed the highest resistance to amoxicillin ampicillin chloramphenicol lincomycin gentamicin nalidixic acid streptomycin and trimethoprim 100 followed by neomycin norfloxacin and tetracycline 80 while the lowest resistance was recorded to colistin sulphate and ciprofloxacin in percentages of 20 and 40 respectively The invA avrA ssaQ mgtC siiD and sopB genes were detected in all isolates 100 while the spvC and gipA genes were totally 100 absent from all isolates The remaining three virulence genes were diversely distributed as follows the bcfC gene was detected in all isolates except Salmonella Hato 80 the sodC1 gene was detected only in Salmonella Grampian and Salmonella Texas 60 and the sopE1 gene was detected only in Salmonella Grampian Hato and Texas 60 Class 1 integrons were detected in 90 of the MDR isolates comprising serovars Muenster Florian Noya Grampian Larose Hato and Texas Of the class 1 integronpositive isolates 45 harboured Salmonella genomic island 1 SGI1 either right junction or right and left junction having an ACST phenotype Of the class 1 integronpositive isolates 44 harboured integron gene cassette aadA2 while 11 harboured the floR gene present in multidrug resistance flanked by two integrons of SGI1 The results of the present study indicate that class 1 integrons carrying gene cassettes conferring resistance mainly to aminoglycosides are widespread among the MDR Salmonella serovars isolated from humans in Egypt indicating the important role of these genetic elements in the dissemination of multidrug resistance
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