Resistance-Gene Cassettes Associated With Salmonella enterica Genotypes.
BACKGROUND
The epidemiology of salmonellosis is complex because of the diversity and different serotypes of Salmonella enterica (S. enterica) that occur in different reservoirs and geographic incidences.


OBJECTIVE
To determine the genotype distribution and resistance-gene content of 2 classes of integron among S. enterica isolates.


METHODS
Thirty-six S. enterica species were isolated and tested for their serological distribution and the resistance-gene contents of 2 classes of integron, as well as for their genetic diversity, using the pulsed-field gel electrophoresis (PFGE) genotyping method.


RESULTS
Serogroups E (36.1%) and D (30.5%) were dominant among the isolates. All of the isolates in serogroup D belonged to the serovar enteritidis. The aadA1 gene was found within all resistance-gene cassettes. We observed 4 common and 26 single pulsotypes among the isolates, which indicated a high degree of genetic diversity among the isolates. Using the PulseNet International standard protocol, it was found that these isolates were different from those reported previously in Iran.


CONCLUSIONS
The presence of a few common and new pulsotypes among the isolates suggests the emergence and spread of new clones of S. enterica in Iran.
Department of Bacteriology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran b.bakhshi@modares.ac.ir.
Bita
B
Bakhshi
Department of Biology, Science and Research Branch, Islamic Azad University, Tehran, Iran.
Mohsen
M
Ghafari
Department of Bacteriology, Pasteur Institute of Iran, Tehran.
Mohammad R
MR
Pourshafie
Department of Molecular Medicine, Pasteur Institute of Iran, Tehran.
Behnaz
B
Zarbakhsh
Department of Science, Health and Education, University of the Sunshine Coast, Queensland, Australia.
Mohammad
M
Katouli
Department of Microbiology, Reference Health Laboratories Research Center, Ministry of Health and Medical Education, Tehran, Iran.
Mohammad
M
Rahbar
Department of Microbiology, Reference Health Laboratories Research Center, Ministry of Health and Medical Education, Tehran, Iran.
Masoud
M
Hajia
Department of Biology, Science and Research Branch, Islamic Azad University, Tehran, Iran.
Neda
N
Hosseini-Aliabad
Antimicrobial Resistance Research Center, Iran University of Medical Sciences, Tehran, Iran.
Mina
M
Boustanshenas
D030561:Databases, Nucleic Acid / Q000706:statistics & numerical data; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics*; D005838:Genotype; D006801:Humans; D032023:Integrons / Q000235:genetics*; D007492:Iran / Q000453:epidemiology; D008826:Microbial Sensitivity Tests; D012480:Salmonella Infections / Q000175:diagnosis* / Q000453:epidemiology; D019779:Salmonella enterica / Q000235:genetics* / Q000302:isolation & purification
Salmonella enterica; genetic diversity; integrons; resistance, gene cassettes; serogrouping