Drug resistance, plasmid profile and random amplified polymorphic DNA analysis of Iranian isolates of Salmonella enteritidis

The aim of this study was to characterize 49 Salmonella Enteritidis (SE) isolates from different sources (poultry, human, cow, poultry house environment) in Iran with respect to drug resistance, plasmid profile, and random amplified polymorphic DNA (RAPD) analysis. Antimicrobial susceptibility test to 29 agents found 33 resistance patterns among the isolates. No resistance was observed to danofloxacin, levofloxacin, norfloxacin, ceftriaxone, imipenem, and amikacin. The highest resistance (38.8%) was observed to flumequine. Thirty (61.2%) isolates were multidrug-resistant. Six plasmid profiles were detected and a 68-kb plasmid was found in 98% of isolates. Two different primers, MK22 and P1254, were used for RAPD analysis which each produced six profiles. For MK22 and P1254 primers, 83 and 86% of the isolates, respectively, belonged to one profile only and the rest distributed among other 5 patterns. The findings of the present study showed that SE isolates from poultry-related sources were closely related to human SE isolates. This study confirmed previous evidence that molecular techniques such as RAPD-PCR or plasmid profile alone do not demonstrate sufficient discriminatory power in epidemiological studies and a combination of patterns obtained by several techniques will provide more discriminatory power.