Detection of Integrons and Staphylococcal Cassette Chromosome mec Types in Clinical Methicillin-resistant Coagulase Negative Staphylococci Strains

Abstract

ObjectivesIntegrons are thought to play an important role in the spread of antibiotic resistance. This study investigates class 1 and 2 integron-positive methicillin-resistant coagulase-negative staphylococci strains isolated in Iran and characterizes their patterns of antimicrobial resistance.MethodsHundred clinical isolates of coagulase-negative staphylococci were characterized for integron content and staphylococcal cassette chromosome mec (SCCmec) type.ResultsSixteen isolates carried class 1 (intI1) integrons and four isolates carried class 2 (intI2) integrons. One resistance gene array was identified among the class 1 integrons (aadA1 cassette). The distribution of SCCmec types in 50 methicillin-resistant coagulase-negative staphylococci strains showed that SCCmec types III and V dominated among the tested strains.ConclusionThis is the first report of methicillin-resistant coagulase-negative staphylococci strains that carry two mobile genetic elements, including class 1 and 2 integrons and SCCmec, in Iran.

Investigation of SCCmec types I–IV in clinical isolates of methicillin-resistant coagulase-negative staphylococci in Ahvaz, Southwest Iran

“…The rate of methicillin resistance in our study was 48.8% that was close to Namvar et al [19] and Hajiahmadi et al [23] results with 47.2% and 50%, respectively. In our study, the most common MR-CoNS isolates belonged to both of S. epidermidis and S. haemolyticus (45.45%) which was consistent with previous reports from Iran and other countries [3,23,24,25]. One of the species that so far has not been reported from other regions of Iran, but was isolated in Ahvaz city, was S. petrasii.…”

“…The prevalence of MR-CoNS in clinical samples has been reported between 47% and 91% in different cities of Iran [19,20,21,22]. The rate of methicillin resistance in our study was 48.8% that was close to Namvar et al [19] and Hajiahmadi et al [23] results with 47.2% and 50%, respectively. In our study, the most common MR-CoNS isolates belonged to both of S. epidermidis and S. haemolyticus (45.45%) which was consistent with previous reports from Iran and other countries [3,23,24,25].…”

“…This could be because of different protocols and panels of antibiotics used in various hospitals. Although in our study the lowest resistance was observed to linezolid (22.7%), this rate of resistance was high in comparison with many studies in Iran and other countries [23,28,29,30]. According to multinational and multicenter surveillance studies, more than 99% of coagulase-negative staphylococci and S. aureus clinical strains are sensitive to linezolid (31) [31].…”

“…The SCCmec is a mobile genetic element widely distributed among MR-CoNS species that varies depending on the host species, various environments and geographical locations [16]. In the present study, the most abundant SCCmec type among MR-CoNS was type I (45.5%), whereas in other studies in Iran SCCmec type IV, III and V were more frequent [20,23,28]. It isn't easy to compare our results with other results in Iran because in many studies the diversity of SCCmec type has been evaluated only among S. epidermidis [19,23,28].…”

“…In the present investigation, the susceptibility patterns of MR-CoNS were at variance with some other studies from Iran. For example in Hajiahmadi et al [23] and Havaei et al [27] studies the highest resistance was observed to trimethoprim-sulfamethoxazole (56%) and ciprofloxacin (65%) respectively. This could be because of different protocols and panels of antibiotics used in various hospitals.…”