Distribution of Staphylococcal cassette chromosome mecA (SCCmec) types among coagulase-negative isolates from healthcare workers in the North-West of Iran.

OBJECTIVES

Methicillin-resistant coagulase-negative (MR-CoNS) are recognized as one of the major causes of healthcare-associated infections in hospitals. The present investigation aimed to study the prevalence of Staphylococcal cassette chromosome mec (SCCmec) types, along with aminoglycoside modifying enzymes (AMEs) genes in the nasal carriage of MR-CoNS in the north-west of Iran.

MATERIALS AND METHODS

To assess the potential of coagulase-negative as hidden reservoirs for antibiotic resistance, we analyzed the antimicrobial susceptibility of MR-CoNS using the disk diffusion method. In addition, PCR and multiplex PCR assays were performed to determine the prevalence of AME encoding genes and SCCmec types in methicillin-resistant coagulase-negative isolates.

RESULTS

A total of 51 MR-CoNS isolates were recovered from the anterior nares of healthcare workers. The observed resistance rates to tobramycin, gentamicin, cotrimoxazole, kanamycin, erythromycin, tetracycline, and ciprofloxacin were 74.5%, 68.5%, 57%, 53%, 51%, 49%, and 8%, respectively. Of the 51 tested MR-CoNS isolates, 2(4%) were harboring type I, four (8%) were type II, six (12%) type III, eleven (21.6%) type IVa, two (4%) type IVb, two (4%) type IVc, six (12%) type IVd, and two (4%) type V. The rates of prevalence of the aminoglycoside modifying enzyme genes were as follows: (28 cases, 55 %), ant (20 cases, 39%), and the gene (9 cases, 17.6 %).

CONCLUSION

Subtypes IVa and IVd were the most prevalent SCC elements, and aac (6')/aph (2'') was the most common AME gene detected among the MR-CoNS isolates.