Open Access
ARTICLE
Molecular typing of methicillin and vancomycin-resistant Staphylococcus aureus isolated from clinical specimens by doublelocus sequence typing (DLST) method
SOHEILA HASANIAN1, NOUR AMIRMOZAFARI2, AHMAD FARAJZADEH SHEIKH3,*, IRAJ MEHREGAN1
1 Department of Biology, Science and Research Branch, Islamic Azad University, Tehran, Iran
2 Department of Microbiology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
3 Department of Microbiology, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
* Address correspondence to: Ahmad Farajzadeh Sheikh. Email:
BIOCELL 2020, 44(3), 411-419. https://doi.org/10.32604/biocell.2020.08976
Received 30 October 2019; Accepted 11 May 2020; Issue published 22 September 2020
Abstract
Methicillin-resistant
Staphylococcus aureus (MRSA) strains are the essential cause of infections in communities and
hospitals. The present study was conducted to determine the molecular typing of MRSA, isolated from hospitalized patients,
using the double-locus sequence typing (DLST). In total, 280
S. aureus isolated from clinical specimens by phenotypic
(catalase, coagulase, DNase, oxacillin, vancomycin screening agar and antibiotic disk diffusion), and molecular methods
(PCR for determining the
mecA,
vanA and
nuc genes). The DLST and sequencing was performed for MRSA containing
mecA. Out of 280 specimens, confirmed as Staphylococcus aureus (S. aureus), 123 (43.9%) strains were MRSA. The
highest resistance toward the erythromycin (15 μg), followed by ciprofloxacin (5 μg), clindamycin (2 μg), tetracycline (30
μg), gentamicin (10 μg) and rifampicin (5 μg), was 98.3%, 97.5%, 94.3%, 90.2%, 83.7% and 41.4%, respectively. Also, the
least resistance (0%) was observed in each of teicoplanin (30 μg), linzolide (30 μg), and vancomycin (30 μg). All (100%)
of MRSA strains had the
mecA, and none of them have had the vanA. The results of DLST showed that the most
common sequence types were BPH 2003 and 0217. The DLST type 18-32 was a significant cluster of MRSA. By
sequencing MRSA and comparing the dominant types via the DLST, it is possible to establish the etiology of the disease
in a much shorter time, and prevent the complications of the disease. Therefore, the combination of partial sequences of
clfB and
spa can serve as useful genetic markers for MRSA typing. It concluded that the MRSA in our region was
relatively high, but no vancomycin resistance was found. The majority of the MRSA DLST type was 18–32.
Keywords
Cite This Article
HASANIAN, S., AMIRMOZAFARI, N., SHEIKH, A. F., MEHREGAN, I. (2020). Molecular typing of methicillin and vancomycin-resistant
Staphylococcus aureus isolated from clinical specimens by doublelocus sequence typing (DLST) method.
BIOCELL, 44(3), 411–419. https://doi.org/10.32604/biocell.2020.08976