Distribution of spa Types, Integrons and Associated Gene Cassettes in Staphylococcus aureus Strains Isolated From Intensive Care Units of Hospitals in Tehran, Iran

Self Cite

Background: Most methicillin-resistant Staphylococcus aureus (MRSA) infections occur in health care settings; therefore, it is important to know about antimicrobial susceptibility, and carriage of virulence genes in S. aureus isolates. Objectives: The current study aimed at determining the prevalence of genes coding antimicrobial resistance, toxins, and adhesion factors among various SCCmec types of MRSA isolated from intensive care units (ICUs). Methods: From April 2016 to March 2017, a total of 200 MRSA species were isolated from various clinical samples of patients hospitalized in ICUs. The Kirby-Bauer disk diffusion method was employed to determine resistance pattern. Conventional polymerase chain reaction (PCR) assay was utilized to demonstrate antimicrobial resistance, toxins, and adhesion genes. Different SCCmec types of MRSA strains were determine by the multiplex PCR assay. Results: Antibiotic susceptibility testing revealed that all the isolates were sensitive to linezolid, teicoplanin, and vancomycin. The frequency of high-level mupirocin-resistant MRSA was 5.5%. The presence of resistance genes ant(4')-Ia, aac(6')-Ie/aph(2"), tetM, msrA, ph(3')-IIIa, ermA, msrB, ermB, ermC, and mupA were detected 73.5%, 60.5%, 57.5%, 37%, 36.5%, 34.5%, 24%, 17%, 15% and 5.5%, respectively. The most prevalent adhesion genes were clfA (93.5%) followed by clfB (90%), fnbA (81.5%), fnbB (77%), can (51%), ebp (46.5%), and bbp (2.5%). The frequency of etb, eta, pvl, and tst genes were 4.5%, 9.5%, 21.5%, and 61.5%, respectively. Inducible macrolide-lincosamidestreptogramin B (inducible MLSB resistance; iMLSB), and constitutive MLSB (cMLSB) phenotypes were observed in 88 (44%) and 26 (13%) isolates. Different SCCmec types comprising type III (56.5%), type IV (25%), type II (11%) and type I (7.5%) were identified among the MRSA strains. Conclusions: Results of the current study showed a high prevalence of resistance to commonly used antibiotics that can be a serious threat to patients hospitalized in ICUs. Also, the current study findings showed that different SCCmec types causing nosocomial infections were associated with specific antimicrobial resistance, adhesion, and toxin gene profiles.

Section: Discussionmentioning

confidence: 99%

“…Isolates with D-test negative pattern were classified as MSresistant phenotypes (15). Multidrug resistance (MDR) is defined as resistance to at least 3 or more unique antibiotic classes in addition to beta-lactams (17). All the antibiotic disks used in the current study were supplied by Mast, UK.…”

Section: Antibacterial Susceptibility Testingmentioning

confidence: 99%

Distribution of Genes Encoding Toxin, Adhesion, and Antibacterial Resistance Among Various SCCmec Types of Methicillin-Resistant Staphylococcus aureus Isolated From Intensive Care Unit, Tehran, Iran

Abiri

Sepahi

Goudarzi

et al. 2017

Self Cite

“…Various techniques have been developed to determine the type of S. aureus strains, including multilocus sequence typing (MLST), coa typing, pulsed-field gel electrophoresis (PFGE), staphylococcal cassette chromosome mecA (SCCmec), spa typing, the mec-associated hypervariable region (dru), and the accessory gene regulator (agr) (8)(9)(10). SCCmec typing classified SCCmec elements based on their structural differences.…”

Section: Introductionmentioning

confidence: 99%

SCCmec and spa Typing of Staphylococcus aureus Strains Isolated from Patients with Urinary Tract Infection: Emergence of spa Types t426 and t021 in Iran

Goudarzi

Abiri

Nasirian

et al. 2018

Self Cite

Background: Urinary tract infection (UTI) is one of the most frequent types of infections in community and hospital settings. Objectives: The aim of the present study was to investigate antimicrobial susceptibility patterns and also to determine spa and SCCmec types of Staphylococcus aureus strains isolated from patients with UTI. Methods: During a 12-month period, 863 urine samples were investigated. In vitro susceptibility of isolates was performed using the Kirby-Bauer disk diffusion method. Moreover, conventional PCR was performed to detect mecA, nucA, spa, and toxin (pvl, tst) genes as well as Multiplex PCR to determine SCCmec types. Results: A total of 90 isolates (10.4%) were analyzed in the present survey. Methicillin resistance was observed in 61.1% of the isolates. In total, 25 isolates (27.8%) were positive for the pvl-encoding gene and 40 (44.4%) for tst-1 encoding gene. Based on a multiplex PCR assay, the 4 different SCCmec types were detected as type III (38.9%), followed by type II (31.1%), type IV (28.9%), and type I (1.1%). PantonValentine Leukocidin (PVL) positive isolates belonged to SCCmec type IV (14.4%) and II (13.3%). The 90 S. aureus isolates were classified to 10 spa types t037 (23.3%), t924 (15.6%), t383 (15.6%), t426 (12.2%), t044 (12.2%), t790 (6.7%), t084 (4.4%), t021 (4.4%), t7580 (4.4%), and t064 (1.2%). The spa types t044, t790, and t084 were obtained from methicillin-resistant S. aureus (MRSA) strains and spa types t924 and t7580 from methicillin-sensitive S. aureus strains. Conclusions: To the best of the author's knowledge, this is the first study on spa types t426 and t021 in Iran. Since the majority of strains isolated from patients with UTI were MRSA, detection of MRSA clones and their characteristics is necessary.

“…During the past several decades, in spite of introducing a variety of therapeutic measures including antibiotic therapy, Methicillin-resistant S. aureus (MRSA) strains have shown a remarkable ability in a rapid development of multi-drug resistance (MDR) (2, 3).…”

Section: Introductionmentioning

confidence: 99%

Molecular Characterization and Resistance Profile of Methicillin Resistant Staphylococcus aureus Strains Isolated from Hospitalized Patients in Intensive Care Unit, Tehran-Iran

Nezhad

Meybodi

Rezaee

et al. 2017

Self Cite

Background: Staphylococcus aureus is an important opportunistic pathogen and can cause a wide range of infections. The ability of this pathogen to successfully persist within the hospital and the community is largely due to its remarkable ability to acquire resistance against various antimicrobial agents. Objectives: The aim of this study was to determine the carriage of antibacterial resistance genes and virulence markers of S. aureus isolates from hospitalized patients in intensive care units in Tehran, the capital of Iran. Methods: In this cross-sectional study that was conducted during an 11-month period since March 2015 to January 2016, a total of 105 S. aureus strains were investigated. MRSA screening was performed by phenotypic and genotypic methods. The Kirby-Bauer disk diffusion method was used to assess the sensitivity of S. aureus strains. The strains were typed based on the polymorphisms in SCCmec types. The presence of resistance (ermA, ermB, ermC, mupA, msrA, msrB, tetM, ant (4´)-Ia, aac (6´)-Ie/aph (2˝), aph (3´)-IIIa) and toxin (etb, eta, pvl, tst) encoding genes were investigated by the polymerase chain reaction (PCR) technique. Results: In this study, 105 isolates of S. aureus were obtained from 299 various clinical specimens. Ninety five (90.5%) strains were confirmed as methicillin-resistant S. aureus. The lowest levels of resistance were related to quinupristin-dalfopristin (16.8%) while the highest levels of resistance were related to penicillin (94.7%). Multi-drug resistance was observed in 91.5% of the isolates. Type IV was the most prevalent SCCmec type (57.9%), followed by type III (22.1), type V (12.6%), I (5.3%), and II (2.1%). Overall, 25 isolates (26.3%) harbored PVL-encoding genes, and all of them belonged to SCCmec type IV. The presence of resistance genes ant(4´) ermA, ermB, ermC, msrA, msrB, and tetM was detected in 94.7%, 81.1%, 31.6%, 31.6%, 15.9%, 18.9%, 47.3%, 21.1%, 56.8%. The frequency of the etb, eta, and tst genes were 1.1%, 4.2%, and 32.6%, respectively. Conclusions:The results illustrated the diversity of antibacterial resistance and virulence gene profiles among different SCCmec types of S. aureus. The increased prevalence of methicillin-resistant S. aureus isolates containing different toxin and antibiotic resistance genes is a serious threat for the hospitalized patients in the intensive care units.