Genetic Characterization of Methicillin Resistant and Sensitive, Vancomycin Intermediate Staphylococcus aureus Strains Isolated from Different Iranian Hospitals

Abstract

Background. Global concerns have been raised due to upward trend of Vancomycin Intermediate Staphylococcus aureus (VISA) and Vancomycin Resistant Staphylococcus aureus (VRSA) reports which mean casting doubt on the absolute effectiveness of the last line of antibiotic treatment for S. aureus, vancomycin. Hence, epidemiological evaluation can improve global health care policies. Methodology. 171 Isolates of Staphylococcus aureus were collected from different types of clinical samples in selected hospitals in Isfahan, Mashhad, and Tehran, Iran. Then, they were evaluated by agar screening, disk diffusion, and MIC method to determine their resistance to vancomycin and methicillin. The isolated VISA strains were then confirmed with genetic analysis by the evaluation of mecA and vanA genes, SCCmec, agr, and spa type, and also toxin profiles. MLST was also performed. Results and Conclusion. Our data indicated that 67% of isolated S. aureus strains were resistant to methicillin. Furthermore, five isolates (2.9%) had intermediate resistance to vancomycin (VISA). In contrast to usual association of VISA with MRSA strains, we found two isolates of MSSA-VISA. Therefore, our data suggests a probable parallel growing trend of VISA towards MSSA, along with MRSA strains. However, more samples are required to confirm these primarily data. Moreover, genetic analysis of the isolated VISA strains revealed that these strains are endemic Asian clones.

Molecular Typing and Resistance Profiles of Vancomycin-IntermediateStaphylococcus aureusin Korea: Results from a National Surveillance Study, 2007-2013

“…were MSSA-hVISA in French hospital [10] and 2 isolates of 171 S. aureus were MSSA-VISA in Iran [28]. This suggests that it is as important to detect reduced vancomycin susceptibility in MSSA isolates as in MRSA, and there is an alarming need to pay attention to the occurrence of MSSA-hVISA/VISA.…”

Detection and Antimicrobial Resistance Properties of Staphylococcus aureus Strains Isolated from the Human Clinical Infections

“…The rate of resistance against this antibiotic was 8% in our study. Important role of methicillin resistant S. aureus (MRSA) as a causative agent of human clinical infections has been reported previously [21][22][23][24][25] . High prevalence of antibiotic resistance in our study is maybe due to the fact that the prescription of methicillin is very high in Iranian health center and hospitals.…”

The study of reduced susceptibility of methicillin resistant Staphylococcus aureus to various antibiotics with special reference to glycopeptides in a tertiary care hospital in central India

“…30 Havaei et al from Iran isolated 5 (4.34%) VISA by E strip and then subjected to PCR analysis. 31 Liaqat et al from Pakistan isolated 4 (8.16%) VISA by E strip and agar dilution. All the isolates showed growth on vancomycin screen agar.…”

“…It was also from blood sample at neurology department which is similar to our study. 31 In a study by Bhatawadekar et al, seven vancomycin and quinpristin-dalfopristin-resistant staphylococci were isolated from the blood samples of neonates and pediatric patients. 34 In our study, one VISA isolate was susceptible to cotrimoxazole and isolated from blood sample from neurology department.…”