The widespread of MDR S. aureus is becoming a serious challenge in public health. Recently, therapeutic options against MDR S. aureus have become limited, causing morbidity and mortality in hospitalized patients [19]. Inappropriate use of antibiotics in hospitals and communities has resulted in an increasing resistance to various antibiotics, especially beta lactam antibiotics [20].
In this study, the maximum resistance of MRSA isolates was to beta lactam antibiotics such as penicillin (92%), followed by erythromycin, azithromycin (66%) and ciprofloxacin (54%). The rate of resistance to antibiotics was higher in MRSA isolates in comparison with MSSA isolates. Rate of resistance to cholrampincol, rifampicin, nitrofurantoin and gentamicin was lower than the other antibiotics in MRSA and MSSA. These were in line with other studies from Iran [20], which can be due to wide use of these antibiotics to treat various infections in hospitals. In the present study, high rate of resistance to clindamycin, erythromycin, ciprofloxacin antibiotics was consistent with the data from a previous study in Iran [18]. In this study, out of 31 isolates of S. aurous isolated from outpatients, 12 and 19 isolates were MRSA and MSSA, respectively. At present, resistance to different antibiotics is on the rise, which can lead to inappropriate use of antibiotics in communities, hospitals and agricultural industry. Hence, infective infection control policies in hospitals can be the cause of increased antibiotic resistance in the communities and hospitals[21].
In our study, vancomycin antibiotic was a highly effective against MRSA isolates, which was consistence with other studies in Iran [11, 20, 22].
MRSA isolates are one of the most common causes of threat to public health [23]. In the current study, the prevalence of MRSA isolates was 31.4%, which was lower than what was reported in other studies in Iran [24-27]. The differences in the distribution of this gene could support the different infection control policies, studied population, the diversity types of clinical isolates, inappropriate use of antibiotics, and prescribing certain antibiotics in different geographic areas.
SCCmec typing provides useful information about the resistance of genes to methicillin, and to identify the origin of strains [28, 29]. In our study, SCCmec typeIII was the most common type, which was similar to other reports in Iran and other countries [11, 18, 22, 26, 27, 30, 31]. However, in a study by Havaie et al. SCCmec type ІV was the most common SCCmec type [32]. In the current study, frequency of SCCmec type IV in comparison to other SCCmec type was high (20.1%), which might be due to their small size that can spread among S. aureus isolates collected from hospitals and communities [13]. Rate of SCCmec type IV among outpatients (74.2%) and hospitals (25.8%) was reported to be the highest amongst the samples isolated from the skin. The results of SCCmec typing revealed that types ІІ, ІІІ, ІV were the most common types in outpatients. These results show that MRSA isolates could be transmitted from hospitals to communities and vice versa, while type IV belongs to CA-MRSA.
Among the MRSA isolates, 15 different spa types were revealed, and Spa type t030 was the most frequent type (n=12, 24%) followed by Spa type t021 (n=10, 20%). In Iran, different types of spa were reported[11, 18, 20, 32] and the most common types are as follows: t021,t037,t701,t790 related to MRSA isolates, which is similar to other studies in Iran [18, 20], but in our study, spa types t030, t386, t314, t1877, t325, t345, t304, t003, t81 and t018 were detected. In this study, spa type t037 belonged to SCCmec type ІІІ, which is in agreement with Darban et al. study from Iran [11]. Spa type 790 is considered as SCCmec type ІV and other spa types belonged to different SCCmec types, which were in line with other studies, for example spa type t030 belong to SCCmec types of І, ІІ, ІІІ, ІV [18]. According to previous data, t030 spa type is commonly recognized as MRSA, which was similar to our study [11, 18].
In different countries, various spa types among clinical isolates were reported. In Europe, spa t032, in Asia, spa type t030, in America, t008, in Africa, t037 and in Australia, t202 were the most common types [2].
As far as we know, in the present study, spa type t003, t386, t1877, t314, t186, t1816, t304, t325, t345 is the first to be reported in Iran. Spa type t003 was reported in European and American countries, and its presence in Iran might be due to the spread of this spa from one continent to another.