A Study on Class I Integrons and Antimicrobial Resistance among Clinical Staphylococci Isolates from a Turkish Hospital

Jundishapur J Microbiol

Seyedjavadi

Udo

et al. 2016

Background: Methicillin resistant Staphylococcus aureus (MRSA) is an increasingly common hospital pathogen in burn patients, which is known to cause over 50% of burn related deaths. One of the serious threats associated with clinical isolates of MRSA is multi-drug resistance, which is associated with integrons. Objectives: The aim of this study was to determine the distribution and molecular types of MRSA in burn patients and their carriage of integrons. Methods: During a 7-month period, 106 MRSA isolates were collected from burn wounds of patients admitted to a referral burn hospital in Tehran. Antimicrobial susceptibility testing (AST) was performed for 12 antimicrobial agents. Polymerase chain reaction (PCR) was used to detect nucA, mecA, pvl and tsst-1 genes, and class 1 and 2 integrons. Multiplex PCR technique was used to determine the Staphylococcal cassette chromosome mec (SCCmec) types of MRSA strains. All isolates were genotyped by staphylococcal protein A (spa) typing. Results: AST showed the lowest rate of resistance to quinupristin-dalfopristin (19.8%), mupirocin (31.3%), and rifampicin (37.7%). All isolates were susceptible to vancomycin, teicoplanin, and linezolid. Multi-drug resistance was observed in 97% of isolates. The most SCCmec type was SCCmec type III (98.1%) while only 2 (1.9%) MRSA isolates harbored SCCmec type IV. SCCmec types I, II, and V were not detected. The study revealed the presence of class 1 integron in 58 (54.7%) isolates and class 2 integron in 3.8% of isolates. Six different spa types of t030 (66%), t037 (14.2%), t065 (9.4%), t1358 (4.7%), t937 (3.8%), and t084 (1.9%) were identified amongst the isolates. Conclusions: The study revealed a high prevalence of multi-drug resistance (MDR), class 1 integron, SCCmec type III, and spa type t030 amongst MRSA associated with burn wounds in an Iranian hospital. The existence of SCCmec type III in burn patients emphasizes the nosocomial origin of these strains.

Section: Discussioncontrasting

confidence: 99%

Molecular Characterization and Distribution of Class 1 Integron-Bearing Methicillin Resistant Staphylococcus aureus Strains in Burn Patients, Tehran, Iran

Jundishapur J Microbiol

Seyedjavadi

Udo

et al. 2016

“…According to the literature, MRSA strains are resistant not only to beta-lactams but also to macrolides, lincosides, and aminoglycosides (6,8,18). In the present study, the majority of the MRSA isolates were resistant to ampicillin (100%), ciprofloxacin (94.5%), gentamicin (98.2%), erythromycin (90.9%), tetracyclin (87.3%), and clindamycin (98.2%), which is in line with the findings reported in Iran (8), Croatia (17), and Turkey (19). The rate of resistance to tested antibiotics, with the exception of amikacin among MRSA isolates, was higher than those among MSSA isolates, which is in accordance with the findings reported by Yu et al (20).…”

Section: Discussionsupporting

confidence: 91%

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

Jundishapur J Microbiol

Abiri

Nasirian

et al. 2018

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.

“…In this survey, the presence of class 1 and 2 integrons was confirmed in 45 (56.3%) and 15 (18.7%) isolates, respectively. These findings are consistent with previous studies in which the rate of detection of integron class 1 was more than integron class 2 (6,28,29). In the study of Xu et al in China, out of 30 S. auerus isolated from environment and surgical patients, 16 (53%) clinical and environmental isolates were positive for the class 1 integrase gene (6).…”

Section: Discussionsupporting

confidence: 91%

“…In a study conducted by Guney et al that investigated the presence of class 1 integron in MRSA isolated from a 1150-bed training and research hospital located at Black Sea region in Turkey, one hundred clinical MRSA isolates were investigated. The result revealed that none of the isolates harbored class 1 integron (29). The high prevalence of class 1 integron in our survey strongly demonstrated that class 1 integron might serve as a reservoir for antimicrobial resistance in Iranian S. aureus strains.…”

Section: Discussionmentioning

confidence: 58%

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

Seyedjavadi

Azad

et al. 2016

Arch Clin Infect Dis

Background: Nosocomial Staphylococcus aureus is known as an important clinical pathogen in health care, hospital, and community settings. One of the serious threats associated with clinical isolates of Staphylococcus aureus is multi-drug resistance associated with integrons. Objectives: The objective of the present study was to investigate antimicrobial susceptibility patterns, frequency of class 1 and 2 integrons, and associated gene cassettes in different spa types of Staphylococcus aureus isolated from intensive care units (ICUs). Methods: During a five-month descriptive cross-sectional study, 80 Staphylococcus aureus strains isolated from hospitalized patients in ICU wards in five hospitals of Tehran, Iran were investigated. Staphylococcus aureus isolates were submitted to susceptibility testing and Polymerase Chain Reaction (PCR) to detect mecA gene, class 1 and 2 integrons, and associated gene cassettes. All the isolates were genotyped by staphylococcal protein A (spa) typing. Results: The overall prevalence of Methicillin-resistant Staphylococcus aureus (MRSA) was found to be 86.2%. All the isolates were susceptible to vancomycin, teicoplanin and linezolid and resistant to penicillin and ampicillin. All the 80 Staphylococcus aureus isolates were observed to be multi-drug resistant. Class 1 and 2 integrons were commonly found in 56.3% and 18.7% of the isolates, respectively. Six different gene cassettes were detected in class 1 integron (aadA2, aadB, blaoxa, aacA4, cmlA6, and catB) and three were found in class 2 (dfrA1, aadA1, and sat2). Gene cassette arrays aadA, aadB, blaoxa, and aacA were common in the two integron classes of Staphylococcus aureus isolates. Five different spa types of t790, t030, t969, t7580 and t1425 were identified among our isolates where spa type t790 was the most predominant spa type among integron-bearing Staphylococcus aureus strains. Conclusions: The present study reports on a high rate of multi-drug resistance, the predominance of the frequency of class 1 integron, and the emergence of spa type t790 among Iranian Staphylococcus aureus strains. The results revealed that the dissemination of multi-drug resistance among Staphylococcus aureus isolates may be associated with the presence of integrons. Therefore, continuous surveillance to monitor integrons and the associated gene cassettes among nosocomial pathogens, especially Staphylococcus aureus, is essential.