Characteristics of Virulence Factors in Methicillin-Resistant Staphylococcus aureus Strains Isolated From a Referral Hospital in Tehran, Iran (original) (raw)
Related papers
Jundishapur Journal of Microbiology, 2012
This study has highlighted the presence of bacteriophage types among MRSA isolates to show the high potential of these isolates to produce broad spectrum of virulence factors. Background: Staphylococcus aureus is a common cause of infections among humans and animals and it is known as a community-acquired and nosocomial pathogen. Most of the isolates contain lysogenic phages which are responsible for production of various virulence factors such as enterotoxins, staphylokinase, β-lysin, lipase, exfoliative toxin A and Pantone-vlaentine leukociden (PVL). All staphylococcus isolates are classified in 6 groups according to their sensitivity to 27 known lysogenic phages. Objectives: This study was performed to detect the presence of bacteriophage types and determine antibiotic resistance pattern of methicillin resistant S. aureus (MRSA) isolates obtained from a tertiary care hospital in Tehran, Iran from 2008 to 2010. Materials and Methods: A total of 968 S. aureus isolates were collected from a tertiary care hospital in Tehran, Iran and identified at the species level by PCR and biochemical tests. Susceptibility to 17 antibiotics was determined. Then oxacillin and vancomycin minimum inhibitory concentration (MIC) of the resistant isolates were determined. Multiplex-PCR was used to detect 6 classes of prophages. Results: Out of the 968 isolates 247 isolates were resistant to methicillin. Highest antibiotic resistance was seen to penicillin (100%), erythromycin (89.8%), kanamycin (89.4%), ciprofloxacin (88.6%) and tobramycin (87.4) respectively. None of the MRSA isolates showed resistance to vancomycin, synercid and linezolid. MIC results indicated that 46.1 and 4.4% of isolates with high (MIC ≥ 128 µg/ml) and low level (MIC ≥ 4 µg/ml) showed resistance to oxacillin, respectively. Four different phage types and eight patterns of prophages were detected. All MRSA isolates contained at least one prophage. Totally, 2.8, 69.2 and 27.9% contained 5, 4 and 3 different prophage types, respectively. Conclusions: High prevalence of different classes of prophages indicating the potential to carry a broad spectrum of virulence factors and high oxacillin resistance were found in the MRSA isolates. Detection of SGF phage in 100% of the isolates indicates the ability of these isolates to produce virulence factors.
Jundishapur Journal of Microbiology, 2023
Background: In hospitals and communities, Methicillin-resistant Staphylococcus aureus (MRSA) plays a critical role due to its ability to acquire resistance against several antibiotics and play a role in the spread of diseases. Objectives: This research aimed to investigate the pattern of antibiotic resistance in MRSA isolates and perform molecular typing of MRSA isolates using various elements, including SCCmec type, ccr type, prophage type, and gene toxin profiles. Methods: The research spanned 20 months at Al-Zahra Hospital in Isfahan and involved 148 isolates from various anatomical sites. The isolates were evaluated for their antibiotic susceptibility patterns. They were characterized by screening for SCCmec typing, ccr typing, phage typing, and PCR profiling of pvl, hlb, sak, eta, and tst toxin genes. Results: From 148 total S. aureus isolates, 42% (n = 62) were methicillin-resistant. The MRSA isolates demonstrated substantial resistance to penicillin and ciprofloxacin, and 90.3% of MRSA isolates were multiple-drug resistant. Also, SCCmec types III, I, and IV were identified in 45.16%, 35.48%, and 19.35% of MRSA isolates, respectively. Also, seven prophage patterns and 15 toxin patterns were detected among MRSA isolates. Conclusions: Multi-drug resistance is common among MRSA isolates. The only effective drug among the investigated antibiotics was chloramphenicol. The MRSA isolates can be controlled by changing the prescribing procedure of antibiotics and applying infection control strategies. The studied MRSA isolates can cause a wide range of diseases due to having several bacteriophages that encode virulence factors. Identification of different types of prophages may be useful in predicting such pathogenic agents.
Analysis of Virulence Genes Among Methicillin Resistant Staphylococcus aureus (MRSA) Strains
Jundishapur Journal of Microbiology, 2014
Background: Staphylococcus aureus is amongst major human pathogens both in hospitals and the community. This bacterium is an opportunistic pathogen responsible for a large number of self-limiting and even life-threatening diseases in humans. Methicillin resistant S. aureus (MRSA) strains are common causes of emerging nosocomial infections and are considered as a major problem for public health. Objectives: We aimed to study the profile of some virulence genes including: sea, seb, sed, tst, eta, etb, LuKS/F-PV, hla and hld in methicillinresistant S. aureus by the PCR technique. Materials and Methods: A total of 345 isolates of S. aureus were collected from clinical specimens of patients referred to teaching hospitals of Shiraz; identification was done by biochemical (catalase, coagulase and DNase) and molecular tests. One hundred and forty six isolates of methicillin-resistant S. aureus (MRSA) were obtained and the presence of some toxin genes in these isolates was investigated by the polymerase chain reaction (PCR) technique. Results: The results showed that among the 345 isolates of S. aureus, 148 were confirmed as MRSA by screening with the cefoxitin disc diffusion (30 µg) method. Also among the 148 MRSA isolates, 146 isolates were confirmed as methicillin-resistant by molecular methods. The results showed that the frequency of methicillin-resistant and methicillin-sensitive S. aureus isolates during 2012 to 2013 in Namazi and Faghihi hospitals were 146 (42.3%) and 199 (57.7%), respectively. Besides, among the 146 confirmed MRSA isolates, 36.98% (54 isolates) and 63.02% (92 isolates) were related to female and male, respectively. The largest number of cases belonged to sputum samples (58 out of 146). The frequency of the eta, etb, sed, LuKS/F-PV, seb, tst, sea, hld and hla genes were 0.68%, 2.05%, 2.05%, 5.47%, 10.95%, 11.64%, 27.39%, 84.24% and 93.15%, respectively. In addition, amongst all examined genes, hla (93.15%) and eta (0.68%) genes had the highest and lowest frequencies, respectively. The greatest coexistence of genes was observed for the hla + hld gene combination (48.83%). The results of our study indicate that 98.63% of the isolates were positive for at least one of the virulence genes. Conclusions: The relative higher frequency of some virulence genes in this study may reflect the emergence of isolates containing these genes in Shiraz medical centers.
Antimicrobial Resistance and Infection Control, 2020
Background: The global spread of methicillin-resistant Staphylococcus aureus (MRSA) infections necessitates the use of validated methods for the identification and typing of this bacterium. This study aimed to determine the distribution of main molecular types of MRSA strain circulating among hospitalized patients in teaching hospitals in Isfahan and Kashan. Methods: A total of 146 Staphylococcus aureus strains were isolated from patients in four teaching hospitals in Isfahan and Kashan during June 2017 to September 2018. The antimicrobial resistance patterns of Staphylococcus aureus strains were performed by disc diffusion method. The MRSA strains were identified phenotypically and confirmed by PCR assay. The prevalence of microbial surface components recognizing adhesive matrix molecules (MSCRAMMs) genes among MRSA strains was evaluated by multiplex PCR. The genotypes of MRSA strains were determined by multilocus sequence typing and SCCmec typing. Results: Of 146 Staphylococcus aureus isolates, 24 (16.4%) isolates were identified as MRSA strains. According to antimicrobial susceptibility testing the highest resistance rates were seen for tetracycline, erythromycin, ciprofloxacin and gentamicin. All of Staphylococcus aureus isolates were susceptible to vancomycin whereas 3 (2.1%) isolates were resistant to linezolid. Three different SCCmec types were obtained among MRSA strains including 16 (66.7%) SCCmec type V, 3 (12.5%) SCCmec type III and 5 (20.8%) SCCmec type II. Of 24 MRSA isolates 20 (83.3%) carried MSCRAMMs genes including eno (70.8%), fib (54.1%), cna (25.0%), fnbB (16.6%), ebps 5 (20.8%), and the fnbA, bbp and clfA genes were not detected in any MRSA isolate. MLST analysis revealed 11 sequence types among MRSA isolates as follows:
Clinical Microbiology and Infection, 2006
in a tertiary-care university hospital in Guadalajara, Mexico, were characterised by antibiotype, pulsed-field gel electrophoresis (PFGE) of SmaI macrorestriction fragments, and hybridisation of ClaI digests with mecA-and Tn554-specific DNA probes. Representatives of the single clonal type found were analysed by spa typing, multilocus sequence typing and staphylococcal chromosomal cassette mec (SCCmec) typing, and were tested for the presence of 22 virulence determinants and agr type. A single PFGE pattern was identified, with minor variations over time, with spa type 2, sequence type 5, SCCmec type II, agr type 2 and the presence of the enterotoxin genes seg and sei, the c-haemolysin variant gene hlg-v and the leukocidin lukE-lukD genes. In addition, the isolates showed antimicrobial resistance to b-lactams, macrolides, chloramphenicol and imipenem, and susceptibility to gentamicin, rifampicin, trimethoprim-sulphamethoxazole and vancomycin. Following its appearance in 1997, this clone spread within the hospital, and is now present in most of the hospital units and wards.
Avicenna Journal of Clinical Microbiology and Infection, 2014
Background: Methicillin-resistant Staphylococcus aureus (MRSA) is one the most important pathogens across the world, associated with increased mortality rate compared to other Staphylococcal species. Objectives: The present study aimed to investigate different virulence determinants among MRSA isolates from Ilam, Iran. Materials and Methods: Overall, 100 MRSA isolates were collected from selected hospitals of Ilam, Iran. Oxacillin screening test and molecular detection of mecA were carried out by polymerase chain reaction (PCR) to confirm the methicillin resistance. Presence of the virulence genes et A, B, tst, sea a, b, c, d and e were assessed using multiplex PCR. Results: All the tested isolates were susceptible to vancomycin, but resistant to penicillin (100%), erythromycin (31%), clindamycin (27%), ciprofloxacin (27%), gentamicin (21%), and amikacin (16%). The frequencies of antibiotic resistance and virulence genes were as follows: tst 46%, eta 1%, etb 3%, sea 41%, seb 2%, sec 14%, and see 31%. Conclusions: Results of the present study showed that the tst and sea genes had high frequencies among the MRSA isolates. The increased prevalence of MRSA isolates containing different virulence genes, probably accompanied by antimicrobial resistance, can complicate the therapy of MRSA isolates.
2020
Background: The global spread of methicillin-resistant Staphylococcus aureus (MRSA) infections necessitates the use of validated methods for the identification and typing of this bacterium. This study aimed to determine the distribution of main molecular types of MRSA strain circulating among hospitalized patients in teaching hospitals in Isfahan and Kashan. Methods: A total of 146 Staphylococcus aureus strains were isolated from patients in four teaching hospitals in Isfahan and Kashan during June 2017 to September 2018. The antibiotic resistance patterns of Staphylococcus aureus strains were performed by disc diffusion method. The MRSA strains were identified phenotypically and confirmed by PCR assay. The prevalence of microbial surface components recognizing adhesive matrix molecules (MSCRAMMs) genes among MRSA strains was evaluated by multiplex PCR. The genotypes of MRSA strains were determined by multi-locus sequence type and SCC mec typing. Results: Of 146 Staphylococcus aureus isolates 24 (16.4%) isolates identified as MRSA strains. According to antibiotic susceptibility testing the highest resistance rates were seen to erythromycin, cefoxitin and clindamycin. All of Staphylococcus aureus isolates were sensitive to vancomycin whereas 3 (2.1%) isolates were resistant to linezolid. Three different SCC mec types were obtained among MRSA strains including 16 (66.7%) SCC mec type V, 3 (12.5%) SCC mec type III and 5 (20.8%) SCC mec type II. Of 24 MRSA isolates 20 (83.3%) carried MSCRAMMs genes including eno (70.8%), fib (54.1%) , cna (25.0%), fnbB (16.6%) , ebps 5 (20.8%), and fnbA , bbp and clfA genes were not detected. MLST analysis revealed 11 sequence types among MRSA isolates as follows:
Japanese journal of infectious diseases, 2012
Staphylococcus aureus is a persistent human pathogen responsible for a variety of infections ranging from soft-tissue infections to bacteremia. The objective of this study was to determine genetic relatedness between methicillin-resistant S. aureus (MRSA) and methicillin-susceptible S. aureus (MSSA) strains. We isolated 35 MRSA and 21 MSSA strains from sporadic cases at the main tertiary hospital in Terengganu, Malaysia, screening them for the presence of virulence genes. Their genetic relatedness was determined by accessory gene regulator (agr) types, PCR-restriction fragment length polymorphism (RFLP) of the coa gene, pulsed-field gel electrophoresis (PFGE), S. aureus protein A (spa), and multilocus-sequence typing (MLST). We found that 57z of MRSA and 43z of MSSA strains harbored enterotoxin genes. The majority (87.5z) of the strains were agr type I. PCR-RFLP and PFGE genotyping of the coa gene revealed that MRSA strains were genetically related, whereas MSSA strains had higher heterogeneity. The combined genotype, MLST-spa type ST239-t037, was shared amongMRSA and MSSA strains, indicating thatMRSA strains could have evolved from MSSA strains. Two combined MLST-spa types were present in MRSA strains, whereas 7 different MLST-spa types were detected in MSSA strains, including 2 combined types (ST779-t878 and ST1179-t267) that have not been reported in Malaysia. In conclusion, enterotoxin genes were more prevalent in MRSA than in MSSA strains in the Terengganu hospital. The MSSA strains were genetically more diverse than the MRSA strains.
Journal of Chemotherapy, 2016
Methicillin-resistant Staphylococcus aureus (MRSA) is one of the most important pathogens worldwide and compared to other staphylococcal species that are associated with higher mortality rate. A total of 500 Staphylococcus spp. was collected from selected hospitals in Ilam, Kermanshah, Khorram Abad and Hamadan cities and, via phenotypic and genotypic methods, was assessed to find MRSA. The presence or absence of prevalent antibiotic resistance genes and virulence genes was evaluated among MRSA isolates, using polymerase chain reaction (PCR) method, and then the SCCmec typing of these isolates was assayed by multiplex PCR. A total of 372 (74.4%) Stapylococcus spp. isolates were identified as S. aureus, among which 200 (53.8%) possessed the mecA gene and were distinguished as MRSA. All of MRSA isolates contained blaZ gene. The frequency of ermA and ermC genes among erythromycin-resistant MRSA isolates was 21.6% and 66.7%, respectively. The frequency of the virulence genes eta, hla and sea among MRSA isolates was 10%, 80.5% and 100%, respectively. SCCmec type IV accounted for 30.6% of the MRSA isolates and SCCmec type III, SCCmec type II and SCCmec type I accounted for 30%, 22% and 17.5% of the isolates, respectively. The antibiotic resistance genes and the virulence genes of blaZ, hla, sea, eta and ermC had high frequencies among the MRSA isolates. This study showed that the antibiotic resistance genes had higher frequencies among SCCmec types I and IV, which confirms the previous reports in this field.
Virulence Factors of Staphylococcus aureus Isolates in an Iranian Referral Children's Hospital
Objectives: The clinical importance of Staphylococcus aureus (S. aureus) is attributed to notable virulence factors, surface proteins, toxins, and enzymes as well as the rapid development of drug resistance. The aim of this study was to compare the occurrence of virulence factors produced by S. aureus strains isolated from children in an Iranian referral children's hospital. Methods: The presence of genes encoding for the enterotoxins A (sea), B (seb), C (sec), D (sed), TSST-1 (tsst), exfoliative toxin A (eta), and exfoliative toxin B (etb) were detected by Multiplex polymerase chain reaction (PCR) using specific primers. In addition, the standardized Kirby-Bauer disc-diffusion method was performed on Mueller-Hinton agar. Results: In total, 133 S. aureus isolates were obtained from different patients. Of these S. aureus isolates, 64 (48%) were methicillin-resistant S. aureus (MRSA), and all of these tested positive for the mecA gene. Regarding the classical enterotoxin genes, sea gene (40.6%) was the most prevalent followed by seb (19.6%), tsst (12.8%), eta (11.3%), etb (9%), sed (4.5%), and sec (3%). Among methicillin-susceptible S. aureus (MSSA) isolates, seb and tsst were the more prevalent toxins in comparison with MRSA isolates (p < 0.05), while the frequency of sea, sed, eta, and etb genes were higher among MRSA isolates (p > 0.05). Conclusion: In our study enterotoxin A was produced by 40.6% of the isolates (48% from MRSA and 33% from MSSA isolates) which was higher than in previous reports. According to our results, strict hygiene and preventative measures during food processing are highly recommended.