Superantigen gene profiles and presence of exfoliative toxin genes in community-acquired meticillin-resistant Staphylococcus aureus isolated from Chinese children

2011 ◽  
Vol 60 (1) ◽  
pp. 35-45 ◽  
Author(s):  
Dejing Wu ◽  
Xiangmei Li ◽  
Yonghong Yang ◽  
Yaojie Zheng ◽  
Chuanqing Wang ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Genetic Background ◽  
Current Knowledge ◽  
Chinese Children ◽  
Toxin Gene ◽  
Virulence Determinants ◽  
Accessory Gene ◽  
Exfoliative Toxin ◽  
Toxin Genes ◽  
Gene Profiles

This study aimed to evaluate the distribution of superantigen gene profiles and the presence of exfoliative toxin genes in community-acquired meticillin-resistant Staphylococcus aureus (CA-MRSA) isolated from Chinese children, and simultaneously to assess virulence gene profiles and genetic background. Of the CA-MRSA isolates, 88.9 % (88/99) harboured toxin genes, with sek as the most frequent toxin gene (62.6 %), followed by seq (61.6 %), seb (60.6 %) and sea (35.4 %). The eta gene was detected only in one ST398-IVa-spa t034 strain. The sed and etd genes were not found in any of the isolates tested. A total of 38 virulence genotypes were observed, of which the genotype seb-sek-seq (27.3 %, 24/88) comprised the majority, followed by sea-seb-sek-seq (18.2 %, 16/88). The enterotoxin gene cluster including seg-sei-sem-sen-seo-seu predominated at a rate of 15.1 %. The relationship among toxin genotypes, toxin genes encoding profiles of mobile genetic elements and genetic background was analysed. Among 66 clonal complex (CC) 59 isolates, 87.9 % (58/66) were positive for toxin genes, and 75.8 % (50/66) harboured the toxin gene combination seb-sek-seq. Among seb-sek-seq-positive CC59 strains, 42.0 % (21/50) also carried the sea gene. CC59 corresponded exclusively to accessory gene regulator 1 (agr-1). The data presented here enhance our current knowledge on the virulence determinants of CA-MRSA.

scholarly journals Association between agr group, genetic background, virulence factors and disease types of Staphylococcus aureus isolated from Chinese children

2020 ◽  
Author(s):  
Yan Xu ◽  
Suyun Qian ◽  
Kaihu Yao ◽  
Fang Dong ◽  
Wenqi Song ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Genetic Background ◽  
Virulence Genes ◽  
Critical Role ◽  
Group Iv ◽  
Type I ◽  
Virulence Determinants ◽  
Accessory Gene ◽  
Group Iii ◽  
Group I

Abstract Background Staphylococcus aureus (S. aureus) accessory gene regulator (agr) system plays a critical role in staphylococcal pathogenesis. Our study aimed to investigate the relationship between agr group, the genetic background, virulence genes and disease types distribution of S. aureus isolated from different clinical sources among Chinese children.Methods S. aureus strains were isolated from Beijing Children’s hospital from October 2017 to October 2019. Isolates were typed by multilocus sequence typing (MLST), staphylococcal protein A (spa), agr, and staphylococcal cassette chromosome mec (SCCmec) typing (for methicillin-resistant S. aureus [MRSA] isolates). Furthermore, all isolates were tested for the presence of 19 selected virulence genes.Results A total of 191 non-repetitive S. aureus clinical isolates were collected and the agr type I was the most prevalent (84.8%). S. aureus isolates were divided into 33 sequence types (STs), 20 clonal complexes (CCs) and 59 spa types, ST59 (39.8%) and t437 (37.7%) were the predominant types. CC59, CC25, CC22, CC951, CC8, and CC398 isolates possessed agr group I; CC15 isolates harbored agr group II; CC30 strains were characterized as agr group III, and CC121 harbored agr group IV. Of the 19 virulence genes, the tst gene was more prevalent among agr group III compared to other groups (p = 0.006); eta and etb genes were more prevalent among agr group IV than other groups (p = 0.003 and 0.001, respectively); nearly all strains that harbored the lukS/F-PV gene (98.3%) belonged to agr group I (p = 0.004); the frequencies of bbp and ebpS genes belonged to agr group I were statistically lower than that of other groups (p < 0.001). Among 161 diagnoses, the frequency of strains from cellulitis patient harbored agr group III was higher than that of other groups (p = 0.046), and one strain isolated from staphylococcal scalded skin syndrome (SSSS) patient, which was identified as agr type IV (p = 0.021).Conclusions The results indicated that the S. aureus agr type was linked to the genetic background. Besides, a possible relationship between the agr group, several virulence determinants, and specific disease types was observed.

scholarly journals Nationwide epidemiological study revealed the dissemination of meticillin-resistant Staphylococcus aureus carrying a specific set of virulence-associated genes in Japanese hospitals

2009 ◽  
Vol 58 (10) ◽  
pp. 1329-1336 ◽  
Author(s):  
Teruko Ohkura ◽  
Keiko Yamada ◽  
Akira Okamoto ◽  
Hisashi Baba ◽  
Yasuyoshi Ike ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Toxin Gene ◽  
Type Ii ◽  
Pfge Analysis ◽  
Gene Profile ◽  
Specific Group ◽  
Toxin Genes ◽  
Gene Profiles ◽  
Mrsa Strains ◽  
Staphylococcal Cassette Chromosome

To study comprehensive toxin profiles and the chromosomal diversity of current Japanese hospital-associated meticillin-resistant Staphylococcus aureus (HA-MRSA) strains, we conducted PCR-based identification of 28 toxin genes, and staphylococcal cassette chromosome mec (SCCmec) typing and PFGE analysis of 208 MRSA strains isolated from 100 hospitals throughout Japan. Of the tested HA-MRSA strains, 80.3 % were tst-positive. The most frequent toxin gene profile was characterized by the carriage of 13 genes, tst, sec, seg, sei, sel, sem, sen, seo, lukED, hla, hlb, hld and hlg-2. Ninety of the 208 strains had this profile, which was named pattern A. Among the 118 non-pattern A strains, 100 had similar toxin gene profiles, the concordance rates to pattern A of which were more than 80 %. Consequently, 91.3 % of the examined HA-MRSA strains carried similar toxin profiles, although PFGE patterns showed a wide variation. These strains belonged to SCCmec type II, agr II and coagulase type II. We concluded that, unlike MRSA from many other countries, most of the Japanese HA-MRSA strains belonged to, or were related to, a specific group carrying the set of 13 toxin genes, irrespective of chromosomal diversity. In addition, among the 13 toxin genes, the coexistence rates of tst, sec and sel, and those of seg, sei, sem, sen and seo, were higher than for the other toxin genes. High coexistence rates of tst, sec and sel genes suggested the presence of the pathogenicity island SaPIn1 in these strains.

Genotypes, superantigen gene profiles, and presence of exfoliative toxin genes in clinical methicillin-susceptible Staphylococcus aureus isolates

2010 ◽  
Vol 66 (2) ◽  
pp. 222-224 ◽  
Author(s):  
Marijke J.C.A. van Trijp ◽  
Damian C. Melles ◽  
Susan V. Snijders ◽  
Heiman F.L. Wertheim ◽  
Henri A. Verbrugh ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Exfoliative Toxin ◽  
Toxin Genes ◽  
Gene Profiles

Characterization of Toxin Genes and Antimicrobial Susceptibility of Staphylococcus aureus from Retail Raw Chicken Meat

2018 ◽  
Vol 81 (4) ◽  
pp. 528-533 ◽  
Author(s):  
SUIXIA LI ◽  
PANPAN WANG ◽  
JIALIN ZHAO ◽  
LUHONG ZHOU ◽  
PENGFEI ZHANG ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Antimicrobial Resistance ◽  
Antimicrobial Susceptibility ◽  
Antimicrobial Agents ◽  
Health Hazard ◽  
Toxin Gene ◽  
Potential Health ◽  
Toxin Genes ◽  
Genes Encoding ◽  
Potential Health Hazard

ABSTRACTThe aim of this study was to investigate the toxin gene profile and antimicrobial resistance of Staphylococcus aureus isolates from raw chicken in the People's Republic of China. In total, 289 S. aureus isolates were characterized by antimicrobial susceptibility testing, and genes encoding enterotoxins, exfoliative toxins, Panton-Valentine leukocidin, and toxic shock syndrome toxin were revealed by PCR. Overall, 46.0% of the isolates were positive for one or more toxin genes. A high proportion of toxin genes were pvl (26.6%), followed by sej (12.5%), sea (9.0%), seh (8.3%), seb (6.9%), sec (6.9%), sed (4.8%), sei (3.1%), and see (2.4%). None of the isolates harbored seg, tsst-1, or exfoliative toxin genes. In total, 29 toxin gene profiles were obtained, and pvl (10.7%) was the most frequent genotype, followed by sea (5.9%), seb (4.8%), and sej (4.2%). Furthermore, 99.7% of the strains were resistant to at least one of the tested antimicrobial agents, and 87.2% of them displayed multidrug resistance. Resistance was most frequently observed to trimethoprim-sulfamethoxazole and erythromycin (86.2% for each), followed by tetracycline (69.9%), amoxicillin–clavulanic acid (45.0%), and ampicillin (42.6%). None of the strains were resistant to vancomycin. This study indicates that S. aureus isolates from raw chicken harbored multiple toxin genes and exhibited multiple antimicrobial resistance, which represents a potential health hazard for consumers.

scholarly journals Staphylococcus aureusClinical Isolates: Antibiotic Susceptibility, Molecular Characteristics, and Ability to Form Biofilm

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
N. Indrawattana ◽  
O. Sungkhachat ◽  
N. Sookrung ◽  
M. Chongsa-nguan ◽  
A. Tungtrongchitr ◽  
...  
Keyword(s):  
Early Recognition ◽  
Clinical Isolates ◽  
Resistant Bacteria ◽  
Molecular Characteristics ◽  
Toxin Gene ◽  
Accessory Gene ◽  
Toxin Genes ◽  
Accessory Gene Regulator ◽  
Periodic Monitoring ◽  
Group 2

Periodic monitoring ofStaphylococcus aureuscharacteristics in a locality is imperative as their drug-resistant variants cause treatment problem. In this study, antibiograms, prevalence of toxin genes (sea-see, seg-ser, seu, tsst-1, eta, etb, andetd), PFGE types, accessory gene regulator (agr) groups, and ability to form biofilm of 92S. aureusThailand clinical isolates were investigated. They were classified into 10 drug groups: groups 1–7 (56 isolates) were methicillin resistant (MRSA) and 8–10 (36 isolates) were methicillin sensitive (MSSA). One isolate did not have any toxin gene, 4 isolates carried one toxin gene (seq), and 87 isolates had two or more toxin genes. No isolate hadsee, etb, ortsst-1; six isolates hadetaoretd. Combinedseg-sei-sem-sen-seoof the highly prevalentegclocus was 26.1%. Theseb, sec, sel, seu, andetaassociated significantly with MSSA;sekwas more in MRSA. Thesek-seqassociation was 52.17% while combinedsed-sejwas not found. Twenty-three PFGE types were revealed, no association of toxin genes with PFGE types. All fouragrgroups were present;agrgroup 1 was predominant (58.70%) butagrgroup 2 strains carried more toxin genes and were more frequent toxin producers. Biofilm formation was found in 72.83% of the isolates but there was no association with antibiograms. This study provides insight information on molecular and phenotypic markers of ThailandS. aureusclinical isolates which should be useful for future active surveillance that aimed to control a spread of existing antimicrobial resistant bacteria and early recognition of a newly emerged variant.

scholarly journals Association Between the Methicillin Resistance of Staphylococcus aureus Isolated from Slaughter Poultry, Their Toxin Gene Profiles and Prophage Patterns

2018 ◽  
Vol 75 (10) ◽  
pp. 1256-1266 ◽  
Author(s):  
Agnieszka Marek ◽  
Ewelina Pyzik ◽  
Dagmara Stępień-Pyśniak ◽  
Renata Urban-Chmiel ◽  
Łukasz S. Jarosz
Keyword(s):  
Staphylococcus Aureus ◽  
Methicillin Resistance ◽  
Toxin Gene ◽  
Gene Profiles

scholarly journals Accessory gene regulator (agr) dysfunction was unusual in Staphylococcus aureus isolated from Chinese children

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Xin Yang ◽  
Fang Dong ◽  
Suyun Qian ◽  
Lijuan Wang ◽  
Yingchao Liu ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Chinese Children ◽  
Accessory Gene ◽  
Accessory Gene Regulator

Community- and Health Care-Associated Methicillin-Resistant Staphylococcus aureus Infection in Tehran, Iran: Comparison of drug resistance and virulence determinants

2020 ◽  
Vol 20 ◽  
Author(s):  
Davood Yadegarynia ◽  
Shabnam Tehrani ◽  
Maryam Nasiri
Keyword(s):  
Staphylococcus Aureus ◽  
Drug Resistance ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Drug Susceptibility ◽  
Drug Susceptibility Testing ◽  
Clinical Isolates ◽  
Virulence Determinants ◽  
Methicillin Resistant ◽  
Exfoliative Toxin ◽  
Toxic Shock Syndrome Toxin

Background: Methicillin-resistant Staphylococcus aureus (MRSA) can cause serious infections not only in hospitals but also in the community. The present study was aimed to characterize drug resistance and virulence determinants of community-associated (CA) MRSA isolate compared with healthcare-associated (HA) MRSA. Materials and Methods: A total of 44 patients with HA-MRSA and 11 patients with CA-MRSA infection (median age, 72 years) were included. The clinical isolates of MRSA were subjected to molecular analysis of virulence genes and drug susceptibility testing. Results: Panton-Valentine leucocidin (PVL) exotoxin and toxic shock syndrome toxin (TSST) genes were disproportionately distributed between CA- and HA-isolates. PVL genes were more likely to be found among CA-isolates (36.4%) than HAisolates (18.2). TSST genes were identified in only 2 CA-MRSA isolates tested (18.2%) compared with 9 HA-isolate (20.5%). Exfoliative toxin-b gene was negative in all isolates, however, one HA-isolate was positive for exfoliative toxin-a. mec-A gene was present in all clinical isolates. CA-isolates were more likely to be susceptible to trimethoprimsulfamethoxazole and vancomycin compared with HA-isolates. Vancomycin-intermediate resistance was found in 2 HAisolates. All clinical isolates were also resistant to clindamycin. Conclusions: CA- and HA- MRSA isolates are epidemiologically and microbiologically distinct. Thus, the strategies to prevent and treat these infections would be different. Patients with CA- and HA-MRSA infections should be treated effectively and receive follow-up evaluation to ensure resolution of their infection. Surveillance studies should be conducted to determine the extent of CA- and HA-MRSA dissemination in Iran.

Molecular detection of enterotoxigenic Staphylococcus aureus isolated from mutton marketed in retail outlets of Chennai, India

2017 ◽  
Author(s):  
S. Wilfred Ruban ◽  
R. Narendra Babu ◽  
J. J. Abraham Robinson ◽  
Senthil Kumar ◽  
JT.M. A.P. Kumarasamy ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Molecular Detection ◽  
Toxin Gene ◽  
Specific Marker ◽  
Enterotoxin Gene ◽  
Gene Profiles ◽  
Retail Outlets ◽  
Meat Samples ◽  
Species Specific ◽  
Six Genes

The present study was aimed at detection of enterotoxigenic S. aureus in mutton marketed in retail outlets of Chennai. A total of 120 meat samples were collected from across Chennai for isolation of S. aureus and it was observed that 66.28 per cent of the samples were contaminated with S. aureus. The S. aureus count in mutton samples ranged from 1.8 x 102 to 4.9 x 104 CFU/ g with an overall average of 1.30 x 104 CFU/ g. All the isolates presumptively identified as S. aureus biochemically, amplified 181 bp product specific for nuc gene by PCR, which is species specific marker for S. aureus. Enterotoxin gene profiles (multiplex PCR) results revealed that 70.17 percent of the isolates were enterotoxigenic carrying only six genes (seb, sed, seg, seh, sei and sej) either alone or in combination, whereas none of these isolates harbored sea, sec and see. It was clear that seb (72.5 %) was the predominant enterotoxin gene followed by seg and sei, seh, sej and sed. Six different toxin gene profiles were exhibited by different isolates and majority of the isolates (55 %) carried two or more genes as compared to only one toxin gene.

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