Carriage of virulence factors and molecular characteristics ofStaphylococcus aureusisolates associated with bloodstream, and skin and soft tissue infections in children

2012 ◽  
Vol 141 (10) ◽  
pp. 2158-2162 ◽  
Author(s):  
T. LI ◽  
X. YU ◽  
J. XIE ◽  
Y. XU ◽  
Y. SHANG ◽  
...  
Keyword(s):  
Soft Tissue ◽  
Virulence Genes ◽  
Virulence Gene ◽  
Bloodstream Infections ◽  
High Rate ◽  
Molecular Characteristics ◽  
Soft Tissue Infections ◽  
Virulence Determinants ◽  
Gene Profiles ◽  
Sequence Types

SUMMARYWe investigated the virulence gene carriage and molecular type characteristics ofStaphylococcus aureusisolates from bloodstream infections (BSIs) and skin and soft tissue infections (SSTIs) in children. A total of 71 isolates, 16 of which were methicillin-resistantS. aureus(MRSA), were investigated by PCR for virulence-associated gene profiles, sequence type andspatype. This revealed that 76·7% and 53·7% of the SSTI and BSI isolates, respectively, exhibited simultaneous carriage of ⩾10 virulence genes. Compared to BSI isolates, carriage rates forhla,hlb,cna,clfA,seb,secandpvlgenes were significantly higher in SSTI isolates. By contrast, carriage ofeta,etbandseawas significantly higher for BSI isolates. Thirty-four sequence types (STs) and 36spatypes were identified in the 71 isolates and included 14 novel STs and four novelspatypes. ST59-MRSA-IV/V-t437 was the most common clone in the MRSA isolates. We concluded that virulence determinants are widely distributed in isolates ofS. aureusstrains from children with BSIs and SSTIs, with an unexpectedly high rate in SSTI isolates. Future profiling ofS. aureusvirulence determinants may allow the prediction of severity and outcome for children with these infections.

scholarly journals Characterisation of community-acquired Staphylococcus aureus causing skin and soft tissue infections in a children's hospital in Shanghai, China

2019 ◽  
Vol 147 ◽  
Author(s):  
Xing Wang ◽  
Yanyun Shen ◽  
Weichun Huang ◽  
Yun Zhou
Keyword(s):  
Staphylococcus Aureus ◽  
Soft Tissue ◽  
Virulence Genes ◽  
Protein A ◽  
Molecular Characteristics ◽  
Staphylococcal Protein A ◽  
Soft Tissue Infections ◽  
Mrsa Strains ◽  
Panton Valentine Leukocidin ◽  
Common Sequence

Abstract Community-acquired Staphylococcus aureus is a major pathogen responsible for skin and soft tissue infections (SSTIs). This study aimed to investigate the prevalence and molecular characteristics of community-acquired S. aureus isolates recovered from paediatric patients with SSTIs in Shanghai, China. Between January 2015 and January 2018, 91 community-acquired S. aureus isolates were characterised by antibiotic susceptibility, multilocus sequence typing (ST), staphylococcal protein A gene (spa) type and virulence genes. Methicillin-resistant S. aureus (MRSA) strains were also characterised by staphylococcal cassette chromosome mec (SCCmec) type. Forty-one (45.1%) S. aureus isolates were MRSA. ST59 (33.0%, 30/91) was the most common sequence type, and t437 (18.7%, 17/91) was the most common spa type. SCCmec IV and V accounted for 61.0% and 34.1% of all MRSA isolates, respectively. Each isolate carried at least six virulence genes. The positive rates of Panton-Valentine leukocidin genes among all S. aureus, MRSA and methicillin-susceptible S. aureus isolates were 30.8% (28/91), 39.0% (16/41) and 24% (12/50), respectively. The prevalence of community-associated MRSA was surprisingly high among children with community-acquired SSTIs in Shanghai. ST59-t437 was the most prevalent community-acquired S. aureus clone causing SSTIs.

scholarly journals Molecular characteristics and virulence gene profiles of Staphylococcus aureus isolates in Hainan, China

2019 ◽  
Author(s):  
Xuehan Li ◽  
Kai Xu ◽  
Chenglin Li ◽  
Tao Huang ◽  
Yirong Li
Keyword(s):  
Staphylococcus Aureus ◽  
Antibiotic Resistance ◽  
Virulence Genes ◽  
Sccmec Type ◽  
Mainland China ◽  
Virulence Gene ◽  
Molecular Characteristics ◽  
Spa Typing ◽  
Gene Profiles ◽  
High Prevalence

Abstract Background: There have been no reports regarding the molecular characteristics, virulence features, and antibiotic resistance profiles of Staphylococcus aureus (S. aureus) from Hainan, the southernmost province of China. Methods: 227 S. aureus isolates, consisting of 76 methicillin-resistant S. aureus (MRSA) and 151 methicillin-susceptible S. aureus (MSSA), were collected in 2013-2014 and 2018-2019 in Hainan, and investigated for their molecular characteristics, virulence genes, and antibiotic resistance profiles. Results: Thirty-four sequence types (STs) and 79 spa types were identified based on multilocus sequence typing (MLST) and spa typing, respectively. ST398 (14.1%, 32/227) was found to be the most prevalent, and moreover, the prevalence of ST398-MSSA increased significantly from 2013-2014 (5.5%, 5/91) to 2018-2019 (18.4%, 25/136). Seventy-six MRSA isolates were subject to staphylococcus chromosomal cassette mec (SCCmec) typing. SCCmec-IVa was the predominant SCCmec type, and specifically ST45-SCCmec IVa, an infrequent type in mainland China, was predominant in S. aureus from Hainan. Eleven virulence genes, including the Panton-Valentine leukocidin (pvl) and eta, were determined, and the positive rates of eta and pvl were found to be 57.3% and 47.6%. Such high prevalence has never been seen in mainland China before.

Uncoupling between core genome and virulome in extraintestinal pathogenic Escherichia coli

2015 ◽  
Vol 61 (9) ◽  
pp. 647-652 ◽  
Author(s):  
Natalia Fernández-Romero ◽  
María Pilar Romero-Gómez ◽  
Marta Mora-Rillo ◽  
Jesús Rodríguez-Baño ◽  
Lorena López-Cerero ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Core Genome ◽  
Virulence Gene ◽  
Bloodstream Infections ◽  
Opportunistic Pathogens ◽  
Single Nucleotide ◽  
The Core ◽  
Gene Profiles ◽  
Pathogenic Escherichia Coli ◽  
Sequence Types

Extraintestinal pathogenic Escherichia coli (ExPEC) are among the most frequently isolated bacterial pathogens in hospitals. They are considered opportunistic pathogens and are found mostly in urinary and bloodstream infections. They are genetically diverse, and many studies have sought associations between genotypes or virulence genes and infection site, severity, or outcome, with varied, often contradictory, results. To understand these difficulties, we have analyzed the diversity patterns in the core genomes and virulomes of more than 500 ExPEC isolates from 5 different collections. The core genome was analyzed using a multilocus sequence type-based single-nucleotide polymorphism (SNP) pyrosequencing approach, while the virulence gene content (the virulome) was studied by polymerase chain reaction detection of 25 representative genes. SNP typing showed a similar population structure in the different collections: half of the isolates belong to a few sequence types (5 to 8), while the other half is composed of a large diversity of sequence types that are found once or twice. Sampling analysis by rarefaction plots of SNP profiles showed saturation curves indicative of a limited diversity. Contrary to this, the virulome shows an extremely high diversity, with almost as many gene profiles as isolates, and linear, nonsaturating, rarefaction plots, even within sequence types. These data show that genetic exchange rates are very heterogeneous along the chromosome, being much higher in the virulome fraction of the genome than in the core genome.

scholarly journals Selection, Recombination, and Virulence Gene Diversity among Group B Streptococcal Genotypes

2009 ◽  
Vol 191 (17) ◽  
pp. 5419-5427 ◽  
Author(s):  
A. Cody Springman ◽  
David W. Lacher ◽  
Guangxi Wu ◽  
Nicole Milton ◽  
Thomas S. Whittam ◽  
...  
Keyword(s):  
Virulence Genes ◽  
Fragment Length Polymorphism ◽  
Gene Diversity ◽  
Virulence Gene ◽  
Polymorphism Analysis ◽  
Neonatal Disease ◽  
Gene Profiles ◽  
Phylogenetic Lineages ◽  
Group B ◽  
Sequence Types

ABSTRACT Transmission of group B Streptococcus (GBS) from mothers to neonates during childbirth is a leading cause of neonatal sepsis and meningitis. Although subtyping tools have identified specific GBS phylogenetic lineages that are important in neonatal disease, little is known about the genetic diversity of these lineages or the roles that recombination and selection play in the generation of emergent genotypes. Here, we examined genetic variation, selection, and recombination in seven multilocus sequence typing (MLST) loci from 94 invasive, colonizing, and bovine strains representing 38 GBS sequence types and performed DNA sequencing and PCR-based restriction fragment length polymorphism analysis of several putative virulence genes to identify gene content differences between genotypes. Despite the low level of diversity in the MLST loci, a neighbor net analysis revealed a variable range of genetic exchange among the seven clonal complexes (CCs) identified, suggesting that recombination is partly responsible for the diversity observed between genotypes. Recombination is also important for several virulence genes, as some gene alleles had evidence for lateral gene exchange across divergent genotypes. The CC-17 lineage, which is associated with neonatal disease, is relatively homogeneous and therefore appears to have diverged independently with an exclusive set of virulence characteristics. These data suggest that different GBS genetic backgrounds have distinct virulence gene profiles that may be important for disease pathogenesis. Such profiles could be used as markers for the rapid detection of strains with an increased propensity to cause neonatal disease and may be considered useful vaccine targets.

scholarly journals Molecular characteristics and virulence gene profiles of Staphylococcus aureus isolates in Hainan, China

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Xuehan Li ◽  
Tao Huang ◽  
Kai Xu ◽  
Chenglin Li ◽  
Yirong Li
Keyword(s):  
Staphylococcus Aureus ◽  
Antibiotic Resistance ◽  
Resistance Genes ◽  
Virulence Genes ◽  
Mainland China ◽  
Geographical Location ◽  
Antibiotic Resistance Genes ◽  
Virulence Gene ◽  
Molecular Characteristics ◽  
Staphylococcal Protein A

Abstract Background There have been no reports regarding the molecular characteristics, virulence features, and antibiotic resistance profiles of Staphylococcus aureus (S. aureus) from Hainan, the southernmost province of China. Methods Two hundred twenty-seven S. aureus isolates, consisting of 76 methicillin-resistant S. aureus (MRSA) and 151 methicillin-susceptible S. aureus (MSSA), were collected in 2013–2014 and 2018–2019 in Hainan, and investigated for their molecular characteristics, virulence genes, antibiotic resistance profiles and main antibiotic resistance genes. Results Forty sequence types (STs) including three new STs (ST5489, ST5492 and ST5493), and 79 Staphylococcal protein A (spa) types were identified based on multilocus sequence typing (MLST) and spa typing, respectively. ST398 (14.1%, 32/227) was found to be the most prevalent, and the prevalence of ST398-MSSA increased significantly from 2013 to 2014 (5.5%, 5/91) to 2018–2019 (18.4%, 25/136). Seventy-six MRSA isolates were subject to staphylococcus chromosomal cassette mec (SCCmec) typing. SCCmec-IVa was the predominant SCCmec type, and specifically, ST45-SCCmec IVa, an infrequent type in mainland China, was predominant in S. aureus from Hainan. The antibiotic resistance profiles and antibiotic resistance genes of S. aureus show distinctive features in Hainan. The resistant rates of the MRSA isolates to a variety of antibiotics were significantly higher than those of the MSSA isolates. The predominant erythromycin and tetracycline resistance genes were ermC (90.1%, 100/111) and tetK (91.8%, 78/85), respectively. Eleven virulence genes, including the Panton-Valentine leukocidin (pvl) and eta, were determined, and the frequency of eta and pvl were found to be 57.3 and 47.6%. Such high prevalence has never been seen in mainland China before. Conclusion S. aureus isolates in Hainan have unique molecular characteristics, virulence gene and antibiotic resistance profiles, and main antibiotic resistance genes which may be associated with the special geographical location of Hainan and local trends in antibiotic use.

Detection of virulence genes of APEC (avian pathogenic Escherichia coli) isolated from poultry in Noakhali, Bangladesh

2021 ◽  
Vol 7 (1) ◽  
pp. 967-972
Author(s):  
Farzana Ehetasum Hossain ◽  
Saiful Islam ◽  
Md Aminul Islam ◽  
Shariful Islam ◽  
Firoz Ahmed
Keyword(s):  
Escherichia Coli ◽  
Virulence Genes ◽  
Virulence Gene ◽  
Economic Loss ◽  
Point Of View ◽  
Pcr Analysis ◽  
Avian Pathogenic Escherichia Coli ◽  
Gene Profiles ◽  
Pathogenic Escherichia Coli ◽  
Wide Range

Avian colibacillosis, caused by avian pathogenic Escherichia coli (APEC), is one of the major infectious diseases of poultry that bring about great economic loss for the Bangladesh poultry industry. The present study aimed to determine the virulence genes of avian pathogenic Escherichia coli (APEC) from cases of colibacillosis in poultry at the Noakhali district of Bangladesh. Currently, virulence-associated gene profiles of APEC isolates were investigated by polymerase chain reaction (PCR). A total of 24 (twenty-four) Escherichia coli isolates were collected and presumptively identified from 8 (eight) colibacillosis cases from 4 commercial broiler poultry farms (2 broilers per farm) in Noakhali, Bangladesh. The pathogenesis of Escherichia coli involves a wide range of different virulence genes. At this point, four virulence genes, iutA, hlyF, iroN, and iss were detected by PCR analysis. It has been observed that iutA, iss, hlyF, and iroN genes were found in 7(29.16%), 20(83.33%), 22(91.66%), and 24(100%) APEC isolates respectively. Furthermore, out of the twenty-four APEC isolates, six (25%) isolates had four virulence genes, fourteen (58.33%) isolates carried at least three virulence genes, three (12.5%) isolates carried two genes and one (4.16%) isolates had one virulence gene. Most importantly. six types of virulence gene profiles existed within the APEC isolates from which profile number 3 (hlyF, iroN, iss) having 13 (54.16%) isolates were predominant. The occurrence of APEC isolates of this region which is responsible for avian colibacillosis cases can be a matter of concern from the public health point of view. Future investigations will be able to utilize these virulence genes to identify APEC in Bangladesh helping in the diagnosis and prevention of colibacillosis in poultry. Bioresearch Commu. 7(1): 967-972, 2021 (January)

scholarly journals Molecular Characteristics of Streptococcus pyogenes Isolated From Chinese Children With Different Diseases

2021 ◽  
Vol 12 ◽  
Author(s):  
Dingle Yu ◽  
Yunmei Liang ◽  
Qinghua Lu ◽  
Qing Meng ◽  
Wenjian Wang ◽  
...  
Keyword(s):  
Gene Expression ◽  
Antibiotic Resistance ◽  
Streptococcus Pyogenes ◽  
Wide Spectrum ◽  
Expression Patterns ◽  
Virulence Gene ◽  
High Rate ◽  
Molecular Characteristics ◽  
Virulence Gene Expression ◽  
Obstructive Sleep

Streptococcus pyogenes is a bacterial pathogen that causes a wide spectrum of clinical diseases exclusively in humans. The distribution of emm type, antibiotic resistance and virulence gene expression for S. pyogenes varies temporally and geographically, resulting in distinct disease spectra. In this study, we analyzed antibiotic resistance and resistance gene expression patterns among S. pyogenes isolates from pediatric patients in China and investigated the relationship between virulence gene expression, emm type, and disease categories. Forty-two representative emm1.0 and emm12.0 strains (n = 20 and n = 22, respectively) isolated from patients with scarlet fever or obstructive sleep apnea-hypopnea syndrome were subjected to whole-genome sequencing and phylogenetic analysis. These strains were further analyzed for susceptibility to vancomycin. We found a high rate and degree of resistance to macrolides and tetracycline in these strains, which mainly expressed ermB and tetM. The disease category correlated with emm type but not superantigens. The distribution of vanuG and virulence genes were associated with emm type. Previously reported important prophages, such as φHKU16.vir, φHKU488.vir, Φ5005.1, Φ5005.2, and Φ5005.3 encoding streptococcal toxin, and integrative conjugative elements (ICEs) such as ICE-emm12 and ICE-HKU397 encoding macrolide and tetracycline resistance were found present amongst emm1 or emm12 clones from Shenzhen, China.

scholarly journals 289. Impact of Clinician Specialty on the Use of Oral Antibiotic Therapy for Definitive Treatment of Uncomplicated Bloodstream Infections

2020 ◽  
Vol 7 (Supplement_1) ◽  
pp. S144-S145
Author(s):  
Jasmine R Marcelin ◽  
Mackenzie R Keintz ◽  
Jihyun Ma ◽  
Erica J Stohs ◽  
Bryan Alexander ◽  
...  
Keyword(s):  
Social Media ◽  
Soft Tissue ◽  
Infectious Diseases ◽  
Antibiotic Therapy ◽  
Bloodstream Infections ◽  
Definitive Treatment ◽  
Oral Antibiotic ◽  
Soft Tissue Infections ◽  
Gram Positive ◽  
Oral Antibiotic Therapy

Abstract Background No established guidelines exist regarding the role of oral antibiotic therapy (OAT) to treat uncomplicated bloodstream infections (uBSIs) and practices may vary depending on clinician specialty and experience. Methods An IRB-exempt web-based survey was emailed to Nebraska Medicine clinicians caring for hospitalized patients, and widely disseminated using social media. The survey was open access and once disseminated on social media, it was impossible to ascertain the total number of individuals who received the survey. Chi-squared analysis for categorical data was conducted to evaluate the association between responses and demographic groups. Results Of 275 survey responses, 51% were via social media, and 94% originated in the United States. Two-thirds of respondents were physicians, 16% pharmacists, and infectious diseases clinicians (IDC) represented 71% of respondents. The syndromes where most were comfortable using OAT routinely for uBSI were urinary tract infection (92%), pneumonia (82%), pyelonephritis (82%), and skin/soft tissue infections (69%). IDC were more comfortable routinely using OAT to treat uBSIs associated with vertebral osteomyelitis and prosthetic joint infections than non-infectious diseases clinicians (NIDC), but NIDC were more likely to report comfort with routine use of OAT to treat uBSIs associated with meningitis and skin/soft tissue infections. IDC were more likely to report comfort with routine use of OAT for uBSIs due to Enterobacteriaceae and gram-positive anaerobes, while NIDC were more likely to be comfortable with routinely using OAT to treat uBSIs associated with S. aureus, coagulase-negative staphylococci and gram-positive bacilli. In one clinical vignette of S. aureus uBSI due to debrided abscess, 11% of IDC would be comfortable using OAT vs 28% of NIDC; IDC were more likely to report routinely repeating blood cultures (99% vs 83%, p< 0.05). Figure 1: Clinician comfort using oral antibiotic therapy to treat uncomplicated bacteremia due to specific syndromes Figure 2: Clinician comfort using oral antibiotic therapy to treat uncomplicated bacteremia due to specific organisms Conclusion Considerable variation in comfort using OAT for uBSIs among IDC vs NIDC exists, highlighting opportunities for IDC to continue to demonstrate their value in clinical practice. Understanding the reasons for variability may be helpful in creating best practice guidelines to standardize decision making. Disclosures All Authors: No reported disclosures

scholarly journals Virulence gene profiles of avian pathogenic Escherichia coli isolated from chickens with colibacillosis in Bulawayo, Zimbabwe

2015 ◽  
Vol 82 (1) ◽  
Author(s):  
Joshua Mbanga ◽  
Yvonne O. Nyararai
Keyword(s):  
Escherichia Coli ◽  
Virulence Genes ◽  
Virulence Gene ◽  
Economic Losses ◽  
Avian Pathogenic Escherichia Coli ◽  
Pcr Assay ◽  
E Coli ◽  
Gene Profiles ◽  
Pathogenic Escherichia Coli ◽  
Polymerase Chain

Colibacillosis, a disease caused by avian pathogenic Escherichia coli (APEC), is one of the main causes of economic losses in the poultry industry worldwide. This study was carried out in order to determine the APEC-associated virulence genes contained by E. coli isolates causing colibacillosis in chickens. A total of 45 E. coli isolates were obtained from the diagnostics and research branch of the Central Veterinary Laboratories, Bulawayo, Zimbabwe. These isolates were obtained from chickens with confirmed cases of colibacillosis after postmortem examination. The presence of the iutA, hlyF, ompT, frz, sitD, fimH, kpsM, sitA, sopB, uvrY, pstB and vat genes were investigated by multiplex polymerase chain reaction (PCR) assay. Of the 45 isolates, 93% were positive for the presence of at least one virulence gene. The three most prevalent virulence genes were iutA (80%), fimH (33.3%) and hlyF (24.4%). The kpsM, pstB and ompT genes had the lowest prevalence, having been detected in only 2.2% of the isolates. All 12 virulence genes studied were detected in the 45 APEC isolates. Virulence gene profiles were constructed for each APEC isolate from the multiplex data. The APEC isolates were profiled as 62.2% fitting profile A, 31.1% profile B and 6.7% profile C. None of the isolates had more than seven virulence genes. Virulence profiles of Zimbabwean APEC isolates are different from those previously reported. Zimbabwean APEC isolates appear to be less pathogenic and may rely on environmental factors and stress in hosts to establish infection.

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