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Malachowa N, Sturdevant DE, Porter AR, Martin G, Martens C, Nair V, Hansen B, Ricklefs S, Jenkins SG, Chen L, Kreiswirth BN, DeLeo FR. Insights into the molecular basis of reduced vancomycin susceptibility among three prominent Staphylococcus aureus clonal complexes. Microbiol Spectr 2024:e0048624. [PMID: 38916317 DOI: 10.1128/spectrum.00486-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2024] [Accepted: 05/21/2024] [Indexed: 06/26/2024] Open
Abstract
Staphylococcus aureus is a leading cause of healthcare-associated infections globally. Vancomycin-resistant S. aureus (VRSA), those with high-level resistance [minimum inhibitory concentration (MIC) of 16-32 µg/mL vancomycin], are uncommon, whereas vancomycin-intermediate S. aureus (VISA; MIC of 4-8 µg/mL), are isolated more frequently and develop during long-term and/or repeated use of the antibiotic. VISA can be difficult to eradicate and infections may persist. Our knowledge of mechanisms that underlie the development of VISA is incomplete. We used a genomics approach to investigate the VISA phenotype in three prominent S. aureus lineages. All VISA clinical isolates tested had increased cell wall thickness compared with vancomycin-susceptible S. aureus strains. Growth rates of clonal complex (CC) 5, CC8, and CC45 clinical isolates were reduced in 2 µg/mL vancomycin compared to media alone. Culture in 2 and 4 µg/mL vancomycin sequentially for two weeks reduced susceptibility to daptomycin, televancin, tigecycline, and vancomycin in a majority of CC5, CC8, and CC45 isolates tested. We identified alleles reported previously to contribute to the VISA phenotype, but unexpectedly, these alleles were unique to each CC. A subtherapeutic concentration of vancomycin elicited changes in the VISA transcriptome-common and unique-among the three CCs tested. Multiple genes, including those encoding a glycerate kinase, an M50 family metallopeptidase, and an uncharacterized membrane protein, were upregulated among all three lineages and not reported previously as associated with VISA. Although there are lineage-specific changes in DNA sequence, our findings suggest changes in the VISA transcriptome constitute a general response to stress that confers reduced susceptibility to multiple antibiotics. IMPORTANCE Our understanding of the mechanisms that underlie the development of vancomycin-intermediate Staphylococcus aureus (VISA) is incomplete. To provide a more comprehensive view of this process, we compared genome sequences of clonal complex (CC) 5, CC8, and CC45 VISA clinical isolates and measured changes in the transcriptomes of these isolates during culture with a subtherapeutic concentration of vancomycin. Notably, we identified differentially expressed genes that were lineage-specific or common to the lineages tested, including genes that have not been previously reported to contribute to a VISA phenotype. Changes in gene expression were accompanied by reduced growth rate, increased cell wall thickness, and reduced susceptibility to daptomycin, televancin, tigecycline, and vancomycin. Our results provide support to the idea that changes in gene expression contribute to the development of VISA among three CCs that are a prominent cause of human infections.
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Affiliation(s)
- Natalia Malachowa
- Laboratory of Bacteriology, Rocky Mountain Laboratories, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, USA
| | - Daniel E Sturdevant
- Research Technologies Branch, Rocky Mountain Laboratories, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, USA
| | - Adeline R Porter
- Laboratory of Bacteriology, Rocky Mountain Laboratories, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, USA
| | - Grant Martin
- Laboratory of Bacteriology, Rocky Mountain Laboratories, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, USA
| | - Craig Martens
- Research Technologies Branch, Rocky Mountain Laboratories, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, USA
| | - Vinod Nair
- Research Technologies Branch, Rocky Mountain Laboratories, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, USA
| | - Bryan Hansen
- Research Technologies Branch, Rocky Mountain Laboratories, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, USA
| | - Stacy Ricklefs
- Research Technologies Branch, Rocky Mountain Laboratories, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, USA
| | - Stephen G Jenkins
- Pathology and Laboratory Medicine, Weill Cornell Medicine, New York, New York, USA
| | - Liang Chen
- Center for Discovery and Innovation, Hackensack Meridian Health, Nutley, New Jersey, USA
| | - Barry N Kreiswirth
- Center for Discovery and Innovation, Hackensack Meridian Health, Nutley, New Jersey, USA
| | - Frank R DeLeo
- Laboratory of Bacteriology, Rocky Mountain Laboratories, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, USA
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Montoya Urrego D, Vanegas JM, Jiménez JN. The remarkable genetic relationship between Staphylococcus aureus isolates from hemodialysis patients and their household contacts: Homes as an important source of colonization and dissemination. PLoS One 2022; 17:e0267276. [PMID: 35439257 PMCID: PMC9017883 DOI: 10.1371/journal.pone.0267276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Accepted: 04/05/2022] [Indexed: 11/18/2022] Open
Abstract
Introduction Staphylococcus aureus is a successful pathogen in hospital and community. Hemodialysis patients have high colonization rates. Interactions between them and their household contacts, are an opportunity to understand the S. aureus colonization between hospitals and community. This study aims to determine the clinical and epidemiological characteristics of S. aureus colonization in hemodialysis patients and their household contacts, as well as the genetic relationship between their isolates. Methods A cross-sectional study was conducted on hemodialysis patients from hospital-associated dialysis center in Medellín-Colombia, and their household contacts between 2019 and 2020. Colonization was assessed in the nostrils for household contacts and nostrils and skin around the catheter insertion for hemodialysis patients. Epidemiological information was obtained, and colonization was evaluated in their pets’ oral cavities. Bacterial identification and susceptibility were assessed using phenotypic and molecular methods. Molecular typing included SCCmec typing, pulsed-field gel electrophoresis (PFGE), spa typing, and virulence factor detection. Results Colonization frequency was 35.6% (n = 16/45) in patients (87.5% MSSA– 12.5% MRSA) and 43.1% (n = 53/123) in household contacts (88.7% MSSA—11.3% MRSA). Of 45 homes, 77.8% presented colonized people. Colonization was detected in at least two household members in 46.7% of homes, of which 52.4% had a genetic relationship. Colonization was 16% (n = 4/25) in pets (75% MRSA—25% MSSA). The most frequent clonal complex was CC8 (15.6%), and the spa typing revealed high diversity. Conclusion This study shows a high frequency of colonization by S. aureus in both hemodialysis patients and their household contacts and a significant genetic relationship between their isolates. This demonstrates an exchange of this bacterium and that homes are an important source of colonization to patients, highlighting the need for prevention strategies outside the hospital to avoid future infections, and the importance of the populations with permanent transit between the two environments.
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Affiliation(s)
- Daniela Montoya Urrego
- Grupo de investigación en Microbiología Básica y aplicada (MICROBA), Escuela de Microbiología, Universidad de Antioquia, Medellín, Colombia
| | - Johanna M. Vanegas
- Grupo de investigación en Microbiología Básica y aplicada (MICROBA), Escuela de Microbiología, Universidad de Antioquia, Medellín, Colombia
- Grupo de investigación en Salud Pública, Escuela de Ciencias de la Salud, Universidad Pontificia Bolivariana, Medellín, Colombia
| | - J. Natalia Jiménez
- Grupo de investigación en Microbiología Básica y aplicada (MICROBA), Escuela de Microbiología, Universidad de Antioquia, Medellín, Colombia
- * E-mail:
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A Combined Phenotypic-Genotypic Predictive Algorithm for In Vitro Detection of Bicarbonate: β-Lactam Sensitization among Methicillin-Resistant Staphylococcus aureus (MRSA). Antibiotics (Basel) 2021; 10:antibiotics10091089. [PMID: 34572671 PMCID: PMC8469475 DOI: 10.3390/antibiotics10091089] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 08/24/2021] [Accepted: 08/30/2021] [Indexed: 11/16/2022] Open
Abstract
Antimicrobial susceptibility testing (AST) is routinely used to establish predictive antibiotic resistance metrics to guide the treatment of bacterial pathogens. Recently, a novel phenotype termed "bicarbonate (NaHCO3)-responsiveness" was identified in a relatively high frequency of clinical MRSA strains, wherein isolates demonstrate in vitro "susceptibility" to standard β-lactams (oxacillin [OXA]; cefazolin [CFZ]) in the presence of NaHCO3, and in vivo susceptibility to these β-lactams in experimental endocarditis models. We investigated whether a targeted phenotypic-genotypic screening of MRSA could rule in or rule out NaHCO3 susceptibility upfront. We studied 30 well-characterized clinical MRSA bloodstream isolates, including 15 MIC-susceptible to CFZ and OXA in NaHCO3-supplemented Mueller-Hinton Broth (MHB); and 15 MIC-resistant to both β-lactams in this media. Using a two-tiered strategy, isolates were first screened by standard disk diffusion for susceptibility to a combination of amoxicillin-clavulanate [AMC]. Isolates then underwent genomic sequence typing: MLST (clonal complex [CC]); agr; SCCmec; and mecA promoter and coding region. The combination of AMC disk susceptibility testing plus mecA and spa genotyping was able to predict MRSA strains that were more or less likely to be NaHCO3-responsive in vitro, with a high degree of sensitivity and specificity. Validation of this screening algorithm was performed in six strains from the overall cohort using an ex vivo model of endocarditis. This ex vivo model recapitulated the in vitro predictions of NaHCO3-responsiveness vs. nonresponsiveness above in five of the six strains.
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Choi SH, Dagher M, Ruffin F, Park LP, Sharma-Kuinkel BK, Souli M, Morse AM, Eichenberger EM, Hale L, Kohler C, Warren B, Hansen B, Medie FM, McIntyre LM, Fowler VG. Risk Factors for Recurrent Staphylococcus aureus Bacteremia. Clin Infect Dis 2021; 72:1891-1899. [PMID: 32564065 DOI: 10.1093/cid/ciaa801] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2019] [Accepted: 06/12/2020] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND To understand the clinical, bacterial, and host characteristics associated with recurrent Staphylococcus aureus bacteremia (R-SAB), patients with R-SAB were compared to contemporaneous patients with a single episode of SAB (S-SAB). METHODS All SAB isolates underwent spa genotyping. All isolates from R-SAB patients underwent pulsed-field gel electrophoresis (PFGE). PFGE-indistinguishable pairs from 40 patients underwent whole genome sequencing (WGS). Acute phase plasma from R-SAB and S-SAB patients was matched 1:1 for age, race, sex, and bacterial genotype, and underwent cytokine quantification using 25-analyte multiplex bead array. RESULTS R-SAB occurred in 69 (9.1%) of the 756 study patients. Of the 69 patients, 30 experienced relapse (43.5%) and 39 reinfection (56.5%). Age, race, hemodialysis dependence, presence of foreign body, methicillin-resistant Staphyloccus aureus, and persistent bacteremia were individually associated with likelihood of recurrence. Multivariate risk modeling revealed that black hemodialysis patients were nearly 2 times more likely (odds ratio [OR] = 9.652 [95% confidence interval [CI], 5.402-17.418]) than white hemodialysis patients (OR = 4.53 [95% CI, 1.696-10.879]) to experience R-SAB. WGS confirmed PFGE interpretations in all cases. Median RANTES (regulated on activation, normal T cell expressed and secreted) levels in acute phase plasma from the initial episode of SAB were higher in R-SAB than in matched S-SAB controls (P = .0053, false discovery rate < 0.10). CONCLUSION This study identified several risk factors for R-SAB. The largest risk for R-SAB is among black hemodialysis patients. Higher RANTES levels in R-SAB compared to matched controls warrants further study.
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Affiliation(s)
- Seong-Ho Choi
- Department of Medicine, Duke University Medical Center, Durham, North Carolina, USA.,Division of Infectious Diseases, Department of Internal Medicine, Chung-Ang University Hospital, Chung-Ang University College of Medicine, Seoul, South Korea
| | - Michael Dagher
- Department of Medicine, Duke University Medical Center, Durham, North Carolina, USA
| | - Felicia Ruffin
- Department of Medicine, Duke University Medical Center, Durham, North Carolina, USA
| | - Lawrence P Park
- Department of Medicine, Duke University Medical Center, Durham, North Carolina, USA.,Duke Global Health Institute, Duke University, Durham, North Carolina, USA
| | | | - Maria Souli
- Department of Medicine, Duke University Medical Center, Durham, North Carolina, USA.,Duke Clinical Research Institute, Durham, North Carolina, USA
| | - Alison M Morse
- Departments of Molecular Genetics and Microbiology, University of Florida, Gainesville, Florida, USA.,University of Florida Genetics Institute University of Florida, Gainesville Florida, USA
| | - Emily M Eichenberger
- Department of Medicine, Duke University Medical Center, Durham, North Carolina, USA
| | - Lauren Hale
- Department of Medicine, Duke University Medical Center, Durham, North Carolina, USA
| | - Celia Kohler
- Department of Medicine, Duke University Medical Center, Durham, North Carolina, USA
| | - Bobby Warren
- Department of Medicine, Duke University Medical Center, Durham, North Carolina, USA
| | - Brenda Hansen
- Department of Medicine, Duke University Medical Center, Durham, North Carolina, USA.,Pediatric Gastroenterology, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Felix Mba Medie
- Department of Medicine, Duke University Medical Center, Durham, North Carolina, USA
| | - Lauren M McIntyre
- Departments of Molecular Genetics and Microbiology, University of Florida, Gainesville, Florida, USA.,University of Florida Genetics Institute University of Florida, Gainesville Florida, USA
| | - Vance G Fowler
- Department of Medicine, Duke University Medical Center, Durham, North Carolina, USA.,Duke Clinical Research Institute, Durham, North Carolina, USA
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5
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Souli M, Ruffin F, Choi SH, Park LP, Gao S, Lent NC, Sharma-Kuinkel BK, Thaden JT, Maskarinec SA, Wanda L, Hill-Rorie J, Warren B, Hansen B, Fowler VG. Changing Characteristics of Staphylococcus aureus Bacteremia: Results From a 21-Year, Prospective, Longitudinal Study. Clin Infect Dis 2020; 69:1868-1877. [PMID: 31001618 DOI: 10.1093/cid/ciz112] [Citation(s) in RCA: 74] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Accepted: 02/21/2019] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND We conducted a longitudinal study to evaluate changes in the clinical presentation and epidemiology of Staphylococcus aureus bacteremia (SAB) in an academic, US medical center. METHODS Consecutive patients with monomicrobial SAB were enrolled from January 1995 to December 2015. Each person's initial bloodstream S. aureus isolate was genotyped using spa typing. Clonal complexes (CCs) were assigned using Ridom StaphType software. Changes over time in both the patient and bacterial characteristics were estimated with linear regression. Associations between genotypes or clinical characteristics and complications were estimated using multivariable regression models. RESULTS Among the 2348 eligible participants, 54.2% had an implantable, foreign body of some type. This proportion increased significantly during the 21-year study period, by 0.96% annually (P = .002), as did comorbid conditions and acquisition outside of the hospital. Rates of any metastatic complication also significantly increased, by 0.94% annually (P = .019). Among the corresponding bloodstream S. aureus isolates, spa-CC012 (multi-locus sequence type [MLST] CC30), -CC004 (MLST CC45), -CC189 (MLST CC1), and -CC084 (MLST CC15) all significantly declined during the study period, while spa-CC008 (MLST CC8) significantly increased. Patients with SAB due to spa-CC008 were significantly more likely to develop metastatic complications in general, and abscesses, septic emboli, and persistent bacteremia in particular. After adjusting for demographic, racial, and clinical variables, the USA300 variant of spa-CC008 was independently associated with metastatic complications (odds ratio 1.42; 95% confidence interval 1.02-1.99). CONCLUSIONS Systematic approaches for monitoring complications of SAB and genotyping the corresponding bloodstream isolates will help identify the emergence of hypervirulent clones and likely improve clinical management of this syndrome.
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Affiliation(s)
- Maria Souli
- Department of Medicine, Duke University Medical Center, North Carolina.,Duke Clinical Research Institute, Durham, North Carolina.,Fourth Department of Internal Medicine, National and Kapodistrian University of Athens School of Medicine, Greece
| | - Felicia Ruffin
- Department of Medicine, Duke University Medical Center, North Carolina
| | - Seong-Ho Choi
- Department of Medicine, Duke University Medical Center, North Carolina.,Department of Internal Medicine, Division of Infectious Diseases, Chung-Ang University College of Medicine, Seoul, South Korea
| | - Lawrence P Park
- Department of Medicine, Duke University Medical Center, North Carolina.,Duke Global Health Institute, Duke University, Durham, North Carolina
| | - Shengli Gao
- Department of Medicine, Duke University Medical Center, North Carolina.,The First People's Hospital of Wujiang District, Suzhou City, Jiangsu Province, China
| | | | | | - Joshua T Thaden
- Department of Medicine, Duke University Medical Center, North Carolina
| | | | - Lisa Wanda
- Department of Medicine, Duke University Medical Center, North Carolina.,School of Medicine, University of North Carolina, Chapel Hill
| | - Jonathan Hill-Rorie
- Department of Medicine, Duke University Medical Center, North Carolina.,Harvard T. H. Chan School of Public Health, Boston, Massachusetts
| | - Bobby Warren
- Department of Medicine, Duke University Medical Center, North Carolina
| | - Brenda Hansen
- Department of Medicine, Duke University Medical Center, North Carolina.,Pediatric Gastroenterology, University of North Carolina, Chapel Hill
| | - Vance G Fowler
- Department of Medicine, Duke University Medical Center, North Carolina.,Duke Clinical Research Institute, Durham, North Carolina
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6
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Vanegas JM, Salazar-Ospina L, Montoya-Urrego D, Builes J, Roncancio GE, Jiménez JN. High frequency of colonization by diverse clones of beta-lactam-resistant Gram-negative bacilli in haemodialysis: different sources of transmission outside the renal unit? J Med Microbiol 2020; 69:1132-1144. [PMID: 32812863 DOI: 10.1099/jmm.0.001244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Introduction. While colonization by Staphylococcus aureus in haemodialysis patients has been assessed, knowledge about colonization by beta-lactam-resistant Gram-negative bacilli is still limited.Aim. To describe clinical and molecular characteristics in haemodialysis patients colonized by S. aureus (MSSA-MRSA) and beta-lactam-resistant Gram-negative bacilli in an ambulatory renal unit.Methodology. The study included patients with central venous catheters in an outpatient haemodialysis facility in Medellín, Colombia (October 2017-October 2018). Swab specimens were collected from the nostrils and skin around vascular access to assess colonization by S. aureus (MSSA-MRSA). Stool samples were collected from each patient to evaluate beta-lactam-resistant Gram-negative bacilli colonization. Molecular typing included PFGE, multilocus sequence typing (MLST), spa typing and enterobacterial repetitive intergenic consensus-PCR (ERIC). Clinical information was obtained from medical records and personal interview.Results. A total of 210 patients were included in the study. S. aureus colonization was observed in 33.8 % (n=71) of the patients, 4.8 % (n=10) of which were colonized by methicillin-resistant S. aureus. Stool samples were collected from 165 patients and of these 41.2 % (n=68) and 11.5 % (n=19) were colonized by extended-spectrum-beta-lactamase-producing (ESBL) and carbapenem-resistant bacilli, respectively. Typing methods revealed high genetic diversity among S. aureus and ESBL-producing Gram-negative bacilli (ESBL-GNB). Antibiotic use and hospitalization in the previous 6 months were observed in more than half of the studied population.Conclusion. The high colonization by ESBL-GNB in haemodialysis patients shows evidence for the need for stronger surveillance, not only for S. aureus but also for multidrug-resistant bacilli in order to avoid their spread. Additionally, the high genetic diversity suggests other sources of transmission outside the renal unit instead of horizontal transmission between patients.
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Affiliation(s)
- Johanna M Vanegas
- Línea de Epidemiología Molecular Bacteriana, Grupo de Investigación en Microbiología Básica y Aplicada, Escuela de Microbiología, Universidad de Antioquia, Medellín, Colombia
| | - Lorena Salazar-Ospina
- Línea de Epidemiología Molecular Bacteriana, Grupo de Investigación en Microbiología Básica y Aplicada, Escuela de Microbiología, Universidad de Antioquia, Medellín, Colombia
| | - Daniela Montoya-Urrego
- Línea de Epidemiología Molecular Bacteriana, Grupo de Investigación en Microbiología Básica y Aplicada, Escuela de Microbiología, Universidad de Antioquia, Medellín, Colombia
| | - Julián Builes
- Departamento de Nefrología, Hospital San Vicente Fundación, Medellín, Colombia
| | - Gustavo E Roncancio
- Departamento de Enfermedades Infecciosas, Clínica CardioVID, Medellín, Colombia
- Línea de Epidemiología Molecular Bacteriana, Grupo de Investigación en Microbiología Básica y Aplicada, Escuela de Microbiología, Universidad de Antioquia, Medellín, Colombia
| | - J Natalia Jiménez
- Línea de Epidemiología Molecular Bacteriana, Grupo de Investigación en Microbiología Básica y Aplicada, Escuela de Microbiología, Universidad de Antioquia, Medellín, Colombia
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Prevalence, Antimicrobial Resistance Profiles, Virulence and Enterotoxins-Determinant Genes of MRSA Isolated from Subclinical Bovine Mastitis in Egypt. Pathogens 2020; 9:pathogens9050362. [PMID: 32397408 PMCID: PMC7281566 DOI: 10.3390/pathogens9050362] [Citation(s) in RCA: 66] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 05/04/2020] [Accepted: 05/07/2020] [Indexed: 11/17/2022] Open
Abstract
Subclinical mastitis caused by Staphylococcus aureus has worldwide public health significance. Here, we aimed to determine the prevalence of S. aureus, antimicrobial resistance profiles, and the virulence and enterotoxins determinant genes of MRSA strains that caused subclinical bovine mastitis. Milk samples were collected from 120 lactating animals (50 buffaloes and 70 dairy cattle) from different farms located in Ismailia Province (Egypt). The collected samples were investigated for subclinical mastitis using a California mastitis test. The total prevalence of S. aureus was 35.9% (84/234) with 36.3% (53/146) in cattle and 31% (31/88) in buffaloes. Antimicrobial susceptibility testing showed that 35.7% (30/84) of the isolated strains were resistant to cefoxitin, defined as methicillin-resistant S. aureus (MRSA), with 37.7% (20/53) in cattle and 32.2% (10/31) in buffaloes. Using PCR, 100% of the tested strains harbored coa and mecA genes, while 86.6% were positive for spa gene, with remarkable gene size polymorphism. Additionally, 10% of the tested strains contained the pvl gene. Further, using multiplex PCR, 26.6% of the tested samples had sea gene, two strains had sec gene and only one strain had sea and sec genes. The seb and sed genes were absent in the tested strains. In conclusion, mecA, coa and spa virulence genes were widely distributed in MRSA strains isolated from bovine milk, whereas the sea gene was the most predominant enterotoxin gene. Notably, this is the first report that emphasizes the prevalence of pvl gene of MRSA isolated from bovine milk in Egypt.
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Ersoy SC, Otmishi M, Milan VT, Li L, Pak Y, Mediavilla J, Chen L, Kreiswirth B, Chambers HF, Proctor RA, Xiong YQ, Fowler VG, Bayer AS. Scope and Predictive Genetic/Phenotypic Signatures of Bicarbonate (NaHCO 3) Responsiveness and β-Lactam Sensitization in Methicillin-Resistant Staphylococcus aureus. Antimicrob Agents Chemother 2020; 64:e02445-19. [PMID: 32041719 PMCID: PMC7179597 DOI: 10.1128/aac.02445-19] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Accepted: 01/30/2020] [Indexed: 12/17/2022] Open
Abstract
Addition of sodium bicarbonate (NaHCO3) to standard antimicrobial susceptibility testing medium reveals certain methicillin-resistant Staphylococcus aureus (MRSA) strains to be highly susceptible to β-lactams. We investigated the prevalence of this phenotype (NaHCO3 responsiveness) to two β-lactams among 58 clinical MRSA bloodstream isolates. Of note, ∼75% and ∼36% of isolates displayed the NaHCO3 responsiveness phenotype to cefazolin (CFZ) and oxacillin (OXA), respectively. Neither intrinsic β-lactam MICs in standard Mueller-Hinton broth (MHB) nor population analysis profiles were predictive of this phenotype. Several genotypic markers (clonal complex 8 [CC8]; agr I and spa t008) were associated with NaHCO3 responsiveness for OXA.
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Affiliation(s)
| | - Mariam Otmishi
- California State University Dominguez Hills, Carson, California, USA
| | | | - Liang Li
- The Lundquist Institute, Torrance, California, USA
| | - Youngju Pak
- The Lundquist Institute, Torrance, California, USA
| | | | - Liang Chen
- Meridian Health, Nutley, New Jersey, USA
| | | | | | - Richard A Proctor
- University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, USA
| | - Yan Q Xiong
- The Lundquist Institute, Torrance, California, USA
- Geffen School of Medicine at UCLA, Los Angeles, California, USA
| | - Vance G Fowler
- Duke University Medical Center, School of Medicine, Durham, North Carolina, USA
| | - Arnold S Bayer
- The Lundquist Institute, Torrance, California, USA
- Geffen School of Medicine at UCLA, Los Angeles, California, USA
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9
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Methicillin-resistant Staphylococcus aureus: an overview of basic and clinical research. Nat Rev Microbiol 2020; 17:203-218. [PMID: 30737488 DOI: 10.1038/s41579-018-0147-4] [Citation(s) in RCA: 878] [Impact Index Per Article: 219.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Methicillin-resistant Staphylococcus aureus (MRSA) is one of the most successful modern pathogens. The same organism that lives as a commensal and is transmitted in both health-care and community settings is also a leading cause of bacteraemia, endocarditis, skin and soft tissue infections, bone and joint infections and hospital-acquired infections. Genetically diverse, the epidemiology of MRSA is primarily characterized by the serial emergence of epidemic strains. Although its incidence has recently declined in some regions, MRSA still poses a formidable clinical threat, with persistently high morbidity and mortality. Successful treatment remains challenging and requires the evaluation of both novel antimicrobials and adjunctive aspects of care, such as infectious disease consultation, echocardiography and source control. In this Review, we provide an overview of basic and clinical MRSA research and summarize the expansive body of literature on the epidemiology, transmission, genetic diversity, evolution, surveillance and treatment of MRSA.
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10
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Scott WK, Medie FM, Ruffin F, Sharma-Kuinkel BK, Cyr DD, Guo S, Dykxhoorn DM, Skov RL, Bruun NE, Dahl A, Lerche CJ, Petersen A, Larsen AR, Lauridsen TK, Johansen HK, Ullum H, Sørensen E, Hassager C, Bundgaard H, Schønheyder HC, Torp-Pedersen C, Østergaard LB, Arpi M, Rosenvinge F, Erikstrup LT, Chehri M, Søgaard P, Andersen PS, Fowler VG. Human genetic variation in GLS2 is associated with development of complicated Staphylococcus aureus bacteremia. PLoS Genet 2018; 14:e1007667. [PMID: 30289878 PMCID: PMC6192642 DOI: 10.1371/journal.pgen.1007667] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Revised: 10/17/2018] [Accepted: 08/29/2018] [Indexed: 12/30/2022] Open
Abstract
The role of host genetic variation in the development of complicated Staphylococcus aureus bacteremia (SAB) is poorly understood. We used whole exome sequencing (WES) to examine the cumulative effect of coding variants in each gene on risk of complicated SAB in a discovery sample of 168 SAB cases (84 complicated and 84 uncomplicated, frequency matched by age, sex, and bacterial clonal complex [CC]), and then evaluated the most significantly associated genes in a replication sample of 240 SAB cases (122 complicated and 118 uncomplicated, frequency matched for age, sex, and CC) using targeted sequence capture. In the discovery sample, gene-based analysis using the SKAT-O program identified 334 genes associated with complicated SAB at p<3.5 x 10−3. These, along with eight biologically relevant candidate genes were examined in the replication sample. Gene-based analysis of the 342 genes in the replication sample using SKAT-O identified one gene, GLS2, significantly associated with complicated SAB (p = 1.2 x 10−4) after Bonferroni correction. In Firth-bias corrected logistic regression analysis of individual variants, the strongest association across all 10,931 variants in the replication sample was with rs2657878 in GLS2 (p = 5 x 10−4). This variant is strongly correlated with a missense variant (rs2657879, p = 4.4 x 10−3) in which the minor allele (associated here with complicated SAB) has been previously associated with lower plasma concentration of glutamine. In a microarray-based gene-expression analysis, individuals with SAB exhibited significantly lower expression levels of GLS2 than healthy controls. Similarly, Gls2 expression is lower in response to S. aureus exposure in mouse RAW 264.7 macrophage cells. Compared to wild-type cells, RAW 264.7 cells with Gls2 silenced by CRISPR-Cas9 genome editing have decreased IL1-β transcription and increased nitric oxide production after S. aureus exposure. GLS2 is an interesting candidate gene for complicated SAB due to its role in regulating glutamine metabolism, a key factor in leukocyte activation. Complications from bloodstream infection with Staphylococcus aureus (S. aureus) are important causes of hospitalization, significant illness, and death. The causes of these complications are not well understood, but likely involve genetic factors rendering people more susceptible to such infections, differences in the bacteria that cause the infection, and the interactions between them. We examined the parts of the human genome that code for proteins to find variations that were more common in people with complicated S. aureus bacteremia (SAB), and identified one gene, called GLS2, in which variation is more common in complicated SAB cases than uncomplicated cases. Expression of GLS2 is lower in people with SAB than controls and in mouse white blood cells exposed to S. aureus. GLS2 encodes a protein that regulates the metabolism of glutamine, a regulatory process that activates white blood cells. These cells are very important in the immune response to S. aureus infection, and therefore genetic variants that might influence their growth are important potential genetic risk factors for complicated SAB.
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Affiliation(s)
- William K. Scott
- John P. Hussman Institute for Human Genomics, Miller School of Medicine, University of Miami, Miami, FL, United States of America
- Dr. John T. Macdonald Foundation Department of Human Genetics, Miller School of Medicine, University of Miami, Miami, FL, United States of America
- * E-mail: (WKS); (PSA); (VGF)
| | - Felix Mba Medie
- Department of Medicine, Division of Infectious Diseases, Duke University Medical Center, Durham, NC, United States of America
| | - Felicia Ruffin
- Department of Medicine, Division of Infectious Diseases, Duke University Medical Center, Durham, NC, United States of America
| | - Batu K. Sharma-Kuinkel
- Department of Medicine, Division of Infectious Diseases, Duke University Medical Center, Durham, NC, United States of America
| | - Derek D. Cyr
- Duke Clinical Research Institute, Duke University Medical Center, Durham, NC, United States of America
| | - Shengru Guo
- John P. Hussman Institute for Human Genomics, Miller School of Medicine, University of Miami, Miami, FL, United States of America
| | - Derek M. Dykxhoorn
- John P. Hussman Institute for Human Genomics, Miller School of Medicine, University of Miami, Miami, FL, United States of America
- Dr. John T. Macdonald Foundation Department of Human Genetics, Miller School of Medicine, University of Miami, Miami, FL, United States of America
| | - Robert L. Skov
- Department of Bacteria, Parasites, and Fungi, Statens Serum Institut, Copenhagen, Denmark
| | - Niels E. Bruun
- Department of Cardiology, Copenhagen University Hospital, Herlev-Gentofte, Denmark
- Department of Health Science and Technology, Aalborg University, Aalborg, Denmark
| | - Anders Dahl
- Department of Cardiology, Copenhagen University Hospital, Herlev-Gentofte, Denmark
| | - Christian J. Lerche
- Department of Clinical Microbiology, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
| | - Andreas Petersen
- Department of Bacteria, Parasites, and Fungi, Statens Serum Institut, Copenhagen, Denmark
| | - Anders Rhod Larsen
- Department of Bacteria, Parasites, and Fungi, Statens Serum Institut, Copenhagen, Denmark
| | | | - Helle Krogh Johansen
- Department of Clinical Microbiology, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
| | - Henrik Ullum
- Department of Clinical Medicine, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
| | - Erik Sørensen
- Department of Clinical Medicine, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
| | - Christian Hassager
- Department of Cardiology, Rigshospitalet and Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Henning Bundgaard
- Department of Cardiology, Rigshospitalet and Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Henrik C. Schønheyder
- Department of Clinical Microbiology, Aalborg University Hospital, Aalborg, Denmark
- Department of Clinical Medicine, Aalborg University, Aalborg, Denmark
| | | | - Louise Bruun Østergaard
- Department of Cardiology, Copenhagen University Hospital, Herlev-Gentofte, Denmark
- Clinical Institute, Aalborg University, Aalborg, Denmark
| | - Magnus Arpi
- Department of Clinical Microbiology, Copenhagen University Hospital, Herlev-Gentofte, Denmark
| | - Flemming Rosenvinge
- Department of Clinical Microbiology, Odense University Hospital, Odense, Denmark
| | - Lise T. Erikstrup
- Department of Clinical Microbiology, Aarhus University Hospital, Aarhus, Denmark
| | - Mahtab Chehri
- Department of Infectious Diseases, Copenhagen University Hospital, Hvidovre, Denmark
| | - Peter Søgaard
- Department of Cardiology, Aalborg University Hospital, Aalborg, Denmark
| | - Paal S. Andersen
- Department of Bacteria, Parasites, and Fungi, Statens Serum Institut, Copenhagen, Denmark
- Department of Veterinary and Animal Sciences, University of Copenhagen, Copenhagen, Denmark
- * E-mail: (WKS); (PSA); (VGF)
| | - Vance G. Fowler
- Department of Medicine, Division of Infectious Diseases, Duke University Medical Center, Durham, NC, United States of America
- Duke Clinical Research Institute, Duke University Medical Center, Durham, NC, United States of America
- * E-mail: (WKS); (PSA); (VGF)
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11
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Wang M, Zheng Y, Mediavilla JR, Chen L, Kreiswirth BN, Song Y, Yang R, Du H. Hospital Dissemination of tst-1-Positive Clonal Complex 5 (CC5) Methicillin-Resistant Staphylococcus aureus. Front Cell Infect Microbiol 2017; 7:101. [PMID: 28409124 PMCID: PMC5374150 DOI: 10.3389/fcimb.2017.00101] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2017] [Accepted: 03/14/2017] [Indexed: 01/12/2023] Open
Abstract
Methicillin-resistant Staphylococcus aureus (MRSA), is one of the most prevalent clinical pathogens isolated from hospital settings, and has increasingly identified in community settings. In China, the SCCmecIII-ST239 strains are disseminated in different geographic regions, accounting for >75% of all MRSA isolates in some national studies. Here we characterized 150 non-duplicate MRSA isolates collected from February 2012 to May 2013 in a tertiary hospital in Suzhou, Eastern China, to explore the molecular epidemiology. All isolates were characterized by spa typing, SCCmec typing, and detection of genes encoding Panton-Valentine leukocidin (PVL) and toxic shock syndrome toxin (TSST-1). Representative genotypes were also subjected to multilocus sequence typing (MLST). Antibiotic susceptibility testing was performed using BD Phoenix™ Automated Microbiology System. Molecular typing identified 11 clonal complex (CC) and 28 spa types, with the CC5-spa t002 (29.3%) and CC239-spa t037 (14.7%) being the most prevalent. SCCmec types II, III, IV, and V were identified in 33.3, 21.3, 23.3, and 21.3% of all isolates, respectively. PVL genes (lukF/S-PV) were detected in 11.3% of all isolates and from 6 CCs (5, 8, 59, 88, 239, and 398). The TSST-1 gene (tst) was detected in 18.0% of the all isolates, predominantly in CC5 (96.3%). All the tst-1-positve CC5 isolates were spa t002. Eighteen patients died within 30 days of hospitalization, and the in-hospital 30-day mortality was 12.0%. Multivariable analysis showed that 60 years old (odds ratio [OR] = 7.2, P = 0.026), cancer diagnosis (OR = 9.6, P = 0.022), and MRSA isolate carriage of tst-1 (OR = 62.5, P < 0.001) were independent factors associated with 30-day mortality. Our study revealed unique MRSA dissemination patterns in our hospital in comparison to those of other regions in China. The finding that tst-1-positive CC5 strains were associated with higher mortality highlights the need for strict infection control measures in order to prevent further spread of these strains in our hospital, as well as others.
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Affiliation(s)
- Min Wang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and EpidemiologyBeijing, China.,Clinical Laboratory, The Second Affiliated Hospital of Soochow UniversitySuzhou, China
| | - Yi Zheng
- Clinical Laboratory, The Second Affiliated Hospital of Soochow UniversitySuzhou, China
| | - Jose R Mediavilla
- New Jersey Medical School, Public Health Research Institute Tuberculosis Center, Rutgers UniversityNewark, NJ, USA
| | - Liang Chen
- New Jersey Medical School, Public Health Research Institute Tuberculosis Center, Rutgers UniversityNewark, NJ, USA
| | - Barry N Kreiswirth
- New Jersey Medical School, Public Health Research Institute Tuberculosis Center, Rutgers UniversityNewark, NJ, USA
| | - Yajun Song
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and EpidemiologyBeijing, China
| | - Ruifu Yang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and EpidemiologyBeijing, China
| | - Hong Du
- Clinical Laboratory, The Second Affiliated Hospital of Soochow UniversitySuzhou, China
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12
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Targeting Alpha Toxin and ClfA with a Multimechanistic Monoclonal-Antibody-Based Approach for Prophylaxis of Serious Staphylococcus aureus Disease. mBio 2016; 7:mBio.00528-16. [PMID: 27353753 PMCID: PMC4937210 DOI: 10.1128/mbio.00528-16] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Staphylococcus aureus produces numerous virulence factors, each contributing different mechanisms to bacterial pathogenesis in a spectrum of diseases. Alpha toxin (AT), a cytolytic pore-forming toxin, plays a key role in skin and soft tissue infections and pneumonia, and a human anti-AT monoclonal antibody (MAb), MEDI4893*, has been shown to reduce disease severity in dermonecrosis and pneumonia infection models. However, interstrain diversity and the complex pathogenesis of S. aureus bloodstream infections suggests that MEDI4893* alone may not provide adequate protection against S. aureus sepsis. Clumping factor A (ClfA), a fibrinogen binding protein, is an important virulence factor facilitating S. aureus bloodstream infections. Herein, we report on the identification of a high-affinity anti-ClfA MAb, 11H10, that inhibits ClfA binding to fibrinogen, prevents bacterial agglutination in human plasma, and promotes opsonophagocytic bacterial killing (OPK). 11H10 prophylaxis reduced disease severity in a mouse bacteremia model and was dependent on Fc effector function and OPK. Additionally, prophylaxis with 11H10 in combination with MEDI4893* provided enhanced strain coverage in this model and increased survival compared to that obtained with the individual MAbs. The MAb combination also reduced disease severity in murine dermonecrosis and pneumonia models, with activity similar to that of MEDI4893* alone. These results indicate that an MAb combination targeting multiple virulence factors provides benefit over a single MAb neutralizing one virulence mechanism by providing improved efficacy, broader strain coverage, and protection against multiple infection pathologies. Alternative strategies to broad-spectrum antibiotics are required to combat the antibiotic resistance epidemic. Previous attempts at active or passive immunization against Staphylococcus aureus targeting single antigens have failed in clinical trials despite positive preclinical data. To provide broad disease and isolate coverage, an effective immunization strategy likely must target multiple virulence mechanisms of the pathogen. Herein, we tested a multimechanistic MAb combination targeting alpha toxin (AT) and clumping factor A (ClfA) that neutralizes AT-mediated cytotoxicity, blocks fibrinogen binding by ClfA, prevents bacterial agglutination, targets the bacteria for opsonophagocytic killing, and provides broad isolate coverage in a lethal-bacteremia model. Although each MAb alone was effective in bacteremia against some individual isolates, the MAb combination provided improved protection against other isolates. These results illustrate the importance of targeting multiple virulence mechanisms and highlight the potential for an MAb combination targeting AT and ClfA to effectively prevent S. aureus disease.
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13
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Qi R, Joo HS, Sharma-Kuinkel B, Berlon NR, Park L, Fu CL, Messina JA, Thaden JT, Yan Q, Ruffin F, Maskarinec S, Warren B, Chu VH, Fortes CQ, Giannitsioti E, Durante-Mangoni E, Kanafani ZA, Otto M, Fowler VG. Increased in vitro phenol-soluble modulin production is associated with soft tissue infection source in clinical isolates of methicillin-susceptible Staphylococcus aureus. J Infect 2016; 72:302-8. [PMID: 26778460 DOI: 10.1016/j.jinf.2015.11.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Revised: 11/12/2015] [Accepted: 11/14/2015] [Indexed: 12/21/2022]
Abstract
BACKGROUND Phenol-soluble modulins (PSM) are amphipathic proteins produced by Staphylococcus aureus that promote virulence, inflammatory response, and biofilm formation. We previously showed that MRSA isolates from soft tissue infection (SSTI) produced significantly higher levels of PSM than MRSA isolates from hospital-acquired pneumonia (HAP) or infective endocarditis (IE). In this investigation, we sought to validate this finding in methicillin-susceptible S. aureus (MSSA) isolates. METHODS MSSA isolates (n = 162) from patients with SSTI, HAP, and IE were matched 1:1:1 based on geographic origin of the infection to form 54 triplets (North America n = 27, Europe n = 25, Australia n = 2). All isolates underwent spa typing and were classified using eGenomics. In vitro PSM production was quantified by high-performance liquid chromatography/mass spectrometry. Fischer's Exact Test and the Kruskal-Wallis test were used for statistical analysis. RESULTS Spa1 was more common in SSTI (14.81% SSTI, 3.70% HAP, 1.85% IE) (p < 0.03). Spa2 was more common in HAP (0% SSTI, 12.96% HAP, 3.70% IE) (p < 0.01). Levels of PSMα1-4 all differed significantly among the three clinical groups, with SSTI isolates producing the highest levels and IE producing the lowest levels of PSMα1-4. Spa1 isolates produced significantly more delta-toxin (p < 0.03) than non-Spa1 isolates. No associations between PSM levels and clinical outcome of SSTI, HAP, or IE were identified. CONCLUSION Production of PSMα1-4 is highest in SSTI MSSA isolates, supporting the hypothesis that these peptides are important for SSTI pathogenesis. These findings are similar to those described in MRSA, and demonstrate that associations between PSM levels and type of infection are independent of the methicillin-resistance status of the isolate.
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Affiliation(s)
- Robert Qi
- Division of Infectious Diseases, Department of Medicine, Duke University Medical Center, Durham, NC, USA
| | - Hwang-Soo Joo
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Batu Sharma-Kuinkel
- Division of Infectious Diseases, Department of Medicine, Duke University Medical Center, Durham, NC, USA
| | - Nicholas R Berlon
- Division of Infectious Diseases, Department of Medicine, Duke University Medical Center, Durham, NC, USA
| | - Lawrence Park
- Division of Infectious Diseases, Department of Medicine, Duke University Medical Center, Durham, NC, USA
| | - Chih-Lung Fu
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Julia A Messina
- Division of Infectious Diseases, Department of Medicine, Duke University Medical Center, Durham, NC, USA; Duke Clinical Research Institute, Duke University Medical Center, Durham, NC, USA
| | - Joshua T Thaden
- Division of Infectious Diseases, Department of Medicine, Duke University Medical Center, Durham, NC, USA
| | - Qin Yan
- Division of Infectious Diseases, Department of Medicine, Duke University Medical Center, Durham, NC, USA
| | - Felicia Ruffin
- Division of Infectious Diseases, Department of Medicine, Duke University Medical Center, Durham, NC, USA
| | - Stacey Maskarinec
- Division of Infectious Diseases, Department of Medicine, Duke University Medical Center, Durham, NC, USA
| | - Bobby Warren
- Division of Infectious Diseases, Department of Medicine, Duke University Medical Center, Durham, NC, USA
| | - Vivian H Chu
- Division of Infectious Diseases, Department of Medicine, Duke University Medical Center, Durham, NC, USA
| | - Claudio Q Fortes
- Hospital Universitario Clementino Fraga Filho/UFRJ, Rio de Janeiro, Brazil
| | | | - Emanuele Durante-Mangoni
- Internal Medicine Section, Department of Cardiothoracic Sciences, and Division of Infectious and Transplant Medicine, Second University of Naples at Monaldi Hospital, Napoli, Italy
| | - Zeina A Kanafani
- Division of Infectious Diseases, Department of Internal Medicine, American University of Beirut Medical Center, Beirut, Lebanon
| | - Michael Otto
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Vance G Fowler
- Division of Infectious Diseases, Department of Medicine, Duke University Medical Center, Durham, NC, USA; Duke Clinical Research Institute, Duke University Medical Center, Durham, NC, USA.
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14
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Berlon NR, Qi R, Sharma-Kuinkel BK, Joo HS, Park LP, George D, Thaden JT, Messina JA, Maskarinec SA, Mueller-Premru M, Athan E, Tattevin P, Pericas JM, Woods CW, Otto M, Fowler VG. Clinical MRSA isolates from skin and soft tissue infections show increased in vitro production of phenol soluble modulins. J Infect 2015; 71:447-57. [PMID: 26079275 PMCID: PMC4816458 DOI: 10.1016/j.jinf.2015.06.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Revised: 06/05/2015] [Accepted: 06/08/2015] [Indexed: 10/23/2022]
Abstract
BACKGROUND Phenol-soluble modulins (PSMs) are amphipathic, pro-inflammatory proteins secreted by most Staphylococcus aureus isolates. This study tested the hypothesis that in vitro PSM production levels are associated with specific clinical phenotypes. METHODS 177 methicillin-resistant S. aureus (MRSA) isolates from infective endocarditis (IE), skin and soft tissue infection (SSTI), and hospital-acquired/ventilator-associated pneumonia (HAP) were matched by geographic origin, then genotyped using spa-typing. In vitro PSM production was measured by high performance liquid chromatography/mass spectrometry. Statistical analysis was performed using Chi-squared or Kruskal-Wallis tests as appropriate. RESULTS Spa type 1 was significantly more common in SSTI isolates (62.7% SSTI; 1.7% IE; 16.9% HAP; p < 0.0001) while HAP and IE isolates were more commonly spa type 2 (0% SSTI; 37.3% IE; 40.7% HAP; p < 0.0001). USA300 isolates produced the highest levels of PSMs in vitro. SSTI isolates produced significantly higher quantities of PSMα1-4, PSMβ1, and δ-toxin than other isolates (p < 0.001). These findings persisted when USA300 isolates were excluded from analysis. CONCLUSIONS Increased in vitro production of PSMs is associated with an SSTI clinical source. This significant association persisted after exclusion of USA300 genotype isolates from analysis, suggesting that PSMs play a particularly important role in the pathogenesis of SSTI as compared to other infection types.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | - Eugene Athan
- Barwon Health, Deakin University, VIC, Australia
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15
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Laham NA, Mediavilla JR, Chen L, Abdelateef N, Elamreen FA, Ginocchio CC, Pierard D, Becker K, Kreiswirth BN. MRSA clonal complex 22 strains harboring toxic shock syndrome toxin (TSST-1) are endemic in the primary hospital in Gaza, Palestine. PLoS One 2015; 10:e0120008. [PMID: 25781188 PMCID: PMC4364023 DOI: 10.1371/journal.pone.0120008] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Accepted: 01/19/2015] [Indexed: 01/09/2023] Open
Abstract
Background Methicillin-resistant Staphylococcus aureus (MRSA) is an important pathogen in both community and healthcare-related settings worldwide. Current knowledge regarding the epidemiology of S. aureus and MRSA in Gaza is based on a single community-based carriage study. Here we describe a cross-sectional analysis of 215 clinical isolates collected from Al-Shifa Hospital in Gaza during 2008 and 2012. Methods All isolates were characterized by spa typing, SCCmec typing, and detection of genes encoding Panton-Valentine leukocidin (PVL) and toxic shock syndrome toxin (TSST-1). Representative genotypes were also subjected to multilocus sequence typing (MLST). Antibiotic susceptibility testing was performed using VITEK2 and MicroScan. Results MRSA represented 56.3% of all S. aureus strains, and increased in frequency from 2008 (54.8%) to 2012 (58.4%). Aside from beta-lactams, resistance was observed to tetracycline, erythromycin, clindamycin, gentamicin, and fluoroquinolones. Molecular typing identified 35 spa types representing 17 MLST clonal complexes (CC), with spa 998 (Ridom t223, CC22) and spa 70 (Ridom t044, CC80) being the most prevalent. SCCmec types I, III, IV, V and VI were identified among MRSA isolates, while type II was not detected. PVL genes (lukF/S-PV) were detected in 40.0% of all isolates, while the TSST-1 gene (tst) was detected in 27.4% of all isolates, with surprisingly high frequency within CC22 (70.4%). Both PVL and TSST-1 genes were found in several isolates from 2012. Conclusions Molecular typing of clinical isolates from Gaza hospitals revealed unusually high prevalence of TSST-1 genes among CC22 MRSA, which is noteworthy given a recent community study describing widespread carriage of a CC22 MRSA clone known as the ‘Gaza strain’. While the latter did not address TSST-1, tst-positive spa 998 (Ridom t223) has been detected in several neighboring countries, and described as endemic in an Italian NICU, suggesting international spread of a ‘Middle Eastern variant’ of pandemic CC22 strain EMRSA-15.
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Affiliation(s)
- Nahed Al Laham
- Department of Laboratory Medicine, Al Azhar University-Gaza, Gaza Strip, Palestine
- Public Health Research Institute, Rutgers University, Newark, New Jersey, United States of America
| | - José R. Mediavilla
- Public Health Research Institute, Rutgers University, Newark, New Jersey, United States of America
| | - Liang Chen
- Public Health Research Institute, Rutgers University, Newark, New Jersey, United States of America
| | - Nahed Abdelateef
- The Central Laboratories, Ministry of Health, Gaza Strip, Palestine
| | | | - Christine C. Ginocchio
- Department of Pathology and Laboratory Medicine, North Shore-LIJ Health System, Lake Success, New York, United States of America
- Hofstra North Shore-LIJ School of Medicine, Hempstead, New York, United States of America
| | - Denis Pierard
- Institute of Medical Microbiology, University Hospital of Brussels, Brussels, Belgium
| | - Karsten Becker
- Institute of Medical Microbiology, University Hospital of Muenster, Muenster, Germany
| | - Barry N. Kreiswirth
- Public Health Research Institute, Rutgers University, Newark, New Jersey, United States of America
- * E-mail:
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16
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Molecular and clinical characteristics of hospital and community onset methicillin-resistant Staphylococcus aureus strains associated with bloodstream infections. J Clin Microbiol 2015; 53:1599-608. [PMID: 25740776 DOI: 10.1128/jcm.03147-14] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Accepted: 02/23/2015] [Indexed: 11/20/2022] Open
Abstract
Methicillin-resistant Staphylococcus aureus (MRSA) bloodstream infections (BSI) are classified epidemiologically as health care-associated hospital onset (HAHO)-, health care-associated community onset (HACO)-, or community-associated (CA)-MRSA. Clinical and molecular differences between HAHO- and HACO-MRSA BSI are not well known. Thus, we evaluated clinical and molecular characteristics of MRSA BSI to determine if distinct features are associated with HAHO- or HACO-MRSA strains. Molecular genotyping and medical record reviews were conducted on 282 MRSA BSI isolates from January 2007 to December 2009. MRSA classifications were 38% HAHO-, 54% HACO-, and 8% CA-MRSA. Comparing patients with HAHO-MRSA to those with HACO-MRSA, HAHO-MRSA patients had significantly higher rates of malignancy, surgery, recent invasive devices, and mortality and longer hospital stays. Patients with HACO-MRSA were more likely to have a history of renal failure, hemodialysis, residence in a long-term-care facility, long-term invasive devices, and higher rate of MRSA relapse. Distinct MRSA molecular strain differences also were seen between HAHO-MRSA (60% staphylococcal cassette chromosome mec type II [SCCmec II], 30% SCCmec III, and 9% SCCmec IV) and HACO-MRSA (47% SCCmec II, 35% SCCmec III, and 16% SCCmec IV) (P < 0.001). In summary, our study reveals significant clinical and molecular differences between patients with HAHO- and HACO-MRSA BSI. In order to decrease rates of MRSA infection, preventive efforts need to be directed toward patients in the community with health care-associated risk factors in addition to inpatient infection control.
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Rozemeijer W, Fink P, Rojas E, Jones CH, Pavliakova D, Giardina P, Murphy E, Liberator P, Jiang Q, Girgenti D, Peters RPH, Savelkoul PHM, Jansen KU, Anderson AS, Kluytmans J. Evaluation of approaches to monitor Staphylococcus aureus virulence factor expression during human disease. PLoS One 2015; 10:e0116945. [PMID: 25719409 PMCID: PMC4342157 DOI: 10.1371/journal.pone.0116945] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2014] [Accepted: 12/17/2014] [Indexed: 11/19/2022] Open
Abstract
Staphylococcus aureus is a versatile pathogen of medical significance, using multiple virulence factors to cause disease. A prophylactic S. aureus 4-antigen (SA4Ag) vaccine comprising capsular polysaccharide (types 5 and 8) conjugates, clumping factor A (ClfA) and manganese transporter C (MntC) is under development. This study was designed to characterize S. aureus isolates recovered from infected patients and also to investigate approaches for examining expression of S. aureus vaccine candidates and the host response during human infection. Confirmation of antigen expression in different disease states is important to support the inclusion of these antigens in a prophylactic vaccine. Hospitalized patients with diagnosed S. aureus wound (27) or bloodstream (24) infections were enrolled. Invasive and nasal carriage S. aureus isolates were recovered and characterized for genotypic diversity. S. aureus antigen expression was evaluated directly by real-time, quantitative, reverse-transcriptase PCR (qRT-PCR) analysis and indirectly by serology using a competitive Luminex immunoassay. Study isolates were genotypically diverse and all had the genes encoding the antigens present in the SA4Ag vaccine. S. aureus nasal carriage was detected in 55% of patients, and in those subjects 64% of the carriage isolates matched the invasive strain. In swab samples with detectable S. aureus triosephosphate isomerase housekeeping gene expression, RNA transcripts encoding the S. aureus virulence factors ClfA, MntC, and capsule polysaccharide were detected by qRT-PCR. Antigen expression was indirectly confirmed by increases in antibody titer during the course of infection from acute to convalescent phase. Demonstration of bacterial transcript expression together with immunological response to the SA4Ag antigens in a clinically relevant patient population provides support for inclusion of these antigens in a prophylactic vaccine.
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Affiliation(s)
| | - Pamela Fink
- Pfizer Vaccine Research and Development, Pearl River, New York, United States of America
| | - Eduardo Rojas
- Pfizer Vaccine Research and Development, Pearl River, New York, United States of America
| | - C. Hal Jones
- Pfizer Vaccine Research and Development, Pearl River, New York, United States of America
| | - Danka Pavliakova
- Pfizer Vaccine Research and Development, Pearl River, New York, United States of America
| | - Peter Giardina
- Pfizer Vaccine Research and Development, Pearl River, New York, United States of America
| | - Ellen Murphy
- Pfizer Vaccine Research and Development, Pearl River, New York, United States of America
| | - Paul Liberator
- Pfizer Vaccine Research and Development, Pearl River, New York, United States of America
| | - Qin Jiang
- Pfizer Vaccine Research and Development, Pearl River, New York, United States of America
| | - Douglas Girgenti
- Pfizer Vaccine Research and Development, Pearl River, New York, United States of America
| | | | | | - Kathrin U. Jansen
- Pfizer Vaccine Research and Development, Pearl River, New York, United States of America
| | - Annaliesa S. Anderson
- Pfizer Vaccine Research and Development, Pearl River, New York, United States of America
- * E-mail:
| | - Jan Kluytmans
- VU University Medical Center, Amsterdam, The Netherlands
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18
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Abdelhady W, Chen L, Bayer AS, Seidl K, Yeaman MR, Kreiswirth BN, Xiong YQ. Early agr activation correlates with vancomycin treatment failure in multi-clonotype MRSA endovascular infections. J Antimicrob Chemother 2015; 70:1443-52. [PMID: 25564565 DOI: 10.1093/jac/dku547] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Accepted: 12/03/2014] [Indexed: 02/04/2023] Open
Abstract
OBJECTIVES Persistent MRSA infections are especially relevant to endovascular infections and correlate with suboptimal outcomes. However, the virulence signatures of Staphylococcus aureus that drive such persistence outcomes are not well defined. In the current study, we investigated correlations between accessory gene regulator (agr) activation and the outcome of vancomycin treatment in an experimental model of infective endocarditis (IE) due to MRSA strains with different agr and clonal complex (CC) types. METHODS Twelve isolates with the four most common MRSA CC and agr types (CC5-agr II, CC8-agr I, CC30-agr III and CC45-agr I) were evaluated for heterogeneous vancomycin-intermediate S. aureus (hVISA), agr function, agrA and RNAIII transcription, agr locus sequences, virulence and response to vancomycin in the IE model. RESULTS Early agr RNAIII activation (beginning at 2 h of growth) in parallel with strong δ-haemolysin production correlated with persistent outcomes in the IE model following vancomycin therapy. Importantly, such treatment failures occurred across the range of CC/agr types studied. In addition, these MRSA strains: (i) were vancomycin susceptible in vitro; (ii) were not hVISA or vancomycin tolerant; and (iii) did not evolve hVISA phenotypes or perturbed δ-haemolysin activity in vivo following vancomycin therapy. Moreover, agr locus sequence analyses revealed no common point mutations that correlated with either temporal RNAIII transcription or vancomycin treatment outcomes, encompassing different CC and agr types. CONCLUSIONS These data suggest that temporal agr RNAIII activation and agr functional profiles may be useful biomarkers to predict the in vivo persistence of endovascular MRSA infections despite vancomycin therapy.
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Affiliation(s)
- Wessam Abdelhady
- Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, CA, USA
| | - Liang Chen
- Public Health Research Institute, NJMS-Rutgers University, Newark, NJ, USA
| | - Arnold S Bayer
- Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, CA, USA David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Kati Seidl
- University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Michael R Yeaman
- Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, CA, USA David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Barry N Kreiswirth
- Public Health Research Institute, NJMS-Rutgers University, Newark, NJ, USA
| | - Yan Q Xiong
- Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, CA, USA David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
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19
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Characterization of alpha-toxin hla gene variants, alpha-toxin expression levels, and levels of antibody to alpha-toxin in hemodialysis and postsurgical patients with Staphylococcus aureus bacteremia. J Clin Microbiol 2014; 53:227-36. [PMID: 25392350 DOI: 10.1128/jcm.02023-14] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Alpha-toxin is a major Staphylococcus aureus virulence factor. This study evaluated potential relationships between in vitro alpha-toxin expression of S. aureus bloodstream isolates, anti-alpha-toxin antibody in serum of patients with S. aureus bacteremia (SAB), and clinical outcomes in 100 hemodialysis and 100 postsurgical SAB patients. Isolates underwent spa typing and hla sequencing. Serum anti-alpha-toxin IgG and neutralizing antibody levels were measured by using an enzyme-linked immunosorbent assay and a red blood cell (RBC)-based hemolysis neutralization assay. Neutralization of alpha-toxin by an anti-alpha-toxin monoclonal antibody (MAb MEDI4893) was tested in an RBC-based lysis assay. Most isolates encoded hla (197/200; 98.5%) and expressed alpha-toxin (173/200; 86.5%). In vitro alpha-toxin levels were inversely associated with survival (cure, 2.19 μg/ml, versus failure, 1.09 μg/ml; P < 0.01). Both neutralizing (hemodialysis, 1.26 IU/ml, versus postsurgical, 0.95; P < 0.05) and IgG (hemodialysis, 1.94 IU/ml, versus postsurgical, 1.27; P < 0.05) antibody levels were higher in the hemodialysis population. Antibody levels were also significantly higher in patients infected with alpha-toxin-expressing S. aureus isolates (P < 0.05). Levels of both neutralizing antibodies and IgG were similar among patients who were cured and those not cured (failures). Sequence analysis of hla revealed 12 distinct hla genotypes, and all genotypic variants were susceptible to a neutralizing monoclonal antibody in clinical development (MEDI4893). These data demonstrate that alpha-toxin is highly conserved in clinical S. aureus isolates. Higher in vitro alpha-toxin levels were associated with a positive clinical outcome. Although patients infected with alpha-toxin-producing S. aureus exhibited higher anti-alpha-toxin antibody levels, these levels were not associated with a better clinical outcome in this study.
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20
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Differences in epidemiological and molecular characteristics of nasal colonization with Staphylococcus aureus (MSSA-MRSA) in children from a university hospital and day care centers. PLoS One 2014; 9:e101417. [PMID: 24987854 PMCID: PMC4079298 DOI: 10.1371/journal.pone.0101417] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Accepted: 06/06/2014] [Indexed: 11/19/2022] Open
Abstract
Background Clinical significance of Staphylococcus aureus colonization has been demonstrated in hospital settings; however, studies in the community have shown contrasting results regarding the relevance of colonization in infection by community-associated MRSA (CA-MRSA). In Colombia there are few studies on S. aureus colonization. The aim of this study was to determine the molecular and epidemiological characteristics of nasal colonization by S. aureus (MSSA-MRSA) in children from a university hospital and day care centers (DCCs) of Medellin, Colombia. Methods An observational cross-sectional study was conducted in 400 children (200 in each setting), aged 0 months to 5 years, during 2011. Samples were collected from each nostril and epidemiological information was obtained from the parents. Genotypic analysis included spa typing, PFGE, MLST, SCCmec typing, detection of genes for virulence factors and agr groups. Results Frequency of S. aureus colonization was 39.8% (n = 159) (hospital 44.5% and DCCs 35.0%) and by MRSA, 5.3% (n = 21) (hospital 7.0% and DCCs 3.5%). Most S. aureus colonized children were older than two years (p = 0.005), the majority of them boys (59.1%), shared a bedroom with a large number of people (p = 0.028), with history of β-Lactamase inhibitors usage (p = 0.020). MSSA strains presented the greatest genotypic diversity with 15 clonal complexes (CC). MRSA isolates presented 6 CC, most of them (47.6%) belonged to CC8-SCCmec IVc and were genetically related to previously reported infectious MRSA strains. Conclusion Differences in epidemiological and molecular characteristics between populations may be useful for the understanding of S. aureus nasal colonization dynamics and for the design of strategies to prevent S. aureus infection and dissemination. The finding of colonizing MRSA with similar molecular characteristics of those causing infection demonstrates the dissemination capacity of S. aureus and the risk of infection among the child population.
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21
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Nelson CL, Pelak K, Podgoreanu MV, Ahn SH, Scott WK, Allen AS, Cowell LG, Rude TH, Zhang Y, Tong A, Ruffin F, Sharma-Kuinkel BK, Fowler VG. A genome-wide association study of variants associated with acquisition of Staphylococcus aureus bacteremia in a healthcare setting. BMC Infect Dis 2014; 14:83. [PMID: 24524581 PMCID: PMC3928605 DOI: 10.1186/1471-2334-14-83] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2013] [Accepted: 02/06/2014] [Indexed: 01/10/2023] Open
Abstract
Background Humans vary in their susceptibility to acquiring Staphylococcus aureus infection, and research suggests that there is a genetic basis for this variability. Several recent genome-wide association studies (GWAS) have identified variants that may affect susceptibility to infectious diseases, demonstrating the potential value of GWAS in this arena. Methods We conducted a GWAS to identify common variants associated with acquisition of S. aureus bacteremia (SAB) resulting from healthcare contact. We performed a logistic regression analysis to compare patients with healthcare contact who developed SAB (361 cases) to patients with healthcare contact in the same hospital who did not develop SAB (699 controls), testing 542,410 SNPs and adjusting for age (by decade), sex, and 6 significant principal components from our EIGENSTRAT analysis. Additionally, we evaluated the joint effect of the host and pathogen genomes in association with severity of SAB infection via logistic regression, including an interaction of host SNP with bacterial genotype, and adjusting for age (by decade), sex, the 6 significant principal components, and dialysis status. Bonferroni corrections were applied in both analyses to control for multiple comparisons. Results Ours is the first study that has attempted to evaluate the entire human genome for variants potentially involved in the acquisition or severity of SAB. Although this study identified no common variant of large effect size to have genome-wide significance for association with either the risk of acquiring SAB or severity of SAB, the variant (rs2043436) most significantly associated with severity of infection is located in a biologically plausible candidate gene (CDON, a member of the immunoglobulin family) and may warrant further study. Conclusions The genetic architecture underlying SAB is likely to be complex. Future investigations using larger samples, narrowed phenotypes, and advances in both genotyping and analytical methodologies will be important tools for identifying causative variants for this common and serious cause of healthcare-associated infection.
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Affiliation(s)
- Charlotte L Nelson
- Duke Clinical Research Institute, Duke University Medical Center, 2400 Pratt Street, Room 0311 Terrace Level, Durham, NC 27705, USA.
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22
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Casey JA, Curriero FC, Cosgrove SE, Nachman KE, Schwartz BS. High-density livestock operations, crop field application of manure, and risk of community-associated methicillin-resistant Staphylococcus aureus infection in Pennsylvania. JAMA Intern Med 2013; 173:1980-90. [PMID: 24043228 PMCID: PMC4372690 DOI: 10.1001/jamainternmed.2013.10408] [Citation(s) in RCA: 116] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
IMPORTANCE Nearly 80% of antibiotics in the United States are sold for use in livestock feeds. The manure produced by these animals contains antibiotic-resistant bacteria, resistance genes, and antibiotics and is subsequently applied to crop fields, where it may put community members at risk for antibiotic-resistant infections. OBJECTIVE To assess the association between individual exposure to swine and dairy/veal industrial agriculture and risk of methicillin-resistant Staphylococcus aureus (MRSA) infection. DESIGN, SETTING, AND PARTICIPANTS A population-based, nested case-control study of primary care patients from a single health care system in Pennsylvania from 2005 to 2010. Incident MRSA cases were identified using electronic health records, classified as community-associated MRSA or health care-associated MRSA, and frequency matched to randomly selected controls and patients with skin and soft-tissue infection. Nutrient management plans were used to create 2 exposure variables: seasonal crop field manure application and number of livestock animals at the operation. In a substudy, we collected 200 isolates from patients stratified by location of diagnosis and proximity to livestock operations. MAIN OUTCOMES AND MEASURES Community-associated MRSA, health care-associated MRSA, and skin and soft-tissue infection status (with no history of MRSA) compared with controls. RESULTS From a total population of 446,480 patients, 1539 community-associated MRSA, 1335 health care-associated MRSA, 2895 skin and soft-tissue infection cases, and 2914 controls were included. After adjustment for MRSA risk factors, the highest quartile of swine crop field exposure was significantly associated with community-associated MRSA, health care-associated MRSA, and skin and soft-tissue infection case status (adjusted odds ratios, 1.38 [95% CI, 1.13-1.69], 1.30 [95% CI, 1.05-1.61], and 1.37 [95% CI, 1.18-1.60], respectively); and there was a trend of increasing odds across quartiles for each outcome (P ≤ .01 for trend in all comparisons). There were similar but weaker associations of swine operations with community-associated MRSA and skin and soft-tissue infection. Molecular testing of 200 isolates identified 31 unique spa types, none of which corresponded to CC398 (clonal complex 398), but some have been previously found in swine. CONCLUSIONS AND RELEVANCE Proximity to swine manure application to crop fields and livestock operations each was associated with MRSA and skin and soft-tissue infection. These findings contribute to the growing concern about the potential public health impacts of high-density livestock production.
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Affiliation(s)
- Joan A Casey
- Department of Environmental Health Sciences, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland2Johns Hopkins School of Medicine, Baltimore, Maryland
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23
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Kwak YG, Truong-Bolduc QC, Bin Kim H, Song KH, Kim ES, Hooper DC. Association of norB overexpression and fluoroquinolone resistance in clinical isolates of Staphylococcus aureus from Korea. J Antimicrob Chemother 2013; 68:2766-72. [PMID: 23928023 DOI: 10.1093/jac/dkt286] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
OBJECTIVES Although the prevalence of fluoroquinolone resistance among methicillin-resistant Staphylococcus aureus (MRSA) is known to be higher than in methicillin-susceptible S. aureus (MSSA), the reasons have never been identified. METHODS We randomly selected 115 isolates of S. aureus collected from 10 different hospitals in Korea between June 2009 and May 2011. To investigate the difference in fluoroquinolone resistance mechanisms between MRSA and MSSA, we evaluated gyrA and parC mutations and the relative expression of the multidrug efflux pump genes norA, norB and norC. RESULTS All 62 ciprofloxacin-resistant S. aureus had either gyrA or parC mutations. The S84L mutation of gyrA (59/62, 95.2%) and the S80F mutation of parC (61/62, 98.4%) were the most common. Fifty-eight (93.6%) strains had both the S84L mutation of gyrA and the S80F mutation of parC. Among the 115 isolates, norB overexpression was the most common, occurring in 49 (42.6%) strains. There were only two (1.7%) strains with norA overexpression and none with norC overexpression. Strains overexpressing norB were more common among ciprofloxacin-resistant S. aureus (33/62, 53.2%) than ciprofloxacin-susceptible S. aureus (16/53, 30.2%) (P = 0.013). When we analysed 62 ciprofloxacin-resistant S. aureus strains, those overexpressing norB were more common in ciprofloxacin-resistant MRSA (28/46, 60.9%) than in ciprofloxacin-resistant MSSA (5/16, 31.3%) (P = 0.041). CONCLUSIONS Increased expression of norB can be a factor that contributes to ciprofloxacin resistance in MRSA strains.
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Affiliation(s)
- Yee Gyung Kwak
- Division of Infectious Diseases, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
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Nasal Carriage of Epidemic Methicillin-Resistant Staphylococcus aureus 15 (EMRSA-15) Clone Observed in Three Chicago-Area Long-Term Care Facilities. Antimicrob Agents Chemother 2013; 57:4551-4553. [PMID: 23796939 DOI: 10.1128/aac.00528-13] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Accepted: 06/14/2013] [Indexed: 11/20/2022] Open
Abstract
The spread of pandemic methicillin-resistant Staphylococcus aureus (MRSA) clones such as USA300 and EMRSA-15 is a global health concern. As a part of a surveillance study of three long-term care facilities in the Greater Chicago area, phenotypic and molecular characterization of nasal MRSA isolates was performed. We report a cluster of pandemic EMRSA-15, an MRSA clone rarely reported from the United States, detected during this study.
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Wang SH, Khan Y, Hines L, Mediavilla JR, Zhang L, Chen L, Hoet A, Bannerman T, Pancholi P, Robinson DA, Kreiswirth BN, Stevenson KB. Methicillin-resistant Staphylococcus aureus sequence type 239-III, Ohio, USA, 2007-2009. Emerg Infect Dis 2013; 18:1557-65. [PMID: 23018025 PMCID: PMC3471631 DOI: 10.3201/eid1810.120468] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Identification of virulent strains emphasizes the need for molecular surveillance.
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Affiliation(s)
- Shu-Hua Wang
- Ohio State University Wexner Medical Center, Columbus, Ohio 43210, USA.
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Genetic variation among Panton-Valentine leukocidin-encoding bacteriophages in Staphylococcus aureus clonal complex 30 strains. J Clin Microbiol 2013; 51:914-9. [PMID: 23284024 DOI: 10.1128/jcm.03015-12] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Clonal complex 30 (CC30), one of the major Staphylococcus aureus lineages, has caused extensive hospital-acquired and community-acquired infections worldwide. Recent comparative genomics studies have demonstrated that three CC30 clones-phage type 80/81, Southwest Pacific (SWP), and contemporary EMRSA-16 associated (Con) strains-shared a recent common ancestor more than 100 years ago. Panton-Valentine leukocidin (PVL), a bacteriophage encoded toxin that has been epidemiologically linked with community-associated methicillin-resistant S. aureus (CA-MRSA), has frequently been identified in CC30 clones, although the pvl gene variation and distribution of PVL-encoding phages are poorly understood. We determined here the distribution of PVL phages, PVL gene sequences, and chromosomal phage insertion sites in 52 S. aureus CC30 PVL-harboring isolates, collected from four continents over a 75-year period. Our results indicate that PVL phages with icosahedral heads, including Φ108PVL and ΦPVL, were mainly associated with phage 80/81 strains, whereas phages with elongated heads were predominantly found in SWP (ΦSa2958 and ΦTCH60) and Con (ΦSa2USA) strains. Nine single-nucleotide polymorphisms were identified in the lukSF-PV gene, with six isolates harboring the R variant that has been previously associated with CA-MRSA strains. Interestingly, all six R variant strains belonged to the same Con CC30 clone and carried a ΦSa2USA-like phage. Similar chromosomal phage insertion sites were also identified in all 52 PVL-harboring CC30 strains. These analyses provide important insights into the microepidemiology of PVL-harboring CC30 strains, while the discovery of ΦSa2USA-associated R variant strains sheds further light on the evolution of PVL-positive CA-MRSA.
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CC8 MRSA strains harboring SCCmec type IVc are predominant in Colombian hospitals. PLoS One 2012; 7:e38576. [PMID: 22745670 PMCID: PMC3380008 DOI: 10.1371/journal.pone.0038576] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2012] [Accepted: 05/07/2012] [Indexed: 11/19/2022] Open
Abstract
Background Recent reports highlight the incursion of community-associated MRSA within healthcare settings. However, knowledge of this phenomenon remains limited in Latin America. The aim of this study was to evaluate the molecular epidemiology of MRSA in three tertiary-care hospitals in Medellín, Colombia. Methods An observational cross-sectional study was conducted from 2008–2010. MRSA infections were classified as either community-associated (CA-MRSA) or healthcare-associated (HA-MRSA), with HA-MRSA further classified as hospital-onset (HAHO-MRSA) or community-onset (HACO-MRSA) according to standard epidemiological definitions established by the U.S. Centers for Disease Control and Prevention (CDC). Genotypic analysis included SCCmec typing, spa typing, PFGE and MLST. Results Out of 538 total MRSA isolates, 68 (12.6%) were defined as CA-MRSA, 243 (45.2%) as HACO-MRSA and 227 (42.2%) as HAHO-MRSA. The majority harbored SCCmec type IVc (306, 58.7%), followed by SCCmec type I (174, 33.4%). The prevalence of type IVc among CA-, HACO- and HAHO-MRSA isolates was 92.4%, 65.1% and 43.6%, respectively. From 2008 to 2010, the prevalence of type IVc-bearing strains increased significantly, from 50.0% to 68.2% (p = 0.004). Strains harboring SCCmec IVc were mainly associated with spa types t1610, t008 and t024 (MLST clonal complex 8), while PFGE confirmed that the t008 and t1610 strains were closely related to the USA300-0114 CA-MRSA clone. Notably, strains belonging to these three spa types exhibited high levels of tetracycline resistance (45.9%). Conclusion CC8 MRSA strains harboring SCCmec type IVc are becoming predominant in Medellín hospitals, displacing previously reported CC5 HA-MRSA clones. Based on shared characteristics including SCCmec IVc, absence of the ACME element and tetracycline resistance, the USA300-related isolates in this study are most likely related to USA300-LV, the recently-described ‘Latin American variant’ of USA300.
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Ferreira JP, Anderson KL, Correa MT, Lyman R, Ruffin F, Reller LB, Fowler VG. Transmission of MRSA between companion animals and infected human patients presenting to outpatient medical care facilities. PLoS One 2011; 6:e26978. [PMID: 22102871 PMCID: PMC3213111 DOI: 10.1371/journal.pone.0026978] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2011] [Accepted: 10/07/2011] [Indexed: 11/18/2022] Open
Abstract
Methicillin-resistant Staphylococcus aureus (MRSA) is a significant pathogen in both human and veterinary medicine. The importance of companion animals as reservoirs of human infections is currently unknown. The companion animals of 49 MRSA-infected outpatients (cases) were screened for MRSA carriage, and their bacterial isolates were compared with those of the infected patients using Pulsed-Field Gel Electrophoresis (PFGE). Rates of MRSA among the companion animals of MRSA-infected patients were compared to rates of MRSA among companion animals of pet guardians attending a “veterinary wellness clinic” (controls). MRSA was isolated from at least one companion animal in 4/49 (8.2%) households of MRSA-infected outpatients vs. none of the pets of the 50 uninfected human controls. Using PFGE, patient-pets MRSA isolates were identical for three pairs and discordant for one pair (suggested MRSA inter-specie transmission p-value = 0.1175). These results suggest that companion animals of MRSA-infected patients can be culture-positive for MRSA, representing a potential source of infection or re-infection for humans. Further studies are required to better understand the epidemiology of MRSA human-animal inter-specie transmission.
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Affiliation(s)
- Jorge Pinto Ferreira
- Department of Population Health and Pathobiology-PHP, North Carolina State University-NCSU College of Veterinary Medicine, Raleigh, North Carolina, United States of America.
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Ugolotti E, Bandettini R, Marchese A, Gualco L, Vanni I, Borzi L, Di Marco E, Castagnola E, Melioli G, Biassoni R. Molecular characterization of hospital-acquired methicillin-resistant Staphylococcus aureus strains in pediatric outbreaks using variable tandem repeat analysis with spa and ClfB typing. Diagn Microbiol Infect Dis 2011; 69:213-7. [PMID: 21251569 DOI: 10.1016/j.diagmicrobio.2010.08.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2010] [Revised: 07/29/2010] [Accepted: 08/23/2010] [Indexed: 11/30/2022]
Abstract
To analyze 67 clinical methicillin-resistant Staphylococcus aureus (MRSA) isolated from pediatric hospital infections, we used multilocus variable-number tandem-repeat DNA sequence-based techniques, targeting the protein A polymorphic X region and the clumping factor B complete R domain. We define a "clfB similarity score" and then compare the double loci analysis of closely related MRSA isolates with pulsed-field gel electrophoresis (PFGE). We found an endemic clone (MLST-ST8, spa-t008, SCCmecIV, ClfB lineage 1) able to originate 3 possible outbreaks and a second clone (MLST-ST152, spa-t355, SCCmecV, ClfB lineage 4) responsible for limited cases of MRSA infections, indicating that the combination of spa and clfB-lineage typing is useful to trace MRSA pediatric outbreaks.
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Affiliation(s)
- Elisabetta Ugolotti
- Molecular Medicine, Deparment of Experimental Medicine Istituto Giannina Gaslini, Largo G. Gaslini 5, 16147 Genoa, Italy
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30
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Nienaber JJC, Sharma Kuinkel BK, Clarke-Pearson M, Lamlertthon S, Park L, Rude TH, Barriere S, Woods CW, Chu VH, Marín M, Bukovski S, Garcia P, Corey GR, Korman T, Doco-Lecompte T, Murdoch DR, Reller LB, Fowler VG. Methicillin-susceptible Staphylococcus aureus endocarditis isolates are associated with clonal complex 30 genotype and a distinct repertoire of enterotoxins and adhesins. J Infect Dis 2011; 204:704-13. [PMID: 21844296 DOI: 10.1093/infdis/jir389] [Citation(s) in RCA: 120] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
BACKGROUND Using multinational collections of methicillin-susceptible Staphylococcus aureus (MSSA) isolates from infective endocarditis (IE) and soft tissue infections (STIs), we sought to (1) validate the finding that S. aureus in clonal complex (CC) 30 is associated with hematogenous complications and (2) test the hypothesis that specific genetic characteristics in S. aureus are associated with infection severity. METHODS IE and STI isolates from 2 cohorts were frequency matched by geographic origin. Isolates underwent spa typing to infer CC and multiplex polymerase chain reaction for presence of virulence genes. RESULTS 114 isolate pairs were genotyped. IE isolates were more likely to be CC30 (19.5% vs 6.2%; P = .005) and to contain 3 adhesins (clfB, cna, map/eap; P < .0001 for all) and 5 enterotoxins (tst, sea, sed, see, and sei; P ≤ .005 for all). CC30 isolates were more likely to contain cna, tst, sea, see, seg, and chp (P < .05 for all). CONCLUSIONS MSSA IE isolates were significantly more likely to be CC30 and to possess a distinct repertoire of virulence genes than MSSA STI isolates from the same region. The genetic basis of this association requires further study.
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Affiliation(s)
- Juhsien J C Nienaber
- Duke University Medical Center Division of Infectious Diseases and International Health, Durham, North Carolina, USA
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Gill SR, McIntyre LM, Nelson CL, Remortel B, Rude T, Reller LB, Fowler VG. Potential associations between severity of infection and the presence of virulence-associated genes in clinical strains of Staphylococcus aureus. PLoS One 2011; 6:e18673. [PMID: 21541311 PMCID: PMC3082525 DOI: 10.1371/journal.pone.0018673] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2010] [Accepted: 03/15/2011] [Indexed: 01/31/2023] Open
Abstract
Background The clinical spectrum of Staphylococcus aureus infection ranges from asymptomatic nasal carriage to osteomyelitis, infective endocarditis (IE) and death. In this study, we evaluate potential association between the presence of specific genes in a collection of prospectively characterized S. aureus clinical isolates and clinical outcome. Methodology/Principal Findings Two hundred thirty-nine S. aureus isolates (121 methicillin-resistant S. aureus [MRSA] and 118 methicillin-susceptible S. aureus [MSSA]) were screened by array comparative genomic hybridization (aCGH) to identify genes implicated in complicated infections. After adjustment for multiple tests, 226 genes were significantly associated with severity of infection. Of these 226 genes, 185 were not in the SCCmec element. Within the 185 non-SCCmec genes, 171 were less common and 14 more common in the complicated infection group. Among the 41 genes in the SCCmec element, 37 were more common and 4 were less common in the complicated group. A total of 51 of the 2014 sequences evaluated, 14 non-SCCmec and 37 SCCmec, were identified as genes of interest. Conclusions/Significance Of the 171 genes less common in complicated infections, 152 are of unknown function and may contribute to attenuation of virulence. The 14 non-SCCmec genes more common in complicated infections include bacteriophage-encoded genes such as regulatory factors and autolysins with potential roles in tissue adhesion or biofilm formation.
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Affiliation(s)
- Steven R Gill
- Department of Oral Biology, University at Buffalo, Buffalo, New York, United States of America.
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Alexander EL, Morgan DJ, Kesh S, Weisenberg SA, Zaleskas JM, Kaltsas A, Chevalier JM, Silberzweig J, Barrón Y, Mediavilla JR, Kreiswirth BN, Rhee KY. Prevalence, persistence, and microbiology of Staphylococcus aureus nasal carriage among hemodialysis outpatients at a major New York Hospital. Diagn Microbiol Infect Dis 2011; 70:37-44. [PMID: 21334154 DOI: 10.1016/j.diagmicrobio.2010.12.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2010] [Revised: 11/20/2010] [Accepted: 12/04/2010] [Indexed: 10/18/2022]
Abstract
The study aimed to determine the natural history of Staphylococcus aureus nasal colonization in hemodialysis outpatients. Surveillance cultures were taken from patients presenting for hemodialysis or routine care to identify S. aureus nasal carriers. A prospective cohort study was performed to identify risks for persistent colonization. Detailed microbiologic and molecular studies of colonizing isolates were performed. Only 23/145 (15.9%) dialysis patients were persistently colonized, and only HIV-positive status was associated with persistence (P = 0.05). Prior hospitalization was the only risk factor for methicillin-resistant S. aureus carriage (OR 2.5, P = 0.03). In isolates from patients with ≤ 42 days of vancomycin exposure, vancomycin minimum bactericidal concentrations (MBCs) increased with duration of exposure. Among dialysis patients, S. aureus colonization was limited and transient; only HIV status was associated with persistence. Nevertheless, duration of vancomycin exposure was associated with increasing vancomycin MBCs. Vancomycin exposure in S. aureus carriers may be involved in increasing resistance.
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Affiliation(s)
- Elizabeth L Alexander
- Division of Infectious Diseases, Department of Medicine, Weill Cornell Medical College, New York, NY 10065, USA
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Identification of a novel transposon (Tn6072) and a truncated staphylococcal cassette chromosome mec element in methicillin-resistant Staphylococcus aureus ST239. Antimicrob Agents Chemother 2010; 54:3347-54. [PMID: 20479198 DOI: 10.1128/aac.00001-10] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A novel composite transposon (Tn6072) resembling staphylococcal cassette chromosome mercury (SCCHg) was identified in a collection of sequence type (ST) 239 methicillin (meticillin)-resistant Staphylococcus aureus (MRSA) isolates from Romanian hospitals. Tn6072 is homologous to the 5' region of SCCHg found in staphylococcal cassette chromosome mec (SCCmec) type III prototype strain 85/2082 but lacks the characteristic mer operon. SCCHg has previously been reported to integrate downstream of orfX, at the same chromosomal location as SCCmec. Tn6072, by contrast, is demarcated by two IS431 elements, flanked by 8-bp direct repeats, and inserted upstream of the origin of replication, within an open reading frame homologous to SAR2700 of S. aureus strain MRSA252. Analysis of a geographically and temporally diverse collection of 111 strains from the ST239 clonal group uncovered 11 additional strains harboring Tn6072, demonstrating a lineage-specific insertion pattern. Complete sequence analysis of the SCCmec regions of two representative Romanian strains (BK16704, BK16691) revealed two additional novel structures derived from a type III SCCmec background. BK16704 possesses an SCCmec 3A.1.4 structure, with an IS256 insertion downstream of the right chromosomal junction. In contrast, the SCCmec element of BK16691 is truncated downstream of the mec gene complex, with a 24-kb deletion encompassing the right chromosomal junction and an inverted downstream IS256 element. This structure, tentatively named "psiSCCmec16691," confers methicillin resistance but lacks most of the J1/J2 region, including the ccr gene complex. Taken together, these findings provide evidence for the continuing evolution of SCC elements, as well as the ST239 clonal group.
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Multiplex real-time PCR for rapid Staphylococcal cassette chromosome mec typing. J Clin Microbiol 2009; 47:3692-706. [PMID: 19726600 DOI: 10.1128/jcm.00766-09] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Rapid identification and typing of methicillin (meticillin)-resistant Staphylococcus aureus (MRSA) is important for understanding the molecular epidemiology and evolution of MRSA and offers many advantages for controlling transmission in both health care and community settings. We developed a rapid molecular beacon real-time PCR (MB-PCR) assay for staphylococcal cassette chromosome mec (SCCmec) typing. The design of this system is based on the established definition of SCCmec types, namely, the combination of the mec class complex with the ccr allotype. The assay consists of two multiplex panels, the combination of which results in two targets (mec class, ccr) for each SCCmec type. MB-PCR panel I targets mecA, ccrB2, mecI, and the DeltamecR1-IS1272 junction (mec class B); it can definitively identify SCCmec types II and IV. MB-PCR panel II detects ccrC, ccrB1, ccrB3, ccrB4, and the DeltamecR1-IS431 junction (mec class C2) and is therefore capable of identifying SCCmec types I, III, V, and VI in combination with panel I. The method can also detect the recently described novel SCCmec type VIII (ccrAB4 with mec class A). Our assay demonstrated 100% concordance when applied to 162 MRSA strains previously characterized by traditional SCCmec typing schemes. Four geographically and temporally diverse S. aureus collections were also successfully classified by our assay, along with 1,683 clinical isolates comprising both hospital- and community-associated MRSA and methicillin-susceptible S. aureus strains. As many as 96 isolates can be classified easily within 3 to 4 h, including DNA isolation, PCR cycling, and analysis. The assay is rapid, robust, sensitive, and cost-effective, allowing for high-throughput SCCmec typing of MRSA isolates.
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