USA300 Methicillin-Resistant Staphylococcus aureus, United States, 2000-2013.
Ontology highlight
ABSTRACT:
SUBMITTER: Carrel M
PROVIDER: S-EPMC4622244 | biostudies-literature |
REPOSITORIES: biostudies-literature
Similar Datasets
Project description:USA300 methicillin-resistant Staphylococcus aureus (MRSA) isolates are usually resistant only to oxacillin, erythromycin, and, increasingly, levofloxacin. Of these, oxacillin and levofloxacin resistances are chromosomally encoded. Plasmid-mediated clindamycin, mupirocin, and/or tetracycline resistance has been observed among USA300 isolates, but these descriptions were limited to specific patient populations or isolated occurrences. We examined the antimicrobial susceptibilities of invasive MRSA isolates from a national surveillance population in order to identify USA300 isolates with unusual, possibly emerging, plasmid-mediated antimicrobial resistance. DNA from these isolates was assayed for the presence of resistance determinants and the presence of a pSK41-like conjugative plasmid. Of 823 USA300 isolates, 72 (9%) were tetracycline resistant; 69 of these were doxycycline susceptible and tetK positive, and 3 were doxycycline resistant and tetM positive. Fifty-one (6.2%) isolates were clindamycin resistant and ermC positive; 22 (2.7%) isolates were high-level mupirocin resistant (mupA positive); 5 (0.6%) isolates were trimethoprim-sulfamethoxazole (TMP-SMZ) resistant, of which 4 were dfrA positive; and 7 (0.9%) isolates were gentamicin resistant and aac6'-aph2'' positive. Isolates with pSK41-like plasmids (n = 24) were positive for mupA (n = 19), dfrA (n = 6), aac6'-aph2'' (n = 6), tetM (n = 2), and ermC (n = 8); 20 pSK41-positive isolates were positive for two or more resistance genes. Conjugative transfer of resistance was demonstrated between four gentamicin- and mupirocin-resistant and three gentamicin- and TMP-SMZ-resistant USA300 isolates; transconjugants harbored a single pSK41-like plasmid, which was PCR positive for aac6'-aph2'' and either mupA and/or dfrA. USA300 and USA100 isolates from the same state with identical resistance profiles contained pSK41-like plasmids with indistinguishable restriction and Southern blot profiles, suggesting horizontal plasmid transfer between USA100 and USA300 isolates.
| S-EPMC2934979 | biostudies-literature
Project description:BackgroundCommunity-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) is a significant bacterial pathogen that poses considerable clinical and public health challenges. The majority of the CA-MRSA disease burden consists of skin and soft tissue infections (SSTI) not associated with significant morbidity; however, CA-MRSA also causes severe, invasive infections resulting in significant morbidity and mortality. The broad range of disease severity may be influenced by bacterial genetic variation.ResultsWe sequenced the complete genomes of 36 CA-MRSA clinical isolates from the predominant North American community acquired clonal type USA300 (18 SSTI and 18 severe infection-associated isolates). While all 36 isolates shared remarkable genetic similarity, we found greater overall time-dependent sequence diversity among SSTI isolates. In addition, pathway analysis of non-synonymous variations revealed increased sequence diversity in the putative virulence genes of SSTI isolates.ConclusionsHere we report the first whole genome survey of diverse clinical isolates of the USA300 lineage and describe the evolution of the pathogen over time within a defined geographic area. The results demonstrate the close relatedness of clinically independent CA-MRSA isolates, which carry implications for understanding CA-MRSA epidemiology and combating its spread.
| S-EPMC3598774 | biostudies-literature
Project description:ImportanceEstimating the US burden of methicillin-resistant Staphylococcus aureus (MRSA) infections is important for planning and tracking success of prevention strategies.ObjectiveTo describe updated national estimates and characteristics of health care- and community-associated invasive methicillin-resistant Staphylococcus aureus (MRSA) infections in 2011.Design, setting, and participantsActive laboratory-based case finding identified MRSA cultures in 9 US metropolitan areas from 2005 through 2011. Invasive infections (MRSA cultured from normally sterile body sites) were classified as health care-associated community-onset (HACO) infections (cultured ≤ 3 days after admission and/or prior year dialysis, hospitalization, surgery, long-term care residence, or central vascular catheter presence ≤ 2 days before culture); hospital-onset infections (cultured >3 days after admission); or community-associated infections if no other criteria were met. National estimates were adjusted using US census and US Renal Data System data.Main outcomes and measuresNational estimates of invasive HACO, hospital-onset, and community-associated MRSA infections using US census and US Renal Data System data as the denominator.ResultsAn estimated 80,461 (95% CI, 69,515-93,914) invasive MRSA infections occurred nationally in 2011. Of these, 48,353 (95% CI, 40,195-58,642) were HACO infections; 14,156 (95% CI, 10,096-20,440) were hospital-onset infections; and 16,560 (95% CI, 12,806-21,811) were community-associated infections. Since 2005, adjusted national estimated incidence rates decreased among HACO infections by 27.7% and hospital-onset infections decreased by 54.2%; community-associated infections decreased by only 5.0%. Among recently hospitalized community-onset (nondialysis) infections, 64% occurred 3 months or less after discharge, and 32% of these were admitted from long-term care facilities.Conclusions and relevanceAn estimated 30,800 fewer invasive MRSA infections occurred in the United States in 2011 compared with 2005; in 2011 fewer infections occurred among patients during hospitalization than among persons in the community without recent health care exposures. Effective strategies for preventing infections outside acute care settings will have the greatest impact on further reducing invasive MRSA infections nationally.
| S-EPMC10887428 | biostudies-literature
Project description:In a community, it is unknown what factors account for transmission of methicillin-resistant Staphylococcus aureus (MRSA). We integrated whole genome sequencing (WGS) and epidemiologic data to identify factors associated with MRSA transmission networks in an urban community.WGS was performed on colonizing USA300 MRSA isolates from 74 individuals within 72 hours of admission to a public hospital in Chicago, IL. Single nucleotide variants (SNVs) were used to reconstruct the phylogeny of sequenced isolates, and epidemiologic data was overlaid to identify factors associated with transmission networks.The maximum within-patient SNV difference for an individual with multisite colonization was 41 SNVs, with no systematic divergence among body sites. We observed a minimum of 7 SNVs and maximum of 153 SNVs between isolates from different individuals. We identified 4 pairs of individuals whose isolates were within 40 SNVs of each other. Putting our isolates in the context of previously sequenced USA300 isolates from other communities, we identified a 13-member group and two 4-member groups that represent samples from putative local transmission networks. Individuals in these groups were more likely to be African American, to be human immunodeficiency virus-infected, to reside in high detainee release areas, and to be current users of illicit drugs.Using WGS, we observed potential transmission networks in an urban community and that certain epidemiologic factors were associated with inclusion in these networks. Future work with contact tracing and advanced molecular diagnostics may allow for identification of MRSA "epicenters" in the community where interventions can be targeted.
| S-EPMC4678108 | biostudies-literature
Project description:Methicillin-resistant Staphylococcus aureus (MRSA) USA300 isolates have been recognized globally, not only in community but also in healthcare settings. USA300 isolates were initially resistant only to methicillin, but resistance to non-?-lactams has emerged with time. To evaluate the prevalence and antimicrobial susceptibility of USA300 isolates in Stockholm, we conducted a nine-year retrospective study. Of 5359 consecutive MRSA cases in Stockholm, isolates from 285 cases were USA300 strains according to the pulsed-field gel electrophoresis pattern. Of these cases, repeated isolates with altered antibiotic resistance patterns were observed in six individuals. Therefore, antimicrobial susceptibility testing was performed on totally 291 isolates. To study the phylogenetic relatedness of isolates in transmission events and genomic resistance traits, 35 isolates were further studied by whole genome sequencing (WGS). The incidence of MRSA was increased from 17.6 per 100,000 inhabitants in 2008 to 37.3 per 100,000 inhabitants in 2016, while the proportion of USA300 cases declined from 6.6% in 2008 to 2.6% in 2016. Among the USA300 isolates, 73.5% were community-associated, 21.3% healthcare-associated, and 5.2% had unknown acquisition. The highest resistance rate among non-?-lactams was found in erythromycin (86%), followed by fluoroquinolones (68-69%). 57% of the isolates were resistant to both erythromycin and fluoroquinolone. Simultaneous resistance to four non-?-lactam antibiotic classes was found in six isolates. Four isolates were susceptible to all non-?-lactam antibiotics. Ceftaroline, daptomycin, linezolid, mupirocin, rifampicin, teicoplanin, telavancin, trimethoprim-sulfamethoxazole and vancomycin retained full activity in the study. WGS analysis indicated that isolates from an outbreak were phylogenetically closely related. In conclusion, USA300 MRSA isolates in Stockholm have neither been limited to the community setting, nor remained susceptible to non-?-lactam agents. WGS is becoming a useful tool in tracing transmission events. The results herein provide the most up-to-date and comprehensive information regarding status of USA300 strains in this geographic area.
| S-EPMC6221263 | biostudies-literature
Project description:Methicillin-resistant Staphylococcus aureus (MRSA) pulsed-field type (PFT) USA300 causes skin and soft tissue infections in military recruits and invasive disease in hospitals. Chlorhexidine gluconate (CHG) is used to reduce MRSA colonization and infection. The impact of CHG on the molecular epidemiology of MRSA is not known.To evaluate the impact of 2% CHG-impregnated cloths on the molecular epidemiology of MRSA colonization.Cluster-randomized, double-blind, controlled trial.Marine Officer Candidate School, Quantico, Virginia, in 2007.Military recruits.Thrice-weekly application of CHG-impregnated or control (Comfort Bath; Sage) cloths over the entire body.Baseline and serial (every 2 weeks) nasal and/or axillary swab samples were assessed for MRSA colonization. Molecular analysis was performed with pulsed-field gel electrophoresis.During training, 77 subjects (4.9%) acquired MRSA, 26 (3.3%) in the CHG group and 51 (6.5%) in the control group (P=.004). When analyzed for PFT, 24 subjects (3.1%) in the control group but only 6 subjects (0.8%) in the CHG group (P=.001) had USA300. Of the 167 colonizing isolates recovered from 77 subjects, 99 were recovered from the control group, including USA300 (40.4%), USA800 (38.4%), USA1000 (12.1%), and USA100 (6.1%), and 68 were recovered from the CHG group, including USA800 (51.5%), USA100 (23.5%), and USA300 (13.2%).CHG decreased the transmission of MRSA--more specifically, USA300--among military recruits. In addition, USA300 and USA800 outcompeted other MRSA PFTs at incident colonization. Future studies should evaluate the broad-based use of CHG to decrease transmission of USA300 in hospital settings.
| S-EPMC5824645 | biostudies-literature
Project description:BackgroundPrevious reports suggested that US methicillin-resistant Staphylococcus aureus (MRSA) strain epidemiology has changed since the rise of USA300 MRSA. We describe invasive MRSA trends by strain type.MethodsData came from 5 Centers for Disease Control and Prevention Emerging Infections Program sites conducting population-based surveillance and collecting isolates for invasive MRSA (ie, from normally sterile body sites), 2005-2013. MRSA bloodstream infection (BSI) incidence per 100 000 population was stratified by strain type and epidemiologic classification of healthcare exposures. Invasive USA100 vs USA300 case characteristics from 2013 were compared through logistic regression.ResultsFrom 2005 to 2013, USA100 incidence decreased most notably for hospital-onset (6.1 vs 0.9/100 000 persons, P < .0001) and healthcare-associated, community-onset (10.7 vs 4.9/100 000 persons, P < .0001) BSIs. USA300 incidence for hospital-onset BSIs also decreased (1.5 vs 0.6/100 000 persons, P < .0001). However, USA300 incidence did not significantly change for healthcare-associated, community-onset (3.9 vs 3.3/100 000 persons, P = .05) or community-associated BSIs (2.5 vs 2.4/100 000 persons, P = .19). Invasive MRSA was less likely to be USA300 in patients who were older (adjusted odds ratio [aOR], 0.97 per year [95% confidence interval {CI}, .96-.98]), previously hospitalized (aOR, 0.36 [95% CI, .24-.54]), or had central lines (aOR, 0.44 [95% CI, .27-.74]), and associated with USA300 in people who inject drugs (aOR, 4.58 [95% CI, 1.16-17.95]).ConclusionsMost of the decline in MRSA BSIs was from decreases in USA100 BSI incidence. Prevention of USA300 MRSA BSIs in the community will be needed to further reduce burden from MRSA BSIs.
| S-EPMC6708714 | biostudies-literature
Project description:OBJECTIVES:To evaluate the association of USA300 genotype with outcomes in persons with MRSA bacteremia and examine the epidemiology of MRSA bacteremia over time. METHODS:Population-based surveillance for MRSA bacteremia was performed in 8-county Atlanta from 2005 to 2008. Cases of MRSA bacteremia were classified as healthcare-associated hospital-onset (HAHO), healthcare-associated community-onset (HACO), or community-associated (CA) disease. A survival analysis was performed on a nested cohort of cases with isolates characterized by pulse field gel electrophoresis (PFGE). RESULTS:4344 MRSA bacteremia cases were identified; 2579 (59.4%) HACO, 1144 (26.3%) HAHO; and 601 (13.8%) CA. Overall incidence rates of MRSA bacteremia declined from 33.9/100,000 in 2005-24.8/100,000 in 2008. Rates were highest in persons ? 65 years, blacks, males, and persons with AIDS. In multivariate analysis of 1104 cases, USA300 genotype was associated with increased in-hospital mortality (HR 1.63, 95% CI 1.19-2.23). USA300 strains were also associated with increased mortality when compared to USA100 strains (HR 1.79, 95% CI 1.24-2.58). CONCLUSIONS:MRSA bacteremia incidence declined over 4 years but CA disease rates remained stable. Persons with HIV, the elderly, and blacks were disproportionately affected. Bacteremia due to USA300 MRSA strains was associated with increased mortality, suggesting that USA300 strains may be more virulent.
| S-EPMC2975870 | biostudies-literature
Project description:The USA300 North American epidemic (USA300-NAE) clone of methicillin-resistant Staphylococcus aureus has caused a wave of severe skin and soft tissue infections in the United States since it emerged in the early 2000s, but its geographic origin is obscure. Here we use the population genomic signatures expected from the serial founder effects of a geographic range expansion to infer the origin of USA300-NAE and identify polymorphisms associated with its spread. Genome sequences from 357 isolates from 22 U.S. states and territories and seven other countries are compared. We observe two significant signatures of range expansion, including decreases in genetic diversity and increases in derived allele frequency with geographic distance from the Pennsylvania region. These signatures account for approximately half of the core nucleotide variation of this clone, occur genome wide, and are robust to heterogeneity in temporal sampling of isolates, human population density, and recombination detection methods. The potential for positive selection of a gyrA fluoroquinolone resistance allele and several intergenic regions, along with a 2.4 times higher recombination rate in a resistant subclade, is noted. These results are the first to show a pattern of genetic variation that is consistent with a range expansion of an epidemic bacterial clone, and they highlight a rarely considered but potentially common mechanism by which genetic drift may profoundly influence bacterial genetic variation.IMPORTANCE The process of geographic spread of an origin population by a series of smaller populations can result in distinctive patterns of genetic variation. We detect these patterns for the first time with an epidemic bacterial clone and use them to uncover the clone's geographic origin and variants associated with its spread. We study the USA300 clone of methicillin-resistant Staphylococcus aureus, which was first noticed in the early 2000s and subsequently became the leading cause of skin and soft tissue infections in the United States. The eastern United States is the most likely origin of epidemic USA300. Relatively few variants, which include an antibiotic resistance mutation, have persisted during this clone's spread. Our study suggests that an early chapter in the genetic history of this epidemic bacterial clone was greatly influenced by random subsampling of isolates during the clone's geographic spread.
| S-EPMC5750399 | biostudies-literature
Project description: Not available
| S-EPMC5091374 | biostudies-literature