Continued Emergence of USA300 Methicillin-ResistantStaphylococcus aureusin the United States: Results from a Nationwide Surveillance Study

2014 ◽  
Vol 35 (3) ◽  
pp. 285-292 ◽  
Author(s):  
Daniel J. Diekema ◽  
Sandra S. Richter ◽  
Kristopher P. Heilmann ◽  
Cassie L. Dohrn ◽  
Fathollah Riahi ◽  
...  
Keyword(s):  
Protein A ◽  
Bloodstream Infections ◽  
The United States ◽  
Multidrug Resistant ◽  
Pfge Type ◽  
Staphylococcal Protein A ◽  
Single Strain ◽  
Healthcare Settings ◽  
Nationwide Surveillance ◽  
Strain Type

Background.The epidemiology of methicillin-resistantStaphylococcus aureus(MRSA) is changing, with USA300 emerging first in community and then in healthcare settings. We performed nationwide surveillance to assess recent trends in the molecular epidemiology of MRSA.Methods.One hundred consecutive unique clinically significantS. aureusisolates were recovered from patients at each of 43 US centers between July 1, 2011, and December 31, 2011. Susceptibility testing, pulsed-field gel electrophoresis (PFGE), staphylococcal protein A gene (spa) and staphylococcal cassette chromosome mec typing, and Panton-Valentine leukocidin detection were performed on all MRSA isolates.Results.Of 4,131 isolates collected, 2,093 (51%) were MRSA. Specimen sources of MRSA isolates included wound or abscess (54%), blood (24%), lower respiratory tract (11%), and other sterile site (10%). Thirty percent were isolated more than 48 hours after hospital admission (ie, were associated with nosocomial acquisition of infection). USA300 was the most common PFGE type (1,269 isolates; 61%), overall and in all regions, followed by USA100 (368 isolates; 18%). Among 173spatypes found, the most common were t008 (51%) and t002 (18%); no otherspatype accounted for more than 2% of isolates. One strain type (USA300/t008/IV) constituted almost half of all MRSA isolates (1,005 isolates; 48%) and was the most common at all body sites, causing 37% of MRSA bloodstream infections (BSIs) and 38% of nosocomial MRSA infections. Multidrug-resistant phenotypes were found among 34 USA300 isolates (3%) from 18 states.Conclusions.The USA300 PFGE type continues to advance nationwide. A single strain type (USA300/t008/IV) predominates in all regions and infection sites and is now more common than USA 100 as a cause of MRSA BSI and nosocomial infections. Although most USA300 retain typical susceptibility profiles, multidrug-resistant phenotypes are emerging.

scholarly journals Candida auris and Carbapenemase-Producing Organism Prevalence in an Extended Stay Pediatric Hospital, Chicago, Illinois, 2019

2020 ◽  
Vol 41 (S1) ◽  
pp. s145-s146
Author(s):  
Kelly Walblay ◽  
Tristan McPherson ◽  
Elissa Roop ◽  
David Soglin ◽  
Ann Valley ◽  
...  
Keyword(s):  
The United States ◽  
Multidrug Resistant ◽  
Pediatric Hospital ◽  
Mechanical Ventilators ◽  
Candida Auris ◽  
Term Care ◽  
Healthcare Settings ◽  
High Acuity ◽  
Gastrostomy Tubes

Background:Candida auris and carbapenemase-producing organisms (CPO) are multidrug-resistant organisms that can colonize people for prolonged periods and can cause invasive infections and spread in healthcare settings, particularly in high-acuity long-term care facilities. Point-prevalence surveys (PPSs) conducted in long-term acute-care hospitals in the Chicago region identified median prevalence of colonization to be 31% for C. auris and 24% for CPO. Prevalence of C. auris colonization has not been described in pediatric populations in the United States, and limited data exist on CPO colonization in children outside intensive care units. The Chicago Department of Public Health (CDPH) conducted a PPS to assess C. auris and CPO colonization in a pediatric hospital serving high-acuity patients with extended lengths of stay (LOS). Methods: CDPH conducted a PPS in August 2019 in a pediatric hospital with extended LOS to screen for C. auris and CPO colonization. Medical devices (ie, gastrostomy tubes, tracheostomies, mechanical ventilators, and central venous catheters [CVC]) and LOS were documented. Screening specimens consisted of composite bilateral axillae and groin swabs for C. auris and rectal swabs for CPO testing. The Wisconsin State Laboratory of Hygiene tested all specimens. Real-time polymerase chain reaction (PCR) assays were used to detect C. auris DNA and carbapenemase genes: blaKPC, blaNDM, blaVIM, blaOXA-48, and blaIMP (Xpert Carba-R Assay, Cepheid, Sunnyvale, CA). All axillae and groin swabs were processed by PCR and culture to identify C. auris. For CPO, culture was only performed on PCR-positive specimens. Results: Of the 29 patients hospitalized, 26 (90%) had gastrostomy tubes, 24 (83%) had tracheostomies, 20 (69%) required mechanical ventilation, and 3 (10%) had CVCs. Also, 25 (86%) were screened for C. auris and CPO; 4 (14%) lacked parental consent and were not swabbed. Two rectal specimens were unsatisfactory, producing invalid CPO test results. Median LOS was 35 days (range, 1–300 days). No patients were positive for C. auris. From CPO screening, blaOXA-48 was detected in 1 patient sample, yielding a CPO prevalence of 3.4% (1 of 29). No organism was recovered from the blaOXA-48 positive specimen. Conclusions: This is the first documented screening of C. auris colonization in a pediatric hospital with extended LOS. Despite a high prevalence of C. auris and CPOs in adult healthcare settings of similar acuity in the region, C. auris was not identified and CPOs were rare at this pediatric facility. Additional evaluations in pediatric hospitals should be conducted to further understand C. auris and CPO prevalence in this population.Funding: NoneDisclosures: None

scholarly journals 129. Antimicrobial Activity of Ceftazidime–avibactam and Comparator Agents Tested against Gram-Negative Organisms Isolated from Patients with Bloodstream Infections in United States Medical Centers (2017–2018)

2019 ◽  
Vol 6 (Supplement_2) ◽  
pp. S93-S94
Author(s):  
Cecilia G Carvalhaes ◽  
Mariana Castanheira ◽  
Rodrigo E Mendes ◽  
Helio S Sader
Keyword(s):  
United States ◽  
New York ◽  
Bloodstream Infections ◽  
The United States ◽  
Multidrug Resistant ◽  
Medical Centers ◽  
Carbapenem Resistant ◽  
Gram Negative Organisms ◽  
Esbl Producers

Abstract Background We evaluated the antimicrobial susceptibility of Enterobacterales (ENT) and P. aeruginosa (PSA) causing bloodstream infections (BSIs) in the United States (US) hospitals. Methods A total of 3,317 ENT and 331 PSA isolates were consecutively collected (1/patient) from patients with BSI in 68 US medical centers in 2017–2018 and tested for susceptibility (S) by reference broth microdilution methods in a central laboratory as part of the International Network for Optimal Resistance Monitoring (INFORM) Program. β-Lactamase screening was performed by whole-genome sequencing on ENT with decreased S to broad-spectrum cephalosporins (ESBL phenotype). Results The most common ENT species isolated from BSI were E. coli (EC; 41.9% of ENT), K. pneumoniae (KPN; 24.4%), and E. cloacae (ECL; 8.7%), and the most active agents against ENT were ceftazidime–avibactam (CAZ-AVI; 99.9%S), amikacin (AMK; 99.6%S) and meropenem (MEM; 99.3%S). CAZ-AVI was active against all EC and KPN isolates (100.0%S). Only 2 ENT isolates (0.06%) were CAZ-AVI resistant, 2 NDM-1-producing ECL isolated in the New York City area. Ceftolozane–tazobactam (C-T) and piperacillin–tazobactam (PIP-TAZ) showed good activity against EC and KPN (92.2–98.9%S; Table), with limited activity against ECL (81.9–83.7%S). The most common ESBLs were CTX-M-type, which was observed in 93% of ESBL producers (mainly CTX-M-15 [64% of ESBL producers] and CTX-M-27 [13%]), and OXA-1/OXA-30 (42%); 42% of ESBL producers (n = 333, excluding carbapenemase producers) displayed ≥2 ESBL genes, mainly CTX-M-15 and OXA-1/OXA-30 (40% of ESBL producers). The most active agents against ESBL producers were CAZ-AVI (100.0%S), imipenem (99.4%S), and colistin (COL; 99.1%S). Only CAZ-AVI (99.4%S), AMK (96.2%S) and MEM (92.8%S) were active against >90% of multidrug-resistant (MDR) ENT. Among 19 carbapenem-resistant ENT (CRE; 0.6% of ENT), 9 produced a KPC-like, 2 an NDM-1, and 2 an NMC-A; carbapenemase genes were not found in 6 CRE isolates. COL (100.0%S), CAZ-AVI (98.5%S), AMK (98.5%S), C-T (98.1%S), and tobramycin (97.0%S) were very active against PSA. Conclusion CAZ-AVI exhibited potent in vitro activity and great spectrum against ENT (99.9%S) and PSA (98.5%) isolated from patients with BSI from US hospitals. Disclosures All authors: No reported disclosures.

scholarly journals MRSA contamination in ambulances: a systematic review

2019 ◽  
Vol 29 (Supplement_4) ◽  
Author(s):  
M Fattorini ◽  
C Quercioli ◽  
G Messina ◽  
N Nante
Keyword(s):  
Systematic Review ◽  
Medical Equipment ◽  
Bloodstream Infections ◽  
Multidrug Resistant ◽  
European Countries ◽  
Hospital Environment ◽  
Resistant Organism ◽  
Healthcare Settings ◽  
Search Terms ◽  
Potential Reservoir

Abstract Background Methicillin-resistant Staphylococcus aureus (MRSA) is a multidrug resistant organism (MDRO) frequently involved in skin, soft tissue and bone infections. Moreover, it is one of the most frequently isolated pathogen in bloodstream infections in European countries. Because of its capacity to survive on inanimate surfaces, this microorganism could be detected not only on hospital environment, but also in other healthcare settings such as ambulances. We performed a systematic review in order to study the level of MRSA contamination in ambulances (vehicle surfaces and medical equipment). Methods In March 2019 we searched studies in PubMed using the key search terms “MRSA, ambulance”. We included different designs of studies in English. Results The research yielded 18 publications: after title, abstract and full text’s analysis, 9 manuscripts were included in this review. Studies were conducted from 2007 to 2018 in USA, Egypt, Poland, Germany and South Korea. Overall, the number of ambulances sampled for MRSA was 511 (min. 3-max. 150), and 64 (12.5%) resulted contaminated by MRSA. Sampling points examined for each vehicle varied from 5 to 33, for a total of 5872 (min. 39-max. 2136) samplings performed. The amount of MRSA positive samplings was 145/5872 (2.5%) (min. 1-max. 43). Stretcher resulted the most frequently contaminated fomite (29 of the 145 MRSA positive samplings, 20%). Conclusions Despite MRSA prevalence is decreasing in Europe, recent studies showed how this MDRO could still be responsible of a remarkable burden in terms of attributable deaths and costs. Implementing effective sanitation procedures with a continuative monitoring of the processes is highly recommended in all the healthcare settings, including ambulances. Automated terminal disinfection of these vehicles, adopting technologies such as ultraviolet germicidal irradiation or hydrogen peroxide aerosol, could reduce bacterial contamination hosted on surfaces and medical equipment. Key messages Although the percentage of isolates of MRSA in European countries is decreasing, the burden this multidrug resistant organism in terms of mortality and costs remains remarkable. Ambulances must be considered as a potential reservoir of MRSA because of its ability to survive on inanimate surfaces, and adequate sanitation procedures should be frequently performed.

scholarly journals Comparison of the In Vitro Susceptibility of Ceftolozane-Tazobactam With the Cumulative Susceptibility Rates of Standard Antibiotic Combinations When Tested Against Pseudomonas aeruginosa From ICU Patients With Bloodstream Infections or Pneumonia

2019 ◽  
Vol 6 (6) ◽  
Author(s):  
Dee Shortridge ◽  
Michael A Pfaller ◽  
S J Ryan Arends ◽  
Janet Raddatz ◽  
Daryl D DePestel ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Bloodstream Infections ◽  
The United States ◽  
Multidrug Resistant ◽  
In Vitro Susceptibility ◽  
Patients At Risk ◽  
Seriously Ill Patients ◽  
Tract Infections ◽  
Hospital Acquired

Abstract Background Pseudomonas aeruginosa remains an important cause of hospital-acquired infections in the United States and is frequently multidrug-resistant (MDR). The Infectious Diseases Society of America guidelines recommend empiric combination therapy that includes an antipseudomonal β-lactam with an aminoglycoside or fluoroquinolone likely to cover ≥95% of P. aeruginosa infections in seriously ill patients at risk of having an MDR pathogen. Ceftolozane is an antipseudomonal cephalosporin, combined with the β-lactamase inhibitor tazobactam. Ceftolozane-tazobactam is approved for treatment of complicated urinary tract infections and complicated intra-abdominal infections. A phase 3 clinical trial for the treatment of hospital-acquired pneumonia including ventilator-associated pneumoniae was recently completed. We compared the in vitro susceptibility rate of ceftolozane-tazobactam with the cumulative susceptibility rates of antibiotic combinations commonly used against P. aeruginosa. Methods Isolates were collected from intensive care unit patients hospitalized in 32 US hospitals from 2011 to 2017. The susceptibilities of 1543 P. aeruginosa isolates from bloodstream infections (198 isolates, 12.8%) or pneumonia (1345 isolates, 87.2%) were determined for ceftolozane-tazobactam and comparators. Results The most active antimicrobials were colistin (99.4% susceptible), amikacin (98.1% susceptible), and ceftolozane-tazobactam (96.5% susceptible). The susceptibilities to other antipseudomonal β-lactams and fluoroquinolones were <84%. A cumulative susceptibility of ≥95% was reached for cefepime, ceftazidime, meropenem, and piperacillin-tazobactam only in combination with amikacin due to the lower susceptibilities of gentamicin, ciprofloxacin, and levofloxacin. Monotherapies that exceeded 95% were ceftolozane-tazobactam, amikacin, and colistin. Conclusions Ceftolozane-tazobactam monotherapy is likely to be active against more isolates than a combination of another β-lactam and a fluoroquinolone or gentamicin for serious P. aeruginosa infections.

scholarly journals 1589. Ceftolozane–Tazobactam Activity Against Difficult-to-Treat Resistance in Pseudomonas aeruginosa from Bloodstream Infections in US Hospitals

2019 ◽  
Vol 6 (Supplement_2) ◽  
pp. S580-S580
Author(s):  
Dee Shortridge ◽  
S J Ryan Arends ◽  
Leonard R Duncan ◽  
Jennifer M Streit ◽  
Robert K Flamm
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Bloodstream Infections ◽  
The United States ◽  
Multidrug Resistant ◽  
First Line ◽  
Microdilution Method ◽  
Drug Classes ◽  
Broth Microdilution Method ◽  
Tract Infections ◽  
Abdominal Infections

Abstract Background Infections caused by Pseudomonas aeruginosa (PSA) resistant to first-line agents are difficult to treat and require using more toxic antimicrobials, such as amikacin (AMK) and colistin (COL). Kadri et al. recently described the category of difficult-to-treat resistance (DTR) as intermediate or resistant to all tested first-line agents (fluoroquinolones, carbapenems, and extended-spectrum cephalosporins). Ceftolozane–tazobactam (C-T) is an antibacterial combination of an antipseudomonal cephalosporin and a β-lactamase inhibitor. C-T has been approved in >60 countries to treat complicated urinary tract infections, acute pyelonephritis, and complicated intra-abdominal infections. The filing is in progress for treatment of hospital-acquired pneumonia, including ventilator-associated pneumonia. The Program to Assess Ceftolozane–Tazobactam Susceptibility (PACTS) monitors gram-negative (GN) isolates resistant to C-T worldwide. In this study, the activity of C-T and comparators against PSA bloodstream isolates that are DTR, multidrug-resistant (MDR), or extensively drug-resistant (XDR) were analyzed. Methods A total of 922 PSA isolates from BSI were collected between 2011 and 2018 from 35 PACTS hospitals in the United States. Isolates were tested for C-T susceptibility (S) by the CLSI broth microdilution method. Other antibiotics tested included cefepime (FEP), ceftazidime (CAZ), ciprofloxacin, levofloxacin (LEV), doripenem, imipenem, meropenem (MEM), piperacillin–tazobactam (PIP-TAZ), AMK and COL. Antibiotic-resistant phenotypes analyzed using CLSI (2019) breakpoints included MDR (nonsusceptible to ≥ 1 agent in ≥ 3 drug classes), XDR (susceptible to ≤ 1 agent in ≤ 2 drug classes), or DTR. Results The percent of DTR isolates was 4.8% when compared with 15.2% MDR and 9.3% XDR. The %S for C-T and other first- and second-line agents are shown in the table for each phenotype. Conclusion C-T demonstrated 97.1%S overall for BSI isolates, similar to AMK (97.8%) and COL (99.5%). C-T had better coverage than first-line drugs against MDR (81.4%) and XDR (72.1%), and 50% for the DTR isolates, which represented only 4.8% of isolates. Only AMK and COL had > 75%S for DTR isolates. Disclosures All authors: No reported disclosures.

scholarly journals Genomic Investigation of the Emergence of Invasive Multidrug-Resistant Salmonella enterica Serovar Dublin in Humans and Animals in Canada

2019 ◽  
Vol 63 (6) ◽  
Author(s):  
Chand S. Mangat ◽  
Sadjia Bekal ◽  
Brent P. Avery ◽  
Geneviève Côté ◽  
Danielle Daignault ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Bloodstream Infections ◽  
The United States ◽  
Multidrug Resistant ◽  
Phylogenomic Analysis ◽  
Single Nucleotide Variants ◽  
Single Nucleotide ◽  
Content Type ◽  
Human Infections ◽  
Integrated Program

ABSTRACT Salmonella enterica subsp. enterica serovar Dublin is a zoonotic pathogen that often leads to invasive bloodstream infections in humans that are multidrug resistant. Described here are the results of Canadian national surveillance of S. Dublin from 2003 to 2015 in humans and bovines, principally collected through the Canadian Integrated Program for Antibiotic Resistance Surveillance (CIPARS). An increase in human infections due to multidrug-resistant (MDR) S. Dublin was observed in 2010, many of which were bloodstream infections. Phylogenomic analysis of human and bovine isolates revealed a closely related network that differed by only 0 to 17 single nucleotide variants (SNVs), suggesting some potential transmission between humans and bovines. Phylogenomic comparison of global publicly available sequences of S. Dublin showed that Canadian isolates clustered closely with those from the United States. A high correlation between phenotypic and genotypic antimicrobial susceptibility was observed in Canadian isolates. IS26 replication was widespread among U.S. and Canadian isolates and caused the truncation and inactivation of the resistance genes strA and blaTEM-1B. A hybrid virulence and MDR plasmid (pN13-01125) isolated from a Canadian S. Dublin isolate was searched against NCBI SRA data of bacteria. The pN13-01125 coding sequences were found in 13 Salmonella serovars, but S. Dublin appears to be a specific reservoir. In summary, we have observed the rise of invasive MDR S. Dublin in humans in Canada and found that they are closely related to bovine isolates and to American isolates in their mobile and chromosomal contents.

scholarly journals Molecular Typing and Antimicrobial Susceptibility Profile of Staphylococcus aureus Isolates Recovered from Bovine Mastitis and Nasal Samples

2020 ◽  
Author(s):  
Renata P. Santos ◽  
Fernando N. Souza ◽  
Ana Claudia C. Oliveira ◽  
Antônio F. de Souza Filho ◽  
Juliana Aizawa ◽  
...  
Keyword(s):  
Antimicrobial Resistance ◽  
Antimicrobial Susceptibility ◽  
Protein A ◽  
Bovine Mastitis ◽  
Multidrug Resistant ◽  
Aureus Strain ◽  
Staphylococcal Protein A ◽  
Spa Typing ◽  
Antimicrobial Susceptibility Profile ◽  
High Level

In the present study, we aimed to determine the antimicrobial resistance and genetic structure of a population of S. aureus recovered from transient and persistent intramammary infections and nares/muzzles. We investigated the antimicrobial resistance of 189 S. aureus strains using a broad antimicrobial susceptibility profile. Furthermore, 107 S. aureus isolates were strain-typed using staphylococcal protein-A (spa) typing. Here, a great proportion of strains exhibited multidrug resistance to antimicrobials, including resistance to critically important antimicrobials, although no methicillin-resistant S. aureus strains were found. Our study did not strengthen the idea that extramammary niches (i.e., nares/muzzles) are an important source for S. aureus. A discrepancy in the antimicrobial resistance between S. aureus strains isolated from nasal/muzzles and milk samples was observed. Furthermore, S. aureus isolates from transient and persistent IMIs did not differ by spa typing, suggesting that the persistence of bovine IMIs was determined by cow factors. Thus, the high level of multidrug-resistant S. aureus found in the two herds studied together with the predominance of a well udder-adapted S. aureus strain may contribute to the history of the high prevalence of mastitis caused by S. aureus, leading to great animal and public health concerns.

scholarly journals Genotypic Survey of Recent β-Lactam-Resistant Pneumococcal Nasopharyngeal Isolates from Asymptomatic Children in Chile

1999 ◽  
Vol 37 (11) ◽  
pp. 3725-3730 ◽  
Author(s):  
Giovanni Gherardi ◽  
Jaime S. Inostrozo ◽  
Miguel O'ryan ◽  
Valeria Prado ◽  
Susana Prieto ◽  
...  
Keyword(s):  
The United States ◽  
Multidrug Resistant ◽  
Single Type ◽  
Pfge Type ◽  
Penicillin Binding Protein ◽  
Genetic Lineages ◽  
Asymptomatic Children ◽  
Pneumococcal Strain ◽  
Genotypic Analysis ◽  
Sterile Site

To assess pneumococcal strain variability among young asymptomatic carriers in Chile, we used serotyping, antibiotic susceptibility testing, and genotyping to analyze 68 multidrug-resistant pneumococcal isolates recovered from 54 asymptomatic children 6 to 48 months of age. The isolates represented capsular serotypes 19F (43 isolates), 14 (14 isolates), 23F (7 isolates), 6B (3 isolates), and 6A (1 isolate). Genotypic analysis, which included pulsed-field gel electrophoresis (PFGE) of chromosomal digests, penicillin binding protein (PBP) gene fingerprinting, and dhf gene fingerprinting, revealed that the isolates represented six different genetic lineages. Clear circumstantial evidence of capsular switching was seen within each of four of the genetically related sets. The majority of the isolates, consisting of the 43 19F isolates and 2 type 6B isolates, appeared to represent a genetically highly related set distinct from previously characterized pneumococcal strains. Each of three other genetically defined lineages was closely related to one of the previously characterized clones Spain6B-2, France9V-3, or Spain23F-1. A fifth lineage was comprised of four type 23F isolates that, by the techniques used for this study, were genetically indistinguishable from three recent type 19F sterile-site isolates from the United States. Finally, a sixth lineage was represented by a single type 23F isolate which had a unique PFGE type and unique PBP anddhf gene fingerprints.

Emergence of Community-Associated Methicillin-ResistantStaphylococcus aureusStrains as a Cause of Healthcare-Associated Bloodstream Infections in Korea

2009 ◽  
Vol 30 (2) ◽  
pp. 146-155 ◽  
Author(s):  
Sun Hee Park ◽  
Chulmin Park ◽  
Jin-Hong Yoo ◽  
Su-Mi Choi ◽  
Jung-Hyun Choi ◽  
...  
Keyword(s):  
Clinical Characteristics ◽  
Protein A ◽  
Bloodstream Infections ◽  
Venous Catheter ◽  
Pfge Type ◽  
Type D ◽  
Epidemiological Changes ◽  
Mrsa Strains ◽  
Associated Risk Factors ◽  
Healthcare Associated

Background.The prevalence of community-associated methicillin-resistantStaphylococcus aureus(CA-MRSA) strains causing bloodstream infection (BSI) has not been studied in Korea.Objective.We sought to determine the prevalence of CA-MRSA strains among isolates recovered from patients with MRSA BSIs and to explore epidemiological changes in Korea. We also sought to evaluate clinical characteristics relevant to the development of healthcare-associated BSIs.Methods.We prospectively collected consecutive MRSA isolates from patients with BSI at 4 hospitals from July 1 through November 30, 2007, and we also included MRSA isolates recovered from culture of blood samples collected during a previous year (October 1, 2004 through September 30, 2005) at a different hospital. Molecular typing studies were performed, including pulsed-field gel electrophoresis (PFGE), multilocus sequence typing,Staphylococcusprotein A (spa) typing, and staphylococcal cassette chromosomemec(SCCmec) typing. We compared the clinical characteristics and outcomes of patients with healthcare-associated BSI due to CA-MRSA strains with those of patients with healthcare-associated BSI due to healthcare-associated MRSA (HA-MRSA) strains.Results.There were 76 cases of MRSA BSI, of which 4 (5.3%) were community-associated and 72 (94.7%) were healthcare-associated. Among the 72 HA-MRSA BSIs, 18 (25%) were community onset, and 54 (75%) were hospital onset. PFGE type D-ST72–spaB-SCCmectype IVA MRSA, the predominant genotype of CA-MRSA in Korea, accounted for 19 (25%) of all 76 MRSA BSIs, including 17 (23.6%) of 72 HA-MRSA BSIs and 11 (20.8%) of 53 hospital-onset HA-MRSA BSIs. Patients with healthcare-associated BSIs due to CA-MRSA strains carrying SCCmectype IVA tended to have fewer healthcare-associated risk factors, compared with patients with healthcare-associated BSIs due to HA-MRSA strains carrying other SCCmectypes. The presence of a central venous catheter or other invasive device was the only independent factor differentiating patients infected with hospital-associated genotype strains from patients infected with other strains. Clinical outcomes were similar between both groups.Conclusions.CA-MRSA strains are emerging as a major cause of BSI in healthcare settings in Korea. This changing epidemiology of MRSA poses a challenge to public health and infection control in hospital settings.

scholarly journals Staphylococcal Protein A (spa) Locus Is a Hot Spot for Recombination and Horizontal Gene Transfer in Staphylococcus pseudintermedius

mSphere ◽  
2020 ◽  
Vol 5 (5) ◽  
Author(s):  
Alem Zukancic ◽  
Mubin A. Khan ◽  
Sumayya J. Gurmen ◽  
Quinn M. Gliniecki ◽  
Dayna L. Moritz-Kinkade ◽  
...  
Keyword(s):  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Genetic Factors ◽  
Hot Spot ◽  
Protein A ◽  
Multidrug Resistant ◽  
Staphylococcal Protein A ◽  
Staphylococcus Pseudintermedius ◽  
Content Type ◽  
Staphylococcal Protein

ABSTRACT Staphylococcus pseudintermedius is a major canine pathogen but also occasionally colonizes and infects humans. Multidrug-resistant methicillin-resistant S. pseudintermedius (MDR MRSP) strains have emerged globally, making treatment and control of this pathogen challenging. Sequence type 71 (ST71), ST68, and ST45 are the most widespread and successful MDR MRSP clones. The potential genetic factors underlying the clonal success of these and other predominant clones remain unknown. Characterization of the pangenome, lineage-associated accessory genes, and genes acquired through horizontal gene transfer from other bacteria is important for identifying such factors. Here, we analyzed genome sequence data from 622 S. pseudintermedius isolates to investigate the evolution of pathogenicity across lineages. We show that the predominant clones carry one or more lineage-associated virulence genes. The gene encoding staphylococcal protein A (SpA), a key virulence factor involved in immune evasion and a potential vaccine antigen, is deleted in 62% of isolates. Most importantly, we have discovered that the spa locus is a hot spot for recombination and horizontal gene transfer in S. pseudintermedius, where genes related to restriction modification, prophage immunity, mercury resistance, and nucleotide and carbohydrate metabolism have been acquired in different lineages. Our study also establishes that ST45 is composed of two distinct sublineages that differ in their accessory gene content and virulence potential. Collectively, this study reports several previously undetected lineage-associated genetic factors that may have a role in the clonal success of the major MDR MRSP clones. These data provide a framework for future experimental studies on S. pseudintermedius pathogenesis and for developing novel therapeutics against this pathogen. IMPORTANCE Staphylococcus pseudintermedius is a major canine pathogen but can also occasionally infect humans. Identification of genetic factors contributing to the virulence and clonal success of multidrug-resistant S. pseudintermedius clones is critical for the development of therapeutics against this pathogen. Here, we characterized the genome sequences of a global collection of 622 S. pseudintermedius isolates. We show that all major clones, besides carrying core virulence genes, which are present in all strains, carry one or more lineage-specific genes. Many of these genes have been acquired from other bacterial species through a horizontal gene transfer mechanism. Importantly, we have discovered that the staphylococcal protein A gene (spa), a widely used marker for molecular typing of S. pseudintermedius strains and a potential vaccine candidate antigen, is deleted in 62% of strains. Furthermore, the spa locus in S. pseudintermedius acts as a reservoir to accumulate lineage-associated genes with adaptive functions.

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