Mobile genetic element-driven genomic changes in a community-associated methicillin-resistant Staphylococcus aureus clone during its transmission in a regional community outbreak in Japan.

Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) infections are now a public health concern in both community and healthcare settings worldwide. We previously identified a suspected case of a maternity clinic-centred outbreak of CA-MRSA skin infection in a regional community in Japan by PFGE-based analysis. In this study, we performed genome sequence-based analyses of 151 CA-MRSA isolates, which included not only outbreak-related isolates that we previously defined based on identical or similar PFGE patterns but also other isolates obtained during the same period in the same region. Our analysis accurately defined 133 isolates as outbreak-related isolates, collectively called the TDC clone. They belonged to a CA-MRSA lineage in clonal complex (CC) 30, known as the South West Pacific (SWP) clone. A high-resolution phylogenetic analysis of these isolates combined with their epidemiological data revealed that the TDC clone was already present and circulating in the region before the outbreak was recognized, and only the isolates belonging to two sublineages (named SL4 and SL5) were directly involved in the outbreak. Long persistence in patients/carriers and frequent intrahousehold transmission of the TDC clone were also revealed by this analysis. Moreover, by systematic analyses of the genome changes that occurred in this CA-MRSA clone during transmission in the community, we revealed that most variations were associated with mobile genetic elements (MGEs). Variant PFGE types were generated by alterations of prophages and genomic islands or insertion sequence (IS)-mediated insertion of a plasmid or a sequence of unknown origin. Dynamic changes in plasmid content, which were linked to changes in antimicrobial resistance profiles in specific isolates, were generated by frequent gain and loss of plasmids, most of which were self-transmissible or mobilizable. The introduction of IS256 by a plasmid (named pTDC02) into sublineage SL5 led to SL5-specific amplification of IS256, and amplified IS256 copies were involved in some of the structural changes of chromosomes and plasmids and generated variations in the repertoire of virulence-related genes in limited isolates. These data revealed how CA-MRSA genomes change during transmission in the community and how MGEs are involved in this process.

Prevalence and characterization of community-associated Staphylococcus aureus isolates from human mastitis in Beijing, China.

OBJECTIVES: Staphylococcus aureus (S. aureus) spreads worldwide and occurrence of mastitis caused by it holds significant implications for public health. We aim to reveal the molecular typing, antibiotic resistance and virulence gene profile of S. aureus causing mastitis through investigation. METHODS: A total of 200 isolates of S. aureus were collected from outpatients infected with mastitis in a hospital in Beijing from 2020.7 to 2021.7. The molecular characteristics were analyzed by MLST and spa typing, virulence genes were screened by PCR, antibiotic susceptible test was performed by VITEK® 2 Compact system and phylogenetic analysis was performed by MEGA11 and iTOL. RESULTS: Nineteen sequence types (STs) belonging to 9 clone complexes (CCs) were identified. ST22 was the most dominant clone (77.0%, 154/200). MRSA accounted for 19.0% (38/200) and 89.5% (34/38) of MRSA isolates belonged to CC22 and CC59. The isolates had relatively low levels of antibiotic resistance, with the exception of ß-lactams and macrolides with resistance rates above 50.0%. The carrying rate of pvl in the ST22-MRSA strains were 84.2% and the detection rates of seb and pvl in the MRSA isolates were significantly higher than those in the MSSA isolates, while the hlg, fnbA and sdrD showed opposite results. Whole genome sequenced specimens of MRSA strains X4 and B5 show the same evolutionary origin as ST22 EMRSA-15 (HE681097), which is popular in Europe. CONCLUSIONS: The method based on molecular epidemiology is an important tool for tracking the spread of S. aureus infections. We need to be alert to the major MRSA clones CC22 and CC59 in the region and be vigilant to the possible pandemic and spread of ST22 EMRSA-15.

Relapsing bronchopneumonia due to community-associated methicillin-resistant Staphylococcus aureus: a case report.

BACKGROUND: The emergence of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) has increased the incidence of community-onset MRSA infection. Respiratory tract infections caused by MRSA has been noted for their severity; however, repeated relapses that require extended antibiotic therapy are rare. CASE PRESENTATION: We report a case of relapsing bronchopneumonia caused by CA-MRSA in a 56-year-old man. The patient responded to antibiotics, but repeatedly relapsed after stopping treatment. MRSA was consistently isolated from airway specimens during each relapse. Extended oral antibiotic treatment with trimethoprim/sulfamethoxazole (TMP/SMX) for 6 months achieved infection control. Whole-genome sequencing of the isolated strain revealed that the causative agent was sequence type (ST)1/staphylococcal cassette chromosome mec (SCCmec) type IVa, a clone that is rapidly increasing in Japan. DISCUSSION AND CONCLUSIONS: This patient had an unusual course of MRSA bronchopneumonia with repeated relapses. Although the choice of antibiotics for long-term use in MRSA respiratory tract infections has not been well established, TMP/SMX was effective and well tolerated for long-term therapy in this case. The clinical course of infections related to the rapid emerging clone, ST1/SCCmec type IVa warrants further attention.

Assessing the discriminability of PCR-based open reading frame typing versus single-nucleotide polymorphism analysis via draft whole-genome sequencing of methicillin-resistant Staphylococcus aureus in nosocomial transmission analysis.

Phylogenetic analysis based on single-nucleotide polymorphism (SNP)-based through whole-genome sequencing is recognized as the standard method for probing nosocomial transmission. However, the application of WGS is constrained by the high cost of equipment and the need for diverse analysis tools, which limits its widespread use in clinical laboratory settings. In Japan, the prevalent use of PCR-based open reading frame typing (POT) for tracing methicillin-resistant Staphylococcus aureus (MRSA) transmission routes is attributed to its simplicity and ease of use. Although POT's discriminatory power is considered insufficient for nosocomial transmission analysis, conclusive data supporting this notion is lacking. This study assessed the discriminatory capabilities of SNP analysis and POT across 64 clinical MRSA strains. All 21 MRSA strains of ST5/SCCmec IIa, having more than 16 SNPs, demonstrated distinct clones. Conversely, two strains shared the same POT number and were identified as group A. Among the 12 MRSA strains of ST8/SCCmec IVl with over nine SNPs, five fell into POT group B, and five into POT group C. All four MRSA strains of ST8/SCCmec IVa were classified into POT group D, although they included strains with more than 30 SNPs. Among the 27 MRSA strains of ST1/SCCmec IVa, 14 were classified into POT group E. However, except for two clusters (each comprising two or three strains), all had SNP counts >10 (Fig. 1-D). SNP analysis of MRSA in CC1/SCCmec IV showed that several strains had the same number of SNPs in POT number (106-183-37), even among bacteria with >100 SNPs, indicating POT's limited use in detailed nosocomial transmission analysis.

High Incidence of Metastatic Infections in Panton-Valentine Leucocidin-Negative, Community-Acquired Methicillin-Resistant Staphylococcus aureus Bacteremia: An 11-Year Retrospective Study in Japan.

Panton-Valentine leucocidin (PVL)-negative community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) was originally disseminated in Japan and has since replaced healthcare-associated MRSA (HA-MRSA). However, the clinical characteristics of CA-MRSA bacteremia (CA-MRSAB) compared with those of HA-MRSA bacteremia (HA-MRSAB) are unknown. We aim to clarify differences and investigate associations between the clinical manifestations and virulence genes associated with plasma-biofilm formation in PVL-negative CA-MRSA. From 2011 to 2021, when CA-MRSA dramatically replaced HA-MRSA, 79 MRSA strains were collected from blood cultures and analyzed via SCCmec typing and targeted virulence gene (lukSF-PV, cna, and fnbB) detection. The incidence of metastatic infection was significantly higher in CA-MRSAB than in HA-MRSAB. PVL genes were all negative, although cna and fnbB were positive in 55.6% (20/36) and 50% (18/36) of CA-MRSA strains and 3.7% (1/27) and 7.4% (2/27) of HA-MRSA strains, respectively. cna and fnbB carriage were not associated with the development of metastatic infections in MRSAB; however, the bacteremia duration was significantly longer in CA-MRSAB harboring cna. CA-MRSAB may be more likely to cause metastatic infections than HA-MRSAB. Since CA-MRSA is dominant in Japan, suspected metastatic infection foci should be identified by computed tomography, magnetic resonance imaging, and echocardiography when treating MRSAB.

Community-associated methicillin-resistant Staphylococcus aureus infection of diabetic foot ulcers in an eastern diabetic foot center in a tertiary hospital in China: a retrospective study.

BACKGROUND: Diabetic foot concerns are a major public health problem. Methicillin-resistant Staphylococcus aureus (MRSA) plays a significant role in diabetic foot ulcers. Community-associated MRSA has become notorious for skin and skin soft tissue infections over the last two decades. This study investigated MRSA infection in diabetic foot patients at a tertiary hospital, focusing on the epidemiology and characteristics of community-associated MRSA. METHODS: A total of 149 patients with diabetic foot infection whose culture results indicated Staphylococcus aureus as the source were selected. Epidemiological investigations, clinical characteristics, laboratory index records, antibiotic susceptibility analysis, and clinical outcome tracking were performed in all cases. Based on oxacillin resistance using the Vitek Compact 2 system, cases were divided into methicillin-sensitive Staphylococcus aureus and MRSA groups. Subgroup analysis of the MRSA group was performed in accordance with the Centers for Disease Control definition: community-associated MRSA and hospital-associated MRSA. RESULTS: The MRSA group (n = 41, 27.5%) had a longer duration of ulcers and hospital stay and higher hospitalization costs than the methicillin-sensitive Staphylococcus aureus group (n = 108, 72.5%). According to the classification criteria of Infectious Diseases Society of America, the severity of infection in the community-associated MRSA group was higher than that in the hospital-associated MRSA group. The analysis of antimicrobial susceptibility of 41 MRSA isolates showed that the resistance rates to erythromycin, clindamycin, quinolone, gentamicin, tetracycline, and rifampicin were 78.0%, 68.3%, 31.7%, 17.1%, 9.8%, and 2.4%, respectively. All the MRSA strains were sensitive to linezolid, tigecycline, and vancomycin. The resistance rates to quinolones and gentamycin in the community-associated MRSA group (both 0%) were lower than those in the hospital-associated MRSA group. CONCLUSION: Emergence of MRSA in diabetic foot ulcer was associated with a prolonged wound duration and increased consumption of medical resources. Community-associated MRSA strains predominated among MRSA isolates from diabetic foot wounds and caused more severe infections.

Comparative analysis of genomic characteristics, virulence and fitness of community-associated Staphylococcus aureus ST121 clone causing fatal diseases in China and other CA-MRSA clones.

The increasing rate of community-associated Staphylococcus aureus (CA-SA) worldwide has aroused global public concern for decades. Although ST121 clone is one of the prevalent CA-SA in China, there is still limited knowledge about it. In this study, we conducted a genomic analysis of 28 CA-SA ST121 isolates from severe bloodstream infection cases and 175 ST121 isolates from the public database. Phylogenetic analysis revealed the consistency and the complexity of global ST121 lineages, and suggested potential cross-country even cross-continental transmission of ST121 isolates. By investigating the virulence and fitness between ST121-CA-methicillin-resistant SA (CA-MRSA) and other CA-MRSA clones, we found that ST121-MRSA exhibits virulence comparable to the highly virulent USA300 clone, exceeding that of the predominant CA-MRSA lineage ST59 in China and the other American CA-MRSA clone MW2. Notably, based on analyses of virulence genes, eta, etb, edin-C and egc were only found in ST121, suggesting that the high virulence of ST121 may be attributed to the combination of these virulence factors encoded by mobile genetic elements. However, results of experiments in mice nasal and human alveolar epithelial cells showed that the colonization capacity of ST121 is much lower than that of other clones. Moreover, ST121-MRSA displayed much lower acid tolerance, suggesting that ST121-MRSA may not have such capacity to achieve the epidemiological success of other CA-MRSA clones and become the dominant lineage. Our findings expand current understanding of the epidemiology and pathogenicity of the hypervirulent ST121 clone, and highlight the importance of colonization capacity and environmental adaption in MRSA epidemiological success.

Evaluation of Potential Factors Influencing the Dissemination of Multidrug-Resistant Klebsiella pneumoniae and Alternative Treatment Strategies.

The increasing reports of multidrug-resistant Klebsiella pneumoniae have emerged as a public health concern, raising questions about the potential routes for the evolution and dissemination of the pathogenic K. pneumoniae into environmental reservoirs. Potential drivers of the increased incidence of antimicrobial-resistant environmental K. pneumoniae include the eminent global climatic variations as a direct or indirect effect of human activities. The ability of microorganisms to adapt and grow at an exponential rate facilitates the distribution of environmental strains with acquired resistant mutations into water systems, vegetation, and soil which are major intersection points with animals and humans. The bacterial pathogen, K. pneumoniae, is one of the critical-priority pathogens listed by the World Health Organization, mostly associated with hospital-acquired infections. However, the increasing prevalence of pathogenic environmental strains with similar characteristics to clinical-antibiotic-resistant K. pneumoniae isolates is concerning. Considering the eminent impact of global climatic variations in the spread and dissemination of multidrug-resistant bacteria, in this review, we closely assess factors influencing the dissemination of this pathogen resulting in increased interaction with the environment, human beings, and animals. We also look at the recent developments in rapid detection techniques as part of the response measures to improve surveillance and preparedness for potential outbreaks. Furthermore, we discuss alternative treatment strategies that include secondary metabolites such as biosurfactants and plant extracts with high antimicrobial properties.

Increasing of New CA-MRSA Infections Detected in people living with HIV Who Engage in Chemsex in Barcelona: An Ambispective Study.

INTRODUCTION: There are no data on community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) infections in the context of the chemsex phenomenon. This study aimed to characterize CA-MRSA-related infections in a cohort of people living with HIV (PLWH) who engage in chemsex. METHODS: At the Hospital Clinic of Barcelona, from February 2018 to January 2022, we analyzed CA-MRSA infections diagnosed in a cohort of PLWH who engage in chemsex. Epidemiological, behavioral and clinical variables were assessed. Mass spectrometry identification and antimicrobial susceptibility testing were performed on MRSA isolates. Pulse field electrophoresis was used to assess the clonality of the MRSA strains. The presence of Panton-Valentine leukocidin was also investigated. RESULTS: Among the cohort of 299 participants who engage in chemsex, 25 (8%) with CA-MRSA infections were identified, 9 at baseline and 16 with incident cases; the cumulative incidence was 5.5% (95% CI: 3.2%, 8.8%). The most common drugs were methamphetamine (96%) and GHB/GBL (92%). Poly-consumption and slamming were reported by 32% and 46%, respectively. CA-MRSA was isolated from the infection sites of 20 participants, and CA-MRSA colonization was confirmed in the remaining 5 persons. Seventy-one percent had used antibiotics in the previous year. All participants presented with skin and soft tissue infections, 28% required hospitalization, and 48% had recurrence. Of the 23 MRSA isolates further studied, 19 (82,6%) belonged to the same clone. Panton-Valentine leukocidin was detected in all isolates. CONCLUSION: PLWH who engage in chemsex may present with CA-MRSA infections. Clinical suspicion and microbiological diagnosis are required to provide adequate therapy, and CA-MRSA prevention interventions should be designed.

Community-associated Clostridioides difficile infection in a general hospital from Argentina.

Toxin-producing Clostridioides difficile infection (CDI) is the leading cause of hospital-acquired diarrhea. However, it is now recognized as a cause of diarrhea in the community. This single-center study aimed to determine the epidemiological origin of CDI cases between January 2014 and December 2019 and to compare demographic characteristics, comorbidities, risk factors, severity, and mortality of community CDI with healthcare facility-associated CDI. There were 52 CDI cases from the community (34.4%). Community patients were significantly younger (53 yo vs. 65 yo), less comorbid (Charlson Index 1.65 vs. 3.98), and less severe (only one case). The main risk factor was the use of antibiotics in the previous 90 days (65%). However, we did not find any known risk factor in 7 patients.

A Fatal Case of Disseminated Infection Caused by Community-Associated Methicillin-Resistant Staphylococcus aureus USA300 Clone.

Methicillin-resistant Staphylococcus aureus (MRSA) USA300 is a representative community-associated MRSA (CA-MRSA) clone worldwide. Herein, we report the case of a patient with USA300 clone infection who could not be salvaged. A 25-year-old man who had sex with men presented with symptoms including fever persisting for one week and skin lesions located on the buttocks. Computed tomography imaging showed multiple nodules and consolidations, especially in the peripheral lung fields, right iliac vein thrombosis, and pyogenic myositis of medial thighs bilaterally. Blood cultures revealed MRSA bacteremia. The patient's condition deteriorated rapidly, complicated by acute respiratory distress syndrome and infective endocarditis. Despite the intubation on the 6th hospital day, he died on the 9th day. Multilocus sequence typing of this patient's MRSA strain revealed sequence type 8 with a staphylococcal cassette chromosome of mec type IVa, Panton-Valentine leukocidin gene, and the arginine catabolic mobile element, indicating presence of the USA300 clone. Patients with CA-MRSA skin lesions presenting with furuncles or carbuncles on the lower body are at a higher risk of severe disease. The patient's background, appearance, and location of skin lesions are critical for the early diagnosis of severe CA-MRSA infection.

Prevalence and molecular characteristics of community-associated methicillin-resistant Staphylococcus aureus in the respiratory tracts of Chinese adults with community-acquired pneumonia.

BACKGROUND: Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) is an important pathogen causing healthcare-associated infections. In recent years, an increasing number of CA-MRSA clones have emerged and rapidly spread in the community and hospital settings in China. OBJECTIVES: To investigate the molecular epidemiology and resistance of CA-MRSA in the respiratory tracts of Chinese adults with community-acquired pneumonia (CAP). METHODS: A total of 243 sputum samples were collected from adult patients with CAP at the Nantong Hospital in China between 2018 and 2021. S. aureus was identified using PCR, and its susceptibility to 14 antimicrobials was tested using the broth dilution method. Genomic characterization of respiratory CA-MRSA and our previously collected intestinal CA-MRSA isolates was performed using whole-genome sequencing, and the evolutionary relationships of these isolates were assessed using phylogenetic analysis. RESULTS: The CA-MRSA colonization rate among adults with CAP in China was 7.8 % (19/243). Antimicrobial resistance analysis revealed that the proportion of multidrug-resistant respiratory CA-MRSA isolates (100 %) was higher than that of intestinal CA-MRSA isolates (6.3 %). Among the 35 CA-MRSA isolates, 10 MLST types were identified and clustered into five clone complexes (CCs). CC5 (48.6 %) and CC88 (20 %) were predominant CA-MRSA clones. Notably, the CC5 clone ST764/ST6292-MRSA-II-t002 was identified as the major lineage causing respiratory tract infections in Chinese adults with CAP. CONCLUSIONS: The prevalence of CA-MRSA among Chinese adults with CAP is high and often involves ST764/ST6292-MRSA-II-t002 as the causal pathogen.

Epidemiology and Risk Factors of Community-Associated Bloodstream Infections in Zhejiang Province, China, 2017-2020.

Purpose: Community-associated bloodstream infection (CA-BSI) is increasing in many community settings. However, the clinical significance and epidemiology of CA-BSI present in hospital admissions in China are not well established. In this work, we identified the risk factors in outpatients presenting with CA-BSI, and investigate the role of procalcitonin (PCT) and hypersensitive C-reactive protein (CRP) in diagnosing different types of the pathogen in patients with acute CA-BSI. Methods: A retrospective study enrolling 219 outpatients with CA-BSI from The Zhejiang People's Hospital from January 2017 to December 2020 was performed. Susceptibility of the isolates obtained from these patients was examined. Subjecting receiver operating characteristic curves (ROC) were constructed to analyze the specificity and sensitivity of PCT, CRP, and WBC in determining infections caused by different bacterial genera. Risk factors for CA-BSI in the emergency setting were analyzed using essential information and simple identification of other pathogenic bacterial species through rapidly tested biomarkers. Results: A total of 219 patients were included in the selection criteria, of which 103 were infected with Gram-positive bacteria (G+) and 116 with Gram-negative bacteria (G-). The PCT was significantly higher in the GN-BSI group than in the GP-BSI group, while no significant difference was observed between the two groups for CRP. Subjecting ROC curves were constructed to analyze WBC, CRP, and PCT, and the area under the curve (AUC) of the PCT in this model was 0.6661, with sensitivity = 0.798 and specificity = 0.489. Conclusion: The PCT between the GP-BSI group and the GN-BSI group was significantly different. By combining the knowledge of clinicians and the clinical signs of patients, PCT should be utilized as a supplementary approach to initially determine pathogens and direct medication in the early stages of clinical practice.

Epidemiology of Primary and Recurrent Healthcare-Associated and Community-Associated Pediatric Clostridioides difficile Infection in Canada, 2015-2020.

Clostridioides difficile infection (CDI) among children remains a concerning cause of morbidity in hospital settings. We present epidemiological and molecular trends in healthcare- and community-associated CDI among children in Canadian inpatient and outpatient settings, including those who experienced recurrent infections.

Risk factors for meticillin-resistant Staphylococcus aureus (MRSA) carriage in MRSA-exposed household pets.

BACKGROUND: Household pets can carry meticillin-resistant Staphylococcus aureus (MRSA) introduced to the home by their human companions. Specific factors promoting pet carriage of this pathogen have not been fully elucidated. OBJECTIVE: This study evaluated MRSA cultured from pets and the home environment in households where a human infected with MRSA had been identified, and aimed to determine potential risk factors for pet MRSA carriage. MATERIALS AND METHODS: Humans diagnosed with community-associated MRSA (CA-MRSA) skin or soft-tissue infection (SSTI) in the mid-Atlantic United States were identified. One hundred forty-two dogs and cats from 57 affected households were identified of which 134 (94.4%) pets and the household environment were sampled for bacterial culture, PCR confirmation and spa-typing for MRSA strain determination. Samples were obtained 3 months later from 86 pets. RESULTS: At baseline, 12 (9.0%) pets carried MRSA. Potential risk factors associated with carriage included pet bed (environmental) MRSA contamination, flea infestation and prior antimicrobial use in the pet. Pets tended to carry human-adapted MRSA strains and spa-types of MRSA isolates cultured from pets were concordant with strains cultured from the home environment in seven of eight homes (87.5%) at baseline. CONCLUSIONS AND CLINICAL RELEVANCE: Results may inform risk-based veterinary clinical recommendations and provide evidence for selective pet testing as a possible alternative to early removal of pets from the homes of humans infected with MRSA. MRSA contamination of the home environment is likely an important risk factor for pet MRSA carriage, and household interventions should be considered to reduce risk of MRSA carriage in exposed pets.

Escalation of antimicrobial resistance among MRSA part 1: focus on global spread.

INTRODUCTION: Staphylococcus aureus produce numerous virulence factors that influence tissue invasion, cytotoxicity, membrane damage, and intracellular persistence allowing them to be very common human pathogens. S. aureus isolates exhibit considerable diversity though specific genotypes have been associated with antimicrobial resistance (AMR) and toxin gene profiles. MRSA is an important pathogen causing both community-acquired (CA) and healthcare-acquired (HCA) infections. Importantly, over the past several decades, both HCA-MRSA and CA-MRSA have spread all over the globe. Even more concerning is that CA-MRSA clones have disseminated into hospitals and HCA-MRSA have entered the community. Factors that enhance spread of MRSA include: poor antimicrobial stewardship and inadequate infection control. The emergence and spread of multidrug resistant (MDR) MRSA has limited therapeutic options. AREAS COVERED: The authors discuss the escalation of MRSA, both HCA-MRSA and CA-MRSA across the globe. A literature search of MRSA was performed via PubMed (up to September 2022), using the key words: antimicrobial resistance; ß-lactams; community-associated MRSA; epidemiology; infection; multidrug resistance; Staphylococcus aureus. EXPERT OPINION: Over the past several decades, MRSA has spread all over the globe. We encourage the judicious use of antimicrobials in accordance with antimicrobial stewardship programs along with infection control measures to minimize the spread of MRSA.

The second nationwide surveillance of antibacterial susceptibility patterns of pathogens isolated from skin and soft-tissue infections in dermatology departments in Japan.

The present study compared trends in antimicrobial resistance patterns in pathogens isolated from skin and soft-tissue infections (SSTIs) in Japan with those of a nationwide survey conducted in 2013. Three organisms that caused most of the SSTIs were collected from 12 dermatology departments in medical centers and 12 dermatology clinics across Japan between April 2019 and August 2020. A total of 390 strains, including 267 Staphylococcus aureus, 109 coagulase-negative staphylococci (CNS), and 14 Streptococcus pyogenes strains were submitted to a central laboratory for antimicrobial susceptibility testing. Patient demographic and clinical information was collated. Methicillin-resistant S. aureus (MRSA) was detected in 25.8% (69/267) of the S. aureus strains. The prevalence of MRSA between the present study and the 2013 survey did not differ significantly. Furthermore, there were no significant differences in MIC values and susceptibility patterns of the MRSA strains to other agents, regardless of a history of hospitalization within 1 year or invasive medical procedures. Methicillin-resistant CNS (MRCNS) was detected in 48.6% (53/109) of CNS isolates, higher than the 35.4% prevalence in the 2013 survey. This difference could be attributed to the heterogeneity in the members of the MRCNS, which comprises multiple staphylococci species, between the 2013 and 2019 surveys. However, it was noted that the susceptibility profiles of the MRCNS to each antibiotic were not significantly different from those identified in the 2013 survey. Most strains of S. pyogenes were susceptible to each antibiotic, similar to the 2013 survey. Continuous monitoring of trends in pathogen and susceptibility profiles is important to advise local public health efforts regarding the appropriate treatment of SSTIs.

Carbapenem-Resistant enterobacterales in individuals with and without health care risk factors -Emerging infections program, United States, 2012-2015.

BACKGROUND: Carbapenem-resistant Enterobacterales (CRE) are usually healthcare-associated but are also emerging in the community. METHODS: Active, population-based surveillance was conducted to identify case-patients with cultures positive for Enterobacterales not susceptible to a carbapenem (excluding ertapenem) and resistant to all third-generation cephalosporins tested at 8 US sites from January 2012 to December 2015. Medical records were used to classify cases as health care-associated, or as community-associated (CA) if a patient had no known health care risk factors and a culture was collected <3 days after hospital admission. Enterobacterales isolates from selected cases were submitted to CDC for whole genome sequencing. RESULTS: We identified 1499 CRE cases in 1194 case-patients; 149 cases (10%) in 139 case-patients were CA. The incidence of CRE cases per 100,000 population was 2.96 (95% CI: 2.81, 3.11) overall and 0.29 (95% CI: 0.25, 0.35) for CA-CRE. Most CA-CRE cases were in White persons (73%), females (84%) and identified from urine cultures (98%). Among the 12 sequenced CA-CRE isolates, 5 (42%) harbored a carbapenemase gene. CONCLUSIONS: Ten percent of CRE cases were CA; some isolates from CA-CRE cases harbored carbapenemase genes. Continued CRE surveillance in the community is critical to monitor emergence outside of traditional health care settings.

Molecular epidemiology and change trend of methicillin-resistant Staphylococcus aureus from invasive infections of a hospital in Hangzhou from 2012 to 2018.

The disease caused by methicillin-resistant Staphylococcus aureus (MRSA) is a global public health challenge that threatens society and patients seriously. Therefore, the molecular epidemiology and change trend of MRSA is essential for the control and treatment of diseases caused by the pathogen in their regions. To explore molecular epidemiology of MRSA in Hangzhou, we collected 162 MRSA isolates from 2012 to 2018, conducted the antimicrobial susceptibility and used polymerase chain reaction(PCR) to test the molecular typing including multilocus sequence typing (MLST), staphylococcal chromosome cassette mec (SCCmec), staphylococcal protein A (spa A) and Panton-Valentine leucocidin (PVL). All the strains was divided into community-associated MRSA (CA-MRSA) or hospital-associated MRSA (HA-MRSA). 162 MRSA isolates were divided into 16 STs and 30 spa types. The major ST type was ST5 (96/162, 59.3%) and the predominant spa type was t311 (83/162, 51.2%). Five SCCmec types were found and the most common SCCmec type was type II (101/162, 61.7%). ST5-II-t311 was the predominant MRSA clone. And the prevalence of ST5 MRSA gradually declined from 2014 to 2018 but the prevalence of ST59 MRSA significantly increased. At the same time, livestock-associated methicillin-resistant Staphylococcus aureus(LA-MRSA) ST398 and ST9 were detected. Twenty-eight isolates were PVL gene positive (28/162, 17.3%). The most prevalent PVL-positive clone was ST59-IVa-t437. Comparing with HA-MRSA, CA-MRSA had a lower probability of ST5 (9.1% vs 67.1%, P=0.000) but a higher probability of ST59 (63.6% vs 11.4%, P=0.000), not only that, it was more likely to carrying PVL-positive gene (36.4% vs 14.3%, P=0.028). In summary, the molecular types of MRSA were getting complex over time. ST5-II-t311 was the predominant clone of MRSA isolate with a downward incidence from 2014 to 2018. ST59 MRSA strains, which is thought community related strain are spreading into hospitals and has an upward incidence from 2014 to 2018.