OBJECTIVES: Bloodstream infections in emergency patients have a high incidence, severe disease progression, and rapid deterioration. Early administration of appropriate antimicrobial agents is crucial for improving patient outcomes. This study aims to investigate the incidence, pathogen distribution, and antimicrobial resistance patterns of bloodstream infections in emergency patients, providing a reference for rational antibiotic use in clinical practice. METHODS: Medical records of patients diagnosed with bloodstream infections in the emergency department of a hospital in Hunan Province between January 2018 and October 2022 were retrospectively collected. Clinical characteristics of bloodstream infection patients were analyzed, and the distribution trends and antimicrobial susceptibility of clinical isolates were examined. RESULTS: During the study period, 2 215 blood culture samples were submitted from the emergency department, with a positivity rate of 13.27%. After excluding eight cases with missing data or suspected contamination, 286 patients with bloodstream infections were included, with community-acquired infections accounting for the majority (85.66%). The most common primary infection site was the urinary tract (24.48%), followed by respiratory tract infections (20.28%) and biliary and intra-abdominal infections (17.13%). The 30-day mortality rate of bloodstream infections was 16.08%. A total of 286 pathogens were isolated, including 181 (63.29%) Gram-negative bacteria, primarily Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa; 101 (35.31%) Gram-positive bacteria, mainly Staphylococcus aureus, Staphylococcus epidermidis, and Streptococcus pneumoniae; and only 4 (1.40%) fungal isolates. Antimicrobial susceptibility testing showed that the key Enterobacteriaceae strains exhibited resistance rates of 2.4% to carbapenems, 16.3% to piperacillin sodium and tazobactam sodium, and 15.3% to ceftazidime, with no detected resistance to tigecycline or polymyxins. The main non-fermentative bacteria showed resistance rates of 29.6% to piperacillin sodium and tazobactam sodium, 13.3% to cefoperazone sodium and sulbactam sodium, and 27.1% to quinolones. Among Gram-negative bacteria, multidrug-resistant strains accounted for 40.9% (74/181), with carbapenem-resistant Escherichia coli and Klebsiella pneumoniae detected in 5.4% (5/92) and 13.6% (6/44) of cases, respectively. No carbapenem-resistant Pseudomonas aeruginosa was identified. Among Gram-positive bacteria, resistance rates to penicillin G, rifampicin, and cefoxitin were 74.7%, 4.2%, and 50%, respectively, with only 3 cases of resistant to glycopeptide antibiotics. CONCLUSIONS Bloodstream infections in emergency patients are predominantly community-acquired, with Gram-negative bacteria being the most common pathogens. The isolated pathogens exhibited relatively low resistance rates to commonly used clinical antibiotics.
Retrospective Studies ; Emergency Service, Hospital/statistics & numerical data* ; Drug Resistance, Bacterial ; Anti-Bacterial Agents/therapeutic use* ; Incidence ; Microbial Sensitivity Tests/statistics & numerical data* ; Bacteremia/microbiology* ; Community-Acquired Infections/microbiology* ; Gram-Negative Bacteria/isolation & purification* ; Blood Culture/statistics & numerical data* ; Humans ; Male ; Female ; Adolescent ; Young Adult ; Adult ; Middle Aged ; Aged ; Aged, 80 and over ; China/epidemiology*

Objective: To describe the clinical characteristics of Mycoplasma pneumoniae infection and analyze the factors associated with co-infections with other pathogens in children, and provide evidence for improvement of community acquired pneumonia (CAP) prevention and control in children. Methods: Based on the surveillance of hospitalized acute respiratory infections cases conducted in Soochow University Affiliated Children's Hospital (SCH), the CAP cases aged <16 years hospitalized in SCH between 2018 and 2021 were screened. The pathogenic test results of the cases were obtained through the laboratory information system, and their basic information, underlying conditions, and clinical characteristics were collected using a standardized questionnaire. The differences in clinical characteristics between M. pneumoniae infection and bacterial or viral infection and the effect of the co-infection of M. pneumoniae with other pathogens on clinical severity in the cases were analyzed; logistic regression was used to analyze the factors associated with the co-infections with other pathogens. Results: A total of 8 274 hospitalized CAP cases met the inclusion criteria. Among them, 2 184 were positive for M. pneumoniae (26.4%). The M. pneumoniae positivity rate increased with age (P<0.001), and it was higher in girls (P<0.001) and in summer and autumn (P<0.001). There were statistically significant differences in the incidence of wheezing, shortness of breath, wheezing sounds and visible lamellar faint shadow on chest radiographs, as well as fever and hospitalization days among M. pneumoniae, bacterial, and viral infection cases (all P<0.05). In the cases aged <60 months years, co-infection cases had higher rates of wheezing, gurgling with sputum and stridor; and in the cases aged ≥60 months, co-infection cases had a higher rate of shortness of breath (all P<0.05). Multifactorial logistic regression analysis showed that being boys (aOR=1.38,95%CI:1.15-1.67), being aged <6 months (aOR=3.30,95%CI:2.25-4.89), 6-23 months (aOR=3.44,95%CI:2.63-4.51), 24-47 months (aOR=2.50,95%CI:1.90-3.30) and 48-71 months (aOR=1.77,95%CI:1.32-2.37), and history of respiratory infection within 3 months (aOR=1.28,95%CI:1.06-1.55) were factors associated with co-infections of M. pneumoniae with other pathogens. Conclusions: M. pneumoniae was the leading pathogen in children hospitalized due to CAP. M. pneumoniae infections could cause fever for longer days compared with bacterial or viral infections; M. pneumoniae was often co-detected with virus or bacteria. Being boys, being aged <72 months and history of respiratory infection within 3 months were associated factors for co-infections.
Bacteria ; Child ; Coinfection/epidemiology* ; Community-Acquired Infections/epidemiology* ; Dyspnea ; Female ; Humans ; Male ; Mycoplasma pneumoniae ; Pneumonia, Mycoplasma/microbiology* ; Respiratory Sounds ; Respiratory Tract Infections/epidemiology* ; Virus Diseases

ObjectiveWorldwide, community-acquired pneumonia (CAP) is a common infection that occurs in older adults, who may have pulmonary comorbidities, including chronic obstructive pulmonary disease (COPD). Although there have been clinical studies on the coexistence of CAP with COPD, there remain some controversial findings. This review presents the current status of COPD in CAP patients, including the disease burden, clinical characteristics, risk factors, microbial etiology, and antibiotic treatment.

Data SourcesA literature review included full peer-reviewed publications up to January 2018 derived from the PubMed database, using the keywords "community-acquired pneumonia" and "chronic obstructive pulmonary disease".

Study SelectionPapers in English were reviewed, with no restriction on study design.

ResultsCOPD patients who are treated with inhaled corticosteroids are at an increased risk of CAP and have a worse prognosis, but data regarding the increased mortality remains unclear. Although Streptococcus pneumoniae is still regarded as the most common bacteria isolated from patients with CAP and COPD, Pseudomonas aeruginosa is also important, and physicians should pay close attention to the occurrence of antimicrobial resistance, particularly in these two organisms.

ConclusionsCOPD is a common and important predisposing comorbidity in patients who develop CAP. COPD often aggravates the clinical symptoms of patients with CAP, complicating treatment, but generally does not appear to affect prognosis.

Community-Acquired Infections ; epidemiology ; microbiology ; mortality ; Humans ; Pneumonia ; epidemiology ; microbiology ; mortality ; Pseudomonas aeruginosa ; pathogenicity ; Pulmonary Disease, Chronic Obstructive ; epidemiology ; microbiology ; mortality ; Risk Factors ; Streptococcus pneumoniae ; pathogenicity

Infective endocarditis (IE) has been increasingly diagnosed in patients without previously detected predisposing heart disease, but its clinical features have yet to be fully determined. A recent single-center study including echocardiographic images and surgical findings investigated the incidence of undiagnosed, clinically silent valvular or congenital heart diseases and healthcare-associated infective endocarditis (HAIE). The study confirmed that a large proportion of patients with IE have no previous history of heart disease. Analysis of underlying disease in these patients showed that undetected mitral valve prolapse was the most common disease, followed by an apparently structurally normal valve. The patients who developed IE of apparently structurally normal valves had different clinical characteristics and worse outcomes. IE involving a structurally normal valve was associated with both nosocomial and non-nosocomial HAIE, whereas community-acquired IE was more frequent than HAIE. The pathophysiologic mechanism involving the development of non-HAIE or community-acquired IE due to predominantly staphylococcal infection in an apparently structurally normal valve is not yet clearly understood. Structurally normal valves are not necessarily free of regurgitation or abnormal turbulence and, given the dynamic nature and fluctuating hemodynamic effects of conditions such as poorly controlled hypertension, end-stage renal disease, and sleep apnea, further investigation is necessary to evaluate the potential role of these diseases in the development of IE. An apparently normal-looking valve is associated with IE development in patients without previously recognized predisposing heart disease, warranting repartition of at-risk groups to achieve better clinical outcomes.
Adult ; Aged ; Community-Acquired Infections/diagnosis/*epidemiology/microbiology/physiopathology/therapy ; Cross Infection/diagnosis/*epidemiology/microbiology/physiopathology/therapy ; Echocardiography, Doppler, Color ; Endocarditis, Bacterial/diagnosis/*epidemiology/microbiology/physiopathology/therapy ; Female ; Heart Valves/*microbiology/physiopathology/ultrasonography ; Humans ; Incidence ; Male ; Middle Aged ; Predictive Value of Tests ; Prognosis ; Risk Factors

PURPOSETo investigate and analyze the clinical and etiological characteristics of community-acquired intraabdominal infections (CIAIs) and hospital-acquired or nosocomial intraabdominal infections (NIAIs) in a comprehensive hospital, to understand the characteristics, pathogen composition, and drug resistance of CIAIs as well as NIAIs, and to provide a reference for clinical treatment.

METHODSWe collected the clinical data of patients with intraabdominal infections admitted to our hospital from June 2013 to June 2014. In vitro drug sensitivity tests were conducted to separate pathogens, and the data were analyzed using the WHONET 5.4 software and SPSS 13.0 software.

RESULTSA total of 221 patients were enrolled in the study, including 144 with CIAIs (55 mild-moderate and 89 severe) and 77 with NIAIs. We isolated 322 pathogenic strains, including 234 strains of gram-negative bacteria, 82 strains of gram-positive bacteria, and 6 strains of fungi. Based on clinical features, NIAIs and severe CIAIs presented significantly higher values in age, length of hospital stay, mortality, and the incidence of severe intra-abdominal infection than mild-moderate CIAIs (p < 0.05). There was no significant difference in the prognosis between NIAIs and severe CIAIs. Primary diseases leading to CIAIs and NIAIs mostly were hepatobiliary diseases and gastrointestinal diseases respectively. Bacteria isolated from various types of IAIs mainly were Enterobacteriaceae; mild-moderate CIAIs mostly were mono-infection of gram-negative bacteria; NIAIs mostly were mixed infections of gram-negative and gram-positive bacteria; and severe CIAIs were from either type of infection. The rate of Extended Spectrum b-Lactamase-producing Escherichia coli and Klebsiella pneumoniae was much higher in NIAIs than in CIAIs (p < 0.05). The antimicrobial drug sensitivity of gram-negative bacteria isolated from NIAIs was significantly lower than that of CIAIs.

CONCLUSIONCIAIs and NIAIs have their own unique clinical features and epidemiological features of pathogens which should be considered during the initial empiric therapy for the rational use of antimicrobial drugs. Regional IAIs pathogenic bacteria have their own features in drug resistance, slightly different from some recommendations of 2010 Infectious Diseases Society of America guidelines.

Adult ; Aged ; Bacterial Infections ; drug therapy ; epidemiology ; Community-Acquired Infections ; drug therapy ; epidemiology ; microbiology ; Cross Infection ; drug therapy ; epidemiology ; microbiology ; Female ; Humans ; Intraabdominal Infections ; drug therapy ; epidemiology ; microbiology ; Male ; Microbial Sensitivity Tests ; Middle Aged ; Prospective Studies

BACKGROUND/AIMS: To enable appropriate antimicrobial treatment for community-onset infections in emergency departments (EDs), data are needed on the resistance profiles of Escherichia coli and Klebsiella pneumoniae, which are the main pathogens of community-onset bacteremia. METHODS: Records were reviewed of 734 patients with E. coli and K. pneumoniae bacteremia who visited the Daegu Fatima Hospital ED, Daegu, Korea between 2003 and 2009. We investigated the demographic data, clinical findings, and antimicrobial susceptibility patterns of the organisms. RESULTS: Of 1,208 cases of community-onset bacteremia, 62.8% were caused by E. coli or K. pneumoniae in an ED of a secondary care hospital. Five hundred and forty-eight cases of E. coli (75%) and 183 cases of K. pneumoniae (25%) were analyzed. Urinary tract infection (43.1%) was most common, followed by intra-abdominal infection (39%) and pneumonia (7.2%). Trimethoprim/sulfamethoxazole, fluoroquinolone, third-generation cephalosporin (3GC) and amikacin resistance rates among E. coli and K. pneumoniae were 22.8%, 19.6%, 6.2%, and 1.3%, respectively. In 2009, the rate of 3GC resistance (10.6%) was significantly higher, compared to the annual averages of 2003 to 2008 (6.1%; p = 0.03). Previous exposure to antibiotics was an independent risk factor for 3GC resistance in multivariate logistic regression analysis. CONCLUSIONS: The rate of 3GC resistance increased in community-onset infections, and previous exposure to antibiotics was an independent risk factor. Despite the increased 3GC resistance in community-onset infections, an amikacin combination therapy could provide an option for treatment of bacteremic patients with previous antibiotic exposure in an ED.
Aged ; Aged, 80 and over ; Bacteremia/epidemiology/*microbiology ; *Cephalosporin Resistance ; Community-Acquired Infections/microbiology ; Emergency Service, Hospital/statistics & numerical data ; Escherichia coli/*physiology ; Female ; Humans ; Klebsiella pneumoniae/*physiology ; Male ; Middle Aged ; Republic of Korea/epidemiology ; Retrospective Studies ; Secondary Care Centers/statistics & numerical data

OBJECTIVEGroup A β-hemolytic streptococcus (GAS) or Streptococcus pyogenes may be encountered in diverse clinical situations in children. A rising incidence of invasive group A streptococcus (IGAS) infections has been noted in children in the past three decades. The aim of this study was to summarize the clinical characteristics and antimicrobial resistance of IGAS in children, and to raise the level of diagnosis and treatment of this infection.

METHODThe clinical data from 19 cases of IGAS younger than 14 years old seen from January 2004 to December 2011 treated in the authors' hospital were analyzed. IGAS infections are defined as the isolation of GAS from a normally sterile site in patients.

RESULTThe 19 cases were identified as IGAS infections, among whom 15 were male and 4 were female, and the ratio of them was 3.75. The age ranged from 1 day to 14 years, with a median age of 4 years. The course of disease was 4 h-10 days. The average length of stay was 12.2 days. In 13 cases the episodes of the infection occurred in winter and spring. In 18 cases the infection was community-acquired. Overall, 10 cases had neck or foot dorsum abscess, four cases had purulent peritonitis, and 3 cases were diagnosed as streptococcal toxic shock syndrome (STSS) complicated with empyema, pyopneumothorax occurred in 1 case and neonatal septicemia in another. Three cases had an underlying disease, including 2 cases wounded in a car accident and 1 case of congenital esophageal atresia and tracheoesophageal fistula. Before the isolation of GAS, 5 cases had stayed in ICUs, the length of ICU stay was 1-32 days, 4 cases had received intubation and mechanical ventilation, the ventilation time was 8 h-24 days, 2 cases had received major surgery; 5 cases had other pathogen coinfection, including 4 cases of abdominal pus at the same time and Escherichia coli was isolated, and 1 case had parainfluenza virus type I coinfection. Peripheral blood leucocyte increased in 18 cases, one case dropped off. The C-reactive protein (CRP) levels increased in all patients, including 16 cases who had 14-160 mg/L, 3 cases had levels higher than 160 mg/L. Twenty strains of GAS were isolated from 19 cases' sterile sites, of them 10 strains were isolated from abscess, 4 strains were isolated from blood and another 4 from ascites. Two strains were from the same patient at different times of pleural effusion. All 20 strains displayed a full susceptibility to cefazolin, levofloxacin and vancomycin, and the rates of resistance to both cefotaxime and penicillin were 10.0%. The rates of resistance to erythromycin and clindamycin were 55.0% and 70.0% respectively. Among the patients 3 cases were cured, 14 cases improved, and 2 cases died, of whom 1 case died of STSS secondary to multiple organ dysfunction, 1 case died of basic disease secondary to multiple organ dysfunction.

CONCLUSIONSkin and soft tissues were the most common IGAS infection sites in children, and IGAS infection also can lead to serious STSS and even can be life threatening. Penicillin and cephalosporin are still sensitive for children IGAS infections.

Abscess ; drug therapy ; epidemiology ; microbiology ; Adolescent ; Anti-Bacterial Agents ; pharmacology ; therapeutic use ; Cephalosporins ; therapeutic use ; Child ; Child, Preschool ; Clindamycin ; therapeutic use ; Community-Acquired Infections ; drug therapy ; epidemiology ; microbiology ; Drug Resistance, Bacterial ; Female ; Humans ; Infant ; Infant, Newborn ; Male ; Microbial Sensitivity Tests ; Retrospective Studies ; Soft Tissue Infections ; drug therapy ; epidemiology ; microbiology ; Streptococcal Infections ; drug therapy ; epidemiology ; microbiology ; Streptococcus pyogenes ; drug effects ; isolation & purification

OBJECTIVETo investigate the epidemic characteristics and pathogenic spectrum of community acquired pneumonia (CAP) in Guangzhou from 2009 to 2012.

METHOD14 major comprehensive hospitals were selected from 11 districts as sentinel hospitals for CAP cases surveillance, including 18 982 223 in total during the 4 years. The characteristics of pathogenic spectrum of CAP were stratified and analyzed by year, age and season.

RESULTS18 982 223 cases were included in the surveillance from year 2009 to 2012, in which 56 618 cases were CAP. The number of CAP cases increased from 8677 in year 2009 to 19 947 in year 2012 in Guangzhou; while the percentage of visits for CAP raised from 0.22% (8677/3 893 800) to 0.41% (19 947/4 839 766). The difference showed statistical significance (χ(2) = 2693.00, P < 0.05). Among the hospitalized CAP cases, 66.05% (10 954/16 585) were aged ≤ 5 years old or > 66 years old. The percentage of cases infected by a single pathogen was 88.11% (14 613/16 585), while co-infected cases accounted for 4.17% (691/16 585). Bacteria accounted for the largest proportion of 65.25% (10 821/16 585) as a single pathogen, followed by mycoplasma 13.54% (2245/16 585), virus 9.01% (1494/16 585) and chlamydia 0.32% (53/16 585). The proportion of virus infection was increasing from 4.74% to 11.64%. The difference showed statistical significance (χ(2) = 135.32, P < 0.05). Bacteria infection was the leading causes for CAP cases in all age groups; however the percentage increased with the increasing of ages. The rate of bacterial infection was increased from 48.35% (2993/6191) among children aged ≤ 5 years old to 81.31% (3873/4763) among adults aged over 65 years (χ(2) = 1632.00, P < 0.05). The rate of atypical pathogens (mycoplasma, chlamydia) for children ( ≤ 15 years old) (25.99%, 1805/6945) was higher than that for adults aged ≥ 16 years old (5.12%, 494/9640) (χ(2) = 2.11, P < 0.05). The effect from season on the pathogenic spectrum was not observed.433 hospitalized CAP cases were dead from 2009 to 2012. Case fatality rate was highest among people aged over 65 years old (4.70%, 224/4763) and lowest among children aged between 6 to 15 years old (0.27%, 2/754).

CONCLUSIONThe incidence of community acquired pneumonia was rising in Guangzhou from 2009 to 2012. Bacteria was the dominant pathogen. Children and old people were the high-risk population of community acquired pneumonia; while co-infection was still at low level.

Adolescent ; Adult ; Aged ; Aged, 80 and over ; Child ; Child, Preschool ; China ; epidemiology ; Community-Acquired Infections ; epidemiology ; microbiology ; Female ; Humans ; Infant ; Male ; Middle Aged ; Pneumonia ; epidemiology ; microbiology ; Sentinel Surveillance ; Young Adult

Although extended-spectrum beta-lactamase-producing Escherichia coli (ESBL-EC) has emerged as a significant community-acquired pathogen, there is little epidemiological information regarding community-onset bacteremia due to ESBL-EC. A retrospective observational study from 2006 through 2011 was performed to evaluate the epidemiology of community-onset bacteremia caused by ESBL-EC. In a six-year period, the proportion of ESBL-EC responsible for causing community-onset bacteremia had increased significantly, from 3.6% in 2006 to 14.3%, in 2011. Of the 97 clinically evaluable cases with ESBL-EC bacteremia, 32 (33.0%) were further classified as healthcare-associated infections. The most common site of infection was urinary tract infection (n=35, 36.1%), followed by biliary tract infections (n=29, 29.9%). Of the 103 ESBL-EC isolates, 43 (41.7%) produced CTX-M-14 and 36 (35.0%) produced CTX-M-15. In the multilocus sequence typing (MLST) analysis of 76 isolates with CTX-M-14 or -15 type ESBLs, the most prevalent sequence type (ST) was ST131 (n=15, 19.7%), followed by ST405 (n=12, 15.8%) and ST648 (n=8, 10.5%). No significant differences in clinical features were found in the ST131 group versus the other group. These findings suggest that epidemic ESBL-EC clones such as CTX-M-14 or -15 type ESBLs and ST131 have disseminated in community-onset infections, even in bloodstream infections, which are the most serious type of infection.
Aging ; Bacteremia/drug therapy/*epidemiology ; Biliary Tract Diseases/epidemiology/microbiology ; Cephalosporin Resistance/genetics ; Cephalosporins/therapeutic use ; Community-Acquired Infections/*epidemiology/microbiology ; Escherichia coli/isolation & purification/metabolism ; Escherichia coli Infections/drug therapy/*epidemiology ; Female ; Humans ; Male ; Microbial Sensitivity Tests ; Molecular Epidemiology ; Multilocus Sequence Typing ; Prevalence ; Retrospective Studies ; Urinary Tract Infections/epidemiology/microbiology ; beta-Lactamases/*metabolism

OBJECTIVETo study the clinical and molecular characteristics of methicillin-resistant Staphylococcus aureus (MRSA) infection in children.

METHODA total of 37 MRSA strains were isolated from hospitalized patients in Children's Hospital of Fudan University from March 2009 to November 2011. The clinical characteristics were investigated by a cohort study. Furthermore, the mecA, Panton-Valentine leucocidin (PVL) genes were detected by polymerase chain reaction (PCR), and the genotypes of SCCmec were determined by multiplex PCR.

RESULT(1) Among the 37 MRSA isolates, infections with 21 were acquired from hospital (HA-MRSA), and 16 isolates were acquired from community (CA-MRSA). (2) In the study, MRSA frequently caused respiratory tract infection, and most of the strains were isolated from intensive care unit (ICU). (3) CA-MRSA was most frequently associated with skin and soft tissue infections (SSTI), suppurative tonsillitis, even pneumonia and septicemia. HA-MRSA infection was more aggressive, most frequently associated with pneumonia, septicemia, and central nervous system (CNS) infections, such as meningitis. In children with fever caused by HA-MRSA or CA-MRSA infection, HA-MRSA showed a longer duration of fever, for 10.5 days. C-reactive protein (CRP) level caused by HA-MRSA (63.00 mg/L) was higher than CA-MRSA (9.50 mg/L) , and there were statistically significant differences between the groups (t = 2.5670, P < 0.05). However, there were no statistically significant differences between the groups in white blood cell count (WBC) or procalcitonin (PCT) level. (4) Among 37 MRSA isolates, the whole isolates were mecA gene positive (100%). SCCmec genotyping results showed that the most frequent SCCmec types were type III, 17 isolates, the others including type IV 8 isolates, type II1 isolates, nontypable 11 isolates, type I and type V were not found in this group. Therein, among 21 HA-MRSA isolates, SCCmec III was the most common, 15 isolates, type IV 1 isolates, nontypable 5 isolates; among 16 CA-MRSA isolates, SCCmec type IV was the most common, 7 isolates, type III 2 isolates, type II 1 isolate, nontypable 6 isolates. (5) Among the 37 MRSA isolates, 28 were PVL gene positive; and among 21 HA-MRSA isolates, 17 were PVL gene positive; Among 16 CA-MRSA isolates, 11 were PVL gene positive; There were no statistically significant differences between the groups (χ(2) = 0.735, P > 0.05) .

CONCLUSIONCompared with CA-MRSA, HA-MRSA infection was more aggressive, and induced higher C reactive protein; the dominant epidemic strains of CA-MRSA was SCCmec type IV, and HA-MRSA was SCCmec type III; the positive rate of PVL gene was high.

Adolescent ; Anti-Bacterial Agents ; pharmacology ; Bacterial Proteins ; genetics ; Bacterial Toxins ; genetics ; Bacterial Typing Techniques ; Child ; Child, Preschool ; China ; epidemiology ; Cohort Studies ; Community-Acquired Infections ; epidemiology ; microbiology ; Cross Infection ; epidemiology ; microbiology ; DNA, Bacterial ; genetics ; Female ; Genotype ; Humans ; Infant ; Infant, Newborn ; Male ; Methicillin ; pharmacology ; Methicillin Resistance ; genetics ; Methicillin-Resistant Staphylococcus aureus ; classification ; genetics ; isolation & purification ; Penicillin-Binding Proteins ; Staphylococcal Infections ; epidemiology ; microbiology