OBJECTIVETo investigate the epidemiological characteristics of respiratory syncytial virus (RSV) subtypes and genotypes in southern Zhejiang province, and to determine whether RSV genotypes are correlated with the disease severity of lower respiratory tract infection (LRTI).

METHODNasopharyngeal secretions (NPS) from children under 5 years of age who were hospitalized with LRTI during 5 consecutive seasons from July 1, 2009 to June 30, 2014 were collected. RSV antigen was determined using direct immunofluorescence (DIF). Two hundred strains of RSV were randomly selected from each epidemic season. RNA was extracted and identified as subtype A or B by using reverse transcription-polymerase chain reaction (RT-PCR), and randomly selected strains of the full length attachment (G) genes of both subtype A and subtype B were amplified by PCR and sequencing. Clinical data were collected, and the disease severity between different genotypes were compared simultaneously.

RESULTOf the total 1 000 randomly selected RSV positive samples, 462 (46.2%) and 538 (53.8%) samples were identified as subtype A and B, respectively. It was found that subtype B predominated in the 2009-2010 and 2012-2014 epidemic seasons and subtype A in 2010-2012 epidemic seasons. A total of 112 strains of complete sequences of G genes were obtained, including four subtype A genotypes NA1, NA4, GA2 and ON1, and six subtype B genotypes BA8-10, BA-C, CB1, and GB2. Phylogenetic analysis revealed that 39/52 (75.0%) subtype A strains were classified as NA1 genotype, followed by ON1 genotype (10/52,19.2%) and 44/60 (73.3%) subtype B strains were classified as BA9 genotype, followed by BA8 genotype (6/60,10.0%). BA9 was the predominant genotype among subtype B except 2010-2011 epidemic season, while NA1 was the predominant genotype among subtype A except 2013-2014 epidemic season. Only ON1 and BA9 genotypes were checked out during 2013-2014 epidemic season. There was statistically significant difference in the average severity score of illness in 39 cases infected with NA1 genotype (4.154) and 44 cases of BA9 genotype (3.341) (U=642.500, P<0.05). Furthermore, in the rate of oxygen uptake, the percentage of those infected with NA1 genotype (33.3%) was higher than those infected with BA9 genotype (13.6%) (χ2=4.544, P<0.05). However, there were no significant difference in the age, clinical symptoms, the percentage of intensive care unit admission, length of hospitalization and the outcome of the disease between NA1 and BA9 infection.

CONCLUSIONThe shift of predominant RSV subtype from 2009 to 2014 were B-A-A-B-B in the southern areas of Zhejiang province. Multiple genotypes co-circulated during five RSV epidemic seasons. NA1 and BA9 genotypes were the predominant genotypes of subtype A and B, respectively. Compared with infection with BA9 genotype, NA1 genotype infection was associated with more severe disease and proportion of patients needed oxygen therapy was higher.

Child, Preschool ; China ; epidemiology ; Genotype ; Hospitalization ; Humans ; Infant ; Nasopharynx ; Phylogeny ; Polymerase Chain Reaction ; Respiratory Syncytial Virus Infections ; epidemiology ; Respiratory Syncytial Virus, Human ; genetics ; Respiratory Tract Infections ; epidemiology ; Seasons

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