The purpose of this study was to develop pneumococcal typing by multiplex PCR and compare it with conventional serotyping by quellung reaction. Pneumococcal strains used in this study included 77 isolates from clinical specimens collected from children at Seoul National University Children's Hospital from 2006 to 2010. These strains were selected as they represented 26 different serotypes previously determined by quellung reaction. Molecular type was determined by 8 sequential multiplex PCR assays. Bacterial DNA extracted from cultured colonies was used as a template for PCR, and primers used in this study were based on cps operon sequences. Types 6A, 6B, 6C, and 6D were assigned based on the presence of wciNbeta and/or wciP genes in 2 simplex PCRs and sequencing. All 77 isolates were successfully typed by multiplex PCR assays. Determined types were as follows: 1, 3, 4, 5, 6A, 6B, 6C, 6D, 7C, 7F, 9V, 10A, 11A, 12F, 13, 14, 15A, 15B/15C, 19A, 19F, 20, 22F, 23A, 23F, 34, 35B, and 37. The results according to the PCR assays were in complete concordance with those determined by conventional quellung reaction. The multiplex PCR assay is highly reliable and potentially reduces reliance upon conventional serotyping.
Child ; DNA Primers/chemistry/metabolism ; DNA, Bacterial/chemistry/genetics ; Humans ; Multiplex Polymerase Chain Reaction ; Pneumococcal Infections/microbiology ; Serotyping ; Streptococcus pneumoniae/*classification/genetics/isolation & purification

This study was performed to measure early changes in the serotype distribution of pneumococci isolated from children with invasive disease during the 3-year period following the introduction of 10- and 13-valent pneumococcal conjugate vaccines (PCVs) in Korea. From January 2011 to December 2013 at 25 hospitals located throughout Korea, pneumococci were isolated among children who had invasive pneumococcal disease (IPD). Serotypes were determined using the Quellung reaction, and the change in serotype distribution was analyzed. Seventy-five cases of IPD were included. Eighty percent of patients were aged 3-59 months, and 32% had a comorbidity that increased the risk of pneumococcal infection. The most common serotypes were 19A (32.0%), 10A (8.0%), and 15C (6.7%). The PCV7 serotypes (4, 6B, 9V, 14, 18C, 19F, 23F, and 6A) accounted for 14.7% of the total isolates and the PCV13 minus PCV7 types (1, 3, 5, 7F and 19A) accounted for 32.0% of the total isolates. Serotype 19A was the only serotype in the PCV13 minus PCV7 group. The proportion of serotype 19A showed decreasing tendency from 37.5% in 2011 to 22.2% in 2013 (P = 0.309), while the proportion of non-PCV13 types showed increasing tendency from 45.8% in 2011 to 72.2% in 2013 (P = 0.108). Shortly after the introduction of extended-valent PCVs in Korea, serotype 19A continued to be the most common serotype causing IPD in children. Subsequently, the proportion of 19A decreased, and non-vaccine serotypes emerged as an important cause of IPD. The impact of extended-valent vaccines must be continuously monitored.
Adolescent ; Bacteremia/complications/diagnosis ; Child ; Child, Preschool ; Female ; Hospitals ; Humans ; Infant ; Male ; Pneumococcal Infections/microbiology/*prevention & control ; Pneumococcal Vaccines/*immunology ; Republic of Korea ; Serotyping ; Streptococcus pneumoniae/*classification/isolation & purification ; Vaccines, Conjugate/*immunology

We investigated serotype distribution and antimicrobial resistance of pneumococcal carriage isolates from children after optional immunization with the 7-valent pneumococcal conjugate vaccine (PCV7) in Korea. From June 2009 to June 2010, 205 (16.5%) pneumococcal isolates were obtained from 1,243 nasopharyngeal aspirates of infants and children at Seoul National University Children's Hospital, Korea. Serotype was determined by Quellung reaction and antibiotic susceptibility was tested by E-test. The results were compared to previous studies done in the pre-PCV7 period. In this study, the most common serotypes were 6A (15.3%), 19A (14.7%), 19F (10.2%), 35B (7.3%), and 6D (5.6%). The proportion of PCV7 serotypes decreased from 61.9% to 23.8% (P < 0.001). The overall penicillin nonsusceptibility rate increased from 83.5% to 95.4% (P = 0.001). This study demonstrates the impact of optional PCV7 vaccination in Korea; the proportion of all PCV7 serotypes except 19F decreased while antimicrobial resistant serotypes 6A and 19A further increased.
Anti-Bacterial Agents/pharmacology ; Child, Preschool ; Drug Resistance, Bacterial/drug effects ; Humans ; Infant ; Microbial Sensitivity Tests ; Nasopharynx/*microbiology ; Pneumococcal Infections/immunology/prevention & control ; Republic of Korea ; Serotyping ; Streptococcus pneumoniae/classification/*isolation & purification ; Vaccination ; Vaccines, Conjugate/*immunology

OBJECTIVETo study the clinical characteristics of Streptococcus pneumonia-associated hemolytic uremic syndrome (SP-HUS) in children.

METHODClinical and laboratory data of a pediatric case of SP-HUS were retrospectively analyzed and the key points of diagnosis and therapy were reviewed.

RESULTAn 18-month old girl was admitted with chief complaint of fever and cough for 5 days combined with mild labored breath. Breath sound was found weakened in right lung with lower lobe dullness on percussion. Laboratory tests revealed: WBC 3.7×10(9)/L, Hb 83 g/L, PLT 11×10(9)/L, C-reactive protein (CRP) > 180 mg/L. Morphological study of the RBCs showed marked anisocytosis and schistocytosis. Urinalysis showed 42.66 RBCs per high-power field, occult blood (+++), proteinura (++++). Streptococcus pneumoniae was isolated from blood, pleural fluid and sputum. Serotyping with simplified chessboard system was 3. The direct Coombs test was positive. Serum complement levels (C3 and C4) were depressed at 0.699 g/L, 0.064 g/L, respectively. Chest X-ray showed pleural effusion and infection of the right hemothorax. The computerized tomographic scan of the chest revealed pneumatoceles in the right lower lobe. The diagnosis on admission we considered was SP-HUS. Intravenous antibiotic therapy (vancomycin + cefoperazone/sulbactam) was administered. The renal replacement theraphy was administered to maintain electrolyte and fluid balances and adequate nutrition. Transfusions of washed red blood cells were administered to correct the anemia. One month after admission the patient was good with recovery. Liver and renal function recovered and the pneumonia was resolving, anemia and platelets were corrected. The direct Coombs test turned to be negative. Serum complement levels (C3 and C4) were normal. After 3-month follow-up, no clinical anomalies were detected.

CONCLUSIONSP-HUS should be suspected when the following occurs in the context of pneumococcal infections: microangiopathic hemolytic anemia, thrombocytopenia, acute renal failure and a positive Coombs test result. Serotype 3 of SP was associated with HUS.

Anti-Bacterial Agents ; therapeutic use ; Biomarkers ; analysis ; Coombs Test ; Female ; Hemolytic-Uremic Syndrome ; diagnosis ; etiology ; microbiology ; therapy ; Humans ; Infant ; Lung ; diagnostic imaging ; pathology ; Pleural Effusion ; etiology ; Pneumococcal Infections ; complications ; Radiography ; Retrospective Studies ; Serotyping ; Streptococcus pneumoniae ; classification ; isolation & purification

OBJECTIVETo investigate nasopharyngeal carriage rate, antimicrobial resistance and serotype distribution of Streptococcus pneumoniae among children with upper respiratory infection.

METHODSNasopharygeal swabs were collected from children with upper respiratory infection visiting the outpatient department of Beijing Children′s Hospital between March 2013 and February 2014. The antibiotic susceptibility was tested by Etest method, and the serotype was determined by Quellung reaction.

RESULTSThe nasopharyngeal carriage rate for Streptococcus pneumoniae was 23.8% (699/2 941). One hundred isolates were randomly chosen for antimicrobial susceptiblity test and serotyping. Up to 98.0% isolates were susceptible to parenteral penicillin. The susceptible rate against oral penicillin, however, was 33.0%. The non-susceptible rate to erythromycin and azithromycin was 97.0%. The multi-drug resistance rate was up to 86.0%. The common serotypes were 6A(12.0%), 19F(12.0%), 6B(10.0%), 23F(9.0%) and 14(8.0%). The coverage rates of 7-, 10- and 13-valent pneumococcal conjugate vaccine were 41.0%, 42.0% and 59.0% respectively.

CONCLUSIONSAbout 25% of children with upper respiratory infection are nasopharyngeal colonized by Streptococcus pneumoniae. The isolates show a high antimicrobial resistance. The 13-valent pneumococcal conjugate vaccine covers about 60.0% of the isolates.

Adolescent ; Carrier State ; epidemiology ; microbiology ; Child ; Child, Preschool ; Drug Resistance, Bacterial ; Female ; Humans ; Infant ; Male ; Nasopharynx ; microbiology ; Pneumococcal Vaccines ; immunology ; Respiratory Tract Infections ; microbiology ; Serotyping ; Streptococcus pneumoniae ; classification ; drug effects ; isolation & purification

BACKGROUNDErythromycin-resistant Streptococcus pneumoniae isolates that causing invasive pneumococcal diseases (IPD) in Chinese children remain uncharacterized. This study aims to identify the resistance genes associated with erythromycin resistance and to determine the genetic relationships of IPD isolates in Chinese children.

METHODSA total of 171 S. pneumoniae strains were isolated from 11 medical centers in China from 2006 to 2008. All the isolates were characterized via serotyping and antibiotic susceptibility determination. The erythromycin-resistant isolates were further characterized via ermB and mefA gene detection, multi-locus sequence typing analysis, and pulsed-field gel electrophoresis.

RESULTSA total of 164 (95.9%) isolates showed resistance to erythromycin, of which 162 strains with high high-level resistance (MIC ≥ 256 µg/ml). A total of 104 (63.4%) isolates carry the ermB gene alone, whereas 59 (36.0%) harbor both ermB and mefA genes. Of the 59 strains, 54 were of serotypes 19A and 19F and were identified as highly clonal and related to the Taiwan(19F)-14 clone.

CONCLUSIONSThe erythromycin resistance rate in IPD isolates is significantly high and is predominantly mediated by the ermB gene. Isolates that carry both ermB and mefA genes are predominantly of serotypes 19A and 19F.

Adolescent ; Anti-Bacterial Agents ; pharmacology ; Child ; Child, Preschool ; Drug Resistance, Bacterial ; Electrophoresis, Gel, Pulsed-Field ; Erythromycin ; pharmacology ; Humans ; Infant ; Multilocus Sequence Typing ; Pneumococcal Infections ; microbiology ; Serotyping ; Streptococcus pneumoniae ; classification ; drug effects ; genetics ; isolation & purification

BACKGROUNDDespite the prevalence of Streptococcus pneumoniae serotype 19A, the molecular characteristics of this serotype are yet to be fully elucidated. The aim of this study was therefore to determine the homology of the serotype 19A in China.

METHODSPulsed-field gel electrophoresis and multilocus sequence typing were done to these forty-nine serotype 19A isolates to investigate the relationship between the strains prevalent in Beijing and other regions.

RESULTSFrom 1997 to 2006, the percentage of serotype 19A isolates increased. The susceptibility rate to penicillin and amoxicillin decreased and the resistance rate to cefuroxime increased. ST320 was the most prevalent ST, followed by ST3546. There were six new STs identified in our study. The serotype 19A strains were classified into six different pulsed-field gel electrophoresis (PFGE) patterns. ST320, which was associated with two different PFGE patterns (A and D), accounted for 32 isolates, and ST3546, which was associated with two PFGE patterns (B and E), accounted for eight isolates.

CONCLUSIONSFrom 2003 onwards, ST320 was the most common ST and the rate of resistance to cefuroxime increased significantly. Further long-term surveys of Streptococcus pneumoniae serotype 19A are required to monitor ST prevalence and antimicrobial resistance in this important human pathogen.

Child, Preschool ; China ; Drug Resistance, Bacterial ; Electrophoresis, Gel, Pulsed-Field ; Humans ; Infant ; Infant, Newborn ; Molecular Epidemiology ; Pneumococcal Infections ; drug therapy ; microbiology ; Serotyping ; Streptococcus pneumoniae ; classification ; drug effects ; genetics ; isolation & purification ; Time Factors

The carriage rate and serotype distribution of Streptococcus pneumoniae (S. pneumoniae) in a healthy population in China remains unclear. In this study, we collected the oropharyngeal swabs from 513 individuals in Xinjiang, China. Real-time PCR targeting the lytA gene and 12 serotypes were assessed to identify S. pneumoniae carriage. The total carriage rate of S. pneumoniae was 70.4% (361/513). The most prevalent serotypes were 19B/F, 18B/C, 5, and 6A/B. The highest carriage rate of S. pneumoniae was noted in children aged 6-10 years (88.6%), which merits further attention. The co-colonization rate of two or more S. pneumoniae serotypes was 79.8% (264/331). This study aimed to investigate the baseline pneumococcal carriage rate among healthy individuals in China to improve our understanding of the epidemiology of S. pneumoniae.
Adolescent ; Adult ; Carrier State ; epidemiology ; microbiology ; Child ; Child, Preschool ; China ; epidemiology ; Cross-Sectional Studies ; Female ; Humans ; Infant ; Male ; Middle Aged ; Pneumococcal Infections ; epidemiology ; microbiology ; Prevalence ; Real-Time Polymerase Chain Reaction ; Serogroup ; Streptococcus pneumoniae ; classification ; genetics ; isolation & purification ; Young Adult

OBJECTIVETo investigate the antibiotics-resistance type and molecular epidemiology of Streptococcus pneumoniae isolated from children in Hangzhou.

METHODSThe sensitivities of 323 strains of Streptococcus pneumoniae to 9 antibiotics were determined in vitro by Kirby-Bauer diffuse methods, and MICs of penicillin and cefotaxime were determined by E-test methods.

RESULTSAmong all 323 strains isolated from children during the period from August 2001 to July 2002, 136 strains (42.1%) were sensitive to penicillin, while 57 strains (17.7%) were penicillin-resistant. Penicillin MICs ranged from 0.012 microg/ml to 4.0 microg/ml. All the strains were sensitive to cefotaxime and its MICs ranged from 0.012 microg/ml to 4.0 microg/ml. The most resistant antibiotic was erythromycin and it's resistant-rate was as high as 90.7%, followed by tetracycline (87.6%), trimethoprim-sulfamethoxazole (48.6%) and chloromycetin (14.9%). Totally 197 strains (61.0%) were multi-drug-resistant pneumococci and most of them were resistant to trimethoprim-sulfamethoxazole, erythromycin and tetracycline at the same time. Two strains (0.6%) were resistant to rifampin and none was resistant to vancomycin and ofloxacin. BOX PCR typing was carried out and no overwhelming fingerprinting pattern was found among penicillin resistant Streptococcus pneumoniae strains which were isolated from patients, while the banding patterns were always similar or identical among the strains isolated from the same specimen or from the same patient at different time, respectively.

CONCLUSIONThe antibiotics-resistant rate of pneumococci was high in Hangzhou, but the third-generation cephalosporins were still the best antibiotics against Streptococcus pneumoniae. One child could be infected or colonized by more than one pneumococci clone at the same or different time.

Anti-Bacterial Agents ; pharmacology ; therapeutic use ; Cefotaxime ; pharmacology ; therapeutic use ; Child, Preschool ; China ; Chloramphenicol ; pharmacology ; therapeutic use ; Drug Resistance, Bacterial ; drug effects ; Erythromycin ; pharmacology ; therapeutic use ; Female ; Humans ; Infant ; Male ; Microbial Sensitivity Tests ; Ofloxacin ; pharmacology ; therapeutic use ; Penicillins ; pharmacology ; therapeutic use ; Pneumococcal Infections ; drug therapy ; microbiology ; Respiratory Tract Infections ; drug therapy ; microbiology ; Rifampin ; pharmacology ; therapeutic use ; Streptococcus pneumoniae ; classification ; drug effects ; isolation & purification ; Tetracycline ; pharmacology ; therapeutic use ; Trimethoprim ; pharmacology ; therapeutic use