[Show abstract][Hide abstract] ABSTRACT: To investigate the serotypes, antibiotic susceptibilities, and multi-locus sequence type (MLST) profiles of Streptococcus agalactiae (S. agalactiae) in Beijing to provide references for the prevention and treatment of S. agalactiae infections.
All isolates were identified using the CAMP test and the latex-agglutination assay and serotyped using a Strep-B-Latex kit, after which they were assessed for antibiotic susceptibility, macrolide-resistance genes, and MLST profiles.
In total, 56 S. agalactiae isolates were identified in 863 pregnant women (6.5%). Serotypes Ia, Ib, II, III, and V were identified, among which types III (32.1%), Ia (17.9%), Ib (16.1%), and V (14.3%) were the predominant serotypes. All isolates were susceptible to penicillin and ceftriaxone. The nonsusceptiblity rates measured for erythromycin, clarithromycin, azithromycin, telithromycin, clindamycin, tetracycline, and levofloxacin were 85.7%, 92.9%, 98.2%, 30.4%, 73.2%, 91%, and 39.3%, respectively. We identified 14 sequence types (STs) for the 56 isolates, among which ST19 (30.4%) was predominant. The rate of fluoroquinolone resistance was higher in serotype III than in the other serotypes. Among the 44 erythromycin-resistant isolates, 32 (72.7%) carried ermB.
S. agalactiae isolates of the serotypes Ia, Ib, III, and V are common in Beijing. Among the S. agalactiae isolates, the macrolide and clindamycin resistance rates are extremely high. Most of the erythromycin-resistant isolates carry ermB.
PLoS ONE 03/2015; 10(3):e0120035. DOI:10.1371/journal.pone.0120035 · 3.23 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Group B Streptococcus (GBS) is responsible for two distinct clinical syndromes in the newborn period categorised as either early- or late-onset GBS disease. Maternal GBS colonization of gastrointestinal tract or vaginal is the major risk factor for GBS diseases. There are two main strategies for identifying women at risk of giving birth to a GBS-infected infant: universal screening strategy and risk-based assessment. In the United States and other countries, the implementation of maternal intrapartum antibiotic prophylaxis policies has significantly reduced the incidence of early-onset neonatal GBS disease, but has little effect on the incidence of late-onset GBS disease. Penicillin is the first choice for antibiotic prophylaxis treatment. GBS strains which are isolated from pregnant women who are allergic to penicillin should undergo antibiotic susceptibility testing. Antibiotic prophylaxis measures have some disadvantages, so researchers should actively develop other precautions to prevent GBS infection.
[Show abstract][Hide abstract] ABSTRACT: To investigate nasopharyngeal carriage rate, antimicrobial resistance and serotype distribution of Streptococcus pneumoniae among children with upper respiratory infection.
[Show abstract][Hide abstract] ABSTRACT: Globally, pneumonia is the leading cause of childhood mortality. Pneumonia is the second killer of children less than 5 years of age in China. The World Heath Organization and United Nations Children′s Fund launched the integrated Global Action Plan for the Prevention and Control of Pneumonia and Diarrhea (GAPPD) in 2013. The ambitious goal is to end preventable childhood deaths due to pneumonia by 2025. Countries or regions should achieve the following goals: (1) reduce mortality from pneumonia in children less than 5 years of age to fewer than 3 per 1 000 live births; (2) reduce the incidence of severe pneumonia by 75% in children less than 5 years of age compared to 2010 levels. If the implementation of key interventions is accelerated, the mortality rate of childhood pneumonia will drop substantially every year, which makes the goal achievable.
[Show abstract][Hide abstract] ABSTRACT: Several fatal events occurred in Hunan, Guangdong and Sichuan Province in December, 2013. The events were reported by the news media, which followed growing public concern. Currently, more and more vaccines were developed and the immunization was adopted for more objectives. The clinicians, especially pediatricians will face a growing number of clinical problems related to the vaccine. The clinicians should pay attention to learn more knowledge about vaccines. This article describes the definition and classification of "adverse events following immunization" and "serious vaccine product-related reactions", and the signifcance and conclusion of causality assessment following immunization.
Zhongguo dang dai er ke za zhi = Chinese journal of contemporary pediatrics 01/2014; 16(1):1-4.
[Show abstract][Hide abstract] ABSTRACT: Erythromycin-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.
A 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.
A 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.
The 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.
Chinese medical journal 04/2013; 126(8):1522-7. DOI:10.3760/cma.j.issn.0366-6999.20122185 · 1.02 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Background
Streptococcus pneumoniae is the main pathogen that causes respiratory infections in children younger than five years. The increasing incidence of macrolide- and tetracycline-resistant pneumococci among children has been a serious problem in China for many years. The molecular characteristics of erythromycin-resistant pneumococcal isolates that were collected from pediatric patients younger than five years in Beijing in 2010 were analyzed in this study.
A total of 140 pneumococcal isolates were collected. The resistance rates of all isolates to erythromycin and tetracycline were 96.4% and 79.3%, respectively. Of the 135 erythromycin-resistant pneumococci, 91.1% were non-susceptible to tetracycline. In addition, 30.4% of the erythromycin-resistant isolates expressed both the ermB and mef genes, whereas 69.6% expressed the ermB gene but not the mef gene. Up to 98.5% of the resistant isolates exhibited the cMLSB phenotype, and Tn6002 was the most common transposon present in approximately 56.3% of the resistant isolates, followed by Tn2010, with a proportion of 28.9%. The dominant sequence types (STs) in all erythromycin-resistant S. pneumoniae were ST271 (11.9%), ST81 (8.9%), ST876 (8.9%), and ST320 (6.7%), whereas the prevailing serotypes were 19F (19.3%), 23F (9.6%), 14 (9.6%), 15 (8.9%), and 6A (7.4%). The 7-valent pneumococcal conjugate vaccine (PCV7) and 13-valent pneumococcal conjugate vaccine (PCV13) coverage of the erythromycin-resistant pneumococci among the children younger than five years were 45.2% and 62.2%, respectively. ST320 and serotype 19A pneumococci were common in children aged 0 to 2 years. CC271 was the most frequent clonal complex (CC), which accounts for 24.4% of all erythromycin-resistant isolates.
The non-invasive S. pneumoniae in children younger than five years in Beijing presented high and significant resistance rates to erythromycin and tetracycline. The expressions of ermB and tetM genes were the main factors that influence pneumococcal resistance to erythromycin and tetracycline, respectively. Majority of the erythromycin-resistant non-invasive isolates exhibited the cMLSB phenotype and carried the ermB, tetM, xis, and int genes, suggesting the spread of the transposons of the Tn916 family. PCV13 provided higher serotype coverage in the childhood pneumococcal diseases caused by the erythromycin-resistant isolates better than PCV7. Further long-term surveys are required to monitor the molecular characteristics of the erythromycin-resistant S. pneumoniae in children.
[Show abstract][Hide abstract] ABSTRACT: To investigate the molecular characteristics of methicillin-resistant Staphylococcus aureus (MRSA) isolates from Chinese children in seven cities.
A total of 134 MRSA isolates were collected from nine hospitals. Multilocus sequence typing and spa typing were analyzed by polymerase chain reaction (PCR), and staphylococcal chromosomal cassette mec (SCCmec) type was analyzed by multiplex PCR. The Panton-Valentine leukocidin (pvl) gene was also detected.
Most MRSA strains were isolated from pneumonia and skin and soft tissue infection (SSTIs) patients, accounting for 82.1%. Overall, 16 sequence types (STs) were obtained, and CC59 (51.7%) was found to be the most prevalent, which included ST 59 and ST 338, followed by ST239 (16.4%). SCCmec types II, III, IV, and V were also identified in the current study. SCCmec type IV was the most predominant type at 50.0%, followed by SCCmec type V at 23.9% and III at 23.9%. SCCmec subtypes IVa, IVc, and IVg were found among SCCmec type IV strains, whereas IVa was the main subtype at 77.6%. Twenty-six spa types were also identified, among which the predominant type was t437 (47.8%). The prevalence of pvl genes and the SCCmec type of strain was relevant, and the pvl gene positive rate was higher in SCCmec type IV and V-type strains than in SCCmec type II and III strains (58.6% vs. 14.3%, P < 0.05); there was a significant difference between them. In the strains isolated from pneumonia and SSTIs, ST59-MRSA-IVa(t437) was the predominant clone. There were five clones detected from the strains isolated from septicemia, with ST59-MRSA-IVa(t437) and ST59-MRSA-V(t437) as the main clones (57.1%). Various predominant clones existed in different regions. ST59-MRSA-IVa(t437) was the prevalent clone in the Guangzhou, Beijing, Chongqing, and Shenzhen areas, whereas ST239-MRSA-III(t037) was the prevalent clone in the Shanghai area. Fifty percent of the isolates from the Wenzhou area belonged to ST910-MRSA-V(t318), whereas three clinical strains isolated from the Shenyang region belonged to three different types.
The results indicate that MRSA isolates from Chinese children are largely associated with the ST59-MRSA-IV(t437) and ST239-MRSA-III(t037) clones. These two may belong to community-acquired MRSA and hospital-acquired ones, respectively. Different prevalent clones were detected in different diseases and different regions. Therefore, there is a need to conduct further research on clinical isolates, which can guide the choice of antibiotic treatment and the examination of MRSA prevalence.
Zhonghua er ke za zhi. Chinese journal of pediatrics 01/2012; 50(1):38-44.
[Show abstract][Hide abstract] ABSTRACT: In the present study, the serotype distribution and antibiotic resistance of S. pneumoniae from pediatric patients with upper respiratory infections in Beijing, 2010 were described. 140 pneumococcal isolates were obtained, and the prevailing five serotypes were 19F (18.6%), 23F (9.3%), 14 (9.3%), 15 (9.3%), and 6A (7.1%). The vaccine coverage of PCV7, PCV10, and PCV13 were 43.6%, 43.6%, and 60.0%, respectively. According to the CLSI 2010 criteria, 99.3% of the S. pneumoniae isolates were susceptible to penicillin. The resistance rates to erythromycin and azithromycin were 96.4% and 97.1%, respectively. Meanwhile, 64.3% (90/140) of all pneumococcal isolates were multidrug-resistant S. pneumoniae (MDRSP). PCV13 covered 68.9% (62/90) of MDRSP strains, whereas it was 47.8% (43/90) for PCV7. ErmB was the dominant macrolide-resistance gene, whereas 30.4% pneumococcal isolates expressed both ermB and mefA. No isolate expressed ermTR. The potential coverage of PCV13 is higher than PCV7 and PCV10 because high rates of serotypes 6A and 19A, and the conjugate vaccines could prevent the spread of MDRSP. S. pneumoniae is still sensitive to penicillin. The resistance rate of S. pneumoniae to macrolides is high and ermB is the dominant macrolide-resistance gene in China, so continued surveillance of the antimicrobial susceptibility of S. pneumoniae may be necessary.
[Show abstract][Hide abstract] ABSTRACT: The recently determined serotypes 6C and 6D Streptococcus pneumoniae, as well as subtypes 6B-I and 6B-II, were not reported in China. Among the 171 invasive isolates, 19 were identified as serogroup 6. There were equal distribution (42.1%) of 6B-I and 6B-II, 15.8% of 6A and lack of 6C and 6D. Among 1662 noninvasive isolates, 210 were identified as serogroup 6. The rates of types 6A, 6B-I, 6B-II, 6C, and 6D were 42.4%, 21.0%, 29.1%, 4.8%, and 2.9%, respectively. Subtype 6B-II was more resistant to antibiotics than others. The main sequence types (STs) of serotype 6C and 6D isolates were ST2912 and ST982, respectively. These results suggested that all recognized types of serogroup 6 can be found in China and that subtype 6B-II was more drug resistant. The epidemic STs of serotype 6C and 6D did not show genetic association with the STs spreading in other countries.
[Show abstract][Hide abstract] ABSTRACT: Despite 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.
Pulsed-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.
From 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.
From 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.
Chinese medical journal 06/2011; 124(12):1769-74. DOI:10.3760/cma.j.issn.0366-6999.2011.12.002 · 1.02 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: A prospective study was performed to determine serotype distribution and antimicrobial resistance in Streptococcus pneumoniae (S. pneumoniae) from Chinese children <5 years old meeting pneumonia criteria. A total of 3865 children were enrolled and 338 S. pneumoniae isolates were obtained. The most frequent serotypes were 19F (55.6%), 19A (13.9%), 23F (10.1%), 6B (4.7%), and 14 (3.6%). The 7-, 10- and 13-valent conjugate vaccines, respectively, covered 76.3%, 76.9%, and 92.3% of isolates. Out of the isolates, six (1.8%) were penicillin resistant. All except 1 of the isolates were resistant to erythromycin. Serotype 19A showed the highest drug resistance. The use of PCV7 has the potential to prevent a substantial number of pneumococcal infections. However, PCV13 is likely to prevent more episodes of pneumococcal disease in China because of the high rates of 19A.
[Show abstract][Hide abstract] ABSTRACT: In this study, 68 group A streptococcus (GAS) isolates associated with two outbreaks of acute glomerulonephritis (AGN) in China were analyzed by emm typing. A total of 11 different emm types were identified. Analysis of emm type distribution suggested that AGN outbreaks in two counties were caused by emm60.1- and emm63.0-type GAS. These two types were further characterized by pulsed-field gel electrophoresis, multilocus sequence typing, sof sequence typing, and PCR-based identification of streptococcal pyrogenic exotoxin A, B, and C (speA, speB, and speC) genes. In antimicrobial susceptibility tests, all outbreak strains were resistant to erythromycin and tetracycline, and the rates of resistance of nonoutbreak strains to the two antibiotics were 63.6% and 90.9%. This study is also the first to report a nephritogenic M63 GAS strain.
[Show abstract][Hide abstract] ABSTRACT: To analyze the antibiotic resistance of the Pseudomonas aeruginosa (PA) isolated from pediatric patients and the resistant genes of beta-lactam antibiotics thereof.
146 PA strains were isolated from pediatric patients. Agar dilution method recommended by the Clinical and Laboratory Standards Institute was used to examine the minimum inhibitory concentrations (MICs) of 12 antimicrobial agents, including the penicillins, third and fourth genet ration cephalosporins, carbapenemase, Aztreonam, beta-lactamase inhibitors, quinolones, and aminoglycosides. PCR was used to detect the expression of the genes TEM, SHV, OXA, PER, GES, CTX-M, IMP, VIM, DHA, MIR, FOX, and oprD2.
The multi-drug resistance rates against different antibiotic were high among the 146 PA strains. The rates of imipenem and meropenem resistance were 41.1% and 35.6% respectively. Among the 146 PA strains, 46 (31.5%) were positive for the MBL genotype; 38 (82.6%) carried the blaIMP gene, 8 (17.4%) carried the blaVIM gene, and 114 (78.1%) were oprD2 negative. The genes TEM, SHV, OXA, CTX-M, PER, VEB, GES, FOX, MIR, and DHA were not found in all strains.
Many PA isolated from pediatric patients carry the genes IMP or VIM and losses oprD2 gene related to the expression of the outer membrane porin OprD2. The loss of the gene oprD2 is essential mechanism of beta-lactam antibiotics resistance in PA.
[Show abstract][Hide abstract] ABSTRACT: In the present study, we characterized multidrug-resistant Pseudomonas aeruginosa (MDRP) clinical isolates from a paediatric facility and investigated the types and features of the metallo-beta-lactamases (MBLs) produced by carbapenem-resistant strains.
Four hundred and ninety-eight strains of Pseudomonas aeruginosa were isolated from patients at Beijing Children's Hospital between January 2005 and December 2006. The minimal inhibition concentrations (MICs) of the strains for 13 antibiotics were measured. A combination of the E test and PCR amplification/DNA sequencing was used to define the carbapenem-resistant strains.
We found that 24.1% (120/498) of the isolates were MDRP. The frequencies of resistance to imipenem and meropenem were 34.2% and 35.8%, respectively, and the MIC50 and MIC90 values for the two antibiotics were identical at 4 microg/ml and 32 microg/ml, respectively. The detection rate for carbapenem resistance was 49.2% (59/120). Among the 59 carbapenem-resistant Pseudomonas aeruginosa strains, 39 (66.1%) were positive for the MBL genotype; 35 (89.7%) strains carried the bla(IMP) gene and 4 (10.3%) strains carried the bla(VIM) gene. Neither bla(SPM) nor bla(GIM) was amplified from any of the 59 isolates. DNA sequencing revealed that IMP-1 was present in 35 IMP-producing isolates and VIM-2 was detected in four VIM-producing isolates.
These MDRP isolates exhibited high frequencies of resistance to carbapenems among clinical isolates from a paediatric facility in Beijing, China. The production of MBL appears to be an important mechanism for carbapenem resistance in Pseudomonas aeruginosa.
Chinese medical journal 10/2008; 121(17):1611-6. · 1.02 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: This review describes major contributions to our understanding of pneumococcal diseases among children in hinterland of China. The data demonstrated that Streptococcus pneumoniae (S. pneumoniae) is an important pathogen of pyogenic meningitis, pneumonia, and other infectious diseases in children. The distribution of serotypes of S. pneumoniae showed great diversity in several studies in various cities during different years. The penicillin nonsusceptibility rates, although variable, demonstrated an increase over time in China. The prevalence of resistance to erythromycin, trimethoprim-sulfamethoxazole or tetracycline was reported to be over 80% and exceeded those reported from other developed countries. A national survey on serotype prevalence, antimicrobial resistance and molecular epidemiology of S. pneumoniae, especially in invasive pneumococcal diseases, and studies to determine pneumococcal disease burden should be undertaken in the future to provide evidence and guidance to the use of vaccine and antibiotics in S. pmeumoniae infections.
[Show abstract][Hide abstract] ABSTRACT: To investigate the antimicrobial resistance of Streptococcus pneumoniae (S.pneumoniae) isolated from Chinese children with pneumonia.
Hypopharyngeal aspirate specimens were collected from hospitalized children with pneumonia who were admitted to the children's hospital located in Beijing, Shanghai, Guangzhou or Shanghai from February 16, 2006 to February 16, 2007. The minimum inhibitory concentration (MIC) of S.pneumoniae isolates against penicillin, amoxicillin, cefuroxime (sodium), ceftriaxone, erythromycin, vancomycin, ofloxacin and imipenem was determined by E-test method.
A total of 279 S.pneumoniae isolates were obtained. Eighty-six percent of the isolates were not susceptive to penicillin, and 23.3% was resistant to penicillin. The rate of susceptibility of the isolates to amoxicillin was 92.1%, and to cefuroxime and ceftriaxone was 19.0% and 75.3%, respectively. The isolates also showed a high susceptibility to vancomycin (99.6%) and ofloxacin (97.8%). Seventeen point six percent of the isolates were not susceptive to imipenem, and most of those were intermediate. Almost of all isolates were resistant to erythromycin. There were some distinct regional differences in the susceptibility to antimicrobials tested except for erythromycin, vancomycin and ofloxacin.
The S.pneumoniae isolates from Chinese children with pneumonia were susceptive to amoxicillin, vancomycin and ofloxacin, but were not susceptive or resistant to penicillin, cefuroxime and erythromycin. The isolates kept susceptibility to ceftriaxone and imipenem to a certain extent.
Zhongguo dang dai er ke za zhi = Chinese journal of contemporary pediatrics 07/2008; 10(3):275-9.