Infantile Pertussis Rediscovered in China

Immunization against pertussis was introduced in China in the 1960s. Since the 1970s, no culture-confirmed pertussis cases have been reported in the country. We report six infants with culture-confirmed pertussis, who were initially diagnosed as having other respiratory diseases, at Beijing Children’s Hospital, Beijing

Presence of qnr gene in Escherichia coli and Klebsiella pneumoniae resistant to ciprofloxacin isolated from pediatric patients in China

<p>Abstract</p> <p>Background</p> <p>Quinolone resistance in <it>Enterobacteriaceae </it>results mainly from mutations in type II DNA topoisomerase genes and/or changes in the expression of outer membrane and efflux pumps. Several recent studies have indicated that plasmid-mediated resistance mechanisms also play a significant role in fluoroquinolone resistance, and its prevalence is increasing worldwide. In China, the presence of the <it>qnr </it>gene in the clinical isolates of <it>Enterobacteriaceae </it>has been reported, but this transmissible quinolone resistance gene has not been detected in strains isolated singly from pediatric patients. Because quinolones associated with a variety of adverse side effects on children, they are not authorized for pediatric use. This study therefore aimed to investigate the presence of the <it>qnr </it>gene in clinical isolates of <it>E. coli </it>and <it>K. pneumoniae </it>from pediatric patients in China.</p> <p>Methods</p> <p>A total 213 of non-repetitive clinical isolates resistant to ciprofloxacin from <it>E. coli </it>and <it>K. pneumoniae </it>were collected from hospitalized patients at five children's hospital in Beijing, Shanghai, Guangzhou, and Chongqing. The isolates were screened for the plasmid-mediated quinolone resistance genes of <it>qnrA</it>, <it>qnrB</it>, and <it>qnrS </it>by PCR. Transferability was examined by conjugation with the sodium azide-resistant <it>E. coli </it>J53. All <it>qnr</it>-positive were analyzed for clonality by enterobacterial repetitive intergenic consensus (ERIC)-PCR.</p> <p>Results</p> <p>The study found that 19 ciprofloxacin-resistant clinical isolates of <it>E. coli </it>and <it>K. pneumoniae </it>were positive for the <it>qnr </it>gene, and most of the <it>qnr </it>positive strains were ESBL producers. Conjugation experiments showed that quinolone resitance could be transferred to recipients. Apart from this, different DNA banding patterns were obtained by ERIC-PCR from positive strains, which means that most of them were not clonally related.</p> <p>Conclusion</p> <p>This report on transferable fluoroquinolone resistance due to the <it>qnr </it>gene among <it>E. coli </it>and <it>K. pneumoniae </it>strains indicated that plasmid-mediated quinolone resistance has emerged in pediatric patients in China.</p

Survey of childhood empyema in Asia: Implications for detecting the unmeasured burden of culture-negative bacterial disease

<p>Abstract</p> <p>Background</p> <p>Parapneumonic empyema continues to be a disease of significant morbidity and mortality among children despite recent advances in medical management. To date, only a limited number of studies have assessed the burden of empyema in Asia.</p> <p>Methods</p> <p>We surveyed medical records of four representative large pediatric hospitals in China, Korea, Taiwan and Vietnam using <it>ICD</it>-10 diagnostic codes to identify children <16 years of age hospitalized with empyema or pleural effusion from 1995 to 2005. We also accessed microbiology records of cultured empyema and pleural effusion specimens to describe the trends in the epidemiology and microbiology of empyema.</p> <p>Results</p> <p>During the study period, we identified 1,379 children diagnosed with empyema or pleural effusion (China, n = 461; Korea, n = 134; Taiwan, n = 119; Vietnam, n = 665). Diagnoses of pleural effusion (n = 1,074) were 3.5 times more common than of empyema (n = 305), although the relative proportions of empyema and pleural effusion noted in hospital records varied widely between the four sites, most likely because of marked differences in coding practices. Although pleural effusions were reported more often than empyema, children with empyema were more likely to have a cultured pathogen. In addition, we found that median age and gender distribution of children with these conditions were similar across the four countries. Among 1,379 empyema and pleural effusion specimens, 401 (29%) were culture positive. <it>Staphylococcus aureus </it>(n = 126) was the most common organism isolated, followed by <it>Streptococcus pneumoniae </it>(n = 83), <it>Pseudomonas aeruginosa </it>(n = 37) and <it>Klebsiella </it>(n = 35) and <it>Acinetobacter </it>species (n = 34).</p> <p>Conclusion</p> <p>The age and gender distribution of empyema and pleural effusion in children in these countries are similar to the US and Western Europe. <it>S. pneumoniae </it>was the second leading bacterial cause of empyema and pleural effusion among Asian children. The high proportion of culture-negative specimens among patients with pleural effusion or empyema suggests that culture may not be a sufficiently sensitive diagnostic method to determine etiology in the majority of cases. Future prospective studies in different countries would benefit from standardized case definitions and coding practices for empyema. In addition, more sensitive diagnostic methods would improve detection of pathogens and could result in better prevention, treatment and outcomes of this severe disease.</p

Group B streptococcus capsular polysaccharide - Cholera toxin B subunit conjugate vaccine for mucosal immunisation : development and preclinical evaluation of experimental conjugate vaccines

Group B streptococci (GBS) can colonize the female genital and rectal tracts and cause invasive infection in susceptible newborns. An optimally effective GBS vaccine should induce both mucosal and systemic immunity. We prepared GBS capsular polysaccharide (CPS) - recombinant cholera toxin B subunit (rCTB) conjugate vaccines by different methods and evaluated their systemic and mucosal immunogenicity in mice. Specific IgM, IgG and IgA antibodies to the CPS were tested in serum and IgG and IgA antibodies in lungs, intestinal, rectal and vaginal extracts by ELISA.We found, as tested with GBS type III CPS, that generally CPS III conjugates were superior to unconjugated CPS in eliciting CPS-specific immune responses in serum and mucosal tissue extracts. The conjugates when administrated subcutaneously induced only IgG responses in serum, lung and vagina, while intranasal (i.n.) vaccination also elicited specific anti-CPS IgA responses in the lungs and vagina. A CPS-tetanus toxoid conjugate administrated i.n. induced a strong serum IgG but only a weak mucosal IgA response, while CPS-rCTB conjugates elicited high IgG as well as IgA antibodies in both serum and the lungs after i.n. immunization. Both large and small molecular size fractions of CPS III-rCTB conjugates induced high, almost comparable levels of CPS specific IgG in serum, lungs and vagina that were generally superior to those obtained with a mixture of CPS III and rCTB. However, the smaller conjugates in most cases elicited a lower anti-CPS IgA immune response as compared with the larger conjugates, and the strongest anti-CPS responses in both tissues and serum were obtained with the large fraction of a CPS III-rCTB conjugate prepared by reductive amination.The CPS specific immune responses in various organs were dependent on the route of immunization. Generally, as tested with four routes of mucosal vaccination, including i.n. oral, vaginal and rectal immunizations, the highest levels of IgA and IgG anti-CPS antibody responses were generated in the regions or sites of conjugate exposure. All four mucosal routes also induced antibody responses to CPS in distant mucosal tissues. Rectal vaccination induced high specific IgA in the vagina and the intestine, and oral administration in the lungs and rectum. All four routes of vaccination with the conjugate elicited similar, high levels of anti-CPS IgG in serum. I.n. immunization was usually the most efficient way to obtain strong anti-CPS responses in both serum and mucosal tissues including both the lungs and the vagina.Priming with pure GBS CPS III alone or with GBS CPS III-rCTB conjugate induced comparable levels of specific IgG and IgA in serum, lungs and vagina. However, the mice primed with CPS III and boosted with CPS III-rCTB conjugate by i.n. route failed to produce significant levels of IgG2a, IgG2b and IgG3 in serum in contrast to mice primed with the conjugate, which produced high levels of all these IgG sub-classes. Pre-immunization with rCTB did not suppress specific serum IgG response induced by GBS CPS III-rCTB conjugate intranasally, but did inhibit mucosal IgA responses.I.n. immunization with a combination of CPS type III-rCTB and CPS type Ia-rCTB conjugates was shown to induce anti-CPS III and Ia immune responses in serum and lungs that were fully comparable with the responses to immunization with the monovalent Ia-rCTB or III-rCTB conjugates.These results demonstrate that (1) use of rCTB as a carrier protein for GBS III CPS could markedly improve the mucosal immune response; (2) rectal and vaginal vaccination and slightly less consistently i.n. immunization appear to be the most efficient ways of stimulating local anti-CPS immune responses in the rectal and vaginal tracts; (3) GBS CPS III-rCTB and Ia-rCTB conjugates prepared by reductive amination may serve as a basis for development of effective bivalent or multivalent mucosal vaccines to prevent mucosal colonization and invasive infection caused by GBS

A mesoporous structure for efficient photocatalysts: anatase nanocrystals attached to leached clay layers

Increasing the content of anatase nanocrystals and improving the accessibility of these crystals to reactants (UV photons, organic contaminant molecules and oxygen molecules) will enhance photocatalytic performance. Thus we designed a synthesis approach to achieve such structures. The synthesis involves reaction of clay suspensions with TiOSO4, which leads to formation of anatase nanocrystals attaching to leached clay layers through Ti-O-Si bonds. It is also discovered that the crystal size, the pore size and the specific surface area of the catalysts, can be tailored by manipulating the acidity, the ratio of Ti/clay and the hydrothermal temperature of the synthesis systems. Such a synthesis is different from the conventional approach of pillared intercalated layered clays. The activity of these catalysts for the degradation of phenol was investigated, and we find that the catalytic activity increases with the increasing volume of the pore larger than 3 nm because formation of mesoporous system and anatase nanocrystals leads to improvement in the photocatalytic activity of photocatalysts. This new structure is a more efficient photocatalyst structure for degradating organic pollutant in water, compared to the conventional titania pillared layered clay. The knowledge acquired in this study is useful for designing photocatalysts with high efficiency. (C) 2007 Elsevier Inc. All rights reserved.Increasing the content of anatase nanocrystals and improving the accessibility of these crystals to reactants (UV photons, organic contaminant molecules and oxygen molecules) will enhance photocatalytic performance. Thus we designed a synthesis approach to achieve such structures. The synthesis involves reaction of clay suspensions with TiOSO4, which leads to formation of anatase nanocrystals attaching to leached clay layers through Ti-O-Si bonds. It is also discovered that the crystal size, the pore size and the specific surface area of the catalysts, can be tailored by manipulating the acidity, the ratio of Ti/clay and the hydrothermal temperature of the synthesis systems. Such a synthesis is different from the conventional approach of pillared intercalated layered clays. The activity of these catalysts for the degradation of phenol was investigated, and we find that the catalytic activity increases with the increasing volume of the pore larger than 3 nm because formation of mesoporous system and anatase nanocrystals leads to improvement in the photocatalytic activity of photocatalysts. This new structure is a more efficient photocatalyst structure for degradating organic pollutant in water, compared to the conventional titania pillared layered clay. The knowledge acquired in this study is useful for designing photocatalysts with high efficiency. (C) 2007 Elsevier Inc. All rights reserved

ISSa4-Based Differentiation of Streptococcus agalactiae Strains and Identification of Multiple Target Sites for ISSa4 Insertions

A collection of 113 epidemiologically unrelated Streptococcus agalactiae strains were studied (group B streptococcus; GBS): they belonged to different serotypes and were isolated from pregnant women in China and Russia. The insertion sequence ISSa4 was found in 21 of 113 strains (18,6%). All of the strains with ISSa4 belonged to serotypes II and II/c and were characterized by the presence of IS1381 and IS861 as well as the absence of IS1548 and GBSi1. All of the strains with ISSa4 possessed both bca and bac virulence genes coding for α and β antigens, respectively. Among 21 ISSa4-positive strains, 13 different HindIII patterns (D1 to D13) hybridizing with an ISSa4 probe were found. One of them (D13) contained a single HindIII hybridization fragment 6.5 kb in size that was found to be specific for all ISSa4-positive GBS strains. Multiple target sites for insertions of ISSa4 were identified and included a putative pathogenicity island, “housekeeping” genes, and intergenic regions, as well as the genes for hypothetical proteins. No significant similarity was observed in the sequences of the target genes for ISSa4 insertions, in the relative location of the target genes on the chromosome, or the biological functions of the encoded proteins. The possible significance of ISSa4-based differentiation of the strains and the presence of possible “hot spots” for insertions of ISSa4 in GBS genome are discussed

Ferric ions doped 5A molecular sieves for the oxidation of HCHO with low concentration in the air at moderate temperatures

Zeolitc 5 A molecular sieve was doped with iron ions Fe3+ by ion exchange and the catalytic activity of lie obtained solids for the formaldehyde oxidation was investigated. The catalysts are able to oxidize formaldehyde (if a very low concentration at moderate temperatures, The light-off temperatures were about 70-100 C and the temperatures for the complete oxidation were about 100 190 C,The oxidation reaction product contains HCOOH, and its formation is associated with the silanol groups on the catalyst structure, The pH value of the suspension during the ion exchange and the temperatures at which the catalysts were calcined has profound influence on the amount of the silanols. in the catalysts. Ferric species are also active sites on the zeolite, which are more active at higher temperature than silanols and responsible for producing carbon dioxide. (c) 2005 Elsevier B.V. All rights reserved.Zeolitc 5 A molecular sieve was doped with iron ions Fe3+ by ion exchange and the catalytic activity of lie obtained solids for the formaldehyde oxidation was investigated. The catalysts are able to oxidize formaldehyde (if a very low concentration at moderate temperatures, The light-off temperatures were about 70-100 C and the temperatures for the complete oxidation were about 100 190 C,The oxidation reaction product contains HCOOH, and its formation is associated with the silanol groups on the catalyst structure, The pH value of the suspension during the ion exchange and the temperatures at which the catalysts were calcined has profound influence on the amount of the silanols. in the catalysts. Ferric species are also active sites on the zeolite, which are more active at higher temperature than silanols and responsible for producing carbon dioxide. (c) 2005 Elsevier B.V. All rights reserved