Changes of serotype and genotype in Streptococcus pneumoniae isolates from a Korean hospital in 2007

We investigated the change in clones and serotypes of Streptococcus pneumoniae isolates in a Korean tertiary-care hospital. Serotypes of S. pneumoniae isolates were determined by the capsular quellung method, and in vitro susceptibility testing was performed by broth microdilution method. Multilocus sequence typing was performed to determine the genotypes of the S. pneumoniae isolates. The erm(B) and mef(A) genes in erythromycin-resistant isolates were also detected using the duplex polymerase chain reaction method. During the 2 periods assayed (1998–2000 and 2007), 7-valent pneumococcal conjugate vaccine (PCV7) serotypes decreased significantly from 58.3% to 30.9% (P = 0.001). Especially, serotypes 19F and 23F decreased significantly from 31.7% to 8.5% (P < 0.0001) and from 20.0% to 7.4% (P = 0.021), respectively. In contrast to the other PCV7 serotypes, serotype 14 coupled with CC554 emerged in 2007, which may indicate no effect of PCV7 against serotype 14 isolates from Korea and the possibility of a different subtype. Of the non- PCV7 serotypes, serotype 19A increased from 8.3% to 14.9% (P = 0.227) and serotype 15 increased from 0% to 8.5% (P = 0.023). The increase of serotype 19A was due to the expansion of a preexisting clone with serotype 19A, ST320. However, S. pneumoniae isolates of serotype 15 showed diverse STs. Our data may provide helpful information in local vaccine serotype expansion or replacement in Korea.     

Updates on vaccinating the inflammatory bowel disease patient

Introduction: Many of the therapeutic options for patients with inflammatory bowel disease (IBD) suppress the immune system, which increases the risk of certain infections in these patients. Effective vaccines exist and offer protection against a number of infectious diseases. However, data has shown that IBD patients are inadequately vaccinated and, as a result, are at risk of developing certain preventable infections. Furthermore, gastroenterologists’ knowledge regarding the appropriate immunizations to administer to their IBD patients is suboptimal.

Areas covered: Over the past several years, there has been a considerable amount of research contributing to our knowledge regarding vaccination of patients with IBD.

Expert opinion: This updated review article focuses on the current immunization schedule for the IBD patient and stresses the important role of the gastroenterologist as an active participant in the health maintenance of their IBD patients.     

Oral Immunization with Lactobacillus casei Expressing the Porcine Circovirus Type 2 Cap and LTB Induces Mucosal and Systemic Antibody Responses in Mice

Porcine circovirus type 2 (PCV2) causes many diseases in weaned piglets, leading to serious economic losses to the pig industry. This study investigated the immune response following oral administration of Lactobacillus casei ATCC393 (L. casei 393) expressing PCV2 capsid protein (Cap) fusion with the Escherichia coli heat-labile toxin B subunit (LTB) in mice. Recombinant L. casei strains were constructed using plasmids pPG611.1 and pPG612.1. The expression and localization of proteins from recombinant pPG611.1-Cap-LTB (pPG-1-Cap-LTB)/L. casei 393 and pPG612.1-Cap-LTB (pPG-2-Cap-LTB)/L. casei 393 were detected. All recombinant strains were found to be immunogenic by oral administration in mice and developed mucosal and systemic immune responses against PCV2. The titers of specific antibodies in mice administered pPG-2-Cap-LTB/L. casei 393 were higher than those in mice administered pPG-1-Cap-LTB/L. casei 393 in serum and the mucosal samples. The mucosal immune response was not only limited to the gastrointestinal tract but was also generated in other mucosal parts. Thus, the application of recombinant L. casei could aid in vaccine development for PCV2.     

The development of 13-valent pneumococcal conjugate vaccine and its possible use in adults

Introduction: Worldwide, Streptococcus pneumoniae causes significant morbidity and mortality. The 23-valent pneumococcal polysaccharide vaccine (PPSV23) has been recommended for use in persons aged 65 years and over and in adults with certain chronic medical conditions. Pneumococcal conjugate vaccines (PCVs) have been developed for use in infants and children aged less than 5 years, and are being studied for use in adult populations.

Areas covered: The different types of pneumococcal vaccines are discussed. Studies comparing PPSV23 and PCVs, as well as the results of the widespread use of 7-valent PCV are covered. The possible extension of the use of 13-valent PCV to adults, particularly to vulnerable populations, is discussed. The MEDLINE database was used to identify relevant studies from literature published in English between January 1977 and January 2011. All studies of adults aged over 18 years were considered for the review.

Expert opinion: Elderly individuals and adults with chronic medical conditions who are at increased risk for pneumococcal disease would benefit from more effective prevention than is provided by the currently recommended PPSV23.     

Phylogenetic and genetic variation analyses of porcine circovirus type 2 isolated from China

Porcine circovirus type 2 (PCV 2) is a causative agent of PCV 2‐associated disease, which is a growing problem in the swine industry worldwide. High nucleotide substitution occurs in the capsid (Cap) gene of PCV 2, which allows the continuous evolution and the emergence of novel PCV 2 strains. In this study, we sequenced 24 Chinese PCV 2 strains collected from healthy and diseased pigs between 2013 and 2015. Analyses of the genome, Cap and phylogeny classified the 24 Chinese PCV 2 strains as PCV ‐2a (four of 24), PCV ‐2b (five of 24) and PCV ‐2d (15 of 24). All strains shared 89.5%–100% and 87.2%–100% identities with the nucleotide and amino acid (aa) sequences of Cap, respectively. Selection pressure analysis showed that five sites at the epitope regions in Cap were under positive selection. Further analysis by Jameson–Wolf antigenic index indicated that aa substitutions occurring at the epitope regions contributed to the antigenic alterations of the different PCV 2 strains. High genetic variation and genotype shift to PCV 2d occurred in recent years, and different genotypes coexisted in Chinese pig herds. The data provide evidence for the increased genetic diversity and insights into the molecular epidemiology of PCV 2.     

压力控制法肺复张在肺保护通气策略治疗ARDS中的应用

目的:研究应用压力控制通气方式的肺复张手法对ARDS患者肺复张效果的影响。方法:34例ARDS病人实施气管插管机械通气,采用压力控制小潮气量肺保护性通气策略,根据压力一容积曲线低位拐点(LIP)设置"最佳PEEP"为LIP+2cmH2O,维持吸入氧浓度≤0.60。都采用压力控制法肺复张技术。结果:治疗前后患者的一般情况(包括性别、平均年龄、HR、MAP、RR等)差异均无统计学意义。与PAC-RM前相比,RM后各时点PaO2、PaO2/FiO2均显著性升高(P0.05)。结论:压力控制通气方式的肺复张手法可显著增加ARDS患者的动脉氧分压(PaO2)和氧合指数(PaO2/FiO2)。     

Inactivated PCV2 one shot vaccine applied in 3-week-old piglets: improvement of production parameters and interaction with maternally derived immunity

The present study describes the effects of a commercially available vaccine against Porcine circovirus type 2 (PCV2) on clinical, pathological and virological outcomes of 3-week-old piglets from two farms with a clinical history of postweaning multisystemic wasting syndrome (PMWS). The study was a controlled, double-blinded, parallel group (1:1) and randomized trial (with a negative control) involving a total of 1239 animals. The study period comprised from weaning age (time of vaccination or PBS inoculation) until the first shipment of pigs to the slaughterhouse. The vaccine product was able to reduce clinical signs, PCV2 viral load in sera and faeces, and overall mortality in nurseries and fattening units. Moreover, average daily gain was significantly higher in vaccinated versus non-vaccinated piglets during the trial period. On the other hand, it was shown that maternally derived antibodies interfered with the development of an active humoral immune response after PCV2 vaccination.     

Pneumococcal vaccination for patients with COPD: current practice and future directions

Despite a level "A" recommendation by the Centers for Disease Control and Prevention, the use of pneumococcal polysaccharide vaccination in patients with COPD is supported by limited data. Clinical and laboratory studies have suggested that the currently approved vaccine is less effective in the population of COPD patients than in healthier patients, and to date no randomized-controlled trial of pneumococcal vaccination for COPD patients has demonstrated any beneficial effect. The implementation of a pneumococcal vaccine trial in the COPD population is problematic because of the large sample size required for studies examining clinical outcomes and the fact that no adequate in vitro assays have been available to serve as surrogate measures of vaccine protection. However, new laboratory methods have been developed and more accurate determination of the immunogenicity of pneumococcal vaccines is now possible. There is considerable interest in the development of an improved pneumococcal vaccine for patients with COPD, and advances in vaccine design hold considerable promise for improved prevention against pneumonia and acute exacerbations caused by Streptococcus pneumoniae. The following discussion will examine the available data supporting pneumococcal polysaccharide vaccine use, the currently available laboratory methods to measure immunogenicity, and advances in the development of an improved pneumococcal vaccine that could better protect patients with COPD against this pathogen.