Factors behind the prevalence of carbapenem-resistant Klebsiella pneumoniae in pediatric wards.

ABSTRACT: The emergence of carbapenem-resistant Enterobacteriaceae made the treatment difficult, which has become a significant issue of public health. A sharp increase of carbapenem-resistance rate in Klebsiella pneumoniae was observed in a maternity and child health care hospital in Zunyi, China, in 2014.In 2015 to 2016, carbapenem-resistant Klebsiella pneumoniae (CRKp) isolated from all the clinical samples were analyzed to identify the carbapenem-resistance genes. They were then fingerprinted in order to determine their genetic relationship. Clinical data such as usage of imipenem in 2012 to 2016 and the nosocomial infection surveillance data were analyzed.Thirty-five isolates of CRKp out of 4328 various pathogens were obtained, and blaNDM-1 was identified to be the most common resistant gene present in the CRKp isolates. The fingerprint analysis identified 15 major clusters of CRKp isolates. The bacteria with close proximity relationship tended to be from the same wards. However, a few CRKp isolates from different wards were found to be genetically highly related. The clinical data showed a significantly higher usage of carbapenems in 2012 to 2013 before the CRKp rate sharply increased in 2014. The nosocomial infection surveillance showed an unexpectedly high rate of failures to meet the requirement of the hospital environment hygiene and hand hygiene in the neonatal ward.The increasing isolation rate of CRKp was associated with poorly regulated usage of carbapenems, impropriate medical practices, and the poor hospital environmental hygiene and hand hygiene.

Effect of long non­coding RNA AK021443 on promoting hepatic fibrosis in vitro.

Long non­coding (lnc)RNAs serves an important role in the occurrence and development of hepatic fibrosis. lncRNA AK021443 is highly expressed in hepatocellular carcinoma (HCC) and promotes HCC cell proliferation, invasion and migration. The present study aimed to investigate the effect of AK021443 on hepatic fibrosis. AK021443 was overexpressed in the human LX­2 hepatic stellate cell (HSC) line using a plasmid to observe its effect on hepatic fibrosis in vitro. A Cell Counting Kit­8 assay was performed to assess cell proliferation, whereas cell cycle distribution and related proteins were analyzed via flow cytometry and western blotting, respectively. The protein expression levels of epithelial­mesenchymal transition (EMT)­associated and extracellular matrix (ECM) proteins were also analyzed via western blotting. Immunofluorescence was conducted to observe the generation of collagen1, and the activity of inflammatory factors and reactive oxygen species (ROS) was also analyzed. Compared with the pcDNA group, AK021443 overexpression significantly promoted cell proliferation, enhanced the transition of cells from G1 to S phase and increased the expression of cyclin­dependent kinase 2 and cyclin D1, but reduced the p21 protein expression levels. In addition, EMT capabilities, ECM deposition and the generation of collagen1 were increased by AK021443 overexpression compared with the pcDNA group. Moreover, AK021443 overexpression significantly increased the release of inflammatory cytokines, including TGF­ß, interleukin­1ß, platelet derived growth factor, epidermal growth factor and ROS, compared with the pcDNA group. In conclusion, the present study suggested that AK021443 overexpression increased HSC proliferation, activation and the proinflammatory response, indicating the potential role of AK02144 in aggravating hepatic fibrosis.

Neisseria gonorrhoeae NGO2105 Is an Autotransporter Protein Involved in Adhesion to Human Cervical Epithelial Cells and in vivo Colonization.

Autotransporters are important virulence factors in the outer membrane of gram-negative bacteria. Although several autotransporters have been identified in Neisseria meningitidis, only IgA1 protease has been identified in Neisseria gonorrhoeae. A sequence analysis showed a marked difference in the distribution of autotransporters between the two strains. It has been speculated that only two autotransporters, the IgA1 protease and the NGO2105 protein, might be encoded by N. gonorrhoeae. Here, we describe the identification of NGO2105, a new autotransporter in N. gonorrhoeae. A sequence alignment showed that NGO2105 is highly similar to the adhesion and penetration protein (App) in N. meningitidis. We found that NGO2105 is exported to the outer membrane, cleaved and released into the culture supernatant by endogenous serine protease activity in N. gonorrhoeae and E. coli. The site-directed mutagenesis of S267A in the predicted enzyme catalytic triad abolished autoproteolytic cleavage to allow secretion. The NGO2105 ß-barrel shows the ability to translocate the heterologous Hbp passenger domain. NGO2105 is involved in gonococcal adherence to and invasion into human cervical epithelial cells. Furthermore, antibodies raised against NGO2105 are able to block gonococcal adherence to human cervical epithelial cells. The Δngo2105 mutant and anti-NGO2105 antiserum significantly attenuated the colonization of N. gonorrhoeae in mice. Collectively, our results suggest that the newly identified serine protease autotransporter NGO2105 represents a novel virulence factor of gonococcus and a potential vaccine target.

Protection against fatal pneumonia through mucosal and subcutaneous immunization with the pneumococcal SP0148 protein.

Streptococcus pneumoniae infection is associated with very high morbidity and mortality throughout the world. Vaccines are an effective measure for the reduction of S. pneumoniae infection. In particular, protein vaccines are attracting increasing attention because of their good immunogenicity and wide coverage of serotypes. Therefore, identifying effective protein vaccine targets is important for protein vaccine development. SP0148 is a promising protein vaccine target for S. pneumoniae and is capable of reducing S. pneumoniae colonization in the nasopharynx of mice through the IL-17A pathway. However, the protective effects of SP0148 in fatal pneumococcal infection have not been evaluated. This study used subcutaneous and nasal immunization routes to systematically evaluate the protective effects of the SP0148 protein in fatal pneumococcal infection. Subcutaneous and nasal mucosal immunization with recombinant SP0148 protein produced effective immune protection against infection with a lethal dose of S. pneumoniae and significantly prolonged survival time and increased the survival rate of mice. Furthermore, nasal immunization with SP0148 induced mouse splenocytes to secrete high levels of the cytokines IFN-γ and IL-17A. Both recombinant SP0148 protein and its antiserum inhibited the adhesion of S.pneumoniae D39 to A549 human lung epithelial cells in a dose-dependent manner. In summary, SP0148 induced mice to produce protective immune responses to fatal S. pneumoniae infection, and our results could contribute to the accumulating data on the use of SP0148 protein vaccines.