Yingli Li

Risk factors for ventilator-associated pneumonia in the neonatal intensive care unit: a meta-analysis of observational studies

Ventilator-associated pneumonia (VAP) is a common and serious problem among mechanically ventilated patients in intensive care units (ICU), especially for the newborn. However, limited literatures have been reviewed to synthesize the finding of previous papers to investigate the risk factors for VAP although it has been a serious complication of mechanical ventilation (MV) with a high morbidity and mortality in the newborn. We performed this meta-analysis to extend previous knowledge for developing VAP prevention strategies by identifying the potential risk factors related to VAP in the neonatal intensive care unit (NICU). The relevant literatures published up to July 2013 were searched in the databases of PubMed, Cochrane Central Register of Controlled Trials, Embase, and Web of Science. Three reviewers screened those literatures and extracted data according to the inclusion and exclusion criteria independently. A total of eight studies including 370 cases and 1,071 controls were identified. Ten risk factors were found to be related to neonatal VAP which were listed as follows in order by odds ratios (ORs): length of stay in NICU (OR 23.45), reintubation (OR 9.18), enteral feeding (OR 5.59), mechanical ventilation (OR 4.04), transfusion (OR 3.32), low birth weight (OR 3.16), premature infants (OR 2.66), parenteral nutrition (OR 2.30), bronchopulmonary dysplasia (OR 2.21), and tracheal intubation (OR 1.12). Conclusion: We identified ten variables as independent risk factors for the development of VAP: length of stay in NICU, reintubation, enteral feeding, mechanical ventilation, transfusion, low birth weight, premature infants, parenteral nutrition, bronchopulmonary dysplasia, and tracheal intubation. Due to several limitations in the present study, further large and well-designed studies are needed to confirm the conclusion.

Interferon-Inducible Transmembrane Protein 3 Genetic Variant rs12252 and Influenza Susceptibility and Severity: A Meta-Analysis

Background The pandemic influenza A (H1N1) pdm09 virus, avian influenza A (H5N1) virus, and influenza A (H7N9) virus induced severe morbidity and mortality throughout the world. Previous studies suggested a close association between the interferon-induced transmembrane protein-3 (IFITM3) genetic variant rs12252 and influenza. Here, we explored the correlation between the rs12252 and influenza susceptibility and severity using meta-analysis. Methods Relevant studies published before May 22, 2014 were retrieved from PubMed, ISI web of knowledge, EBSCO, and Cochrane central register of controlled trials databases. Association between rs12252 and influenza susceptibility and severity were determined using statistical analysis of odds ratios (ORs). Results A total of four studies consisting of 445 cases and 4180 controls were included in our analysis. Generally, there is increased risk of influenza in subjects carrying rs12252 in the recessive model (CC vs. CT+TT: OR = 2.35, 95% CI: 1.49-3.70, P<0.001), the dominant model (CC+CT vs. TT: OR=1.60, 95% CI: 1.18–2.22, P=0.003), the homozygote comparison (CC vs. TT: OR=4.11, 95% CI: 2.15–7.84, P<0.001), and the allele contrast (C vs. T: OR=1.67, 95% CI: 1.32–2.13, P<0.001). Stratification analysis of ethnicity and severity revealed a significant increase in influenza susceptibility by IFITM3-SNP rs12252 among both Asian and Caucasian population. SNP rs12252 shows significant impact on severe infections (P<0.05), but not on mild influenza. Besides, our result also associated rs12252 with influenza severity (severe vs. mild: OR=2.37, 95% CI: 1.32–4.25, P=0.004), (severe vs. control: OR=2.70, 95% CI: 1.85–3.94, P<0.001). Conclusion Our meta-analysis suggests a significant association between a minor IFITM3 allele (SNP rs12252-C) with severe influenza susceptibility, but not in mild influenza subjects, in both UK Caucasians and Han Chinese population. The rs12252-C allele causes a 23.7% higher chance of infection and also constitutes a risk factor for more severe influenza.

Bronchopulmonary Infection of Lophomonas blattarum : A Case and Literature Review

Human infections with Lophomonas blattarum are rare. However, the majority of the infections occurred in China, 94.4% (136 cases) of all cases in the world. This infection is difficult to differentiate from other pulmonary infections with similar symptoms. Here we reported a case of L. blattarum infection confirmed by bronchoalveolar lavage fluid smear on the microscopic observations. The patient was a 21-year-old female college student. The previous case which occurred in Chongqing was 20 years ago. We briefly reviewed on this infection reported in the world during the recent 20 years. The epidemiological characteristics, possible diagnostic basis, and treatment of this disease is discussed in order to provide a better understanding of recognition, diagnosis, and treatment of L. blattarum infection.

Influence of cAMP receptor protein (CRP) on bacterial virulence and transcriptional regulation of allS by CRP in Klebsiella pneumoniae

cAMP receptor protein (CRP) is one of the most important transcriptional regulators, which can regulate large quantities of operons in different bacteria. The gene allS was well-known as allantoin-utilizing capability and involving in bacterial virulence in Klebsiella pneumoniae (K. pneumoniae). The specific DNA recognition motif of transcription regulator CRP was found in allS promoter region. Therefore, this study is aimed to investigate the function of CRP on virulence and its transcriptional regulation mechanism to gene allS in K. pneumoniae. The wild-type (WT) K. pneumoniae NTUH-2044, crp knockout (Kp-Δcrp) and the complemented knockout (KpC-Δcrp) strains were used to determine the function of crp gene. The lacZ fusion, qRT-PCR, electrophoretic mobility shift and DNase I footprinting assays were performed to study the transcriptional regulation of CRP on allS. The result showed a decreased virulence in crp knockout strain. Complement through supplementing crp fragment in expression plasmid partially restore virulence of knockout bacteria. The CRP could bind to the allS promoter-proximal region and the binding site was further refined to be located from 60bp to 94bp upstream of the allS promoter. Based on these results, we proposed that CRP is an essential virulence regulator and knock out of crp gene will result in reduced virulence in K. pneumoniae. In the meantime, the transcription of gene allS is positively regulated by CRP via directly binding to upstream of allS promoter.

Risk factors for infection and/or colonisation with extended-spectrum β-lactamase-producing bacteria in the neonatal intensive care unit: a meta-analysis

Extended-spectrum β-lactamase (ESBL)-producing bacteria are an important cause of healthcare-associated infections in the neonatal intensive care unit (NICU). The aim of this meta-analysis was to identify risk factors associated with infection and/or colonisation with ESBL-producing bacteria in the NICU. Electronic databases were searched for relevant studies published from 1 January 2000 to 1 July 2016. The literature was screened and data were extracted according to the inclusion and exclusion criteria. The Z-test was used to calculate the pooled odds ratio (OR) of the risk factors. ORs and their 95% confidence intervals were used to determine the significance of the risk. A total of 14 studies, including 746 cases and 1257 controls, were identified. Thirteen risk factors were determined to be related to infection and/or colonisation with ESBL-producing bacteria in the NICU: birthweight [standardised mean difference (SMD) = 1.17]; gestational age (SMD = 1.36); Caesarean delivery (OR = 1.76); parenteral nutrition (OR = 7.51); length of stay in the NICU (SMD = 0.72); mechanical ventilation (OR = 4.8); central venous catheter use (OR = 2.85); continuous positive airway pressure (OR = 5.0); endotracheal intubation (OR = 2.82); malformations (OR = 2.89); previous antibiotic use (OR = 6.72); ampicillin/gentamicin (OR = 2.31); and cephalosporins (OR = 6.0). This study identified risk factors for infection and/or colonisation with ESBL-producing bacteria in the NICU, which may provide a theoretical basis for preventive measures and targeted interventions.

Risk factors of lower respiratory tract infection in patients after tracheal intubation under general anesthesia in the Chinese health care system: A meta-analysis.

BACKGROUND Lower respiratory tract infection (LRTI) after tracheal intubation under general anesthesia poses a serious threat to worldwide health care systems, especially those in developing countries. However, a significant number of studies have found inconsistent results in their investigation of the corresponding risk factors. METHODS Relevant articles published up to September 2015 were retrieved from PubMed, Ovid, Embase, China National Knowledge Infrastructure, Chinese Biological Medical Database, China Science and Technology Journal Database, and Wanfang Data. The z test was used to determine the significance of the pooled odds ratio (OR). ORs and 95% confidence intervals were used to compare the risk factors of LRTI after intubation under general anesthesia. RESULTS Fifteen case-control studies that included 27,304 participants were identified. We identified the following variables as independent risk factors: duration of general anesthesia >3 hours (OR, 2.45), age >60 years (OR, 2.35), normal endotracheal tube (OR, 1.63), deep intubation (OR, 2.66), unpracticed intubation (OR, 2.61), postoperative extubation time >2 hours (OR, 3.76), smoking history (OR, 3.02), chronic respiratory disease history (OR, 2.30), incomplete extubation indication (OR, 3.54), thoracic or craniocerebral surgery (OR, 1.90), and emergent surgery (OR, 2.54). CONCLUSIONS Eleven risk factors, including surgery, anesthesia, and health condition, were related to LRTI after intubation under general anesthesia. Given the limitations of this study, well-designed epidemiologic studies with a large sample size should be performed in the future.

Serum Leptin Levels in Patients with Hepatitis B: A Meta-analysis

Background and Aims: Hepatitis B virus (HBV) infection is a widespread disease affecting people worldwide. With more and more research on the deepening of the leptin, which suggested a close relationship between serum leptin levels and HBV. In this study, we explored the correlation between serum leptin levels and HBV through meta-analysis. Methods: Potentially relevant studies between 2007 and 2017 were retrieved from PubMed, Ovid, Embase, Web of Science, Weipu Journal, Chinese Biomedical, China National Knowledge Infrastructure, and Wan Fang Data. Z-test was used to determine the significance of the pooled standardized mean difference (SMD). Results: We analyzed 16 studies, which involved 884 HBV patients and 618 healthy controls. And then pooled the SMD and calculated the 95% confidence interval (CI) by using a random-effects model from heterogeneity analysis. High serum leptin levels were observed in HBV patients (SMD: 1.16, 95%CI: 0.72-1.59, P<0.00001). Stratification analysis on the ethnicity, study design, and detection method revealed significant increases in the serum leptin levels among the Asian population of the ethnicity subgroup, case-control study of the study design subgroup, and ELISA or RIA of the detection method subgroup. Conclusion: This meta-analysis suggests a significant difference between HBV patients and healthy controls. Therefore, serum leptin levels may serve as a prognostic marker for hepatitis B disease.

Transcriptional regulation of galF by RcsAB affects capsular polysaccharide formation in Klebsiella pneumoniae NTUH-K2044

RcsAB is an atypical two-component regulatory system that can regulate exopolysaccharide biosynthesis and is involved in the virulence of K. pneumoniae. The gene galF is well known as a gene involved in the biosynthesis of capsular polysaccharide (CPS). The specific DNA identification sequence for transcriptional regulation of RcsAB was found to be present in the promoter region of galF. This study aimed to detect the function of RcsAB in virulence and in biofilm and CPS formation. In addition, the transcriptional regulation of the galF gene in K. pneumoniae was studied. To determine the function of rcsAB gene, the wild-type K. pneumoniae strain NTUH-K2044 and the rcsAB knockout and complemented strains were used. The results showed decreased virulence, biofilm formation, and CPS levels in the rcsAB knockout strain. Complementation of the knockout by introducing an rcsAB fragment on an expression plasmid partially restored the virulence, biofilm, and CPS functions of the knockout strain. It indicated that the rcsAB genes might affect CPS formation and virulence of K. pneumonia. RT-qPCR, EMSA and DNase I footprinting assays were conducted to identify the transcriptional regulation of galF by RcsAB. RcsAB was seen to bind to the galF promoter-proximal region, and the binding site was further identified to be located from -177 bp to -152 bp upstream of the galF promoter. In conclusion, RcsAB could regulate the transcription of the galF gene positively by binding to the galF promoter DNA directly, and then affects the CPS formation of K. pneumonia.

Genome-wide identification of genes regulated by RcsA, RcsB, and RcsAB phosphorelay regulators in Klebsiella pneumoniae NTUH-K2044

Rcs phosphorelay system is a two-component signal transduction system, which can regulate the transcription of capsule polysaccharide and biofilm related genes in Enterobacteriaceae. In this study, microarray technology was used to investigate the overall genes regulated by RcsA, RcsB, and RcsAB and the regulation mechanism in Klebsiella pneumoniae, then COG analysis was performed to explore the functions of the differentially expressed genes. According to the microarray data result, a total of 45, 223 and 217 genes regulated by RcsA, RcsB, and RcsAB were screened. The result of COG analysis suggested that inorganic ion transport and metabolism related genes have a majority in RcsA regulating genes. Most of RcsB regulated genes were showed involved in energy production and conversion process. Besides Carbohydrate transport and metabolism genes were identified as the major components of the RcsAB regulated genes. 15 differentially expressed genes were confirmed by quantitative real-time PCR (RT-qPCR). The RT-qPCR results indicated that 13 genes consistent with microarray data. The results of this study provided important evidence for further research to investigate the influence of RcsA, RcsB, RcsAB regulators and further efforts to address the diseased caused by K.pneumoniae, such as pneumonia, bacteremia, and urinary tract infection.

Risk factors of bloodstream infections in recipients after liver transplantation: a meta-analysis

PurposeBloodstream infection (BSI) is an important cause of adverse outcomes for recipients with liver transplantation (LT). This meta-analysis aimed to identify risk factors associated with post-LT BSI.MethodsRelevant studies published up to June 2017 were searched from seven electronic databases. The studies were reviewed according to the inclusion and exclusion criteria. The Z test was used to determine the pooled odds ratio (OR) or standardized mean difference (SMD) of the risk factors. ORs and their corresponding 95% confidence intervals (CIs), or SMDs and their corresponding 95% CIs were used to identify the significant difference of risk factors.ResultsSeventeen studies enrolling 4410 recipients were included. Eleven risk factors were identified to be associated with BSI after LT: male recipient (OR = 1.28), ascites (OR = 1.68), model for end-stage liver disease (MELD) score (SMD = 0.20), Child–Pugh class C (OR = 1.69), operation time (SMD = 0.18), incompatible blood type (OR = 2.87), operative blood loss (SMD = 0.33), rejection (OR = 1.72), biliary complications (OR = 1.91), hemodialysis (OR = 3.37), and retransplantation (OR = 2.86).ConclusionsAlthough some risk factors were identified as significant factors for BSI after LT, which may provide a basis for clinical prevention, well-designed prospective studies should be done to overcome the limitations of this study.