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Objective:To screen and analyze the hub genes/gene panel for pediatric sepsis by bioinformatics methods.Methods:The pediatric sepsis chip datasets GSE66099 uploaded on Feb 19, 2015 and GSE145227 uploaded on Feb 13, 2020 were obtained from the gene expression omnibus (GEO) database and used to screen out the differentially expressed mRNA (DEmRNA) by the limma package. The Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were applied and performed for the functional and pathway enrichment analysis subsequently. The online database STRING and Cytoscape software were used to construct a protein interaction network (PPI) for DEmRNA and screen the hub gene. R package was used to analyze the expression and diagnostic significance of hub genes.Results:In this study, 160 total DEmRNA including 126 up-regulated mRNA and 34 down-regulated mRNA were obtained. By GO functional enrichment analysis, the results showed that DEmRNA were mainly enriched and focused on these areas: neutrophil activation, neutrophil degranulation, T cell activation and regulation of lymphocyte activation. KEGG enrichment pathway analysis showed that DEmRNA was mainly involved in signaling pathways including natural killer cell-mediated cytotoxicity and neutrophil extracellular trap formation. Ten DEGs (ARG1, RETN, MMP9, C3AR1, LCN2, FPR2, CCL5, CEACAM8, ELANE and DEFA4) as hub genes were screened by STRING and Cytoscape. A gene panel with 10 members had significant differences and the area under the ROC curve of each hub gene was greater than 0.7.Conclusion:By bioinformatics analysis, we find 10 genes that play an important role in the progression of pediatric sepsis, and provide a new theoretical basis for the diagnosis, prognostic markers and potential therapeutic targets of pediatric sepsis.
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Objective:To analyze the anti-drug resistance, molecular epidemiology and virulence gene distribution of non-A-F group serotype isolates of Salmonella enterica enteric subspecis, so as to provide epidemiological basis for clinical diagnosis and treatment.Methods:Serotyping, antimicrobial susceptibility test and whole genome sequencing were performed on 11 isolates of non-A-F group serotype isolates of Salmonella enterica enteric subspecies that were isolated from The Children′s Hospital, Zhejiang University School of Medicine between 2017 and 2020. The serotype, multilocus sequence typing and virulence gene of the whole genome sequencing results were analyzed. Results:In our hospital, the detection rate of non-A-F group serotype isolates of Salmonella enterica enteric subspecies was low (1.13%). Among the 11 strains, there were 3 strains belong to Jangwani serotype, 2 strains of Hvittingfoss serotype, and Wandsworth, Pomona, Kedougou, Urbana, Poona and Kumasi serotypes have 1 strain each. Except for the two multi-drug resistant strains, the other strains were sensitive to most antibiotics, and the MICs were at low levels. A total of 9 ST types were detected in the 11 strains, the 3 Jangwani serotype strains were ST3918, and the other isolates were of different ST types. The phylogenetic tree shown that the three strains of Jangwani serotype were closely related. A total of 103 virulence genes were detected in the 11 strains, including 78 genes related to secretion system, 21 genes related to adherence, 2 genes related to magnesium uptake, 1 gene related to resistance to antimicrobial peptides and 1 gene related to typhoid toxin. Conclusions:The detection rate of the non-A-F group serotype isolates of Salmonella enterica enteric subspecies was low, and the sensitivity of the isolates to common antibiotics was high. The ST types and genetic relationship showed diversity. Clinical laboratory should pay attention to the detection of the non-A-F group serotype isolates of Salmonella enterica enteric subspecies, and the changes in drug resistance and virulence genes of the isolates should be closely monitored.
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Objective:To investigate the role of type Ⅵ secretion system (T6SS) in the pathogenicity and antibiotic resistance of Acinetobacter baumanii. Methods:From January 1 to December 31, 2016, a total of 45 Acinetobacter baumanii isolates were collected from patients with bloodstream infection in the First Affiliated Hospital of Wenzhou Medical University. The susceptibilities to commonly used antimicrobial agents were determined by VITEK 2 Compact automatic microbiology analyzer. Detection of T6SS characteristic gene hemolysin coregulated protein ( hcp) was achieved by polymerase chain reaction. Biofilm formations, serum resistances and competition tests of T6SS-positive/negative Acinetobacter baumanii were performed in vitro. The clinical data of patients with bloodstream infection were collected and analyzed. Chi-square test, t test and Kruskal-Wallis test were conducted for statistical analysis. Results:The positive rate of T6SS in 45 Acinetobacter baumanii isolates was 53.3% (24/45). The resistance rates of T6SS-positive Acinetobacter baumanii to ceftazidime, ciprofloxdcin, gentamicin, imipenem, levofloxacin, piperacillin/tazobactam, tobramycin and cefepime (95.8%, 95.8%, 66.7%, 95.8%, 79.2%, 95.8%, 79.2%, 91.7%)were all higher than that of T6SS-negative Acinetobacter baumanii (28.6%, 28.6%, 28.6%, 28.6%, 9.5%, 23.8%, 23.8%, 28.6%), and the differences were all statistically significant ( χ2=22.12, 22.12, 6.51, 22.12, 21.83, 24.72, 13.79, 18.97, respectively, all P<0.05). The biofilm formation ability, serum resistance and competitive ability of T6SS-positive Acinetobacter baumanii were stronger than those of T6SS-negative Acinetobacter baumanii, and the differences were all statistically significant ( t=4.99, Z=-2.61 and -2.27, respectively, all P<0.05). The positive rate of T6SS isolated from intensive care unit (ICU) ward (80.0%, 16/20) was significantly higher than that from non-ICU ward (32.0%, 8/25; χ2=10.29, P<0.05). But T6SS had no effect on the prognosis of patients ( χ2=1.74, P=0.188). Conclusions:T6SS of Acinetobacter baumanii is associated with high pathogenicity, and the high drug resistance rate makes treatment extremely difficult. Physicians need to pay much attention, especially to the patients from ICU wards.
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Objective To investigate the chlorhexidine acetate-resistance in Klebsiella pneumoniae ( K. pneumoniae) clinical isolates and to analyze the possible mechanisms and molecular epidemiology of re-sistant isolates. Methods A total of 332 K. pneumoniae clinical isolates were collected in the First Affilia-ted Hospital of Wenzhou Medical University in 2015. Standard agar dilution was used to screen chlorhexidine acetate-resistant isolates. The minimum inhibition concentrations ( MIC) of chlorhexidine acetate to resistant isolates with and without the presence of carbonyl cyanide m-chlorophenyl hydrazone ( CCCP) , which was an efflux pump inhibitor, were analyzed. Efflux pump genes of cepA, qacE and qacΔE1 that carried by and ex-pressed in those isolates were detected by polymerase chain reaction ( PCR) and quantitative real-time PCR ( RT-qPCR) , respectively. The biofilm formation ability was measured by crystal violet staining. The homol-ogy among the chlorhexidine acetate-resistant isolates was investigated with multilocus sequence typing ( MLST) and pulsed-field gel electrophoresis ( PFGE) . Results Twenty-five K. pneumoniae strains were re-sistant to chlorhexidine acetate. The MIC values of chlorhexidine acetate for them were reduced by at least four-fold in the presence of CCCP. Strains carrying the genes of cepA, qacE and qacΔE1 accounted for 100％, 40％ and 40％, respectively. The expression of the efflux pump genes in the chlorhexidine acetate-resistant isolates was higher than that in the susceptible isolates. The biofilm formation ability of the chlo-rhexidine acetate-resistant isolates was better than that of the susceptible isolates. Furthermore, negative, weak-positive and positive biofilm formation ability was observed in four ( 16％) , 20 ( 80％) and one (4％) strains, respectively. The results of MLST and PFGE showed that the 25 chlorhexidine acetate-resist-ant isolates belonged to 19 different sequence types ( ST) with diverse PFGE patterns. Conclusions This study suggested that active efflux was the main mechanism of chlorhexidine acetate resistance in K. pneumoni-ae. The 25 chlorhexidine acetate-resistant K. pneumoniae strains possessed different biofilm formation ability and shared low homology.
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Objective@#To investigate the in vitro antibacterial activity of triclosan combined with different antibacterial agents against triclosan-resistant multidrug-resistant Acinetobacter baumannii (A.baumannii).@*Methods@#A total of 626 A. baumannii strains were collected from the First Affiliated Hospital of Wenzhou Medical University from 2016 to 2017. The sensitivity of these A. baumannii strains to common antibiotics was detected by VITEK 2-compact automatical microbiological analyzer and the minimum inhibitory concentrations (MIC) of triclosan were detected by agar dilution method. Checkerboard method was used to detect the changes in MIC values of triclosan against 16 triclosan-resistant multidrug-resistant A. baumannii strains after it was used in combination with four external ointments, including gentamicin, erythromycin, chloramphenicol and kanamycin, and three common antibiotics of imipenem, meropenem and ciprofloxacin, respectively. Fractional inhibitory concentration index (FICI) was used to evaluate the joint bacteriostatic effects.@*Results@#Among the 626 A. baumannii strains, 17 were resistant to triclosan with a drug resistance rate of 2.7% (17/626). These triclosan-resistant strains had high MIC values for ciprofloxacin, imipenem, ceftazidime and other commonly used clinical antibiotic and most of them were multidrug-resistant. After triclosan was used in combination with seven different antibacterial drugs, the MIC values of all drugs decreased to various degrees compared with those when they were used alone. Triclosan in combination with gentamicin, chloramphenicol and ciprofloxacin showed synergistic effects on 62.5%, 56.25% and 62.5% of the 16 strains and additive effects on 37.5%, 43.75% and 37.5%, respectively. When it was used in combination with erythromycin, kanamycin, imipenem and meropenem, synergistic effects on 37.5%, 25%, 12.5% and 12.5%, additive effects on 37.5%, 56.25%, 62.5% and 62.5%, and indifferent effects on 25%, 18.75%, 25% and 25% of the strains were detected, respectively. No antagonistic effect was found between triclosan and any of the above antibiotics.@*Conclusions@#Triclosan combined with gentamicin, chloramphenicol and ciprofloxacin had better in vitro antibacterial effects against the triclosan-resistant multidrug-resistant A. baumannii strains in this study with synergistic and additive effects. Some indifferent effects were found between triclosan and kanamycin, erythromycin, imipenem and meropenem, but no antagonistic effects were detected.
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Objective To investigate the in vitro antibacterial activity of triclosan combined with different antibacterial agents against triclosan-resistant multidrug-resistant Acinetobacter baumannii ( A. bau-mannii) . Methods A total of 626 A. baumannii strains were collected from the First Affiliated Hospital of Wenzhou Medical University from 2016 to 2017. The sensitivity of these A. baumannii strains to common an-tibiotics was detected by VITEK 2-compact automatical microbiological analyzer and the minimum inhibitory concentrations ( MIC) of triclosan were detected by agar dilution method. Checkerboard method was used to detect the changes in MIC values of triclosan against 16 triclosan-resistant multidrug-resistant A. baumannii strains after it was used in combination with four external ointments, including gentamicin, erythromycin, chloramphenicol and kanamycin, and three common antibiotics of imipenem, meropenem and ciprofloxacin, respectively. Fractional inhibitory concentration index ( FICI) was used to evaluate the joint bacteriostatic effects. Results Among the 626 A. baumannii strains, 17 were resistant to triclosan with a drug resistance rate of 2. 7％ (17/626). These triclosan-resistant strains had high MIC values for ciprofloxacin, imipenem,ceftazidime and other commonly used clinical antibiotic and most of them were multidrug-resistant. After tri-closan was used in combination with seven different antibacterial drugs, the MIC values of all drugs de-creased to various degrees compared with those when they were used alone. Triclosan in combination with gentamicin, chloramphenicol and ciprofloxacin showed synergistic effects on 62. 5％, 56. 25％ and 62. 5％of the 16 strains and additive effects on 37. 5％, 43. 75％ and 37. 5％, respectively. When it was used in combination with erythromycin, kanamycin, imipenem and meropenem, synergistic effects on 37. 5％, 25％, 12. 5％ and 12. 5％, additive effects on 37. 5％, 56. 25％, 62. 5％ and 62. 5％, and indifferent effects on 25％, 18. 75％, 25％ and 25％ of the strains were detected, respectively. No antagonistic effect was found between triclosan and any of the above antibiotics. Conclusions Triclosan combined with genta-micin, chloramphenicol and ciprofloxacin had better in vitro antibacterial effects against the triclosan-resist-ant multidrug-resistant A. baumannii strains in this study with synergistic and additive effects. Some indiffer-ent effects were found between triclosan and kanamycin, erythromycin, imipenem and meropenem, but no antagonistic effects were detected.
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Objective@#To investigate the distribution and expression of T3SS virulence genes in clinically isolated Pseudomonas aeruginosa (P. aeruginosa) strains and its correlation with drug resistance. @*Methods@#A total of 68 P. aeruginosa isolates were collected from the First Affiliated Hospital of Wenzhou Medical University in 2015. The antimicrobial susceptibility was detected by the agar dilution method. The distribution of virulence genes such as exoU, exoS, exoT and exoY from different isolates was detected by PCR. The expression levels of transcriptional regulator genes (ptrA and exsA) and effector-related genes (exoT and exoS) in some isolates were determined by real-time fluorescence quantitative PCR, and the Pearson correlation analysis was used to analyze the results. @*Results@#The detection rates of exoT and exoY in 68 P. aeruginosa isolates were higher, accounting for 79.4% and 75.0%, respectively. The detection rate of exoT in wound-sourced isolates was significantly higher than that in sputum (97.0% vs 61.8%, P＜0.01). In addition, the genotype of exoU - /exoS + was the most common, accounting for 51.5% (35/68). The resistance rates of sputum-sourced isolates to imipenem and meropenem were significantly higher than that of wound-sourced isolates (47.1% vs 8.8%, 47.1% vs 14.7%, P＜0.01). The resistance rates of isolates carrying exoU gene to carbapenems, aminoglycosides and fluoroquinolones were higher than those of isolates carrying exoS, exoT or exoY genes. Pearson correlation analysis showed that the expression level of ptrA gene was negatively correlated with those of exoT, exoS and exsA genes (P＜0.05). @*Conclusion@#The P. aeruginosa isolates from our hospital carrying T3SS virulence genes exoT and exoY are common, and the virulence genes are related to the drug resistance of P. aeruginosa. In addition, ptrA may be a potential negative regulatory gene for the expression of T3SS virulence genes.