ObjectiveTo investigate the condensate pollution in the pipeline of severe pneumonia patients undergoing mechanical ventilation.MethodsFrom January 2017 to January 2019, 120 patients with severe pneumonia treated by mechanical ventilation in our hospital were collected continuously. The lower respiratory tract secretions were collected for bacteriological examination. At the same time, the condensed water in the ventilator exhaust pipe was collected for bacteriological examination at 4, 8, 12, 16, 20 and 24 hours after tracheal intubation and mechanical ventilation. The bacterial contamination in the condensed water at different time points was analyzed and separated from the lower respiratory tract. The consistency of bacteria in secretion and drug resistance analysis of bacterial contamination in condensate water were carried out.ResultsOf the 120 patients with severe pneumonia after mechanical ventilation, isolates were cultured in the lower respiratory tract secretions of 102 patients. One strain was cultured in 88 cases, two strains were cultured in 10 cases, and three strains were cultured in 4 cases. The isolates were mainly Gram-negative bacteria (57.5%) and Gram-positive bacteria (42.5%). The most common isolates were Pseudomonas aeruginosa, Staphylococcus aureus and Acinetobacter baumannii. The contamination rate of condensate water was 5.0% at 4 hours, 37.5% at 8 hours, 60.0% at 12 hours, 76.7% at 16 hours, 95.0% at 20 hours, and 100.0% at 24 hours, respectively. The bacterial contamination rate in condensate water at different time points was statistically significant (P=0.000). The pollution rate at 4 hours was significantly lower than that at 8 hours (P=0.000). Gram-negative bacteria accounted for 57.5% and Gram-positive bacteria accounted for 42.5%. The most common isolates were Staphylococcus aureus, Pseudomonas aeruginosa and Acinetobacter baumannii. The consistency of bacteria in lower respiratory tract and condensate water was 83.3% in severe pneumonia patients undergoing mechanical ventilation. The overall resistance of Pseudomonas aeruginosa, Acinetobacter baumannii and Staphylococcus aureus was higher, but the resistance to imipenem/cilastatin was lower.ConclusionsThe bacterial contamination in the condensate of patients with severe pneumonia during mechanical ventilation is serious. The pollution rate is low within 4 hours. It is consistent with the bacterial contamination in lower respiratory tract and the bacterial resistance is high.
目的：为临床合理应用抗生素提供依据。方法：采用VITEK 32及GNS--120药敏卡、GPS -107药敏卡进行细菌的鉴定及药敏实验。结果：320 株病原菌中，革兰氏阳性菌占28.75 %，革兰氏阴性菌占71.25 %，其中大肠埃希菌、铜绿假单胞菌、鲍曼复合醋酸钙不动杆菌、阴沟肠杆菌、金黄色葡萄球菌是临床上主要致病菌。结论：临床应科学合理选用抗生素，尽量减少和延缓耐药菌的发生及发展。
Peptidoglycan is an important component of bacterial cell wall, which plays an important role in maintaining the integrity of bacterial cell structure, stimulating immune response, and anti-infection. Peptidoglycan recycling is an indispensable process for bacterial cell growth and reproduction. In recent years, it has been reported that the peptidoglycan recycling is closely related to the occurrence and development of bacterial resistance, especially with the antibacterial activity of β-lactam antibiotics. In this paper, the relationship between peptidoglycan recycling and resistance is described by combining relevant reports and taking Mycobacterium tuberculosis and Pseudomonas aeruginosa as examples, so as to promote the understanding of bacterial resistance mechanisms and provide potential targets for the development of new antimicrobial drugs.
ObjectiveTo study the distributions of virulence genes of Klebsiella pneumoniae (KP) and the distribution of hypervirulent KP (HvKP), and assess the performance of a single gene to predict HvKP.MethodsPolymerase chain reaction (PCR) method was used to analyze 12 virulence-related genes (entB, irp2, iroN, iucA, mrkD, fimH, c-rmpA, p-rmpA2, p-rmpA, wzy-K1, allS and peg-344) and drug-resistance gene blaKPC among 376 clinical KP strains collected from January 2016 to December 2018. Sequence types (ST) of KP were determined after sequencing and comparison, following the detection of 7 house-keeping genes (gapA, infB, mdh, pgi, phoE, rpoB and tonB) by PCR method. Statistical analyses were made for the distributions of virulence genes of KP and the distribution of HvKP with GraphPad Prism 8 software.ResultsAmong the 376 KP strains, the positive rates of entB, irp2, iroN, iucA, mrkD, fimH, c-rmpA, p-rmpA2, p-rmpA, wzy-K1, allS and peg-344 were 100.0%, 76.9%, 22.1%, 28.2%, 97.6%, 97.1%, 1.6%, 24.5%, 21.0%, 7.4%, 4.8% and 31.6%, respectively. The positive rates of the aforementioned virulence genes in the blaKPC-positive group (n=167) were 100.0%, 94.0%, 7.2%, 16.8%, 97.0%, 96.4%, 0.0%, 15.0%, 6.6%, 0.0%, 0.0% and 21.0%, respectively, and those in the blaKPC-negative group (n=209) were 100.0%, 63.2%, 34.0%, 37.3%, 98.1%, 97.6%, 2.9%, 32.1%, 32.5%, 13.4%, 8.6% and 40.2%, respectively; there was no statistically significant difference in entB, mrkD or fimH between the two groups (P>0.05), the positive rate of irp2 was higher in the blaKPC-positive group than that in the blaKPC-negative group (P<0.05), and the positive rates of the rest virulence-related genes were lower in the blaKPC-positive group than those in the blaKPC-negative group (P<0.05). The rate of HvKP in the blaKPC-negative group was higher than that in the blaKPC-positive group (38.3% vs. 18.0%, P<0.05). As a marker of HvKP, iucA showed high sensitivity and specificity (90.9% and 97.7%), followed by p-rmpA2 (83.6% and 100.0%) and iroN (73.6% and 99.2%). ST11 accounted for 87.4% in the blaKPC-positive group, while ST23, ST20, ST54 and ST29 were the four primary types in the blaKPC-negative group, accounting for 23.4% totally.ConclusionsDifferent virulence genes mean different distributions in KP. blaKPC-negative KP is more virulent than blaKPC-positive KP. iucA and p-rmpA2 could serve as good predicators of HvKP. Armed with extreme virulence and drug-resistance, blaKPC-positive HvKP is of great clinical concern.
ObjectiveTo evaluate the effect of ZnPP Ⅸ on the expressions of heme oxygenase-1 (HO-1) and glutathione-Stransferase-π （GST-π） and the chemosensitivity of drug-resistant hepatic carcinoma cell line Bel/Fu, and explore it’s possibility to reverse drug-resistance and the relevant regulating mechanism. Methods①MTT assay was adopted to detect the drug sensitivity for adriamycin, mitomycin, and 5-fluorouracil of Bel/Fu cell after ZnPP Ⅸ being induced for 24 h. ②RTPCR was carried out to detect the expressions of HO-1 and GST-π mRNA after Bel/FU cells being treated with different concentrations ZnPP Ⅸ for 24 h. ResultsAfter Bel/Fu cells being treated with ZnPP Ⅸ for 24 h, the 50% inhibiting concentration (IC50) for drugs was decreased dramatically （Plt;0.05）. Meanwhile, the expressions of HO-1 and GST-π mRNA in the treated cells also decreased dose-dependently (Plt;0.01). ConclusionsZnPP Ⅸ can increase the chemosensitivity of Bel/FU cells by down-regulation of HO-1 and GST-π expression. ZnPP Ⅸ is a potential agent to reverse multidrug resistance of hepatic carcinoma cells.
【Abstract】ObjectiveTo establish adriamycin (ADM) resistant pancreatic cancer cell line SW1990/ADM and to investigate its drug resistance mechanism.MethodsADM-resistant pancreatic cancer cell line SW1990/ADM was obtained by culture of pancreatic cancer cell line SW1990 in vitro with intermittently increasing the concentration of ADM in the culture medium for ten months. After two months of drug free culture, its biological characteristics, drug sensitivity as well as the expression and function of multidrug resistant gene 1 (mdr1) were detected, respectively. ResultsCompared with the parental cell line, SW1990/ADM showed great changes in biological characteristics and developed a cross resistance to various chemotherapy drugs. The drug resistance indexes of cell line SW1990/ADM to ADM, mitomycin, fluorouracil and gemcitabine were 49.60, 7.25, 3.80 and 1.25, respectively. The level of mdr1 mRNA expression in cell line SW1990/ADM was much higher than that of the parental cell line（P＜0.01). ConclusionWe have established adriamycin resistant pancreatic cancer cell line SW1990/ADM with multidrug resistance phenotype, its multidrug resistance is positively relevant to the expression of mdr1.
Objective To explore the clinical epidemiological characteristics of the lung infection after orthotopical liver transplantation. Methods The clinical data included infection morbidity, mortality, infectious times and relative factors, clinical manifestations, the bacterial strains and distributions of the pathogens, the bacterial resistances of the 53 liver transplantation recipients from 2003.3～2006.12 were summarized and analyzed retrospectively. Results Among 53 recipients, 33 developed lung infectious and 6 died .The mobidity was 62.3% and mortality was 18.2%, with a OR of 1.0. Lung infection predominantly occurred in the first month, especially in the first week after transplantation.There were many factors related to lung infections.Various pathogens, especially Klebsialla, Escherichia Coli and Staphylococus Hominis were isolated from sputum, airway suction drainages and throat swabs. Most of the G- bacteria were sensitive to aminoglycosides,β lactam and lactamase compounds and carbapenems while G+ bacteria were sensitive only to glycopeptides. All the bacteria were resistant to quinolones, β lactams of third and forth generation. Conclusions After liver transplantation, the morbidity and mortality of the lung infections are high.The infections develope at earlier stage, manifest nontypical clinical features.Many factors are revealed to be relevant to the lung infections,meanwhile, various drug-resistant pathogen strains are isolated.
Objective To investigate the role of long non-coding RNA metastasis-associated in colon cancer 1-antisense RNA （MACC1-AS1）in cisplatin resistant gastric cancer and its possible mechanism. Methods Human gastric cancer cell line BGC823 and cisplatin resistant gastric cancer cell line (BGC823/DDP) were selected as the research objects. BGC823/DDP cells were transfected and divided into negative control group (si-NC group, transfected with si-NC empty plasmid) and MACC1-AS1 gene silencing group (si-MACC1-AS1 group, transfected with si-MACC1-AS1 plasmid). The BGC823 cells were transfected and divided into positive control group (pcDNA-NC group, transfected with pcDNA-NC empty plasmid) and MACC1-AS1 gene overexpression group (pcDNA-MACC1-AS1 group, transfected with pcDNA-MACC1-AS1 plasmid). MTT was used to detect the inhibition and 50% inhibition concentration (IC50). Flow cytometry was used to detect apoptosis. Real-time fluorescence quantitative PCR was used to detect the mRNA expression levels of MACC1-AS1, B-lymphoma-2 gene (Bcl-2), Bcl-2 related X gene (Bax), mammalian target of rapamycin (mTOR), phosphorylated mTOR (p-mTOR), protein kinase B (AKT), and phosphorylated AKT (p-AKT). Western blot was used to detect the protein expression levels of Bax, Bcl-2, p-mTOR, mTOR, AKT, and p-AKT. Results The relative expression level of MACC1-AS1 mRNA in BGC823/DDP cells was higher than that in BGC823 gastric cancer cells (P<0.01). The relative expression level of MACC1-AS1 mRNA in the si-MACC1-AS1 group cells was lower than that in the si-NC group cells (P<0.01). The relative expression level of MACC1-AS1 mRNA in the pcDNA-MACC1-AS1 group cells was higher than that in the pcDNA-NC group cells (P<0.01). The cell growth inhibition rate and IC50 of the si-MACC1-AS1 group were higher than those of the si-NC group (P<0.01). The cell growth inhibition rate and IC50 of the pcDNA-MACC1-AS1 group were lower than those of the pcDNA-NC group (P<0.01). The mRNA and protein relative expression levels of Bcl-2, p-AKT/AKT and p-mTOR/mTOR in the pcDNA-MACC1-AS1 group were significantly higher than those in the pcDNA-NC group (P<0.01). The relative expression levels of Bax protein and mRNA in the pcDNA-MACC1-AS1 group were significantly lower than those in the pcDNA-NC group (P<0.01). The apoptosis rate of the pcDNA-MACC1-AS1 group was significantly lower than that of the pcDNA-NC group (P<0.01). The mRNA and protein relative expression levels of Bcl-2, p-AKT/AKT and p-mTOR/mTOR in the si-MACC1-AS1 group were significantly lower than those in the si-NC group (P<0.01). The relative expression levels of Bax protein and mRNA in the si-MACC1-AS1 group were significantly higher than those in the si-NC group (P<0.01). The apoptosis rate of the si-MACC1-AS1 group was significantly higher than that of the si-NC group (P<0.01). Conclusions MACC1-AS1 highly expresses in cisplatin resistant gastric cancer cells. Overexpression of MACC1-AS1 regulates AKT/mTOR pathway mediated apoptosis and enhances cisplatin resistance of gastric cancer cells.
Objective To investigate the drug resistance and homogeneous analysis of Acinetobacter baumanii in emergency intensive care unit ( EICU) . Methods Four multidrug-resistant Acinetobacter baumannii ( MDR-Ab) strains isolated fromnosocomial inpatients fromJuly 25 to September 7 in 2009 were collected and tested for drug sensitivity and MIC determination as well. The A. baumannii isolates were typed with pulsed-field gel electrophoresis ( PFGE) to determine whether they derived fromthe same clone.Results Four isolates from nosocomial inpatients were resistant to multiple antibiotics including carbapenem. The PFGE types identified from four isolates were A and B. The A. baumannii isolates did not derived from the same clone. Conclusion The prevalence of nosocomial infection is not due to transmission of the same strains among different individuals in EICU.