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.
Objective To investigate the predictors for carbapenem-resistant Acinetobacter baumannii, Enterobacteriaceae and Pseudomonas aeruginosa (CR-AEP) as the pathogens of bloodstream infection (BSI) for intensive care unit (ICU) patients. Methods A retrospective case-control study based on ICU- healthcare-associated infection (HAI) research database was carried out. The patients who have been admitted to the central ICU between 2015 and 2019 in the ICU-HAI research database of West China Hospital of Sichuan University were selected. The included patients were divided into two groups, of which the patients with ICU-acquired BSI due to CR-AEP were the case group and the patients with BSI due to the pathogens other than CR-AEP were the control group. The clinical features of the two groups of patients were compared. Logistic regression model was used to identify the predictors of BSI due to CR-AEP.ResultsA total of 197 patients with BSI were included, including 83 cases in the case group and 114 cases in the control group. A total of 214 strains of pathogenic bacteria were isolated from the 197 BSI cases, including 86 CR-AEP strains. The results of multivariate logistic regression analysis showed that previous use of tigecycline [odds ratio (OR)=2.490, 95% confidence interval (CI) (1.141, 5.436), P=0.022] was associated with higher possibility for CR-AEP as the pathogens of BSI in ICU patients with BSI, while previous use of antipseudomonal penicillin [OR=0.497, 95%CI (0.256, 0.964), P=0.039] was associated with lower possibility for that. Conclusion Previous use of tigecycline or antipseudomonal penicillin is the predictor for CR-AEP as the pathogens of BSI in ICU patients with BSI.
To observe the changes of intestinal bacteriology in acute necrotizing pancreatitis (ANP). Dog ANP model was induced by injection of sodium taurocholate with trypin into the pancreatic duct. All dogs were sacrificed on the seventh postoperative day, mucosal and luminal microflora of intestine were analyzed quantitatively. The blood and organs were collected for culture. The results showed that population levels of E.coli in the intestinal mucosa and the content in cecum of the ANP dogs showed much higher level than those of the controls (Ｐ＜0.01 or Ｐ＜0.05), while bifidobacterium and lactobacillus were decreased significantly (Ｐ＜0.01), resulting in reversal of bifidobacterium/E.coli ratio. Blood levels of endotoxin were 1-2 times higher in ANP group as compare with the controls. The positive rate of blood and organs were 100% in ANP dogs. E.coli were the major bacteria cultured. The results indicated that microecological disturbance could take place after the onset of ANP, which may take an important role on pancreatic infection complicating ANP.
Protein post-translational modifications (PTMs) are critical for modulating protein structure and function. Among these, lysine lactylation (Kla) has garnered significant attention in recent years as a newly discovered PTM. Although Kla has been thoroughly investigated in eukaryotic systems, its study in prokaryotes, especially bacteria, remains comparatively limited. Emerging research highlights that bacterial Kla, operating through dynamic modification mechanisms, is pivotal in processes such as growth and metabolism, virulence control, pathogenicity, and host-pathogen interactions. This article provides a comprehensive overview of the latest progress in bacterial Kla research, emphasizing its historical discovery, distinct modification features, and underlying molecular regulatory mechanisms. We further explore the regulatory roles of this modification in bacterial physiological processes and pathogenesis, concluding with a discussion of current research challenges and prospective future developments.
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。
ObjectiveTo study the influence of myxobacteria metabolites NX52 and NX83 on the proliferation of colorectal carcinoma cells and investigate its probable mechanism. MethodsThe human colorectal carcinoma cell lines HT-29, SW480, and SW1463 were respectively treated with the two metabolites (NX52 and NX83) at different concentrations (0.1 mg/mL, 1.0 mg/mL, and 10.0 mg/mL), the cells of negative control were treated without metabolite. The proliferation inhibition was examined by methyl tthiazolyl tetrazolium assay. The cell morphology character was compared by inverted microscope, and the apoptosis of cell was analyzed by flow cytometry. ResultsTwo kinds of metabolites NX52 and NX83 had time-dose inhibitory effects on proliferation of human colorectal carcinoma cells HT-29, SW480, and SW1463 (P < 0.05). The metabolite NX83 had more obvious proliferation inhibition in the colorectal carcinoma cells as compared with the metabolite NX52 (P < 0.05). After 48 h, the apoptosis rate of the metabolite NX83 for SW1463 cell was observably increased as compared with the negative control group (P < 0.01). ConclusionsThe two kinds of metabolites NX52 and NX83 from myxobacteria could kill colorectal carcinoma cells in vitro. The possible mechanism might be induced by apoptosis of tumor cells.
In order to inquire into the relation between bacterial L-forms and chronic appendictis,appendices removed from 10 patients with appendicitis were cultured with improved kagans’s solid medium and nutrient medium containing blood respectively.Bacterial forms with bacterial L-form transforms to L-forms and 1 strain of bacillus aerogen with its L-form.The result shows that bacterial form transforms to L-form,then to bacterial form may be related with appendicitis attack,alleviation and attack again.
Objective To investigate the joint effects of selective digestive decontamination (SDD) and glutamine (Gln) on preventing intestinal bacterial translocation of orthotopic piggyback liver transplantation and to observe the incidence of postoperative pneumonia in rabbit. Methods Thirty rabbits received orthotopic piggyback liver transplantation and were randomly divided into three groups (SDD group, SDD+Gln group and control group). Mixed emulsion of tobramycin, polymyxin E and nystatin were given to the rabbits in SDD group. Same dosage of the above components plus Gln were given to the rabbits in SDD+Gln group. Samples of portal vein blood, ileum tissue and lung tissue were obtained in each group at different phases during and after operation, the pathological changes of ileum tissue, the bacterial translocation in blood of portal vein and the incidence of postoperative pneumonia were detected. Results The mixing section area of intestinal blood capillaries in SDD+Gln group was smaller compared with control group (P＜0.05， P＜0.01) and SDD group (P＜0.05) while the portal vein was obstructed for 15, 30 and 45 min, and after the operation, respectively. The length of ileum villus in SDD+Gln group was longer than that in control group (P＜0.05) and in SDD group (P＜0.05) before the portal vein was obstructed, but the length of ileum villus in control group gradually became longer and eventually exceeded that in SDD+Gln group at the time of 45 min after the portal vein was obstructed (P＜0.05). After the operation, the length of ileum villus in SDD+Gln group was significantly longer than that in SDD group (P＜0.05) and control group (P＜0.01). At the time of 45 min after the obstruction of portal vein and 30 hours after operation, the positive rate of cultured bacterial in the blood of portal vein in SDD+Gln group was significantly lower than that in control group (P＜0.05, P＜0.01). The incidence of postoperative pneumonia in SDD+Gln group and SDD group were significantly lower than that in control group (P＜0.05,P＜0.01). Conclusion Gln could nourish intestinal epithelium of mucous membrane.When combined with SDD, it could decreased the incidence of intestinal bacterial translocation occurred during the obstruction of portal vein and after operation, so as to decrease the incidence of postoperative pneumonia.