Objective To explore the overall outcome and its factors of patients with carbapenem-resistant Pseudomonas aeruginosa bloodstream infection (CRPA-BSI). Methods A single-center, retrospective cohort study was carried out. The demographic and clinical data of all emergency patients and inpatients in West China Hospital of Sichuan University from 2017 to 2021 were collected. Firstly, the prognosis of patients with CRPA-BSI was compared with those with carbapenem-sensitive Pseudomonas aeruginosa bloodstream infection (CSPA-BSI). Then Cox regression was used to analyze the factors affecting the prognosis of CRPA-BSI patients. Results A total of 53 patients with CRPA-BSI and 175 patients with CSPA-BSI were enrolled, and they were 1∶1 matched according to the age-adjusted Charlson Comorbidity Index (aCCI) to control for confounding factors. When aCCI was similar, the incidence of poor prognosis in CRPA-BSI patients was significantly higher than that in CSPA-BSI patients [41.5% vs. 18.9%; relative risk=2.20, 95% confidence interval (CI) (1.16, 4.19), P=0.011]. The median length of hospital stay in the CRPA-BSI group was 3 d longer than that in the CSPA-BSI group but the difference was not statistically significant (29 vs. 26 d, P=0.388). With regard to prognostic factors, univariate Cox regression analyses showed that the highest temperature ≤39℃ (P=0.014), hepatobiliary and pancreatic diseases (P=0.011), days of central venous catheterization (P=0.025), days of indwelling urinary catheters (P=0.037), adjustment of medication duration according to drug sensitivity results (P=0.015) and Pitt bacteremia score (P=0.007) were related to the poor prognosis of CRPA-BSI patients. Multiple Cox regression analysis showed that hepatobiliary and pancreatic disease [hazard ratio (HR)=3.434, 95%CI (1.271, 9.276), P=0.015] and Pitt bacteremia score [HR=1.264, 95%CI (1.057, 1.510), P=0.010] were independently associated with poor outcome in CRPA-BSI patients. Conclusions The prognosis of CRPA-BSI patients is worsen than that of CSPA-BSI patients. Hepatobiliary and pancreatic diseases significantly increase the risk of poor outcome in CRPA-BSI patients. Pitt bacteremia score is a predictor of prognosis in patients with CRPA-BSI.
ObjectiveTo investigate the impact of postoperative application of Pseudomonas aeruginosa injection on recurrence free survival (RFS) and overall survival (OS) in patients with abnormal serum calcitonin levels following surgery for medullary thyroid carcinoma (MTC). MethodsA retrospective collection of data was conducted for 214 patients with abnormal serum calcitonin levels following MTC surgery at West China Hospital of Sichuan University from January 2015 to April 2024. Propensity score matching (1∶2) was utilized to match patients’ data to reduce confounding bias, comparing RFS and OS between patients who used (Pseudomonas group) and did not use (control group) Pseudomonas aeruginosa injection. ResultsAfter propensity score matching, 72 patients with abnormal postoperative calcitonin levels were included, with 24 in the Pseudomonas group and 48 in the control group. The median follow-up time for the 72 patients was 66 months (11–168 months). The 1-year RFS rates for the Pseudomonas group and the control group were 100% and 75.0%, respectively, and the 2-year RFS rates were 87.5% and 56.3%, respectively. The RFS in the Pseudomonas group was superior to that in the control group (χ2=4.791, P=0.029). The 5-year OS rates for the Pseudomonas group and the control group were 90.9% and 93.5%, respectively, with no significant difference between the two groups (χ2=0.469, P=0.491). The Cox proportional hazards regression model indicated that the median RFS was extended in the Pseudomonas group [25 months vs. 21 months, RR=0.350, 95%CI (0.135, 0.900), P=0.029], but there was no significant impact on OS [66 months vs. 69 months, RR=2.22, 95%CI (0.229, 21.444), P=0.503]. ConclusionPostoperative use of Pseudomonas aeruginosa injection in MTC patients with abnormal serum calcitonin level shows significant improvement in RFS, but no significant change in OS.
Objective To explore the role of CD4+CD25+ Treg cells in chronic pulmonary infection caused by Pseudomonas aeruginosa(PA).Methods Sixty SD rats were randomly divided into a PA group and a control group(n=30 in each group).Chronic lung infection model was established by implantation of silicone tube precoated with PA into the main bronchus.Twenty-eight days later Treg cells in peripheral blood were measured by fluorescence-activated cell sorting（FACS）.Levels of IL-10 and TGF-β in serum were assayed by ELISA.The expression of Foxp3 mRNA in spleen was measured by RT-PCR.Pathological changes of lung tissue were studed by HE staining.Results Treg/CD4+ T cells in the PA group were significantly more than those in the control group[（19.79±6.45）% vs （5.15±0.47）%，Plt;0.05].The levels of IL-10 and TGF-β were (231.52±54.48)pg/mL and （121.05±7.98）pg/mL in the PA group respectively，which were significantly higher than those in the control group[（35.43±23.56）pg/mL and （36.02±8.94）pg/mL].The expression of Foxp3 mRNA in the PA group was significantly higher compared with the control group(0.80±0.044 vs 0.25±0.054，Plt;0.05）.HE staining revealed that PA caused a intensive inflammatory reaction with lymphocytes infiltration.Conclusion CD4+CD25+ Treg cell is up-regulated and plays an important role in chronic lung infection caused by Pseudomonas aeruginosa.
Objectives To retrospectively analyze the isolation rate and drug-resistance of pseudomonas aeruginosa in Fuwai Hospital of Chinese Academy of Medical Sciences from 2013 to 2016. Methods The specimens were collected and cultured. If the isolated bacteria were from the same part of the same patient, the first isolated strains were only counted. The isolated pathogens were identified and the drug-resistance were analyzed. Results A total of 1 404 pseudomonas aeruginosa were isolated. The majority of them were from postoperative recovery room of surgery department (62.1%) and ICU of internal medicine (22.3%). The specimen source were mainly from respiratory tract (75.7%), followed by blood (10.0%) and venous catheter (5.5%). The resistance rate of piperacillin and piperacillin/sulbactam to pseudomonas aeruginosa was 0.6% to 10.4%. The resistance rate of ceftazidime and cefepime was 0.3% to 11.7%. The resistance rate of imipenem and meropenem was 7.6% to 20.1%. The resistance rate of amikacin, gentamicin, and tobramycin was 0.3% to 3.2%. The resistance rate of ciprofloxacin and levofloxacin was 0.6% to 5.2%. Conclusions The isolates of pseudomonas aeruginosa are mainly from postoperative recovery room of surgery department and ICU of internal medicine . Imipenem and meropenem are not the best choices for pseudomonas aeruginosa infection. It has great value to combine piperacillin, piperacillin/sulbactam, ceftazidime and cefepime with aminoglycoside or quinolone antibiotics for the treatment of pseudomonas aeruginosa infection which will reduce drug resistance.
Objective To describe and compare the distributions of aminoglycosides modifying enzymes ( AMEs) in imipenem-resistant Pseudomonas aeruginosa ( IRPA) collected from5 cities in China. Methods A total of 146 strains of IRPA were collected from 5 cities of China ( Chengdu, Hangzhou, Beijing, Shanghai, and Guangzhou) . The polymerase chain reaction ( PCR) were used to amplify the genes of AMEs in IRPA. Results Six positive genotypes were amplified out of 16 genotypes of AMEs by PCR. The total positive rate of AMEs is 65. 06% . The positive rates of genes of aac( 3) -Ⅱ, aac( 6′) -Ⅰ, aac( 6′) -Ⅱ, ant( 2″) -Ⅰ, ant ( 3″) -Ⅰ and aph( 3′) -Ⅵ were 33. 6% , 15. 8% , 19. 9% , 28. 8% , 14. 4%, and 4. 8% , respectively. The genotypes of AMEs were discrepant in different areas as 6 genotypes in Huangzhou and Shanghai, 4 genotypes in Chengdu and Beijing, and 3 genotypes in Guangzhou. Conclusion The results show that the positive rate of AMEs genes is high in IRPA, and the distribution is discrepant among different areas.
Objective To establish a rat model of chronic pulmonary infection by inoculating Pseudomonas aeruginosa to Sprague-Dawley(SD) rats.Metods Sixty SD rats were divided into 2 groups,ie.the P.aeruginosa group and the control group. Silicone tube precoated with P.aeruginosa was placed into the main bronchus. For the control group, sterile silicon tube was intubated. Results P ． aeruginosa was detected from lung tissue of rats in infected groups.Bacterial number was higher than 103cfu ／ g 28 days after inoculation.The pathological study showed fibrinous proliferation and granulomas formation in the lungs of infected rats 28 days after inoculation.Microscopy examination showed a inflammation predominantly with lymphocyte infiltration.In control group, no bacterial and pathological changes could be detected. Conclusions The animal model with P.aeruginosa chronic pulmonary infection can be established successfully by silicone tubes precoated with P.aeruginosa intubated into the main bronchus.
ObjectiveTo explore the relationship between imipenem-resistant Pseudomonas aeruginosa (IRPA) and outer membrane porin protein OprD2 gene mutation.MethodsIRPA strains (n=30) and imipenem-sensitive Pseudomonas aeruginosa strains (n=30) isolated from the clinical specimens in the First Affiliated Hospital of Chengdu Medical College from December 2018 to December 2019 were collected. Bacteria identification and drug sensitivity experiments were performed by VITEK-2 Compact combined with Kirby-Bauer method. Quantitative real-time polymerase chain reaction was used to detect the expression levels of OprD2 gene in the imipenem-resistant group and the imipenem-sensitive group, and then the strains with decreased expression were sequenced.ResultsThe expression level of OprD2 gene in the imipenem-resistant group was significantly lower than that in the imipenem-sensitive group (P=0.048). Compared with the X63152 sequence, all the 11 Pseudomonas aeruginosa strains with significantly decreased OprD2 expression carried genetic variation, which occurred in coding regions. The variation sites presented diversity. The missense mutation of c.308C→G, c.344A→C, c.379G→C, c.471G→C, c.508T→C, c.553G→C, c.556-558CCG→GGC and c.565-566TG→AC caused amino acid change in the loop L2 and L3 of OprD2 porin, which affected the binding to imipenem. In addition, the mutations at 127, 169-171, 175, 177, 604, 628-630, 688, 719, 785, 826, 828, 842-843, 886, 901, 928-930, 934, 936, 944-945, 1039, 1041 and 1274 all resulted in the changes of amino acid. We also detected a deletion (c.1114-1115delAT) and other nonsense mutations. Large fragment deletion of OprD2 gene occurred in Strain 12. ConclusionsThe mutation and deletion of OprD2 gene can reduce the expression lever of OprD2 gene, leading to the resistance to imipenem of Pseudomonas aeruginosa. The variation of OprD2 gene of IRPA from clinical strains is diverse.
Objective To examine the effects of Pseudomonas aeruginosa(PA)quorum-sensing systems on airway mucus hypersecretion．Methods Sixty Sprague-Dawley rats were intubated with a silicone tube pre-coated with PAO1(wild-type PA strain)，PAO1-JP2(quorum-sensing-mutant strain)or saline in the bronchus．After 28 days，the mRNA and protein expression of MUC5AC in the rats’bronchial epithelia were detected by RT-PCR，alcian blue／periodic acid—Schif(AB／PAS)staining and enzyme linked immunosorbent assay(ELISA)．Results In the PAO1 group，bronchiolar epithelium goblet cells by AB／PAS staining was significantly more than those in the PAO1-JP2 and control groups(both Plt;0．05)．The expression level of MUC5AC mRNA in the PAO1 group was significantly higher than those in the PAO1-JP2 and control groups(both P lt;0．05)．The ELISA showed that the concentration of MUC5AC protein in bronchoalveolar lavage fluid(BALF)in the PAO1 group was much higher than that in the PAO1-JP2 group(P lt;0．05)．Conclusion PA quorum-sensing system plays an important role in airway mucus hypersecretion