Objective To analyze the species distribution and resistance of the pathogens isolated fromblood cultures of the patients in intensive care unit ( ICU) , and provide a basis for prevention and control of bloodstream infections in critically ill patients. Methods The data of blood cultures of the patients in ICUduring January 2009 to December 2011 was investigated retrospectively.Results In the last 3 years, positive rate of blood cultures of ICU patients was 15. 4% , 15. 7% , and 17. 6% respectively. Among the isolates, Gram-positive bacteria were predominant ( 52. 3% ) , followed in order by gram-negative bacteria ( 33. 1% ) and fungi ( 14. 7% ) . Aerobe and facultative anaerobe were the predominant bacterial isolates ( 99. 7% ) . Enterococcus faeciumand Staphylococcus spp. were the most common gram-positive bacteria, and 4. 5% of E. faecium isolates were resistant to vancomycin. Rate of methicillin-resistance for S. aureus and S. epidermidis was 73. 5% and 93. 7% respectively. In terms of gram-negative bacteria, Acinetobacter calcoaceticus- A. baumannii complex were the leading species, 96. 9% of the isolates had multi-drug resistance and 14. 1% of the isolates had extra-drug resistance. Klebsiella pneumonia and Escherichia coli isolates were less frequently isolated and those producing extended spectrum beta-lactamases accou ted for 70. 3% and 80. 0% of the isolates respectively. Candida spp. was the most common fungi isolates ( 96. 7% )with an annual change of species distribution and declining susceptibility to azoles.Conclusions Gram-positive bacteria should be the major target for prevention and control of bloodstream infections in critically ill patients. Whereas, more attention should be paid to the infection caused by candida spp. and multidrug resistant gram-negative bacteria.
Objective To investigate the characteristics of the pathogens causing bloodstream infection after general surgery in infant and young children patients, and to provide the references for disease treatment and nosocomial infection control. Methods The clinical and laboratory examination data after general surgery in infant and young children patients, who were admitted to our hospital from January 2012 to March 2017, were retrospectively collected. The pathogens and drug resistance were analyzed by SPSS 18.0 software. Results In this study, 109 cases were included, and 117 strains of the pathogens were isolated, including 53 isolates (45.3%) of gram negative bacteria, 41 isolates (35.0%) of gram positive bacteria, and 23 isolates (19.7%) of fungi. Escherichia coli (16/117, 13.7%), Enterococcus faecium (13/117, 11.1%), Candida parapsilosis (12/117, 10.3%), Klebsiella pneumoniae (9/117, 7.7%) and Enterococcus faecalis (8/117, 6.8%) were the top 5 species. Strains producing extended-spectrum beta-lactamase accounted for 87.5% of E. coli (14/16) and 44.4% (4/9) of K. pneumoniae isolates. Both E. faecium and E. faecalis were susceptible to vancomycin. C. parapsilosis showed the susceptibility to the antifungal agents. Conclusion Gram negative bacteria are predominant pathogens causing bloodstream infection after general surgery in infant and young children patients, and infection caused by resistant isolates should be prevented and controlled.
Objective To systematically review the resistance of pseudomonas aeruginosa to quinolone in China. Methods Such databases as CNKI, WanFang Data, CBM, VIP, PubMed, EMbase and The Cochrane Library were electronically searched from inception to December 2012, for relevant studies on the resistance mechanism of pseudomonas aeruginosa to quinolone. Two reviewers independently screened literature according to inclusion and exclusion criteria. Then, meta-analysis was performed using RevMan 5.0 software. Results Totally 19 studies were included, involving 723 strains of quinolone-resistant pseudomonas aeruginosa. The statistical results showed that, in the areas to the north of Huai River, the detection rates of gyrA, gyrB, parC and parE were 88.0%, 13.3%, 31.4% and 16.7%, respectively; and in the areas to the south of Huai River, they were 64.6%, 50.0%, 35.4% and 16.7%, respectively. The detection rates of plasmid mediated resistant genes aac (6’)-Ib-cr was 0 (0/66) in the areas to the north of Huai River, and 39% (25/64) in the areas to the south of Huai River. The outer membrane protein expression rate of active efflux system was 68.1%. Conclusion In China, gyrA gene mutation and the active efflux system mainly account for pseudomonas aeruginosa’s resistance to quinolone. DNA topoisomerase IV abnormalities and plasmid mediated resistance is the secondary mechanism.
Objective To investigate the characteristics of the pathogens isolated from the cerebrospinal fluid (CSF) and the prognosis of the adult patients with central venous system (CNS) infection, and to provide the basis for disease treatment. Methods The clinical data and findings of the laboratory examination of the patients, who were admitted to West China Hospital of Sichuan University from January 2014 to September 2016, and suffered from CNS infection with the positive results of CSF culture, were retrospectively analyzed. The species distribution and in-vitro susceptibility of the pathogens and hospital mortality were analyzed. Results A total of 157 cases, involving 87 (55.4%) community-acquired cases and 70 (44.6%) hospital-acquired cases, were included. One hundred and fifty-eight strains of the pathogens were isolated from the CSF specimens of these patients, including 73 isolates (46.2%) of gram negative bacteria, 64 isolates (40.5%) of fungus, and 21 isolates (13.3%) of gram positive bacteria. In terms of species distribution,Cryptococcus neoformans was the predominant (62/87, 71.3%) species isolated from the patient with community-acquired infection, whileAcinetobacter calcoaceticus-A. baumannii complex (31/71, 43.7%) was the predominant specie from the patients with hospital-acquired infection. Analysis of the resistance phenotypes showed that all theC. neoformans isolates were susceptible to the antifungal agents. More than 90% ofA. calcoaceticus- A. Baumannii complex isolates were resistant to the regular antibiotics. The resistant rates ofK. pneumoniae isolates to the regular antibiotics were no more than 25%. The hospital mortality of the groups infected by gram-negative bacteria, fungi, and gram-positive bacteria were 52.3% (38/72), 32.8% (21/64), and 19.0% (4/21), respectively. There was statistical difference for the hospital mortality among these groups (P=0.006). Conclusion In our hospital,C. neoformans are the common species isolated from CSF of the patients with community-acquired CNS infection. Gram negative bacilli are commonly isolated from CSF of the hospital-acquired cases. The mortality of patients with gram negative bacilli is high.
Objective To introduce the research progress in the effect of chemotherapeutic resistance of metabolic enzymes of gemcitabine to pancreatic cancer.Methods Recent literatures about metabolic enzymes that played key roles in mediating gemcitabine chemotherapeutic resistance of pancreatic cancer were collected and reviewed. Results The metabolic enzymes of gemcitabine, such as hENT1, dCK, RRM1 and CDA, were closely related to chemotherapeutic resistance of pancreatic cancer. The relationship between the single nucleotide polymorphism of metabolic enzymes and the resistance to gemcitabine remained to be clarified. Conclusion Multiple factors are involved in the mechanism of chemotherapeutic resistance of pancreatic cancer to gemcitabine, which needs further research.
ObjectiveTo explore the risk factors for neonatal nosocomial infection and the pathogen resistance, in order to provide the basis for hospital infection control. MethodsSurveillance of hospital infection in newborns hospitalized for more than 48 hours were carried out from January to December 2012, and the risk factors for hospital infection were analyzed. ResultsThere were 54 newborn cases with neonatal nosocomial infection, and the infection rate of newborns was 1.25%. The major infection sites were respiratory tract (66.7%), gastrointestinal tract (18.5%), skin and soft tissues (9.2%). Birth weight (χ2Trend=126.88, P<0.001), hospitalization days (χ2Trend=106.89, P<0.001), invasive operation (χ2=5.338, P=0.021) were the major risk factors. A total of 54 strains of pathogenic bacteria were isolated from 54 newborn cases with neonatal nosocomial infection. Twenty-three strains of gram-positive bacteria accounted for 42.6%, which were generally resistant to penicillin and large ring lactone class antibiotic drugs. Thirty-one strains of gram-negative bacteria accounted for 57.4%, which were mainly resistant to the three generations of cephalosporins. ConclusionThe hospital infection rate of newborns is low. Birth weight, hospitalization days and invasive operation are the major risk factors for neonatal nosocomial infection.
ObjectiveTo investigate the species and resistance phenotypes of the pathogens causing catheter-associated urinary tract infection (CAUTI) in critically ill patients in West China Hospital of Sichuan University, and to provide the basis for the prevention and treatment of this kind of infection. MethodsThe clinical data and findings of the laboratory examination of the patients, who were admitted to intensive care units and suffered from CAUTI in our hospital during January 2012 to December 2014, were retrospectively analyzed. The pathogens isolates from the urine specimens of the patients with CAUTI and their resistance phenotypes were analyzed. ResultsThree hundred and seventy patients suffering from CAUTI were included in this study. Five hundred and seventeen strains of pathogens were isolated from the urine specimens of these patients, including 222 isolates (42.9%) of fungus, 181 isolates (35.0%) of gram negative bacteria, and 114 isolates (22.0%) of gram positive bacteria. In terms of species distribution, Candida albicans (105 isolates, 20.3%), C.glabrata (78 isolates, 15.1%) and C.glabrata (30 isolates, 5.8%) were the predominant fungus. Among the gram negative bacteria, Escherichia coli (81 isolates, 15.7%), Klebsiella pneumoniae (37 isolates, 7.2%), and Acinetobacter calcoaceticus-baumannii complex (23 isolates, 4.4%) were the main species. Enterococcus faecium (79 isolates, 15.3%) and E.faecalis (13 isolates, 2.5%) were the frequently isolated gram positive bacteria. Analysis of the resistance phenotype showed that the resistance rates to itraconazole, voriconazole and fluconazole of Candida spp. were above 10%. Thirty percent of the isolates of E.coli and K.pneumoniae, and 60% of the isolates of A.calcoaceticus-Baumannii complex were resistant to many of the regular antibiotics. Imipenem resistance rate of A.calcoaceticus-Baumannii complex was 60.8%. Sixty percent of the isolates of E.faecium and E.faecalis were resistant to many of the regular antibiotics. The vancomycin-resistant isolates accounted for 16.5% of E.faecium and 31.0% of E.faecalis. ConclusionCandida species are the major pathogens for CAUTI in critically ill patients in our hospital and show the resistance to azoles. We should focus on the drug resistance of gram negative bacteria and gram positive bacteria. The rational use of antibiotics and application of effective infection control measures are important to decrease the CAUTI.
Objective To study the distribution and drugresistance of pathogens isolated from patients who suffered from lower respiratory infections after thoracotomy and provide basis for rational use of antibiotics in clinical practice. Methods A total of 118 patients suffered from lower respiratory infections after thoracotomy in Beijing Lung Cancer Center and the Thoracic Surgery Department of Xuanwu Hospital between January 1,2006 and December 31, 2009. We performed a retrospective study on pathogens from their lower respiratory tract. Of these patients, 89 are male and 29 are female with a mean age of 64.6 years. Sputum specimens were obtained by sterile sputum collectors or bronchofibroscopes, and then were sent to microorganism laboratory immediately. Cytological screening was carried out before specimen inoculation. Bacterial culture, identification and drug sensitivity test were performed with routine methods. Results A total of 201 strains of pathogens from the lower respiratory tract were identified. There were 126(62.7%) strains of gramnegative bacilli, 66(32.8%) strains of grampositive cocci, and 9(4.5%) strains fungi. The four prevalent gramnegative bacilli strains with the highest isolating rate between 2006 and 2009 included 34(27.0%) strains of acinetobacters, 28(22.2%) strains of verdigris Pseudomonas, 19(15.1%) strains of Klebsiellas and 19(15.1%) strains of Escherichia coli. Verdigris Pseudomonas ranked first in isolating rate among prevalent gramnegative bacilli strains from 2006 to 2008, but it was replaced by cinetobacters (9 strains, 40.9%) in 2009. The most prevalent strains of grampositive cocci were staphylococcus aureus (35 strains, 53%) from 2006 to 2009. Gramnegative bacilli were most sensitive to imipenem and no grampositive cocci were resistant to vancomycin. Conclusion Gramnegative bacilli are the most common pathogens in lower respiratory infections after thoracotomy and show extremely high drugresistance rate. Drugresistance monitoring of pathogens should be promoted. It may contribute to rational antimicrobial therapy and effective control of infections.
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.
【Abstract】Objective To investigate the possible mechanism of gemcitabine resistance in pancreatic cancer chemotherapy. Methods Recent literatures about the genes and signal pathways those play key roles in mediating gemcitabine chemotherapy resistance of pancreatic cancer were collected and reviewed.Results Oncogenes like c-Src and bcl-XL, inflammation pathway of NF-κB, cytokines like IL-1β and NO are closely related with the chemoresistance； the relationship between multiple drug resistance relevant genes like MDR1/P-gP and the resistance to gemcitabine remains to be clarified. Conclusion Genes and pathways like c-Src, bcl-XL, NF-κB, etc. might become new targets to increase the chemotherapeutic sensitivity of pancreatic cancer, however, the mechanism of pancreatic cancer chemotherapy resistance still needs further to be studied.