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Objective:To report the results of national surveillance on the distribution and antimicrobial resistance profile of clinical Gram-negative bacteria isolates from bloodstream infections in China in 2022.Methods:The clinical isolates of Gram-negative bacteria from blood cultures in member hospitals of national bloodstream infection Bacterial Resistant Investigation Collaborative System（BRICS）were collected during January 2022 to December 2022. Antibiotic susceptibility tests were conducted by agar dilution or broth dilution methods recommended by Clinical and Laboratory Standards Institute（CLSI）. WHONET 5.6 and SPSS 25.0 software were used to analyze the data.Results:During the study period，9 035 strains of Gram-negative bacteria were collected from 51 hospitals，of which 7 895（87.4%）were Enterobacteriaceae and 1 140（12.6%）were non-fermenting bacteria. The top 5 bacterial species were Escherichia coli（ n=4 510，49.9%）， Klebsiella pneumoniae（ n=2 340，25.9%）， Pseudomonas aeruginosa（ n=534，5.9%）， Acinetobacter baumannii complex（ n=405，4.5%）and Enterobacter cloacae（ n=327，3.6%）. The ESBLs-producing rates in Escherichia coli， Klebsiella pneumoniae and Proteus spp. were 47.1%（2 095/4 452），21.0%（427/2 033）and 41.1%（58/141），respectively. The prevalence of carbapenem-resistant Escherichia coli（CREC）and carbapenem-resistant Klebsiella pneumoniae（CRKP）were 1.3%（58/4 510）and 13.1%（307/2 340）；62.1%（36/58）and 9.8%（30/307）of CREC and CRKP were resistant to ceftazidime/avibactam combination，respectively. The prevalence of carbapenem-resistant Acinetobacter baumannii（CRAB）complex was 59.5%（241/405），while less than 5% of Acinetobacter baumannii complex was resistant to tigecycline and polymyxin B. The prevalence of carbapenem-resistant Pseudomonas aeruginosa（CRPA）was 18.4%（98/534）. There were differences in the composition ratio of Gram-negative bacteria in bloodstream infections and the prevalence of main Gram-negative bacteria resistance among different regions，with statistically significant differences in the prevalence of CRKP and CRPA（ χ2=20.489 and 20.252， P<0.001）. The prevalence of CREC，CRKP，CRPA，CRAB，ESBLs-producing Escherichia coli and Klebsiella pneumoniae were higher in provinicial hospitals than those in municipal hospitals（ χ2=11.953，81.183，10.404，5.915，12.415 and 6.459， P<0.01 or <0.05），while the prevalence of CRPA was higher in economically developed regions（per capita GDP ≥ 92 059 Yuan）than that in economically less-developed regions（per capita GDP <92 059 Yuan）（ χ2=6.240， P=0.012）. Conclusions:The proportion of Gram-negative bacteria in bloodstream infections shows an increasing trend，and Escherichia coli is ranked in the top，while the trend of CRKP decreases continuously with time. Decreasing trends are noted in ESBLs-producing Escherichia coli and Klebsiella pneumoniae. Low prevalence of carbapenem resistance in Escherichia coli and high prevalence in CRAB complex have been observed. The composition ratio and antibacterial spectrum of bloodstream infections in different regions of China are slightly different，and the proportion of main drug resistant bacteria in provincial hospitals is higher than those in municipal hospitals.
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Objective:To investigate the bacterial distribution of secondary infection and the status of drug resistance in hospitalized patients of hematology department.Methods:The clinical data of 1 125 inpatients in the Hematology Department of the Affiliated Hospital of Xuzhou Medical University from January 2015 to December 2019 were retrospectively analyzed, and the distribution of infectious pathogens and the status of drug resistance of these inpatients were analyzed.Results:A total of 9 335 microbial samples from 1 125 inpatients were submitted for examination, among which 1 349 were positive samples. Among 1 349 positive samples, the gram-negative bacteria-positive samples accounted for 66.4% (895/1 349) and the gram-positive bacteria-positive samples accounted for 33.7% (454/1 349); the blood samples accounted for 44.7%(603/1 349), the sputum samples accounted for 33.9% (457/1 349), and the urine samples accounted for 9.4%(127/1 349). The isolated bacteria whose proportion ranked as the top 3 were Escherichia coli (31.0%), Staphylococcus aureus (21.0%) and Klebsiella pneumoniae (18.0%). The drug resistance rate of Escherichia coli to ceftriaxone was as high as 77.2%, and that of Staphylococcus aureus and coagulase-negative Staphylococcus to benzoxicillin was 58.2% and 66.7%, but both had no resistance to vancomycin.Conclusions:There are a wide variety of infectious pathogens in hospitalized patients of hematology department, and the Escherichia coli and Klebsiella pneumonia are predominant. More attention should be paid to antibiotic prescribing training for clinicians to optimize and standardize the use of antibiotics.
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Objective@#To investigate the clinical and microbiological characteristics of Myroides odoratimimus producing MUS-1 carbapenemase. @*Methods@#A strain of gram-negative bacterium isolated from the urine sample of one patient hospitalized in the oncology department of Affiliated Hospital of Xuzhou Medical University was identified by the Vitek 2 automatic microbial analyzer and 16S RNA sequencing, and its bla MUS-1 gene was detected with PCR. The minimum inhibitory concentrations (MICs) of antimicrobial drugs were determined by the broth dilution method. @*Results@#One strain of MUS-1 carbapenemase producing Myroides odoratimimus was found. The drug susceptibility test showed that it was resistant to most of antibiotics conventionally used, but sensitive to minocycline and meropenem, the MIC of imipenem was 8 μg/mL, which was judged as intermediate. @*Conclusion@#The bla MUS-1 gene may be the cause leading Myroides odoratimimus to resistant carbapenems drugs.
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Objective To understand the prevalence of resistance gene and homology of carbapenem-resistant Klebsiella pneumoniae (CRKP) isolated from ICU of emergency.Methods A total of 19 CRKP isolates were obtained from emergency ICU of the Affiliated Hospital of Xuzhou Medical University from July 2015 to August 2016.PCR was performed to screen the genes encoding carbapenemase,extended spectrum beta-lactamase (ESBL) and AmpC.Pulsed field gel electrophoresis (PFGE) and multi-locus sequence typing (MLST) were used for molecular typing of these bacterial strains.Results Among the 19 CRKP,carbapenemase-resistant genes were detectable in 18 CRKP isolates,including 17 isolates of harboring blaKPC gene and 1 strain of harboring blaNDM gene.All the 18 strains carried ESBLs genes which were identified as 8 blaSHV-12,3 blaSHV-11,5 blaSHV-2a,15 blaTEM-1,10 blaCTX-M-65,3 blaCTX-M-15,1 blaCTX-M-14 and 1 blaCTX-M-27.The 13 strains harboring cephalosporin-resistant genes were all identified as blaDHA-1.PFGE results revealed that the 19 CRKP strains were grouped into 4 types (A,B,C and D) and 4 subtypes(A1,2,3 and 4):A1 (n =12),A2(n =1),A3 (n=1),A4(n=1),B(n=2),C(n=1) and D(n=1).MLST showed that ST11 was the predominant sequence type (n=15) among the 19 CRKP strains,and ST48 (n =2),ST37 (n =1) and untyped (n =1) were also identified.The 15 blaKPC-2-producing CRKP ST11 clone shared the A type of PFGE pattern.Conclusion The report on CRKP suggested the dissemination of blaKPC-2-producing ST11 clone was existed in the ICU of emergency department in this hospital.The surveillance for drug-resistance and effective disinfectant quarantine measures should be strengthened.
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Objective To identify the drug resistance-related genes in a clinically isolated strain of Enterobacter cloacae.Methods A strain of Enterobacter cloacae was isolated from sputum of a patient with chronic obstructive pulmonary disease from the Affiliated Hospital of Xuzhou Medical University in March 2013.Modified Hodge test and metal enzyme inhibition test were performed for drug-resistant phenotype screening.Carbapenemase genes blaMUS-1, blaVIM-1, blaVIM-2, blaIMP, blaKPC-2, blaNDM-1, blaOXA-48 and blaGESwere amplified by polymerase chain reaction (PCR), and the positive products were sequenced and analyzed.Plasmid conjugation and transformation experiments were used to confirm that the resistance gene mediated by plasmids.Agar dilution method was used for antibiotic susceptibility test.Results Both modified Hodge test and metal enzyme inhibition test were positive in this strain of Enterobacter cloacae.blaNDM-1 gene and blaKPC-2 gene were detected by PCR, and further confirmed by sequencing.blaNDM-1 gene was carried by IncX plasmid with 54×103 bp, KPC-2 gene was carried by untyping plasmid with 42×103 bp.The strain was only sensitive to tetracycline (MIC=2 μg/mL) and tigecycline (MIC=1 μg/mL).The symptoms were improved after the patient was treated by tigecycline combined with Piperacillin/Tazobactam.Conclusion blaNDM-1 and blaKPC-2 genes in Enterobacter cloacae can be mediated by plasmids, and appropriate therapy for its infection should be based on the result of antibiotic susceptibility test.
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Objective To evaluate the applicationof the double-disk synergy test(DDST) and combined disk test(CDT) in clini cal metal enzyme phenotype deteetion.To evaluate the value of multiplex PCR in detecting the metallo-β-1actamase in clinical.Methods 56 strains of metallo-β-1actamase-positive strains were identified [NDM-1(n=9),VIM(n=32),IMP(n=15)]for appraise the two methods.By optimizing the design of PCR primers,3 pairs of primers were designed and detected (IMP,VIM,NDM-1) in one tube for evaluate the method.Results The DDST was 80.36％(45/56),and 100.00％(56/56) in the CDT.The accuracy of multiplex PCR was 100.00 ％ (56/56),and the size of the amplified fragment was used to distinguish three types of metallo-β-lactamase.Conclusion The CDT is more suitable for clinical application than DDST.Multiplex PCR has the characteristics of simple,rapid and accurate in detection of metallo-β-1actamase.It is suitable for daily use of clinical microbiological laboratory,which will help the clinical timely and effective administration.
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Objective To evaluate the applicationof the double-disk synergy test(DDST) and combined disk test(CDT) in clini cal metal enzyme phenotype deteetion.To evaluate the value of multiplex PCR in detecting the metallo-β-1actamase in clinical.Methods 56 strains of metallo-β-1actamase-positive strains were identified [NDM-1(n=9),VIM(n=32),IMP(n=15)]for appraise the two methods.By optimizing the design of PCR primers,3 pairs of primers were designed and detected (IMP,VIM,NDM-1) in one tube for evaluate the method.Results The DDST was 80.36％(45/56),and 100.00％(56/56) in the CDT.The accuracy of multiplex PCR was 100.00 ％ (56/56),and the size of the amplified fragment was used to distinguish three types of metallo-β-lactamase.Conclusion The CDT is more suitable for clinical application than DDST.Multiplex PCR has the characteristics of simple,rapid and accurate in detection of metallo-β-1actamase.It is suitable for daily use of clinical microbiological laboratory,which will help the clinical timely and effective administration.
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Objective To analyze the epidemiological characteristics of brucellosis for improving its clinical and laboratory diag‐nostic ability .Methods The clinical and laboratorial data of the patients with brucellosis in our hospital from January 2013 to Sep‐tember 2015 were retrospectively analyzed .Results In 39 cases of brucellosis ,the majority had the sheep‐contacting history and the clinical manifestations were mainly fever (100 .0% ) ,bone and joint pain(64 .1% ) ,hidrosis(51 .3% ) ,weak(33 .3% ) ,lymph node en‐largement(23 .1% ) and hepatosplenomegaly(12 .8% ) .The laboratory detections showed the abnormal liver function ,rapid erythro‐cyte sedimentation rate(ESR) ,hypersensitive C ‐ reactive protein(hs‐CRP)increase ,lymphocytes percentage increase ,positive for brucellosis antibody agglutination test ,positive blood culture or medulloculture ,which was identified as Brucella melitensis by bacte‐riology .Conclusion The clinical manifestations of brucellosis are diversity and is easy to be misdiagnosed .The sporadic cases in northern Jiangsu area are increased year by year .The epidemiological clue should be paid attention to and the recognition on brucel‐losis should be strengthened .The patients with fever of undetermined origin should be conducted the blood culture and brucellosis antibody agglutination test as early as possible .
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Objective To investigate the mechanism related to reduced antibiotic sensitivity of Acinetobacter baumannii inducted by meropenem in vitro.Methods Three strains of clinically isolated carbapenems-sensitive Acinetobacter baumannii were induced by meropenem in vitro, and the mutant strains (MS1, MS2 and MS3) were obtained.Minimal inhibitory concentrations (MICs) of antimicrobial agents to strains before and after induction were determined by automatic drug sensitivity analyzer .The homology of strains was analyzed by Enterobacterial repetitive intergenic consensus -polymerase chain reaction ( ERIC-PCR).Modified Hodge test and EDTA-Na2-double disk synergy test were used to detect carbapenemase and metallo-β-lactamase (MBL), respectively.Main carbapenemase genes were detected by PCR and followed by DNA sequencing.Expressions of adeB and outer membrane proteins in strains before and after induction were detected with fluorescence quantitative PCR and SDS -polyacrylamide gel electrophoresis , respectively.t test was used for data analysis .Results The sensitivity of mutant Acinetobacter baumannii strains to meropenem and most antibiotics was reduced , except to imipenem, amikacin and polymyxin; and the reduced sensitivity to meropenem in MS2 and MS3 was of genetic stability.ERIC-PCR showed 100%homology between the mutant strains and parental strains .Both carbapenemase and metallo -β-lactamase were negative in mutant strains and parental strains , and only OXA-51 gene was found.The expressions of adeB gene in mutant strains were 24.26 ±0.91, while those in parental strains were 22.81 ±0.38, and the difference was not significant (t =2.534, P >0.05).Outer membrane protein with molecular weight 54 000 was missing in MS1, while that with molecular weight 47 000 was missing in MS2 and MS3.Conclusion Reduced antibiotics sensitivity in meropenem -induced Acinetobacter baumannii may be correlated with the deficiency of outer membrane protein with molecular weight 47 000.
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OBJECTIVE To investigate the characteristics and risk factors of nosocomial infection(NI) in patients with hematological malignancies(HM),and provide the bases for making the controlling measures of NI.METHODS Using the targeted monitoring to study NI in patients with HM,and recording 14 factors such as the time of hospitalization,chemotherapy,count of leukocyte and absolute neutrophil count(ANC) and so on.The data were analyzed with unifactorial ?2 test and multifactorial Logistic-regression analysis.RESULTS Among 242 patients with HM the prevalence of NI was 35.5%(86/242) and the prevalence of NI time-cases was 52.9%(128/242).Among 86 patients of NI there were 27 patients occurred multiple sites NI(31.4%).The main infection sites were upper respiratory tract,gastrointestinal tract,lower respiratory tract,oral cavity and blood.66.7% Of NI happened in the period of chemotherapy and 7 days after chemotherapy.The time of hospitalization and ANC were independent risk factors of NI in patients with HM.CONCLUSIONS The patients with HM are susceptible population of NI,and NI often occurs in the period of chemotherapy and 7 days after chemotherapy.So medical staff should strengthen monitoring,and shorten the time of patient hospitalization and of recovery of ANC to reduce the prevalence of NI efficiently.
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OBJECTIVE To analyze the bacterial distribution and drug resistance in lower respiratory tract nosocomial infection(NI).METHODS To investigate 351 patients suffered from lower respiratory tract NI using the prospective monitoring methods,and doing the pathogenic bacterium cultivation for sputums of 351 patients and then taking the susceptibility test.RESULTS Totally 346 pathogenic bacteria were found in sputums of 351 patients.The major pathogenic bacteria were Pseudomonas aeruginosa,Escherichia coli,Klebsiella and Staphylococcus aureus.ESBLs were 36.0% and 40.0%,respectively in E.coli and Klebsiella,and MRSA were 82.1% in S.aureus.Drug resistances were common in Gram-negative bacilli(GNB) and Gram-positive cocci.Piperacillin/tazobactam and cefoperazone/sulbactam and imipenem were the most sensitive for GNB,S.aureus,S.epidermidis and Enterococcus were all sensitive to vancomycin.CONCLUSIONS Drug resistance of the pathogenic bacteria in lower respiratory tract NI is common,so it′s necessary to emphasize pathogenic bacterium monitoring and use the antibacterials exactly.
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0.05).The average rate of three times NI prevalence surveys was 5.23% and that of NI prospective overall(monitoring) method in the same months was 6.60%,the statistical difference between them was found(P