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OBJECTIVE To investigate the treatment plan for az treonam-resistant metallo- β-lactamase（MBL）-producing Enterobacteriaceae infection in pediatric solid organ transplant recipients. METHODS The clinical data of aztreonam-resistant MBL-producing Klebsiella pneumoniae caused intra-abdominal infection of an infant after liver transplantation were retrospectively analyzed. Abdominal infection occurred after operation. The pathogenic bacterium was MBL-producing K. pneumoniae . The drug sensitivity results showed that the infant was resistant to aztreonam. Based on the results of sensitivity test ，polymyxin B combined with tigecycline were selected as initial regimen. The treatment effect was poor ，with recurrent disease and shock spots. The clinical pharmacist assisted the clinician to formulate treatment regimen of ceftazidime avibactam 0.5 g，q8 h combined with aztreonam 0.18 g，q6 h. Relevant domestic and foreign literature were reviewed ，and the treatment plan of MBL-producing Enterobacteriaceae infection after solid organ transplantation was summarized. RESULTS & CONCLUSIONS The infant was finally cured and discharged with ceftazidime avibatan combined and aztreonam. Several foreign literature reported that ceftazidime avibactam combined with aztreonam could effectively treat the infection caused by aztreonam-resistant MBL-producing Enterobacteriaceae infection in patients with organ transplantation. It is expected to be an effective treatment for aztreonam-resistant MBL-producing Enterobacteriaceae infection in pediatric solid organ transplant recipients.
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Objective:To investigate the antimicrobial resistance characteristics of carbapenem-resistant Enterobacteriaceae （CRE） isolated from outpatients with diarrhea in Shanghai， and provide support for surveillance， prevention and control of CRE. Methods:A total of 800 fecal swabs of the outpatients with diarrhea were collected from 23 sentinel hospitals for diarrhea pathogen surveillance in Shanghai from January 2018 to December 2019. The drug-resistant strains were isolated using MacConkey plates containing 1 μg/μL meropenem. The collected strains were identified preliminarily by the VITEK-2 Compact system and VITEK mass spectrometry. The minimum inhibitory concentration （MIC） of the strain was determined by the broth microdilution method. The multi-locus sequence typing （MLST） method and pulsed-field gel electrophoresis （PFGE） were used to analyze the homology of drug-resistant strains. The transferability of the resistance gene was investigated by a junction experiment. High-throughput sequencing was used to characterize the isolates. Results:Seven non-repetitive CRE isolates were multi-drug resistant carbapenem-resistant Escherichia coli （CREC） strains that produce New Delhi metallo-β-lactamase （NDM） with resistance to several commonly used antibiotics in clinical therapy. The molecular typing results showed that the CRE strains had different sequence types， and diverse PFGE patterns. The stains were all positive for blaNDM genes， including blaNDM-5 and blaNDM-13， with blaNDM-5 as the main type. The carbapenem-resistant genes could be transferred to EC600 by conjugation. Conclusion:The intestinal carbapenem-resistant strains in this study are all NDM-producing Escherichia coli. The isolates carried blaNDM and other resistance genes. The MLST analysis showed that they belonged to different cloning types. Antimicrobial resistance genes could be horizontally transferred to EC600 by conjugation.
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Background: Carbapenem resistance in Gram Negative Bacilli is an emerging threat in tertiary care centers which is mediated by Metallo-β-lactamase (MBL) enzyme. As per the National committee for Clinical Laboratory Standards (NCCLS), still does not have documented standard procedure from there several screening methods to detect their enzyme. Some subcontinents of India still awaiting to see prevalence and screening methods to detect enzyme which is responsible for Carbapenem Resistance. Aim: The present study was undertaken to early detection of MBL by screening methods in Gram Negative Bacilli isolated from hospital and the prevalence MBL production in carbapenem resistant bacterial isolates. Materials and methods: 176 consecutive different Gram Negative Bacilli (GNB) isolated from hospitalized patients which were tested antimicrobial susceptibility for different antibiotics including Carbapenem drugs as Imipenem by Kirby Bauer Disc Diffusion (CLSI 2010) and screening of Metallo-β-lactamase production by method as Imipenem- EDTA combined disc synergy test (ICDST) and Imipenem-Double Disc Synergy Test (I-DDST) which determine the MBL by zone size enhancement with EDTA Impregnated Imipenem. Munesh Kumar Sharma, Dakshina Bisht, Shekhar Pal. Detection of Metallo-β-lactamase producing Gram Negative Bacteria in clinical isolates in Tertiary care Hospital - A prospective study. IAIM, 2019; 6(4): 107-111. Page 108 Results: Out of 176 Gram Negative Bacilli, 20.45% (n=36) of isolates were resistance to Imipenem by disc diffusion method and 94.44% (n=34) by DDST EDTA impregnated Imipenem and 88.89% (n=32) showed enhancement of zone size ≥7 mm with EDTA impregnated Imipenem CDST. Imipenem susceptible bacteria strains did not show any enhancement with EDTA impregnated antibiotic disc. Conclusion: Critically ill patient’s therapy is cause of concern for MBL mediated imipenem resistance gram Negative Bacilli. Two methods used for supplementary support in treatment of patients. In both methods of detection DDST is more effective.
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Background@#Extended-spectrum β-lactamase (ESBL)-producing Escherichia coli (E. coli) and Klebsiella pneumoniae (K. pneumoniae) are the important pathogens causing pneumonia. This study aimed to investigate the clinical characteristics and molecular epidemiology of ESBL-producing E. coli and K. pneumoniae causing pneumonia at a large teaching hospital in China.@*Methods@#We collected patient’s clinical data and ESBL-producing E. coli and K. pneumoniae strains causing pneumonia (from December 2015 to June 2016) at a hospital in Wuhan. The susceptibilities, multi-locus sequence typing, homologous analysis, ESBL genes by polymerase chain reaction and sequencing were determined.@*Results@#A total of 59 ESBL-producing strains (31 E. coli and 28 K. pneumoniae) isolated from patients with pneumonia were analyzed. The majority of strains were isolated from patients were with hospital-acquired pneumonia (37/59, 62.7%), followed by community-acquired pneumonia (13/59, 22.0%), and ventilator-related pneumonia (9/59, 15.3%). The E. coli ST131 (9 isolates, 29.0%) and K. pneumoniae ST11 (5 isolates, 17.9%) were the predominant sub-types. The most prevalent ESBL gene was CTX-M-14, followed by SHV-77, CTX-M-3, SHV-11, and CTX-M-27. At least 33 (55.9%) of the ESBL-producing strains carried two or more ESBL genes. The ISEcp1 and IS26 were found upstream of all blaCTX-M (CTX-Ms) and of most blaSHV (SHVs) (57.6%), respectively. Moreover, three ESBL-producing K. pneumoniae ST11 strains which were resistant to carbapenems carried the blaNDM-1 and blaKPC-2, two of which also bearing blaOXA-48 were resistant to all antibiotics (including Tigecycline).@*Conclusions@#Hospital-acquired pneumonia is more likely correlated with ESBL-producing E. coli and K. pneumoniae. ESBL-producing E. coli ST131 and multi-drug resistance ESBL-producing, as well as New Delhi metallo-β-lactamase-1 (NDM-1) and Klebsiella pneumoniae carbapenemases-2 (KPC-2) bearing K. pneumoniae ST11 are spreading in patients with pneumonia in hospital.
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Non Fermenter Gram negative bacilli (NFGNB) has emerged as important hospital pathogens they are more significant as they are found to be multi drug resistant. Resistance to carbapenems is common among NFGNB. AIMS & OBJECTIVES: To isolate & identify NFGNB from various clinical samples and to detect resistance to carbapenem in isolates resistant to Imipenem. MATERIAL & METHOD: NFGNB isolated from various samples were speciated using standard tests. Isolates resistant to Imipenem were subjected to detection of MBLs(Metallo-β-lactmase) and Amp-C. RESULTS: Out of 1566 samples received, NFGNB were 200. Among them 112 were Pseudomonas aeruginosa from which 31 were found to be resistant to Imipenem, of which 3 were MBLproducer by Modified Hodge test while 4 were MBLproducer by EDTAdisc synergy test. Out of 200 NFGNB 71 were Acinetobacter baumanii, of which 23 were found to be resistant to Imipenem, of which 6 were MBLproducer by Modified Hodge test, while 4 were seen to be MBL producer by EDTAdisc synergy test. Nineteen isolates of Acinetobacter baumanii were found to be resistant to cefoxitin of which 6 were found to be Amp-C producer by Amp-c disc test. None of the Pseudomonas aeruginosa were Amp-C producer. Other NFGNB isolated were either sensitive to Imipenem or if resistant were not MBLor Amp-C producer.
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The New Delhi metallo-β-lactamase-1 (NDM-1) was first reported in 2010, detected in a Klebsiella pneumoniae isolate from a Swedish patient of Indian origin. It has recently attracted extensive attention for its biological activities to catalyze the hydrolysis of almost all of β-lactam antibiotics. The gene for NDM-1 can spread from one strain of bacteria to another by horizontal gene transfer. The most troubling aspect is that there are currently no clinically available inhibitors to block the metallo-β-lactamase action. Therefore, there is urgent need to develop new NDM-1 inhibitors, which can protect β-lactam antibiotics from the hydrolysis effect of NDM-1. In this review, the current research, drug-assistant mechanism and potential NDM-1 inhibitors are summarized.
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OBJECTIVE: To explore the bacteriostasis and plasmid elimination activities of different extracted parts of traditional Chinese medicine Radix Scutellariae Baicalensis on NDM-1 Acinetobacter calcoaceticus. METHODS: Thein vitro antibacterial effect of the extracts from Radix Scutellariae Baicalensis was studied. Inhibition zone and minimum inhibitory concentration(MIC) of the alcohol extract and water decoction were examined by using MH agar plates and microdilution susceptibility testing. The growth curve of the NDM-1 Acinetobacter calcoaceticus was tested after being incubated with alcohol extract and water decoction at sub-MIC. At three time points after incubation with different extracts at sub-MIC, photocopy dish method was used to screen plasmid-cured strains of NDM-1 Acinetobacter calcoaceticus. The plasmid-elimination rates and phenotypic changes were compared. RESULTS: Both the alcohol extract and water decoction of Radix Scutellariae Baicalensis inhibited the growth of NDM-1 Acinetobacter calcoaceticus. The MICs were 1.56 mg·mL-1 for the alcohol extract and 6.25 mg·mL-1 for the water decoction. The growth curve showed that the antibacterial effect of the alcohol extract was more obvious. Both the alcohol extract and water decoction of Radix Scutellariae Baicalensis had some degrees of plasmid elimination effect. The plasmid-elimination rates in the alcohol extract group were higher than those in the water decoction group. The plasmid-elimination rates were 61.27% for the alcohol extract and 49.78% for the water decoction, respectively. CONCLUSION: Radix Scutellariae Baicalensis can inhibit the growth of NDM-1Acinetobacter calcoaceticus and eliminate the drug-resistant plasmid effectively and has the potential to be used to control the spread of pan-drug resistant Acinetobacter strains or be an adjuvant treatment method for clinical infections. Its alcohol extract has better effect.
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Objective To investigate the drug resistant mechanism and homology of three strains of carbapenem-resistant Klebsiella pneumoniae (K.pneumoniae) isolated from different sites of one patient.Methods Three strains of carbapenem-resistant K.pneumoniae were isolated from femoral vein catheter tip,wound secretions and sputum of a patient with severe burns,respectively.Their carbapenemase,metallo-β-lactamase (MBL) and drug resistance genes were detected by modified Hodge test,double-disk synergy test and combination disk diffusion and PCR,respectively,and homology and biological typing were analyzed by enterobacterial repetitive intergenic consensus-PCR (ERIC-PCR) assay and multilocus sequence typing (MLST) technology,respectively.Results The carbapenemase and MBL of three strains of carbapenem-resistant K.pneumoniae were negative and positive,respectively.The blaNDM-1 gene was identified from the three strains,but other drug resistance genes such as blanC,blaGES,blaIMP,blaSPM,blaVIM,blaGIM and blaOXA-48 were not detected.ERIC-PCR showed that three isolates belonged to the same genotype,and MLST showed that they were type ST17.Conclusion Carring blaNDM-1 gene is the main cause leading to the drug resistance of three strains of carbapenem-resistant K.pneumoniae,and they belong to the same genotype.
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OBJECTIVE:To provide reference for rational use of antibiotics in the clinic of our hospital. METHODS:Drug re-sistance of Gram-negative bacillus in the inpatients of our hospital were analyzed retrospectively during May 2013-Dec. 2015 as well as the situation of producing metallo-β-lactamase(MBLs). RESTUTS:A total of 2089 strains of Gram-negative bacillus were detected in our hospital during 2013-2015,among which there were 1456 strains of enterobacteria (69.70%) and 633 strains of non-fermentative bacteria,mainly involving Escherichia coli,Pseudomonas aeruginosa,Klebsiella pneumoniae,Acinetobacter bau-mannii and Enterobacter cloacae. A total of 406 strains of carbapenems-resistant bacteria were detected (19.44%),including 367 strains of non-fermentative bacteria and 39 strains of enterobacteria. The resistant rates of carbapenems-resistant strains to 16 antibi-otics were all higher than 50%,but those of non-carbapenems-resistant strains were in relative low level. Except for aztreonam,re-sistant rates of carbapenems-resistant strains to other 15 antbiotics were all higher than those of non-carbapenems-resistant strains, with statistical significance(P<0.05). A total of 36 strains of producing MBLs were detected(8.87%),including 13 strains of pro-ducing MBLs drug-resistant P. aeruginosa and 23 strains of producing MBLs drug-resistant A. baumannii;producing MBLs drug re-sistant enterobacteria had not been found. CONCLUSIONS:Gram-negative bacillus are mainly enterobacteria in our hospital;car-bapenems-resistant strains are mainly non-fermentative bacteria,resistant rate of them are commonly higher than that of non-drug-re-sistant strain. The situation of producing MBLs is serious,and enzyme producing strains are mainly non-fermentative bacteria. It is necessary to strengthen drug resistance of pathogen and enzyme producing strain monitoring,avoid the generation and spreading of drug-resistant strains due to irrational use of antibiotics.
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Introduction: Infections due to multidrug‑resistant (MDR) pathogens are a medical challenge. There is considerable apprehension among clinicians regarding pathogens reported as carrying New Delhi metallo‑β‑lactamase‑1 (NDM) and Klebsiella pneumoniae carbapenemase (KPC) genes from their patients. In the face of extremely high rates of antimicrobial resistance, it is essential to gauge the clinical significance of isolation of pathogens carrying these genes from clinical samples. This study compares the outcome of patients infected with pathogens carrying NDM/KPC genes versus those without these genes. Methods: The study was conducted over a 1‑year period at a Level‑1 trauma centre. Hospital‑acquired infections were diagnosed on the basis of CDC’s criteria. The correlation of isolation of a multi‑resistant pathogen carrying KPC or NDM genes with the clinical outcome was ascertained. Results: A total of 276 consecutive patients admitted to the Intensive Care Units/wards of the JPNA Trauma Centre were included in this study. Of the 371 isolates recovered from these patients, 116 were from patients who had a fatal outcome. The difference in prevalence of blaNDM and blaKPC was not significant in any genera of Gram‑negative pathogens isolated from patients who survived versus those who had a fatal outcome. Conclusion: Isolation of MDR pathogens carrying NDM/KPC genes from clinical samples is not always a harbinger of a fatal outcome. Efforts should be made to prevent cross‑transmission of these pathogens.
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Chryseobacterium species are gaining importance as an emerging opportunistic nosocomial pathogen. Limited availability of clinical data necessitates reporting of such isolates. We report a case of nosocomial urinary tract infection by metallo‑β‑lactamase‑producing Chryseobacterium gleum in an elderly diabetic male with chronic renal disease. Identification and antibiotic sensitivity test performed by conventional methods were confirmed by Matrix‑assisted Laser Desorption Ionization Time‑of‑Flight and VITEK‑2 systems, respectively. The patient responded well to intravenous ciprofloxacin therapy
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Background: The ability of microorganisms to evade antibiotic pressure is challenging in healthcare as patients have little or no drug treatment options. Detection of the prevalence of antibacterial resistance pattern helps towards improved antibiotic policy and empirical treatment. Objectives: We carried out antibiogram profiling and documented the prevalence and co-prevalence of New Delhi metallo-β-lactamase (NDM) and extended spectrum β-lactamases (ESBL) encoding genes in urinary Escherichia coli and Klebsiella pneumonia isolates. Materials and Methods: Antibiotic susceptibilities were tested for 241 isolates of E. coli and K. pneumoniae from urine samples collected from out- and hospitalised patients. Polymerase chain reaction (PCR) was carried out on isolates tested positive for phenotypic production of metallo-β-lactamase and ESBL. A multiplex PCR assay was designed to detect the genes. Results: Multiplex PCR assay designed had a limit of detection of 103 CFU/mL in vitro. NDM detected was significantly higher among K. pneumoniae compared to E. coli (69.2% vs. 18.2%; P = 0.001). Of 17, 14 NDM positive isolates also harboured ESBL genes. The co-production of CTX-M + TEM + NDM (3/9; 33.3% and 5/8; 62.5%) was most common in K. pneumoniae and E. coli, respectively while CTX-M + TEM + SHV + NDM was found in one isolate. Of the 156 phenotypically ESBL producing isolates, CTX-M, TEM and SHV was detected by PCR in 85, 53 and 24 isolates, respectively. Conclusion: NDM and ESBL co-producing isolates were both community (64.7%) and hospital (35.29%) acquired among E. coli. Antibiotic resistance can be effectively evaluated by a cost and time effective molecular method, such as the multiplex PCR used in this study, which complement culture and sensitivity tests.
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BACKGROUND: Rapid detection of carbapenemase-producing gram-negative bacilli (GNB) is required for optimal treatment of infected patients. We developed and assessed a new disk carbapenemase test (DCT). METHODS: Paper disks containing 0.3 mg of imipenem and bromothymol blue indicator were developed, and the performance of the DCT were evaluated by using 742 strains of GNB with or without carbapenemases. RESULTS: The paper disks were simple to prepare, and the dried disks were stable at -20℃ and at 4℃. The DCT detected 212 of 215 strains (98.6% sensitivity with 95% confidence interval [CI] 96.0-99.5%) of GNB with known class A (KPC and Sme) and class B (NDM, IMP, VIM, and SIM) carbapenemases within 60 min, but failed to detect GES-5 carbapenemase. The DCT also detected all two Escherichia coli isolates with OXA-48, but failed to detect GNB with OXA-232, and other OXA carbapenemases. The DCT showed 100% specificity (95% CI, 99.2-100%) in the test of 448 imipenem-nonsusceptible, but carbapenemase genes not tested, clinical isolates of GNB. CONCLUSIONS: The DCT is simple and can be easily performed, even in small laboratories, for the rapid detection of GNB with KPC, NDM and the majority of IMP, VIM, and SIM carbapenemases.
Subject(s)
Anti-Bacterial Agents/pharmacology , Bacterial Proteins/metabolism , Bromthymol Blue/chemistry , Drug Resistance, Bacterial , Gram-Negative Bacteria/drug effects , Imipenem/pharmacology , Microbial Sensitivity Tests/methods , Paper , beta-Lactamases/metabolismABSTRACT
Objective To investigate the genotypes and epidemic of metallo-β-lactamase-(MBL )-producing Pseudomonas aeruginosa (P .aeruginosa)in Changsha.Methods P .aeruginosa isolated from seven comprehensive hospitals in Changsha were collected and performed identification and antimicrobial susceptibility testing,pheno-types of MBL were detected with EDTA-disk synergy test and E-test,genotypes were determined by polymerase chain reaction (PCR),homology analysis were conducted by enterobacterial repetitive intergenic consensus PCR (ERIC-PCR).Results Preliminary screening by EDTA-disk synergy test and E-test showed that only 10 of 81 iso-lates were strong positive;PCR result showed that 18 isolates were positive for MBL,11 of which were IMP-9-type MBL,1 was IMP-1-type,and 6 were VIM-2-type.SIM,SPM,GIM,and NDM-1-types were not found.ERIC-PCR showed that 12 strains of IMP-producing P .aeruginosa has multiple types,6 VIM-2-producing strains were of the same type.Conclusion IMP-9 and VIM-2 are main genotypes in P .aeruginosa in Changsha.
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Objective To research a method for detecting metallo-β-lactamase(MBL)to provide the basis for rationally selecting antibacterial drugs in clinic.Methods A total of 104 strains of imipenem-resistant Acinetobacter baumanmii(IRAB)were collected. The MBL phenotype was detected by using the EDTA disk potentiation test and the detection results were compared with the PCR detection results of MBL.Results Among 104 strains of tested IRAB,21 strains were the MBL gene positive by using PCR;24 strains were the MBL gene positive by using the EDTA disk potentiation test.Compared with the PCR detection results,the sensi-tivity of the EDTA disk potentiation test was 95.2% and the specificity was 95.1%.Conclusion The EDTA disk potentiation test for detecting MBL of Acinetobacter baumanmii is simple,credible in the detection results and cheap in cost,which is suitable for the preliminary identification of the MBL-producing Acinetobacter baumanmii in the clinical microbiology laboratory of the primary hos-pitals.
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Objective To investigate the detection of IMP andVIM metallo-β-lactamases (MβLs)genes in clinically iso-lated gram-negative bacteria as well as bacterial resistance toβ-lactam antimicrobial agents.Methods 113 clinically isolated bacteria were performed antimicrobial susceptibility testing by Kirby-Bauer method ,drug-resistant genes IMP and VIM were detected by polymerase chain reaction (PCR),PCR products were sequenced and aligned with BLAST software. Results VIM gene was detected in 1 Pseudomonas fluorescens strain ,IMP gene was detected in 15 strains ,they were Klebsiella pneumoniae (n=6),Acinetobacter baumannii (n=3),Escherichia coli (n=2),Ralstonia picket-tii (n=1),Pseudomonas aeruginosa (n=1 ),Citrobacter amalonaticua (n=1 ),and Enterobacter cloacae (n=1 ). BLAST results showed that VIM gene was VIM-2 subtype,similarity with gene bank was 99%;all IMP genes were IMP-1 subtype,which were highly homologous ,similarity was 98%-99%.Resistant rates of IMP positive strains to ceftriaxone,cefotaxime,cefoxitin,aztreonam and imipenem were all significantly higher than negative strains (all P <0.05).Conclusion IMP genes of different strains are highly homologous,all are IMP-1 type,indi-cating that IMP genes are highly transmissible and can spread among different species of bacteria.IMP genes are related with resistance ofβ-lactam antimicrobial agents.
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Objective To investigate the antibacterial activity of Schisandra to Acinetobacter baumannii including metallo-β-lac-tamase(MBL)-producing and non-MBL-producing stains in vitro.Methods 75 strains of Acinetobacter baumannii were preliminary screened for clinical isolates of MBL-producing strains,to which confirmatory tests of MBL producing were performed.Drug sensi-tivities of the Acinetobacter baumannii to 14 antibacterial drugs were tested.In vitro antibacterial tests was adopted to determine the MIC of schisandra to 75 strains of Acinetobacter baumannii(including MBL and non-MBL-producing Acinetobacter baumannii).Re-sults MBL confirmatory test showed that among the 50 strains selected 38 strains were positive accounted for 76% (38/50).Con-clusion Schisandra has some antibacterial effect on Acinetobacter baumannii especially MBL-producing Acinetobacter baumannii, and can be combined with western medicine in the treatment of Acinetobacter baumannii infection.
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Objective To evaluate Cica-Beta Test kit for detection of metallo-β-lactamase-producing Pseudomonas aeruginosa (PAE)in the clinical microbiology laboratory.Methods A total of 82 imipenem-resistant PAE clinical isolates from litera-ture[5]was dectected to metallo-β-lactamase (MBLs)by PAE-MHT and Cica-Beta Test kit.Results The sensitivity,speci-ficity and accuracy rate of PAE-MHT was 84.6%,97.2% and 97.6%,and the sensitivity,specificity and accuracy rate of Cica-Beta Test kit was 76.9%,100% and 96.3%,respectively.Two methods had a good consistency.Conclusion Two methods are simple,quick for detecting to metallo-β-lactamase-producing Pseudomonas in clinical laboratories.
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Objective To investigate the situation of Pseudomonas aeruginosa strains carrying metallo-β-lactamases and inte-grases in the Second Affiliated Hospital of Harbin Medical University.Methods The phenotype of metallo-β-lactamases were detected by modified Hodge test,double-disc synergy and combination paper method,respectvily.PCR method was used to detecte metallo-β-lactamases genotypes and the integrationⅠ,Ⅱ and Ⅲ.The PCR products of the whole length bla-IMP gene were purified,sequenced and analyzed by Blast.Results Among 62 Pseudomonas aeruginosa strains,metallo-β-lactamases phenotype of 3 by modified hodge test,4 by double-disc synergy test,4 by combination paper method and were all positive 4 of IMP-1 type metallo-β-lactamases of Pseudomonasaeruginosa strains (10%,4/40)were positives by PCR.Inte-grase Ⅰ of 16(40 %,16/40)strains were positives by PCR method in IMP-resistant Pseudomonasaeruginosa,and integraseⅠ of 22.73 %(5/22)were positives in IMP-sensitive Pseudomonasaeruginosa.No other metallo-β-lactamases,integraseⅡandⅢ were detected in this study.Conclusion IMP-type metallo-β-lactamase existed in IMP-resistant Pseudomonasaerugi-nosa isolates of the Second Affiliated Hospital of Harbin Medical University.Most strains carried integraseⅠ,and other re-sistance mechanisms may be associated with multi-drug resistance,so it is important to prevent the Pseudomonasaeruginosa strains which carried metallo-β-lactamases and integrons widely spread in the hospital.
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Objective To determine new delhi metallo-β-lactamase-1 (NDM-1 )gene in strains of gram-negative bacilli with de-creased sensitivity to carbapenems,and to investigate the epidemic situation of strains carrying NDM-1 gene in Guangzhou area. Methods 105 strains of gram-negative bacilli with decreased sensitivity to carbapenems isolated from 201 1 to 2014 were collected. The conserved sequences of NDM-1 gene were screened initially by using polymerase chain reaction(PCR)amplification,and posi-tive strains were confirmed by PCR amplification of the whole sequence.Then NDM-1 gene was cloned into plasmid pUCm-T and sequenced.Results The resistance rates of Enterobacteriaceae bacteria against meropenem,ertapenem and imipenem were 29.09%, 50.91% and 29.09%,respectively.All strains of Acinetobacter baumanii were resistant to meropenem and imipenem.The resist-ance rates of Pseudomonas aeruginosa against meropenem and imipenem both were 88.46%.4 strains were NDM-1 gene positive, including 1 strain of Klebsiella pneumoniae,2 strains of Escherichia coli,1 strain of Enterobacter cloacae.Successful establishment of cloning plasmid pUCm-T-NDM-1 was confirmed by using double enzyme digestion and sequencing.The sequencing results were compared with BLAST,it was showed that the sequences were exactly the same in four cloned plasmids,and sequences of NDM-1 were also exactly the same with those in domestic and foreign.Conclusion Strains of NDM-1 producing gram-negative bacilli exist in Guangzhou area,and whole sequence of NDM-1 gene carried in these strains are exactly the same with those found in foreign.