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Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) has become a widely used method in the field of microbial identification. Its obvious advantages including rapidity, great accuracy and high throughput attract many researchers to investigate its potential for usage in other microbiological fields. Currently, several studies have reported MALDI-TOF MS-based analysis of bacterial resistance to antibiotics, which can identify the specific heterogeneous spectrum peaks related to drug resistance through simple visual analysis of the spectrum or more complex analysis of the entire spectrum using informatics methods and statistical approaches. Therefore, MALDI-TOF MS has become a potential tool for detecting antibiotic resistance in bacteria. This review mainly summarized the progress in MALDI-TOF MS-based analysis of bacterial resistance to antibiotics.
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Objective:To investigate the diagnostic value of immunoglobulin M (IgM) and immunoglobulin G(IgG) antibodies to 2019 Novel Coronavirus (2019-nCoV) in 2019-nCoV infection.Methods:This is a retrospective study. Serum samples were collected from 284 patients including outpatients and inpatients in the Renmin Hospital of Wuhan University from January 20 to February 17 in 2020. Among them 205 cases were 2019-nCoV infected patients, including 186 cases confirmed with nucleic acid test and 19 cases diagnosed by clinical symptoms and CT characteristics according to "the New Coronavirus Pneumonia Control Protocol (5th edition)" . A total of 79 subjects with other diseases but negative to 2019-nCoV infection were recruited as control group. Serum IgM and IgG antibodies to 2019-nCoV were measured with fully automated immunoassay technology for all subjects. Statistical significance between 2019-nCoV antibodies test and 2019-nCoV nucleic acid test was determined using the χ 2 tests. Results:The sensitivity of serum IgM and IgG antibodies to 2019-nCoV were 70.24%(144/205) and 96.10%(197/205) respectively and the specificity were 96.20%(76/79) and 92.41%(73/79) respectively. The positive and negative predictive values of 2019-nCoV antibodies were 95.63%(197/206) and 91.03% (71/78) respectively, and the positive and negative predictive values of 2019-nCoV nucleic acid test were 100%(186/186) and 80.61%(79/98) respectively. The total coincidence rate of diagnosing 2019-nCoV infection between antibody tests and nucleic acid test for 2019-nCoV were 88.03%(250/284).Conclusion:Joint detection of serum IgM and IgG antibodies to 2019-nCoV is an effective screening and diagnostic indicators for 2019-nCoV infection, and an effective complement to the false negative results to nucleic acid test.
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Objective@#To investigate the diagnostic value of immunoglobulin M (IgM) and immunoglobulin G(IgG) antibodies to 2019 Novel Coronavirus (2019-nCoV) in 2019-nCoV infection.@*Method@#This is a retrospective study. Serum samples were collected from 284 patients including outpatients and inpatients in the Renmin Hospital of Wuhan University from January 20, 2020 to February 17, 2020. Among them 205 cases were 2019-nCoV infected patients, including 186 cases confirmed with nucleic acid test and 19 cases diagnosed by clinical symptoms and CT characteristics according to "the New Coronavirus Pneumonia Control Protocol (5th edition)" . A total of 79 subjects with other diseases but negative to 2019-nCoV infection were recruited as control group. Serum IgM and IgG antibodies to 2019-nCoV were measured with fully automated immunoassay technology for all subjects. Statistical significance between 2019-nCoV antibodies test and 2019-nCoV nucleic acid test was determined using the χ2 tests.@*Result@#The sensitivity of serum IgM and IgG antibodies to 2019-nCoV were 70.24%(144/205) and 96.10%(197/205) respectively and the specificity were 96.20%(76/79) and 92.41%(73/79) respectively. The positive and negative predictive values of 2019-nCoV antibodies were 95.63%(197/206) and 91.03% (71/78) respectively, and the positive and negative predictive values of 2019-nCoV nucleic acid test were 100%(186/186) and 80.61%(79/98) respectively. The total coincidence rate of diagnosing 2019-nCoV infection between antibody tests and nucleic acid test for 2019-nCoV were 88.03%(250/284).@*Conclusion@#Joint detection of serum IgM and IgG antibodies to 2019-nCoV is an effective screening and diagnostic indicators for 2019-nCoV infection, and an effective complement to the false negative results to nucleic acid test.
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Objective To explore the implementing process and application effect of risk management in blood transfusion compatibility testing.Methods 16 957 patients receiving transfusion therapy along with blood transfusion compatibility testing at our hospital between July,2013 and June,2015 were selected as the control group,without any risk control in place.19 011 patients receiving such therapy yet with blood transfusion compatibility testing between July, 2015 and June, 2017 were selected as the observation group,and managed by the risk management procedure.The risk incidence and satisfactory rate of doctors,nurses and patients were analyzed between the two groups.Results The risk incidence was zero in the observation group, and 0.09% in the control group, indicating the risk incidence rate in the observation group significantly lower than the control group(P<0.05).The satisfactory rate of doctors, nurses and patients in the observation group(98.33%)was significantly higher than the control group (71.25%)(P <0.05).Conclusions Implementing risk management procedure in blood transfusion compatibility testing may effectively prevent and reduce the risk incidence, enhance the satisfactory rate of doctors,nurses and patients,and ensure the clinical transfusion safety.
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Objective To evaluate the value of matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS) in detecting carbapenemases-producing Enterobacteriaceae. Methods Sixty-one carbapenemase-producing Enterobacteriaceae (CPE) and 108 carbapenemase-none-producing Enterobacteriaceae(NCPE) strains that isolated in the Renmin Hospital of Wuhan University from February 2016 to February 2017 were used in this study. Twenty CPE strains and 20 NCPE strains were se-lected and used to establish the optimum reaction system of MALDI-TOF MS for the detection of carbapene-mase-producing Enterobacteriaceae strains. Results The optimal reaction system of MALDI-TOF MS was successfully established:equal volumes of imipenem solution (1 mg/ml) and bacterial suspension (2 Mc-Farland turbidity standard) were first mixed together and incubated at 37℃ for 20 min,and then the super-natant was detected by MALDI-TOF MS after centrifugating. It would be a carbapenemase-producing strain if the peak of (300±0.55) m/z in the mass spectrum of imipenem disappeared completely. MALDI-TOF MS was used to identify carbapenemase-producing Enterobacteriaceae strains among the 169 strains and the result was consistant with that by using carbapenemase gene detection. Conclusion MALDI-TOF MS could accu-rately and rapidly detect carbapenemases-producing Enterobacteriaceae. It could be used as a routine method to provide references for early anti-infective treatment and infection control in hospitals.
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Bacterial resistance has become a serious problem that the whole world is facing.Routine bacterial drug resistance testing methods such as K-B test and dilution method are time-consuming and incapable to identify the specific drug resistance mechanism , which can not meet the needs of clinicians. MALDI-TOF MS overcomes the shortcomings of traditional methods and has broad application prospects in detection of bacterial resistance and drug resistance mechanism.This article reviews the recent progress on the application of MALDI-TOF MS in detection of bacterial drug resistance mechanisms.
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Objective To investigate the tendency of distribution and drug-resistance of the causative organisms of urinary tract infections(UTIs)in Wuhan,and provide reliable evidence for clinical treatment.Methods Analyzed the 5 378 stains of pathogen isolated from the urine of patients in hospital.The bacteria isolates were identified with BD Phoenix-100 while can-dida isolates were identified by color plate.Results A total of 5 378 stains of pathogen had been isolated.There were 2 945 stains (54.8%)of Gram-negative bacteria,1 657 stains (30.8%)of Gram-positive bacteria,776 stains (14.4%)of fungus. The rates of Escherichiacoli resistant to penicillin were highest (>83%),and there were no carbapenem-resistant strains. There were vancomycin and linezolid-resistant Enterococcispp strains,the lowest dection rates of which were 0.3%.The de-tection rate of MRCNS was over 83%.Conclusion Escherichiacoli was the most common pathogens of urinary tract infec-tion,and theβ-lactamase inhibitor complex can be used as empirical treatment of E.coli infections.Thedetection rate of MRCNS increased,which shoud be kept a watchful eye on.
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Objective To investigate the distribution of CYP2C19 metabolism phenotype in patients with clopidogrel treatment in Huangshi.Methods The peripheral blood samples were obtained from 76 patients with clopidogrel treatment in Cardiovascular Department.CYP2C19 genotypes were determined by the gene chip,CYP2C19 metabolism phenotype were investigated and com-pared with the data of healthy Han Chinese from the published papers.Results There were three kinds of metabolizers about the metabolism phenotypes of CYP2C19,which were extensive metabolizers,intermediate metabolizers and poor metabolizers.In the 76 patients,the ratios of these metabolism phenotypes were 39.47%,44.74% and 15.79%,respectively.The result coincided with the healthy Han Chinese.Conclusion The clinical individualized medication of healthy Han Chinese could be refered to the clinical indi-vidualized medication of patients with clopidogrel treatment in Huangshi.
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Objective To explore the effect of hepatitis B virus(HBV) on the expression of apolipoprotein B(ApoB) and its regulatory mechanism. Methods mRNA and protein expression of ApoB in HepG2 and HepG2.2.15 cells was measured by RT-PCR and Western blot, serum ApoB levels in patients with HBV infection and in healthy individuals were measured by biochemical analyzer Olympus 5400, the expression of ApoB difference among healthy individuals, patients with chronic hepatitis B, liver cirrhosis, and hepatocellular carcinoma were analyzed, HBV infectious clone pHBV1.3 was tranfected into HepG2 cells,and expression of ApoB and microsomal triglyceride transfer protein(MTP) was measured by RT-PCR and Western blot. Results Expression of ApoB mRNA and protein was lower in HepG2.2.15 cells than in HepG2 cells, serum apoB levels was much lower in patients with chronic hepatitis B and liver cirrhosis as compared to healthy individuals( P ＜0.05 ), HBV could inhibit the expression of ApoB and MTP at mRNA and protein levels. Conclusion HBV may downregulate the synthesis and secretion of ApoB via inhibits the expression of MTP.
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Objective To investigate the feasibility of a new polyclonal antibody specific to fetal hemoglobin (HbF) and its application in enrichment of circulating fetal nucleated red blood cell(NRBC) for non-invasive prenatal diagnosis. Methods A polyclonal antibody against a synthetic peptide comprising residues 69-78 of the γ-chain of HbF was prepared and conjugated to carrier protein KLH as the immunogen according to the specific antigenic determinant. The peptide-KLH solution was mixed with freund's complete or incomplete adjuvant and immunized goat to prepare specific polyclonal antibody against the γ-chain of fetal hemoglobin. After purification with protein G, maternal blood was obtained from 32 pregnant women at 22 to 39 weeks of gestation. NRBCs were separated and then stained with antibody against the γ chain of HbF. All the positive cells were collected by micromanipulator under microscopic observation, and whole genome was amplified by improved primer extension preamplification (PEP). Multiplex polymerase chain reaction amplification at nine different polymorphic short tandem repeat (STR) loci was also used to determine origin of the positive cells isolated from maternal blood. Results NRBCs stained with antibody against the γ chain of HbF were found in all of the blood from the 32 cases. Attached positive cells with anti-HbF staining have unique morphological characteristics, low nucleus-to-cytoplasm ratio, brown cytoplasm and blue dense nucleus after hematoxylin counterstain under microscopic observation, which can distinguished NRBCs with other cells. A total of 183 NRBCs were found in all of 32 pregnant women at a range of 0.6～1.8 cell/ml venous blood. The accurate rate was 90.6% by the STR genotype identification. Conclusion The antibodies specific to fetal γ-chain of fetal hemoglobin with synthetic peptide technology may have wide clinical utility in identification of fetal NRBCs from maternal circulation for non-invasive prenatal genetic diagnosis.
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Objective To explore distribution and genetypes of plasmid-mediated quionlone resistance genes qnrA.qnrB and qnrS in Enterobacteriaceae isolates iu Renmin Hospital of Wuhan University.Methods The qnrA,qnrB and qnrS genes in Enterobaeteriaceae isolates including nonrepetitive 129 isolates of E.coli.13 isolates of E.cloacae and 37 isolates of k pneunoniae were detected by PCR.Antibiotic suseeptibility testing for 15 antibiotics were also performed by K.B in virto.MICs of ciprofloxacin were determined by agar dilution methed.Plasmid conjugatable test wag applied to examine whether qnrA,qnrB and qnrS genes were located in conjugatable plasmid.For qnr-positive strains,integrase I and SHV-1,TEM-1,CTX-M,OXA-I,OXA-Ⅱ,OXA-Ⅲ,DHA and EBC β-lactamases genes were examined.Results 25 qnr-positive isolates were detected among 179 Enterobaeteriaceae isolates,including 6 qnrA-positive isolates,9 qnrB-positive isolates and 10 qnrS-positive isolates,which were presented in 3.35%.5.02%,and 5.59%respectively.All positive isolates were susceptible to imipenem but resistance to some other drugs.2 qnrA-positive isolates and 4 qnrB-positive isolates of them were susceptible to Quinolones.The plasmid wag eonjugatable in 2 qnrA-positive isolates and 4 isolates carrrying qnrB and qnrS.23 qnrA-positive isolates harbored type 1 Integrase,but one isolate with both qnrB and qnrS did not carry Type 1 Integrage.14 isolates of them were TEM-1 producing strains.6 isolates were OXA-Ⅲ-producing strains.and 7 isolates of them were EBC-producing strains.Conciusions In HuBei province,a low prevalence of qnrA,qnrB and qnrS wag determined in Enterebacteriaceae isolates.Muhidrng-resistance was found in qnr-pesitive isolates and qnr genes were detected in quinolone susceptible strains.Extendedspectrum β-lactamages could be presented in qnr-positive isolates too.
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Objective To study the infection condition of AmpC ? lactamases producing strains for reasonable use of antibiotics in clinic. Methods Adopting modified three dimensional extract test was adopted to detect enterobacteriaceae strains, and 12 antibiotics were determined by the antimicrobial disk diffusion susceptibility tests in specimen collected from 233 senile infectious patients. Results The total isolating rate of AmpC ? lactamases producing enterobacteriaceae strains in senile patients was 8 6%. The incidence of AmpC ? lactamases producing strains was found most often in E.cloacae. The AmpC ? lactamases producing strains were susceptive to imipenem and there the resistance rates to imipenem were 100 0%. The resistance rates to cefepime were 85%～100% to the third generation cephalosporins and aztreonam Conclusions The drug resistance of AmpC ? lactamases producing enterobacteriaceae is very serious. It is important to surveillance and control drug resistance of AmpC producing strains.
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Objective To explore antibiotics resistance profiles and DNA fingerprints of Pseudomonas aeruginosa isolates resistant to imipenem (IRPA). Methods DNA fingerprints of 56 strains isolated from ICU (intensive care unit) were constructed by ERIC-PCR (enterobacter repetitive intergenic consensus-PCR). MICs (minimal inhibitory concentrations) were determined by agar dilution method.Results 33 genotypes were got from 56 strains by ERIC-PCR. Of 8 frequently used antibiotics, 5 of them showed resistance rate higher than 50%. Conclusion It is high time to pay attention to multi-drug resistance of IRPA. The exist of prevalence of IRPA clone in ICU advise us to control of IRPA in hospital effectively.
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Objective To analyze risk factors of nosocomial pneumonias due to ESBL-producing Klebsiella pneumoniae.Methods From July 2001 to December 2004,38 patients with ESBL-producing K. pneumoniae and 63 patients with non-ESBL-producing K. pneumoniae were enrolled. ESBL-producing strains were detected by confirmed test.Results Hospital duration,ICU stay,tracheal intubation or tracheotomy,indwelling catheters,mechanical ventilation and use of cefotaxime were found to be risk factors in the acquisition of K. pneumoniae with ESBLs by univariate analysis. Cefotaxime use remained as risk factors by multivariate analysis with logistic regression. Conclusion The reasonable use of cefotaxime is an important measure to control the prevalence of ESBLs-producing strains of Klebsiella pneumoniae.
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Objective To compare three methods for detecting extend-spectrum ?-latamases (ESBL s) and investigate current resistance of ESBL s.Methods 538 isolates of Enterobacter were detected by VITEK-AMS, compound piece type confirm test, and double-disk synergy test.Results 20.1% (108/538) was found to be ESBL s positive by VITCK-AMS. The positive rate of ceftaxime/clavulanic acid and ceftaxime compound pieces test was 19.5% (105/538). The positive rate of double-disk synergy test was 13.0%. The resistant rate of 12 antibiotics to ESBL s positive strains was significantly higher than ESBL s negative strains.Conclusions It is important to select the proper and rapid method to detect ESBL s in time.
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Objective To investigate the relationship between chronic prostatitis and the coagulase-negative staphylococci (CNS),and to study the diagnostic value and clinical significance of CNS in expressed prostatic secretion (EPS). Methods Overall,428 patients with chronic prostatitis were included in this study.Their mean age was 31 years (range,18 to 46 years).The mean cause was 6 months (range,3 to 32 months).The mean NIH-CPSI score was 23.2.Bacterial culture and antimicrobial agent sensitivity test were applied to samples from the 428 patients.The samples were taken with 4 tubes from the lower urinary tract segmented by Meares-Stamey method. Results Bacteria were found in 248 patients (57.94%) out of 428 ones.Gram-positive bacteria were found in 195 cases(78.63%).In the 195 cases,staphylococci were found in 160 cases(64.25%,160/248).CNS were found in 89 cases(35.89%,89/248),most of which were epidermidis staphylococci 81 cases(32.66%).The next were saprophytic staphylococci 3 cases and hemolytic staphylococci 2 cases.There was no correlation between NIH-CPSI score and bacterial culture results.The sensitivity test results showed the rate of drug resistance of CNS from EPS was high for ?-lactamases,quinolones and aminoglycosides(51.9% to 100%). Conclusions The results suggest that CNS is a main kind of pathogen of chronic prostatitis,so considerable attention should be paid to it.In addition,it is of significant importance to apply bacterial culture and sensitivity test in EPS to the diagnosis and treatment of chronic prostatitis.