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Because of the lack of typical clinical manifestations, infection is difficult to be diagnosed in patients with hematological malignancies, resulting in high mortality. Neutrophil CD64 (nCD64) has been used in the early diagnosis of infection for many years and has been proved to be highly sensitive and specific. However, it is rarely used in the diagnosis of hematological malignancies with infection. This paper reviews the main influencing factors and coping methods in the diagnosis of hematological malignancies with infection.
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Objective@#To investigate the drug resistance and positive virulence genes of Acinetobacter baumannii (A.baumannii) and analyze the correlation between drug resistance and the positive pattern of virulence genes. @*Methods@#A total of 67 strains of A.baumannii were collected and identified by matrix assisted laser desorption ionization time of flight mass spectrometry technology (MALDI-TOF MS). Drug susceptibility tests were carried out by turbidimetric and redox indicator method. The homology of A.baumannii stains was explored by cluster analysis. The 8 virulence genes including bacterial outer membrane protein (ompA), biofilm formation (adeH, csuA, pgaA), iron uptake system (basJ), phospholipase D (plcD), capsular positive phenotype (ptk) and regulation of quorum sensing system (abaI) were amplified by PCR and sequenced. The correlation between virulence genes and drug resistance in the 67 strains of A. baumannii was investigated. @*Results@#The positive rates of virulence genes ompA, adeH, csuA, pgaA, abaI, basJ, ptk and plcD were 94%, 100%, 94%, 99%, 93%, 96%, 82% and 99%, respectively. Among the 67 strains of A. baumannii, 3 genes were simultaneously detectable in 1 strain (1.5%), 5 genes were positive in 2 strains (3.0%), 6 genes were positive in 2 strains (3.0%), 7 genes were positive in 14 strains (20.9%) and all the 8 genes were positive in 48 strains (71.6%). Among the 48 strains with 8 positive virulence genes, the drug resistance rate of polymyxin was only 2.1%, but tetracycline was 58.2%, piperacillin and other 13 antibiotics was more than 80%. The 14 strains with 7 positive virulence genes showed more than 78% of resistance rate for all the tested antibiotics except for tetracycline and polymyxin. Cluster analysis showed that the 67 strains of A. baumannii were divided into 2 genotypes: A (41 strains) and B (26 strains). The 41 strains of A type were divided into A1 (27 strains) and A2 (14 strains) subtypes. The strains of A1 subtype were mainly from neurosurgery department (7 strains), ICU (5 strains) and pneumology department (3 strains). The strains of A2 subtype were mainly from pneumology department (3 strains), cardiothoracic surgery department (3 strains), ICU (2 strains) and neurosurgery department (2 strains). The 26 strains of B type were divided into B1 (19 strains) and B2 (7 strains). The strains of B1 type were mainly from ICU (7 strains), neurosurgery department (4 strains) and respiratory department (3 strains). The strains of B2 type were mainly from ICU (2 strains) and respiratory department (3 strains). @*Conclusion@#The cross infection from A. baumannii may present in our hospital. There was no correlation between drug resistance and positive pattern of virulence gene in Acinetobacter baumannii.
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The hospital introduced a multi-department synergy in management of the rational use of carbapenems. Specifically,the medical affairs department conducts training and appraisal of doctors along with a monthly checkup of medical records. The pharmaceutical affairs division conducts prior prescriptions checkup and follow-up comment. The clinical microbiology laboratory and the hospital-acquired infection management department monitors and releases such infection and bacterial resistance information of the whole hospital in real time. The results showed increased prescriptions of imipenem and cilastatin sodium, and decreased prescriptions of biapenem for injection. Drug resistance analysis showed that carbapenem resistant strains increased by 28%,but the total number of patients reduced by 10% and total number of patients with multidrug resistance remained unchanged. It is proposed to further antimicrobial stewardship in the hospital to achieve rational drug use and curb bacterial resistance.
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Objective To evaluate the application of matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF MS) technology in the identification of filamentous fungi,and analyze the susceptibility of filamentous fungi to commonly used antibiotics.Methods A total of 100 strains of filamentous fungi were collected and identified rapidly by MALDI-TOF MS.The obtained results were compared with those from microscopic examination.The susceptibility of filamentous fungi was detected by the Etest method.Results Among 100 strains of filamentous fungi identified by MALDI-TOF MS,61 reached to the species level(score≥2.000),36 to the genus level(score between 1.700 and 1.999),and 3 failed to be identified (score ＜ 1.700).There was inconsistent results for one strain of filamentous fungi between MALDI-TOF MS and microscopic examination.The MIC90 of amphotericin B against Epidermophytonfloccosum was 0.19 μg/mL,while that against Aspergillus flavus was above 32 μg/mL.The MIC90 of itraconazole against Trichophyton tonsurans,Microsporum canis and Epidermophytonfloccosum were all below 0.38 μg/mL,while that against Aspergillus niger was above 32 μg/mL.The MIC90 of fluconazol were above 256 μg/mL for most of strains.The MIC90 of voriconazole and caspofungin against Aspergillus fumigatus,Aspergillus flavus,Aspergillus niger,Trichophyton rubrum,Trichophyton tonsurans and Microsporum canis were ≤0.38 μg/mL and ≤ 1 μg/mL,respectively.Conclusion The MALDI-TOF MS technology may be used to identify the filamentous fungi isolated from clinical specimens quickly,accurately and high-throughput.Voriconazole and caspofungin have effective anti-filamentous fungi activity.
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Objective To explore the clinical value of plasma(1,3)-β-D-glucan detection(G test)in the diagnosis of invasive fun-gal infections(IFI).Methods The plasma samples were collected in 67 cases of IFI,61 cases of non-IFI and 48 healthy controls from January to September 2013.The level of(1,3)-D-glucan in plasma was detected by the kinetic turbidimetric assay and the opti-mal critical value of the G test was determined by receiver operating characteristic curve(ROC).Results The levels of(1,3)-β-D glucan in the IFI,non-IFI and healthy control groups showed the non-normal distribution.However,the median level of plasma(1, 3)-β-D glucan in the IFI group was 208.00pg/mL,which was significantly higher than 61.30 pg/mL(Z =-5.083,P <0.01)in the non-IFI group and 31.16 pg/mL(Z =-8.288,P <0.01)in the healthy control group.The area under ROC of the G test for diag-nosing IFI was 0.846 and the optimal critical value was 90.49pg/mL.The corresponding sensitivity,specificity,positive and nega-tive predictive values were 86.6%,77.1%,69.9% and 90.3%,respectively;at the same time,which of the fungal culture for diag-nosing IFI were 53.7%,94.5%,85.7% and 61.9% respectively.Conclusion Plasma(1,3)-β-D-glucan detection exhibits the high sensitivity and the better negative predictive value for the diagnosis of IFI.But the false positive results occur at times.It is sugges-ted that the G test can be dynamically conducted combined with the fungal culture for improving the efficiency of IFI diagnosis.
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Objective To analyze molecular evolution and binding free energies of cephalosporinase ADC-57.Methods Minimum Evolution method in MEGA 5.0 was used to analyze molecular evolution of cephalosporinase ADC-57 and other 19 kinds of beta-lactamases.Tertiary structure of ADC-57 was predicted by homology modeling referring to tertiary structure of CMY-2.The molecular docking of ADC-57 to 11kinds of beta-lactams substrates was performed using DOCK module in ArgusLab 4.1and the binding free energies (△G) was calculated.Results ADC-57,CMY-2,DHA-1,ADC-7,ADC-56 were all belong to class C beta-lactamase,and molecular evolution between ADC-57 and ADC-56 was closest.The top three antibiotics with declining binding free energy of beta-lactams were ertapenem,cefoxitin and ceftazidine,while the last two were clavulanic acid and aztreonam.Conclusions Catalytic activities of cephalosporinase ADC-57 to ertapenem,cefoxitin and ceftazidine are high,while to clavulanic acid and aztreonam are low. Hydrolytic activities of enzyme to beta-lactams (substrates) can be analyzed by molecular docking.
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Objective To investigate the molecular mechanism of Klebsiella pneumoniae resistant to carbapenem. Methods The minimal inhibitory concentrations ( MICs) of the antimicrobial agents were determined by E-test. The 23 β-lactamase genes and 2 porin genes were amplified by polymerase chain reaction (PCR) , then the products were purified and their sequences were analyzed. Results The MICs of piperacillin, piperacillin/sulbactam, amoxicillin/clavulanic acid, cefoperazone/sulbactam, cefotaxime, cefepime and aztreonam to 5 strains of Klebsiella pneumoniae were all higher than 128 μg/mL, and those of imipenem or meropenem were higher than 32 μg/mL. All isolates carried blaTEM-1 and blaDHA-1 genes. Deletion of ompK35 and ompK36 were observed in Kp01 and Kp03, and the deletion of ompK35 was also observed in Kp02 and Kp05. Base insertion of ompK36 occurred in Kp02, Kp04 and Kp05. Compared with GenBank (GU945384) , ompK35 gene mutations of G→C at base 465 and T → C at base 466 in Kp04 lead to Gln to His substitution at position 155 and Tyr to its substitution at position 156, and it might be a new subtype. Conclusion The production of DHA-1 β-lactamase combined with the loss of OmpK36 or OmpK35 in porin genes may contribute to high-level carbapenem resistance in Klebsiella pneumoniae.
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OBJECTIVE To investigate resistance to antimicrobials and resistant genes associated with ?-lactamases in Escherichia coli isolated from Changzhou district. METHODS Minimum inhibitory concentrations (MIC) of ampicillin,piperacillin,piperacillin/tazobactam,cefotaxime,ceftazidime,cefepime,aztreonam and imipenem were determined by agar dilution. Seventeen resistant genes of E. coli encoding ?-lactamases including TEM and SHV were detected by PCR amplification and sequenced by DNA sequencer. RESULTS The detecting rates of extended-spectrum ?-lactamases in 80 Klebsiella pneumoniae isolates was 46.3%(37/80). Five ?-lactamase resistant genes including TEM,SHV,CTX-M-1group,OXA-1group and DHA in 37 isolates were found,and their rates were 81.1%,78.4%,21.6%,10.8% and 5.4%,respectively. Of 37 strains,at least one ?-lactamase gene was detected in 36 strains. More than two ?-lactamase resistant genes were simultaneously isolated from 24 strains.Furthermore,four ?-lactamase resistant genes were found in one strain.Only one strain wasn't detected out ?-lactamase gene. CONCLUSIONS E. coli has carried various kinds of ?-lactamase resistant genes in Changzhou district,which become the important causes of resistance to ?-lactam antimicrobials.
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OBJECTIVE To investigate resistant genes encoding ?-lactamases and aminoglycoside modifying enzymes in Pseudomonas aeruginosa isolated from clinical specimens,and phylogenetic analysis was performed.METHODS Antimicrobial susceptibility test was performed by PhoenixTM-100 system.Resistant genes encoding ?-lactamases,aminoglycoside modifying enzymes and antiseptic resistance were detected by PCR amplification and verified by DNA sequencer.RESULTS The resistant rates of ?-lactams including ampicillin/sulbactam,piperacillin,piperacillin/tazobactam,cefotaxime,ceftazidime,cefepime,imipenem and meropenem in 190 strains of P.aeruginosa were 98.9%,59.5%,45.8%,77.4%,34.2%,38.4%,15.3% and 6.8%,respectively.Ciprofloxacin and levofloxacin still showed powerful activities with resistance being 15.3% and 21.0%.The positive rates of blaVEB, blaGES and blaCARB genes were 9.5%,9.5% and 57.1% in 21 isolates.Twenty strains lost oprD2 genes.However,the ?-lactamase genes of TEM,SHV,OXA,PER,IMP,VIM,SPM,GIM and DHA were not found.Three resistant genes encoding aminoglycoside-modifying enzymes were found in 21 isolates,such as aac(6′)-Ⅰ,aac(6′)-Ⅱ and ant(2″)-Ⅰ,and they accounted for 9.5%,61.9% and 66.7%,respectively.The positive rate of qacE△1-sul1 genes was 66.7% in 21 isolates.CONCLUSIONS P.aeruginosa isolated in clinic has carried many resistant genes.The loss of oprD2 gene may be the important cause of P.aeruginosa resistant to imipenem.Cluster analysis indicates that the spread of clones occurred in our hospital.
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OBJECTIVE To explore the resistance of Pseudomonas aeruginosa isolated in clinic against five antiseptics involving in povidone iodine(Iodophor),glutaraldehyde,chlorhexidine,symclosene(trichloroisocyanurate) and benzalkonium bromide.METHODS The susceptibility test of P.aeruginosa was determined by PhoenixTM-100 system.Minimun inhibitory concentration(MIC) of povidone iodine,glutaraldehyde,chlorhexidine,symclosene and benzalkonium bromide was detected by liquid dilution method.RESULTS The resistant rates of ampicillin/sulbactam,chloramphenicol,tetracycline and trimethoprim-sulfamethoxazole in 190 isolates of P.aeruginosa were all more than 98.0%.However,P.aeruginosa was to imipenem and meropenem were 15.3% and 6.8%.It was found that P.aeruginosa possessed the most resistant to glutaraldehyde and symclosene with its MIC50 being 32 ?g/ml and 64 ?g/ml.But the MIC50 of chlorhexidine and benzalkonium bromide were only 1 ?g/ml and 2.4 ?g/ml.Meanwhile,time-kill assays indicated that chlorhexidine could still produce rapid and powerful bactericidal effects at a concentration of 1MIC after 10 min treatment.CONCLUSIONS There are distinct differences in P.aeruginosa against povidone iodine,glutaraldehyde,chlorhexidine,symclosene and benzalkonium bromide.It is very important that antiseptics should be used rationally.Measurements should be taken to decrease dissemination of resistant bacteria and prevent nosocomial infection.