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Objective To study dIe ESBLs and plasmid-mediated AmpC enzymes in E.Coli and Klebsiella spp. with CLSI ESBL-screening test positive,confirmation test negative but cefepime susceptible.Methods Antimierobial susceptibility testing were performed by Kirby-Bauer(K-B)method.The genes encoding ESBLs and plasmid-mediated AmpC enzymes were detected by PCR Transfer of ESBLs or plagmid-mediated AmpC resistance was studied by conjugation experiments.The homology of donor (E.coli),recipient(E.coli J53)and their transconjugants were analyzed by ERIC-PCR DNA fingerprints of E.coli and Klebsiella pneumoniae were analyzed by PFGE as recommended bv PulseNet protocoL Results Of 18 isolates from Huashan Hospital,11 were E.coli.6 were Klebsiella pneumoniae and 1 was Klebsiella oxytoca.Antimicrobial susceptibility testing indicated all of 18 isolates were positive on the CLSI ESBL screening test but negative on the confirmation test.and all of isolates were susceptible to cefepime(a zoneof-inhibition diameter of≥18 mm wag considered to indicate susceptible).PCR results indicated that 9 of the 11 E.coli isolates predued CMY-2 AmpC enzyme.TEM,SHV,CTX-M,PER,VEB or SFO type β-lactamages were not identified.Of 6 Klebsiella pneumoniae isolates.5 were DHA-1 AmpC-producing strains.4 of the 5 DHA-1 AmpC-producing strains were coexistence of broad-speetrumβ-lactamaae or extended-spectrumβ-lactamase.including two producing SHV-11 and two producing CTX-M-14 and SHV-62 type ESBL respectively.One Klebsiella oxytoca wag also DHA-1 AmpC producing strain.Conjugation experiments indicated that both ESBLs and AmpC enzymes could be transfefred from donor to recipient.PFGE indicated that the DNA fingerprints of K.pneumoniae were difierent but seven CMY-2 AmpC-producing E.coli isolates from general surgieal ward were similar.Concluslons The main mechanism of antibiotic resistance in CLSI ESBLs-screening test-positive but eefepime.susceptible E.coli and KIebsiellaspp.is production of plagmid-mediated AmpC enzymes.Some strains produce both AmpC enzyme and ESBLs.Such strains should be reported as resistant to cefepime.The results suggest that laboratories should routinely conduct research on the ESBLs and plnsmid.mediated AmpC enzymes in Enterobacteriaceae in order to report antimicrobial susceptibility testing results more correcdy.
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Objective To investigate the resistance of clinical isolates from Shanghai Huashan Hospital in 2005.Methods Antimicrobial susceptibility test was carried out by Kirby-Bauer method.Results were analyzed according to CLSI 2005.Results Of the 3 896 clinical isolates,gram negative bacilli and gram positive cocci accounted for 68.1% and 31.9% respectively.About 93.2%(465/499)of S.aureus isolates were identified as methicillin-resistant Staphylococcus,94.9%(260/274)of coagulase negative Staphylococcus(CNS)isolates were methicillin-resistant.No vancomycin-resistant strain was found.The resistance rates of E.faecalis and E.faecium to high level gentamicin(120 ?g)were 67.4% and 82.8% respectively.Two strains of VRE were isolated.Both were VanA type.ESBLs-producing strains accounted for 47.6%(206/433)in E.coli and 69.6%(391/562)in Klebsiella spp(K.pneumoniae and K.oxytoca).Isolates of Enterobacteriaceae were still highly sensitive to imipenem and meropenem,resistance rates being 0-4% except Citrobacter isolates,9.1% of which were resistant.However,39.3% and 59.6% of P.aeruginosa strains were resistant to the above carbapenems,respectively.Conclusions The prevalence of MRSA and MRCNS is very high.ESBLs are prevalent in E.coli and Klebsiella spp.Two glycopeptide-resistant E.faecium isolates are identified firstly in Huashan Hospital.Our data will be useful for rational use of antimicrobial agents in the treatment of bacterial infections.
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From the course setting and method of using case-study teaching in the medical microbiology,the article discussed its advantages and disadvantages,finding that carrying out such method can improve students' learning interest,their thinking and discriminating abilities and the humanism,thus giving some new opinions about the reform of the course system in the future.
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AIM: To investigate the expression of interleukin-7(IL-7) in human liver cancer and identify the splice variant of IL-7. METHODS: Reverse transcription-polymerase chain reaction (RT-PCR) was used for investigating the expression of IL-7. According to IL-7 gene cDNA, the primers were designed and synthesized, then the splice variant of IL-7 in human liver cancer cells was identified, cloned into vector and sequenced. RESULTS: The expression of IL-7 mRNA was equal between normal liver tissue and hepatic cancer cells.A new band of IL-7 was obtained from hepatic cancer cells, which lacks exon 4. CONCLUSION: IL-7 gene is expressed highly in both normal liver tissue and hepatic cancer cells. In addition, hepatic cancer cells can produce splicing variant by alternative splicing.
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Objective:To investigate the expression of interleukin-7 in human liver and stomach,identify the splice variants of IL-7.Methods:Reverse transcription-polymerase chain reaction(RT-PCR) was used for investigating the expression of IL-7.According to IL-7 gene cDNA,the primers were designed and synthesized,then the splice variants of IL-7 in human cancer tissues was identify,cloned into vector and sequenced.Results:The results showed that(1)the expression of IL-7 mRNA was nearly equal between human liver and stomach,(2)two new bands of IL-7 was obtained from liver cancer and gastric carcinoma,one lacks exon 4,another exon 5.Conclusion:IL-7 gene is expressed highly in both human liver and stomach.In addition,human liver cancer and gastric carcinoma can produce splicing variants of IL-7 by alternative splicing.