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Objective To investigate the distribution and antibiotic resistance of pathogens isolated from inpatients with urinary tract infections.Methods A retrospective analysis was carried out on 1033 strains of pathogens isolated from urine culture in patients with urinary tract infections in Zhejiang Xiaoshan Hospital during January 2009 and December 2011.Urine specimens were cultured with Uricult,and K-B method was used for drug susceptibility test,WHONET 5.6 software was used to analyse drug susceptibility test.Results Among 1033 strains of pathogens,681 (65.9％) were gram-negative bacteria,197 (19.1％) were gram-positive bacteria,and 155 (15.0％) were fungi.The three most prevalent bacteria were Escherichia coli (402 strains,38.9％),Klebsiella pneumoniae (74 strains,7.2％) and Candida albicans (64 strains,6.2％).60.7％ (244/402) of Escherichia coli and 45.9％ (34/74) of Klebsiella pneumoniae were extended-spectrum β-lactamases (ESBLs) positive.Escherichia coli and Klebsiella pneumoniae were susceptible to imipenem,meropenem,cefoperazone/sulbactam,piperacillin/tazobactam and amikacin.Enterococcus and staphylococcus were susceptible to vancomycin,linezolid and furadantin.Candida was sensitive to flucytosine,voriconazole and amphotericin B.Conclusion Gram-negative bacteria mainly E.coli is the predominant pathogen to urinary tract infections in this group of patients.Regular analysis and monitoring of pathogen species and drug resistance is important for rational use of antibiotics.
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Objective To investigate the prevalence of plasmid-mediated quinolone resistance qnr and aac(6')-Ib-cr in Enterobacteriaceac in Chiha.Methods A total of 197 clinical isolates with ciprofloxacin≥0.25μg/ml,cefotaxime≥2.0μg/ml and ceftriaxone≥2.0 μg/ml were screened from the 421 non-repetitive clinical isolates of Enterobac teriaceae(Escherichia coli,Klebsiella pneumoniae,Citrobacter freundii,and Enterobacter cloacae)from the nine teaching hospitals in China.qnrA,qnrB,qnrS and aac(6')-Ib gene were detected by PCR.aac(6')-Ib-cr gene was further identified by the digestion with BtsCI followed by sequencing.Conjugation experiments were done.The MIC of ciprofloxacin and other antibacterial agents in donor strain and acceptor strain were determined by agar dilution.Results Qnr was present in 42%(83/197)of isolares,and among these,17 isolates carried qnrA(9%),46 isolates carried qnrB(23%),24 isolates carried qnrS(12%),2 isolates carried qnrA and qnrB,and 2 isolates carried qnrB and qnrS.aac(6')-Ib was present in 46%(90/197)of isolates,40%(36/90)of which carried the cr variant responsible for low-level ciprofloxacin resistance.18 isolates carried qnr and aac(6')-Ib-cr.Qnr wag present in 66% of Enterobacter cloacae isolates,66% of Klebsiella pneumoniae isolates,63% of Citrobacter freundii isolates,and 6% of Escheriehia coil isolates,respectively,aac(6')-Ib-cr was present in 9% of Enterobacter cloacae isolates,22% of Klebsiella pneumoniae isolates,27% of Citrohacter freundii isolates,and 17% of Escherichia coil isolates,respectively,qnr and aac(6')-Ib-cr were present in 20% (83/421)and 9% (36/421) of all isolates respectively. The 13 transconjugants showed 16 to 125 fold increases in the MICs of ciprofloxacin and 16 to 31 fold increases in the MICs of levofloxacin relative to that of the recipient Conclusion Transferable plasmid-medlated low level quinolone resistance associated with qnr and aac(6')-Ib-cr widely exists in the enterobacteriaceae strains and perhaps this may contribute to the rapid increase of bacterial resistance to quinolones in China.
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Objective To study the distribution of the specific fragment R049 of uropathogenic E. coli(UPEC) 132 in UPEC and fecal E. coli strains. Methods The specific fragment R049 was amplified by PCR from 20 UPEC strains and 40 fecal E. coli strains, and 5 genes encoding virulence factors (papC, fimH, hly, aer, cnf1) were detected from fragment R049 positive strains. Pulse field gel electronphoresis (PFGE) was applied for isolating the Xba Ⅰ restriction fragments of the genomes of fragment R049 positive strains, and then Southern blot was applied for analyzing the distribution features of the positive hybridization bands by digoxin-labeled R049 ORF probe. Results The specific fragment R049 was amplified from 8 of 20 UPEC strains (40%) and 3 of 40 fecal E. coli strains (7.5%), and statistics analysis showed significant difference (P<0.01). The specific fragment 11049 was closely related with 5 virulence factors of UPEC in the fragment R049 positive strains. Southern blot showed the sizes of positive bands were 150 kb, 15 kb and 240 kb in 3 fecal E. coli strains, 350 kb in 6 of 8 UPEC strains, and 280 kb and 25 kb in the rest two UPEC strains. Conclusion The specific fragment R049 of UPEC132 possessed the feature of clustering distribu-tion in domestic isolated UPEC strains.
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Objective To investigate immunoprophylactic potential of genetic engineering vaccines of enterohaemorrhagie Escherichia coli O157:H7 in BALB/c mice after immunization with these vaccines. Methods Sixty BALB/c mice (3 weeks old) were randomized averagely into 5 groups. Group 1-3 were im-munized respectively with IntiminC300, Stx2B and HIyAN436, group 4 with a combination of these three vaccines, and group 5 with PBS. Each mouse was immunized with vaccine(100 μg)and Al(OH)3 adjuvant (100 μg) for 3 times. After 7 d of the second and third immunization, serum of each mouse was collected and the different antibodies were detected. After 10 d of the last immunization, all mice were given drinking water containing streptomycin for 3 d before and following oral challenge with O157:H7 (109 CFU), and treated with clinical, microbiological and pathological examination. Results The three vaccines elicited high titer antiserum, and some mice were died after infection with O157. The livability of group 1-4 was re-spectively 73%, 64%, 36% and 91%. And these vaccines depressed fecal and colon shedding with O157. Condusion IntiminC300, Stx2B and HIyAN436 have certain protective efficacy for infection of O157, and combined immunization was more effective than single vaccine.