Dissertation > Medicine, health > Basic Medical > Medical Microbiology ( pathogenic bacteriology,pathogenic microbiology ) > Pathogenic bacteria > Enteric bacilli

Study on the Virulence Factor of E.coli Isolated from Urine and Its Relationship with Antibiotic Resistance

Author HouMin
Tutor ChenJinYing
School Tianjin Medical University
Course Pathogen Biology
Keywords Pyelonephritic Escherichia coli virulence factor adherence polymerase chain reaction antibiotic resistance
CLC R378.2
Type Master's thesis
Year 2006
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[Objective] To study the distribution of the virulence factors and its relationship to the antibiotic resistance of the Escherichia coli strains isolated from urine. [Methods] All the 81 strains of Escherichia coli were isolated from urine in patients suffered from urinary tract infection and were from 5 hospitals in tianjin from 1992~2004.papC and fimH gene were tested by PCR and Some virulence factors(hly ,cnfl ,aer) by multiplex PCR. Drug sensitivity tests were examed by K-B methods.[Results] Of all the the Escherichia coli strains isolated from urine, the positiverate of the UPEC was 50.6%, non-UPEC was 49.4%. All the other virulence factors were 67.9%.Among the UPEC strains, positive rates to hly,cnf1,aer,and fimH were 63.41%, 34.15%, 60.98% and 53.66%, respectively. Among the non-UPEC strains were 10%,35%,12.5%and5%, respectively. ,There were statistical differences between them(P<0.05).hly and cnf1 both positive were 31.71%.Among the cnf1 positived strains only one strain showed hly negatived,and,87.5% of them had papC gene.86.67% of the hly positived strains had papC gene.,Drug-sensitivity results on antibiotics resistance showed that the total resistant rate was 87.65%. .The multiple antibiotics resistant rate was 69.14%.the highest resistant rates to ampicillin and carbenicillin were 88.89% and 85.19%,respectively.Next to ciprofloxacin,ofloxacin trimethoprim/sulfamethoxazole,and gentamicin were 56.79%,56.79%,54.32% and 45.68%,respectively.Next to cefazotin, cefotaxime, aztreonam and amikacin were 41.98%,29.63%,23.46% and 11.11%, respectively.The lowest resistant rates to ceftazidime cefepime nitrocefin and imipenem were 9.78%,11.11%9.88% and 0,respectively. There weren’t statistical differences between the UPEC strains and the non-UPEC strains in the antibiotics resistant rates. (P>0.05), but there were statistical differences between them in multiple antibiotics resistant rates. (P<0.01) And the UPEC linked with three and more than three kinds various virulence factor combinations all showed multiple antibiotics resistance.[Conclusion] l.papC gene was tested by PCR to select the UPEC strains.Suggested that these patients maybe suffered from Pyelonephritis.2.The positive rates of the four virulence factors in UPEC were all have statistical differences compared with non-UPEC.and these virulence maybe linked with each other.Suggestded that the virulence factors will enhance the pathogenicity of the UPEC. 3. Most of the Escherichia coli strains isolated from urine were antibiotic resistant..The multiple antibiotic resistant rates were higher than that of the non-UPEC. Indicated that the UPEC not only has higher pathogenicity,but also has seriously antibiotic resistance. Infection of the UPEC should cause the attention of the clinical.

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