| Objective: 1. To comprehend the clinical distribution and drug resistance of E. cloacae isolated from Jan 2008 to Dec 2014 so as to provide basis for the clinical reasonable use of antibiotics. 2. To detect phenotypes of extented spectrun beta-lactamases and Amp C beta-lactamases and plasmid-mediated drug resistance genes for preliminary study on the mechanisms of E.cloacae in our hospital. 3. To analyse the molecular epidemiological characteristics of drug resistant isolates of E. cloacae,so as to provide basis for control spreading of resistant isolates in the hospital. Methods: 1. The clinical data of drug resistance of our hospital on all of E. cloacae isolates during seven years were analyzed retrospectively by using WHONET5.6 software. 2. A total of 174 non-repetitive E. cloacae were isolated from June 2013 to June 2014 in the Affiliated Hospital of Guiyang Medical College for the following tests: ①The different phenotypes of extented spectrun beta-lactamases and Amp C beta-lactamases were detected by Multi-Substrates Synergy-Antagonize Test(MSSAT). ②PCR was used to detect plasmid-mediated extented spectrun beta-lactamase genes(TEM-1、SHV-12、CTX-M-3、SFO-1、VEB-3), Amp C beta-lactamase genes(ACT-1、DHA-1)and quinolone resistance genes(qnr A、qnr B、qnr S). ③ERIC was used to compare the similarity of the isolates of resistance genes in E.cloacae. Results: 1. Drug resistance analysis results showed that detection rate of the secretion was highest among main specimen. A total of 1596 clinical strains of E. cloacae were isolated during seven years, which mainly isolated from respiratory tract specimens, secretions, urine. Drug resistance rate of the urine was the highest. The clinical distribution of E.cloacae strains mainly isolated from surgery, internal medicine, intensive care unit(ICU). Drug resistance rate in ICU was the highest. In age groups,most infected objects were adults and elderly patients. Adults was the highest in the rates of drug-resistant and children was the lowest. In six years, the percentage of E. cloacae resistant to piperacillin was the highest(44.0%~69.0%), which showed the lowest resistant rate to imipenem(<8.0%). The drug resistance rates of E.cloacae have decreased from 2009 to 2013(P<0.05), except for ceftriaxone, imipenem, trimethoprim/sulfamethoxazole, ticarcillin/clavulanic acid, piperacillin/tazobactam. 2.MSSAT results showed that there were 92(52.87%)strains were identified as only Amp C beta-lactamases producing, 1(0.57%)strains was identified as only extented spectrun beta-lactamase producing, 54(31.03%) strains were identified as both producing Amp C beta-lactamases and extented spectrun beta-lactamases, 27(15.52%) strains were identified as non-beta-lactamase producing in 174 E.cloacae strains. Drug resistance rate of beta-lactamases producing strains was significantly higher than non-beta-lactamase producing strains in E.cloacae(P<0.05). Drug resistance rate of both Amp C beta-lactamases and ESBLs producing strains was significantly higher than only Amp C beta-lactamase producing strains(P<0.05). The percentage of E.cloacae which producing both Amp C and ESBLs β-lactamases resistant to ceftriaxone was 98.1 %, to cefotaxime was 96.3%, to piperacillin was 92.5%, to aztreonam was 88.9%, to amikacin was relatively low(15.1%), to imipenem was sensitive.3.PCR results showed that there were 71 strains contained plasmid-mediated β-lactamase genes in 174 E.cloacae strains. The positive rate of ESBLs gene was 31.03%(54/174), which found 43 strains contained TEM-1genes, 22 strains contained SHV-12 genes, 21 strains contained CTX-M-3 genes, 12 strains contained SFO-1 genes, 1 strain contained VEB-3 gene.The positive rate of Amp C β-lactamase gene was 21.26%(37/174), which found 22 strain contained DHA-1 genes, 17 strains contained ACT-1. In 71 containing β-lactamases genes strains, there were 30 strains contained only one kind of β-lactamases genes, the other 41 strains contained two or more than two kinds of β-lactamases genes. The positive rate of quinolone resistance genes was 27.01%(47/174).16 strains were positive for qnr A gene, 25 strains were positive for qnr B gene and 15 strains were positive for qnr S gene. There were 9 strains contained two kinds of quinolone resistance genes. ESBLs and(or)Amp Cgenes positive strains were more easier carried qnr genes than genes negative strains(P<0.05). 4. ERIC showed that 24 genotypes among 70 E. cloacae strains with drug resistance genes positive. The main patterns were as followed: pattern X(18 strains), pattern V(9 strains), pattern W(6 strains). Conclusion: 1. The changes of resistance rates of E. cloacae to antimicrobials were decreased. The emergence of carbapenems-resistant of E.cloacae should be paid more attention. 2. E.cloacae mainly produced Amp C β-lactamases. Both Amp Cs and ESBLs produceing of E.cloacae showed high drug resistance to third generation cephalosporin, single ring antibiotics and penicillin, which showed sensitive to carbapenem antibiotics. Carbapenem antibiotics is still the first choice for treatment of multiple drug-resistant with E.cloacae infection. 3.E.cloacae contained different types of β-lactamase and qnr genes. ESBLs genes is given priority to with TEM-1 type gene. ESBLs and(or) Amp C genes positive strains can carry QNR genes at the same time. 4.There were scattered transmission among E. cloacae with resistance gene the hospital environments. |
PDF Full Text Request