ABSTRACT
OBJECTIVE To investigate the drug-resistance of Enterobacter cloacae(ECL) and its carrying rate of gene encoding aminoglycosides modifying enzymes(AMEs).METHODS Totally 132 clinically isolated ECL strains were identified with VITEK-32.Their drug susceptibility was tested with K-B disc diffusion.The presence of ESBLs and AmpC was tested with three dimensional test.The genes encoding AMEs were detected with PCR and confirmed by sequence.RESULTS All strains of ECL were susceptible to IMP and MER.The resistance rate to AMK,LVX,FEP,CFS and CIP was 21.2%,35.6%,37.9%,46.2% and 48.5%,respectively with gradually increasing.Their resistance rate to other antibiotics ranged from 50.0% to 87.7%.Among 132 strains of ECL,45 strains producing ESBLs,accounted for 34.1%,27 strains producing AmpC,accounted for 20.5%,11 strains producing ESBLs and AmpC,accounted for 8.3% and 49 strains producing neither ESBLs nor AmpC,accounted for 37.1%.Seven strains without positive detection of ESBLs were resistant to CTX and CAZ,but carried the genes of resistance to TEM and SHV.The detection rate of genes encoding AMEs was about 62.1%,among which subtypes of aac(6′)-Ⅰb dominated with detection rate of 51.5%.Meanwhile the detection rate of subtype aac(3)-Ⅰ,aac(3)-Ⅱ,aac(6′)-Ⅱ,ant(3″)-Ⅰ,ant(2″)-Ⅰ and aph(3′)-Ⅵ was 15.9%,12.9%,18.9%,37.1%,6.8% and 9.8%,respectively.The detection rate of carrying more than two types of AMEs was about 89.0%.There were 5 strains of presenting phenotypic resistance without detection of genes encoding AMEs.CONCLUSIONS The clinically isolated ECL strains are not only severe resistant to drug and but also multi-drug resistant.The carrying rate of genes encoding ESBLs,AmpC and AMEs is higher than estimated which is the leading cause of resistance to antibiotics.
ABSTRACT
OBJECTIVE To study the aminoglycosides modifying enzyme genes and intⅠ gene in Stenotrophomonas maltophilia in Chinese Armed Police Forces General Hospital.METHODS The samples of 27 multi-resistant S.maltophilia were collected from inpatiens from Jan 2006 to Oct 2007 in this Hospital.The sensitivity of the isolates to 14 antibacterial agents was determined using a broth induction method.The aminoglycosides modifying enzyme genes and intⅠ 1 gene were detected by PCR.RESULTS The multi-drug resistance of S.maltophilia was a serious problem.In 27 strains of S.maltophilia,the positive ant(2″)-Ⅰ were in 5 strains(18.5%),aac(3)-Ⅱ in 3 strains(11.1%)and aac(6')-Ⅱ in 1 strain(3.7%).The positive intⅠ gene was found in 11 strains(29.6%).CONCLUSIONS Multi-resistant S.maltophilia resistant to aminoglycosides mainly due to the presence of aminoglycoside modifying enzymes ant(2″)-Ⅰ,aac(3)-Ⅱ and aac(6')-Ⅱ.The aminoglycoside modifying enzymes ant(3″)-Ⅰ and aac(6)-ⅠZ were not detected carrying IntⅠ would be the reason of S.maltophilia resistant to aminoglycosides.
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OBJECTIVE To study the aminoglycosides modifying enzyme genes and detect resistance of the Acinetobacter baumannii in burn unit.METHODS The susceptibility of the A.baumannii strains to 11 antibiotics were tested by K-B method.The aminoglycosides modifying enzyme genes were analyzed using polymerase chain reaction(PCR).RESULTS The resistance rate to antibacterials was as follows:to TZP 61.85%,SCF 23.69%,CAZ 64.48%,FEP 63.17%,IPM 63.17%,AK 56.58%,and to CIP 73.69%.In 76 strains of A.baumannii,48 strains(63.16%) were with aac(3)-Ⅰ,39(51.32%) with aac(6′)-Ⅰ,and 46(60.53%) with ant(3″)-Ⅰ,others were negative.The total test rate of aminoglycosides modifying enzyme gene was 63.16%.CONCLUSIONS There are not only multi-drug-resistance but also 63.16% aminoglycosides modifying enzyme genes of the A.baumannii isolated from burn unit.
ABSTRACT
Objective To study the mechanism of resistance to antibiotics and disinfectants of Pseudomonas aeruginosa isolated from clinical specimens in a hospital, and to provide a reference for the use of aminoglycoside antibiotics for the treatment of P. aeruginosa infection as well as disinfection and sterilization. Methods 35 strains of multi-resistant P. aeruginosa were screened from clinical specimens by susceptibility test of agar dilution. Five kinds of aminoglycoside modifying enzyme gene and qzcE?1 gene were detected by polymerase chain reaction (PCR) method. Results The positive rates of aminoglycoside modifying enzyme genes, including aac(3)-Ⅱ, aac(6′)-Ⅰ, aac(6′)-Ⅱ, ant(3″)-Ⅰ and ant(2″)-Ⅰ, were 48.6%, 40%, 54.3%, 45.7% and 60%, respectively, and nearly all strains were positive for 2 or more than 2 kinds of above aminoglycoside modifying enzyme gene. The positive rate of qzcE?1 gene was 94.3%. Conclusions There was a close relationship between aminoglycoside modifying enzyme producing P. aeruginosa and its multi-resistance to antibiotics, The results suugested that aminoglycosides should be used cautiously, and it should be based on the result of susceptibility test in the treatment of P. aeruginosa infection, and it was inadvisable to use quaternary ammonium and biguanides disinfectant in disinfection and sterilization.
