[Resistance by hypermutable Pseudomonas aeruginosa and beta-lactamases production].
OBJECTIVE
To determine the relation between resistance of hypermutable Pseudomonas aeruginosa and beta-lactamases produced.


METHODS
The bacteria cultured were identified with API 20NE system. Susceptibilities of the bacteria were detected by disk diffusion method. The hypermutable strains were tested with broth dilution assays. The beta-lactamases produced by these strains were characterized by 3-dimensional test and 2-mercaptopropanoic acid inhibited assays.


RESULTS
Altogether 120 strains were analyzed and 45 (37.5%) trains were hypermutable.The resistant rates of hypermutable strains were close to or above 60.0% for imipenem, meropenem, cefoperazone/sulbactam, piperacillin/ tazobactam, ceftazidime, cephfime, aztreonam, amikacin and ciprofloxacin.The 3-dimensional test showed that 18 (40.0%) strains produced extended spectrum beta-lactamases (ESBLs), 25 (55.6%) strains produced AmpC enzymes, and 6 (13.3%) strains produced metallo-beta-lactamases.


CONCLUSIONS
The resistant rates of hypermutablce strains of Pseudomonas aeruginosa to routine antibiotics are high, which is one of the most important reasons for multi-drug resistance that the hypermutable strains produced ESBLs, AmpC enzymes, and metallo-beta-lactamases.
Cao
Wei
W
Department of Clinical Laboratory,Second Xiangya Hospital,Central South University, Changsha 410011, China. cwcao10741@sohu.com
Yao
Dongmei
D
Zheng
Rong
R
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D029481:Bronchitis, Chronic / Q000382:microbiology; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009154:Mutation; D011550:Pseudomonas aeruginosa / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics*; D011660:Pulmonary Heart Disease / Q000382:microbiology; D001618:beta-Lactamases / Q000096:biosynthesis*
D001618:beta-Lactamases