Resistance And β-lactamase Detection Of Gram-negative Bacterium From Several Hospitals In Liuan

ObjectiveTo investigate the resistance of Gram-negative bacterium for guide rational use of antimicrobial agents.To investigate the distribution ofβ—lactamase genes in Gram-negative bacterium isolated from Liuan.Materials and MethodsTotally 102 non-repetitive Gram-negative bacterium were collected from three hospitals in September 2008 of LiuAn.M-H agar dilution method was used to determine MIC of 17 antimicrobial agents against wild-type isolates andβ—lactamase genes by polymerase chain reaction(PCR).The purified PCR products were ligated with pGEM-Teasy vectors,expressed in E.coli DH_5a,and sequenced by Sanger's dideoxy chain termination composition method,on an ABI377 automatic sequencer(Invotrigen, Shanghai,China).Then BLAST program was used to ascertain the genotype at GenBank.ResultsCarbapenems were the most effective antimicrobial agents against Gram-negative bacilli in the city,and the other effective ones were Piperacillin-tazobactam(73.5%), Amikacin(67.6%) and Fosfomycin(62.7%).Gram-negative bacilli showed very high resistance to Ampicillin(96.1%),Cefoxitin(83.3%),Aztreonam(81.4%). Sequence and BLAST results indicated that positive results for SHV-type were comprised of 6bla_SHV-12-carried strains,3bla_SHV-1-carried strains,positive results for TEM-type were all comprised of bla_TEM-1-carried strains,positive results for CTX-M-type were comprised of 5 bla_CTX-M-1-carried strains,6bla_CTX-M-9-carried strains.ConclusionThe resistance rate Gram-negative bacteria resistance to antimicrobial agents such as ampicillin,cefoxitin,cefuroxime,aztreonam,gentamicin is higher than 74.5%,in particular ampicillin,cefoxitin,second-generation cephalosporin cefuroxime and aztreonam.Bla_SHV-12,bla_OXA-10,bla_TEM-1,bla_CTX-M-9 were the mainly epidemic genotypes in our area, and had no evident difference between the novel enzymes and parent enzymes in resistance.