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Epidemiological and genetical analyses of clinical isolates resistant to newly developed antimicrobials

对新开发的抗菌药物耐药的临床分离株的流行病学和遗传学分析

基本信息

批准号：
61480142
负责人：
HASHIMOTO Hajime
金额：
$ 3.71万
依托单位：
Gunma University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1986
资助国家：
日本
起止时间：
1986 至 1988
项目状态：
已结题

项目摘要

We examined 385 clinical isolates of P.aeruginosa and selected 90 strains resistant to at least one of 23 antibacterials tested. Using these strains, we determined their serum type, phage type and plasmid type and analysed their relationship with their drug-resistances. There found greatest differences between drug-resistant and sensitive strains in the case of gentamicin. GM-resistant strains belonged mostly to serum type I or nontypable. All of the GM-resistant isolates from different origin isolated in 1984 expressed the same multiple resistance, were grouped to serum type I and phage nontypable, and possessed nonconjugative miniplasmid encoding the multiple resistance. The same type strains have been isolated sporadically since 1985. Conjugally transmissible GM-resistant isolates showing different multiple resistance were found since 1985 and most of them were serum-nontypable. Thus we suspect the nosocomial infection in our hospital.Developement of drug-resistance owing to the abundant use of antimicrobials was demonstrated in the increase of norfloxacin-resistant P.aeruginosa accompanied with the increased use of new quinolone antimicrobials. The drug-sensitive clinical isolates were able to mutate to higher level of quinolone resistance with or without accompanying the change of sensitivities to other drugs. Mutants expressing the change of sensitivity to 2 or more kind of antimicrobials showed various changes in their outer-membrane proteins, resulting in the change of drug-permeability.

我们检测了385株铜绿假单胞菌临床分离株，并选择了90株对23种抗菌药物中至少一种耐药的菌株。对分离菌株进行血清型、噬菌体型和质粒型测定，并分析其与耐药性的关系。在庆大霉素的情况下，发现耐药菌株和敏感菌株之间的差异最大。GM耐药株多为血清I型或非分型株。1984年分离的不同来源的GM耐药菌株均表现出相同的多重耐药，并被归为血清I型和噬菌体不可分型，且具有编码多重耐药的非接合性小质粒。自1985年以来，已零星分离到相同类型的菌株。自1985年以来，发现了具有不同多重抗性的接合传播GM抗性分离株，其中大多数是血清不可分型的。由于抗菌药物的大量使用，铜绿假单胞菌对去甲氧西林的耐药性增加，同时新型喹诺酮类抗菌药物的使用也在增加。临床分离株对喹诺酮类药物的敏感性可发生突变，对其他药物的敏感性也可发生变化。对2种或2种以上抗菌药物敏感性改变的突变株，其外膜蛋白发生了不同程度的变化，从而导致药物通透性的改变。