人們都知道，消毒劑使用時間長了,，細(xì)菌就會產(chǎn)生一定抵抗力,，必須用更高濃度的消毒劑才能達(dá)到抑菌或殺菌目的。而愛爾蘭研究人員最新研究發(fā)現(xiàn),，消毒劑還會“訓(xùn)練”細(xì)菌,，使其對抗生素藥物也產(chǎn)生耐藥性，從而形成“超級病菌”,。
國立愛爾蘭大學(xué)研究人員在新一期英國《微生物學(xué)》雜志上報(bào)告說,，他們在實(shí)驗(yàn)過程中向綠膿桿菌的培養(yǎng)液中添加消毒劑，并且不斷增加消毒劑的用量,。結(jié)果發(fā)現(xiàn),，這種細(xì)菌會努力適應(yīng)消毒劑并在這種“敵我斗爭”中存活下去。
讓研究人員意想不到的是,，當(dāng)他們把對消毒劑產(chǎn)生抵抗力的綠膿桿菌置于臨床常用抗生素“環(huán)丙沙星”環(huán)境中時,，綠膿桿菌竟然有了耐藥性。也就是說,，在之前未接觸過抗生素的情況下,，綠膿桿菌在消毒劑的“訓(xùn)練”下就可以產(chǎn)生耐藥性。
研究人員介紹說,，細(xì)菌本身可以不斷適應(yīng)有消毒劑的環(huán)境,，變得能更有效地把細(xì)菌細(xì)胞內(nèi)的抗菌物質(zhì)排出。這時細(xì)菌的遺傳物質(zhì)DNA（脫氧核糖核酸）已經(jīng)發(fā)生了一定改變,，使其對某種抗生素產(chǎn)生特定耐藥性,。
綠膿桿菌是常見的一種致病菌，那些自身免疫系統(tǒng)弱或患有免疫系統(tǒng)疾病的人容易感染這一細(xì)菌,，它也是醫(yī)院內(nèi)重要的細(xì)菌感染類型之一,。因此，醫(yī)院常使用消毒劑擦拭室內(nèi)以及醫(yī)療器械等各處的表面,，以防綠膿桿菌感染,。
研究人員說，他們的研究結(jié)果對于研究如何更加有效地控制醫(yī)院內(nèi)細(xì)菌感染非常重要,，而且也有助于進(jìn)一步理解細(xì)菌產(chǎn)生耐藥性的環(huán)境影響因素。（生物谷Bioon.com）
生物谷推薦原始出處：
Microbiology 156 (2010), 30-38; DOI 10.1099/mic.0.029751-0
Effect of subinhibitory concentrations of benzalkonium chloride on the competitiveness of Pseudomonas aeruginosa grown in continuous culture
Paul H. Mc Cay, Alain A. Ocampo-Sosa and Gerard T. A. Fleming
Department of Microbiology, School of Natural Sciences, National University of Ireland, Galway, Ireland
This study investigates the link between adaptation to biocides and antibiotics in Pseudomonas aeruginosa. An enrichment continuous culture of P. aeruginosa NCIMB 10421 (MIC 25 mg BKC l–1) was operated (D=0.04 h–1, 792 h) with added benzalkonium chloride (BKC). A derivative, PA-29 (696 h), demonstrated a >12-fold decrease in sensitivity to the biocide (MIC >350 mg BKC l–1). The variant demonstrated a 256-fold increase in resistance to ciprofloxacin, with a mutation in the gyrA gene (Thr-83Ile). Similarly, culturing of the original strain in a continuous-culture system with ciprofloxacin selection pressure led to the evolution of BKC-adapted populations (MIC 100 mg BKC l–1). Efflux pump activity predominantly contributed to the developed phenotype of PA-29. An amino acid substitution (Val-51Ala) in nfxB, the Mex efflux system regulator gene, was observed for PA-29. Overexpression of both MexAB-OprM and MexCD-OprJ was recorded for PA-29. Similarly, mexR, a repressor of the Mex system, was downregulated. Competition studies were carried out in continuous culture between PA-29 and the original strain (in the presence of subinhibitory concentrations of BKC). The outcome of competition was influenced by the concentration of biocide used and the nature of limiting nutrient. The inclusion of 1 mg BKC l–1 in the medium feed was sufficient to select (S=0.011) for the BKC-adapted strain in magnesium-limited culture. Conversely, the presence of 10 mg BKC l–1 in the medium supply was insufficient to select for the same organism (S=–0.017) in the glucose-limited culture. These results indicate the importance of environmental conditions on selection and maintenance of biocide adaptation.
