Tavío Pérez M M, Amicosante G, Franceschini N, Vila J, Ruiz J, Oratore A, Martín-Sánchez A M, Jiménez de Anta M T
Department of Clinical Sciences, School of Medicine, University of Las Palmas de G.C., Spain.
Microb Drug Resist. 1999 Winter;5(4):235-40. doi: 10.1089/mdr.1999.5.235.
The effect of fluoroquinolones in Citrobacter freundii strains that results in a decreased expression of cephalosporin-hydrolysing beta-lactamases was studied. Resistance to broad-spectrum cephalosporins and penicillins in two C. freundii clinical isolates was associated with moderate production of chromosomal AmpC-type-beta-lactamase in addition to changes in the outer membrane proteins profile with respect to wild-type C. freundii strains. Ten quinolone-resistant mutants were derived from the two clinical isolates using increasing fluoroquinolone concentrations. The level of susceptibility to cephalosporins and meropenem of these 10 mutants was increased and was associated with a 3.6-32% diminution in the hydrolyzing activity of their periplasmic extracts containing beta-lactamases on cephaloridine as compared with those from their parent strains. Susceptibility to cephalosporins and meropenem, as well as the expression of chromosomal AmpC-type-beta-lactamase in C. freundii strains, was influenced by the exposure to quinolones.
研究了氟喹诺酮类药物对弗氏柠檬酸杆菌菌株的影响，该影响导致头孢菌素水解β-内酰胺酶的表达降低。两株弗氏柠檬酸杆菌临床分离株对广谱头孢菌素和青霉素的耐药性，除了外膜蛋白谱相对于野生型弗氏柠檬酸杆菌菌株发生变化外，还与染色体AmpC型β-内酰胺酶的中度产生有关。使用逐渐增加的氟喹诺酮浓度从这两株临床分离株中获得了10个喹诺酮耐药突变体。这10个突变体对头孢菌素和美罗培南的敏感性水平有所提高，并且与它们含有β-内酰胺酶的周质提取物对头孢菌素的水解活性相比其亲本菌株降低了3.6%-32%有关。弗氏柠檬酸杆菌菌株对头孢菌素和美罗培南的敏感性以及染色体AmpC型β-内酰胺酶的表达受到喹诺酮类药物暴露的影响。
