Søgaard P, Togsverd E, Mansa B
Department of Clinical Microbiology, Odense University Hospital, Denmark.
Acta Pathol Microbiol Immunol Scand B. 1987 Oct;95(5):297-302. doi: 10.1111/j.1699-0463.1987.tb03128.x.
A collection of Enterobacter cloacae strains from Odense University Hospital from 1977 were compared with a collection from 1985 as regards acquired resistance traits. Among the strains with carbenicillin (Ca) resistance, the number of multiresistant strains decreased while the number with sole Ca-resistance increased. In 1977, a high proportion of the Ca-resistant (Ca-r) strains had plasmid-mediated beta-lactam resistance, but in 1985 the Ca-r strains were completely dominated by organisms with elevated amounts of chromosomally-mediated beta-lactamase. The latter, but not the former, strains were resistant to the newer cephalosporins (e.g. cefotaxime (Ctax)). The consumption of Ctax and cefuroxime increased from 0 kg in 1977 to 7.0 kg in 1985. It is therefore probable that this increase was the cause of the change in occurrence of the resistance types. Ninety-one % of the Ca-r strains were isolated from urinary samples in 1977. The percentage was only 31 in 1985. This change, concomitant with the increase in Ctax-r strains, can probably be explained by the better conditions for selection of Ctax-r mutants, producing greater amounts of chromosomal beta-lactamase, in wounds and respiratory tract than in urine.
对1977年从欧登塞大学医院收集的阴沟肠杆菌菌株与1985年收集的菌株进行了获得性耐药性状方面的比较。在耐羧苄青霉素（Ca）的菌株中，多重耐药菌株的数量减少，而仅耐Ca的菌株数量增加。1977年，高比例的耐Ca（Ca-r）菌株具有质粒介导的β-内酰胺耐药性，但在1985年，Ca-r菌株完全由染色体介导的β-内酰胺酶量增加的菌株主导。后一种菌株（而非前一种）对新型头孢菌素（如头孢噻肟（Ctax））耐药。头孢噻肟和头孢呋辛的消耗量从1977年的0千克增加到1985年的7.0千克。因此，这种增加很可能是耐药类型出现变化的原因。1977年，91%的Ca-r菌株从尿液样本中分离得到。1985年这一比例仅为31%。这种变化与Ctax-r菌株的增加同时出现，可能是因为与尿液相比，伤口和呼吸道更有利于选择产生更多染色体β-内酰胺酶的Ctax-r突变体。
