Saika T, Hasegawa M, Kobayashi I, Nishida M
Chemotherapy Division, Mitsubishi Kagaku Bio Clinical Laboratories, Inc.
Kansenshogaku Zasshi. 1998 Feb;72(2):97-104. doi: 10.11150/kansenshogakuzasshi1970.72.97.
The clinical isolates of Pseudomonas aeruginosa can be roughly classified into long- and short-lipopolysaccharide (LPS) strains and LPS-deficient strains, based on the silver-stained patterns of their LPSs after SDS-PAGE. The ionic binding of 3H-gentamicin, a polycationic antibiotic, to the negatively charged sites on the surface structures of P. aeruginosa strains, often differing in LPS structure, was the highest in the long-LPS strains followed in descending order by the short-LPS strains and LPS-deficient strains. It was presumed that a clinical isolate of P. aeruginosa No. 45 is lacking in the O-polysaccharide chains and some structures of the core-regions consisting of its LPS-structure after SDS-PAGE. On the other hand, the binding of 3H-gentamicin to this strain was quite. high, i.e., similar to that to of the long-LPS strains. To clarify this finding, P. aeruginosa PAC1R and its LPS-deficient mutants were used as reference strains because the chemical structures of their LPSs containing the repeated units of O-polysaccharides and the neutral sugar contents in the core-regions were previously confirmed. The PAC605 strain of the LPS-mutants of the PAC series, was completely lacking in the repeated units of O-polysaccharide and also lacking in some neutral sugar residues of the core-oligosaccharide region. However, this strain was highly bound to 3H-gentamicin, suggesting that the negatively charged sites on the deep core-oligosaccharide region and/or on lipid A participated in the binding of 3H-gentamicin. This manner of binding may be also applied to P. aeruginosa No. 45. When P. aeruginosa PAC1R, PAC605 and No. 45 strains were each exposed to gentamicin (20 micrograms/ml) for 10 minutes, the viable cell counts of PAC1R decreased to about 70% of the initial count, whereas the viable cell counts of PAC605 and No. 45 strains decreased to 3.6 and 11.0% respectively, indicating the vulnerability of both types of the strains to be enhanced by the bactericidal action of gentamicin with short-term incubation.
基于铜绿假单胞菌临床分离株脂多糖（LPS）在SDS-PAGE后银染的模式，可大致将其分为长型和短型LPS菌株以及LPS缺陷型菌株。多阳离子抗生素3H-庆大霉素与LPS结构常不同的铜绿假单胞菌菌株表面结构上带负电荷位点的离子结合，在长型LPS菌株中最高，其次是短型LPS菌株和LPS缺陷型菌株，呈递减顺序。据推测，铜绿假单胞菌45号临床分离株在SDS-PAGE后缺乏O-多糖链及其LPS结构中由核心区域组成的一些结构。另一方面，3H-庆大霉素与该菌株的结合相当高，即与长型LPS菌株的结合相似。为阐明这一发现，使用铜绿假单胞菌PAC1R及其LPS缺陷型突变体作为参考菌株，因为它们含O-多糖重复单元的LPS化学结构以及核心区域的中性糖含量先前已得到确认。PAC系列LPS突变体的PAC605菌株完全缺乏O-多糖重复单元，并且也缺乏核心寡糖区域的一些中性糖残基。然而，该菌株与3H-庆大霉素高度结合，表明核心寡糖区域深处和/或脂质A上带负电荷的位点参与了3H-庆大霉素的结合。这种结合方式可能也适用于铜绿假单胞菌45号菌株。当铜绿假单胞菌PAC1R、PAC605和45号菌株分别暴露于庆大霉素（20微克/毫升）10分钟时，PAC1R的活菌数降至初始数的约70%，而PAC605和45号菌株的活菌数分别降至3.6%和11.0%，表明短期孵育时庆大霉素的杀菌作用增强了这两种菌株的易感性。
