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目的 探讨淋病奈瑟菌（ ＮＧ）Ｌ 型的耐药性与其质粒的关系。方法 将２ 株产青霉素酶淋病奈瑟菌（ ＰＰＮＧ） 诱导成Ｌ 型，并传代。测定每代菌中的质粒携带情况、β内酰胺酶活性及对四种抗生素的敏感性。结果 传至第７ 代时，２ 株ＮＧ 编码β内酰胺酶的质粒丢失，Ｌ 型的β内酰胺酶活性转阴，它们的回复菌对青霉素的最小抑菌浓度（ ＭＩＣ） 比原菌大大降低，分别从８ ｍ ｇ／Ｌ 和１６ ｍ ｇ／ Ｌ 降低到１ ｍ ｇ／Ｌ 和０ ．２５ ｍｇ／Ｌ，在传至１０ ～１５ 代时，４ ．２ｋｂ 隐蔽质粒也丢失，这使得ＮＧ 失去一个重要的特征性标志。稳定的ＮＧＬ 型对青霉素的 ＭＩＣ 高达６４ ｍ ｇ／Ｌ 以上。ＮＧ 质粒的丢失与其对四环素、壮观霉素及头孢三嗪的耐药性无明显关系。结论 ＮＧ对青霉素的耐药性既与质粒有关且与细胞壁是否缺陷关系更大。
Objective To investigate the relationship between drug resistance of Neisseria gonorrhoeae and its plasmid. Methods Two strains of Neisseria gonorrhoeae producing penicillinase (PPNG) were induced into Ltype and passaged. Determination of the plasmid carrying each generation of bacteria, lactamase activity and the four antibiotics sensitivity. The results passed to the 7th generation, two NG encoding β lactamase plasmid was lost, L-type β lactamase activity turned negative, their response to penicillin, the minimum inhibitory concentration (MIC) than the original bacteria Greatly reduced, from 8 m g / L and 16 m g / L to 1 m g / L and 0, respectively. 25 mg / L, in the spread of 10 to 15 generations, 4. 2kb concealed plasmid is also lost, which makes NG lost an important characteristic signs. Stable NG L type of penicillin MIC up to 64 m g / L or more. There was no significant relationship between the loss of NG plasmid and its resistance to tetracycline, spectinomycin and ceftriaxone. Conclusion The resistance of NG to penicillin is not only related to plasmids but also to the cell wall defects.