Plasmid analysis of Neisseria gonorrhoeae isolates and dissemination of tetM genes in southern Africa 1993-1995.
Plasmid analysis of Neisseria gonorrhoeae isolates and dissemination of tetM genes in southern Africa 1993-1995.
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1993-1995 年南部非洲淋病奈瑟氏菌分离株的质粒分析和 tetM 基因的传播。
DOI：
10.1093/jac/40.6.817
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发表时间：
1997
影响因子：
5.2
通讯作者：
P. Botha
中科院分区：
文献类型：
--
作者：
L. Chalkley;M. N. Janse van Rensburg;P. Matthée;C. Ison;P. Botha
一组（145株）淋病奈瑟菌收集自1994年布隆方丹市诊所，第二组（65株）于1995年。确定青霉素和四环素MIC，并进行质粒分析，以监测这些分离株中质粒的发生情况以及抗菌药物的敏感性。在研究期间，由β-内酰胺酶质粒引起的青霉素耐药率保持在9%不变。1994年，在南非首次发现了三种高水平的四环素耐药菌株（MIC 16 mg/L）。尽管携带24.5 MDa接合性质粒的分离株的百分比有所减少（从1994年的79%减少到1995年的46%），但TetM编码接合性质粒（25.2 MDa）从2%增加到18.5%部分抵消了这一点。13株四环素耐药菌株的tetM基因均为美洲型。在11株分离株中发现美洲型四环素耐药质粒。用Bg/l消化显示，两个分离株含有与先前描述的美国和荷兰型质粒不同的tetM编码质粒：一个分离株含有产生与美国型质粒不同大小的两个片段的质粒，第二个分离株具有美国/荷兰杂交质粒。PCR分型/血清分型和随机扩增多态性DNA分析揭示了一个主要的四环素耐药家族（NR/IA-6，基因组I）在布隆方丹。由于南部非洲衣原体感染的发病率很高，需要四环素治疗，因此环境中存在维持和快速传播高水平四环素耐药N.淋病tetM基因可能是从博茨瓦纳和/或纳米比亚传播到布隆方丹的。高水平四环素抗性N.在布隆方丹的淋病被认为是复杂的，因为鉴定了一组相关的菌株，质粒传播是明显的，并且证明了两种新的TetM编码质粒。这些TetM编码质粒的出现表明美国和荷兰型质粒正在继续进化，或者tetM基因正在被引入不同的24.5 MDa接合质粒家族。
One group (145 isolates) of Neisseria gonorrhoeae was collected from municipal clinics in Bloemfontein in 1994 and a second group (65 isolates) in 1995. Penicillin and tetracycline MICs were determined and plasmid analysis performed to monitor antimicrobial susceptibilities in conjunction with the occurrence of plasmids in these isolates. The prevalence of penicillin resistance caused by beta-lactamase plasmids remained constant at 9% during the study period. Three high-level tetracycline-resistant strains (MICs 16 mg/L), the first to be detected in South Africa, were isolated in 1994. Although there was a reduction in the percentage of isolates harbouring 24.5 MDa conjugative plasmids (from 79% in 1994 to 46% in 1995), this was partially counteracted by an increase in TetM-encoding conjugative plasmids (25.2 MDa) from 2% to 18.5%. The tetM genes of 13 isolates shown to exhibit high-level tetracycline resistance were characterized as the American type. The American-type tetracycline resistance plasmid was demonstrated in 11 isolates. Digestion with Bg/l showed that two isolates harboured tetM-encoding plasmids that differed from the American- and Dutch-type plasmids described previously: one isolate contained a plasmid that produced two fragments of different sizes from those of the American-type plasmid and the second isolate possessed an American/Dutch hybrid plasmid. Auxotyping/serotyping and random amplified polymorphic DNA analysis revealed a predominant tetracycline-resistant family (NR/IA-6, genomic group I) in Bloemfontein. As there is a high incidence of chlamydial infections in southern Africa requiring tetracycline therapy, selective pressures exist in the environment for the maintenance and rapid spread of high-level tetracycline-resistant N. gonorrhoeae. It is possible that tetM genes may have emanated from Botswana and/or Namibia to Bloemfontein. The establishment of high-level tetracycline-resistant N. gonorrhoeae in Bloemfontein was seen to be complex as a related group of strains was identified, plasmid dissemination was evident and two new TetM-encoding plasmids were demonstrated. The appearance of these TetM-encoding plasmids indicates either that the American- and Dutch-type plasmids are continuing to evolve or that tetM genes are being introduced into different families of 24.5 MDa conjugative plasmids.