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首页> 外文期刊>International journal of medical microbiology: IJMM >Role of penA polymorphisms for penicillin susceptibility in Neisseria lactamica and Neisseria meningitidis
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Role of penA polymorphisms for penicillin susceptibility in Neisseria lactamica and Neisseria meningitidis

机译：penA基因多态性在乳酸奈瑟菌和脑膜炎奈瑟菌中对青霉素敏感性的作用

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摘要

In meningococci, reduced penicillin susceptibility is associated with five specific mutations in the transpeptidase region of penicillin binding protein 2 (PBP2). We showed that the same set of mutations was present in 64 of 123 Neisseria lactamica strains obtained from a carriage study (MIC range: 0.125-2.0 mg/L). The PBP2 encoding penA alleles in these strains were genetically similar to those found in intermediate resistant meningococci suggesting frequent interspecies genetic exchange. Fifty-six N. lactamica isolates with mostly lower penicillin MICs (range: 0.064-0.38 mg/L) exhibited only three of the five mutations. The corresponding penA alleles were unique to N. lactamica and formed a distinct genetic clade. PenA alleles with no mutations on the other hand were unique to meningococci. Under penicillin selective pressure, genetic transformation of N. lactamica penA alleles in meningococci was only possible for alleles encoding five mutations, but not for those encoding three mutations; the transfer resulted in MICs comparable to those of meningococci harboring penA alleles that encoded PBP2 with five mutations, but considerably lower than those of the corresponding N. lactamica donor strains. Due to a transformation barrier the complete N. lactamica penA could not be transformed into N. meningitidis. In summary, penicillin MICs in N. Iactamica were associated with the number of mutations in the transpeptidase region of PBP2. Evidence for interspecific genetic transfer was only observed for penA alleles associated with higher MICs, suggesting that alleles encoding only three mutations in the transpeptidase region are biologically not effective in N. meningitidis. Factors other than PBP2 seem to be responsible for the high levels of penicillin resistance in N. lactamica. A reduction of penicillin susceptibility in N. meningitidis by horizontal gene transfer from N. lactamica is unlikely to happen. (C) 2015 Elsevier GmbH. All rights reserved.
机译：在脑膜炎球菌中，青霉素敏感性降低与青霉素结合蛋白2（PBP2）的转肽酶区域中的五个特定突变有关。我们显示，通过运输研究获得的123株乳酸奈瑟氏球菌中有64株存在相同的突变（MIC范围：0.125-2.0 mg / L）。这些菌株中编码PBP2的penA等位基因在遗传上与在中等抗性脑膜炎球菌中发现的基因相似，表明频繁的种间遗传交换。五十六种乳酸青霉菌菌株中青霉素MIC含量较低（范围：0.064-0.38 mg / L），仅显示五个突变中的三个。相应的penA等位基因是乳酸奈瑟球菌特有的，并形成了独特的遗传进化枝。另一方面，没有突变的PenA等位基因是脑膜炎球菌所特有的。在青霉素选择压力下，脑膜炎球菌中乳酸奈瑟氏球菌penA等位基因的遗传转化仅对编码五个突变的等位基因是可能的，而对编码三个突变的那些等位基因则不可能。转移导致的MIC与携带编码5个突变的PBP2的penA等位基因的脑膜炎球菌相当，但比相应的内乳酸奈瑟氏菌供体株低。由于转化障碍，不能将完整的内酰胺酶penA转化为脑膜炎奈瑟氏球菌。总之，I.amicamica中的青霉素MIC与PBP2的转肽酶区域中的突变数有关。种间遗传转移的证据仅在与较高MIC相关的penA等位基因中观察到，这表明在转肽酶区域中仅编码三个突变的等位基因在脑膜炎奈瑟氏球菌中生物学无效。 PBP2以外的其他因素似乎是造成乳酸奈瑟菌中青霉素耐药性高的原因。通过从乳酸奈瑟菌中水平转移基因来减少脑膜炎奈瑟菌中青霉素敏感性的可能性不大。 （C）2015 Elsevier GmbH。版权所有。

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