Granier Sophie A, Leflon-Guibout Véronique, Goldstein Fred W, Nicolas-Chanoine Marie-Hélène
Service de Microbiologie-Hygiène, Hôpital Ambroise Paré, Boulogne-Billancourt, Paris, France.
Antimicrob Agents Chemother. 2003 Sep;47(9):2922-8. doi: 10.1128/AAC.47.9.2922-2928.2003.
The two genetic groups (oxy-1 and oxy-2) previously identified in the Klebsiella oxytoca taxon are recognizable by four independent molecular markers: (i). ERIC-1R profiles, (ii). 16S ribosomal DNA (rDNA) signature sequences, (iii). singular nucleotides in a defined fragment of the rpoB gene, and (iv) the type of the strain's bla(OXY) gene (i.e., bla(OXY-1) or bla(OXY-2)). K. oxytoca strains SG266 and SG271 could not be classified into these genetic groups based on their ERIC-1R profile and bla(OXY) gene sequence. With regard to the gene identity percentages between the bla(OXY-1) and bla(OXY-2) gene groups (86.8% +/- 0.4%) and within a bla(OXY) gene group (>99%), it was concluded that the bla(OXY) gene of strain SG271 was representative of a new bla(OXY) gene group (bla(OXY-3)), since the mean identity percentages between it and the two bla(OXY) gene groups were 85.5% +/- 0.2% and 84.4% +/- 0.4%, respectively. Since the corresponding percentages were 95.0% +/- 0.4% and 86.2% +/- 0.3% for strain SG266, it was impossible to classify its bla(OXY) gene, which was therefore named bla(OXY-4). The 16S rDNA signature sequences of the two strains could be determined only after cloning experiments. The SG266 clones displayed the same signature sequence as that of the genetic group oxy-1, whereas the SG271 clones displayed three different 16S rDNA signature sequences that also differed from those of the two genetic groups. Singular nucleotides were found within the rpoB sequence of the two strains, allowing for their distinction from the two genetic groups. All of these results, combined with those previously obtained by the ERIC-1R PCR method, indicate that strain SG271 is representative of a new K. oxytoca genetic group (oxy-3), whereas strain SG266 could not be classified.
先前在产酸克雷伯菌分类群中鉴定出的两个基因群（oxy-1和oxy-2）可通过四种独立的分子标记识别：（i）. ERIC-1R图谱，（ii）. 16S核糖体DNA（rDNA）特征序列，（iii）. rpoB基因特定片段中的单核苷酸，以及（iv）菌株bla(OXY)基因的类型（即bla(OXY-1)或bla(OXY-2)）。基于ERIC-1R图谱和bla(OXY)基因序列，产酸克雷伯菌菌株SG266和SG271无法归类到这些基因群中。鉴于bla(OXY-1)和bla(OXY-2)基因群之间的基因同一性百分比（86.8%±0.4%）以及一个bla(OXY)基因群内的同一性百分比（>99%），得出结论，菌株SG271的bla(OXY)基因代表一个新的bla(OXY)基因群（bla(OXY-3)），因为它与两个bla(OXY)基因群之间的平均同一性百分比分别为85.5%±0.2%和84.4%±0.4%。由于菌株SG266的相应百分比分别为95.0%±0.4%和86.2%±0.3%，因此无法对其bla(OXY)基因进行分类，故将其命名为bla(OXY-4)。只有在克隆实验后才能确定这两个菌株的16S rDNA特征序列。SG266克隆显示出与基因群oxy-1相同的特征序列，而SG271克隆显示出三种不同的16S rDNA特征序列，这些序列也与两个基因群的不同。在这两个菌株的rpoB序列中发现了单核苷酸，从而可将它们与两个基因群区分开来。所有这些结果，与先前通过ERIC-1R PCR方法获得的结果相结合，表明菌株SG271代表一个新的产酸克雷伯菌基因群（oxy-3），而菌株SG266无法归类。
