柠檬无色藻菌的鉴定方法及体外药敏特点

Clinical and microbiological characteristics of Leuconostoc citreum infection

目的总结临床少见菌柠檬无色藻菌的鉴定过程,认识柠檬无色藻菌的耐药特点,并对该菌感染的临床特征进行分析。方法菌株分离培养后,采用传统的形态、生理生化表型和VITEK-2全自动细菌鉴定仪与16S rRNA序列分析相结合的方法来鉴定菌株。结果多次传代后,综合菌株形态、生理生化表型、VITEK-2全自动细菌鉴定仪以及16S rRNA序列分析的结果,确定该分离株为柠檬无色藻菌;药物敏感定量试验显示红霉素、四环素、复方新诺明、三代头孢菌素及喹诺酮类药物均敏感,唯有万古霉素和替考拉宁耐药。结论柠檬无色藻菌引起的血流感染比较罕见;16S rRNA基因序列分析方法可以较好地鉴定常规方法难以鉴定的不典型及罕见菌株。对万古霉素及替考拉宁耐药可以作为无色藻菌与其他阳性球菌鉴别的重要依据。

Objective To investigate the clinical and microbiological characteristics of the Leuconostoc citreum infection.Methods The pure culture of the isolated strain was analyzed using conventional physiological and biochemical tests,and then the species identification were carried out using an automated machine（VITEK-2） together with 16S rRNA gene sequencing.Micro dilution method was used for antibiotic susceptibility testing.Results After repeated passage,the strain morphology,a series of biochemical experiment,combined with 16 s RNA sequence analysis,the isolate was identified as Leuconostoc citreum.Susceptibility testing showed resistant to vancomycin,teicoplanin,susceptible to erythromycin,tetracycline,Trimethoprim-sulfamethoxazole,third-generation cephalosporins and fluoroquinolones.Conclusion The Leuconostoc citreum can rarely cause blood infection,16 s rRNA gene sequence analysis would be a good method for identifying this species.Resistance to vancomycin,teicoplanin could be a very important characteristic for differentiating Leuconostoc citreum with other Gram-positive cocci.