儿童血流感染病原菌人苍白杆菌的流行种系及耐药特点

Epidemic strains and drug-resistance of Ochrobactrum anthropi in bloodstream infection in children

目的了解儿童血流感染病原菌人苍白杆菌的流行种系及耐药特点,为临床诊疗提供依据。方法收集湖南省儿童医院2010年1月-2017年12月收治的全自动微生物鉴定分析仪鉴定为人苍白杆菌败血症患儿的194株病原菌菌种,采用质谱仪重新鉴定,再取其中61株用基因测序法鉴定,同时对药物结果进行统计。结果 194株原鉴定为人苍白杆菌的菌株有163株确定为人苍白杆菌,占84.0%,其他31株分别是解糖精假苍白杆菌26株,假贵格纳苍白杆菌4株,中间苍白杆菌1株。苍白杆菌对氨曲南100%耐药。人苍白杆菌对氨苄西林、哌拉西林/他唑巴坦、头孢唑啉、头孢他啶耐药率达90.0%以上,对左氧氟沙星、亚胺培南耐药率为0%,对环丙沙星、丁胺卡那、庆大霉素耐药率低于2.0%,对复方新诺明、头孢吡肟耐药率小于21.5%。假苍白杆菌对氨苄西林、头孢唑啉耐药率小于50%,对头孢他啶、头孢吡肟、丁胺卡那、庆大霉素耐药率低于10.0%。对左氧氟沙星、环丙沙星、哌啦西林/他唑巴坦、复方新诺明耐药率为0%,对亚胺培南则有16.1%的耐药率。人苍白杆菌有AmpC/R基因,假苍白杆菌没有。结论湖南省儿童苍白杆菌血流感染的流行菌株主要是人苍白杆菌,其次为解糖精假苍白杆菌和假贵格纳苍白杆菌等。传统仪器无法区分苍白杆菌的种系,而人苍白杆菌和假苍白杆菌的耐药性有差别。人苍白杆菌可选用头孢吡肟,重症患儿可用亚胺培南;假苍白杆菌可选用头孢他啶、头孢吡肟、哌啦西林/他唑巴坦。

Objective To study the epidemic strains and drug resistance of Ochrobactrum anthropi in bloodstream infection in children,and to provide evidence for clinical diagnosis and treatment.Methods One hundred and ninety-four strains of Ochrobactrum anthropi identified by automatic microbial identification analyzer were collected from children with Ochrobactrum anthropi sepsis in Hunan Children’s Hospital from January 2010 to December 2017.The strains were re-identified by mass spectrometry,of which 61 strains of Ochrobactrum anthropi were identified by gene sequencing,and the results of drug resistance were statistically analyzed.Results Mass spectrometry analysis identified that 84.0%(163/194)strains of bacteria were Ochrobactrum anthropi,and other 31 strains of bacteria included Pseudochrobactrum saccharolyticum(26/31),Ochrobactrum pseudogrignonense(4/31)and Ochrobactrum intermedium(1/31).Ochrobactrum was resistant to aztreonam(100%).The resistance rates of Ochrobactrum anthropi to ampicillin,piperacillin/tazobactam,cefazolin and ceftazidime were all over 90.0%,those to levofloxacin and imipenem 0.0%,those to ciprofloxacin,amikacin and gentamicin less than 2.0%,and those to compound sulfamethoxazole and cefepime less than 21.5%.The resistance rates of Pseudochrobactrum to ampicillin and cefazolin were less than 50%,those to ceftazidime,cefepime,amikacin and gentamicin less than 10.0%,those to levofloxacin,ciprofloxacin,piperacillin/tazobactam,and compound sulfamethoxazole 0.0%,and those to imipenem were 16.1%.Gene sequencing analysis showed that Ochrobactrum anthropi carried the Amp C/R gene,but Pseudochrobactrum did not.Conclusions The main epidemic strains in children with bloodstream infection caused by Ochrobactrum in Hunan Province were Ochrobactrum anthropi,followed by Pseudochrobactrum saccharolyticum and Ochrobactrum pseudogrignonense.Traditional instruments cannot distinguish the strains of Ochrobactrum,but the drug resistance results are different between Ochrobactrum anthropi and Pseudochrobactrum.Cefepime can be used for the treatment of Ochrobactrum anthropi infection,imipenem for severe infection in pediatric patients,and ceftazidime,cefepime,piperacillin/tazobactam for Pseudochrobactrum bacteremia infection.