Taniguchi Takako, Saeki Yuji, Okayama Akihiko, Hayashi Tetsuya, Misawa Naoaki
Center for Animal Disease Control, University of Miyazaki, Miyazaki, Japan.
Clinical Laboratory, University of Miyazaki Hospital, Miyazaki, Japan.
Microbiol Immunol. 2017 Feb;61(2):57-63. doi: 10.1111/1348-0421.12472.
Although Helicobacter cinaedi was initially considered an opportunistic pathogen in immunocompromised patients, it was later shown to also infect immunocompetent and healthy individuals. Sporadic bacteremia due to H. cinaedi has frequently been reported; however, whether the bacterium can be translocated after passage through the intestinal mucosa remains unclear. In the present study, a preclinical small animal model that faithfully reproduces H. cinaedi infection in humans was developed. Balb/c male mice were orally inoculated with a single dose of 6.8 × 10 CFU of a human clinical H. cinaedi strain. The organism persistently colonized the intestinal tract of the mice, particularly the cecum and colon, for at least 56 days, and the bacteria were excreted in the feces. Although inoculated bacteria were recovered from the spleen, liver, kidney, lung, bladder and mesenteric lymph nodes during the first 2 weeks of bacteremia, the organism was not isolated from these organs after 4 weeks, suggesting that complement- and antibody-mediated serum sensitivity account for the relatively low frequency of systemic infection. However, H. cinaedi was isolated from the biceps femoris, triceps branchii, latissimus dorsi, and trapezius muscles beyond 2 weeks after infection and after production of specific anti-H. cinaedi IgM and IgG antibodies. The present findings suggest that experimental infection of Balb/c mice with H. cinaedi may be a useful model for further studies of H. cinaedi pathogenesis, prophylaxis or therapeutic interventions in vivo.
虽然嗜人埃希杆菌最初被认为是免疫功能低下患者的机会致病菌，但后来发现它也可感染免疫功能正常的健康个体。嗜人埃希杆菌引起的散发性菌血症已有多次报道；然而，该细菌穿过肠黏膜后是否会发生易位仍不清楚。在本研究中，建立了一种能忠实再现人类嗜人埃希杆菌感染情况的临床前小动物模型。给雄性Balb/c小鼠口服接种单剂量6.8×10 CFU的一株人类临床嗜人埃希杆菌菌株。该菌在小鼠肠道中持续定植，尤其是在盲肠和结肠，至少持续56天，且细菌随粪便排出。虽然在菌血症的前2周从脾脏、肝脏、肾脏、肺、膀胱和肠系膜淋巴结中分离出了接种的细菌，但4周后在这些器官中未再分离到该菌，这表明补体和抗体介导的血清敏感性导致全身感染的频率相对较低。然而，在感染2周后及产生特异性抗嗜人埃希杆菌IgM和IgG抗体后，从股二头肌、肱三头肌、背阔肌和斜方肌中分离出了嗜人埃希杆菌。本研究结果表明，用嗜人埃希杆菌对Balb/c小鼠进行实验性感染可能是进一步研究嗜人埃希杆菌发病机制、体内预防或治疗干预的有用模型。
