Department of Environmental Health Science, 206 Environmental Health Science Building, University of Georgia, Athens, Georgia 30602-2102, USA.
J Food Prot. 2010 May;73(5):849-54. doi: 10.4315/0362-028x-73.5.849.
Cronobacter sakazakii (Enterobacter sakazakii) is an emerging pathogen that has been isolated from powdered infant formula and associated with outbreaks of infection in infants in neonatal intensive care units. In a previous study, we observed that neonatal CD-1 mice are susceptible to C. sakazakii infection and that the pathogen invades brain, liver, and cecum tissues. The study objective was to compare the virulence of three strains of C. sakazakii in neonatal CD-1 mice. The strains tested were MNW2 (a food isolate), SK81 (a clinical isolate), and 3290 (a clinical isolate). Timed-pregnant CD-1 mice were allowed to give birth on gestation day 19 or 20. Neonatal mice were sexed and culled to 10 per litter, each having five males and five females. Neonates were orally gavaged with C. sakazakii strains MNW2, SK81, or 3290 at doses ranging from 10(2.8) to 10(10.5) CFU on postnatal day 3.5. Pups surviving to postnatal day 10.5 were euthanized, and brain, liver, and cecum tissues were excised. C. sakazakii was isolated from all three tissues in mice treated with C. sakazakii, regardless of strain. C. sakazakii strain 3290 was significantly more invasive in brains (42.1% of mice) than were strains MNW2 (6.7%) and SK81 (15.9%). Mortality was observed for all strains of C. sakazakii tested, with SK81 being significantly more lethal (5.6%) than MNW2 (1.2%) or 3290 (0.6%). Our findings suggest that invasiveness does not necessarily correlate with mortality among different strains of C. sakazakii, and the clinical isolates are more virulent than the food isolate.
阪崎克罗诺杆菌（肠杆菌科阪崎氏菌）是一种新兴的病原体，已从婴儿配方奶粉中分离出来，并与新生儿重症监护病房中婴儿感染的爆发有关。在之前的一项研究中，我们观察到新生 CD-1 小鼠易感染阪崎克罗诺杆菌，该病原体可入侵大脑、肝脏和盲肠组织。本研究的目的是比较三种阪崎克罗诺杆菌菌株在新生 CD-1 小鼠中的毒力。测试的菌株为 MNW2（一种食品分离株）、SK81（一种临床分离株）和 3290（一种临床分离株）。让受孕的 CD-1 小鼠在妊娠第 19 或 20 天分娩。新生小鼠进行性别鉴定，并每窝 10 只，每窝 5 只雄性和 5 只雌性。新生小鼠于出生后第 3.5 天用剂量为 10(2.8)至 10(10.5)CFU 的 MNW2、SK81 或 3290 阪崎克罗诺杆菌菌株经口灌胃。存活至出生后第 10.5 天的幼鼠被安乐死，并切除大脑、肝脏和盲肠组织。用阪崎克罗诺杆菌处理的小鼠的所有三种组织中均分离出了阪崎克罗诺杆菌，而与菌株无关。与 MNW2（6.7%）和 SK81（15.9%）相比，菌株 3290 明显更易入侵大脑（42.1%的小鼠）。所有测试的阪崎克罗诺杆菌菌株均观察到死亡率，其中 SK81 明显比 MNW2（1.2%）或 3290（0.6%）更致命。我们的研究结果表明，侵袭性不一定与不同菌株的阪崎克罗诺杆菌的死亡率相关，临床分离株比食品分离株更具毒力。
