Gold Coast University Hospital, Southport, QLD, 4217, Australia.
South Eastern Area Laboratory Services, Sutherland Hospital, Caringbah, NSW, 2229, Australia.
Curr Top Microbiol Immunol. 2017;402:179-191. doi: 10.1007/82_2016_56.
The three recognised Photorhabdus species are bioluminescent Gram-negative bacilli of the family Enterobacteriaceae. They are all pathogenic to insects and form a symbiotic relationship with nematodes of the genus Heterorhabditis. P. luminescens and P. temperata are both harmless to humans whilst P. asymbiotica, on the other hand, is a human pathogen that is a symbiont of the newly described nematode vector, Heterorhabditis gerrardi. In this chapter, we review the epidemiological and clinical features of eighteen human cases of P. asymbiotica infection including fifteen from the published literature and three previously unreported cases. Human infection has been reported in the USA and Australia and probably occurs in other parts of Asia where it remains undocumented. Infection occurs most commonly in warmer months particularly after rainfall. Patients may have a history of recent exposure to sand or sandy soil. P. asymbiotica causes both locally invasive soft tissue infection and disseminated disease with bacteraemia. Soft tissue infection may be multifocal with involvement of more than one limb and the trunk. The organism is sensitive to a number of antibiotics in vitro, but treatment failures have been associated with the use of beta-lactams and aminoglycosides. We suggest treatment with a four-week course of an oral fluoroquinolone such as ciprofloxacin. The organism grows readily on standard media from specimens such as wound swabs, pus, blood and even sputum and can be identified in a clinical microbiology laboratory but the diagnosis needs to be considered. The correct diagnosis is most likely to be made where there is close cooperation between clinician and microbiologist.
三种公认的 Photorhabdus 物种是发光革兰氏阴性杆菌，属于肠杆菌科。它们对昆虫均具有致病性，并与异小杆线虫属的线虫形成共生关系。P. luminescens 和 P. temperata 对人类均无害，而另一方面，P. asymbiotica 是一种人类病原体，是新描述的线虫载体 Heterorhabditis gerrardi 的共生体。在本章中，我们回顾了 18 例人类 P. asymbiotica 感染的流行病学和临床特征，其中包括 15 例来自已发表的文献和 3 例以前未报道的病例。已在美国和澳大利亚报告了人类感染病例，并且可能在亚洲其他地区发生，但尚未记录在案。感染最常发生在温暖的月份，特别是在降雨后。患者可能有最近接触沙子或沙质土壤的病史。P. asymbiotica 可引起局部侵袭性软组织感染和播散性疾病伴菌血症。软组织感染可能是多灶性的，累及一个以上肢体和躯干。该生物体在体外对许多抗生素敏感，但与使用β-内酰胺类和氨基糖苷类抗生素相关的治疗失败。我们建议使用口服氟喹诺酮类药物（如环丙沙星）治疗 4 周疗程。该生物体可从伤口拭子、脓液、血液甚至痰液等标本中在标准培养基上良好生长，并且可以在临床微生物学实验室中鉴定，但需要考虑诊断。在临床医生和微生物学家之间密切合作的情况下，最有可能做出正确诊断。
