New detection of flinders island spotted fever (due to Rickettsia honei infection) in new south wales: A case of fulminant septic shock and multi-organ failure

Abstract

We report a case of a new location and severe infection for Rickettsia honei. A 76-year-old man, five days after returning from a camping trip to Grafton and Coffs Harbour, presented to the emergency department with two-day history of widespread rash, fever, rigors, confusion and decreasing mobility with rapid deterioration. He eventually progressed into multi-organ failure requiring dialysis, vasopressor support and intubation. On day 2, rickettsial infection was suspected. Therefore, a blood ethylene diamine triacetic acid (EDTA) tube for rickettsial polymerase chain reaction (PCR) and serology (microimmunofluorescence assay) were sent to the Australian Rickettsial Reference Laboratory. He was started on oral doxycycline 100 mg BD via nasogastric tube but did not improve. On day 4, his treatment was escalated to intravenous azithromycin 500 mg daily and intravenous doxycycline 100 mg BD (Special Access Scheme Category A) given non-improvement and doubtful absorption of oral doxycycline considering high vasopressor support. He rapidly improved 48 hours later with reducing organ support, extubated and subsequently discharged from ICU on Day 8. Subsequently, his serology and PCR suggested Spotted Fever Group Rickettsia. Further amplification of the citrate synthase and outer membrane protein A genes confirmed Rickettsia honei infection, which had not been detected in New South Wales previously.