Postoperative infection caused by Acinetobacter baumannii misdiagnosed as a free-living amoeba species in a humeral head hemiarthroplasty patient: a case report

Abstract

BackgroundAcinetobacter baumannii is ubiquitous, facultative intracellular, and opportunistic bacterial pathogen. Its unique abilities allow it to survive in a diverse range of environments, including health care settings, leading to nosocomial infections. And its exceptional ability to develop resistance to multiple antibiotics leaves few drug options for treatment. It has been recognized as a leading cause of nosocomial pneumonia and bacteremia over the world.Case presentationIn this case, a 73-year-old woman presented with a Neer Group VI proximal humeral fracture. Six hours after a successfully performed hemiarthroplasty, she developed continuous fever. Clinical examination revealed that the vitals were regular. Laboratory and radiographic examinations revealed only elevated procalcitonin levels. Blood culture revealed no bacterial or fungal growth. Cooling treatment and empirical broad-spectrum antibiotic therapy showed no apparent effect.ConclusionsWe report a postoperative infection caused by Acinetobacter baumannii. The infectious pathogen was identified via molecular DNA sequencing and was initially misidentified as a free-living amoeba species upon microscopic examinations. The patient was mistreated with antiamebic combination therapy. Her symptoms persisted for over 4 months and were eventually followed by her death.Electronic supplementary materialThe online version of this article (10.1186/s40249-018-0408-5) contains supplementary material, which is available to authorized users.

The abaI/abaR Quorum Sensing System Effects on Pathogenicity in Acinetobacter baumannii

“…It has been observed that lipids are the main carbon and energy source of Mycobacterium tuberculosis , which switches from carbohydrate utilization to the fatty acid utilization pathway for the establishment of a successful infection ( Mukhopadhyay et al, 2012 ). A. baumannii is a ubiquitous, facultative intracellular bacterial pathogen ( Tang et al, 2018 ). The Δ abaR mutant may enhance lipid transport and metabolism to play a protective role against the host.…”