Prevalence of Acanthamoeba spp. in Tasmanian intensive care clinical specimens

Acanthamoebae are ubiquitous free-living environmental amoebae that may occasionally cause keratitis, granulomatous encephalitis, cutaneous lesions and systemic disease in humans. Acanthamoeba spp. have been implicated as a vehicle by which a number of common bacterial causes of healthcare-associated pneumonia may enter the lungs. Limited evidence has been found implicating Acanthamoeba spp. as a primary cause of pneumonia and urinary catheter colonization in intensive care patients.

To explore the possibility of colonization of the respiratory and urinary tracts of intensive care patients with free-living amoebae.

Thirty-nine catheter urines, 50 endotracheal trap sputa and one general ward sputum sample from 45 patients and nine intensive care unit (ICU) environmental water samples were collected during a four-and-half-month period in the Royal Hobart Hospital from August 2011.

Acanthamoebae were isolated by culture and detected by polymerase chain reaction in two sputum samples from a single patient, taken one week apart. A single Acanthamoeba species isolate was detected by culture only from the ICU environment.

Colonization of ICU patients' respiratory tracts with Acanthamoeba spp. does occur. This may have significance for the role of acanthamoebae as a source of bacterial pathogens in intensive therapy patients' respiratory tracts.