Potentially pathogenic free-living amoebae isolated from hospital wards with immunodeficient patients in Tehran, Iran

Area of Science:

• Environmental microbiology
• Hospital-acquired infections
• Public health

Background:

• Free-living amoebae (FLA) are ubiquitous microorganisms found in various environments.
• Immunocompromised patients in hospital settings are particularly vulnerable to opportunistic infections.
• Previous studies have not extensively documented FLA presence in Iranian hospital immunodeficiency wards.

Purpose of the Study:

• To investigate the occurrence and diversity of FLA in dust and biofilm samples from hospital wards catering to immune-compromised patients in Tehran, Iran.
• To identify specific FLA species and genotypes, with a focus on potential opportunistic pathogens.
• To assess the implications of FLA presence for patient safety and hospital hygiene.

Main Methods:

• Collection of 70 dust and biofilm samples from five university hospitals in Tehran, Iran.
• Examination of samples using both culturing techniques and molecular identification methods.
• Application of specific primer sets for the molecular identification of Acanthamoeba, vahlkampfiid amoebae, and Hartmannella.

Main Results:

• A total of 37 out of 70 samples (52.9%) tested positive for FLA.
• Acanthamoeba, specifically the T4 genotype, was the most frequently isolated FLA.
• Other identified FLA included Acanthamoeba T5 genotypes, Hartmannella vermiformis, and Vahlkampfia avara.
• The T4 genotype of Acanthamoeba was detected on medical instruments, such as an oxygen mask.

Conclusions:

• The significant prevalence of FLA, particularly Acanthamoeba T4, in hospital immunodeficiency wards highlights a potential risk to susceptible patients.
• The presence of FLA on medical devices warrants increased attention to disinfection and infection control measures.
• This study provides the first report of these FLA in Iranian immunodeficiency wards and the first identification of Acanthamoeba T5, Hartmannella, and Vahlkampfia in biofilms within the country.