Misidentification of Lophomonas Blattarum: Methodological Flaws and Taxonomic Confusion in Molecular Diagnostics

Lophomonas blattarum is a protozoan, which is controversial regarding pathogenicity in the respiratory disease, and identification methods. This study investigated the presence of this protozoan in patients admitted to the intensive care unit (ICU) to assess these controversies.

Samples of 83 patients hospitalized in the ICU ward of Afzalipoor, Shafa, and Shahid Bahonar hospitals (Kerman, Iran) were collected. The samples were examined using microscopy and real-time polymerase chain reaction (PCR) to check the presence of Lophomonas blattarum. Then, the efficiency of the method used was investigated using bioinformatics studies and the presence of Trichomonas tenax in the samples was investigated.

Of 83, 38 (46%) were female, 45 (54%) were male, and their age was 46.6 ± 14.45 years. Microscopic examination did not show any in the samples. The real-time PCR method showed 16 positive samples with primers that had been reported in other studies for Lophomonas blattarum. The bioinformatics study showed the method introduced in the other studies lacks the efficiency and specificity, and there is no information in the databases to design a molecular method based on the PCR for identification of Lophomonas blattarum. The results of examining the presence of Trichomonas tenax using the real-time PCR method showed that 16 samples with a positive result for Lofomonas blattarum contained Trichomonas tenax, which indicated that a misidentification had probably occurred.

The current methods that are used to identify Lophomonas blattarum do not have the sensitivity and specificity required to identify this protozoan.