RESUMEN
Pneumocystis jirovecii is a human-specific species and causes fatal infections like P.jirovecii pneumonia (PCP) in immunocompromised persons. Although direct microscopy is the gold standard in the diagnosis of the microorganism, molecular methods such as polymerase chain reaction (PCR) are needed in non-human immune deficiency virus (HIV) immunosuppresive patients with low P.jirovecii burden. In this study, we aimed to evaluate the value of real-time PCR (Rt-PCR) in the laboratory diagnosis of P.jirovecii. Bronchoalveolar lavage (BAL) specimens of 658 patients sent to Dokuz Eylul University Hospital Central Medical Parasitology Laboratory on suspicion of PCP were included in the study. BAL fluids were evaluated for identification of P.jirovecii mitochondrial gene coding ribosomal large subunit (mtLSUrRNA) using Rt-PCR. In addition, Giemsa and Gomori's methenamine silver (GMG) staining assays were applied to all samples and nested PCR (n-PCR) assay was applied to positive samples detected by real time PCR. Ninety-two (14.3%) of these samples were positive by Rt-PCR. Of these 92 patients, 85 (92.4%) were positive with n-PCR. Only seven of the specimens had P.jirovecii cysts and trophozoites with microscopic examination. The mean cycle threshold (CT ) value of Rt-PCR positive patients was 29.7 (18.17 ≤ CT ≤ 37.96). P.jirovecii load in these patients was calculated as 2.6 x 101-6.15 x 107 copies/ml. The difference between the mean CT values of n-PCR positive and negative results was statistically significant (p< 0.01). The CT values of Rt-PCR of the samples with positive microscopy were; 18.2, 20.9, 22.2, 24.3, 24.7, 26.5, 29.7. The difference between the CT means of the samples with positive and negative microscopy was statistically significant (p< 0.05). When positive patients were grouped according to their diagnosis; the lowest mean CT value (CTmean= 24.8) was found in HIV-positive patients. On the other hand, CT values were found to be significantly lower in the organ transplantation patients (CTmean= 26.15) and in the collagen-vascular-inflammatory patient group (CTmean= 27.8). This study demonstrated that Rt-PCR was the effective method in the diagnosis of P.jirovecii in the laboratory. Conventional n-PCR method was found to be more unsuccessful than Rt-PCR in the presence of very low density organism; direct microscopy is generally found to be positive in samples with a higher burden of P.jirovecii.
Asunto(s)
Pneumocystis carinii , Neumonía por Pneumocystis , Reacción en Cadena en Tiempo Real de la Polimerasa , Líquido del Lavado Bronquioalveolar/microbiología , Técnicas de Laboratorio Clínico/normas , Humanos , Pneumocystis carinii/genética , Neumonía por Pneumocystis/diagnóstico , Neumonía por Pneumocystis/microbiología , Reacción en Cadena en Tiempo Real de la Polimerasa/normas , Sensibilidad y EspecificidadRESUMEN
OBJECTIVE: Intestinal parasitic diseases are important public health problems in our country as well as in the world. In this study, intestinal parasites were investigated in patients admitted to Dokuz Eylül University Hospital (DEUH) with various gastrointestinal system complaints. METHODS: Patients (n=18460) who were referred to the DEUH Central Parasitology Laboratory between January 2011 and December 2018, were included in the study. Fecal samples were examined with Nativ-lugol method and then formol ethyl-acetate precipitation method was applied. Trichrome and kinyoun acid-fast stainings were performed on the necessary samples. Demographic data of the patients were obtained from the hospital's and laboratory's information operating system. RESULTS: One or more parasites were detected in 6% (1128) of 18460 patients examined. The mean age of the patients with parasites was 39.7 (±23.1) years, of which 53.3% were male and 47.6% were female. The distribution of parasites detected were as follows; 4.8% (879) Blastocystis hominis, 0.7% (135) amoebas other than Entamoeba histolytica/dispar, 0.4% (70) Giardia intestinalis, 0.3% (49) Enterebius vermicularis, 0.1% (21) Entamoeba histolytica/dispar, and 0.01% (10) other rare parasites. CONCLUSION: Our study shows that intestinal parasitic infections are still an important public health problem in our region and that there is a decrease in their incidence.