Clinical utility of urinary antigen test and molecular method for detection of Legionella pneumophila.

Legionella pneumophila is gram-negative bacterium which causes Legionnaires’ disease and Pontiac fever.To determine the frequency of serogroup 1 and other serogroup of Legionellapneumophila in pneumonic patients and the clinical utilityofLegionellapneumoniaurinary antigen test (LPUAT)in terms of sensitivity and specificity andcomparethe results with q Real Time PCR using serum samples. A total of 100 pneumonic patients were enrolled in this studyduring a period between October 2016 to April 2017; all patients under therapy with antibiotics.Serum and urine specimens were obtained from all patients; urine samples were processed for urinary antigen test. Serum samples were collected and submitted to DNA extraction for detection of L. pneumophila mip gene by q RT PCRassay. The percentage of L. pneumophila in two hospitals In Baghdad was 30%. Of these 26% was serogroup 1 detected by UAT. In the other hand, 23 % of samples were positive by q RT- PCR based mip gene,of these 19 % were serogroup 1 and 4% were other serogroups. The sensitivity of UAT is high (P value< 0.001), which means statistically highlysignificance than q RT PCR. Legionellapneumophila urinary antigen test is a rapid tool for early diagnosis of Legionella infection which highlights the need of using this test in hospitals and health institutions and there is a high prevalence of L.pneumophila in Iraqthat refer to the necessity of considering this microorganism point of view in future studies for detection and treatment in pneumonic patients.