Abstract

GARCIA-CORTEZ, Cynthia Yadira et al. Cutaneous Swab and Urine Samples Reliability to Detect Rickettsia rickettsii through PCR in hospitalized patients, Sonora. Biotecnia [online]. 2023, vol.25, n.1, pp.140-146.  Epub Aug 07, 2023. ISSN 1665-1456.  https://doi.org/10.18633/biotecnia.v25i1.1790.

Rocky Mountain spotted fever (RMSF) is an infectious disease confirmed through IgM and IgG determination obtained by indirect immunofluorescence, although it has limited clinical value since it requires up to three weeks to be reliable. Polymerase Chain Reaction (PCR) is an alternative for RMSF diagnosis in whole blood, but there is less certainty regarding its certainty when urine and tissue samples are used. This study aimed to estimate the reliability of PCR in skin swab and urine samples obtained from patients with suspected RMSF, comparing it with PCR results from whole blood samples. Samples from 110 suspected RMSF hospitalized patients, between September 2018 and October 2019, were analyzed. Reliability was calculated using the Kappa Coefficient (K). R. rickettsii was detected in 21 urine samples, finding substantial agreement (K = 0.607, 95 % CI (0.385, 0.844)); meanwhile, 3 skin swabs were positive, but without statistical significance (K = 0.417, 95 % CI (- 0.338, 1.172)). Our findings support that urine PCR is a reliable technique to confirm clinical suspicion of RMSF in hospitalized patients.

Keywords : Rocky Mountain spotted fever; PCR; early detection of disease; reliability.