Moving forward Strongyloides stercoralis detection, studying molecular typing as infection follow up strategy in immunocompromised patients.

REPETTO, S.; ARGÜELLO, L.; ESTELA I. BATALLA

Congreso; 18th International Congress on Infectious Diseases. CABA, Argentina, Marzo 2018.; 2018

Moving forward Strongyloides stercoralisdetection, studying molecular typing asinfection follow up strategy inimmunocompromised patientsS. Repetto 1,∗, L. Argüello 1, E. Batalla 1, J. Burgos 2,S. Gonzalez Cappa 1, C. Alba Soto 1, M. Risso 1, P.Ruybal 11 Universidad de Buenos Aires, Instituto deInvestigaciones en Microbiología y ParasitologíaMédica, Caba, Argentina2 Universidad de San Martín, Instituto deInvestigaciones Biotecnológicas, San Martín,ArgentinaBackground: Strongyloides stercoralis is a geohelminth whichaffects 10-40% of the world population in tropical and subtropical areas. It produces chronic infections and severe symptoms inimmunocompromised patients with high mortality. Although theparasitological cure is defined as the absence of larvae after oneyear of treatment, we have observed reactivations after the secondyear. We evaluated genetic diversity and its possible associationwith the clinical characteristics and evolution of this parasitosis.Methods & Materials: Twenty-two patients (18 immunocompromised) with diagnosis and follow-up of strongyloidosis fromArgentina, Bolivia, Paraguay, Peru and Dominican Republic wereevaluated. The DNA extracted from stool sample at the time ofdiagnosis was used as a template for amplification and sequencingof a 404 bp region of the mitochondrial gene cox1. The analysis of sequences was: consensus assembly (STADEN), alignment(MEGA6), haplotype resolution (PHASE, DNAsp), allele coding anddiscriminatory power calculation (PD, MLSTest). Sequences wereanalyzed in the context of sequences of S. stercoralis (581), S.fuelleborni, S. ratti, S. venezuelensis, S. planiceps, S. mirzai and S.papillosus. Results were expressed in frequencies and percentages.Level of significance was p < 0.05. Associations between categoricalvariables were analyzed by Fisher’s test and RR (relative risk).Results: From 80 haplotypes, 65 corresponded to the species S.stercoralis (PD = 0.774) with HP24 being the most frequent (26%).Eight haplotypes corresponded to cases from Latin America and 6of them to patients in follow-up (HP24, 34, 42-45). HP24 and HP43were found in 72.7% and 27.3% of cases, respectively. A 62.5% ofpatients with HP24 did not present symptoms and 11 presentedparasitological reactivation without being associated with the mostfrequent haplotypes (p > 0.05). However, in all immunocompromised patients who reactivated (7/18), the HP24 variant of theparasite was detected. The presence of HP24 increased the risk ofreactivation with a RR of 2.16 (p < 0.05).Conclusion: HP24 variant has been described in humans in Asiaand Latin America. Its wide geographical distribution and high frequency would describe a variant with high “fitness”. In this context,this haplotype would allow to predict reactivations in immunocompromised patients, providing new tools for clinical behavior.