Comparison of a SYBR green I-based assay with a histidine-rich protein II enzyme-linked immunosorbent assay for in vitro antimalarial drug efficacy testing and application to clinical isolates.

In vitro drug susceptibility testing with the malaria parasite has been used to assess the antimalarial activities of new compounds and to monitor drug resistance in field isolates. We investigated the validity of a SYBR green I fluorescent-based assay under various culture conditions and compared the assay results to those of previously published histidine-rich protein II (HRPII) enzyme-linked immunosorbent assay (ELISA) methods. Reference strains of Plasmodium falciparum were cultured in vitro by using standard conditions in complete medium with and without phenol red before they were dispensed into 96-well plates predosed with chloroquine, mefloquine, or quinine. Following incubation, the culture supernatants were divided and the 50% inhibitory concentrations (IC50s) were determined by using a SYBR green I-based method and the HRPII capture ELISA method. There were no significant differences in IC50 values when phenol red was included in the medium. The IC50s and the IC90s of the antimalarials tested by both methods were similar or identical for each of the reference strains. Fresh clinical isolates of P. falciparum collected from imported cases of malaria in Lyon, France, were tested for in vitro resistance to chloroquine and mefloquine by using the validated SYBR green I and HRPII ELISA methods. The SYBR green I-based method was able to calculate IC50 and IC90 values similar or identical to those calculated by the HRPII assay with fresh clinical samples without removal of white blood cells. The SYBR green I-based method for determination of drug sensitivity levels produced results comparable to those produced by other methods, showing that this method can be used routinely to conduct surveillance for drug resistance in P. falciparum with fresh or cultured parasites.

Outbreak of gastroenteritis at a Peruvian naval base.

In April of 2003, an outbreak of gastroenteritis was reported in a training command (Centro de Instrucción Técnica y Entrenamiento Naval (CITEN)) at a Peruvian naval base located near Lima, Peru. The Naval Medical Research Center Detachment, in collaboration with the National Peruvian Naval Hospital, conducted an investigation to determine the causative agent and potential source of the outbreak. Between April 3 and 5, 172 (16%) of 1,092 military trainees reported to the CITEN clinic with diarrhea. Of 74 trainees for whom bacterial cultures were performed, Shigella spp. were isolated from 5 (6.8%), Campylobacter spp. from 5 (6.8%), and enterotoxigenic Escherichia coli from 2 (2.7%). Pathogenic parasites were identified in 22 of 64 (34%) trainees for whom microscopic observation for ova and parasites was performed. Stool samples from asymptomatic controls could not be collected, thus we were unable to confirm that the enteropathogens isolated were the etiologic agent(s). Several food items and the hands of food handlers were contaminated with coliform bacteria and drinking water was not adequately chlorinated. Preventative measures have since reduced the number of diarrhea cases at the CITEN.

Outbreak of cyclosporiasis at a naval base in Lima, Peru.

Cyclospora cayetanensis is emerging as an important cause of food-borne diarrheal outbreaks, especially in developed regions like the United States and Europe. We describe an outbreak of cyclosporiasis in Peruvian naval recruits that we believe to be the first among a local population in a developing region.

Comparison of meglumine antimoniate and pentamidine for peruvian cutaneous leishmaniasis.

Pentamidine was compared with meglumine antimoniate (Glucantime) for 80 patients with cutaneous leishmaniasis due to Leishmania braziliensis in Peru. Of the 40 patients administered Glucantime (20 mg of antimony [Sb]/kg/day intravenously for 20 days), 31 cured (78%), 6 failed (15%), of which 5 were due to relapse, and 3 were lost to follow-up (7%). Of the 40 patients administered pentamidine (2 mg/kg every other day for seven injections), 14 were cured (35%), 23 failed (58%), and 3 were lost to follow-up (7%). Five pentamidine failures were due to relapse, and 14 failures were due to the presence of parasites two weeks after therapy. Both regimens were well tolerated. Gastrointestinal, musculoskeletal, and total adverse events were not statistically different in either group. Elevations in levels of liver enzymes and pancreatic enzymes were statistically higher in the Glucantime group, but no patient terminated therapy prematurely. In this study, Glucantime was more effective than pentamidine for treatment of L. braziliensis cutaneous leishmaniasis in Peru based on parasitologic as well as clinical criteria.