We previously demonstrated the ability of an orally administered attenuated Salmonella enterica serovar Typhimurium strain expressing the protective antigen (PA) of Bacillus anthracis to confer protection against lethal anthrax aerosol spore challenge [1]. To extend the utility of this approach to humans we constructed variants of S. enterica serovar Typhi Ty21a, an attenuated typhoid vaccine strain licensed for human use, which expressed and exported PA via two distinct plasmid-based transport systems: the Escherichia coli HlyA haemolysin and the S. Typhi ClyA export apparatus. Murine immunogenicity studies confirmed the ability of these constructs, especially Ty21a expressing the ClyA-PA fusion protein, to stimulate strong PA-specific immune responses following intranasal immunization. These responses were further enhanced by a subsequent boost with either parenterally delivered recombinant PA or the licensed US human alum-adsorbed anthrax vaccine (AVA). Anthrax toxin neutralizing antibody responses using this prime-boost regimen were rapid, vigorous and broad in nature. The results of this study demonstrate the feasibility of employing a mucosal prime with a licensed Salmonella Typhi vaccine strain followed by a parenteral protein boost to stimulate rapid protective immunity against anthrax.

This article was corrected on November 23, 2020, to fix results of mistakenly included analyses and coding errors.

Luciferase reporter phages (LRPs) have proven to be efficient tools for drug susceptibility testing of Mycobacterium tuberculosis. Luminometric detection of LRP activity offers higher sensitivity and quantitative results, while a Polaroid film detection method offers a "low-tech" inexpensive alternative that is called the Bronx box. In this work we evaluated, improved, and compared the performance of the luminometer and the Bronx box formats for drug susceptibility testing with LRPs by using 51 clinical isolates of M. tuberculosis, with the agar proportion method (PM) serving as reference. The sensitivity in detecting resistance to isoniazid and rifampin, antibiotics that define multidrug resistance (MDR), was 100% for both methods. The turnaround time for results was reduced from 3 weeks for PM to 54 or 94 h for luminometry or the Bronx box, respectively. These results support the utility of LRPs as a screening test for the surveillance of MDR tuberculosis.Early diagnosis of tuberculosis (TB) and drug-resistant TB allows the prescription of appropriate antibiotic regimens, leading to more efficient control of the disease (15). The increase in incidence of multidrug-resistant (MDR) TB (4) has clearly established the need to improve the drug susceptibility techniques available. Mycobacteriophages (phages) are promising tools for the early diagnosis of drug-resistant TB because they offer a phenotype-based result in a turnaround time similar to that of some molecular approaches at a low cost. Luciferase reporter phages (LRPs) are phages harboring the fflux reporter gene, which codes for the firefly luciferase, which in turn catalyzes a reaction that releases light in the presence of its substrate luciferin and ATP. LRPs are able to infect, replicate, and express their genome and the fflux gene only within viable mycobacterial cells. Luciferase activity can then be detected only if cellular ATP is present (8), allowing detection of M. tuberculosis in clinical samples (2, 13). If a decontaminated clinical specimen containing M. tuberculosis is pretreated with antibiotics and is then infected with LRPs, light emission will be proportional to mycobacterial viability; hence, LRPs are promising candidates for drug susceptibility testing (3,12,14). Detection of the luciferase activity is achieved by means of a luminometer or photographic film. The luminometer offers higher sensitivity and quantitative results (1, 2); the Polaroid film offers an inexpensive, "low-tech" alternative that is called the Bronx box (14), but its performance as a clinical tool requires further evaluation.In this work we improve, evaluate, and compare the performance of the luminometer and the Bronx box formats for drug susceptibility with LRPs by using clinical isolates of M. tuberculosis obtained from a focus presenting high levels of resistance, with the agar proportion method (PM) (9) LRPs. Stocks of phages phAE85 (3, 12) and phAE142 (1, 2) were amplified as previously indicated. Titers of phAE85 and phAE142 were 5 ϫ 10 8 and 7.5 ϫ 10 6 PFU/...

Introducción. La leptospirosis es una enfermedad zoonótica urbana y rural que afecta a los humanos en todos los continentes, aunque su transmisión y presentación clínica puede variar. En Colombia hay poca información acerca de la importancia de la leptospirosis en entornos urbanos. Objetivos. Establecer la seroprevalencia de infección por Leptospira en humanos, identificar la reactividad serológica y explorar factores asociados con la seropositividad. Materiales y métodos. Se realizó un estudio transversal en 259 habitantes de barrios periféricos de Cali, estratificado por sexo y edad. Se obtuvo información general de cada persona, tiempo de residencia en el barrio, ocupación, exposición a fuentes contaminadas como agua o animales, y suero para la prueba de microaglutinación con 19 serovares de Leptospira. Resultados. La población evaluada correspondió principalmente a estudiantes (37,1%), amas de casa (32%) y trabajadores en oficios varios (24,6%). Se encontraron anticuerpos antiLeptospira en 23,3% (IC95% 18,3 a 28,3) de las personas, siendo más frecuente en mayores de 57 años y significativamente mayor en hombres que en mujeres (p = 0,045). Se encontró asociación entre la seropositividad y el contacto con animales (p = 0,038). De los 19 serovares evaluados, se detectó reactividad frente a 16, pero los títulos de anticuerpos fueron bajos. Conclusiones. La alta prevalencia de infección encontrada en el estudio sugiere la transmisión frecuente de leptospiras en barrios de Cali considerados de alto riesgo. Se destaca el contacto con animales como un factor asociado con la presencia de anticuerpos contra leptospiras.Palabras clave: estudios seroepidemiológicos, leptospirosis, anticuerpos, Colombia. Seroprevalence of Leptospira infection in inhabitants of peripheral neighborhoods in Cali, ColombiaIntroduction. Leptospirosis is a zoonotic disease with varying modes of transmission and clinical expression, which affects humans inhabiting urban and rural areas worldwide, In Colombia, little is known regarding leptospirosis in urban settings. Objectives. To establish the seroprevalence of leptospiral infection in humans, to assess the serological reactivity and to identify factors associated with seropositivity. Materials and methods. We conducted an infection prevalence study in 259 inhabitants of peripheral neighborhoods in the city of Cali, Colombia, stratified by sex and age. Sociodemographic information, time residing in the same neighborhood, occupation, exposure to potentially infectious sources like water or animals, and serum used in a Microagglutination test against 19 Leptospira serovars were obtained. Results. The population was composed mainly of students (37.1%), housewives (32%) and workers in non-formal activities (24.6%). The prevalence of anti-Leptospira antibodies was 23.3% 3), with high frequency in people older than 57 years of age and significantly higher in men than women (p=0.045). There was an association between the presence of antibodies and contact with animals (p=0.038). There was reactivity...