Single-cell genomics reveals population structures from in vitro evolutionary studies of Salmonella.

Single-cell DNA sequencing has the potential to reveal detailed hierarchical structures in evolving populations of cells. Single cell approaches are increasingly used to study clonal evolution in human ageing and cancer but have not yet been deployed to study evolving clonal microbial populations. Here, we present an approach for single bacterial genomic analysis for in vitro evolution experiments using FACS isolation of individual bacteria followed by whole-genome amplification and sequencing. We apply this to the experimental evolution of a hypermutator strain of Salmonella in response to antibiotic stress (ciprofloxacin). By analysing sequence polymorphisms in individual cells from populations we identified the presence and prevalence of sub-populations which have acquired polymorphisms in genes previously demonstrated to be associated with ciprofloxacin susceptibility. We were also able to identify that the population exposed to antibiotic stress was able to develop resistance whilst maintaining diversity. This population structure could not be resolved from bulk sequence data, and our results show how high-throughput single-cell sequencing can enhance experimental studies of bacterial evolution.

Absence of hypoxia events in the adjacent coastal waters of Grijalva-Usumacinta river, Southern Gulf of Mexico.

Globally, oxygen concentration in many coastal areas is depleting. River nutrient discharges may produce hypoxia events. The Southern Gulf of Mexico receives the discharges of the Grijalva-Usumacinta River System, the second largest in the Gulf of Mexico. To evaluate the influence of river discharges on dissolved oxygen concentrations in the receiving coastal ecosystem, we studied the variation of physicochemical variables in the water column. During the dry season, the influence of the river waters to the coastal area is scarce, but during the rainy season the river plume reached ~9 km offshore. The lowest concentration of dissolved oxygen (3.6 mg L-1) was observed within the river plume. We concluded that, in the studied area, hypoxia events (oxygen concentrations ≤ 2 mg L-1) would occur during the rainy season, low winds and in deeper waters (>80 m depth).

Síndrome de Moebius: manifestaciones neurológicas, musculoesqueléticas y del lenguaje / Moebius syndrome: Neurological, musculoskeletal and speech anomalies

El síndrome de Moebius es una enfermedad congénita caracterizada por parálisis facial no progresiva y alteración de la abducción ocular de uno o ambos ojos por compromiso del VI par, pudiendo extenderse a otros pares oculomotores, así como al IX, X y XII. Se ha asociado con manifestaciones musculoesqueléticas y epilepsia. Presentamos el caso de un preescolar con antecedente de intento fallido de la madre de interrupción voluntaria del embarazo en el primer trimestre. Al nacimiento se evidencia diplejía facial, parálisis bilateral del VI par y pie equino varo. A los 17 días de vida presenta crisis tónico-clónicas y se diagnostica síndrome de Moebius y epilepsia de difícil control. Durante el seguimiento presenta retardo global del desarrollo, con predominio en el área del lenguaje y alteración de la deglución...(AU)

Moebius syndrome consists of congenital non-progressive facial nerve palsy and unilateral or bilateral paralysis of the sixth cranial nerve with inability to abduct the eye. The oculomotor cranial nerves, as well as, cranial nerves IX, X and XII, may also be affected. This syndrome has also been associated with anomalies of the musculoskeletal system and epilepsy. A case is presented in a preschool boy whose mother tried to voluntarily interrupt pregnancy in the first trimester but failed to abort. Facial diplegia, bilateral sixth cranial nerve palsy and bilateral equinovarus deformity of the feet were evidenced at birth. At 17 days of life he presented a tonic-clonic seizure and was diagnosed with Moebius syndrome and difficult to treat epilepsy. Delayed overall development, predominantly swallowing and speech difficulties, were evidenced upon follow up...(AU)

Homeless children: Experiences and meanings of the environments they construct / Los niños en situación de calle: experiencias y significados de los ambientes que construyen / As crianças em situação de rua: experiências e significados dos ambientes que constroem

Objective.This work sought to learn of the experiences of homeless children and understand the meanings they give to environments they construct within these spaces. The study took place in Medellín, Colombia in 2015. Methods. Ours was a qualitative research with ethnographic approach. Non-structured interviews and observations were conducted; a field diary was kept. Results. The street, although a space of public use, is converted by children into their private space; they carry in it almost all their activities and construct two big environments: that of the street that attracts and educates and that of the work that is transitory because it is performed to survive. These children dream with an ideal environment that allows them to live quietly. Conclusion. Children convert the street into a private place where they carry out their daily practices: socializing, working, sleeping, having fun, and relaxing, that is, a place of social construction.

Objetivo.Conocer las experiencias de los niños en situación de calle, y comprender los significados que dan a los ambientes que construyen en estos espacios. Medellín, Colombia 2015. Métodos. Investigación cualitativa con enfoque etnográfico. Se realizaron entrevistas no estructuradas, observaciones; se llevó un diario de campo. Resultados. La calle, aunque espacio de uso público, los niños la convierten en su espacio privado; desarrollan en ella casi la totalidad de sus actividades y construyen dos grandes ambientes: el de calle que engancha y educa y el de trabajo que es transitorio porque se hace para sobrevivir. Sueñan con un ambiente ideal que les permita vivir de manera tranquila. Conclusión. Los niños convierten la calle en un lugar privado donde realizan sus prácticas cotidianas: socializarse, trabajar, dormir, divertirse y relajarse, es decir, un lugar de construcción social.

Objetivo.Conhecer as experiências das crianças em situação de rua, e compreender os significados que dão aos ambientes que constroem nestes espaços. Medellín, Colômbia 2015. Métodos. Investigação qualitativa com enfoque etnográfico. Se realizaram entrevistas não estruturadas, observações; se fez um diário de campo. Resultados. A rua, embora espaço de uso público, as crianças a convertem em seu espaço privado; desenvolvem nela quase a totalidade de suas atividades e constroem dois grandes ambientes: o de rua que engancha e educa e o de trabalho que é transitório porque se faz para sobreviver. Sonham com um ambiente ideal que lhes permita viver de maneira tranquila. Conclusão. As crianças convertem a rua num lugar privado onde realizam suas práticas cotidianas: socializar-se, trabalhar, dormir, divertir-se e relaxar-se, ou seja, um lugar de construção social.

tert-Butanesulfinamides as Nitrogen Nucleophiles in Carbon-Nitrogen Bond Forming Reactions.

The use of tert-butanesulfinamides as nitrogen nucleophiles in carbon-nitrogen bond forming reactions is reviewed. This field has grown in the shadow of the general interest in N-tert-butanesulfinyl imines for asymmetric synthesis and occupies now an important place in its own right in the chemistry of the chiral amine reagent tert-butanesulfinamide. This article provides an overview of the area and emphasizes recent contributions wherein the tert-butanesulfinamides act as chiral auxiliaries or perform as nitrogen donors in metal-catalyzed amination reactions.

Homeless children: Experiences and meanings of the environments they construct.

OBJECTIVE: This work sought to learn of the experiences of homeless children and understand the meanings they give to environments they construct within these spaces. The study took place in Medellín, Colombia in 2015. METHODS: Ours was a qualitative research with ethnographic approach. Non-structured interviews and observations were conducted; a field diary was kept. RESULTS: The street, although a space of public use, is converted by children into their private space; they carry in it almost all their activities and construct two big environments: that of the street that attracts and educates and that of the work that is transitory because it is performed to survive. These children dream with an ideal environment that allows them to live quietly. CONCLUSION: Children convert the street into a private place where they carry out their daily practices: socializing, working, sleeping, having fun, and relaxing, that is, a place of social construction.

Uso de la Homeopatía Unicista en el tratamiento del trastorno ansioso depresivo / Use of Unicist Homeopathy in the treatment of anxious depressive disorder

El trastorno ansioso depresivo representa uno de los principales problemas de salud pública en la sociedad actual y uno de los principales motivos de consulta en atención primaria en salud. Se planteó una monografía que describe cual es el enfoque actual a nivel conceptual, de diagnóstico, de tratamiento y de pronóstico, tanto en la medicina convencional como en la homeopatía Unicista de dicho trastorno y posteriormente se realiza una revisión bibliográfica y en diferentes bases de datos acerca de su tratamiento homeopático actual. Se concluye que el manejo con Homeopatía Unicista del Trastorno Ansioso Depresivo es equiparable al tratamiento con medicina convencional e incluso en algunos estudios lo supera y representa para el paciente una alternativa con menos efectos secundarios adversos y que ofrece además una mejoría considerable en su calidad de vida.

[Tuberculosis of the breast]. / Mastitis tuberculosa.

We report a case of granulomatous mastitis caused by Mycobacterium tuberculosis in an immunocompetent woman with chronic inflammatory lesions of the breast. It was diagnosed by detection of mycobacteria DNA using polymerase chain reaction technique targeting IS6110 insertion element of M. tuberculosis complex in a paraffin-embedded histological specimen. The primary breast tuberculosis is rare, even in countries where the incidence and prevalence of pulmonary and extra pulmonary tuberculosis are high. It should be suspected in female patients with chronic granulomatous mastitis with no apparent cause. The cornerstone of treatment is antituberculous chemotherapy, and surgery is rarely required.

Mastitis tuberculosa / Tuberculosis of the breast

Se informa un caso de mastitis granulomatosa causada por Mycobacterium tuberculosis en una paciente inmunocompetente con lesiones inflamatorias crónicas de la mama, diagnosticada por la detección de ADN de la micobacteria mediante la técnica de reacción en cadena de la polimerasa de la secuencia de inserción IS6110 presente en el complejo M. tuberculosis , en una biopsia de mama embebida en parafina. La tuberculosis primaria de la mama es rara, incluso en países con alta prevalencia de tuberculosis, y debe sospecharse en pacientes con mastitis granulomatosa crónica de causa no clara. El pilar del tratamiento es la quimioterapia antituberculosa y, ocasionalmente, la cirugía.

We report a case of granulomatous mastitis caused by Mycobacterium tuberculosis in an immunocompetent woman with chronic inflammatory lesions of the breast. It was diagnosed by detection of mycobacteria DNA using polymerase chain reaction technique targeting IS6110 insertion element of M. tuberculosis complex in a paraffin-embedded histological specimen. The primary breast tuberculosis is rare, even in countries where the incidence and prevalence of pulmonary and extra pulmonary tuberculosis are high. It should be suspected in female patients with chronic granulomatous mastitis with no apparent cause. The cornerstone of treatment is antituberculous chemotherapy, and surgery is rarely required.

Identification of potential biomarkers to distinguish Mycobacterium colombiense from other mycobacterial species.

Mycobacterium avium complex (MAC) consists of 9 species of slow-growing mycobacteria with differing degrees of pathogenicity, host preference and environmental distribution. Mycobacterium colombiense is a novel member of MAC that is responsible for disseminated infections in HIV-infected patients in Colombia and lymphadenopathy cases in Europe. At present, methods to easily differentiate novel members of MAC are lacking. In this study, we identified possible biomarkers that are potentially useful for the detection of M. colombiense by PCR or chromatography. The Randomly Amplified Polymorphic DNA (RAPD) technique was used to amplify genomic fragments of M. colombiense CECT 3035 that were subsequently used in the development of a direct colony-specific PCR assay using specific primers. The designed primers amplified a 634-bp fragment of DNA from M. colombiense, which included a 450-bp genomic region that encodes a hypothetical protein of 149 amino acids that is exclusive to M. colombiense. Bioinformatic analyses revealed that this hypothetical protein had no signal peptide, active sites or functional domains to aid its identification or classification. In addition, using thin-layer chromatography, we identified a different profile of mycolates for M. colombiense strains. The test developed in this study has potential applications in the routine identification of M. colombiense and in molecular assays designed for the surveillance of MAC strains.

Neurofibromatosis de von Recklinghausen: presentación de un caso de neurofibroma vaginal y revisión de la literatura / von recklinghausen’s neurofibromatosis: presenting a case of vaginal neurofibroma and literature review

Objetivo: revisar las manifestaciones de la neurofibromatosis de presentación en la región genital, el diagnóstico diferencial y el manejo de las lesiones.Materiales y métodos: paciente de 63 años remitida por masa en región genital a la Unidad de Colposcopia y Patología del Tracto Genital Inferior del Hospital de Suba, institución pública de segundo nivel de complejidad ubicada en Bogotá, Colombia, donde se atiende a población del régimen subsidiado. Al examen físico se encontraron manchas café-au-lait y lesiones compatibles con neurofibromas que orientaron el diagnóstico de neurofibromatosis tipo 1. Se realizó una búsqueda sistemática de la literatura en Medline-Pubmed usando los términos MeSH neurofibromatosis, enfermedad de von Recklinghausen, vagina, tracto genital, tumor pélvico; se presenta el caso clínico y la revisión del tema.Resultados: se encontraron 7991 publicaciones relacionadas con neurofibromatosis, y de estas solo 30 relacionadas con lesiones pélvicas y de tracto genitourinario; solo 6 reportes de casos y una serie de casos presentaban lesiones localizadas en tracto genital inferior. Para la descripción de las generalidades y los criterios diagnósticos se seleccionaron 12 artículos de revisión del tema. El diagnóstico diferencial incluye schwannoma, neuroma, mixoma, leiomioma y pólipo fibroepitelial.Conclusiones: el hallazgo de neurofibromas en el tracto genitourinario es un evento de baja ocurrencia y es un tema de interés para ginecólogos, pediatras y urólogos pues constituye un reto diagnóstico.

Objective: Reviewing manifestations of neurofibromatosis presenting in the genital region, their differential diagnosis and managing lesions. Materials and methods: The case of a 63-year-old patient admitted to the Suba hospital’s colposcopy and pathology of the lower genital tract service due to having a mass in the genital region is presented; the hospital is a second level complexity public institution in Bogotá, Colombia, dealing with a subsidised regime population. Physical examination revealed café-au-lait spots and lesions compatible with neurofibroma, thereby orientating diagnosis towards neurofibromatosis type 1. A systematic search was made of the literature in Medline-Pubmed, using the MeSH terms: neurofibromatosis, von Recklinghausen’s disease, vagina, genital tract, pelvic tumour. A clinical case and review of the topic are presented. Results: 7,991 publications related to neurofibromatosis were found. Just 30 of them were related to pelvic lesions and the genitourinary tract and only 6 case reports and one case series dealt with lesions located in the lower genital tract; 12 articles reviewing the topic were selected for a description of the diagnostic generalities and criteria. Differential diagnosis included schwannoma, neuroma, myxoma, leiomyoma and fibroepithelial polyp. Conclusions: A neurofibroma being identified in the genitourinary tract is an infrequently occurring event, constituting a topic of interest for gynaecologists, paediatricians and urologists as it represents a diagnostic challenge.

A first insight on the population structure of Mycobacterium tuberculosis complex as studied by spoligotyping and MIRU-VNTRs in Bogotá, Colombia.

With an incidence of 25.6/100,000 in 2008, tuberculosis (TB) remains an important public health problem in Colombia. In this study, a total of 152 Mycobacterium tuberculosis complex strains isolated in Bogotá, Colombia between years 1995 and 2007 were genotyped by spoligotyping and 12-loci MIRU-VNTRs. The various spoligotyping-based genotypic lineages in our sample were: Latin American & Mediterranean (LAM) n=75, 49.34%; Haarlem, n=38, 25.0%; ill-defined T group, n=21, 13.82%; S family, n=5, 3.29%; X clade, n=2, 1.32%; Beijing, n=1, 0.65%, while strains with unknown signatures (n=10) represented 6.58% of isolates. Using spoligotyping as a first molecular marker and MIRU-VNTRs as second marker, we obtained 102 single patterns and 14 clustered patterns (n=52 strains from 49 patients, 2-8 strains per cluster). The MIRU-VNTRs patterns corresponded to 50 MITs for 109 strains and 43 orphan patterns. The most frequent patterns were MIT190 (n=12), MIT45 (n=10), and MIT25 (n=9). The Hunter & Gaston discriminatory index (HGDI) of both methodologies used together showed a value of 0.992. In our setting, the HGDI of five loci subset (MIRU10, 16, 23, 26 and 40) contributed most to the discriminatory power of 12-loci format used (HGDI=0.977). The lineage distribution of M. tuberculosis showed that more than 3/4 of strains in Bogotá are commonly found in Latin America, Caribbean, and Europe. This observation might reflect the shared post-Columbus history of Colombia and its Latin-American neighbors as well as strains brought in by 20th century immigrants from Europe. We also demonstrate the usefulness of MIRU-VNTR to detect suspected links among patients and polyclonal infections.

Westphalen's diol diacetate: 19(10→5)-abeo-5ß-cholest-9-ene-3ß,6ß-diyl diacetate.

THE STRUCTURE OF THE TITLE STEROID [ALTERNATIVE NAME: 3ß,6ß-diacet-oxy-5ß-methyl-19-norcholest-9(10)-ene], C31H50O4, confirms the generally accepted mechanism for the rearrangement of a cholestan-5α-ol derivative reported a century ago by Westphalen. The methyl group at position 10 of the starting material migrates to position 5 in the steroidal nucleus, while a Δ(9) bond is formed, as indicated by the C=C bond length of 1.347 (4) Å. The methyl transposition leaves the 5R configuration unchanged, with the methyl oriented towards the ß face. During the rearrangement, the steroidal B ring experiences a conformational distortion from chair to envelope with the C atom at position 6 as the flap. In the title structure, the isopropyl group of the side chain is disordered over two positions, with occupancies of 0.733 (10) and 0.267 (10). The carbonyl O atom in the acetyl group at C3 is also disordered with an occupancy ratio of 0.62 (4):0.38 (4).

First case of multidrug-resistant tuberculosis caused by a rare "Beijing-like" genotype of Mycobacterium tuberculosis in Bogotá, Colombia.

This report describes a first case due to a genetically distinct and relatively rare "Beijing-like" strain of Mycobacterium tuberculosis isolated from a 15 years old female patient who died shortly after the initiation of antituberculous therapy with second-line drugs. Positive cultures obtained from lung, kidney and adrenal glands upon autopsy were identified as Mycobacterium tuberculosis complex characterized by an identical 15-banded IS6110-RFLP pattern, and were found to be resistant to all the 4 first-line antituberculous drugs tested (rifampin, isoniazid, ethambutol and streptomycin). Spoligotyping followed by comparison with the SITVIT2 database revealed that the isolate belonged to a rare pattern identified as Spoligotype International Type SIT190, which represents only 1.7% of all the Beijing strains worldwide. We present data on its worldwide distribution and present an evolutionary scenario based on available MIRU typing data.

[Molecular epidemiology of tuberculosis in Bogotá in clinical isolates obtained over an 11-year period]. / Epidemiología Molecular de la Tuberculosis en Bogotá en Aislados Clínicos obtenidos durante 11 Años.

OBJECTIVE: Characterising clinical Mycobacterium tuberculosis isolates obtained from 1995 to 2006 in Bogotá , Colombia , using standardised IS6110-based RFLP typing for determining phylogenetic relationships. Calculating cases due to recent infection (grouped cases) cf endogenous reactivation (single patterns). METHODS: This retrospective study characterised 137 clinical Mycobacterium tuberculosis isolates obtained in Bogotá from 1995 to 2006. Study variables consisted of gender, age, HIV status, homelessness, Ziehl Neelsen smear result and date of culture. All isolates were freshly identified by phenotypic methods, confirmed by PRA and evaluated for susceptibility to antimicrobial agents according to the proportional method. Mycobacterium tuberculosis cultures were typed by standardised IS6110-based RFLP. RESULTS: All isolates were confirmed as being M. tuberculosis by phenotypic and genotypic methods. 9,4 % monoresistance and 2,9 % MDR (rifampicin- and isoniazid-resistant) were found. 129 M . tuberculosis isolates were genotyped; 96 (74 %) of them presented unique DNA fingerprints, whilst 35 (26 %) were grouped into 17 clusters consisting of two to four isolates. Direct epidemiological links between patients could not be established in most cases. Only HIV status was a significant predictor of clustering amongst the variables being studied (p<0.05). CONCLUSION: The results of our study revealed a high proportion of unique DNA fingerprints, suggesting high genetic variability between M. tuberculosis strains in Bogotá , Colombia , meaning that most cases of TB in this study were attributed to endogenous reactivation.

Epidemiología Molecular de la Tuberculosis en Bogotá en Aislados Clínicos obtenidos durante 11 Años / Molecular epidemiology of tuberculosis in Bogotá in clinical isolates obtained over an 11-year period

Objetivo: Tipificar molecularmente aislados clínicos de Mycobacterium tuberculosis obtenidas en Bogotá entre los años 1995 a 2006, mediante la técnica RFLP-IS6110 para establecer las relaciones filogenéticas existentes entre ellos y determinar casos debidos a infección reciente (casos agrupados) Vs reactivaciones endógenas (patrones únicos). Métodos: Se realizó un estudio retrospectivo, en el que se incluyeron 137 aislados clínicos pertenecientes al complejo Mycobacterium tuberculosis, obtenidos en Bogotá entre los años 1995 a 2006. Las variables estudiadas para cada paciente fueron: sexo, edad, confección con el Virus de la Inmunodeficiencia Humana , habitante en situación de calle, resultado de la baciloscopia, fecha del cultivo. Los aislados fueron identificados fenotípicamente y confirmados genotípicamente mediante el método molecular PRA y evaluados para sensibilidad a fármacos antituberculosos de primera línea utilizando el método simplificado de las proporciones múltiples. La genotipificación se realizó empleando el método de referencia RFLP-IS6110 (Polimorfismo en la Longitud de los Fragmentos de restricción). Resultados: Todos los aislados fueron confirmados como pertenecientes al complejo M. tuberculosis, mostrando la identificación fenotípica una concordancia del 100 por ciento con la identificación genotípica. La monorresistencia encontrada fue de 9,4 por ciento, y la MDR (resistencia a Rifampicina e Isoniazida) fue 2,9 por ciento. La genotipificación se realizó a 129 aislados, de los cuales 96 (74 por ciento) mostraron diferentes patrones RFLP-IS6110 y 35 aislados (26 por ciento) estuvieron agrupados en 17 clusters conformados por 2 a 4 aislados. La relación epidemiológica entre los pacientes no pudo ser establecida en la mayoría de los casos. De las variables estudiadas solamente el estado de coinfección con VIH fue un predictor significativo para el agrupamiento (p<0.05). Conclusión: Los resultados de nuestro estudio muestran un alto porcentaje de genotipos con patrones RFLP-IS6110 únicos, lo que sugiere gran variabilidad genética entre los aislados de M. tuberculosis circulantes en Bogotá, indicando que la mayoría de los casos de tuberculosis en el estudio pueden ser atribuibles a reactivaciones endógenas.

Objective: Characterising clinical Mycobacterium tuberculosis isolates obtained from 1995 to 2006 in Bogotá , Colombia , using standardised IS6110-based RFLP typing for determining phylogenetic relationships. Calculating cases due to recent infection (grouped cases) cf endogenous reactivation (single patterns). Methods: This retrospective study characterised 137 clinical Mycobacterium tuberculosis isolates obtained in Bogotß from 1995 to 2006. Study variables consisted of gender, age, HIV status, homelessness, Ziehl Neelsen smear result and date of culture. All isolates were freshly identified by phenotypic methods, confirmed by PRA and evaluated for susceptibility to antimicrobial agents according to the proportional method. Mycobacterium tuberculosis cultures were typed by standardised IS6110-based RFLP. Results: All isolates were confirmed as being M. tuberculosis by phenotypic and genotypic methods. 9,4 percent monoresistance and 2,9 percent MDR (rifampicin- and isoniazid-resistant) were found. 129 M . tuberculosis isolates were genotyped; 96 (74 percent) of them presented unique DNA fingerprints, whilst 35 (26 percent) were grouped into 17 clusters consisting of two to four isolates. Direct epidemiological links between patients could not be established in most cases. Only HIV status was a significant predictor of clustering amongst the variables being studied (p<0.05). Conclusion: The results of our study revealed a high proportion of unique DNA fingerprints, suggesting high genetic variability between M. tuberculosis strains in Bogotß , Colombia , meaning that most cases of TB in this study were attributed to endogenous reactivation.

Long-lasting effects of a Bacillus thuringiensis serovar israelensis experimental tablet formulation for Aedes aegypti (Diptera: Culicidae) control.

Dengue is a growing public health problem in many tropical and subtropical countries worldwide. At present, the only method of controlling or preventing the disease is to eliminate its vector, Aedes aegypti (L.) (Diptera: Culicidae). In the current study, an experimental larvicide tablet formulation XL-47 based on Bacillus thuringiensis serovar israelensis (Bti) and containing 4.8% of technical powder was developed. This formulation was evaluated against Ae. aegypti in three different sets of experiments, under field-simulated conditions: two experiments were indoors and under partial sunlight exposure and one experiment was outdoors with sunlight exposure. Larvae were added throughout the experiment two times per week, and the residual larvicidal activity was recorded daily. Pupal formation was reduced in the containers with Bti by > 80% in relation to the containers without treatment for 12 wk; to our knowledge, this is the longest period of control reported for a Bti tablet formulation outdoors under sunlight exposure. Moreover, samples from the top, middle, and bottom of the water column were collected to perform bacterial plate counts and toxicity assays. The Bti population and the active ingredient of the tablet formulation remained mainly at the bottom of the containers and mosquito larvae reached the formulation by diving and shredding the tablet's material. In conclusion, the experimental tablet formulation XL-47 showed an inhibition of pupal formation that lasted for long periods under sunlight exposure.