Detection of kinase domain mutations in BCR::ABL1 leukemia by ultra-deep sequencing of genomic DNA.

The screening of the BCR::ABL1 kinase domain (KD) mutation has become a routine analysis in case of warning/failure for chronic myeloid leukemia (CML) and B-cell precursor acute lymphoblastic leukemia (ALL) Philadelphia (Ph)-positive patients. In this study, we present a novel DNA-based next-generation sequencing (NGS) methodology for KD ABL1 mutation detection and monitoring with a 1.0E-4 sensitivity. This approach was validated with a well-stablished RNA-based nested NGS method. The correlation of both techniques for the quantification of ABL1 mutations was high (Pearson r = 0.858, p < 0.001), offering DNA-DeepNGS a sensitivity of 92% and specificity of 82%. The clinical impact was studied in a cohort of 129 patients (n = 67 for CML and n = 62 for B-ALL patients). A total of 162 samples (n = 86 CML and n = 76 B-ALL) were studied. Of them, 27 out of 86 harbored mutations (6 in warning and 21 in failure) for CML, and 13 out of 76 (2 diagnostic and 11 relapse samples) did in B-ALL patients. In addition, in four cases were detected mutation despite BCR::ABL1 < 1%. In conclusion, we were able to detect KD ABL1 mutations with a 1.0E-4 sensitivity by NGS using DNA as starting material even in patients with low levels of disease.

Local, solvation pressures and conformational changes in ethylenediamine aqueous solutions probed using Raman spectroscopy.

Raman spectra of 1,2-ethylenediamine (EDA) in aqueous solutions are used to demonstrate that EDA molecules experience an anti-gauche conformational change resulting from the interactions with water. The observed Raman shift reveals a compressive (hydrophobic) effect of water on both methylene and amino groups of EDA. Raman spectra of EDA at high pressures are used as reference to quantify the intermolecular EDA-H2O interactions in terms of local pressures. These results are compared with macroscopic solvation pressures calculated from the cohesive energy parameter. We compare and discuss all our observations with available computational and experimental studies.

Fecal Carriage of Extended-Spectrum ß-Lactamases in Healthy Humans, Poultry, and Wild Birds in León, Nicaragua-A Shared Pool of blaCTX-M Genes and Possible Interspecies Clonal Spread of Extended-Spectrum ß-Lactamases-Producing Escherichia coli.

Antibiotic-resistant bacteria are a major concern in the healthcare of today, especially the increasing number of gram-negative bacteria producing ß-lactamases such as extended-spectrum ß-lactamases (ESBLs). However, little is known about the relationship of ESBL producers in humans and domestic and wild birds, especially in a low-income setting. Therefore, we studied the fecal carriage of ESBL-producing Escherichia coli and Klebsiella pneumoniae in healthy humans, poultry, and wild birds in the vicinity of León, Nicaragua. Three hundred fecal samples were collected during December 2012 from humans (n = 100), poultry (n = 100) and wild birds (n = 100). The samples were examined for ESBL-producing E. coli and K. pneumoniae, revealing the prevalence of 27% in humans, 13% in poultry, and 8% in wild birds. Further characterization of the ESBL-producing isolates was performed through polymerase chain reaction (PCR) (NDM, CTX-M), epidemiological typing (ERIC2-PCR), multilocus sequence typing, and sequencing. ESBL producers harbored blaCTX-M-2, blaCTX-M-15, blaCTX-M-22, and blaCTX-M-3 genotypes. The blaCTX-M-15 constituted the absolute majority of ESBL genes among all samples. ERIC-PCR demonstrated highly related E. coli clones among humans, poultry, and wild birds. Clinically relevant E. coli clone ST648 was found in humans and poultry. There is a shared pool of blaCTX-M genes between humans and domesticated and wild birds in Nicaragua, and the results suggest shared clones of ESBL-producing E. coli. The study adds to the notion that wild birds and poultry can pick up antibiotic-resistant bacteria of human origin and function as a melting pot of resistance. Structured surveillance programs of antimicrobial resistance and a more regulated prescription of antibiotics are warranted in Nicaragua.

Local hydration pressures in methanol aqueous solution: a Raman spectroscopy analysis.

Raman spectra of methanol-water mixtures were measured over the whole composition range at room conditions. The spectra are used to quantify the strength of intermolecular interactions in terms of local internal pressures. The conclusions derived from the spectroscopic analysis are discussed within the framework of the solvation pressure model using values of the cohesion energy density expected in the mixture. This work demonstrates that an appropriate analysis of Raman spectroscopy experiments can be used to quantify the local internal pressures due to intermolecular interactions in liquid mixtures, provided that high pressure results of the pure liquids are available.

Community diarrhea incidence before and after rotavirus vaccine introduction in Nicaragua.

We estimated the incidence of watery diarrhea in the community before and after introduction of the pentavalent rotavirus vaccine in León, Nicaragua. A random sample of households was selected before and after rotavirus vaccine introduction. All children < 5 years of age in selected households were eligible for inclusion. Children were followed every 2 weeks for watery diarrhea episodes. The incidence rate was estimated as numbers of episodes per 100 child-years of exposure time. A mixed effects Poisson regression model was fit to compare incidence rates in the pre-vaccine and vaccine periods. The pre-vaccine cohort (N = 726) experienced 36 episodes per 100 child-years, and the vaccine cohort (N = 826) experienced 25 episodes per 100 child-years. The adjusted incidence rate ratio was 0.60 (95% confidence interval [CI] 0.40, 0.91) during the vaccine period versus the pre-vaccine period, indicating a lower incidence of watery diarrhea in the community during the vaccine period.

Irritable bowel syndrome and gastrointestinal parasite infection in a developing nation environment.

Postinfectious IBS is defined in the industrialized world as IBS onset following a sentinel gastrointestinal infection. In developing nations, where repeated bacterial and parasitic gastrointestinal infections are common, the IBS pathophysiology may be altered. Our aim was to investigate the relationship between intestinal parasite infection and IBS in the "nonsterile" developing world environment. IBS subjects were identified from a population-based sample of 1624 participants using the Rome II Modular Questionnaire. Stool samples from cases and randomly selected controls were examined for ova and parasites. Logistic regression models explored the relationship between IBS and parasite infection. The overall IBS prevalence among participants was 13.2% (9.3% males, 15.9% females). There was no difference in parasite carriage between IBS cases and controls, 16.6% versus 15.4% (P = 0.78), nor among IBS subtypes. The pathophysiology of post-infectious IBS may be altered in the developing world as compared to industrialized nations and warrants investigation.

Frecuencia de portadores nasales de Staphylococcus aureus resistente a meticilina en personal de salud de hospitales de Nicaragua / Frequency of nasal carriers of methicillin-resistant Staphylococcus aureus among health workers in Nicaraguan hospitals

Objetivo. Conocer la frecuencia de portadores nasales de cepas de Staphylococcus aureus resistentes a meticilina (SARM) y el patrón de resistencia antimicrobiana de esas cepas obtenidas de trabajadores de la salud de cuatro hospitales de Nicaragua. Métodos. Se realizó un estudio descriptivo, transversal, en el período del 1 de junio de 2009 al 30 de septiembre de 2010. Los hisopados nasales de los trabajadores de la salud que aceptaron voluntariamente participar en el estudio fueron cultivados en medio agar base de detección de resistencia a oxacilina (ORSAB). La identificación de los aislados de S. aureus se realizó por métodos cotidianos y la resistencia a meticilina se determinó por la presencia del gen mecA con la técnica de reacción en cadena de polimerasa. El patrón de resistencia antimicrobiana se detectó por difusión en disco. Cada participante firmó un consentimiento informado con anterioridad a la toma de la muestra. Resultados. Participaron en el estudio 569 trabajadores de la salud, de los cuales 208 eran del hospital de León, 155 de dos hospitales de Chinandega y 206 del de Managua. La frecuencia de portadores nasales de SARM fue de 9,6% en León, 11,6% en Chinandega y 6,7% en Managua. El perfil de resistencia de las cepas SARM fue similar en los cuatro hospitales y todas las cepas fueron sensibles a vancomicina. Del total de cepas SARM aisladas, 15% fueron multirresistentes. El porcentaje de resistencia a eritromicina fue el más alto, seguido del de clindamicina. Conclusiones. Los resultados del estudio se pueden considerar una advertencia sobre la circulación de cepas SARM entre el personal de salud de los hospitales participantes y aportan información relevante en relación al perfil de resistencia de las cepas SARM.

Objective. To determine the frequency of nasal carriers of strains of methicillinresistant Staphylococcus aureus (MRSA) and the antimicrobial resistance pattern of these strains, obtained from health workers from four hospitals in Nicaragua. Methods. A descriptive cross-sectional study was conducted between 1 June 2009 and 30 September 2010. Nasal swabs were taken from health workers who voluntarily agreed to participate in the study, and were cultured on an oxacillin-resistant screening agar base (ORSAB) medium. The S. aureus isolates were identified using ordinary methods, and methicillin resistance was confirmed based on the presence of the mecA gene using the polymerase chain reaction technique. The antimicrobial resistance pattern was detected by the disk diffusion method. Each participant signed an informed consent form before the samples were taken. Results. A total of 569 health workers participated in the study: 208 from one hospital in León, 155 from two hospitals in Chinandega, and 206 from one hospital in Managua. The frequency of nasal MRSA carriers was 9.6% in León, 11.6% in Chinandega, and 6.7% in Managua. The MRSA resistance profile was similar in the four hospitals, and all the strains were sensitive to vancomycin. Of the total MRSA strains isolated, 15% were multi-drug resistant. Erythromycin had the highest percentage of resistance, followed by clindamycin. Conclusions. The results of the study may be regarded as a warning that MRSA strains are circulating among health workers in the participating hospitals. The study also contributes important information regarding the resistance profile of MRSA strains.

[Frequency of nasal carriers of methicillin-resistant Staphylococcus aureus among health workers in Nicaraguan hospitals]. / Frecuencia de portadores nasales de Staphylococcus aureus resistente a meticilina en personal de salud de hospitales de Nicaragua.

OBJECTIVE: To determine the frequency of nasal carriers of strains of methicillin-resistant Staphylococcus aureus (MRSA) and the antimicrobial resistance pattern of these strains, obtained from health workers from four hospitals in Nicaragua. METHODS: A descriptive cross-sectional study was conducted between 1 June 2009 and 30 September 2010. Nasal swabs were taken from health workers who voluntarily agreed to participate in the study, and were cultured on an oxacillin-resistant screening agar base (ORSAB) medium. The S. aureus isolates were identified using ordinary methods, and methicillin resistance was confirmed based on the presence of the mecA gene using the polymerase chain reaction technique. The antimicrobial resistance pattern was detected by the disk diffusion method. Each participant signed an informed consent form before the samples were taken. RESULTS: A total of 569 health workers participated in the study: 208 from one hospital in León, 155 from two hospitals in Chinandega, and 206 from one hospital in Managua. The frequency of nasal MRSA carriers was 9.6% in León, 11.6% in Chinandega, and 6.7% in Managua. The MRSA resistance profile was similar in the four hospitals, and all the strains were sensitive to vancomycin. Of the total MRSA strains isolated, 15% were multi-drug resistant. Erythromycin had the highest percentage of resistance, followed by clindamycin. CONCLUSIONS: The results of the study may be regarded as a warning that MRSA strains are circulating among health workers in the participating hospitals. The study also contributes important information regarding the resistance profile of MRSA strains.

Prevalence of rheumatic heart disease in children and young adults in Nicaragua.

Rheumatic heart disease (RHD) results in morbidity and mortality that is disproportionate among individuals in developing countries compared to those living in economically developed countries. The global burden of disease is uncertain because most previous studies to determine the prevalence of RHD in children relied on clinical screening criteria that lacked the sensitivity to detect most cases. The present study was performed to determine the prevalence of RHD in children and young adults in León, Nicaragua, an area previously thought to have a high prevalence of RHD. This was an observational study of 3,150 children aged 5 to 15 years and 489 adults aged 20 to 35 years randomly selected from urban and rural areas of León. Cardiopulmonary examinations and Doppler echocardiographic studies were performed on all subjects. Doppler echocardiographic diagnosis of RHD was based on predefined consensus criteria that were developed by a working group of the World Health Organization and the National Institutes of Health. The overall prevalence of RHD in children was 48 in 1,000 (95% confidence interval 35 in 1,000 to 60 in 1,000). The prevalence in urban children was 34 in 1,000, and in rural children it was 80 in 1,000. Using more stringent Doppler echocardiographic criteria designed to diagnose definite RHD in adults, the prevalence was 22 in 1,000 (95% confidence interval 8 in 1,000 to 37 in 1,000). In conclusion, the prevalence of RHD among children and adults in this economically disadvantaged population far exceeds previously predicted rates. The findings underscore the potential health and economic burden of acute rheumatic fever and RHD and support the need for more effective measures of prevention, which may include safe, effective, and affordable vaccines to prevent the streptococcal infections that trigger the disease.

Ecological aspects of antimicrobial susceptibility of anaerobic bacteria in Nicaragua

El objetivo de este estudio fue conocer el perfil de sensibilidad de bacterias anaerobias aisladas de la microflora intestinal de niños sanos no tratados con antimicrobiana desde su nacimiento o al cumplir 1,3, 6, 12, y 24 meses de edad y de niños tratados conlos antimicrobianos comúnmente usados en Nicaragua yde las mismas edades. 947 cepas de Bacteroides y 745cepas de Clostridium fueron aisladas de 67 niños sanos y 94 niños tratados con antimicrobianas. Las concentraciones mínimas inhibitorias de ampicilina, cefoxitina, imipenem, clindamicina, metronidazol y cloranfenicol fueron determinadas por el método de dilución en agar. La producción de batalactamasas, se determinó mediante el análisis con nitrocefina. No se encontraron bacterias resistentes a imipenem, clindamicina, metronidazol y cloranfenicol. Las especies de bacteroides aisladas de los niños tratadas con antimicrobianos mostraron un progresivo descenso de la sensibilidad a ampicilina y cefoxitina valores del 88 porciento a 78 porciento y 94 porciento a 81 porciento desde el primer mes hasta los 24 meses de edad. Todas la cepas de bacteroides aísladas de los niños sanos<- doce meses de edad fueron 100 porciento sensibles a cefoxitina y 92 porciento sensibles en los mayores de edad. las sensibilidad de bacteroides para ampicilina fue desde el 91 porciento al mes de edad hasta el 86 porciento a los 24 meses de edad. Todas las cepas de clostridium fueron sensibles a cefoxitina y ampicilina. La producción de betalactamasas fue positiva solamente en cepas de bacteroides. Los resultados de este estudio indican que es necesario un uso racional de los antimicrobianos para evitar el desarrollo de resistencias en las bacterias anaerobías