Identification of the long polar fimbriae gene variants in the locus of enterocyte effacement-negative Shiga toxin-producing Escherichia coli strains isolated from humans and cattle in Argentina

The long polar fimbriae (Lpf) is one of few adhesive factors of Shiga toxin-producing Escherichia coli (STEC) and it is associated with colonization of the intestine. Studies have demonstrated the presence of lpf genes in several pathogenic E. coli strains, and classification of variants based on polymorphisms in the lpfA1 and lpfA2 genes has been adopted. Using a collection of Argentinean locus of enterocyte effacement (LEE)-negative STEC strains, we determined that the different lpfA types were present in a wide variety of serotypes with no apparent association between the types of lpfA1 or lpfA2 genes and the severity of human disease. The lpfA2-1 was the most prevalent variant identified, which was present in 95.8% of the isolates, and lpfA1-3 and lpfA2-2, proposed as specific biomarkers of E. coli O157:H7, were not found in any of the serotypes studied. The prevalence of lpf genes in a large number of strains is useful to understand the genetic diversity of LEE-negative STEC and to define the association of some of these isolates carrying specific lpf-variants with disease.Fil: Galli, Lucía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico CONICET- La Plata. Instituto de Genética Veterinaria "Ing. Fernando Noel Dulout". Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Instituto de Genética Veterinaria; Argentina. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud “Dr. C. G. Malbrán”; ArgentinaFil: Torres, Alfredo G.. University of Texas Medical Branch; Estados UnidosFil: Rivas, Marta. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud “Dr. C. G. Malbrán”; Argentin

Identification of the Long Polar Fimbriae gene variants in Locus of Enterocyte Effacement-negative Shiga toxin-producing Escherichia coli strains isolated from humans and cattle in Argentina

The long polar fimbriae (Lpf) is one of few adhesive factors of Shiga toxin-producing Escherichia coli (STEC) and it is associated with colonization of the intestine. Studies have demonstrated the presence of lpf genes in several pathogenic E. coli strains, and classification of variants based on polymorphisms in the lpfA1 and lpfA2 genes has been adopted. Using a collection of Argentinean locus of enterocyte effacement (LEE)-negative STEC strains, we determined that the different lpfA types were present in a wide variety of serotypes with no apparent association between the types of lpfA1 or lpfA2 genes and the severity of human disease. The lpfA2-1 was the most prevalent variant identified, which was present in 95.8% of the isolates, and lpfA1-3 and lpfA2-2, proposed as specific biomarkers of E. coli O157:H7, were not found in any of the serotypes studied. The prevalence of lpf genes in a large number of strains is useful to understand the genetic diversity of LEE-negative STEC and to define the association of some of these isolates carrying specific lpf-variants with disease.Instituto de Genética Veterinari

Identification of the Long Polar Fimbriae gene variants in Locus of Enterocyte Effacement-negative Shiga toxin-producing Escherichia coli strains isolated from humans and cattle in Argentina

The long polar fimbriae (Lpf) is one of few adhesive factors of Shiga toxin-producing Escherichia coli (STEC) and it is associated with colonization of the intestine. Studies have demonstrated the presence of lpf genes in several pathogenic E. coli strains, and classification of variants based on polymorphisms in the lpfA1 and lpfA2 genes has been adopted. Using a collection of Argentinean locus of enterocyte effacement (LEE)-negative STEC strains, we determined that the different lpfA types were present in a wide variety of serotypes with no apparent association between the types of lpfA1 or lpfA2 genes and the severity of human disease. The lpfA2-1 was the most prevalent variant identified, which was present in 95.8% of the isolates, and lpfA1-3 and lpfA2-2, proposed as specific biomarkers of E. coli O157:H7, were not found in any of the serotypes studied. The prevalence of lpf genes in a large number of strains is useful to understand the genetic diversity of LEE-negative STEC and to define the association of some of these isolates carrying specific lpf-variants with disease.Instituto de Genética Veterinari

Comparison of the in vitro and in vivo susceptibilities of Burkholderia mallei to Ceftazidime and Levofloxacin

<p>Abstract</p> <p>Background</p> <p><it>Burkholderia mallei </it>is a zoonotic Gram negative bacterium which primarily infects solipeds but can cause lethal disease in humans if left untreated. The effect of two antibiotics with different modes of action on <it>Burkholderia mallei </it>strain ATCC23344 was investigated by using <it>in vitro </it>and <it>in vivo </it>studies.</p> <p>Results</p> <p>Determination of minimal inhibitory concentrations (MICs) <it>in vitro </it>was done by the agar diffusion method and the dilution method. The MICs of levofloxacin and ceftazidime were in the similar range, 2.5 and 5.0 μg/ml, respectively. Intracellular susceptibility of the bacterium to these two antibiotics in J774A.1 mouse macrophages <it>in vitro </it>was also investigated. Macrophages treated with antibiotics demonstrated uptake of the drugs and reduced bacterial loads <it>in vitro</it>. The efficacy of ceftazidime and levofloxacin were studied in BALB/c mice as post-exposure treatment following intranasal <it>B. mallei </it>infection. Intranasal infection with 5 × 10⁵CFUs of <it>B. mallei </it>resulted in 90% death in non-treated control mice. Antibiotic treatments 10 days post-infection proved to be effective <it>in vivo </it>with all antibiotic treated mice surviving to day 34 post-infection. The antibiotics did not result in complete clearance of the bacterial infection and presence of the bacteria was found in lungs and spleens of the survivors, although bacterial burden recovered from levofloxacin treated animals appeared reduced compared to ceftazidime.</p> <p>Conclusion</p> <p>Both antibiotics demonstrated utility for the treatment of glanders, including the ability for intracellular penetration and clearance of organisms <it>in vitro</it>.</p

Interstitial lung disease: silicosis, a case report

A 51-year-old male had dry cough and chest pain for more than 10 years. He has a history of exposure to biomass. He worked as supervisor of tunnel construction. Twelve years ago he had hemoptysis, for which he received anti-tuberculosis therapy despite not having smear-positive. The physical examination was normal except that fine crackles were found in both bases. He had an obstructive pattern in spirometry. And, there was great interstitial involvement in the lung parenchyma in tomography studies. A biopsy was performed by video thoracoscopy, which confirmed the diagnosis of silicosis

Development of a Multiplex PCR Assay for Detection of Shiga Toxin-Producing Escherichia coli, Enterohemorrhagic E. coli, and Enteropathogenic E. coli Strains

Escherichia coli O157:H7 and other pathogenic E.coli strains are enteric pathogens associated with food safety threats and which remaina significant cause of morbidity and mortality worldwide. In the current study, we investigated whether enterohemorrhagic E. coli (EHEC), Shiga toxin-producing E. coli (STEC), and enteropathogenic E. coli (EPEC) strains can be rapidly and specifically differentiated with multiplex PCR (mPCR) utilizing selected biomarkers associated with each strains respective virulence genotype. Primers were designed to amplify multiple intimin (eae) and long polar fimbriae (lpfA) variants, the bundle forming pilus gene bfpA, and the Shiga toxin encoding genes stx1 and stx2. We demonstrated consistent amplification of genes specific to the prototype EHEC O157:H7 EDL933 (lpfA1-3, lpfA2-2, stx1, stx2, and eae-gama) and EPEC O127:H6 E2348/69 (eae-alfa, lpfA1-1, and bfpA) strains using the optimized mPCR protocol with purified genomic DNA (gDNA). A screen of gDNA from isolates in a diarrheagenic E. coli collection revealed that the mPCR assay was successful in predicting the correct pathotype of EPEC and EHEC clones grouped in the distinctive phyogenetic disease clusters EPEC1 and EHEC1, and was able to differentiate EHEC1 from EHEC2 clusters. The assay detection threshold was 2×104 CFU per PCR reaction for EHEC and EPEC. mPCR was also used to screen Argentinean clinical samples from hemolytic uremic syndrome and diarrheal patients, resultingin 91 % sensitivity and 84% specificity when compared to established molecular diagnostic procedures. In conclusion, our mPCR methodology permitted differentiation of EPEC, STEC and EHEC strains from other pathogenic E.coli; therefore, the assay becomes an additional tool for rapid diagnosis of these organisms.Instituto de Genética Veterinari

Mejoría de valores VEF1 porcentuales en EPOC atribuida a ejercicios respiratorios en casa. Reporte de un caso.

Paciente varón de 73 años, peruano de nacimiento, de ascendencia japonesa, con diagnóstico de enfermedad pulmonar obstructiva crónica (EPOC), y antecedente de haber fumado 47 paquetes año, que, en seguimiento de 6,7 años presenta mejoría en los valores del volumen espiratorio forzado en el primer segundo porcentual (VEF1 %) sostenidamente. La mejoría es atribuida a ejercicios respiratorios diarios realizados por el paciente en su casa, además del uso de la medicación para EPOC

Protective Antigens Against Glanders Identified by Expression Library Immunization

Burkholderia are highly evolved Gram-negative bacteria that primarily infect solipeds but are transmitted to humans by ingestion and cutaneous or aerosol exposures. Heightened concern over human infections of Burkholderia mallei and the very closely related species B. pseudomallei is due to the pathogens’ proven effectiveness as bioweapons, and to the increased potential for natural opportunistic infections in the growing diabetic and immuno-compromised populations. These Burkholderia species are nearly impervious to antibiotic treatments and no vaccine exists. In this study, the genome of the highly virulent B. mallei ATCC23344 strain was examined by expression library immunization for gene-encoded protective antigens. This protocol for genomic-scale functional screening was customized to accommodate the unusually large complexity of Burkholderia, and yielded 12 new putative vaccine candidates. Five of the candidates were individually tested as protein immunogens and three were found to confer significant partial protection against a lethal pulmonary infection in a murine model of disease. Determinations of peripheral blood cytokine and chemokine profiles following individual protein immunizations show that interleukin-2 (IL-2) and IL-4 are elicited by the three confirmed candidates, but unexpectedly interferon-γ and tumor necrosis factor-α are not. We suggest that these pathogen components, discovered using genetic immunization and confirmed in a conventional protein format, will be useful toward the development of a safe and effective glanders vaccine