Biological puzzles solved by using Streptococcus pneumoniae: a historical review of the pneumococcal studies that have impacted medicine and shaped molecular bacteriology.

The major human pathogen Streptococcus pneumoniae has been the subject of intensive clinical and basic scientific study for over 140 years. In multiple instances, these efforts have resulted in major breakthroughs in our understanding of basic biological principles as well as fundamental tenets of bacterial pathogenesis, immunology, vaccinology, and genetics. Discoveries made with S. pneumoniae have led to multiple major public health victories that have saved the lives of millions. Studies on S. pneumoniae continue today, where this bacterium is being used to dissect the impact of the host on disease processes, as a powerful cell biology model, and to better understand the consequence of human actions on commensal bacteria at the population level. Herein we review the major findings, i.e., puzzle pieces, made with S. pneumoniae and how, over the years, they have come together to shape our understanding of this bacterium's biology and the practice of medicine and modern molecular biology.

Development and evaluation of an artificial intelligence for bacterial growth monitoring in clinical bacteriology.

In clinical bacteriology laboratories, reading and processing of sterile plates remain a significant part of the routine workload (30%-40% of the plates). Here, an algorithm was developed for bacterial growth detection starting with any type of specimens and using the most common media in bacteriology. The growth prediction performance of the algorithm for automatic processing of sterile plates was evaluated not only at 18-24 h and 48 h but also at earlier timepoints toward the development of an early growth monitoring system. A total of 3,844 plates inoculated with representative clinical specimens were used. The plates were imaged 15 times, and two different microbiologists read the images randomly and independently, creating 99,944 human ground truths. The algorithm was able, at 48 h, to discriminate growth from no growth with a sensitivity of 99.80% (five false-negative [FN] plates out of 3,844) and a specificity of 91.97%. At 24 h, sensitivity and specificity reached 99.08% and 93.37%, respectively. Interestingly, during human truth reading, growth was reported as early as 4 h, while at 6 h, half of the positive plates were already showing some growth. In this context, automated early growth monitoring in case of normally sterile samples is envisioned to provide added value to the microbiologists, enabling them to prioritize reading and to communicate early detection of bacterial growth to the clinicians.

Un padre olvidado de la Microbiología: Louis Joblot / A forgotten father of Microbiology

El microscopista francés Louis Joblot (1645-1723), contemporáneo de Antoine van Leeuwenhoek y Robert Hooke, puede ser considerado uno de los padres de la protistología/microbiología. Su obra titulada "Descripciones y usos de varios microscopios nuevos" de 1718 contiene varias extraordinarias imágenes de protozoos en movimiento y en división binaria. Lamentablemente, algunas imágenes de dicha obra contenían figuras fantásticas, por lo que su legado fue rápidamente obscurecido. Sus experimentos sobre el fenómeno de generación espontánea marcaron un hito en el desarrollo de este debate y se adelantaron en casi siglo y medio a los experimentos de Louis Pasteur.

The French microscopist Louis Joblot (1645-1723), a contemporary of Antoine van Leeuwenhoek and Robert Hooke, he can be considered one of the fathers of protistology/microbiology. His work entitled "Descriptions and uses of various new microscopes" of 1718 contains several extraordinary images of protozoa in motion and in binary division. Unfortunately, some images of this work contained fantastic figures, so his legacy was quickly obscured. His experiments on the phenomenon of spontaneous generation marked a milestone in the development of this debate and anticipated Louis Pasteur's experiments by almost a century and a half.

Landfill bacteriology: Role in waste bioprocessing elevated landfill gaseselimination and heat management.

This study delves into the critical role of microbial ecosystems in landfills, which are pivotal for handling municipal solid waste (MSW). Within these landfills, a complex interplay of several microorganisms (aerobic/anaerobic bacteria, archaea or methanotrophs), drives the conversion of complex substrates into simplified compounds and complete mineralization into the water, inorganic salts, and gases, including biofuel methane gas. These landfills have dominant biotic and abiotic environments where various bacterial, archaeal, and fungal groups evolve and interact to decompose substrate by enabling hydrolytic, fermentative, and methanogenic processes. Each landfill consists of diverse bio-geochemical environments with complex microbial populations, ranging from deeply underground anaerobic methanogenic systems to near-surface aerobic systems. These kinds of landfill generate leachates which in turn emerged as a significant risk to the surrounding because generated leachates are rich in toxic organic/inorganic components, heavy metals, minerals, ammonia and xenobiotics. In addition to this, microbial communities in a landfill ecosystem could not be accurately identified using lab microbial-culturing methods alone because most of the landfill's microorganisms cannot grow on a culture medium. Due to these reasons, research on landfills microbiome has flourished which has been characterized by a change from a culture-dependent approach to a more sophisticated use of molecular techniques like Sanger Sequencing and Next-Generation Sequencing (NGS). These sequencing techniques have completely revolutionized the identification and analysis of these diverse microbial communities. This review underscores the significance of microbial functions in waste decomposition, gas management, and heat control in landfills. It further explores how modern sequencing technologies have transformed our approach to studying these complex ecosystems, offering deeper insights into their taxonomic composition and functionality.

Does Topical Vancomycin Powder Use in Fracture Surgery Change Bacteriology and Antibiotic Susceptibilities? An Analysis of the VANCO Trial.

OBJECTIVE: To determine whether intrawound vancomycin changes the bacteriology of surgical site infection pathogens and investigate the emergence of antibiotic-resistant pathogens. DESIGN: Secondary analysis of phase III, prospective, randomized clinical trial. SETTING: Thirty-six US trauma centers. PATIENT SELECTION CRITERIA: Patients who became infected after fixation of tibial plateau or pilon fracture. OUTCOME MEASURES AND COMPARISONS: Pathogen types and bacterial susceptibilities as determined from routine clinical culture in the operating room. RESULTS: Seventy-four patients were studied who were 67.5% male with a mean age of 48.6 years. A lower proportion of gram-positive cocci was observed in the vancomycin powder compared with the standard-of-care group (3.7% vs. 8.0%, P = 0.01). Methicillin-resistant Staphylococcus aureus infection incidence was comparable in both the vancomycin powder and the standard-of-care groups, but rates of methicillin-susceptible S. aureus infections were lower in the treatment group (1.4% vs. 4.8%, P = 0.01). The incidence of coagulase-negative Staphylococci and gram-negative rod infections were similar in both groups. There was no significant difference in susceptibilities between groups in rates of vancomycin-resistant enterococcus. CONCLUSIONS: Topical vancomycin powder decreases the likelihood of gram-positive infections consistent with the biologic activity of vancomycin. Fewer methicillin-susceptible S. aureus and coagulase-negative Staphylococci infections were observed in the group treated with vancomycin powder. An effect of vancomycin powder on methicillin-resistant S. aureus infection risk was not detected given the low incidence in both the intrawound vancomycin and the standard-of-care groups. There was no emergence of gram-negative rod infections or increased resistance patterns observed. Use of topical vancomycin powder does not seem to produce infections in these patients with greater antibiotic resistance than would have occurred without its use. LEVEL OF EVIDENCE: Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence.

Veterinary bacteriology in Denmark from the 1880s to 2022.

This paper gives an account of the history of veterinary bacteriology including clinical veterinary bacteriology as well as the area of veterinary public health in Denmark from the 1880s to 2022. We describe key persons, including B. Bang, C.O. Jensen, K.A. Jensen and others who made important contributions to the development of these areas of microbiological expertise, and we discuss how challenges ranging from bovine tuberculosis to bacterial antimicrobial resistance have been met. Further, we describe progress in research on important bacterial pathogens both with regard to animal clinical aspects and zoonotic food-related aspects. Finally, we describe current issues in relation to One Health and research organization.

El Instituto de Higiene y la enseñanza de la Bacteriología en Chile / The Institute of Hygiene and the teaching of Microbiology in Chile

El Instituto de Higiene, fundado por el gobierno de Chile en 1892, aparte de sus funciones en el ámbito de la salud pública, participó activamente en la docencia de pregrado de Bacteriología de la Escuela de Medicina de la Universidad de Chile. La cátedra de Bacteriología fundada en 1895 fue trasladada en 1902 a la sección de seroterapia de dicho instituto (uno de los cinco edificios que formaban el instituto). La cátedra permaneció en ese lugar por tres décadas, siendo trasladada en 1930 por el Dr. Hugo Vaccaro de vuelta a la Escuela de Medicina. Por otra parte, la cátedra extraordinaria de Bacteriología siguió ligada a dicho instituto y a su inmediato sucesor el Instituto Bacteriológico de Chile. Sin embargo, luego del incendio de la Escuela de Medicina en 1948, la cátedra ordinaria tuvo que retornar a sus antiguos edificios en la ribera del Mapocho y paralelamente la cátedra extraordinaria se trasladó a una nueva ubicación en Ñuñoa.

The Institute of Hygiene, founded by the Chilean government in 1892, apart from its functions in the field of public health, actively participated in the undergraduate teaching of Bacteriology at the School of Medicine of the University of Chile. The chair of Bacteriology founded in 1895 was transferred in 1902 to the serotherapy section of the mentioned institute (one of the five buildings that made up the institute). The chair remained in that place for three decades, being transferred by Dr. Hugo Vaccaro back to the School of Medicine in 1930. On the other hand, the Extraordinary Chair of Bacteriology continued to be linked to the said institute and to its immediate successor, the Bacteriological Institute of Chile. However, after the fire at the School of Medicine in 1948, the ordinary chair had to return to its old buildings on the banks of the Mapocho and at the same time the extraordinary chair moved to a new location in Ñuñoa.

Los inicios de la fagoterapia en Chile: los doctores Mercedes Perez Matus y Hugo Vaccaro Kosovich / The beginnings of phage therapy in Chile: the doctors Mercedes Perez Matus and Hugo Vaccaro Kosovich

Mercedes Pérez Matus y Hugo Vaccaro Kosovich fueron destacados médicos y microbiólogos de la cátedra ordinaria de Bacteriología de la Facultad de Medicina de la Universidad de Chile. En 1931, ambos médicos fueron contratados por la Facultad de Medicina para reorganizar la convulsionada Cátedra de Bacteriología luego de la crisis política de 1931. En el mismo período el destacado investigador del instituto Pasteur Eugéne Wollman vino a Chile a dirigir el Instituto Sanitas (1929-1931), incorporando en nuestro país el conocimiento sobre los bacteriófagos y las técnicas para su aislamiento. La prolongada labor docente y de investigación de Vaccaro y Pérez se extendió por casi 40 años (1931-1970). Publicaron numerosos artículos científicos, siendo uno de sus temas preferidos, en los primeros años, el estudio de los bacteriófagos que aprendieron junto a Wollman. En la década de los 40, bajo el liderazgo de los Dres. Vaccaro y Pérez, se inició la fagoterapia en Chile.

Mercedes Perez Matus and Hugo Vaccaro Kosovich were distinguished doctors and microbiologists from the ordinary chair of Bacteriology at the Faculty of Medicine of the University of Chile. In 1931, both doctors were hired by the F aculty of Medicine to reorganize the convulsed Chair of Bacteriology after the political crisis of 1931. In the same period, the prominent Pasteur Institute researcher Eugene Wollman came to Chile to direct the Sanitas Institute (1929-1931), incorporating in our country the knowledge about bacteriophages and the techniques for their isolation. The long teaching and research work of Vaccaro and Pérez spanned almost 40 years (1931-1970). They published numerous scientific articles, being one of their favorite topics, in the early years, the study of bacteriophages that they learned together with Wollman. In the 1940s, under the leadership of Drs. Vaccaro and Pérez, phage therapy began in Chile.

Producción de vacunas en el antiguo Instituto Bacteriológico de Chile / Vaccine production at the ancient Bacteriological Institute of Chile

Se relata el nacimiento, auge y decadencia, de la producción de vacunas en el antiguo Instituto Bacteriológico de Chile, desde su fundación en 1929 hasta su fin en 1980, por boca de quien fuera por diecisiete años primero encargado de la fabricación de vacunas bacterianas y luego director de la institución. Las vicisitudes de la vacuna BCG, la introducción del toxoide tetánico, el fin de la vacuna antivariólica y el triunfo de vacuna antirrábica de Fuenzalida y Palacios, se narran a menudo con comentarios de quienes participaron en estos hechos.

The birth, rise and decline, of vaccine production at the Bacteriological Institute of Chile is recounted by mouth of who was for seventeen years first in charge of manufacturing and then director of the institution. The vicissitudes of the BCG vaccine, the introduction of tetanus toxoid, the end of smallpox vaccine, and the triumph of the rabies vaccine are often related with comments from those who participated in the events.

Cultivo primario de Helicobacter pylori a partir de biopsias gástricas obtenidas por endoscopia / Primary culture of Helicobacter pylori from endoscopic gastric biopsies

Objetivo: Determinar la viabilidad del cultivo de la bacteria Helicobacter pylori en Costa Rica por medio de la documentación de toma de muestras, la comparación del diagnóstico histopatológico y la descripción de los diagnósticos asociados a los aislamientos obtenidos con los resultados de la ureasa rápida. Métodos: Investigación descriptiva que involucró a pacientes de entre los 35 y 70 años, de ambos sexos, que asistieron al Servicio de Endoscopia Digestiva del Hospital Clínica Bíblica entre febrero y junio del 2019 para estudio gastroscópico. Se obtuvieron biopsias gástricas para diagnóstico histopatológico, prueba de ureasa rápida y cultivo de Helicobacter pylori. Para este último, se transportaron las biopsias en un medio de transporte semisólido, se maceró el tejido y se cultivó enagar Skirrow y agar selectivo para Helicobacter; una placa de cada medio se incubó a 37 °C en microaerofilia entre 48 horas y 10 días. La positividad del cultivo se realizó por observación de la morfología colonial y la bacteria se identificó por análisis microscópico al fresco, tinción de Gram y pruebas bioquímicas (catalasa, ureasa y oxidasa). Resultados: Se incluyó a 44 pacientes (edad: 50.6 ± 10.0, 54.5% masculinos). Se recuperó Helicobacter pylori en biopsias de 27 pacientes (61.4% de éxito). La recuperación de la bacteria fue similar en el medio Skirrow y en el selectivo para Helicobacter. El porcentaje de éxito de recuperación semanal aumentó durante el estudio hasta alcanzar un éxito del 100% en la semana 11. Se comparó el cultivo con la ureasa rápida en 27 pacientes y la concordancia entre ambos métodos fue de un coeficiente kappa de Cohen de 0.48. El cultivo detectó la bacteria en un 56% de los pacientes, la ureasa rápida en un 37% y la combinación de ambas técnicas permitió la detección en un 60%. El diagnóstico endoscópico más frecuente en los pacientes con cultivo positivo fue la gastritis eritematosa y gastritis crónica superficial y el diagnóstico histopatológico predominante fue gastritis crónica con atrofia gástrica. El diagnóstico por cultivo coincidió con la detección por azul de toluidina en un 80.4% de los casos. Conclusiones: Se puede implementar el cultivo de Helicobacter pylori en Costa Rica. Este estudio tuvo un porcentaje de recuperación de la bacteria de 61.4%. La combinación del método de cultivo con la prueba de ureasa rápida y la detección histológica contribuye a un diagnóstico certero y oportuno. Recomendamos que, con base en protocolos descritos en esta investigación, cada laboratorio estandarice las condiciones que le permitan un buen porcentaje de recuperación y una implementación adaptada a sus actividades de rutina.

Aim: To document the recent experiences on the implementation of sampling and culturing Helicobacter pylori in Costa Rica, to compare it with other diagnostic methods: rapid urease test and histopathology and to describe the diagnoses associated with the obtained isolates. Methods: Descriptive research involving patients who visited the digestive endoscopy department of the Clínica Bíblica hospital in San José, Costa Rica between February and July of 2019 for gastroscopy. Gastric biopsies were obtained and histopathological analysis, rapid urease test, and bacteriological culture for Helicobacter pylori were performed. For culture techniques, the sample was transported in an in-house semi-solid medium. Biopsy fragments were macerated and plated on Skirrow agar and Helicobacterselective in-house agar, and incubated in microaerophilic atmosphere for 48 hours to 10 days. Culture positivity was determined by observation of the colonial morphology and microscopic observation; Gram staining and biochemical tests (urease, catalase, and oxidase) were used for bacterial identification. Results: 44 patients (mean aged 50.6 ± 10.0 years old, 54.5% male) were included in the study. Helicobacter pylori was recovered in biopsies from 27 patients (61.4% success rate). Bacterial growth was similar regardless the culture medium, but the physiological state of the bacteria was better in the Helicobacter-selective agar than in Skirrow. The weekly recovery rate increased to reach a 100% recovery plateau on week 11. Culture was compared with the rapid urease test in 27 patients, and the concordance between both methods using Cohen's kappa coefficient was 0.48. Whilst the culture detected Helicobacter pylori in 56% of the patients, and the rapid urease test in 37%, the combination of both allowed a 60% rate. The most frequent endoscopic diagnosis in patients with positive cultures were erythematous gastritis and chronic superficial gastritis, and the predominant histopathological diagnosis was chronic atrophic gastritis. Culture-based diagnosis was consistent with the histopathology detection of Helicobacter pylori in 80.4% of the cases. Conclusions: The implementation of H. pylori culture in Costa Rica is possible. This study had a 61.4% recovery rate. The combination of culture with rapid urease test and histopathology increases the probability of an accurate and timely diagnosis. We recommend that, based on previously described protocols such as ours, each laboratory adjusts the conditions to allow a good recovery rate and implement H. pylori diagnostic methods most suitable to their routine activities.

From Dresden to the world: images of the German Hygiene Museum's relations with Latin America, 1911-1933 / De Dresden para o mundo: imagens das relações do Museu Alemão de Higiene com a América Latina, 1911-1933

Abstract As of the nineteenth century, the number of world fairs and hygiene exhibitions grew significantly. This phenomenon was linked to the experience of modernity and the emergence of bacteriology, when different cities were sanitized with the aim of combating urban diseases and epidemics. For the purpose of sanitary education and hygiene propaganda, many objects and pictures were displayed in hygiene exhibitions and museums, such as the International Hygiene Exhibition of 1911 and the German Hygiene Museum, both in Dresden. The goal of this article is to analyze a chapter of the international history of health through images that portray the connections between the German Hygiene Museum and Latin American countries between 1911 and 1933.

Resumo A partir do século XIX, o número de exposições universais e de exposições de higiene cresceu significativamente. Esse fenômeno estava ligado à experiência da modernidade e ao surgimento da bacteriologia, quando diferentes cidades foram higienizadas com o objetivo de combater doenças e epidemias urbanas. Visando à educação sanitária e à propaganda da higiene, inúmeros objetos e imagens foram exibidos em exposições e museus de higiene, como na Exposição Internacional de Higiene de 1911 e no Museu Alemão de Higiene, ambos em Dresden. O objetivo deste artigo é analisar um capítulo da história internacional da saúde por meio de imagens que retratam as conexões entre o Museu Alemão de Higiene e os países latino-americanos de 1911 a 1933.

Triunfo de Finlay, una obra para el proceso formativo de profesionales de la salud / Triumph of Finlay, one picture useful for preparation the professionals of the health

Un acontecimiento en la vida del doctor Carlos Juan Finlay Barrés motivó al Maestro Esteban Valderrama Peña a realizar la composición pictórica Triunfo de Finlay. La pintura representa al médico cubano exponiendo ante una comisión médica militar estadounidense, su teoría sobre el modo de contagio de la fiebre amarilla y el ente transmisor, el mosquito Aedes aegypti. Finlay había estudiado durante años la enfermedad sin que las autoridades coloniales reconocieran los resultados de sus investigaciones, a pesar de que la enfermedad causaba estragos en los militares españoles y la población. En 1898 la intervención norteamericana en la guerra de los cubanos contra el colonialismo español, generó la necesidad de sanear la Isla y crear condiciones higiénicas favorables para la estancia de las tropas norteñas. El general y médico Leonard Wood fijó su atención en la teoría de Finlay y solicitó al gobierno de su país especialistas para verificarla. Fue enviada una comisión dirigida por el mayor Walter Reed, cirujano del ejército y catedrático de bacteriología de la Facultad de Medicina Militar en Washington, para confirmarla. En la pintura, el artista representó la reunión de Finlay con la comisión norteña. El presente trabajo destaca la trascendencia de la obra, su valor estético y la integración del arte, la historia, la medicina y la ciencia. Se propone incluir su estudio como parte del trabajo educativo dirigido a fomentar la cultura general en la formación de los profesionales de la salud(AU)

One event for Doctor Carlos J. Finlay Barrés was the motive for the oil painting composition named "Triumph of Finlay" by Master of Art Esteban Valderrama Peña. The picture shows Finlay presenting his theory about the transmission of yellow fever by mosquitoes to the US Army Yellow Fever Commission. He had conceived a new infection way able to explain the propagation of the illness, and added the possibility of their scientific confirmation by experimental method. In 1898 the US army took place in the Cuban`s fighting against the Spanish colonialism. This circumstance beginning the need to improve the sanitary condition in the Island to create favorable hygienic conditions to the stay of the troops. The Military Governor of the Island, general and physician Leonard Wood took Finlay´s theory as center of his attention. He requested the government of his country experts to verify it. One commission heading for Major Walter Reed was sent. Reed was a surgeon of the army and professor of bacteriology in Military Medicine Faculty in Washington. After experimentally investigation, the commission could confirm Finlay´s theory. Valderrama´s picture shows the meeting of Finlay with the experts. This article has like objective to give emphasis about this pictorial by its importance for the Cuba´s medicine and the science history in Cuba. By the esthetic value that contains it must be included in the educational labor towards the preparation the professionals of the health. It is useful for contributing with the general culture integrating art, history, medicine and science(AU)

Pediatría y cultura de viaje: los pensionados españoles y la apropiación del laboratorio en la periferia, 1907-1939 / Pediatrics and travel culture: Spanish travel award-holders and the appropriation of laboratories on the periphery, 1907-1939

Resumen Partiendo de la hipótesis de que el laboratorio jugó un papel importante en la autonomía disciplinar de la pediatría, este artículo estudia la influencia del viaje científico en la apropiación de nuevas metodologías por parte de los pediatras y puericultores españoles del primer tercio del siglo XX. Para ello, se analizan las pensiones concedidas a tal efecto por la Junta para Ampliación de Estudios e Investigaciones Científicas. Se describe la geografía científica creada por el programa y se profundiza en el papel de los mentores - especialmente de Gustavo Pittaluga (1876-1956) - en este proceso. Además de un estudio prosopográfico del grupo, se presentan tres casos que demuestran la importancia del programa en el encuentro de la pediatría con la bacteriología, la anatomía patológica y la bioquímica.

Abstract Starting from the hypothesis that laboratories played an important role in pediatrics becoming an autonomous discipline, this article studies the influence of scientific travel on the appropriation of new methodologies by Spanish pediatricians and child-care experts in the first third of the twentieth century. To do so, it analyzes the travel awards granted by the Junta para Ampliación de Estudios e Investigaciones Científicas. It describes the scientific geography created by the program and takes an in-depth look at the role of mentors - especially Gustavo Pittaluga (1876-1956) - in this process. In addition to a prosopographical study of the group, it presents three cases that demonstrate the importance of the program in bringing pediatrics into contact with bacteriology, pathological anatomy and biochemistry.

Juan Nicolás Dávalos Betancourt y Federico Grande Rossi: dos amigos y una profesión / Juan Nicolás Dávalos Betancourt y Federico Grande Rossi: two friends, one profession

El papel desempeñado por destacados científicos cubanos y matanceros como Juan Nicolás Dávalos Betancourt y Federico Grande Rossi fue fundamental en el desarrollo de la bacteriología en el país. Con este trabajo se pretende acercar a estos dos hombres unidos en la vida como grandes amigos y en la profesión. Juan Nicolás Dávalos Betancourt conocido como "el sabio que soñaba con las bacterias" trasciende su campo de trabajo particular y se proyecta en el desarrollo de nuestra nación. Federico Grande Rossi fue médico bacteriólogo y fecundo escritor (AU).

The role played by eminent Cuban and Matanzasan scientist like Juan Nicolas Davalos Betancourt and Federico Grandi Rossi was essential for the development of the bacteriology in the country. With this work the authors pretend to bring near these two men who were very close in life as friends and colleagues in their profession. Juan Nicolas Davalos Betancourt, known as "the scholar who dreamed with bacteria" went beyond his particular work field and entered the process of development of Cuban nation. Federico Grandi Rossi was a doctor-bacteriologist and a prolific writer (AU).

Primer reporte de escherichia coli productora de toxina shiga no O157 que codifica el gen de la enterohemolisina en carne cruda en colombia / First report of Shiga toxin-producing escherichia coli non-O157 that encodes the enterohemolysin gene in raw beef in colombia

Dentro de los patotipos de Escherichia coli, el grupo STEC puede producir en el ser humano desde diarrea hemorrágica hasta insuficiencia renal aguda e incluso la muerte; el ganado bovino es el principal reservorio de este agente patógeno y por ende la ingestión de alimentos derivados de estos animales de abasto son una fuente muy importante de infección para el hombre. El objetivo principal de este estudio fue determinar la prevalencia de STEC en muestras de carne cruda comercializada en Pamplona-Colombia y en cepas obtenidas a partir de las muestras. Se analizaron cien muestras de carne cruda aplicando la técnica de Reacción en Cadena de la Polimerasa para la detección de los siguientes genes en muestras y en cepas STEC: stx1, stx2, eae y hlyA. Adicionalmente, se estableció el patrón de resistencia-susceptibilidad antibiótica de cepas STEC aisladas empleando métodos regulados. En el 39% de las muestras fue posible detectar el gen stx2; en el 38%, de ellas, se detectaron los genes stx1 y stx2. Además, se aislaron cepas STEC en el 13% de las muestras analizadas, 85% de ellas portaban el gen hlyA. No se detectó la presencia del gen eae o del serogrupo O157. Las cepas aisladas demostraron resistencia frente a algunos antibióticos de primera y segunda generación. En conclusión, se detectó la presencia de genes que codifican factores de virulencia en las muestras de carne analizadas que representan un riesgo potencial para la salud de los consumidores. Este es el primer reporte de STEC no O157 que codifica el gen de la enterohemolisina en alimentos en Colombia(AU)

Within the Escherichia coli patotypes, the STEC group can produce in humans from hemorrhagic diarrhea to acute renal failure and even death; cattle are the main reservoir of this pathogen and therefore the ingestion of food derived from these stock animals are a very important source of infection for man. The main objective of this study was to determine the prevalence of STEC in raw meat samples marketed in Pamplona-Colombia and in strains obtained from those samples. One hundred raw meat samples were analyzed using the Polymerase Chain Reaction technique for the detection of the following genes in samples and in STEC strains: stx1, stx2, eae and hlyA. In addition, STEC strains were isolated in 13% of the analyzed samples, 85% of them carried the hlyA gene. The presence of the eae gene or serogroup O157 was not detected. The isolated strains demonstrated resistance against some first and second generation antibiotics. In conclusion, the presence of genes encoding virulence factors in the meat samples analyzed, that represent a potential health risk factor to consumers, was confirmed. This is the first report of STEC non-O157 that encodes the enterohemolysin gene in foods in Colombia(AU)