Simulación de la propagación de un brote por Acinetobacter baumannii en entornos hospitalarios / Simulation of an outbreak of Acinetobacter baumannii in hospitals

Introducción. Las infecciones por Acinetobacter baumannii se han convertido en un hecho habitual y preocupante en los ambientes hospitalarios. Consecuentemente son de especial importancia aquellas aplicaciones que permitan no sólo simular la aparición y propagación de un brote, sino también evaluar las posibles medidas de control. El desarrollo de modelos matemáticos juega un papel decisivo en esta tarea. Material y métodos. Se desarrolló un modelo matemático determinista basado en ecuaciones diferenciales ordinarias, cuyas variables y parámetros fueron identificados a partir del conocimiento de la epidemiología y de las características de A. baumannii. Dicho modelo fue analizado cualitativamente e implementado computacionalmente. Resultados. La implementación computacional del modelo teórico posibilitó obtener múltiples simulaciones a partir de diferentes condiciones iniciales. El análisis cualitativo de las mismas permitió definir de manera explícita las medidas de control más efectivas a la hora de controlar esta infección nosocomial. Conclusiones. La herramienta desarrollada es de gran utilidad en la gestión (predicción del comportamiento y evaluación de contramedidas profilácticas) de brotes por A. baumannii. Se demuestra de manera teórica la eficacia de medidas higiénicas y de cribado (AU)

Introduction. Acinetobacter baumannii infections have increased over time becoming a significant issue. Consequently, those applications that allow to predict the evolution of an outbreak and the relevance of the different control methods, are very important. The design of mathematical models plays a central role in this topic. Material and methods. Development of a deterministic mathematical model based on ordinary differential equations whose variables and parameters are defined upon the basis of knowledge of the epidemiology and characteristics of A. baumannii. This model is analyzed from a qualitative point of view and, also, its computational implementation is derived. Results. Several simulations were obtained developed from different initial conditions. The qualitative analysis of these simulations provides formal evidence of most effective control measures. Conclusions. The implementation of the computational model is an extremely useful tool in terms of managing A. baumannii outbreaks. There is mathematical proof of the fact that the observance of efficient hygiene and screening rules reduces the number of infected patients (AU)

Comparative study of bacterial translocation control with nitric oxide donors and COX2 inhibitor / Estudio comparativo del control de la translocación bacteriana con donadores de óxido nítrico e inhibidor de la COX2

OBJECTIVE AND DESIGN: To evaluate the beneficial effects of exogenous NO and an inhibitor of the COX2, and their action levels in a model of SIRS/bacterial translocation (BT) induced by Zymosan A®. MATERIAL AND METHODS: Ninety Wistar rats were submitted to different treatments, and after 12h and 24h they were anaesthetized in order to collect blood, mesenteric lymph nodes, and kidney for subsequent biochemical analyses and microbiological examinations. Treatments. A nitric oxide donor, Molsidomine®, was compared with a COX2 inhibitor, Celecoxib®. METHODS: Zymosan A® was administered to Wistar rats. The animals were divided into 6 groups: one group for survival study, Group (1) No manipulation (BASAL); Group (2) vehicle of Zymosan A® given intraperitoneally (SHAM); Group I (control), with Zymosan A® (0.6g/kg) intraperitoneally; Group II (Molsidomine), with Molsidomine® (4mg/kg) through the penis dorsal vein, 30min prior to administration of the Zy® (0.6g/kg); Group III (Celecoxib), with Celecoxib® (400mg/kg) orally through a stomach tube, 6h prior to administration of the Zy (0.6g/kg). Determinations. The parameters survival, bacterial translocation, renal function, neutrophil accumulation, oxygen free radicals (OFR), detoxifying enzymes, and cytokines were measured at different times after Zymosan administration. RESULTS: The model established induced a mortality rate of 100% and generated BT and systemic inflammatory response syndrome (SIRS) in all samples. It also significantly increased all variables, with p<.001 for MPO and all pro-inflammatory cytokines, and p<.01 for all OFR. Treatment with Molsidomine reduced mortality to 0%, decreased BT, MPO, pro-inflammatory cytokines and OFR (p<.001) significantly and increased IL-10 and IL-6 production. Moreover, the Celecoxib® showed a lower capacity for SIRS regulation. CONCLUSIONS: The exogenous administration of NO prevented BT and controlled SIRS. Therefore these results suggest that Molsidomine could be used as a therapeutic strategy to protect against BT

OBJETIVO Y DISEÑO. Evaluar los efectos beneficiosos del ON exógeno y de un inhibidor de la COX2 y sus niveles de acción en un modelo de síndrome de respuesta inflamatoria sistémica (SIRS)/traslocación bacteriana (TB) inducida por Zymosan A®. MATERIALES Y MÉTODOS: Noventa ratas Wistar fueron sometidas a diferentes tratamientos, y después de 12 y 24 horas fueron anestesiadas para recoger sangre, nódulos linfáticos mesentéricos y tejido renal, para analizarlos bioquímica y microbiológicamente. Tratamientos. Un donador de óxido nítrico, Molsidomina®, fue comparado con Celecoxib®, inhibidor de la COX2. MÉTODOS: Se administró Zymosan A® a las ratas Wistar. Estas fueron divididas en CINCO grupos: grupo 1 (basal), sin manipulaciones; grupo 2 (sham), vehículo de Zymosan A® administrado intraperitonealmente; grupo I (control), con Zymosan A® (0,6 g/kg) intraperitoneal; grupo II (Molsidomina) con Molsidomina® (4 mg/kg) administrada a través de la vena dorsal del pene, 30 minutos antes de la administración de Zymosan® (0,6 g/kg); y grupo III (Celecoxib) con Celecoxib® (400 mg/kg) administrado oralmente por tubo esomacal, 6 horas antes de la administración de Zymosan A® (0,6 g/kg). Determinaciones. Se midieron los parámetros supervivencia, traslocación bacteriana, función renal, acumulación de neutrófilos, radicales libres de oxígeno, enzimas detoxificantes y citoquinas, a diferentes tiempos después de la administración de Zymosan®. RESULTADOS: El modelo establecido inducía una tasa de mortalidad del 100%, y se generaba traslocación bacteriana y síndrome de respuesta inflamatoria sistémica en todas las muestras. También se incrementaban significativamente todas las variables, con p < 0,001 para mieloperoxidasa y todas las citokinas proinflamatorias, y p < 0,01 para todos los radicales libres de oxígeno. El tratamiento con Molsidomina reducía la mortalidad al 0%, disminuía la traslocación bacteriana, mieloperoxidasas, citokinas proinflamatorias y radicales libres de oxígeno (p < 0,001), e incrementaba la producción de IL-10 e IL-6. Además, Celecoxib® mostró una menor capacidad para la regulación del síndrome de respuesta inflamatoria sistémica. CONCLUSIONES: La administración exógena de óxido nítrico evita la traslocación bacteriana y controla el síndrome de respuesta inflamatoria sistémica. Estos resultados sugieren que Molsidomina podría usarse como estrategia terapéutica frente a la traslocación bacteriana

El microbiólogo clínico ante los cambios taxonómicos en el género Clostridium / The clinical microbiologist before the taxonomic changes in the genus Clostridium

Las especies incluidas en el género Clostridium son muy heterogéneas, tanto que desde un punto de vista fenotípico como filogenético. Los avances en la taxonomía polifásica y en particular en la filogenia están permitiendo resolver esta disfunción reclasificando a numerosas especies en otros géneros, aunque aún resta trabajo por hacer. Los cambios en las denominaciones genéricas son algo normal en taxonomía pero puede convertirse en un problema cuando afectan a especies con gran impacto clínico conocidas desde hace muchos años como es el caso de algunas especies tradicionales del género Clostridium. Tras conocerlos los microbiólogos clínicos, en cuyo quehacer la taxonomía es fundamental, deben valorar que está antes, la comunicación con los profesionales de la salud o la filogenia y valorar que quizás haya posibilidades de combinar ambos hechos. Este artículo revisa alguno de los cambios taxonómicos acaecidos en especies conocidas del género Clostridium, que genéticamente no pertenecen a este género, que pueden tener interés en clínica y evalúa, en lo posible, su trascendencia en la comunicación científica y sanitaria (AU)

The various species included in the genus Clostridium are very heterogeneous, both from a phenotypic and a phylogenetic point of view. The advances in polyphasic taxonomy, particularly in phylogeny, are allowing to resolve this dysfunction reclassifying several species in other genres, although there is still work to be done. Changes in generic denominations are quite normal in taxonomy, but can turn into a problem when they affect species with strong clinical impact and that have been recognised for a long time, as in the case of some traditional Clostridium species. After knowing these changes clinical microbiologists, in whose work taxonomy is an essential tool, should evaluate what matters most, if the communication with other health professionals or the phylogeny, and think about the possibility of combining both things. This paper reviews some of the taxonomic changes that have took place in well-known Clostridium species that can be clinically interesting and evaluates, as far as possible, their significance in the scientific and medical communication (AU)

Comparative study of bacterial translocation control with nitric oxide donors and COX2 inhibitor.

OBJECTIVE AND DESIGN: To evaluate the beneficial effects of exogenous NO and an inhibitor of the COX2, and their action levels in a model of SIRS/bacterial translocation (BT) induced by Zymosan A(®). MATERIAL AND METHODS: Ninety Wistar rats were submitted to different treatments, and after 12h and 24h they were anaesthetized in order to collect blood, mesenteric lymph nodes, and kidney for subsequent biochemical analyses and microbiological examinations. TREATMENTS: A nitric oxide donor, Molsidomine(®), was compared with a COX2 inhibitor, Celecoxib(®). METHODS: Zymosan A(®) was administered to Wistar rats. The animals were divided into 6 groups: one group for survival study, Group (1) No manipulation (BASAL); Group (2) vehicle of Zymosan A(®) given intraperitoneally (SHAM); Group I (control), with Zymosan A(®) (0.6g/kg) intraperitoneally; Group II (Molsidomine), with Molsidomine(®) (4mg/kg) through the penis dorsal vein, 30min prior to administration of the Zy(®) (0.6g/kg); Group III (Celecoxib), with Celecoxib(®) (400mg/kg) orally through a stomach tube, 6h prior to administration of the Zy (0.6g/kg). DETERMINATIONS: The parameters survival, bacterial translocation, renal function, neutrophil accumulation, oxygen free radicals (OFR), detoxifying enzymes, and cytokines were measured at different times after Zymosan administration. RESULTS: The model established induced a mortality rate of 100% and generated BT and systemic inflammatory response syndrome (SIRS) in all samples. It also significantly increased all variables, with p<.001 for MPO and all pro-inflammatory cytokines, and p<.01 for all OFR. Treatment with Molsidomine reduced mortality to 0%, decreased BT, MPO, pro-inflammatory cytokines and OFR (p<.001) significantly and increased IL-10 and IL-6 production. Moreover, the Celecoxib(®) showed a lower capacity for SIRS regulation. CONCLUSIONS: The exogenous administration of NO prevented BT and controlled SIRS. Therefore these results suggest that Molsidomine could be used as a therapeutic strategy to protect against BT.

[Noma/Cancrum oris: a neglected disease]. / La enfermedad de Noma/cancrum oris: una enfermedad olvidada.

Noma is an aggressive orofacial gangrenous pathology that damages hard and soft tissues of the mouth and the face. Throughout the centuries it has been present around the globe, but nowadays it has practically disappeared from developed countries and mainly affects children from the most disadvantaged places, especially in Africa. Noma disease is a multifactorial process; malnutrition, debilitating diseases (bacterial or viral systemic diseases, HIV-associated immunosuppression, etc.) and intraoral infections are some of the factors implied. The characteristic tissue necrosis is produced by a polymicrobial infection. Fusobacterium necrophorum, Prevotella intermedia, Prevotella melaninogenica, Fusobacterium nucleatum, Bacteroides fragilis, Bacillus cereus, Trueperella pyogenes, spyrochetes, etc, are some of the species that have been isolated from the affected areas. Without treatment, noma is lethal in a short period of time, and the patients that survive show severe sequelae that hinder their life and interpersonal relationships. The aim of this paper is to unify the existing information and to promote wider knowledge and awareness among the population.

La enfermedad de Noma/cancrum oris: una enfermedad olvidada / Noma/Cancrum oris: a neglected disease

La enfermedad de Noma es una patología gangrenosa agresiva orofacial que daña a tejidos duros y blandos de la boca y de la cara. A lo largo de los siglos ha estado presente en todo el planeta, aunque en la actualidad ha desaparecido prácticamente de los países desarrollados, afectando casi siempre a niños de los lugares más desfavorecidos, especialmente en el continente africano. Es un proceso multifactorial en el que intervienen factores como la malnutrición, las enfermedades debilitantes (infecciones sistémicas bacterianas o víricas, inmunodepresión asociada al VIH, etc.) y las infecciones intraorales. La necrosis tisular característica la origina una infección polimicrobiana. Algunas de las especies que se han aislado de las zonas afectadas son: Fusobacterium necrophorum, Prevotella intermedia, Prevotella melaninogenica, Fusobacterium nucleatum, Bacteroides fragilis, Bacillus cereus, Trueperella pyogenes, espiroquetas, etc. Sin tratamiento es letal en poco tiempo, y los pacientes que sobreviven presentan graves secuelas que dificultan su vida y sus relaciones interpersonales. El objetivo de esta revisión es unificar la información existente y promover un mayor conocimiento y concienciación de la población (AU)

Noma is an aggressive orofacial gangrenous pathology that damages hard and soft tissues of the mouth and the face. Throughout the centuries it has been present around the globe, but nowadays it has practically disappeared from developed countries and mainly affects children from the most disadvantaged places, especially in Africa. Noma disease is a multifactorial process; malnutrition, debilitating diseases (bacterial or viral systemic diseases, HIV-associated immunosuppression, etc.) and intraoral infections are some of the factors implied. The characteristic tissue necrosis is produced by a polymicrobial infection. Fusobacterium necrophorum, Prevotella intermedia, Prevotella melaninogenica, Fusobacterium nucleatum, Bacteroides fragilis, Bacillus cereus, Trueperella pyogenes, spyrochetes, etc, are some of the species that have been isolated from the affected areas. Without treatment, noma is lethal in a short period of time, and the patients that survive show severe sequelae that hinder their life and interpersonal relationships. The aim of this paper is to unify the existing information and to promote wider knowledge and awareness among the population (AU)