Molecular and epidemiologic characterization of the diphtheria outbreak in Venezuela.

In 2016, Venezuela faced a large diphtheria outbreak that extended until 2019. Nasopharyngeal or oropharyngeal samples were prospectively collected from 51 suspected cases and retrospective data from 348 clinical records was retrieved from 14 hospitals between November 2017 and November 2018. Confirmed pathogenic Corynebactrium isolates were biotyped. Multilocus Sequence Typing (MLST) was performed followed by next-generation-based core genome-MLST and minimum spanning trees were generated. Subjects between 10 and 19 years of age were mostly affected (n = 95; 27.3%). Case fatality rates (CFR) were higher in males (19.4%), as compared to females (15.8%). The highest CFR (31.1%) was observed among those under 5, followed by the 40 to 49 age-group (25.0%). Nine samples corresponded to C. diphtheriae and 1 to C. ulcerans. Two Sequencing Types (ST), ST174 and ST697 (the latter not previously described) were identified among the eight C. diphtheriae isolates from Carabobo state. Cg-MLST revealed only one cluster also from Carabobo. The Whole Genome Sequencing analysis revealed that the outbreak seemed to be caused by different strains with C. diphtheriae and C. ulcerans coexisting. The reemergence and length of this outbreak suggest vaccination coverage problems and an inadequate control strategy.

Hidratación parenteral / Parenteral rehydration

La Rehidratación oral es el método de elección para la deshidratación leve y moderada por diarrea. Sin embargo, en casos de shock hipovolémico, deshidratación grave, hiponatremia o hipernatremia severas, vómitos persistentes, íleo paralítico, en pacientes deshidratados con alteración de conciencia ó convulsiones y cuando ocurre deterioro o ausencia de mejoría clínica tras 8 horas de rehidratación oral, se debe indicar la hidratación endovenosa. Las indicaciones de la hidratación intravenosa varían dependiendo de la gravedad, del tipo (isonatrémica, hiponatrémica o hipernatrémica) y de los déficits de iones y ácido-básico asociados. Se realiza en 2 fases: la primera de emergencia para reponer la volemia si existe shock hipovolémico; y la segunda para reponer el déficit y suministrar las necesidades de mantenimiento de líquidos y electrolitos y las pérdidas concurrentes. Se calculan las necesidades basales de mantenimiento de líquidos y electrolitos por el método de Holliday-Segar y en caso de pacientes con peso mayor a 30 kg, se calculan de acuerdo a la superficie corporal del paciente. Los cálculos del déficit hídrico y de electrolitos se realizan siguiendo los esquemas y fórmulas específicas. Adicionalmente se tratan las complicaciones más frecuentes (acidosis metabólica e hipokalemia) en caso de existir indicaciones definidas. La hidratación del Recién Nacido deshidratado por diarrea es igual que en los lactantes, pero debe considerarse para el tratamiento, su particular balance hidroelectrolítico para evitar complicaciones. Para cada tipo de deshidratación (isonatrémica, hiponatrémica e hipernatrémica) se exponen ejemplos de cálculos para su tratamiento con hidratación endovenosa.

Oral rehydration is the method of choice for mild to moderate dehydration secondary to diarrhea. Intravenous hydration is indicated in hypovolemic shock, severe dehydration, severe hyponatremia or hypernatremia, persistent vomiting, paralytic ileus, in dehydrated patients with impaired consciousness or seizures, and when there is clinical deterioration or no improvement after 8 hours of oral rehydration. Intravenous hydration varies depending on the severity, type of dehydration (isonatrémic, hyponatremic or hypernatremic) and associated ion and acid-base deficits. It is performed in 2 phases: the first is the emergency phase to restore blood volume in cases of hypovolemic shock and the second phase to replenish deficits and to supply maintenance requirements and concurrent loss of fluid and electrolytes. Basal needs are calculated by the method of Holliday and Segar, and for patients weighing more than 30 kg. The patient's body surface is employed as the base for calculations. Fluid and electrolyte deficits are estimated according to specific schemes and formulas. Common complications of dehydration (metabolic acidosis and hypokalemia) should also be addressed with specific indications. Intravenous rehydration in the newborn with dehydration secondary to diarrhea is the same as in infants, but the particular electrolyte balance at this age should be considered in order to avoid complications. Examples of calculations for intravenous hydration for each type of dehydration (isonatrémic, hyponatremic and hypernatremic) are given.