Mannheimia haemolytica growth and leukotoxin production for vaccine manufacturing: a bioprocess review

Mannheimia haemolytica leukotoxin (LKT) is a known cause of bovine respiratory disease (BRD) which results in severe economic losses in the cattle industry (up to USD 1 billion per year in the USA). Vaccines based on LKT offer the most promising measure to contain BRD outbreaks and are already commercially available. However, insufficient LKT yields, predominantly reflecting a lack of knowledge about the LKT expression process, remain a significant engineering problem and further bioprocess optimization is required to increase process efficiency. Most previous investigations have focused on LKT activity and cell growth, but neither of these parameters defines reliable criteria for the improvement of LKT yields. In this article, we review the most important process conditions and operational parameters (temperature, pH, substrate concentration, dissolved oxygen level, medium composition and the presence of metabolites) from a bioprocess engineering perspective, in order to maximize LKT yields.

Microorganismos inusuales en placa subgingival de pacientes con periodontitis crónica / Unusual microorganisms in subgingival plaque of patients with chronic periodontitis

Fundamento: en ambientes subgingivales de pacientes con periodontitis crónica se han encontrado microorganismos inusuales que incluyen bacilos entéricos gramnegativos y levaduras. En estos pacientes la terapia mecánica o antimicrobiana puede ser ineficiente para tratar o controlar la enfermedad periodontal. La característica que comparten los microorganismos inusuales es la de ser patógenos oportunistas, ya que aprovechan las condiciones de inmunodepresión para originar o agravar una enfermedad. Objetivo: presentar la prevalencia de microorganismos inusuales en placa subgingival de pacientes con periodontitis crónica en una población colombiana. Método: se evaluaron 76 pacientes sistémicamente sanos que asistieron a las clínicas odontológicas de la Facultad de Odontología de la Universidad de Antioquia. Las muestras subgingivales se procesaron mediante cultivo. Resultados: se observaron bacilos entéricos gramnegativos en 20 (26.31 %) pacientes y levaduras en 10 (13.2 %). Conclusiones: estos hallazgos tienen implicaciones terapéuticas importantes que deben tenerse en cuenta para el manejo de los pacientes con enfermedades periodontales.

Background: subgingival environment of patients with chronic periodontitis have been found unusual microorganisms including Gram-negative enteric bacilli and yeasts. Mechanical or antimicrobial therapy in these patients may be inefficient to treat or to control periodontal disease. The common feature unusual microorganisms share is to be opportunistic pathogens, taking advantage of immunosuppression conditions to cause or aggravate the disease. Objective: to present the prevalence of unusual microorganisms in subgingival plaque of patients with chronic periodontitis in a Colombian population. Method: 76 systemically healthy patients who were presented in the dental clinic at the Dental School of Antioquia University were evaluated. Subgingival samples were processed by cultivation. Results: enteric Gram-negative bacilli in 20 patients and yeasts in 10 were observed. Conclusions: these findings have important therapeutic implications that must be taken into account for patients management with periodontal diseases.

Endocarditis batteriana por actinobacillus actinomycetemcomitans: reporte de un caso / Bacterial endocartitis by actinobacillus actinomycetemcomitans: a case report

Se presenta un caso de endocarditis bacteriana, niño de seis años ingresado en el Hospital Pediátrico Provincial Docente ‘’Dr. Eduardo Agramonte Piña’’ en el mes de enero de 2006, con una sintomatología que puede inferir la presencia sospechosa de dengue. Se potenciaron exámenes que permitieron descartar esta enfermedad. En el primer hemocultivo realizado se aisló un Actinobacillus actinomycetemcomitans, este microorganismo es un cocobacilo gram negativo, anaerobio facultativo, inmóvil, no formador de esporas que fermenta carbohidratos sin producción de gas, forma parte de la flora normal de la boca humana y es muy sensible a los antimicrobianos, resolvió con el tratamiento antibacteriano impuesto, de ceftriaxona y ciprofloxacina que fue sustituido por gentamicina y ampicillín.

A case of bacterial endocarditis is presented, a boy of six years entered at “Dr. Eduardo Agramonte Piña” Educational Provincial Paediatric Hospital on January 2006, with a symptomatology that can infer the suspicious presence of dengue. Exams were promoted that permitted to reject this illness. In the first hemoculture carried out, an Actinobacillus actinomycetemcomitans was isolated, this microorganism is a gram negative coccobacillus, facultative anaerobe, motionless, not spores former that ferments carbohydrates without gas production, it is a part of the normal flora of the human mouth and is very sensitive to the antimicrobial, the patient solved with the antibacterial treatment, of ceftriaxone and ciprofloxacin that was substituted by gentamyicin and ampicillin.