Cronobacter Support
04-03-2009, 11:07 AM
CLINICAL PRESENTATION
Enterobacteriaceae is the most important family of gram-negative bacteria. Bacteria of this family are responsible of infections affecting bile ducts, prostate, the urinary tract, and of the most common nosocomial infections. The main source of diffusion and transmission to sensitive sites is the intestine.
E. sakazakii, one of the bacteria of the enterobacteriaceae family, is considered an invasive opportunistic pathogen responsible of sepsis, meningitis, and necrotizing enterocolitis (NEC), especially among newborns (premature, underweight, affected by immunodeficiency) and of nosocomial infections, especially in paediatric intensive care units where it causes almost 50% of infections. The most severe infection caused by E. sakazakii is meningitis. The pathway the pathogen follows to reach the cerebral spinal liquid and cause meningitis is unknown. It is widely assumed that the route of infection is the carotid plexus; paracellular and transcellular mechanisms are involved. Bacterial glycopeptides, endotoxins, proteases, and elastases seem to induce permeability of haematic and cerebral barriers opening the way to the pathogen. The most common pathological symptoms in advanced stages of meningitis, are: ventriculitis, cerebral abscess, formation of cysts, hydrocephalus, quadriplegia, retarded neural development and infarction. Patients who recover from the disease suffer from physical and mental retardation.
E. sakazakii, in the same way as Pneumococcus, Haemophilus and Meningococcus, which cause meningitis among children below 5, has a particular tropism for the central nervous system. On the basis of its tendency to cause cerebral lesions, it has been compared to Citrobacter diversus.
Neonatal necrotizing enterocolitis is characterized by necrosis and intestinal pneumatosis. The disease affects 13% of underweight infants.
Essential prerequisites for the pathogenesis of this disease seem to be: neonatal intestinal ischaemia, microbial colonization of the intestine and excess of proteins in the intestinal lumen associated with administration of infant formula. The presence of necrotizing enterocolitis among infants fed with artificial milk is ten times higher than among breastfed infants; this is probably due to the presence of class A protective immunoglobulins in maternal milk.
Necrotizing enterocolitis as well as meningitis cause high mortality. In particular, with respect to necrotizing enterocolitis, the percentage varies between 10% and 55%, while in respect to meningitis it varies between 40% and 80%.
Neonatal infections due to E. sakazakii could also be contracted directly from the mother at birth, but no cases of intestinal and genital infections have been reported among mothers of infected newborns. Cases of neonatal infections after a caesarean section have been reported [29]. Nevertheless, colonization of infants, especially if premature, with human and environmental bacteria is almost inevitable.
The signs and symptoms of the initial phase of E. sakazakii infection are: anorexia, irritability, jaundice, paleness, cyanosis, collapse, spasms and temperature instability.
Posted from iss.it Title of entire text: Enterobacter sakazakii: epidemiology, clinical presentation, prevention and control
Alfonsina Fiore, Maria Casale and Paolo Aureli
Dipartimento di Sanità Pubblica Veterinaria e Sicurezza Alimentare,
Istituto Superiore di Sanità, Rome, Italy
Enterobacteriaceae is the most important family of gram-negative bacteria. Bacteria of this family are responsible of infections affecting bile ducts, prostate, the urinary tract, and of the most common nosocomial infections. The main source of diffusion and transmission to sensitive sites is the intestine.
E. sakazakii, one of the bacteria of the enterobacteriaceae family, is considered an invasive opportunistic pathogen responsible of sepsis, meningitis, and necrotizing enterocolitis (NEC), especially among newborns (premature, underweight, affected by immunodeficiency) and of nosocomial infections, especially in paediatric intensive care units where it causes almost 50% of infections. The most severe infection caused by E. sakazakii is meningitis. The pathway the pathogen follows to reach the cerebral spinal liquid and cause meningitis is unknown. It is widely assumed that the route of infection is the carotid plexus; paracellular and transcellular mechanisms are involved. Bacterial glycopeptides, endotoxins, proteases, and elastases seem to induce permeability of haematic and cerebral barriers opening the way to the pathogen. The most common pathological symptoms in advanced stages of meningitis, are: ventriculitis, cerebral abscess, formation of cysts, hydrocephalus, quadriplegia, retarded neural development and infarction. Patients who recover from the disease suffer from physical and mental retardation.
E. sakazakii, in the same way as Pneumococcus, Haemophilus and Meningococcus, which cause meningitis among children below 5, has a particular tropism for the central nervous system. On the basis of its tendency to cause cerebral lesions, it has been compared to Citrobacter diversus.
Neonatal necrotizing enterocolitis is characterized by necrosis and intestinal pneumatosis. The disease affects 13% of underweight infants.
Essential prerequisites for the pathogenesis of this disease seem to be: neonatal intestinal ischaemia, microbial colonization of the intestine and excess of proteins in the intestinal lumen associated with administration of infant formula. The presence of necrotizing enterocolitis among infants fed with artificial milk is ten times higher than among breastfed infants; this is probably due to the presence of class A protective immunoglobulins in maternal milk.
Necrotizing enterocolitis as well as meningitis cause high mortality. In particular, with respect to necrotizing enterocolitis, the percentage varies between 10% and 55%, while in respect to meningitis it varies between 40% and 80%.
Neonatal infections due to E. sakazakii could also be contracted directly from the mother at birth, but no cases of intestinal and genital infections have been reported among mothers of infected newborns. Cases of neonatal infections after a caesarean section have been reported [29]. Nevertheless, colonization of infants, especially if premature, with human and environmental bacteria is almost inevitable.
The signs and symptoms of the initial phase of E. sakazakii infection are: anorexia, irritability, jaundice, paleness, cyanosis, collapse, spasms and temperature instability.
Posted from iss.it Title of entire text: Enterobacter sakazakii: epidemiology, clinical presentation, prevention and control
Alfonsina Fiore, Maria Casale and Paolo Aureli
Dipartimento di Sanità Pubblica Veterinaria e Sicurezza Alimentare,
Istituto Superiore di Sanità, Rome, Italy