Cronobacter multi-species complex (formerly Enterobacter sakazakii) is a group of gram-negative bacteria that exists in the environment and which can survive in very dry conditions. The natural habitat for Cronobacter is not known. It has been found in a variety of dry foods, including powdered infant formula, skimmed milk powder, herbal teas, and starches. It has also been found in wastewater. Cronobacter illnesses are rare, but they are frequently lethal for infants and can be serious among people with immunocompromising conditions and the elderly.
Infants suspected of having Cronobacter sepsis or meningitis should undergo a full clinical evaluation for sepsis, including blood culture, urine culture, and cerebrospinal fluid culture, and should be given empiric therapy for sepsis immediately. Antimicrobial sensitivity patterns of Cronobacter isolates should be determined because multidrug-resistant strains have been reported. Brain imaging studies of infants with meningitis can help detect brain abscesses and other complications. People with urinary tract infections or serious wound infections should also be treated with antibiotics. If a patient is colonized, rather than infected, with Cronobacter, treatment is not needed.
Major research on disease
Current research on E. sakazakii focuses on the elimination of this coliform from PIF. Investigations into thermal resistance, osmotic tolerance, exopolysaccharide production, and pathogenicity, among others, have been performed, and attempts have been made to identify environmental reservoirs. Only 1 study has suggested the possible existence of an enterotoxin produced by E. sakazakii on the basis of an animal model. Other virulence factors remain to be identified. Furthermore, why infection can occur in all age groups but is more frequent among full-term infants and neonates remains to be understood.
An analysis of current case numbers, epidemiological measures and risk factors is warranted. Data of microbiologically confirmed cases, published between 2000 and 2008, have been analysed statistically. More than 100 neonatal Cronobacter infections have been reported in this period. The overall lethality of the 67 invasive infections was 26.9%. The lethality of Cronobacter meningitis, bacteraemia and necrotising enterocolitis (NEC) was calculated to be 41.9% (P < 0.0001), <10% and 19.0% (P < 0.05), respectively. Logistic regression models (P < 0.0001) revealed a higher gestational age at birth and parentage not from Europe as significant factors for a higher reporting probability of neonatal Cronobacter meningitis.