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.
The cases occurred among patients over a 6-year period. Forty-eight cases were due to Enterobacter cloacae and five were due to Ent. aerogenes. Enterobacter bacteraemia was more often of nosocomial origin than E. coli bacteraemia and more often polymicrobial. Patients suffering from enterobacter bacteraemia were younger than E. coli patients, and males tended to predominate. Enterobacter bacteraemia was more often associated with a focus in central venous catheters and burns, whereas patients with E. coli bacteraemia more often showed a focus of infection in the urinary tract. Patients with enterobacter bacteraemia and a microbiologically documented focus in the respiratory tract or the urinary tract more often had an endotracheal tube or indwelling urinary catheter compared to patients with E. coli bacteraemia with a similar focus of infection. In patients with no microbiologically documented focus enterobacter bacteraemia was more often associated with the presence of central and peripheral venous catheters. During the preceding 12 weeks patients with enterobacter bacteraemia, more often than E. coli patients, had been treated with beta-lactam antibiotics, especially penicillins.