Sakazakii Infections Research Articles

Postsurgical Osteomyelitis Caused by Enterobacter sakazakii in a Healthy Young Man

Enterobacter sakazakii, a Gram-negative rod-shaped bacterium, is a rare cause of invasive infections (meningitis, sepsis, necrotizing enterocolitis) with high death rates (40-80%), primarily in newborns. In contrast to the high number of cases in newborns, infants and children, there are only a few reported cases of E. sakazakii infections in adults, generally in subjects with pre-existing conditions such as neoplasms, and just one osteomyelitis of the foot. We report a confirmed case of postsurgical osteomyelitis of the femur caused by E. sakazakii in a young otherwise healthy man.

<i>Enterobacter sakazakii </i>in infants: Novel phenomenon in India

E. sakazakii has been implicated in necrotizing enterocolitis, bloodstream and central nervous system infections, with mortality rates of 40-80%. Two cases of E. sakazakii infections; one preterm very low birth weight neonate with meningitis and a two month infant with bacteraemia, are described for the first time in India. The first baby succumbed to the infection while the other responded to appropriate therapy. Powdered infant milk formulae have been implicated in causing neonatal infections and the first baby was on formula feed with classic signs of sepsis and meningitis. The second infant was on breast feed and probably developed nosocomial E. sakazakii bacteraemia.

Enterobacter sakazakii bacteriophages can prevent bacterial growth in reconstituted infant formula

Reconstituted infant formula has been implicated in outbreaks of Enterobacter sakazakii infections, causing high mortality and serious sequelae. Current prevention methods appear to be insufficient to ensure that such foods are free of E. sakazakii. In this study, the usefulness of bacteriophages for biocontrol of E. sakazakii was investigated. Of a total of six new E. sakazakii phages isolated from sewage and UV irradiated cultures, two were selected for further study by electron microscopy, DNA restriction analysis and SDS-PAGE of structural proteins. Purified phages were used to control bacterial growth in broth medium and reconstituted infant formula. Both phages effectively prevented development of E. sakazakii in formula at various temperatures (12, 24 and 37 °C), the efficiency of which was dependent upon intrinsic lysis properties and the applied phage concentration. We conclude that application of specific bacteriophages may provide a means for efficient prevention of E. sakazakii infection through reconstituted infant formula.

Acid Resistance of Twelve Strains of Enterobacter sakazakii, and the Impact of Habituating the Cells to an Acidic Environment

ABSTRACT: The association of powdered infant formula with cases of severe Enterobacter sakazakii infections in immunocompromised and premature neonates has led to a need to learn about the basic behavior of this emerging pathogen in food systems and the environment. The current study examines the microorganism's stationary‐phase acid resistance using 12 strains that had been previously used to characterize its thermal resistance. Acid resistance was determined by initially culturing the isolates for 18 h in brain heart infusion broth (BHI) at 36 °C, transferring the cells to tryptic soy broth (TSB) adjusted to pH 3.0 and 3.5, and determining E. sakazakii survival over the course of 5 h incubation at 36 °C. At pH 3.5, 10 of the 12 strains showed less than a 1 log cycle decline over the 5‐h incubation period, with the most acid sensitive strain showing an approximate 3.5 log cycle decline. At pH 3.0, the decline over the 5‐h incubation period ranged from 4.9 to >6.3 log cycles; however, substantial diversity was evident when the 1‐h/pH 3.0 results were compared. The effect of habituating the cells to a moderately acidic environment was determined by growing the strains in TSB with 0% (nonacidogenic) and 1% glucose (acidogenic), transferring the cells to acidified (pH 3.0) BHI, and determining E. sakazakii survival over the course of 5 h of incubation at 36 °C. While there was diversity observed among the strains, in general the stationary‐phase acid resistances of several of the strains were enhanced, at least transitorily, by growth in the acidogenic medium. No apparent correlation between the stationary‐phase relative acid resistances of the strains based on the 1‐h/pH 3.0 acid inactivation values and the previously reported thermal D‐values was observed.

Enterobacter sakazakii is a rare cause of neonatal septicemia or meningitis in vlbw infants

To determine the rates of Enterobacter sakazakii (ES) infections among very low birth weight infants, culture data from the National Institute of Child Health and Human Development Neonatal Research Network were reviewed. Only one case of ES sepsis was identified among 10,660 neonates. These data suggest that outside of the epidemic situation, ES is very rare in very low birth weight infants.

Risk profile of Enterobacter sakazakii, an emergent pathogen associated with infant milk formula

Enterobacter sakazakii infections in neonates cause bacteraemia, necrotizing enterocolitis (NEC) and infant meningitis. Where the source of an outbreak was traced to infant formula milk powder the levels of Enterobacteriacae were below the statutary limit. In order to determine whether a full risk assessment of E. sakazakii in IFM is required, a risk profile is necessary summarizing our knowledge to date. The risk profile presented here includes hazard identification, exposure assessment and hazard characterisation which are parts of a microbiological risk assessment (MRA), as well as risk management. In addition current detection methods are described.