Cronobacter sakazakii
Cronobacter sakazakii, which before 2007 was named Enterobacter sakazakii, is an opportunistic Gram-negative, rod-shaped, pathogenic bacterium that can live in very dry places, otherwise known as xerotolerance. C. sakazakii utilizes a number of genes to survive desiccation and this xerotolerance may be strain specific. The majority of C. sakazakii cases are adults but low-birth-weight preterm neonatal and older infants are at the highest risk. The pathogen is a rare cause of invasive infection in infants, with historically high case fatality rates (40–80%).
| Cronobacter sakazakii | |
|---|---|
| Cronobacter sakazakii | |
| Scientific classification | |
| Domain: | Bacteria |
| Phylum: | Pseudomonadota |
| Class: | Gammaproteobacteria |
| Order: | Enterobacterales |
| Family: | Enterobacteriaceae |
| Genus: | Cronobacter |
| Species: | C. sakazakii |
| Binomial name | |
| Cronobacter sakazakii (Farmer et al. 1980) | |
In infants it can cause bacteraemia, meningitis and necrotizing enterocolitis. Most neonatal C. sakazakii infections cases have been associated with the use of powdered infant formula with some strains able to survive in a desiccated state for more than two years. However, not all cases have been linked to contaminated infant formula. In November 2011, several shipments of Kotex tampons were recalled due to a Cronobacter (E. sakazakii) contamination. In one study, the pathogen was found in 12% of field vegetables and 13% of hydroponic vegetables.
All Cronobacter species, except C. condimenti, have been linked retrospectively to clinical cases of infection in either adults or infants. However multilocus sequence typing has shown that the majority of neonatal meningitis cases in the past 30 years, across 6 countries, have been associated with only one genetic lineage of the species Cronobacter sakazakii called 'Sequence Type 4' or 'ST4', and therefore this clone appears to be of greatest concern with infant infections.
The bacterium is ubiquitous, being isolated from a range of environments and foods; the majority of Cronobacter cases occur in the adult population. However it is the association with intrinsically or extrinsically contaminated powdered formula which has attracted the main attention. According to multilocus sequence analysis (MLSA) the genus originated ~40 MYA, and the most clinically significant species, C. sakazakii, was distinguishable ~15-23 MYA.