Cronobacter sakazakii, which before 2007 was named Enterobacter sakazakii,[2][3] is an opportunistic Gram-negative, rod-shaped, pathogenic bacterium that can live in very dry places, a phenomenon known as xerotolerance. C. sakazakii utilizes a number of genes to survive desiccation[4] and this xerotolerance may be strain specific.[5] 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%).[6][7][8][9]

Cronobacter sakazakii
Cronobacter sakazakii growing in a petri dish
Colonies on trypticase soy broth agar
Scientific classification Edit this classification
Domain: Bacteria
Phylum: Pseudomonadota
Class: Gammaproteobacteria
Order: Enterobacterales
Family: Enterobacteriaceae
Genus: Cronobacter
Species:
C. sakazakii
Binomial name
Cronobacter sakazakii
(Farmer et al. 1980)[1]

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[7][9] with some strains able to survive in a desiccated state for more than two years.[10] 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.[11][12]

All Cronobacter species, except C. condimenti, have been linked retrospectively to clinical cases of infection in either adults or infants. However multilocus sequence typing[13] has shown that the majority of neonatal meningitis cases in the past 30 years, across six countries, have been associated with only one genetic lineage of the species Cronobacter sakazakii called 'Sequence Type 4' or 'ST4',[14] 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.[15]

Taxonomy

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E. sakazakii was defined as a species in 1980 by JJ Farmer III et al.[1] DNA–DNA hybridization showed that E. sakazakii was 53–54% related to species in two different genera, Enterobacter and Citrobacter. However, diverse biogroups within E. sakazakii were described and Farmer et al suggested these may represent different species and required further research for clarification.[1]

The taxonomic relationship between E. sakazakii strains has been studied using full-length 16S rRNA gene sequencing, DNA–DNA hybridization, multilocus sequence typing (MLST), f-AFLP, automated ribotyping. This resulted in the classification of E. sakazakii as a new genus, Cronobacter within the Enterobacteriaceae, initially comprising four named species in 2007. The taxonomy was expanded to five named species in 2008, and more recently (2011) to seven named species.[2][3][16]

The initial four named species in 2007 were Cronobacter sakazakii (comprising two subspecies), C. turicensis, C. muytjensii and C. dublinensis (comprising three subspecies) plus an unnamed species referred to as Cronobacter genomospecies I.[16] The taxonomy was revised in 2008 to include a fifth named species C. malonaticus, which in 2007 had been regarded as a subspecies of C. sakazakii.[2] In 2012, Cronobacter genomospecies I was formally renamed Cronobacter universalis, and a seventh species was described called Cronobacter condimenti.[3]

Etymology

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The first documented isolation of what would become known as Cronobacter sakazakii was from a can of dried milk in 1950, although these organisms have likely existed for millions of years. In 1980, John J. Farmer III, proposed the name Enterobacter sakazakii for what had been known as "yellow-pigmented E. cloacae", in honor of Japanese bacteriologist Riichi Sakazaki. Over the next decades, E. sakazakii was implicated in scores of cases of meningitis and sepsis among infants, frequently in association with powdered infant formula. In 2007, the genus Cronobacter was created to accommodate the biogroups of E. sakazakii, with C. sakazakii as the type species. The genus was named for Cronos, the Titan of Greek myth, who devoured his children as they were born.[17]

References

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  1. ^ a b c Farmer JJ III, Asbury MA, Hickman FW, Brenner DJ (1980). "Enterobacter sakazakii: a new species of "Enterobacteriaceae" isolated from clinical specimens". Int J Syst Bacteriol. 30 (3). the Enterobacteriaceae Study Group (USA): 569–84. doi:10.1099/00207713-30-3-569.
  2. ^ a b c Iversen C, Mullane N, McCardell B, Tall BD, Lehner A, Fanning S, Stephan R, Joosten H (2008). "Cronobacter gen. nov., a new genus to accommodate the biogroups of Enterobacter sakazakii, and proposal of Cronobacter sakazakii gen. nov. comb. nov., C. malonaticus sp. nov., C. turicensis sp. nov., C. muytjensii sp. nov., C. dublinensis sp. nov., Cronobacter genomospecies 1, and of three subspecies, C. dublinensis sp. nov. subsp. dublinensis subsp. nov., C. dublinensis sp. nov. subsp. lausannensis subsp. nov., and C. dublinensis sp. nov. subsp. lactaridi subsp. nov". International Journal of Systematic and Evolutionary Microbiology. 58 (6): 1442–7. doi:10.1099/ijs.0.65577-0. PMID 18523192. S2CID 6609941.
  3. ^ a b c Joseph S, Cetinkaya E, Drahovska H, Levican A, Figueras MJ, Forsythe SJ (2012). "Cronobacter condimenti sp. nov., isolated from spiced meat and Cronobacter universalis sp. nov., a novel species designation for Cronobacter sp. genomospecies 1, recovered from a leg infection, water, and food ingredients". Int J Syst Evol Microbiol. 62 (Pt 6): 1277–1283. doi:10.1099/ijs.0.032292-0. PMID 22661070.
  4. ^ Srikumar S, Cao Y, Yan Q, Van Hoorde K, Nguyen S, Cooney S, Gopinath GR, Tall BD, Sivasankaran SK, Lehner A, Stephan R, Fanning S (January 2019). "RNA Sequencing-Based Transcriptional Overview of Xerotolerance in Cronobacter sakazakii SP291". Applied and Environmental Microbiology. 85 (3). Bibcode:2019ApEnM..85E1993S. doi:10.1128/AEM.01993-18. PMC 6344630. PMID 30446557.
  5. ^ Cao Y, Dever K, Van Hoorde K, Sivasankaran SK, Nguyen SV, Macori G, Naithani A, Gopinath GR, Tall B, Lehner A, Stephan R, Srikumar S, Fanning S (November 2021). "Alterations in the Transcriptional Landscape Allow Differential Desiccation Tolerance in Clinical Cronobacter sakazakii". Applied and Environmental Microbiology. 87 (24): e0083021. Bibcode:2021ApEnM..87E.830C. doi:10.1128/AEM.00830-21. PMC 8612285. PMID 34644165.
  6. ^ Hunter, Catherine J.; Petrosyan, Mikael; Ford, Henri R.; Prasadarao, Nemani V. (2017-04-28). "Enterobacter sakazakii: An Emerging Pathogen in Infants and Neonates". Surgical Infections. 9 (5): 533–539. doi:10.1089/sur.2008.006. ISSN 1096-2964. PMC 2579942. PMID 18687047.
  7. ^ a b Centers for Disease Control Prevention (CDC) (April 2002). "Enterobacter sakazakii infections associated with the use of powdered infant formula--Tennessee, 2001". MMWR. Morbidity and Mortality Weekly Report. 51 (14): 297–300. PMID 12002167. Free full text
  8. ^ Lai KK (March 2001). "Enterobacter sakazakii infections among neonates, infants, children, and adults. Case reports and a review of the literature". Medicine. 80 (2): 113–22. doi:10.1097/00005792-200103000-00004. PMID 11307587. S2CID 7515008.
  9. ^ a b Bowen AB, Braden CR (August 2006). "Invasive Enterobacter sakazakii disease in infants". Emerging Infectious Diseases. 12 (8): 1185–9. doi:10.3201/eid1208.051509. PMC 3291213. PMID 16965695.
  10. ^ Caubilla-Barron J, Forsythe S (2007). "Dry stress and survival time of Enterobacter sakazakii and other Enterobacteriaceae in dehydrated infant formula". Journal of Food Protection. 13: 467–472.
  11. ^ Ueda, Shigeko (2017-01-01). "Occurrence of Cronobacter spp. in Dried Foods, Fresh Vegetables and Soil". Biocontrol Science. 22 (1): 55–59. doi:10.4265/bio.22.55. ISSN 1884-0205. PMID 28367871.
  12. ^ "FDA Recall of Kotex Tampons". Seeger Weiss LLP. 2011-11-16. Archived from the original on 2014-09-05. Retrieved 2012-02-29.
  13. ^ Baldwin A, Loughlin M, Caubilla-Baron J, Kucerova E, Manning G, Dowson C, Forsythe S (2009). "Multilocus sequence typing of Cronobacter sakazakii and Cronobacter malonaticus reveals stable clonal structures with clinical significance which do not correlate with biotypes". BMC Microbiology. 9: 223. doi:10.1186/1471-2180-9-223. PMC 2770063. PMID 19852808.
  14. ^ Joseph S, Forsythe SJ (2011). "Association of Cronobacter sakazakii ST4 with neonatal infections". Emerging Infectious Diseases. 17 (9): 1713–5. doi:10.3201/eid1709.110260. PMC 3322087. PMID 21888801.
  15. ^ Joseph S, Sonbol H, Hariri S, Desai P, McClelland M, Forsythe SJ (September 2012). "Diversity of the Cronobacter genus as revealed by multilocus sequence typing". Journal of Clinical Microbiology. 50 (9): 3031–9. doi:10.1128/JCM.00905-12. PMC 3421776. PMID 22785185.
  16. ^ a b Iversen C, Lehner A, Mullane N, Bidlas E, Cleenwerck I, Marugg J, Fanning S, Stephan R, Joosten H (2007). "The taxonomy of Enterobacter sakazakii: proposal of a new genus Cronobacter gen. nov. and descriptions of Cronobacter sakazakii comb. nov. Cronobacter sakazakii subsp. sakazakii, comb. nov., Cronobacter sakazakii subsp. malonaticus subsp. nov., Cronobacter turicensis sp. nov., Cronobacter muytjensii sp. nov., Cronobacter dublinensis sp. nov. and Cronobacter genomospecies 1". BMC Evolutionary Biology. 7 (1): 64. Bibcode:2007BMCEE...7...64I. doi:10.1186/1471-2148-7-64. PMC 1868726. PMID 17439656.
  17. ^ Henry, Ronnie (November 2018). "Etymologia: Cronobacter sakazakii". Emerg Infect Dis. 24 (11): 2124. doi:10.3201/eid2411.et2411. PMC 6199989.
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