ENTEROBACTER SAKAZAKII INFECTIONS

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ENTEROBACTER SAKAZAKII INFECTIONS
ASSOCIATED WITH
THE USE OF POWDERED INFANT FORMULA
NGUYEN THANH HAI MD.
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• References
• Anna B. Bowen and Christopher R. Braden, Invasive
  Enterobacter sakazakii Disease in Infants,
  Emerging Infectious Diseases, Vol. 12, No. 8,
  August 2006.
• CDC. Enterobacter sakazakii infections
  associated with use of powdered infant
  formulaTennessee, 2001. MMWR Morb Mortal Wkly
  Rep. 200251297300.
• FDA, Isolation and Enumeration of Enterobacter
  sakazakii from Dehydrated Powdered Infant
  Formula, July 2002.
• Jean-Louis Cordier, Travaux de chimie alimentaire
  et dhygiène, Enterobacter sakazakii, Volume 97
  1/2006.

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I. Introduction

• Enterobacter sakazakii is a Gram-negative,
  motile and non-sporing rod belonging to the
  family of the Enterobacteriaceae1,2,3.
• Urmenyi and Franklin1 reported the first two
  known cases of meningitis caused by yellow
  pigmented Enterobacter cloacae in 1961.
• Up to 1980, based on DNA-DNA hybridization
  studies as well as on its biochemical
  characteristics, it has been recognized as an
  individual species and then named after the
  Japanese microbiologist, Professor R. Sakazaki1.

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Since 1961, cases of meningitis, septicemia, and
necrotizing enterocolitis due to E. sakazakii
have been reported worldwide 1.

• Cases were reported in 7 countries in
  North America, Europe, and the Middle East.
  
• 33 (72) infants had meningitis,
• 12 (26) had bacteremia,
• 1 (2) had a urinary tract infection. 1.

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II. Epidemiology4

• E. sakazakii can cause rare but severe
  neonatal diseases such as bloody diarrhoea,
  septicemia, necrotizing enterocolitis (NEC) or,
  most frequently, meningitis.
• According to the published case studies, the
  majority of the babies affected by E. sakazakii
  can be considered as premature babies.
• The onset of illness the large majority of
  infections being reported within the first days
  after birth and up to 1830 days, exceptionally
  to about 6 months.

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II. Epidemiology4

• The reports and studies related to the latter
  cases indicate, however, the occurrence of
  underlying diseases, heavy surgery or even mixed
  infections.
• Cases involving adults have been associated
  with infections (eye, urinary tract,
  diabetic wounds, etc.) but do not seem to be
  linked with foods.
• The fatality rate has been reported to be as high
  as 50100, but a decreasing trend has
  been recorded over the past years. However,
  in several cases where babies have survived the
  infection, chronic neurological disorders have
  been reported.

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III. Behavior4

• E. sakazakii is easily killed at pasteurization
  temperatures (gt60C). It would thus not
  survive normal processing conditions as
  applied by manufacturers.
• It was shown by Nazarowec-White and Farber
  that some strains of E. sakazakii were exhibiting
  resistances to temperatures around 50C, i.e.
  slightly higher than the one of other members of
  the Enterobacteriaceae.
• More rapid growth rate at around 40C, as
  observed by the same authors, could account
  for a competitive advantage after reconstitution
  of the powders and thus favour E. sakazakii over
  other Enterobacteriaceae if present at low
  levels.

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III. Behavior4

• E. sakazakii has been shown to be much more
  resistant to desiccation. This is in line with
  the ability to survive well over prolonged
  periods of time in finished products. These
  findings provide also a logic explanation to the
  ability of E. sakazakii to survive and persist in
  dry processing environments.

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IV. Routes of contamination

• The contaminated infant formulae have been
  identified as the source of E. sakazakii
  mishandling and abuse of reconstituted bottles.
• In several cases extrinsic contamination through
  contaminated utensils such as mixers, brushes or
  bottles used to prepare the formulae, of
  catheters or the incubator have been shown to be
  the likely causes of contamination.
• Recent publications, the occurrence of
  infections in babies which had not been fed
  with powdered infant formulae but with breast.
  These cases as well as the detection of E.
  sakazakii in mother milk stored in milk banks
  show that recontamination at hospital level
  cannot be excluded as source of infection.

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IV. Routes of contamination

• Recent publications have demonstrated that this
  organism is not rare. It can be found in numerous
  foods and raw materials as well as in very
  diverse environments as shown in table.
• No quantitative determinations of the
  ingested E. sakazakii have been performed
  in any of the reported cases.
• However, as discussed in the FAO/WHO report and
  by Havelaar and Zwietering, the risk of infection
  increases dramatically with increasing numbers of
  cells, as is observed in case of growth in
  reconstituted products stored at room
  temperature.

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IV. Routes of contamination

• Quantitative determinations of E. sakazakii
  performed on powdered infant formulae by
  different authors revealed an incidence ranging
  between 3 and 14 of analyzed cans and low levels
  of the organism ranging between 0.36 to 66 cfu
  per 100 g have been determined4.
• E. sakazakii has been isolated from factories
  used to produce milk powder, chocolate, cereal,
  potato flour, spices, and pasta, household vacuum
  cleaner bags1
• Although a human vaginal tract culture yielding
  E. sakazakii has been reported, vertical
  transmission is unlikely because nearly half
  of infants with E. sakazakii disease (in the
  review) were delivered by cesarean section1.

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V. Interim Recommendations for Preparation of
Powdered Infant Formula in the NICU Set

• Formula products should be selected based
  on nutritional needs alternatives to powdered
  forms should be chosen when possible.
• Trained personnel should prepare powdered formula
  under aseptic technique in a designated
  preparation room.
• Manufacturers instructions should be followed
  product should be refrigerated immediately
  and discarded if not used within 24 hours after
  preparation.
• The administration or hang time for continuous
  enteral feeding should not exceed 4 hours.

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VI. Conclusion

• E. sakazakii has to be considered as an
  ubiquitous microorganism.
• It is considered as an opportunistic pathogen.
• It has been at the origin of rare but severe
  cases of infections of premature and neonate
  babies.
• To prevent or mitigate E. sakazakii disease
  follow the recommendations of WHO/FAO (2/2004)
  and Preparation of Powdered Infant Formula in the
  NICU Set

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Thank you