Enfamil Baby Formula 2011, Infant Death and Cronobacter (Enterobacter) sakazakii
©Donald Reinhardt, December 24, 2011. Updated December 25, 26, 28, 31, 2011.
Mead Johnson, the CDC, FDA and the Missouri Health and Senior Services reported on Dec. 30, 2011 that the one investigated lot of Mead Johnson's Enfamil was not found to be a bacterially-contaminated formula of the sealed containers.
Updates – Bacterial Infections in 2011 Related to Infant Formulas
The Washington Post reported three bacterial infections in December 28, 2011 of Cronobacter sakazakii related to at least two different brands of powdered infant formula. One infant in Oklahoma (Tulsa County) and another in Indiana were infected and both recovered. A 10-day infant, Avery Cornett, in Missouri became infected and died and an investigation followed on this case also. The FDA, CDC and Missouri laboratories have all investigated the possible and probable sources of this Missouri infection and the report of December 30, 2011 concludes there is no contamination of the commercial formula. Further, there is no evidence of contamination of the nursery water.
The Nature and Ecology of Gram Negative Bacteria Enteric Bacteria
Gram-negative bacteria can cause serious human infections and disease. Sometimes these bacteria cause death. The CDC report by Bowen and Braden in 2006 Emerging Infectious Diseases indicated a fatality rate of 40 to 80% in the infected infants by Cronobacter (Enterobacter) sakazakii. Contaminated infant, powdered formulas were one of the most common sources or reservoirs for these infections. Since formulas are prepared with water, contaminated water used to prepare infant formulas are also sources of microorganisms.
Cronobacter sakazakii was formerly called Enterobacter sakazakii. This is a small bacterium which is a common environmental microbe and contaminant of air, water and various raw materials. Cronobacter sakazakii is occasionally found in commercial fluids, powders and foods prepared in various processing and industrial facilities.
The bacterium is a member of a large family of bacteria commonly called the enteric bacteria. In humans, there are about 120 different species of bacteria and other types of such as microbes such as yeasts in the digestive tract. Some species of these bacteria grow and multiply into dense populations that number in the billions per gram of intestinal contents.
Many intestinal bacteria are helpful to the digestive process and these microbes often provide host protection against pathogens – the more dangerous bacteria such as Salmonella. However, under certain circumstances, some bacteria may gain entrance to the blood (bacteremia, septicemia) and organ systems of the body (e.g. hepatitis, hydrocephalis, meningitis, encephalitis). Signs of disease may include one or more of the following: prolonged bouts of crying, seizures, lethargy, unresponsiveness and fever. When invading tissue and organ sites, these pathogenic microbes often cause serious injury to the cells, tissues and organs and may even cause death of the infected patient. Infants are particularly at higher risk because of their young and immature immune systems.
Epidemiology-Bacterial Studies Reveal No Cronobacter in Enfamil Lot and Infant Death Not Sourced to Unopened Product
The presence of a bacterium Cronobacter sakazakii in one infant patient has been shown, but the tested, factory-sealed Enfamil containers when opened and tested have not revealed the presence of the deadly bacterium. Mead Johnson originally reported that followup control samples and studies of the quality-control lot of Enfamil infant formula did not reveal or indicate the presence of this bacterium. The FDA and CDC results confirm this to be true as tested by their independent, outside lab evaluations. Mead Johnson's preliminary report was as follows:
The batch of the product used by the child’s family did not show the presence of the bacteria when it was produced and packaged, and that has recently been reconfirmed from our batch records. This product is not being recalled – nor is any other Mead Johnson product – but some retailers are removing it from their shelves as a precautionary measure. The product is Enfamil PREMIUM Newborn 12.5 ounce powder with number ZP1K7G on the bottom of the can.
(From the Mead Johnson Blog cited above)
The second round of rigorous lab testing completed by Mead Johnson's quality control lab indicated in that news release report of December 25, 2011 no evidence of Cronobacter sakazakii in the Enfamil powder. And since the FDA and CDC tests as reported on December 30, 2011 also are negative this means that all the combined lab data strongly indicate that the infection and death of the baby cannot be tied to manufacturer-contaminated Enfamil formula and that other explanations and discoveries will be required.
The December 30, 2011 report of the CDC and the FDA information is as follows and is quoted in italics:
The following results have been confirmed from completed laboratory tests, although additional lab results are pending release:
- CDC's laboratory conducted DNA fingerprinting of the bacteria from two recent cases of Cronobacter infection in infants (Missouri and Illinois). The results show that the Cronobacter bacteria differ genetically, suggesting that they are not related. (Bacteria from cases in Oklahoma and Florida are not available for analysis.)
- CDC laboratory tests of samples provided by the Missouri Department of Health and Senior Services found Cronobacter bacteria in an opened container of infant formula, an opened bottle of nursery water and prepared infant formula. It is unclear how the contamination occurred.
- The FDA tested factory sealed containers of powdered infant formula and nursery water with the same lot numbers as the opened containers collected from Missouri and no Cronobacter bacteria were found.
The FDA has inspected the facilities that manufactured the infant formula and the nursery water that tested positive for Cronobacter bacteria. Those manufacturers have programs that test their products before they are distributed. The lots in question were tested and found negative for Cronobacter. There is currently no evidence to conclude that the infant formula or nursery water was contaminated during manufacturing or shipping.
The FDA, CDC and state agencies continue to investigate the cause of the infections using epidemiological and laboratory methods. Currently CDC and FDA laboratories are testing infant formula, water and other environmental samples related to the ill infants from Illinois and Oklahoma; the results are pending. Additional steps include: completion of inspections of manufacturers, additional laboratory testing of samples, and additional DNA fingerprinting investigation.
As a research microbiologist and consultant who has written this article I cautioned that everyone needed to remember that contaminated water used to prepare formula, or improper or inadequate preparation or storage of the formula at the household, were also unresolved issues under investigation. CDC, FDA and Missouri all have reported contamination with Cronobacter in that the opened container, formula and water from the household of the infant who was infected. Adults who prepare or mishandle a good product in their home environment unintentionally may contaminate the product with harmful bacteria. The updated FDA report of 2002 clearly points out the importance of preparing small batches of powdered formula and limiting the time of room-temperature exposure and use of such formulations to four hours or less.
In summary, as of the time of this report on December 31, 2011, there is no proof of Enfamil contamination in samples of the factory lot, nor is there evidence of bacterial contamination within marketed, packaged formula shipped and used outside the manufacturing facility. At this stage of the investigation some unknown manner of contamination occurred in the household of the now-deceased baby Avery Cornett.
CDC and Missouri State Officials Continue to Investigate
This study has expanded to other possible infants who experience illness and any suspect baby formulas will be sent to a qualified FDA laboratory for investigation. Enfamil PREMIUM Newborn 12.5 ounce powder with the number ZP1K7G on the bottom of the can was the suspect lot and is probably no longer to be considered hazardous for consumer use.
This article will continue to update as further information is received. If you bookmark this article, you can return to the regularly-updated article. We will be in direct contact with federal, state and manufacturing officials.
Enterobacter sp. from vegetation/ plant material. Electron Micrograph Photo Credit: Dr. Barbara Panessa Warren
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