Lactobacillus bulgaricus prevents intestinal epithelial cell injury caused by Enterobacter sakazakii-induced nitric oxide both in vitro and in the newborn rat model of necrotizing enterocolitis
Authors: Catherine J Hunter
Rahul Mittal
Dennis Mock
Mikael Petrosyan
Henri R Ford
Jeffrey S Upperman
Nemani V Prasadarao
Yigit Guner
Monica Williams
Journal: Infection and Immunity (2009)
Discipline: IMMUNOLOGY
Keywords: Enterobacter sakazakii; necrotizing enterocolitis; apoptosis; nitric oxide; inducible NO synthase
Affiliations: Department of Surgery, The Saban Research Institute, Children's Hospital Los Angeles, and Keck School of Medicine, University of Southern California,4 Los Angeles, California 90027, USA., Department of Surgery, Department of Infectious Diseases, Department of Pathology, The Saban Research Institute, Children's Hospital Los Angeles, Keck School of Medicine, University of Southern California, Los Angeles, California 90027

Abstract:  Enterobacter sakazakii is an emerging pathogen that has been associated with outbreaks of necrotizing enterocolitis (NEC) as well as infant sepsis and meningitis. Our previous studies demonstrated that E. sakazakii induces NEC in a newborn rat model by inducing enterocyte apoptosis. However, the mechanisms responsible for enterocyte apoptosis are not known. Here we demonstrate that E. sakazakii induces significant production of nitric oxide (NO) in rat intestinal epithelial cells (IEC-6) upon infection. The elevated production of NO, which is due to increased expression of inducible NO synthase, is responsible for apoptosis of IEC-6 cells. Notably, pretreatment of IEC-6 cells with Lactobacillus bulgaricus (ATCC 12278) attenuated the upregulation of NO production and thereby protected the cells from E. sakazakii-induced apoptosis. Furthermore, pretreatment with L. bulgaricus promoted the integrity of enterocytes both in vitro and in the infant rat model of NEC, even after challenge with E. sakazakii. Infection of IEC-6 cells with E. sakazakii upregulated several genes related to apoptosis, cytokine production, and various signaling pathways, as demonstrated by rat gene array analysis, and this upregulation was subdued by pretreatment with L. bulgaricus. In agreement with these data, L. bulgaricus pretreatment protected newborn rats infected with E. sakazakii from developing NEC, resulting in improved survival. 

Retracted: No

PubPeer comments:
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 2018 retraction. http: iai.asm.org content 86 6 e00212-18 RETRACTION Volume 77, no. 3, p. 1031u20131043, 2009, https: doi.org 10.1128 IAI.01192-08. The publisher hereby retracts this article. Questions have been raised by concerned readers about the integrity of the data. The American Society for Microbiology has reviewed the figures and confirmed evidence of apparent duplication of cell images and Western blot bands in Fig. 1C, 2D, 5A, and 5B. Since the integrity of the data as presented was compromised, this publication is retracted in its entirety. We apologize to the readers of Infection and Immunity and regret any inconvenience that this causes. , 
 Here are the concerns as communicated with the journal in March of 2015.  , 
 Two recent Retraction Watch articles and an ORI report about this case: * Infectious disease researcher u201crecklesslyu201d faked data in grants worth millions, says federal watchdog - https: retractionwatch.com 2020 07 21 infectious-disease-researcher-recklessly-faked-data-in-grants-worth-millions-says-federal-watchdog * USC-Childrenu2019s Hospital Los Angeles researcher out following misconduct probe - https: retractionwatch.com 2020 07 29 usc-childrens-hospital-los-angeles-researcher-out-following-misconduct-probe * Case Summary: Nemani, Prasadarao - https: ori.hhs.gov content case-summary-nemani-prasadarao ,