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Published on: February 13, 2015
Isolation and molecular identification of Cronobacter spp. from powdered infant formula (PIF) in Bangladesh
Ashfaqul Hoque1, Tahmeed Ahmed, Mohammad Shahidullah
1International Center for Diarrhoeal Disease Research, Bangladesh (ICDDR,B), Dhaka, Bangladesh.
Insights
Cronobacter contamination was not detected in clinical samples from neonates and children in Bangladesh. However, one powdered infant formula (PIF) sample tested positive for Cronobacter, marking the first such report in Bangladesh.
Area of Science:
- Food safety
- Microbiology
- Public health
Background:
- Cronobacter spp., previously Enterobacter sakazakii, is a pathogen linked to severe infant illnesses like meningitis and necrotizing enterocolitis (NEC).
- The International Commission for Microbiological Specifications for Foods (ICMSF) classifies Cronobacter as a severe hazard, particularly for vulnerable populations.
- Infant health risks necessitate vigilant monitoring of potential contamination sources like powdered infant formula (PIF).
Purpose of the Study:
- To investigate the presence of Cronobacter spp. in clinical samples from neonates and children in Bangladesh.
- To determine the contamination status of PIF samples available in Bangladeshi retail markets.
- To identify and characterize any detected Cronobacter isolates using microbiological and molecular techniques.
Main Methods:
- Clinical samples (blood, stool, CSF) from 93 neonates and children (0-24 months) were analyzed for Cronobacter.
- 32 PIF samples from retail markets in Bangladesh were screened for Cronobacter contamination.
- Identification of isolates involved chromogenic DFI agar, conventional PCR targeting alpha glucosidase and 16S rRNA genes, and partial 16S rRNA gene sequencing for phylogenetic analysis.
Main Results:
- Cronobacter spp. were not detected in any of the analyzed clinical samples.
- One out of 32 PIF samples (3.1%) collected from retail markets in Bangladesh was found to be contaminated with Cronobacter sp.
- The identified isolate (DA01) exhibited typical culture characteristics and genetic markers, with phylogenetic analysis showing clustering with other Cronobacter isolates.
Conclusions:
- This study did not find evidence of Cronobacter spp. in clinical samples from the studied neonate and child population in Bangladesh.
- The detection of Cronobacter in a PIF sample represents the first reported instance in Bangladesh, highlighting a potential public health concern.
- The findings underscore the importance of continued surveillance and control measures to ensure the safety of PIF for infants.
Abstract:
Cronobacter spp. formerly known as Enterobacter sakazakii is an occasional contaminant of powdered infant formula (PIF). This pathogen has been associated with out-breaks of a rare form of infant meningitis, necrotizing enterocolitis (NEC), bacteremia and neonate deaths. The organism is ranked by the International Commission for Microbiological Specifications for Foods (ICMSF) as a 'Severe hazard for restricted populations, life threatening or substantial chronic sequelae or long duration'. Present study aimed to isolate Cronobacter spp. from PIF and clinical samples, such as blood, stool and CSF collected from 93 neonates and child patients, age ranged from 0 to 24months. We did not detect Cronobacter spp. in any of these samples. Later 32 PIF samples collected from retail markets in Bangladesh were tested for the presence of Cronobacter spp. Of these only one was found to be contaminated with Cronobacter sp. This is the first case of Cronobacter contaminated PIF found in Bangladesh to be reported. The organism was successfully identified based on its typical culture characteristics, producing blue-green colonies on chromogenic DFI agar and also by a standardized conventional PCR assay targeting the alpha glucosidase and 16S rRNA gene sequence of Cronobacter sp. The 16S rRNA gene was partially sequenced to provide for the phylogenetic analysis of this isolate (DA01) and found to cluster with some other Cronobacter isolates in the phylogram.
