Molecular identification of coliform bacteria from colicky breastfed infants

Objective: To determine the presence of intestinal coliform bacteria in colicky vs healthy infants. Study design: We isolated coliform strains from faeces and performed quantitative bacterial cultures in 41 colicky and 39 healthy breastfed infants, identified using PCR with species-specific primers, strain-specific Automated Ribotyping and the API-50E kit for Enterobacteriaceae to identify the most frequent strains. Results: Coliform strains were more abundant in colicky infants (median 6.04 log(10) CFU/g faeces, range 2.00-8.76) vs controls (median 4.47 log(10) CFU/g faeces, range 1.00-8.08) (p = 0.026). Escherichia coli, Klebsiella pneumoniae, K. oxytoca, Enterobacter cloacae, E. aerogenes and Enterococcus faecalis were the predominant species in colicky and healthy infants. The counts of each bacterial species differed between the two groups, and the difference was significant (p = 0.002) for E. coli: median 6.30 log(10) CFU/g faeces (range 3.00-8.74) in colicky infants, and median 4.70 log(10) CFU/g faeces (range 2.00-5.85) in controls. Conclusions: This is the first study to evaluate the colonization patterns of gas-forming coliforms in colicky infants and healthy controls identified by molecular methods. Coliform bacteria, particularly Escherichia coli, were found to be more abundant in colicky infants. Our data could help to shed light on the cause of infantile colic.