Genotypic characterization of initial acquisition of Streptococcus mutans in American Indian children

Abstract

BackgroundSevere-early childhood caries (S-ECC) is one of the most common infectious diseases in children and is prevalent in lower socio-economic populations. American Indian children suffer from the highest levels of S-ECC in the United States. Members of the mutans streptococci, Streptococcus mutans, in particular, are key etiologic agents in the development of caries. Children typically acquire S. mutans from their mothers and early acquisition is often associated with higher levels of tooth decay.MethodsWe have conducted a 5-year birth cohort study with a Northern Plains Tribe to determine the temporality and fidelity of S. mutans transmission from mother to child in addition to the genotypic diversity of S. mutans in this community. Plaque samples were collected from 239 mother/child dyads at regular intervals from birth to 36 months and S. mutans were isolated and genotyped by arbitrarily primed-polymerase chain reaction (AP-PCR).ResultsHere we present preliminary findings from a subset of the cohort. The focus for this paper is on initial acquisition events in the children. We identified 17 unique genotypes in 711 S. mutans isolates in our subset of 40 children, 40 mothers and 14 primary caregivers. Twelve of these genotypes were identified in more than one individual. S. mutans colonization occurred by 16 months in 57.5% of the children and early colonization was associated with higher decayed, missing and filled surface (DMFS) scores (p=0.0007). Children colonized by S. mutans shared a common genotype with their mothers 47.8% of the time. While multiple genotypes were common in adults, only 10% of children harbored multiple genotypes.ConclusionThese children acquire S. mutans at an earlier age than the originally described ‘window of infectivity’ and often, but not exclusively, from their mothers. Early acquisition is associated with both the caries status of the children and the mothers.

Genetic Diversity and Evidence for Transmission of Streptococcus mutans by DiversiLab rep-PCR

“…1). The diversity of genotypes observed in this study is generally similar to other large-scale studies of S. mutans using AP-PCR (Lynch, Villhauer, Warren, Marshall, Dawson, Blanchette, Phipps, Starr and Drake, 2015, Palmer, Nielsen, Peirano, Nguyen, Vo, Nguyen, Jackson, Finlayson, Sauerwein, Marsh, Edwards, Wilmot, Engle, Peterson, Maier and Machida, 2012). While some studies have reported more amplitypes with AP-PCR from smaller sample pools, it should be noted in all gel based genotyping studies there is a degree of variability due to interpretation, techniques and conditions employed.…”

“…The total number of children was adjusted for comparison with mothers (n=105) since not all children had mothers participating in the study and 1 child was eliminated because no S. mutans were recovered. The number of genotypes in this study was 1 −9 per child whereas others have reported that children harbor between 1–6 genotypes (Alves, Nogueira, Stipp, Pampolini, Moraes, Goncalves, Hofling, Li and Mattos-Graner, 2009, Cheon, Moser, Whiddon, Osgood, Momeni, Ruby, Cutter, Allison and Childers, 2011, Cheon, Moser, Wiener, Whiddon, Momeni, Ruby, Cutter and Childers, 2013, Domejean, Zhan, DenBesten, Stamper, Boyce and Featherstone, 2010, Liu, Zou, Shang and Zhou, 2007, Lynch, Villhauer, Warren, Marshall, Dawson, Blanchette, Phipps, Starr and Drake, 2015, Pieralisi, Rodrigues, Segura, Maciel, Ferreira, Garcia and Poli-Frederico, 2010). The average number of genotypes per child in this study was 2.7 and is notably higher than what others have reported for children (range 1.5–2.0) (Cheon, Moser, Whiddon, Osgood, Momeni, Ruby, Cutter, Allison and Childers, 2011, Cheon, Moser, Wiener, Whiddon, Momeni, Ruby, Cutter and Childers, 2013, Domejean, Zhan, DenBesten, Stamper, Boyce and Featherstone, 2010, Liu, Zou, Shang and Zhou, 2007, Lynch, Villhauer, Warren, Marshall, Dawson, Blanchette, Phipps, Starr and Drake, 2015).…”

“…The genetic diversity of S. mutans strains has been studied using continually evolving gel based typing methods including randomly amplified polymorphic DNA (RAPD) fingerprinting (Redmo Emanuelsson et al, 2003), arbitrarily primed PCR (AP-PCR) (Baca et al, 2012, Cogulu et al, 2006, Domejean et al, 2010, Gamboa et al, 2010, Gilbert et al, 2014, Hu et al, 2014, Lembo et al, 2007, Li and Caufield, 1998, Liu et al, 2007, Lynch et al, 2015, Napimoga et al, 2004, Palmer et al, 2012, Pieralisi et al, 2010, Teanpaisan et al, 2012, Zhao et al, 2014, Zhou et al, 2011), pulse field gel electrophoresis (PFGE) (Mineyama et al, 2004, Mineyama et al, 2007, Roberts et al, 2002) and repetitive extragenic palindromic PCR (rep-PCR) (Cheon et al, 2011, Moser et al, 2010). Molecular based typing methods used to evaluate genetic diversity include multilocus enzyme electrophoresis (MLEE) (Napimoga, Kamiya, Rosa, Rosa, Hofling, Mattos-Graner and Goncalves, 2004) and more recently, multilocus sequence typing (MLST) (Do et al, 2010, Lapirattanakul et al, 2008, Momeni et al, 2013, Nakano et al, 2007).…”

“…observed indicate limited genetic variation except in the case of MLST, which can be more discriminative than traditional gel based typing methods since a single nucleotide changes can result in a new sequence type (ST). The two most frequently used methods in the literature are AP-PCR and rep-PCR, both of which are currently being used in large-scale epidemiological studies of S. mutans in high-risk communities (Cheon et al, 2013, Lynch, Villhauer, Warren, Marshall, Dawson, Blanchette, Phipps, Starr and Drake, 2015). Genotyping is a valuable tool for epidemiological surveillance of clinical microorganisms, allowing for the efficient investigation of microbial diversity, micro-evolutionary shifts, and transmission tracking.…”

Improved method for rapid and accurate isolation and identification of Streptococcus mutans and Streptococcus sobrinus from human plaque samples

“…Samples were collected and processed as detailed by Lynch et al (2015). Briefly, trained and calibrated dental hygienists collected whole mouth plaque samples from Native American Indian children and their mothers (or primary caregivers) at 8 time points from the child’s birth to age 36 months by swabbing all smooth surfaces of the teeth (oral mucosa and tongues of children prior to tooth eruption).…”