Comparison of oral micro-flora in caries active and caries free Indian children using culture techniques and PCR analysis.

BACKGROUND AND AIMS: Although Streptococcus mutans has been implicated as the major etiologic agent in the development of dental caries, however, this organism has not been found to be present in all children with caries. Thus it remains to be elucidated whether a single or specific consortium of bacteria is responsible for the caries process. The aim of this study is to evaluate the oral microflora of Indian children suffering from dental caries and to compare the same in children with no caries. METHODS: The study was carried out on 67 out-patient 2-14 years old children who reported to the department of Paediatric Dentistry. Dental plaque samples from superficial and deep carious lesions and caries free surfaces in caries active children (n = 35) were collected using a sterile excavator in storage vials and subjected to various conventional and molecular microbial techniques. Caries free children (n = 32), who did not have any carious lesion served as controls. The data obtained was subjected to Pearson's Chi Square/Fischer's Exact tests to determine the statistical difference between the microflora of groups. RESULTS: Main organisms isolated were: Streptococcal species mainly S anginosus, S salivarius, S gordonii: Lactobacilli spp; Coagulase negative Staphylococci, Staph epidermidis, Staph aureus. Other organisms such as Klebsiella spp, Acinetobacter, Enterococcus, E coli could also be found. There was a statistical difference in the frequency of isolation of non-mutans Streptococcal species (P = 0.008) and Lactobacilli species (P = 0.0001) in the two groups. CONCLUSIONS: The study suggests that caries activity in this population of children is associated with a diverse microbial flora without detectable S mutans. Main organisms associated with dental caries in this population are: Gram-positive cocci and bacilli mainly the non-mutans Streptococcus and Lactobacilli. Frequent consumption of sugar containing food promotes the presence and growth of cariogenic organisms.

Role of Mycoplasma pneumoniae infection in acute exacerbations of chronic obstructive pulmonary disease.

Eighty per cent of the cases of acute exacerbation of chronic obstructive pulmonary disease (AECOPD) have an infective aetiology, atypical bacteria including Mycoplasma pneumoniae accounting for 5-10 % of these. However, the importance of association of M. pneumoniae with episodes of AECOPD still remains doubtful. The present study was therefore undertaken to delineate the extent of involvement of M. pneumoniae in patients with AECOPD at a referral hospital in Delhi, India. Sputum samples and throat swabs from a total of 100 AECOPD patients attending the Clinical Research Center of Vallabhbhai Patel Chest Institute, Delhi, were collected during a 2-year period (January 2004-June 2006). The samples were investigated for the presence of aerobic bacterial pathogens and M. pneumoniae. Diagnosis of infection with M. pneumoniae was based on culture, serology, direct detection of M. pneumoniae specific antigen and PCR. Bacterial aetiology could be established in 16 of the 100 samples studied. Pseudomonas spp. were recovered from eight cases, Streptococcus pneumoniae from four and Klebsiella spp. from two cases. Acinetobacter sp. and Moraxella catarrhalis were isolated from one case each. Serological evidence of M. pneumoniae infection and/or detection of M. pneumoniae specific antigen were seen in 16 % of the cases. One case with definite evidence of M. pneumoniae infection also had coinfection with Pseudomonas spp. However, no direct evidence of M. pneumoniae infection was found in our study population as defined by culture isolation or PCR. In conclusion, although the serological prevalence of M. pneumoniae infection in our study population was significantly higher than in the control group, there was no direct evidence of it playing a role in AECOPD.