Screening for subgingival occurrence of gram-negative enteric rods in periodontally diseased and healthy subjects

Presence of non-oral bacteria in the oral cavity

A homeostatic balance exists between the resident microbiota in the oral cavity and the host. Perturbations of the oral microbiota under particular conditions can contribute to the growth of non-oral pathogens that are hard to kill because of their higher resistance to antimicrobials, raising the probability of treatment failure and reinfection. The presence of these bacteria in the oral cavity has been proven to be associated with several oral diseases such as periodontitis, caries, and gingivitis, and systemic diseases of importance in clinical medicine such as cystic fibrosis, HIV, and rheumatoid arthritis. However, it is still controversial whether these species are merely transient members or unique to the oral cavity. Mutualistic and antagonistic interactions between the oral microbiota and non-oral pathogens can also occur, though the mechanisms used by these bacteria are not clear. Therefore, this review presents an overview of the current knowledge about the presence of non-oral bacteria in the oral cavity, their relationship with systemic and oral diseases, and their interactions with oral bacteria.

Prevalence of herpesviruses in periodontal disease of the North Indian population: A pilot study

Introduction:

Periodontitis is a multifactorial disease of diverse microbiome, predominantly bacterial. Bacterial infection alone may not explain complete pathophysiology and clinical variations in disease pattern. Concept of herpesviruses playing a significant role in periodontal pathogenesis has been explored globally. Studies show varied results and difference may be accounted to variations existing in studied populations. The present study explored the prevalence of herpesviruses in periodontal disease of the North Indian population.

Materials and Methods:

In this case–control study, tissue samples were collected from the normal gingiva (control: n = 48) and deepest pocket (cases: n = 48) using a single curette stroke. Periodontal disease status was assessed through the gingival index, pocket depth, and clinical attachment level which were compared to viral marker positivity.

Results:

Ninety samples from 48 healthy gingiva and 48 periodontitis patients were assessed between the age range of 17–60 years. The prevalence of cytomegalovirus was 2.083% (cases) and 2.083% (controls) and Epstein–Barr virus (EBV) was 18.75% (cases) and 0% (controls). Odd's ratio for EBV in patients with periodontitis is calculated (Haldane–Anscombe correction) to be 21.82%. Herpes simplex virus 1/2 and varicella-zoster virus were absent in both groups.

Conclusions:

Within the limitation of this study, EBV was found in cases of periodontitis patients. Its role in disease initiation and progression is not clear. Further studies are required to ascertain EBV as risk factor in periodontal disease.

Non-oral, aerobic, Gram-negative bacilli in the oral cavity of Thai HIV-positive patients on Highly-active anti-retrovirus therapy medication

In the present study, we identified and evaluated the antibiotic susceptibility of 96 independent, aerobic, Gram-negative bacillus isolates from 255 Thai HIV-positive adults who were on Highly-active anti-retrovirus therapy (HAART) medication. Another 46 isolates from HIV non-HAART individuals, vertically transmitted HIV-positive individuals, and non-HIV controls were included for comparison. A total of 103 strains were tested for antibiotic susceptibility using disc diffusion for screening and E-test for minimal inhibitory concentration determination, with special attention on extended-spectrum beta-lactamase (ESBL) isolates. Pseudomonas aeruginosa, Pseudomonas luteola, Burkholderia cepacia, Aeromonas hydrophila, Klebsiella, and Enterobacter species were the most common bacteria. All strains were resistant against penicillin, amoxicillin, clindamycin, and metronidazole. No ESBL isolates were found.

Subgingival prevalence rate of enteric rods in subjects with periodontal health and disease

BACKGROUND

The prevalence of enteric rods and their association with chronic periodontitis has gained prominence recently. Although the prevalence of these organisms from the subgingival plaque sample was reported in the literature, the carriage rate of these rods in our population is lacking. The present study was undertaken to know the carriage rate of enteric rods from our population in patients with periodontal health and disease.

MATERIALS AND METHODS

Eighty-four systemically healthy participants, inclusive of 46 males and 38 females, were selected for the study. The selected participants were subjected to a periodontal examination and were categorized into chronic periodontitis and healthy group. Subgingival plaque samples were taken from all the participants, plated onto McConkey agar plates, and incubated overnight at 37° C to check for the growth of organisms. The grown organisms were then cultured according to the standard procedures.

RESULTS

Prevalence of 71% and 83% of enteric rods in subjects with periodontal health and disease, respectively, was found in our study which was not statistically significant.

CONCLUSION

Although no significant differences exist in the prevalence of enteric rods between healthy and patients with chronic periodontitis, the prevalence rate of enteric rods in subgingival plaque samples is considerably high in our population.

Non-oral gram-negative facultative rods in chronic periodontitis microbiota

OBJECTIVE

The subgingival prevalence of gram-negative facultative rods not usually inhabiting or indigenous to the oral cavity (non-oral GNFR), as well as selected periodontal bacterial pathogens, were evaluated by culture in untreated and treated chronic periodontitis patients.

METHODS

Subgingival biofilm specimens from 102 untreated and 101 recently treated adults with chronic periodontitis in the Netherlands were plated onto MacConkey III and Dentaid selective media with air-5% CO2 incubation for isolation of non-oral GNFR, and onto enriched Oxoid blood agar with anaerobic incubation for recovery of selected periodontal bacterial pathogens. Suspected non-oral GNFR clinical isolates were identified to a species level with the VITEK 2 automated system.

RESULTS

A total of 87 (42.9%) out of 203 patients yielded subgingival non-oral GNFR. Patients recently treated with periodontal mechanical debridement therapy demonstrated a greater prevalence of non-oral GNFR (57.4% vs 28.4%, P < 0.0001), and a greater number of different non-oral GNFR species (23 vs 14 different species), than untreated patients. Sphingomonas paucimobilis was the most frequently isolated subgingival non-oral GNFR species. Several GNFR species normally found in animals and human zoonotic infections, and not previously detected in human subgingival biofilms, were recovered from some patients, including Bordetella bronchispetica, Pasteurella canis, Pasteurella pneumotropica and Neisseria zoodegmatis. Porphyromonas gingivalis and Tannerella forsythia were significantly associated with the presence of subgingival non-oral GNFR.

CONCLUSIONS

A surprisingly high proportion of Dutch chronic periodontitis patients yielded cultivable non-oral GNFR in periodontal pockets, particularly among those recently treated with periodontal mechanical debridement therapy. Since non-oral GNFR species may resist mechanical debridement from periodontal pockets, and are often not susceptible to many antibiotics frequently used in periodontal practice, their subgingival presence may complicate periodontal treatment in species-positive patients and increase risk of potentially dangerous GNFR infections developing at other body sites.

Extended-spectrum beta-lactamase-producing bacteria are not detected in supragingival plaque samples from human fecal carriers of ESBL-producing Enterobacteriaceae

BACKGROUND

The prevalence of infections caused by Cefotaximase-Munich (CTX-M)-type extended-spectrum beta-lactamase-producing Enterobacteriaceae (ESBL-E) has rapidly increased during the past 15 years. Enterobacteriaceae are commonly found in the gastrointestinal tract and long-term intestinal carriage is considered important for the spread of ESBL and as a source of clinical infections. Oral biofilm such as supragingival plaque is known to contain numerous antibiotic resistance determinants and may also represent a poorly investigated site for ESBL carriage and further spread.

OBJECTIVE

To investigate possible carriage of ESBL-producing bacteria in supragingival plaque of known fecal carriers of these bacteria.

DESIGN

We screened for the presence of aerobic and anaerobic ESBL-producing bacteria and bla CTX-M in supragingival plaque samples from healthy human adults with culture-verified fecal carriage of CTX-M-producing Escherichia coli. The presence or absence of Enterobacteriaceae and ESBL-producing bacteria in plaque samples was evaluated using culture-based methods and consensus CTX-M PCR.

RESULTS

Oral samples were obtained from 17 participants with known previous carriage of ESBL-producing E. coli. No ESBL-producing bacteria or ESBL genes were detected using culture-based and molecular methods. One colony of Rahnella aquatilis harboring the class A ESBL gene bla RAHN-1/2 was identified in an oral sample from one of the participants.

CONCLUSION

This pilot study supports the notion that the presence of CTX-M-producing bacteria is uncommon in oral plaque of healthy human adult fecal carriers. Due to the limited number of persons tested, a low prevalence of oral ESBL-carriage in healthy adults or carriage in selected groups of patients cannot be excluded. To our knowledge, this is the first description of an R. aquatilis with the RAHN-1/2 gene in the oral cavity.