Microbiology of Odontogenic Bacteremia

By:Aleesha AttarGovt.Dental College & Hosp,Mumbai

Bacteremia is the presence of viable bacterias in the blood stream.

Transient bacteremia

Septicemia

Introduction

Culture Independent: 16S rRNA gene sequencing -6 Billion bacteria.

-700 Species-9 different phyla

Some 30% to 40% of the bacteria normally residing in the human mouth yet to be identified.

The bacterial flora of the mouth exhibits commensalism.

Yet these commensal residents of the human body have the ability to become pathogenic in the events of traslocation to a different niche.

Oral commensals residing in periodontal niches commonly exist in the form of biofilm communities.

On non-shedding surfaces the teeth or prosthesis or shedding surface, such as the epithelial linings of gingival crevices or periodontal pockets.

Oral bacterial biofilm, particularly the sub- gingival plaque bio-film, is its close proximity to a highly vascularized milieu.

This environment is different from other sites where bacteria commonly reside in the human body.

This environment is different from other sites where bacteria commonly reside in the human body.

Innate defense by polymorphonuclear neutrophils is highly developed at the dentogingival junction and backed up by a highly organized lymphatic system.

The oral biofilms, is left undisturbed can established themselves permanently on non- shedding tooth surfaces subjacent to the dentogingival junction.

Any disruption of the natural intergrity between the bio film and the subgingival epithelium, could led to a bacteremic state.

Inflammatory conditions such as in gingivitis and chronic periodontitis, the periodontal vasculature poliferates and dilates which facilitates the entry of microbesin bloodstreams.

Often, these bacteremias are short lived and transient .

On occasions, these micro-organisms may affect other target organs leading to subclinical, acute or chronic infections.

Bacterial Endocarditis is a well known example of this.

Bacterias gain entry from the oral niches into the bloodstream through number of mechanisms and variety of portals.

Tissue trauma such as in Periodontal probing Scaling Instrumentation beyond root apex Tooth extraction

may lead to spillage of bacteria in bloodstream.

Bacterial entry into the bloodstream

Individuals with poor oral hygiene are at greater risk during oral manipulative procedures.

Only few species are detected in bloodstream inspite of multitude of diverse bacteria.

Species that are commonly found in bloodstream have virulence attributes such as

Endothelial adhesion of STREPTOCOCCUS SPP. Degardation of Intercellular matrices by

PORPHYROMONAS GINGIVALIS Phagocytic activity by AGGRETIBACTER

ACTINOMYCETEMCOMINTANS.

1. To evaluate the evidence based on triggering mechanisms & other predisposing factors that lead to Odontogenic bacteremia.

2. To determine the diversity and freq. of causative bacterial species in relation to oral manipulative procedure.

3. To assess the role of odontogenic bacteremia as causative factor in systemic and end organs infection.

Objectives

Researches have shown that people with periodontal gum disease & infections were more prone to bacteremias.

Cobe’s findings indicated highest incidence in periodontal cleaning(40%)

Exodontia (35%) Brushing (24%) Hard mastication (Chewing hard candy) (17%)

Historical Perspective

Any disruption to the bacterial biofilms within gingival niche leads to dissemination of organisms.

Not only oral procedures but routine oral hygiene activities such as brushing, flossing, chewing can be disruptive.

Poor fabricated appliances used in oral manipulative procedure can also lead to bacteremia.

Triggering factors

17% of the subjects who chewed hard candy(mastication) developed bacteremia, while none was detected with gentle mastication.

Bacteremia was detected in 20% of subjects who had evidence of periodontal inflammation, while none was detected in periodontally healthy subjects and subjects with gingivitis.

Chewing

Raised levels of bacterial endotoxins in subjects with Chronic periodontitis, as assessed by the Limulus amoebocyte lysate assay also lead to bacteremia.

According to the researches, it appears that in adult with a healthy periodontium, brushing is not a significant factor contributing to systemic bacterial dessimantion from the mouth.

Subjects wearing orthodontic appliances demonstrated bacteremias of odontogenic origin following tooth brushing, with an incidence of 25%

Personal Oral Hygiene Measures

Dental Flossing could mechanically disturb the periodontal plaque biofilms, but no significant bacteremia was detected with daily flossing, even in gingivitis.

Various degrees of bacterial dissemination are associated with periodontal probing, root planning and subgingival irritation.

The presence inflammation in the periodontal site is an imp. contributory factor.

The inflammation associated with gingivitis can be less than that with periodontitis.

Periodontal procedures

Subgingival irrigation with antiseptics such as chlorhexidine prior to scaling is practised by some dental surgeons.

There is some evidence that the bacteremic incidence does drop with continuous & regular rinsing with chlorhexidine or povidone-iodine.

Use of diode laser as an adjunct to ultrasonic scaling has attributed to the lesser degree of tissues trauma.

Exodontia and associated tissue trauma cause bacteremia and this is by far the most studied oral surgical procedure evaluated to assess odontogenic bacteremias.

Any minor surgical intervention bacteremic incidence appear to be influence positively by the presence of gingivitis, periodontitis.

Tooth extraction

When in surgical incision of particularly third molar with subsequent insertion of suture nearly 10% of individual had bacteremia.

There is no change in the incidence of bacteremia with increase number of teeth extracted

Pre and perioperative admistration of antimicobacterial agent such as clindyamysin, erythromysin,josamysin and cefaclor

Only few procedure related to exodontia appear to reduce bacteremia such as preoperative admistration of antibacterial agent

Example amoxicilline cifuroxime and maxifloxacin that reduce bacteremia.

If the bacteremia occur before tooth extraction so will require povidone iodine most potent incidence reduce bacteremia.

Insertion of orthodontics appliance involve manipulation of oral tissue ,particularly teeth and gingiva .

This may lead systematic bacterial dissemination .

Orthodontics procedure such as alginate impression debonding removal of fixed appliances,appear to produce no significant bacteremia

Orthodontics procedure

It is likely that endodontic procedure that entail instrumentation of the pulp chamber of either single or multiple root canal of teeth.

Reamers or broches may introduce bacteria into the periapical vasculature of teeth.

Incidence of bacteria was reportedly higher when the reamers reaches beyond the root canal.

Endodontic procedure

The procedure commonly carried out by specialist in oral medicine for imaging of salivary glands called Sialography.

Bacteremia of streptococcal origin have been observed by some workers during the different stages of such procedures.

Misc. Oral Procedures

Dentoalveolar abscess are known to induce inflammation & vascular poliferation essentially at periapical region of tooth.

Two major parameters :1.Degree of Inflammation

2.Amount of tissue trauma

Odontogenic bacteremias are temporary in nature.

Bacterias are removed from blood stream relatively quickly by

1) INNATE DEFENCE MECHANISM2) ADAPTIVE DEFENCE MECHANISM Any system can be affected by spread

infection from oral cavity.

Temporal Nature of Odontogenic Bacteremia

CNS – enclosed in anatomical & functional covering.

Blood brain barrier. Bacterias can enter into CNS thr’ blood

brain barrier. Or can directly ascend to the brain.

Systemic Infections With Oral Bacteria

Not as frequent as CNS Oral bacterias cause sacroiliitis i.e.

inflammation of the sacroiliac joint , acute osteomyelitis i.e. inflammation of bone.

Potential triggering factors for these infections are

1. Periodontitis2. Tooth extraction3. Ultrasonic scaling

Skeletal Infections

Bacteria can translocate into the lungs thr’ direct anatomical routes.

but Involment of more than one lung Multiplicity of lesions Nature of the organisms

favour oral hematogenous spread.

Such episodes are result of spread from an oral niches due to the poor oral hygiene

Respiratory Infections

30

Selenomonas spp. Viridans group streptococci Streptococcus Intermedius Actinomyces Odontolyticus

Have been involved in1.Acute respiratory Syndrome2.Lung abscesses

Adverse pregnancy outcomes such as preterm birth or premature rupture of membranes are associated with poor maternal oral hygiene.

Syphilitic spirochete treponema pallidum crosses the fetoplacental barrier , results in neonatal syphillis and associated dental abnormalities.

Thus oral bacteria may affect the feotus through fetoplacantal passage.

Infections in Pregnancy

Standard technique: INVITRO CULTURES

Various procedure of diagnosing Automated blood culture system (Bactec

System) Lysis filteration method Activity profile Indices Test (API Test) Molecular Probe-based identification method

Diagnosing the source of bacteremia

Origin or source detection is based on Phenotypic Comparison

Biochemical profiles Chromatographic evidences of Macromolecule SDSC gel electrophoresis

Genotypic Comparison Pulse field gel electrophoresis of genomic DNA. & Ribotyping Or 16S rRNA sequencing.

There is a large diversity of bacterias in oral niches only few has been isolated from blood cultures.

A large portion of this diversity is occupied by the members of Frimicutus family and large proportion of genus Streptococcus.

Bacterial Diversity in Oral Cavity

Various types of organisms like Pigmented and Non pigmented: Aerobic,

Californo, Proteus, Lactobacillus,etc Anaerobic, micrococci: Nisseria, actinomyces

leptothrix, mycoplasma, etc Fungi: Candida & Geotrichum

Initially at birth the microbials of our oral cavity is similar to the mother’s vagina which later replaced by bacterias as present in mother’s mouth.

Normal Flora of mouth

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