bacteria Flashcards
What bacteria is found in healthy gingivae?
Gram positive rods and cocci
Facultatively anaerobic or aerobic
Eg - streptococci and Actinomyces
What kind of bacteria is found in periodontitis?
Predominately gram negative rods and spirochetes
Eg - A.a, P. gingivalis, T. denticola and T. forsythia
What kind of bacteria is found in gingivitis?
Gram positive cocci decrease and gram negative anaerobics increase
Eg - fusobacterium and actinomyces
What bacteria make up the red complex?
T. denticola
T. forsythia
P. gingivalis
Describe T. denticola and explain its virulence factor
Gram negative anaerobe
Spirochete
Able to adhere to epithelial cells, releasing damaging enzymes into their ECM
Describe T. forsythia and explain its virulence factor
Gram negative
Anaerobe
Spirilla (spindle shaped)
Cell surface proteoglycans enzymes
Describe P. gingivalis and explain its virulence factors
Gram negative
Rod shaped
Anaerobe
Produces colleganase enzyme which breaks down collagen in periodontal tissues
Degrades haemoglobin which releases iron preventing iron transport
Describe fusobacterium nucleatum and explain its virulence factors
Gram negative
Anaerobic
Non motile
Cigazrette shaped bacilli with sharp pointed ends
Adhesin A - allow for other species to adhere to and colonise a host tissue they otherwise couldn’t
Endotoxin
Describe Aa and explain its virulence factors
Gram negative
Capnophilic
Coccobacilus
Produces leukotoxin which can kill WBCs by forming pores causing its contents to be released
What are virulence factors?
Mechanisms used by pathogens to cause damage to host tissued
How does the innate immune system response act against the biofilm?
Intact epithelium - physical Barrie’s
Saliva - antimicrobial effect via salivary IgA, lactoferrin, salivary peroxidases and lysozyme
GCF - washes out non-adherent bacteria
Cellular component - includes neutrophils and macrophages
How does the adaptive immune response act against the biofilm?
B cells produce antibodies that neutralise bacterial toxins and tag bacteria for destruction
T-helper cells produce cytokines, assist in the differentiation of B cells and activate neutrophils and macrophages
What bacteria causes necrotising periodontal diseases?
Fusiform and spirochaetal bacteria
