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Osteomyelitis ppt for healthcare students

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Subhash Karna
Subhash Karna

Microbiological perspectives of osteomyelitis

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Osteomyelitis Dr. Subhash Lal Karn, PhD Associate Professor Dept. of Microbiology NGMC, Chisapani
Introduction Osteomyelitis is an inflammation or swelling of bone tissue that is usually the result of an infection. It may remain localized, or it may spread through the bone to involve the marrow, cortex, periosteum, and soft tissue surrounding the Osteomyelitis may occur as a result of a bacterial bloodstream infection, sometimes called bacteremia, or sepsis, that spreads to the bone. This type is most common in infants and children and usually affects their long bones like the femur (thighbone) or humerus (upper arm bone). When osteomyelitis affects adults, it often involves the vertebral bones along the spinal column.
Classification Attempts to classify are based on (1) the duration and type of symptoms (2)the mechanism of infection (3)the type of host response
Osteomyelitis Acute: <2weeks Early acute Late acute(4- 5days) Subacute: 2weeks 6weeks Less virulent more immune Chronic: >6 weeks Based on the duration and type of symptoms
Classified according to mechanism Osteomyelitis may be 1. Exogenous(trauma, surgery (iatrogenic), or a contiguous infection) 2. Hematogenous (bacteremia)
Single pathogenic organism hematogenous osteomyelitis, Multiple organisms direct inoculation or contiguous focus infection. Staphylococcus aureus ---most commonly isolated pathogen. gram-negative bacilli and anaerobic organisms are also frequently isolated In infants: Staphylococcus aureus Streptococcus agalactiae Escherichia coli In children over one year of age: Staphylococcus aureus, Streptococcus pyogenes Haemophilus influenzae1 Staphylococcus aureus is common organism isolated.2 Etiology 1.Song KM, Sloboda JF. Acute hematogenous osteomyelitis in children. J Am Acad Orthop Surg. 2001;9:166-75 2.Lew DP, Waldvogel FA. Osteomyelitis. N Engl J Med. 1997;336:999-1007
Organism Staphylococcus aureus Coagulase-negative staphylococci or Propionibacterium species Enterobacteriaceae species orPseudomonas aeruginosa Streptococci or anaerobic bacteria Salmonella species orStreptococcus pneumoniae Comments Organism most often isolated in all types of osteomyelitis Foreign-bodyassociated infection Common in nosocomial infections and punchured wounds Associated with bites, fist injuries caused by contact with another persons mouth, diabetic foot lesions, decubitus ulcers Sickle cell disease Organisms Isolated in Bacterial Osteomyelitis Lew DP, Waldvogel FA. Osteomyelitis. N Engl J Med 1997;336:999-1007.
Rare organisms Isolated in Bacterial Osteomyelitis Bartonella henselae Pasteurella multocida or Eikenella corrodens Aspergillus species, Mycobacterium avium- intracellulare or Candida albicans Mycobacterium tuberculosis Brucella species, Coxiella burnetii (cause of chronic Q fever) or other fungi found in specific geographic areas Human immunodeficiency virus infection Human or animal bites Immunocompromised patients Populations in which tuberculosis is prevalent. Population in which these pathogens are endemic
Why staphylococcus most common? S.aureus and S.epidermis ----- elements of normal skin flora S.aureus -----increased affinity for host proteins (traumatised bone) Enzymes (coagulase, surface factor A) ----- hosts immune response . Inactive L forms ------dormant for years Biofilm (polysaccharide slime layer) ---- increases bacterial adherence to any substrate . Large variety of adhesive proteins and glycoproteins ----- mediate binding with bone components.
Epidemiology The number of cases of osteomyelitis involving long bones is decreasing while the rate of osteomyelitis at all other sites remained the same4. The prevalence of Staphylococcus aureus infections is also decreasing, from 55% to 31%, over the twenty-year time period4. The incidence of osteomyelitis due to direct inoculation or contiguous focus infection is increasing due to5: motor-vehicle accidents the increasing use of orthopaedic fixation devices total joint implants. Males have a higher rate of contiguous focus osteomyelitis than do females5. 4. Blyth MJ, Kincaid R, Craigen MA, Bennet GC. The changing epidemiology of acute and subacute haematogenous osteomyelitis in children. J Bone Joint Surg Br. 2001;83:99-102. 5.Gillespie WJ. Epidemiology in bone and joint infection. Infect Dis Clin North Am. 1990;4:361-76.
Pathogenesis: Direct inoculation of microorganisms into bone penetrating injuries and surgical contamination are most common causes Hematogenous spread usually involves the metaphysis of long bones in children or the vertebral bodies in adults Osteomyelitis Microorganisms in bone Contiguous focus of infection seen in patients with severe vascular disease.
Pathogenesis: Host Factors
Bacterial factors: Formation of a glycocalyx surrounding the infecting organisms. protects the organisms from the action of phagocytes and prevents access by most antimicrobials. A surface negative charge of devitalized bone or a metal implant promotes organism adherence and subsequent glycocalyx formation.
Pathology: Hematogenous osteomyelitis: occurs in children < 15 years of age although adults can have this disease occurs in the metaphysis of the long bones. In metaphysis decreased activity of macrophages Frequent trauma Precarious blood supply Diaphysial osteomyelitis : Earlier metaphysis but due to growth becomes diaphyseal mostly in children. Direct trauma to diaphysis Tubercular
Pathology: sharp hairpin turns flow becomes considerably slower and more turbulent
Pathology These are end-artery branches of the nutrient artery Obstruction Avascular necrosis of bone tissue necrosis, breakdown of bone acute inflammatory response due to infection Squestra formation Chronic osteomyelitis
Pathology: Pathologic features of chronic osteomyelitis are : The presence of sclerotic, necrotic piece of bone usually cortical surrounded by radiolucent inflammatory exudate and granulation tissue known as sequestrum. Features: Dead piece of bone Pale Inner smooth ,outer rough Surrounded by infected granulation tissue trying to eat it Types- ring(external fixator) tubular/match-stick(sickle) coke and rice grain(TB) Feathery(syphilis) Colored(fungal) Annular(amputation stumps)
local signs calor, rubor, dolor, tumor Heat, red, pain or tenderness, swelling Initially, the lesion is within the medually cavity, there is no swelling, soft tissue is also normal. The merely sign is deep tenderness. Localized finger-tip tenderness is felt over or around the metaphysis. it is necessary to palpate carefully all metaphysic areas to determine local tenderness, pseudoparalysis
Clinical features During the period of inactivity, no symptoms are present. Only Skin-thin, dark, scarred, poor nourished, past sinus, an ulceration that is not easily heal Muscles-wasting contracture, atrophy Joint-stiffness Bone-thick, sclerotic, often contains abscess cavity
Laboratory findings The white blood cell count will show a marked leucocytosis as high as 20,000 or more The blood culture demonstrates the presence of bacteremia, the blood must be taken when the patient has a chill, especially when there is a spiking temperature. Aspiration. The point of maximal tenderness should be aspirated with a large-bore needle. The thick pus may not pass through the needle. Any material aspirated should be gram stained and cultured to determine the sensitivity to antibiotics.
Microbiology : Best samples are tissue fragments directly from center of infection. If possible, culture specimens should be obtained before antibiotics are initiated. The empiric regimen should be discontinued for three days before the collection of samples for cultures.a Cultures of specimens from the sinus tract are not reliable for predicting which organisms will be isolated from infected bone. a.Ericsson HM, Sherris JC. Antibiotic sensitivity testing. Report of an international collaborative study. Acta Pathol Microbiol Scand [B] Microbiol Immunol. 1971;217(Suppl 217):1-90.
Microbiology : Improved techniques for processing purulent materials: A lysis-centrifugation technique Mild ultrasonication removes hardware to provide optimal bacterial removal. Polymerase chain reaction Used in the diagnosis of bone infection due to unusual or difficult pathogens, such as Mycoplasma pneumoniae Brucella species Bartonella henselae, Both tuberculous and nontuberculous mycobacterium species.
X-ray findings X-ray films are negative within 1-2 weeks Careful comparison with the opposite side may show abnormal soft tissue shadows. It must be stressed that x-ray appearances are normal in the acute phase. There are little value in making the early diagnosis. By the time there is x-ray evidence of bone destruction, the patient has entered the chronic phase of the disease.
Diagnosis: Microbiological diagnosis of osteomyelitis involves: Blood Cultures: To identify the causative organism if the infection is hematogenous spread. Bone Biopsy: Direct sampling of infected bone tissue is crucial for identifying the specific pathogen(s) involved and determining antibiotic susceptibility. Imaging: Radiological techniques like MRI or CT scans can help visualize bone changes and guide the selection of biopsy sites.
Antimicrobial Therapy: Treatment of osteomyelitis typically involves prolonged antibiotic therapy based on the identified pathogen and its antibiotic sensitivity profile. Initial empiric therapy often targets Staphylococcus aureus due to its high prevalence. However, adjustments are made based on culture results. Chronic Osteomyelitis: Chronic osteomyelitis poses additional challenges due to the formation of biofilms by bacteria, which can resist antibiotic treatment and evade immune responses. Surgical intervention to remove infected tissue and improve antibiotic penetration may be necessary.
Prevention: Prevention strategies include appropriate antibiotic prophylaxis for high-risk surgeries or procedures, meticulous wound care, and management of underlying conditions that predispose individuals to infections. Understanding the microbiological aspects of osteomyelitis is crucial for effective management, including accurate diagnosis, targeted antimicrobial therapy, and prevention of recurrent infections.
Long-term Considerations for Osteomyelitis Osteomyelitis requires long-term care to prevent further complications, including care to prevent the following: Fractures of the affected bone Stunted growth in children (if the infection has involved the growth plate) Gangrene in the affected area
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Osteomyelitis ppt for healthcare students

  • 1. Osteomyelitis Dr. Subhash Lal Karn, PhD Associate Professor Dept. of Microbiology NGMC, Chisapani
  • 2. Introduction Osteomyelitis is an inflammation or swelling of bone tissue that is usually the result of an infection. It may remain localized, or it may spread through the bone to involve the marrow, cortex, periosteum, and soft tissue surrounding the Osteomyelitis may occur as a result of a bacterial bloodstream infection, sometimes called bacteremia, or sepsis, that spreads to the bone. This type is most common in infants and children and usually affects their long bones like the femur (thighbone) or humerus (upper arm bone). When osteomyelitis affects adults, it often involves the vertebral bones along the spinal column.
  • 3. Classification Attempts to classify are based on (1) the duration and type of symptoms (2)the mechanism of infection (3)the type of host response
  • 4. Osteomyelitis Acute: <2weeks Early acute Late acute(4- 5days) Subacute: 2weeks 6weeks Less virulent more immune Chronic: >6 weeks Based on the duration and type of symptoms
  • 5. Classified according to mechanism Osteomyelitis may be 1. Exogenous(trauma, surgery (iatrogenic), or a contiguous infection) 2. Hematogenous (bacteremia)
  • 6. Single pathogenic organism hematogenous osteomyelitis, Multiple organisms direct inoculation or contiguous focus infection. Staphylococcus aureus ---most commonly isolated pathogen. gram-negative bacilli and anaerobic organisms are also frequently isolated In infants: Staphylococcus aureus Streptococcus agalactiae Escherichia coli In children over one year of age: Staphylococcus aureus, Streptococcus pyogenes Haemophilus influenzae1 Staphylococcus aureus is common organism isolated.2 Etiology 1.Song KM, Sloboda JF. Acute hematogenous osteomyelitis in children. J Am Acad Orthop Surg. 2001;9:166-75 2.Lew DP, Waldvogel FA. Osteomyelitis. N Engl J Med. 1997;336:999-1007
  • 7. Organism Staphylococcus aureus Coagulase-negative staphylococci or Propionibacterium species Enterobacteriaceae species orPseudomonas aeruginosa Streptococci or anaerobic bacteria Salmonella species orStreptococcus pneumoniae Comments Organism most often isolated in all types of osteomyelitis Foreign-bodyassociated infection Common in nosocomial infections and punchured wounds Associated with bites, fist injuries caused by contact with another persons mouth, diabetic foot lesions, decubitus ulcers Sickle cell disease Organisms Isolated in Bacterial Osteomyelitis Lew DP, Waldvogel FA. Osteomyelitis. N Engl J Med 1997;336:999-1007.
  • 8. Rare organisms Isolated in Bacterial Osteomyelitis Bartonella henselae Pasteurella multocida or Eikenella corrodens Aspergillus species, Mycobacterium avium- intracellulare or Candida albicans Mycobacterium tuberculosis Brucella species, Coxiella burnetii (cause of chronic Q fever) or other fungi found in specific geographic areas Human immunodeficiency virus infection Human or animal bites Immunocompromised patients Populations in which tuberculosis is prevalent. Population in which these pathogens are endemic
  • 9. Why staphylococcus most common? S.aureus and S.epidermis ----- elements of normal skin flora S.aureus -----increased affinity for host proteins (traumatised bone) Enzymes (coagulase, surface factor A) ----- hosts immune response . Inactive L forms ------dormant for years Biofilm (polysaccharide slime layer) ---- increases bacterial adherence to any substrate . Large variety of adhesive proteins and glycoproteins ----- mediate binding with bone components.
  • 10. Epidemiology The number of cases of osteomyelitis involving long bones is decreasing while the rate of osteomyelitis at all other sites remained the same4. The prevalence of Staphylococcus aureus infections is also decreasing, from 55% to 31%, over the twenty-year time period4. The incidence of osteomyelitis due to direct inoculation or contiguous focus infection is increasing due to5: motor-vehicle accidents the increasing use of orthopaedic fixation devices total joint implants. Males have a higher rate of contiguous focus osteomyelitis than do females5. 4. Blyth MJ, Kincaid R, Craigen MA, Bennet GC. The changing epidemiology of acute and subacute haematogenous osteomyelitis in children. J Bone Joint Surg Br. 2001;83:99-102. 5.Gillespie WJ. Epidemiology in bone and joint infection. Infect Dis Clin North Am. 1990;4:361-76.
  • 11. Pathogenesis: Direct inoculation of microorganisms into bone penetrating injuries and surgical contamination are most common causes Hematogenous spread usually involves the metaphysis of long bones in children or the vertebral bodies in adults Osteomyelitis Microorganisms in bone Contiguous focus of infection seen in patients with severe vascular disease.
  • 13. Bacterial factors: Formation of a glycocalyx surrounding the infecting organisms. protects the organisms from the action of phagocytes and prevents access by most antimicrobials. A surface negative charge of devitalized bone or a metal implant promotes organism adherence and subsequent glycocalyx formation.
  • 14. Pathology: Hematogenous osteomyelitis: occurs in children < 15 years of age although adults can have this disease occurs in the metaphysis of the long bones. In metaphysis decreased activity of macrophages Frequent trauma Precarious blood supply Diaphysial osteomyelitis : Earlier metaphysis but due to growth becomes diaphyseal mostly in children. Direct trauma to diaphysis Tubercular
  • 15. Pathology: sharp hairpin turns flow becomes considerably slower and more turbulent
  • 16. Pathology These are end-artery branches of the nutrient artery Obstruction Avascular necrosis of bone tissue necrosis, breakdown of bone acute inflammatory response due to infection Squestra formation Chronic osteomyelitis
  • 17. Pathology: Pathologic features of chronic osteomyelitis are : The presence of sclerotic, necrotic piece of bone usually cortical surrounded by radiolucent inflammatory exudate and granulation tissue known as sequestrum. Features: Dead piece of bone Pale Inner smooth ,outer rough Surrounded by infected granulation tissue trying to eat it Types- ring(external fixator) tubular/match-stick(sickle) coke and rice grain(TB) Feathery(syphilis) Colored(fungal) Annular(amputation stumps)
  • 18. local signs calor, rubor, dolor, tumor Heat, red, pain or tenderness, swelling Initially, the lesion is within the medually cavity, there is no swelling, soft tissue is also normal. The merely sign is deep tenderness. Localized finger-tip tenderness is felt over or around the metaphysis. it is necessary to palpate carefully all metaphysic areas to determine local tenderness, pseudoparalysis
  • 19. Clinical features During the period of inactivity, no symptoms are present. Only Skin-thin, dark, scarred, poor nourished, past sinus, an ulceration that is not easily heal Muscles-wasting contracture, atrophy Joint-stiffness Bone-thick, sclerotic, often contains abscess cavity
  • 20. Laboratory findings The white blood cell count will show a marked leucocytosis as high as 20,000 or more The blood culture demonstrates the presence of bacteremia, the blood must be taken when the patient has a chill, especially when there is a spiking temperature. Aspiration. The point of maximal tenderness should be aspirated with a large-bore needle. The thick pus may not pass through the needle. Any material aspirated should be gram stained and cultured to determine the sensitivity to antibiotics.
  • 21. Microbiology : Best samples are tissue fragments directly from center of infection. If possible, culture specimens should be obtained before antibiotics are initiated. The empiric regimen should be discontinued for three days before the collection of samples for cultures.a Cultures of specimens from the sinus tract are not reliable for predicting which organisms will be isolated from infected bone. a.Ericsson HM, Sherris JC. Antibiotic sensitivity testing. Report of an international collaborative study. Acta Pathol Microbiol Scand [B] Microbiol Immunol. 1971;217(Suppl 217):1-90.
  • 22. Microbiology : Improved techniques for processing purulent materials: A lysis-centrifugation technique Mild ultrasonication removes hardware to provide optimal bacterial removal. Polymerase chain reaction Used in the diagnosis of bone infection due to unusual or difficult pathogens, such as Mycoplasma pneumoniae Brucella species Bartonella henselae, Both tuberculous and nontuberculous mycobacterium species.
  • 23. X-ray findings X-ray films are negative within 1-2 weeks Careful comparison with the opposite side may show abnormal soft tissue shadows. It must be stressed that x-ray appearances are normal in the acute phase. There are little value in making the early diagnosis. By the time there is x-ray evidence of bone destruction, the patient has entered the chronic phase of the disease.
  • 24. Diagnosis: Microbiological diagnosis of osteomyelitis involves: Blood Cultures: To identify the causative organism if the infection is hematogenous spread. Bone Biopsy: Direct sampling of infected bone tissue is crucial for identifying the specific pathogen(s) involved and determining antibiotic susceptibility. Imaging: Radiological techniques like MRI or CT scans can help visualize bone changes and guide the selection of biopsy sites.
  • 25. Antimicrobial Therapy: Treatment of osteomyelitis typically involves prolonged antibiotic therapy based on the identified pathogen and its antibiotic sensitivity profile. Initial empiric therapy often targets Staphylococcus aureus due to its high prevalence. However, adjustments are made based on culture results. Chronic Osteomyelitis: Chronic osteomyelitis poses additional challenges due to the formation of biofilms by bacteria, which can resist antibiotic treatment and evade immune responses. Surgical intervention to remove infected tissue and improve antibiotic penetration may be necessary.
  • 26. Prevention: Prevention strategies include appropriate antibiotic prophylaxis for high-risk surgeries or procedures, meticulous wound care, and management of underlying conditions that predispose individuals to infections. Understanding the microbiological aspects of osteomyelitis is crucial for effective management, including accurate diagnosis, targeted antimicrobial therapy, and prevention of recurrent infections.
  • 27. Long-term Considerations for Osteomyelitis Osteomyelitis requires long-term care to prevent further complications, including care to prevent the following: Fractures of the affected bone Stunted growth in children (if the infection has involved the growth plate) Gangrene in the affected area