Microbiology of Bone & Joint Infections

1. Microbiologyof Bone & Joint Infections

2. Myositis • Myositis refers to any condition causing inflammation in one or more muscles • Weakness, swelling, and pain are the most common myositis symptoms • Myositis causes include infection, injury, autoimmune conditions, and drug side effects • Treatment of myositis varies according to the cause

3. Causes of Myositis • Myositis is caused by any condition that leads to inflammation in the muscles • Myositis causes can be divided into several major categories: • Inflammatory conditions causing myositis • Myositis caused by microbial infection • Myositis caused by drugs • Myositis due to injury

4. Myositis caused by microbial infection • Known pathogens include the following: • Viral • HIV (one of the most common causes of myositis), HTLV-1, Cytomegalovirus, Coxsackie B virus (epidemic myalgia), Influenza • Bacterial • S. aureus (most common, 70%); Streptococcus viridans; Salmonella enteritidis; Neisseria species , Yersinia species

5. Spirochetal • Borrelia burgdorferi • Mycobacterial • Mycobacterium avium • Parasitic • Echinococcus granulosus, Taenia solium, T. cruzi • Fungal • Cryptococcus neoformans, Candidaspecies,Histoplasmacapsulatum, Aspergillusspecies

6. Symptoms of Myositis • The main symptom of myositis is muscle weakness that may be detectable with testing • Muscle pain (myalgias) • Dermatomyositis, polymyositis • The weakness affects large muscle groups • including the neck, shoulders, hips, and back Dermatomyositis

7. Dermatomyositis

8. The weakness from myositis can lead to falls • make it difficult to get up from a chair or after a fall • Other myositis symptoms that may be present with inflammatory conditions include: • Rash • Fatigue • Thickening of the skin on the hands • Difficulty swallowing • Difficulty breathing

9. Diagnosis of Myositis • Blood tests • Magnetic resonance imaging (MRI scan) • Electromyography (EMG) • Muscle biopsy

10. Osteomyelitis • Osteomyelitis is an infection in a bone • Infections can reach a boneby traveling through thebloodstream or spreadingfrom nearby tissue • Osteomyelitis can also beginin the bone itself if an injuryexposes the bone to germs Osteomyelitis of the tibia of a young child

11. In children • most commonly affects the long bones of the legs and upper arm • In adults • more likely to develop osteomyelitis in the bones that make up the spine • People who have diabetesmay develop osteomyelitisin their feet if they have foot ulcers Plantar foot ulcers with a deep space infection

12. Once considered an incurable condition, osteomyelitis can be successfully treated today • Most people require surgery to remove parts of the bone that have died • followed by strong antibiotics • often delivered intravenously • typically for at least six weeks

13. Symptoms • Signs and symptoms of osteomyelitis include: • Fever or chills • Irritability or lethargy in young children • Pain in the area of the infection • Swelling, warmth and redness over the area of the infection

14. Causes • Most cases of osteomyelitis are caused by staphylococcus bacteria • Germs can enter a bone in a variety of ways, including: • Via the bloodstream • From a nearby infection • Direct contamination

15. Via the bloodstream • Germs in other parts of the body can travel through bloodstream to a weakened spot in a bone • From a nearby infection • Severe puncture wounds can carry germs deep inside the body • If such an injury becomes infected, the germs can spread into a nearby bone

16. Direct contamination • This may occur if a bone have broken so severely that part of it is sticking out through skin • Direct contamination can also occur during surgeries to replace joints or repair fractures

17. Disease causative agent

18. Acute Osteomyelitis • Vertebral osteomyelitis can occur in adults secondary to a UTI or prostatitis • Candidemia from infected central venous catheters can lead to fungal osteomyelitis • Contiguous infection • Bacteria related to primary focus, it includes • Gram positive cocci, Gram negative bacilli, Anaerobes, and Poly-microbial infection

19. Risk factors • Bones are normally resistant to infection • For osteomyelitis to occur, a situation that makes your bones vulnerable must be present • Recent injury or orthopedic surgery • A severe bone fracture or a deep puncture wound • Surgery • Deep animal bites

20. Circulation disorders • When blood vessels are damaged or blocked • What begins as a small cut can progress to a deep ulcer that may expose deep tissue and bone to infection • Diseases that impair blood circulation include • Poorly controlled diabetes • Peripheral arterial disease • often related to smoking • Sickle cell disease Peripheral vascular disease

21. Problems requiring intravenous lines or catheters • Examples of when this type of tubing might be used include • Dialysis machines • Urinary catheters • Long-term intravenous tubing

22. Conditions that impair the immune system • Factors that may suppress your immune system include • Chemotherapy • Poorly controlled diabetes • Having had an organ transplant • Needing to take corticosteroids • For unclear reasons • people with HIV/AIDS don't seem to have an increased risk of osteomyelitis • Illicit drugs • nonsterile needles • unsterilized skin before injections

23. Complications • Osteomyelitis complications may include: • Bone death (osteonecrosis) • Septic arthritis • Impaired growth • Skin cancer Osteonecrosis

24. Tests and diagnosis • Blood tests • Imaging tests • X-rays • Computerized tomography (CT) scan • Magnetic resonance imaging (MRI) • Bone biopsy

25. Treatments and drugs • The most common treatments for osteomyelitis are antibiotics and surgery to remove portions of bone that are infected or dead • Hospitalization is usually necessary

27. Medications • A bone biopsy will reveal what type of germ is causing the infection • The antibiotics are usually administered through a vein for at least four to six weeks • Side effects may include nausea, vomiting and diarrhea • An additional course of oral antibiotics may also be needed for more-serious infections

28. Surgery • Depending on the severity of the infection, osteomyelitis surgery may include one or more of the following procedures • Drain the infected area • Remove diseased bone and tissue • Remove any foreign objects • Amputate the limb

29. Arthritis • Infectious Arthritis is inflammation of the joint space • Generally affects a single jointand result insuppurativeinflammation • Hematogenous seedingof joint is most common • Pain, swelling, limitation of movement common symptoms

30. Etiology, Epidemiology & Risk factors • Gonococcal infection most common cause in young adults caused by Neisseria gonorrheae • Nongonococcalarthritis occurs in older adults

31. Occasionally results from direct trauma, procedures (arthroscopy) or from contiguous soft tissue infection • S. aureusis most common cause • Other organisms : streptococci and aerobic Gram negative bacilli • Lyme disease in endemic areas • Risk factors: age, diabetes, immunosuppression, IV drug use, catheters, prior joint damage, sexually transmitted diseases

32. Diagnosis of Infectious Arthritis • History/examination to exclude systemic illness • Blood cultures • culture or DNA testing for N. gonorrheae • Urine may be used for DNA testing also • Culture of joint fluid, and skin lesions also indicated

33. Treatment & Management • Arthrocentesis with drainage of infected synovial fluid • Repeated therapeutic arthrocentesis often needed • Occassionally, arthroscopic or surgical drainage/debridement • Antimicrobial therapy should be directed at suspected and susceptibility results • Gonococcal arthritis: IV Ceftriaxone ( or Ciprofloxacin or Ofloxacin) then switch to oral Quinolone or Cefixime for 7-10 days

34. Nongonococcalinfectiuosarthritis • MSSA: Nafcillin or Cefazolin. • MRSA: Vancomycin • Streptococci: Penicillin or Ceftriaxone or Cefazolin • Enterobacetriacae: Ceftriaxone or Fluroquinolone • Pesudomonas: Piperacillin and Aminoglycoside • Animal bite : Ampicillin-Sulbactam • Lyme disease arthritis: Doxycycline for 1 month

35. Prognosis & Complications • Gonococcal arthritis has an excellent outcome • Nongonococcalarthritis • can result in scarring with limitation of movement, ambulation is affected in 50% of cases • Risk factors for long–term adverse sequellae include • Age, prior rheumatoid arthritis, poly-articular joint involvement, hip or shoulder involvement, virulent pathogens and delayed initiation or response to therapy

36. Acne vulgaris • Acne vulgaris (cystic acne or simply acne) • A common human skin disease • characterized by areas ofscaly red skin,blackheadsand whiteheads,and possibly scarring • Acne affects mostly skinwith the densest populationof sebaceous follicles • the face, the upper part of thechest, and the back

37. Signs and symptoms • Scars • Pigmentation

38. Cause • Hormonal • Genetic • Psychological • Infectious • Diet Different types of Acne Vulgaris: A: Cystic acne on the face, B: Subsiding tropical acne of trunk, C: Extensive acne on chest and shoulders.

39. Infectious Agent • Propionibacterium acnes (P. acnes) is the anaerobic bacterium species that is widely concluded to cause acne • Staphylococcus epidermidis has been universally discovered to play some role in acne formation

40. Medications • Benzoyl peroxide • Antiseptics • Antibiotics • Hormones • Topical retinoids • Oral retinoids • Anti-inflammatories Benzoyl peroxide cream