Bacterial infection


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Bacterial infection

  1. 1. A B AC T E R I A L I N F E C T I O N I S T H E I N VA S I O N O F B O DY T I S S U E S B Y D I S E A S E - C AU S I N G B AC T E R I A , T H E I R M U LT I P L I C AT I O N A N D T H E R E AC T I O N O F B O DY T I S S U E S TO T H E S E M I C RO O RG A N I S M S A N D T H E TOX I N S T H AT T H E Y P RO D U C E . Bacterial Infection
  2. 2. Topics  Leprosy  Tularemia  Botryomycosis  Actinomycosis  Syphilis  Gonorrhoea  Tuberculosis  Cat-Scratch Disease  Scarlet fever  Diphtheria  Meliodosis  Tetanus  Rhinoscleroma  Noma
  3. 3. Leprosy  Also called as Hansen’s Disease.  Caused by Mycobacterium leprea.  Affects skin, peripheral nerves, upper respiratory tract, eyes, testes, bones and joints.  It is unique in exhibiting dopa oxidase activity.  Staining smears taken from skin and nasal mucosa with ZN method demonstrate the presence of the bacilli.
  4. 4. Tuberculoid Type Lepramatous Type  Lesions are characterised by single or multiple macular, erythematous eruptions.  Peripheral nerves are involved with loss of sensation accompanied by loss of sweating of affected skin.  These develop early erythematous macules or papules that lead to progressive thickening of skin and characteristic nodules.  Facial nerve paralysis occurs due to facial nerve involvement. Types
  5. 5. Histopathology Well formed granulomatous inflammation demonstrating clusters of histiocytes and macrophages
  6. 6. Pathogenesis  Host’s defenses are crucial in determining patient’s response to disease.  Tuberculoid type of leprosy is characterized by strong CMI, positive lepromin test, granuloma formation, paucity of bacilli.  Lepromatous type of leprosy is characterized by suppressed CMI, negative lepromin test, no granuloma formation and multiple bacilli.
  7. 7. Diagnosis and Treatment  Tests for humoral responses are monoclonal antibodies, ELISA, PCR, etc.  In children sweat function test is used.  MDT is used which includes rifampicin, dapsone and clofazimine is used for treatment.  Tuberculoid type rifampicin + dapsone for 6 months.  Lepramatous type rifampicin + dapsone + clofazimine
  8. 8. Tularemia  Also called Rabbit Fever.  It is highly communicable and transmitted from infected mammals to humans.  It occurs more frequently in adults.
  9. 9. Clinical Features  Based on site of infection, tularemia has 6 clinical symptoms: a). Ulceroglandular(most common) b). Glandular c). Oropharyngal d). Pneumonic e). Oculoglandular f). typhoidal
  10. 10. Treatment  Disease responds to antibiotic therapy.  Streptomycin is the drug of choice.  Also responds well to adequate doses of gentamicin and tetracycline.
  11. 11. Botryomycosis  It is a chronic granulomatous infection.  A number of common bacteria such as staphylococcus, streptococcus, Escherichia, pseudomonas and probably many others may serve as etiologic agents of the disease.
  12. 12. Histopathology
  13. 13. Treatment  This condition may be caused by a variety of different micro organisms of low virulence.  Therefore, pathogenesis may be related more to a modified host resistance or tissue hypersensitivity than to a specific micro organisms.  Treatment is non specific, however surgical invention aids in cure.
  14. 14. Actinomycosis  It is a chronic, granulomatous, suppurative and fibrosing disease caused by anaerobic or microphilic gram positive, non acid fast, branched filamentous bacteria.  They are a normal flora of oral cavity, colon and vagina.  It is characterized by formation of abscesses that tend to drain by formation of sinus tracts.  They are classified according to the location of lesions as- -cervicofacial -abdominal -pulmonary forms It appears to be an endogenous infection and not communicable.
  15. 15. Histopathology Tongue lesions Tonsil lesions
  16. 16. Treatment and Prognosis  Long standing fibrosis cases are treated by draining the abcsess, excising the sinus tract with high doses of antibiotics.  Surgical drainage of abcsesses and excision of sinus tract is necessary to accelerate healing.
  17. 17. Syphilis  It is a veneral i.e. sexually transmitted disease caused by spirocheates, treponema pallidum.  It is transmitted by following routes: Coitus Transfusion of infected blood Mother to foetal transmission
  18. 18. Acquired syphilis Congenital syphilis  Mainly contracted as a veneral disease.  It may also be acquired by dentists while working on infected patients in a contagious state.  Its divided into 3 types based on their appearance and type of lesions: a).Primary b).Secondary c). Tertiary  It is only transmitted from infected mother to foetus only.  It is a very rare disease.  Morphological features are : a). Saddle nose b). Bony lesions, mucocutaneous lesions c). High palatal arch d). Mulberry molar Types
  19. 19. Demonstration of treponemas Serological test  Dark ground microscopy  Direct flourescent antibody staining for T.pallidum.  Treponemas in tissue by: a). Silver impregnation method b). Immunoflourescent staining  Non treponemal test  Treponemal test Diagnosis VDR L RPR TPI TPH A
  20. 20. Histopathology
  21. 21. Prophylaxis  Early syphilis: Benzathine benzyl penicillin 24 lac units i.m. in a single dose after sensitivity test.  Late syphilis: Benzathine benzyl penicillin 24 lacs units i.m. once weekly for 3 weeks.
  22. 22. Hutchinson's Triad  Hypoplasia of incisor and molar teeth.  8th nerve deafness and interstitial keratitis.  75% of congenital syphilis patients suffer from one or more components of Hutchinson's triads.
  23. 23. Gonorrhoea  It is a veneral disease affecting the male and female genitourinary tract.  It is caused by gram negative diplococci Neisseria gonorrhoea.  The bacterium is a strict parasite and dies rapidly outside the host in 1 to 2 hr in exudates and in 3 to 4 days in culture.
  24. 24. Oral Manifestations  Extra genital infection of the oral cavity occurs as a result of oral-genital contact or inoculation through infected hands.  Lips may develop acute painful ulceration, gingiva may become erythematous with or without necrosis.  Tongue may present red, dry ulcerations or become glazed or swollen with painful erosions.  Gonococcal pharyngitis and tonsilitis are also well recognized.
  25. 25. Diagnosis and Treatment  Diagnosis is established by bacteriological examination of smear or culture.  Organism is sensitive to large doses of penicillin or doxycycline.
  26. 26. Tuberculosis  It is an infectious, granulomatous disease caused by mycobacterium tuberculosis.  Primarily affects lungs but also affected are intestines, bones, joints, meninges, lymph glands, skin and other tissues.  The bacterium is a facultative intracellular parasite.  It causes pulmonary or generalized infection in immunocompromised patients.
  27. 27. Pathogenesis Bacilli-host interaction: droplet nuclei inhaled by patient Most bacilli are exhaled by ciliary reaction and 10% enters the alveoli Initial stage is asymptomatic but 2 – 4 weeks after infection, specific immunity develops and accumulation of a large number of activated macrophages at the site of primary lesion.(granulomatus or tubercles are formed). Lesion consists of epithelioid cells, langerhans cells, plasma cells and fibroblasts Central part of the lesion contains caseous necrosis (dry cheesy, granular and yellow in appearance). Ranne complex necrotic material may undergo calcification(in lung parenchyma or hilar lymph nodes. Sometimes necrotic material may liquefy, discharging in the lungs leading to cavity formation.
  28. 28. Histopathology Tuberculosis granulomas demonstrated by ZN stain
  29. 29. Oral Manifestations  Most commonly affected site is tongue. Others are palate, lips, buccal mucosa, gingiva and frenula.  Usual presentation is irregular superficial or deep painful ulcers which tend to increase in size slowly.  It may also involve the bone of the maxilla and mandible.  Microorganisms may enter the pulp chamber and root canal of the tooth with an open cavity.
  30. 30. Treatment  Isoniazid (NPH) combined with rifampicin for 9 months  INH and rifampicin and pyrazinamide for 2 months followed by INH and rifampicin for 4 months.  Other drugs used are streptomycin and ethambutol.
  31. 31. Cat-Scratch Disease  It is a condition caused by Bartonella lenselae a gram negative bacillus demonstrable with silver stain.  It occurs at any age most commonly in children and young adults by a traumatic break in the skin by scratch or by household bite of cat, dog or monkeys.
  32. 32. Histopathology Lymph node necrosis Swelling due to inflammation
  33. 33. Treatment and Prognosis  Prognosis is good since the disease is self limiting and regresses within a period of weeks or months.  Incision and drainage of involved node may be necessary.  Antibiotic therapy is ineffective
  34. 34. Scarlet Fever  It is a highly contagious, systemic infection.  It occurs predominantly in children.  It is caused by β-heamolytic streptococci, streptococcus pyogens which produces a pyrogenic exotoxin  These organisms produce clear heamolysis around colonies on blood agar plates.  Scarlet fever may reflect a hypersensitivity reaction requiring prior exposure to the toxin.
  35. 35. Histopathology Necrotic conective tissue
  36. 36. Oral Manifestation  Chief manifestations are termed as ‘Stomatitis scarlatina’.  Small, red macules may appear in the hard and soft palate and uvula which are called Forchheimer spots.  Palate and throat is often fiery red.  Tonsils and faucial pillars are usually swollen and sometimes covered with a grayish exudate.  In early course of the disease, tongue exhibits a white coating and the fungiform pappila are edematous and hyperemic. This phenomenon has been described clinically as ‘strawberry tongue’.  Later, the tongue coating is lost and appears red and glistening and smooth except the pappliae this is called as ‘raspberry tongue’.
  37. 37. Diptheria  It is an acute, life threatening infection and communicable disease of skin and mucous membrane.  Caused by toxemic strains of corneybacterium diptheria.  Characterized by local inflammation and formation of a graying adherent psuedomembrane which bleeds on removal.  Also referred as ‘The strangling angel of children’.
  38. 38. Clinical Features  Signs and symptoms arise 1 to 5 days after exposure.  Swelling of neck (Bull neck).  Onset is gradual.  Manifestations are fever, sore throat, weakness, headache, change of voice.
  39. 39. Of patients Of tonsils  Diptheria cases: Pseudomembrane present  Diptheria carriers: Pseudomembrane absent  On the basis of location of pseudomembrane: a). Pharyngeal b). Laryngeal c). Tracheal d). Tonsillar e). Nasal f). Conjunctival g). Cutaneous h). Genital Classification
  40. 40. Oral Manifestations  Formation of ‘Diptheric Membrane’.  In oral cavity, appears as non specific ulcers.  Soft palate is temporarily paralysed.  Patients have peculiar nasal twang.  If infection spreads unchanged in repiratory tract: a). Larynx becomes edematous, covered by pseudomembrane. b). Husky voice c). Suffocation if airways is not cleared.
  41. 41. Meliodosis  Specific infection in man and animals.  Caused by burkholderia pseudomallei.  It is endemic in certain areas of far east including Burma, India, Indo-china, malaysia and thialand.
  42. 42. Diagnosis and Treatment  Diagnosed by culturing the organism from clinical and throat sample.  Treatment involves:  Incision and drainage accompanied by massive antibiotic therapy.  Tetracycline alone or in combination with chloremphenicol is drug of choice.
  43. 43. Acute Chronic  Fever  Diarrhoea  Acute pulmonary infection  Death as a result of septicemia  In those patients who have survived acute type.  It is of granulomatous type, characterized by multiple, small, non specific abscesses. Clinical Features
  44. 44. Tetanus  Tetanus is an acute infection of the nervous system characterized by intense activity of motor neurons and resulting in severe muscle spasms.  It is caused by exotoxin of the anaerobic gram positive bacillus clostridium tetani.  Most commonly occurs in non immunized, partially immunized or even fully immunized people.  In infants were umbilical cord is cut with unsterile instrument or in children with otorrhea.  After acute trauma.
  45. 45. Pathogenesis  Suitable anaerobic conditions favour the spores of clostridium to enter the wounds and germinate.  These produce tetanospasmin(potent neurotoxin)  It binds to the peripheral motor nerve terminals and enters the axons cell body in the brain stem and spinal cord in a retrograde direction.  Toxins migrate to the synapse where they block the receptors of glycine and GABA which increases the resting state of locomotor neurons thereby producin rigidity.
  46. 46. Generalized Tetanus Local Tetanus  Lock jaw due to the spasm of masseter is the first symptom.  Dysphagia, stiffness or pain in the neck, shoulder or back muscles occurs concurrently.  Laryngeal spasm leading to asphyxia.  Spasm of muscle near the wound is uncommon.  Cephalic tetanus characterized by spasm of muscle and facial palsy is rare.  Acute oral infection, trauma, TMJ dysfunction and even hysteria may be manifested. Types
  47. 47. Prophylaxis  Wound debriment and booster doses of tetanus toxoid.  For unimmunized indivisuals, anti-tetanus serum(ATS) 1500 units or TIG 250 units should be given.
  48. 48. Rhinoscleroma  It is a chronic, slowly progressive, localized infectious, granulomatous disease caused by bacillus klebsiella rhinoscleromatus which is a gram negative, non motile bacillus.  Mode of infection is through nasal exudates.  Granulomatous lesions are chiefly found in upper respiratory tract involving nose, lacrymal glands, orbit, skin and paranasal sinuses.  Oral lesions impair taste, anesthesia of the soft palate and enlargement of the uvula and upper lip are described.
  49. 49. Treatment  Administration of tetracycline or ciprofloxacin.  If left untreated, outcome is fatal.
  50. 50. Noma  It means a rapidly spreading mutilating, gangrenous stomatitis that occurs usually in debilitated or nutritionally deficient persons.  Occurs chiefly in undernourished persons.  The condition is usually seen around the gingiva and progressed to destruction of the mouth and the lower lip.
  51. 51. Clinical Features
  52. 52. Treatment  The prognosis is considerably better if antibiotics are administered before the patient reaches the final stage.  Immediate treatment of any existing malnourishment further improves the probability of saving the patient.