1. .

2. Staphylococci are gram positive cocci, Staphylococci are gram positive cocci, Occur in grape like clusters, Occur in grape like clusters, In Greek; staphyle - Bunch of grapes In Greek; staphyle - Bunch of grapes Kokkus - Berry Kokkus - Berry

3. CLASSIFICATION: A) Based on coagulase production: 1. Coagulase positive: Eg- S. aureus 1. Coagulase positive: Eg- S. aureus 2. Coagulase negative: Eg- S. epidermidis 2. Coagulase negative: Eg- S. epidermidis S. saprophyticus S. saprophyticus B) Based on pathogenicity: 1. Common pathogen: Eg- S. aureus 1. Common pathogen: Eg- S. aureus 2. Opportunistic pathogens: Eg- S. epidermidis 2. Opportunistic pathogens: Eg- S. epidermidis S. saprophyticus S. saprophyticus 3. Non pathogen: Eg- S. homonis 3. Non pathogen: Eg- S. homonis

4. STAPHYLOCOCCUS AUREUS MORPHOLOGY: These are spherical cocci. These are spherical cocci. Approximately 1μm in diameter. Approximately 1μm in diameter. Arranged characteristically in grape like clusters. Arranged characteristically in grape like clusters. They are non motile and non sporing. They are non motile and non sporing. A few strains possess capsules. A few strains possess capsules.

5. CULTURE: Media used :- i) Non selective media: Nutrient agar, i) Non selective media: Nutrient agar, Blood agar, Blood agar, MacConkey’s agar. MacConkey’s agar. ii) Selective media: Salt-milk agar, ii) Selective media: Salt-milk agar, Ludlam’s medium Ludlam’s medium

6. Cultural Characteristics: i) On nutrient agar- The colonies are large, circular, convex, smooth, shiny, opaque and easily convex, smooth, shiny, opaque and easily emulsifiable. Most strains produce golden yellow emulsifiable. Most strains produce golden yellow pigments. pigments.

7. ii) On MacConkey’s agar- The colonies are small & pink in colour. iii) On blood agar- Most strains produce β- haemolytic colonies.

8. Biochemical reactions: 1) Catalase test- Positive.

9. 2) Coagulase test- i) Slide coagulase test- Positive. i) Slide coagulase test- Positive. ii) Tube coagulase test- Positive. ii) Tube coagulase test- Positive. SLIDE COAGULASE TESTTUBE COAGULASE TEST

10. PATHOGENICITY: PATHOGENICITY: Source of infection: A) Exogenous: patients or carriers A) Exogenous: patients or carriers B) Endogenous: From colonized site B) Endogenous: From colonized site Mode of transmission: A) Contact: direct or indirect( through fomites) A) Contact: direct or indirect( through fomites) B) Inhalation of air borne droplets B) Inhalation of air borne droplets

11. Disease: Diseases produced by Staphylococcus aureus is studied under 2 groups: A) Infections A) Infections B) Intoxications B) Intoxications

12. A) INFECTIONS: Mechanism of pathogenesis: Cocci gain access to damaged skin, mucosal or Cocci gain access to damaged skin, mucosal or tissue site tissue site Colonize by adhering to cells or extracellular matrix Colonize by adhering to cells or extracellular matrix Evade the host defense mechanisms and multiply Evade the host defense mechanisms and multiply Cause tissue damage Cause tissue damage

13. Common Staphylococcal infections are: 1) Skin and soft tissue: Folliculitis, furuncle (boil), carbuncle, styes, abscess, wound infections, impetigo, paronychia and less often cellulitis. Folliculitis

14. Furuncle (boil) Carbuncle

15. StyesAbscess

16. Impetigo Paronychia CellulitisWound infection

17. 2) Musculoskeletal: Osteomyelitis, arthritis, bursitis, pyomyositis. osteomyelitis osteomyelitis 3) Respiratory: Tonsillitis, pharyngitis, sinusitis, otitis, bronchopneumonia, lung abscess, empyema, rarely pneumonia.

18. 4) Central nervous system: Abscess, meningitis, intracranial thrombophlebitis. 5) Endovascular: Bacteremia, septicemia, pyemia, endocarditis. Endocarditis Endocarditis 6) Urinary: Urinary tract infection.

19. B) INTOXICATIOINS: The disease is caused by the bacterial exotoxins, which are produced either in the infected host or preformed in vitro. There are 3 types- 1. Food poisoning 2. Toxic shock syndrome 3. Staphylococcal scalded skin syndrome

20. 1) Food poisoning: Enterotoxin is responsible for manifestations of staphylococcal food poisoning. Enterotoxin is responsible for manifestations of staphylococcal food poisoning. Eight types of enterotoxin are currently known, named A, B, C1-3, D, E, and H. Eight types of enterotoxin are currently known, named A, B, C1-3, D, E, and H. It usually occurs when preformed toxin is ingested with contaminated food. It usually occurs when preformed toxin is ingested with contaminated food. The toxin acts directly on the autonomic nervous system to cause the illness, rather than gut mucosa. The toxin acts directly on the autonomic nervous system to cause the illness, rather than gut mucosa.

21. The common food items responsible are - milk and milk products, meat, fish and ice cream. The common food items responsible are - milk and milk products, meat, fish and ice cream. Source of infection- food handler who is a carrier. Source of infection- food handler who is a carrier. Incubation period- 2 to 6 hours. Incubation period- 2 to 6 hours. Clinical symptoms- nausea, vomiting and diarrhoea. Clinical symptoms- nausea, vomiting and diarrhoea. The illness is usually self limited, with recovery in a day or so. The illness is usually self limited, with recovery in a day or so.

22. 2) Staphylococcal Toxic shock syndrome (STSS): STSS is associated with infection of mucosal or sequestered sites by TSST( formerly known as enterotoxin type F) producing S.aureus. STSS is associated with infection of mucosal or sequestered sites by TSST( formerly known as enterotoxin type F) producing S.aureus. It is fatal multisystem disease presenting with fever, hypotension, myalgia, vomiting, diarrhoea, mucosal hyperemia and erythematous rash which desquamates subsequently. It is fatal multisystem disease presenting with fever, hypotension, myalgia, vomiting, diarrhoea, mucosal hyperemia and erythematous rash which desquamates subsequently.

24. 2 types of STSS known: i) Menstrual associated STSS: Here colonization of S.aureus occurs in the vagina of menstruating woman who uses highly absorbent vaginal tampons. ii) Non menstrual associated STSS: Here colonization of S.aureus occurs in other sites like surgical wound.

25. 3) Staphylococcal scalded skin syndrome (SSSS): Exfoliative toxin produced by S.aureus is responsible for this. Exfoliative toxin produced by S.aureus is responsible for this. It is a skin disease in which outer layer of epidermis gets separated from the underlying tissues. It is a skin disease in which outer layer of epidermis gets separated from the underlying tissues.

26. Types of SSSS: Severe form Milder form Severe form Milder form In new born - Ritter’s disease - Pemphigus neonatorum neonatorum In older patients - Toxic epidermal - Bullous necrolysis impetigo necrolysis impetigo

27. Toxic epidermal necrolysis Ritter’s disease Bullous impetigo Pemphigus neonatorum

28. LAB DIAGNOSIS: Specimens collected: Depends on the type of infection. Suppurative lesion- Pus, Suppurative lesion- Pus, Respiratory infection- Sputum, Respiratory infection- Sputum, Bacteremia & septicemia- Blood, Bacteremia & septicemia- Blood, Food poisoning- Feces, vomit & the remains of suspected food, Food poisoning- Feces, vomit & the remains of suspected food, For the detection of carriers- Nasal swab. For the detection of carriers- Nasal swab.

29. I) Direct microscopy: Direct microscopy with Gram stained smear is useful in case of pus, where cocci in clusters are seen. Direct microscopy with Gram stained smear is useful in case of pus, where cocci in clusters are seen. This is of no value for specimen like sputum where mixed flora are normally present. This is of no value for specimen like sputum where mixed flora are normally present. Methods of examination:

30. c) Gram staining: Smears are examined from the culture plate and reveals Gram positive cocci(1μm in diameter) arranged in grape like clusters. II) Culture: a) Media used: b) Cultural Characteristics:

31. d) Biochemical reactions: III) Antibiotic sensitivity tests done as a guide to treatment. IV) Bacteriophage typing is done for epidemiological purposes. V) Serological tests are not useful.

32. TREATMENT: Drug resistance is common. Drug resistance is common. Benzyl penicillin is the most effective antibiotic, if the strain is sensitive. Benzyl penicillin is the most effective antibiotic, if the strain is sensitive. Cloxacillin or Methicillin is used against Cloxacillin or Methicillin is used against beta-lactamase producing strains. beta-lactamase producing strains. Methicillin Resistant Staphylococcus aureus (MRSA) strains have become common. Methicillin Resistant Staphylococcus aureus (MRSA) strains have become common. Vancomycin is used in treatment of infections with MRSA strains. Vancomycin is used in treatment of infections with MRSA strains.

33. EPIDEMIOLOGY: Staphylococci are primary parasites of human beings and animals. Staphylococci are primary parasites of human beings and animals. Hospital infections caused by staphylococci deserve special attention because of their frequency & they are caused by strains resistant to various antibiotics. Hospital infections caused by staphylococci deserve special attention because of their frequency & they are caused by strains resistant to various antibiotics. Staphylococci are the common cause of postoperative wound infection and other hospital cross infections. Staphylococci are the common cause of postoperative wound infection and other hospital cross infections.

34. PREVENTION: Isolation & treatment of MRSA patients. Isolation & treatment of MRSA patients. Detection of carriers among hospital staff, their isolation & treatment. Detection of carriers among hospital staff, their isolation & treatment. Avoid indiscriminate usage of antibiotics. Avoid indiscriminate usage of antibiotics.

35. Coagulase Negative Staphylococci( CoNS ): Two species of coagulase negative Staphylococci can cause human infections- 1. Staphylococcus epidermidis 2. Staphylococcus saprophyticus

36. S. Epidermidis : It is a common cause of stitch abscesses. It is a common cause of stitch abscesses. It has predilection for growth on implanted foreign bodies such as artificial valves, shunts, intravascular catheters and prosthetic appliances leading to bacteraemia. It has predilection for growth on implanted foreign bodies such as artificial valves, shunts, intravascular catheters and prosthetic appliances leading to bacteraemia. In persons with structural abnormalities of urinary tract, it can cause cystitis. In persons with structural abnormalities of urinary tract, it can cause cystitis. Endocarditis may be caused, particularly in drug addicts. Endocarditis may be caused, particularly in drug addicts.

38. Streptococcal Diseases Streptococcus pyogenes

39. Streptococcus pyogenes Pyogenes means pus producing One of the most important pathogens One of the most important pathogens Gram positive cocci in chains Gram positive cocci in chains Lancefield Serological Group A Lancefield Serological Group A Beta Hemolytic on blood agar Beta Hemolytic on blood agar

40. Gram Stain of S. pyogenes

41. Hemolysis on Blood Agar Plates Alpha hemolysis-organism excretes hemolysins which partially break down rbc (incomplete hemolysis) thus a greenish zone appears around colony. S. pneumoniae Alpha hemolysis-organism excretes hemolysins which partially break down rbc (incomplete hemolysis) thus a greenish zone appears around colony. S. pneumoniae Beta hemolysis-organisms excretes potent hemoysins which completely lyse rbc (complete hemolysis) thus a clear zone appears around colony. S. pyogenes Beta hemolysis-organisms excretes potent hemoysins which completely lyse rbc (complete hemolysis) thus a clear zone appears around colony. S. pyogenes

42. S.pyogenes S. pneumonia Beta hemolysis Alpha hemolysis

43. Diseases caused by S. pyogenes Strep throat Strep throat Impetigo Impetigo Erysipelas Erysipelas Cellulitis Cellulitis Invasive Strep A infections Invasive Strep A infections Necrotizing fasciitis Necrotizing fasciitis Myositis Myositis Toxic shock-like syndrome Toxic shock-like syndrome

45. Erysipelas Acute infection and imflammation of the dermal layer of skin. Acute infection and imflammation of the dermal layer of skin. Painful red patches which enlarge and thicken Painful red patches which enlarge and thicken Treatment -penicillin or erythromycin Treatment -penicillin or erythromycin

46. Erysipelas

47. Strep Throat Most common of all Strep diseases Most common of all Strep diseases Spread by saliva or nasal secretions Spread by saliva or nasal secretions Incubation period 2-4 days Incubation period 2-4 days Sore throat, slight fever (101) Sore throat, slight fever (101) Important to treat immediately to avoid post strep diseases Important to treat immediately to avoid post strep diseases

48. Diagnosis and treatment of Strep Throat Tell tale symptoms are slight fever associated with sore throat and visual of pus in back of throat Tell tale symptoms are slight fever associated with sore throat and visual of pus in back of throat Quick diagnostic tests (Molecular) available but must be confirmed by throat swab and growth on blood agar (beta hemolysis) Quick diagnostic tests (Molecular) available but must be confirmed by throat swab and growth on blood agar (beta hemolysis)

49. Diagnosis and treatment of Strep Throat If the strain of S. pyogenes is lysogenic for a particular phage which expresses an erythrogenic toxin the result is Scarlet fever If the strain of S. pyogenes is lysogenic for a particular phage which expresses an erythrogenic toxin the result is Scarlet fever Rash appears and characteristic is the strawberry colored tongue Rash appears and characteristic is the strawberry colored tongue

50. Strawberry Tongue

51. Treatment of Strep Penicillin G or Erythromycin are drugs of choice Penicillin G or Erythromycin are drugs of choice Although the disease is self-limiting it is important to treat immediately to avoid post strep complications Although the disease is self-limiting it is important to treat immediately to avoid post strep complications

52. Poststreptococcal diseases Rheumatic Fever-autoimmune disease involving heart valves,joints, nervous system. Follows a strep throat Rheumatic Fever-autoimmune disease involving heart valves,joints, nervous system. Follows a strep throat Acute glomerulonehritis or Bright’s Disease- inflamatory disease of renal glomeruli and structures involved in blood filter of kidney. Due to deposition of Ag/Ab complexes Acute glomerulonehritis or Bright’s Disease- inflamatory disease of renal glomeruli and structures involved in blood filter of kidney. Due to deposition of Ag/Ab complexes

53. Rheumatic Fever Most common cause of permanent heart valve damage in children Most common cause of permanent heart valve damage in children Exact cause not yet known but there appears to be some antibody cross reactivity between the cell wall of S. pyogenes and heart muscle Exact cause not yet known but there appears to be some antibody cross reactivity between the cell wall of S. pyogenes and heart muscle

54. Rheumatic Fever Diagnosis is based on symptoms and is difficult Diagnosis is based on symptoms and is difficult Occurs most frequently between ages of 6 and 15 Occurs most frequently between ages of 6 and 15 US it is about 0.05% of pop having strep infections US it is about 0.05% of pop having strep infections 100x more frequent in tropical countries 100x more frequent in tropical countries

55. Rheumatic Fever Treatment is via salicylates (aspirin derivatives) and corticosteroids to decrease inflammation and fever. Treatment is via salicylates (aspirin derivatives) and corticosteroids to decrease inflammation and fever.

56. Glomerular Nephritis Diagnosis based on history of Strep throat and clinical findings. Diagnosis based on history of Strep throat and clinical findings. Symptoms include fever, malaise,edema, hypertension and blood or protein in urine Symptoms include fever, malaise,edema, hypertension and blood or protein in urine Occurs in 0.5% of those having strep throat. Occurs in 0.5% of those having strep throat.

57. Glomerular Nephritis Treatment and Recovery Penicillin or erythromycin to eradicate and residual strep infection Penicillin or erythromycin to eradicate and residual strep infection 80-90% of cases recover with bed rest lasting for months 80-90% of cases recover with bed rest lasting for months Kidney damage in the remainder is often permanent resulting in chronic glomerular nephritis Kidney damage in the remainder is often permanent resulting in chronic glomerular nephritis

58. Streptococcus Pneumonia Caused by infection with Streptococcus pneumoniae (Pneumococci) Caused by infection with Streptococcus pneumoniae (Pneumococci) Gram positive, alpha hemolytic, not of lancefield serotype A Gram positive, alpha hemolytic, not of lancefield serotype A Often part of normal flora of respiratory track and becomes infective once hosts resistance is lowered. Classified as an endogenous infection. Often part of normal flora of respiratory track and becomes infective once hosts resistance is lowered. Classified as an endogenous infection.

59. Strep Pneumonia

60. S. pneumoniae Alpha hemolysis

61. Strep pneumonia Predisposing factors: upper respiratory viral infection, diabetes, alcoholism Predisposing factors: upper respiratory viral infection, diabetes, alcoholism 60-80% of all pneumonias 60-80% of all pneumonias

62. Strep Pneumonia

63. Cause of strep pneumonia Primary virulence factor is the capsular polysaccharide which protects the organism against phagocytosis Primary virulence factor is the capsular polysaccharide which protects the organism against phagocytosis Pathogenesis is due to rapid growth of bacteria in alveolar spaces Pathogenesis is due to rapid growth of bacteria in alveolar spaces

64. Symptoms of Strep Pneumonia Onset abrupt Onset abrupt Chest pains Chest pains Chills Chills Labored breathing Labored breathing

65. Diagnosis of Strep pneumonia Chest Xray Chest Xray Culture and staining Culture and staining Biochemical tests of isolated organism Biochemical tests of isolated organism

66. Treatment of Strep Pneumonia Typically treated with Penicillin G cefotaxime, oflaxacin or for those allergic to penicillins can be treated with erythromycin or tetracycline Typically treated with Penicillin G cefotaxime, oflaxacin or for those allergic to penicillins can be treated with erythromycin or tetracycline Pneumococcal vaccine (Pneumovax 23 or Pnu- immune 23) is available for the elderly Pneumococcal vaccine (Pneumovax 23 or Pnu- immune 23) is available for the elderly

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