STREPTOCOCCI

General character Gram positive cocci arranged in chains Catalase test negative Fastidious Facultative anaerobes Penicillin sensitive (Streptococcus faecalis ) Resistant to AG (GENTAMICIN )

GROUP A STREPT STREPTOCOCCUS PYOGENES

Most important pathogen Distinguished by bacitracin test (sensitive) Some are capsulated (hyaluronic acid)

epidemiology Acquired through infected respiratory droplet Direct contact _ Skin, hand Indirect contact _contaminated objects Spread enhanced by poverty overcrowding poor ventilation

Source of infection A - Patient with active disease – tonsillitis Convalescent carriers – throat B - Asymptomatic carriers (20% -school children ) – throat Prevalent in children – 3 – 8 yrs

VIRULENCE FACTORES A- CELL ASSOCIATED 1- M protein (antiphagocytic) - originates from cytoplasmic membrane produces protective type specific abs 2- lipoteichoic acid adhesion factor for attachment 3- hyaluronic acid capsule - antiphagocytic

3- STREPTOKINASE (fibrinolysin)  Thrombotic disease – coronary thrombosis 4- DNAases A, B, C, D.  AntiDNAase B - DIAGNOSE SKIN infections 5- HYALURONIDASE – spread factor 6- LIPOPROTEINASE – opacity factor

B- EXTRACELLULAR PRODUCTS 1- SREPTOLYSINS OR HAEMOLYSIN  Streptolysin o antigenic, ASO, oxygen labile  Streptolysin s oxygen stable, non antigenic 2- Erythrogenic toxin (SPE )  SUPERANTIGEN  Bacteriophage – 3 types, A – B- C.  SCARLET FEVER B- EXTRACELLULAR PRODUCTS

DISEASES A - SAPURATIVE A- SAPURATIVE 1- TONSILITIS / PHARINGITIS 2- PERITONSILAR ABSCESS(QUINSY) 3- OTITIS MEDIA 4- ADENITIS 5- IMPETIGO (PYODERMA) 6- SCARLET FEVER 7- CELLULITIS 8- PUERPERAL SEPSIS 9- INVASIVE SOFT TISSUE INFECTIOS NECROTISING FASCITIS, MYOSITIS, TSS 10 - BACTERIMIA

B- NON- SUPPURATIVE (DELAYED SEQUELAE) 1- RHEUMATIC FEVER : autoimmune disease follows throat infection only recur (M – SEROTYPES) 2- ACUTE GLOMERULONEPHRITIS Ag – Ab complexes May follow both throat or skin infection NO recurrence B-NON SUPPURATIVE (DELAED SEQUELAE)

LABORATORY DIAGNOSIS SPECIMEN THROAT SWAB PUS WOUND BLOOD ASPIRATES SERUM – SEROLOGY : ASO TITRE

MICROSCOPY GRAM – STAIN – GRAM-POSITIVE COCCI IN CHAIN – USELESS IN THROAT SWAB

CULTURE - IDENTIFICATION BLOOD-AGAR (AEROBIC- ANAEROBIC) BETA- HAEMOLYSIS (COMPLETE ) ID – BACITRACIN SENSITIVITY – LANCEFIELDS GROUPING (CELL WALL CHO- Ag) – STREPTEX

SEROLOGY ASO-TITRE – RHEUMATIC FEVER – ACUTE GLOMERULONEPHRITIS Anti-DNAase B – RECENT GROUP -A INFECTIONS (SKIN)

TREATMENT PENICILLIN – 10 DAYS ALLERGY- – ERYTHROMYCIN – CEPHALOSPORINS CEPHRADIN CEFUROXIME

GROUP C AND G STREPT. SORE THROAT SKIN INFECTION WOUND INFECTION SOFT – TISSUE GENITAL – INFECTION CELLULITIS SEPTICAEMIA

GROUP-B STREPTOCOCCUS (SREPT. AGALACTIAE) RESERVOIR- COLON (RECTUM) % FEMALE. CARRIER (VAGINA) 70% - NEOBORN – COLONISED DURING BIRTH < 1% GET INVIASIVE INFECTION

DISEASES A – EARLY ONSET (24 – 48 h ) RISK – FACTORS RUPTURED MEMBRANES (>18h PREMATURITY PROM (< 37 WEEKS) MULTIPLE BIRTH (TWINS) LOW BIRTH WEIGHT

CLINICAL PICTURE RESPIRATORY DISTRESS SYNDROME SEPTICAEMIA MENINGITIS MORTALITY :

B- LATE – ONSET HOSPITAL- AQUIRED (NOSOCOMIAL) MENNGITIS IN FULL – TERM NEONAT. BETTER PROGNOSIS MORTALITY

DIAGNOSIS CLINICAL LATEX – AGGLUTINATION CULTURE ID – CAMP – TEST – STREPTEX (GROUPING)

INFECTIONS IN ADULTS POST-PARTUM SEPSIS CHORIOAMNIONITIS IMMUNOCOMPROMISED – SEPSIS – CELLULITIS – ARTHRITIS – PNEUMONIA

TREATMENT PREVENTION PENICILLIN OR AMPICILLIN + GENTAMICIN SCREEN- PREGNANT W. (35-37 W) CARRIER – PROPHYLAXIES – IV- PENICILLIN – AT LABOUR

GROUP – D STREPT. NORMAL INTESTINAL FLORA A- ENTEROCOCCI GROW IN 40% BILE-ACID,6.5% NACL PENICILLIN RESISTENT AMPICILLIN SENSITIVE - E. FAECALIS : 80% - 90% INFECTI. - E. FAECIUM : MANY AMPICILLIN R. B- NON-ENTEROCOCCI PENICILLIN SENSETIVE STREPT. BOVIS

DISEASES URINARY TRACT INFECTIONS ENDOCARDITIS WOUND INFECTIONS TREATMENT AMPICILLIN + GENTAMICIN VANCOMYCIN ( VRE )

ALPHA – HEMOLYTIC STREPTOCOCCI S.PNEUMONIAE VIRIDANS

S.PNEUMONIAE PNEUMONIA BACTEREMIA MENINGITIS SEPTIC ARTHRITIS PERITONITIS OTITIS MEDIA SINUSITIS CONJUNCTIVITIS BRONCITIS

GRAM POSITIVE DIPLOCOCCI POLYSACCHARIDE CAPSULES (85) ANTIPHAGOSITIC OPSONIZING ANTIBODIES ANTCAPSULAR AB. ARE PROTECTIVE PNEUMOLYSIN

RISK FACTORS CEREBRAL IMPAIRMENT VIRAL INFECTION OLD AGE HEART FAILURE SPLENECTOMY SCA, MULTIPLE MYLOMA, HIV SKULL FRACTURE

DIAGNOSIS SPUTUM, BLOOD, CSF MICROSCOPY QUELLUNG REACTION BILE SOLUBLE OPTOCHIN SENSETIVE BLOOD CULTURE + IN 15% LATEX AGGLUTINATION SENSETIVITY TEST

TREATMENT, PREVENTION CEFTRIXONE + VANCOMYCIN PENICILLIN ERYTHROMYCIN CLINDAMYCIN VACCIN

VIRIDANS NORMAL FLORA – OROPHARYNX – SKIN – GIT

ENDOCARDITIS FEVER, ANEMIA, HEART MURMUR S. MUTANS –POLYSACCHARIDES (DEXTRAN) – DENTAL CARIES S.SANGUIS S.SALIVARIUS S.MITIS S. BOVIS ( CA. COLON ) S.INTERMEDIUS ( MILLERI) – DENTAL, BRAIN, ABDOMINAL ABSCESSES