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 PRODUCTS1- SREPTOLYSINS OR HAEMOLYSIN

Streptolysin o antigenic , ASO , oxygen labile

Streptolysin s oxygen stable, non antigenic

2- Erythrogenic toxin (SPE )SUPERANTIGENBacteriophage – 3 types , A – B- C .SCARLET FEVER

B- EXTRACELLULAR PRODUCTS

DISEASESA - SAPURATIVE

A- SAPURATIVE 1- TONSILITIS / PHARINGITIS2- PERITONSILAR ABSCESS(QUINSY)3- OTITIS MEDIA4- ADENITIS5- IMPETIGO (PYODERMA)6- SCARLET FEVER7- CELLULITIS8- PUERPERAL SEPSIS9- INVASIVE SOFT TISSUE INFECTIOS

NECROTISING FASCITIS , MYOSITIS , TSS10 - 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) 10-40 % 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

TREATMENTPREVENTION

PENICILLIN OR AMPICILLIN + GENTAMICIN SCREEN- PREGNANT W. (35-37 W) CARRIER – PROPHYLAXIES

– IV- PENICILLIN – AT LABOUR

GROUP – D STREPT.NORMAL INTESTINAL FLORA

A- ENTEROCOCCIGROW IN 40% BILE-ACID,6.5% NACLPENICILLIN RESISTENTAMPICILLIN SENSITIVE- E. FAECALIS : 80% - 90% INFECTI.- E. FAECIUM : MANY AMPICILLIN R.

B- NON-ENTEROCOCCIPENICILLIN SENSETIVESTREPT . BOVIS

DISEASES

URINARY TRACT INFECTIONS ENDOCARDITIS WOUND INFECTIONS

TREATMENT

AMPICILLIN + GENTAMICIN

VANCOMYCIN ( VRE )

ALPHA – HEMOLYTIC STREPTOCOCCI

S.PNEUMONIAE

VIRIDANS

S.PNEUMONIAE

PNEUMONIABACTEREMIAMENINGITISSEPTIC

ARTHRITISPERITONITIS

OTITIS MEDIASINUSITISCONJUNCTIVITIS

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

DIAGNOSISSPUTUM , 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

ENDOCARDITISFEVER , 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