Streptococci, Enterococci

Question 1

Diagnosis of S.Pyogens Group A

Answer 1

Gram (+) cocci, catalase (-), β-haemolytic

–> on blood agar

Question 2

Transmission of S.Pyogens Group A

Answer 2

Droplets, colonizes throat

Question 3

Pathogenesis/Vf of S.Pyogens Group A

Answer 3

M-proteins –> associated with RF
Pyrogenic exotoxins –> causes Scarlet fever

Question 4

Clinical Manifestations of S.pyogens Group A

Answer 4

1) Pharyngitis, Scarlet Fever: strawberry tongue, rash (exp.face), pharyngitis

2) Suppurative:
- impetigo,
- eryspiles,
- cellulitis,
- necrotizing fasciitis (streptococcal gangrene)
- streptococcal TSS (Toxic shock syndrome not associated with tampons )

3) Non-Suprative:
- RF (pancarditis, skin nodules, erythema marginatum, migratory arthritis, Sydenham’s chorea, increases inflm. markers (ESR,CRP), Rheumatic heart disease)

• Post-streptococcal glomerulonephritis (10d after GAS pharyngitis or 3wks after pyoderma)

Question 5

Test for Post-streptococcal glomerulonephritis

Answer 5

Urine dipstick–> dark-brown urine containing protein & RBC

Question 6

Treatment for S.pyogens Group A

Answer 6

Penicillin to eradicate nephrogenic GAS strains

Question 7

Diagnosis of S. agalactiae Group B

Answer 7

Gram (+) cocci, catalse (-), β-hemolytic

Question 8

Infection route of of S.agalactiae Group B

Answer 8

–> colonizes the lower GI tract & genitourinary tract
–> neonates: GBS colonized mother

Question 9

clinical Manifestations of S.agalactiae Group B

Answer 9

Neonates:
1) Bacteraemia
2) Pneumonia
3) Meningitis & sepsis

Question 10

Treatment for S.agalactiae Group A

Answer 10

–> test pregnant women (RCR for Rectal &vaginal swabs) at 35 wks
–> give mother penicillin as prophylaxis

Question 11

Diagnosis of Viridians Streptococci

Answer 11

gram (+) cocci, catalse (-), α-heamolytic & non-heamolytic

–> Optochin resistant
–> Bile resistant

Question 12

Infection route of S.Viridians

Answer 12

colonizes the oropharynx, GI & genitourinary tract

Question 13

clinical Manifestaions of S.Viridians

Answer 13

1) endocarditis after dental manipulation
2) Bacteremia in hematology patients receiving chemo (oral mucositis)
3) If S.bovis (S.gallolyticus) BSI= search for colon cancer
4) Aspiration pneumonia, abscesses formation

Question 14

pathogenesis/Vf of S.pneumonia

Answer 14

Virulent strains have polysaccharide capsule
–> IgA proteases
–> pneumolysin (its VF can damage human antibodies)

Question 15

clinical Manifestaions of S.pneumonia

Answer 15

1) >39 °C fever
2) cough
3) bloody and purulent sputum
4)dyspnoea
5) chest pain
6) Bacteremia
7) sinusitis
8) otitis media
9) meningitis

*MOPS: Meningitis, Otitis media, Pneumonia, and Sinusitis are the no.1 cause of S.pneumonia

Question 16

Treatment of S.pneumonia

Answer 16

Adult vaccine PPSV-23 (IgM)
Infant Vaccine PCV-13 (IgG)

Question 17

Diagnosise of Enterococci

Answer 17

gram (+), catalase (-), coagulase (+), γ- or α-heamolytic, aerobic & anaerobic

–> Bile resistant

Question 18

Infection route of Enterococci

Answer 18

colonizes Human intestine

Question 19

Pathogenesis/VF of Enterococci

Answer 19

Biofilm, Abx resistance (Carbapenem resistant)

Question 20

Clinical manifestation of Enterococci

Answer 20

1) Bacteremia with and without endocarditis
2) CA-BSI
3)HA-BASI
4) HA-UTI
5)diabetic foot ulcer
6)decubitus ulcer w/ faecal material

Question 21

Resistant phenotype of Enterococci and Treatment

Answer 21

Vacomycin resisatnt enterococci (VRE)

treatment (drugs): tigecycline, linezolid

Question 22

Diagnosis of Streptoc0ccus pneumonia

Answer 22

Gram (+) diplococcus, catalase (-)
- α-haemolytic
- Optochin sensitive
- Soluble in bile salts

Question 23

Risk factors of S.pneumonia

Answer 23

1) Extremes of age
2) smoking / chronic lung disease
3) splenectomy
4) HIV
5) Haematological B-cell and other malignancies
6) immunosuppressive medications &solid tumours
7) diabetes, chronic liver, kidney, lung & heart disease & alcoholism
8) low complement & hypoglobulinemia