Gram Positive Cocci 2Streptococcus

Lecture 8Summer, 2004

Demosthenes Pappagianis, MDMMI 480B

Streptococcus

Patterns of Fermentation

Group A Strep with Bacitracin disc

*no growth* area

Strep. pyogenes

Cytoplasmic Membrane

PeptidoglycanGroup CarbohydrateM Protein (& T, R)Cell Wall

Hyaluronic AcidCapsule

Lipoteicnoic AcidFimbriae

Group A Streptococcus ( hemolytic)

Strep. Follicular Exudate - tonsil

Streptococcal “Raspberry Tongue”

Streptoccal Enanthem

Scarlet Fever

Impetigo

Streptococcal Erysipelas

Streptococcal Cellulitis

Necrotizing Streptococcal Cellulitis

Varicella gangrenosa/Group A Strep. fasciitis

64 y/o male presented to the emergency room with fever, chills, nausea, malaise, and pain of the left leg of 4 days’ duration.

PE: Obese, “toxic appearing”, left leg tensely swollen, markedly erythematous, and had superficial weeping ulcers (these represented a chronic problem).

B.P. 95/65, P 140, T 40.3°, R 32

Pulses not palpable in left foot, but OK in right foot.

Lab: WBC 8,900, 89 % granulocytes; creatine kinase

2,410 units/Liter (nl 20-210 u/L)

Blood culture obtained.

Treated with vancomycin, ceftazidime, ciprofloxacin

Course: Over next 24 hrs, progressive hypotension oliguria, serum creatinine 3.0,

creatine kinase 6,000 u/L

Surgical and infectious disease consultation led to amputation of left leg above the knee.

Surgical specimens abundant PMNs, Gram (+) cocci in chains.

Dx: Necrotizing fasciitis without myonecrosis.

Blood cultures (+) for Group A = Streptococcus pyogenes 24 hrs after admission.

Within 48 hrs of surgery, hemodynamic status returned to normal, and healing of amputation site over next several weeks

12 y/o male - sore throat and fever (39.4° oral) which lasted 3 days

twelve days later - puffiness around eyes (periorbital edema), ankles swollen;

urine smoky, brownish appearance

PE: inflamed pharynx with exudate on enlarged, red tonsil; erythema of palate; enlarged tender cervical lymph nodes; pitting edema feet and pretibial.

BP 165/105

Lab: Urine 4+ protein, 20 to 30 RBC and 25-30 WBC/HPF hyaline granular and red cell casts, but sterile. Throat culture Group A strep (M type 12 later confirmed) ASO titer 166 units/ml (borderline), later to 500 u/ml, Serum C3

Treated with penicillin G

Seven days later: feeling better; edema, BP, output of urine , grossly normal but still microscopic hematuria

Acute Glomerulonephritis

Classic Features of Rheumatic Fever

Rheumatic Carditis

Aschoff body Anitschkow cells

Heart - Rheumatic Fever - fibrinoid

Rheumatic Fever Valvular Vegetation

1st Clinical Trial of Penicillin in the US

CAMP Test

Group B Strep.

Strep. Pneumo.Group A Strep.

Pathogenic Agents of Bacterial Meningitis According to Age GroupMeningitis due to Escherichia coli or other enteric pathogens among infants less than one month of age was not included in the surveillance

Age-specific incidence in 1995 of Bacterial Meningitis and of All Invasive Bacterial Diseases

Strategy to Prevent Group B Streptococcal (GBS) Disease in Neonates

Indications for antibiotic intrapartum (during delivery):

1. At 35 - 37 weeks gestation, do rectal and vaginal culture. If (+) for GBS.

2. If, during pregnancy, urine is (+) for GBS.

3. If woman had previous infant with invasive GBS disease.

4. If membranes rupture at < 37 weeks.

5. If membranes rupture > 18 hours before delivery.

6. If temperature > 38°C during labor.

___________________* Penicillin G (preferred) or ampicillin; cefazolin for penicillin-allergic woman;

clindamycin or erythromycin under some circumstances.

Acute bacterial (enterococcal) prostatitis

A 75 year old white male, previously in good health, with an essentially normal prostate examination one month earlier, developed a slight discomfort upon urination. His oral temperature was 36.7o C (98o F). Over the next 48 hours, frequency of urination increased, there was burning of the urethral meatus and the volume of urine with each voiding decreased. By now, his temperature rose to the range of 37.2 to 37.7o C. There was no flank tenderness. Three days after onset of his illness, a midstream specimen of urine contained a few degenerating polymorphonuclear leukocytes, but a culture yielded more than 105

organisms/ml. These appeared to represent a single colonial type of catalase negative Gram positive cocci. Further studies indicated that this was an Enterococcus species.

Oral ampicillin 500 mg twice a day led to resolution of symptoms in 6 to 7 days. After 22 days, the antibiotic was discontinued, and at that time the urine yielded no bacterial growth.

Enterococcus faecalis - antibiotic susceptibility

hours

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Vancomycin-resistant Enterococcus - trauma, burn, ICU

Structure of Oxazolidinones

Basic Oxazolidinone structure

Eperezolid

Linezolid

Glucan (dextran) Synthesis from Sucrose

Formation of Dental Plaque/Caries

enameldentin

gingival margin

pulp

cementumperiodontal ligament

alveolar bone

neurovascular bundle

plaque

sucrose glucan + fructose(glucose - fructose) (glucose)a

lactic acid

glucosyl transferase

Endocarditis - mitral valve

Endocarditis - “splinter hemorrhage,” Osler’s nodes