STREPTOCOCCUS PNEUMONIE

STREPTOCOCCUS PNEUMONIE

Morphology

Is gram + coccus, facultative anaerobic, encapsulated, catalase -, alpha hemoliticus, has no movility, is no spore former, grows in chocolate agar and has 90 serotypes.

Colonies

This bacteria formes a mucose colonia, umbilicated ( with a central depretion) and do viridans hemolysis.

Virulence Factors

Adherence: the adherence to epitellium is mediated by surface proteins.
Capsule: Allow him to elude the immune response. is the most important virulence factor.
Peptidoglicane: Lipoteicoic and teicoic acid allows to ellicit immune response and make bigger inflamation due TLR5.
Coline Phosphate: links to PAF-R and allows the cell enter into the epitellium and elude opsonization and phagocitosis.
Pneumolisine: Is a citotoxic toxine, links to cholesterol and formes pores in the membrane of PMN, monocytes and lymphocites.
Autolisine: Is a protein that clives the peptidoglicane and bring outside the Hypometylated-DNA to performe a immune response due TLR9.

Clinical Manifestations

Neumonie: It's the princiapl manifestation in children and less prevalent in adults. The symptoms include fevere, dispnea, pleuritic pain, chills, night sweat, mucopurulent spute.

Another manifestations: Meningitis, Middle otitis, osteomielitis, sinusitis.

Dx

The diagnostic is performed with clinical manifestations, X-ray and laboratory tests.

Laboratory Tests

Gram Dyeing: With the well taken sputum of the patient, the sample is carried to the laboratory, and the best sample will be the one with: many bacterias, few epitellium and very immune complexes. The culture is only performed in the gram dyeing with mored than 25 bacterias and less than 10 epitellium cells.

Culture: Is performed in chocolate, blood and Mckonkey agar; in sterile recipient.

Antibiograme: Is very useful because of penicilline resistance. Also is very useful to confirme the bacteria with the optoquidine test.

Treatment: 3d generation Cephalosporine (e.g. Ceftriaxone). In resistent infections is useful a macrolide (e.g. Azytromicine) or a quinolone (e.g. levofloxacine)