The test consists of mixing loopful of the colony

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pneumococcus Kenneth Todor, Candidate

pneumoniae is a normal inhabitant of human >> << upper respiratory tract. This bacterium can cause pneumonia, usually

partial type paranasal sinusitis and otitis media or meningitis, which

, usually secondary to one of the former infections. He also

causes osteomyelitis, septic arthritis

, endocarditis, peritonitis, cellulitis and abscesses of the brain. Streptococcus

pneumonia is currently the leading cause of invasive bacterial disease

in children and the elderly. Streptococcus

pneumonia known in medical microbiology, as pneumococcus,

referring to their morphology and consistent participation in

pneumococcal pneumonia.

Pneumonia is a lung disease that is caused by >>

<< various bacteria, including Streptococcus, Staphylococcus, Pseudomonas, Haemophilus

,

chlamydia and mycoplasma,

several viruses and some fungi and protozoa

. disease can be divided into two forms of bronchial pneumonia

and lobar pneumonia. Bronchial pneumonia is most common in children

small children and the elderly. It is caused by various bacteria, including

Streptococcus pneumonia. Bronchial pneumonia involves the alveoli adjacent to bronchioles

more of the bronchial tree. Partial pneumonia are more likely

occur in young adults. The majority (80%) cases of partial

pneumonia caused by pneumococcus. Lobar pneumonia

includes all of one lobe of the lungs (although more than one share

may be involved), and the whole area of ​​the part to be the

consolidated mass, in contrast to the spongy structure of normal lung tissue> ;>. Gram-positive cells << pneumococcus,

lanceolate cocci (elongated cocci with slightly pointed outer curvature). Typically, they are a pair

cocci (dyplokokkov), but they can also occur separately

and in short chains. When cultured on blood agar, they are alpha-hemolytic

. Individual cells of 0. 5 and 1. 25 micrometers in diameter >>.

<< They do not dispute form and they are fixed. Like other streptococci, they lack

catalase and ferment glucose to lactic acid. Unlike streptococci Further

,

they do not see M protein, hydrolyzed inulin they, and their cell wall composition

characterized both in terms of their peptidoglycan

and teyhoevye acid. Gram film of sputum >> << s with lobar pneumonia. CDC. Pneumococcus is demanding bacteria that grow best in

5% carbon dioxide. Almost 20% of fresh clinical isolates require fully

anaerobic conditions. In all cases, growth requires a source

catalase (eg, blood) to neutralize the large amount of hydrogen peroxide

produced by bacteria. In complex media containing blood on

37C,

bacterium has a doubling time of 20-30 minutes. On agar, pneumococci grow as shiny colonies about 1 mm in diameter

.

Two serotypes, type 3 and 37, are mucous. Pneumococcus

spontaneously are genetically determined, the phase change from opaque to transparent

colonies of 1 to 10. Transparent colony type

adapted to colonize the nasopharynx and opaque

version suitable for survival in the blood. Chemical basis >> << difference in colony appearance is not known, but a significant difference in

surface protein expression between the two types was shown. Pneumococcus is aerotolerant anaerobic enzymatic >>. << Usually cultivated in media containing blood. On blood agar, colonies typical

produce a zone of alpha (green) hemolysis, which distinguishes

S. pneumonia from group A (beta-hemolytic), Streptococcus, and do not

kommensalnyh of alpha-hemolytic (viridens) streptococci, which together

residents of the upper respiratory tract. Special tests, such as inulin fermentation

bile solubility and optochin (antibiotic) sensitivity should be

commonly used to differentiate pneumococcus from Streptococcus

viridens. Pneumococcus

gram stain of blood culture broth. CDC. Pneumococcus is very fragile and bacteria

contain enzyme resolution disrupt and destroy cells

. The enzyme responsible is called

autolysin.

Physiological role of this autolysin is the cause of culture are characterized

avtolyza that kills the entire crop in the stationary phase. Almost

all clinical isolates of pneumococci harbor this autolysin and undergo lysis

usually begins between 18-24 hours after initiation of growth >> << under optimal conditions. Avtolyz consistent with changes in the morphology of the colony

. Colonies initially appear to plateau-type morphology

,

then begin to break down in the center, starting time avtolyza. Minimum criteria for identifying differences

pneumococci from other streptococci bile or optochin sensitivity gram

painting, and hemolytic activity. Pneumococci cause alpha hemolysis on

agar containing horse, human, rabbit and sheep erythrocytes. Under anaerobic conditions

they go into beta-hemolysis caused by oxygen labile

agglutinin. Typically, pneumococci form 16-mm zone of inhibition around 5 mg

, optochin disk

and pass lysis of bile salts (eg dezoksyholat). Add a few drops strattera prescription

10% at 37C dezoksyholat lysed all cultures within a few minutes.

Dezoksyholat ability to dissolve the cell wall depends on the availability

autolytic enzyme summer. Almost all clinical strains of pneumococcus >> << harbor autolysin and undergo dezoksyholat >> << lysis. Mucous pneumococcus strain on blood agar showing alpha hemolysis (green zone surrounding the colony

). Note the zone of inhibition around the filter paper disc impregnated with

optochin. Viridens streptococci are not inhibited optochin. The reaction capsule swelling reaction (swelling reaction) is the basis of serotype

and depends on the swelling of the capsule upon binding

homologous antibodies.

The test consists of mixing loopful of colony

level of specific antisera and microscopic study

at 1000X for capsular swelling. Although generally very specific,

cross-reactivity observed between capsular type 2 and 5, 3 and 8, 7 and 18, 13 and 30

, and

E. coli, Klebsiella, H. Influenza

Type B, and

certain viridens streptococci. Pneumococcus capsule swelling reaction (capsular swelling) reaction can be used to demonstrate the presence of capsule << >> specific type of bacteria. Kenneth Todor, Ph.D. All rights reserved. - WWW. textbookofbacteriology. Net >>. <<