food poisoning

scalded skin syndrome

Toxic diseases such as toxic shock syndrome

Ordinary agar plate: medium-sized, raised, smooth, moist, and neatly edged colonies

Blood agar plate (Staphylococcus aureus): The colonies are yellow or golden, with obvious transparent β-hemolytic rings.

Broth medium: uniform turbid growth

Nurture characteristics

Specimens: feces, vomitus (digestive tract infection)

Different selections are made based on the site of infection, and infection by surrounding normal flora should be avoided.

Direct smear of sterile body fluids, such as cerebrospinal fluid

In other body fluids, not only bacteria but also inflammatory cells are found

Gram-positive Staphylococcus aureus found, suspected to be Staphylococcus aureus (descriptive language, possibility report)

Isolation culture

Identification: catalase test positive, oxidase test negative

Type A (alpha hemolysis): grass-green hemolytic ring, Streptococcus pneumoniae - opportunistic pathogens

Type B (β hemolysis): transparent, colorless hemolytic ring, purulent, agalactiae-Streptococcus agalactiae - highly pathogenic

Type C (γ hemolysis): no hemolysis ring, generally not pathogenic - Streptococcus bovis

There is no parallel relationship between the group and hemolysis, but the main pathogenic to humans is group A (type B hemolysis)

Bacterial cell wall component: M protein

Invasive enzymes: streptokinase, streptokinase, hyaluronidase

Exotoxins: Pyrogenic exotoxins (scarlet fever toxin, rash toxin). Streptolysin: SLO: Strong antigenicity, produces antibodies. SLS: No antigenicity.

purulent infection

toxin disease

allergic disease

Agalactiae (Group B) Streptococcus: neonatal infection

Viridans Streptococcus: subacute bacterial endocarditis

Streptococcus pneumoniae: Lobar pneumonia

G, spherical or oval, arranged in a chain; no spores, no flagella, some have capsules (strong pathogenicity, not easy to stain)

High nutritional requirements, grows well in 5%-10% CO2

Blood plate: gray-white, round convex, smooth surface, small colonies

Bacitracin sensitivity test: Group A screening

CAMP test: Preliminary identification of Streptococcus agalactiae (Group B) --- Streptococcus agalactiae can produce CAMP factor, which can promote the hemolytic ability of Staphylococcus aureus. The synergistic hemolysis at the junction of the two bacteria is positive.

Bile Aesculin Test: Group D

Staphylococcus and Streptococcus: Catalase test--Staphylococcus (positive), Streptococcus (negative)

Streptococcus pneumoniae and viridans Streptococcus:

Gram-positive cocci, singly, in pairs or in short chains

Higher, the optimal temperature is 35°C, and can grow at both 10 and 45°C

Off-white, smaller, round, S-shaped colonies with smooth surface, no hemolysis or occasional alpha hemolysis

Gram stain microscopy shows Gram-positive cocci arranged singly, in pairs or in short chains.

Intergeneric identification

Interspecific identification within a group

Capsule, pili, lipooligosaccharide

meningococcal meningitis

Outer membrane proteins, pili, protease, lipooligosaccharide

Adults: sexual contact; neonatal gonorrheal conjunctivitis caused by transpartum canal infection

Gram-negative diplococci, renal in nature, with opposite concave surfaces, no spores, no flagella, and most new isolates have capsules and pili.

The highest, blood or serum needs to be added to the culture medium: optimal temperature is 35°C, no growth below 30°C/above 40°C; obligate aerobic; growth in 5%-7% CO2

Neisseria meningitidis

Neisseria gonorrhoeae

Keep warm and moisturize, send for examination immediately, preferably bedside vaccination, pre-warm on tablet

microscopy

Antigen test

Both the oxidase test and the catalase test were positive

Neisseria meningitidis decomposes glucose and maltose, but not sucrose, and produces acid but no gas; Neisseria gonorrhoeae only decomposes glucose, produces acid but no gas.