Pus Swabs

The infected area is carefully swabbed with spirit before

the swab is taken, or the pus aspirated. Carry out a Gram’s

stain, streak on blood agar, MacConkey agar and then place

into nutrient broth or, if anaerobes are suspected, into

thioglycollate broth or Robertson’s cooked meat medium.

In cases of suspected gangrene or tetanus: two blood agar

plates should be inoculated, one for aerobic culture and

the other for incubation in an anaerobic atmosphere.

Blood Cultures

Bacteremia is an important part of any systemic infection

and hence, blood culture acquires similar significance.

Blood culture permits the prompt commencement of

specific treatment against the offending organism and

may prove to be lifesaving.

Bacteremia occurs transiently in pneumococcal

pneumonia, bacterial meningitis, urinary tract infections,

enteric fever and generalized Salmonella infections. A

mild transitory bacteremia is a frequent finding in many

infectious diseases but a persistent bacteremia points

towards a more serious infection. When the classic

syndrome of a septicemia is due to pyogenic organism,

chills, fever prostration is found, one rarely finds difficulty

in isolation of the causative organism. In some diseases the

chances of isolating bacteria from blood culture depends

on the stage of the disease at which the culture is done. For

example, bacteria can be cultured during the early course

of the disease, thus the cultivation of the bacteria from the

blood is important since, it may be the only reliable means

of making an early diagnosis available for the physician.

A diagnosis of bacteremia can only be made by growing

the pathogenic agents on suitable culture media. Perfect

aseptic conditions must be observed while collecting

blood for blood culture. Enriched aerobic and anaerobic

culture media must be utilized in order to provide optimal

conditions for bacterial growth. Commonly isolated