All receptacles (containers) for collection of specimens

must be sterile otherwise contaminants from the container

will also be grown.

Microbiology and Bacteriology 833

Urine

Organisms found in a normal urine are staphylococci

(coagulase negative), diphtheroid bacilli and coliform

bacteria. The important pathogens are Escherichia coli,

Proteus, Citrobacter, Pseudomonas, Klebsiella, Moraxella,

Acinetobacter, Staphylococcus, Streptococcus faecalis,

Salmonellae, Mycobacterium tuberculosis, etc. For nontuberculosis patients a mid-stream fresh urine specimen

is good enough. Urine samples are streaked on blood agar

and MacConkey agar plates. At the same time, microscopic

examination of the urine should also be carried out.

Catheterization is indicated only when a mid-stream

specimen (MSS) cannot be obtained, if done—all aseptic

precautions must be undertaken. Before collecting the

specimen, the area is washed well with soapy water and

dried and then the MSS collected. A Gram’s stain should

be done on the centrifuged sediment.

If tuberculous nephritis is suspected, a 24-hour

specimen, or preferably 5 consecutive early morning

specimens are sent to the laboratory. The specimens are

centrifuged and the deposits pooled. A Ziehl-Neelsen stain

is done and the deposits concentrated before culturing for

tubercle bacilli.