Question

answer the two question below

bitulous puper which was used fight after the other stanny a Also, using sterilized loop could impct on this step pure cacturing. If both Gram-positive-stained and Gram-negative-stained cells are visible in the smear, cap you will take to make sure that a given bacterial strain is nure and is a Gram variable and not a mac culture. Suggest differences between the lung tissues infected with Streptococcus pneumoniae and Klebsiella pneu- monia, respectively, that Hans Christian Gram would have observed using his own developed Gram stain.

Answer 1

The presence of both gram-positive and gram-negative bacteria in smear needs some QC investigation before reporting, which are discussed below:

1. Quality of smear: Thick smear may contain an area in the slide, which are under decolourised (seen Gram-positive bacteria) and over decolourized (seen Gram Negative) bacteria. If it happens then make the fresh smear and repeat the staining.

2.   QC check of Gram Stain: It might be due to bad quality of Gram Stain. Use a smear of E.coli (Gram Negative) and Bacillus Subtilis (Gram-Positive) bacteria and perform the Gram staining, if false results come, then replace the stain and repeat the same procedure.

3. Some species of Clostridium shows gram-variable characteristics, appear as gram-negative on smears prepared from clinical samples and shows as Gram Positive, if smear made form laboratory culture.

Thus, after using these points, it may get the solution to your problem, if not then prepare smear from mother culture.

Klebsiella pneumoniae is a Gram-negative, rod-shaped,  facultative anaerobic bacteria, while Streptococcus pneumoniae is  Gram-positive cocci (usually elongated cocci seen in pair). So it is clearly differentiated using smear Microscopy And Gram Staining.