Questions

Questions from our friend "Hamad Hamoud" from Libya:

Q1 : Rheumatic fever donot diagnosis by blood culture
Q2 : The adult vagina resists infection

Q3 : Why in diagnosis of puerperal sepsis and gonorrhea take cervical swab not vaginal swab

Answers:

Q1 : Rheumatic fever donot diagnosis by blood culture

It is one of the complications of Strept.Pyogens infection "post streptococcal complication"

Caused by immunological reaction "hypersensitivity type II"

due to cross antigenicity between M protien , which present in the strept. cell wall and another protien present in our connective tissues "especially joints and valves"

So, the Antibodies formed against M protien of the bacteria can attack our protien in joints and heart.

So ... the cause of the disease is the Antibodies not the organism

which can't be detected by blood cultur "like bacteria" but to be detected serologically "ASOT"

 

Q2 : The adult vagina resists infection

this is due to many causes:

1. Type of epithelial cells in Adult is completly different from younger females due to estrogen effect.

2. pH of Adult vagina also is completly different from younger females , which is also ia a protective factor.

3. Bacterial flora in Adult vagina like lactobacillus, diphtheroids and Staphylococcus epidermidis.

These bacterial flora shares in protection of the adult vaginal by many ways like:

A. Keeping the pH acidic , which in not suitable for pathogenic bacteria.

B. occupation of the cells surface, so the pathogenic can't find a place to attach to it to clonize.

C. Some of these normal flora produce antibiotic like substances that kill pathogenic bacteria.

D. Competion on nutrents, normal flora eats from the surface of the vaginal cells , do the pathogenic can't find a nutritional source.

Q3 : Why in diagnosis of puerperal sepsis and gonorrhea take cervical swab not vaginal swab

Simply, Vagina contains normal bacterial flora, which can grow in your culture making disturbance in your diagnosis, so, you are trying"by taking cervical samples not vaginal" to minimize the contamination of your sample
But, mostly "practically" it is so difficult to take cervical samples especially in girls, so you can use the available sample.