In the name of God. Diagnostic microbiology. Background. Microbiology is the study of cellular and acellular cells and agents. Cellular micro-organisms are consisted of prokaryotics bacteria and archea- and eukaryotics such as fungi (yeat, moulds) , protoza, and algae.
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these are assumptions about their role in renal stone formation and some form of atherosclerosis.
and some of these virulence factors may be acquired by genetic phenomena like transformation, genetic transduction (Scarlet fever toxin, diphtheria toxin and genetic conjugation, transfer of resistant factors.)
dermatophytes: which produce infection in hair, nail and skin such as epidermophyton trichophyton, candida yeast.
Fungi which can cause mucosal infection such as mucromycosis, asperiogillus
Fungi which can cause systemic infection such as yeast, histoplasma capsulatum etc,…
Malaria: plasmodium species
Leishmania species (kala-azar, mucocutonous infection)
Ciliate: Balantidium coli
Flagellate: Trichomonas, Giardia
Prions: prions are protein in naturre. When their tertiary structure is change due to mutation, it becomes infectious.
Prions are assumed to be the cause degerative disease of nerve cells.
prions are the causative agents of certzfeid Jacob syndrome in human.
Madcow disease in cow and cattles.
Scrapies in sheep and goats.
In the suspected case of salmonellosis typhoid and paratyphoid-take a blood culture in the first week of infection.
Serology test in the end of the second week and urine and stool culture during the second and third week may show positive result.
for culture in order to isolate the suspected
In every case try to obtain blood for culture before
antibiotic therapy. If this is not unavoidable try to
use culture media which contains resins to bind to
the suspended antibiotics.
Once an infectious disease is suspected and after
physician request for specimen collection all
quality criteria should carried out.
Although culturing and isolation of the infecting
microbe is the gold standard there are situations in
which the pathogen can’t be isolated by routine
culturing methods and media.
state of VBNC meaning that although the bacteria
are alive (viable) but nonculturable.
The change in the PH of infected site may cause decrease
in viability and although presence of many enzymes
produced by the inflammatory cells (peroxidases,
phospholipases, RNAes, DNAes) may result in
destruction of microbes.
In the case of wound infectious first cleans the superficial pus and dirt by alcohol and then if the wound is open draw the specimen from edge of the infection sites without touching the adjacent skin.
In the case of UTI suspected patient, the best way is to obtain a clean cached early morning mid stream urine or any urine remained in the bladder at least for 4 hours.
Suprapubic urinecollection should be remained for very small children in which collection of CVU is not possible to them.
In case of streptococcal pharynsitisthe peritonsillar fossae and postpheraryngeal wall is swabed
It is better that patient have had a mouth wash and after that a deeply coughed sputum be taken in wide mouth sterile container.
In the case of any deeply seated abcess or pus loculation, the best way of specimen collection is by aspiration.
In the case of otitis media, carefully enter a sterile swab toward the site of infection.
In the case of meningitis- after LP done by physician transport the tube, as soon possible and centrifuge the content of the second tube for culturing and smear .
This is a physician or an oriented HCW to take specimen from the actual site of infection
As it is possible do not mix the specimen with micriflora present in the site.
As it is possible try to take specimen before any chemotheraputic (antibiotic) are used.
As soon as possible transfer the specimen to the lab, in a safe manner