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Necrotizing fasciitis

Streptococcal infections that start in the skin can sometimes spread elsewhere, resulting in a rare but potentially life-threatening condition called necrotizing fasciitis , sometimes referred to as flesh-eating bacterial syndrome . S. pyogenes is one of several species that can cause this rare but potentially-fatal condition; others include Klebsiella , Clostridium , Escherichia coli , S. aureus , and Aeromonas hydrophila .

Necrotizing fasciitis occurs when the fascia, a thin layer of connective tissue between the skin and muscle, becomes infected. Severe invasive necrotizing fasciitis due to Streptococcus pyogenes occurs when virulence factors that are responsible for adhesion and invasion overcome host defenses. S. pyogenes invasins allow bacterial cells to adhere to tissues and establish infection. Bacterial proteases unique to S. pyogenes aggressively infiltrate and destroy host tissues, inactivate complement, and prevent neutrophil migration to the site of infection. The infection and resulting tissue death can spread very rapidly, as large areas of skin become detached and die. Treatment generally requires debridement (surgical removal of dead or infected tissue) or amputation of infected limbs to stop the spread of the infection; surgical treatment is supplemented with intravenous antibiotics and other therapies ( [link] ).

Necrotizing fasciitis does not always originate from a skin infection; in some cases there is no known portal of entry. Some studies have suggested that experiencing a blunt force trauma can increase the risk of developing streptococcal necrotizing fasciitis. Nuwayhid, Z.B., Aronoff, D.M., and Mulla, Z.D.. “Blunt Trauma as a Risk Factor for Group A Streptococcal Necrotizing Fasciitis.” Annals of Epidemiology (2007) 17:878–881.

a) skin with large black, grey and red regions. b) Cut skin in surgery.
(a) The left leg of this patient shows the clinical features of necrotizing fasciitis. (b) The same patient’s leg is surgically debrided to remove the infection. (credit a, b: modification of work by Piotr Smuszkiewicz, Iwona Trojanowska, and Hanna Tomczak)
  • How do staphylococcal infections differ in general presentation from streptococcal infections?

Part 2

Observing that Sam’s wound is purulent, the doctor tells him that he probably has a bacterial infection. She takes a sample from the lesion to send for laboratory analysis, but because it is Friday, she does not expect to receive the results until the following Monday. In the meantime, she prescribes an over-the-counter topical antibiotic ointment. She tells Sam to keep the wound clean and apply a new bandage with the ointment at least twice per day.

  • How would the lab technician determine if the infection is staphylococcal or streptococcal? Suggest several specific methods.
  • What tests might the lab perform to determine the best course of antibiotic treatment?

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Pseudomonas Infections of the skin

Another important skin pathogen is Pseudomonas aeruginosa , a gram-negative, oxidase-positive, aerobic bacillus that is commonly found in water and soil as well as on human skin. P. aeruginosa is a common cause of opportunistic infections of wounds and burns. It can also cause hot tub rash , a condition characterized by folliculitis that frequently afflicts users of pools and hot tubs (recall the Clinical Focus case in Microbial Biochemistry ). P. aeruginosa is also the cause of otitis externa ( swimmer’s ear ), an infection of the ear canal that causes itching, redness, and discomfort, and can progress to fever, pain, and swelling ( [link] ).

Questions & Answers

what is prokaryotes
PRALHAD Reply
are micro-organisms that have no nucleus e.g bacteria
Foster
and they do not possess membrane bound organelles e.g mitochondria
Bharat
yes
Foster
they are single cellular organisms,
Rajasekhar
all the organelles are embedded in cytoplasm of the cell
Rajasekhar
They don't possess true nucleus
PREMI
they're unicellular organisms
Kamaluddeen
they are classified as bacteria and. archaea. bacteria have a cell membrane conposed of peptidoglycan and archaea is composed of psuedomu
Tara
pseudomurein
Tara
organelles are non membraneous as the nucleus
Tara
What is the biosynthesis of a bacteria cell
Adesina Reply
biosynthesis is multiple step enzymes catalyze process which occur in bacterial cell
Jayeeta
biological way of manufacturing food and utilizes it for growth, multiplication and development
Kamaluddeen
prokaryot
PRALHAD
what is microbiology
Kiirya Reply
which organism can not be seen necked eyes is knowm as microbiology
meet
microorganisms
Jayeeta
micro can be define as d smallest living organisms dat can not be see wit naked eyes only with the aid of a microscope 🔬
muhammed
bio means life logy means study
muhammed
biology can b define as the systematic study of living things
muhammed
microbiology can be define as the study of tiny organisms, that's according to my understanding
muhammed
Microbiology is the study of living organisms which cannot be seen by the naked eye but only with the aid of a microscope. These microorganisms can be classified as bacteria, fungi, micro-algae, protozoa and virus.
Tatz
microbes that can't seen in naked eyes. upto 100micrometer we can see in naked eyes but 1 microns or nanometers are invisible in naked eye.
Jayeeta
what is a cell
Oteri Reply
cell can be define as smallest indivisible organism in the body
muhammed
cell is the smallest unit which makes up the whole body
Yue
cell is smallest unit and there are two types prokaryotic cell and eukaryote cell. bacteria a prokaryotic cell which works independently.
Jayeeta
nice forum
muhammed
Which parasite competes with the host for vitamin B12 to cause pernicious anaemia
Abubakar
Diphyllobothrium latum for vit B12
Jayeeta
it is also fish tapeworm
Jayeeta
Diphyllobothrium sp feed vitB 12
Jayeeta
recent trends in microbiology of biofertilizer
Ykomalipriya Reply
using nano technology
Jayeeta
what is transposors
EMMANUEL Reply
Junk DNA, jumping gene.
Pradeep
transposon elements are jumping gene as DNA sequence move from one location to anothet
Jayeeta
Yes
Pradeep
what is microbiology
Usama Reply
Microbiology is the study of organisms, most of which are too small to be seen with the naked eye, including bacteria, algae, protozoa, and fungi, as well as acellular agents, such as viruses and prions.
digvijaya
what is gram +ve and gram - ve bacteria?
Sharma
gm- contain lipid layer so it take counter stain during gram staining and pink or red in color but gm + does have thick LPS layer.
Jayeeta
what year microbiology started
Kartik
Robert Koch was the first to detect microorganisms
Jayeeta
what appears microorganisms
Kartik
clear the questions please
Jayeeta
was it robert koch or robert hooke?
digvijaya
microbiology word came from microns. study microbes that not recognize in naked eyes.
Jayeeta
what are the branch of microbiology
Oyemade Reply
We can basically classify into pure and applied microbiology
Ozzie
what is arabinose operon and it's stucture
Pooja Reply
The L-arabinose operon, also called the ara or araBAD operon, is an operon required for the breakdown of the five-carbon sugar, L-arabinose, in Escherichia coli
Tharra
kya hum operon ko divide kar skate hain
Kartik
reactions if viruses to physical and chemical agents?
VICTOR Reply
All viruses contain the following two components: 1) a nucleic acid genome and 2) a protein capsid that covers the genome. Together this is called the nucleocapsid. In addition, many animal viruses contain a 3) lipid envelope. The entire intact virus is called the virion.
Asali
assume you have performed a gram stain on a sample of pus from a patients urethra. you see red, nucleated cells and purple rods. what can you conclude
Petty Reply
bacteria
ABUBAKAR
gram negative bacteria hence gonococcal infection
Kiirya
Study of micro organisation which we cannot see with naked eye...
shyam Reply
Despite their bad reputation, microbes are mostly beneficial or have a neutral effect on our lives. Microbiology is the scientific study of these microorganisms. Microorganisms are those organisms that are too small to see with the naked eye and include things like bacteria, fungi, and viruses.
Asali
yes
Dhirender
not 'things'...'organisms' like bacterias, viruses and fungi
Sinmi
simi, it's not bacterias but bacteria which is the plural form of the word while bacterium is the singular of it
Richard
bacterium is obvio in a singular form but plural of bacterium is bacterias
Sinmi
Richard is right it's bacterium which is the singular form and plural is bacteria. *Bacterias* doesn't exist.
Aakriti
that is microbiology which is deals with microbes only their structure
Kiirya
what is microbiology?
Sandeep Reply
what is microbiology
Glory
is the study of small microorganisms that can't be viewed by our naked eyes under a microscope
Nabukwasi
it's the study of microbes their classification, diversity, their cellular structure and processes, their applications and interaction with other organisms.
Chaitanya
what is EMP pathway
rajesh
which organism is implicated in meningoencephalitis
Peter Reply
Herpes virus
Carlos
Yeah
Laxmi
which mold is called dairy mold?
Gopinath
mushroomm
Top
Geotrichum candidum
Gopinath
hi
bio
Hlw
Laxmi
which infectious agent is the smallest
Sinmi
spore or virus
Anushree
prion ....it is a single protein in a misfolded form..there is also a theory based on it
Sinmi
yup...m sry
Anushree
yes it can be turned as a virus
Sinmi
which gram positive bacteria is responsible for food poisoning?
Sinmi
prion is not a living organism yet it is infectoois why
Jeevan
prions are virus like organism. and it is a misfolded protein that may cause disease to us.
Tharra
Clostridium perfringens, B.cereus
Sneha
Who is the father of the biology
Dhirender
I have one more question. . that who is the father of botany and medicine? ? can any one tell
Dhirender
define polar bond in simple way
Rashmi Reply
when there is formation of positive and negative poles i.e. one atom is +ve and other is -ve which further results in the dipole moment. Such bond is know as polar bond. It is a convalent bond only.
Aakriti
Practice MCQ 4

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Source:  OpenStax, Microbiology. OpenStax CNX. Nov 01, 2016 Download for free at http://cnx.org/content/col12087/1.4
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