Acquired antimicrobial resistance is
the result of an evolutionary process by which microorganisms adapt to antibiotics through several mechanisms
including alteration of drug target by mutations and horizontal transfer of novel/foreign genes, referred to as resistance genes.
How acquired resistance is produced?
As it will be discussed later in the chapter, the development of acquired resistance can be the result
of mutations in chromosomal genes
or due to the acquisition of external genetic determinants of resistance, likely obtained from intrinsically resistant organisms present in the environment.
What is the difference between intrinsic and acquired resistance?
Intrinsic resistance is the innate ability of a type of bacteria species to resist the action of an antibiotic as a consequence of the bacteria’s structural or functional characteristics. In contrast to acquired resistance, which you will look at next, intrinsic resistance is
‘normal’ for bacteria of a given type
.
How does acquired resistance work?
Acquired resistance
results from successful gene change and/or exchange that may involve mutation or horizontal gene transfer via transformation, transduction or conjugation. A mutation
is
a spontaneous change in the DNA sequence within the gene that may lead to a change in the trait which it codes for.
What is an example of acquired antibiotic resistance?
Some examples of the link between antibiotic dosage and resistance development are the rise of
methicillin-resistant Staphylococcus aureus (MRSA)
and vancomycin-resistant enterococci (VRE).
What are the five general mechanisms of resistance?
The main mechanisms of resistance are:
limiting uptake of a drug, modification of a drug target, inactivation of a drug, and active efflux of a drug
.
What is the most common type of antimicrobial resistance?
MRSA
is one of the most common antibiotic-resistant bacteria.
How is antibiotic resistance acquired?
There are two main ways that bacterial cells can acquire antibiotic resistance. One is
through mutations that occur in the DNA of the cell during replication
. The other way that bacteria acquire resistance is through horizontal gene transfer.
How can we prevent antibiotic resistance?
There are many ways that drug-resistant infections can be prevented:
immunization, safe food preparation, handwashing, and using antibiotics
as directed and only when necessary. In addition, preventing infections also prevents the spread of resistant bacteria.
What are the five mechanisms of antimicrobial resistance?
Acquired antimicrobial resistance generally can be ascribed to one of five mechanisms. These are
production of drug-inactivating enzymes, modification of an existing target, acquisition of a target by-pass system, reduced cell permeability and drug removal from the cell.
How does drug resistance occur in an individual?
The evolution of drug resistance is facilitated by a number of factors, including
increasing use of antibiotics and antimalarials
; insufficient controls on drug prescribing; inadequate compliance with treatment regimens; poor dosing; lack of infection control; increasing frequency and speed of travel, which lead to the …
Does antibiotic resistance go away?
Without the selective pressure of antibiotics killing off the competition, bacteria with
this mutation should disappear over time
. But when the genes responsible for resistance can also be swapped between cells, the equation gets more complicated.
What is a natural resistance?
Abstract. Natural resistance to infection, which does not depend on antibiotics, is
a powerful protective mechanism common to all mankind
that has been responsible for the survival of our species during countless millennia in the past.
What infections do not respond to antibiotics?
- Sinusitis. Many patients who develop nasal congestion, sinus pressure, a sinus headache and a runny nose think that if they get a prescription for antibiotics, they’ll feel better faster. …
- Bronchitis. …
- Pediatric Ear Infections. …
- Sore Throats.
What are the types of drug resistance?
- Mono-resistance: resistance to one first-line anti-TB drug only.
- Poly-resistance: resistance to more than one first-line anti-TB drug, other than both isoniazid and rifampicin.
- Multidrug resistance (MDR): resistance to at least both isoniazid and rifampicin.
What is the difference between multidrug resistance and cross resistance?
Multidrug-Resistant Microbes and Cross Resistance
MDRs are colloquially known as “superbugs” and carry one or more resistance mechanism(s), making
them resistant to multiple antimicrobials
. In cross-resistance, a single resistance mechanism confers resistance to multiple antimicrobial drugs.
