How does PBP2a work?

How does PBP2a work?

PBP2A is a peptidoglycan transpeptidase that, in cooperation with the transglycosylase domain of PBP2 of S. aureus, can catalyze cell wall biosynthesis in the presence of β-lactam antibiotics, thus enabling survival and growth of the bacteria (2, 4).

How does PBP2a function in the beta lactam resistance of MRSA?

High-level resistance to β-lactam antibiotics in methicillin-resistant Staphylococcus aureus (MRSA) is due to expression of penicillin-binding protein 2a (PBP2a), a transpeptidase that catalyzes cell-wall crosslinking in the face of the challenge by β-lactam antibiotics.

What is the mechanism of resistance in MRSA?

However, the main mechanism of methicillin resistance in S. aureus is through the expression of a foreign PBP, PBP2a (not to be confused with PBP2), that is resistant to the action of methicillin but which can takeover the transpeptidation (cross-linking) reactions of the host PBPs.

Is PBP2a an enzyme?

Methicillin-resistant Staphylococcus aureus (MRSA) is one of the “superbug” family, manifesting resistance through the production of a penicillin binding protein, PBP2a, an enzyme that provides its transpeptidase activity to allow cell wall biosynthesis.

How is the mecA gene involved in the mechanism of resistance?

The epidemiologically most important mechanism of antibiotic resistance in Staphylococcus aureus is associated with mecA–an acquired gene encoding an extra penicillin-binding protein (PBP2a) with low affinity to virtually all β-lactams.

Why is MRSA resistant to beta-lactams?

The resistance of MRSA strains is caused by the acquisition of the mecA gene encoding the alternative transpeptidase penicillin binding protein 2a (PBP2a), with very low affinity for almost all β-lactam antibiotics (4,–7).

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. These mechanisms may be native to the microorganisms, or acquired from other microorganisms.

How do you read MRSA test results?

What Your Test Results Mean. If your MRSA test is positive, you are considered “colonized” with MRSA. Being colonized simply means that at the moment your nose was swabbed, MRSA was present. If the test is negative, it means you aren’t colonized with MRSA.

How is MRSA infection diagnosed?

Doctors diagnose MRSA by checking a tissue sample or nasal secretions for signs of drug-resistant bacteria. The sample is sent to a lab where it’s placed in a dish of nutrients that encourage bacterial growth.

What is the function of penicillin-binding protein?

The penicillin-binding proteins (PBPs) polymerize and modify peptidoglycan, the stress-bearing component of the bacterial cell wall. As part of this process, the PBPs help to create the morphology of the peptidoglycan exoskeleton together with cytoskeleton proteins that regulate septum formation and cell shape.

Does the presence of the mecA gene confirm MRSA?

Molecular amplification of the mecA gene is recognized as a benchmark to diagnose MRSA in the community as these genes are highly conserved among staphylococcal species [6].

Does MSSA have mecA?

Methicillin-resistant Staphylococcus aureus (MRSA) arises when methicillin-susceptible S. aureus (MSSA) acquires the staphylococcal chromosome cassette mec (SCCmec) element, which contains the mecA gene encoding an altered penicillin-binding protein, PBP2′ (PBP2a) with lowered binding affinity for β-lactams (12).

Do all MRSA have mecA gene?

All MRSA strains carry a mobile genetic element called staphylococcal cassette chromosome (SCC) which harbours the mecA gene (Figs. 37.2, 37.3) [17]. This gene encodes penicillin-binding protein 2a that confers resistance to β-lactam antibiotics.

How did MRSA develop resistance to antibiotics?

Scientists have found that genetic mutations in MRSA allow it to evolve and become more resistant to antibiotics such as penicillin. Scientists from the University of Sheffield have found that genetic mutations in MRSA allow it to evolve and become more resistant to antibiotics such as penicillin.

Why is MRSA resistant to methicillin?

Methicillin-resistant S. aureus (MRSA) poses a significant and enduring problem to the treatment of infection by such strains. Resistance is usually conferred by the acquisition of a nonnative gene encoding a penicillin-binding protein (PBP2a), with significantly lower affinity for β-lactams.

What are the five 5 most common mechanisms of drug resistance?

What are the 5 modes of action of antimicrobial drugs?

Basis of Antimicrobial Action Various antimicrobial agents act by interfering with (1) cell wall synthesis, (2) plasma membrane integrity, (3) nucleic acid synthesis, (4) ribosomal function, and (5) folate synthesis.