Why is Gram-negative bacteria more resistant to antibiotics than Gram positive?

Any alteration in the outer membrane by Gram-negative bacteria like changing the hydrophobic properties or mutations in porins and other factors, can create resistance. Gram-positive bacteria lack this important layer, which makes Gram-negative bacteria more resistant to antibiotics than Gram-positive ones [5,6,7].

Why does Erythromycin work better on Gram positive bacteria?

Gram-positive bacteria accumulate about 100 times more erythromycin than do gram-negative microorganisms. The non ionized from of the drug is considerably more permeable to cells, and this probably explains the increased antimicrobial activity that is observed in alkaline pH.

How do bacteria become resistant to macrolides?

Bacteria resist macrolide and lincosamide antibiotics in 3 ways: (1) through target-site modification by methylation or mutation that prevents the binding of the antibiotic to its ribosomal target, (2) through efflux of the antibiotic, and (3) by drug inactivation.

What are the major differences between Gram positive and Gram negative bacteria?

Gram positive bacteria have a thick peptidoglycan layer and no outer lipid membrane whilst Gram negative bacteria have a thin peptidoglycan layer and have an outer lipid membrane.

Why are gram positive bacteria typically more resistant than Gram negative bacteria to antimicrobials that disrupt plasma membranes such as polymyxin B?

Antimicrobials targeting the bacterial outer membrane and cell wall. Gram-negative bacteria tend to be more resistant to antimicrobial agents than Gram-positive bacteria, because of the presence of the additional protection afforded by the outer membrane.

Why are gram positive bacteria more heat resistant?

Gram-positive organisms tend to be more resistant to drying due to their thicker cell wall, but more susceptible to cleaning agents due to lack of an outer membrane.

Is erythromycin effective for Gram-positive or negative?

Erythromycin has a similar spectrum of activity to broad-spectrum penicillins and is often used for treating individuals who are allergic to penicillin. It is effective against Gram-positive bacteria and gut anaerobes but has poor activity against H. influenzae.

Is erythromycin effective against gram-negative bacteria?

The first 14-membered macrolide, erythromycin A, has been in clinical use since 1952. Erythromycin is active against Gram-positive and some Gram-negative microorganisms and is used in treatment of respiratory, gastrointestinal, and genital tract infections, as well as skin and soft tissue infections [18].

What is the primary mechanism of resistance of S pneumoniae to macrolide antibiotics?

In S. pneumoniae, macrolide resistance is due to ribosomal dimethylation by an enzyme encoded by erm(B), efflux by a two-component efflux pump encoded by mef (E)/mel(msr(D)) and, less commonly, mutations of the ribosomal target site of macrolides.