Structural Comparison of Three Types of Staphylococcal Cassette Chromosome mec Integrated in the Chromosome in Methicillin-Resistant Staphylococcus aureus

Part I Antimicrobial resistance: Bacterial pathogens of dermatologic significance and implications of rising resistance

“…MRSA isolates express lowaffinity PBPs, PBP2a and PBP2c, that are encoded by the mecA and mecC genes, respectively, and carried on a mobile genetic element known as the staphylococcal chromosomal cassette. 18,20,22 Not only can the staphylococcal chromosomal cassette be readily transferred among staphylococcal species, but it can also carry other resistance genes, partially and exceed 70% in select East Asian countries. 17,23 HA-MRSA is now a leading cause of nosocomial bacteremia, pneumonia, and vascular-access-and catheter-associated infections.…”

“…Methicillin-resistant Staphylococcus aureus antibiotic options and resistance mechanisms[17][18][19][20][21][22][23] …”

Carriage of Beta-Lactamase and Antibiotic Resistance in Staphylococcus aureus

“…For many years till now, antibiotics have been employed in the treatment of Staphylococcus infections but resistance to antibiotics commonly used against them has reduced the effectiveness of the antibiotics [4,5]. Mec A gene which is located on the staphylococcal cassette chromosome enables the organism to develop resistance against antibiotics used against it [6][7][8]. An altered 75 kb penicillin binding protein 2A (PBP2a) is produced inside the mec A gene which also gives it its resistance properties to antibiotics especially the beta-lactam [9].…”

Bromomethylthioindole Inspired Carbazole Hybrids as Promising Class of Anti-MRSA Agents

“…Moreover, these compounds also possessed a broad spectrum of inhibitory activities against multiple clinically isolated MRSA strains, including M013, N043, C217, Y069, L166, Z234, and 4N216, at MIC values as low as 0.5−1 μg/mL. In contrast to the indolecontaining N-substituted carbazoles (11,12,19), compound 24 showed a higher MIC value ranging from 1 to 4 μg/mL against majority of the clinical MRSA strains tested. Structural comparison between compounds 19 and 24 suggests that the indole moiety, with the corresponding linker length, plays a vital role in the growth inhibition of the clinical MRSA strains.…”

“…2,3,7 MRSA arises when methicillin-susceptible S. aureus (MSSA) acquires a large mobile genetic element called staphylococcal cassette chromosome mec (SCCmec) through horizontal gene transfer. 11,12 Incorporation of the SCCmec leads to the expression of an altered penicillin-binding protein PBP2′ (PBP2a), which has >100-fold lower binding affinity for nearly all available β-lactam antibiotics, rendering them ineffective against MRSA. 1 Glycopeptide-based antibiotics, especially vancomycin, have been the main drug of choice for treating severe MRSA infections.…”