Molecular cloning of the gene of a penicillin-binding protein supposed to cause high resistance to beta-lactam antibiotics in Staphylococcus aureus

Abstract

A novel penicillin-binding protein, PBP-2' (Mr about 75,000), is known to be induced in excessively large amount by most beta-lactam compounds in cells of a clinically isolated strain of Staphylococcus aureus, TK784, that is highly resistant to beta-lactams and also most other antibiotics. This protein has very low affinities to most beta-lactam compounds and has been supposed to be the cause of the resistance of the cells to beta-lactams. A 14-kilobase DNA fragment was isolated from the cells that carried the gene encoding this penicillin-binding protein and also a genetically linked marker that is responsible for the resistance to tobramycin. This DNA was cloned on plasmid pACYC184 and was shown to cause both production of PBP-2' and resistance to tobramycin in Escherichia coli cells. However, the formation of PBP-2' in E. coli was only moderate and was independent of normal inducer beta-lactams. The PBP-2' formed in the E. coli cells showed slow kinetics of binding to beta-lactams similar to that of PBP-2' formed in the original S. aureus cells and gave a similar pattern of peptides to the latter when digested with the proteolytic V8 enzyme of S. aureus.

Tn554 inserts in methicillin-resistant Staphylococcus aureus from Australia and England: comparison with an American methicillin-resistant group

“…Earlier studies had shown that Mcr S . aureus isolates contain chromosomal DNA, amounting to 30 kb or more, which is also absent from Mcs strains (Beck et al, 1986;Matsuhashi et al, 1986;Matthews et al, 1987). This DNA contains the Mc' determinant mec and determinants for various other resistances (Skinner el al., 1988;Skurray et al, 1988;Ubukata et al, 1989).…”

In vitro antimicrobial activity of a new series of 1,4-naphthoquinones

“…This bacterium is one of the most prevalent microorganisms in nosocomial infections worldwide and methicillin-resistant strains represent 15-45% of all S. aureus isolates (36). MRSA isolates carry the mec gene, a 2130-bp DNA fragment of non-staphylococcal origin encoding a low antibiotic-affinity penicillin-binding protein (37). Since methicillin resistance was first identified in a clinical isolate of S. aureus, its incidence has increased significantly, MRSA has spread globally, and the mec gene has also been detected in several other staphylococcal species (37,38).…”

“…MRSA isolates carry the mec gene, a 2130-bp DNA fragment of non-staphylococcal origin encoding a low antibiotic-affinity penicillin-binding protein (37). Since methicillin resistance was first identified in a clinical isolate of S. aureus, its incidence has increased significantly, MRSA has spread globally, and the mec gene has also been detected in several other staphylococcal species (37,38). Specifically, S. aureus growth, including MRSA, was effectively inhibited by compound II and other derivatives, suggesting the applicability of these naphthoquinones against staphylococci.…”

Methicillin resistance in <i>Staphylococcus aureus</i>: a review of the molecular epidemiology, clinical significance and laboratory detection methods

“…In 1986, the mecA gene was cloned from a Japanese MRSA strain and its sequence was determined. 32 This gene was found to be widely distributed among S. aureus as well as coagulase negative staphylococci. It was hence speculated that the mec determinant must be freely transmissible among staphylococcal species.…”