Disease relevance of blaZ

• In contrast to most Staphylococcus aureus isolates in which the gene for staphylococcal beta-lactamase (blaZ) is plasmid borne, isolates typeable by group II bacteriophages frequently carry blaZ on the chromosome [1].
• Diversity and evolution of blaZ from Staphylococcus aureus and coagulase-negative staphylococci [2].
• This E. coli clone harbored a recombinant plasmid (pAH12) containing two different staphylococcal HindIII inserts (7.0 and 5.3 kb), of which only the former hybridized with a blaZ probe [3].
• We report another Bla+ enterococcus with high-level gentamicin resistance [4].
• Fifty-eight penicillin resistant Staphylococcus aureus isolates of known phage types from bovine mastitis in Denmark from the 1950'ties (10 isolates) and the 1990'ties (48 isolates) were tested for beta-lactamase production [5].

Psychiatry related information on blaZ

• S1 reaction times were approximately 50% faster than nitrocefin for beta-lactamase-positive enterococci and S. aureus [6].

High impact information on blaZ

• Tolerance is thus a common, clinically important form of penicillin resistance, that differs from previously described forms of pencillin resistance, that due to beta-lactamase, and that due to "intrinsic" (e.g., methicillin resistance) mechanisms [7].
• In the second type of fusion, blaZ was translationally fused to the C-terminal end of repC [8].
• Borderline resistance, a low-level type of resistance to methicillin exhibited by strains lacking mecA, is associated with modifications in native PBPs, beta-lactamase hyperproduction, or possibly a methicillinase [9].
• The resistance phenotype is influenced by numerous factors, including mec and beta-lactamase (bla) regulatory elements, fem factors, and yet to be identified chromosomal loci [9].
• One approach to counteracting this resistance mechanism has been through the development of beta-lactamase inactivators. beta-Lactamase inhibitors include clavulanic acid and sulbactam, molecules with minimal antibiotic activity [10].

Chemical compound and disease context of blaZ

• The blaZ gene contained in a single 17.2-kb beta-lactamase plasmid from a borderline methicillin-susceptible Staphylococcus aureus strain (a53) has been cloned in Escherichia coli [3].
• beta-Lactamase-mediated inactivation and efficacy of cefazolin and cefmetazole in Staphylococcus aureus abscesses [11].
• The prevalence of beta-lactamase-producing bacteria in subgingival plaque from patients with refractory periodontitis in Norway was assessed by the chromogenic nitrocefin method. beta-Lactamase activity was detected in 68% of the patients [12].
• The genes encoding for beta-lactamase (bla+) and resistance to metallic ions (cadmium, mercury, lead, arsenate, and arsenite) were located in a 56.2-kilobase plasmid, pZA10, isolated from a clinical strain, Staphylococcus aureus 6344 [13].
• beta-Lactamase production protects Staphylococcus aureus against piperacillin and amoxycillin [14].

Biological context of blaZ

• We have prepared and analyzed two types of gene fusion between the replication initiator gene, repC, and the reporter gene, blaZ, in order to investigate the relationship between pT181 plasmid copy number and RepC initiator protein production [8].
• In one type of gene fusion used in this study, blaZ was translationally coupled to the C-terminal end of the repC coding sequence such that native forms of both proteins were produced [8].
• The plasmids harboring both qacA/B and blaZ genes varied from approximately 20 to 40 kb [15].
• In all eight type B beta-lactamase-producing isolates, blaZ was located on the chromosome [1].
• Although a common gene pool seems to exist among staphylococci, exchange of blaZ between strains and species is judged to be an extremely rare event [2].

Anatomical context of blaZ

• These bacteria were all isolates of S. aureus (11) and B. fragilis (2), 8 of 22 B. melaninogenicus group, 4 of 11 B. oralis, and two of 8 H. influenza type B. Our findings indicate the polymicrobial nature of deep adenoid flora and demonstrate the presence of many beta lactamase-producing organisms in children with recurrent adenotonsillitis [16].
• METHODS: beta-Lactamase activity of whole cells and purified enzymes was estimated spectrophotometrically and in isolated cytoplasmic membranes by bioassay with Bacillus subtilis as test strain [17].
• Emergence and persistence of beta-lactamase-producing bacteria in the oropharynx following penicillin treatment [18].
• Beta-lactamase production was noted in 56 isolates recovered from 37 tonsils [19].
• Overall, the excellent activity of imipenem is the result of (1) the lack of a permeability barrier; (2) high affinity for PBP-2, a critical protein in cell wall synthesis in gram-negative bacteria, and for critical penicillin-binding proteins of gram-positive species; and, above all, (3) its great beta-lactamase stability [20].

Associations of blaZ with chemical compounds

• MecI (methicillin repressor) blocks mecA but also blaZ transcription and that of itself and the co-transcribed sensor/transducer [21].
• We conclude that type A blaZ is common in MSSA PJI and that cefazolin therapy for blaZ MSSA PJI can be successful when combined with 2-stage reimplantation and local antimicrobial therapy [22].
• Testing beta-lactamase production with nitrocefin was more predictive for the presence of the blaZ gene than the agar dilution method and the results of the former agreed highly with the presence of the blaZ gene in the isolates [23].
• N-Carboxylated lysine also catalyzes hydrolytic deacylation of the acyl-enzyme species in the beta-lactamase [24].
• Susceptibility and bactericidal activity studies of four Bla+ enterococci against potential alternative antibiotics, including ampicillin-sulbactam, daptomycin, teicoplanin, and vancomycin, are presented [4].

Other interactions of blaZ

• Complete pbp2 sequences were determined for three BORSA, corresponding to ST25, ST1 and ST47, which were selected on the basis of lacking blaZ-encoded beta-lactamase [25].
• RESULTS: All penicillin-resistant strains carried blaZ and showed a similar organization of blaR1 and blaZ [2].
• Furthermore, the presence of blaZ and blaR1 and the location of blaZ was determined by PCR and hybridisation [5].
• A novel plasmid (designated pUB102) harbouring far1, tetK and blaZ was characterised and partially sequenced [26].
• Southern hybridisation analysis indicated that sin is located on alpha-, beta- and gamma-families of Bla plasmids and on pSK1 family plasmids [27].

Analytical, diagnostic and therapeutic context of blaZ

• The localization of blaZ was determined by Southern blotting in 108 isolates [2].
• PCR revealed 4 isolates without blaZ, and 12 with type A, 2 with type B, and 5 with type C blaZ [22].
• Sequence analysis of an internal region of blaZ in 2 isolates of bovine origin showed a high degree of homology to already published sequences from human isolates [5].
• 12694668 Clinical reports and animal models have demonstrated that cefazolin may have decreased efficacy against some strains of Staphylococcus aureus because of type A beta-lactamase-mediated hydrolysis [11].
• Association of cefazolin treatment failure with type A beta-lactamase-producing Staphylococcus aureus has been suggested [22].

References