The bla and mec families of β-lactam resistance genes in the genera Macrococcus, Mammaliicoccus and Staphylococcus: an in-depth analysis with emphasis on Macrococcus

Abstract

β-Lactamases (Bla) and low-affinity penicillin-binding proteins (PBP2A) are responsible for β-lactam resistance in the genera Macrococcus, Mammaliicoccus and Staphylococcus. These resistance mechanisms are in most species acquired through mobile genetic elements that carry a blaZ-like β-lactamase gene for penicillin resistance and/or a mec gene (mecA, mecB, mecC, mecD) encoding a PBP2A for resistance to virtually all classes of β-lactams. The mecA and mecC genes can be acquired through staphylococcal cassette chromosome mec (SCCmec) elements in Staphylococcus and Mammaliicoccus. The mecB and mecD genes are found in Macrococcus on SCCmec elements, as well as on unrelated mecD-carrying Macrococcus resistance islands (McRImecD) and large mecB-carrying plasmids. This review provides a phylogenetic overview of Macrococcus, Mammaliicoccus and Staphylococcus species and an in-depth analysis of the genetic structures carrying bla and mec genes in these genera. Native bla genes were detected in species belonging to the novobiocin-resistant Staphylococcus saprophyticus group and Mammaliicoccus. The evolutionary relatedness between Macrococcus and Mammaliicoccus is illustrated on the basis of a similar set of intrinsic PBPs, especially, the presence of a second class A PBP. The review further focuses on macrococcal elements carrying mecB and mecD, and compares them with structures present in Staphylococcus and Mammaliicoccus. It also discusses the different recombinases (ccr of SCCmec) and integrases (int of McRI) that contribute to the mobility of methicillin resistance genes, revealing Macrococcus as an important source for mobilization of antibiotic resistance genes within the family of Staphylococcaceae.

Prevalence and Molecular Characterization of Methicillin-Resistant Staphylococci (MRS) and Mammaliicocci (MRM) in Dromedary Camels from Algeria: First Detection of SCCmec-mecC Hybrid in Methicillin-Resistant Mammaliicoccus lentus

“…However, these MRNaS/MRM can be carriers of antimicrobial resistance genes, and potentially able to act as donors of genes for other staphylococci species including S. aureus [ 19 , 21 ]. Resistance to β-lactams antibiotics in Mammaliicoccus and Staphylococcus is mediated by the production of either an alternative penicillin-binding protein with low affinity for β-lactams or a β-lactamase [ 22 ]. The β-lactamase, which is encoded by a blaZ gene, hydrolyses only penicillin-rings, hence conferring narrow-spectrum β-lactam resistance [ 23 ].…”

“…The mecA and mecC genes can be acquired by horizontal gene transfer through staphylococcal cassette chromosome mec (SCC mec ) elements in Staphylococcus and Mammaliicoccus . The mecB and mecD genes have been found in Macrococcus on SCC mec elements, as well as on unrelated mecD -carrying Macrococcus resistance islands (McRI mecD ) and large mecB -carrying plasmids [ 22 ], and only a single case of a plasmid borne mecB -positive staphylococci ( S. aureus ) has been reported [ 25 ]. Currently, 15 SCC mec types have been described in MRSA [ 26 ].…”

Genus-Wide Genomic Characterization ofMacrococcus: Insights into Evolution, Population Structure, and Functional Potential

“…(MacFadyen et al, 2018; Mazhar et al, 2018; Ramos et al, 2021). In this context, methicillin-resistant Macrococcus strains become particularly concerning: not only can they potentially serve as opportunistic human and veterinary pathogens, but they can potentially transfer mobilizable AMR genes to other organisms, including taxa with a higher virulence potential (e.g., pathogenic Staphylococcus aureus ) (MacFadyen et al, 2018; Mazhar et al, 2018; Ramos et al, 2021; Schwendener and Perreten, 2022).…”

“…Several studies have employed genomic approaches to gain insight into the evolution and population structure of Macrococcus ; however, these studies relied on a limited number of genomes (Maslanova et al, 2018; Schwendener and Perreten, 2022) and/or focused on specific taxa within the genus (e.g., M. caseolyticus ) (MacFadyen et al, 2018; Zhang et al, 2022). Furthermore, very few studies—genomic or otherwise—describing Macrococcus spp.…”

Antimicrobial Resistance and Molecular Epidemiology of Staphylococcus aureus from Hunters and Hunting Dogs

“…Despite a downward trend in the prevalence of MRSA in the EU, 25% of European countries continue to have a rate of invasive isolates above 25% [ 6 , 7 ]. Methicillin-resistance is driven by the acquisition of the mec genes ( mec A, mec B or mec C) which encodes the penicillin-binding protein 2a (PBP2a) with a low affinity for β-lactam antibiotics [ 8 , 9 ]. Healthcare-associated (HA) and community-associated (CA)-MRSA strains have emerged and spread widely [ 10 ].…”