What bacteria are resistant to macrolides?
Macrolides, Lincosamides, and Their Spectrum of Activity Gram-negative bacilli are generally resistant, with some important exceptions (i.e., Bordetella pertussis, Campylobacter, Chlamydia, Helicobacter, and Legionella species).
What is macrolide resistance?
Macrolides are bacteriostatic antibiotics and inhibit protein synthesis by binding to the 50S ribosomal subunit. The widespread use of macrolides is associated with increased macrolide resistance in S. pneumoniae, and the treatment of pneumococcal infections with macrolides may be associated with clinical failures.
How do bacteria become resistant to erythromycin?
Erythromycin resistance among streptococci can be due to target-site modification by an rRNA-methylating enzyme or by an efflux system. Target-site modification can be expressed either in a constitutive or inducible manner, resulting in co-resistance to macrolide, lincosamide and streptogramin B antibiotics (MLSB).
What bacteria is resistant to azithromycin?
Since the late 1990s, macrolide-resistant Streptococcus pneumoniae and Staphylococcus aureus infections have been increasing in Australia. Over 10% of S. pneumoniae infections and over 15% of S. aureus infections have been reported to be resistant to azithromycin.
What are macrolide antibiotics used for?
Macrolides are a class of antibiotic that includes erythromycin, roxithromycin, azithromycin and clarithromycin. They are useful in treating respiratory, skin, soft tissue, sexually transmitted, H. pylori and atypical mycobacterial infections.
What kind of bacteria does erythromycin treat?
Erythromycin is active against most gram-positive bacteria; some gram-negative bacteria, including Neisseria, Bordetella, Bruceila, Campylobacter, and Legionella; and Treponema, Chlamydia, and Mycoplasma. The emergence of resistance to erythromycin is closely associated with its use and is often plasmid mediated.
Can azithromycin cause antibiotic resistance?
For these reasons, azithromycin became the most commonly prescribed antibiotic in the United States in 2011. However, resistance is increasingly of concern, with recent studies showing high rates of azithromycin resistance, particularly in pneumococci.
Is E coli resistant to azithromycin?
Despite azithromycin being used in some countries to treat infections caused by Gram-negative pathogens, no resistance breakpoint for Escherichia coli exists.
How are the mutations of macrolide resistance genes determined?
Macrolide susceptibility, mutations and carriage of the macrolide resistance genes erm (A), erm (B), erm (C), erm (F) and mef (A) were determined using PCR assays and sequencing or hybridization of the PCR products. H. influenzae isolates were used as donors in conjugation studies with H. influenzae and Enterococcus faecalis recipients.
How are microorganisms resistance to macrolides and lincosamides?
A wide range of microorganisms that are targets for macrolides and lincosamides, including gram-positive species, spirochetes, and anaerobes, express Erm methylases. Nearly 40 erm genes have been reported so far [ 3 ]. In pathogenic bacteria, these determinants are mostly borne by plasmids and transposons that are self-transferable.
What are the other aspects of macrolide resistance?
Other aspects of macrolide resistance are the multiplicity of resistance mechanisms and the diversity in phenotypic expression of several of these mechanisms. These aspects render it difficult to correctly interpret the in vitro susceptibility tests and, ultimately, the correct therapeutic use of this class of antibiotics.
How are erm genes resistant to macrolides and lincosamides?
The presence of an inducer leads to rearrangements of mRNA, which allow ribosomes to translate the methylase coding sequence. The strains harboring an inducible erm gene are resistant to the inducers but remain susceptible to noninducer macrolides and lincosamides.