Novel mechanisms of resistance to β-lactam antibiotics in Haemophilus parainfluenzae: β-lactamase-negative ampicillin resistance and inhibitor-resistant TEM β-lactamases
| العنوان: | Novel mechanisms of resistance to β-lactam antibiotics in Haemophilus parainfluenzae: β-lactamase-negative ampicillin resistance and inhibitor-resistant TEM β-lactamases |
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| المؤلفون: | José Campos, Noelia Lara, Belén Aracil, Emilia Cercenado, Silvia García-Cobos, Jesús Oteo, Beatriz Orden, María Pérez-Vázquez, Margarita Arroyo |
| المصدر: | Journal of Antimicrobial Chemotherapy, 68(5), 1054-1059. Oxford University Press |
| سنة النشر: | 2013 |
| مصطلحات موضوعية: | Microbiology (medical), DNA, Bacterial, Cefotaxime, Haemophilus Infections, Genotype, Penicillin-Binding Proteins/genetics, Haemophilus Infections/microbiology, beta-Lactamases/genetics, Microbial Sensitivity Tests, Biology, medicine.disease_cause, Polymerase Chain Reaction, beta-Lactamases, Haemophilus influenzae, Microbiology, Anti-Bacterial Agents/pharmacology, Amp resistance, Aminopenicillin, Haemophilus parainfluenzae, Ampicillin, Clavulanic acid, DNA, Bacterial/chemistry, medicine, Humans, Penicillin-Binding Proteins, Bacterial/chemistry, Pharmacology (medical), Ampicillin/pharmacology, Pharmacology, Haemophilus influenzae/drug effects, DNA, Sequence Analysis, DNA, Amoxicillin, biology.organism_classification, Anti-Bacterial Agents, Infectious Diseases, Sequence Analysis, Ampicillin Resistance, medicine.drug |
| الوصف: | OBJECTIVES: To determine the mechanisms of resistance to β-lactam antibiotics in clinical isolates of Haemophilus parainfluenzae.METHODS: Twenty clinical isolates of H. parainfluenzae with decreased susceptibility to aminopenicillins were examined and compared with a control group of 20 fully susceptible isolates. In this collection, the presence of amino acid substitutions in the transpeptidase domain of penicillin-binding protein 3 (PBP3), β-lactamase production and the surrounding genetic regions of blaTEM genes in selected isolates were analysed.RESULTS: Of the 20 non-susceptible isolates, 8 produced TEM β-lactamase (gBLPAR), 7 had mutations in the transpeptidase domain of the ftsI gene related to decreased susceptibility to β-lactams (gBLNAR) and 5 had both resistance mechanisms (gBLPACR). No resistance mechanisms were identified in the susceptible control group (gBLNAS). gBLNAR isolates had MIC90 values 4- to 16-fold higher than gBLNAS isolates for ampicillin, amoxicillin/clavulanic acid, cefuroxime, cefotaxime and cefixime, and the most common PBP3 mutation was Asn526Ser. The additional Ser385Thr substitution (III-like group) may confer decreased susceptibility to cefotaxime, cefixime and aztreonam, as in Haemophilus influenzae. In two β-lactamase-positive isolates without PBP3 mutations, the inhibitor-resistant TEM (IRT) β-lactamases TEM-34 and the novel TEM-182 were detected and carried by a TnA transposon of the Tn2 type; both isolates had an amoxicillin/clavulanic acid MIC of ≥8 mg/L. The TnA transposons of two β-lactamase-positive isolates (TEM-1 and TEM-182) were inserted between the tfc20 and tfc21 genes, typically associated with integrative and conjugative elements in Haemophilus spp.; the TEM-34 IRT β-lactamase was harboured in a ∼5.5 kb plasmid.CONCLUSIONS: Clinical isolates of H. parainfluenzae express a variety of aminopenicillin resistance mechanisms, either alone or in combination, including PBP3 modifications, blaTEM-1 and IRT β-lactamase production. |
| تدمد: | 1460-2091 0305-7453 |
| الوصول الحر: | https://explore.openaire.eu/search/publication?articleId=doi_dedup___::d861a2fb6e75079d208e6d4467f8eee6Test https://pubmed.ncbi.nlm.nih.gov/23335113Test |
| حقوق: | OPEN |
| رقم الانضمام: | edsair.doi.dedup.....d861a2fb6e75079d208e6d4467f8eee6 |
| قاعدة البيانات: | OpenAIRE |
| تدمد: | 14602091 03057453 |
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