Tags

Type your tag names separated by a space and hit enter

Polymorphism in ftsI gene and {beta}-lactam susceptibility in Portuguese Haemophilus influenzae strains: clonal dissemination of beta-lactamase-positive isolates with decreased susceptibility to amoxicillin/clavulanic acid.
J Antimicrob Chemother 2011; 66(4):788-96JA

Abstract

OBJECTIVES

The aim of this study was to characterize ampicillin resistance mechanisms in clinical isolates of Haemophilus influenzae from Portugal. Association between specific patterns of amino acid substitutions in penicillin-binding protein 3 (PBP3) (with or without β-lactamase production) and β-lactam susceptibility as well as genetic relatedness among isolates were investigated.

METHODS

Two-hundred and forty non-consecutive H. influenzae isolates chosen according to their different ampicillin MICs [101 β-lactamase-non-producing ampicillin-resistant (BLNAR) isolates, 80 β-lactamase-producing ampicillin-resistant (BLPAR) isolates and 59 β-lactamase-non-producing ampicillin-susceptible (BLNAS) isolates] were analysed. The β-lactamase-encoding bla(TEM-1) gene was detected by PCR. The ftsI gene encoding PBP3 was sequenced. Genetic relatedness among isolates was examined by PFGE.

RESULTS

Of the 240 H. influenzae isolates, 141 had mutations in the transpeptidase domain of the ftsI gene, including most BLNAR strains (94/101, 93.1%) and a high percentage of BLPAR strains (47/80, 58.8%). As previously reported, the latter have been described as β-lactamase-positive amoxicillin/clavulanic acid resistant (BLPACR). The most common amino acid substitutions were identified near the KTG motif: N526K (136/141, 96.5%), V547I (124/141, 87.9%) and N569S (121/141, 85.8%). The 141 strains were divided into 31 ftsI mutation patterns and included six groups (I, IIa, IIb, IIc, IId and III-like). BLNAR strains were genetically diverse but close genetic relationships were demonstrated among BLPACR strains.

CONCLUSIONS

This study shows that the non-enzymatic mechanism of resistance to β-lactams is widespread among H. influenzae isolates in Portugal. Clonal dissemination of BLPACR strains showing high resistance to ampicillin and reduced susceptibility to amoxicillin/clavulanic acid was documented.

Authors+Show Affiliations

National Reference Laboratory for Bacterial Respiratory Infections, Department of Infectious Disease, National Institute of Health Dr. Ricardo Jorge, Av. Padre Cruz, 1649-016 Lisbon, Portugal.No affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

21393206

Citation

Barbosa, Ana Raquel, et al. "Polymorphism in ftsI Gene and {beta}-lactam Susceptibility in Portuguese Haemophilus Influenzae Strains: Clonal Dissemination of Beta-lactamase-positive Isolates With Decreased Susceptibility to Amoxicillin/clavulanic Acid." The Journal of Antimicrobial Chemotherapy, vol. 66, no. 4, 2011, pp. 788-96.
Barbosa AR, Giufrè M, Cerquetti M, et al. Polymorphism in ftsI gene and {beta}-lactam susceptibility in Portuguese Haemophilus influenzae strains: clonal dissemination of beta-lactamase-positive isolates with decreased susceptibility to amoxicillin/clavulanic acid. J Antimicrob Chemother. 2011;66(4):788-96.
Barbosa, A. R., Giufrè, M., Cerquetti, M., & Bajanca-Lavado, M. P. (2011). Polymorphism in ftsI gene and {beta}-lactam susceptibility in Portuguese Haemophilus influenzae strains: clonal dissemination of beta-lactamase-positive isolates with decreased susceptibility to amoxicillin/clavulanic acid. The Journal of Antimicrobial Chemotherapy, 66(4), pp. 788-96. doi:10.1093/jac/dkq533.
Barbosa AR, et al. Polymorphism in ftsI Gene and {beta}-lactam Susceptibility in Portuguese Haemophilus Influenzae Strains: Clonal Dissemination of Beta-lactamase-positive Isolates With Decreased Susceptibility to Amoxicillin/clavulanic Acid. J Antimicrob Chemother. 2011;66(4):788-96. PubMed PMID: 21393206.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Polymorphism in ftsI gene and {beta}-lactam susceptibility in Portuguese Haemophilus influenzae strains: clonal dissemination of beta-lactamase-positive isolates with decreased susceptibility to amoxicillin/clavulanic acid. AU - Barbosa,Ana Raquel, AU - Giufrè,Maria, AU - Cerquetti,Marina, AU - Bajanca-Lavado,Maria Paula, Y1 - 2011/01/25/ PY - 2011/3/12/entrez PY - 2011/3/12/pubmed PY - 2011/7/16/medline SP - 788 EP - 96 JF - The Journal of antimicrobial chemotherapy JO - J. Antimicrob. Chemother. VL - 66 IS - 4 N2 - OBJECTIVES: The aim of this study was to characterize ampicillin resistance mechanisms in clinical isolates of Haemophilus influenzae from Portugal. Association between specific patterns of amino acid substitutions in penicillin-binding protein 3 (PBP3) (with or without β-lactamase production) and β-lactam susceptibility as well as genetic relatedness among isolates were investigated. METHODS: Two-hundred and forty non-consecutive H. influenzae isolates chosen according to their different ampicillin MICs [101 β-lactamase-non-producing ampicillin-resistant (BLNAR) isolates, 80 β-lactamase-producing ampicillin-resistant (BLPAR) isolates and 59 β-lactamase-non-producing ampicillin-susceptible (BLNAS) isolates] were analysed. The β-lactamase-encoding bla(TEM-1) gene was detected by PCR. The ftsI gene encoding PBP3 was sequenced. Genetic relatedness among isolates was examined by PFGE. RESULTS: Of the 240 H. influenzae isolates, 141 had mutations in the transpeptidase domain of the ftsI gene, including most BLNAR strains (94/101, 93.1%) and a high percentage of BLPAR strains (47/80, 58.8%). As previously reported, the latter have been described as β-lactamase-positive amoxicillin/clavulanic acid resistant (BLPACR). The most common amino acid substitutions were identified near the KTG motif: N526K (136/141, 96.5%), V547I (124/141, 87.9%) and N569S (121/141, 85.8%). The 141 strains were divided into 31 ftsI mutation patterns and included six groups (I, IIa, IIb, IIc, IId and III-like). BLNAR strains were genetically diverse but close genetic relationships were demonstrated among BLPACR strains. CONCLUSIONS: This study shows that the non-enzymatic mechanism of resistance to β-lactams is widespread among H. influenzae isolates in Portugal. Clonal dissemination of BLPACR strains showing high resistance to ampicillin and reduced susceptibility to amoxicillin/clavulanic acid was documented. SN - 1460-2091 UR - https://www.unboundmedicine.com/medline/citation/21393206/Polymorphism_in_ftsI_gene_and_{beta}_lactam_susceptibility_in_Portuguese_Haemophilus_influenzae_strains:_clonal_dissemination_of_beta_lactamase_positive_isolates_with_decreased_susceptibility_to_amoxicillin/clavulanic_acid_ L2 - https://academic.oup.com/jac/article-lookup/doi/10.1093/jac/dkq533 DB - PRIME DP - Unbound Medicine ER -