Silvia García-Cobos1, Miriam Moscoso2, Félix Pumarola3, Margarita Arroyo4, Noelia Lara4, María Pérez-Vázquez4, Belén Aracil4, Jesús Oteo4, Ernesto García2, José Campos5. 1. Antibiotic and Haemophilus Laboratory, Bacteriology Service, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain Department of Medical Microbiology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands. 2. Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Madrid, Spain. 3. Servicio de Otorrinolaringología, Hospital Universitario Vall d'Hebron, Barcelona, Spain. 4. Antibiotic and Haemophilus Laboratory, Bacteriology Service, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain. 5. Antibiotic and Haemophilus Laboratory, Bacteriology Service, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain Consejo Superior de Investigaciones Científicas, Madrid, Spain jcampos@isciii.es.
Abstract
OBJECTIVES: Non-typeable Haemophilus influenzae are a major cause of acute otitis media (AOM), including chronic and recurrent otitis in young children. The objective of this study was to determine whether non-typeable H. influenzae isolates causing these infections produce biofilms and carry resistance mechanisms to β-lactams. METHODS: A collection of 48 H. influenzae isolates was obtained by tympanocentesis or from otorrhoea samples from individual patients <3 years of age and diagnosed with recurrent or treatment failure AOM. Each isolate was surveyed for the presence of blaTEM genes, amino acid substitutions in the transpeptidase domain of penicillin-binding protein 3 (PBP3) and biofilm formation in microtitre plates. RESULTS: In 43 of the 48 isolates (89.6%), at least one of the three tested conditions was identified: biofilm formation (83.3%) and resistance mechanisms to β-lactams (33.3%), modifications in the transpeptidase domain of PBP3 being the most prevalent (22.9%), followed by β-lactamase production (10.4%). Additionally, 13 (27.1%) isolates had two or more of these three traits. In relation to biofilm formation, those isolates with an amoxicillin MIC ≤ 0.5 mg/L had higher optical density values than isolates with an amoxicillin MIC ≥ 1 mg/L (Mann-Whitney U-test, P=0.048). CONCLUSIONS: These findings suggest that the successful treatment of non-typeable H. influenzae causing chronic and recurrent AOM in young children may be compromised by the high biofilm-forming capacity of the isolates and the presence of β-lactam resistance mechanisms, particularly PBP3 mutations.
OBJECTIVES: Non-typeable Haemophilus influenzae are a major cause of acute otitis media (AOM), including chronic and recurrent otitis in young children. The objective of this study was to determine whether non-typeable H. influenzae isolates causing these infections produce biofilms and carry resistance mechanisms to β-lactams. METHODS: A collection of 48 H. influenzae isolates was obtained by tympanocentesis or from otorrhoea samples from individual patients <3 years of age and diagnosed with recurrent or treatment failure AOM. Each isolate was surveyed for the presence of blaTEM genes, amino acid substitutions in the transpeptidase domain of penicillin-binding protein 3 (PBP3) and biofilm formation in microtitre plates. RESULTS: In 43 of the 48 isolates (89.6%), at least one of the three tested conditions was identified: biofilm formation (83.3%) and resistance mechanisms to β-lactams (33.3%), modifications in the transpeptidase domain of PBP3 being the most prevalent (22.9%), followed by β-lactamase production (10.4%). Additionally, 13 (27.1%) isolates had two or more of these three traits. In relation to biofilm formation, those isolates with an amoxicillin MIC ≤ 0.5 mg/L had higher optical density values than isolates with an amoxicillin MIC ≥ 1 mg/L (Mann-Whitney U-test, P=0.048). CONCLUSIONS: These findings suggest that the successful treatment of non-typeable H. influenzae causing chronic and recurrent AOM in young children may be compromised by the high biofilm-forming capacity of the isolates and the presence of β-lactam resistance mechanisms, particularly PBP3 mutations.
Authors: Rahul Mittal; Christopher V Lisi; Robert Gerring; Jeenu Mittal; Kalai Mathee; Giri Narasimhan; Rajeev K Azad; Qi Yao; M'hamed Grati; Denise Yan; Adrien A Eshraghi; Simon I Angeli; Fred F Telischi; Xue-Zhong Liu Journal: J Med Microbiol Date: 2015-08-05 Impact factor: 2.472
Authors: Judith M Martin; Alejandro Hoberman; Nader Shaikh; Timothy Shope; S Onika Bhatnagar; Stan L Block; Mary Ann Haralam; Marcia Kurs-Lasky; Michael Green Journal: Open Forum Infect Dis Date: 2018-02-17 Impact factor: 3.835