Antimicrobial resistance among agents of community-associated lower respiratory tract infection: UK and Ireland trends from 1999/2000 to 2018/2019

Reynolds, Rosy, Felmingham, David, Mushtaq, Shazad, Horner, Carolyne, Chaudhry, Aiysha, Adkin, Rachael, Allen, Michael, Longshaw, Christopher, Parcell, Benjamin J. and Livermore, David M. (2025) Antimicrobial resistance among agents of community-associated lower respiratory tract infection: UK and Ireland trends from 1999/2000 to 2018/2019. Journal of Antimicrobial Chemotherapy. ISSN 0305-7453 (In Press)

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Abstract

Objectives. The BSAC Respiratory Surveillance Programme examined resistance trends among Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis from patients with community-acquired lower respiratory tract infection (CA-LRTI).   Methods. Quotas of isolates were sought per collecting site from 1999/00 to 2018/19; an annual October start date captured winter infection peaks within single years. MIC testing was by BSAC agar dilution, β-lactamase detection with nitrocefin, pneumococcal serotyping by classical methods or WGS.   Results. Resistances were uncommon, except that β-lactamases occurred in c. 20% H. influenzae from 2012/13 following earlier rises, and in >90% of M. catarrhalis throughout. Only 12/10881 S. pneumoniae were fully resistant to penicillin; co-amoxiclav inhibited 97.8% of 13526 H. influenzae and >99.9% of 6309 M. catarrhalis isolates. Cefotaxime inhibited >99% of all isolates at breakpoint, as did other fluoroquinolones in the fewer years tested. Tetracycline inhibited >98% of H. influenzae and M. catarrhalis, also 85% of S. pneumoniae. Significant shifts were (i) fluctuating resistances to tetracyclines, macrolides and penicillin in pneumococci, reflecting serotype replacements; (ii) expansion, from 2012/13, in the proportion of H. influenzae with β-lactamase-independent amoxicillin/co-amoxiclav resistance and (iii) increasing high-level amoxicillin resistance (MIC >64 mg/L) in β-lactamase-positive H. influenzae. MIC differentials were seen for cephalosporins between β-lactamase-positive and -negative M. catarrhalis, greatest (512-fold) for ceftaroline.   Conclusion. CA-LRTI remains eminently treatable, yet shifts are occurring in the serotypes of S. pneumoniae most associated with resistance and in the nature of amoxicillin resistance in H. influenzae. β-Lactamase-related cephalosporin MIC differentials for M. catarrhalis are striking; their clinical significance remains uncertain.

Item Type:	Article
Faculty \ School:	Faculty of Medicine and Health Sciences > Norwich Medical School
UEA Research Groups:	Faculty of Medicine and Health Sciences > Research Groups > Epidemiology and Public Health
Depositing User:	LivePure Connector
Date Deposited:	10 Oct 2025 13:32
Last Modified:	10 Oct 2025 13:32
URI:	https://ueaeprints.uea.ac.uk/id/eprint/100690
DOI:	issn:0305-7453

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