Antibiotic Susceptibility and Molecular Typing of Invasive Haemophilus influenzae Isolates, with Emergence of Ciprofloxacin Resistance, 2017-2021, Italy

Maria Giufrè; Rita Cardines; Manuela Marra; Maria Carollo; Marina Cerquetti; Paola Stefanelli

doi:10.3390/microorganisms11020315

Antibiotic Susceptibility and Molecular Typing of Invasive Haemophilus influenzae Isolates, with Emergence of Ciprofloxacin Resistance, 2017-2021, Italy

Microorganisms. 2023 Jan 26;11(2):315. doi: 10.3390/microorganisms11020315.

Authors

Maria Giufrè¹, Rita Cardines¹, Manuela Marra², Maria Carollo², Marina Cerquetti¹, Paola Stefanelli¹

Affiliations

¹ Department of Infectious Diseases, Istituto Superiore di Sanità, 00161 Rome, Italy.
² Core Facilities Technical-Scientific Service (FAST), Istituto Superiore di Sanità, 00161 Rome, Italy.

Abstract

Haemophilus influenzae invasive disease is a severe infection that needs rapid antibiotic therapy. The aim of the study was to perform and evaluate the serotype distribution, antibiotic susceptibility and molecular characteristics of 392 H. influenzae invasive isolates collected during 2017-2021 in Italy. The majority of isolates were NTHi (305/392, 77.8%), followed by Hib (49/392, 12.5%). Ampicillin resistance was frequently detected (85/392, 21.7%): 12.2% were β-lactamase producers (all bla_TEM except one bla_ROB), 9.4% were β-lactamase-negative ampicillin-resistant (BLNAR), with mutations in the ftsI gene. Six isolates were resistant to ciprofloxacin, with substitutions in GyrA and ParC. An MLST analysis revealed the occurrence of international resistant clones, such as ST103 and ST14, highlighting the importance of molecular surveillance.

Keywords: Haemophilus influenzae; MLST; antibiotic resistance; quinolone resistance; surveillance; whole genome sequencing.

Grants and funding

This research received no external funding.