Abstract

Haemophilus species are important pathogens associated with respiratory infections, and their rising antibiotic resistance poses a serious treatment challenge. This study investigated the prevalence and antibiotic susceptibility patterns of Haemophilus species isolated from clinical samples obtained from patients with renal complications, respiratory infections, and underlying medical conditions at Rivers State University Teaching Hospital, Port Harcourt. A total of 128 clinical samples were collected across three age groups (0–18 years, 19–45 years, and ≥46 years), including blood (n = 20), sputum (n = 70), and nasopharyngeal swabs (n = 38). Samples were inoculated directly onto prepared agar plates using the swab technique and processed using standard microbiological, virulence, and molecular methods. Thirty-four bacterial isolates were recovered, of which sixteen were confirmed as Haemophilus species, giving an overall prevalence of 12.5%. Male patients accounted for ten positive cases, while females had six. Antibiotic susceptibility testing revealed resistance to ciprofloxacin (50%), cefotaxime (44%), and gentamicin (25%), while higher susceptibility was observed with Augmentin (81%), amoxicillin (75%), and sparfloxacin (69%). Haemolytic activity results showed that 68.8% of isolates were beta-haemolytic, 25% were alpha-haemolytic, and 6.25% were gamma-haemolytic. Additionally, 93.8% exhibited capsule formation. Molecular identification of five multidrug-resistant isolates showed 100% similarity with Haemophilus influenzae strains H1375, H54, and Rd KW20, Haemophilus haemolyticus CIP 103290, and Streptococcus pneumoniae strain K31. Gene profiling revealed the presence of the gyrA gene in all isolates and the blaTEM-1 β-lactamase gene in H54 and Rd KW20. The detection of multidrug-resistant H. influenzae highlights the urgent need for continuous local antimicrobial surveillance.