The Epidemiology of Invasive Haemophilus influenzae Non-Serotype B Disease in Ontario, Canada from 2004 to 2013

• Published in: PloS one Vol. 10; no. 11; p. e0142179
• Main Authors: Desai, Shalini, Jamieson, Frances B, Patel, Samir N, Seo, Chi Yon, Dang, Vica, Fediurek, Jill, Navaranjan, Debeka, Deeks, Shelley L
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 16.11.2015; Public Library of Science (PLoS)
• Subjects: Adolescent; Adult; Aged; Aged, 80 and over; Ampicillin; Ampicillin - therapeutic use; Antibacterial agents; Antibiotic resistance; Antibiotics; Antimicrobial agents; Antimicrobial resistance; Care and treatment; Child; Child, Preschool; Children; Clarithromycin; Clarithromycin - therapeutic use; Data processing; Development and progression; Disease; Dosage and administration; Drug Resistance, Bacterial; Epidemiology; Female; Haemophilus Infections - epidemiology; Haemophilus Infections - microbiology; Haemophilus influenzae; Haemophilus influenzae type b; Haemophilus Vaccines - immunology; Hemophilus infections; Humans; Immunization; Incidence; Infant; Infant, Newborn; Infections; Information systems; Inhibitory Concentration 50; Laboratories; Male; Meningitis; Middle Aged; Minority & ethnic groups; Native North Americans; Ontario - epidemiology; Patient outcomes; Poisson density functions; Poisson Distribution; Population; Prevention; Public health; Regression analysis; Sepsis; Serogroup; Serotypes; Serotyping; Statistical analysis; Trends; Vaccines; Young Adult; Ontario; Canada; Ontario Canada; Sweden; Europe
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0142179

Since the widespread use of Haemophilus influenzae (Hi) type b (Hib) vaccines among children aged <5 years, an increase in invasive non-Hib disease incidence has been reported internationally. We sought to describe the epidemiology of invasive non-Hib disease in Ontario, Canada (population ~13.5 million). Confirmed invasive non-Hib cases (non-typeable [NTHi] and serotypes a, c, d, e, and f) were obtained from the provincial laboratory data system from 2004-2013. Data were deterministically linked to the provincial reportable disease system to provide further case information. Antibiotic resistance data were analysed separately from 2010-2014. Descriptive analyses included incidence rates, age group, serotype, site of specimen collection and resistance patterns; ethnicity data were not available. Temporal trends were evaluated by Poisson regression and p-values <0.05 were considered significant. A total of 1307 cases of invasive non-Hib disease were included, increasing from 0.67 cases to 1.60 cases /100,000 from 2004 to 2013. Significant increases in the incidence of NTHi (0.50 to 1.28 cases/100 000 population), Hia (0.02 to 0.08 cases/100, 000) and Hif (0.13 to 0.18 cases/100, 000 population) were seen. Among persons aged 40-64 years, 3 Hi strains significantly increased over time; NTHi (0.22 to 0.99 cases/100, 000), Hia (0.00 to 0.06 cases/100, 000) and Hif (0.05 to 0.21 cases/100, 000). Among persons aged 65-84 years, there was a significant increase of NTHi (1.62 to 3.14 cases/100, 000) and Hia (0.00 to 0.34 cases/100, 000). Among persons aged 85+ years, only NTHi significantly increased from 4.89 to 10.28 cases/100, 000). Antimicrobial resistance (AMR) to ampicillin and clarithromycin was seen in greater than 25% of isolates but AMR did not increase over the duration of this study. The incidence of invasive non-Hib disease has increased over time; NTHi, Hif and Hia are emerging pathogens, and should be monitored.