Population-based laboratory surveillance of Hafnia alvei isolates in a large Canadian health region

BACKGROUND: Hospital-based series have characterized Hafnia alvei primarily as an infrequent agent of polymicrobial nosocomial infections in males with underlying illness. METHODS: We conducted population-based laboratory surveillance in the Calgary Health Region during 2000–2005 to define the incidence, demographic risk factors for acquisition, and anti-microbial susceptibilities of Hafnia alvei isolates. RESULTS: A total of 138 patients with Hafnia alvei isolates were identified (2.1/100,000/year) and two-thirds were of community onset. Older age and female gender were important risk factors for acquisition. The most common focus of isolation was urine in 112 (81%), followed by lower respiratory tract in 10 (7%), and soft tissue in 5 (4%), and the majority (94; 68%) were mono-microbial. Most isolates were resistant to ampicillin (111;80%), cephalothin (106; 77%), amoxicillin/clavulanate (98; 71%), and cefazolin (95; 69%) but none to imipenem or ciprofloxacin. CONCLUSION: Hafnia alvei was most commonly isolated as a mono-microbial etiology from the urinary tract in women from the community. This study highlights the importance of population-based studies in accurately defining the epidemiology of an infectious disease.