Characterisation of Hafnia alvei isolates from human clinical extra-intestinal specimens: haemagglutinins, serum resistance and siderophore synthesis

• Published in: Journal of medical microbiology Vol. 50; no. 3; pp. 208 - 214
• Main Authors: PODSCHUN, R, FISCHER, A, ULLMANN, U
• Format: Journal Article
• Language: English
• Published: Reading Soc General Microbiol 01.03.2001; Society for General Microbiology
• Subjects: Antibacterial agents; Antibiotics. Antiinfectious agents. Antiparasitic agents; Bacteriology; Biological and medical sciences; Blood Bactericidal Activity; Enterobacter cloacae; Epidemiology; Fundamental and applied biological sciences. Psychology; Hafnia alvei; Hafnia alvei - immunology; Hafnia alvei - metabolism; Hafnia alvei - pathogenicity; Hemagglutination Tests; Humans; Klebsiella pneumoniae; Medical sciences; Microbiology; Pharmacology. Drug treatments; Serratia marcescens; serum resistance; Siderophores - biosynthesis; Virulence; Human; Enterobacter cloacae; Digestive system; Hemagglutinin; Virulence; Gut; Mannose; Pathogenicity; Resistance; Sensitivity; Siderophore; Pathogenic; Serratia marcescens; Bacteria; Serum; Hafnia; Clinical isolate; Klebsiella pneumoniae; Enterobacteriaceae
• ISSN: 0022-2615; 1473-5644
• DOI: 10.1099/0022-1317-50-3-208

Department of Medical Microbiology and Virology, University of Kiel, Kiel, Germany Corresponding author: Dr R. Podschun (e-mail: podschun{at}medmicrobio.uni-kiel.de ). Received 26 April 2000; revised version accepted 27 July 2000. Abstract Extra-intestinal Hafnia alvei isolates are rarely considered to be pathogenic. To investigate whether such strains are able to produce virulence factors, a total of 70 clinical H. alvei isolates was compared with clinical extra-intestinal isolates of other members of the enterobacterial tribe Klebsiellae ( Klebsiella pneumoniae , Enterobacter cloacae, Serratia marcescens ). Whereas mannose-sensitive haemagglutination (MSHA) was less common in H. alvei (59%) than in K. pneumoniae (86%) and E. cloacae (89%) isolates, the incidences of mannose-resistant haemagglutination indicative of type 3 pili (MR/K-HA) and of serum resistance properties were not lower. All H. alvei strains secreted siderophores but, unlike the other enterobacterial species examined, the siderophore type was neither enterobactin nor aerobactin. Although the low pathogenicity of H. alvei isolates could not be attributed to any of the factors investigated, the mean number of factors expressed by each H. alvei isolate was significantly lower than that expressed by K. pneumoniae and E. cloacae isolates but did not differ significantly from that of S. marcescens . Based on these findings, the low pathogenicity of H. alvei appears to be due to its low frequency of expression of virulence factors as compared with clinically significant species such as K. pneumoniae and E. cloacae .