This work is dedicated to my dearest and devoted friend, Sandra Rodin, for being my constant inspiration and support And to my dear Mom, whose encouragement and belief in me made this possible In loving memory of my morfar, Sven Henriksson, who I can only imagine is crying tears of joy in heaven right now. Jag älskar dig, Poppop! “Vi kan inte göra stora saker, bara små saker med stor kärlek” Mother Teresa “Being a graduate student is like becoming all of the Seven Dwarves. In the beginning you’re Dopey and Bashful. In the middle you are usually Sneezy, Sleepy, and Grumpy. But at the end, they call you Doc, and then you’re Happy.” Unknown LIST OF PAPERS This thesis is based on the following papers, which are referred to in the text by their Roman numerals: I. McGill, S., R. Regnery, and K. Karem. (1998) Characterization of human immunoglobulin (Ig) isotype and IgG subclass response to Bartonella henselae infection. Infect Immun, 66(12):5915-20. II. Holmberg, M., S. McGill, C. Ehrenborg, L. Wesslén, E. Hjelm, J. Darelid, L. Blad, L. Engstrand, R. Regnery, and G. Friman. (1999) Evaluation of human seroreactivity to Bartonella species in Sweden. J Clin Microbiol, 37(5):1381-4. III. McGill, S., L. Wesslén, E. Hjelm, M. Holmberg, C. Rolf, and G. Friman. (2001) Serological and epidemiological analysis of the prevalence of Bartonella spp. antibodies in Swedish elite orienteers 1992-93. Scand J Infect Dis, 33(6):423-8. IV. Hjelm, E., S. McGill, and G. Blomqvist. (2002) Prevalence of antibodies to Bartonella henselae, B. elizabethae, and B. quintana in Swedish domestic cats. Scand J Infect Dis, 34(3):192-6. V. McGill, S., J. Rajs, E. Hjelm, O. Lindquist, and G. Friman. (2003) A study on forensic samples of Bartonella spp. antibodies in Swedish intravenous heroin addicts. APMIS, 111:507-13. VI. McGill, S., L. Wesslén, E. Hjelm, M. Holmberg, M. Auvinen, K. Berggren, B. Grandin-Jarl, U. Johnson, S. Wikström, and G. Friman. (2005) Bartonella spp. seroprevalence in healthy Swedish blood donors. Scand J Infect Dis, 37(10):723-30. Reprints were made with permission from the publishers. CONTENTS INTRODUCTION ........................................................................................11 Historical overview ..................................................................................11 Bacteriology and epidemiology................................................................13 Bartonella spp. genomes ..........................................................................15 Bartonellae and their spectrum of clinical manifestations.......................16 B. bacilliformis ....................................................................................17 B. quintana...........................................................................................17 B. henselae...........................................................................................18 CSD.................................................................................................18 B. elizabethae.......................................................................................20 Other Bartonellae ................................................................................20 Laboratory diagnosis of Bartonella infection ..........................................22 Serological cross-reactivity ......................................................................24 Bartonella seroprevalence studies............................................................27 Seroprevalence in various human subpopulations...............................27 Seroprevalence in cats .........................................................................29 Bartonella in Sweden ...............................................................................31 Swedish orienteering investigation......................................................31 Human and animal studies in Sweden .................................................32 AIMS OF THE PRESENT STUDY .............................................................36 MATERIALS AND METHODS..................................................................37 Cultivation of Bartonella spp. antigens (I-VI) .........................................37 Study samples (I-VI) ................................................................................37 Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS- PAGE) (I) .................................................................................................38 Western blot analysis (I) ..........................................................................38 IFA (II-VI)................................................................................................39 PCR and DNA sequencing (II).................................................................39 Post-mortem and forensic analysis (II, V)................................................40 Collection of epidemiological data (III,VI)..............................................40 Statistical analysis (III-VI) .......................................................................40 RESULTS AND DISCUSSION...................................................................42 Analysis of human humoral immune response to Bartonella spp. infection by Western blot (I) ....................................................................42 Total immunoglobulin (Ig)G reactivity to B. henselae whole-cell and Vero cell co-cultivated antigen (I) .......................................................42 IgG-specific fragment and subclass reactivity to B. henselae antigen.44 Immunoglobulin isotype reactivity to B. henselae antigen..................45 Seroreactivity to Bartonella spp. among various cohorts of the Swedish human and animal population (II-VI) ......................................................46 Blood donors (II, III, VI) .....................................................................46 Patients (II) ..........................................................................................48 Elite orienteers (III) .............................................................................49 Intravenous drug users (IVDU) (V).....................................................51 Cats (IV) ..............................................................................................53 Demographic and epidemiologic findings (III, IV, V, VI).........................55 Future prospects and the significance of high B. elizabethae seroprevalence..........................................................................................56 GENERAL CONCLUSIONS.......................................................................59 ACKNOWLEDGEMENTS..........................................................................60 REFERENCES .............................................................................................62 ABBREVIATIONS ARVC Arrhythmogenic right ventricular cardiomyopathy BA Bacillary angiomatosis Bc Bartonella clarridgeiae Be Bartonella elizabethae Bg Bartonella grahamii Bh, Bh(H-1) Bartonella henselae (Houston-1) Bh(M) Bartonella henselae (Marseille) BMI Body mass index Bq Bartonella quintana Bv Bartonella vinsonii cANCA Anti-neutrophil cytoplasmic antibody test CDC Centers for Disease Control and Prevention CI Confidence interval CSD Cat scratch disease CT Computerized tomography; Cutoff titer DNA Deoxyribonucleic acid EIA Enzyme immunoassay (synonymous with ELISA) ELISA Enzyme-linked immunosorbent assay (synonymous with EIA) FITC Fluorescein isothiocynate GEI Genomic island GMT Geometric mean titer HEPES 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid HIV Human immunodeficiency virus IFA Indirect fluorescent-antibody/immunofluorescence assay Ig Immunoglobulin IVD Intravenous drug kDa Kilodalton M Multivariate logistic regression OR Odds ratio PBS/T Phosphate-buffered saline/ plus Tween-20 POS Parinaud’s oculoglandular syndrome PCR Polymerase chain reaction SDS-PAGE Sodium dodecyl sulfate-polyacrylamide-gel electrophoresis SUCD Sudden unexpected cardiac death Spp/Sp Species, plural/ Species, singular U Univariate logistic regression INTRODUCTION Historical overview The genus Bartonella has undoubtedly achieved a level of undisputed clinical importance as both an emerging and re-emerging human pathogen in a relatively short expanse of time. Prior to 1993, the genus Bartonella was composed of a single species, B. bacilliformis, the causative agent of Oroya fever, or Carrion’s disease, first described in South America in the late 1800’s. Subsequent to its isolation and identification in 1909, B. bacilliformis remained the sole member of the genus Bartonella for nearly a century. As a consequence of various factors, highlighted by improved detection and diagnostic capabilities, as well as reclassification of several bacterial genera on the basis of phylogenetic relatedness using 16S rRNA gene sequences, the genus has undergone a substantial expansion. In 1993, the genus was initially broadened through unification with the genus Rochalimaea (39), which was comprised of the species R. quintana (formerly Rickettsia quintana), R. henselae, R. vinsonii, and R. elizabethae, and again in 1995 through a subsequent unification with the genus Grahamella (29), which contained the species G. grahamii, G. taylorii, G. talpae, and G. doshiae. Following these amalgamations, all of the aforementioned species were reclassified as Bartonella and the genus was removed from the order Rickettsiales (29). The genus Bartonella has continued to grow in recent years with the isolation