Currently, the accepted method for Q fever serodiagnosis is indirect immunofluorescent antibody assay (IFA) using the whole cell antigen. In this study, we prepared the recombinant antigen of the 27-kDa outer membrane protein (Com1) which has been shown to be recognized by Q fever patient sera. The performance of recombinant Com1 was evaluated in ELISA by IFA confirmed serum samples. Due to the low titers of IgG and IgM in Q fever patients, the standard ELISA signals were further amplified by using biotinylated anti-human IgG or IgM plus streptavidin-HRP polymer. The modified ELISA can detect 88% (29 out of 33) of Q fever patient sera collected from Marines deployed to Iraq. Less than 5% (5 out of 156) of the sera from patients with other febrile diseases reacted with the Com1. These results suggest that the modified ELISA using Com1 may have the potential to improve the detection of Q fever specific antibodies. 1. Introduction Q fever is a worldwide zoonotic disease caused by infection with Coxiella burnetii. This agent is highly infectious for humans by aerosol, where a single organism can cause the disease. Due to Q fever’s worldwide distribution and the high infectivity of C. burnetii, US military and civilian personnel deployed overseas are at high risk of being infected. Several studies [1–3] showed that Q fever poses a greater threat to US forces deployed in Iraq than previously predicted. An investigation of febrile illness outbreak among marines in Hit, Iraq, highlights the fact that Q fever is capable of causing localized outbreaks in exposed military personnel with attack rates up to 50% and perhaps higher [4]. The U.S. Army Center for Health Promotion and Preventive Medicine (USACHPPM) initiated a Q fever surveillance program in early 2007. Over 150 cases have been confirmed among U.S. military personnel deployed to Iraq since 2007 [5]. In addition, the largest known reported Q fever outbreak involved approximately 4,000 human cases and occurred from 2007 to 2010 in the Netherlands [6]. Acute Q fever illness most commonly presents as a flu-like illness, pneumonia, or hepatitis. Symptoms of Q fever are easily confused with those due to a variety of other pathogens (e.g., dengue, malaria, and leptospirosis) that may require different treatment regimens. The chronic form is infrequent (<5% of patients with acute infections), but the potentially consequent endocarditis is often fatal if left untreated [6, 7]. Therefore, early diagnosis to guide an appropriate treatment is critical for patient care. Although the presence of C burnetii DNA can be
References
[1]
A. D. Anderson, B. Smoak, E. Shuping, C. Ockenhouse, and B. Petruccelli, “Q fever and the US military,” Emerging Infectious Diseases, vol. 11, no. 8, pp. 1320–1322, 2005.
[2]
C. Leung-Shea and P. J. Danaher, “Q fever in members of the United States armed forces returning from Iraq,” Clinical Infectious Diseases, vol. 43, no. 8, pp. e77–e82, 2006.
[3]
T. D. Gleeson, C. F. Decker, M. D. Johnson, J. D. Hartzell, and J. R. Mascola, “Q Fever in US Military Returning from Iraq,” The American Journal of Medicine, vol. 120, no. 9, pp. e11–e12, 2007.
[4]
D. J. Faix, D. J. Harrison, M. S. Riddle et al., “Outbreak of Q fever among US military in Western Iraq, June-July 2005,” Clinical Infectious Diseases, vol. 46, no. 7, pp. e65–e68, 2008.
[5]
J. D. Hartzell, T. Gleeson, S. Scoville, R. F. Massung, G. Wortmann, and G. J. Martin, “Practice guidelines for the diagnosis and management of patients with Q Fever by the Armed Forces Infectious Diseases Society,” Military Medicine, vol. 177, no. 5, pp. 484–494, 2012.
[6]
Center for Disease Control and Prevention, “Diagnosis and management of Q fever,” Morbidity and Mortality Weekly Report, vol. 62, no. 3, pp. 1–23, 2013.
[7]
J.-M. Rolain, A. Boulos, M.-N. Mallet, and D. Raoult, “Correlation between ratio of serum doxycycline concentration to MIC and rapid decline of antibody levels during treatment of Q fever endocarditis,” Antimicrobial Agents and Chemotherapy, vol. 49, no. 7, pp. 2673–2676, 2005.
[8]
P.-E. Fournier and D. Raoult, “Comparison of PCR and serology assays for early diagnosis of acute Q fever,” Journal of Clinical Microbiology, vol. 41, no. 11, pp. 5094–5098, 2003.
[9]
P. M. Schneeberger, M. H. A. Hermans, E. J. van Hannen, J. J. A. Schellekens, A. C. A. P. Leenders, and P. C. Wever, “Real-time PCR with serum samples is indispensable for early diagnosis of acute Q fever,” Clinical and Vaccine Immunology, vol. 17, no. 2, pp. 286–290, 2010.
[10]
M. Turra, G. Chang, D. Whybrow, G. Higgins, and M. Qiao, “Diagnosis of acute Q fever by PCR on sera during a recent outbreak in rural South Australia,” Annals of the New York Academy of Sciences, vol. 1078, pp. 566–569, 2006.
[11]
P.-E. Fournier, T. J. Marrie, and D. Raoult, “Diagnosis of Q fever,” Journal of Clinical Microbiology, vol. 36, no. 7, pp. 1823–1834, 1998.
[12]
G. Dupuis, O. Peter, and M. Peacock, “Immunoglobulin responses in acute Q fever,” Journal of Clinical Microbiology, vol. 22, no. 4, pp. 484–487, 1985.
[13]
M. G. Peacock, R. N. Philip, J. C. Williams, and R. S. Faulkner, “Serological evaluation of Q fever in humans: enhanced phase I titers of immunoglobulins G and A are diagnostic for Q fever endocarditis,” Infection and Immunity, vol. 41, no. 3, pp. 1089–1098, 1983.
[14]
O. Peter, G. Dupuis, W. Burgdorfer, and M. Peacock, “Evaluation of the complement fixation and indirect immunofluorescence tests in the early diagnosis of primary Q fever,” European Journal of Clinical Microbiology, vol. 4, no. 4, pp. 394–396, 1985.
[15]
O. Peter, G. Dupuis, M. G. Peacock, and W. Burgdorfer, “Comparison of enzyme-linked immunosorbent assay and complement fixation and indirect fluorescent-antibody tests for detection of Coxiella burnetii antibody,” Journal of Clinical Microbiology, vol. 25, no. 6, pp. 1063–1067, 1987.
[16]
I. J. Uhaa, D. B. Fishbein, J. G. Olson, C. C. Rives, D. M. Waag, and J. C. Williams, “Evaluation of specificity of indirect enzyme-linked immunosorbent assay for diagnosis of human Q fever,” Journal of Clinical Microbiology, vol. 32, no. 6, pp. 1560–1565, 1994.
[17]
J. C. Williams, L. A. Thomas, and M. G. Peacock, “Identification of phase-specific antigenic fractions of Coxiella burnetii by enzyme-linked immunosorbent assay,” Journal of Clinical Microbiology, vol. 24, no. 6, pp. 929–934, 1986.
[18]
H. T. Dupont, X. Thirion, and D. Raoult, “Q fever serology: cutoff determination for microimmunofluorescence,” Clinical and Diagnostic Laboratory Immunology, vol. 1, no. 2, pp. 189–196, 1994.
[19]
O. Peter, G. Dupuis, D. Bee, R. Luthy, J. Nicolet, and W. Burgdorfer, “Enzyme-linked immunosorbent assay for diagnosis of chronic Q fever,” Journal of Clinical Microbiology, vol. 26, no. 10, pp. 1978–1982, 1988.
[20]
N. Schmeer, “Enzyme-linked immunosorbent assay (ELISA) for the demonstration of IgG1, IgG2 and IgM antibodies in bovine Q fever infection,” Zentralblatt für Bakteriologie, Parasitenkunde, Infektionskrankheiten und Hygiene, vol. 259, no. 1, pp. 20–34, 1985.
[21]
A. Setiyono, M. Ogawa, Y. Cai, S. Shiga, T. Kishimoto, and I. Kurane, “New criteria for immunofluorescence assay for Q fever diagnosis in Japan,” Journal of Clinical Microbiology, vol. 43, no. 11, pp. 5555–5559, 2005.
[22]
J. C. Williams and S. Stewart, “Identification of immunogenic proteins of Coxiella burnetii phase variants,” in Microbiology, L. Leive and D. Schlessinger, Eds., pp. 257–262, American Society for Microbiology, Washington, DC, USA, 9th edition, 1984.
[23]
H. To, A. Hotta, G. Q. Zhang et al., “Antigenic characteristics of polypeptides of Coxiella burnetii isolates,” Microbiology and Immunology, vol. 42, no. 2, pp. 81–85, 1998.
[24]
L. R. Hendrix, L. P. Mallavia, and J. E. Samuel, “Cloning and sequencing of Coxiella burnetii outer membrane protein gene com1,” Infection and Immunity, vol. 61, no. 2, pp. 470–477, 1993.
[25]
Y.-Y. Mo, N. P. Cianciotto, and L. P. Mallavia, “Molecular cloning of a Coxiella burnetii gene encoding a macrophage infectivity potentiator (Mip) analogue,” Microbiology, vol. 141, no. 11, pp. 2861–2871, 1995.
[26]
S. Varghees, K. Kiss, G. Frans, O. Braha, and J. E. Samuel, “Cloning and porin activity of the major outer membrane protein P1 from Coxiella burnetii,” Infection and Immunity, vol. 70, no. 12, pp. 6741–6750, 2002.
[27]
M. H. Vodkin and J. C. Williams, “A heat shock operon in Coxiella burnetii produces a major antigen homologous to a protein in both mycobacteria and Escherichia coli,” Journal of Bacteriology, vol. 170, no. 3, pp. 1227–1234, 1988.
[28]
A. Papadioti, S. Markoutsa, I. Vranakis et al., “A proteomic approach to investigate the differential antigenic profile of two Coxiella burnetii strains,” Journal of Proteomics, vol. 74, no. 7, pp. 1150–1159, 2011.
[29]
L. Skultety, M. Hajduch, G. Flores-Ramirez et al., “Proteomic comparison of virulent phase I and avirulent phase II of Coxiella burnetii, the causative agent of Q fever,” Journal of Proteomics, vol. 74, no. 10, pp. 1974–1984, 2011.
[30]
A. Vigil, R. Ortega, R. Nakajima-Sasaki et al., “Genome-wide profiling of humoral immune response to Coxiella burnetii infection by protein microarray,” Proteomics, vol. 10, no. 12, pp. 2259–2269, 2010.
[31]
A. Vigil, C. Chen, A. Jain et al., “Profiling the humoral immune response of acute and chronic Q fever by protein microarray,” Molecular and Cellular Proteomics, vol. 10, no. 10, Article ID M110.006304, 2011.
[32]
F. W. Studier and B. A. Moffatt, “Use of bacteriophage T7 RNA polymerase to direct selective high-level expression of cloned genes,” Journal of Molecular Biology, vol. 189, no. 1, pp. 113–130, 1986.
[33]
H.-W. Chen, Z. Zhang, E. Huber et al., “Identification of cross-reactive epitopes on the conserved 47-kilodalton antigen of Orientia tsutsugamushi and human serine protease,” Infection and Immunity, vol. 77, no. 6, pp. 2311–2319, 2009.
[34]
P. Fiset , “Phase variation of Rickettsia (Coxiella) burneti; study of the antibody response in guinea pigs and rabbits,” Canadian Journal of Microbiology, vol. 3, no. 3, pp. 435–445, 1957.
[35]
P. Fiset and R. A. Ormsbee, “The antibody response to antigens of Coxiella burnetii,” Zentralblatt für Bakteriologie, Parasitenkunde, Infektionskrankheiten und Hygiene, vol. 206, no. 3, pp. 321–329, 1968.
[36]
P. Fiset, R. A. Ormsbee, R. Silberman, M. Peacock, and S. H. Spielman, “A microagglutination technique for detection and measurement of rickettsial antibodies,” Acta Virologica, vol. 13, no. 1, pp. 60–66, 1969.
[37]
M. G. Stoker and P. Fiset, “Phase variation of the Nine Mile and other strains of Rickettsia burneti,” Canadian Journal of Microbiology, vol. 2, no. 3, pp. 310–321, 1956.
[38]
G. Q. Zhang, H. To, T. Yamaguchi, H. Fukushi, and K. Hirai, “Differentiation of Coxiella burnetii by sequence analysis of the gene (com1) encoding a 27-kDa outer membrane protein,” Microbiology and Immunology, vol. 41, no. 11, pp. 871–877, 1997.
[39]
G. Q. Zhang, A. Hotta, T. Ho, T. Yamaguchi, H. Fukushi, and K. Hirai, “Evaluation of a recombinant 27-kDa outer membrane protein of Coxiella burnetii as an immunodiagnostic reagent,” Microbiology and Immunology, vol. 42, no. 6, pp. 423–428, 1998.
