| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
Correspondence |
1 Federal Institute for Risk Assessment (BfR), Department of Biological Safety, Unit for Molecular Diagnostic and Genetic, Diedersdorfer Weg 1, D-12277 Berlin, Germany
2 Charité, Campus Benjamin Franklin, Department for Infectious Diseases, Hindenburgdamm 30, 12203 Berlin, Germany
3 Charité, Campus Benjamin Franklin, Department for Pathology, Hindenburgdamm 30, 12203 Berlin, Germany
4 Robert Koch Institute (RKI), Department of Infectious Diseases Epidemiology, Seestraße. 10, 13353 Berlin, Germany
Correspondence
Beatriz Guerra
(beatriz.guerra{at}bfr.bund.de)
Leptospirosis is a re-emerging zoonotic disease that can be transmitted to humans by direct or indirect contact with the contaminated urine of infected animals (Levett, 2001). Rodents are an important reservoir of Leptospira (Faine et al., 1999; Levett, 2001). In Germany, leptospirosis is a notifiable disease with a low but increasing incidence (0.06 per 100 000 population, from 1998 to 2003) with 30–50 laboratory confirmed cases per year (Jansen et al., 2005). The microagglutination test (MAT) is the standard method for serological diagnosis (Levett, 2001; WHO, 2003), but antibodies are not detectable in blood until 5 to 7 days after the onset of symptoms (Levett, 2003).
Since leptospires are difficult to culture, several PCR methods have been used to facilitate early diagnosis (Gravekamp et al. 1993; Bal et al., 1994; Levett et al., 2005; Merien et al., 2005). In this study, white fancy rats (domestic albino Rattus norvegicus) were identified as the potential infection source for acute leptospirosis in a human immunodeficiency virus (HIV)-positive patient by using a combination of bacteriological, serological, histological and molecular methods.
A 39-year-old male patient was hospitalised due to a fever of sudden onset, myalgia, arthralgia and icterus, and Weil's disease was suspected. The patient was immunosuppressed due to an HIV-infection (824 CD3 cells µl–1, 250 CD4 cells µl–1 and 316 CD8 cells µl–1). Histological examination of a needle biopsy of the liver showed canalicular cholestasis and ballooning of hepatocytes by haematoxylin and eosin staining, and spiral-like bacteria by Warthin–Starry silver staining. These results confirmed the putative diagnosis of leptospirosis and helped to exclude HIV-related cholestasis (e.g. drug-induced hepatic injury or viral infection).
Blood samples taken 1 day after admission of the patient were analysed by Leptospira-specific PCR and bacterial culture. The sample gave positive results in a multiplex PCR with the G1/G2-B64I/II primers (Gravekamp et al., 1993; Bal et al., 1994) and classic PCR with the LipL32 F/B primers (Levett et al., 2005), generating amplicons of 285 and 423 bp, respectively. However, bacterial culture (Faine et al., 1999) was negative after 12 weeks, probably due to antibiotic treatment immediately after admission to the hospital. In a 9 month follow-up study, 6 sera were examined by MAT (Faine et al., 1999; WHO, 2003) performed with Leptospira strains belonging to 10 serogroups and 15 serovars (Table 1
). The first antibodies in serum were demonstrated 1 week after admission of the patient, and the highest titre (1 : 3200 serovar Icterohaemorrhagiae) was found at day 21. Cross-reactions with the serovars Copenhageni (1 : 200) and Sejroe (1 : 100) were detected, especially in the acute phase of the illness. Such cross-agglutinations with M84 Sejroe after serovar Icterohaemorrhagiae, Canicola or Pomona infections have been described by others as well (Brem et al., 1995). These unspecific reactions disappear during infection, when antibodies against the real causative agent become more predominant (Levett, 2001, 2003). Consequently, the presumptive causal agent of the infection belonged to Leptospira interrogans serogroup Icterohaemorrhagiae, since only serovars Copenhageni and Icterohaemorrhagiae (both with titres of 1 : 400) reacted in the last samples taken 9 months after admission.
|
In order to identify the source of infection, four white domestic rats owned by the patient were euthanized, and blood and kidney samples were taken. One kidney of each rat was tested for Leptospira by PCR analysis and bacterial culture. All four kidneys proved to be positive by both PCR methods (amplicons of 285 and 423 bp). Although cultures are relatively insensitive and require several weeks of incubation, all kidney samples were positive for Leptospira after 5 days as well. For serotyping, the four isolates were subjected to microagglutination (Faine et al., 1999) with 15 rabbit sera representing the reference strains (Table 1
). Cross-reactions with serovars Canicola and Pyrogenes were observed, but the highest titres were found with the antisera for serovars Copenhageni (1 : 6400–1 : 25 600) and Icterohaemorrhagiae (1 : 25 600–1 : 51 200).
Several molecular methods (including PFGE, random amplified polymorphic DNA analysis and RFLP) have been used for the typing of Leptospira isolates (Perolat et al., 1990; Taylor et al., 1991). For this study, two variants of multilocus variable analysis (MLVA), MLVA1 (Majed et al., 2005) and MLVA2 (Slack et al., 2005), were carried out. The four isolates yielded the same profiles by MLVA1 and MLVA2 as the L. interrogans serovars Icterohaemorrhagiae and Copenhageni reference strains (Fig. 1). Similar to PFGE (Taylor et al., 1991), MLVA typing was not able to differentiate between L. interrogans serovars Icterohaemorrhagiae and Copenhageni.
|
Altogether, this study suggests that the infection was due to L. interrogans serogroup Icterohaemorrhagiae, serovars Icterohaemorrhagiae or Copenhageni isolates originating from the patient's rats. The patient had no other known potential exposure to Leptospira. Unfortunately, direct isolates from the patient were not available and thus an absolute epidemiological link could not be established. However, there was strong diagnostic and epidemiological evidence that the pet rats were the source of infection. As far as we know, a relation between domestic rats held as pets and a severe leptospirosis in a HIV-positive patient has not been described before. During the last few years, the habit of keeping rats as pets has become a new fashion, and thus this kind of exposure with infected rats may pose a threat for public health.
ACKNOWLEDGEMENTS
We thank Dr M. Goris (Royal Tropical Institute, Amsterdam, The Netherlands) for the serological analysis with mAbs and her kind comments regarding the results.
REFERENCES
Bal, A. E., Gravekamp, C., Hartskeerl, R. A., de Meza-Brewster, J., Korver, H. & Terpstra, W. J. (1994). Detection of leptospires in urine by PCR for early diagnosis of leptospirosis. J Clin Microbiol 32, 1894–1898.
Brem, S., Radu, O., Bauer, T., Schonberg, A., Reisshauer, K., Waidmann, R., Kopp, H. & Meyer, P. (1995). Leptospira infected rat population as probable cause of a fatal case of Weil's disease. Berl Munch Tierarztl Wochenschr 108, 405–407.[Medline]
Faine, S., Adler, B., Bolin, C. & Perolat, P. (1999). Leptospira and Leptospirosis, 2nd edn. Melbourne: MedSci.
Gravekamp, C., van de Kemp, H., Franzen, M., Carrington, D., Schoone, G. J., van Eys, G. J. J. M., Everard, C. O. R., Hartskeerl, R. A. & Terpstra, W. J. (1993). Detection of seven species of pathogenic leptospires by PCR using two sets of primers. J Gen Microbiol 139, 1691–1700.
Jansen, A., Schoneberg, I., Frank, C., Alpers, K., Schneider, T. & Stark, K. (2005). Leptospirosis in Germany, 1962–2003. Emerg Infect Dis 11, 1048–1054.[Medline]
Jones, S. & Kim, T. (2001). Fulminant leptospirosis in a patient with human immunodeficiency virus infection: case report and review of the literature. Clin Infect Dis 33, 31–33.[CrossRef]
Levett, P. N. (2001). Leptospirosis. Clin Microbiol Rev 14, 296–326.
Levett, P. N. (2003). Usefulness of serologic analysis as a predictor of the infecting serovar in patients with severe leptospirosis. Clin Infect Dis 36, 447–452.[CrossRef][Medline]
Levett, P. N., Morey, R. E., Galloway, R. L., Turner, D. E., Steigerwalt, A. G. & Mayer, L. W. (2005). Detection of pathogenic leptospires by real-time quantitative PCR. J Med Microbiol 54, 45–49.
Majed, Z., Bellenger, E., Postic, D., Pourcel, C., Baranton, G. & Picardeau, M. (2005). Identification of variable-number tandem-repeat loci in Leptospira interrogans sensu stricto. J Clin Microbiol 43, 539–545.
Merien, F., Portnoi, D., Bourhy, P., Charavay, F., Berlioz-Arthaud, A. & Baranton, G. (2005). A rapid and quantitative method for the detection of Leptospira species in human leptospirosis. FEMS Microbiol Lett 249, 139–147.[Medline]
Perolat, P., Grimont, F., Regnault, B., Grimont, P. A. D., Fournie, E., Thevenet, H. & Baranton, G. (1990). rRNA gene restriction patterns of Leptospira: a molecular typing system. Res Microbiol 141, 159–171.[Medline]
Slack, A. T., Dohnt, M. F., Symonds, M. L. & Smythe, L. D. (2005). Development of a multiple-locus variable number of tandem repeat analysis (MLVA) for Leptospira interrogans and its application to Leptospira interrogans serovar Australis isolates from Far North Queensland, Australia. Ann Clin Microbiol Antimicrob 30, 4–10.
Taylor, K. A., Barbour, A. G. & Thomas, D. D. (1991). Pulsed-field gel electrophoretic analysis of leptospiral DNA. Infect Immun 59, 323–329.
WHO (2003). Human Leptospirosis: Guidance for Diagnosis, Surveillance and Control. Geneva: World Health Organization.
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| INT J SYST EVOL MICROBIOL | J MED MICROBIOL | MICROBIOLOGY | J GEN VIROL | ALL SGM JOURNALS |
