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[Significance of human leptospirosis in Mexico. Detection of Leptospira antibodies in a blood donor population].

The presence of specific serum antibodies has been used as a diagnostic test for human leptospirosis. The presence of these antibodies in humans is indicative of an active natural infection. Its detection after exposure denotes the presence of immunity. Serum samples from 206 adult blood donors were analyzed with a microscopic agglutination assay against 7 serovars of Leptospira interrogans. A total of 7% were positive with the following serovar distribution; shermani 53%, canicola 33%, pyrogens 20%, pomona 13% and icterohaemorrhagiae 6%. The highest frequency of seropositivity was found in the 20 year to 39 age group. These results in asymptomatic individuals show that leptospirosis is a frequent zoonosis in Mexico.

Adolescent↗

C3 fixed in vivo to cornea from horses inoculated with Leptospira interrogans.

C3 was detected bound in vivo to the opaque cornea of horses inoculated with killed Leptospira interrogans. Employing epithelial corneal cells isolated from a monolayer in tissue culture, we proved that C3 is fixed in vitro to the intact cell surface after incubation with a fresh equine anti-Leptospira serum. These findings, in addition to the infiltration of cornea with neutrophils and lymphocytes, may explain the mechanisms of tissue damage in recurrent uveitis of horses with leptospirosis.

Animals↗

[Epidemiologic evaluation of a sample of 91 rats (Rattus norvegicus) captured in the sewers of Lyon].

91 rats captured in 1982 in the sewers of Lyon (France) have been examined for the presence of some microorganisms implicated in infections transmissible to man, by direct examination, bacteriological culture or detection of specific antibodies. Bacteriological results have shown a high proportion of carriers of Yersinia enterocolitica and frederiksenii (29%), of Pasteurella pneumotropica (29%), of Staphylococcus aureus (53%), and of Campylobacter jejuni (18%), a low proportion of carriers of Salmonella typhimurium (6%) and Leptospira (7%), and an absence of Listeria. Immunological reactions were often positive with Leptospira (21%), sometimes with Salmonella typhimurium, and always negative with Yersinia and Listeria. This work is a contribution to the knowledge of the health status of sewer rats considered to be an important public health risk as transmitters of anthropozoonoses.

Animals↗

Purification and proteomic analysis of outer membrane vesicles from a clinical isolate of Leptospira interrogans serovar Copenhageni.

The severe pulmonary form of leptospirosis (SPFL) is an especially serious and rapid disease process characterized by alveolar hemorrhage and acute respiratory failure. The outer membrane of Leptospira facilitates direct interactions with the environs and likely contains important constituents involved during infection, transmission, survival, and adaptation to environmental conditions, including putative vaccinogen and diagnostic candidates. Outer membrane vesicles (OMVs) were purified by incubation in low-pH citrate buffer, treatment in a French press, and centrifugation over a continuous sucrose gradient. OMVs characterized by two-dimensional gel electrophoresis (2-DE) contained the previously described outer membrane proteins OmpL1, Qlp42, LipL32, LipL41, LipL36 and Loa22. In addition, unknown, hypothetical and putative outer membrane proteins were identified. High-performance liquid chromatography (HPLC) coupled with mass spectrometry and fraction collection (LC-MS+) measured the intact mass profile of the major outer membrane protein, LipL32, and the putative lipoprotein Qlp42. In contrast to a predicted molecularmass of 27,653.5 Da for LipL32 after cleavage of its signal peptide, intact mass proteomics measured the mass as ranging from 28,468 to 28,583 Da, consistent with lipidation of LipL32. In contrast to a predicted molecular mass of 39.8 kDa for Qlp42, the actual mass was measured as 24,811 and 26,461 Da consistent with a 30 kDa doublet observed on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) gels and processing of the N-terminus of the mature protein. These studies indicate that purified OMVs are highly compatible with proteomics technologies including 2-DE and intact mass proteomics using LC-MS+ that facilitates definition of actual molecular masses of intact outer membrane proteins, and heterogeneity associated with them.

Amino Acid Sequence↗

Seroepidemiologic study of three zoonoses (leptospirosis, Q fever, and tularemia) among trappers in Québec, Canada.

This study was undertaken to evaluate the prevalence of antibodies against Francisella tularensis, Coxiella burnetii, and certain serovars of Leptospira interrogans among trappers in Québec, Canada. Muskrat trapping was identified as a risk factor for F. tularensis infection, whereas having a cat at home apparently protected trappers against infection by L. interrogans. High percentages of control sera were positive for antibodies against C. burnetii (15%) and L. interrogans (5%), most frequently serovar bratislava. This is the first report of human infection by serovar bratislava in North America.

Adult↗

Temperature-regulated protein synthesis by Leptospira interrogans.

Leptospira interrogans is an important mammalian pathogen. Transmission from an environmental source requires adaptations to a range of new environmental conditions in the organs and tissues of the infected host. Since many pathogenic bacteria utilize temperature to discern their environment and regulate the synthesis of appropriate proteins, we investigated the effects of temperature on protein synthesis in L. interrogans. Bacteria were grown for several days after culture temperatures were shifted from 30 to 37 degrees C. Triton X-114 cellular fractionation identified several proteins of the cytoplasm, periplasm, and outer membrane for which synthesis was dependent on the culture temperature. Synthesis of a cytoplasmic protein of 20 kDa was switched off at 37 degrees C, whereas synthesis of a 66-kDa periplasmic protein was increased at the higher temperature. Increased synthesis of a 25-kDa outer membrane protein was observed when the organisms were shifted from 30 to 37 degrees C. A 36-kDa protein synthesized at 30 but not at 37 degrees C was identified as LipL36, an outer membrane lipoprotein. In contrast, expression of another lipoprotein, LipL41, was the same at either temperature. Immunoblotting with convalescent equine sera revealed that some proteins exhibiting thermoregulation of synthesis elicited antibody responses during infection. Our results show that sera from horses which aborted as a result of naturally acquired infection with L. interrogans serovar pomona type kennewicki recognize periplasmic and outer membrane proteins which are differentially synthesized in response to temperature and which therefore may be important in the host-pathogen interaction during infection.

Antigens, Bacterial↗

Bacterial agents detected in a 10-year study of bovine abortions and stillbirths.

In a 10-year survey started in 1980, specimens from 8,995 bovine abortions and stillbirths were submitted to the South Dakota Animal Disease Research and Diagnostic Laboratory. Of these, 8,962 were suitable for some type of examination. Bacteria were determined to be the cause of 1,299 (14.49%). The 5 bacteria most commonly associated with bovine abortion or stillbirth were Actinomyces pyogenes, 378 (4.22%); Bacillus spp., 321 (3.58%); Listeria spp., 121 (1.35%); Escherichia coli, 98 (1.09%); and Leptospira interrogans, 79 (0.88%). Twelve other genera of bacteria were associated with > or = 10 abortions or stillbirths, and 12 more species were associated with < or = 10 abortions or stillbirths.

Abortion, Veterinary↗

Molecular characterization of thermoinduced immunogenic proteins Q1p42 and Hsp15 of Leptospira interrogans.

Leptospira interrogans is a mammalian pathogen which must adapt to a range of new environmental conditions including temperature change when it infects new hosts. In vitro studies of organisms cultured at 30 degrees C and shifted to 37 degrees C for 5 to 7 days have confirmed that synthesis of several proteins involved in equine infection is regulated in response to temperature change (J. E. Nally, J. F. Timoney, and B. Stevenson, Infect. Immun. 69:400-404, 2001). In order to specifically identify antigenic proteins upregulated at 37 degrees C, groups of three ponies were immunized with organisms shifted to 37 degrees C for 5 to 7 days or with organisms maintained at 30 degrees C. A lambda ZAP II genomic DNA library was screened with the pool of antisera to organisms shifted to 37 degrees C. Clones reactive with this pool but unreactive with the pool of pony antisera to organisms cultured at 30 degrees C were selected for further analysis. Sequence analysis of the first two clones identified open reading frames for proteins designated Qlp42 and Hsp15. Qlp42 is predicted to be an outer membrane lipoprotein. Its synthesis was upregulated when cultures were shifted from 30 to 37 degrees C and downregulated when cultures were shifted from 37 to 30 degrees C. Although the predicted molecular mass of Qlp42 is 39.8 kDa for the mature protein, Qlp42-specific equine antiserum was reactive with two bands of 30 and 29.5 kDa. Hsp15 is a stress response protein and a member of the Hsp20/alpha-crystallin family. PCR detected homologues of qlp42 and hsp15 in pathogenic serovars of L. interrogans but not in the nonpathogenic Leptospira biflexa. Enzyme-linked immunosorbent assays of antibody in convalescent sera from mares naturally infected with L. interrogans suggest that Qlp42 is expressed during leptospiral infection.

Amino Acid Sequence↗

Prevalence of selected pathogenic microbial agents in the red fox (Vulpes fulva) and gray fox (Urocyon cinereoargenteus) of southwestern Wisconsin.

Free-ranging red foxes (Vulpes fulva) and gray foxes (Urocyon cinereoargenteus) were trapped in southwestern Wisconsin. Fox sera were tested to determine the prevalence of antibody for five different Leptospira interrogans serovars, canine distemper virus (CDV), infectious canine hepatitis virus (ICHV), and Franciscella tularensis infections. Grippotyphosa was the most prevalent leptospiral serovar antibody observed. Twenty-five of 53 (47%) red foxes and 11 of 36 (31%) gray foxes had specific antibodies to grippotyphosa. Juvenile foxes had geometric mean antibody titers to grippotyphosa significantly higher (P less than 0.05) than those of the adults of both species. CDV antibody was detected in sera of red foxes only. Six of 57 (11%) red foxes had CDV antibody. ICHV antibody was detected in 2 of 57 (3%) red foxes and 3 of 32 (9%) gray foxes. Antibody to F. tularensis was not detected in any fox sera.

Adenoviruses, Canine↗

Update: outbreak of acute febrile illness among athletes participating in Eco-Challenge-Sabah 2000--Borneo, Malaysia, 2000.

During September 7-11, 2000, CDC was notified by the Idaho Department of Health, the Los Angeles County Department of Health Services, and the GeoSentinel Global Surveillance Network of at least 20 cases of acute febrile illness in three countries; all ill patients had participated in the Eco-Challenge-Sabah 2000 multisport expedition race in Borneo, Malaysia, during August 21-September 3, 2000. Participants included athletes from 29 U.S. states and 26 countries. This report updates the ongoing investigation of this outbreak through December 2, which suggests that Leptospira were the cause of illness and that water from the Segama River was the primary source of infection. Participants in adventure sports and exotic tourism should be aware of potential exposure to unusual and emerging infectious agents.

Acute Disease↗

The leptospiral major outer membrane protein LipL32 is a lipoprotein expressed during mammalian infection.

We report the cloning of the gene encoding the 32-kDa lipoprotein, designated LipL32, the most prominent protein in the leptospiral protein profile. We obtained the N-terminal amino acid sequence of a staphylococcal V8 proteolytic-digest fragment to design an oligonucleotide probe. A Lambda-Zap II library containing EcoRI fragments of Leptospira kirschneri DNA was screened, and a 5.0-kb DNA fragment which contained the entire structural lipL32 gene was identified. Several lines of evidence indicate that LipL32 is lipid modified in a manner similar to that of other procaryotic lipoproteins. The deduced amino acid sequence of LipL32 would encode a 272-amino-acid polypeptide with a 19-amino-acid signal peptide, followed by a lipoprotein signal peptidase cleavage site. LipL32 is intrinsically labeled during incubation of L. kirschneri in media containing [(3)H]palmitate. The linkage of palmitate and the amino-terminal cysteine of LipL32 is acid labile. LipL32 is completely solubilized by Triton X-114 extraction of L. kirschneri; phase separation results in partitioning of LipL32 exclusively into the hydrophobic, detergent phase, indicating that it is a component of the leptospiral outer membrane. CaCl(2) (20 mM) must be present during phase separation for recovery of LipL32. LipL32 is expressed not only during cultivation but also during mammalian infection. Immunohistochemistry demonstrated intense LipL32 reactivity with L. kirschneri infecting proximal tubules of hamster kidneys. LipL32 is also a prominent immunogen during human leptospirosis. The sequence and expression of LipL32 is highly conserved among pathogenic Leptospira species. These findings indicate that LipL32 may be important in the pathogenesis, diagnosis, and prevention of leptospirosis.

Acylation↗

Borreliosis in dogs from southern Connecticut.

Blood samples were obtained from dogs in tick-infested regions of southern Connecticut to assess canine exposure to Borrelia burgdorferi, the etiologic agent of Lyme disease in human beings. An indirect fluorescent antibody test detected immunoglobulin (Ig)M antibodies at titers of 1:64 to 1:512 in 22 of 84 serum samples previously shown to be positive with a polyvalent rabbit anti-dog total Ig conjugate. Analyses of paired serum samples from 20 seropositive dogs revealed temporal differences in titers; changes occurred during brief (1 month) or extended (greater than 4 years) sampling periods. Clinical records for 52 seropositive dogs indicated a history of intermittent lameness in 19 of these. Limb/joint disorders typically developed in dogs without IgM antibodies, suggesting manifestation during later phases of illness. A microscopic-agglutination test was used to assess cross reactivity between B burgdorferi and 20 serovars of Leptospira interrogans and biflexa. Analyses of 63 dog serum specimens with antibodies to B burgdorferi and a series of reference rabbit sera revealed minor antigenic relatedness. There was geographic clustering of dogs with antibodies to B burgdorferi in areas of south-central and southeastern Connecticut, where human Lyme disease also occurs.

Animals↗

A twelve-year study of leptospirosis on Barbados.

Between November 1979 and December 1991, 398 cases of severe leptospirosis were confirmed on Barbados (range for 1980-1991 23-56; mean 32.7; incidence 13.3/100,000/year). For the six-year periods 1980-1985 and 1986-1991 there was no significant change in incidence with time. Incidence is unlikely to change significantly in the next decade. Monthly average case numbers ranged from 1.4 (July) to 4.3 (November). The average (2.8) for June to December (the 7 wetter months) was not significantly higher than that (2.5) for January to May (the 5 drier months). The age range was 7-86. There were three times as many male cases (302) as female (96), and nearly 10 times as many in those < 35. Although the highest number of cases (69) was in males aged 15-24, the highest incidence was in the older age groups, particularly the male 65-74 year-olds, and the female 55-64 year-olds. Leptospirosis was the proven cause of death in 55 (13.8%) hospital patients (annual range 0-13, mean 4.5). Some of a further 39 fatalities might have been cases. Death from leptospirosis was nearly twice as common among the women as among the men. Only one patient under 20 years of age died. Leptospira were isolated and identified from 117 (29.4%) of the 398 sick patients. The infecting organisms were bim (serogroup Autumnalis--75), copenhageni (Icterohaemorrhagiae-26), arborea (Ballum-14) and bajan (Australis-2). These infecting serovars could not be distinguished clinically, but infection was milder in children than in adults. Despite its predominance in surveyed children, serogroup Panama was virtually absent in this study. Rainfall is the major factor affecting the distribution of cases; not surprisingly, sanitation workers and agricultural workers appear to be the groups at highest risk. The general lack of clear-cut risk factors reflects the ubiquity of leptospires in the environment and the fact that the disease is not entirely occupational.

Adolescent↗

Genome-wide transcriptional analysis of temperature shift in L. interrogans serovar lai strain 56601.

BACKGROUND: Leptospira interrogans is an important mammalian pathogen. Transmission from an environmental source requires adaptation to a range of new environmental conditions in the organs and tissues of the infected host. Several studies have shown that a shift in culture temperature from 28 degrees C to 37 degrees C, similar to that encountered during infection of a host from an environmental source, is associated with differential synthesis of several proteins of the outer membrane, periplasm and cytoplasm. The whole genome of the Leptospira interrogans serogroup Icterohaemorrhagiae serovar lai type strain #56601 was sequenced in 2003 and microarrays were constructed to compare differential transcription of the whole genome at 37 degrees C and 28 degrees C. RESULTS: DNA microarray analyses were used to investigate the influence of temperature on global gene expression in L. interrogans grown to mid-exponential phase at 28 degrees C and 37 degrees C. Expression of 106 genes differed significantly at the two temperatures. The differentially expressed genes belonged to nine functional categories: Cell wall/membrane biogenesis genes, hemolysin genes, heat shock proteins genes, intracellular trafficking and secretion genes, two-component system and transcriptional regulator genes, information storage and processing genes, chemotaxis and flagellar genes, metabolism genes and genes with no known homologue. Real-time reverse transcription-PCR assays confirmed the microarray data. CONCLUSION: Microarray analyses demonstrated that L. interrogans responds globally to temperature alteration. The data delineate the spectrum of temperature-regulated gene expression in an important human pathogen and provide many new insights into its pathogenesis.

Bacterial Proteins↗

Serologic survey of California wild hogs for antibodies against selected zoonotic disease agents.

Blood samples were collected from trapped or hunter-killed wild hogs (Sus scrofa) in 4 areas of California. Sera were tested for antibodies against 7 zoonotic disease agents. Antibodies against Brucella sp were detected in 21 (15%) of 136 samples. Antibodies against Coxiella burnetii were found in 50% of the collected samples (67 of 135 tested). Of the 135 wild hogs screened for pseudorabies virus, 4 (3%) were seropositive. Leptospira interrogans antibodies were discovered in 118 (87%) of the 136 samples tested. Of the 130 samples screened for antibodies against Mycobacterium avium complex, 111 (85%) were seropositive. Antibodies against Toxoplasma gondii were detected in 17 (13%) of 135 wild hogs. Antibodies against Yersinia pestis were found in 9 (15%) of 59 sera tested.

Animal Population Groups↗

New infectious spirochete isolated from short-tailed shrews and white-footed mice.

A spirochete with two periplasmic flagella was isolated from the blood or tissues of spleens and kidneys from short-tailed shrews (Blarina brevicauda) and white-footed mice (Peromyscus leucopus) in Connecticut and Minnesota. After inoculation, the shrew-mouse spirochete infected Swiss mice and Syrian hamsters. This spirochete is morphologically and serologically distinct from the species of Treponema, Borrelia, Leptospira, and Spirochaeta examined.

Animals↗