Serological Detection of Lyme Borreliosis Agents in Patients From Korea, 2005–2009

AbstractObjectivesLaboratory tests are now being used to identify seropositive cases in patients suspected of having a Lyme borreliosis (LB) infection. From 2005 to 2009, we analyzed the serological and epidemiological characteristics of 53 LB positive cases in Korea using immunoblot assay.MethodsDuring the five-year study period, a total of 1897 serum samples from suspected LB cases were referred to us for further laboratory diagnosis. The bacterial strains Borrelia afzeli pKo, Borrelia garinii 935T and Borrelia burgdorferi B31 were used for indirect immunofluorescent antibody assay. Immunoblot assay was performed using the recomBlot Borrelia.ResultsBased on the information from the clinicians, the main symptoms of LB infection were rash and fever (66.0%), neurological symptoms (30.2%), and arthritis (5.7%). Of the 53 cases, 16 (30.2%) were infected abroad and the remaining 37 cases (69.8%) were suspected to have been infected in Korea. Immunoblot assays detected high levels of the antigens p41 (FlaB) of B. burgdorferi and OspC of B. garinii in infected samples.ConclusionsThe causative bacteria of LB were not isolated from humans yet but from vector ticks and rodents in Korea, and a few cases were reported with serological diagnosis. Our results suggest that LB is present in all areas of Korea and indicate that B. garinii and B. burgdorferi may be the predominant bacteria in patients with LB. However, further studies are needed to isolate and identify the causative bacteria for LB in patients

Seroreactivity and Risk Factors Associated with Coxiella burnetii Infection among Cattle Slaughterhouse Workers in South Korea

Q fever, caused by Coxiella burnetii, is a zoonotic disease that is an occupational hazard to people who work in close contact with animals or their carcasses. A nationwide serologic study among cattle slaughterhouse workers who were presumed to be at risk of having C. burnetii infection in South Korea was performed to investigate the seroreactivity of C. burnetii infection and identify related risk factors. Out of 1017 cattle slaughterhouse workers in South Korea, 923 (90.8%) participated in this cross-sectional study. Samples were tested for immunoglobulin G (IgG) and M (IgM) antibodies against phase II C. burnetii via indirect immunofluorescence assay. The overall seroreactivity, defined as IgG or IgM antibody titer cutoffs ≥1:16, was 9.1% (84/923). Additionally, a significant association was found between the seroreactivity of C. burnetii infection and performing carcass evisceration work (odds ratio, 2.36; 95% confidence interval, 1.39–4.03) in multivariate analysis. To diminish C. burnetii infection, cattle slaughterhouse workers need to take precautions during the evisceration process

Seroreactivity to Q Fever Among Slaughterhouse Workers in South Korea

Objectives Q fever is a zoonotic disease that occurs worldwide; however, little is known about its prevalence in South Korea. We attempted to determine the prevalence of Q fever seroreactivity among Korean slaughterhouse workers and the risk factors for seroreactivity according to the type of work. Methods The study was conducted among 1503 workers at a total of 73 slaughterhouses and 62 residual-product disposal plants. During the study period, sites were visited and surveys were administered to employees involved in slaughterhouse work, and serological tests were performed on blood samples by indirect immunofluorescence assays. Serological samples were grouped by job classification into those of slaughter workers, residual-product handlers, inspectors and inspection assistants, and grading testers and testing assistants. Employee risk factors were analyzed according to the type of work. Results Out of 1481 study subjects who provided a blood sample, 151 (10.2%) showed reactive antibodies. When these results were analyzed in accordance with the type of work, the result of slaughter workers (11.3%) was similar to the result of residual-product handlers (11.4%), and the result of inspectors and assistants (5.3%) was similar to the result of grading testers and assistants (5.4%). Among those who answered in the affirmative to the survey question, “Has there been frequent contact between cattle blood and your mouth while working?” the proportions were 13.4 and 4.6%, respectively, and this was identified as a risk factor that significantly varied between job categories among slaughterhouse workers. Conclusions This study found a Q fever seroreactivity rate of 10.2% for slaughterhouse workers, who are known to be a high-risk population. Contact with cattle blood around the mouth while working was the differential risk factor between job categories among slaughterhouse workers

Lon Mutant of Brucella abortus Induces Tumor Necrosis Factor-Alpha in Murine J774.A1 Macrophage

AbstractObjectivesThe objective of this study was to isolate a Brucella lon mutant and to analyze the cytokine response of B. lon mutant during macrophage infection.MethodsA wild-type Brucella abortus strain was mutagenized by Tn5 transposition. From the mouse macrophage J774.A1 cells, total RNA was isolated at 0 hours, 6 hours, 12 hours, and 24 hours after infection with Brucella. Using mouse cytokine microarrays, we measured transcriptional levels of the cytokine response, and validated our results with a reverse transcriptase-polymerase chain reaction (RT-PCR) assay to confirm the induction of cytokine messenger RNA (mRNA).ResultsIn host J774.A1 macrophages, mRNA levels of T helper 1 (Th1)-type cytokines, including tumor necrosis factor-alpha (TNF-α), interferon-gamma (IFN-γ), interleukin-2 (IL-2), and IL-3, were significantly higher in the lon mutant compared to wild-type Brucella and the negative control. TNF-α levels in cell culture media were induced as high as 2 μg/mL after infection with the lon mutant, a greater than sixfold change.ConclusionIn order to understand the role of the lon protein in virulence, we identified and characterized a novel B. lon mutant. We compared the immune response it generates to the wild-type Brucella response in a mouse macrophage cell line. We demonstrated that the B. lon mutants induce TNF-α expression from the host J774.A1 macrophage

Metabolic Responses to <i>Orientia tsutsugamushi</i> Infection in a Mouse Model

<div><p>Tsutsugamushi disease is an infectious disease transmitted to humans through the bite of the <i>Orientia tsutsugamushi</i>-infected chigger mite; however, host-pathogen interactions and the precise mechanisms of damage in <i>O. tsutsugamushi</i> infections have not been fully elucidated. Here, we analyzed the global metabolic effects of <i>O. tsutsugamushi</i> infection on the host using ¹H-NMR and UPLC-Q-TOF mass spectroscopy coupled with multivariate statistical analysis. In addition, the effect of <i>O. tsutsugamushi</i> infection on metabolite concentrations over time was analyzed by two-way ANOVAs. Orthogonal partial least squares-discriminant analysis (OPLS-DA) showed distinct metabolic patterns between control and <i>O. tsutsugamushi</i>-infected mice in liver, spleen, and serum samples. <i>O. tsutsugamushi</i> infection caused decreased energy production and deficiencies in both remethylation sources and glutathione. In addition, <i>O. tsutsugamushi</i> infection accelerated uncommon energy production pathways (i.e., excess fatty acid and protein oxidation) in host body. Infection resulted in an enlarged spleen with distinct phospholipid and amino acid characteristics. This study suggests that metabolite profiling of multiple organ tissues and serum could provide insight into global metabolic changes and mechanisms of pathology in <i>O. tsutsugamushi</i>-infected hosts.</p></div

Summary of metabolites in spleen tissue.

a<p>Arrows (↓ and ↑) represent a decrease or increase in metabolite levels with significant changes in <i>O. tsutsugamushi</i>-infected mice compared with control mice on day 4 and/or day 7.</p>b<p>No significant change. Levels were estimated based on intensities of ¹H-NMR spectra of a spleen following spectral normalization. s, singlet; d, doublet; q, quartet; t, triplet, m, multiplet; br, broad; *, <i>p</i> <0.05.</p><p>Summary of metabolites in spleen tissue.</p

IFA reactivity according to RABV strain and infected cell type.

<p>(A) BHK-21 cells and (B) N2a cells. The cells were infected with the KGH, CVS-11, and ERA strains for 48 h. The results were observed under a fluorescence microscope at a magnification 400×.</p

Development and evaluation of an anti-rabies virus phosphoprotein-specific monoclonal antibody for detection of rabies neutralizing antibodies using RFFIT

<div><p>Background</p><p>Rabies is a major public health problem with a fatality rate close to 100%; however, complete prevention can be achieved through pre- or post-exposure prophylaxis. The rapid fluorescent focus inhibition test (RFFIT) is one of the recommended testing methods to determine the production of neutralizing antibodies after vaccination. Here, we report the development of a new monoclonal antibody (mAb) designed to react specifically with <i>Rabies virus</i> (RABV) phosphoprotein (P protein), and the evaluation of its applicability to the RFFIT and its effectiveness as a diagnostic reagent for human rabies.</p><p>Methodology/principal findings</p><p>The mAb KGH P 16B8 was produced to target the P protein of the Korean KGH RABV strain. An indirect immunofluorescence assay (IFA) was conducted to detect various strains of RABV in various cell lines. Alexa-conjugated KGH P 16B8 (16B8-Alexa) was developed for the RFFIT. The IFA test could detect RABV up to a 1:2,500 dilution, with a detection limit comparable to that of a commercial diagnostic reagent. The sensitivity, specificity, positive predictive value, and negative predictive value of the RFFIT using 16B8-Alexa in 414 clinical specimens were 98.67%, 99.47%, 99.55%, and 98.42%, respectively. The results of the RFFIT with 16B8-Alexa were strongly correlated with those obtained using an existing commercial diagnostic reagent (r = 0.995, <i>p</i><0.001).</p><p>Conclusions/significance</p><p>The mAb developed in this study shows high sensitivity and specificity, confirming its clinical utility with the RFFIT to measure the rabies neutralizing antibody titer and establish a diagnosis in human. Thus, 16B8-Alexa is expected to serve as an alternative diagnostic reagent that is widely accessible, with potentially broad applications beyond those of the RFFIT in Korea. Further studies with 16B8-Alexa should provide insight into the immunological mechanism of the P protein of Korean RABV.</p></div

Body weight, spleen length, and AST and ALT levels.

<p>*, <i>p</i><0.05; ** <i>p</i><0.01; ***, <i>p</i><0.001 for control vs. <i>O. tsutsugamushi</i>-infected mice.</p