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Background@#Whether varicella zoster virus (VZV) antibody titer could discriminate patients with herpes zoster (HZ) from healthy controls (HCs) is unclear. We evaluated the diagnostic usefulness of VZV-specific immunoglobulin A (IgA) and immunoglobulin G (IgG) antibodies in patients with confirmed HZ. @*Methods@#Study subjects comprised patients with confirmed HZ by salivary VZV DNA positivity and control age- and sex-matched HCs. Saliva was collected and concurrent blood samples were obtained on the first visit day (acute phase) and after 4 weeks (convalescent phase) from 44 HZ patients. All 44 healthy volunteers provided blood and saliva samples once. @*Results@#The median VZV IgA titers in acute-phase (5.2 mIU/mL, P < 0.001) and convalescentphase (15.8 mIU/mL, P < 0.001) serum samples from HZ patients were significantly higher than those in HCs (1.35 mIU/mL). VZV IgA positivity was detected in about 20% of acute phase serum and convalescent-phase serum of HZ patients. The median VZV IgG antibody titers of HZ patients during acute (1,471.0 mIU/mL, P < 0.001) and convalescent (4,934.7 mIU/mL, P < 0.001) phases were significantly higher than the median titer reported for HCs (591.6 mIU/mL). A four-fold or higher increase in VZV IgG antibody titer was observed in 36.4% of HZ patients. @*Conclusion@#VZV IgA positivity or four-fold or higher increase in VZV IgG antibody titers were not detected in a satisfactory proportion of HZ-infected patients. However, the titer of VZV IgA or IgG antibody particularly in convalescent-phase sera may discriminate HZ patients from HCs.
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Plasmodium vivax exhibits dormant liver-stage parasites, called hypnozoites, which can cause relapse of malaria. The only drug currently used for eliminating hypnozoites is primaquine. The antimalarial properties of primaquine are dependent on the production of oxidized metabolites by the cytochrome P450 isoenzyme 2D6 (CYP2D6). Reduced primaquine metabolism may be related to P. vivax relapses. We describe a case of 4 episodes of recurrence of vivax malaria in a patient with decreased CYP2D6 function. The patient was 52-year-old male with body weight of 52 kg. He received total gastrectomy and splenectomy 7 months before the first episode and was under chemotherapy for the gastric cancer. The first episode occurred in March 2019 and each episode had intervals of 34, 41, and 97 days, respectively. At the first and second episodes, primaquine was administered as 15 mg for 14 days. The primaquine dose was increased with 30 mg for 14 days at the third and fourth episodes. Seven gene sequences of P. vivax were analyzed and revealed totally identical for all the 4 samples. The CYP2D6 genotype was analyzed and intermediate metabolizer phenotype with decreased function was identified.
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The coronavirus disease 2019 (COVID-19) pandemic is being overcome by widespread inoculation with various COVID-19 vaccines, but concerns about the safety of the vaccines are a major hurdle to widespread vaccination. We report the first case of adult-onset Still’s disease (AOSD) developing in a 36-year-old, previously healthy woman after the first dose of BNT162b2 mRNA COVID-19 vaccine (Pfizer). She visited our hospital due to high spiking fever and sore throat that developed 10 days after vaccination. Based on thorough investigations and changes in symptoms and signs after admission, she was diagnosed with AOSD and treated with high dose steroids and tocilizumab. This report suggests the possibility that AOSD could be triggered by COVID-19 vaccines through activation of the innate immune system.
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Background/Aims@#The risk of herpes zoster (HZ) is increased in patients with autoimmune diseases (AID), probably due to immunosuppressive therapy. @*Methods@#This prospective cross-sectional study investigated varicella zoster virus (VZV)-specific immunity in relation to subclinical VZV reactivation in 48 AID patients and 48 healthy controls (HCs). We assessed humoral immunity (serum VZV immunoglobulin g [IgG], IgA, and IgM) and cell-mediated immunity (interferon-γ [IFNγ]-releasing assay) to VZV as well as salivary VZV DNA status. Subclinical VZV reactivation was confirmed by detecting VZV DNA in saliva or VZV IgM in serum in the absence of typical HZ symptoms. @*Results@#Median IgA levels were higher in the AID group than in the HC group, while VZV IgG and IgM levels were comparable between the groups. AID patients showed fewer IFNγ spot-forming cells (SFCs) upon VZV stimulation than HCs (58.2 vs. 122.0 SFCs/106 peripheral blood mononuclear cells [PBMCs], p < 0.0001). Subclinical VZV reactivation was more frequent in AID patients than in HCs (12.5% vs. 0%, p = 0.01). AID patients with VZV reactivation received prednisolone more frequently and at a higher dose than AID patients without reactivation. VZV-specific IFNγ SFCs were significantly lower in patients with VZV reactivation among AID patients (26.3 vs. 62.6 SFCs/106 PBMCs, p < 0.0001). @*Conclusions@#Results suggest that poor cellular response against VZV might cause clinical and subclinical reactivation of VZV in AID patients.
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Background@#Tuberculous meningitis (TBM) is the most severe form of tuberculosis, but differentiating between the diagnosis of TBM and viral meningitis (VM) is difficult. Thus, we have developed machine-learning modules for differentiating TBM from VM.Material and Methods: For the training data, confirmed or probable TBM and confirmed VM cases were retrospectively collected from five teaching hospitals in Korea between January 2000 - July 2018. Various machine-learning algorithms were used for training. The machinelearning algorithms were tested by the leave-one-out cross-validation. Four residents and two infectious disease specialists were tested using the summarized medical information. @*Results@#The training study comprised data from 60 patients with confirmed or probable TBM and 143 patients with confirmed VM. Older age, longer symptom duration before the visit, lower serum sodium, lower cerebrospinal fluid (CSF) glucose, higher CSF protein, and CSF adenosine deaminase were found in the TBM patients. Among the various machinelearning algorithms, the area under the curve (AUC) of the receiver operating characteristics of artificial neural network (ANN) with ImperativeImputer for matrix completion (0.85; 95% confidence interval 0.79 - 0.89) was found to be the highest. The AUC of the ANN model was statistically higher than those of all the residents (range 0.67 - 0.72, P <0.001) and an infectious disease specialist (AUC 0.76; P = 0.03). @*Conclusion@#The machine-learning techniques may play a role in differentiating between TBM and VM. Specifically, the ANN model seems to have better diagnostic performance than the non-expert clinician.
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Background@#Pyomyositis (PM) is a serious soft tissue infection and despite its clinical importance, previous studies have not been able to fully determine the clinical characteristics and microbial epidemiology of PM in Korea, which we therefore aimed to investigate. @*Materials and Methods@#We retrospectively identified 140 adult patients diagnosed with PM from 13 general hospitals between January 2012 and December 2015. We analyzed the clinical and microbial characteristics of community-onset PM and compared them with communityacquired (CA) and healthcare-associated (HCA) PM. @*Results@#One hundred eleven organisms were isolated from 96 (68.6%) patients with PM.Staphylococcus aureus (38 patients) was the most common pathogen, followed by streptococci (24 patients), and enteric Gram-negative organisms (27 patients). Methicillin-resistant S.aureus (MRSA) was identified in four (2.9%) patients and in-hospital mortality reached 8.6% (12/140). Enterococci isolates were identified in the HCA PM subgroup only The proportion of MRSA isolates was not comparable between CA and HCA PM subgroups. In the 83 patients with PM infected by monomicrobial pathogens, isolates of Gram-negative organisms were more commonly found in HCA PM subgroup than in CA PM subgroup (47.6% [10/21] of patients with HCA PM vs. 20.7% [12/58] of patients with CA PM; P = 0.01). @*Conclusion@#Gram-positive cocci such as S. aureus and streptococci were dominant etiologies in community-onset PM, whereas MRSA appears to an uncommon causative organism of PM in Korea. Enteric Gram-negative organisms should also be considered as major etiologies, especially in HCA PM patient population in Korea.
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Background/Aims@#The risk of herpes zoster (HZ) is increased in patients with autoimmune diseases (AID), probably due to immunosuppressive therapy. @*Methods@#This prospective cross-sectional study investigated varicella zoster virus (VZV)-specific immunity in relation to subclinical VZV reactivation in 48 AID patients and 48 healthy controls (HCs). We assessed humoral immunity (serum VZV immunoglobulin g [IgG], IgA, and IgM) and cell-mediated immunity (interferon-γ [IFNγ]-releasing assay) to VZV as well as salivary VZV DNA status. Subclinical VZV reactivation was confirmed by detecting VZV DNA in saliva or VZV IgM in serum in the absence of typical HZ symptoms. @*Results@#Median IgA levels were higher in the AID group than in the HC group, while VZV IgG and IgM levels were comparable between the groups. AID patients showed fewer IFNγ spot-forming cells (SFCs) upon VZV stimulation than HCs (58.2 vs. 122.0 SFCs/106 peripheral blood mononuclear cells [PBMCs], p < 0.0001). Subclinical VZV reactivation was more frequent in AID patients than in HCs (12.5% vs. 0%, p = 0.01). AID patients with VZV reactivation received prednisolone more frequently and at a higher dose than AID patients without reactivation. VZV-specific IFNγ SFCs were significantly lower in patients with VZV reactivation among AID patients (26.3 vs. 62.6 SFCs/106 PBMCs, p < 0.0001). @*Conclusions@#Results suggest that poor cellular response against VZV might cause clinical and subclinical reactivation of VZV in AID patients.
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Background@#Tuberculous meningitis (TBM) is the most severe form of tuberculosis, but differentiating between the diagnosis of TBM and viral meningitis (VM) is difficult. Thus, we have developed machine-learning modules for differentiating TBM from VM.Material and Methods: For the training data, confirmed or probable TBM and confirmed VM cases were retrospectively collected from five teaching hospitals in Korea between January 2000 - July 2018. Various machine-learning algorithms were used for training. The machinelearning algorithms were tested by the leave-one-out cross-validation. Four residents and two infectious disease specialists were tested using the summarized medical information. @*Results@#The training study comprised data from 60 patients with confirmed or probable TBM and 143 patients with confirmed VM. Older age, longer symptom duration before the visit, lower serum sodium, lower cerebrospinal fluid (CSF) glucose, higher CSF protein, and CSF adenosine deaminase were found in the TBM patients. Among the various machinelearning algorithms, the area under the curve (AUC) of the receiver operating characteristics of artificial neural network (ANN) with ImperativeImputer for matrix completion (0.85; 95% confidence interval 0.79 - 0.89) was found to be the highest. The AUC of the ANN model was statistically higher than those of all the residents (range 0.67 - 0.72, P <0.001) and an infectious disease specialist (AUC 0.76; P = 0.03). @*Conclusion@#The machine-learning techniques may play a role in differentiating between TBM and VM. Specifically, the ANN model seems to have better diagnostic performance than the non-expert clinician.
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Background@#Pyomyositis (PM) is a serious soft tissue infection and despite its clinical importance, previous studies have not been able to fully determine the clinical characteristics and microbial epidemiology of PM in Korea, which we therefore aimed to investigate. @*Materials and Methods@#We retrospectively identified 140 adult patients diagnosed with PM from 13 general hospitals between January 2012 and December 2015. We analyzed the clinical and microbial characteristics of community-onset PM and compared them with communityacquired (CA) and healthcare-associated (HCA) PM. @*Results@#One hundred eleven organisms were isolated from 96 (68.6%) patients with PM.Staphylococcus aureus (38 patients) was the most common pathogen, followed by streptococci (24 patients), and enteric Gram-negative organisms (27 patients). Methicillin-resistant S.aureus (MRSA) was identified in four (2.9%) patients and in-hospital mortality reached 8.6% (12/140). Enterococci isolates were identified in the HCA PM subgroup only The proportion of MRSA isolates was not comparable between CA and HCA PM subgroups. In the 83 patients with PM infected by monomicrobial pathogens, isolates of Gram-negative organisms were more commonly found in HCA PM subgroup than in CA PM subgroup (47.6% [10/21] of patients with HCA PM vs. 20.7% [12/58] of patients with CA PM; P = 0.01). @*Conclusion@#Gram-positive cocci such as S. aureus and streptococci were dominant etiologies in community-onset PM, whereas MRSA appears to an uncommon causative organism of PM in Korea. Enteric Gram-negative organisms should also be considered as major etiologies, especially in HCA PM patient population in Korea.
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BACKGROUND: Carbapenem-resistant Acinetobacter baumannii (CRAB) infection is associated with high mortality. One of the strategies to reduce the mortality in patients with CRAB infections is to use intravenous colistin early but the effect of this strategy has not been proven. Therefore, we investigated the association of early colistin therapy with 28-day mortality in patients with CRAB bacteremia. METHODS: This retrospective multicenter propensity score-matching analysis was conducted in the Korea by reviewing the medical records of adult patients with CRAB bacteremia between January 2012 and March 2015. Early colistin therapy was defined as intravenous colistin administration for > 48 hours within five days after the blood culture collection. To identify the risk factors associated with the 28-day mortality in CRAB bacteremia, the clinical variables of the surviving patients were compared to those of the deceased patients. RESULTS: Of 303 enrolled patients, seventy-six (25.1%) patients received early colistin therapy. The 28-day mortality was 61.4% (186/303). Fatal or rapidly-fatal McCabe classifications, intensive care unit admission, Sequential Organ Failure Assessment scores ≥ 8, vasopressor use, and acute kidney injury were statistically independent poor prognostic factors. Catheter-related infection and early colistin therapy (adjusted odds ratio [aOR], 0.45; 95% confidence interval [CI], 0.21–0.94) were independent favorable prognostic factors associated with 28-day mortality in patients with CRAB bacteremia. Early colistin therapy was still significantly associated with lower 28-day mortality in the propensity score-matching analysis (aOR, 0.31; 95% CI, 0.11–0.88). CONCLUSION: This study suggests that early colistin therapy might help reduce the mortality of patients with CRAB bacteremia.
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Adulto , Humanos , Acinetobacter , Acinetobacter baumannii , Lesión Renal Aguda , Bacteriemia , Infecciones Relacionadas con Catéteres , Clasificación , Colistina , Unidades de Cuidados Intensivos , Corea (Geográfico) , Registros Médicos , Mortalidad , Oportunidad Relativa , Puntuaciones en la Disfunción de Órganos , Estudios Retrospectivos , Factores de RiesgoRESUMEN
BACKGROUND@#Vertebral osteomyelitis (VO) is a rare but serious condition, and a potentially significant cause of morbidity. Methicillin-susceptible Staphylococcus aureus (MSSA) is the most common microorganism in native VO. Long-term administration of parenteral and oral antibiotics with good bioavailability and bone penetration is required for therapy. Use of oral β-lactams against staphylococcal bone and joint infections in adults is not generally recommended, but some experts recommend oral switching with β-lactams. This study aimed to describe the current status of antibiotic therapy and treatment outcomes of oral switching with β-lactams in patients with MSSA VO, and to assess risk factors for treatment failure.@*MATERIALS AND METHODS@#This retrospective study included adult patients with MSSA VO treated at nine university hospitals in Korea between 2005 and 2014. Treatment failure was defined as infection-related death, microbiological relapse, neurologic deficits, or unplanned surgical procedures. Clinical characteristics and antibiotic therapy in the treatment success and treatment failure groups were compared. Risk factors for treatment failure were identified using the Cox proportional hazards model.@*RESULTS@#A total of 100 patients with MSSA VO were included. All patients were treated, initially or during antibiotic therapy, with one or more parenteral antibiotics. Sixty-nine patients received one or more oral antibiotics. Antibiotic regimens were diverse and durations of parenteral and oral therapy differed, depending on the patient and the hospital. Forty-two patients were treated with parenteral and/or oral β-lactams for a total duration of more than 2 weeks. Compared with patients receiving parenteral β-lactams only, no significant difference in success rates was observed in patients who received oral β-lactams for a relatively long period. Sixteen patients had treatment failure. Old age (adjusted hazard ratio [HR] 5.600, 95% confidence interval [CI] 1.402 – 22.372, P = 0.015) and failure to improve C-reactive protein levels at follow-up (adjusted HR 3.388, 95% CI 1.168 – 9.829, P = 0.025) were independent risk factors for treatment failure.@*CONCLUSION@#In the study hospitals, diverse combinations of antibiotics and differing durations of parenteral and oral therapy were used. Based on the findings of this study, we think that switching to oral β-lactams may be safe in certain adult patients with MSSA VO. Since limited data are available on the efficacy of oral antibiotics for treatment of staphylococcal VO in adults, further evaluation of the role of oral switch therapy with β-lactams is needed.
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BACKGROUND/AIMS@#Procalcitonin (PCT) may prove to be a useful marker to exclude or predict bloodstream infection (BSI). However, the ability of PCT levels to differentiate BSI from non-BSI episodes has not been evaluated in nosocomial BSI.@*METHODS@#We retrospectively reviewed the medical records of patients ≥ 18 years of age with suspected BSI that developed more than 48 hours after admission.@*RESULTS@#Of the 785 included patients, 105 (13.4%) had BSI episodes and 680 (86.6%) had non-BSI episodes. The median serum PCT level was elevated in patients with BSI as compared with those without BSI (0.65 ng/mL vs. 0.22 ng/mL, p = 0.001). The optimal PCT cut-off value of BSI was 0.27 ng/mL, with a corresponding sensitivity of 74.6% (95% confidence interval [CI], 66.4% to 81.7%) and a specificity of 56.5% (95% CI, 52.7% to 60.2%). The area under curve of PCT (0.692) was significantly larger than that of C-reactive protein (CRP; 0.526) or white blood cell (WBC) count (0.518). However, at the optimal cut-off value, PCT failed to predict BSI in 28 of 105 cases (26.7%). The PCT level was significantly higher in patients with an eGFR < 60 mL/min/1.73 m² than in those with an eGFR ≥ 60 mL/min/1.73 m² (0.68 vs. 0.17, p = 0.01).@*CONCLUSIONS@#PCT was more useful for predicting nosocomial BSI than CRP or WBC count. However, the diagnostic accuracy of predicting BSI remains inadequate. Thus, PCT is not recommended as a single diagnostic tool to avoid taking blood cultures in the nosocomial setting.
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BACKGROUND/AIM: Antimicrobials for nosocomial infections are generally chosen discriminately from community-acquired diseases from concerns for resistance to which the elderly are highly exposed. The elderly are affected frequently by acute cholecystitis (AC), for which appropriate antimicrobial therapy is particularly important. Also, cholecystectomy for elderly patients with co-morbidities is expectedly not as feasible as for uncomplicated young patients. Characteristics of hospital-acquired AC in the elderly patients were investigated in this study. METHODS: Records of patients over 65 years and older diagnosed with AC between March 2006 and February 2015 were reviewed retrospectively. Hospital-acquired AC was defined as development of AC in patients who were admitted for other disorders. Community-acquired AC was defined as presence of AC at the time of admission. Community-acquired AC group (CG) was used as a control group that was matched for age and sex with a ratio of 1:2. RESULTS: There were 40 patients in hospital-acquired AC group (HG) and 80 in CG. Demographics did not differ except higher prevalence of underlying illnesses in HG. Necessity to change initial antimicrobials for worsening conditions was more common in HG than in CG (20.0% vs. 2.5%, p < 0.01). Time to recovery was longer in HG (23.3 ± 5.6 days vs. 10.1 ± 0.7 days, p = 0.02). Rate of early cholecystectomy was lower (7.5% vs. 40.0%, p < 0.01) and that of open conversion was higher (20.0% vs. 6.3%, p = 0.02) in HG. CONCLUSIONS: For the elderly patients with hospital-acquired AC, antimicrobial and surgical management should be performed more meticulously since they showed distinct characteristics.
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Anciano , Humanos , Colecistectomía , Colecistitis Aguda , Infección Hospitalaria , Demografía , Cálculos Biliares , Prevalencia , Estudios RetrospectivosRESUMEN
Skin and soft tissue infection (SSTI) is common and important infectious disease. This work represents an update to 2012 Korean guideline for SSTI. The present guideline was developed by the adaptation method. This clinical guideline provides recommendations for the diagnosis and management of SSTI, including impetigo/ecthyma, purulent skin and soft tissue infection, erysipelas and cellulitis, necrotizing fasciitis, pyomyositis, clostridial myonecrosis, and human/animal bite. This guideline targets community-acquired skin and soft tissue infection occurring among adult patients aged 16 years and older. Diabetic foot infection, surgery-related infection, and infections in immunocompromised patients were not included in this guideline.
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Adulto , Humanos , Celulitis (Flemón) , Enfermedades Transmisibles , Pie Diabético , Diagnóstico , Erisipela , Fascitis , Fascitis Necrotizante , Huésped Inmunocomprometido , Impétigo , Métodos , Piomiositis , Piel , Infecciones de los Tejidos BlandosRESUMEN
No abstract available.
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Femenino , Humanos , Atención Ambulatoria , Urgencias Médicas , Servicios Médicos de Urgencia , Servicio de Urgencia en Hospital , Pacientes Ambulatorios , PielonefritisRESUMEN
Stenotrophomonas maltophilia (S. maltophilia) is a rare, but globally emerging gram-negative multiple-drug-resistant organism usually found in a nosocomial setting in immunocompromised patients. To our best knowledge, computed tomography (CT) features of community-acquired S. maltophilia pneumonia have not been previously reported in an immunocompetent patient. Herein, we presented the CT findings of a previous healthy 56-year-old male with S. maltophilia pneumonia.
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Humanos , Masculino , Persona de Mediana Edad , Huésped Inmunocomprometido , Neumonía , Stenotrophomonas maltophilia , StenotrophomonasRESUMEN
BACKGROUND: From May to July 2015, the Republic of Korea experienced the largest outbreak of Middle East respiratory syndrome (MERS) outside the Arabian Peninsula. A total of 186 patients, including 36 deaths, had been diagnosed with MERS-coronavirus (MERS-CoV) infection as of September 30th, 2015. MATERIALS AND METHODS: We obtained information of patients who were confirmed to have MERS-CoV infection. MERS-CoV infection was diagnosed using real-time reverse-transcriptase polymerase chain reaction assay. RESULTS: The median age of the patients was 55 years (range, 16 to 86). A total of 55.4% of the patients had one or more coexisting medical conditions. The most common symptom was fever (95.2%). At admission, leukopenia (42.6%), thrombocytopenia (46.6%), and elevation of aspartate aminotransferase (42.7%) were observed. Pneumonia was detected in 68.3% of patients at admission and developed in 80.8% during the disease course. Antiviral agents were used for 74.7% of patients. Mechanical ventilation, extracorporeal membrane oxygenation, and convalescent serum were employed for 24.5%, 7.1%, and 3.8% of patients, respectively. Older age, presence of coexisting medical conditions including diabetes or chronic lung disease, presence of dyspnea, hypotension, and leukocytosis at admission, and the use of mechanical ventilation were revealed to be independent predictors of death. CONCLUSION: The clinical features of MERS-CoV infection in the Republic of Korea were similar to those of previous outbreaks in the Middle East. However, the overall mortality rate (20.4%) was lower than that in previous reports. Enhanced surveillance and active management of patients during the outbreak may have resulted in improved outcomes.
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Humanos , Antivirales , Aspartato Aminotransferasas , Infecciones por Coronavirus , Brotes de Enfermedades , Disnea , Oxigenación por Membrana Extracorpórea , Fiebre , Hipotensión , Leucocitosis , Leucopenia , Enfermedades Pulmonares , Coronavirus del Síndrome Respiratorio de Oriente Medio , Medio Oriente , Mortalidad , Neumonía , Reacción en Cadena de la Polimerasa , República de Corea , Respiración Artificial , TrombocitopeniaRESUMEN
BACKGROUND: Automated Mediace Treponema pallidum latex agglutination (TPLA) and Mediace rapid plasma reagin (RPR) assays are used by many laboratories for syphilis diagnosis. This study compared the results of the traditional syphilis screening algorithm and a reverse algorithm using automated Mediace RPR or Mediace TPLA as first-line screening assays in subjects undergoing a health checkup. METHODS: Samples from 24,681 persons were included in this study. We routinely performed Mediace RPR and Mediace TPLA simultaneously. Results were analyzed according to both the traditional algorithm and reverse algorithm. Samples with discordant results on the reverse algorithm (e.g., positive Mediace TPLA, negative Mediace RPR) were tested with Treponema pallidum particle agglutination (TPPA). RESULTS: Among the 24,681 samples, 30 (0.1%) were found positive by traditional screening, and 190 (0.8%) by reverse screening. The identified syphilis rate and overall false-positive rate according to the traditional algorithm were lower than those according to the reverse algorithm (0.07% and 0.05% vs. 0.64% and 0.13%, respectively). A total of 173 discordant samples were tested with TPPA by using the reverse algorithm, of which 140 (80.9%) were TPPA positive. CONCLUSIONS: Despite the increased false-positive results in populations with a low prevalence of syphilis, the reverse algorithm detected 140 samples with treponemal antibody that went undetected by the traditional algorithm. The reverse algorithm using Mediace TPLA as a screening test is more sensitive for the detection of syphilis.