• Tuberculosis and Respiratory Diseases
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• 제72권5호
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• pp.452-456
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• 2012

Disseminated Mycobacterium avium complex (MAC) infection can occur in immunocompromised patients, and rarely in immunocompetent subjects. Due to the extensive distribution of the disease, clinical presentation of disseminated MAC may mimic malignancies, and thorough examinations are required in order to make accurate diagnosis. We report a case of disseminated Mycobacterium intracellulare disease in an immunocompetent patient, which involved the lung, lymph nodes, spleen, and multiple bones. F-18 fluorodeoxyglucose positron-emission tomography imaging showed multiple hypermetabolic lesions, which are suggestive of typical hematogenous metastasis. However, there was no evidence of malignancy in serial biopsies, and M. intracellulare was repeatedly cultured from respiratory specimens and bones. Herein, we should know that disseminated infection can occur in the immunocompetent subjects, and it can mimic malignancies.

• Korean Journal of Radiology
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• 제25권5호
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• pp.481-492
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• 2024

Objective: To evaluate the clinical and imaging characteristics of SARS-CoV-2 breakthrough infection in hospitalized immunocompromised patients in comparison with immunocompetent patients. Materials and Methods: This retrospective study analyzed consecutive adult patients hospitalized for COVID-19 who received at least one dose of the SARS-CoV-2 vaccine at two academic medical centers between June 2021 and December 2022. Immunocompromised patients (with active solid organ cancer, active hematologic cancer, active immune-mediated inflammatory disease, status post solid organ transplantation, or acquired immune deficiency syndrome) were compared with immunocompetent patients. Multivariable logistic regression analysis was performed to evaluate the effect of immune status on severe clinical outcomes (in-hospital death, mechanical ventilation, or intensive care unit admission), severe radiologic pneumonia (≥ 25% of lung involvement), and typical CT pneumonia. Results: Of 2218 patients (mean age, 69.5 ± 16.1 years), 274 (12.4%), and 1944 (87.6%) were immunocompromised an immunocompetent, respectively. Patients with active solid organ cancer and patients status post solid organ transplantation had significantly higher risks for severe clinical outcomes (adjusted odds ratio = 1.58 [95% confidence interval {CI}, 1.01-2.47], P = 0.042; and 3.12 [95% CI, 1.47-6.60], P = 0.003, respectively). Patient status post solid organ transplantation and patients with active hematologic cancer were associated with increased risks for severe pneumonia based on chest radiographs (2.96 [95% CI, 1.54-5.67], P = 0.001; and 2.87 [95% CI, 1.50-5.49], P = 0.001, respectively) and for typical CT pneumonia (9.03 [95% CI, 2.49-32.66], P < 0.001; and 4.18 [95% CI, 1.70-10.25], P = 0.002, respectively). Conclusion: Immunocompromised patients with COVID-19 breakthrough infection showed an increased risk of severe clinical outcome, severe pneumonia based on chest radiographs, and typical CT pneumonia. In particular, patients status post solid organ transplantation was specifically found to be associated with a higher risk of all three outcomes than hospitalized immunocompetent patients.

• Mycobiology
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• 제37권3호
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• pp.161-170
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• 2009

Cryptococcus neoformans is a basidiomycete human fungal pathogen that causes meningoencephalitis in both immunocompromised and immunocompetent individuals. The ability to sense and respond to diverse extracellular signals is essential for the pathogen to infect and cause disease in the host. Four major stress-activated signaling (SAS) pathways have been characterized in C. neoformans, including the HOG (high osmolarity glycerol response), PKC/Mpk1 MAPK (mitogen-activated protein kinase), calcium-dependent calcineurin, and RAS signaling pathways. The HOG pathway in C. neoformans not only controls responses to diverse environmental stresses, including osmotic shock, UV irradiation, oxidative stress, heavy metal stress, antifungal drugs, toxic metabolites, and high temperature, but also regulates ergosterol biosynthesis. The PKC(protein kinase C)/Mpk1 pathway in C. neoformans is involved in a variety of stress responses, including osmotic, oxidative, and nitrosative stresses and breaches of cell wall integrity. The $Ca^{2+}$/calmodulin- and Ras-signaling pathways also play critical roles in adaptation to certain environmental stresses, such as high temperature and sexual differentiation. Perturbation of the SAS pathways not only impairs the ability of C. neoformans to resist a variety of environmental stresses during host infection, but also affects production of virulence factors, such as capsule and melanin. A drug(s) capable of targeting signaling components of the SAS pathway will be effective for treatment of cryptococcosis.

• Parasites, Hosts and Diseases
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• 제40권4호
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• pp.181-186
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• 2002

To examine the fate of Strongyloides venezuelensis, Mongolian gerbils (Meriones unguicalatus) were orally infected with 1,000 $L_{3}$ larvae per animal. Altogether, 50 gerbils divided into 5 groups of 10 each were monitored for a period of 570 days to document the kinetics of faecal egg output, adults worm population, morphological development, fecundity, and hematological changes including peripheral blood eosinophilia. This study chronicled a life long parasitism of S. venezuelensis in the gerbil host, and showed that S. venezuelensis infection was quite stable throughout the course of infection and the worms maintained their normal development as evidenced by their body dimension. A progressive loss of body condition of the infected gerbils was observed as the level of infection advanced. However, no detectable pathological changes were observed in the gastrointestinal tract. The present findings indicate that an immunocompetent host, such as the Mongolian gerbil, can serve as a life long carrier model of S. venezuelensis if the worms are not expelled within 570 days after infection.

• Clinical and Experimental Pediatrics
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• 제53권5호
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• pp.666-668
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• 2010

Pyogenic liver abscesses are rare in children. In pediatric patients, altered host defences seem to play an important role. However, pyogenic liver abscess also occurs in healthy children. We experienced a case of pyogenic liver abscess in a healthy immunocompetent 10-year-old-girl. The patient presented two distinct abscesses: one subphrenic and the other intrahepatic. The intrahepatic abscess resolved with percutaneous drainage and 3 weeks of parenteral antibiotic therapy but the subphrenic abscess which could not be drained needed prolonged parenteral antibiotic therapy in addition to oral antibiotic therapy. We performed follow-up serial CT scan of the abscess cavity to decide on the duration of antibiotic therapy. Here we present this case with a brief review of the literature.

• Tuberculosis and Respiratory Diseases
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• 제69권1호
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• pp.39-42
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• 2010

Mycobacterium massiliense is newly identified rapid-growing nontuberculous mycobacterium, but there are no reports of this mycobacterium species being the cause of human illness. We describe one case of Mycobacterium massiliense infection presenting as antibiotic-resistant acute pneumonia that resulted in surgical treatment.

• Journal of Chest Surgery
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• 제33권7호
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• pp.601-604
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• 2000

방선균증은 혐기성 그람 양성균인 Actinomyces israelii의 감염에 의한 만성 육야종성 질환으로 안면부, 폐, 목부에 주로 발생하며 농양, 누공 두터운 반흔의 형성을 특징으로 한다. 식도 방선균증은 매우 드물어 전세계적으로 단지 몇례 보고되어 있으며, 그 대부분이 후천성 면역결핍증 환자에서의 발병이다. 염산의 오연으로 인한 식도협착이 발생한 58세의 여자에서 식도 스텐트 삽입후 흉통, 연하장애, 연하통이 발생하였고 이에 대한 식도절제술후 병리조직학적으로 식도 방선균증으로 확진된 증례를 보고한다.

• Tuberculosis and Respiratory Diseases
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• 제73권5호
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• pp.278-281
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• 2012

A 47-year old man visited our hospital because of purulent sputum for 3 months. Chest X-ray showed destruction of both the upper lungs, and bronchoscopy revealed inflammatory change with whitish plaque on the left main bronchus through upper division of the left upper lobe. Tracheobronchial aspergillosis (TBA) was finally diagnosed as a result of histologic and microbiologic examination. However, he went abroad without medication before the diagnosis was made and visited again 10 months later. Follow-up bronchoscopy showed complete regression of the previously noted endobronchial lesion. We describe this case to consider the role of antifungal treatment in immunocompetent hosts, as well as to discuss a rare condition; TBA resolved spontaneously.

• Tuberculosis and Respiratory Diseases
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• 제47권5호
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• pp.697-703
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• 1999

Mycobacterium celatum is a recently described nontuberculous mycobacterium. Even though pulmonary or lymphatic infection cases were reported previously in human, the clinical significance of the infection with M. celatum is not yet understood completely. Mast infections with this species occurred in the patients with suppressed cell-mediated immunity such as AIDS, and there are only a few cases of pulmonary infection with M. celatum in immunocompetent adults or infants in the world. In Korea, mycobacterial pulmonary infection is a major problem of respiratory disease but, there has been no pulmonary infection with M. celatum reported. We report, to our knowledge, the first Korean case of pulmonary infection with M. celatum, which was identified by rpoB genomic sequencing.

• Parasites, Hosts and Diseases
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• 제37권1호
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• pp.21-26
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• 1999

The growth and development of Gymnophalloides seoi were studied in C3H/HeN mice and effects of immunosuppression of the host on the worm development were observed. Two hundred metacercariae of G. seoi were orally administered to each mouse, and worms were recovered on days 1, 3, 5, 7, 14 and 21 post-infection (PI). The worm recovery rate was significantly higher in immunosuppressed (ImSP) mice than in immunocompetent (ImCT) mice except on days 1 and 3 PI. The worms attained sexual maturity by day 3 PI with eggs in the uterus, and worm dimensions and the number of uterine eggs continuously increased until day 14 PI in ImSP mice. Worms recovered from ImSP mice were significantly larger in size than those from ImCT mice on days 1 and 3 PI, and the number of uterine eggs was significantly larger in ImSP mice on days 5 and 7 PI. Genital organs such as the ovary, testes, and vitellaria, that were already developed in the metacercarial stage. grew a little in size until day 14 PI. The results show that the C3H/HeN mouse is, though not excellent, a suitable laboratory host for G. seoi.