False-positive for SARS-CoV-2 antigen test in a man with acute HIV infection.

Although rapid antigen tests for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is convenient, some articles have demonstrated their low sensitivity indicating false-negative results should always be considered. Here, we raise the issue of false-positive on rapid antigen tests for SARS-CoV-2 with the first case of acute HIV infection who repeatedly positive for the rapid antigen test. A 39-year-old man was admitted to our hospital complaining of high-grade fever, dry cough, general fatigue, and anorexia. The rapid antigen test performed on a nasopharyngeal swab sample was positive, therefore the patient was separated in an isolated room apart from the COVID-19 ward while awaiting the confirmatory RT-PCR result. However, the RT-PCR for SARS-CoV-2 performed on nasopharyngeal swabs was repeatedly negative (three times), while the antigen test was repeatedly positive (three times in total). This patient was eventually diagnosed with acute human immunodeficiency virus (HIV) infection based on a high titer of HIV-RNA and absence of plasma HIV-1/2 antibodies. Physicians should consider the possibility of false-positive results in addition to false-negative results when using a rapid antigen test for SARS-CoV-2, and keep in mind that nucleic acid amplification tests are needed to confirm the diagnosis.

[Two Cases of Lung Stage â ¢Squamous Cell Carcinoma Treated with Carboplatin (CBDCA)plus Nab-Paclitaxel(Nab-PTX)].

Case 1: 83 years old man. For left upper lobe lungs squamous cell carcinoma infiltrating left main pulmonary artery. After 2 courses went of carboplatin(CBDCA)(AUC: 6)+weekly nab-paclitaxel(nab-PTX)(AUC: 6)+, left upper lobectomy and ND2 lymph nodes dissection. Tumor disappeared in pathology and diagnosed of Ef. 3. Case 2: 81 years old man. Right upper lobe lungs squamous cell carcinoma in #4R lymph node metastasis with the superior vena cava invasion. After 2 courses went of CBDCA(AUC: 6)+weekly nab-PTX(100mg/m2), left upper lobectomy and ND2 lymph nodes dissection. Tumor disappeared in pathology and diagnosed of Ef. 3. Nab-PTX may be considered a preoperative chemotherapeutic agent of choice for squamous cell carcinoma.

Hepatocyte growth factor levels in Legionella pneumonia: a retrospective study.

BACKGROUND: Hepatocyte growth factor (HGF) is known to be involved in the resolution of pulmonary inflammation and repair of acute lung injury. Legionella pneumonia is sometimes complicated by acute lung injury. Our study aimed to determine the role of serum HGF levels in Legionella pneumonia. METHODS: Sera from patients with Legionella pneumonia (42 cases), other bacterial pneumonia (33 cases), pulmonary tuberculosis (19 cases), and normal controls (29 cases) were collected. The serum HGF levels for each serum sample were determined by sandwich ELISA. Clinical and laboratory data were collected by reviewing the medical charts. RESULTS: Serum HGF levels were higher in patients with Legionella pneumonia than in those with other bacterial pneumonia, pulmonary tuberculosis, and controls. The HGF levels were compared with white blood cell counts, C-reactive protein, Alanine amino-transferase, and lactate dehydrogenase (LDH). The HGF levels were correlated to serum LDH levels. Moreover, serum HGF levels were significantly higher in non-survivors than in survivors. CONCLUSIONS: HGF levels increased in severer pneumonia caused by Legionella, suggesting that HGF might play a significant role in the Legionella pneumonia.

Legionella pneumonia caused by Legionella pneumophila serogroup 2: second case report in Japan.

A 56-year-old man with a 3-day history of a chilly sensation and general fatigue presented to a hospital in his neighborhood. He was diagnosed as having pneumonia and immediately treated with intravenous ceftriaxone sodium, but his respiratory condition deteriorated and he developed symptoms of restlessness. Although Legionella urinary antigen detection tests were negative, his clinical course suggested Legionella pneumonia. After his treatment was changed to intravenous ciprofloxacin and oral clarithromycin, his general condition gradually improved. Later, Legionella pneumophila serogroup 2 was isolated from a bronchoalveolar lavage specimen. This was considered to be the causative organism. In our literature search, this was only the second case of Legionella pneumonia caused by Legionella pneumophila serogroup 2 in Japan.

[A-DROP system might result in underestimation of severity of cases with Legionnaires' disease].

Fifteen cases of legionella pneumonia experienced in our department or associated hospital were included in this study. Each case was classified with the A-DROP system of the Japanese Respiratory Society Guidelines, and guidelines from the Infectious Diseases Society of America (IDSA) (1998) and then we compared the severity of the cases of pneumonia. Although 10 cases were classified as intermediate, 3 as severe, and 2 as extremely severe with the A-DROP system, most cases were classified as severe according to the IDSA guidelines. Among 5 fatal cases, three were ranked as intermediate with the A-DROP system. However all the fatal cases were ranked as severe in the IDSA guidelines. This study suggested that the A-DROP system might underestimate the severity of pneumonia in cases with legionella pneumonia.

Legionella pneumophila infection induces programmed cell death, caspase activation, and release of high-mobility group box 1 protein in A549 alveolar epithelial cells: inhibition by methyl prednisolone.

BACKGROUND: Legionella pneumophila pneumonia often exacerbates acute lung injury (ALI) and acute respiratory distress syndrome (ARDS). Apoptosis of alveolar epithelial cells is considered to play an important role in the pathogenesis of ALI and ARDS. In this study, we investigated the precise mechanism by which A549 alveolar epithelial cells induced by L. pneumophila undergo apoptosis. We also studied the effect of methyl prednisolone on apoptosis in these cells. METHODS: Nuclear deoxyribonucleic acid (DNA) fragmentation and caspase activation in L. pneumophila-infected A549 alveolar epithelial cells were assessed using the terminal deoxyribonucleotidyl transferase-mediated triphosphate (dUTP)-biotin nick end labeling method (TUNEL method) and colorimetric caspase activity assays. The virulent L. pneumophila strain AA100jm and the avirulent dotO mutant were used and compared in this study. In addition, we investigated whether methyl prednisolone has any influence on nuclear DNA fragmentation and caspase activation in A549 alveolar epithelial cells infected with L. pneumophila. RESULTS: The virulent strain of L. pneumophila grew within A549 alveolar epithelial cells and induced subsequent cell death in a dose-dependent manner. The avirulent strain dotO mutant showed no such effect. The virulent strains of L. pneumophila induced DNA fragmentation (shown by TUNEL staining) and activation of caspases 3, 8, 9, and 1 in A549 cells, while the avirulent strain did not. High-mobility group box 1 (HMGB1) protein was released from A549 cells infected with virulent Legionella. Methyl prednisolone (53.4 muM) did not influence the intracellular growth of L. pneumophila within alveolar epithelial cells, but affected DNA fragmentation and caspase activation of infected A549 cells. CONCLUSION: Infection of A549 alveolar epithelial cells with L. pneumophila caused programmed cell death, activation of various caspases, and release of HMGB1. The dot/icm system, a major virulence factor of L. pneumophila, is involved in the effects we measured in alveolar epithelial cells. Methyl prednisolone may modulate the interaction of Legionella and these cells.

Detection of Legionella pneumophila serogroup 1 antigen in respiratory samples using an immunochromatographic membrane test.

The immunochromatographic membrane test (ICT) efficacy of Legionella antigen detection (Binax Now Legionella) was evaluated using respiratory samples, including bronchial washings (44 cases) and sputum (128 cases), from suspected Legionella pneumonia patients. The ICT results using respiratory samples agreed well with isolation of L. pneumophila SG1 and ICT using urines.

Necrotizing fasciitis caused by Pseudomonas aeruginosa.

An 85-year-old man patient was admitted to the hospital complaining of fever and bilateral leg pain with swelling and erythema. A laboratory investigation revealed leukocytopenia, thus suggesting sepsis. Gram negative rods were detected in the specimen from the affected skin and empiric antibacterial therapy was initiated. The following day, his symptoms worsened and Pseudomonas aeruginosa was isolated from the blood culture and the skin specimen. Magnetic resonance imaging (MRI) did not show the typical characteristics of necrotizing fasciitis. In spite of intensive medical treatment, the patient's condition became critical, and on day 10 after admission, he died of multiple organ failure. An autopsy revealed necrotizing fasciitis due to P. aeruginosa. This is a rare case and its clinical presentation was atypical. The clinical diagnosis of this infection may be difficult, and therefore such cases warrant the careful attention of physicians.

Mechanisms of Legionella pneumophila-induced interleukin-8 expression in human lung epithelial cells.

BACKGROUND: Legionella pneumophila is a facultative intracellular bacterium, capable of replicating within the phagosomes of macrophages and monocytes, but little is known about its interaction with human lung epithelial cells. We investigated the effect of L. pneumophila on the expression of interleukin-8 (IL-8) in human A549 alveolar and NCI-H292 tracheal epithelial cell lines. RESULTS: Infection of L. pneumophila strain, but not heat-killed strain, resulted in upregulation of IL-8. IL-8 mRNA expression was induced immediately after the infection and its signal became gradually stronger until 24 h after infection. On the other hand, IL-8 expression in A549 cells infected with L. pneumophila lacking a functional type IV secretion system was transient. The IL-8 expression was slightly induced at 16 h and increased at 24 h after infection with flagellin-deficient Legionella. Activation of the IL-8 promoter by L. pneumophila infection occurred through the action of nuclear factor-kappaB (NF-kappaB). Transfection of dominant negative mutants of NF-kappaB-inducing kinase, IkappaB kinase and IkappaB inhibited L. pneumophila-mediated activation of IL-8 promoter. Treatment with hsp90 inhibitor suppressed L. pneumophila-induced IL-8 mRNA due to deactivation of NF-kappaB. CONCLUSION: Collectively, these results suggest that L. pneumophila induces activation of NF-kappaB through an intracellular signaling pathway that involves NF-kappaB-inducing kinase and IkappaB kinase, leading to IL-8 gene transcription, and that hsp90 acts as a crucial regulator in L. pneumophila-induced IL-8 expression, presumably contributing to immune response in L. pneumophila. The presence of flagellin and a type IV secretion system are critical for Legionella to induce IL-8 expression in lung epithelial cells.

Intravenous ciprofloxacin versus erythromycin in the treatment of Legionella pneumonia.

BACKGROUND: Erythromycin (EM) and rifampicin (RFP) have mainly been used to treat patients with Legionella pneumonia. Since intravenous ciprofloxacin (CPFX) became available in Japan from 2000, many reports have been published detailing successful treatment of Legionella pneumonia with CPFX. In this study, we compared the evolution of patients with Legionella pneumonia treated with CPFX to those treated with EM. METHODS: The study included nine patients treated with CPFX and eighteen patients treated with EM. Diagnosis of these patients was made by culture, PCR, urinary antigen assay or a serological method. A comparison was made of the patients' characteristics, severity of pneumonia, efficacy of each agent and the clinical course. RESULTS: No significant differences were observed between the two groups, in regard to age, gender, underlying disease or severity of pneumonia. In addition, the period of time from onset of the disease until appropriate therapy did not differ significantly between the two groups. In the CPFX group, all of the patients were cured and in the EM group 16 out of the 18 patients were cured. Although there were no significant differences, the time to apyrexia, normalization of leukocytosis and a 50% decrease in C-reactive protein (CRP) occurred within a relatively shorter time frame in the CPFX group than in the EM group (3.5 versus 4 days, 4 versus 5.2 days, and 2.9 versus 10.3 days, respectively). And, the duration of antibiotic treatment in the CPFX group was significantly shorter than in the EM group. CONCLUSION: CPFX was as effective as erythromycin in the treatment of Legionella pneumonia. The effects of treatment may appear relatively earlier and the duration of treatment was significantly shorter in patients treated with CPFX therapy than with EM therapy.

Interferon-gamma reverses the evasion of Birc1e/Naip5 gene mediated murine macrophage immunity by Legionella pneumophila mutant lacking flagellin.

Legionella pneumophila is the etiologic agent of Legionnaires' disease. This bacterium contains a single monopolar flagellum, of which the FlaA subunit is a major protein constituent. The murine macrophage resistance against this bacterium is controlled by the Birc1e/Naip5 gene, which belongs to the NOD family. We evaluated the intracellular growth of the flaA mutant bacteria as well as another aflagellated fliA mutant, within bone marrow-derived macrophages from mice with an intact (C57BL/6, BALB/c) or mutated (A/J) Birc1e/Naip5 gene. The flaA mutant L. pneumophila multiplied within C57BL/6 and BALB/c macrophages while the wild-type strain did not. Cell viability was not impaired until 3 days after infection when the flaA mutant bacteria replicated 10(2-3)-fold in macrophages, implying that L. pneumophila inhibited host cell death during the early phase of intracellular replication. The addition of recombinant interferon-gamma (IFN-gamma) to the infected macrophages restricted replication of the flaA mutant within macrophages; these treated cells also showed enhanced nitric oxide production, although inhibition of nitric oxide production did not affect the IFN-gamma induced inhibition of Legionella replication. These findings suggested that IFN-gamma activated macrophages to restrict the intracellular growth of the L. pneumophila flaA mutant by a NO independent pathway.

In vitro activity of sitafloxacin against clinical strains of Streptococcus pneumoniae with defined amino acid substitutions in QRDRs of gyrase A and topoisomerase IV.

OBJECTIVES: Fluoroquinolone-resistant Streptococcus pneumoniae are increasing worldwide rapidly. In vitro activities of sitafloxacin were evaluated against clinical isolates of S. pneumoniae resistant to levofloxacin (MIC of levofloxacin > or = 4 mg/L), which were characterized genetically. METHODS: The quinolone resistance determining regions (QRDRs) of gyrA, gyrB, parC and parE of these strains were analysed by PCR-based sequencing. MICs of sitafloxacin and other quinolones were determined by a microdilution broth method. RESULTS: All 18 strains had at least one amino acid substitution in the QRDRs of GyrA and ParC, which included Ser-81-->Tyr/Phe and Glu-85-->Lys in GyrA and Ser-79-->Phe/Ile/Tyr, Asp-83-->Tyr, Asn-91-->Asp, Ser-107-->Phe, Lys-137-->Asn and Ala-142-->Ser in ParC. Most isolates had Asp-435-->Asn/Ile-460-->Val/Ala-596-->Thr substitutions in ParE, while no amino acid substitution in GyrB was noted in all isolates. Ten isolates for which levofloxacin MICs were 16 or 32 mg/L had multiple mutations in both GyrA and ParC. The MIC80 value of sitafloxacin for levofloxacin-resistant isolates was 0.25 mg/L. The range of MICs of sitafloxacin for isolates resistant to levofloxacin (MIC 4-32 mg/L) was 0.016-0.5 mg/L. CONCLUSIONS: These findings warrant further studies to evaluate the usefulness of sitafloxacin in the treatment of levofloxacin-resistant S. pneumoniae infection.

Limited contribution of Toll-like receptor 2 and 4 to the host response to a fungal infectious pathogen, Cryptococcus neoformans.

The present study was designed to elucidate the role of Toll-like receptor (TLR) 2 and TLR4 in the host response to Cryptococcus neoformans. Both TLR2 knockout (KO) and TLR4KO mice produced interleukin-1beta (IL-1beta), IL-6, IL-12p40 and tumor necrosis factor-alpha (TNF-alpha) in sera and cleared this fungal pathogen from infected lungs at a comparable level to control littermate (LM) mice. Synthesis of these cytokines was not significantly different in the lungs of these KO mice and LM mice, although IL-1beta, IL-6 and IL-12p40 tended to be lower in TLR2KO, but not TLR4KO, mice than in controls. In addition, there was no significant reduction detected in the synthesis of IL-12 and TNF-alpha by bone marrow-derived dendritic cells from TLR2KO and TLR4KO mice upon stimulation with live yeast cells. Finally, HEK293 cells expressing either TLR2/dectin-1 or TLR4/MD2/CD14 did not respond to C. neoformans in the activation of nuclear factor kappa B (NFkappaB) detected by a luciferase assay. Our results suggest that TLR2 and TLR4 do not or only marginally contribute to the host and cellular response to this pathogen.

In vitro activity of pazufloxacin, tosufloxacin and other quinolones against Legionella species.

OBJECTIVES: The activities of pazufloxacin and tosufloxacin against Legionella spp. were evaluated in vitro and compared with those of other quinolones, macrolides and azithromycin. METHODS: The conventional MICs were determined by the microbroth dilution method. Intracellular activities of drugs were evaluated by a cfu count. The minimal extracellular concentration inhibiting intracellular growth of bacteria (MIEC) was determined by a colorimetric cytopathic assay. RESULTS: MICs of pazuloxacin and tosufloxacin at which 90% (MIC90) of isolates are inhibited in 76 different Legionella spp. strains (38 ATCC strains and 38 clinical isolates) were 0.032 and 0.016 mg/L, whereas the MIC90s of levofloxacin, ciprofloxacin, garenoxacin, erythromycin, clarithromycin and azithromycin were 0.032, 0.032, 0.032, 2.0, 0.125 and 2.0 mg/L, respectively. Pazufloxacin and tosufloxacin at 4x MIC inhibited intracellular growth of Legionella pneumophila SG1 (80-045 strain), as did other quinolones, clarithromycin and azithromycin, whereas erythromycin at 4x MIC did not. MIECs of pazufloxacin, tosufloxacin, levofloxacin, ciprofloxacin and garenoxacin for the strain were 0.063, 0.004, 0.016, 0.032 and 0.008 mg/L respectively, which were superior to those of macrolides and azithromycin. Pazufloxacin showed potent activity against three additional clinical isolates of L. pneumophila SG1, one clinical isolate each of L. pneumophila SG3 and SG5, as well as Legionella micdadei, Legionella dumoffii and Legionella longbeachae SG1. CONCLUSIONS: Pazufloxacin and tosufloxacin, as well as other quinolones, were more potent than macrolides and an azalide. Present data warrant further study on the efficacy of these drugs in the treatment of Legionella infections.

Differential roles of Toll-like receptors 2 and 4 in in vitro responses of macrophages to Legionella pneumophila.

The role of Toll-like receptors (TLRs) in innate immunity to Legionella pneumophila, a gram-negative facultative intracellular bacterium, was studied by using bone marrow-derived macrophages and dendritic cells from TLR2-deficient (TLR2(-/-)), TLR4(-/-), and wild-type (WT) littermate (C57BL/6 x 129Sv) mice. Intracellular growth of L. pneumophila was enhanced within TLR2(-/-) macrophages compared to WT and TLR4(-/-) macrophages. There was no difference in the bacterial growth within dendritic cells from WT and TLR-deficient mice. Production of interleukin-12p40 (IL-12p40) and IL-10 after infection with L. pneumophila was attenuated in TLR2(-/-) macrophages compared to WT and TLR4(-/-) macrophages. Induction of IL-12p40, IL-10, and tumor necrosis factor alpha secretion from macrophages by the L. pneumophila dotO mutant, which cannot multiply within macrophages, and heat-killed bacteria, was similar to that caused by a viable virulent strain. There was no difference between the WT and its mutants in susceptibility to the cytopathic effect of bacteria. An L. pneumophila sonicated lysate induced IL-12p40 production by macrophages, but that of TLR2(-/-) macrophages was significantly lower than those of WT and TLR4(-/-) macrophages. Treatment of L. pneumophila sonicated lysate with proteinase K and heating did not abolish TLR2-dependent IL-12p40 production. Our results show that TLR2, but not TLR4, is involved in murine innate immunity against L. pneumophila, although other TLRs may also contribute to innate immunity against this organism.

[A case of disseminated aspergillosis with smoldering adult T-cell leukemia].

The patient was 39-year-old male who had been administrated 20 mg of prednisolone for control of chronic eosinophilic pneumonia. He consulted the hospital with fever, headache and gait disturbance. The laboratory data of peripheral blood revealed a smoldering adult T cell leukemia. Computed tomogram of the chest and MRI of the brain revealed a mass in the right middle lobe of the lung and a brain abscess in the left hemisphere respectively. Biopsied specimens from the lung and brain abscess showed an Aspergillus like fungus. In spite of placement of an Ommaya reservoir for administration of AMPH-B and control of intracranial pressure, he died. During the course, specific antigen and specific gene were not detected in the peripheral blood, and no viable organism was isolated from the specimens. Post mortem examination revealed multiple nodular lesions in the lung, parietal pleura, liver, heart and kidney. After autopsy, disseminated aspergillosis was confirmed through a tissue examination using nested PCR for Aspergillus DNA. In this case, we think that viable fungi could endure in the tissue while circulating Aspergillus markers remained undetectable.