Properties of Achromobacter xylosoxidans highly resistant to aminoglycoside antibiotics.

We herein discovered a highly resistant clinical isolate of Pseudomonas aeruginosa with MICs to amikacin, gentamicin, and arbekacin of 128 µg/mL or higher in a drug sensitivity survey of 92 strains isolated from the specimens of Yoka hospital patients between January 2009 and October 2010, and Achromobacter xylosoxidans was separated from this P. aeruginosa isolate. The sensitivity of this bacterium to 29 antibiotics was investigated. The MICs of this A. xylosoxidans strain to 9 aminoglycoside antibiotics were: amikacin, gentamicin, arbekacin, streptomycin, kanamycin, neomycin, and spectinomycin, 1,024 µg/mL or ≥ 1,024 µg/mL; netilmicin, 512 µg/mL; and tobramycin, 256 µg/mL. This strain was also resistant to dibekacin. This aminoglycoside antibiotic resistant phenotype is very rare, and we are the first report the emergence of A. xylosoxidans with this characteristic.

Positive Predictive Value of True Bacteremia according to the Number of Positive Culture Sets in Adult Patients.

BACKGROUND: Performing multiple blood culture sets simultaneously is a standard blood culture methodology, although it is often difficult to distinguish true bacteremia from contamination when only one of several blood culture sets is positive. This study clarified the relationship between the number of positive blood culture sets and clinical significance in patients with positive blood culture. METHODS: Patients aged 18 years and over with at least 1 positive blood culture were enrolled. Positive blood culture episodes were categorized from clinical records as true bacteremia, contamination, or unknown clinical significance. The associations among episodes of true bacteremia, isolated bacteria, the number of positive blood culture sets from among the performed sets, and the clinical background of patients were analyzed. RESULTS: Among a total of 407 episodes, 262, 67 and 78 were true bacteremia, contamination and unknown clinical significance, respectively. The positive predictive values (PPVs) of 1 out of 1, 1 out of 2 and 2 out of 2 positive sets in cases of Staphylococcus aureus, were 81.3%, 50% and 100% respectively; those in cases of coagulase-negative Staphylococci were 20.5%, 10.8% and 63.5%, respectively. Almost all cases of Escherichia coli, Pseudomonas aeruginosa, Klebsiella species and Candida species were true bacteremia. The probability of true bacteremia was strongly associated with recent surgery in multivariate analysis (P < 0.05). CONCLUSION: The probability of true bacteremia based on the number of positive culture sets from among the performed sets varies by microorganism. Therefore, PPVs calculated using this method may help physicians distinguish true bacteremia from contamination.

Difference of health-care associated pneumonia between large hospitals and small hospitals in Japan.

OBJECTIVE: Health-care associated pneumonia (HCAP) is a new category of pneumonia. We investigated differences of epidemiology, pathogens, and outcomes between HCAP patients in large hospitals and those in small hospitals. METHODS: This was a retrospective observational study of patients hospitalized with HCAP from December 2009 to March 2010. HCAP was defined according to ATS/IDSA criteria. A large hospital was defined as ≥ 200 beds and a small hospital was <200 beds. RESULTS: Of 117 patients, 61 patients were admitted to large hospitals and 56 patients were admitted to small hospitals. There was a significant difference of HCAP diagnostic criteria between the two groups. The A-DROP severity class was worse in the large hospital group than the small hospital group (P<0.05). Respiratory failure and disturbance of consciousness were more frequent in the large hospital group (P<0.05). The mortality rate was 8.2% in the large hospital group versus 1.8% in the small hospital group. Patients in the very severe A-DROP class had a high mortality rate of 33% in both groups. CONCLUSION: Patients with severe HCAP were more likely to be admitted to large hospitals. Patients in the very severe A-DROP class should receive intensive antibiotic therapy, but not all patients need broad-spectrum therapy.

[Peripheral T-cell lymphoma unspecified with remarkably extensive airspace consolidations and ground-glass opacities of bilateral lung fields].

A 53-year-old man had presented to a nearby hospital with fever, dyspnea and multiple lymphadenopathy. Chest X-ray film and computed tomography had shown expanded airspace consolidations with air broncograms and surrounding ground-glass opacities in bilateral lung fields. Because his respiratory status had gradually worsened, he was transferred to our hospital and placed on the ventilator. Bronchoalveolar lavage were performed, showing abnormal lymphocytes which indicated infiltration of malignant lymphoma. Furthermore, a biopsy of the left inguinal lymph node revealed T-cell lymphoma. We finally diagnosed his pulmonary lesions as involvement of peripheral T-cell lymphoma unspecified in consideration of immunohistochemical estimation. Pulmonary involvement of malignant lymphoma is thought to be relatively uncommon. Therefore, this is considered an extremely rare case showing extensively spreading airspace consolidations and surrounding ground-glass opacities of bilateral lung fields caused by the infiltration of malignant cells along with lymphoid tissues. Because these radiological findings may indicate a severe status of lymphoma, it is necessary to diagnose and treat them immediately. From this point of view, we report this case with useful information concerning differential radiological diagnosis.

Expression of functional leukotriene B4 receptors on human airway smooth muscle cells.

BACKGROUND: Leukotriene B4 (LTB4) increases in induced sputum and exhaled breath condensate in people with asthma. Furthermore, the T(H)2-type immune response and airway hyperresponsiveness induced by ovalbumin sensitization is markedly suppressed in LTB4 receptor (BLT) 1 null mice. These studies suggest that LTB4 may contribute to asthma pathophysiology. However, the direct effects of LTB4 on human airway smooth muscle (ASM) have not been studied. OBJECTIVES: We sought to determine the expression of LTB4 receptors on human ASM and its functional role in mediating responses of human ASM cells, and the effect of LTB4 on these cells. METHODS: Immunohistochemistry, RT-PCR, Western blotting, and flow cytometry were used to determine the expression of LTB4 receptors. To determine the effect of LTB4 on human ASM cells, cell proliferation was assessed by counting cells, and chemokinesis was assessed by gold particle phagokinesis assay. RESULTS: We confirmed expression of both BLT1 and BLT2 in human ASM cells in bronchial tissue and in cell culture. LTB4 markedly induced cyclin D1 expression, proliferation, and chemokinesis of human ASM cells. LTB4 also induced phosphorylation of both p42/p44 mitogen-activated protein kinase (MAPK) and downstream PI3 kinase effector, Akt1. However, we observed no induction of c-Jun N-terminal kinase or p38 MAPK. Notably, LTB4-induced migration and proliferation of ASM cells were inhibited by the BLT1 specific antagonist, U75302, and by inhibitors of p42/p44 MAPK phosphorylation (U1026), and PI3 kinase (LY294002). CONCLUSIONS: These observations are the first to suggest a role for a LTB4-BLT1 signaling axis in ASM responses that may contribute to the pathogenesis of airway remodeling in asthma.

[Acute bird-related hypersensitivity pneumonitis: radiological findings in a case in the early phase after onset].

A 71-year-old woman was admitted to our hospital four times because of high fever and dyspnea from September to November in 2007. We treated her with antibiotics on her first two admissions. HOwever, we suspected hypersensitivity pneumonitis on the third admission because she suffered from fever and dyspnea soon after she had been discharged and returned home. She recovered only with the oxygen therapy on the last two admissions. Computed tomography of the chest showed early phase localized consolidation but changed to ground-glass opacities spreading over the entire lung field later during her third and fourth admissions. Bronchial alveolar lavage showed increases in total cell count, lymphocytes and IgA of pigeon-dropping extracts' and budgerigar-dropping extracts. TBLB showed epithelioid cell granulomas without caseous necrosis and alveolar septal inflammation. Inhalation challenge test using freeze-dried pigeon-dropping extracts was positive, therefore we finally established a diagnosis of acute bird related hypersensitivity pneumonitis. This is apparently the first report of acute bird-related hypersensitivity pneumonitis showing localized consolidation initially and later changing to diffuse ground-glass opacities. These radiological observations are significant in considering the onset and the progression of this disease.

[Case of an HTLV-1 carrier complicated with chronic pulmonary histoplasmosis].

A 58-year-old man was admitted with complaints of pain in the right upper right side of the chest. Chest radiography and computed tomography (CT) revealed a cavitary lesion in the right upper lobe. A CT-guided percutaneous lung biopsy and transbronchial lung biopsy of this lesion did not yield a definitive diagnosis; therefore, we performed video assisted thoracic surgery (VATS). We also investigated various types of mycosis because he had several records of overseas travel. At a later day, the histoplasma immunodiffusion test showed positive results. We finally diagnosed pulmonary histoplasmosis based on the clinical course, CT and radiographic images and serological tests. Voriconazole improved the patient's subjective symptoms and laboratory findings. A positive reaction was obtained for anti-human T-cell leukemia virus type 1 (HTLV-1) antibody and the HTLV-1 carrier, confirming his immunodeficiency disorder. We raised the possibility that the development of pulmonary histoplasmosis might be associated with the HTLV-1 carrier.