The heme-binding protein Dap1 links iron homeostasis to azole resistance via the P450 protein Erg11 in Candida glabrata

The pathogenic fungus Candida glabrata is relatively resistant to azole antifungals, which target lanosterol 14α-demethylase (Erg11p) in the ergosterol biosynthesis pathway. Our study revealed that C. glabrata exhibits increased azole susceptibility under low-iron conditions. To investigate the molecular basis of this phenomenon, we generated a strain lacking the heme (iron protoporphyrin IX)-binding protein Dap1 in C. glabrata. The Δdap1 mutant displayed growth defects under iron-limited conditions, decreased azole tolerance, decreased production of ergosterol, and increased accumulation of 14α-methylated sterols lanosterol and squalene. All the Δdap1 phenotypes were complemented by wild-type DAP1, but not by DAP1(D91G) , in which a heme-binding site is mutated. Furthermore, azole tolerance of the Δdap1 mutant was rescued by exogenous ergosterol but not by iron supplementation alone. These results suggest that heme binding by Dap1 is crucial for Erg11 activity and ergosterol biosynthesis, thereby being required for azole tolerance. A Dap1-GFP fusion protein predominantly localized to vacuolar membranes and endosomes, and the Δdap1 cells exhibited aberrant vacuole morphologies, suggesting that Dap1 is also involved in the regulation of vacuole structures that could be important for iron storage. Our study demonstrates that Dap1 mediates a functional link between iron homeostasis and azole resistance in C. glabrata.

Interaction of IL-1β and P2X(3) receptor in pathologic masseter muscle pain

The exact mechanism underlying chronic masseter muscle pain, a conspicuous symptom in temporomandibular disorder, remains unclear. We investigated whether expression of P2X3 receptor (P2X3R) is involved in mechanical hyperalgesia after contraction of masseter muscle (CMM). As compared with sham rats, the head-withdrawal threshold (HWT) to mechanical pressure stimulation of masseter muscle (MM) (but not after similar stimulation of facial skin) was significantly lower, and IL-1β level was significantly higher, in CMM rats on day 7 after CMM. The mean percentage of FG-labeled P2X3R-positive neurons was significantly increased in TG following successive IL-1β injections into the MM for 7 days. Successive administration of an IL-1β receptor-antagonist into the MM attenuated the increase of P2X3-IR cells in the TG. ATP release from MM after 300-g pressure stimulation of MM was also significantly enhanced after CMM. Administration into MM of the selective P2X3,2/3 receptor antagonist A-317491 attenuated the decrement of HWT in CMM rats. A significant increase in HWT was also observed at 30 min after A-317491 (60 µg) injection in IL-1β-injected rats. These findings suggest that P2X3R expression associated with enhanced IL-1β expression and ATP release in MM has a possible important role in MM mechanical hyperalgesia after excessive muscular contraction.

Prospective randomized comparison study of piperacillin/tazobactam and meropenem for healthcare-associated pneumonia in Japan

Healthcare-associated pneumonia (HCAP) may have a more severe course than community-acquired pneumonia (CAP); hence, it is more likely to be caused by drug-resistant bacterial pathogens and anaerobes involved in aspiration pneumonia. We compared the efficacy and safety of initial empiric therapy with piperacillin/tazobactam (PIPC/TAZ, 13.5 g/day) with that of meropenem (MEPM, 1.5 g/day) as single broad-spectrum regimens with gram-negative and anaerobic coverage in patients with HCAP in Japan. The clinical cure rate was 75.9 % (22/29 cases) in the PIPC/TAZ group and 64.3 % (18/28 cases) in the MEPM group. The clinical efficacy rate was 87.9 % (29/33 cases) in the PIPC/TAZ group and 74.2 % (23/31 cases) in the MEPM group. The bacteriological eradication rate was 94.4 % (17/18) in the PIPC/TAZ group and 87.5 % (14/16) in the MEPM group. Adverse drug reactions were seen in 22.4 % (11/49 cases) of patients in the PIPC/TAZ group and 17.4 % (8/46 cases) of patients in the MEPM group. Although not statistically different, the PIPC/TAZ group had a slightly higher efficacy rate than the MEPM group. Both treatment regimens are tolerable and might be appropriate to use as initial empiric therapy for HCAP in Japan. To investigate the differences in efficacy profiles of those two regimens, a further confirmatory study with a larger cohort as determined by a power analysis is recommended.

Necrotizing pneumonia due to femoral osteomyelitis caused by community-acquired methicillin-resistant Staphylococcus aureus

A chest X-ray of a young healthy African-American man with acute respiratory failure revealed bilateral multiple nodular shadows in the lungs, while community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) was detected in blood and sputum cultures. Magnetic resonance imaging showed osteomyelitis of the left thigh, and computed tomography revealed bilateral cavitary lesions in the chest, indicating necrotizing pneumonia with pulmonary embolism caused by osteomyelitis as a result of infection with CA-MRSA. CA-MRSA should be suspected as a causative agent of severe community-acquired pneumonia, even in Japan, among patients who belong to communities at high risk of CA-MRSA infection.

Enhancement of antibody production by growth factor addition in perfusion and hollow-fiber culture systems

The effects of the high-molecular-weight growth factors, transferrin and bovine serum albumin (BSA), on antibody production were analyzed quantitatively in continuous hollow-fiber cultivation over a period of 60 days. Transferrin enhanced cell growth but had no significant effect on the specific antibody production rate, whereas BSA significantly enhanced antibody production. The antibody production rate was increased 4- and 14-fold respectively by feeding BSA at 2 and 5 g L(-1) into the EC side of the system (the side connected to the cell-containing outer part of the hollow-fiber unit) compared with the production achieved without BSA. Addition of 5 g L(1) BSA into the IC side of the system (the side connected to the inner part of the hollow-fiber unit) resulted in a 2.5-fold increase in the antibody production rate. The effect of BSA was also analyzed using the perfusion culture system with a separation unit. When fresh medium containing either 2 or 5 g L(-1) BSA was fed into the reactor, both the specific growth rate and specific death rate increased, while the specific antibody production rate was increased 2- and 25-fold, respectively, by feeding BSA at these two concentrations compared with no addition. Comparing the two systems, the increase in the antibody production rate achieved with the hollow-fiber system was threefold greater than that in the perfusion culture system with the same concentration of BSA feeding. (c) 1995 John Wiley & Sons, Inc.

[An adult case of influenza-associated encephalitis successfully treated with high dose intravenous immunoglobulins]

A 73-year-old man was admitted to our hospital with a high fever and left paresis. A rapid diagnosis test was positive for influenza A was positive by rapid diagnosis test and diffusion-weighted MRI imaging of the brain showed a high intensity lesion of the right cerebral peduncle. The patient was therefore diagnosed as having influenza A virus infection complicated with lacunar infarction. In spite of initial treatment with oseltamivir and anticoagulant therapy, he lost consciousness eight hours after admission. The high intensity lesion of the cerebral peduncle enlarged and new lesions in the thalamus, hippocampus and calcarine cortex were detected with brain MRI. Additionally, an electroencephalographic study showed an entire slow wave and as the other causative pathogens of central nerve system infection were not detected, the likely diagnosis was influenza-associated encephalitis. We administered a high dose of intravenous immunoglobulin since the low-grade fever and mild unconscious state had continued in spite of the treatment with methylprednisolone pulse therapy. His consciousness was restored and body temperature became normal immediately. We could confirm the efficacy of our treatment by measurement of IL-6 levels in the serum and cerebrospinal fluid during the entire clinical course. In conclusion, a high dose of intravenous immunoglobulin therapy might be one of the effective treatments for influenza-associated encephalitis.

Multilocus sequence typing of Cryptococcus neoformans in non-HIV associated cryptococcosis in Nagasaki, Japan

Cryptococcosis is primarily caused by two Cryptococcus species, i.e., Cryptococcus neoformans and C. gattii. Both include several genetically diverse subgroups that can be differentiated using various molecular strain typing methods. Since little is known about the molecular epidemiology of the C. neoformans/C. gattii species complex in Japan, we conducted a molecular epidemiological analysis of 35 C. neoformans isolates from non-HIV patients in Nagasaki, Japan and 10 environmental isolates from Thailand. All were analyzed using URA5-restriction fragment length polymorphism (RFLP) and multilocus sequence typing (MLST). Combined sequence data for all isolates were evaluated with the neighbor-joining method. All were found to be serotype A and mating type MATα. Thirty-two of the 35 clinical isolates molecular type VNI, while the three remaining isolates were VNII as determined through the URA5-RFLP method. Thirty-one of the VNI isolates were identified as MLST sequence type (ST) 5, the remaining one was ST 32 and the three VNII isolates were found to be ST 43. All the environmental isolates were identified as molecular type VNI (four MLST ST 5 and six ST 4). Our study shows that C. neoformans isolates in Nagasaki are genetically homogeneous, with most of the isolates being ST 5.

The efficacy and safety of high-dose arbekacin sulfate therapy (once-daily treatment) in patients with MRSA infection

The efficacy and safety of once-daily high-dose arbekacin sulfate therapy for methicillin-resistant Staphylococcus aureus (MRSA) infection were evaluated, with analysis of their relationship to blood drug levels. The study was conducted in patients with pneumonia or sepsis, the cause of which was suspected to be MRSA, who were admitted to the Nagasaki University Hospital or its affiliated hospitals between January 2009 and December 2010. The initial drug dose was set at a level expected to yield the goal peak of 20 μg/ml and a trough level of less than 2 μg/ml, using the Habekacin Therapeutic Drug Monitoring analysis software. Thirteen patients were enrolled: 10 patients had pneumonia and 3 patients had sepsis. Patient mean age was 72.0 years; mean initial drug dose was 269.2 mg. Clinical efficacy at completion of treatment and bacterial eradication-reduction were achieved in 66.7% (6/9) and 62.5% (5/8) of patients, respectively. Incidence of adverse reactions was 38.5% (5/13). In analysis of efficacy in relationship to serum drug levels, the peak drug level was 22.7 ± 5.50 μg/ml, on average, and 15 μg/ml or higher in all 6 responders. Also, in patients with renal dysfunction, it seemed to be essential to ensure a certain peak drug level and to control the trough level appropriately. Although the number of patients was limited, once-daily high-dose arbekacin sulfate therapy may be highly effective, without posing any major safety problems. Further larger-scale studies are needed.

A case of refractory chronic respiratory tract infection due to Pseudomonas aeruginosa successfully controlled by combination of clarithromycin and azithromycin

The prognosis of patients with chronic respiratory tract infections, especially diffuse panbronchiolitis, is remarkably improved by long-term administration of low-dose macrolides. However, in some cases, patients are refractory to macrolide treatment and show a low or no response; therefore, new treatment strategies are required. Here we present a patient refractory to either single low-dose clarithromycin or azithromycin but responded remarkably to the combination usage of both macrolides.

Active surveillance of methicillin-resistant Staphylococcus aureus with the BD GeneOhm MRSA™ assay in a respiratory ward in Nagasaki, Japan

The utility of active surveillance cultures (ASCs) in respiratory wards, that do not have an associated intensive care unit (ICU), and the usefulness of the BD GeneOhm MRSA™ system for rapid detection of methicillin-resistant Staphylococcus aureus (MRSA) have not been previously evaluated in Japan. ASCs using conventional culture methods and the BD GeneOhm MRSA™ assay were conducted in adult inpatients between May 11, 2009 and November 10, 2009 in a respiratory ward, without an associated ICU, in Nagasaki University Hospital. The infection and colonization rates of MRSA acquired in this respiratory ward were both investigated. A total of 159 patients were investigated. Of these, 12 (7.5%) were found positive for MRSA by the BD GeneOhm MRSA™ assay and 9 (5.7%) were found positive by a conventional culture test upon admission. All cases were MRSA-colonized cases and cross-transmission was not found to occur during hospitalization. The BD GeneOhm MRSA™ assay had a sensitivity of 100% and a specificity of 98%. ASCs in our respiratory ward revealed that MRSA was brought in from other sites in some cases, and that current infection control measures in Nagasaki University Hospital are effective. The BD GeneOhm MRSA™ assay was proven to be a useful and rapid detection tool for MRSA.

A case of bronchial aspergillosis caused by Aspergillus udagawae and its mycological features

Aspergillus udagawae and A. fumigatus share similar morphological features but they differ genetically. There is also an important clinical distinction as A. udagawae is less sensitive to amphotericin B than A. fumigatus. We encountered a rare case of bronchial infection due to A. udagawae that was successfully treated with voriconazole. An 82-year-old woman with diabetes mellitus complained of bloody sputum. Bronchoscopy revealed a white plugged region at the origin of the right bronchi B5. Cytological study revealed a clot composed of filamentous fungi and Aspergillus spp. was detected by culture. Molecular analysis revealed that the causative agent was A. udagawae, and voriconazole was used for the treatment. In comparison to A. fumigatus, the A. udagawae strain isolated in this case was less sensitive to amphotericin B, less virulent in immunosuppressed mice, and more sensitive to hydrogen peroxide, features that are almost identical to those of the previously reported isolates of the fungus. We should be aware of the emergence of new Aspergillus species that might pose a clinical threat.

Interleukin-1β causes long-term potentiation deficiency in a mouse model of septic encephalopathy

Sepsis induces multiple organ dysfunction syndrome including septic encephalopathy (SE), which results in cognitive impairment. However, an effective treatment for SE remains unknown. We determined the role of interleukin-1β (IL-1β) in long-term potentiation (LTP) deficiency after SE. At first, endotoxin level in the blood was increased at 24 h after cecum ligation and puncture (CLP) (i.e. SE model). Second, the expression of IL-1β and its receptor in the hippocampus was determined by immunohistochemistry and immunoblotting. The number of Iba1-positive cells and their expression of IL-1β were enhanced by CLP with disruption of the blood brain barrier. Also, Iba1, IL-1β, and occludin protein expressions were consistent with immunohistochemical results. Third, we used an electrophysiological technique and observed the LTP deficiency, a hallmark of learning and memory, in the slices of hippocampus after CLP. Since type 1 interleukin-1 receptors (IL-1R1s) on neuronal cells were increased in the hippocampus, we utilized IL-1R1 antagonist. Pre-incubation with IL-1R1 antagonist for 30 min before recording of field excitatory post-synaptic potentials (fEPSPs) in the hippocampus canceled LTP deficiency after CLP. These results suggest the novel importance of IL-1β in synaptic plasticity deficiency associated with sepsis-induced brain inflammation. In a mouse model of SE, IL-1R1 inhibition is important in protecting synaptic function of the hippocampus after induction of SE.