Pharmacokinetics, safety, and efficacy of 20% subcutaneous immunoglobulin (Ig20Gly) administered weekly or every 2 weeks in Japanese patients with primary immunodeficiency diseases: a phase 3, open-label study

This phase 3, open-label, multidose study (NCT04346108) evaluated the pharmacokinetics, safety, tolerability, and efficacy of immunoglobulin subcutaneous (human) 20% solution (Ig20Gly) administered weekly and every 2 weeks in Japanese patients with primary immunodeficiency diseases (PIDs). The study was conducted at eight study sites in Japan and enrolled patients aged ≥2 years with PIDs treated using a stable intravenous immunoglobulin dose for ≥3 months prior to the study. Patients received intravenous immunoglobulin every 3 or 4 weeks at pre-study dose (200-600 mg/kg) for 13 weeks (Epoch 1), subcutaneous Ig20Gly (50-200 mg/kg) once weekly for 24 weeks (Epoch 2), and Ig20Gly (100-400 mg/kg) every 2 weeks for 12 weeks (Epoch 3). The primary endpoint was serum total immunoglobulin G (IgG) trough levels during Epochs 2 and 3. Overall, 17 patients were enrolled (median [range] age: 24 [5-69] years; 59% male) and participated in Epochs 1 and 2; seven patients entered Epoch 3. Serum total IgG trough levels were maintained at >8 g/l: geometric means (95% confidence intervals) at the end of Epochs 2 and 3 were 8.56 (8.03-9.12) g/l and 8.39 (7.89-8.91) g/l, respectively. Related treatment-emergent adverse events were all mild in severity; the most common treatment-emergent adverse events (excluding infections) in Epochs 2 and 3 were injection site swelling (24%) and injection site erythema (18%). This is the first trial to demonstrate the efficacy and favourable safety profile of 20% subcutaneous immunoglobulin administered every 2 weeks in adult and paediatric Japanese patients with PIDs.

Real-world treatment patterns and patient-reported outcomes in episodic and chronic migraine in Japan: analysis of data from the Adelphi migraine disease specific programme

Background

In Japan, detailed information on the characteristics, disease burden, and treatment patterns of people living with migraine is limited. The aim of this study was to compare clinical characteristics, disease burden, and treatment patterns in people with episodic migraine (EM) or chronic migraine (CM) using real-world data from clinical practice in Japan.

Methods

This was an analysis of data collected in 2014 by the Adelphi Migraine Disease Specific Programme, a cross-sectional survey of physicians and their consulting adult patients in Japan, using physician and patient questionnaires. We report patient demographics, prescribed treatment, work productivity, and quality-of-life data for people with CM (≥15 headache days/month) or EM (not fulfilling CM criteria). In descriptive analyses, continuous and categorical measures were assessed using t-tests and Chi-squared tests, respectively.

Results

Physicians provided data for 977 patients (mean age 44.5 years; 77.2% female; 94.5% with EM, 5.5% with CM). A total of 634/977 (64.9%) invited patients (600 with EM; 34 with CM) also provided data. Acute therapy was currently being prescribed in 93.7% and 100% of patients with EM and CM, respectively (p = 0.069); corresponding percentages for current preventive therapy prescriptions were 40.5% and 68.5% (p < 0.001). According to physicians who provided data, preventive therapy was used at least once by significantly fewer patients with EM than with CM (42.3% vs. 68.5%, respectively; p < 0.001). Among patients who provided physicians with information on issues with their current therapy (acute therapy: n = 668 with EM, n = 38 with CM; preventive therapy: n = 295 with EM, n = 21 with CM), lack of efficacy was the most frequently identified problem (acute therapy: EM 35.3%, CM 39.5% [p = 0.833]; preventive therapy: EM 35.3%, CM 52.4% [p = 0.131]). Moderate-to-severe headache-related disability (Migraine Disability Assessment total score ≥ 11) was reported by significantly fewer patients with EM than with CM (21.0% vs. 60.0%, respectively; p < 0.001) among patients who provided data.

Conclusions

Preventive treatment patterns in people with EM versus CM differ in Japan, with both types of migraine posing notable disease burdens. Our findings demonstrate that more effective migraine therapies are required to reduce the burden of the disease.

Electronic supplementary material

The online version of this article (10.1186/s10194-019-1012-1) contains supplementary material, which is available to authorized users.

Analysis of HAM-D scores and working ability in an observational study of Japanese patients with major depressive disorder and painful physical symptoms treated with duloxetine or SSRI monotherapy

OBJECTIVE

To investigate the relationship between Hamilton Depression Rating Scale (HAM-D) score and psychiatrists' judgment of working ability in patients with major depressive disorder (MDD) and painful physical symptoms.

METHODS

This was a prospective, observational, 12-week study in patients who received duloxetine or a selective serotonin reuptake inhibitor. Patients were ≥20 years old, resided in Japan, and had at least moderate depression (Quick Inventory of Depressive Symptomatology ≥16) and at least moderate painful physical symptoms (Brief Pain Inventory-Short Form average pain ≥3). The main outcome in this post-hoc analysis was the HAM-D17 cutoff best corresponding with patients' working ability according to the investigator's judgment. Area under the receiver-operator curve was used to determine the time point with the strongest relationship between HAM-D17 and working ability. The optimal HAM-D17 cutoff was determined based on the maximum of sensitivity (true positive rate) minus ([1 minus specificity] [true negative rate]). For the evaluation of binary data, a mixed effects model with repeated measures analysis was used.

RESULTS

For the estimation of the HAM-D17 cutoff, the area under the receiver-operator curve was maximal at 12 weeks, when a HAM-D17 score of 6 resulted in the best correspondence with working ability in the combined study population. At 12 weeks, a HAM-D17 score of 6 also resulted in the maximum predictive ability in each of the two treatment groups separately. For predicted working ability at 12 weeks, 52.7% of duloxetine-treated patients achieved the HAM-D17 cutoff of ≤6, whereas 48.5% of SSRIs-treated patients achieved HAM-D17 ≤6 (P=0.477).

CONCLUSION

In this study of patients with major depressive disorder and painful physical symptoms, a HAM-D17 score ≤6 corresponded best with patients' working ability. This finding is consistent with previous studies showing that a HAM-D17 cutoff of ≤7 may overestimate functional recovery from MDD.

An observational study of duloxetine versus SSRI monotherapy in Japanese patients with major depressive disorder: subgroup analyses of treatment effectiveness for pain, depressive symptoms, and quality of life

OBJECTIVE

To examine how clinical and demographic patient baseline characteristics influence effectiveness of duloxetine versus selective serotonin reuptake inhibitor (SSRI) treatment, in real-world Japanese clinical settings of patients with major depressive disorder (MDD) and associated painful physical symptoms (PPS).

METHODS

This was a multicenter, 12-week, prospective, observational study in patients with MDD (Quick Inventory of Depressive Symptomatology ≥16) and at least moderate PPS (Brief Pain Inventory-Short Form [BPI-SF] average pain ≥3). Patients received duloxetine or SSRIs (escitalopram, sertraline, paroxetine, or fluvoxamine). Assessments were made by using BPI-SF average pain, 17-item Hamilton Rating Scale for Depression (HAM-D17), EuroQol 5-dimension questionnaire, Social Adaptation Self-Evaluation Scale, Global Assessment of Functioning, and ability to work. Predefined subgroups included the number of previous episodes of depression (0 vs ≥1), baseline BPI-SF average pain score (≤6 vs >6), baseline HAM-D17 total score (≤18 vs >18), baseline HAM-D17 retardation (≤7 vs >7) and anxiety somatic subscale scores (≤6 vs >6), and age (<65 vs ≥65 years).

RESULTS

Treatment effectiveness was evaluated in 523 patients (duloxetine N=273, SSRIs N=250). Treatment with duloxetine was superior to SSRIs on most outcome measures in patients experiencing their first depressive episode, those with higher baseline PPS levels, and in patients with more severe baseline depression. This was also the case for older patients. In patients with less severe depression, SSRI treatment tended to show more improvements in depression and quality of life measures versus duloxetine treatment.

CONCLUSION

These preplanned subgroup analyses of data from a prospective observational study suggest that, for Japanese MDD patients with PPS, duloxetine is more effective than SSRIs in patients with a first episode of MDD, with more severe depression, or more severe PPS.

An observational study of duloxetine versus SSRI monotherapy for the treatment of painful physical symptoms in Japanese patients with major depressive disorder: primary analysis

OBJECTIVE

The objective of this study was to assess the effectiveness of duloxetine monotherapy, in comparison with selective serotonin reuptake inhibitor (SSRI) monotherapy, in the treatment of painful physical symptoms (PPS) in Japanese patients with major depressive disorder (MDD) in real-world clinical settings.

METHODS

This was a multicenter, 12-week prospective, observational study. This study enrolled MDD patients with at least moderate PPS, defined as a Brief Pain Inventory-Short Form (BPI-SF) average pain score (item 5) ≥3. Patients were treated with duloxetine or SSRIs (escitalopram, sertraline, paroxetine, or fluvoxamine) for 12 weeks, and PPS were assessed by BPI-SF average pain score. The primary outcome was early improvement in the BPI-SF average pain score at 4 weeks post-baseline.

RESULTS

A total of 523 patients were evaluated for treatment effectiveness (duloxetine N=273, SSRIs N=250). The difference in BPI-SF average pain score between the two groups was not statistically significant at 4 weeks post-baseline, the primary endpoint (least-squares mean change from baseline [95% confidence interval]: duloxetine, -2.8 [-3.1, -2.6]; SSRIs, -2.5 [-2.8, -2.3]; P=0.166). There was a numerical advantage for duloxetine in improvement from 4 to 12 weeks post-baseline, and the difference was statistically significant at 8 weeks post-baseline (least-squares mean change from baseline [95% confidence interval]: duloxetine, -3.6 [-3.9, -3.3]; SSRIs, -3.1 [-3.4, -2.8]; P=0.023). The 30% and 50% responder rates were significantly higher in patients treated with duloxetine at 4 and 8 weeks post-baseline. There were no serious adverse events experienced by duloxetine-treated patients. The rate of discontinuations due to adverse events was similar for duloxetine and the SSRIs (1.0% and 0.8% of patients, respectively).

CONCLUSION

In this observational study, BPI-SF improvement was not significantly different at 4 weeks, the primary endpoint; however, patients treated with duloxetine tended to show better improvement in PPS compared to those treated with SSRIs.

Predicting treatment outcomes of major depressive disorder by early improvement in painful physical symptoms: a pooled analysis of double-blind, placebo-controlled trials of duloxetine

OBJECTIVE

We determined if early improvement in painful physical symptoms (PPS) can be a predictor of remission in the treatment of major depressive disorder (MDD).

METHODS

We included randomized, double-blind, parallel-group clinical trials of duloxetine (40-60 mg/day) versus placebo for the acute treatment of MDD with associated PPS. Only those studies using the Montgomery-Åsberg Depression Rating Scale (MADRS) and the Brief Pain Inventory - Short Form (BPI-SF) were included. Three studies met all criteria and included male or female outpatients aged ≥18 years who met the diagnostic criteria for MDD, had a MADRS total score ≥20, and had at least moderate pain (BPI-SF average pain score ≥3). Positive predictive values (PPVs) and negative predictive values (NPVs) of early improvement in PPS for remission were analyzed. PPVs were the proportion of patients with remission (MADRS total score ≤10) at week 8 out of patients who experienced early improvement in BPI-SF average pain score (≥30% decrease from baseline at week 1, 2, or 4). NPVs were the proportion of patients without remission (MADRS total score >10) at week 8 out of patients who did not experience early improvement in PPS.

RESULTS

Data from 1,320 patients were analyzed (duloxetine N=641 and placebo N=679). The overall remission (MADRS total score ≤10 at week 8) rate for the duloxetine group was significantly higher than the placebo group (38.5% vs 21.8%; P<0.0001). For both treatment groups, PPVs of early improvement in BPI-SF (30% improvement from baseline) were higher than the overall remission rate for all weeks examined (weeks 1, 2, and 4); in general, NPVs of early improvement in BPI-SF for nonremission were higher than the overall nonremission rate.

CONCLUSION

Early improvement in PPS can be a useful clinical indicator of subsequent treatment outcome for MDD patients with associated PPS.

Associations among depression severity, painful physical symptoms, and social and occupational functioning impairment in patients with major depressive disorder: a 3-month, prospective, observational study

PURPOSE

To investigate associations among depression severity, painful physical symptoms (PPS), and social and occupational functioning impairment in patients with major depressive disorder (MDD) who had achieved complete remission (CR) or partial remission (PR) after acute treatment.

PATIENTS AND METHODS

This was a 12-week, multicenter, prospective, observational study. Patients with MDD treated with an antidepressant medication for the previous 12 weeks (±3 weeks) who had achieved CR (defined as a 17-item Hamilton Rating Scale for Depression [HAM-D17] score ≤7) or PR (HAM-D17 score ≥8 and ≤18) were enrolled. Depression severity, PPS, and impairment in social and occupational functioning were assessed using the HAM-D17, the Brief Pain Inventory (Short Form) (BPI-SF), and the Social and Occupational Functioning Assessment Scale (SOFAS), respectively, at enrollment (Week 12) and after 12 weeks (Week 24).

RESULTS

Overall, 323 Japanese patients with MDD were enrolled (CR n=158, PR n=165) and 288 patients completed the study (CR n=139, PR n=149). HAM-D17 and SOFAS scores were strongly and negatively correlated at enrollment (Week 12; P<0.0001) and Week 24 (P<0.0001). A weak negative correlation between the BPI-SF and SOFAS was observed at Week 24 (P=0.0011), but not at enrollment (P=0.164). Remission status at enrollment (CR or PR) was associated with achieving normal social and occupational functioning (SOFAS score ≥80) at Week 24 in patients who had not achieved normal social and occupational functioning (SOFAS score <80) at enrollment (CR vs PR, OR=0.05 [95% CIs 0.01-0.18], P<0.0001). A greater proportion of patients with CR and no PPS at enrollment achieved SOFAS scores ≥80 at Week 24 than those with CR and PPS.

CONCLUSION

Our results suggest that treating both depressive symptoms and PPS is important for achieving a normal level of functioning on a long-term basis in patients with MDD.

Trajectories of depression symptom improvement and associated predictor analysis: An analysis of duloxetine in double-blind placebo-controlled trials

BACKGROUND

In the treatment of major depressive disorder (MDD), it is not fully understood how individual symptoms improve over time (trajectory) in remitters. This study compared symptom improvement trajectories, as measured with the 17-item Hamilton Depression Rating Scale (HAM-D17), in remitters and nonremitters.

METHODS

This analysis is based on 10 placebo-controlled, randomized, double-blind trials of duloxetine (40-60mg/day) for treatment of MDD from baseline up to week 8. Remission was defined as a HAM-D17 total score ≤7 at week 8 (last observation carried forward). Trajectories of HAM-D17 items were assessed by mixed model repeated measures analysis for treatment and remitter-nonremitter comparisons. Grouping of the trajectories was performed by factor analysis. Predictor analysis using HAM-D17 items was conducted by logistic regression.

RESULTS

There were 1555 patients in the duloxetine group (489 [31.4%] remitters) and 1206 patients in the placebo group (290 [24.0%] remitters; P<.0001). For most items, the difference in trajectories between remitters and nonremitters appeared at early time points and increased over time. Treatment response trajectories were very similar for duloxetine and placebo remitters, while duloxetine nonremitters improved more than placebo nonremitters. For duloxetine remitters, we found 3 trajectory groups of HAM-D17 items. The predictor analysis showed that improvement in 6 individual items at week 1 or 2 was significantly associated with remission at week 8.

LIMITATIONS

Generalizability of these results may be limited by the relatively short observation period used to define remission.

CONCLUSIONS

Early monitoring of some symptoms of depression may prove useful in guiding treatment decisions.

Impaired viability of muscle precursor cells in muscular dystrophy with glycosylation defects and amelioration of its severe phenotype by limited gene expression

A group of muscular dystrophies, dystroglycanopathy is caused by abnormalities in post-translational modifications of dystroglycan (DG). To understand better the pathophysiological roles of DG modification and to establish effective clinical treatment for dystroglycanopathy, we here generated two distinct conditional knock-out (cKO) mice for fukutin, the first dystroglycanopathy gene identified for Fukuyama congenital muscular dystrophy. The first dystroglycanopathy model-myofiber-selective fukutin-cKO [muscle creatine kinase (MCK)-fukutin-cKO] mice-showed mild muscular dystrophy. Forced exercise experiments in presymptomatic MCK-fukutin-cKO mice revealed that myofiber membrane fragility triggered disease manifestation. The second dystroglycanopathy model-muscle precursor cell (MPC)-selective cKO (Myf5-fukutin-cKO) mice-exhibited more severe phenotypes of muscular dystrophy. Using an isolated MPC culture system, we demonstrated, for the first time, that defects in the fukutin-dependent modification of DG lead to impairment of MPC proliferation, differentiation and muscle regeneration. These results suggest that impaired MPC viability contributes to the pathology of dystroglycanopathy. Since our data suggested that frequent cycles of myofiber degeneration/regeneration accelerate substantial and/or functional loss of MPC, we expected that protection from disease-triggering myofiber degeneration provides therapeutic effects even in mouse models with MPC defects; therefore, we restored fukutin expression in myofibers. Adeno-associated virus (AAV)-mediated rescue of fukutin expression that was limited in myofibers successfully ameliorated the severe pathology even after disease progression. In addition, compared with other gene therapy studies, considerably low AAV titers were associated with therapeutic effects. Together, our findings indicated that fukutin-deficient dystroglycanopathy is a regeneration-defective disorder, and gene therapy is a feasible treatment for the wide range of dystroglycanopathy even after disease progression.

Absence of post-phosphoryl modification in dystroglycanopathy mouse models and wild-type tissues expressing non-laminin binding form of α-dystroglycan

α-Dystroglycan (α-DG) is a membrane-associated glycoprotein that interacts with several extracellular matrix proteins, including laminin and agrin. Aberrant glycosylation of α-DG disrupts its interaction with ligands and causes a certain type of muscular dystrophy commonly referred to as dystroglycanopathy. It has been reported that a unique O-mannosyl tetrasaccharide (Neu5Ac-α2,3-Gal-β1,4-GlcNAc-β1,2-Man) and a phosphodiester-linked modification on O-mannose play important roles in the laminin binding activity of α-DG. In this study, we use several dystroglycanopathy mouse models to demonstrate that, in addition to fukutin and LARGE, FKRP (fukutin-related protein) is also involved in the post-phosphoryl modification of O-mannose on α-DG. Furthermore, we have found that the glycosylation status of α-DG in lung and testis is minimally affected by defects in fukutin, LARGE, or FKRP. α-DG prepared from wild-type lung- or testis-derived cells lacks the post-phosphoryl moiety and shows little laminin-binding activity. These results show that FKRP is involved in post-phosphoryl modification rather than in O-mannosyl tetrasaccharide synthesis. Our data also demonstrate that post-phosphoryl modification not only plays critical roles in the pathogenesis of dystroglycanopathy but also is a key determinant of α-DG functional expression as a laminin receptor in normal tissues and cells.

[Recent Advances in α-dystroglycanopathy]

Fukuyama-type congenital muscular dystrophy (FCMD), muscle-eye-brain disease (MEB), and Walker-Warburg syndrome (WWS) are autosomal recessive disorders characterized by congenital muscular dystrophy with structural brain and eye abnormalities. Aberrant glycosylation of α-dystroglycan (α-DG) is a common pathomechanism of these disorders. In addition, genetic and glycobiological evidence has shown that abnormal glycosylation of α-DG is also seen in several forms of congenital and limb-girdle-type muscular dystrophies. These disorders are collectively called "α-dystroglycanopathy" and nowadays, this term is widely accepted because it is useful for illustrating a complicated genotype-phenotype correlation of these disorders. α-DG is a membrane-associated protein that interacts with extracellular matrix proteins such as laminin, and abnormal glycosylation of α-DG results in loss of its laminin-binding activity. A number of serine/threonine residues are present in the mucin-like domain of α-DG and are majorly composed of sugar chains. Among these glycans, an O-mannosyl tetrasaccharide (Neu5Ac-α2,3-Gal-β1,4-GlcNAc-β1,2-Man) is important for laminin-binding activity of α-DG. POMT1/2 and POMGnT1, protein products of causative genes of WWS and MEB, respectively, are enzymes that directly catalyze the biosynthesis of this glycan. Recent studies have suggested that a phosphodiester-linked structure on O-mannose is also important for the laminin-binding activity and that mutations in other causative genes of α-dystroglycanopathy, such as fukutin (originally identified as the gene responsible for FCMD) and LARGE, disrupt the post-phosphoryl structure. Here, we review the history of basic and clinical research on α-dystroglycanopathy and refine its clinical spectrum, which should be broadly extended. In addition, we reveal some progress in research on α-dystroglycanopathy including a novel disease mechanism and anti-sense oligonucleotide therapy for FCMD.

Caveolin-3 regulates myostatin signaling. Mini-review

Caveolins, components of the uncoated invaginations of plasma membrane, regulate signal transduction and vesicular trafflicking. Loss of caveolin-3, resulting from dominant negative mutations of caveolin-3 causes autosomal dominant limb-girdle muscular dystrophy (LGMD) 1C and autosomal dominant rippling muscle disease (AD-RMD). Myostatin, a member of the muscle-specific transforming growth factor (TGF)-beta superfamily, negatively regulates skeletal muscle volume. Herein we review caveolin-3 suppressing of activation of type I myostatin receptor, thereby inhibiting subsequent intracellular signaling. In addition, a mouse model of LGMD1C has shown atrophic myopathy with enhanced myostatin signaling. Myostatin inhibition ameliorates muscular phenotype in the model mouse, accompanied by normalized myostatin signaling. Enhanced myostatin signaling by caveolin-3 mutation in human may contribute to the pathogenesis of LGMD1C. Therefore, myostatin inhibition therapy may be a promising treatment for patients with LGMD1C. More recent studies concerning regulation of TGF-beta superfamily signaling by caveolins have provided new insights into the pathogenesis of several human diseases.

Characteristics of depression in Parkinson's disease: Evaluating with Zung's Self-Rating Depression Scale

The purpose of the study was to elucidate characteristics of depression in Parkinson's disease (PD). Fifty-eight PD patients were evaluated with Zung's Self-Rating Depression Scale (SDS) and the Unified Parkinson's Disease Rating Scale (UPDRS). Scores for "suicidal ideation" on the SDS correlated with posture and gait disturbances on the UPDRS. Twenty-six patients with spinocerebellar degeneration (SCD) were also evaluated with the SDS. SDS scores for "indecisiveness" and "constipation" were significantly higher in PD patients than SCD patients. Our results suggest that depression is common in disabled persons but PD patients might have a characteristic clinical presentation.

[A case of orbital apex syndrome caused by localized invasive aspergillosis successfully treated with voriconazole]

A 71-year-old man with left periorbital pain and diplopia was hospitalized for evaluation and treatment. He had a past history of untreated diabetes mellitus. Shortly after admission, the patient experienced rapid onset of visual loss in the left eye. MRI and CT showed a lesion expanding from the left orbital apex to the left pterygopalatine fossa. Invasive aspergillosis was diagnosed by open biopsy of intrasinus mucosa via the left maxillary sinus. The patient was treated with voriconazole, an antifungal agent, and marked improvements in left periorbital pain and eye movement were subsequently obtained, although visual acuity was not recovered. This is the first report documenting the clinical utility of voriconazole for sino-orbital invasive aspergillosis.

[Posterior spinal cord infarction presenting Brown-Séquard syndrome]

We report a 56 year-old-woman with spinal cord infarction. She experienced left-sided girdle pain without precipitating symptoms and she developed monoparesis of her left leg and urinary retention. She also presented the segmental loss of total sensations in the Th10-11 area of the left trunk, the disturbance of position and vibration senses in the left leg and the disturbance of pain and temperature senses in the right leg. T2-weighted MR imagings showed high signal intensity lesion in the left half of the spinal posterior column at Th9-10 vertebral levels. Somatosensory evoked potentials confirmed that the loss of position and vibration senses was unilateral. Though she became able to walk with canes two months later, her sensory disturbance showed no improvement. This is a rare case of unilateral posterior spinal cord infarction presenting Brown-Séquard syndrome.

[Allergic skin rashes by methylprednisolone in a case with multiple sclerosis]

We reported a 34-year-old woman with multiple sclerosis showing an allergic reaction to methylprednisolone sodium succinate. She was admitted to our hospital with a complaint of hypesthesia in the right side of the face and body. MRI showed several high signal intensity lesions in her brain with Gd-DTPA enhancement effect. She was diagnosed as having an acute relapse of MS from previous episodes and clinical findings. We started a methylprednisolone pulse therapy. After the injection on the first day, skin rashes appeared on her trunk and thigh. On the second day, the skin rashes spread over her whole body. Patch test for methylprednisolone sodium succinate (MP) was positive. The steroid administration was substituted by intravenous injections of betamethasone 100mg/day for three days. Her neurological and radiological findings were successfully disappeared without any side effects. This case indicates the efficacy of substitution therapy of betamethasone for MP.

Identification of aminoglycoside-modifying enzymes by susceptibility testing: epidemiology of methicillin-resistant Staphylococcus aureus in Japan

A multiple-primer PCR was used to identify genes encoding aminoglycoside-modifying enzymes in 381 clinical isolates of methicillin-resistant Staphylococcus aureus (MRSA). The technique used three sets of primers delineating specific DNA fragments of the aph(3')-III, ant(4')-I, and aac(6')-aph(2") genes, which influence the MICs of gentamicin, tobramycin, and lividomycin. Isolates with none of the three genes detected were susceptible to all three agents. Isolates with the aph(3')-III gene showed resistance to lividomycin (MIC > 1,024 microg/ml), and those with the ant(4')-I gene were resistant to tobramycin (MIC > or = 8 microg/ml). Isolates with only the aac(6')-aph(2") gene were resistant to gentamicin (MIC > or = 8 microg/ml) and tobramycin in decreasing order; those with both the ant(4')-I and aac(6')-aph(2") genes also were resistant to gentamicin and tobramycin, but in increasing order. Susceptibility testing, then, could detect specific genes. In 381 Japanese MRSA isolates, the ant(4')-I, aac(6')-aph(2"), and aph(3')-III genes were prevalent in 84.5, 61.7, and 8.9%, respectively. Isolates with only the ant(4')-I gene had coagulase type II or III, but isolates with both the ant(4')-I and aac(6')-aph(2") genes included all coagulase types. Most isolates with coagulase type IV or VII carried the aac(6')-aph(2") gene. Of the MRSA isolates with ant(4')-I and/or aac(6')-aph(2") genes, 97% were resistant to aminoglycosides in clinical use, but a new aminoglycoside, arbekacin, had excellent activity against these isolates.

Plasmid-encoded metallo-beta-lactamase (IMP-6) conferring resistance to carbapenems, especially meropenem

In 1996, Serratia marcescens KU3838 was isolated from the urine of a patient with a urinary tract infection at a hospital in northern Japan and was found to contain the plasmid pKU501. Previously, we determined that pKU501 carries bla(IMP) and the genes for TEM-1-type beta-lactamases as well as producing both types of beta-lactamases (H. Yano, A. Kuga, K. Irinoda, R. Okamoto, T. Kobayashi, and M. Inoue, J. Antibiot. 52:1135-1139, 1999). pKU502 is a recombinant plasmid that contains a 1.5-kb DNA fragment, including the metallo-beta-lactamase gene, and is obtained by PCR amplification of pKU501. The sequence of the metallo-beta-lactamase gene in pKU502 was determined and revealed that this metallo-beta-lactamase gene differed from the gene encoding IMP-1 by one point mutation, leading to one amino acid substitution: 640-A in the base sequence of the IMP-1 gene was replaced by G, and Ser-196 was replaced by Gly in the mature enzyme. This enzyme was designated IMP-6. The strains that produced IMP-6 were resistant to carbapenems. The MICs of panipenem and especially meropenem were higher than the MIC of imipenem for these strains. The k(cat)/K(m) value of IMP-6 was about sevenfold higher against meropenem than against imipenem, although the MIC of meropenem for KU1917, which produced IMP-1, was lower than that of imipenem, and the MIC of panipenem was equal to that of imipenem. These results support the hypothesis that IMP-6 has extended substrate profiles against carbapenems. However, the activity of IMP-6 was very low against penicillin G and piperacillin. These results suggest that IMP-6 acquired high activity against carbapenems, especially meropenem, via the point mutation but in the process lost activity against penicillins. Although IMP-6 has reduced activity against penicillins due to this point mutation, pKU501 confers resistance to a variety of antimicrobial agents because it also produces TEM-1-type enzyme.

[Present situation of drug resistance and future prospects]

Antibiotic resistance has evolved over 60 years from a merely microbiological curiosity to a serious medical problem in hospitals. Resistance has been reported in almost all species of bacteria to various classes of antimicrobial agents including recently evaluated ones. Bacteria regulated resistance by different mechanisms. Inappropriate use of an antimicrobial agent selects resistant strains much more frequently. Since it is not expected that some epoch-making new antimicrobial agents will be developed in the near future, proper use of existing antimicrobial agents which is based on the mechanisms of action of antimicrobial agents and of resistance of bacteria, and of control of nosocomial infection are very important to reduce the further spread of resistant bacteria. With the search for natural sources of new antimicrobial substances now appearing frustrated, the genomic approach in the 21st century may be the only fruitful way to develop truly novel chemotherapeutic agents against bacterial diseases.

[In vitro antibacterial activity of prulifloxacin, a new oral quinolone, and comparative susceptibility rate at clinical breakpoint MIC]

In vitro drug sensitivity of clinically isolated bacteria against prulifloxacin (PUFX), which is a new quinolone, was investigated, and the antibacterial activity and susceptibility rate at clinical breakpoint were compared with those of norfloxacin, ofloxacin (OFLX), ciprofloxacin, tosufloxacin, fleroxacin, sparfloxacin and levofloxacin (LVFX). The following results were obtained. 1) PUFX showed a broad-spectrum antibacterial activity against both Gram-positive and Gram-negative bacteria. 2) MIC80 of PUFX was 0.25 and 1 microgram/ml, against methicillin susceptible Staphylococcus aureus and Streptococcus pneumoniae, respectively and below 0.125 microgram/ml against Gram-negative Enterobacteriaceae. MIC90 of PUFX against Pseudomonas aeruginosa, which has MIC not exceeding 4 micrograms/ml to OFLX, was 0.5 microgram/ml. 3) PUFX was judged as active against the bacteria under the criteria proposed presented by "the Sensitivity Determination Committee for Antibiotics, Japan Society of Chemotherapy: Break Point for Respiratory Infectious Diseases and Sepsis". It is suggested that the sensitivity of each bacterial species to PUFX was high. 4) From the correlation analysis of MIC, PUFX was shown to have two to eight times higher antibacterial acitivity than LVFX for Citrobacter freundii, Serratia marcescens and Pseudomonas aeruginosa. 5) PUFX showed potent short-time bactericidal activity against S. aureus and P. aeruginosa.

ampR gene mutations that greatly increase class C beta-lactamase activity in Enterobacter cloacae

The ampC and ampR genes of Enterobacter cloacae GN7471 were cloned into pMW218 to yield pKU403. Four mutant plasmids derived from pKU403 (pKU404, pKU405, pKU406, and pKU407) were isolated in an AmpD mutant of Escherichia coli ML4953 by selection with ceftazidime or aztreonam. The beta-lactamase activities expressed by pKU404, pKU405, pKU406, and pKU407 were about 450, 75, 160, and 160 times higher, respectively, than that expressed by the original plasmid, pKU403. These mutant plasmids all carried point mutations in the ampR gene. In pKU404 and pKU405, Asp-135 was changed to Asn and Val, respectively. In both pKU406 and pKU407, Arg-86 was changed to Cys. The ease of selection of AmpR mutations at a frequency of about 10(-6) in this study strongly suggests that derepressed strains, such as AmpD or AmpR mutants, could frequently emerge in the clinical setting.

Pulsed-field gel electrophoresis analysis of nasopharyngeal flora in children attending a day care center

To investigate how bacterial pathogens spread from child to child in a day care center, we monitored six children, two boys and four girls, born between August 1995 and November 1997, attending a day care center and analyzed nasopharyngeal samples from them using pulsed-field gel electrophoresis (PFGE). We obtained nasopharyngeal cultures from all of the affected children and almost all of the unaffected children between September 1998 and March 1999 after some children presented simultaneously with purulent rhinorrhea. Moreover, when a child was found to have acute otitis media, nasopharyngeal secretions from the child were independently cultured during treatment. During this period, 28 isolates of Moraxella catarrhalis, 13 of Streptococcus pneumoniae, and 4 of Haemophilus influenzae were recovered. PFGE gave 8 patterns for M. catarrhalis, 10 for S. pneumoniae, and 1 for H. influenzae. PFGE patterns demonstrated spread of M. catarrhalis between children. However, each occurrence of clusters of infection with M. catarrhalis lasted 2 to 6 weeks, with a change in PFGE pattern between occurrences of clusters. The M. catarrhalis strain infecting each child also changed. Similarly, the S. pneumoniae strain in each child also changed. In contrast, infection with H. influenzae persisted for about 3 months in an affected child.

[Antibacterial activity of beta-lactam antibiotics against extended-spectrum beta-lactamase producing bacteria]

MICs of various beta-lactam antibiotics by themselves and in combination with beta-lactamase inhibitor (clavulanic acid) against extended spectrum beta-lactamase (ESBL) producing strains of Escherichia coli and Klebsiella pneumoniae which were isolated from clinical materials were investigated. Furthermore, based on the results obtained, a procedure to detect ESBL producing strains was proposed. The MICs of beta-lactam antibiotics against beta-lactamase producing strains were investigated. At first, beta-lactamase was investigated by the drug sensitivity pattern (MIC) to beta-lactam antibiotics and by the substrate profiles of beta-lactamase extracted from the transconjugant of E. coli K-12 strains. After that, we classified the beta-lactamase producing gene by PCR method. Furthermore, a proposal was made for an antibiotic to be used in the confirmation of mixed type beta-lactamase. The data obtained by the above investigations were compiled and used to determine the limit concentration of each beta-lactam against beta-lactamase producing strains including ESBL. By using beta-lactam antibiotics at the following concentrations, it is considered possible to classify beta-lactamase; ampicillin (64 micrograms/ml), ampicillin/clavulanic acid (32/5 micrograms/ml), piperacillin (64 micrograms/ml), cefotaxime (1 microgram/ml), cefpodoxime (2 micrograms/ml), ceftazidime (1 microgram/ml), cefmetazole (4 micrograms/ml), cefminox (2 micrograms/ml), cefepime (0.5 microgram/ml), aztreonam (1 microgram/ml) and imipeneme (1 microgram/ml). This method may be used as a reference in investigating the prevalence of beta-lactam resistant isolates by ESBL producing E. coli and K. pneumoniae.

Why do antimicrobial agents become ineffectual?

Antibiotic resistance has evolved over the past 50 years from a merely microbiological curiosity to a serious medical problem in hospitals all over the world. Resistance has been reported in almost all species of gram-positive and -negative bacteria to various classes of antibiotics including recently developed ones. Bacteria acquire resistance by reducing permeability and intracellular accumulation, by alteration of targets of antibiotic action, and by enzymatic modification of antibiotics. Inappropriate use of an antibiotic selects resistant strains much more frequently. Once resistant bacteria has emerged, the resistance can be transferred to other bacteria by various mechanisms, resulting in multiresistant strains. MRSA is one of the typical multiresistant nosocomial pathogens. A study of the PFGE pattern of endonuclease-digested chromosomal DNA showed that MRSA of a few clones were disseminated among newborns in the NICU of a Japanese hospital. In this regard, it is important to choose appropriate antibiotics and then after some time, to change to other classes to reduce the selection of resistant strains. Since the development of epoch-making new antibiotics is not expected in the near future, it has become very important to use existing antibiotics prudently based on mechanisms of antibiotic action and bacterial resistance. Control of nosocomial infection is also very important to reduce further spread of resistant bacteria.

Detection of tet(K) and tet(M) in Staphylococcus aureus of Asian countries by the polymerase chain reaction

This study describes the use of the polymerase chain reaction (PCR) to detect the tet(K) and tet(M) tetracycline resistance genes in Staphylococcus aureus. Primers based on the DNA sequence of the tet(K) and tet(M) genes from S. aureus were used as primers in the PCR assay to detect the presence of genes for resistance to tetracycline and minocycline. Two-hundred and fifteen isolates of S. aureus from Asian countries as Japan, Indonesia, China, Korea and Thailand were examined, and the results confirm that tet(K) specifies resistance to tetracycline but not to minocycline and tet(M) specifies resistance to both tetracycline and minocycline. We observed two different types of clinical isolates of S. aureus strains resistant to minocycline and tetracycline: the first carried only the tet(M) gene, while the second carried both the tet(M) and the tet(K) genes. Almost all of the clinical isolates of S. aureus resistant to minocycline and tetracycline from Indonesia, China and Thailand carried both tet(M) and tet(K) genes, while most of clinical isolates of S. aureuss from Japan and Korea carried only tet(M) gene.