Masaru Nasu’s research while affiliated with Society of General Internal Medicine and other places

It has been more than 4 years since third-generation cephems were introduced into clinical practice. The range of our drug selection definitely tends to increase, because we today have more antibiotics with wider spectrum, antibiotics with strong activities only against Gram-negative strains, such as monobactams, and those with tremendously high activities such as quinolone carboxylic acid derivatives, in comparison to those we had in the past. Among isolates obtained mainly from sputa of 567 patients with lower respiratory tract infections at 16 institutions throughout Japan between September of 1985 and March of 1986, 741 strains were determined to be causative organisms. MIC's of various antimicrobial agents were determined against 67 strains of Staphylococcus aureus, 100 strains of Streptococcus pneumoniae, 199 strains of Haemophilus influenzae, 92 strains of non-mucoid Pseudomonas aeruginosa, 40 strains of mucoid P. aeruginosa, 29 strains of Klebsiella pneumoniae, 10 strains of Escherichia coli and for 42 strains of Branhamella catarrhalis out of the above 741 strains to determine their drug sensitivities. As for types of lower respiratory tract infections found in 1981-1983, 57.9-64.5% of the infections were chronic respiratory infections; i.e., chronic bronchitis, chronic bronchiolitis and bronchiectasis. These chronic infections, including diffuse panbronchiolitis (DPB), were found in 63.1% of lower respiratory tract infections in 1984. Their incidence dropped to 54.0% in 1985, even through DPB was included; i.e., the incidence of chronic bronchiolitis was 5.5%, that of DPB was 7.1%, and that of bronchial asthma associated with lower respiratory tract infections in 1985 was 8.8% which was twice as much as that found in 1981-1984. Although bacterial pneumonia was found in 24.8% of all the cases in 1981, its incidence was reduced to 11.0% in 1983, 15.1% in 1984, and 17.6% in 1985. This reduction seemed to have resulted from gradual decreases in the occurrence of bacterial pneumonia among the young population. As with usual years, a high incidence rate in a total lower respiratory tract infections in 1985 was found among older patients; namely, 73.5% was at the age of 50 or over (417/567). Next, we determined relationships between clinical isolates and isolates from respiratory infections, including chronic bronchitis, chronic bronchiolitis, bronchiectasis and DPB. H. influenzae was isolated from 50.5% of patients with these infections in 1981; however, the detection rate decreased by about 20% to 29.7% in 1985. P. aeruginosa was consistently isolated, between 24.1% and 30.4% every year. S. aureus and S. pneumoniae were isolated from 15.5% in 1981 and 20.3% in 1985, indicating a tendency toward increases. The detection rate for other Gram-negative bacteia also increased to 14.0% from 0%; Although B. catarrhalis was included in the groups of Gram-negative bacteria in 1981, its single detection was counted to be 5.1% in 1984 and 5.9% in 1985. These results suggested that clinical isolates were more diversified in species year by year. The trend was similar in bacterial pneumonia, the detection rate of Gram-positive cocci, including S. aureus and S. pneumoniae, being 32.4%. The relation of antibiotic treatments to the number of isolates, which were then determined to species was examined. A total of 534 strains, mainly consisting of H. influenzae at 35.4% and S. pneumoniae at 17.4%, were isolated before treatment. The number of isolates decreased to 27 strains within 3 days after the start of treatment due to the presence of strong antibiotic effects, as we expected. However, when the treatment was prolonged to over 15 days, 92 strains were isolated and resistant strains increased in number, because infections might have become chronic. P. aeruginosa was isolated from as high as 51.1% of cases treated for a long period of time, proving the intractable nature of this organism.

A 33-year-old man underwent allogeneic bone marrow transplantation from a non-blood relatives at the age of 31 years for chronic myelogenous leukemia. A sudden rise in transaminases was observed 40 days after transplantation and he was diagnosed as acute GVHD. Elevated hepatobiliary enzymes and pancytopenia continued, and acute GVHD shifted to chronic GVHD. He started taking prednisolone and cyclosporin. Erythema and sclerosis appeared over his entire body 10 months after transplantation. Improvement of the skin lesions was not observed. He was hospitalized in our Department of Dermatology in July, 2003. There were few hairs, thick scales and crusts adhered to the head. Depigmentations and erosions with scales and blood crusts were observed on his face. Pigmentations and depigmentations existed widely on his body and limbs. On all fingers and toes, nail plates disappeared and digital flexions were limited. Several ulcers were observed on both heels and the lateral sides of the soles. The largest one was 5 X 3 cm. A biopsy specimen showed subepidermal blister, exocytosis, vacuolar alteration and necrotic keratinocytes. Lymphocytes infiltrated mildly in the upper dermis and densely around skin appendages in the middle and lower dermis. A direct immunofluorescence test did not show a deposit of either C3 or IgM. Anemia, elevated hepatobiliary enzymes and CRP, and decreased immunoglobulin were observed. Antinuclear antibody was negative. He was treated with oral cyclosporin and prednisolone and an ointment of difluprednate and Azurene. Skin lesions improved by loading with cyclosporin. However cyclosporin was replaced by tacrolimus hydrate because of leucocytopenia and thrombocytopenia. Ulcers and erosions epithelialized except for the one on the right heel, which epithelialized very slowly in spite of restriction of walking and trying various kinds of ointments or dressing agents. The ulcer of the right heel reduced and epithelialized by use of trafermin in combination with tretinointocoferil. He left the hospital in November 2003 and five months after the discharge, the ulcer of the right heel epithelialized.

A 62-year old female was admitted for a detailed study of a pancreatic abnormality detected by abdominal ultrasonography. A CT and MRI revealed a fat deposition in the body and tail of the pancreas. An ERCP demonstrated the distal main pancreatic duct as 2 fine branches in the head, and accessory pancreatic ducts were visualized. An endoscopic ultrasonography revealed a swelling of the body. In the tail, a membrane-like hyperechoic structure was noted, and probably represented the pancreatic capsule. A angiography demonstrated branches of the dorsal and transverse pancreatic artery, and the diagnosis of acquired fatty replacement of the body and tail of the pancreas was confirmed. Endoscopic ultrasonography appears to be a useful method to confirm fatty replacement of the body and tail of the pancreas.

Surveillance of Helicobacter pylori antimicrobial susceptibility reflecting the general population in Japan is limited. The antimicrobial susceptibilities of 3,707 H. pylori strains isolated from gastric mucosa samples of previously untreated patients diagnosed with gastroduodenal diseases at 36 medical facilities located throughout Japan between October 2002 and September 2005 were evaluated. Using an agar dilution method for antimicrobial susceptibility testing of H. pylori, the MIC distributions and trends during the study period for clarithromycin, amoxicillin, and metronidazole were studied. While the MIC50 and MIC90 for clarithromycin did not change during the 3-year period, the MIC80 showed a 128-fold increase. Furthermore, the rate of resistance increased yearly from 18.9% (2002 to 2003) to 21.1% (2003 to 2004) and 27.7% (2004 to 2005). With a resistance rate of 19.2% among males compared to 27.0% among females, a significant gender difference was observed (P < 0.0001). Our study shows that in Japan, there is an evolving trend towards increased resistance to clarithromycin with geographical and gender differences as well as between clinical disease conditions. No significant changes in resistance were observed for amoxicillin and metronidazole during the period. While the benefit of H. pylori antimicrobial susceptibility testing has been debated in Japan, current empirical regimens are not based on susceptibility data representative of the general population. The development of an effective H. pylori eradication regimen in Japan will require continued resistance surveillance as well as a better understanding of the epidemiology of resistance.

Diffuse panbronchiolitis (DPB) is a distinctive form of small airway disease, which is characterized by chronic inflammation with lymphocyte infiltration around bronchioles. The aim of this study was to evaluate the importance of factors related to apoptosis in peribronchiolar lymphocytes of DPB. We employed immunohistochemical methods for the localization of Bax (a promoter of apoptosis), Bcl-2 (an inhibitor of apoptosis), and caspase-3 (a key executioner molecule of apoptosis) in lung tissues of five patients with DPB. In all patients, immunostaining for Bax was almost completely absent in accumulated lymphocytes around the bronchioles and in lymphocytes of the parafollicular area that correspond to a zone populated by T cells. In contrast to the reaction for Bax, Bcl-2 immunoreactivity was uniformly strong in all of the patients. The pattern of staining for caspase-3 was similar to that for Bax in all of the patients. In normal lung tissue, a few lymphocytes showed negative immunostaining for Bcl-2 and a positive reaction for caspase-3. Our results suggest that Bcl-2 protein may provide T-lymphocyte survival and hypercellularity in the bronchioles, thereby contributing to the progression of DPB.

From October 2004 to September 2005, we collected the specimen from 319 patients with lower respiratory tract infections in 12 institutions in Japan, and investigated the susceptibilities of isolated bacteria to various antibacterial agents and patients' characteristics. Of 383 strains that were isolated from specimen (mainly from sputum) and assumed to be bacteria causing in inflammation, 381 strains were examined. The breakdown of the isolated bacteria were: Staphylococcus aureus 87, Streptococcus pneumoniae 80, Haemophilus influenzae 78, Pseudomonas aeruginosa (non-mucoid) 35, P. aeruginosa (mucoid) 9, Klebsiella pneumoniae 15, Moraxella subgenus Branhamella catarrhalis 30, etc. Of 87 S. aureus strains, those with 2μg/mL or less of MIC of oxacillin (methicillin-sensitive S. aureus: MSSA) and those with 4μg/mL or more of MIC of oxacillin (methicillin-resistant S. aureus: MRSA) were 40 (46.0%) and 47 (54.0%) strains, respectively. Against MSSA, imipenem had the most potent antibacterial activity and inhibited the growth of all the strains at 0.063μg/mL. Against MRSA, vancomycin showed the most potent activity and inhibited the growth of all the strains at 1μg/mL. Arbekacin (ABK) also showed the potent activity and its MIC90 was 2μg/mL. Carbapenems showed the most potent activities against S. pneumoniae and inhibited the growth of all the strains at 0.25-0.5μg/mL. Cefozopran (CZOP) also had a preferable activity (MIC90: 1μg/mL) and inhibited the growth of all the strains at 2μg/mL. In contrast, there were high-resistant strains (MIC: 128μg/mL or more) for ABK (2.5%), erythromycin (37.5%), and clindamycin (38.8%). Against H. influenzae, levofloxacin showed the most potent activity and inhibited the growth of all the strains at 0.125μg/mL.Meropenem showed the most potent activity against P. aeruginosa (mucoid) and inhibited the growth of all the strains at 2μg/mL. Against P. aeruginosa (non-mucoid), amikacin (AMK) had the most potent activity and its MIC90 was 4μg/mL. The activity of CZOP against the non-mucoid type also was preferable and its MIC90 was 8μg/mL. Against K. pneumoniae, CZOP, cefmenoxime, cefpirome, flomoxef were the most potent activity and inhibited the growth of all the strains at 0.063μg/mL. Also, all the agents generally showed a potent activity against M.(B.) catarrhalis and the MIC90 of them were 4μg/mL or less. The approximately half the number (57.0%) of the patients with respiratory infection were aged 70 years or older. Bacterial pneumonia and chronic bronchitis accounted for 50.8% and 23.8% of all the respiratory infection, respectively. The bacteria frequently isolated from the patients with bacterial pneumonia were S. aureus (21.6%), S. pneumoniae (24.7%) and H. influenzae (20.1%). S. aureus (20.9%), S. pneumoniae (16.1%), and H. influenzae (16.1%) also were relatively frequently isolated from the patients with chronic bronchitis. Before the drug administration, the bacteria frequently isolated from the patients were S. pneumoniae (22.3%) and H. influenzae (25.1%). The bacteria relatively frequently isolated from the patients treated with macrolides were P. aeruginosa and the isolation frequency was 43.5%.

We examined the protective effect of intratracheal immunization with Pseudomonas aeruginosa pili protein against respiratory infection caused by P. aeruginosa. Mice were immunized intratracheally or subcutaneously with purified pili protein or bovine serum albumin as a control. Intratracheally but not subcutaneously pili protein-immunized mice showed significant improvement of survival after intratracheal challenge with the PAO1 strain. Furthermore, bacterial cell counts in pili protein-immunized murine lungs were significantly decreased compared to controls at 18 h after the challenge. Antipili protein antibody titers in bronchoalveolar lavage fluid of intratracheally pili protein-immunized mice were higher than in bovine serum albumin immunized mice. However, antipili antibody titers were not increased in bronchoalveolar lavage fluid of subcutaneously pili protein-immunized mice, despite the high serum antipili antibody titers. Inoculation of P. aeruginosa induced immediate increases in interleukin-12 and interferon-gamma in bronchoalveolar lavage fluid of pili protein-immunized mice, reflecting an adequate and rapid immune response against P. aeruginosa respiratory tract infection. Our findings suggest that intratracheal pili protein immunization is effective against respiratory tract infection caused by P. aeruginosa in mice.

This study examined the possible relationship between peptic ulcer recurrence and the presence or absence of maintenance therapy with an H(2)-receptor antagonist performed until evaluation of Helicobacter pylori eradication. The subjects were 483 patients with peptic ulcer (281 gastric ulcer and 202 duodenal ulcer) who were diagnosed as H. pylori positive. After receiving eradication therapy for H. pylori, patients were allocated at random to one of three different maintenance therapies: control group (no maintenance therapy), H(2)-receptor antagonist half-dose group, and H(2)-receptor antagonist full-dose group. The maintenance therapy was performed for 4 weeks until evaluation of H. pylori eradication. Among the 25 patients with a recurrent ulcer, 18 patients (72%) had a recurrence at the time of or before evaluation of H. pylori eradication. In the control group, the rate of ulcer recurrence occurring before evaluation of H. pylori eradication was 10.5% (14/133). This rate was significantly higher than those in the H(2)-receptor antagonist half-dose group (2.9%, 4/136) and the full-dose group (0%, 0/135). The results of this study suggest that maintenance therapy with an H(2)-receptor antagonist performed after eradication therapy until evaluation of H. pylori eradication is likely to greatly reduce the ulcer recurrence rate without affecting evaluation of H. pylori eradication.

Widespread use of eradication therapy for Helicobacter pylori has increased the prevalence of clarithromycin-resistant strains. The purpose of the present paper was to measure the in vitro antibacterial activity of minocycline against H. pylori, and study the effectiveness of minocycline-based first- and second-line eradication therapies. For first-line therapy, 79 patients were randomly assigned to the treatment with rabeprazole, amoxicillin, and clarithromycin or with rabeprazole, amoxicillin, and minocycline. For second-line therapy, 88 patients were tested for sensitivity to metronidazole: 67 patients with metronidazole-sensitive strains received a 7-day course of rabeprazole, minocycline, and metronidazole; the remaining 21 patients were given a 7-day course of rabeprazole, minocycline, and faropenem. There was virtually no resistance to minocycline among the strains tested. The eradication rate of H. pylori infection in first-line therapy was significantly lower for minocycline-containing regimen (38.5%, 15/39) than for clarithromycin-containing regimen (82.5%, 33/40; P < 0.01). For second-line therapy, a high eradication rate against metronidazole-sensitive strains was obtained with rabeprazole, minocycline and metronidazole (85%, 57/67). A combination of rabeprazole, minocycline, and metronidazole is safe and effective for second-line therapy of H. pylori infection. Because this regimen can be administered to patients with penicillin allergy and patients who suffer adverse reactions to amoxicillin, such as diarrhea and other digestive symptoms, it should be considered useful for second- and third-line eradication therapy.