Tatsuya Morooka

Motility as an intestinal colonization factor for Campylobacter jejuni

The colonization of the intestinal tract of suckling mice by Campylobacter jejuni was examined by orally challenging the mice with a wild-type strain and several nonmotile mutant strains which were isolated after treating the wild-type strain with mutagens. The wild-type strain had colonized the lower portion of the small intestine, the caecum and the colon 2 d after inoculation. Two nonmotile strains, one of which (M8) had lost all the flagellar structure including the filament, the hook and the basal structure, and the other (M1) which had lost only the filament region, were both cleared from the intestinal tract 2 d after challenge. Another nonmotile strain (M14), which had a complete flagellar structure like that of the wild-type strain, did not colonize and was cleared from the intestinal tract like the other nonmotile and nonflagellated strains. One atypically motile strain (M5), which had a shorter flagellar filament than that of the wild-type strain, colonized the intestinal tract only when mice were challenged with a large inoculum. None of the mice challenged with either the wild-type or any of the mutant strains showed signs of illness. We concluded that motility is an important factor in the colonization of the intestinal tract of suckling mice by C. jejuni.

Epidemiologic Application of Pulsed-Field Gel Electrophoresis to an Outbreak of Campylobacter fetus Meningitis in a Neonatal Intensive Care Unit

An outbreak of nosocomial Campylobacter fetus meningitis occurred in a neonatal intensive care unit (NICU). Eight C. fetus strains were isolated from 4 infants with meningitis, the mother of the index patient and 2 infants who were asymptomatic intestinal carriers. The pulsed-field gel electrophoresis (PFGE) pattern with the restriction endonucleases Smal and Sall were found to be identical for the nosocomial C. fetus isolates, but the patterns were different from those of sporadic strains. These nosocomial strains were strongly suspected to be a single strain. The finding revealed that the index patient was infected by the mother, and that the outbreak developed from this patient by cross-infection. This is the first confirmed nosocomial C. fetus meningitis outbreak spread by cross-infection in a NICU.

Southern blotting analyses of strains ofCampylobacter fetus using the conserved region ofsapA

Chromosomal DNA of 27 strains ofCampylobacter fetus was analyzed by Southern blotting with a probe of the conserved region ofsapA. The probe hybridized with 23 strains that produced type A lipopolysaccharide. These strains had more than sixsapA homologs. In Southern blots ofSalI-digested chromosomal DNA separated by pulsed-field gel electrophoresis, one fragment from 19 strains and two fragments from 4 strains hybridized. These data indicate that multiplesapA homologs are localized to a limited region on the chromosomal DNA ofC. fetus and thus suggest the possibility of developing a typing system using this method.

Prevention of Exercise-Induced Bronchospasm in Asthmatic Children Effect of Aerosol and Oral Procaterol Hydrochloride

This double-blind crossover study compared the therapeutic value of bronchodilator procaterol hydrochloride at 5 micrograms per puff by aerosol inhalation using a metered-dose inhaler and at 25 micrograms by oral administration using tablets with respective inert placebos in preventing exercise-induced bronchospasm (EIB) in 10 children with bronchial asthma. The two active dosage formulations produced a significant EIB inhibitory effect compared with the placebos. In a comparison of the two active preparations, the aerosol was more efficacious than the tablet in improving all respiratory parameters examined, and statistical significance was obtained in FEV1, MMEF, PEFR, V50, and V25 5 minutes after exercise. Further, the aerosol was beneficial in all subjects, while the tablet was beneficial in seven of 10.

Anti‐verocytotoxin (VT)1, VT2 and VT2c antibodies in commercial intravenous immune globulins in Japan

Verocytotoxin-producing Escherichia coli (VTEC), which is also called enterohemorrhagic E. coli, is the most important cause of hemolytic uremic syndrome (HUS).’ Verocytotoxin (VT) is also referred to as Shiga-like toxin (SLT).* The precise mechanism by which VTEC infection causes HUS has not been fully elucidated but is thought to be related to the secondary effects of systemically absorbed VT. It has been suggested that the first step is injury to endothelial cells of the glomerulocapillaries of the kidney by VT. In order to determine whether commercial intravenous immune globulin (IVIG) available in Japan has a potentially beneficial effect on Japanese HUS patients, we checked the antibodies to three VT types (VT1, VT2 and VT2c) in the WIG.

髄液より特異DNAが検出され, interleukin-6が高値を示したマイコプラズマ脳炎の1小児例

A 9-year-old female was admitted to our hospital due to a generalized seizure and consciousness disturbance. The patient had a fever and rash four days before admission, but she had no respiratory symptoms. The seizure and consciousness disturbance was prolonged and intractable. We diagnosed the patient as having encephalitis because of the increase in the cell count in the cerebrospinal fluid (CSF) and a diffuse slow EEG wave. The computed tomography of the head was normal. The causative agent was identified as Mycoplasma pneumoniae because of the increase of antibodies, and the detection of a specific DNA with a polymerase chain reaction. The interleukin (IL)-6 level of CSF was high (384 pg/ml). In spite of intensive treatment she had severe neurological sequelae. The invasion of Mycoplasma pneumoniae to the central nervous system appeared to have a role in the development of encephalitis in the patient. We speculated that there is a possible relationship between the IL-6 levels of CSF and clinical severity of encephalitis.

Indirect hemagglutination assay for antibodies to Escherichia coli lipopolysaccharides O157, O111 and O26 in patients with hemolytic uremic syndrome

We examined sera from 10 patients with hemolytic uremic syndrome (HUS) and 51 controls, with and without diarrhea, for antibodies to Escherichia coli lipopolysaccharides (LPS) O157, O111 and O26 using the indirect hemagglutination (IHA) assay. A significant rise (to a titer of ≥ 2560) in IHA antibody to O157 LPS was detected in eight of the 10 HUS patients, to O111 in two patients, one of whom showed concomitantly an antibody rise to O157, but to O26 in no patients. The IHA titers fell rapidly after the acute phase of the illness. Of the control sera 15 (29.4%) non‐specifically agglutinated uncoated sheep red blood cells (SRBC) at a titer of ≥80, six (3.9%) at ≥320 and the maximum was 640. In spite of the relatively low level of non‐specific agglutination the IHA appeared to be a useful screening method to identify verotoxin‐producing E. coli infections at the early stage of HUS because the titers were clearly higher than non‐specific agglutination and the assay is easy to perform and gives results quickly. Artificial carriers are being considered for use in place of SRBC to diminish the non‐specific hemagglutination.

Morphological Differences in Flagella in Campylobacter fetus Subsp. intestinalis and C. fetus Subsp. jejuni

Intact flagella were isolated from human pathogenic strains of Campylobacter, C. fetus subsp. intestinalis and C. fetus subsp. jejuni, by the method of DePamphilis and Adler and examined by electron microscopy. The isolated flagella were composed of a filament, a hook, a basal body, and a large disk associated with the end of the hook region covering the basal body. The width of the hook was approximately 28 nm, somewhat greater than that of the filament (20 nm in diameter). The hook region of C. fetus subsp. intestinalis was curved, but it was straight in C. fetus subsp. jejuni. The structure of the basal body of the two subspecies was similar to that reported for other gram‐negative bacteria. The large disk detached from the flagella showed concentrically arranged circular structures. This structure was more clearly observed in the disk of C. fetus subsp. jejuni than in C. fetus subsp. intestinalis. Observations of thin‐sectioned profiles at the attachment site of the flagellum revealed that the large disk is located on the inner side of the outer membrane. The role of the large disk in bacterial movement is not clear, but it is assumed that it acts as an organ to protect the flagellar insertion site from vigorous rotation of the polar end inflicted during bacterial movement.