[Evaluation of Accuracy and Availability of the Antimicrobial Resistance Testing by the Direct Disc Methods Using AmpC/ESBL Differential Discs in the Samples in Which Enterobacterales are Detected in Blood Culture].

The emergence and dissemination of drug-resistant Gram-negative bacilli have been recognized as a serious health concern in worldwide. The isolation rates of Extended-Spectrum ß-lactamases (ESBL) and AmpC ß-lactamases (AmpC) producing gram negative rods are increasing in our hospital. In the present study, we evaluate the availability of the antimicrobial resistance testing by the direct disc methods using AmpC/ESBL differential discs. One hundred and ten strains of Enterobacterales were isolated during the observation period, of which 19 strains (17%) were ESBL-positive and 6 strains (5%) were AmpC-positive. The positive and negative coincidence rate between direct disc methods and standard disc methods were 100%. We conclude that the direct disc method is a useful and rapid detection method for ESBL and AmpC from blood culture samples.

[On the performance evaluation of VersaTREK introduced in blood culture].

We evaluated performance of Versa TREK, blood culture system used in our hospital. Compared with BacT/ALERT 3D, the detection time of bacteria in the VersaTREK was shorter in most of strains. Compared with BacT/ALERT Virtuo, there was little difference in the detection time of bacteria. In addition, VersaTREK was able to detect Helicobacter cinaedi which could not be detected by other equipment, and H. cinaedi was detected in clinical specimens within 2 days. There were 147 bottles judged to be false positives at our facility, of which 7,290 were 2,0% of the total. Ninety one points eight percentage of the cause was due to the change in the temperature inside the device, 3.4% was due to incorrect procedure. So, it is considered that false positives are further decreased by appropriate management of the installation and sample collection.

Enzymatic and genetic characterization of the DasD protein possessing N-acetyl-ß-d-glucosaminidase activity in Streptomyces coelicolor A3(2).

The dasD gene is located just downstream of the dasABC gene cluster, encoding components of an ABC transporter for uptake of a chitin-degradation product N,N'-diacetylchitobiose [(GlcNAc)(2) ] in Streptomyces coelicolor A3(2). To clarify the roles of the DasD protein in the degradation and assimilation of chitin, we obtained and characterized a recombinant DasD protein and a dasD-null mutant of S. coelicolor A3(2). The recombinant DasD protein produced in Escherichia coli showed N-acetyl-ß-d-glucosaminidase (GlcNAcase) activity and its optimum temperature and pH were 40 °C and 7, respectively. dasD transcription was strongly induced in the presence of chitin, weakly by chitosan, but not by cellulose or xylan in S. coelicolor A3(2). Immuno-blot analysis demonstrated that DasD is a cytoplasmic protein. The dasD-null mutant exhibited cellular GlcNAcase activity which was comparable with that of the parent strain M145. DasD, thus, did not seem to be a major GlcNAcase. Induced extracellular chitinase activity in the dasD-null mutant was, interestingly, higher than M145, in the presence of colloidal chitin or (GlcNAc)(2) . In contrast to M145, (GlcNAc)(2) temporally accumulated in the culture supernatant of the dasD-null mutant in the presence of colloidal chitin.

Characterization and usefulness of stool antigen tests using a monoclonal antibody to Helicobacter pylori catalase.

BACKGROUND AND AIM: Two types of stool antigen tests have been used in the management of Helicobacter pylori infection. Testmate Pylori Antigen enzyme immunoassay (TPAg EIA) is a direct sandwich enzyme immunoassay (EIA) while Testmate Rapid Pylori Antigen (Rapid TPAg) is performed using immunochromatography. The aim of this study was to study the characterization and usefulness of these tests. METHODS: Accuracy of both tests was studied using 111 fecal samples obtained from H. pylori-positive or -negative patients. Cross-reactivity was examined with four other Helicobacter spp. and five fecal bacteria in humans. To estimate the sensitivity of both kits, we tested H. pylori clinical strains. We also examined the diagnostic performances of both tests after the storage for 12 months. RESULTS: The accuracy of both Testmate kits was 100% in fecal samples from 111 patients. No cross-reactivity was observed in both Testmate kits in five fecal bacteria and four other Helicobacter spp. TPAg EIA and Rapid TPAg showed positive results in 1342 of 1344, and 483 of 485 clinical strains, respectively. Diagnostic performances was maintained for 12 months when TPAg EIA was stored at 4°C and Rapid TPAg at 30°C. CONCLUSIONS: We examined the details of high accuracy of TPAg EIA and Rapid TPAg. The diagnostic performance of both kits was maintained after storage for up to 1 year. The two types of tests would be useful in the management of H. pylori infection.

Hoffmann reflex in a rat bipedal walking model.

The rat bipedal walking model (RBWM) refers to rats that acquired anatomical and functional characteristics for bipedal walking after the completion of a long-term motor training program. We recorded the Hoffmann reflex (H-reflex) of the forelimb and hindlimb in RBWM and control (not trained, normal) rats to evaluate the effects of bipedal walking on central nervous system (CNS) activity. The H-reflex recorded from the hindlimbs of the RBWM was significantly inhibited compared with that in the control. Furthermore, the inhibition of the H-reflex recorded from both forelimbs and hindlimbs by paired pulse stimulation tended to be enhanced in RBWM. These results indicate that bipedal walking or bipedal walking training cause functional changes in spinal reflex pathways in the CNS.

The polysynaptic pathways from the low threshold cutaneous afferents of the trunk to motoneurons innervating hindlimb muscles in the spinal cat.

We studied the reflex actions of the cutaneous afferents innervating the trunk to hindlimb motoneurons in the spinal cat using an intracellular recording technique. Stimulation of the trunk cutaneous afferents entering into the L2-L5 spinal segment produced different types of polysynaptic potentials in hindlimb motoneurons via polysynaptic neuronal pathways. The trunk cutaneous afferents predominantly caused excitatory PSPs in the flexor motoneurons and inhibitory PSPs in the extensor motoneurons. The size and latency of polysynaptic potentials were related to the proximity of the spinal segments of the nerves stimulated to the spinal segments of motoneurons. These findings suggest that the neuronal pathways from trunk cutaneous afferents to hindlimb motoneurons play an important role in coordinating between the trunk and hindlimbs.

Characterization and application of a new monoclonal antibody with high specificity for Helicobacter hepaticus.

BACKGROUND AND AIMS: Infection with Helicobacter hepaticus is suggested to play a role in the pathogenesis of chronic liver disease in humans. However, reactive antigens among Helicobacter species make the development of an H. hepaticus ELISA test with high specificity difficult. A new monoclonal antibody from a hybridoma clone (HRII-51) showed high specificity to H. hepaticus without cross-reaction to other gastrointestinal bacteria. METHODS: The molecular weight of HRII-51 immunoreactive antigen was examined by Western blot of H. hepaticus probed with the monoclonal antibody HRII-51. A HRII-51-immunoreactive antigen capture ELISA was prepared in which the specific antigen was anchored by HRII-51-immobilized ELISA plate. Accuracy of HRII-51 antigen capture ELISA was examined using sera obtained from mice inoculated with Helicobacter species. Specificity of HRII-51 antigen capture ELISA was compared to that of H. hepaticus antigen-based ELISA using human sera with absorption by H. pylori cell lysate. RESULTS: HRII-51 immunoreactive antigen had a molecular weight of 15 kDa. Sensitivity and specificity of HRII-51 antigen capture ELISA were 87.0% and 97.6% in mice inoculated with Helicobacter species. In human sera, modification of the results by absorption with H. pylori lysate was smaller in HRII-51 antigen capture ELISA comparing with H. hepaticus-antigen-based ELISA. CONCLUSION: Use of the HRII-51 antigen capture ELISA would be a useful approach for the serodiagnosis of H. hepaticus infection in both experimental animals and humans.