Antimicrobial susceptibility surveillance of obligate anaerobic bacteria in the Kinki area

Obligate anaerobes exist as resident flora in various sites in humans, but they are also emphasized as endogenous causative microorganism of infections. We performed surveillance to understand the trend of drug susceptibility in obligate anaerobic bacteria in the Kinki area of Japan. In the experiment, we used 156 obligate anaerobe isolates collected from 13 institutions that participated in the Study of Bacterial Resistance Kinki Region of Japan. MALDI Biotyper was used to identify the collected strains, and among the 156 test strains, those that could be identified with an accuracy of Score Value 2.0 or more included 6 genera, 30 species, and 144 strains (Bacteroides spp. 77 strains, Parabacteroides sp. 2 strains, Prevotella spp. 29 strains, Fusobacterium spp. 14 strains, Porphyromonas spp. 2 strains, and Clostridioides difficile 20 strains), and they were assigned as subject strains for drug susceptibility testing. The drug susceptibility test was carried out by broth microdilution method using Kyokuto Opt Panel MP ANA (Kyokuto Pharmaceutical Industrial Co., Ltd., Tokyo, Japan) and judged according to CLSI criteria. As a result, Bacteroides and Parabacteroides species showed good sensitivities to tazobactam-piperacillin, imipenem, metronidazole and chloramphenicol, and low sensitivities to ampicillin, cefoperazone and vancomycin. Prevotella species showed good sensitivities to sulbactam-ampicillin, tazobactam-piperacillin, cefmetazole, imipenem, doripenem and metronidazole. Susceptibility rates to other drugs were slightly different depending on the bacterial species. Both Fusobacterium spp. and Porphyromonas spp. showed high sensitivities to many drugs. C. difficile was highly sensitive to vancomycin and metronidazole, having MIC₉₀s of 0.5 μg/mL and ≤2 μg/mL, respectively.     

Lung cancer associated with diffuse pulmonary fibrosis: CT-pathologic correlation

The authors reviewed the computed tomographic (CT) scans and pathologic specimens of 57 histologically proved bronchogenic carcinomas (35 squamous cell carcinomas, 12 small cell carcinomas, and 10 adenocarcinomas) in 47 patients with diffuse pulmonary fibrosis. The patients ranged in age from 61 to 87 years (mean age, 72 years; 42 men and 5 women). On radiography and CT, most tumors (82%) were located in peripheral areas of honeycomb lung. In 50 of the 57 lesions, the tumors were round or lobulated with sharp margins. In seven tumors, including six squamous cell carcinomas and one small cell carcinoma, the tumor invaded the adjacent honeycomb lung and lacked distinct margins. Intratumor lucency was seen in 13 tumors (five solitary and eight multiple). The CT findings, including high-resolution CT scans, were compared with the histologic findings in a subgroup of 29 lesions in 25 patients with available surgical or autopsy specimens. Invasive growth of tumors with unclear margins (four lesions), septal thickening of the contiguous/surrounding honeycombed areas (16 lesions), and discrete masses (nine lesions) with solitary (four of nine) or multiple (five of nine) intratumor lucencies. The lucencies in six of nine patients (67%) with intratumor lucencies were found to represent engulfed cystic airspaces histologically. CT revealed that bronchogenic carcinoma associated with diffuse pulmonary fibrosis has distinct morphologic characteristics that correlate histologically with a specific pattern of tumor growth.     

A pediatric case of acute focal bacterial nephritis; comparison with the reports in Japanese child cases]

We report an 8-year-old boy with acute focal bacterial nephritis (AFBN). At the age of 3 months, he had a history of urinary tract infection and vesicoureteral reflux. He was admitted to our hospital because of high fever and costovertebral angle pain. Although acute pyelonephritis was suspected, neither pyuria nor cultures of blood and urine were positive. An initial ultrasonogram (US) of his kidneys was normal except for bilateral hydronephrosis. Two days later, however, a computed tomography (CT) revealed a poorly enhanced mass in the upper pole of the right kidney. Similar findings were also observed by US. Under the diagnosis of AFBN, he received antibiotics for 3 weeks. Voiding cystourethrogram showed both-sided vesicoureteral reflux and he underwent an operation. At present the mass of the kidney still remains, albeit its size tends to decrease. We suggest that an early examination of US or enhanced CT is necessary in cases with fever of unknown origin, considering the possibility of AFBN even if neither pyuria nor cultures of urine are positive.     

Alterations in calcium-handling of erythrocytes in spontaneously hypertensive rats. Calcium-induced changes in the osmotic fragility of erythrocytes in hypertension

To investigate the sensitivity to calcium of erythrocytes in hypertension, changes in the osmotic fragility of erythrocytes following Ca-loading were observed. Washed erythrocytes were obtained from spontaneously hypertensive rats (SHR, Okamoto and Aoki) and age-matched normotensive Wistar Kyoto rats (WKY). Treatment of erythrocytes with Ca-ionophore A23187 and Ca in the medium caused a reduction in the osmotic fragility which correlated with the Ca-concentration. The degree of alteration in the osmotic fragility of erythrocytes was greater in SHR than in WKY. Oral administration of hydralazine to SHR significantly reduced the blood pressure. However, the alterations in the osmotic fragility of erythrocytes secondary to Ca-loading were not different between hydralazine-treated and untreated SHR. In the presence of a Ca-antagonist (verapamil or diltiazem) in the medium, the reduction of the osmotic fragility of erythrocytes caused by Ca-loading was inhibited, and the differences between SHR and WKY were abolished by Ca-antagonists. These results suggest that the greater changes in osmotic fragility of erythrocytes caused by Ca-loading in SHR could be due to a genetic abnormality of Ca-handling by the cell membranes, and that this abnormality might cause an increase in intracellular Ca, which contributes, in part, to the pathogenesis of hypertension.     

A case of Sj?gren's syndrome with valvular diseases

The case of a 61 year old woman with Sj?gren's syndrome with aortic and mitral stenosis is reported. She suffered from rheumatic fever at a young age. Physical and echocardiographic examinations showed findings of mitral and aortic valve stenosis. In addition, she had experienced xerostomia, a gritty sensation in the eyes and Raynaud's phenomenon. Blood examination showed hypergammaglobulinemia, positive rheumatoid factor, antinuclear and anti-Ro (SS-A) antibodies. The diagnosis of Sj?gren's syndrome was confirmed by sialography and biopsy of the labial salivary gland. The combination of valvular disease and Sj?gren's syndrome is rare and the etiological correlation is discussed.     

Measurement of cardiac output by the thermodilution method in conscious spontaneously hypertensive rats

The usefulness of the thermodilution method for measuring cardiac output (CO) was evaluated in awake rats by comparison with electromagnetic flowmetry. CO was measured in 3- and 6-month-old conscious spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto rats (WKY). The correlation co-efficient between CO obtained by the two methods was 0.66 (p less than 0.01). Although CO values obtained by the thermodilution technique tended to be overestimated in comparison with those determined by electromagnetic flowmetry, this method was shown to be useful for measuring CO in unanesthetized rats because of its technical simplicity. Left ventricular mass (LVM) and the ratio of CO to LVM were significantly greater in SHR than in WKY at both ages and CO/LVM increased with increasing age in SHR. The ratio of heart work (HW) to body weight (HW/BW) was increased only in 3-month-old SHR compared with WKY and there was no difference in HW/LVM in 3- and 6-month-old SHR compared with age-matched WKY. The present results suggest that the development of cardiac hypertrophy in SHR is an adaptation to the increased HW due to high afterload.     

Intracellular free calcium concentration, Ca++ channel and calmodulin level in experimental hypertension in rats

Using fluorescent calcium indicator quin2, we studied intracellular free calcium concentration in platelets that have a number of features similar to vascular smooth muscle cells. Intracellular free calcium concentration in platelets of male SHR was significantly higher at 4, 11 and 28 weeks old compared with age-matched male WKY. However, no significant difference was observed in platelets cytosolic free calcium level of DOCA-salt hypertensive and two-kidney, one clip hypertensive rats in the chronic stage. Cardiac Ca++ channels were estimated by means of radioligand binding method with [3H]-nimodipine. No significant changes were observed in the concentration and affinity of cardiac Ca++ channel in SHR, DOCA-salt hypertensive and two-kidney, one clip hypertensive rats. Calmodulin levels in mesenteric arteries of SHR were significantly decreased in comparison with those of WKY. However no significant differences were observed in DOCA-salt hypertensive rats in the chronic stage. These results indicate that the increase in intracellular free calcium concentration of SHR is not the secondary change caused by high blood pressure. It is impossible to detect the ratio of the three states (open, resting and inactivated) of Ca++ channel. Therefore, there remains a possibility of the changes in the ratio of the states of Ca++ channel. The observed abnormalities of Ca++ regulation may contribute to the pathogenesis of hypertension.     

Abnormal glutathione metabolism and increased cytotoxicity caused by H2O2 in human umbilical vein endothelial cells cultured in high glucose medium

Summary To determine whether increased oxidative stress in diabetes mellitus is due to an impaired freeradical scavenger function in endothelial cells, GSH-dependent H₂O₂ degradation in human umbilical vein endothelial cells was studied. The GSH-dependent, NaN₃-uninhibitable H₂O₂-degradation in endothelial cells was reduced by 48% (p <0.001) when the cells were exposed to 33 mmol/l d-glucose vs 5.5 mmol/l d-glucose. This impairment was dependent not only on the d-glucose concentration in the medium but also on d-glucose specific metabolism, since neither 27.5 mmol/l l-glucose nor 27.5 mmol/l d-raffinose had any effect on the peroxide degradation activity. Activation of the glutathione redox cycle by H₂O₂ in cells exposed to high glucose concentrations was attenuated as compared with 5.5 mmol/l d-glucose because of: 1) a 42% decrease (p <0.001) in intracellular NADPH content, and 2) a 34% reduction (p <0.01) in glutathione release into the media. This results in an accumulation of GSSG in the cells following exposure to H₂O₂. Both H₂O₂-evoked ⁵¹Cr-release and H₂O₂-induced endothelial cell damage were significantly (p <0.01) greater in the 33 mmol/l d-glucose group than in the 5.5 mmol/l d-glucose group. These results indicate that the abnormal glutathione redox cycle observed in endothelial cells is induced by high glucose concentrations in the medium, resulting in an impairment of reduced GSH-dependent H₂O₂-degradation. These abnormalities may associate with the increased cellular damage following an exogenous exposure to H₂O₂.Abbreviations GSH Reduced glutathione - GSSG oxidized glutathione - BSO L-buthionine-[S,R]-sulfoximine