Detection of Legionella Species in Clinical Samples: Comparison of Polymerase Chain Reaction and Urinary Antigen Detection Kits

BACKGROUND

Recently, two excellent methods have been used for the diagnosis of Legionnaires' disease: urinary antigen detection and PCR. The purpose of the present study is to analyze and evaluate the sensitivity and specificity of three different urinary antigen detection kits as well as PCR.

MATERIALS AND METHODS

A total of 148 samples were collected from 33 patients between 1993 and 2004. These consisted of 73 urine samples obtained from 33 patients, 57 serum samples provided by 29 patients, and 18 respiratory tract specimens from 13 patients. Three commercially available kits were used to detect urinary antigen. For the 5S PCR reaction, primers L5SL2 and L5SR84 were used.

RESULTS

Positive results were shown in all patients' urine (representing 79.5% of total samples) using the Binax EIA kit, in 93.9% patients (representing 75.3% samples) using the Binax NOW immunochromatographic kit, and in 90.9% (representing 72.6% samples) using the Biotest EIA kit. Urine samples from 12.1% patients (representing 6.8% of total samples), serum samples from 41.4% patients (representing 35.1% of total samples), and respiratory samples from 84.6% patients (representing 88.9% of total samples) showed positive results with PCR.

CONCLUSION

In testing urine of legionellosis patients, it was suggested that three kits were all valuable tools for diagnosis of legionellosis. Since over one-third of patients' serum samples and most respiratory specimens showed positive results with PCR, the addition of PCR for testing of these samples might be useful, particularly in cases of culture negative and serum antibody negative patients.

[Aeromonas species infection with severe clinical manifestation in okinawa, Japan -association with gas gangrene-]

We experienced two patients having Aeromonas species infection with severe clinical manifestations. The one patient was a 15-year-old high school girl student, who had been healthy in her school life, was admitted to the hospital with a sudden onset of left thigh muscle pain and swelling. She subsequently went into septic shock and died one day after admission. Pathological examination on autopsy revealed massive gas formation, skin bullas and ulcers, and extensive severe soft tissue damage throughout the body. Also, all the specimens, including brain, liver, spleen, thigh muscle, and blood in cardiac cavity, were positive for A. veronii biovar sobria. The other patient was 35-year-old man, who suffered from multiple bone fractures during the work in the harbor. One day after admission, he became febrile and went into septic shock. With the presumptive diagnosis of sepsis and gas gangrene, amputation of left thigh was performed. The exudate and aspirate of the amputated portion were repeatedly positive for A. hydrophila. Through the surveillance in Okinawa, Kagoshima, Miyazaki, and Kumamoto Prefectures, a total of 426 isolates from blood cultures were collected in the period from August, 1999 to February, 2000. Of these, 14 isolates (3.3%) were the species of Aeromonas. Of 14 isolates of Aeromonas, 13 were reported from Okinawa and the remaining one was from Kumamoto. Most patients had underlying diseases, particularly liver diseases including liver cirrhosis. The mortality rate was extremely high at 62.5%, and the patients died in short terms after blood culture became positive. With these, Aeromonas species infection is unique to Okinawa, and positive blood culture for Aeromonas species potentially indicates a high-risk, particularly among the patients with underlying diseases.

[Giant-cell myocarditis without a symptom of heart failure seen in a patient with myasthenia gravis and concurrent Hashimoto's disease]

A 69-year-old Japanese woman initially noticed difficulty in squatting in the last two years, followed by nasal voice, fatiguability in mastication, and blepharoptosis. On admission to our hospital, in addition to these neurological findings, we detected ectopic arrhythmia and Levine II systolic murmur at the apex region, without any subjective symptoms. The serum titer of anti-acetylcholine receptor antibody was elevated to 28 nmol/l (normal: < 0.2), and she responded to repetitive nerve stimulation at a frequency of 3 Hz showing 13% waning, she had positive test for edrophonium administration, and was diagnosed as having myasthenia gravis (MG). There was no thymoma by radiographic examination. She also had Hashimoto's disease confirmed by the laboratory findings. Chest X-p revealed dilatation of the heart, and 24-hour Holter ECG revealed non-sustained ventricular tachcardia (VT). Ventriculography revealed prominent dilatation of the left ventricle and diffuse hypokinetic ventricular wall motility. Endomyocardial biopsy revealed muscle fiber degeneration, cellular infiltration, and scattered multinucleated giant cells, confirming a diagnosis of giant cell myocarditis (GCM). Quadriceps muscle biopsy revealed a small number of muscle fibers with giant nuclei, but no giant cells were seen. Immunological study revealed elevation of CD4/CD8 ratio and memory CD4 cells. Antibody to anti-cardiac and anti-striate muscle were strongly positive in the serum. Four months later, she developed dyspnea on effort and hypoxia, accompanied by severe bradycardia leading to sinus arrest. For acute cardiac deterioration, steroid pulse therapy was started followed by oral predonisolone and azathioprine, which aggravated myasthenic symptoms. The patient was ventilated for respiratory hypercapnia. During immunoabsobent therapy, she developed VT which caused a cardiac arrest, leading to fatal outcome. In case of MG, especially overlapped with other autoimmune diseases, evaluation of cardiac function should be conducted to detect GCM.

[Comparative evaluation of two different formulae of Middlebrook 7H9 broth in a fully automated mycobacteria culture system, MB/BacT; the effect of Tween 80]

Two different formulae of Middlebrook 7H9 broth, one containing Tween 80 [Tween (+) broth] and the other containing vancomycin but not Tween 80 [Tween (-) broth], were evaluated in parallel for a fully automated mycobacteria culture system, MB/BacT(Organon Teknika, Durham, NC, U.S.A.). A total of 586 clinical sputum specimens were digested and decontaminated by the semi-alkaline protease-N-acetyl-L-cysteine-NaOH (SAP-NALC-NaOH). Each part of sample treated was inoculated into the MB/BacT Process Bottle containing the respective Middlebrook 7H9 broth. Culture bottles were incubated in the MB/BacT at 37 degrees C for up to 56 days. Of 586 samples, 110 isolates of Mycobacterium tuberculosis complex and 77 of nontuberculous mycobacteria (NTM) were isolated. The occurrence of false alarm due to breakthrough contamination was 3.2 in Tween (+) broth and 2.9% in Tween (-) broth. Also, the positivities of mycobacteria by the respective culture media were comparable. However, Tween (-) broth could detect positive cultures for mycobacteria, particularly for M. tuberculosis complex at the earlier incubation cycle when compared to Tween (+) broth. The time to detect 50% positive cultures for M. tuberculosis complex was 20.5 days for Tween (-) broth and 34.3 days for Tween (+) broth, respectively. With the results, it was concluded that; Tween (+) broth produced homogeneous mycobacterial growth in culture media, and thus, it was easy to prepare the inoculum directly adjusted to McFarland turbidity to the susceptibility test. However, the present formula of Middlebrook 7H9 broth supplemented with Tween 80 was not enough suitable for the rapid detection of positive cultures and needs some revisions to improve.

[Clinical validation of accuracy of anatomical M-mode measurements: effect of harmonic imaging]

OBJECTIVES

Recent advances in ultrasound technology allow reconstruction of images from stored radiofrequency information and creating of M-mode echocardiograms along an M-mode cursor of any direction (anatomical M-mode echocardiography).

METHODS

The accuracy of the measurements obtained by anatomical M-mode echocardiography was evaluated by comparing the measurements with those by B-mode echocardiography with or without harmonic imaging in 8 normal subjects and 14 patients with cardiac disorders. Measurements used the left ventricular short-axis image in 4 different directions (0 to 6, 3 to 9, 1 to 7 and 5 to 11 o'clock).

RESULTS

Anatomical M-mode and B-mode measurements showed good linear relationships with correlation coefficients of 0.90 to 0.99 in any of the 4 directions. However, measurements in the lateral direction (3 to 9 o'clock) showed larger errors than those in the other directions (p < 0.05). With the use of harmonic imaging, the errors tended to become smaller, although it did not reach statistical significance.

CONCLUSIONS

Anatomical M-mode echocardiography accurately measures the left ventricular internal diameter in any direction except the lateral direction. Harmonic imaging is useful to decrease the errors.

[Application of DNA-DNA hybridization, DDH MYCOBACTERIA 'Kyokuto' to species-identification of mycobacteria grown in Middlebrook 7H9 broth]

A colorimetric DNA-DNA hybridization for the genetic identification of mycobacteria, DDH MYCOBACTERIA 'KYOKUTO' (Kyokuto Pharmaceuticals, Tokyo) was evaluated for the clinical isolates of mycobacteria grown in Middlebrook 7H9 broth of MB/BacT (Organon Teknika, Durham, NC, U.S.A.). When the MB/BacT gave the positive interpretation, 10 ml of Middlebrook 7H9 broth was collected from the bottle. After centrifugation at 3,000 rpm for 10 min, two drops of acetone were added to the pellet, then let it stand for one hour at the room temperature. The air-dried pellet was resuspended in a small volume of distilled water, and proceeded to the identification described. Of 136 clinical isolates of mycobacteria, comprising of 76 M. tuberculosis complex and 60 nontuberculous mycobacteria (NTM), ninety-five (70%) were correctly identified when compared to the reference identification. Thirty (22%) isolates resulted in the unidentified due to negative reaction throughout the test wells, and the remaining 11 (8%) were also unidentified due to low likelihoods. According to the package insert, the DDH MYCOBACTERIA may not be applicable to the isolates grown in Middlebrook broth. However, our test procedure using acetone prior to the extraction of bacterial DNA enables us to directly identify the isolates of mycobacteria grown in Middlebrook 7H9 broth of MB/BacT.

[Activities of antimicrobial agents against 5,180 clinical isolates obtained from 26 medical institutions during 1998 in Japan. Levofloxacin--Surveillance Group]

The surveillance study was conducted to determine the antimicrobial activity of fluoroquinolones (ofloxacin, levofloxacin, ciprofloxacin, tosufloxacin) and other 20 antimicrobial agents against 5,180 clinical isolates obtained from 26 medical institutions during 1998 in Japan. The resistance to fluoroquinolones was remarkable in Enterococci, methicillin-resistant staphylococci and Pseudomonas aeruginosa from UTI. However, many of the common pathogens such as Streptococcus pneumoniae including penicillin-resistant isolates, methicillin-susceptible Stahylococcus aureus, Moraxella catarrhalis, the family of Enterobacteriaceae, Haemophilus influenzae including ampicillin-resistant isolates have been kept to be susceptible to fluoroquinolones. About 90% of P. aeruginosa isolates from RTI were susceptible to fluoroquinolones. In conclusion, the results from this surveillance study suggest that fluoroquinolones are useful in the treatment of various bacterial infections including respiratory infections.

[Evaluation of inoculum density prepared by prompt inoculation system and antimicrobial susceptibility test results by the automated MicroScan WalkAway system]

The Prompt Inoculation System adapted to the susceptibility testing by the automated microbiology system, MicroScan WalkAway (Dade MicroScan Inc., West Sacramento, CA, U.S.A.) was evaluated by determining colony forming units (cfu) per ml of the inocula and by the susceptibility test results obtained through repeated testing of the American Type Culture Collection (ATCC) reference strains described by the National Committee for Clinical Laboratory Standards (NCCLS). The colony forming units per ml of the inocula prepared by the Prompt ranged 2x10++(5) to 2x10(6)++ cfu/ml for the ATCC reference strains, the results indicating that the Prompt gave a higher inoculum density and was more reproducible when compared to the standard turbidity, McFarland adjustment. Also, most inocula prepared from the clinical isolates, comprising the strains of Enterobacteriaceae,no-entericbacilli,staphylococci,enterococci, and streptococci,contained 1x10(6) to 3x10(6) cfu/ml. Although the inocula prepared by the Prompt contained more viable bacterial cells, the outcome results for susceptibility testing by the MicroScan WalkAway were highly acceptable. Four ATCC reference strains were repeatedly tested. Of 540 MIC determinations, 489 (90. 6%) were within the acceptable MIC ranges described by the NCCLS M100-S9, whereas the inocula prepared by the photometric adjustment gave 87.4%. In conclusion, the Prompt inocula were found to give more precise susceptibility test results mostly equivalent to those obtained from inocula prepared by the conventional photometric procedures.

[Multicenter evaluation of broth microdilution test, BrothMIC MTB, to determine minimum inhibitory concentrations (MICs) of antimicrobial agents for Mycobacterium tuberculosis--evaluation of interlaboratory precision and interpretive compatibility with agar proportion method]

A newly developed microdilution antimycobacterial susceptibility test, BrothMIC MTB (Kyokuto Pharmaceutical Industrial Co., Ltd., Tokyo, Japan) to determine minimum inhibitory concentrations (MICs) was evaluated at multisites. The test method utilizes air-dried microplates containing serially diluted antimicrobial agents and the modified Middlebrook 7H9 broth. The eight antimycobacterial agents tested were rifampicin, isoniazid, ethambutol, streptomycin, kanamycin, levofloxacin, sparfloxacin and ciprofloxacin. The test plates were reconstituted by inoculation of 0.2 ml of cell suspensions (6 x 10(5) cells/ml) and were incubated at 36 degrees C in 5% to 10% CO2. The growth endpoints were visually read after 7-day and 10-day incubations. The reproducibility was evaluated with the four reference strains of Mycobacterium tuberculosis, and were compared with the agar proportion method described in the National Committee for Clinical Laboratory Standards (NCCLS) M24-T. Of the 1,022 testings of the reference strains, 1,020 (99.8%) of the MICs read after 7-day incubation fell within 3 log2 dilutions. The growth endpoints read after 7-day and 10-day incubations gave equal MIC ranges for the respective agents. The results obtained by the BrothMIC MTB for 93 clinical isolates of M. tuberculosis compared well with those determined by the NCCLS method with 98% to 99% agreements, except for ethambutol. According to the comparative analysis with the agar proportion method, the interpretive MIC breakpoints to discriminate between the isolates susceptible and resistant against the respective agents were proposed. In conclusion, this newly developed microdilution test for M. tuberculosis is a practical, rapid, quantitative, nonradiometric alternative for the determination of MICs in clinical mycobacteriology laboratories.

[Evaluation of a newly developed broth microdilution test method to determine minimum inhibitory concentrations (MICs) of antimicrobial agents for mycobacteria]

We developed a new broth microdilution antimycobacterial susceptibility test for determination of minimum inhibitory concentration (MICs) using an air-dried microplate containing serially diluted antimicrobial agents and the modified Middlebrook 7H9 broth. The eight agents included were streptomycin (SM), isoniazid (INH), rifampicin (RFP), ethambutol (EB), kanamycin (KM), levofloxacin (LVFX), sparfloxacin (SPFX) and clarithromycin (CAM). Serial dilutions of the agents (128 micrograms/ml to 0.125 micrograms/ml) were prepared in microplates, and were reconstituted by inoculation of 0.2ml of cell suspensions (approximately 3 x 10(5) cells/ml). The test plates were incubated at 36 degrees C in 5% CO2, and the growth endpoints were read visually after 5-day, 7-day and 10-day incubations. Four ATCC reference strains, Mycobacterium tuberculosis, M. avium, M. kansasii and M. intracellulare, were repeatedly tested at three sites. Of 480 determination against eight agents, 455 (94.8%), 470 (97.9%) and 455 (94.8%) of the MICs read after 5-day, 7-day and 10-day incubations fell within 3log2 dilutions, respectively. The MICs gradually elevated during the incubation, however those of 7-day incubation were highly precise and easily determined. A total of 160 clinical isolates of M. tuberculosis and 114 of nontuberculous mycobacteria were tested against eight agents. As for the primary drugs (SM, INH, RFP and EB), most isolates of M. tuberculosis were highly susceptible with MIC90, < or = micrograms/ml. Both LVFX and SPFX were also active. The MICs against nontuberculous mycobacteria distributed in a wide range, and the activities of RFP, LVFX, SPFX and CAM were more potent. These results demonstrate this newly developed test method to be a practical, rapid, quantitative and nonradiometric alternative for the determination of MICs in clinical mycobacteriology laboratories.

Preload and incident angle independent index of left ventricular contractility determined by continuous wave Doppler echocardiography

Although left ventricular dP/dtmax can be accurately assessed using Doppler echocardiography, the fact that Doppler-derived dP/dtmax depends both on preload and Doppler incident angle limits its clinical value. We investigated the clinical usefulness of Doppler-derived (dP/dtmax)/IP (IP, isovolumic pressure), which is known to be relatively insensitive to preload and theoretically independent of the incident angle in 9 subjects. We conclude that Doppler-derived (dP/dtmax)/IP is relatively insensitive to both the incident angle and preload. In addition to its noninvasiveness, these unique features makes it very attractive as a clinical index of ventricular contractility.

[Determination of pyrazinamide susceptibility for Mycobacterium tuberculosis by use of Middlebrook culture media and comparison with results of pyrazinamidase test]

We developed a new test method to determine pyrazinamide (PZA) susceptibility for Mycobacterium tuberculosis in an acidified Middlebrook 7H9 broth (pH6.0), and evaluated in comparison with the agar proportion method of the National Committee for Clinical Laboratory Standards (NCCLS) M24-T and with pyrazinamidase assay. The test method is based on a culture in 4 ml of the modified Middlebrook 7H9 broth containing 100, 200 and 400 micrograms PZA/ml, respectively. First, the cell suspension was adjusted to a McFarland #1 turbidity, and then diluted 1:10. After mixing, 0.1 ml of the diluted cell suspension was inoculated and incubated at 36 +/- 1 degrees C in an ambient air. After 7 day-incubation, the test broth was read in comparison with the growth control. When a significant growth at 100 micrograms PZA/ml or an attenuated growth at 100 micrograms PZA/ml but a significant growth at 400 micrograms PZA/ml were observed, the test isolate was interpreted as being PZA-resistant. When PZA-susceptible and PZA-resistant ATCC reference strains were repeatedly tested, the results obtained were highly precise and accurate. A total of 65 clinical isolates were tested, the results indicating 95.4% of agreements with the agar proportion method and 90.8% with pyrazinamidase assay. There found six discrepant results of 13 resistant isolates; three were susceptible by the agar proportion and all the six were positive by pyrazinamidase assay. Accordingly, we can conclude that, in place of radiometric Bactec System, our newly developed test method is an accurate, practical, rapid and nonradiometric alternative to determine PZA susceptibility for M. tuberculosis in clinical mycobacteriology laboratories.

[Determination of in vitro synergy when amphotericin B is combined with various antimicrobial agents against yeasts by using a colorimetric microdilution checkerboard]

We determined in vitro interactions when amphoteric B (AMPH) is combined with various antimicrobial agents against yeast by using a colorimetric microdilution transfer plate technique, principally based on the current National Committee for Clinical Laboratory Standards (NCCLS) M27-T. An oxidation-reduction dye, sodium resazurin, was used as a color indicator to detect the growth of yeasts, and a standard two-dimensional, two-agent microdilution checkerboard in RPMI 1640 was employed to determine in vitro interactions; synergistic, indifferent or antagonistic. The study included 125 clinical isolates of Candida species and nine reference strains of American Type Culture Collection described in M27-T. Among the 34 antimicrobial agents first tested, polymyxin B (PL), rifampicin (RFP), tetracycline (TC) and erythromycin (EM) showed significant synergism. The fractional inhibitory concentration (FIC) indices of the respective agents were; PL 0.16 to 0.51 (mean, 0.315), RFP 0.13 to 0.56 (0.255), TC 0.06 to 0.75 (0.353) and EM 0.27 to 1.0 (0.550). RFP was the most potent agent, 118 of 125 clinical isolates (94.4%) showing synergism (FIC, < or = 0.5). With these results, we can conclude that several antibacterial agents are potentially effective when combined with AMPH against yeasts, probably due to alteration in the permeability barrier of the surface membrane by AMPH. Antifungal synergism may be promising for more effective, and less toxic therapy, and thus in vivo study will be necessary to determine their clinical significance.

[Laboratory-evaluation of antimicrobial susceptibility testings to detect vancomycin-resistant enterococci]

The emergence and dissemination of vancomycin-resistant enterococci (VRE) emphasizes the need for laboratories to be able to correctly detect them. The study described was conducted to evaluate the test methods presently available in Japan to discriminate between the isolates of VRE and those susceptible (VSE). Among the phenotypic test methods evaluated, an agar screening method which utilized 8 micrograms per ml of vancomycin in Mueller-Hinton agar plate appeared to have a sufficient accuracy. When 23 isolates of vanA positive, 31 of vanB positive, 4 of both positive and 60 of both negative were tested, the sensitivity and specificity to detect VRE were estimated to be 98.3% and 100%, respectively. Also, all the VRE isolates were interpreted as being resistant or intermediate by the E test recently approved in Japan, when the results were read after 48 hr-incubation. Whereas, two disk diffusion tests, Showa disk and NCCLS-based Sensi-disc, were evaluated, but both methods failed to discriminate between VRE and VSE, in particular, between the isolates with vanB positive and negative. The automated system, Vitek GPS-TA produced high frequencies of very major errors; 8.7% for vanA positives and 58% for vanB positives. A total of 1,214 enterococcal isolates from multisite laboratories in Japan, comprising 7 different species, were first tested onto agar screening test plates, but none of isolates represented phenotypic vancomycin resistance. With these results, it can be recommended to detect VRE in clinical microbiology laboratories as follows: First, all the enterococcal isolates will be tested onto the agar screening plates or by the E test. Then, if the isolate is interpreted as being resistant or intermediate, the laboratory should confirm whether it is positive for vanA or vanB by polymerase chain reaction (PCR) specified.

[Estimation of right ventricular contractility by continuous-wave Doppler echocardiography]

The right ventricular dP/dtmax and relatively load-independent index, dP/dtmax/IP (IP: instantaneous pressure difference between the right ventricle and right atrium) can be measured from the tricuspid regurgitant velocity by continuous-wave Doppler echocardiography. The present study investigated these indices as measures of right ventricular contractility. Thirty-one patients were classified into three groups: 11 patients without right ventricular disease (control group), 9 with dilated cardiomyopathy and 1 with hypertrophic cardiomyopathy in the dilated phase (DCM group), and 10 with pulmonary hypertension (PH group). Right ventricular contractility was impaired in both the PH group and DCM group, but dP/dtmax was significantly larger in the PH group compared with the control group and DCM group (519 +/- 113 vs 249 +/- 66 and 234 +/- 78 mmHg/sec, p < 0.01). There was no significant difference between dP/dtmax in the control group and DCM group. dP/dtmax/IP in the PH group was smaller than the control group (31 +/- 8 vs 39 +/- 7/sec, p < 0.05) and larger than the DCM group (22 +/- 12/sec, p < 0.05). Mean New York Heart Association grading was 1.0 in the control group, 3.1 in the DCM group, and 2.8 in the PH group, respectively. Thus, dP/dtmax/IP, noninvasively obtained by continuous-wave Doppler echocardiography, may be a better index for evaluating right ventricular contractility than dP/dtmax.

Left ventricular structural and functional characteristics in patients with renovascular hypertension, primary aldosteronism and essential hypertension

To investigate the effect of different etiologies of hypertension on left ventricular structure and function, we compared echocardiographic findings in 10 patients with renovascular hypertension (35 +/- 9 years), 10 patients with primary aldosteronism (42 +/- 9 years), and 14 patients with essential hypertension (41 +/- 6 years). There were no significant differences among the three groups in age, sex, body surface area, blood pressure, interventricular septal thickness, posterior wall thickness, left ventricular end-diastolic dimension or end-systolic dimension, relative wall thickness, left ventricular mass index, or spectrum of left ventricular adaptation (concentric remodeling, concentric hypertrophy, or eccentric hypertrophy). There were no differences in systolic function or diastolic function, which was assessed in terms of the peak rate of increase in dimension normalized for left ventricular end-diastolic dimension (dD/dt/D), the relaxation time, and the relaxation time to peak velocity of lengthening among groups. Multiple regression analysis showed that the systolic blood pressure was the most important determinant of left ventricular mass index (r = 0.56, P < .01), and that left ventricular mass index was the most important determinant of relaxation time and the relaxation time to peak velocity of lengthening (r = 0.48, P < .01 and r = 0.59, P < .01, respectively). The dD/dt/D was correlated only with left ventricular end-systolic dimension (r = 0.59, P < .01). Our results suggest that blood pressure may be a strong determinant of left ventricular hypertrophy, irrespective of the etiology of hypertension, and that the degree of hypertrophy may be related to left ventricular diastolic dysfunction in hypertensive patients with normal systolic function.

[Recent features of parasites detected from clinical specimens]

It is generally considered that we have already been through with problems caused by various kinds of parasites which had once raged throughout the country. On the contrary to our common concept, we occasionally encounter some kinds of parasites in a laboratory as well as in clinical fields, which have become unfamiliar to us in these days. Parasitic diseases are in the first place, proper and limited to certain local regions, but the present situation has been greatly changed. Nowadays, specific parasites are no longer limited to polluted areas, but also they can be detected in any part of the world owing to facilitated transportations and a promoted international exchange of people. A recent gourmet boom is also one of the causes of infection as seen in anisakiasis. This study was conducted on the investigation of parasites detected from clinical specimens in our laboratory during the period from 1989 to 1993. 1) The following parasites were detected : (1) Strongyloides stercoralis, (2) Giardia lamblia, (3) Diphyllobothrium latum, (4) Schistosoma mansoni, (5) Entamoeba histolytica, (6) Necator americanus, (7) Isospora belli. 2) Strongyloides stercoralis was detected at the highest frequency. This result gives an account of high prevalence of the parasite among the inhabitants in Okinawa. In addition, the agar plate medium method which has been newly adopted has definitely led to far-advanced results for detection of this parasite. 3) Schistosoma mansoni and Necator americanus were found from foreigners one of whom was a Tanzanian and the other was a Dominican. 4) Isospora belli was found from those compromised cases such as ATL and AIDS.

[Evaluation of multiple Pseudomonas aeruginosa strains with different characteristics in clinical specimens; combined results from serotyping, drug susceptibility and enzyme production]

Multiple Pseudomonas aeruginosa strains with different characteristics are occasionally isolated from a clinical specimen. Therefore, more than five isolated colonies of P. aeruginosa obtained at random from each clinical specimen (47 sputa, 18 urine, 10 pus and 8 others). These were investigated for serotype, drug susceptibility to eight antimicrobial agents and productivity of enzymes, such as protease and elastase. The specimens with multiple serotype colonies were shown in 17% of the sputa, 11% of the urine and 10% of the pus. 45.7% of the specimens with single serotype colonies exhibited more than two different patterns of enzyme productivity and so did 47.1% different patterns of drug susceptibility. Single serotype strains of P. aeruginosa with different characteristics of these tests were demonstrated in 81.3% of the urine, 73.6% of the sputum, 50.0% of the pus and 66.7% of others. We conclude that it is important to recognize the possible existence of multiple P. aeruginosa strains with different patterns of the enzyme productivity and drug susceptibility, regardless of single serotype, in clinical specimens.

[Diagnosis of coronary artery dehiscence and pseudoaneurysm after modified Bentall operation by Doppler color flow imaging: a case report]

This 48-year-old man presented with anterior chest and back pain in 1981. He was treated with replacement of the ascending aorta and aortic valve under a diagnosis of dissection of the ascending aorta with severe aortic regurgitation. He underwent modified Bentall reoperation for the dilation of the aortic root in 1991. Postoperative two-dimensional echocardiography was performed because of sustained atrial flutter. An echo-free space was detected between the aorta graft and aorta wrapping on the short-axis view. Doppler color flow imaging revealed blood flow from the left coronary artery graft into the echo-free space. This leakage was suspected to be the cause of the echo-free space. Transesophageal echocardiography was performed to conform this hypothesis, which revealed blood flow from the left coronary artery graft into the echo-free space in systole and flow into the left coronary artery graft from the echo-free space in diastole.

[Nosocomial infection with methicillin-resistant Staphylococcus aureus]

Methicillin-resistant Staphylococcus aureus (MRSA) isolated in our hospital between 1986 and 1989 were mainly examined for their susceptibility to various antibiotics and coagulase types. The isolation frequency of MRSA among S. aureus isolated from clinical specimens has been steadily increasing; 37.8% in 1986, 49.8% in 1987, 60.6% in 1988 and 63.2% in 1989. This trend was particularly noticeable in the specimens associated with the respiratory tracts. The isolation rate of MRSA in the surgery and pediatrics wards was higher than that in the internal medicine ward. More than 80% of MRSA were coagulase type II, which were multi-resistant to penicillins, cephems, aminoglycosides and macrolides, and sensitive to MINO, new quinolones and VCM. These epidemic strains were also isolated from the nose of medical staff and from air samples in the wards. These findings suggest that the hospital environment including the patients and hospital personnel is extensively contaminated with multi-resistant MRSA of coagulase type II. Measures should be taken for prevention and control of nosocomial infection with MRSA in the whole hospital.

[In vitro susceptibilities of clinical isolates of Staphylococcus aureus]

In vitro susceptibilities of 350 strains of Staphylococcus aureus to ampicillin (ABPC), methicillin (DMPPC), cloxacillin (MCIPC), cefazolin (CEZ), cefmetazole (CMZ), cefmenoxime (CMX), latamoxef (LMOX) and 5 non-beta-lactam antimicrobial agents were determined according to the standard method of Japan Society of Chemotherapy. Frequencies of the appearance of resistant organisms (MIC greater than or equal to 12.5 micrograms/ml) to beta-lactam antibiotics were 45% for ABPC, 27% for DMPPC, 11% for MCIPC, 24% for CEZ, 15% for CMZ, 36% for CMX and 51% for LMOX. To non-beta-lactam antimicrobial agents, resistant strains appeared at 31% to gentamicin, 15% to amikacin, 0.6% to minocycline (MINO), 1% to norfloxacin (NFLX) and 65% to fosfomycin (FOM). More than 80% of DMPPC-resistant strains were also resistant to LMOX, CMX, ABPC, FOM, and CEZ, but most of those were susceptible to MINO and NFLX. Incidence of DMPPC-CEZ resistant S. aureus was 23% of the 350 strains tested. As stated above, multiply resistant strains of S. aureus are present throughout different hospitals in Okinawa.

[Mitral regurgitation: detection and quantitative evaluation by two-dimensional Doppler echocardiography]

Mitral regurgitation was detected and quantitatively evaluated using two-dimensional Doppler-echocardiography. The subjects consisted of 74 cases having a variety of heart diseases, who underwent left ventriculography within one week before or after the Doppler study. Among 50 patients with mitral regurgitation confirmed by left ventriculography, the Doppler study detected mitral regurgitant flow signals in 46, for a sensitivity of 92%. Minimal mitral regurgitation in four cases could not be detected by Doppler studies. Twenty-four patients had no mitral regurgitation according to left ventriculography; all but one also had no mitral regurgitation by Doppler study, for a specificity of 96%. In one false positive case, typical mitral regurgitant flow signals were detected in an area localized within the left atrial cavity near the mitral valve orifice. The possibility remains that left ventriculography missed this minimal regurgitation. For quantitative assessment of mitral regurgitation, the following two methods were used. Three long-axis views through the lateral, middle and medial parts of the mitral valve, and a short-axis view at the level of the mitral orifice were imaged via the parasternal approach. The area where mitral regurgitant flow signals were detected was mapped on each cross-sectional echocardiogram, then the distance attained by the regurgitant flow from the mitral valve and the area covered by the regurgitant flow were determined. The maximal distance among the three long-axis views and the sum of the distances in these views was parallel to the severity of mitral regurgitation as assessed by left ventriculography.(ABSTRACT TRUNCATED AT 250 WORDS)

[Noninvasive determination of the ratio of pulmonary to systemic blood flow with two-dimensional Doppler echocardiography: efficacy and limitation]

Noninvasive determination of the ratio of the pulmonary to systemic blood flow (Qp/Qs) was attempted in 31 cases with intracardiac shunt using two-dimensional pulsed Doppler echocardiography. The Qp/Qs of these cases was ranged from 0.99 to 4.55 with an average of 2.63 by cardiac catheterization. Technical problems in the measurement were also studied. Seventeen cases with no shunt were served as controls. Systemic and pulmonary flow volumes, Qp and Qs (ml/min), were calculated by the following equation: Q (ml/min) = mean flow velocity (cm/sec) X cross sectional area of the semilunar valve ring (cm2) X 60 Here, the sample volume was set in the center of the valve ring at the phase when the flow velocity attained its peak in a pulse period. The mean velocity was obtained by dividing the integration of instantaneous mean frequency in the sample volume for a pulse period by RR interval. The ultrasonic incident angle was measured on the echocardiogram. The velocity profile at the valve ring was assumed to be a plane wave. The diameter (D) of the valve ring was measured on the echocardiograms of the long-axis view of the outflow tract. To make a correction referring to the value obtained by angiocardiography, 0.22 cm was added to the value obtained on the echocardiogram (D). The cross sectional area of the valve ring was calculated according to the following formula: Cross sectional area (cm2) = pi X [(D + 0.22/2)]2 The Qp/Qs ratio by the Doppler method in the cases with no intracardiac shunt was 1.11 (S.D. = 0.21) on an average and the Qp/Qs in the cases with an intracardiac shunt was well correlated with that by catheterization (r = 0.82). These results suggested the feasibility of the clinical application of the Doppler method for noninvasive determination of Qp/Qs. In 17 cases, pulmonary and systemic flow volumes measured by the direct Fick method were compared with those by the Doppler method, respectively. Considerable differences were observed between them. There was a tendency that both pulmonary and systemic flow volumes were under-estimated by the Doppler method in cases with a large shunt.(ABSTRACT TRUNCATED AT 400 WORDS)

Augmentation of atrial contribution to left ventricular inflow with aging as assessed by intracardiac Doppler flowmetry

The influence of aging on the left ventricular (LV) function in diastole was investigated from the aspect of the mitral inflow pattern using 2-dimensional Doppler echocardiography. The subjects for the investigation were 69 persons who were diagnosed as healthy by a checkup examination. The peak velocity in the rapid filling phase and that in the atrial contraction phase tended to decrease and to increase with aging, respectively. However, these tendencies were not statistically significant. However, the ratio of the atrial contraction phase to the rapid filling phase showed a significant increase with aging (r = 0.82, p less than 0.001). Therefore, it is considered that the mitral flow conditions are influenced by aging. The result obtained is also interpreted to mean that the LV distensibility in early diastole is impaired with aging and that the contribution of the atrial contraction to LV filling is compensatorily augmented.

[Blood flow analysis with pulsed echo Doppler cardiography in valvular pulmonary stenosis (author's transl)]

Blood flows in the main pulmonary artery, right pulmonary artery and right ventricular outflow tract were analyzed in 11 cases of valvular pulmonary stenosis and 10 healthy subjects by pulsed echo Doppler cardiography (two-dimensional) with the parasternal and suprasternal approaches. 1) The systolic flow in the right pulmonary artery was detected in 7 cases of valvular pulmonary stenosis, in which the flow of both right and main pulmonary arteries was detected in only one case. The flows seemed to be turbulent. These abnormal signals were never detected in healthy subjects and considered to be caused by the narrowing of the pulmonic orifice. 2) Abnormal flow signals were also detected in the right ventricular outflow tract in patients of pulmonary stenosis. Their features were as follows: (1) A systolic turbulent flow was detected in a case with severe hypertrophy of the wall and narrowing of the lumen of the right ventricular outflow tract. (2) A/S ratio, which is a ratio of the peak velocity in atrial contraction (A) to the peak velocity in systole (S), was larger in cases with pulmonary stenosis than in healthy subjects (p less than 0.05). It was considered that the atrial component in the right ventricular filling was augmented in pulmonary stenosis. (3) The PEP/ET (pre-ejection period/ejection time) of the right ventricle was smaller in cases with pulmonary stenosis than in healthy subjects (p less than 0.05). The ratio exhibited a reverse correlation with the pressure gradient between the right ventricle and pulmonary artery (r = 0.74, p less than 0.025). (4) Acceleration time index, a ratio of the time interval between the upstroke and the peak velocity of ejection flow to the ejection time, as a parameter indicating the time delay of the peak velocity exhibited a significant correlation with the pressure gradient between the right ventricle and pulmonary artery (r = 0.67, p less than 0.05). (5) No correspondence was revealed between the time interval of Q-peak velocity in systole and that of Q-peak intensity of the murmur during systole. It was remained to be clarified.