[The incidences of virulence genes in Escherichia coli strains from sporadic diarrheal children].

To investigate the incidence of diarrheagenic Escherichia coli among E. coli strains screened by commercially available O-antigen antisera, we used PCR to isolate 8 virulence genes (eae, bfpA, IpaH, LT, ST, VT1, VT2, and aggR) in 184 E. coli strains sampled from sporadic diarrheal children in our district. eae and bfpA are the localized adherence factor genes of enteropathogenic E. coli (EPEC). IpaH is the invasion antigen gene of enteroinvasive E. coli (EIEC), LT and ST are the toxin genes of enterotoxigenic E. coli (ETEC), VT1 and VT2 are the toxin genes of enterohemorrhagic E. coli (EHEC), and aggR is the adherence factor gene of enteroaggregative E. coli (EAggEC). The results were as follows: eae, 7 (3.8%); bfpA, 0 (0%); IpaH, 0 (0%); LT, 0 (0%); ST, 2 (1.1%); VT, 5 (2.7%); aggR, 8 (4.3%). Seven isolates with eae did not have bfpA, and did not show a localized adherence to HeLa cells. Seven of the 8 isolates with aggR showed aggregative adherence to HeLa cells, while their O-serotypes of them were O111:H21 or O111:HUT. Because of the low incidence of the virulence gene, the commercially available O-antigen antisera was not expected to be useful for the screening of diarrheagenic E. coli, except for EHEC and EAggEC. EAggEC may be important as a pathogen of sporadic diarrhea of children as well as EHEC.

Difference in incidence and transmission mode of methicillin-resistant Staphylococcus aureus among surgery, orthopedics, and pediatrics wards: a prospective study at a university hospital.

The incidence and circumstances of colonization by methicillin-resistant Staphylococcus aureus were prospectively investigated. Among 404 patients, 15 (3.7%) were carriers on admission, and 43 (10.6%) became colonized, mainly after surgical operation. A different mode of transmission was suggested in each ward.

Molecular typing of the methicillin resistance determinant (mec) of clinical strains of Staphylococcus based on mec hypervariable region length polymorphisms.

We used a method for molecular typing the methicillin resistance determinant (mec) based on the size of the mec-associated hypervariable region amplified by the polymerase chain reaction (PCR) to examine 61 methicillin-resistant Staphylococcus aureus (MRSA), 15 methicillin-resistant (Mcr) S. epidermidis, and 11 Mcr S. haemolyticus clinical isolates. In the 61 MRSA isolates, five sizes of PCR products were observed. The MRSA isolates were grouped into five hypervariable region (HVR) genotypes on the basis of the size of the PCR product. Three different sizes were detected among 15 isolates of Mcr S. epidermidis and two sizes among 11 isolates of Mcr S. haemolyticus. The PCR products amplified from 14 of 15 Mcr S. epidermidis isolates were the same as products amplified from MRSA isolates, which was confirmed by the PCR-SSCP (single-strand conformation polymorphism) method. In methicillin-susceptible isolates, the target gene was not amplified. This method is thought to be useful in epidemiologic investigations of nosocomial infections caused by MRSA. This is the first typing method capable of comparing the mec determinants of MRSA isolates and Mcr coagulase-negative staphylococcal isolates to establish the origin of the mec determinant.

[Molecular typing of the methicillin resistance determinant (mec) of clinical strains of Staphylococcus based on mec hypervariable region length polymorphisms].

We used a method for molecular typing of the methicillin resistance determinant (mec) based on the size of the mec-associated hypervariable region amplified by the polymerase chain reaction (PCR) to examine 106 methicillin-resistant Staphylococcus aureus (MRSA), 9 methicillin-resistant (Mcr) S. epidermidis and 5 Mcr S. haemolyticus clinical isolates. In the 106 MRSA isolates, 5 sizes of PCR products were observed. The MRSA isolates were grouped into five hypervariable region (HVR) genotypes on the basis of the size of the PCR product. The PCR products amplified from 8 of 9 Mcr S. epidermidis isolates were the same as products amplified from MRSA isolates, which was confirmed by the PCR-SSCP (single-strand conformation polymorphism) method. In 32 methicillin-susceptible isolates, the target gene was not amplified. This method is thought to be useful in epidemiological investigations of nosocomial infections caused by MRSA. This is the first typing method capable of comparing the mec determinants of MRSA isolates and Mcr CNS isolates to establish the origin of the mec determinant.

A case of myocardial infarction showing extensive precordial ST elevation induced by second diagonal branch occlusion.

We observed a case of acute myocardial infarction induced by second diagonal branch occlusion. Electrocardiogram (ECG) on admission showed ST elevation in leads I, aVL and V2-6. Since emergency coronary angiography disclosed complete occlusion of the second diagonal branch, intra-coronary thrombolysis (ICT) was performed, superselectively. Transient coronary reperfusion was obtained, however, reocclusion occurred after several minutes. Rescue percutaneous transluminal coronary angioplasty (PTCA) was then performed immediately and blood flow was improved to TIMI grade 2. During these processes, the ST-segment on the ECG changed in leads I, aVL and V2-6 always corresponding to the blood flow of the second diagonal branch. We have not seen a report hitherto in which occlusion of only the second diagonal branch could be a cause of extensive anterior infarction-like ECG changes. Although the mechanism of ECG changes in this patient cannot be clearly explained by conventional concepts, we report this case because it is considered to be very rare.

Relationships between left ventricular mass, left ventricular work and coronary artery size in aortic regurgitation--possible mechanism of myocardial ischemia.

To investigate the relationships between coronary artery size, left ventricular (LV) mass, and LV stroke work in aortic regurgitation (AR), these values were measured in 19 patients with severe AR. Twenty normal subjects and 15 patients with mitral regurgitation (MR) were used as control groups. The coronary area index, i.e., the coronary cross-sectional area divided by body surface area (BSA), was larger in the AR group than in the control groups in all measured sites except for the peripheral left anterior descending coronary artery (LAD) and right coronary artery (RCA). However, the coronary area index divided by the LV mass was significantly smaller in AR and MR patients than in normal subjects. Furthermore, the coronary area index divided by LV stroke work was smaller in AR patients than in MR patients and normal subjects. These results suggest that the coronary blood flow associated with the increased LV mass and stroke work caused by regurgitation was insufficient in patients with severe AR, especially in the area of the LAD. Therefore, the occurrence of myocardial ischemia in patients with severe AR may involve inadequate enlargement of the coronary artery which perfuses the LV, in addition to factors such as decreased coronary perfusion pressure, increased coronary artery resistance and decreased coronary flow reserve.

[Quantitative analyses of the normal throat flora of children with upper respiratory tract infections].

Relationship between the normal throat flora and pathogenic bacteria recovered from the throat in 139 children with upper respiratory tract infections in winter were studied using quantitative analyses. Pathogenic bacteria examined include S. pyogenes, H. influenzae, S. aureus, and S. pneumoniae, and the normal floras include alpha-streptococci, gamma-streptococci, Neisseria species, and Micrococci. Children with S. pyogenes in their throats (S. pyogenes group) were examined with anti-streptococcal antibodies such as anti-streptolysin O, anti-streptokinase, and anti-deoxyribonuclease B. Eighty seven pathogenic bacteria were recovered from 72 children (51.8%) out of 139. S. pyogenes and S. pneumoniae groups showed significantly lower alpha-streptococci and gamma-streptococci in incidence of appearance when compared with children with the no pathogenic bacteria in their throats (no bacteria group). H. influenzae group showed significantly lower gamma-streptococci and higher Neisseria sp. in incidence of appearance compared with the no bacteria group. Positive cases for anti-streptococcal antibodies showed a significantly lower alpha-streptococci in number compared with negative cases for antibodies and the no bacteria group, and a significantly lower gamma-streptococci in incidence of appearance compared with the no bacteria group. These data suggest that the normal throat flora may have a role in prevention of colonization by the pathogenic bacteria in vivo, as were shown in vitro by many authors, and that the quantitative analysis of the normal flora is useful because this methodology might reveal whether the bacteria recovered from the throat show the pathogenicity.

[A case of isolated tricuspid regurgitation associated with persistent left superior vena cava].

We presented a rare case of isolated tricuspid regurgitation (TR) associated with persistent left superior vena cava (PLSVC). A 69-year old female was admitted to our hospital because of arrhythmia and cardiomegaly. Pansystolic cardiac murmur of Levine 2/6 was heard in her Erb's area. Remarkable cardiomegaly was revealed as 78% of cardiothoracic ratio and electrocardiographic findings showed atrial fibrillation. Echocardiographically, obvious dilatation of coronary sinus, right atrium and right ventricle were recognized and left atrium was also dilated moderately. Although results of right cardiac catheterization showed almost normal pressure, remarkable TR of grade IV was registered by Doppler echocardiography. Additional diagnosis of PLSVC drained to dilated coronary sinus was made by venography from the left antecubital vein. But evidence of other cardiac shunt diseases and other abnormalities which might be a cause of TR was negligible. It is reported, in general, that PLSVC drained to coronary sinus occurs asymptomatically, and there is no accepted theory that PLSVC is able to be a cause of TR alone. So, we diagnosed our case as rare isolated TR associated with PLSVC, and because only two such cases are reported in Japanese, we reported it.

Postnephrectomy arteriovenous fistula: a case report.

We report a 57-yr-old woman with severe cardiac failure secondary to postnephrectomy arteriovenous fistula which was successfully removed. A review of the literature shows the rarity of this complication; only 72 cases have been reported in the world literature including 6 cases (including the present case) from Japan. Surgical intervention is generally the treatment of choice from a fistula and provides satisfactory results for cardiac failure which is the major complication of this fistula. A characteristic bruit was observed in all reported cases. Therefore, nonsurgical closure by percutaneous embolization for a small sized shunt may be possible if early diagnosis is obtained by careful auscultation of the loin.

[Left ventricular volume decrease during isovolumic relaxation period in gated blood pool scintigraphy: observations in patients with old myocardial infarction].

We studied left ventricular (LV) volume decrease, namely, the downward displacement of the LV volume curve, during the isovolumic relaxation period on the time-activity curves obtained from gated blood pool scintigraphy in patients with old myocardial infarction (OMI). To evaluate the mechanism and clinical significance of this phenomenon, 113 consecutive patients with OMI undergoing gated blood pool scintigraphy, left ventriculography, and Doppler echocardiography were studied. 1. This phenomenon was observed only in patients with anterior OMI (13 of 51 patients: 25%). Presence (Group I) or absence (Group II) of this phenomenon was examined. 2. On left ventriculography, dyskinetic or aneurysmal wall motion was observed in the anterior or apical region more frequently in Group I (11 of 13 patients: 85%) than in Group II (20 of 51 patients: 39%) (p < 0.001). 3. Doppler echocardiography showed that the presence of abnormal LV reversed flow over 20 cm/sec from the apex to the base during the isovolumic relaxation period is more frequent in Group I (7 of 13: 54%) than in Group II (4 of 51: 8%) (p < 0.001). These results suggested that this blood shift in the left ventricle is attributed to asynchronous LV relaxation occurring simultaneously with LV volume decrease on gated blood pool scintigraphy. In conclusion, this phenomenon suggests the presence of asynchronous LV relaxation.

[Nosocomial infections due to methicillin-resistant S. aureus (MRSA) at the Kagoshima University Hospital (1). Coagulase typing of MRSA].

Nosocomial infection due to MRSA at the Kagoshima University Hospital and their coagulase typing were examined using S. aureus (349 strains) clinically isolated in 1989. The results were as follows: 1) S. aureus consisted of 43.6% of MRSA and 56.7% of Methicillin-sensitive S. aureus (MSSA). 2) MRSAs were recovered most frequently from the specimens from the respiratory tract (47.8%). 3) The isolation of MRSA gradually increased in frequency from January to August; however, that of MSSA did not show a similar tendency. 4) The isolation of MRSA was higher in frequency in the surgical wards, the ICU and the pediatric ward. 5) When classified into 8 coagulase types, MRSAs (133 strains) consisted of only 3 types (54.1% of type II, 32.3% of type VII, and 12.0% of type IV), whereas MSSAs contained all coagulase types. As compared with the results of coagulase typing at other institutions, the incidence of type VII was much more frequent at our hospital. 6) A few coagulase types of MRSA appeared in each ward. Also, type II MRSA strains increased in June and July, and type VII MRSA increased in August. However, MSSA strains did not show any similar tendency.

[Nosocomial infections due to methicillin-resistant S. aureus (MRSA) at the Kagoshima University Hospital (2). Susceptibility to antibiotics].

Susceptibility to antibiotics of 123 MRSA strains isolated at the Kagoshima University Hospital in 1989 was examined. The results were as follows: 1) Susceptibility of MRSA strains was excellent to VCM, MINO, and RFP, followed by IMP, CLDM, and CPFX. However, most strains were resistant to PCG, MPIPC, ABPC, CET, CMZ, CZON, GM, and AMK. 2) Five strains highly resistant to RFP were isolated. Three of these strains were isolated on the ward for tuberculosis. This suggests easy development of resistance to RFP by MRSA. 3) Differences in susceptibility to antibiotics between coagulase type II and type VII strains were examined. The cumulative percentage of type II strains susceptible to CLDM (MICs less than 0.5 microgram/ml) was 15.3%, and that of type VII was 45.2%. Strains resistant to CLDM were more frequently isolated among type II than among type VII strains (p less than 0.001). A similar relationship between strains and antibiotics was also found with EM and CPEX. On the other hand, the cumulative percentage of type II strains susceptible to AMK (MICs less than 25 micrograms/ml) was 89.7%, and that of type VII was 9.7%. Strains resistant to AMK were more frequently isolated among type VII than among type II strains (p less than 0.001).

Remnant valve of inferior vena cava dislodged by Swan-Ganz catheter.

We experienced a rare case of a patient with acute myocardial infarction. It was rare in that a piece of tissue, probably a remnant valve of the inferior vena cava in the right atrium, was dislodged by the Swan-Ganz catheter during a right heart catheterization study in the chronic phase of the disease. As far as we know, no other such case has been reported. Such remnants are considered to be present in 2 to 3% of the general population. Therefore, it is necessary to determine the presence or absence of a remnant before cardiac catheterization and to modify the procedure, such as by changing the catheter's approach, when a remnant is present.

[Methicillin-resistant Staphylococcus aureus infection in the Kagoshima University Hospital--special attention to prevalence in otolaryngological infectious disease].

A retrospective study of the characteristics of MRSA (methicillin resistant S. aureus) in Kagoshima University Hospital and its ENT department was reported. There were 231 samples (104 strains) MRSA in all S. aureus 448 samples from Jan. to Sep. 1989 in Kagoshima University Hospital, in which 58 strains (55.8%) were coagulase type II and 35 strains (33.7%) were type VII. The much more predominant numbers of MRSA were observed in all the cases inpatients clinics in surgery, pediatrics, urology, gynecology and dermatology than internal medicine as well as outpatients clinics. In ENT department of this hospital, only 15.4% of all S. aureus were MRSA. On the other hand, bacteriological survey showed 26% of MRSA out of all S. aureus which were detected at Tokyo clinical research center on otorrhea in the patients with chronic otitis media as multicenter clinical trial of Japan. Two cases involved by MRSA after postoperative administration of many types of antibiotics were also demonstrated. These MRSAs were producing type II coagulase and very high concentrations of MICs to many antibiotics were observed. But these cases were not severe and MINO (minocyclin) or GM (gentamicin) were so effective. The effect of combined therapy of some antibiotics or antimicrobial agents was discussed briefly.