Magnetic Dipole Transition in

The magnetic dipole transition strength B(M1) of ^{48}Ca is dominated by a single resonant state at an excitation energy of 10.23 MeV. Experiments disagree about B(M1) and this impacts our understanding of spin flips in nuclei. We performed ab initio computations based on chiral effective field theory and found that B(M1: 0^{+}→1^{+}) lies in the range from 7.0 to 10.2 µ_{N}^{2}. This is consistent with a (γ,n) experiment but larger than results from (e,e^{'}) and (p,p^{'}) scattering. Two-body currents yield no quenching of the B(M1) strength and continuum effects reduce it by about 10%. For a validation of our approach, we computed magnetic moments in ^{47,49}Ca and performed benchmark calculations in light nuclei.

Isomeric Excitation Energy for

The excitation energy of the 1/2^{-} isomer in ^{99}In at N=50 is measured to be 671(37) keV and the mass uncertainty of the 9/2^{+} ground state is significantly reduced using the ISOLTRAP mass spectrometer at ISOLDE/CERN. The measurements exploit a major improvement in the resolution of the multireflection time-of-flight mass spectrometer. The results reveal an intriguing constancy of the 1/2^{-} isomer excitation energies in neutron-deficient indium that persists down to the N=50 shell closure, even when all neutrons are removed from the valence shell. This trend is used to test large-scale shell model, ab initio, and density functional theory calculations. The models have difficulties describing both the isomer excitation energies and ground-state electromagnetic moments along the indium chain.

Observation of the Exotic 0_{2}

We report here the first observation of the 0_{2}^{+} state of ^{8}He, which has been predicted to feature the condensatelike α+^{2}n+^{2}n cluster structure. We show that this state is characterized by a spin parity of 0^{+}, a large isoscalar monopole transition strength, and the emission of a strongly correlated neutron pair, in line with theoretical predictions. Our finding is further supported by the state-of-the-art microscopic α+4n model calculations. The present results may lead to new insights into clustering in neutron-rich nuclear systems and the pair correlation and condensation in quantum many-body systems under strong interactions.

Ab Initio Structure Factors for Spin-Dependent Dark Matter Direct Detection.

We present converged ab initio calculations of structure factors for elastic spin-dependent WIMP scattering off all nuclei used in dark matter direct-detection searches: ^{19}F, ^{23}Na, ^{27}Al, ^{29}Si, ^{73}Ge, ^{127}I, and ^{129,131}Xe. From a set of established two- and three-nucleon interactions derived within chiral effective field theory, we construct consistent WIMP-nucleon currents at the one-body level, including effects from axial-vector two-body currents. We then apply the in-medium similarity renormalization group to construct effective valence-space Hamiltonians and consistently transformed operators of nuclear responses. Combining the recent advances of natural orbitals with three-nucleon forces expressed in large spaces, we obtain basis-space converged structure factors even in heavy nuclei. Generally results are consistent with previous calculations but large uncertainties in ^{127}I highlight the need for further study.

Proton Distribution Radii of

The root mean square radii of the proton density distribution in ^{16-24}O derived from measurements of charge changing cross sections with a carbon target at ∼900A MeV together with the matter radii portray thick neutron skin for ^{22-24}O despite ^{22,24}O being doubly magic. Imprints of the shell closures at N=14 and 16 are reflected in local minima of their proton radii that provide evidence for the tensor interaction causing them. The radii agree with ab initio calculations employing the chiral NNLO_{sat} interaction, though skin thickness predictions are challenged. Shell model predictions agree well with the data.

First Report of Seedling Blight of Watermelon Caused by Acidovorax citrulli Transmitted from Rootstock of Pumpkin in China.

Bacterial fruit blotch (BFB) is a devastating disease caused by Acidovorax citrulli, which was first observed in the United States in 1988 (3). A. citrulli can cause severe infection on a wide range of cucurbits, including watermelon, cantaloupe, and pumpkin. Cotyledon symptoms are brown, angular, necrotic spots or large necrotic lesions. The disease is seedborne, so seeds usually serve as the primary inoculum source for BFB outbreaks (2). In July 2012, seedling blight was observed by local farmers from Anhui province in China on watermelon seedlings grafted to pumpkin rootstocks; lesions were morphologically similar to those caused by A. citrulli. Presence of A. citrulli was detected in symptomatic samples by using species-specific primers BX-L1/BX-S-R2 (1). The seed company claimed seeds of watermelon (cv. Changfeng) were certified free of bacterial fruit blotch, but pumpkin seeds (cv. Kangkuxianfeng-1) had not been tested for A. citrulli. For investigating the inoculum source, the remaining seeds of watermelon (cv. Changfeng) and pumpkin (cv. Kangkuxianfeng-1) for seedling production were collected from the farmer and processed for pathogen extraction as described by Walcott and Gitaitis (2). Two microliters of seed wash was used as template for PCR using primers BX-L1/BX-S-R2 (1). The experiment was conducted three times. A 279-bp DNA fragment was consistently amplified by PCR from seed wash of pumpkin seeds, but not from the seed wash of watermelon seeds. Three Acidovorax-like strains (A1, A2, and A3) were isolated from pumpkin seed wash using TWZ semi-selective medium (0.5% peptone, 0.025% CaCl2, 1% Tween-80, 50 mg/liter berberine, 50 mg/liter cycloheximide, 50 mg/liter 2,3,5-triphenyltetrazolium chloride). PCR was performed on the 16S rDNA gene from isolate strain A1, A2, and A3 (1,492 bp; GenBank Accession Nos. JX875533, JX875534, and JX875535) with primers rp1/fd2 (4), and PCR products were sequenced. Results of sequence analysis showed the sequences of strains A1, A2, and A3 were 99% identical to that of the type strain of A. citrulli AAC00-1 (NC_008752). Pathogencity was confirmed by injection of pumpkin cotyledons with bacterial suspensions of each isolate. Collected pumpkin seeds (n = 100 seeds) and watermelon seeds (n = 100 seeds) were planted in plastic pots containing sterilized field soil at room temperature to detect A. citrulli by a wet chamber growing out test. Eight days later, brown, angular, necrotic spots or wilt developed in pumpkin seedlings, but no symptoms were noted on the watermelon seedlings. To our knowledge, this is the first report of A. citrulli causing watermelon seedling blight transmitted from pumpkin seeds by grafting in China. References: (1) O. Bahar et al. Plant Pathol. 57:754, 2008. (2) R. R. Walcott and R. D. Gitaitis. Plant Dis. 84:470, 2000. (3) G. C. Wall et al. Phytopathology 78:1605, 1988. (4) W. G. Weisburg et al. J. Bacteriol. 173:697, 1991.

Extracorporeal membrane oxygenation (ECMO) in patients with COVID-19: a rapid systematic review of case studies.

OBJECTIVE: COVID-19 can cause severe acute respiratory distress syndrome (ARDS). Extracorporeal membrane oxygenation (ECMO) can support gas exchange in patients failing conventional mechanical ventilation, but its role is still controversial. We performed a rapid systematic review focusing on the use of ECMO in patients with COVID-19. MATERIALS AND METHODS: PubMed/MEDLINE, Google Scholar, Embase, the Cochrane Library, EBSCO and Ovid (updated 30 April 2020) were systematically searched. Case reports/Case series from COVID-19 patients treated with ECMO were included in the study. Three reviewers assessed, selected, and abstracted data from studies. All disparate opinions were resolved through discussion. RESULTS: We included 13 articles for systematic evaluation, including 10 case reports and 3 case series studies, with a total of 72 patients. We search for the following information: First author of articles; Patient's location; age; gender; body mass index (BMI); Comorbidities; Time on ECMO; Mode of ECMO; treatments and clinical outcomes. As of all reporting times, our data show that 38 patients (52.8%) have died definitively, 13 patients (18.0%) were still receiving ECMO treatment, 12 patients (16.7%) were alive, 7 patients (9.7%) were recovery and 2 cases (2.8%) remained hospitalized. CONCLUSIONS: ECMO plays an important role in the stabilization and survival critically ill patients with COVID-19, but the usefulness of ECMO in reducing the mortality of severe ARDS caused by COVID-19 was limited. Therefore, a larger sample size study and a comprehensive analysis of evaluating the medical value of using ECMO on COVID-19 patients are urgently required.

MiR-25 overexpression promotes fracture healing by activating the Wnt signaling pathway.

OBJECTIVE: To study the mechanism of micro-ribonucleic acid (miR)-25 in regulating the fracture healing in rats. MATERIALS AND METHODS: A total of 45 male Sprague-Dawley (SD) rats were selected and randomly divided into group A [Phosphate Buffered Saline (PBS), n=15], group B (mimics NC, n=15) and group C (miR-25 mimics, n=15). The fracture model in rats was established via operation in all groups. From 1 d after the successful modeling, 50 µL (2 nmoL) of PBS was intraperitoneally injected into rats in group A, an equal amount of mimics NC was injected into rats in group B, and an equal amount of miR-25 mimics was injected into rats in group C. The above agents were injected once a week for consecutive 6 weeks. Fracture healing in rats was evaluated via X-ray imaging. At the same time, miR-25 expression in the three groups was detected via Reverse Transcription-Polymerase Chain Reaction (RT-PCR). Protein expressions of ß-catenin, proliferating cell nuclear antigen (PCNA) and bone morphogenetic protein-2 (BMP-2) in the three groups were detected via Western blotting. The OCN-, PCNA- and BMP-2-positive osteoblasts in the three groups were detected via immunohistochemical staining and were further quantified. Moreover, the biomechanical properties of femoral fracture healing in the three groups were analyzed via the 4-point bending flexural test. RESULTS: The X-ray examination of the femoral fracture healing at postoperative 1 and 7 weeks revealed that the fracture line disappeared, and both callus formation and fracture healing were good in miR-25 mimics group. In PBS group and mimics NC group, a few fracture lines could be observed, and both callus formation and fracture healing were poor. RT-PCR data showed that the expression level of miR-25 significantly increased in the miR-25 mimics group compared with that in the other two groups, and the differences were statistically significant (p<0.01). Western blotting analyses showed upregulated levels of ß-catenin, PCNA and BMP-2 in the miR-25 mimics group compared with those in the control group, and the differences were statistically significant (p<0.01). Immunohistochemical staining manifested that the numbers of OCN-, PCNA- and BMP-2-positive osteoblasts in miR-25 mimics group markedly increased compared with that in the other two groups (p<0.01), suggesting that osteoblast differentiation in miR-25 mimics group was affected. The above immunohistochemical results indicated that the osteoblast differentiation at the fracture end in miR-25 mimics group was markedly enhanced compared with that in control groups. The results of the biomechanical test of femur specimens at 7 weeks after operation showed that in miR-25 mimics group, the maximum load, fracture energy and stiffness increased by 188%, 333% and 90%, respectively, compared with those in the PBS group (p<0.01). It is indicated that miR-25 promoted the mechanical properties of fracture healing. CONCLUSIONS: The overexpression of miR-25 in the fracture in rats promotes fracture healing by activating the Wnt signaling pathway.

Genetic characterization of rebounding HIV-1 after cessation of highly active antiretroviral therapy.

Despite prolonged treatment with highly active antiretroviral therapy (HAART), infectious HIV-1 continues to replicate and to reside latently in resting memory CD4(+) T lymphocytes, creating a major obstacle to HIV-1 eradication. It is therefore not surprising to observe a prompt viral rebound after discontinuation of HAART. The nature of the rebounding virus, however, remains undefined. We now report on the genetic characterization of rebounding viruses in eight patients in whom plasma viremia was undetectable throughout about 3 years of HAART. Taking advantage of the extensive length polymorphism in HIV-1 env, we found that in five patients who did not show HIV-1 replication during treatment, the rebound virus was identical to those isolated from the latent reservoir. In three other patients, two of whom had been free of plasma viremia but had showed some residual viral replication, the rebound virus was genetically different from the latent reservoir virus, corresponding instead to minor viral variants detected during the course of treatment in lymphoid tissues. We conclude that in cases with apparent complete HIV-1 suppression by HAART, viral rebound after cessation of therapy could have originated from the activation of virus from the latent reservoir. In patients with incomplete suppression by chemotherapy, however, the viral rebound is likely triggered by ongoing, low-level replication of HIV-1, perhaps occurring in lymphoid tissues.

Effects of ovarian ablation or suppression in premenopausal breast cancer: A meta-analysis of randomized controlled trials.

BACKGROUND: The effect of ovarian ablation or suppression (OAS) in premenopausal women with breast cancer is controversial. The overall survival (OS), disease-free survival (DFS) and adverse event of OAS versus no OAS were compared. METHODS: A literature review of EMBASE, Web of Science, PUBMED, and Cochrane Library was conducted. The hazard ratio (HR) and 95% confidence interval (CI) for OS and DFS, as well as risk ratio (RR) and 95% CI for adverse events were evaluated. I-squared statistic (I2) represents heterogeneity. RESULTS: Twenty-nine studies with a total of 21,249 women were included. In premenopausal women aged 40 years or younger, there were significant differences in OS (HR 0.78, 95% CI: 0.66-0.94, P=0.008, I2 = 0%) and DFS (HR 0.84, 95% CI: 0.73-0.97, P=0.02, I2 = 0%) between OAS and no OAS. In advanced stage breast cancer, a significant difference was found in OS (HR 0.76, 95% CI: 0.60-0.96, P=0.02, I2 = 0%). Patients treated with OAS had more chances to have hot flushes (RR 1.91, 95% CI: 1.62-2.26, P < 0.01, I2 = 0%) and vaginal dryness (RR 1.19, 95% CI: 1.08-1.31, P=0.0003, I2 = 0%). No significant difference in depression (RR 1.28, 95% CI: 0.94-1.74, P=0.12, I2 = 0%). CONCLUSIONS: The study shows that OAS plays a beneficial role in premenopausal women aged 40 years or younger and advanced stage breast cancer. However, OAS is associated with increase in hot flushes and vaginal dryness.

Rapid evaluation of left ventricular volume and mass without breath-holding using real-time interactive cardiac magnetic resonance imaging system.

OBJECTIVES: The purpose of this study was to validate cardiac measurements derived from real-time cardiac magnetic resonance imaging (MRI) as compared with well-validated conventional cine MRI. BACKGROUND: Although cardiac MRI provides accurate assessment of left ventricular (LV) volume and mass, most techniques have been relatively slow and required electrocardiogram (ECG) gating over many heart beats. A newly developed real-time MRI system allows continuous real-time dynamic acquisition and display without cardiac gating or breath-holding. METHODS: Fourteen healthy volunteers and nine patients with heart failure underwent real-time and cine MRI in the standard short-axis orientation with a 1.5T MRI scanner. Nonbreath-holding cine MRI was performed with ECG gating and respiratory compensation. Left ventricular end-diastolic volume (LVEDV), left ventricular endsystolic volume (LVESV), ejection fraction (EF) and LV mass calculated from the images obtained by real-time MRI were compared to those obtained by cine MRI. RESULTS: The total study time including localization for real-time MRI was significantly shorter than cine MRI (8.6 +/- 2.3 vs. 24.7 +/- 3.5 min, p < 0.001). Both imaging techniques yielded good quality images allowing cardiac measurements. The measurements of LVEDV, LVESV, EF and LV mass obtained with real-time MRI showed close correlation with those obtained with cine MRI (LVEDV: r = 0.985, p < 0.001; LVESV: r = 0.994, p < 0.001; EF: r = 0.975, p < 0.001; LV mass: r = 0.977, p < 0.001). CONCLUSIONS: Real-time MRI provides accurate measurements of LV volume and mass in a time-efficient manner with respect to image acquisition.

Accuracy of biplane and multiplane transesophageal echocardiography in diagnosis of typical acute aortic dissection and intramural hematoma.

OBJECTIVES: The purpose of this study was to evaluate the diagnostic accuracy of biplane and multiplane transesophageal echocardiography in patients with suspected aortic dissection, including intramural hematoma. BACKGROUND: Transesophageal echocardiography is a useful technique for rapid bedside evaluation of patients with suspected acute aortic dissection. The sensitivity of transesophageal echocardiography is high, but the diagnostic accuracy of biplane and multiplane transesophageal echocardiography for dissection and intramural hematoma is less well defined. METHODS: We studied 112 consecutive patients at a major referral center who had undergone biplane or multiplane transesophageal echocardiography to identify aortic dissection. The presence, absence and type of aortic dissection (type A or B, typical dissection or intramural hematoma) were confirmed by operation or autopsy in 60 patients and by other imaging techniques in all. The accuracy of transesophageal echocardiography for ancillary findings of aortic dissection (intimal flap, fenestration and thrombosis) was assessed in the 60 patients with available surgical data. RESULTS: Of the 112 patients, aortic dissection was present in 49 (44%); 10 of these had intramural hematoma (5 with and 5 without involvement of the ascending aorta). Of the remaining 63 patients without dissection, 33 (29%) had aortic aneurysm and 30 (27%) had neither dissection nor aneurysm. The overall sensitivity and specificity of transesophageal echocardiography for the presence of dissection were 98% and 95%, respectively. The specificity for type A and type B dissection was 97% and 99%, respectively. The sensitivity and specificity for intramural hematoma was 90% and 99%, respectively. The accuracy of transesophageal echocardiography for diagnosis of acute significant aortic regurgitation and pericardial tamponade was 100%. CONCLUSIONS: Biplane and multiplane transesophageal echocardiography are highly accurate for prospective identification of the presence and site of aortic dissection, its ancillary findings and major complications in a large series of patients with varied aortic pathology. Intramural hematoma carries a high complication rate and should be treated identically with aortic dissection.

New real-time interactive cardiac magnetic resonance imaging system complements echocardiography.

OBJECTIVES: We conducted an initial clinical trial of a newly developed cardiac magnetic resonance imaging (CMRI) system. We evaluated left ventricular (LV) function in 85 patients to compare the clinical utility of the CMRI system with echocardiography, the current noninvasive gold standard. BACKGROUND: Conventional CMRI systems require cardiac-gating and respiratory compensation to synthesize a single image from data acquired over multiple cardiac cycles. In contrast, the new CMRI system allows continuous real-time dynamic acquisition and display of any scan plane at 16 images/s without the need for cardiac gating or breath-holding. METHODS: A conventional 1.5T Signa MRI Scanner (GE, Milwaukee, Wisconsin) was modified by the addition of an interactive workstation and a bus adapter. The new CMRI system underwent clinical trial by testing its ability to evaluate global and regional LV function. The first group (A) consisted of 31 patients with acceptable echocardiography image quality. The second group (B) consisted of 31 patients with suboptimal echocardiography image quality. The third group (C) consisted of 29 patients with severe lung disease or congenital cardiac malformation who frequently have suboptimal echo study. Two independent observers scored wall motion and image quality using the standard 16-segment model and rank-order analysis. RESULTS: CMRI evaluation was complete in less than 15 min. In group A, no significant difference was found between ECHO and CMRI studies (p = NS). In group B, adequate visualization of wall segments was obtained 38% of the time using ECHO and 97% of the time using CMRI (p < 0.0001). When grouped into coronary segments, adequate visualization of at least one segment occurred in 18 of 30 patients (60%) with ECHO and in all 30 patients (100%) with CMRI (p < 0.0001). In group C, adequate visualization of the wall segments was obtained in 58% (CI 0.53-0.62) of the time using echocardiography and 99.7% (CI 0.99-1.0) of the time using CMRI (p < 0.0001). CONCLUSIONS: The new CMRI system provides clinically reliable evaluation of LV function and complements suboptimal echocardiography. In comparison with the conventional CMRI, the new CMRI system significantly reduces scan time, patient discomfort and associated cost.

Rapid diagnosis of tuberculous meningitis by a simplified nested amplification protocol.

We have developed a simplified protocol based on nested polymerase chain reaction (PCR) for early diagnosis of tuberculous meningitis. Using this protocol, we detected the Mycobacterium tuberculosis genome within 24 hours in the CSF of 19 of 21 patients (90%) with clinically suspected tuberculous meningitis. The PCR results were negative in all 79 nontuberculous meningitis controls.

Comparison of polymerase chain reaction and pulsed-field gel electrophoresis for the epidemiological typing of Alcaligenes xylosoxidans subsp. xylosoxidans in a burn unit.

Eighteen isolates of Alcaligenes xylosoxidans subsp. xylosoxidans were collected from clinical specimens of 15 patients in a burn unit and a plastic surgery ward over a 16-month period. Pulsed-field gel electrophoresis and polymerase chain reaction (PCR) were compared for the epidemiologic typing of these 18 isolates and fifteen epidemiologically unrelated strains. These 18 isolates demonstrated an identical fingerprint pattern and were easily distinguished from the 15 epidemiologically unrelated strains by pulsed-field gel electrophoresis typing and both enterobacterial repetitive intergenic concensus and repetitive extragenic palindrome-primed PCR fingerprinting. We conclude that pulsed-field gel electrophoresis analysis of XbaI-digested genomic DNA is a highly discriminatory and reproducible method for epidemiological typing of A. xylosoxidans subsp. xylosoxidans isolates. However, poor resolution due to frequent cutting in the smaller fragments (< 145.5 Kb) may lead to difficulty in interpretation. PCR is a rapid and highly discriminatory, but less reproducible, technique with occasional loss of major bands. The fingerprints produced by repetitive extragenic palindrome primed PCR had more intense bands and were easier to read than those produced by enterobacterial repetitive intergenic concensus-primed PCR in this study.

Antimicrobial susceptibility of clinical isolates of Acinetobacter baumannii.

The in-vitro activity of 18 antimicrobial agents alone or in combination against 248 clinical isolates of Acinetobacter baumannii from Taiwan were tested by agar dilution. The MIC90S of ampicillin, amoxicillin, piperacillin, cefuroxime, cefotaxime, ceftriaxone, gentamicin, and amikacin were at least 128 mu g/ml. Ceftazidime, cefepime, sulbactam, clavulanic acid, and tazobactam presented moderate activity with MIC90S of 32, 16, 16, 32, and 32 mu g/ml, respectively. The increased activity of ampicillin/sulbactam, amoxicillin/clavulanic acid, and piperacillin/tazobactam was due to the intrinsic effect of sulbactam, clavulanic acid, and tazobactam, respectively. Imipenem, meropenem, and ciprofloxacin were the most active antimicrobial agents with MIC90S of 1, 1, and 0.5 mu g/ml, respectively. Nineteen isolates (7.7%) were resistant to all aminoglycosides and beta-lactam antibiotics, except carbapenems and ciprofloxacin. We are concerned about the multidrug resistance of A. baumannii in this study.

Comparison of polymerase chain reaction and pulsed-field gel electrophoresis for the epidemiological typing of Campylobacter jejuni.

Seventeen sporadic Campylobacter jejuni enteritis cases occurred in Taichung City, Taiwan between July 1995 and September 1995. Pulsed-field gel electrophoresis (PFGE) and enterobacterial repetitive intergenic consensus (ERIC-1) primed polymerase chain reaction (PCR) techniques were compared for the epidemiological typing of the 17 C. jejuni isolates. Fourteen distinct PFGE fingerprint patterns were observed. Fifteen distinct PCR fingerprint patterns were demonstrated. Two clusters of isolates (isolates 5 and 6; isolates 10, 11 respectively) were found to be genetically indistinguishable by both methods. In conclusion, we consider that PFGE is a highly reproducible method for determining the relatedness among the C. jejuni isolates in this study, although their limited numbers of restriction fragments may reduce the discriminatory power. Although less reproducible than PFGE typing, ERIC-1 primed PCR can be used as a simple and rapid tool to discriminate different strains of C. jejuni.

Comparison of susceptibility to extended-spectrum beta-lactam antibiotics and ciprofloxacin among gram-negative bacilli isolated from intensive care units.

The in vitro activities of extended-spectrum beta-lactam antibiotics (including piperacillin, cefotaxime, ceftriaxone, ceftazidime, cefepime, imipenem, and meropenems) were assessed and compared with the activity of ciprofloxacin against 366 clinical Gram-negative bacilli isolates from the intensive care units of Taichung Veterans General Hospital. The most prevalent species isolated were Pseudomonas aeruginosa and Acinetobacter baumannii. The activities of ceftazidime, cefepime, imipenem, and meropenem against these isolates were comparable to that of ciprofloxacin. Meropenem was found to be the most potent extended-spectrum beta-lactam antibiotic tested and the MIC50s and MIC90s for most of these multiresistant strains were lower than those of imipenem, ceftazidime, and cefepime, except for Stenotrophomonas maltophilia. The extended-spectrum beta-lactam antibiotics that were still active against S. maltophilia were piperacillin and ceftazidime. More than 50% of Enterobacter spp. were resistant to third-generation cephalosporins and piperacillin, but they remained susceptible to carbapenems and cefepime.

Molecular epidemiology of penicillin-resistant Streptococcus pneumoniae isolated in central Taiwan.

Previous studies have suggested that penicillin-resistant pneumococcal isolates (especially those with MIC > 1 microgram/mL) usually are clonally related. To test this hypothesis, the molecular epidemiology of 29 clinical isolates of penicillin-resistant pneumococci (of which 83% were also resistant to either cefotaxime or ceftriaxone) collected in central Taiwan was investigated by pulsed field gel electrophoresis. Twenty-seven distinct patterns were identified. Our results indicate that an increase in penicillin-resistant S. pneumoniae between April 1993 and June 1994 in central Taiwan is not due to the clonal dissemination of a limited number of epidemic strains.

DNA fingerprinting of Pseudomonas aeruginosa serotype O11 by enterobacterial repetitive intergenic consensus-polymerase chain reaction and pulsed-field gel electrophoresis.

We report the use of pulsed-field gel electrophoresis (PFGE) and enterobacterial repetitive intergenic consensus (ERIC)-based polymerase chain reaction (PCR) to characterize clinical isolates of Pseudomonas aeruginosa serotype O11 collected from an incident of hospital-acquired infection. Both typing techniques differentiated 20 different strain types among seven epidemiologically related isolates and 22 epidemiologically unrelated isolates. There was complete concordance between these two techniques. Our results indicate that the ERIC-based PCR technique represents a rapid and simple means for typing P. aeruginosa serotype O11 with a level of discrimination equivalent to that of PFGE.