Isolation of a toxin B-deficient mutant strain of Clostridium difficile in a case of recurrent C. difficile-associated diarrhea

Clostridium difficile-associated diarrhea (CDAD) recurs in approximately 15%-20% of patients after discontinuation of metronidazole or vancomycin therapy. Most recurrences are believed to be endogenous relapses due to the persistence of spores. However, there is evidence that reinfection with a different strain is a cause of recurrence. We report the case of a patient with a history of multiple episodes of C. difficile colitis. The patient, a 56-year-old female, has had 5 years of repeated recurrences, each shortly after discontinuing vancomycin therapy. During the course of these episodes, three isolates were cultured from her stools at different times. These isolates were analyzed for the presence of toxin A and B gene sequences and genotyped by means of arbitrarily primed polymerase chain reaction (AP-PCR). The original two isolates contained the toxin A and B genes, as determined by PCR, and were of the same AP-PCR type. During her last relapse, a C. difficile strain lacking at least a portion of the toxin B gene was isolated. AP-PCR analysis of this isolate showed a different DNA banding pattern from that of the previous isolates. A vancomycin susceptibility assay revealed a slight decrease in vancomycin activity as compared with that against the prior isolate. This case demonstrates two unique features: (1) recurrent infections can be due to reinfections and (2) toxin B mutants can possibly cause CDAD. This study also raises concerns about long-term vancomycin use and the development of resistance of C. difficile to vancomycin.

Monte Carlo based method for conversion of in-situ gamma ray spectra obtained with a portable Ge detector to an incident photon flux energy distribution

A Monte Carlo based method for the conversion of an in-situ gamma-ray spectrum obtained with a portable Ge detector to photon flux energy distribution is proposed. The spectrum is first stripped of the partial absorption and cosmic-ray events leaving only the events corresponding to the full absorption of a gamma ray. Applying to the resulting spectrum the full absorption efficiency curve of the detector determined by calibrated point sources and Monte Carlo simulations, the photon flux energy distribution is deduced. The events corresponding to partial absorption in the detector are determined by Monte Carlo simulations for different incident photon energies and angles using the CERN's GEANT library. Using the detector's characteristics given by the manufacturer as input it is impossible to reproduce experimental spectra obtained with point sources. A transition zone of increasing charge collection efficiency has to be introduced in the simulation geometry, after the inactive Ge layer, in order to obtain good agreement between the simulated and experimental spectra. The functional form of the charge collection efficiency is deduced from a diffusion model.

Quality care for cardiology patients

To evaluate outcome measures in a cardiology unit, patient satisfaction was measured. Patients consistently related problems in two areas: pain management and the waiting period before their procedure. After a major system change, patient satisfaction increased 16% and 29% respectively.

Pregnancy and birth after intracytoplasmic sperm injection with totally immotile sperm recovered from the ejaculate

OBJECTIVE

To report the birth of two healthy children after intracytoplasmic sperm injection (ICSI) with totally immotile spermatozoa recovered from the ejaculate.

DESIGN

Retrospective case report.

SETTING

University-based hospital.

PATIENT(S)

Four couples in whom spermatozoa recovered from the ejaculate were totally immotile but presented normal vitality scores.

INTERVENTION(S)

Therapeutical IVF-ET attempts coupled with ICSI.

MAIN OUTCOME MEASURE(S)

Fertilization and pregnancy results after ICSI.

RESULTS

With random sperm injection, 19 of the 36 injected oocytes showed normal fertilization and cleavage. One of four patients had a twin pregnancy that resulted in birth of two healthy children.

CONCLUSION(S)

In cases in which totally immotile ejaculated sperm present normal vitality scores, normal clinical outcomes can be achieved by using the usual random sperm selection during conventional ICSI.

Co-metabolism and microbial growth in the biodegradation of alkylbenzenesulphonates

Two organisms, CCMI507 and CCMI852, degrading undecylbenzenesulphonate (LAS) by the ortho- and meta-cleavage pathways were studied in cultures where glucose was used as carbon and energy source. CCMI507 (ortho-pathway) started the degradation of LAS at the beginning of the culture development in parallel with glucose utilization. The degradation followed a steady profile of degradation until 77% of LAS was degraded in the culture containing initially 5 mg l-1 of the compound and 81% in the cultures containing initially 10 and 20 mg l-1 of LAS, after 72 h fermentation. The organism CCMI852 (meta-pathway) started degrading the compound only after 20 h, when 75% of glucose was spent and well within the stationary-phase. After 72 h fermentation the level of degradation by CCMI852 varied from 70% (5 mg l-1 of LAS) to around 75% (10 and 20 mg l-1 of LAS).

Isolation of various genotypes of Clostridium difficile from patients and the environment in an oncology ward

The epidemiology of Clostridium difficile-associated diarrhea (CDAD) is not well defined in nonepidemic situations because precise biotyping techniques have only recently become available. Arbitrarily primed polymerase chain reaction (AP-PCR) was used to determine strain identity of C. difficile isolates recovered on our oncology ward, at an incidence rate of 0.84%. Twenty-one strains of C. difficile, which were grouped into 18 different AP-PCR types, were isolated from patients' specimens. Forty-two C. difficile isolates recovered from the environment (33 toxigenic and 9 nontoxigenic) represented 9 different AP-PCR types. The most commonly found type, a toxigenic strain accounting for 29% of the environmental isolates, was widespread throughout the ward. None of the environmental types were found among the isolates from patients. Three patients' isolates were of the same AP-PCR type, and two of these patients had occupied neighboring rooms at the same time. The diversity of C. difficile isotypes suggests that endemic nosocomial CDAD is not necessarily clonally spread.

A follow-up study of EEG coherences in children with different pedagogical evaluations

A follow-up study on EEG coherence values was carried out with 46 school-age children divided into three pedagogical groups considering their reading and writing abilities (normal subject and children with mild and with serious reading-writing problems). EEGs were recorded at rest, with eyes closed in 15 referential derivations that gave 105 possible coherence values. Coherence was calculated after the elimination of the average reference. Repeated Measure ANOVAs were calculated to evaluate the effects of time, sex, reading-writing problems and their interactions. The second EEG recordings were taken 2-3 years after the first. The results revealed significant increase of coherence values during the time lapse studied, consisting of an increase of frontal coherences in all bands, with the exception of the theta band. The most numerous changes occurred in the alpha band. Very few differences in coherence values were observed between the two EEG recordings by pedagogical groups and by sex suggesting a similar but not igual maturation of coherences of boys and girls and of the three pedagogical groups, in this age range studied. These findings suggests an abnormal coherence development for the reading disabled group, as well as different coherence maturation for boys and girls in this time lapse studied.

Evolution of cerebral edema and its relationship with power in the theta band

In previous papers we have proposed that in patients with space-occupying lesions, delta power was related with the volume of the lesion and theta power with the volume of the edema. In this report we analyze the evolution of 10 patients with space-occupying lesions in whom we measured the volume of the lesion and of the edema before and after treatment that produced changes in these volumes. EEGs were recorded in the leads of the 10-20 system referenced to linked earlobes. Delta and theta powers were calculated for voltage and current source densities (CSD) and compared with age-norms to compute conventional Z-maps. These maps provide probability statements about the deviation of observed values from the norm. Rank correlations between the change in the volume of the lesion before and after treatment and the change in Z-values before and after treatment were significant only in the delta band. However, rank correlations between the change in the volume of the edema and the change in EEG Z-values were only significant in the theta band. These correlations were higher for CSD than for voltage estimates. We also observed that the site of the lesion and of the edema was better represented by CSD maps than by voltage maps. These results are also in agreement with our previous reports, in which we observed more precise localization of brain lesions by CSD than by voltage estimates.

Aging, hyaluronidase removal of the cumulus, and microinjection do not affect the sperm binding potential of human oocytes

PURPOSE

We studied the influence of aging, hyaluronidase removal of the cumulus, and microinjection on the sperm binding potential of human oocytes under intact zona assay conditions to determine the safe use of unstored aged unfertilized ICSI oocytes on zona binding tests. Results were also compared with those for aged IVF oocytes under the same conditions.

METHODS

To avoid the large variation in sperm binding scores, we compared the ratios of the number of sperm bound to nontreated versus to treated oocytes. Treated oocytes were those whose zonae were exposed to hyaluronidase, an agent that decreases sperm binding. Experimental groups were fresh oocytes, experimentally aged fresh oocytes, fresh oocytes whose cumulus was removed either mechanically or with hyaluronidase, aged ICSI oocytes, and aged IVF oocytes.

RESULTS

Statistical analysis within and between groups showed that aging, previous insemination, cumulus removal by hyaluronidase, and microinjection did not affect the sperm binding potential of human oocytes.

CONCLUSIONS

As the zona binding ability of fresh and unfertilized aged ICSI oocytes is similar, they can be used safely in zona assays.

Developmental changes in calcium content of ultrastructurally distinct subcellular compartments of preimplantation human embryos

The ultrastructural localization of mobilizable Ca2+ in different subcellular compartments of human oocytes and preimplantation embryos was studied using the potassium-pyroantimonate technique and transmission electron microscopy; the specificity was confirmed by chelation experiments and X-ray microanalysis. In unfertilized oocytes, Ca2+ was detected in small vesicles beneath the plasma membrane as well as in other forms of smooth endoplasmic reticulum (SER) and in mitochondria but not in cortical granules. In pronuclear zygotes and blastomeres of cleaving embryos, Ca(2+)-rich vesicles were no longer present close to the plasma membrane, and the entire periphery was poor in Ca(2+)-containing organelles which, however, were abundant in the perinuclear region. The uneven Ca2+ loading of SER and mitochondria from the pronuclear stage onwards suggests that Ca2+ release from both these types of organelle contributes to the embryonic Ca2+ signals. During mitosis, less Ca2+ was detected with organelles, but the antimonate reaction product was more abundant in the cytosol. These data suggest that, in addition to different forms of SER, mitochondria also act as a source of mobilizable Ca2+ in preimplantation human embryos. The previously described developmental and cell cycle related changes in the characteristics of Ca2+ signals are associated with the redistribution and structural reorganization of these organelles.

EEG delta activity: an indicator of attention to internal processing during performance of mental tasks

In previous papers we proposed that an increase in delta EEG activity during mental tasks might be related to an increase in subjects' attention to internal processing. In this paper we have made a narrow band analysis to detect those EEG frequencies that change selectively during the performance of a mental task that requires attention to internal processing. Two different experiments were performed: (1) a difficult mental calculation task and a control stimulus with the same physical characteristics as the arithmetical symbols were presented in random order; (2) the Sternberg paradigm for the analysis of short term memory using a memory set of 5 or 3 digits was also presented in random order. Referential recordings to linked ears were obtained in all leads of the 10/20 system. In the first experiment, the increase of power from 1.56 to 5.46 Hz was observed only during the performance of the task and not during the control condition. In the Sternberg paradigm, the increase of power from 1.56 to 3.90 Hz was greater during the difficult than during the easy condition. These results support our hypothesis that an increase in delta activity may be related to attention to internal processing during the performance of a mental task.

A gene map of the human genome

The human genome is thought to harbor 50,000 to 100,000 genes, of which about half have been sampled to date in the form of expressed sequence tags. An international consortium was organized to develop and map gene-based sequence tagged site markers on a set of two radiation hybrid panels and a yeast artificial chromosome library. More than 16,000 human genes have been mapped relative to a framework map that contains about 1000 polymorphic genetic markers. The gene map unifies the existing genetic and physical maps with the nucleotide and protein sequence databases in a fashion that should speed the discovery of genes underlying inherited human disease. The integrated resource is available through a site on the World Wide Web at http://www.ncbi.nlm.nih.gov/SCIENCE96/.

Practice variations in treating urban minority asthmatics in Chicago

This study explores provider adherence to national guidelines in treating Latino and African-American asthmatics. We hypothesized that there would be more variations in asthma treatment existing for minorities as a result of variation in physician's adherent to the guidelines. A 96-item survey was administered to 138 Latino and African-American asthmatics attending a hospital emergency department. Data were obtained on demography, severity, access, patient satisfaction, and patient's assessment of physician asthma management. Results were analyzed by ethnicity, gender, practice site of regular provider, and severity. Variation in physician practice was found in these variables. Asthma treatment received by Latino and African-American respondents was deficient compared to guidelines. Regression analyses showed that Latinos fared more poorly on the number of prednisone bursts taken, use of written crisis plans and dispensation of peak flow meters controlling for gender, practice site and severity. African-Americans expressed less dissatisfaction in obtaining services, while both groups expressed high degrees of satisfaction with their providers.

[Fluorescent products in the crystalline lens of type ii diabetic patients]

A body of evidence suggests that glycation of proteins and the resulting fluorescent products take part in the late complications of diabetes. The purpose of this study was to analyse the fluorescence of lens soluble proteins from diabetic patients. Soluble proteins were obtained from lens with cataract from 20 type II diabetic patients and from 21 non diabetic controls with similar age. The fluorescence of the soluble fraction (EX-360 nm, EM -454 nm) was quantified as a parameter for glycation end products. The glycation of plasma proteins was quantified by fructosamine levels. The fluorescence mean in the group of diabetics was about twice the non diabetic value (p < 0.01). The fluorescence in the diabetics with retinopathy was higher than that of diabetic without retinopathy (p < 0.01). Fructosamine levels were: diabetics 3.1 +/- 1.1 mM, non diabetics 1.9 +/- 0.8 mM (p < 0.001). The results suggest the involvement of fluorescent products, resulting from glycation of proteins, in lens opacification in diabetic patients.

Funguria in cancer patients: analysis of risk factors, clinical presentation and outcome in 50 patients

Fifty cancer patients with funguria of > 10(5) CFU/ml, dysuria and leukocyturia were retrospectively analyzed for etiology, risk factors and outcome. In 72% of cases Candida albicans and in 28% non-albicans Candida spp. (Candida krusei, Candida tropicalis) and non-Candida spp. yeasts (Blastoschizomyces capitatus) were isolated. Torulopsis glabrata was not found among these patients. The most frequent risk factors were: antibiotic therapy with more than one antibiotic agent (96%), concomitant fungal infection in other localizations than the urinary tract (36%), colonization with the same species (48%), catheterization with urinary catheter or nephrostomy (46%), prophylaxis with quinolones (50%) and previous therapy with corticosteroids (72%). Structural or anatomic malformations of the urinary tract (26%), neutropenia (28%), antifungal prophylaxis with azoles (22%), and diabetes mellitus (12%) were less frequently seen. Thirty of 36 patients treated with systemic antifungals were cured and six were not.

[Pancreas divisium as a cause of chronic pancreatitis. Clinical case]

We report a 6 years old girl with chronic pancreatitis, presenting as recurring bouts of abdominal pain and hyperamylasemia, secondary to a lack of communication between the main papilla and pancreatic duct (pancreas divisium). The diagnosis was made during an intraoperative pancreatography and treatment consisted in a sphincteroplasty of the secondary papilla.

Detection of Cryptosporidium parvum DNA in human feces by nested PCR

Cryptosporidium parvum is a coccidian protozoan that causes diarrhea in humans, often chronic and severe in patients with AIDS. Conventionally, diagnosis is made by concentration of stools followed by acid-fast staining (AF) or immunofluorescent staining. The threshold of detection in human stool specimens by these methods may require the presence of 50,000 (immunofluorescent staining) to 500,000 (AF) oocysts per g of stool. In this study, a nested PCR assay was developed to detect C. parvum DNA directly from stool specimens. After extraction of DNA from formalinized stool, a 400-bp fragment of C. parvum DNA was amplified with two 26-mer outer primers. The amplicon from this reaction was amplified with a second primer pair. With these nested primers, a 194-bp DNA fragment was amplified and confirmed as C. parvum DNA by internal probing with an enzyme-linked chemiluminescence system. This PCR-based test allowed the detection of 500 oocysts per g of stool or 100 ng of C. parvum DNA. Studies indicate that the primers utilized are specific for the DNA of C. parvum. DNA sequences were also detected in stool specimens from 4 of 28 patients previously reported negative by AF. In summary, a rapid, sensitive, and specific assay for the detection of C. parvum directly from stool specimens has been developed. This test has the potential for detecting asymptomatic infection, monitoring the response to therapy, and detecting the organism in environmental sources.

Coronary restenosis

Return of angina within 6 months of a catheter-based treatment of coronary artery disease usually reflects restenosis due to an overly aggressive local healing response to the procedure-related arterial injury. The restenotic lesion should be treated aggressively. Patients with preexisting diabetes mellitus, renal failure requiring hemodialysis, and left anterior descending artery lesions should be considered to be at exceedingly high risk for clinically significant restenosis. Exercise testing is indicated for all patients who experience a return of their angina within 6 months of an interventional procedure. Nurse practitioners in the primary care setting may be the first clinicians to hear of the return of angina. Patients should always be reassured that repeat intervention is almost always possible and is generally effective in providing long-term relief. New devices (in particular the Palmaz-Schatz stent) may help reduce the likelihood of restenosis, to the extent that they provide a large acute post-treatment lumen diameter that is more tolerant of intimal hyperplasia without producing significant narrowing. Until adjunctive drug therapy is found that effectively reduces the local tissue response to interventional therapy, all clinicians involved in caring for patients following such procedures will need to be vigilant and knowledgeable about recognizing and treating restenosis.

[Hepatocellular carcinoma. General aspects of diagnosis and treatment]

Hepatocellular carcinoma is the most frequent form of primary hepatic cancer and has a high dissemination capacity. About 90% of tumors develop over a pre-existing cirrhosis but they also may occur in a normal liver. It has a higher frequency among males and 80% of tumors have clinical manifestations. It is associated to hepatitis B and C virus infection, alcoholism, cirrhosis of any etiology, consumption of aflatoxin Bl, oriental race and familial history. Patients are staged using classifications proposed by Okuda, Child-Pugh and the performance status test. Alpha feto protein is useful for diagnosis and follow up Abdominal ultrasound, hepatic scintiscan, angiography with lipiodol, CAT scan and nuclear magnetic resonance have a high diagnostic yield. Non surgical therapeutic alternatives include intratumoral alcoholization, chemoembolization and other such as tamoxifen and monoclonal antibodies. Surgical treatment is based on hepatic resection, whose magnitude depends on hepatic function. Hepatic transplantation is a new therapeutic alternative for patients in whom resection is not feasible and have a single small tumor without metastases.

Subcutaneous tissue oxygen pressure: a reliable index of peripheral perfusion in humans after injury

The usual initial life-threatening effect of injury is hypovolemic shock. In the hierarchical physiologic response to hypovolemia, perfusion of peripheral tissues is sacrificed early and restored late. But the usual hemodynamic and metabolic measurements of blood pressure, urine output, and base deficit are not reliable indices of peripheral perfusion. Although the Clark electrode can quantitate tissue oxygen pressure and thereby serve as an index of perfusion, its use is compromised by several technical deficiencies. Recently, an optical method (optode) using fluorescent technology has been developed for measurement of oxygen tension in subcutaneous tissue (P sgO2). Our studies compared this device with the Clark electrode in the laboratory and tested its value in both animal and clinical studies of hypovolemic shock. The results of these several studies demonstrated that: (1) the new oximeter tracked a rapid fall or rapid rise of oxygen tension between room air (150 mm Hg) and 0 mm Hg ( a glucose oxidase/catalase solution) as well as the Clark electrode without encountering its technical problems; (2) with an acute hemorrhage to 20% of base line, the PsgO2 was found to decline rapidly in parallel with the decline of mean arterial pressure (MAP). Although the MAP rapidly returned to normal after immediate complete return of all shed blood, the PsgO2 did not reach normal levels for at least 2 hours, suggesting persistent peripheral vasoconstriction. (3) Studies in progress suggest that between 35 and 78% of trauma patients (n = 18) adequately resuscitated for hypovolemia b customary criteria have a decreased level of PsgO2 for as long as 60 hours after resuscitation for injury. If care is taken to prevent other causes of catecholamine induced vasoconstriction such as pain, fear, cold, and arterial hypoxia, these several results suggest that a certain number of injured patients are inadequately resuscitated despite the return to normal of conventional hemodynamic measurements. The serial analysis of PsgO2 may assist in managing patients and promote better understanding of the responses to injury.

Clostridium difficile-associated diarrhea and colitis

OBJECTIVES

To review and summarize the status of diagnosis, epidemiology, infection control, and treatment of Clostridium difficile-associated disease (CDAD).

DIAGNOSIS

A case definition of CDAD should include the presence of symptoms (usually diarrhea) and at least one of the following positive tests: endoscopy revealing pseudomembranes, stool cytotoxicity test for toxin B, stool enzyme immunoassay for toxin A or B, or stool culture for C difficile (preferably with confirmation of organism toxicity if a direct stool toxin test is negative or not done). Testing of asymptomatic patients, including those who are asymptomatic after treatment, is not recommended other than for epidemiologic purposes. Lower gastrointestinal endoscopy is the only diagnostic test for pseudomembranous colitis, but it is expensive, invasive, and insensitive (51% to 55%) for the diagnosis of CDAD. Stool culture is the most sensitive laboratory test currently in clinical use, but it is not as specific as the cell cytotoxicity assay.

EPIDEMIOLOGY

C difficile is the most frequently identified cause of nosocomial diarrhea. The majority of C difficile infections are acquired nosocomially, and most patients remain asymptomatic following acquisition. Antimicrobial exposure is the greatest risk factor for patients, especially clindamycin, cephalosporins, and penicillins, although virtually every antimicrobial has been implicated. Cases of CDAD unassociated with prior antimicrobial or antineoplastic use are very rare. Hands of personnel, as well as a variety of environmental sites within institutions, have been found to be contaminated with C difficile, which can persist as spores for many months. Contaminated commodes, bathing tubs, and electronic thermometers have been implicated as sources of C difficile. Symptomatic and asymptomatic infected patients are the major reservoirs and sources for environmental contamination. Both genotypic and phenotypic typing systems for C difficile are available and have enhanced epidemiologic investigation greatly.

INFECTION CONTROL

Successful infection control measures designed to prevent horizontal transmission include the use of gloves in handling body substances and replacement of electronic thermometers with disposable devices. Isolation, cohorting, handwashing, environmental disinfection, and treatment of asymptomatic carriers are recommended practices for which convincing data of efficacy are not available. The most successful control measure directed at reduction in symptomatic disease has been antimicrobial restriction.

TREATMENT

Treatment of symptomatic (but not asymptomatic) patients with metronidazole or vancomycin for 10 days is effective; metronidazole may be preferred to reduce risk of vancomycin resistance among other organisms in hospitals. Recurrence of symptoms occurs in 7% to 20% of patients and is due to both relapse and reinfection. Over 90% of first recurrences can be treated successfully in the same manner as initial cases. Combination treatment with vancomycin plus rifampin or the addition orally of the yeast Saccharomyces boulardii to vancomycin or metronidazole treatment has been shown to prevent subsequent diarrhea in patients with recurrent disease.

An STS-based map of the human genome

A physical map has been constructed of the human genome containing 15,086 sequence-tagged sites (STSs), with an average spacing of 199 kilobases. The project involved assembly of a radiation hybrid map of the human genome containing 6193 loci and incorporated a genetic linkage map of the human genome containing 5264 loci. This information was combined with the results of STS-content screening of 10,850 loci against a yeast artificial chromosome library to produce an integrated map, anchored by the radiation hybrid and genetic maps. The map provides radiation hybrid coverage of 99 percent and physical coverage of 94 percent of the human genome. The map also represents an early step in an international project to generate a transcript map of the human genome, with more than 3235 expressed sequences localized. The STSs in the map provide a scaffold for initiating large-scale sequencing of the human genome.

Comparison of arbitrarily primed PCR with restriction endonuclease and immunoblot analyses for typing Clostridium difficile isolates

Arbitrarily primed PCR (AP-PCR) was used to genotype 26 clinical isolates of Clostridium difficile previously analyzed by immunoblotting (IB) and 20 isolates typed by restriction endonuclease analysis (REA) with HindIII. Two levels of differentiation were achieved with the AP-PCR approach by use of two different arbitrary primers. With the 19-mer arbitrary primer T-7 (first level of differentiation), a good correlation was found between IB and AP-PCR typing. Twenty isolates grouped into six IB types were separated into seven major AP-PCR types. These seven AP-PCR groups were further discriminated into 12 subtypes after genotyping with the arbitrary primer PG-05 (second level of differentiation). The remaining six isolates, all of different IB types, showed a unique and distinct DNA banding pattern with both of the arbitrary primers, T-7 and PG-05. Twenty isolates representing 20 REA types from 15 REA groups were resolved into 13 AP-PCR DNA profiles with the arbitrary primer T-7. A good correlation was found at this level of differentiation between the major REA groups, Y and M, and AP-PCR typing. While AP-PCR with this primer failed to differentiate isolates in REA groups J, G, R, and B, AP-PCR with PG-05 resolved these four isolates into four distinct AP-PCR types. In addition, one of three M strains and one of four Y strains displayed a slightly different DNA banding pattern by AP-PCR (with PG-05) from that of the other strains in the group. We conclude that AP-PCR is a rapid and sensitive method which not only complements other typing schemes but also may be a substitute and prove to be especially suited for immediate epidemiological tracking of nosocomial infections due to C. difficile.

Longitudinal quantitative EEG study of children with different performances on a reading-writing test

In a previous paper, using the same test for the evaluation of reading-writing abilities, Harmony et al. (1990b) reported that children with severe difficulties had more delta in fronto-temporal regions, and this was interpreted as a sign of underlying cerebral dysfunction. Children with severe and minor difficulties in the test had more diffuse theta absolute and relative powers and less alpha relative power. As theta decreases with age, while alpha increases, these results suggested that children with minor and severe difficulties in reading had a maturational lag with respect to those with normal performance. We conducted this study in order to test this hypothesis. Two different EEG records were obtained with an interval of 2.58-3.15 years in 49 children classified in 3 groups according to their performance in a reading-writing test. Group 1: adequate performance for age and degree (control group); group 2: below level performance with minor difficulties; and group 3: below level performance, with severe difficulties. The mean age of the groups in the first study was 9 years. Absolute (AP) and relative powers (RP) in the delta, theta, alpha and beta bands were computed for each session. In general, groups 3 and 2 showed greater changes than group 1 from session to session. ANOVAs performed by session clearly demonstrate many significant differences between groups in the first study, while few significant differences in parieto-occipital regions in theta RP were observed in the second session. These results point toward a maturational spurt of children from groups 2 and 3.

Comparison of Z and multivariate statistical brain electromagnetic maps for the localization of brain lesions

Conventional Z maps provide probability statements about the deviation of observed values from the norm. Galán et al. (1994) introduced Simultaneous Significance Probability Scales to detect abnormalities over the whole map, making use of the information provided by the topographic structure of dependencies. They also described multivariate brain electromagnetic (MBE) maps for compact presentation of complex spatio-temporal information. In this paper, using the distance-based localization receiver operating characteristic curves (DL-ROC curves), we compare the localization provided by computed tomography with that provided by Z and MBE maps in 61 patients with brain lesions. Maps were calculated for absolute power and relative power in delta, theta, alpha and beta bands for voltage and current source densities (CSD). In each patient, all maps were compared and the map with the highest value of the area of the DL-ROC curve was considered to be the "best map." Z maps of CSD were the "best maps" in 24 patients. In the voltage montage, we observed that multivariate maps add some information not contained in the Z maps. However, for CSD, Z maps were more accurate than multivariate maps. A very consistent finding was the observation that lesions were better detected by maps analyzing the delta band, while edema was better represented by maps in the theta range.

IgG subtype is correlated with efficiency of passive protection and effector function of anti-herpes simplex virus glycoprotein D monoclonal antibodies

IgG subclasses differ in their effector functions in a variety of in vitro assays. To assess the effect of antibody subclass differences on in vivo protective efficacy against herpes simplex virus (HSV), a series of subclass switch mutants was made from an anti-HSV glycoprotein D monoclonal antibody. Purified antibody was examined for the ability to protect against HSV-2 challenge in mice. IgG2a was found to be more effective than IgG1. This correlated both with activity in antibody-dependent cell-mediated cytotoxicity and with efficiency of complement-mediated neutralization. These data suggest that optimization of passive immunization against HSV requires consideration of antibody subclass.

Clostridium difficile-associated diarrhea and colitis

OBJECTIVES

To review and summarize the status of diagnosis, epidemiology, infection control, and treatment of Clostridium difficile-associated disease (CDAD).

DIAGNOSIS

A case definition of CDAD should include the presence of symptoms (usually diarrhea) and at least one of the following positive tests: endoscopy revealing pseudomembranes, stool cytotoxicity test for toxin B, stool enzyme immunoassay for toxin A or B, or stool culture for C difficile (preferably with confirmation of organism toxicity if a direct stool toxin test is negative or not done). Testing of asymptomatic patients, including those who are asymptomatic after treatment, is not recommended other than for epidemiologic purposes. Lower gastrointestinal endoscopy is the only diagnostic test for pseudomembranous colitis, but it is expensive, invasive, and insensitive (51% to 55%) for the diagnosis of CDAD. Stool culture is the most sensitive laboratory test currently in clinical use, but it is not as specific as the cell cytotoxicity assay.

EPIDEMIOLOGY

C difficile is the most frequently identified cause of nosocomial diarrhea. The majority of C difficile infections are acquired nosocomially, and most patients remain asymptomatic following acquisition. Antimicrobial exposure is the greatest risk factor for patients, especially clindamycin, cephalosporins, and penicillins, although virtually every antimicrobial has been implicated. Cases of CDAD unassociated with prior antimicrobial or antineoplastic use are very rare. Hands of personnel, as well as a variety of environmental sites within institutions, have been found to be contaminated with C difficile, which can persist as spores for many months. Contaminated commodes, bathing tubs, and electronic thermometers have been implicated as sources of C difficile. Symptomatic and asymptomatic infected patients are the major reservoirs and sources for environmental contamination. Both genotypic and phenotypic typing systems for C difficile are available and have enhanced epidemiologic investigation greatly.

INFECTION CONTROL

Successful infection control measures designed to prevent horizontal transmission include the use of gloves in handling body substances and replacement of electronic thermometers with disposable devices. Isolation, cohorting, handwashing, environmental disinfection, and treatment of asymptomatic carriers are recommended practices for which convincing data of efficacy are not available. The most successful control measure directed at reduction in symptomatic disease has been antimicrobial restriction.

TREATMENT

Treatment of symptomatic (but not asymptomatic) patients with metronidazole or vancomycin for 10 days is effective; metronidazole may be preferred to reduce risk of vancomycin resistance among other organisms in hospitals. Recurrence of symptoms occurs in 7% to 20% of patients and is due to both relapse and reinfection. Over 90% of first recurrences can be treated successfully in the same manner as initial cases. Combination treatment with vancomycin plus rifampin or the addition orally of the yeast Saccharomyces boulardii to vancomycin or metronidazole treatment has been shown to prevent subsequent diarrhea in patients with recurrent disease.

Apparent outbreaks of Clostridium difficile-associated diarrhea in horses in a veterinary medical teaching hospital

Intestinal colonization with toxigenic strains of Clostridium difficile was documented in 9 of 10 horses with acute onset diarrhea in a veterinary medical teaching hospital, whereas a similar isolate was detected in only 1 of 23 other horses without diarrhea in the hospital. One horse with diarrhea was infected simultaneously with both C. difficile and Salmonella krefeld. Clostridium difficile was detected by fecal culture on selective medium, confirmed with a latex particle agglutination test, and identified as toxigenic by polymerase chain reaction amplification of toxin A and toxin B gene sequences. Using an arbitrarily-primed polymerase chain reaction, 6 distinct C. difficile isolates were detected in the feces of the 9 affected horses at the time of the outbreak of diarrhea.

[Bladder schistosomiasis. Report of a case]

OBJECTIVES

We report an additional case of schistosomiasis of the urinary bladder, an unusual parasitic infection in our setting, with special reference to the histomorphological findings that permitted its diagnosis.

METHODS

Biopsy was performed via cystoscopy and bladder tissue was obtained from an area in the trigone with an abnormal appearance.

RESULTS

Microscopic examination of the biopsy specimen revealed eggs of the parasite Schistosoma haematobium.

CONCLUSIONS

The present case shows the importance of close collaboration between clinicians and pathologists and the usefulness of cystoscopy for diagnosis in urological patients.

Genomic fingerprinting of epidemic and endemic strains of Stenotrophomonas maltophilia (formerly Xanthomonas maltophilia) by arbitrarily primed PCR

Arbitrarily primed PCR (AP-PCR) was used to type 64 clinical isolates of Stenotrophomonas maltophilia from 60 patients and the hands of one nurse. Forty-seven different patterns were observed, most patients having isolates with unique genomic fingerprints. A single pattern, however, was obtained from six of eight patients involved in an intensive care nursery outbreak, confirming the suspected nosocomial transmission of this microorganism. This strain was also found in four other patients hospitalized at the same time but in different units. AP-PCR typing results had a good correlation with the 49 patterns obtained when the isolates were typed by contour-clamped homogeneous electric field gel electrophoresis. Although AP-PCR is slightly less discriminatory than contour-clamped homogeneous electric field gel electrophoresis, it offers several advantages and should be considered as a practical option for molecular typing during investigations of outbreaks.

EEG activation patterns during the performance of tasks involving different components of mental calculation

In this study we demonstrate the existence of different patterns of EEG activation during the performance of 4 different tasks involving different components of mental calculation in normal subjects. The EEG was recorded in all monopolar leads of the 10/20 system using linked ear lobes as reference. Absolute and relative power were calculated in the delta (1.5-3.5 Hz), theta (3.5-7.5 Hz), alpha (7.5-12.5 Hz) and beta (12.5-19 Hz) bands. The tasks were presented randomly and the EEG segments preceding presentation of the stimulus were considered as the rest corresponding to the task requested by the stimulus. Tasks were of 4 different types, involving number comprehension, recognition of mathematical symbols, the calculation process and the spatial component. ANOVAs between the rest periods showed no differences in any band. Neither did ANOVAs between tasks. However, other variables (task minus rest), which were calculated as the differences in power between task and rest respectively, showed significant differences between tasks in the delta and beta bands in the frontal lobes. In addition, new variables were calculated as the difference between tasks, since many factors were common across several tasks. These variables correspond to the EEG change due to a specific component of mental calculation. Significant differences were obtained in delta and theta bands in right posterior areas and in the beta band in frontal areas. We concluded that the EEG differences observed during different components of mental calculation suggest the participation of different networks.

Electroencephalographic coherences discriminate between children with different pedagogical evaluation

The relationship of reading-writing ability and EEG coherences was studied in 84 subjects from two age groups 7.0-8.9 and 9-11.2 years old. All children were divided into three groups according to their performance on a pedagogical test: ped1, normal children; ped2, children with mild problems; ped3, children with reading-writing disability. The following results were obtained: in general, children showed higher coherences in groups with poor performance in the delta, theta and beta bands. In the alpha band, higher coherence values were related to better performance. The exceptions to this general pattern were rare. Group ped2 had higher coherences in delta, theta and alpha bands than ped1 and ped3, in left temporal leads. In older children the same tendency was observed, but group differences in the theta, alpha and beta bands were few. In this age range, the significant group differences were almost all interhemispheric coherences. The discriminant analysis that classified subjects by their coherence values gave very good results, fact that demonstrates, that EEG coherence is a highly sensitive measurement indicating not only the existence of a reading-writing problem, but also the degree of its severity.

[Hospital prevalence of kidney failure. Consequences and reflections for the planning of nephrology services]

A prospective prevalence study of Renal Failure (RF) in inhospital patients (creatinine > = 1.7 mg/dl) was carried out during March 1994, in two hospitals covering well defined and mutually exclusive populations. Cases were selected by screening all urea and creatinine blood tests performed in both laboratories, and registered in an individual form for daily follow-up of their nephrologic outcome. We registered 242 RF cases among 3525 patients admitted (6.8%), with an A.R.F. prevalence of 5.2%, 46% of all patients had a serum creatinine > 3 mg/dl and 71% were older than 65 years. In 55% RF was acquired inside the hospital. The most frequent cause of A.R.F. was pre-renal failure with 37%, followed by 32% of ischemic acute tubular necrosis and 13% toxic ATN. Nephrology was consulted in only 29% of all hospital RF cases. Only 17% of the RF patients were submitted to dialysis procedures, overall mortality was 31%, and 30% had normal renal function at discharge. Our results provide a data base to rethink the organization, staffing and role of nephrology departments inside general hospitals.

Specific detection of Clostridium difficile toxin A gene sequences in clinical isolates

The polymerase chain reaction (PCR) was used to specifically detect toxin A gene sequences of Clostridium difficile in DNA isolated from human faeces. A set of oligonucleotide primers derived from the non-repetitive region of the toxin A gene was developed to amplify a 634-bp DNA fragment. All 28 cytotoxic strains of C. difficile, previously characterized by a toxin B-PCR assay, were positive for the presence of toxin A gene sequences. No amplification products were obtained from DNAs extracted from non-toxigenic strains, strains of C. sordellii, or C. bifermentans. In addition, amplification of DNA extracted from C. difficile 8864, a strain which does not produce toxin A, resulted in multiple bands which probed negative for toxin A gene sequences. DNAs extracted from nine stool specimens which were positive for toxin B by the cytotoxicity assay and by the toxin B-PCR assay were also positive in this assay. Toxin A gene sequences were detected in DNAs obtained from 4/11 stool specimens which were negative by the toxin B cytotoxicity assay. These four specimens were from patients who had a history of relapses due to C. difficile-associated colitis, and whose stools had previously been found to be positive by the toxin B-PCR test despite no detectable toxin B in the specimens. These data indicate a comparable degree of clinical sensitivity between these two toxin-gene PCR-based assays. This rapid, sensitive and specific assay may be useful not only in the diagnosis of C. difficile infections, but also in molecular studies of the toxin A gene in C. difficile strains.