Evaluation of an algorithmic approach in comparison with the Illumigene assay for laboratory diagnosis of Clostridium difficile infection.

The following three diagnostic algorithms were evaluated in comparison with the Illumigene assay as a stand-alone test for Clostridium difficile detection: glutamate dehydrogenase antigen screen (GDH) followed by toxin A/B antigen testing (Tox A/B) with the cell cytotoxicity assay for discordant specimens (algorithm 1), GDH followed by the Illumigene (algorithm 2), and GDH followed by Tox A/B with the Illumigene for discordant specimens (algorithm 3). A total of 428 stool specimens submitted to three clinical microbiology laboratories in Manitoba, Canada, for C. difficile detection between June 2011 and April 2012 were included in the study. The prevalence of C. difficile in the stool specimens was 14.7% (63/428) based on toxigenic culture (microbiologic reference standard). The sensitivity and specificity of the Illumigene for C. difficile detection were 73.0% and 99.7%, respectively. The corresponding sensitivities and specificities were 65.1% and 100.0% for algorithm 1, 68.3% and 100.0% for algorithm 2, and 69.8% and 100.0% for algorithm 3. Using algorithm 1, a cell cytotoxicity assay was required for toxin detection in 37% of positive tests, prolonging turnaround time. However, the predictive value of a positive test based on a clinical reference standard (all tests positive or cytotoxigenic culture positive and clinical disease on chart review) was slightly higher with algorithm 1 than with the Illumigene assay as a stand-alone test or as part of an algorithm (algorithms 2 and 3). Based on a reduction in turnaround time, simplicity, and acceptable sensitivity and specificity, we recommend algorithm 2 (screening with the GDH antigen test and confirmatory testing with the Illumigene).

Re-evaluation of rejection criteria for endotracheal tube (ETT) specimens from adult patients.

The purpose of this study was to determine optimal criteria for microbiology laboratory screening of endotracheal tube (ETT) specimens submitted for bacterial culture from adult patients. ETT specimens from adult patients that were received by two microbiology laboratories were prospectively evaluated and subdivided into one of three study arms with the following criteria: <10 squamous epithelial cells (SECs) per low-power field with bacteria seen on Gram staining (arm 1), >10 SECs per low-power field with bacteria seen on Gram staining (arm 2) and <10 SECs per low-power field with no bacteria seen on Gram staining (arm 3). A fourth study arm (>10 SECs per low-power field with no bacteria seen on Gram staining) was planned but this arm was terminated due to the paucity of specimens meeting these criteria. Isolate evaluation was performed using standard microbiology protocols. A limited chart review was undertaken at one of the institutions, only reviewing patients from which a potential pathogen was recovered on culture. In total, 141 ETT specimens were evaluated. A potential respiratory pathogen was recovered from 54, 37 and 10 % of specimens in study arms 1, 2, and 3, respectively (P<0.0001, comparing between arm 1 and arm 3). For the 23 patients included in the chart review from whom a potential pathogen was recovered on culture, respiratory infection was considered to be present in 50 % (6/12) of patients in arm 1, 66.6 % (6/9) of patients in arm 2 and 100 % (2/2) of patients in arm 3. Therapy was rarely altered based on culture results. In this study, the ETT specimens submitted for bacterial culture were of limited benefit to clinicians. The data presented here support the use of an absence of bacteria on Gram staining as a rejection criterion for ETT specimens. The criterion of >10 SECs per low-power field should be further evaluated in a prospective study of patients with an unequivocal clinical diagnosis of pneumonia.

Change in antimicrobial susceptibility of Escherichia coli urinary tract isolates at a single institution over a period of 10 years.

Urinary tract infections are common. Few published studies have demonstrated the change in Escherichia coli urinary isolate antimicrobial susceptibility over time within a given area and (or) population. The purpose of this study was to evaluate the change in susceptibility of E. coli clinical isolates obtained from urine specimens at a single institution over a period of 10 years. The microbiology laboratory information system at St. Boniface Hospital (Winnipeg, Manitoba, Canada) was searched retrospectively from 1 January 2000 to 31 December 2009, for all E. coli isolates from either a midstream or catheter urine source that had susceptibility testing performed. Only one isolate per patient was included during the entire study period. Antimicrobial susceptibility testing was carried out with either a Microscan instrument (pre-April 2004) or a Vitek instrument (May 2004 onwards). In total, 7353 E. coli urinary isolates were included for evaluation. Ciprofloxacin susceptibility declined significantly, from 99% in 2000 to 85% in 2009 (p < 0.0001). A small but statistically significant decline in susceptibility was also observed for ampicillin, cefazolin, trimethoprim-sulfamethoxazole, gentamicin, and nitrofurantoin. These data suggest that certain antimicrobials recommended for the treatment of urinary tract infections (ciprofloxacin, trimethoprim-sulfamethoxazole) may no longer be optimal.

Reprocessing flexible gastrointestinal endoscopes after a period of disuse: is it necessary?

BACKGROUND: Gastrointestinal endoscopy is an integral tool in the evaluation and management of many gastrointestinal and hepatobiliary conditions. Although rare, media reports of infectious complications following gastrointestinal endoscopy persist in this new millennium. With only limited data available, society guidelines continue to suggest that endoscopes undergo a reprocessing cycle before the first patient of the day. This preliminary study aimed to assess the microbiological stability of gastrointestinal endoscopes after high-level disinfection. METHODS: In this multiphase study, four endoscopic retrograde cholangiopancreatography (ERCP) scopes and three colonoscopes were evaluated. In phase 1, endoscopes were assayed after initial high-level disinfection and daily for a period of 2 weeks. In phase 2, this procedure was repeated to confirm phase 1 results. In phase 3, endoscopes were assayed after high-level disinfection and again following a 7-day storage period. RESULTS: In phase 1, 6 of 70 (8.6 %) assays were positive. This involved 4 of 7 (57 %) endoscopes (2 colonoscopes and 2 ERCP scopes) and was limited to the first 5 days of the study. No cultures were positive in phase 2. In phase 3, one endoscope had a positive culture. Positive cultures grew only STAPHYLOCOCCUS EPIDERMIDIS, a low-virulence skin organism. DISCUSSION: With proper disinfection and storage, it appears that reprocessing of gastrointestinal endoscopes is unnecessary after periods of disuse of at least 7 days and possibly up to 2 weeks. Despite recent media reports of infectious complications, society guidelines that recommend more frequent reprocessing seem to lack scientific merit and need to be revisited.

Comparison of the ParaSight-F test and the ICT Malaria Pf test with the polymerase chain reaction for the diagnosis of Plasmodium falciparum malaria in travellers.

Rapid and accurate methods are needed for the diagnosis of imported malaria. The ParaSight-F test and the ICT Malaria Pf test are commercially available kits marketed for the diagnosis of Plasmodium falciparum malaria. Both tests are antigen-capture assays based on the detection of P. falciparum histidine-rich protein 2 in peripheral blood. Using microscopy and a polymerase chain reaction (PCR)-based method as reference standards, we performed a 'blinded' comparison of these assays for the detection of P. falciparum infection in 200 febrile travellers returning from malaria-endemic areas. As determined by PCR and microscopy, 148 travellers had malaria and, of these patients, 54.7% (81/148) were infected with P. vivax only, 31.1% (46/148) with P. falciparum only, 9.5% (14/148) with P. ovale, 0.7% (1/148) with P. malariae, and 4.1% (6/148) had mixed infections. Compared to PCR, the ParaSight-F and ICT Malaria Pf tests had initial sensitivities of 94% and 90% and specificities of 95% and 97%, respectively, for the detection of P. falciparum malaria. When discrepant samples were retested with day 0 and day 1 bloods, the sensitivities improved to 96% and 94%, respectively. The 2 remaining false negative results with the Para-Sight-F test and 2 of the 3 false negative results with the ICT Malaria Pf test occurred in samples with < 100 parasites/microL. The performance of these kits was not significantly different (P = 0.75) and both are simple, rapid, and accurate tests for the detection of P. falciparum infection in the returned traveller.

Antimicrobial susceptibilities of blood culture isolates obtained before and after the introduction of ciprofloxacin.

The in-vitro susceptibilities of 1658 blood culture isolates to ciprofloxacin and 13 other antimicrobial agents were determined, and compared with the results for isolates obtained before and after the availability of ciprofloxacin in 1989. Only six (0.6%) of 995 Enterobacteriaceae were resistant to the fluoroquinolones tested; all of the ciprofloxacin-resistant strains were isolated after 1989 (P = 0.04). No significant increase in ciprofloxacin resistance was found in Pseudomonas aeruginosa or Acinetobacter spp. No resistance to ciprofloxacin was found in 124 Staphylococcus aureus isolates prior to 1989, but five (2.4%) of 208 S. aureus strains recovered after 1989 were ciprofloxacin-resistant (P = 0.16). Rates of resistance to ciprofloxacin and other antimicrobial agents commonly used to treat bacteraemic infections have remained relatively low in this Canadian teaching hospital over the past 16 years.

The use of bacteriophages to differentiate serologically cross-reactive isolates of Klebsiella pneumoniae.

In serological typing of Klebsiella pneumoniae strains from human, equine and environmental sources, the capsular identity of many isolates could not be determined because of serological cross-reactivity. A panel of 91 bacteriophages able to lyse each of the 77 capsular serotypes of K. pneumoniae was isolated and tested for the ability to distinguish between strains in a collection of 17 clinical isolates of K. pneumoniae which exhibited cross-reactivity with two or more capsular type sera. Most isolates could be assigned a capsular type by performing a simple streak test with bacteriophage, although some required the application of an efficiency of plating analysis to discern capsular type. Bacteriophage typing was found to be an effective, inexpensive and clinically practical adjunct to serotyping in distinguishing serologically cross-reactive K. pneumoniae isolates, irrespective of their origin.

[Paradoxical embolism in a patient with aneurysm of the interatrial septum]. / Embolia paradossa in una paziente affetta da aneurisma del setto interatriale.

We report a case of pulmonary embolism complicated by paradoxical cerebral embolism in a patient with atrial septal aneurysm and patent foramen ovale. The patient was a 65-year-old obese woman, admitted because of sudden development of right-sided hemiplegia and dysarthria. In the few days before hospitalization she noted painful edema of the right leg and suffered from increasing dyspnea. Echo-Doppler examination of the venous bed confirmed the clinical suspicion of deep vein thrombosis. A pulmonary scan showed multiple perfusion defects in both lungs. On cerebral computerized tomography there were two non-haemorrhagic infarct zones. Contrast transesophageal echocardiography revealed a type II atrial septal aneurysm with right-to-left shunting through a patent foramen ovale. The patient was treated by warfarin, followed by implantation of a caval filter, with a good outcome. Paradoxical embolism may be more common than currently thought. In cases of pulmonary embolism, a careful check for clinical symptoms indicative of a possible paradoxical embolism should be performed and, consequently, a search for possible atrial septal aneurysm or patent foramen ovale.

[Diagnostic reliability of echography in ureteral lithiasis]. / Attendibilità diagnostica dell'ecografia nella litiasi ureterale.

This article takes into account the diagnostic reliability of ultrasounds (US) in the ureteral lithiasis localisation. A stone has been ultrasonographically localised in 82.3% of 119 patients, this rate rising up to 89.4% in the last 85 consecutive patients. From a clinical point of view, 104 patients presented renal signs, whereas 10 out of them showed an atypical symptomatology, which at first led to a suspicion of acute appendicitis (5), intestinal obstruction (4), acute pancreatitis (1). A stone was accidentally detected in five asymptomatic patients. In 80% of the cases, the stone was situated in the proximal or juxtavesical ureter; in 20%, in the middle or distal ureter. A particular stress is laid in the ultrasonographic follow-up, by which the stone was uncovered in 6 cases, at first considered negative at US. Eight patients had to be referred to treatment with ESWL.

Aorto-caval fistula: a clinical spectrum.

Ten cases of aortocaval fistula (ACF) associated with abdominal aortic aneurysm (AAA) were reviewed. In 5 cases the ACF became apparent after evacuation of the thrombus; only 5 patients presented with features of patent ACF. Four patients in addition presented with extra-caval rupture of the aneurysm. Based on these variables, a classification relating ACF and AAA was developed. In this series all patients were male with a mean aneurysm size of 8.5 cm. All patients required bifurcation grafts for reconstruction. A multifactorial etiology related to enlargement and rupture of all aneurysms seems to apply to ACF. Eight of 10 patients survived. Awareness of this entity and proper preparation allow for successful outcome in the treatment of this condition.

Identification of a human erythrocyte receptor for colonization factor antigen I pili expressed by H10407 enterotoxigenic Escherichia coli.

We have identified a receptor for colonization factor antigen I (CFA/I) pili in human erythrocyte membranes. Erythrocyte binding assays, using whole organisms, suggested that the CFA/I receptor was a glycoprotein containing important sialic acid moieties. Subsequently, human erythrocyte membranes were extracted with lithium diiodosalicylate to obtain a soluble glycoprotein fraction from which to isolate receptors. The extracted material caused agglutination of the CFA/I+ but not the CFA/I- organisms at a protein concentration of 0.5 mg/ml. The CFA/I receptor was identified in iodinated extract by an affinity isolation procedure, using whole bacterial cells. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and autoradiography of the washed, extract-coated H10407 CFA/I+ organisms revealed a band with an apparent molecular weight of 26,000 which was present in the original extract but was not observed on extract-coated H10407 CFA/I- bacteria. The addition of purified CFA/I pili reduced binding of the 26,000-molecular-weight receptor to CFA/I+ bacteria. The CFA/I-specific receptor species also bound to wheat germ agglutinin-agarose. This observation supported the suggestion that the CFA/I receptor identified in this report is a sialoglycoprotein.

Location of the antigenic determinants of conjugative F-like pili.

The amino terminus of the pilin protein constitutes the major epitope of F-like conjugative pili studied to date (F, ColB2, R1-19, R100-1, and pED208). Anti-pED208 pilus antibodies were passed through a CNBr-Sepharose affinity column linked to bovine serum albumin which was conjugated to a synthetic peptide, AcP(1-12), containing the major epitope at the amino terminus of pED208 pilin. This allowed the separation of two classes of antibodies; one was specific for the amino terminus and bound to the column, while the other, which recognizes a second epitope on the pilus, did not bind to the column. In addition, antibodies were raised against two amino-terminal peptide-bovine serum albumin conjugates [AcP(1-8) and AcP(1-12)] to ensure a source of pure, high-titer antibodies directed against the amino terminus. The location of these antibodies on intact pili was assayed by immunoelectron microscopy with a protein A-gold technique. The amino terminus-specific antibodies did not bind to the sides of the pili but appeared to be associated with the pilus tip. In addition, these antibodies were found to bind to the vesicle-like structure at the base of the pilus. The anti-pilus antibodies not specific for the amino terminus (unbound immunoglobulin G) were found to bind to the sides of the pilus. Anti-F and anti-ColB2 pilus antibodies bound to the sides of F, ColB2, and R1-19 pili, which have only their secondary epitope in common. The carboxyl-terminal lysine of R1-19 pilin prevents the absorption of anti-F plus antiserum but not anti-ColB2 pilus antiserum to the sides of the pilus, presumably by interfering with the recognition of this secondary epitope.

[Robinow syndrome. Description of a case with diaphragmatic relaxation]. / La sindrome di Robinow. Descrizione di un caso con relaxatio diaframmatica.

The authors report a case of Robinow Syndrome in a child 22 months old, who presented a relaxatio diaphragmatic too. This is the first case, among about twenty cases indicated in literature, in whom this type of malformation is present.

[Experience in educational information for diabetics and their families]. / Esperienza di informazione educativa per il diabetico ed i familiari.

Experience in health education programmes for diabetics is reported. Such education is considered a priority since it is an essential aspect of treatment. Only education can prevent acute attacks and reduce the consequences of later diabetic complications. Elsewhere education programmes have been organised by Anti-diabetic Centres or group meetings. The present health education programme however was conducted at the Day Hospital. The programme was " personalized " to allow for personal control of the disease taking place in the patients' environment and attended not only by diabetics, but also by their families, subjects at risk and non-diabetics interested in this problem.

The parotid and the pancreas.

Parallel studies in parotid and pancreatic function and histology were carried out in Thomas fistula dogs with irradiation-induced chronic pancreatitis. After completion of base line studies of parotid and pancreatic secretion, four dogs were subjected to 2,400 rads tumor dose over two weeks (with a nominal single dose of 1,175 rets); two additional dogs served as control. Sequential studies were performed on pancreatic secretion in response to secretin and on parotid secretion in response to urecholine. After a short-lived period of hypersecretion. There was a progressive reduction in pancreatic secretory rate, bicarbonate and enzyme outputs (greater than 90% after three months). Parotid secretion increased over this period but subsequently decreased, so that at eight months there was a marked reduction both in pancreatic and parotid function. Whereas pancreatic histology showed diffuse interstitial fibrosis and reduction of acinar tissue, no histologic changes were noted in the parotid glands. Although the mechanisms are unclear, alterations in parotid secretion may be of value in the diagnosis of chronic pancreatitis, in the evaluation of its severity, and may yield information on the duration of the disease.