Trends and changes in Clostridium difficile diagnostic policies and their impact on the proportion of positive samples: a national survey.

In June 2012, Israeli guidelines for laboratories were published defining the recommended methods for diagnosis of Clostridium difficile infection (CDI). We conducted this survey to examine the effects of the new recommendations on the proportions of rejected and positive samples by the different methods. A survey was mailed to the directors of all general hospital (GH) and health maintenance organization (HMO) clinical microbiology laboratories. The report was divided into two periods, before and after implementation of the guidelines. Surveys were completed by 13/28 GH laboratories and 5/6 HMO laboratories. All 18 of these laboratories used C. difficile toxin (CDT) enzyme immunoassay alone during the first period of the survey. In the second period, nine laboratories (Group A) used CDT-PCR: two of them used this method exclusively while the other seven used it to resolve most (>90%) of the discrepant results (glutamate dehydrogenase antigen (GDH) +/CDT-]. The other nine laboratories (Group B) used combined GDH/CDT assay, using CDT PCR in only a minority (<20%) of GDH+/CDT- cases. The overall proportion of rejected samples increased from 9.5% in the first period to 13.9% in the second (p<0.001). Between the first and second periods the proportion of positive samples increased from 9.0% to 11.6% in group A laboratories (p<0.001), but decreased from 12.9% to 9.7% in group B laboratories (p<0.001). Implementation of the guidelines has resulted in a significant increase in the proportion of rejected samples and in the proportion testing positive, suggesting more appropriate test utilization and improved sensitivity in the laboratory diagnosis of CDI.

The correlation between Clostridium-difficile infection and human gut concentrations of Bacteroidetes phylum and clostridial species.

We aimed to assess differences in bacterial intensities of Bacteroidetes phylum and different clostridial species in the human intestines with respect to C. difficile infection. Patients with a stool assay for C. difficile toxin were identified via the microbiology laboratory in our institute. Bacterial populations were quantified from stool samples of four groups of patients: Group I-patients with C. difficile associated diarrhea (CDAD); Group II-asymptomatic C. difficile carriers; Group III-patients with non-C. difficile diarrhea; Group IV-patients with no diarrhea and negative stool samples for the C. difficile toxin (control group). Stool was examined for three genes-C. difficile toxin A gene, 16S rRNA gene from Clostridium thermocellum representing other clostridial species, and 16S rRNA gene from Bacteroides fragilis representing the Bacteroidetes phylum. Fifty-nine patients underwent analysis of the stool (CDAD group 14, carriers group 14, non-C. difficile diarrhea group 16, control group 15). C. difficile concentration was highest in the CDAD group, followed by the carriers group. Higher concentrations of both clostridial species and Bacteriodetes were observed in the control and non-C. difficile diarrhea groups compared to the CDAD and carriers groups. We demonstrated an inverse association between infection with C. difficile and the abundance of Bacteroidetes phylum and other clostridial species in human intestines. Studies with larger samples and broader diagnostic procedures are needed in order to better explore and understand this association.

Purification, characterization and preparation immunomatrixes of S-layer proteins of Thermobifida fusca.

AIM: S-layer proteins are considered as a good nanocarrier due to their binding and self-assembled properties. These can be used to prepare the immunomatrixes for the removal of toxins from the samples. METHODS AND RESULTS: Two S-layer proteins 70 and 40 kDa of thermophilic Thermobifida fusca were extracted with guanidine hydrochloride and purified. Antibodies against S-layer proteins were developed, and their monospecificity was checked. Immunogold labelling indicated that these are surface proteins. Immunomatrixes (70-SLIM, 40 SLIM) were prepared by covalently immobilizing S-layer proteins in microwell and further conjugated with anti- Staphylococcus aureus enterotoxin B (SEB) antibodies. The binding of 70 and 40 kDa proteins was observed nearly 7·0 µg cm(-1) to binding area, and the conjugation with anti-SEB antibodies was found 1·22 µg µg(-1) of 70 kDa and 0·875 µg µg(-1) of 40 kDa. The average binding and elution of pure SEB toxin on 70-SLIM and 40-SLIM was 5·0 µg SEB toxin. The SEB toxin in milk samples was also removed on immunomatrixes successfully. CONCLUSION: It is the first report, and this study shows that the thermophilic S-layer proteins can be used to prepare the immunomatrixes. SIGNIFICANCE AND IMPACT OF STUDY: Information in this study can be used to design the strategies for the removal of biologically important materials or toxins from samples.

Characteristics of non-typhi Salmonella gastroenteritis associated with bacteremia in infants and young children.

PURPOSE: To characterize the clinical and laboratory manifestations of non-typhi Salmonella gastroenteritis associated with bacteremia in children less than 36 months old. METHODS: The study group included 17 patients, aged 2-34 months, with non-typhi Salmonella gastroenteritis and bacteremia, hospitalized in a tertiary pediatric medical center during the period 1995-2010. Clinical data were collected by medical chart review. Culture-related data were taken from the microbiology laboratory files. The results were compared with an assigned, age-matched, control group of 17 infants hospitalized with non-typhi Salmonella gastroenteritis without bacteremia. RESULTS: Eleven cases (65%) occurred during the summer season. All patients presented with diarrhea, usually mixed with blood or mucus (clinical dysentery 65%). All but one had a high-grade fever (average 39.5°C). Three patients (19%) experienced convulsions during the acute episode of gastroenteritis. None of the patients had been previously treated with antibiotics. The most prevalent Salmonella serotype identified in the stool and blood was group C. Toxic appearance and convulsions on admission were more common among children with non-typhi Salmonella bacteremia, as opposed to those with non-typhi Salmonella gastroenteritis alone. No other epidemiological or laboratory differences were found. CONCLUSIONS: Non-typhi Salmonella gastroenteritis poses a risk of bacteremia not only in infants younger than 3 months of age, but also in children younger than 36 months of age.

Susceptibility of Ureaplasma urealyticum to tetracycline, doxycycline, erythromycin, roxithromycin, clarithromycin, azithromycin, levofloxacin and moxifloxacin.

The in vitro activity of tetracycline, doxycycline, erythromycin, roxithromycin, clarithromycin, azithromycin, levofloxacin and moxifloxacin was tested against 63 clinical isolates of Ureaplasma urealyticum. The minimal inhibitory concentrations (MICs) and the minimal bactericidal concentrations (MBCs) were determined by the broth microdilution method in A7 medium. The MIC(50) and MIC(90) of the tested agents after 24 h of incubation were as follows: tetracycline, 0.5 and 2.0 µg/ml; doxycycline, 0.125 and 0.25 µg/ml; erythromycin, 2.0 and 8.0 µg/ml; roxithromycin, 2.0 and 4.0 µg/ml; clarithromycin, 0.25 and 1.0 µg/ml; azithromycin, 2.0 and 4.0 µg/ml; levofloxacin, 1.0 and 2.0 µg/ml; and moxifloxacin, 0.5 and 0.5 µg/ml, respectively. The MIC values after 24 h and 48 h incubation differed by no more than one dilution for all the agents with the exception of doxycycline (two dilution difference for MIC(90)). Overall, moxifloxacin was the most active agent in vitro against U. urealyticum, with the narrowest difference between MIC and MBC values, followed closely by levofloxacin. Clarithromycin was the most active macrolide.

Are all beta-lactams similarly effective in the treatment of methicillin-sensitive Staphylococcus aureus bacteraemia?

Methicillin-sensitive Staphylococcus aureus (MSSA) is susceptible to many beta-lactams. We compared cloxacillin and cefazolin, the first-line recommended antibiotics, and other beta-lactams in the treatment of MSSA bacteraemia. This was a retrospective cohort study. Included were adult patients with clinically-significant MSSA bacteraemia treated with a beta-lactam that was started within 48 h after blood cultures were taken. We separated between empirical treatment administered to the patient before receipt of final blood culture results and definitive treatment administered thereafter. Univariate and multivariable analyses for 30-day (empirical treatment) and 90-day (definitive treatment) mortality were conducted, including the type of beta-lactam administered to the patient. Five-hundred and forty-one patients were included for the analysis of empirical treatment and 498 patients alive at 7 days were evaluable for definitive treatment. Empirical treatment with cloxacillin or cefazolin (n = 131) was associated with lower 30-day mortality as compared with cefuroxime (n = 98, p 0.058), ceftriaxone or cefotaxime (n = 194, p 0.008) and beta-lactam-beta-lactamase combinations (n = 61, p 0.013), with adjusted odds ratios (OR) for death ranging from 1.98 to 2.68. Definitive treatment with cefazolin (n = 72) was not significantly different from cloxacillin (n = 281); adjusted OR for 90-day mortality 0.91 (95% confidence interval 0.47-1.77). Treatment with cefazolin both in the empirical and definitive periods was not significantly different from cloxacillin; adjusted OR 0.81 (95% confidence interval 0.18-3.62). Treatment of MSSA bacteraemia with cefazolin is not significantly different from treatment with cloxacillin, while treatment with other beta-lactams, including second and third generation cephalosporins, might be associated with higher mortality.

Amplified fragment length polymorphism analysis of human clinical isolates of Mycobacterium haemophilum from different continents.

The role of the species Mycobacterium haemophilum as a pathogenic non-tuberculous microorganism is becoming better defined with the use of specific detection methods. However, epidemiological investigations of this species are still scarce. We analysed the genetic diversity of M. haemophilum by amplified fragment length polymorphism (AFLP) typing and compared isolates from different parts of the world. In total, 128 isolates, including 41 from the USA, 51 from Australia, 28 from Europe and eight from Israel were compared using AFLP methodology. Two restriction enzymes (MseI and EcoRI) and one selective primer were applied and provided a high discriminatory power. Clusters of isolates with identical AFLP patterns, which could indicate a possible common source, were observed from the Netherlands, New York and Australia. No clear clustering on the basis of continental origin was observed; however, types were restricted to geographical areas and not found on other continents. A high genetic stability within the species was demonstrated by the long-term existence of a single type.

Outbreak of Mycobacterium mucogenicum bacteraemia due to contaminated water supply in a paediatric haematology-oncology department.

We describe an outbreak of bloodstream infections due to Mycobacterium mucogenicum involving five patients in a paediatric haematology-oncology ward over a six-month period. Specimens from faucets on the floor indicated that an automatic faucet was the probable source of infection and identity between strains was confirmed using molecular techniques. Levels of chlorine in the water were intermittently low and may have contributed towards bacterial growth. A review of infection control practices revealed that the exit sites of central venous catheters (CVCs) of children were not properly covered during bathing, which may have facilitated CVC colonisation. Replacing the contaminated faucets, optimal water chlorination and proper coverage of the CVC exit site using impermeable dressings terminated the outbreak. This investigation emphasises the three major factors that should be investigated in outbreaks due to a waterborne pathogen: source of the infection, water supply and infection control practices.

Community-acquired Pseudomonas aeruginosa urinary tract infections in children hospitalized in a tertiary center: relative frequency, risk factors, antimicrobial resistance and treatment.

BACKGROUND: The practice of antibiotic prophylaxis against recurrent urinary tract infection (UTI), with hospitalization reserved for severe or complicated cases, has led to changes in the nature and culprit uropathogens of community-acquired (CA), hospital-treated UTI. Characterization of subgroups that need special considerations is crucial. OBJECTIVES: To elucidate the trends and characteristics of CA Pseudomonas UTI in hospitalized children; define the antibiotic susceptibility; determine the appropriateness of the empiric antibiotics used; compare to other causes of UTI in this population; and thereby define predictors for Pseudomonas UTI. METHODS: A prospective clinical and laboratory study from 2001 through 2005. Children with P. aeruginosa UTI were characterized and compared with non-Pseudomonas UTI. RESULTS: Of 351 episodes of culture-proven CA UTI, 28 (8%) were caused by Pseudomonas, representing a 2.8-fold increase from our previous study. Pseudomonas UTI was more common in children > 5 years (p < 0.01), with urinary abnormalities (p < 0.01) and with previous antibiotic use in the previous month (p < 0.001). Pseudomonas UTI was often resistant to antibiotics usually recommended for empiric therapy; 25% was initially treated with inappropriate IV antibiotics (4.6% in the non-Pseudomonas group, p < 0.001) with 1.3 days longer IV antibiotics. On multivariate analysis, risk factors for Pseudomonas UTI were previous antibiotic therapy and underlying urinary pathology. CONCLUSIONS: Pseudomonas UTI seems to increase in CA, hospital-treated children and is often treated inappropriately according to current treatment protocols. Awareness of this trend and knowledge of the defined risk factors of Pseudomonas UTI might improve the empiric antibiotic therapy.

Pulmonary Mycobacterium simiae infection: comparison with pulmonary tuberculosis.

To identify the clinical and radiological features distinguishing Mycobacterium simiae respiratory infection from pulmonary tuberculosis, the demographics, underlying conditions, and clinical and radiological findings of 121 consecutive patients with pulmonary tuberculosis and 102 with M. simiae respiratory infection were compared retrospectively. In the M. simiae group, the patients were older (mean age 69 +/- 16 years vs. 47 +/- 21 years, p = 0.0001), with a female predominance (62% vs. 45%, p = 0.008). Only 4% were of Ethiopian origin compared to 25% of the tuberculosis group (p = 0.0001). M. simiae infection was associated with significantly higher rates of smoking history, underlying chronic obstructive pulmonary disease, zero human immunodeficiency virus (HIV) infection compared to 10% in the tuberculosis group (p = 0.001), blunted symptoms, and noncavitary infiltrates in the lower/middle lobes on chest X-ray. HIV-negative patients with M. simiae respiratory infection are distinguishable from patients with pulmonary tuberculosis by several demographic, clinical, and radiological features. These findings have important diagnostic and therapeutic implications.

Mortality of patients with antibiotic-associated diarrhoea: the impact of Clostridium difficile.

Previous studies have shown conflicting results concerning mortality related to Clostridium difficile infection. The objective of this study was to determine the impact of C. difficile infection on short- and long-term mortality in hospitalised patients with antibiotic-associated diarrhoea. We therefore undertook a prospective case-control study of 217 hospitalised patients who received antibiotics, developed diarrhoea and underwent stool enzyme immunoassay for C. difficile TOX A/B. The Kaplan-Meier and the log-rank test were used to determine univariate survival analysis and a Cox regression model for multivariate analysis of 28 day and long-term mortality. Fifty-two (24%) of the 217 patients who met the study criteria were positive for C. difficile TOX A/B. The crude 28 day and long-term mortality rates of the entire cohort were 12.4% and 56%, respectively. On Cox regression analysis, hypoalbuminaemia, impaired functional capacity and elevated serum urea levels were found to be the only independent and statistically significant variables associated with long-term mortality. C. difficile toxin positivity per se was not associated with increased short- or long-term mortality rates. In conclusion, hypoalbuminaemia, renal failure, and impaired function capacity predict mortality due to antibiotic-associated diarrhoea, but C. difficile involvement by itself does not further increase the risk of death in these patients.

Soluble triggering receptor expressed on myeloid cells-1 for distinguishing bacterial from aseptic meningitis in adults.

The aim of the present study was to evaluate whether soluble triggering receptor expressed on myeloid cells (sTREM-1) is present in the cerebrospinal fluid (CSF) of patients with acute meningitis and if its presence can predict bacterial infection. We found elevated levels of sTREM-1 in the CSF of seven of the nine (78%) patients with culture-positive specimens and in none of 12 (0%) patients with culture-negative specimens (sensitivity: 78%; specificity: 100%). The area under the receiver operating characteristic curve for sTREM-1 in the CSF as a predictor for bacterial meningitis was 0.889. This suggests that sTREM-1 is upregulated in the CSF of patients with bacterial meningitis with high specificity and that its presence can potentially assist clinicians in the diagnosis of bacterial meningitis.

The significance of Acinetobacter baumannii bacteraemia compared with Klebsiella pneumoniae bacteraemia: risk factors and outcomes.

Risk factors and outcomes for patients with nosocomial Acinetobacter baumannii bacteraemia were compared with those for patients with nosocomial Klebsiella pneumoniae bacteraemia in a single centre in Israel between 2000 and 2003. Data were collected retrospectively through patient chart review. In total, 112 patients with A. baumannii bacteraemia and 90 patients with K. pneumoniae bacteraemia were identified. A. baumannii was significantly associated with poorer performance status, mechanical ventilation, presence of devices, prior treatment with carbapenems, pneumonia as the source of infection and inappropriate empirical antibiotic treatment. All-cause 30-day mortality was higher for A. baumannii bacteraemia compared with K. pneumoniae bacteraemia (61.6% vs 38.9%, P=0.001). Variables significantly associated with mortality at the univariate level (P<0.1) were entered into a multi-variable logistic regression model for mortality. A. baumannii remained significantly associated with mortality when adjusted for all other risk factors (odds ratio 3.61, 95% confidence interval 1.55-8.39). This result did not change when the analysis was repeated for subgroups of less severely ill patients, i.e. those who were not ventilated and those who did not present with septic shock. These results support the view that nosocomial bacteraemia due to A. baumannii is associated with increased mortality.

Isolated endogenous endophthalmitis due to a sporodochial-forming Phialemonium curvatum acquired through intracavernous autoinjections.

We report a case of endogenous endophthalmitis due to a sporodochial-forming species of Phialemonium curvatum. The infection led to the enucleation of the affected eye, but there was no evidence of systemic dissemination. The isolated P. curvatum produced aggregates of phialides, many occurring on coils or in verticils, which eventually develop into sporodochia. The initial and post-enucleation isolates revealed they were identical to strains of P. curvatum from Israel causing disseminated disease in patients practicing intracavernous autoinjections for the treatment of erectile dysfunction. The reported case had unusual clinical and microbiological features. Despite the route of acquisition and the lack of systemic antifungal therapy, the infection did not spread beyond the eye. The morphology of the phialides aggregates was also unique, and the distinction between Volutella and Acremonium is discussed. This case expands the spectrum of infections due to Phialemonium species, and reveals a novel way of developing fungal endophthalmitis.

Exserohilum: an emerging human pathogen.

Exserohilum is a dematiaceous fungus that may cause a spectrum of diseases in humans, including skin and corneal infection, invasive disease, and allergic fungal sinusitis. The aim of this work is to describe two new cases of Exserohilum infection and to review the literature. The review yielded 33 cases of Exserohilum infection, of which 23 were reported since 1993. Most occurred in regions with hot climates, such as India, Israel, and the southern USA. Impaired immunity was present in the majority of patients with invasive and skin infections, whereas local trauma and atopy were the predisposing factors in those with corneal infections and allergic fungal sinusitis, respectively. Surgical debridement was the principal mode of therapy for allergic fungal sinusitis. Amphotericin B was the initial single antifungal agent used in all cases of invasive disease; the response rate was low but improved with the addition of triazole agents. Outcome appeared to be better than for other mold infections and depended mainly on the underlying diseases.

Infectious complications of implantable ports and Hickman catheters in paediatric haematology-oncology patients.

The aim of this study was to define and compare the infectious and non-infectious complications associated with Hickman catheters and implantable ports in children. The study was conducted over a three-year period in the Department of Haematology-Oncology at the Schneider Children's Medical Center of Israel. All patients who required a central venous catheter (CVC) were included in the study. For each episode of catheter-associated bloodstream infection, demographic, clinical and microbiology data were recorded. During the study period, 419 tunnelled CVCs (246 implantable ports and 173 Hickman) were inserted in 281 patients. Compared with implantable ports, Hickman catheters were associated with a significantly higher rate of bloodstream infections (4.656 vs 1.451 episodes per 1000 catheter-days), shorter time to first infection (52.31 vs 108.82 days, P < 0.001), shorter duration of catheterization (140.75 vs 277.28 days, P < 0.001), and higher rate of removal because of mechanical complications (P < 0.005). Gram-positive bacterial infections were more prevalent in the implantable port group (63.6% vs 41.6%), whereas Gram-negative rods, polymicrobial infections and mycobacterial infections were more prevalent in the Hickman group (31.4% vs 50.9%, 17% vs 36% and 0% vs 4.4%, respectively; P < 0.05 for all). Haematopoietic stem cell transplantation was identified as an independent risk factor for infection [odds ratio (OR) -1.68, P = 0.005] and for catheter removal due to complications (OR -2.0, P < 0.001). Implantable ports may be considered the preferred device for most paediatric oncology and stem cell transplantation patients.

Species distribution and antifungal susceptibility of Candida bloodstream isolates in a tertiary medical center in Israel.

To evaluate the species distribution and antifungal susceptibility of Candida isolates in a tertiary institution in Israel, all consecutive isolates of Candida spp. recovered from blood during the last 2 years were studied. The isolates were identified by the germ tube test and the API ID 32C test (bioMérieux, Marcy l'Etoile, France). MICs of antifungal agents were determined by the E test. Candida albicans was the most commonly isolated species, accounting for 44% (63/142) of the isolates, followed by Candida tropicalis (25%; 35/142), Candida parapsilosis (20%; 29/142), Candida glabrata (10%; 14/142), and Candida krusei (0.7%; 1/142). All isolates were sensitive to amphotericin B and voriconazole. Resistance to fluconazole (using a high MIC of >/=256 microg/ml) was found in 1.6% of C. albicans isolates, in 3.4% of C. parapsilosis isolates, and in 21.4% of C. glabrata isolates. Resistance to itraconazole was detected in 3.2% of C. albicans isolates, in 2.9% of C. tropicalis isolates, in 3.4% of C. parapsilosis isolates, and in 93% of C. glabrata isolates. Disparities in species distribution and antifungal susceptibility of Candida isolates from the institute studied versus Candida isolates from other centers and countries are described. The findings emphasize the need for continuous surveillance and further clinical investigational studies.

Characteristics of candidaemia with Candida-albicans compared with non-albicans Candida species and predictors of mortality.

Candidaemia due to non-albicans Candida species is increasing in frequency. We describe 272 episodes of candidaemia, define parameters associated with Candida albicans and other Candida species, and analyse predictors associated with mortality. Patients with C. albicans (55%) had the highest fatality rate and frequently received immunosuppressive therapy, while patients with Candida parapsilosis (16%) had the lowest fatality and complication rates. Candida tropicalis (16%) was associated with youth, severe neutropenia, acute leukaemia or bone marrow transplantation, Candida glabrata (10%) was associated with old age and chronic disease, and Candida krusei (2%) was associated with prior fluconazole therapy. The overall fatality rate was 36%, and predictors of death by multi-variate analysis were shock, impaired performance status, low serum albumin and congestive heart failure. Isolation of non-albicans Candida species, prior surgery and catheter removal were protective factors. When shock was excluded from analysis, antifungal therapy was shown to be protective. Unlike previous concerns, infection with Candida species other than C. albicans has not been shown to result in an increased fatality rate.

Acinetobacter baumannii: emergence and spread in Israeli hospitals 1997-2002.

The incidence of multi-drug-resistant Acinetobacter baumannii bloodstream infections (BSIs) increased two- to four-fold in three Israeli hospitals between 1997 and 2002, accounting for 3.5-18% of all hospital-acquired BSIs. This was associated with increasing carbapenem resistance reaching 35-54%, and by a dramatic increase in carbapenem consumption. In-hospital fatality rates ranged between 47% and 58% and were significantly higher than those seen with other nosocomial Gram-negative pathogens. A. baumannii was not restricted to intensive care units, but had spread to all hospital wards. Multi-drug-resistant A. baumannii has the potential to reach endemicity in hospitals and warrants more vigorous and innovative efforts to limit its spread.