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.

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.

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.

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.

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.

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.

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.

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.

Severe Chlamydia trachomatis pneumonia in a patient with no immune deficiency.

A 40-year-old patient with no immune deficiency was admitted because of severe bilateral pneumonia and pleural effusion. The diagnosis of Chlamydia trachomatis pneumonia was confirmed by isolation of the pathogen and the appearance of serum antibodies to Chlamydia species.

Bacteremia in adult diabetic patients.

OBJECTIVE: To compare the microbiology, sources, complications, and outcome of bacteremia in diabetic and nondiabetic patients. RESEARCH DESIGN AND METHODS: A prospective study was conducted of all episodes of bacteremia in hospitalized diabetic and nondiabetic patients. The study consisted of patients greater than or equal to 18 yr of age with bacteremia detected within a 19-mo interval. RESULTS: We compared 124 episodes of bacteremia in 119 diabetic patients to 508 episodes in 480 nondiabetic patients. Diabetic patients were older than nondiabetic patients (median age 74 vs. 68 yr, P = 0.0001). In patients with an indwelling urinary catheter and bacteremic urinary tract infection, the percentage of Klebsiella in diabetic patients was 60% (6 of 10) and in nondiabetic patients was 17% (4 of 23, P = 0.04). In patients without an obvious source of bacteremia, the percentage of staphylococcal isolates in diabetic patients was 29% (10 of 35) and in nondiabetic patients was 14% (24 of 176, P = 0.04). Staphylococci were a common cause of bacteremic infections of the extremities in diabetic patients (12 of 19, 63%) and nondiabetic patients (20 of 50, 40%). Septic shock was the only complication that was more common in diabetic patients. The mortality in diabetic and nondiabetic patients was 28 and 29%, respectively. CONCLUSIONS: Our results represent elderly patients with non-insulin-dependent diabetes mellitus. In this group, empirical treatment for suspected bacteremic urinary tract infection in patients with a urinary catheter should include coverage for Klebsiella. Empiric treatment for suspected bacteremia of unknown origin or caused by infection of the extremities should include an antistaphylococcal drug. The prognosis of bacteremia in diabetic and nondiabetic patients was similar.

Excess mortality in women with hospital-acquired bloodstream infection.

PURPOSE: We examined the outcomes of bloodstream infection in men and in women and whether any sex-related differences were explained by underlying disorders, severity of disease, or clinical management. SUBJECTS AND METHODS: Using a prospectively collected database, we compared in-hospital mortality in men and women. We used multivariable logistic regression analysis to test whether sex-related differences could be due to potential confounders. RESULTS: Of 4250 patients with bloodstream infections, 1750 (41%) had hospital-acquired infections. The overall case fatality was 31% (625 of 2032) in women and 29% (631 of 2218, P = 0.1) in men. However, 43% (325/758) of the women with hospital-acquired infections died, compared with 33% (327/992) of the men (P = 0.0001). In a multivariate analysis, female sex was associated with greater mortality in patients with hospital-acquired infections (odds ratio = 1.7; 95% confidence interval: 1.1 to 2.6). The excess mortality in women was mainly seen in patients with major underlying disorders (fatality rate of 45% [234 of 525] in women vs. 32% in men [234 of 743, P = 0.0001). CONCLUSIONS: Mortality in women with hospital-acquired bloodstream infections is substantially greater than in men. The excess mortality was concentrated in women with severe underlying disorders, suggesting that sepsis might have accentuated differences in the outcome of underlying disorders in women.

Uropathogens of various childhood populations and their antibiotic susceptibility.

To define the uropathogens of various childhood populations and their antibiotic susceptibility, 646 episodes of urinary tract infections (UTI) were studied. Of the community-acquired UTI 78% were caused by Escherichia coli and 12% by Klebsiella whereas only 65% of hospital-acquired UTI were caused by E. coli (P less than 0.01), and other pathogens, including Pseudomonas, were more common. In children with UTI who did not have an underlying disorder, most infections were caused by E. coli and Klebsiella species. Children with urinary malformations or urinary catheters or those who developed UTI while receiving antibiotic prophylaxis had fewer E. coli infections and more infections caused by other pathogens, including Pseudomonas (P less than 0.01). Children receiving antibiotic prophylaxis had also significantly more Enterococcus and Acinetobacter infections (P less than 0.001), and children with urinary catheters had more Enterobacter infections (P less than 0.05). Isolates of these risk groups showed increased resistance to antibiotics. Only 30-53% were susceptible to trimethoprim-sulfamethoxazole, which is usually recommended for UTI; 19 to 25% and 27 to 66% were susceptible to ampicillin and cephalothin, respectively. In contrast uropathogens of immunocompromised children did not differ significantly from those of children with no underlying disturbances, nor did they show distinct antibiotic susceptibility patterns.

Mycetoma of the renal pelvis caused by Fusarium species.

A preterm infant, with posterior urethral valves had a mycetoma of the renal pelvis caused by Fusarium species. Prolonged treatment with amphotericin B alone or with flucytosine failed. Combined surgical drainage and medical therapy resulted in full resolution.

A prospective study of Gram-negative bacteremia in children.

BACKGROUND: Hospital- and community-acquired Gram-negative bacteremia is a significant cause of mortality and morbidity in pediatric medical centers. Gram-negative organisms are isolated in > 50% of pediatric patients with bacteremia. OBJECTIVES: To analyze clinical and epidemiologic variables associated with Gram-negative bacteremia in a tertiary children's medical center. METHODS: A 6-year prospective study of children with Gram-negative bacteremia in a tertiary care children's medical center in Israel. RESULTS: Three hundred seventy-four episodes of Gram-negative bacteremia were studied during 6 years. The predominant isolates were Klebsiella pneumoniae, Pseudomonas aeruginosa and Escherichia coli, which accounted for 109, 81 and 79 episodes (26, 20 and 19%), respectively. Of all episodes 43% occurred in neonates and infants younger than 2 years and 47% were hospital-acquired. Underlying conditions mainly acute leukemia and lymphoma, were present in 55% of the patients. Urinary tract infection followed by lower respiratory tract infection were the most common identified sources of bacteremia. Central intravenous catheters were associated with 53% of the episodes. The crude mortality was 11.4%. Increased mortality was significantly associated with acute leukemia, neutropenia, hospital-acquired infections and previous corticosteroid therapy (P = 0.03, 0.003, 0.006 and 0.01, respectively). Increased antibiotic resistance of hospital-acquired vs community-acquired isolates was noted; 44 to 77% resistance of nosocomial Klebsiella and Enterobacter sp. to second and third generation cephalosporins and 18% were resistant to amikacin. CONCLUSIONS: Klebsiella pneumoniae is currently the most common organism causing Gram-negative bacteremia in children. Because of the relatively high resistance of Gram-negative organisms to second and third generation cephalosporins, we suggest that empiric antibiotic therapy for Gram-negative bacteremia include a combination of an aminoglycoside and an anti-Pseudomonas beta-lactam.

Yield of bronchoalveolar lavage in ventilated and non-ventilated children after bone marrow transplantation.

A study was undertaken to retrospectively evaluate the yield of bronchoalveolar lavage (BAL) in a single-institution series of children after bone marrow transplantation (BMT) and to compare the yield of BAL between the ventilated and nonventilated patients. We reviewed charts of 52 consecutive children after BMT who underwent BAL. Thirty patients (41 BALs) were nonventilated (group 1) and 33 patients (45 BALs) were ventilated for respiratory failure (group 2). Eleven patients were included in both groups. BAL was performed a median of 255 and 28.5 days after BMT in groups 1 and 2, respectively (P < 0.001). Group 1:17 pathogens were isolated from 13 BALs; a single pathogen from 10 BALs. Group 2:15 pathogens were isolated from 14 BALs (31.1% positive). Viruses were isolated from 13 BALs in group 2. A severe complication of BAL occurred in only one patient from group 1 (1.1%). Open lung biopsies were performed in one patient in group 1 and eight patients in group 2. The histological findings correlated with the BAL findings in 66.7%. In conclusion, there was no difference in the yield of BAL between the groups. Therapy was changed in one third of the patients dictated by the BAL findings. The risk of severe complications was relatively low. A good correlation between open lung biopsy (OLB) and BAL was found.

Prognostic significance of the neutrophil count in immunocompetent patients with bacteraemia.

To examine the prevalence of neutropaenia in immunocompetent, bacteraemic patients, and whether it carries an independent risk for mortality, we surveyed 2096 bacteraemic patients without malignant diseases, and who were not receiving cytotoxic drugs. The granulocyte count on the day of the first positive blood culture was < 1 x 10(9) cells/l in 33 patients (1.7%, group 1); 1.0-4.0 x 10(9) cells/l in 154 patients (7.9%, group 2); 4.0-8.0 x 10(9) cells/l in 564 patients (29%, group 3); 8.0-20.0 x 10(9) cells/l in 1034 patients (53%, group 4); and > 20.0 x 10(9) cells/l in 163 patients (8.4%, group 5). The mortality rates in the five groups were 39.4%, 18.8%, 18.1%, 25.7% and 25.8%, respectively (p = 0.0001). The main pathogens in group 1 were Staphylococcus aureus in 25% of patients and Pseudomonas sp. in 23%. Mortality in group 1 patients was higher than in the other patients (odds ratio 1.4, 95% CI 1.1-1.9]. Mortality was also significantly higher in group 2 patients with high blood urea nitrogen. The percentage of neutropaenia, septic patients without known risk factors for neutropaenia is small, but their mortality is high. Overall mortality in patients with relative neutropaenia (1.0-4.0 x 10(9) cells/l) is low, but a subgroup of patients with high blood urea nitrogen is at considerable risk for a fatal outcome. High leucocyte counts are also a marker of increased risk for mortality, but this association is not an independent prognostic factor.

In vitro susceptibility of recent clinical isolates of Chlamydia trachomatis to macrolides and tetracyclines.

We tested the in vitro activity of clarithromycin, azithromycin, roxithromycin, erythromycin, doxycycline, and tetracycline against 50 clinical isolates of Chlamydia trachomatis. The minimal inhibitory concentrations (MICs) and the minimal bactericidal concentrations (MBCs) were determined in a tissue culture system using cycloheximide treated McCoy cells. MIC values for all the isolates were < or =0.015 microg/ml for clarithromycin, < or =0.125 microg/ml for roxithromycin and azithromycin, and < or =0.25 microg/ml for erythromycin and doxycycline. Almost half of the isolates (44%) were inhibited only by a concentration of 0.5 microg/ml of tetracycline. MBC as high as 4 microg/ml was displayed by doxycycline and tetracycline against 8% and 4% of the isolates respectively of the agents recommended by the Center for Disease Control as drugs of choice for the treatment of chlamydial infections, azithromycin exhibited a markedly better in-vitro activity than did erythromycin and doxycycline.

Male genital mycoplasmas and Chlamydia trachomatis culture: its relationship with accessory gland function, sperm quality, and autoimmunity.

To study the effect of mycoplasmas and Chlamydia trachomatis infection on semen quality, these microorganisms were cultured from the semen and anterior urethra respectively, in a group of 175 infertile men suspected of a silent genital infection with a poor postcoital test. Chlamydia infection, but not mycoplasmas, was parodoxically more frequent in the apparently normal than oligotetratoasthenozoospermia patients. Mycoplasmas male infection, but not chlamydia, was more frequent in cases with female, mechanical, and/or organic infertility factors. Infection was unrelated to the accessory gland evaluation or sperm variables. However, seminal antisperm antibody activity was significantly increased in cases with any positive culture. By this local antibody increase, chlamydia and mycoplasmas may significantly reduce sperm egg penetration ability.