Comparison of the clinical course of Clostridium difficile infection in glutamate dehydrogenase-positive toxin-negative patients diagnosed by PCR to those with a positive toxin test

OBJECTIVES

To evaluate the potential role of PCR-based assays in the over-diagnosis of Clostridium difficile infection (CDI) by using a validated diagnostic algorithm in daily clinical practice.

METHODS

We performed a retrospective cohort study evaluating all C. difficile-positive stool samples identified at our institution during a 12-month period, to compare outcomes and recurrence rates between patients with a positive enzyme immunoassay (EIA) for both glutamate dehydrogenase (GDH) and toxin A/B ('toxin-positive group'), with those with GDH-positive, toxin-negative samples in whom the diagnosis was made by a positive PCR-based assay ('toxin^-/PCR⁺ group'). Medical records were reviewed by two independent investigators blinded to the mode of diagnosis.

RESULTS

We analysed 231 first CDI episodes (106 (45.8 %) in the 'toxin-positive group' and 125 (54.1%) in the 'toxin^-/PCR⁺ group'). Both groups had similar baseline characteristics. Patients in the 'toxin-positive group' presented more frequently with a severe/severe complicated form than those in the 'toxin^-/PCR⁺ group' (36 (33.9%) versus 24 (19.2%); p 0.011) and had more recurrences (27 (25.5%) versus 9 (7.2%); p 0.001). Diagnosis of CDI based on a GDH/toxin-positive EIA independently predicted severe/severe-complicated course (adjusted OR 2.11; 95% CI 1.06-4.22; p 0.033) and recurrence (adjusted OR 3.79; 95% CI 1.65-8.69; p 0.002). There were no differences in all-cause mortality (12.3% versus 12.0%; p 0.95) or CDI-attributable mortality (4.7% versus 4.8%; p 0.93).

CONCLUSIONS

Toxin-positive patients were more likely to have severe-complicated forms of CDI and recurrences. Nevertheless, CDI-related complications may still occasionally occur among toxin-negative patients diagnosed by PCR, which stresses the need for individualized clinical evaluation.

Influence of antiviral therapy in the long-term outcome of recurrent hepatitis C virus infection following liver transplantation

INTRODUCTION

Severity of recurrent hepatitis C virus (HCV) infection in liver transplant recipients (LTR) is variable and the influence of different factors, including the administration of antiviral therapy in the long-term outcome is controversial.

METHODS

We analyzed the outcome of a cohort of HCV-infected LTR who were transplanted in our institution. Patients were divided into 2 groups (severe and non-severe HCV disease) depending on the presence of a fibrosis score of F ≥ 2 in the Scheuer index and/or fibrosing cholestasic hepatitis (FCH) in a graft biopsy. Risk factors were studied using logistic regression analysis. Survival of patients was estimated using Kaplan-Meier plots. A total of 146 patients were followed for a mean of 58 months.

RESULTS

Fifty-six (34%) patients developed severe HCV disease and showed shorter survival (P < 0.024). Donor age (odds ratio [OR]: 1.04; 95% confidence interval [CI]: 1.02-1.06) and pre-transplant viral load (VL) >10(6) UI/mL (OR: 3.5; 95% CI: 1.42-10.61) were the only factors associated with severe HCV infection. Over-immunosuppression (OR: 2.3; 95% CI: 1.2-4.41) was specifically associated with the development of FCH. Overall, patient survival in recipients who received a full course of anti-HCV therapy was higher than in patients who did not complete antiviral therapy (P = 0.004) or received no treatment (P = 0.007). Patients with non-severe HCV infection have a higher probability of receiving a full course of antiviral therapy (P = 0.033).

CONCLUSION

In conclusion, donor age, pre-transplant VL, and over-immunosuppression were associated with the long-term development of severe HCV recurrence in liver grafts. Administration of a full course of antiviral therapy was associated with better survival.

Epidemiology, risk factors and impact on long-term pancreatic function of infection following pancreas-kidney transplantation

Limited information exists about epidemiology and risk factors of infection following pancreas-kidney transplantation and its impact on long-term pancreatic graft function. A retrospective chart review of episodes of severe infection in consecutive pancreas-kidney transplantations in a single institution was performed to assess the epidemiology, risk factors for infection and their impact on the development of pancreatic graft dysfunction. Ninety-four (81%) of 116 recipients (median follow-up of 1492 days; mean 1594) developed 248 episodes of severe infection. Bacterial infections were present in 208 episodes, with 12% of the isolates resistant to antibiotics used in prophylaxis. There were 40 episodes of fungal infection in 32 patients (28%) (mostly Candida spp), and CMV disease appeared in 20 patients (17%), of which 50% appeared after the third month following surgery. The multivariate analysis identified that surgical re-intervention and the use of steroid pulses were independently associated with the development of any infection. Additionally, pre-transplant evidence of peripheral artery disease, a longer cold ischaemia time and high transfusional requirements were associated with fungal infections. Cytomegalovirus (CMV) mismatch was independently related to CMV disease and female sex, and bladder drainage of the exocrine pancreas was associated with urinary tract infection. At the end of follow-up, 29 patients (25%) had developed severe pancreatic graft dysfunction, and fungal infection was independently associated with it. Our study identifies a subset of pancreas-kidney transplant recipients at a higher risk of developing severe infection. Fungal infection is an independent risk factor for the development of severe pancreatic graft dysfunction.

Primary hepatic actinomycosis presenting as purulent pericarditis with cardiac tamponade

Cardiac tamponade constitutes an exceptional form of actinomycosis. We describe a case of primary hepatic actinomycosis presenting as purulent pericarditis with cardiac tamponade in a 20-year-old patient with previous esophagectomy and colonic interposition, successfully managed by computed tomography-guided percutaneous drainage and a prolonged course of antibiotic treatment. Actinomyces israelii was identified in the pericardial fluid by 16S rRNA gene sequencing. The literature on the simultaneous presentation of cardiac and hepatic actinomycosis is reviewed.

A new strategy of delayed long-term prophylaxis could prevent cytomegalovirus disease in (D+/R-) solid organ transplant recipients

Long-term prophylaxis against cytomegalovirus (CMV) started immediately after transplantation in (D+/R-) poses a higher risk of late-onset CMV disease. Delayed CMV prophylaxis could allow a transitory exposure of the immune system to CMV, which would let the immune system mount an adequate CMV-specific cytotoxic response in (D+/R-) patients and confer protection against CMV disease. We included all (D+/R-) solid organ transplant recipients (SOT) performed at our institution (January 3/October 6) who received CMV prophylaxis (mainly with oral valganciclovir) during 100 d. In the first period (until December 4), prophylaxis was initiated immediately after transplantation (conventional prophylaxis: CP). Since January 5, it was initiated after 14 d (delayed prophylaxis: DP). Incidence and severity of CMV disease was compared between both groups. A total of 44 SOT recipients were included (CP: 26 and DP: 18). CMV disease was diagnosed in eight patients (18%), seven of 26 (27%) in the CP group, and one of 18 (5.5%) in the DP group (p = 0.07). CMV colitis was reported in five of 26 patients in the CP group (19%), whereas there were no cases of visceral CMV disease in the DP group (p = 0.048). A 14-d delay in the beginning of long-term prophylaxis against CMV in (D+/R-) is safe and could prevent the onset of late-CMV disease.

Incidence, clinical characteristics and risk factors of late infection in solid organ transplant recipients: data from the RESITRA study group

Information describing the incidence and clinical characteristics of late infection (LI) in solid organ transplantation (SOT) is scarce. The aim of this study was to define the incidence, clinical characteristics and risk factors for LI (>6 months) as compared with infection in the early period (<6 months) after SOT. By the online database of the Spanish Network of Infection in Transplantation (RESITRA) we prospectively analyzed 2702 SOT recipients from September 2003 to February 2005. Univariate and multivariate analysis using logistic regression were performed to calculate the risk factors associated with the development of LI. A total of 131 patients developed 176 LI episodes (8%). Global incidence of LI was 0.4 per 1000 transplant-days, ranging from 0.3/1000 in kidney transplants to 1.4 in lung transplants. Independent risk factors for LI in were: acute rejection in the early period (OR 1.5; CI 95%: 1.1-2.3), chronic graft malfunction (OR 2; CI 95%: 1.4-3), re-operation (OR 1.9; CI 95%: 1.3-2.8) relapsing viral infection apart from CMV (OR 1.9; CI 95%: 1.1-3.5), previous bacterial infection (OR 1.8; CI 95%: 1.2-2.6) and lung transplantation (OR 4.5; CI 95%: 2.6-7.8). Severe LI occurs in a subgroup of high-risk SOT recipients who deserve a more careful follow-up and could benefit from prolonged prophylactic measures similar to that performed in the early period after transplantation.

[Individualized evaluation of the risk of infections in the oncohematologic patient]

In order to take the best approach to infection in the oncohematologic patient with fever, it is important to know not only how profound the neutropenia is and how long the patient has had it, but also the characteristics of the underlying disease, the immunosuppressive therapy received and the type of hematopoietic stem/progenitor cell transplantation performed. Moreover, is important to consider if these patients have any personal or familial history of infectious diseases. All these aspects let us calculate the net state of immunosuppression and the risk of infection, and provide us with information about the most probable etiology in each case and the best prophylaxis and treatment. In this study we review the more important advances in chemotherapy in recent years that will make it necessary in the future to change our prophylactic guidelines for more effective prevention of infection in the oncohematologic patient.

Accuracy of blood culture for early diagnosis of mediastinitis in febrile patients after cardiac surgery

Postsurgical mediastinitis (PSM) remains a major cause of morbidity and mortality in patients undergoing cardiac surgery procedures. Although prompt diagnosis is crucial in these patients, neither clinical data nor imaging techniques have shown enough sensitivity or specificity for early diagnosis of PSM. The aim of the present study was to assess the validity of blood cultures as a diagnostic test for the early detection of PSM in patients who become febrile after cardiac surgery procedures. During a 4-year period (1999-2002), patients who developed fever (>37.8 degrees C) in the first 60 days after a cardiac surgery procedure were evaluated. Blood cultures were drawn from these patients. PSM was defined as deep infection involving retrosternal tissue and/or the sternal bone directly observed by the surgeon and confirmed microbiologically. Three criteria for positivity of blood cultures were applied: bacteremia, staphylococcal bacteremia, or Staphylococcus aureus bacteremia. For purposes of the analysis, a positive blood culture in patients with PSM was considered a true-positive test and a negative blood culture a false-negative test. Otherwise, in febrile patients without PSM in the postsurgery period, a positive blood culture was considered a false-positive test and a negative blood culture a true-negative test. Blood cultures were drawn from 266 febrile patients in the postsurgery period. PSM occurred in 38 patients (26 cases due to S. aureus, 8 to Staphylococcus epidermidis, 3 to gram-negative enteric bacteria, and one to Pseudomonas aeruginosa). Within the 60-day postsurgical period, blood culture as a diagnostic test was most accurate in patients with S. aureus bacteremia, providing 68% sensitivity, 98% specificity, a positive predictive value of 87%, and a negative predictive value of 95%. If the analysis was limited to the period during which patients are at maximum risk for PSM (day 7-20), the values in patients with S. aureus bacteremia were as follows: 73% sensitivity, 98% specificity, 90% positive predictive value, and 93% negative predictive value. Blood culture is an accurate test for the early diagnosis of PSM in febrile patients after cardiac surgery, particularly in institutions where S. aureus is prevalent in this context. A negative blood culture practically excludes PSM and, during the period of maximum risk for PSM, the presence of S. aureus bacteremia should compel early surgical management.

Clinical significance of donor-unrecognized bacteremia in the outcome of solid-organ transplant recipients

We evaluated the clinical significance of unrecognized bacteremia in the organ donor (i.e., blood culture results that were reported to be positive after transplantation) on the outcome of transplant recipients. Twenty-nine of 569 liver and heart donors (5%) had bacteremia at the time of organ procurement, but there were no documented instances of transmission of the isolated bacteria from the donor to the recipient. Unrecognized bacteremia in the donor does not have a negative clinical impact on the outcome of organ transplant recipients.

[Invasive fungal infections in liver transplant recipients: analysis of 21 cases]

BACKGROUND

Invasive fungal infections (IFI) are one of the most important causes of mortality in liver transplant (LT) recipients. The aim of this study was to describe the characteristics of IFI in the LT program of our institution with an special emphasis in the differences between Candida infections (CI) and that caused by other fungi (NCI).

PATIENTS AND METHODS

Retrospective analysis of the hospital charts of 21 patients who underwent a LT from February 1987 to December 1995. The diagnosis of IFI required the histological evidence of tissue invasion or a positive culture in a tissue sample or in an usually sterile fluid. Esophageal candidiasis was not considered as IFI. Antifungal prophylaxis was performed either with nystatin or fluconazole.

RESULTS

Twenty-one of 356 patients (6%) developed a total of 23 episodes of IFI. Pathogens were Candida spp. (n = 10), Aspergillus (n = 8), Zygomicetes (n = 4) and Cryptococcus (n = 1). Fifty-seven percent of the episodes of IFI (80% of those caused by Candida and 38% of those produced by other fungi; p < 0.05) developed in the first 3 months after transplantation and only 5 episodes appeared after the sixth month. The diagnosis of IFI was done at autopsy in 6 patients (29%). Overall, NCI (13 episodes) predominated over CI (10 episodes), being the later the cause of the 54% of the episodes in the first 178 recipients but only the 30% in the last 178 patients (p = 0.09). No differences were found in the distribution of the risk factors amongst those patients with CI or NCI. Seventeen of the 21 patients (71%) died and 15 of these deaths (72%) were attributable to fungi; 15 patients who died either did not receive amphotericin (n = 6) or received a cumulative dose lower than 500 mg. Six patients received a cumulative dose of more than 1.5 g (mean, 3.2 g) and four of them were cured. Mortality in the nonfungal infection group was 26% (p < 0.001).

CONCLUSIONS

IFI was a rare but severe complication in our LT recipients. The relative frequency of CI was progressively decreasing during the study period, being NCI the predominant infections. Amphotericin therapy was effective only when a high cumulative dose could be administered.

Clinical, virological, and histologic evolution of hepatitis C virus infection in liver transplant recipients

We designed a prospective study to assess the time course and evolution of hepatitis C virus (HCV) infection in 152 patients who underwent a liver transplantation (LT) in our institution. Forty-four recipients (29%) were infected by HCV after transplantation: 40 who developed recurrent infection after LT and four who acquired infection during or after LT. No differences were found in survival actuarial rates at 1, 2, and 4 years after transplantation for patients infected by HCV vs. noninfected ones. Graft hepatitis occurred in 66% of HCV-infected recipients: 18 developed chronic active hepatitis (10 of them with intense fibrosis) and 2 developed cirrhosis during the follow-up. Infection by the HCV-1b genotype was found in 79% of the infected recipients and in 100% of those in whom histologic evolution was worst. Fourteen grafts were lost in 44 HCV-infected recipients, in comparison with 12 in 108 HCV-negative patients (P = .007), mostly because of chronic rejection. HCV infection did not affect life expectancy in the midterm follow-up for LT patients. However, it was often associated with the occurrence of early and severe graft hepatitis and with a higher incidence of graft loss due to chronic rejection.

Prospective randomized trial of efficacy of ganciclovir versus that of anti-cytomegalovirus (CMV) immunoglobulin to prevent CMV disease in CMV-seropositive heart transplant recipients treated with OKT3

We compared the efficacy of ganciclovir versus that of cytomegalovirus (CMV) immunoglobulin for the prevention of CMV disease in 31 CMV-seropositive heart transplant recipients who had received early immunoprophylaxis with OKT3 monoclonal antibodies. The incidence of CMV disease and visceral involvement was much higher in the CMV immunoglobulin group than in the ganciclovir group (40 versus 6%, respectively; P = 0.03). No adverse effects were found in the CMV immunoglobulin group, but 19% of the patients in the ganciclovir group developed mild leukopenia or a mild increase in their serum creatinine levels.

Clinical significance of hepatitis C virus (HCV) infection in liver transplant recipients. Role of serology and HCV RNA detection

Hepatitis C virus (HCV) infection was studied in 60 liver transplant recipients. Antibodies to HCV were tested by both a second-generation ELISA test and a four-recombinant immunoblot assay (4-RIBA) just before the transplant and every three months thereafter. HCV RNA detection was performed by polymerase chain reaction (PCR) at least three times after the transplant in all the patients. Thirty-nine patients tested negative by ELISA before LT (group A), 14 patients tested positive by both serological tests (group B), and seven tested positive only by ELISA (group C). Posttransplant hepatitis was diagnosed in 11/14 in group B in comparison with 3/39 in group A (P < 0.001) and 1/7 in group C (P < 0.05). HCV RNA was detected in the sera of 14/14 patients in group B but in only 1/7 in group C and 6/39 in group A. Only 2/15 patients developed posttransplant hepatitis in the absence of HCV RNA detection. These data suggest that HCV is the major cause of hepatitis after LT. Patients HCV seropositive by RIBA test before the transplant formed a group of high-risk patients for developing viremia and hepatitis afterwards.

Ganciclovir prophylaxis decreases frequency and severity of cytomegalovirus disease in seropositive liver transplant recipients treated with OKT3 monoclonal antibodies

The efficacy of ganciclovir, given prophylactically, to prevent cytomegalovirus-related disease was evaluated in liver transplant recipients, mostly seropositive, under treatment with OKT3 monoclonal antibodies. The incidence of cytomegalovirus disease and visceral involvement was reduced, respectively, from 52 and 36% in the control group to 12 and 8% in the ganciclovir-treated patients. Leukopenia was a frequent (32%) side effect of ganciclovir administration.

Meningoencephalitis and polyradiculoneuritis in adults: don't forget rubella

We describe a severe case of meningoencephalitis and polyradiculoneuritis that occurred following rubella in an otherwise healthy 19-year-old man. The diagnosis was made serologically. To our knowledge this is the first reported case of extensive neurological involvement in an adult with rubella.

Encrusted pyelitis and cystitis by Corynebacterium urealyticum (CDC group D2): a new and threatening complication following renal transplant

We evaluated the pathogenic role of Corynebacterium urealyticum in the development of encrusted pyelitis (EP) and encrusted cystitis (EC), and their clinical consequences in renal transplant recipients. During a 4-year period, we studied seven renal transplant recipients with EP and two with EC. The records of 320 other renal transplant patients studied during the same period were used as a control group. C urealyticum (> or = 10(5) CFU/ml) was isolated from 4 patients with EP (urine 3, blood 1) and from 1 patient with EC (urine). Alkaline urines with struvite crystals, microscopic hematuria, and sterile conventional urine cultures were present in all our cases. All the patients with EP developed obstructive uropathy with deterioration of the renal function and pyelonephritis (4 patients) or renal abscesses (3 patients). Chronic urinary discomfort and macroscopic hematuria were present in the 2 patients with EC. Long-term vesical and ureteral catheterization were considered the most important risk factors for the development of EC and EP, respectively. Vancomycin was successfully used in 5 cases, but all the patients required a derivative procedure or a surgical resection of the incrustations to improve. We conclude that EP and EC should be investigated in renal transplant patients who develop pyelonephritis, obstructive uropathy, or chronic urinary symptoms. EP and EC could lead to the loss of their grafts. C urealyticum appears to have a pathogenic role in these entities.

[Nosocomial fungemia caused by Candida parapsilosis]

We review 27 episodes of nosocomial fungemia due to Candida parapsilosis over a 6 year period, compared to a control group of 27 episodes of nosocomial fungemia due to Candida albicans. During the study period, C. parapsilosis accounts for 23% of all yeast isolated from blood-cultures. Fungemia due to C. parapsilosis was more frequently seen in males (23/4). More than half of the cases (15/27) presented in the postoperative period. In 89% of cases the patients were under total parenteral nutrition and 81% had received broad-spectrum antibiotics. In 41% of cases, the source of the fungemia was unknown, and in another 41% of cases was related to an iv line infection. Direct attributable mortality to C. parapsilosis infection was 11%. When compared to the control group, nosocomial fungemia due to C. parapsilosis occurs in patient with more prolonged courses of total parenteral nutrition, and also was related with less frequent development of septic shock and lower attributable mortality.

Major bacterial infections following liver transplantation: a prospective study

The incidence and characteristics of major bacterial infections were studied prospectively in 50 consecutive adult patients who underwent liver transplantation (LT). All patients received the same protocol of immunosuppression, bowel decontamination, antibiotics prophylaxis, and follow-up. Thirty-two patients (64%) had at least one episode of major bacterial infection. One death was directly related to a bacterial infection, accounting for 13% of postoperative mortality. The most critical period for infection was the first 2 months after surgery, when 69% of the infections occurred. The most frequent clinical presentations were bacteremia, pneumonia and abdominal abscesses. Eighty percent of the bacteremias had an identifiable source, the most frequent being intravascular catheters. Gram-positive microorganisms (69%) predominated over gram-negative rods (26%) and anaerobes (5%). The use of selective bowel decontamination (SBD) with norfloxacin may explain this predominance. Major bacterial infections are an important source of morbidity and mortality after LT. Efforts to prevent these infections and to determine their source and specific treatment, will improve the management and the outcome of these patients in the future.