Strongyloides stercoralis hyperinfection syndrome after liver transplantation: case report and literature review

Strongyloides stercoralis is an intestinal nematode that causes human infections and whose life cycle has special features, including autoinfection. Strongyloides infection may be asymptomatic for years, owing to a low parasite load. During immunosuppressive therapy, however, if cellular immunity is depressed, autoinfection can occur at a higher rate, resulting in hyperinfection syndrome. In this specific circumstance, it can become a fatal illness. We describe a case of hyperinfection syndrome in a liver transplant recipient and also review the literature.

Steady-state analysis of a continuum model for super-infection

A large system of N strains of parasite and a single host is analyzed as a function of the degree of virulence in the strains when there is super-infection between hosts (more virulent strains can infect hosts that are already infected) and within-host transition between strains that is neutral. When this small amount of local switching is allowed, steady-state solutions converge to a continuous distribution as the number of strains increases. The resulting nonlinear-nonautonomous integro-differential equation is reduced to a fourth order boundary value problem (BVP) and the existence of positive solutions is proven. The methods here and associated BVP allow for a thorough exploration of parameter space for this class of models.

Methicillin-resistant superinfection of the wound after body-contouring abdominal surgery

BACKGROUND

This report presents the case of a patient who underwent abdominal body-contouring surgery, then later experienced a severe deep infection and a methicillin-resistant (MRSA) superinfection.

CASE REPORT

A 56-year-old female ex-smoker presented, after massive weight loss, with skin excesses on the abdomen and flanks. She underwent an abdominoplasty with muscle plication and flank liposuction. On postoperative day 14, the woman presented with a deep wound infection, then 1 week later with MRSA superinfection. Since then, two surgical debridements and specific intravenous antibiotics have been necessary for a cure and to avoid septicemic complications. Complete wound closure was achieved only after 3 months of therapy, but a massive retractile and painful scar remained.

CONCLUSION

Concomitant risk factors for wound infections (obesity, smoking, flap undermining) determined a rare but potentially fatal wound complication after body-contouring abdominoplasty. This complication was presented to alert plastic and general surgeons to such postoperative infections and to the possibility of a nonconservative approach.

Strongyloides hyperinfection syndrome: an emerging global infectious disease

The hyperinfection syndrome (HS) caused by Strongyloides stercoralis has a high mortality rate (15% to 87%). A variety of risk factors and predisposing conditions have been described, including new immunosuppressive therapies; HTLV-1 infection; cadaveric transplantation; immune reconstitution syndrome; haematological malignancies (especially lymphoma); tuberculosis; malnutrition secondary to chronic Strongyloides diarrhoea; international travel and immigration. Inhibition of Th2 cell-mediated, humoral or mucosal immunity is associated with HS. HS is more frequently seen in HTLV-1 than HIV patients. In AIDS, there is an increase in Th2 cytokines, while in HTLV-1 infection there is a decrease in the Th2 response, leading to an increased risk of autoinfection. Corticosteroid use remains the most frequent risk factor for HS. A number of ELISAs are useful for diagnosis and post-treatment evaluation. Once diagnosed, the disease may be managed effectively with anthelminthic drugs, including ivermectin. HS causes diverse symptoms and signs, with unusual manifestations leading to misdiagnosis and medical errors related to healthcare providers' lack of familiarity with the condition. HS is an example of an emerging tropical infection migrating to developed countries and requiring greater clinician awareness.

Risk factors for yeast superinfection in the treatment of suspected exit site infections: a case-control study

PURPOSE

The risk of infection can be reduced in hemodialysis (HD) patients with central venous catheters (CVCs) by using prophylactic intranasal mupirocin or polysporin at the exit site. However, there are concerns about the potential emergence of resistant microorganisms. The purpose of our study was to determine if the use of polysporin double in the treatment of exit site infections was associated with the emergence of yeast positive exit site cultures.

METHODS

In this case control study, we evaluated the risk of developing yeast positive exit site cultures after introducing a polysporin medical directive for the treatment of presumed exit site infections in our HD units. All HD patients using a CVC for blood access at the Ottawa Hospital were eligible for study. Demographic variables, use of polysporin, antibiotics and immunosuppressive medications were compared between those patients with yeast positive exit site cultures and controls.

RESULTS

There was no differences in age, gender or diabetic status between the cases and controls. However, the use of polysporin, antibiotics and immunocompromised status were associated with an increased risk of yeast positive exit site cultures. The relative importance of each of these factors could not be determined using this study design and requires future prospective study.

CONCLUSIONS

The emergence of yeast positive exit site cultures after the introduction of a new medical directive at a tertiary care hospital highlights the difference between medications used for prophylaxis and those used for treatment of CVC infections in high risk dialysis patients.

Fungal peritonitis in patients on peritoneal dialysis: twenty five years of experience in a teaching hospital in Argentina

Fungal peritonitis is a rare but serious complication of peritoneal dialysis. The aim of this study was to analyze peritonitis rates, associated factors, clinical course, microbiological aspects, therapeutic regimens, and outcome of patients with fungal peritonitis in the dialysis center of a teaching hospital over the last 25 years. A hundred and eighty three episodes of peritonitis were detected and microbiologically documented in 57 patients. Fungi were identified in eight episodes (4.37%) occurring in seven female patients. The fungal peritonitis rate was 0.06 episodes/patient-year. Gram and Giemsa stains were positive in five out of eight dialysate fluids. The causative microorganisms were: Candida albicans in five episodes, and Candida parapsilosis, Candida glabrata, and Neosartorya hiratsukae in the remaining three. Antibiotics were administered to all but one patient, within 3 months before fungal peritonitis was detected. All patients required hospitalization, and antifungal therapy was administered in all episodes. The Tenckhoff catheter was removed in seven out of eight fungal peritonitis. All patients recovered from the fungal episodes. In the group of patients studied, it is concluded that recent exposure to antibiotics and female sex, were strongly associated with the development of fungal peritonitis by yeasts. The peritonitis caused by the environmental filamentous fungus did not require antibiotic pressure. Direct microscopy of the dialysate pellet was extremely useful for the prompt management of the fungal episode. Fungal peritonitis preceded by multiple episodes of bacterial peritonitis always determined the definitive dropout of the patient from the peritoneal dialysis program. Patients with de novo yeast-related peritonitis could continue on the program.

[Assessment of patients with poor resolution of HAP]

Emphasis in VAP management is now shifting to the effectiveness of antibiotic therapy and its effect on subsequent mortality. As many as 62% of patients with VAP meet a set of objective criteria for failure to respond. The predominant microorganisms associated with failure of therapy are Pseudomonas aeruginosa and methicillin-resistant S. aureus (MRSA). Multiple causes of failure to respond in VAP exist: compromised host immunity, occult antibiotic resistance, inadequate antibiotic dosing, and concomitant or subsequent superinfections. The diagnosis of antibiotic failure and distinguishing failure from superinfection or noninfectious mimics is difficult because clinical criteria alone are inadequate. Microbiologic response is accurate only if quantitative cultures are used. Biochemical markers may be more accurate than clinical but still don't discriminate between causes. The appropriate diagnostic strategy and treatment algorithms have not been fully addressed and more research is clearly needed.

The association of third-generation cephalosporin use and invasive candidiasis in extremely low birth-weight infants

OBJECTIVES

Previous studies have shown that incidence of invasive candidiasis varies substantially among centers, and previous use of broad-spectrum antibiotics is a risk factor for candidiasis in extremely low birth-weight infants. Differences in center practices, such as antibiotic strategies and the effects of these strategies on center incidence of candidiasis, are not reflected in assessments of an individual's risk of candidiasis. We evaluated the relationship between empirical antibiotic practices for extremely low birth-weight infants and center incidence of candidiasis.

METHODS

We studied a cohort of extremely low birth-weight infants who survived > or = 72 hours and were admitted to 1 of 12 tertiary centers between 1998 and 2001. Multivariable logistic regression was used to validate previous broad-spectrum antibiotics use as a risk factor for subsequent candidiasis in individual infants. We calculated correlation coefficients to assess the relationship between center incidence of candidiasis with antibiotic practice patterns.

RESULTS

There were 3702 infants from 12 centers included, and 284 (7.7%) developed invasive candidiasis. Broad-spectrum antibiotics use was associated with candidiasis for individual infants. Center candidiasis incidence ranged from 2.4% to 20.4%. Center incidence of candidiasis was correlated with average broad-spectrum antibiotics use per infant and average use of broad-spectrum antibiotics with negative cultures per infant.

CONCLUSIONS

Center incidences of invasive candidiasis differ substantially, and antibiotic practice differences are possible contributors to center variation in candidiasis risk.

[Adverse effects of intralesional Glucantime in the treatment of cutaneous leishmaniosis]

OBJECTIVE

The treatment of cutaneous leishmaniasis used in Tunisia is Glucantime. The aim of this retrospective study was to determine the adverse effects of intralesional Glucantime and to calculate the risk/benefit rate of this treatment.

RESULTS

Adverse effects were observed in 14 cases (5%). For facial lesions, we observed facial staphylococci in 2 cases, stibio-intolerance in 1 case, and a palpebral subcutaneous nodule in 1 case. In limb lesions the complications were: sporotrichoid nodules in 5 cases, vagal malaise (1 case), pyodermitis (1 case), erysipelas (1 case), necrosis (1 case), and urticaria (1 case).

COMMENTARY

The adverse effects of intralesional Glucantime are mostly infections, mainly observed in cephalic localization, and stibio-intolerance. For this reason, intralesional injection of Glucantime must be avoided in the cephalic region.

Candidosis in children with onco-hematological diseases in Chennai, south India

Candida spp. are recognized as a leading contributor to mortality and morbidity in patients with onco-hematological malignancies. The rates and risk factors for mycotic infections in pediatric oncology patients are undetermined, particularly for those treated at centers in developing countries. The objective of the present study was to prospectively evaluate the species stratification and antifungal susceptibility profile of Candida spp. associated with superficial and systemic infection in children with onco-hematological diseases. Acute lymphoblastic leukemia was the most common underlying disease (71.4%) among the 91 children under study. Candida albicans was the predominant species, with 17/29 isolates (58.6%); followed by C. tropicalis, with 10/29 isolates (34.5%). The drug susceptibility data analysis for the clinical isolates of Candida revealed 17.2% (5/29) resistance to fluconazole. This study reinforces the need for the systematic surveillance of candidosis for the correct management of such life-threatening infections.

[Impact of a non-compulsory antibiotic control program (PACTA): cost reductions and decreases in some nosocomial infections]

BACKGROUND

Antibiotics account for 30% of hospital pharmacy expenses. More than 50% of the prescriptions are considered inappropriate; hence, programs devoted to optimizing the prescription of antibiotics should be developed. We present the results of a non-compulsory program for the assessment and control of antibiotic treatment in the University Hospital 12 de Octubre in Madrid.

METHODS

The program was applied in the hospitalization units of six medical and surgical departments. Treatments in all patients were checked daily and recommendations were made in writing, according to previously established criteria. The program was used for 12 months and the results were compared with those of the previous 12 months.

RESULTS

1,280 treatments were reviewed and 524 recommendations were made (80% of them were accepted). There was a 13.82% reduction in the number of defined daily doses of antibiotics/100 inpatient-days. Antibiotic expenditure decreased by 65,352 euros (5,446 euros/month), implying a reduction of 1.21 euros/hospitalization-bed/day. There were no statistically significant differences in length of hospital stay or mortality between the two periods. A reduction in the incidence of Clostridium difficile diarrhea (p < 0.0001) and Candida spp. isolations (p < 0.05) was observed.

CONCLUSIONS

Following application of a non-compulsory control program, antibiotic prescription improved and expenditure decreased, with no change in length of hospital stay or mortality. There was a reduction in the incidence of some nosocomial infections. Acceptation of the program by the physicians of the departments implicated was favorable.

Tutorial: Using Confidence Curves in Medical Research

Confidence intervals represent a routinely used standard method to document the uncertainty of estimated effects. In most cases, for the calculation of confidence intervals the conventional fixed 95% confidence level is used. Confidence curves represent a graphical illustration of confidence intervals for confidence levels varying between 0 and 100%. Although such graphs have been repeatedly proposed under different names during the last 40 years, confidence curves are rarely used in medical research. In this paper, we introduce confidence curves and present a short historical review. We draw attention to the different interpretation of one- and two-sided statistical inference. It is shown that these two options also have influence on the plotting of appropriate confidence curves. We illustrate the use of one- and two-sided confidence curves and explain their correct interpretation. In medical research more emphasis on the choice between the one- and two-sided approaches should be given. One- and two-sided confidence curves are useful complements to the conventional methods of presenting study results.

Vaccination with formalin-inactivated influenza vaccine protects mice against lethal influenza Streptococcus pyogenes superinfection

Intranasal infection with non-lethal influenza A virus (IAV) followed by infection with group A streptococci (GAS) induces invasive, lethal GAS infections, including necrotizing fasciitis, in mice. We demonstrate that subcutaneous immunization of formalin-inactivated IAV vaccine or intranasal immunization of IAV vaccine and cholera toxin protected more than 75% of mice from death by lethal IAV-GAS superinfection. The increased survival rate correlates with increase in IAV neutralizing activity and the levels of serum anti-IAV IgG. Moreover, elimination of IAV from the lungs of vaccinated mice led to depletion of GAS associated with alveolar epithelial cells. These findings suggest that formalin-inactivated IAV vaccine may be useful for prevention of secondary bacterial infections following prior IAV exposure.

[Heavy diarrhea by low malignant B cell lymphoma]

A 52-year old female presented with a low, malignant centroblastic-centrocytic lymphoma. After splenectomy and under steroid therapy it came to the eruption of a latent Strongyloides stercoralis infection, which the patient had presumably been suffering from for several years. Due to the immunodeficient condition and under continued steroid therapy even three courses of high dose anthelmintic therapy could not eradicate the parasites. The patient died of fulminant sepsis.

Hypothesis of interference to superinfection between bovine spastic paresis and bovine spongiform encephalopathy; suggestions for experimentation, theoretical and practical interest

Sub-acute transmissible spongiform encephalopathies (TSEs) or prion diseases are diseases of little known etiology. The origin of these diseases would appear to be an abnormal protease-resistant prion protein (PrP(res)) which would be infectious by directly inducing its defective conformation to the normal native protein (PrP(C)). This hypothesis does not account for certain aspects of TSEs, such as interference to superinfection: in laboratory animals, inoculation by means of an attenuated strain with a long incubation period protects against later infection by a very virulent strain with a short incubation period. The hypothesis is put forward that there exists a possibility of interference to superinfection between neurodegenerative diseases of unknown origin, thought to be similar to TSEs, and a later infection by a TSE. The study of this interference between bovine spastic paresis (BSP) and bovine spongiform encephalopathy (BSE) could be used as a model for this hypothesis. BSP is a very rare disease among cattle, of unknown etiology; it is curable, in the very early stages, by using tryptophan and especially lithium, potentiated by copper and manganese. An etiology close to that of TSEs has been suggested on several occasions. If interference could be demonstrated between BSP and BSE, interesting data would be provided concerning the etiology, the pathogenesis and possibly the treatment and prevention of these diseases. Notably, such data could lead to the development of a treatment and a prevention with lithium and amino acids precursors of neuromediators (tryptophan, tyrosine, glutamic acid, etc.), as well as the developing of a vaccine to combat TSEs, especially BSE and scrapie.

[Role of some representatives of opportunistic microflora in development of secondary infection in patients with pulmonary tuberculosis]

The results of the laboratory diagnosis of secondary (mixed) infection of the respiratory tracts in patients with respiratory tract tuberculosis were summarized. The study was performed for 12 months in a Tuberculosis Clinic. The species of the pathogens and the frequency of their detection in various clinical specimens from pulmonary tuberculosis patients were determined. The data on resistance of the strains of Streptococcus viridans group isolated from the pulmonary tuberculosis patients to various antimicrobials including new fluoroquinolones are presented.