Evelina Tacconelli

Systematic reviews: CRD's guidance for undertaking reviews in health care

Riedel DJ, Gonzalez-Cuyar LF, Zhao XF, Redfi eld RR, Gilliam BL. Plasmablastic lymphoma of the oral cavity: a rapidly progressive lymphoma associated with HIV infection. Lancet Infect Dis 2008; 8: 261–67. In this Grand Round, the references for the sentence “Occasionally, CD138-negative plasmablastic lymphoma cases (such as this case) have been reported” (page 265) should be 32, 34, and 38. Book Systematic reviews: CRD’s guidance for undertaking reviews in health care

The global threat of antimicrobial resistance: science for intervention

In the last decade we have witnessed a dramatic increase in the proportion and absolute number of bacterial pathogens resistant to multiple antibacterial agents. Multidrug-resistant bacteria are currently considered as an emergent global disease and a major public health problem. The B-Debate meeting brought together renowned experts representing the main stakeholders (i.e. policy makers, public health authorities, regulatory agencies, pharmaceutical companies and the scientific community at large) to review the global threat of antibiotic resistance and come up with a coordinated set of strategies to fight antimicrobial resistance in a multifaceted approach. We summarize the views of the B-Debate participants regarding the current situation of antimicrobial resistance in animals and the food chain, within the community and the healthcare setting as well as the role of the environment and the development of novel diagnostic and therapeutic strategies, providing expert recommendations to tackle the global threat of antimicrobial resistance.

In Vitro and In Vivo Anticandidal Activity of Human Immunodeficiency Virus Protease Inhibitors

Highly active antiretroviral therapy that includes human immunodeficiency virus (HIV) aspartyl protease inhibitors (PIs) causes a decline in the incidence of some opportunistic infections in AIDS, and this decline is currently attributed to the restoration of specific immunity. The effect of two PIs (indinavir and ritonavir) on the enzymatic activity of a secretory aspartyl protease (Sap) of Candida albicans (a major agent of mucosal disease in HIV-infected subjects) and on growth and experimental pathogenicity of this fungus was evaluated. Both PIs strongly (>/=90%) and dose dependently (0.1-10 microM) inhibited Sap activity and production. They also significantly reduced Candida growth in a nitrogen-limited, Sap expression-dependent growth medium and exerted a therapeutic effect in an experimental model of vaginal candidiasis, with an efficacy comparable to that of fluconazole. Thus, besides the expected immunorestoration, patients receiving PI therapy may benefit from a direct anticandidal activity of these drugs.

Mupirocin Prophylaxis to Prevent Staphylococcus aureus Infection in Patients Undergoing Dialysis: A Meta-analysis

A systematic review of the English-language literature was performed to determine the overall benefit of mupirocin therapy in reducing the rate of Staphylococcus aureus infection among patients undergoing hemodialysis (HD) or peritoneal dialysis (PD). Included studies met the following criteria: they were randomized clinical trials or cohort studies; cohorts consisted of adults (age, > or =18 years) requiring HD or PD; mupirocin therapy was administered to the treatment group, and placebo or no therapy was administered to the control group; and the primary outcome of interest was the difference in the number of S. aureus infections among mupirocin-treated and -untreated patients. Ten studies described in 9 articles were analyzed. A total of 2445 patients were included in the analysis. Use of mupirocin reduced the rate of S. aureus infections by 68% (95% confidence interval [CI], 57%-76%) among all patients undergoing dialysis; risk reductions were 80% (95% CI, 65%-89%) among patients undergoing HD and 63% (95% CI, 50%-73%) among patients undergoing PD. When data were stratified by type of infection, S. aureus bacteremia was found to be reduced by 78% among patients undergoing HD, and peritonitis and exit-site infections were found to be reduced by 66% and 62%, respectively, among patients undergoing PD. Mupirocin prophylaxis substantially reduces the rate of S. aureus infection in the dialysis population. Optimal regimens that minimize the emergence of mupirocin resistance need to be explored.

Role of protease inhibitors in preventing recurrent oral candidosis in patients with HIV infection: a prospective case-control study

This study was conducted to evaluate the efficacy of highly active anti-retroviral therapy (HAART) in preventing recurrence of oral candidosis (OC) associated with HIV. A prospective case-controlled observational study was performed in an inner-city university-hospital HIV/AIDS clinic. Ninety-three HIV-positive study subjects with a history of recurrent OC were divided into two groups: protease inhibitors (PI)-treated patients (group 1, n = 30) and non-PI-treated patients (group 2, n = 63). Study subjects were matched for sex, age, stage of HIV infection, and peripheral CD4+ T-cell counts. The non-PI-treated group was further subdivided into the following three subgroups: HIV-positive study subjects treated with reverse transcriptase inhibitors (RTI; groups 2a and 2c) and HIV-positive study subjects not treated with RTIs (group 2b). Group 2c met the same inclusion criteria as group 2a had but was matched 6 months after the beginning of the study. We also assessed in vitro peripheral blood mononuclear cells (PBMC) and their lymphoproliferative response, as well as cutaneous delayed-type hypersensitivity (DTH) response to Candida-associated antigens in a randomly selected sample of study subjects divided into those treated with PIs and those who were not. During a 1-year follow-up, OC was diagnosed in 2 (7%) PI-treated and 23 (36%) non-PI-treated patients (p<.001). In addition to comparing findings in group 1 with those in group 2c, OC was detected in 14 (50%) non-PI-treated patients compared with no HAART-treated study subjects (p<.001). Only 41% of PI-treated study subjects had positive lymphoproliferative response in PBMCs and none was positive in terms of DTH to Candida antigens (p = not significant versus non-PI-treated study subjects). While objectively demonstrating a beneficial effect of HAART in preventing recurrence of OC infections, our findings suggest this effect cannot be not fully accounted for by reconstitution of anti-Candida cell-mediated immunity, given that other mechanisms, even of a nonimmune nature, could have some effect.

Continuous versus intermittent infusion of vancomycin for the treatment of Gram-positive infections: systematic review and meta-analysis

OBJECTIVES To summarize available evidence on the effect of continuous infusion (CoI) of vancomycin compared with intermittent infusion (InI) in adult patients with Gram-positive infections. METHODS MEDLINE, EMBASE and Cochrane databases were searched. Randomized clinical trials (RCTs) and observational studies that comparatively assessed CoI and InI of vancomycin in terms of mortality, clinical cure, toxicity rates and serum drug exposure [trough concentration (C(min)) for InI and steady-state concentration (C(ss)) for CoI; area under the curve at 24 h (AUC(24)) for both] were included. Meta-analysis was conducted combining and analysing the relative risk (RR) and computing a summary RR of the effects with 95% confidence interval (CI). The standardized mean difference was calculated for continuous outcomes. The I(2) test was calculated to assess heterogeneity across studies. RESULTS One RCT and five observational studies were included in the analysis. Compared with InI, CoI of vancomycin was associated with a significantly lower risk of nephrotoxicity (RR 0.6, 95% CI 0.4-0.9, P = 0.02; I(2)= 0). Overall mortality was not different between the two groups (RR 1.03, 95% CI 0.7-1.6, P = 0.9; I(2)= 0). CONCLUSIONS Our meta-analysis suggests that administration of vancomycin for the treatment of Gram-positive infections by CoI is associated with a significantly lower risk of nephrotoxicity when compared with InI of the drug. RCTs are needed to define the impact on mortality rate and on the pharmacodynamic activity in terms of AUC/MIC ratio.

Rapid screening tests for meticillin-resistant Staphylococcus aureus at hospital admission: systematic review and meta-analysis

Detection and eradication of meticillin-resistant Staphylococcus aureus (MRSA) represents a public health priority worldwide. Our aim was to do a systematic review and meta-analysis of randomised, non-randomised, and observational studies to summarise the available evidence on the effect of MRSA detection by rapid screening tests on hospital-acquired MRSA infections and acquisition rate. Eligible studies were retrieved from Medline, EmBase, Science Citation Index, and the Cochrane database. We judged as eligible those studies that compared hospitals and wards in which active screening for the detection of MRSA carriers was done at hospital admission by use of a rapid molecular test to those in which active screening was done with culture alone or not at all. To account for statistical heterogeneity between studies, random-effects models were used. Ten studies (nine interventional studies and one unblinded, cluster-randomised, crossover trial) were reviewed. Meta-analysis was done for studies reporting data on the same outcome. Primary outcomes included MRSA acquisition rate per 1000 patient-days (four studies); incidence of MRSA bloodstream infections per 1000 patient-days (three studies); and incidence of MRSA surgical-site infections per 100 surgical procedures (five studies). Compared with culture screening, use of rapid screening tests was not associated with a significant decrease in MRSA acquisition rate (risk ratio 0.87, 95% CI 0.61-1.24). Between wards applying rapid screening tests and those not applying screening, we noted a significantly decreased risk for MRSA bloodstream infections (0.54, 95% CI 0.41-0.71), but not for MRSA surgical-site infections (0.69, 95% CI 0.46-1.01). We conclude that active screening for MRSA is more important than the type of test used. Since important and costly decisions, such as mandatory legislation for MRSA universal screening, are under consideration in many countries worldwide, policy makers should be aware of the limits and the heterogeneity of the available evidence.

Combination therapy for carbapenem-resistant Gram-negative bacteria

Carbapenem-resistant Gram-negative bacteria (CR-GNB) represent an increasing hazard in healthcare settings. A central question concerning the treatment of invasive infections caused by CR-GNB involves the use of combination therapy. Potential advantages of combination therapy include improved efficacy due to synergy, while the disadvantages include adverse events and increased antibiotic use with a potential drive towards resistance. Several observational studies have examined whether combination therapy offers an advantage over colistin/polymyxin monotherapy. We highlight the inherent limitations of these studies related to their observational design and sample size to show why they do not at present provide an answer to the question of combination versus monotherapy. This distinction is important to guide clinical practice until solid evidence has been obtained and to enable the recruitment of patients into randomized controlled trials. A few randomized controlled trials examining specific combinations have recently been completed or are ongoing. Currently, however, there is no evidence-based support for most combination therapies against CR-GNB, including colistin/carbapenem combination therapy.

Vancomycin-resistant enterococci (VRE): transmission and control

Transmission of vancomycin-resistant enterococci (VRE) can occur through direct contact with colonised or infected patients or through indirect contact via the hands of health-care workers (HCWs), or via contaminated patient care equipment or environmental surfaces. Antibiotic exposure plays an important role in the transmission dynamic of VRE. Until now, the control measures aimed at reducing the incidence of VRE colonisation and infection in hospitals have included: education of HCWs with implementation of hand-washing practices and compliance; wide and targeted surveillance cultures; isolation of VRE-positive patients; pre-emptive isolation of high-risk patients; and restriction of antibiotic use. However, despite these, VRE is still endemic in many hospitals. The causes of this could be non-compliance with infection control interventions, overuse of antibiotics, and insensitive microbiological methods for detecting VRE in stool. A scoring system using point values has been demonstrated to be useful in reducing rates of nosocomial VRE colonisation. Future prospective comparative studies of infection control approaches in different epidemiological situations might be useful.

Laboratory tools and strategies for methicillin-resistant Staphylococcus aureus screening, surveillance and typing: state of the art and unmet needs

The public health burden caused by methicillin-resistant Staphylococcus aureus (MRSA) infections is now widely recognized, and is a cause of public alarm. Effective MRSA risk management in the healthcare system as well as in the community should rely on accurate detection of reservoirs and sources of transmission, as well as on close monitoring of the impact of interventions on disease incidence and bacterial dissemination. MRSA carrier screening and disease surveillance, coupled with molecular typing, are key information tools for integrated MRSA control and individual risk assessment. These tools should be tailored to the distinct needs of local interventions and national prevention programmes. Surveillance schemes should primarily inform local staff and serve as quality assurance about MRSA risk management. New technologies, including the use of selective culture media and real-time PCR assays, allow faster detection of MRSA carriers upon admission or during stay in healthcare institutions. More research is needed to ascertain their cost-effectiveness for MRSA control. Likewise, tremendous progress has been made concerning molecular typing methods, with optimization and standardization of sequence-based technologies offering broad applicability and high throughput. However, no single S. aureus typing method is yet providing fully reliable information within the range of discrimination needed for public health action. Further refinement of genotyping methods and international harmonization of surveillance and typing schemes must be achieved to facilitate global MRSA control.