Archive for July 25, 2016

Carbapenemases in Klebsiella pneumoniae and Other Enterobacteriaceae: an Evolving Crisis of Global Dimensions

Clin. Microbiol. Rev. October 2012 25(4): 682-707

S. Tzouvelekis, A. Markogiannakis, M. Psichogiou, P. T. Tassios, and G. L. Daikos

aDepartment of Microbiology

cFirst Department of Propaedeutic Medicine, School of Medicine, University of Athens

bDepartment of Pharmacy, Laiko General Hospital, Athens, Greece

The spread of Enterobacteriaceae, primarily Klebsiella pneumoniae, producing KPC, VIM, IMP, and NDM carbapenemases, is causing an unprecedented public health crisis. Carbapenemase-producing enterobacteria (CPE) infect mainly hospitalized patients but also have been spreading in long-term care facilities. Given their multidrug resistance, therapeutic options are limited and, as discussed here, should be reevaluated and optimized. Based on susceptibility data, colistin and tigecycline are commonly used to treat CPE infections. Nevertheless, a review of the literature revealed high failure rates in cases of monotherapy with these drugs, whilst monotherapy with either a carbapenem or an aminoglycoside appeared to be more effective. Combination therapies not including carbapenems were comparable to aminoglycoside and carbapenem monotherapies. Higher success rates have been achieved with carbapenem-containing combinations. Pharmacodynamic simulations and experimental infections indicate that modification of the current patterns of carbapenem use against CPE warrants further attention. Epidemiological data, though fragmentary in many countries, indicate CPE foci and transmission routes, to some extent, whilst also underlining the lack of international collaborative systems that could react promptly and effectively. Fortunately, there are sound studies showing successful containment of CPE by bundles of measures, among which the most important are active surveillance cultures, separation of carriers, and assignment of dedicated nursing staff.


July 25, 2016 at 6:26 pm

Combination Therapy for Treatment of Infections with Gram-Negative Bacteria

Clin. Microbiol. Rev. July 2012 25(3): 450-470

Pranita D. Tamma, Sara E. Cosgrove, and Lisa L. Maragakis

aThe Johns Hopkins Medical Institutions, Department of Medicine, Division of Pediatric Infectious Diseases, Baltimore, Maryland, USA

bThe Johns Hopkins Medical Institutions, Department of Medicine, Division of Infectious Diseases, Baltimore, Maryland, USA

Combination antibiotic therapy for invasive infections with Gram-negative bacteria is employed in many health care facilities, especially for certain subgroups of patients, including those with neutropenia, those with infections caused by Pseudomonas aeruginosa, those with ventilator-associated pneumonia, and the severely ill. An argument can be made for empiric combination therapy, as we are witnessing a rise in infections caused by multidrug-resistant Gram-negative organisms. The wisdom of continued combination therapy after an organism is isolated and antimicrobial susceptibility data are known, however, is more controversial. The available evidence suggests that the greatest benefit of combination antibiotic therapy stems from the increased likelihood of choosing an effective agent during empiric therapy, rather than exploitation of in vitro synergy or the prevention of resistance during definitive treatment. In this review, we summarize the available data comparing monotherapy versus combination antimicrobial therapy for the treatment of infections with Gram-negative bacteria.


July 25, 2016 at 6:19 pm

Predictors of Mortality in Staphylococcus aureus Bacteremia

Clin. Microbiol. Rev. April 2012 25(2): 362-386

Sebastian J. van Hal, Slade O. Jensen, Vikram L. Vaska, Björn A. Espedido, David L. Paterson, and Iain B. Gosbell

aDepartment of Microbiology and Infectious Diseases, Sydney South West Pathology Service—Liverpool, South Western Sydney Local Health Network, Sydney, New South Wales, Australia

bAntibiotic Resistance and Mobile Elements Group, Microbiology and Infectious Diseases Unit, School of Medicine, University of Western Sydney, Sydney, New South Wales, Australia

cIngham Institute of Applied Medical Research, Sydney, New South Wales, Australia

dThe University of Queensland, UQ Centre for Clinical Research (UQCCR), Herston, Queensland, Australia

Staphylococcus aureus bacteremia (SAB) is an important infection with an incidence rate ranging from 20 to 50 cases/100,000 population per year. Between 10% and 30% of these patients will die from SAB. Comparatively, this accounts for a greater number of deaths than for AIDS, tuberculosis, and viral hepatitis combined. Multiple factors influence outcomes for SAB patients. The most consistent predictor of mortality is age, with older patients being twice as likely to die. Except for the presence of comorbidities, the impacts of other host factors, including gender, ethnicity, socioeconomic status, and immune status, are unclear. Pathogen-host interactions, especially the presence of shock and the source of SAB, are strong predictors of outcomes. Although antibiotic resistance may be associated with increased mortality, questions remain as to whether this reflects pathogen-specific factors or poorer responses to antibiotic therapy, namely, vancomycin. Optimal management relies on starting appropriate antibiotics in a timely fashion, resulting in improved outcomes for certain patient subgroups. The roles of surgery and infectious disease consultations require further study. Although the rate of mortality from SAB is declining, it remains high. Future international collaborative studies are required to tease out the relative contributions of various factors to mortality, which would enable the optimization of SAB management and patient outcomes.


July 25, 2016 at 6:17 pm

Epidemiology of and Diagnostic Strategies for Toxoplasmosis

Clin. Microbiol. Rev. April 2012 25(2): 264-296

Florence Robert-Gangneux and Marie-Laure Dardé

aService de Parasitologie, Faculté de Médecine et Centre Hospitalier Universitaire de Rennes, Rennes, France

bINSERM U1085, IRSET (Institut de Recherche en Santé Environnement Travail), Université Rennes 1, Rennes, France

cCentre National de Référence (CNR) Toxoplasmose/Toxoplasma Biological Resource Center (BRC), Laboratoire de Parasitologie-Mycologie, Centre Hospitalier-Universitaire Dupuytren, Limoges, France

dINSERM U1094, Tropical Neuroepidemiology, Limoges, France, Université Limoges School of Medicine, Institute of Neuroepidemiology and Tropical Neurology, Limoges, France, and CNRS FR 3503 GEIST, CHU Limoges, Limoges, France

The apicomplexan parasite Toxoplasma gondii was discovered a little over 100 years ago, but knowledge of its biological life cycle and its medical importance has grown in the last 40 years. This obligate intracellular parasite was identified early as a pathogen responsible for congenital infection, but its clinical expression and the importance of reactivations of infections in immunocompromised patients were recognized later, in the era of organ transplantation and HIV infection. Recent knowledge of host cell-parasite interactions and of parasite virulence has brought new insights into the comprehension of the pathophysiology of infection. In this review, we focus on epidemiological and diagnostic aspects, putting them in perspective with current knowledge of parasite genotypes. In particular, we provide critical information on diagnostic methods according to the patient’s background and discuss the implementation of screening tools for congenital toxoplasmosis according to health policies.




Page 280, Fig. 5: The center box in the top row for the nonimmunized women should read “IgG−IgM−.”

July 25, 2016 at 6:15 pm

Stenotrophomonas maltophilia: an Emerging Global Opportunistic Pathogen

Clin. Microbiol. Rev. January 2012 25(1): 2-41

Joanna S. Brooke

Department of Biological Sciences, DePaul University, Chicago, Illinois, USA

Stenotrophomonas maltophilia is an emerging multidrug-resistant global opportunistic pathogen. The increasing incidence of nosocomial and community-acquired S. maltophilia infections is of particular concern for immunocompromised individuals, as this bacterial pathogen is associated with a significant fatality/case ratio. S. maltophilia is an environmental bacterium found in aqueous habitats, including plant rhizospheres, animals, foods, and water sources. Infections of S. maltophilia can occur in a range of organs and tissues; the organism is commonly found in respiratory tract infections. This review summarizes the current literature and presents S. maltophilia as an organism with various molecular mechanisms used for colonization and infection. S. maltophilia can be recovered from polymicrobial infections, most notably from the respiratory tract of cystic fibrosis patients, as a cocolonizer with Pseudomonas aeruginosa. Recent evidence of cell-cell communication between these pathogens has implications for the development of novel pharmacological therapies. Animal models of S. maltophilia infection have provided useful information about the type of host immune response induced by this opportunistic pathogen. Current and emerging treatments for patients infected with S. maltophilia are discussed.


July 25, 2016 at 6:13 pm

2016-07-14 Guidelines for the Use of Antiretroviral Agents in HIV-1-Infected Adults and Adolescents

Key Updates

What to Start: Initial Combination Regimens for the Antiretroviral-Naive Patient

The approval of 3 fixed-dose combination products containing tenofovir alafenamide (an oral prodrug of tenofovir) and emtricitabine (TAF/FTC) prompted several changes in the What to Start section. The key changes are highlighted below:

– TAF/FTC was added as a 2-NRTI option in several Recommended and Alternative regimens, as noted in Table 6 of the guidelines. The addition of TAF/FTC to these recommendations is based on data from comparative trials demonstrating that TAF-containing regimens are as effective in achieving or maintaining virologic suppression as tenofovir disoproxil fumarate (TDF)-containing regimens and with more favorable effects on markers of bone and renal health.

– In the What to Start section, the evidence quality rating “II” was expanded to include “relative bioavailability/bioequivalence studies or regimen comparisons from randomized switch studies.” This evidence rating was broadened because not all recommended regimens were evaluated in randomized, controlled trials in antiretroviral therapy (ART)-naive patients. The Panel on Antiretroviral Guidelines for Adults and Adolescents (the Panel) based their recommendations for some regimens on either data from bioequivalence or relative bioavailability studies, or by extrapolating results from randomized “switch” studies that evaluated a drug’s or regimen’s ability to maintain virologic suppression in patients whose HIV was suppressed on a previous regimen. Guidance for clinicians on choosing between abacavir (ABC)-, TAF-, and TDF-containing regimens was added to What to Start.

– The lopinavir/ritonavir (LPV/r) plus 2-NRTI regimen was removed from the list of Other regimens because regimens containing this protease inhibitor (PI) combination have a larger pill burden and greater toxicity than other currently available options.

Regimen Switching

– Based on the most current data, this section was simplified to focus on switch strategies for virologically suppressed patients. The strategies are categorized as Strategies with Good Supporting Evidence, Strategies Under Evaluation, and Strategies Not Recommended.

HIV-Infected Women

– The Panel emphasizes that ART is recommended for all HIV-infected patients, including all HIV-infected women.

– The Panel also stresses the importance of early treatment for HIV-infected women during pregnancy and continuation of ART after pregnancy.

– This section was updated to include new data on interactions between antiretroviral (ARV) drugs and hormonal contraceptives.

Hepatitis B Virus (HBV)/HIV Coinfection

– This section was updated to include TAF/FTC as a treatment option for patients with HBV/HIV coinfection. Data on the virologic efficacy of TAF for the treatment of HBV in persons without HIV infection and TAF/FTC in persons with HBV/HIV coinfection are discussed.

– The Panel no longer recommends adefovir or telbivudine as options for HBV/HIV coinfected patients, as there is limited safety and efficacy data on their use in this population. In addition, these agents have a higher incidence of toxicities than other recommended treatments.

Hepatitis C Virus (HCV)/HIV Coinfection

– The text and Table 12 in this section were updated with information regarding the potential pharmacokinetic (PK) interactions between different ARV drugs and the recently approved hepatitis C drugs daclatasvir and the fixed-dose combination product of elbasvir and grazoprevir.

– Peginterferon alfa and ribavirin were removed from Table 12, as these agents do not have significant PK interactions with ARV drugs.

Tuberculosis (TB)/HIV Coinfection

– This section was updated to include a discussion on the treatment of latent tuberculosis infection (LTBI) in HIV-infected persons. The added discussion notes that a 12-week course of once-weekly rifapentine and isoniazid is an option for patients receiving either an efavirenz (EFV)- or a raltegravir (RAL)-based regimen.

– This section addresses the data from the TEMPRANO and START studies demonstrating a potential role of ART in reducing TB disease.

The recommendations and discussion regarding when to initiate ART in patients with active TB were simplified.

– As rifamycins are potent inducers of P-glycoprotein (P-gp), and TAF is a P-gp substrate, coadministration of TAF and rifamycins is not recommended.

Additional Updates

Minor revisions were made to the following sections:

– Laboratory Testing for Initial Assessment and Monitoring of HIV-Infected Patients on Antiretroviral Therapy

– Drug Resistance Testing

– Adverse Effects of Antiretroviral Agents and Tables 14 and 15

– Monthly Average Wholesale Price of Commonly Used Antiretroviral Drugs (Table 16)

– Drug Interaction Tables 18, 19a-e, and 20b

– Drug Characteristics Tables (Appendix B, Tables 1–7)



July 25, 2016 at 2:17 pm


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