Milena M. McLaughlin

Correlations of Antibiotic Use and Carbapenem Resistance in Enterobacteriaceae

ABSTRACT Epidemiological studies have shown a link between carbapenem use and resistance; however, the clinical relationship between antibiotic consumption and the epidemiology of carbapenem-intermediate or -resistant Enterobacteriaceae (CIRE) remains unclear. This study sought to analyze temporal antibiotic consumption trends for relationships with incident CIRE. In total, 310,892 days of therapy and 55 deduplicated CIRE were analyzed. When conservative corrections were applied for multiple comparisons, carbapenem class use and piperacillin-tazobactam use retained significant positive and negative relationships with the incidence of CIRE, respectively.

Quantifying the clinical virulence of Klebsiella pneumoniae producing carbapenemase Klebsiella pneumoniae with a Galleria mellonella model and a pilot study to translate to patient outcomes

BackgroundPrevious studies may have overestimated morbidity and mortality due to Klebsiella pneumoniae producing carbapenemase (KPC) Klebsiella pneumoniae infections because of difficulties in modeling patient comorbidities. This pilot study sought to evaluate KPC virulence by combining clinical and Galleria mellonella models in patients with K. pneumoniae blood stream infections (BSIs).MethodsG. mellonella were inoculated using KPC(+) and KPC(−) isolates from these patients. Extent and rapidity of insect mortality was analyzed. Patients were stratified by KPC BSI status. Clinical outcomes of mortality and length of stay post-infection for survivors (LOS) were analyzed. Median virulence scores calculated from the insect studies were imputed in the clinical model.ResultsThe in-vivo model revealed greater mortality in KPC(−) isolates (p < 0.001). Fifteen patients with KPC(+) BSI were matched with 60 patients with KPC(−) BSI. Hospital mortality was greater in the KPC(+) group versus the KPC(−) group (OR 3.79, 95% CI 1.00 - 14.34). LOS was longer in the KPC(+) group (p < 0.01). Conversely the virulence score attenuated the association between KPC(+) status and mortality and LOS in the final translational models.ConclusionsKPC(+) status was associated with decreased virulence in GM. Opposite findings were observed in patients. This pilot study demonstrates that measured virulence from GM may differ from human estimates of virulence.

A Review of Antibiotic Use in Pregnancy

During pregnancy, untreated sexually transmitted or urinary tract infections are associated with significant morbidity, including low birth weight, preterm birth, and spontaneous abortion. Approximately one in four women will be prescribed an antibiotic during pregnancy, accounting for nearly 80% of prescription medications in pregnant women. Antibiotic exposures during pregnancy have been associated with both short‐term (e.g., congenital abnormalities) and long‐term effects (e.g., changes in gut microbiome, asthma, atopic dermatitis) in the newborn. However, it is estimated that only 10% of medications have sufficient data related to safe and effective use in pregnancy. Antibiotics such as beta‐lactams, vancomycin, nitrofurantoin, metronidazole, clindamycin, and fosfomycin are generally considered safe and effective in pregnancy. Fluoroquinolones and tetracyclines are generally avoided in pregnancy. Physiologic changes in pregnancy lead to an increase in glomerular filtration rate, increase in total body volume, and enhanced cardiac output. These changes may lead to pharmacokinetic alterations in antibiotics that require dose adjustment or careful monitoring and assessment.

High rates of hepatitis C virus (HCV) cure using direct-acting antivirals in HIV/HCV-coinfected patients: a real-world perspective

OBJECTIVES There are few data on the real-world experience of FDA-approved oral hepatitis C virus (HCV) direct-acting antiviral (DAA) drug combinations in HIV/HCV-coinfected patients. We evaluated the safety and efficacy of DAA therapies in a cohort of HIV/HCV patients in a large urban clinic in Chicago. METHODS HIV/HCV-coinfected adults (≥18 years) enrolled in the Northwestern University Viral Hepatitis Registry between January 2013 and June 2015 were analysed. Treated patients received one of the following DAA combinations: sofosbuvir/ledipasvir, sofosbuvir/ribavirin, sofosbuvir/simeprevir or paritaprevir/ritonavir/ombitasvir/dasabuvir ± ribavirin. The primary outcome was sustained virological response at 12 weeks after DAA completion (SVR12). RESULTS Seventy-seven HIV/HCV patients were evaluated for DAA therapy. Most patients were male (62/77, 81%) and infected with HCV genotype 1 (67/77, 87%). Some 32/77 (42%) were cirrhotic and 29/77 (38%) had received prior treatment with an IFN-containing regimen. DAA therapy was more likely to be started in Caucasians than persons of other ethnicities (P = 0.01). The overall SVR12 rate was 92% in 52 patients who completed therapy and had follow-up by the end of the study: sofosbuvir/simeprevir, 32/33 (97%); sofosbuvir/ribavirin, 4/7 (57%); sofosbuvir/ledipasvir, 11/11 (100%); and paritaprevir/ritonavir/ombitasvir/dasabuvir, 1/1 (100%). Four patients relapsed after therapy with sofosbuvir/simeprevir (n = 1) or sofosbuvir/ribavirin (n = 3). Adverse events were uncommon and did not result in DAA treatment interruption or discontinuation. CONCLUSIONS The HCV DAA combinations of sofosbuvir/ledipasvir and sofosbuvir/simeprevir were highly effective and well tolerated in this diverse population of HIV/HCV-coinfected patients, many of whom had advanced liver disease. HIV coinfection should not be considered a barrier to successful HCV treatment with DAAs.

Peramivir: an intravenous neuraminidase inhibitor.

Introduction: Peramivir (BCX-1812, RWJ-270201) is a highly selective inhibitor of influenza A and B neuraminidase that has recently been approved in the USA by the FDA to treat acute, uncomplicated influenza in adults. Areas covered: This review examines the discovery and development of peramavir as well as its role in the treatment of influenza. Peramivir is currently the only FDA-approved anti-influenza agent that can be given as an intravenous injection, granting it a unique role in therapy with the potential to improve adherence and outcomes in patients who are unable to tolerate oral agents. In vitro, animal, human and safety data are presented as well as information regarding special populations, resistance and drug approval. Expert opinion: Clinical trial data support the use of peramivir to relieve influenza symptoms in acute, uncomplicated influenza, with improvements over placebo similar to those of other approved anti-influenza treatments. The ability to give a one-time injectable dose offers improved adherence over currently available oral regimens. While not approved for hospitalized patients, available data suggest that multiple dose peramivir may also have a role in treatment of severally ill, hospitalized patients. Supportive data for the use of peramivir in special patient populations such as pediatrics and those especially at-risk to develop severe influenza symptoms are promising; however, they require further study.

Desirable Characteristics of Hepatitis C Treatment Regimens: A Review of What We Have and What We Need.

There have been dramatic advancements in the treatment of chronic hepatitis C (HCV) infection. This is largely due to the approval of several direct-acting antiviral agents (DAAs) from a variety of medication classes with novel mechanisms of action. These therapies are a welcomed advancement given their improved efficacy and tolerability compared to pegylated interferon and ribavirin (RBV)-based regimens. These convenient, all-oral regimens treat a variety of genotypes and often offer high cure rates in a variety of HCV-infected populations. While there are several benefits associated with these therapies, there are also notable shortcomings. Shortcomings include diminished response or need for adjunctive RBV in difficult-to-treat populations (decompensated cirrhosis, active substance abuse patients, advanced kidney disease, etc.), activity against select genotypes, substantial drug–drug interaction potential, and high cost. Therefore, while current DAA-based therapies have several favorable attributes, each also has its limitations. The purpose of this review is to (1) identify the characteristics of an ideal HCV treatment regimen, (2) describe desirable features of existing regimens, (3) summarize limitations of existing regimens, and (4) introduce promising emerging therapies. This manuscript will serve as a guide for evaluating the caliber of future HCV treatment regimens.

Pharmacodynamic Target Attainment for Various Ceftazidime Dosing Schemes in High-flux Hemodialysis

ABSTRACT Ceftazidime is a broad-spectrum cephalosporin with high-level activity against a variety of Gram-negative pathogens, including Pseudomonas aeruginosa. Improved outcomes are associated with cumulative percentages of a 24-h period that the drug concentration exceeds the MIC under steady-state pharmacokinetic conditions (%TMIC) of >45 to 70% of the dosing interval. Optimal dosing to achieve a 90% probability of target attainment (PTA) in patients receiving high-flux hemodialysis (HFHD) is unknown. We used existing data from six anephric adults receiving hemodialysis to construct a population model with the Pmetrics package for R. From the final models joint probability density, we simulated the PTA for various ceftazidime dosing regimens, HFHD schedules, and organism MICs. For HFHD every 48 h and 1 g of ceftazidime given posthemodialysis, the PTA exceeds 90% for all isolates with MICs of ≤8 μg/ml, assuming a goal of 70%TMIC. For 72-h dialysis intervals, postdialysis dosing of 1 g is adequate for achievement of the 70%TMIC goal only for organisms with MICs of ≤4 μg/ml, while 2 g is adequate for organisms with MICs of ≤8 μg/ml. A dose of 500 mg once daily, regardless of HFHD schedule, has a 90% PTA for organisms with MICs of ≤16 μg/ml, while 1 g once daily may achieve 100% PTA even for resistant organisms with a MIC of 32 μg/ml. Therefore, to ensure maximal ceftazidime activity, once-daily dosing of 500 mg to 1 g ceftazidime in patients receiving HFHD may be preferable for critically ill patients when MIC data are unavailable and for more resistant organisms with ceftazidime MICs of 16 to 32 μg/ml.

Evaluation of clinical outcomes in patients with Gram-negative bloodstream infections according to cefepime MIC.

Predicted and observed failures at higher cefepime MICs have prompted the Clinical and Laboratories Standards Institute (CLSI) to lower the susceptible breakpoint for Enterobacteriaceae to ≤2mg/L, with dose-dependent susceptibility at 4-8mg/L, while the susceptibility breakpoint for nonfermentative organisms remain unchanged at ≥8mg/L. The contribution of increasing cefepime MIC to mortality risk in the setting of aggressive cefepime dosing is not well defined. Patients who were treated with cefepime for Gram-negative blood stream infections (GNBSIs), including both Enterobacteriaceae and nonfermentative organisms, were screened for inclusion in this retrospective cohort study. Demographic and microbiologic variables were collected, including pathogen, cefepime MIC, dosage, and interval. The objective was to define a risk-adjusted mortality breakpoint for cefepime MICs. Secondarily, we looked at time to death and length of stay (LOS) postculture. Ninety-one patients were included in the analysis. Overall, 19 patients died and 72 survived. Classification and Regression Tree analysis identified an inhospital mortality breakpoint at a cefepime MIC between 2 and 4mg/L for patients with a modified Acute Physiology and Chronic Health Evaluation II score ≤16.5 (4.2% versus 25%, respectively). Multivariate logistic regression revealed increased odds of mortality at a cefepime MIC of 4mg/L (adjusted odds ratio [aOR] 6.47; 95% confidence interval [CI] 1.25-33.4) and 64mg/L (aOR 6.54, 95% CI 1.03-41.4). Those with cefepime MICs ≥4mg/L experienced a greater median intensive care unit LOS for survivors (16 versus 2days; P=0.026). Increasing cefepime MIC appears to predict inhospital mortality among patients who received aggressive doses of cefepime for GNBSIs, supporting a clinical breakpoint MIC of 2mg/L.

Antiretroviral Pharmacokinetics in Pregnant Women.

For women infected with the human immunodeficiency virus (HIV) who become pregnant, the use of combination antiretroviral therapy (ART) significantly reduces transmission of HIV from mother to child. Selection of an appropriate ART regimen for use among pregnant women requires consideration of numerous factors including maternal and fetal safety, antiretroviral pharmacokinetics, and regimen efficacy. Optimization of antiretroviral pharmacokinetics during pregnancy requires special consideration because pregnancy‐associated changes in drug absorption, distribution, metabolism, and excretion are known to occur throughout pregnancy and postpartum. Understanding antiretroviral placental transfer may offer additional insight into each drugs potential role in preventing HIV transmission in utero and may also have implications regarding viral resistance in cases where transmission does occur. In this review, we summarize key published data describing antiretroviral pharmacokinetics in pregnant women, providing suggestions for clinical application of these data where appropriate.

Projections for antiinfective drug shortages and time to actual resolution

PURPOSE The results of a national study of projected versus actual times to resolution of temporary U.S. shortages of antiinfective drugs are presented. METHODS Descriptive data on antiinfective drug shortages, including differences between manufacturer-estimated and actual times to shortage resolution, were collected over a one-year period via regular monitoring of the websites of ASHP and the Food and Drug Administration. Inventory data from one large hospital in the Midwest were collected in order to characterize realized shortages (i.e., those for which mitigation was required). RESULTS During the study period, there were 47 transient shortages of antiinfective medications involving 381 unique products or formulations, of which 40% (n = 19) were emergent shortages. Generic-only and brand-only medications accounted for 53% (n = 25) and 21% (n = 10) of the evaluated shortages, respectively; the median shortage duration was 40 days (interquartile range [IQR], 22-91 days). The reasons for shortages most frequently cited by manufacturers were product or formulation discontinuation (21%), increased demand (12%), and raw material shortfalls (8%). Some shortages were resolved sooner than originally projected, but overall, actual shortage durations exceeded manufacturer-projected durations by a median of 17 days (IQR, 0-52.5 days). Ten realized shortages occurred at the hospital study site, compelling the antimicrobial stewardship team to recommend alternative therapies or restrict the use of drugs in short supply. CONCLUSION The actual durations of evaluated antiinfective drug shortages during the study period were longer than the manufacturer-projected durations by a median of 17 days.