Vancomycin Recipients Research Articles

1344. Ridinilazole (RDZ) for Clostridium difficile Infection (CDI): Impact of Diagnostic Method on Outcomes From a Phase 2 Clinical Trial

BackgroundDiagnosis of CDI includes fecal detection of a C. difficile toxigenic strain (TS) or free toxins (FT). TS detection does not distinguish infection from colonization. Guidelines recommend an FT test be part of diagnostic algorithms. Here we report outcome differences, based on diagnostic method at enrollment, from a Phase 2 clinical trial of RDZ, a novel CDI antibiotic designed to treat CDI and reduce recurrence of CDI (rCDI).MethodsThis double-blind study randomized 100 patients 1:1 to 10 days RDZ 200 mg BID or vancomycin (VAN) 125 mg QID treatment. Subjects were enrolled with CDI symptoms and a positive diagnostic result (FT or TS). Baseline (BL) stool samples were assessed for the presence of FT. All subjects entered the intent to treat (ITT) population; those subjects positive for FT entered a modified ITT (mITT), the primary analysis population. Primary endpoint was sustained clinical response (SCR) defined as cure at end of therapy and no rCDI for the next 30 days. rCDI was defined as CDI symptoms, a positive diagnostic test and need for therapy; a sensitivity analysis considered positive FT rCDI cases. BL fecal concentrations of lactoferrin and calprotectin were determined by enzyme immunoassay.ResultsOf 100 subjects enrolled, 69 (36 RDZ: 33 VAN) were FT positive at BL. RDZ compared with VAN recipients had improved SCR rates via reduced rCDI. Absolute differences in SCR between RDZ and VAN (prespecified 90% CI) for MITT (FT positive) and ITT subjects were 24.3% (3.1, 39.1) and 14.0% (−1.8, 28.8), respectively. Absolute SCR differences between the MITT and ITT subjects from the sensitivity analysis were 26.2% (4.6, 40.6) and 14.3% (−1.7, 29.1). Median BL calprotectin and lactoferrin levels (µg/mL) were significantly higher for FT positive subjects at 1,002 and 87, than for FT negative subjects at 53 and 4, respectively.ConclusionRDZ showed improved SCR in comparison with VAN. Treatment differences were greater in MITT subjects. Lower SCR improvement in RDZ ITT subjects is likely due to enrollment of some colonized rather than infected subjects; this explanation is supported by higher calprotectin and lactoferrin levels in FT-positive samples. These data demonstrate the importance of FT testing in-line with CDI guideline recommendations.Disclosures R. Vickers, Summit Therapeutics: Employee, Salary and Stock options. S. Chowdhury, Summit Therapeutics: Employee, Salary and Stock options. M. Wilcox, Summit Therapeutics: Consultant, Research Contractor and Scientific. Advisor, Consulting fee, Research grant and Research support.

Efficacy and safety of intravenous daptomycin in Japanese patients with skin and soft tissue infections

Daptomycin is a lipopeptide antibiotic active against gram-positive organisms and recently approved for marketing in Japan. This study investigates the efficacy and safety of daptomycin in Japanese patients with skin and soft tissue infections (SSTIs) caused by methicillin-resistant Staphylococcus aureus (MRSA) for regulatory filing in Japan. Overall, 111 Japanese patients with SSTI were randomized in this open-label, randomized, active-comparator controlled, parallel-group, multicenter, phase III study. Patients received intravenous daptomycin 4 mg/kg once daily or vancomycin 1 g twice daily for 7–14 days. Efficacy was determined by a blinded Efficacy Adjudication Committee. Among patients with SSTIs caused by MRSA, 81.8 % (95 % CI, 69.1–90.9) of daptomycin recipients and 84.2 % (95 % CI, 60.4–96.6) of vancomycin recipients achieved a successful clinical response at the test-of-cure (TOC) visit. The microbiological success rate against MRSA at the TOC visit was 56.4 % (95 % CI, 42.3–69.7) with daptomycin and 47.4 % (95 % CI, 24.4–71.1) with vancomycin. Daptomycin was generally well tolerated; most adverse events were of mild to moderate severity. The measurement of daptomycin concentration in plasma revealed that patients with mild or moderate impaired renal function showed similar pharmacokinetics profiles to patients with normal renal function. Clinical and microbiological responses, stratified by baseline MRSA susceptibility, suggested that patients infected with MRSA of higher daptomycin MIC showed a trend of lower clinical success with a P value of 0.052 by Cochran–Armitage test. Daptomycin was clinically and microbiologically effective for the treatment of MRSA-associated SSTIs in Japanese patients.

Is “Drug-Induced” Linear IgA Bullous Dermatosis a Separate Entity?

In the 1970s, linear IgA bullous dermatosis (LABD) was first described and differentiated from bullous pemphigoid and dermatitis herpetiformis, which have some overlapping features. In the 1980s, the drug vancomycin was pointed to as a causative agent. Most vancomycin recipients also take many other agents, which calls into question its role in LABD. Fortuna and colleagues reviewed the English-language literature on drug-induced LABD published …

Clinical Outcomes of Linezolid vs Vancomycin in Methicillin-Resistant Staphylococcus aureus Ventilator-Associated Pneumonia

Vancomycin has been the treatment standard for methicillin-resistant Staphylococcus aureus (MRSA) infections, but clinical efficacy is limited. We report outcomes of a cohort with MRSA ventilator-associated pneumonia (VAP) treated with vancomycin vs linezolid. Retrospective analysis of 113 participants with MRSA VAP confirmed by bronchoscopy who have been initiated on therapy with either vancomycin or linezolid within 24 hours after bronchoscopy and completed ≥7 days of therapy during their hospitalization from July 2003 to June 2007. The primary endpoints were hospital survival and clinical cure, defined as resolution of signs and symptoms of VAP or microbiological eradication after completion of therapy along with clinical pulmonary infection score (CPIS) ≤6 at day 7 of therapy. At hospital discharge, 23/27 (85.2%) of linezolid and 72/86 (83.7%) of vancomycin recipients had survived (P = .672). In comparison to linezolid recipients, the adjusted odds ratio (OR) for survival was 0.72 (95% confidence interval [CI]: 0.16-3.27) with vancomycin therapy. Clinical cure was achieved in 24/27 (88.9%) of linezolid and 63/86 (73.3%) of vancomycin recipients (P = .066). Compared to linezolid recipients, the adjusted OR for clinical cure was 0.24 (95% CI: 0.05-1.10) with vancomycin therapy. Survival and clinical cure did not differ significantly between vancomycin recipients with trough level ≥15 and <15 μg/mL, respectively. Our results suggested no survival benefit but a trend toward higher cure rate with linezolid therapy. The optimal treatment of MRSA VAP requires further study through randomized, controlled trials.

Telavancin

Telavancin is the first available lipoglycopeptide antibacterial agent. It is active against Gram-positive bacteria, including meticillin/oxacillin-resistant Staphylococcus aureus (MRSA) strains associated with complicated skin and skin structure infections (cSSSIs). In randomized, double-blind trials, intravenous telavancin 10 mg/kg once daily (administered as a 1-hour infusion) was effective in the treatment of adult patients with cSSSIs, including those with infections caused by MRSA, as shown by clinical cure rates in clinically evaluable, all-treated and microbiologically evaluable populations at the test-of-cure (TOC) visit. Telavancin 10 mg/kg once daily was noninferior to intravenous vancomycin 1 g every 12 hours, with clinical cure rates of 88% versus 87% at the TOC visit in pooled data from the clinically evaluable population (n = 1489) of two phase III trials. Pooled clinical cure rates in telavancin recipients at the TOC visit were also not significantly different from those in vancomycin recipients in the all-treated or microbiologically evaluable populations, including microbiologically evaluable subgroups with baseline infections caused by MRSA, meticillin-susceptible S. aureus or other Gram-positive pathogens. Telavancin was generally well tolerated in patients with cSSSIs, with most adverse events being of mild or moderate severity.

Initial Low‐Dose Gentamicin forStaphylococcus aureusBacteremia and Endocarditis Is Nephrotoxic

The safety of adding initial low-dose gentamicin to antistaphylococcal penicillins or vancomycin for treatment of suspected Staphylococcus aureus native valve endocarditis is unknown. This study evaluated the association between this practice and nephrotoxicity. We performed a prospective cohort study of safety data from a randomized, controlled trial of therapy for S. aureus bacteremia and native valve infective endocarditis involving 236 patients from 44 hospitals in 4 countries. Patients either received standard therapy (antistaphylococcal penicillin or vancomycin) plus initial low-dose gentamicin (n=116) or received daptomycin monotherapy (n = 120). We measured renal adverse events and clinically significant decreased creatinine clearance in patients (1) in the original randomized study arms and (2) who received any initial low-dose gentamicin either, as a study medication or <or= days before enrollment. Renal adverse events occurred in 8 (7%) of 120 daptomycin recipients, 10 (19%) of 53 vancomycin recipients, and 11 (17%) of 63 antistaphylococcal penicillin recipients. Decreased creatinine clearance occurred in 9 (8%) of 113 of evaluable daptomycin recipients, 10 (22%) of 46 vancomycin recipients, and 16 (25%) of 63 antistaphylococcal penicillin recipients. An additional 21 patients received initial low-dose gentamicin <or=2 days before study enrollment. A total of 22% of patients who received initial low-dose gentamicin versus 8% of patients who did not receive initial low-dose gentamicin experienced decreased creatinine clearance (P = 005 ). Independent predictors of a clinically significant decrease in creatinine clearance were age >or=65 years and receipt of any initial low-dose gentamicin. Initial low-dose gentamicin as part of therapy for S. aureus bacteremia and native valve infective endocarditis is nephrotoxic and should not be used routinely, given the minimal existing data supporting its benefit.

Linezolid versus vancomycin for Staphylococcus aureus bacteraemia: pooled analysis of randomized studies

To compare outcomes in patients with Staphylococcus aureus bacteraemia treated with linezolid with those of vancomycin-treated patients. We pooled and analysed five randomized studies comparing linezolid with vancomycin, focusing on the 144 adults with S. aureus bacteraemia, which was secondary in >70% of patients. Efficacy variables were clinical cure of primary infection, microbiological success (eradication of S. aureus from blood or presumed eradication based on clinical cure of primary infection), survival, and outcome predictors identified by multivariate logistic regression. Of 99 clinically evaluable patients, primary infection was cured in 28 (55%) of 51 linezolid recipients and 25 (52%) of 48 vancomycin recipients [odds ratio (OR) for cure with linezolid versus vancomycin, 1.12; 95% confidence interval (CI), 0.51-2.47]. There were no between-group differences in the meta-analysis (OR, 1.16; 95% CI, 0.5-2.65). Of 53 evaluable patients with methicillin-resistant S. aureus (MRSA) bacteraemia, clinical cure occurred in 14 (56%) of 25 linezolid recipients and 13 (46%) of 28 vancomycin recipients (OR, 1.47; 95% CI, 0.50-4.34). Microbiological success occurred in 41 (69%) of 59 linezolid recipients and 41 (73%) of 56 vancomycin recipients (OR, 0.83; 95% CI, 0.37-1.87). Fifty-five (74%) of 74 linezolid recipients survived versus 52 (74%) of 70 vancomycin recipients (OR, 1.00; 95% CI, 0.47-2.12). In the multivariate analysis, treatment group was not a significant predictor of clinical cure or survival. Linezolid was associated with outcomes that were not inferior to those of vancomycin in patients with secondary S. aureus bacteraemia.

The role of vancomycin in the persistence or recurrence of Staphylococcus aureus bacteraemia

Persistence and recurrence of Staphylococcus aureus bacteraemia (SAB) have been linked primarily with difficult-to-eradicate foci of infection such as endocarditis, osteomyelitis or abscess formation. Although vancomycin therapy has been suggested as a predictor of relapse of SAB, it has never been shown to be associated with persistent SAB. The purpose of this study was to examine the possible association of vancomycin therapy and persistence of SAB. Two groups of patients were retrospectively studied. One group consisted of 124 patients who completed > or =10 d of appropriate anti-staphylococcal therapy (from among a total of 284 patients with SAB during 2 y, 1997-8). In this group, persistence of SAB (methicillin resistant and susceptible combined) for >3 d while on therapy, occurred in 11 (22%) of 55 vancomycin recipients and in none of 52 cloxacillin recipients (p = 0.002). When calculated for methicillin susceptible SAB alone, the numbers were 3 of 13 vs 0 of 52, respectively (p = 0.007). The second study group included all patients with persistence and/or relapse of SAB while on appropriate anti-staphylococcal therapy during 4 y (1997-2000). In this group, the persistence occurred while on vancomycin therapy, in 32 (94%) of 34 patients with >3 d of persistence of SAB. In the majority of these patients a secondary focus of infection serving as the site of persistence was identified in addition to the primary focus (or portal of entry). It was concluded that vancomycin is inferior to cloxacillin therapy in terminating SAB and therefore may predispose to prolonged bacteraemia and secondary seeding of infection during therapy.

Absence of "red man syndrome" in patients being treated with vancomycin or high-dose teicoplanin

Twenty-five febrile patients with a history of intravenous drug use who were receiving either vancomycin (15 patients) or teicoplanin (10 patients) as part of a multicenter, double-blind, randomized, clinical efficacy trial were enrolled, upon receipt of their first dose of antibiotic, into a study to evaluate the effect of 1 g of vancomycin and high-dose teicoplanin (30 mg/kg of body weight) on histamine release and the occurrence of "red man syndrome" (RMS). In addition, 10 healthy volunteer subjects (HVS) were randomized to receive either 1 g of vancomycin intravenously or a saline infusion in a double-blind, crossover design study. Patients and HVS were observed for the presence of erythema, flushing, pruritus, and hypotension during and for up to 1 h postinfusion by a blinded investigator. Histamine concentrations in plasma were measured at baseline and during and after drug infusion. No significant differences were noted in baseline temperature between patients (vancomycin recipients, 102.3 degrees F [39.1 degrees C]; teicoplanin recipients, 102.4 degrees F [39.1 degrees C]) or incidence of bacteremia (7 of 15 vancomycin recipients; 5 of 10 teicoplanin recipients). There were no significant differences in peak vancomycin concentrations in the sera of patients (40.8 micrograms/ml) and HVS (49.9 micrograms/ml). There were no reactions consistent with RMS in any patient who received teicoplanin (0 of 10); there was a significant difference in the occurrence of RMS in patients in comparison with that in HVS (0 of 15 patients, 9 of 10 HVS; P less than 0.001) who received vancomycin. The predominant reaction was erythema and pruritus. Histamine concentrations in plasma and the area under the histamine plasma concentration-time curve were highly variable within groups and were not statistically different between patients and HVS. The incidence of RMS secondary to vancomycin or teicoplanin in our patient population appears to be low and consistent with clinical observations. Similar to previous investigations, RMS secondary to vancomycin in HVS was high (90%). However, we found no relationship between the histamine concentration in plasma or the area under the plasma histamine concentration-time curve and the severity of RMS in HVS. The reason for the discrepancy of RMS in patients versus that in HVS in unknown, but it may be related to a blunted effect of glycopeptides to produce the reaction in the presence of infection or it may be specific to our patient population.