Medline ® Abstracts for References 60-63
of 'Treatment of community-acquired pneumonia in adults who require hospitalization'
Generic vancomycin products fail in vivo despite being pharmaceutical equivalents of the innovator.
Vesga O, Agudelo M, Salazar BE, Rodriguez CA, Zuluaga AF
Antimicrob Agents Chemother. 2010;54(8):3271.
Generic versions of intravenous antibiotics are not required to demonstrate therapeutic equivalence with the innovator because therapeutic equivalence is assumed from pharmaceutical equivalence. To test such assumptions, we studied three generic versions of vancomycin in simultaneous experiments with the innovator and determined the concentration and potency of the active pharmaceutical ingredient by microbiological assay, single-dose pharmacokinetics in infected mice, antibacterial effect by broth microdilution and time-kill curves (TKC), and pharmacodynamics against two wild-type strains of Staphylococcus aureus by using the neutropenic mouse thigh infection model. The main outcome measure was the comparison of magnitudes and patterns of in vivo efficacy between generic products and the innovator. Except for one product exhibiting slightly greater concentration, vancomycin generics were undistinguishable from the innovator based on concentration and potency, protein binding, in vitro antibacterial effect determined by minimal inhibitory or bactericidal concentrations and TKC, and serum pharmacokinetics. Despite such similarities, all generic products failed in vivo to kill S. aureus, while the innovator displayed the expected bactericidal efficacy: maximum antibacterial effect (Emax) (95% confidence interval [CI]) was 2.04 (1.89 to 2.19), 2.59 (2.21 to 2.98), and 3.48 (2.92 to 4.04) versus 5.65 (5.52 to 5.78) log10 CFU/g for three generics and the innovator product, respectively (P<0.0001, any comparison). Nonlinear regression analysis suggests that generic versions of vancomycin contain inhibitory and stimulatory principles within their formulations that cause agonistic-antagonistic actions responsible for in vivo failure. In conclusion, pharmaceutical equivalence does not imply therapeutic equivalence for vancomycin.
GRIPE (Grupo Investigador de Problemas en Enfermedades Infecciosas), Calle 62 No. 52-59, Lab. 630, SIU, UdeA, Medellín, Colombia. email@example.com
Staphylococcus aureus community-acquired pneumonia during the 2006 to 2007 influenza season.
Kallen AJ, Brunkard J, Moore Z, Budge P, Arnold KE, Fosheim G, Finelli L, Beekmann SE, Polgreen PM, Gorwitz R, Hageman J
Ann Emerg Med. 2009;53(3):358.
STUDY OBJECTIVE: Staphylococcus aureus is a cause of community-acquired pneumonia that can follow influenza infection. In response to a number of cases reported to public health authorities in early 2007, additional case reports were solicited nationwide to better define S. aureus community-acquired pneumonia during the 2006 to 2007 influenza season.
METHODS: Cases were defined as primary community-acquired pneumonia caused by S. aureus occurring between November 1, 2006, and April 30, 2007. Case finding was conducted through an Emerging Infections Network survey and through contacts with state and local health departments.
RESULTS: Overall, 51 cases were reported from 19 states; 37 (79%) of 47 with known susceptibilities involved infection with methicillin-resistant S. aureus (MRSA). The median age of case patients was 16 years, and 44% had no known pertinent medical history. Twenty-two (47%) of 47 case patients with information about other illnesses were diagnosed with a concurrent or antecedent viral infection during their illness, and 11 of 33 (33%) who were tested had laboratory-confirmed influenza. Of the 37 patients with MRSA infection, 16 (43%) were empirically treated with antimicrobial agents recommended for MRSA community-acquired pneumonia. Twenty-four (51%) of 47 patients for whom final disposition was known died a median of 4 days after symptom onset.
CONCLUSION: S. aureus continues to cause community-acquired pneumonia, with most reported cases caused by MRSA and many occurring with or after influenza. In this series, patients were often otherwise healthy young people and mortality rates were high. Further prospective investigation is warranted to clarify infection incidence, risk factors, and preventive measures.
Division of Healthcare Quality Promotion, National Center for Preparedness, Detection and Control of Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA. AKallen@cdc.gov
Combination antibiotic therapy improves survival in patients with community-acquired pneumonia and shock.
Rodríguez A, Mendia A, Sirvent JM, Barcenilla F, de la Torre-Prados MV, Solé-Violán J, Rello J, CAPUCI Study Group
Crit Care Med. 2007;35(6):1493.
OBJECTIVE: To assess whether combination antibiotic therapy improves outcome of severe community-acquired pneumonia in the subset of patients with shock.
DESIGN: Secondary analysis of a prospective observational, cohort study.
SETTING: Thirty-three intensive care units (ICUs) in Spain.
PATIENTS: Patients were 529 adults with community-acquired pneumonia requiring ICU admission.
MEASUREMENT AND MAIN RESULTS: Two hundred and seventy (51%) patients required vasoactive drugs and were categorized as having shock. The effects of combination antibiotic therapy and monotherapy on survival were compared using univariate analysis and a Cox regression model. The adjusted 28-day in-ICU mortality was similar (p = .99) for combination antibiotic therapy and monotherapy in the absence of shock. However, in patients with shock, combination antibiotic therapy was associated with significantly higher adjusted 28-day in-ICU survival (hazard ratio, 1.69; 95% confidence interval, 1.09-2.60; p = .01) in a Cox hazard regression model. Even when monotherapy was appropriate, it achieved a lower 28-day in-ICU survival than an adequate antibiotic combination (hazard ratio, 1.64; 95% confidence interval, 1.01-2.64).
CONCLUSIONS: Combination antibiotic therapy does not seem to increase ICU survival in all patients with severe community-acquired pneumonia. However, in the subset of patients with shock, combination antibiotic therapy improves survival rates.
Intensive Care Unit, Joan XXIII University Hospital, Tarragona, Spain.
Addition of a macrolide to a beta-lactam-based empirical antibiotic regimen is associated with lower in-hospital mortality for patients with bacteremic pneumococcal pneumonia.
Martínez JA, Horcajada JP, Almela M, Marco F, Soriano A, García E, Marco MA, Torres A, Mensa J
Clin Infect Dis. 2003;36(4):389.
To assess the association between inclusion of a macrolide in a beta-lactam-based empirical antibiotic regimen and mortality among patients with bacteremic pneumococcal pneumonia, 10 years of data from a database were analyzed. The total available set of putative prognostic factors was subjected to stepwise logistic regression, with in-hospital death as the dependent variable. Of the 409 patients analyzed, 238 (58%) received a beta-lactam plus a macrolide and 171 (42%) received a beta-lactam without a macrolide. Multivariate analysis revealed 4 variables to be independently associated with death: shock (P<.0001), age of>or=65 years (P=.02), infections with pathogens that have resistance to both penicillin and erythromycin (P=.04), and no inclusion of a macrolide in the initial antibiotic regimen (P=.03). For patients with bacteremic pneumococcal pneumonia, not adding a macrolide to a beta-lactam-based initial antibiotic regimen is an independent predictor of in-hospital mortality. However, only a randomized study can definitively determine whether this association is due to a real effect of macrolides.
Institut Clínic Infeccions i Immunologia, Hospital Clinic Universitari, Barcelona, Spain. firstname.lastname@example.org