In recent years, the worldwide spread of the so-called high-risk clones of multidrug-resistant or extensively drug-resistant (MDR/XDR) Pseudomonas aeruginosa has become a public health threat. This article reviews their mechanisms of resistance, epidemiology, and clinical impact and current and upcoming therapeutic options. In vitro and in vivo treatment studies and pharmacokinetic and pharmacodynamic (PK/PD) models are discussed.

Background. Several series predicting the prognosis of staphylococcal prosthetic joint infection (PJI) managed with debridement, antibiotics, and implant retention (DAIR) have been published, but some of their conclusions are controversial. At present, little is known regarding the efficacy of the different antibiotics that are used or their ability to eliminate methicillin-resistant S. aureus (MRSA) infection. Methods. This was a retrospective, multicenter, observational study of cases of PJI by S. aureus that were managed with DAIR (2003–2010). Cases were classified as failures when infection persistence/relapse, death, need for salvage therapy, or prosthesis removal occurred. The parameters that predicted failure were analyzed with logistic and Cox regression. Results. Out of 345 episodes (41% men, 73 years), 81 episodes were caused by MRSA. Fifty-two were hematogenous, with poorer prognoses, and 88% were caused by methicillin-susceptible S. aureus (MSSA). Antibiotics were used for a median of 93 days, with similar use of rifampin-based combinations in MSSA- and MRSA-PJI. Failure occurred in 45% of episodes, often early after debridement. The median survival time was 1257 days. There were no overall prognostic differences between MSSA- and MRSA-PJI, but there was a higher incidence of MRSA-PJI treatment failure during the period of treatment (HR 2.34), while there was a higher incidence of MSSA-PJI treatment failure after therapy. Rifampin-based combinations exhibited an independent protective effect. Other independent predictors of outcome were polymicrobial, inflammatory, and bacteremic infections requiring more than 1 debridement, immunosuppressive therapy, and the exchange of removable components of the prosthesis. Conclusions. This is the largest series of PJI by S. aureus managed with DAIR reported to date. The success rate was 55%. The use of rifampin may have contributed to homogenizing MSSA and MRSA prognoses, although the specific rifampin combinations may have had different efficacies.

Extended-spectrumβ-lactamase (ESBL)-producing Escherichia coli has emerged worldwide as a significant group of community pathogens.^1,2 This is of clinical importance because E coli is the most common cause of community-acquired urinary tract infections (UTIs), and ESBL-producing isolates are frequently resistant to many of the antimicrobial agents recommended for the treatment of such infections; this is particularly true of oral agents.³ While many studies have reported the microbiological characterization of community-acquired ESBL-producing E coli, published data that are clinically orientated are scarce; the few studies published concerning risk factors or the clinical significance of such infections involved only small samples of cases and were carried out in individual centers.^4-6 As the epidemiologic features of ESBL-producing organisms may show significant local variations, multicenter studies are particularly important to obtain comprehensive knowledge of risk factors for these infections. Likewise, studies that evaluate the efficacy of the few potentially useful oral drugs available for treatment are also needed.

To assess the association between inclusion of a macrolide in a β-lactam—based empirical antibiotic regimen and mortality among patients with bactere

Background. There is little clinical information about community-onset bloodstream infections (COBSIs) caused by extended-spectrum β-lactamase (ESBL)-p

Data regarding the most efficacious and least toxic schedules for the use of colistin are scarce. The aim of this study was to determine the incidence and the potential risk factors of colistin-associated nephrotoxicity including colistin plasma levels.