Ceftazidime-avibactam (CAZ-AVI) has been approved in Europe for the treatment of complicated intra-abdominal and urinary tract infections, as well as hospital-acquired pneumonia, and for gram-negative infections with limited treatment options. CAZ-AVI displays in vitro activity against Klebsiella pneumoniae carbapenemase (KPC) enzyme producers, but clinical trial data on its efficacy in this setting are lacking. We retrospectively reviewed 138 cases of infections caused by KPC-producing K. pneumoniae (KPC-Kp) in adults who received CAZ-AVI in compassionate-use programs in Italy. Case features and outcomes were analyzed, and survival was then specifically explored in the large subcohort whose infections were bacteremic. The 138 patients started CAZ-AVI salvage therapy after a first-line treatment (median, 7 days) with other antimicrobials. CAZ-AVI was administered with at least 1 other active antibiotic in 109 (78.9%) cases. Thirty days after infection onset, 47 (34.1%) of the 138 patients had died. Thirty-day mortality among the 104 patients with bacteremic KPC-Kp infections was significantly lower than that of a matched cohort whose KPC-Kp bacteremia had been treated with drugs other than CAZ-AVI (36.5% vs 55.8%, P = .005). Multivariate analysis of the 208 cases of KPC-Kp bacteremia identified septic shock, neutropenia, Charlson comorbidity index ≥3, and recent mechanical ventilation as independent predictors of mortality, whereas receipt of CAZ-AVI was the sole independent predictor of survival. CAZ-AVI appears to be a promising drug for treatment of severe KPC-Kp infections, especially those involving bacteremia.

A growing body of observational evidence supports the value of ceftazidime-avibactam (CAZ-AVI) in managing infections caused by carbapenem-resistant Enterobacteriaceae. We retrospectively analyzed observational data on use and outcomes of CAZ-AVI therapy for infections caused by Klebsiella pneumoniae carbapenemase–producing K. pneumoniae (KPC-Kp) strains. Multivariate regression analysis was used to identify variables independently associated with 30-day mortality. Results were adjusted for propensity score for receipt of CAZ-AVI combination regimens versus CAZ-AVI monotherapy. The cohort comprised 577 adults with bloodstream infections (n = 391) or nonbacteremic infections involving mainly the urinary tract, lower respiratory tract, and intra-abdominal structures. All received treatment with CAZ-AVI alone (n = 165) or with ≥1 other active antimicrobials (n = 412). The all-cause mortality rate 30 days after infection onset was 25% (146/577). There was no significant difference in mortality between patients managed with CAZ-AVI alone and those treated with combination regimens (26.1% vs 25.0%, P = .79). In multivariate analysis, mortality was positively associated with presence at infection onset of septic shock (P = .002), neutropenia (P < .001), or an INCREMENT score ≥8 (P = .01); with lower respiratory tract infection (LRTI) (P = .04); and with CAZ-AVI dose adjustment for renal function (P = .01). Mortality was negatively associated with CAZ-AVI administration by prolonged infusion (P = .006). All associations remained significant after propensity score adjustment. CAZ-AVI is an important option for treating serious KPC-Kp infections, even when used alone. Further study is needed to explore the drug’s seemingly more limited efficacy in LRTIs and potential survival benefits of prolonging CAZ-AVI infusions to ≥3 hours.

Background Prolonged mechanical ventilation (PMV) after heart surgery is associated with increased patient morbidity and mortality. Methods In this prospective observational cohort study the aim was to assess PMV predictors and its impact on ICU, hospital length of stay and survival in cardiac surgical patients admitted to our eight-bed ICU from January 2000 to December 2006. All perioperative patient variables were put into an electronic database. Five thousand one hundred and twenty-three patients were divided into two cohorts: early extubation, undergoing a successful extubation for 12 h or less, and delayed extubation, needing a mechanical ventilation for more than 12 h. Results A logistic regression model identified the following as PMV predictors: age more than 65 years [odds ratio (OR), 1.296; 95% confidence interval (CI), 1.017–1.069; P = 0.016], chronic renal failure (OR, 1.571; 95% CI, 1.566–2.466; P = 0.011), chronic obstructive pulmonary disease (OR, 1.453; 95% CI, 1.695–2.454; P = 0.006), redo surgery (OR, 2.010; 95% CI, 1.389– 2.114; P = 0.001), emergency surgery (OR, 1.622; 95% CI, 1.515–2.494; P = 0.016), New York Heart Association/Canadian Cardiovascular Society class higher than 2 (OR, 1.491; 95% CI, 1.704–2.321; P = 0.001), left ventricular ejection fraction of 30% or less (OR, 2.125; 95% CI, 1.379–1.991; P = 0.000), red blood cell (OR, 5.430; 95% CI, 3.636–8.130; P = 0.000) and fresh frozen plasma transfusion units more than four (OR, 3.019; 95% CI, 1.808–5.050; P = 0.000) and cardiopulmonary bypass time more than 77 min (OR, 2.030; 95% CI, 1.248–2.174; P = 0.002). Early extubation group patients showed a higher probability of being discharged from ICU to cardiac surgical ward (log-rank = 1108.951; P = 0.000) and from cardiac to rehabilitation ward (log-rank = 598.005; P = 0.000) and higher hospital survival (log-rank = 53.215; P = 0.000). Conclusion This review allowed us to assess predictors, helping us to identify ‘a priori’ patients more likely to undergo PMV.

The challenging severity of some infections, especially in critically ill patients, makes the diffusion of antimicrobial drugs within tissues one of the cornerstones of chemotherapy. The knowledge of how antibacterial agents penetrate tissues may come from different sources: preclinical studies in animal models, phase I–III clinical trials and post-registration studies. However, the particular physiopathology of critically ill patients may significantly alter drug pharmacokinetics. Indeed, changes in interstitial volumes (the third space) and/or in glomerular filtration ratio may influence the achievement of bactericidal concentrations in peripheral compartments, while inflammation can alter the systemic distribution of some drugs. On the contrary, other antibacterial agents may reach high and effective concentrations thanks to the increased tissue accumulation of macrophages and neutrophils. Therefore, the present review explores the tissue distribution of beta-lactams and other antimicrobials acting on the cell wall and cytoplasmic membrane of bacteria in critically ill patients. A systematic search of articles was performed according to PRISMA guidelines, and tissue/plasma penetration ratios were collected. Results showed a highly variable passage of drugs within tissues, while large interindividual variability may represent a hurdle which must be overcome to achieve therapeutic concentrations in some compartments. To solve that issue, off-label dosing regimens could represent an effective solution in particular conditions.

In patients that are admitted to intensive care units (ICUs), the clinical outcome of severe infections depends on several factors, as well as the early administration of chemotherapies and comorbidities. Antimicrobials may be used in off-label regimens to maximize the probability of therapeutic concentrations within infected tissues and to prevent the selection of resistant clones. Interestingly, the literature clearly shows that the rate of tissue penetration is variable among antibacterial drugs, and the correlation between plasma and tissue concentrations may be inconstant. The present review harvests data about tissue penetration of antibacterial drugs in ICU patients, limiting the search to those drugs that mainly act as protein synthesis inhibitors and disrupting DNA structure and function. As expected, fluoroquinolones, macrolides, linezolid, and tigecycline have an excellent diffusion into epithelial lining fluid. That high penetration is fundamental for the therapy of ventilator and healthcare-associated pneumonia. Some drugs also display a high penetration rate within cerebrospinal fluid, while other agents diffuse into the skin and soft tissues. Further studies are needed to improve our knowledge about drug tissue penetration, especially in the presence of factors that may affect drug pharmacokinetics.

Introduction: Not enough data exist to inform the optimal duration and type of antimicrobial therapy against GN infections in critically ill patients. Methods: Narrative review based on a literature search through PubMed and Cochrane using the following keywords: “multi-drug resistant (MDR)”, “extensively drug resistant (XDR)”, “pan-drug-resistant (PDR)”, “difficult-to-treat (DTR) Gram-negative infection,” “antibiotic duration therapy”, “antibiotic combination therapy” “antibiotic monotherapy” “Gram-negative bacteremia”, “Gram-negative pneumonia”, and “Gram-negative intra-abdominal infection”. Results: Current literature data suggest adopting longer (≥10–14 days) courses of synergistic combination therapy due to the high global prevalence of ESBL-producing (45–50%), MDR (35%), XDR (15–20%), PDR (5.9–6.2%), and carbapenemases (CP)/metallo-β-lactamases (MBL)-producing (12.5–20%) Gram-negative (GN) microorganisms (i.e., Klebsiella pneumoniae, Pseudomonas aeruginosa, and Acinetobacter baumanii). On the other hand, shorter courses (≤5–7 days) of monotherapy should be limited to treating infections caused by GN with higher (≥3 antibiotic classes) antibiotic susceptibility. A general approach should be based on (i) third or further generation cephalosporins ± quinolones/aminoglycosides in the case of MDR-GN; (ii) carbapenems ± fosfomycin/aminoglycosides for extended-spectrum β-lactamases (ESBLs); and (iii) the association of old drugs with new expanded-spectrum β-lactamase inhibitors for XDR, PDR, and CP microorganisms. Therapeutic drug monitoring (TDM) in combination with minimum inhibitory concentration (MIC), bactericidal vs. bacteriostatic antibiotics, and the presence of resistance risk predictors (linked to patient, antibiotic, and microorganism) should represent variables affecting the antimicrobial strategies for treating GN infections. Conclusions: Despite the strategies of therapy described in the results, clinicians must remember that all treatment decisions are dynamic, requiring frequent reassessments depending on both the clinical and microbiological responses of the patient.