Introduction: We investigated the role of colonization pressure on multiresistant Acinetobacter baumannii acquisition and defined patient-related predictors for carriage at admission and acquisition during hospitalization in intensive care unit (ICU) patients. Methods: This was a 12-month, prospective, cohort study of all patients admitted to a single ICU of a tertiary hospital. Screening samples were collected at ICU admission to identify imported carriers, and weekly during hospitalization to identify acquisition. Colonization pressure (carriers' patient-days × 100/all patients' patient-days) and the absolute number of carriers were calculated weekly, and the statistical correlation between these parameters and acquisition was explored. Multivariable analysis was performed to identify predictors for A. baumannii carriage at admission and acquisition during hospitalization. A. baumannii isolates were genotyped by repetitive-extragenic-palindromic polymerase chain reaction (PCR; rep-PCR). Results: At ICU admission, 284 patients were screened for carriage. A. baumannii was imported in 16 patients (5.6%), and acquisition occurred in 32 patients (15.7%). Acquisition was significantly correlated to weekly colonization pressure (correlation coefficient, 0.379; P = 0.004) and to the number of carriers per week (correlation coefficient, 0.499; P < 0.001). More than one carrier per week significantly increased acquisition risk (two to three carriers, odds ratio (OR), 12.66; P = 0.028; more than four carriers, OR, 25.33; P = 0.004). Predictors of carriage at admission were infection at admission (OR, 11.03; confidence interval (CI), 3.56 to 34.18; P < 0.01) and hospitalization days before ICU (OR, 1.09; CI, 1.01 to 1.16; P = 0.02). Predictors of acquisition were a medical reason for ICU admission (OR, 5.11; CI, 1.31 to 19.93; P = 0.02), duration of antibiotic administration in the unit (OR, 1.24; CI, 1.12 to 1.38; P < 0.001), and duration of mechanical ventilation (OR, 1.08; CI, 1.04 to 1.13; P = 0.001). All strains were multiresistant. Rep-PCR analysis showed one dominant cluster. Conclusions: Acquisition of multiresistant A. baumannii in ICU patients is strongly correlated to colonization pressure. High levels of colonization pressure and more than two carriers per week independently increase acquisition risk. Patient-related factors, such as infection at admission and long hospitalization before the ICU, can identify imported A. baumannii carriers. Medical patients with extended administration of antibiotics and long duration of mechanical ventilation in the ICU were the most vulnerable to acquisition.

Bacterial infections are frequent complications in cancer patients. Among them, those caused by multidrug-resistant (MDR) bacteria increase morbidity and mortality mainly because of limited therapeutic options. Current knowledge regarding MDR infections in patients with solid tumors is limited. We assessed the epidemiology and risk factors of increased mortality in these patients. In this retrospective five-year single cohort observational study, we included all oncological patients with MDR infections. Cancer-related parameters, comorbidities, prior use of antibiotics, previous surgical interventions and hospitalization, as well as the use of invasive procedures were investigated as potential risk factors causing adverse outcomes. Seventy-three patients with MDR infection were included: 37% with carbapenem-resistant Klebsiella pneumoniae, 24% with oxacillin-resistant Staphylococcus aureus (MRSA) and 21% with carbapenem-resistant Acinetobacter baumanni. Previous colonization with MDR bacteria was detected in 14% patients, while 20% of the patients presented MDR colonization or infection at ward admission. Mortality during the infection episode was 32%. Duration of hospitalization and CRP were statistically significant risk factors of mortality, whereas administration of guided antibiotics was a protective factor. Knowledge of local epidemiology of MDR bacteria can help physicians promptly identify cancer patients at risk of MDR infections and initiate timely effective empirical antibiotic treatment that can eventually improve the overall therapeutic management.

To evaluate silver-impregnated (Oligon) central venous catheters and chlorhexidine-gluconate-impregnated sponges for reducing catheter-related colonization and infection, nonbacteremic or bacteremic. Multicenter, prospective, randomized, controlled study. Five general intensive care units in Greece. Intensive care unit patients requiring a multilumen central venous catheter between June 2006 and May 2008. Patients were randomly assigned to receive a standard catheter (standard group), a standard catheter plus chlorhexidine-gluconate-impregnated sponge (chlorhexidine-gluconate-impregnated sponge group), or an Oligon catheter (Oligon group). Catheter colonization was defined as a positive quantitative tip culture (≥10 colony-forming units/mL), catheter-related infection was defined by the previous criterion plus clinical evidence of sepsis, and bacteremia catheter-related infection as catheter-related infection plus a positive peripheral blood culture with the same micro-organism as in the catheter tip. Data were obtained from 465 patients, 156 in the standard-group, 150 in the chlorhexidine-gluconate-impregnated sponge group, and 159 in the Oligon-group. Colonization occurred in 24 (15.4%) standard catheters, 21 (14%) in the chlorhexidine-gluconate-impregnated sponge group, and 25 (15.7%) in the Oligon catheters (p = .35) (20.9, 19.9, 21.8/1000 catheter-days, respectively). Catheter-related infections were recorded in nine (5.8%) standard catheters, six (4%) in the chlorhexidine-gluconate-impregnated sponge group, and seven (4.4%) in the Oligon catheters (p = .58) (7.8/1,000, 5.7/1,000, 6.1/1,000 catheter-days, respectively). No difference was observed between the chlorhexidine- gluconate-impregnated sponge group and the standard group regarding catheter colonization (hazard ratio 1.21; 95% confidence interval 0.56-2.61; p = .64) and catheter-related infections (hazard ratio 0.65; 95% confidence interval 0.23-1.85; p = .42). The Oligon catheter did not reduce colonization or catheter-related infections when compared with the standard catheter (colonization: hazard ratio 1.0; 95% confidence interval 0.46-2.21; p = .98; catheter-related infection: hazard ratio 0.72; 95% confidence interval 0.27-1.95; p = .52). Seven patients (1.5%, 2.09/1,000 catheter-days) presented bacteremic catheter-related infections. Central venous catheters inserted either in the internal jugular or the femoral vein had greater risk to be colonized than catheters inserted in the subclavian vein (internal jugular vs. subclavian: hazard ratio 3.29; 95% confidence interval 1.26-8.61; p = .01; femoral vs. subclavian: hazard ratio 3.36; 95% confidence interval 1.17-9.65; p = .02). Acinetobacter baumannii was the predominant pathogen (37.1% episodes of colonization, 36.4% catheter-related infections, 57.1% bacteremic catheter-related infections). For short-term (median duration 7 days) central venous catheters in intensive care units with high prevalence of multiresistant Gram-negative bacteria, chlorhexidine-impregnated sponges and Oligon catheters as single preventive measures did not reduce catheter colonization or catheter-related infections. As a result of the limited amount of events, no conclusion could be reached regarding bacteremic catheter-related infections. The femoral site was the most frequently colonized insertion site in all types of catheters.

Conventional diagnostic imaging is often ineffective in revealing the underlying cause in a considerable proportion of patients with fever of unknown origin (FUO). The aim of this study was to assess the diagnostic value of fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG-PET/CT) in patients with FUO. We retrospectively reviewed ¹⁸F-FDG-PET/CT scans performed on 50 consecutive adult patients referred to our department for further investigation of classic FUO. Final diagnosis was based on histopathological and microbiological findings, clinical criteria, or clinical follow-up. Final diagnosis was established in 39/50 (78%) of the patients. The cause of FUO was infection in 20/50 (40%), noninfectious inflammatory diseases in 11/50 (22%), and malignancy in 8/50 (16%) patients. Fever remained unexplained in 11/50 (22%) patients. ¹⁸F-FDG-PET/CT scan substantially contributed to the diagnosis in 70% of the patients, either by identifying the underlying cause of FUO or by directing to the most appropriate site for biopsy. Sensitivity, specificity, accuracy, positive predictive value (PPV) and negative predictive value (NPV) of ¹⁸F-FDG-PET/CT for active disease detection in patients with FUO were 94.7%, 50.0%, 84.0%, 85.7%, and 75.0%, respectively. In conclusion, whole-body ¹⁸F-FDG-PET/CT is a highly sensitive method for detection of the underlining cause of FUO or for correctly targeting suspicious lesions for further evaluation.

Ventilator-associated tracheobronchitis (VAT) is an infection commonly affecting mechanically ventilated intubated patients. Several studies suggest that VAT is associated with increased duration of mechanical ventilation (MV) and length of intensive care unit (ICU) stay, and a presumptive increase in healthcare costs. Uncertainties remain, however, regarding the cost/benefit balance of VAT treatment. The aim of this narrative review is to discuss the two fundamental and inter-related dilemmas regarding VAT, i.e., (i) how to diagnose VAT? and (ii) should we treat VAT? If yes, should we treat all cases or only selected ones? How should we treat in terms of antibiotic choice, route, treatment duration?

The intravenous (IV) formulation of fosfomycin has been re-introduced in clinical practice mainly to overcome treatment failures against multidrug-resistant (MDR) bacteria. Appropriate dosing schedules of the IV formulation have not yet been established. Areas covered: The mechanism of action and resistance development, commercial IV formulations, pharmacokinetic/pharmacodynamic (PK/PD) properties, IV dosing regimens for the treatment of MDR infections along with efficacy and safety issues were reviewed. Data regarding specific MDR pathogens, daily doses and patients' outcomes, gaps in the current literature, and in progress research agenda are presented. Expert opinion: The doses of fosfomycin IV range between 12 and 24 grams/day depending on the severity of infection. The efficacy and safety of the commonly administered doses have been shown mainly in observational non-comparative trials. The optimal dose ensuring maximal efficacy with minimal toxicity along with the most appropriate co-administered antibiotic(s) need further evaluation. The pharmacokinetic/pharmacodynamic parameter associated with maximum efficacy has not yet been established, although, the ratio of the area under the concentration-time curve (AUC) for the free unbound fraction of fosfomycin versus the MIC (fAUC/MIC) may be linked to optimal treatment. RCTs and other comparative studies are underway to address gaps of knowledge in adult patients and neonates.