Tsioutis, Constantinos

Limited data exist regarding prognostic factors and optimal antimicrobial treatment of infections caused by extensively drug-resistant Acinetobacter baumannii (XDR-AB). This retrospective cohort study included 93 adult patients who developed ventilator-associated pneumonia (VAP) due to XDR-AB in the ICU of the University Hospital of Heraklion, Greece, from October 2012 to April 2015. XDR-AB isolates were mainly susceptible to colistin (93.5%) and tigecycline (25.8%), whereas 6 (6.5%) were pandrug-resistant. Prior to infection, patients had long durations of mechanical ventilation and hospital stay and multiple exposures to antibiotics. Median Charlson co-morbidity and APACHE II scores were 2 and 17, respectively. Mortality at 28 days of infection onset was high (34.4%) despite high rates of in-vitro-active empirical (81.7%) and definitive (90.3%) treatment. Active colistin-based combination therapy (n = 55) and monotherapy (n = 29) groups had similar 28-day mortality (27.6% vs. 30.9%, respectively) and Kaplan–Meier survival estimates over time. In multivariable Cox regression, advanced age (aHR = 1.05 per year increase, 95% CI 1.02–1.09), rapidly fatal underlying disease (aHR = 2.64, 95% CI 0.98–9.17) and APACHE II score (aHR = 1.06 per unit increase, 95% CI 0.99–1.14) were identified as independent predictors of 28-day mortality, but no difference in mortality hazards between the active colistin-based combination therapy and monotherapy groups was produced (aHR = 0.88, 95% CI 0.35–2.38). These results support the use of colistin as a first-line agent against VAP in settings where XDR-AB is endemic, but oppose the introduction of colistin-based combination therapy as standard treatment.

Background: In this first attempt to implement a standardized surveillance system of surgical site infections (SSI) in a Greek hospital, our objective was to identify areas for improvement by comparing main epidemiologic and microbiologic features of SSI with international data. Methods: The National Nosocomial Infections Surveillance (NNIS) system protocols were employed to prospectively collect data for patients in 8 surgical wards who underwent surgery during a 9-month period. SSI rates were benchmarked with international data using standardized infection ratios. Risk factors were evaluated by multivariate logistic regression. Results: A total of 129 SSI was identified in 2420 operations (5.3%), of which 47.3% developed after discharge. SSI rates were higher for 2 of 20 operation categories compared with Spanish and Italian data and for 12 of 20 categories compared with NNIS data. Gram-positive microorganisms accounted for 52.1% of SSI isolates, and Enterococci were predominant. Alarming resistance patterns for Enterococcus faecium and Acinetobacter baumannii were recorded. Potentially modifiable risk factors for SSI included multiple procedures, extended duration of operation, and antibiotic prophylaxis. SSI was associated with prolongation of postoperative stay but not with mortality. Conclusion: Comparisons of surveillance data in our hospital with international benchmarks provided useful information for infection control interventions to reduce the incidence of SSI.

Objectives: To identify the roles of various antibiotics as risk factors for carbapenem-resistant extendedspectrum β-lactamase (ESBL)-producing Klebsiella pneumoniae (KP) infection (ESBL-KP infection). Methods: Data were collected over 26 months in a tertiary care university hospital with established endemicity of carbapenem-resistant ESBL-KP (ESBL-CRKP). Using a case-case-control design, patients who presented an infection caused by carbapenem-susceptible ESBL-KP (ESBL-CSKP) and patients with ESBL-CRKP infection were compared with a common control group of hospitalized patients. Effects of treatment and duration of treatment with antibiotics were examined, adjusting for major non-antibiotic risk factors and controlling for confounding effects among the antibiotics via logistic regression models. Results: Ninety-six ESBL-CRKP cases, 55 ESBL-CSKP cases and 151 controls were analysed. Multivariate analysis, adjusting for major non-antibiotic risk factors, showed that the risk of ESBL-CRKP infection rose with increasing duration of prior treatment with β-lactam/β-lactamase inhibitor combinations [odds ratio (OR) 1.15 per day increase; P=0.001] and revealed that increased duration of treatment with fluoroquinolones amplified the impact of exposure to carbapenems (and vice versa) on ESBL-CRKP infection risk (OR 1.02 for interaction term; P=0.009). Duration of prior treatment with fluoroquinolones was also associated with increased risk of ESBL-CSKP infection (OR 1.07 per day increase; P=0.028), while prior receipt of carbapenems presented a protective effect against ESBL-CSKP infection (OR 0.21; P=0.003). Conclusions: This study highlights the major role of treatment and duration of treatment with b-lactam/blactamase inhibitor combinations and combinations of carbapenems with fluoroquinolones. Clinicians should counterweight the potential benefits of administering these antibiotics against the increased risk of ESBLCRKP infection.

Clinical reports on infections by pandrugresistant (PDR) bacteria are scarce. This observational case series study was conducted during a 2-year period at a university hospital. Patients infected by PDR gram-negative bacteria comprised the study cohort. An isolate was defined as PDR if it was resistant to all antibiotic classes available for empirical treatment. A total of 21 patients infected by PDR gram-negative bacteria were recorded. The mean APACHE II score on admission was 18.8, the mean Charlson comorbidity index was 2.9, and 20 (95.2%) patients had a history of intensive care unit hospitalization. All patients had recent exposure to multiple antibiotics (median, 6 antibiotic groups). Infections occurred at a mean of 41.5 days after admission. The mean length of stay after infection was 54.6 days and 5 (23.8%) patients died due to the infection. Treatment was mainly based on a colistincontaining regimen (47.6%) or tigecycline (33.3%). All patients treated with tigecycline had total resolution of the infection and a notably shorter length of hospital stay after infection. In conclusion, PDR gram-negative bacterial infections are associated with considerable prolongation of hospitalization and mortality, although the mortality is not as high as that expected. Tigecycline appears to be effective for the successful treatment of PDR infections