Michele Bartoletti

Infections caused by KPC-producing Klebsiella pneumoniae: differences in therapy and mortality in a multicentre study

OBJECTIVES Infections caused by Klebsiella pneumoniae (Kp) carbapenemase (KPC)-producing strains of Kp have become a significant threat in recent years. To assess their outcomes and identify risk factors for 14 day mortality, we conducted a 4 year (2010-13) retrospective cohort study in five large Italian teaching hospitals. METHODS The cohort included 661 adults with bloodstream infections (BSIs; n = 447) or non-bacteraemic infections (lower respiratory tract, intra-abdominal structure, urinary tract or other sites) caused by a KPC-Kp isolate. All had received ≥48 h of therapy (empirical and/or non-empirical) with at least one drug to which the isolate was susceptible. RESULTS Most deaths occurred within 2 weeks of infection onset (14 day mortality: 225/661, 34.1%). Logistic regression analysis identified BSI (OR, 2.09; 95% CI, 1.34-3.29), presentation with septic shock (OR, 2.45; 95% CI, 1.47-4.08), inadequate empirical antimicrobial therapy (OR, 1.48; 95% CI, 1.01-2.18), chronic renal failure (OR, 2.27; 95% CI, 1.44-3.58), high APACHE III score (OR, 1.05; 95% CI, 1.04-1.07) and colistin-resistant isolates (OR, 2.18; 95% CI, 1.37-3.46) as independent predictors of 14 day mortality. Combination therapy with at least two drugs displaying in vitro activity against the isolate was associated with lower mortality (OR, 0.52; 95% CI, 0.35-0.77), in particular in patients with BSIs, lung infections or high APACHE III scores and/or septic shock at infection onset. Combinations that included meropenem were associated with significantly higher survival rates when the KPC-Kp isolate had a meropenem MIC of ≤8 mg/L. CONCLUSIONS KPC-Kp infections are associated with high mortality. Treatment with two or more drugs displaying activity against the isolate improves survival, mainly in patients who are critically ill.

Effect of appropriate combination therapy on mortality of patients with bloodstream infections due to carbapenemase-producing Enterobacteriaceae (INCREMENT): a retrospective cohort study

BACKGROUND The best available treatment against carbapenemase-producing Enterobacteriaceae (CPE) is unknown. The objective of this study was to investigate the effect of appropriate therapy and of appropriate combination therapy on mortality of patients with bloodstream infections (BSIs) due to CPE. METHODS In this retrospective cohort study, we included patients with clinically significant monomicrobial BSIs due to CPE from the INCREMENT cohort, recruited from 26 tertiary hospitals in ten countries. Exclusion criteria were missing key data, death sooner than 24 h after the index date, therapy with an active antibiotic for at least 2 days when blood cultures were taken, and subsequent episodes in the same patient. We compared 30 day all-cause mortality between patients receiving appropriate (including an active drug against the blood isolate and started in the first 5 days after infection) or inappropriate therapy, and for patients receiving appropriate therapy, between those receiving active monotherapy (only one active drug) or combination therapy (more than one). We used a propensity score for receiving combination therapy and a validated mortality score (INCREMENT-CPE mortality score) to control for confounders in Cox regression analyses. We stratified analyses of combination therapy according to INCREMENT-CPE mortality score (0-7 [low mortality score] vs 8-15 [high mortality score]). INCREMENT is registered with ClinicalTrials.gov, number NCT01764490. FINDINGS Between Jan 1, 2004, and Dec 31, 2013, 480 patients with BSIs due to CPE were enrolled in the INCREMENT cohort, of whom we included 437 (91%) in this study. 343 (78%) patients received appropriate therapy compared with 94 (22%) who received inappropriate therapy. The most frequent organism was Klebsiella pneumoniae (375 [86%] of 437; 291 [85%] of 343 patients receiving appropriate therapy vs 84 [89%] of 94 receiving inappropriate therapy) and the most frequent carbapenemase was K pneumoniae carbapenemase (329 [75%]; 253 [74%] vs 76 [81%]). Appropriate therapy was associated with lower mortality than was inappropriate therapy (132 [38·5%] of 343 patients died vs 57 [60·6%] of 94; absolute difference 22·1% [95% CI 11·0-33·3]; adjusted hazard ratio [HR] 0·45 [95% CI 0·33-0·62]; p<0·0001). Among those receiving appropriate therapy, 135 (39%) received combination therapy and 208 (61%) received monotherapy. Overall mortality was not different between those receiving combination therapy or monotherapy (47 [35%] of 135 vs 85 [41%] of 208; adjusted HR 1·63 [95% CI 0·67-3·91]; p=0·28). However, combination therapy was associated with lower mortality than was monotherapy in the high-mortality-score stratum (30 [48%] of 63 vs 64 [62%] of 103; adjusted HR 0·56 [0·34-0·91]; p=0·02), but not in the low-mortality-score stratum (17 [24%] of 72 vs 21 [20%] of 105; adjusted odds ratio 1·21 [0·56-2·56]; p=0·62). INTERPRETATION Appropriate therapy was associated with a protective effect on mortality among patients with BSIs due to CPE. Combination therapy was associated with improved survival only in patients with a high mortality score. Patients with BSIs due to CPE should receive active therapy as soon as they are diagnosed, and monotherapy should be considered for those in the low-mortality-score stratum. FUNDING Spanish Network for Research in Infectious Diseases, European Development Regional Fund, Instituto de Salud Carlos III, and Innovative Medicines Initiative.

Klebsiella pneumoniae bloodstream infection: epidemiology and impact of inappropriate empirical therapy.

AbstractMultidrug resistance associated with extended-spectrum beta-lactamase (ESBL) and Klebsiella pneumoniae carbapenemase (KPC) among K. pneumoniae is endemic in southern Europe. We retrospectively analyzed the impact of resistance on the appropriateness of empirical therapy and treatment outcomes of K. pneumoniae bloodstream infections (BSIs) during a 2-year period at a 1420-bed tertiary-care teaching hospital in northern Italy. We identified 217 unique patient BSIs, including 92 (42%) KPC-positive, 49 (23%) ESBL-positive, and 1 (0.5%) metallo-beta-lactamase-positive isolates. Adequate empirical therapy was administered in 74% of infections caused by non-ESBL non-KPC strains, versus 33% of ESBL and 23% of KPC cases (p < 0.0001). To clarify the impact of resistance on BSI treatment outcomes, we compared several different models comprised of non-antibiotic treatment-related factors predictive of patients’ 30-day survival status. Acute Physiology and Chronic Health Evaluation (APACHE) II score determined at the time of positive blood culture was superior to other investigated models, correctly predicting survival status in 83% of the study cohort. In multivariate analysis accounting for APACHE II, receipt of inadequate empirical therapy was associated with nearly a twofold higher rate of death (adjusted hazard ratio 1.9, 95% confidence interval 1.1–3.4; p = 0.02). Multidrug-resistant K. pneumoniae accounted for two-thirds of all K. pneumoniae BSIs, high rates of inappropriate empirical therapy, and twofold higher rates of patient death irrespective of underlying illness.

Epidemiology and outcomes of bloodstream infection in patients with cirrhosis

BACKGROUND & AIMS Bloodstream infections (BSIs) in cirrhotic patients are 10-fold more common than in non-cirrhotic patients and increasingly caused by resistant pathogens. We examined 162 BSI episodes in cirrhotic patients to describe the etiology and risk factors for 30-day mortality. METHODS We retrospectively analyzed all consecutive BSIs in patients with liver cirrhosis at our 1350-bed teaching hospital (January 2008 to June 2012). Cox-proportional hazard regression was used to analyze the impact of disease and treatment-related variables on the crude 30-day mortality. RESULTS BSI episodes were identified in 162 patients, including 29 mixed infections. Most of episodes were classified as hospital acquired or healthcare associated (93%). Gram-negative bacteria (GNB), Gram-positive bacteria and Candida spp. caused 64%, 38%, and 10% of episodes, respectively. GNB were classified as multi-drug resistant (MDR) and extensively drug resistant (XDR) in 25% and 21% of cases, respectively. The overall crude 30-day mortality rate was 29%. Four risk factors were independently associated with 30-day crude mortality: worsening of MELD score from baseline (the last MELD score available in the 2 weeks prior BSI) to that at BSI onset (HR 1.11 per point increase, 95% CI 1.07-1.15, p<0.0001), spontaneous bacterial peritonitis as BSI source (HR 4.42, 2.04-9.54, p=0.002), sepsis grading (HR 2.18, 1.39-3.43, p=0.0007), and inappropriate antibiotic therapy within 24h from blood cultures (HR 2.82, 1.50-5.41, p=0.002). CONCLUSION An increasing proportion of BSIs in cirrhotic patients are caused by resistant GNB and Candida spp. Accurate evaluation of risk factors for mortality may improve early appropriate therapeutic management.

Predictive Models for Identification of Hospitalized Patients Harboring KPC-Producing Klebsiella pneumoniae

ABSTRACT The production of Klebsiella pneumoniae carbapenemases (KPCs) by Enterobacteriaceae has become a significant problem in recent years. To identify factors that could predict isolation of KPC-producing K. pneumoniae (KPCKP) in clinical samples from hospitalized patients, we conducted a retrospective, matched (1:2) case-control study in five large Italian hospitals. The case cohort consisted of adult inpatients whose hospital stay included at least one documented isolation of a KPCKP strain from a clinical specimen. For each case enrolled, we randomly selected two matched controls with no KPCKP-positive cultures of any type during their hospitalization. Matching involved hospital, ward, and month/year of admission, as well as time at risk for KPCKP isolation. A subgroup analysis was also carried out to identify risk factors specifically associated with true KPCKP infection. During the study period, KPCKP was isolated from clinical samples of 657 patients; 426 of these cases appeared to be true infections. Independent predictors of KPCKP isolation were recent admission to an intensive care unit (ICU), indwelling urinary catheter, central venous catheter (CVC), and/or surgical drain, ≥2 recent hospitalizations, hematological cancer, and recent fluoroquinolone and/or carbapenem therapy. A Charlson index of ≥3, indwelling CVC, recent surgery, neutropenia, ≥2 recent hospitalizations, and recent fluoroquinolone and/or carbapenem therapy were independent risk factors for KPCKP infection. Models developed to predict KPCKP isolation and KPCKP infection displayed good predictive power, with the areas under the receiver-operating characteristic curves of 0.82 (95% confidence interval [CI], 0.80 to 0.84) and 0.82 (95% CI, 0.80 to 0.85), respectively. This study provides novel information which might be useful for the clinical management of patients harboring KPCKP and for controlling the spread of this organism.

Statin therapy decreases serum levels of high-sensitivity C-reactive protein and tumor necrosis factor-α in HIV-infected patients treated with ritonavir-boosted protease inhibitors.

Abstract Background: Statins are lipid-lowering drugs that exhibit anti-inflammatory and immune-modulatory properties, leading to a reduction of serum levels of C-reactive protein (CRP) in the general population. Objective: Because very limited data are available today, our objective was to assess the lipid-lowering effects of statins and their capacity to decrease selected soluble markers of inflammation in HIV-infected patients. Methods: Retrospective cohort study of HIV-infected adult patients with hypercholesterolemia who were receiving a stable antiretroviral regimen including a ritonavir-boosted protease inhibitor and who started a lipid-lowering therapy with rosuvastatin (10 mg daily), atorvastatin (10 mg daily), or pravastatin (40 mg daily) and were followed-up for at least 12 months. One hundred and fifty-one patients were enrolled in the study: 51 in the rosuvastatin group, 47 in the atorvastatin group, and 53 in the pravastatin group. The primary observation was change in plasma lipid levels and serum markers of inflammation (high-sensitivity C-reactive protein [hsCRP], interleukin-6 [IL-6], and tumor necrosis factor-α [TNF- α]), while secondary observations include immunovirological parameters and safety profile of statins. Results: One year after starting the statin therapy, patients treated with rosuvastatin had significantly greater decreases in total cholesterol and LDL cholesterol than subjects on atorvastatin or pravastatin. All statins led to a similar, significant reduction in serum levels of hsCRP and TNF-α, without correlation between biomarkers and lipid values, and toxicity rates were similar for all 3 statins. Conclusion: Our findings suggest that rosuvastatin has a significantly greater lipid-lowering effect than atorvastatin or pravastatin, but all 3 statins exert a similar effect in lowering markers of inflammation as hsCRP and TNF-α.

Impact of a hospital-wide multifaceted programme for reducing carbapenem-resistant Enterobacteriaceae infections in a large teaching hospital in northern Italy.

We performed a quasi-experimental study of a multifaceted infection control programme for reducing carbapenem-resistant Enterobacteriaceae (CRE) transmission and bloodstream infections (BSIs) in a 1420-bed university-affiliated teaching hospital during 2010-2014, with 30 months of follow-up. The programme consisted of the following: (a) rectal swab cultures were performed in all patients admitted to high-risk units (intensive-care units, transplantation, and haematology) to screen for CRE carriage, or for any room-mates of CRE-positive patients in other units; (b) cohorting of carriers, managed with strict contact precautions; (c) intensification of education, cleaning and hand-washing programmes; and (d) promotion of an antibiotic stewardship programme carbapenem-sparing regimen. The 30-month incidence rates of CRE-positive rectal cultures and BSIs were analysed with Poisson regression. Following the intervention, the incidence rate of CRE BSI (risk reduction 0.96, 95% CI 0.92-0.99, p 0.03) and CRE colonization (risk reduction 0.96, 95% CI 0.95-0.97, p <0.0001) significantly decreased over a period of 30 months. After accounting for changes in monthly census and percentage of externally acquired cases (positive at ≤72 h), the average institutional monthly rate of compliance with CRE screening procedures was the only independent variable associated with a declining monthly incidence of CRE colonization (p 0.002). The monthly incidence of CRE carriage was predictive of BSI (p 0.01). Targeted screening and cohorting of CRE carriers and infections, combined with cleaning, education, and antimicrobial stewardship measures, significantly decreased the institutional incidence of CRE BSI and colonization, despite endemically high CRE carriage rates in the region.

Risk Factors for Infection With Carbapenem‐Resistant Klebsiella pneumoniae After Liver Transplantation: The Importance of Pre‐ and Posttransplant Colonization

Improved understanding of risk factors associated with carbapenem‐resistant‐Klebsiella pneumoniae (CR‐KP) infection after liver transplantation (LT) can aid development of effective preventive strategies. We performed a prospective cohort study of all adult patients undergoing LT at our hospital during 30‐month period to define risk factors associated with CR‐KP infection. All patients were screened for CR‐KP carriage by rectal swabs before and after LT. No therapy was administered to decolonize or treat asymptomatic CR‐KP carriers. All patients were monitored up to 180 days after LT. Of 237 transplant patients screened, 41 were identified as CR‐KP carriers (11 at LT, 30 after LT), and 20 developed CR‐KP infection (18 bloodstream‐infection, 2 pneumonia) a median of 41.5 days after LT. CR‐KP infection rates among patients non‐colonized, colonized at LT, and colonized after LT were 2%, 18.2% and 46.7% (p < 0.001). Independent risk factors for CR‐KP infection identified by multivariate analysis, included: renal‐replacement‐therapy; mechanical ventilation > 48 h; HCV recurrence, and colonization at any time with CR‐KP. Based on these four variables, we developed a risk score that effectively discriminated patients at low versus higher risk for CR‐KP infection (AUC 0.93, 95% CI 0.86–1.00, p < 0.001). Our results may help to design preventive strategies for LT recipients in CR‐KP endemic areas.

Combined computed tomography and fluorodeoxyglucose positron emission tomography in the diagnosis of prosthetic valve endocarditis: a case series.

BackgroundThe diagnosis of prosthetic valve endocarditis is challenging. The gold standard for prosthetic valve endocarditis diagnosis is trans-esophageal echocardiography. However, trans-esophageal echocardiography may result in negative findings or yield images difficult to differentiate from thrombus in patients with prosthetic valve endocarditis. Combined computed tomography and fluorodeoxyglucose positron emission tomography is a potentially promising diagnostic tool for several infectious conditions and it has also been employed in patients with prosthetic valve endocarditis but data are still scant.Case presentationsWe reviewed the charts of 6 patients with prosthetic aortic valves evaluated for suspicion of prosthetic valve endocarditis, at two different hospital, over a 3-year period. We found 3 patients with early-onset PVE cases and blood cultures yielding Pseudomonas aeruginosa, Staphylococcus epidermidis and Staphylococcus lugdunensis, respectively; and 3 late-onset cases in the remaining 3 patients with isolation in the blood of Streptococcus bovis, Candida albicans and P. aeruginosa, respectively. Initial trans-esophageal echocardiography was negative in all the patients, while fluorodeoxyglucose positron emission tomography showed images suspicious for prosthetic valve endocarditis. In 4 out of 6 patients valve replacement was done with histology confirming the prosthetic valve endocarditis diagnosis. After an adequate course of antibiotic therapy fluorodeoxyglucose positron emission tomography showed resolution of prosthetic valve endocarditis in all the patients.ConclusionOur experience confirms the potential role of fluoroseoxyglucose positron emission tomography in the diagnosis and follow-up of prosthetic valve endocarditis.

Considerations About Antimicrobial Stewardship in Settings with Epidemic Extended-Spectrum β-Lactamase-Producing or Carbapenem-Resistant Enterobacteriaceae

Infections caused by gram-negative bacteria (GNB) resistant to multiple classes of antibiotics are increasing in many hospitals. Extended-spectrum β-lactamase (ESBL)-producing and carbapenem-resistant Enterobacteriaceae in particular are now endemic in many parts of the world and represent a serious public health threat. In this era, antimicrobial stewardship programs are essential as targeted and responsible use of antibiotics improves patient outcomes and hopefully limits the selective pressure that drives the further emergence of resistance. However, some stewardship strategies aimed at promoting carbapenem-sparing regimens remain controversial and are difficult to implement when resistance rates to non-carbapenem antibiotics are increasing. Coordinated efforts between stewardship programs and infection control are essential for reversing conditions that favor the emergence and dissemination of multidrug-resistant GNB within the hospital and identifying extra-institutional “feeder reservoirs” of resistant strains such as long-term care facilities, where colonization is common despite limited numbers of serious infections. In settings where ESBL resistance is endemic, the cost-effectiveness of expanded infection control efforts and antimicrobial stewardship is still unknown. Once a patient has been colonized, selective oral or digestive decontamination may be considered, but evidence supporting its effectiveness is limited in patients who are already colonized or in centers with high rates of resistance. Moreover, temporary success at decolonization may be associated with a higher risk of relapse with strains that are resistant to the decolonizing antibiotics.