Sara Tedeschi

Predictors of Mortality in Bloodstream Infections Caused by Klebsiella pneumoniae Carbapenemase–Producing K. pneumoniae: Importance of Combination Therapy

BACKGROUND The spread of Klebsiella pneumoniae (Kp) strains that produce K. pneumoniae carbapenemases (KPCs) has become a significant problem, and treatment of infections caused by these pathogens is a major challenge for clinicians. METHODS In this multicenter retrospective cohort study, conducted in 3 large Italian teaching hospitals, we examined 125 patients with bloodstream infections (BSIs) caused by KPC-producing Kp isolates (KPC-Kp) diagnosed between 1 January 2010 and 30 June 2011. The outcome measured was death within 30 days of the first positive blood culture. Survivor and nonsurvivor subgroups were compared to identify predictors of mortality. RESULTS The overall 30-day mortality rate was 41.6%. A significantly higher rate was observed among patients treated with monotherapy (54.3% vs 34.1% in those who received combined drug therapy; P = .02). In logistic regression analysis, 30-day mortality was independently associated with septic shock at BSI onset (odds ratio [OR]: 7.17; 95% confidence interval [CI]: 1.65-31.03; P = .008); inadequate initial antimicrobial therapy (OR: 4.17; 95% CI: 1.61-10.76; P = .003); and high APACHE III scores (OR: 1.04; 95% CI: 1.02-1.07; P < .001). Postantibiogram therapy with a combination of tigecycline, colistin, and meropenem was associated with lower mortality (OR: 0.11; 95% CI: .02-.69; P = .01). CONCLUSIONS KPC-Kp BSIs are associated with high mortality. To improve survival, combined treatment with 2 or more drugs with in vitro activity against the isolate, especially those also including a carbapenem, may be more effective than active monotherapy.

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.

Sexual disparities in the incidence and course of SLE and RA

Systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA) disproportionately affect females compared to males, with female to male prevalence ratios of 7-9:1 for SLE and 2-3:1 for RA. Interestingly, epidemiologic studies indicate that men that develop SLE may have more morbidity than women, but the same is not true for RA. Given the sex and age bias of SLE and RA, sex hormones may influence the pathogenesis of these diseases. However, the ways in which, and to what degree, sex hormones affect disease incidence and severity remain unclear and is the topic of ongoing research. Recent findings have implicated interactions between sex hormones, the immune system, genetic factors, and epigenetic modifications in influencing SLE and RA disease activity. This article reviews current hypotheses regarding the potential impact of sex hormones and genetics on disease pathogenesis, incidence, and severity of SLE and RA.

Relationship Between Maternal and Neonatal Staphylococcus aureus Colonization

OBJECTIVE: The study aimed to assess whether maternal colonization with Staphylococcus aureus during pregnancy or at delivery was associated with infant staphylococcal colonization. METHODS: For this prospective cohort study, women were enrolled at 34 to 37 weeks of gestation between 2007 and 2009. Nasal and vaginal swabs for culture were obtained at enrollment; nasal swabs were obtained from women and their infants at delivery and 2- and 4-month postbirth visits. Logistic regression was used to determine whether maternal colonization affected infant colonization. RESULTS: Overall, 476 and 471 mother-infant dyads had complete data for analysis at enrollment and delivery, respectively. Maternal methicillin-resistant S aureus (MRSA) colonization occurred in 10% to 17% of mothers, with the highest prevalence at enrollment. Infant MRSA colonization peaked at 2 months of age, with 20.9% of infants colonized. Maternal staphylococcal colonization at enrollment increased the odds of infant staphylococcal colonization at birth (odds ratio; 95% confidence interval: 4.8; 2.4–9.5), hospital discharge (2.6; 1.3–5.0), at 2 months of life (2.7; 1.6–4.3), and at 4 months of life (2.0; 1.1–3.5). Similar results were observed for maternal staphylococcal colonization at delivery. Fifty maternal-infant dyads had concurrent MRSA colonization: 76% shared isolates of the same pulsed-field type, and 30% shared USA300 isolates. Only 2 infants developed staphylococcal disease. CONCLUSIONS: S aureus colonization (including MRSA) was extremely common in this cohort of maternal-infant pairs. Infants born to mothers with staphylococcal colonization were more likely to be colonized, and early postnatal acquisition appeared to be the primary mechanism.

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.

Tenofovir-induced renal toxicity in 324 HIV-infected, antiretroviral-naïve patients

Abstract To better evaluate the renal safety profile of tenofovir, we performed a retrospective study of HIV-infected antiretroviral-naïve patients starting a first antiretroviral therapy between July 2004 and July 2008, and followed-up for 24 months. The glomerular filtration rate (GFR) was calculated using the MDRD formula, and tubular dysfunction was diagnosed with 2 or more of the following: proteinuria, glucosuria, hypouricemia, hypophosphatemia and hypokalemia. Overall, 324 patients were enrolled: 201 were tenofovir-exposed and were compared with 123 tenofovir-unexposed subjects. In both the unadjusted and adjusted analyses, tenofovir-exposed subjects had a significantly greater decline in GFR and a significantly higher incidence of proximal tubular dysfunction through 24 months. Reduced glomerular and tubular functions were significantly associated with older age, diabetes, hypertension and concomitant therapy with a protease inhibitor.

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.