MITO END-3: efficacy of avelumab immunotherapy according to molecular profiling in first-line endometrial cancer therapy.

BACKGROUND: Immunotherapy combined with chemotherapy significantly improves progression-free survival (PFS) compared to first-line chemotherapy alone in advanced endometrial cancer (EC), with a much larger effect size in microsatellite instability-high (MSI-H) cases. New biomarkers might help to select patients who may have benefit among those with a microsatellite-stable (MSS) tumor. PATIENTS AND METHODS: In a pre-planned translational analysis of the MITO END-3 trial, we assessed the significance of genomic abnormalities in patients randomized to standard carboplatin/paclitaxel without or with avelumab. RESULTS: Out of 125 randomized patients, 109 had samples eligible for next-generation sequencing analysis, and 102 had MSI tested. According to The Cancer Genome Atlas (TCGA), there were 29 cases with MSI-H, 26 with MSS TP53 wild type (wt), 47 with MSS TP53 mutated (mut), and 1 case with POLE mutation. Four mutated genes were present in >30% of cases: TP53, PIK3CA, ARID1A, and PTEN. Eleven patients (10%) had a BRCA1/2 mutation (five in MSI-H and six in MSS). High tumor mutational burden (≥10 muts/Mb) was observed in all MSI-H patients, in 4 out of 47 MSS/TP53 mut, and no case in the MSS/TP53 wt category. The effect of avelumab on PFS significantly varied according to TCGA categories, being favorable in MSI-H and worst in MSS/TP53 mut (P interaction = 0.003); a similar non-significant trend was seen in survival analysis. ARID1A and PTEN also showed a statistically significant interaction with treatment effect, which was better in the presence of the mutation (ARID1A P interaction = 0.01; PTEN P interaction = 0.002). CONCLUSION: The MITO END-3 trial results suggest that TP53 mutation is associated with a poor effect of avelumab, while mutations of PTEN and ARID1A are related to a positive effect of the drug in patients with advanced EC.

Antifungal prophylaxis in liver transplant recipients: one size does not fit all.

BACKGROUND: Targeted antifungal prophylaxis against Candida species or against Candida species and Aspergillus species, according to individual patient risk factors (RFs), is recommended by experts. However, recent studies have reported fluconazole is as effective as broader spectrum antifungals for preventing invasive fungal infection (IFI) after liver transplantation (LT). METHODS: We performed a retrospective cohort study of all adult patients who underwent LT at our 1420-bed tertiary teaching hospital, from June 2010 to December 2014, to assess the rate and etiology of IFI within 100 days after LT, to investigate the compliance with targeted prophylaxis, and to analyze risk factors for developing IFI. RESULTS: In total, 303 patients underwent LT. Patients were classified as having low (no RFs), intermediate (1 RF for invasive candidiasis [IC]), and high risk (1 RF for invasive aspergillosis [IA] or ≥2 RFs for IC) for IFI in 20%, 30%, and 50% of cases, respectively. A total of 139 patients received antifungal prophylaxis: 98 with a mold-active drug and 41 with fluconazole. Overall adherence to targeted prophylaxis was 53%. Nineteen patients (6.3%) developed IFI: 7 IC and 12 IA. Multivariate Cox regression analysis, adjusted for median model for end-stage liver disease score at LT, stratification risk group, and adherence to targeted prophylaxis, showed that graft dysfunction, renal replacement therapy, and prophylaxis with fluconazole were independent risk factors for IFI. Seven of the 9 patients who received fluconazole prophylaxis and developed IFI were classified as having high risk for IFI, and 6 developed IA. CONCLUSION: Recommended stratification is accurate for predicting patients at very high risk for IFI, who should receive prophylaxis with a mold-active drug.

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.

Emerging molecular alterations leading to histology-specific targeted therapies in ovarian cancer beyond PARP inhibitors.

After more than 30 years of a one-size-fits-all approach in the management of advanced ovarian cancer, in 2018 the SOLO1 trial results have introduced a new era of personalized medicine. A deeper knowledge of ovarian cancer biology and the development of new drugs targeting specific molecular pathways have led to biomarker-driven phase 3 trials with practice changing results. Thereafter, platinum-based combinations are no longer the only therapeutic options available in first line setting and poly-ADP ribose polymerase inhibitors maintenance therapy has become the mainstay in patients with tumor harboring a homologous recombination defect. However, most of the recent therapeutic breakthroughs regard high grade serous carcinoma, the most frequent ovarian cancer subtype, and only few improvements have occurred in the management of less common histotypes. Moving towards the next challenges, we aimed to investigate and review new potential molecular targets in ovarian cancer, according to histotype, starting from promising molecular drivers and matched drugs that have been investigated in early and late-stage clinical trials or conceptualized in preclinical studies.

Risk factors for candidaemia in hospitalized patients with liver cirrhosis: a multicentre case-control-control study.

OBJECTIVES: The aim of this study was to evaluate the risk factors for candidaemia in patients with liver cirrhosis. METHODS: This was a case-control-control (1:2:2) study performed in four Italian tertiary centres from 2006 to 2015. Cases were patients with liver cirrhosis developing candidaemia. For every case of candidaemia we enrolled two additional patients undergoing blood cultures for suspected infection yielding isolation of a bacterial pathogen (control A) and two additional patients undergoing blood cultures for suspected infection yielding negative results (control B). Patients were matched according to age, sex and model for end stage liver disease at hospital admission. RESULTS: During the study period 90 cases, 180 controls A and 180 controls B were included. At multivariate analysis assessed by means of multinomial conditional regression models, factors independently associated with candidaemia were previous (<30 days) acute-on-chronic liver failure (relative risk ratio (RRR) 2.22 (95% confidence interval (CI) 1.09-4.54), p = 0.046), previous(<30 days) gastrointestinal endoscopy (RRR 2.38 (95% CI 1.19-4.78) p = 0.014), previous(<30 days) antibiotic treatment for at least 7 days (RRR 2.74 (95% CI 1.00-7.48), p = 0.049), presence of central venous catheter (RRR 2.77 (95% CI 1.26-6.09, p = 0.011), total parenteral nutrition (RRR 3.90 (95% CI 1.62-9.40), p = 0.002) at infection onset and length of in-hospital stay >15 days (RRR 4.63 (95% CI 2.11-10.18), p <0.001] Conversely, rifaximin treatment was associated with lower rate of candidaemia (RRR 0.38 (95% CI 0.19-0.77), p = 0.007). Multivariable analysis for 30-day mortality showed that patients with isolation of Candida spp. from blood cultures had worse outcome when compared with controls even though the difference did not reach a statistical significance (hazard ratio 1.64 (95% 0.97-2.75) p = 0.06). CONCLUSIONS: We identified previous antibiotic use, gastrointestinal endoscopy or acute-on-chronic liver failure and presence of central venous catheter especially for parenteral nutrition as independent factors associated with candidaemia. Surprisingly, chronic rifaximin use was a protective factor.

Advances in the therapy of bacterial bloodstream infections.

BACKGROUND: Advances in the diagnostic and therapeutic management of patients with bloodstream infections (BSIs) have been achieved in the last years, improving clinical outcome. However, mortality associated with some pathogens, such as Staphylococcus aureus and Enterococcus spp., is still high. In addition, the spread of antibiotic resistance, mainly among Gram-negative bacteria, reduces treatment options in some circumstances. Therefore, interest in new drugs, combination regimens and optimal dosing schedules is rising. OBJECTIVES: Our aim is to summarize the current evidence on available antibiotic regimens for patients with bacterial BSI, focusing on drug choice, combination regimens and optimal dosing schedules. We selected bacteria that are difficult to manage because of virulence factors (i.e. methicillin-susceptible S. aureus), tolerance to antibiotic activity (i.e. Enterococcus faecalis), and/or susceptibility patterns (i.e. methicillin-resistant S. aureus, vancomycin-resistant enterococci, carbapenem-resistant Enterobacteriaceae, multidrug-resistant Pseudomonas aeruginosa and carbapenem-resistant Acinetobacter baumannii). SOURCES: MEDLINE search with English language and publication in the last 5 years as limits. CONTENT AND IMPLICATIONS: The literature gaps on the use of new drugs, the uncertainties regarding the use of combination regimens, and the need to optimize dosing schedules in some circumstances (e.g. augmented renal clearance, renal replacement therapy, high inoculum BSI sources, and isolation of bacteria showing high MICs) have been revised.

Serum bactericidal titres for monitoring antimicrobial therapy: current status and potential role in the management of multidrug-resistant Gram-negative infections.

BACKGROUND: Serum bactericidal titres (SBTs) were widely used in the 1970s and 1980s to monitor antimicrobial therapy but are now seldom recommended. It is the only laboratory test that integrates drug pharmacodynamics, host pharmacokinetics and synergistic or antagonistic interactions of antimicrobial combinations into a single index of antimicrobial activity. We hypothesized that SBTs could play a renewed role in monitoring antibiotic treatment of multidrug-resistant Gram-negative infections. However, the last critical appraisal of the test was published over 30 years ago. OBJECTIVES: This narrative review provides an updated assessment of the SBT test and its methodological limitations. We performed a diagnostic meta-analysis to estimate the value of SBTs for predicting clinical failure or death during antibiotic treatment. SOURCES: A comprehensive literature search of PubMed including all English publications was performed in December 2019 using the Medical Subject Headings (MeSH search terms "serum", "bactericidal", "inhibitory", "titre", "monitoring", "anti-infective agents" "antimicrobial therapy" and "therapeutic drug monitoring"). CONTENT: Although standardized methods for performing SBTs were approved in 1999, the test remains labour intensive, and results may not be available until 72 hr. However, the use of non-culture-based endpoints (i.e. spectrophotometric or fluorescent) may shorten test time to 24 hr. Despite considerable heterogeneity in published studies, a meta-analysis of 11 evaluable studies published from 1974 to 2007 indicated a critical SBT result (peak SBT ≤1:8 or trough ≤1:2) is associated with a diagnostic odds ratio for clinical failure during antibiotic treatment of 12.27 (95% confidence interval 5.28-28.54) and a 5.32 (95% 1.32-21.42) odds of death. IMPLICATIONS: SBTs have prognostic value for identifying patients at high risk for antibiotic treatment failure, but the slow turnaround time of the current test limits its clinical utility. Standardization of a more rapid SBT testing method is needed.

Follow-up blood cultures are associated with improved outcome of patients with gram-negative bloodstream infections: retrospective observational cohort study.

OBJECTIVES: We examined factors associated with follow-up blood cultures (FUBCs) in patients with monomicrobial Gram-negative (GN) bloodstream infection (BSI) and investigated the impact of FUBCs on therapeutic management and patient outcome. METHODS: A retrospective cohort analysis was conducted of adult patients diagnosed with GN-BSI at a tertiary-care university hospital during 2013-2016. FUBCs performed between 24 hours and 7 days after index BCs was the exposure variable. Risk factors for 30-day mortality were analysed by multivariate Cox analysis on the overall cohort, including FUBCs as a time-varying covariate and on 1:1 matched patients according to Sequential Organ Failure Assessment (SOFA) score and time to FUBC. RESULTS: In 278 (17.6%) of 1576 patients, FUBCs were performed within a median of 3 and 2 days after index BCs and active antibiotic therapy initiation. Persistent BSI was found in 107 (38.5%) of 278 patients. FUBCs were performed in more severely ill patients, with nonurinary sources, difficult-to-treat pathogens and receipt of initial inappropriate therapy. Source control and infectious disease consultation rates were higher among patients with preceding FUBCs and was associated with longer treatment duration. Thirty-day mortality was 10.4%. Independent risk factors for mortality were Charlson comorbidity index (hazard ratio (HR) 1.12) SOFA (HR 1.11), septic shock (HR 2.64), urinary source (HR 0.60), central venous catheter source (HR 2.30), complicated BSI (HR 2.10), carbapenem resistance (HR 2.34), active empiric therapy (HR 0.68), source control (HR 0.34) and FUBCs (HR 0.48). Association between FUBCs and lower mortality was confirmed in the 274 matched pairs. CONCLUSIONS: FUBCs were performed in more severe GN-BSIs, yielding a high rate of persistent BSI. In this context, FUBCs were associated with lower mortality.

The impact of carbapenemase-producing Enterobacteriaceae colonization on infection risk after liver transplantation: a prospective observational cohort study.

OBJECTIVE: To investigate the impact of colonization with carbapenemase-producing Enterobacteriaceae (CPE) on the CPE infection risk after liver transplantation (LT). METHODS: Prospective cohort study of all adult patients undergoing LT at our centre over an 8-year period (2010-2017). Individuals were screened for CPE colonization by rectal swabs at inclusion onto the waiting list, immediately before LT and weekly after LT until hospital discharge. Asymptomatic carriers did not receive decolonization, anti-CPE prophylaxis or pre-emptive antibiotic therapy. Participants were followed up for 1 year after LT. RESULTS: We analysed 553 individuals who underwent a first LT, 38 were colonized with CPE at LT and 104 acquired colonization after LT. CPE colonization rates at LT and acquired after LT increased significantly over the study period: incidence rate ratios (IRR) 1.21 (95% CI 1.05-1.39) and 1.17 (95% CI 1.07-1.27), respectively. Overall, 57 patients developed CPE infection within a median of 31 (interquartile range 11-115) days after LT, with an incidence of 3.05 cases per 10 000 LT-recipient-days and a non-significant increase over the study period (IRR 1.11, 95% CI 0.98-1.26). In multivariable analysis, CPE colonization at LT (hazard ratio (HR) 18.50, 95% CI 6.76-50.54) and CPE colonization acquired after LT (HR 16.89, 95% CI 6.95-41.00) were the strongest risk factors for CPE infection, along with combined transplant (HR 2.60, 95% CI 1.20-5.59), higher Model for End-Stage Liver Disease at the time of LT (HR 1.03, 95% CI 1.00-1.07), prolonged mechanical ventilation (HR 2.63, 95% CI 1.48-4.67), re-intervention (HR 2.16, 95% CI 1.21-3.84) and rejection (HR 2.81, 95% CI 1.52-5.21). CONCLUSIONS: CPE colonization at LT or acquired after LT were the strongest predictors of CPE infection. Prevention strategies focused on LT candidates and recipients colonized with CPE should be investigated.

Treatment duration for Escherichia coli bloodstream infection and outcomes: retrospective single-centre study.

OBJECTIVES: To investigate the impact of treatment duration on mortality and on relapse in patients with Escherichia coli bloodstream infection (BSI). METHODS: Retrospective single-centre study of patients diagnosed with E. coli BSI at our centre over a 4-year period. EXCLUSION CRITERIA: age <18 years, clinical data not available, polymicrobial BSI, failure to receive in vitro active therapy, and death while receiving antibiotic therapy. Exposure variable was treatment duration dichotomized into short (≤10 days) and long (>10 days) therapy. Primary end point was all-cause mortality within 90 days after index BSI. Secondary end point was relapse, defined as repeat isolation of E. coli from blood cultures within 90 days after index BSI, in patients with documented clinical cure and completion of therapy for the initial episode. RESULTS: Of the 856 analysed patients: 426 received short and 430 received long therapy. All-cause mortality at day 90 occurred in 47 patients; on multivariate analysis, short therapy was not associated with a higher risk of mortality, also after adjusting the model for the propensity score of receiving short therapy. Relapse occurred in 42 patients. Independent risk factors for relapse using death as competing risk were immunosuppression (subhazard ratio 4.67, p < 0.001), and end-stage liver disease (subhazard ratio 2.58, p 0.013). The propensity-weighted estimation of the average treatment effect for relapse reduction with long therapy (>10 days) was -1.6% (p 0.26) in the total population, and -7.1% (p 0.18) in immunocompromised patients. CONCLUSIONS: We could not identify shorter treatment duration as a risk factor for mortality and for relapse in patients with E. coli BSI.

A prospective multicentre study of the epidemiology and outcomes of bloodstream infection in cirrhotic patients.

OBJECTIVES: To describe the current epidemiology of bloodstream infection (BSI) in patients with cirrhosis; and to analyse predictors of 30-day mortality and risk factors for antibiotic resistance. METHODS: Cirrhotic patients developing a BSI episode were prospectively included at 19 centres in five countries from September 2014 to December 2015. The discrimination of mortality risk scores for 30-day mortality were compared by area under the receiver operator risk and Cox regression models. Risk factors for multidrug-resistant organisms (MDRO) were assessed with a logistic regression model. RESULTS: We enrolled 312 patients. Gram-negative bacteria, Gram-positive bacteria and Candida spp. were the cause of BSI episodes in 53%, 47% and 7% of cases, respectively. The 30-day mortality rate was 25% and was best predicted by the Sequential Organ Failure Assessment (SOFA) and Chronic Liver Failure-SOFA (CLIF-SOFA) score. In a Cox regression model, delayed (>24 hours) antibiotic treatment (hazard ratio (HR) 7.58; 95% confidence interval (CI) 3.29-18.67; p < 0.001), inadequate empirical therapy (HR 3.14; 95% CI 1.93-5.12; p < 0.001) and CLIF-SOFA score (HR 1.35; 95% CI 1.28-1.43; p < 0.001) were independently associated with 30-day mortality. Independent risk factors for MDRO (31% of BSIs) were previous antimicrobial exposure (odds ratio (OR) 2.91; 95% CI 1.73-4.88; p < 0.001) and previous invasive procedures (OR 2.51; 95% CI 1.48-4.24; p 0.001), whereas spontaneous bacterial peritonitis as BSI source was associated with a lower odds of MDRO (OR 0.30; 95% CI 0.12-0.73; p 0.008). CONCLUSIONS: MDRO account for nearly one-third of BSI in cirrhotic patients, often resulting in delayed or inadequate empirical antimicrobial therapy and increased mortality rates. Our data suggest that improved prevention and treatment strategies for MDRO are urgently needed in the liver cirrhosis patients.

Superficial swab versus deep-tissue biopsy for the microbiological diagnosis of local infection in advanced-stage pressure ulcers of spinal-cord-injured patients: a prospective study.

OBJECTIVE: To assess the predictive value of superficial ulcer swab culture to make a microbiological diagnosis of deep wound infections in spinal cord injury (SCI) patients with advanced-stage pressure ulcers. METHODS: From July 2011 to February 2014, we performed a prospective, single-centre study on adult SCI patients undergoing scheduled surgical debridement and reconstruction for advanced-stage pressure ulcers, at Montecatone Rehabilitation Institute, a 150-bed hospital dedicated to SCI care. Three superficial ulcer swabs were preoperatively collected using the Levine technique, then sent for culture. In surgery, multiple bone and soft-tissue specimens were taken and sent for culture and histological examination. No antibiotics were administered before surgery. The results of swabs and intraoperative specimens were compared. RESULTS: In all, 116 patients were included, median age 49 years; a majority were males with post-traumatic paraplegia. According to intraoperative specimen cultures, the most common micro-organisms were Staphylococcus aureus, Proteus mirabilis, and Pseudomonas aeruginosa, found in 31, 27, and 16 cases, respectively. Concordance between superficial swabs and intraoperative specimen culture was found in only in 25 out of 116 cases (22%). The main reason for non-concordance was the yielding of different micro-organisms (41 out of 116); false negatives (swab negative/intraoperative positive) accounted for 31 out of 116 and false positives (swab positive/intraoperative negative) for 19 out of 116. When compared with intraoperative specimens, sensitivity and specificity of the swab culture were 80% and 54%, respectively. CONCLUSIONS: Our results confirm that in patients with advanced-stage pressure ulcers, the cultures of a superficial ulcer swab are not useful in either the diagnosis of a superinfection or the prediction of the role of involved micro-organisms.

Characterization of antibody response in neuroinvasive infection caused by Toscana virus.

OBJECTIVES: Among sandfly-borne pathogens, Toscana virus (TOSV) is a prominent cause of summer meningitis in Mediterranean Europe. Here, we assessed the kinetics of anti-TOSV antibodies over time in 41 patients diagnosed with TOSV meningitis or meningoencephalitis in northeastern Italy. METHODS: Acute and follow-up serum samples were collected up to 20 months after diagnosis of TOSV infection and tested for the presence of specific antibody using immunoenzymatic and indirect immunofluorescence assays. In addition, maturation of anti-TOSV IgG over time was evaluated as well as production of neutralizing antibodies. RESULTS: Specific IgM and IgG response was present at diagnosis in 100% of patients; TOSV-specific IgM and IgG were detected in patients' sera up to 6 and 20 months after diagnosis, respectively. The avidity index (AI) increased over the first month after infection in 100% of patients and most cases exceeded 60% by Day 30 post infection. The AI subsequently plateaued then declined at 20 months after diagnosis. Finally, neutralization assay to TOSV was performed in 217 sera collected from 41 patients; 69.6% of tested samples resulted in reactive and moderate levels of neutralizing antibodies observed during all phases of infection despite high titres of total anti-TOSV IgG. CONCLUSIONS: Specific antibody response develops rapidly and is long-lasting for neuroinvasive TOSV infection. Serodiagnosis of neuroinvasive TOSV requires simultaneous detection of specific IgM and IgG. Moderate levels of neutralizing antibodies were maintained over the study period, while the protective role of antibodies lacking neutralizing activity is unclear and requires further evaluation.

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 bloodstream infections due to colistin-resistant KPC-producing Klebsiella pneumoniae: results from a multicenter case-control-control study.

The increasing prevalence of colistin resistance (ColR) Klebsiella pneumoniae carbapenemase (KPC)-producing K. pneumoniae (Kp) is a matter of concern because of its unfavourable impact on mortality of KPC-Kp bloodstream infections (BSI) and the shortage of alternative therapeutic options. A matched case-control-control analysis was conducted. The primary study end point was to assess risk factors for ColR KPC-Kp BSI. The secondary end point was to describe mortality and clinical characteristics of these infections. To assess risk factors for ColR, 142 patients with ColR KPC-Kp BSI were compared to two controls groups: 284 controls without infections caused by KPC-Kp (control group A) and 284 controls with colistin-susceptible (ColS) KPC-Kp BSI (control group B). In the first multivariate analysis (cases vs. group A), previous colistin therapy, previous KPC-Kp colonization, ≥3 previous hospitalizations, Charlson score ≥3 and neutropenia were found to be associated with the development of ColR KPC-Kp BSI. In the second multivariate analysis (cases vs. group B), only previous colistin therapy, previous KPC-Kp colonization and Charlson score ≥3 were associated with ColR. Overall, ColR among KPC-Kp blood isolates increased more than threefold during the 4.5-year study period, and 30-day mortality of ColR KPC-Kp BSI was as high as 51%. Strict rules for the use of colistin are mandatory to staunch the dissemination of ColR in KPC-Kp-endemic hospitals.

Further evidence for a motility substitution test as a tool to detect the narcotic character of new drugs in rats.

Time effects of three doses of codeine, d-propoxyphene, meperidine and dextromethorphan upon locomotor activity have been investigated in naive rats as well as in animals treated chronically with 20 mg/kg of morphine daily. The first three drugs exhibited a motility pattern qualitatively similar to that of morphine; in chronically-treated rats cross-tolerance occurred to acute depressant effects and cross-sensitization to acute excitatory effects. In the case of meperidine however cross-sensitization appeared to be small. Dextromethorphan presented effects similar to morphine only in a very large dose. The present data, together with those of previous work, demonstrate that a locomotor activity substitution test may predict the morphine-like addictive properties of a drug.

Long-term sensitization to the excitatory effects of morphine. A motility study in post-dependent rats.

Motility effects of excitatory and depressant doses of morphine were studied in naïve, dependent (20 mg/kg daily) and post-dependent (about 40 days after withdrawal) rats. Doses of 0.6 and 1.25 mg/kg of morphine produced a greater increase in activity in post-dependent than in naïve rats. A 20-mg/kg dose exerted an excitatory effect in dependent rats instead of the depressant one induced in naïve animals. This excitatory effect was still evident but less pronounced in post-dependent rats. The dose of 1.25 mg/kg was repeatedly challenged in post-dependent (80 mg/kg daily) rats. It was found that the increased excitatory effect of this dose persisted unchanged 160 days after ceasing treatment. The present results demonstrate that several months after the withdrawal of morphine, sensitization still exists to the excitatory effect of the drug while tolerance to the depressant action is slight or no longer present shortly after ceasing treatment.

Previous treatment with morphine and sensitization to the excitatory actions of opiates: dose-effect relationship.

The stimulatory effect of morphine on locomotor activity has been shown to be largely modified in rats that have been formerly dependent on this drug. In the present study, the relationship between the chronic dose of morphine and the degree of sensitization to the excitatory effect of opiates was investigated. To this end, four groups of rats were treated daily for 30 days with 1.25, 5, 20 and 80 mg/kg of morphine (i.p.) and challenged with morphine (1.25 and 2.5 mg/kg) or fentanyl (40 and 80 micrograms/kg) 1-4 months after ceasing the treatment. Drug-induced hypermotility in post-dependent rats appeared to be linearly related to the dose of the preceding chronic treatment after test doses of both morphine and fentanyl. The results are discussed in terms of a persistent dose-related modification of the neuronal mechanism subserving the excitatory component of the action of opiates; such a modification might offer a neurobiological basis for the fact that "relapse tendencies" for opiates persist for a long time after withdrawal.