Ceftazidime/avibactam-resistant meropenem-susceptible KPC-producing Klebsiella pneumoniae: Analysis of cases and evaluation of in vitro activity of fosfomycin-containing combinations.

OBJECTIVES: Little is known regarding outcomes and optimal therapeutic regimens of infections caused by Klebsiella pneumoniae carbapenemase-producing Klebsiella pneumoniae (KPC-Kp) resistant to ceftazidime/avibactam (CZA) and susceptible to meropenem (MEM). Although susceptible to MEM in vitro, the possibility of developing MEM resistance overtime is a concern. We describe the clinical characteristics of patients with colonization/infection due to KPC variants with a focus on the in vitro activity of fosfomycin (FOS)-containing combinations. METHODS: Patients with colonization/infection due to a KPC variant were included. Fosfomycin susceptibility was performed by agar dilution method. Synergistic activity of FOS-based combinations was evaluated by gradient strip-agar diffusion method. The emergence of in vitro MEM resistance was also tested. RESULTS: Eleven patients were included: eight with infection [four with ventilator-associated pneumonia and four with bloodstream infections] and three with colonization. Previous therapy with CZA was administered to all patients (with a mean cumulative duration of 23 days). All subjects with infection received meropenem, in monotherapy (n = 4) or with amikacin (n = 2) or fosfomycin (n = 2), and achieved clinical cure. A new CZA-susceptible and MEM-resistant KPC-Kp strain was subsequently isolated in three patients (27.3%). Meropenem/vaborbactam (MVB) showed high in vitro activity, while FOS+MEM combination was synergistic in 40% of cases. In vitro resistance to MEM was observed with maintenance of CZA resistance. CONCLUSIONS: Detection of KPC variants may occur within the same patient, especially if CZA has been previously administered. Although clinical success has been obtained with carbapenems, the emergence of MEM resistance is a concern. Fosfomycin plus meropenem is synergistic and may be a valuable combination option for KPC variants, while MVB may be considered in monotherapy. The detection of KPC variants in an endemic setting for KPC-Kp represents a worryingly emerging condition. The optimal therapeutic approach is still unknown and the development of meropenem resistance is of concern, which may lead to therapeutic failure in clinical practice. In these cases, the addition of fosfomycin to meropenem, or a more potent antibiotic, such as meropenem/vaborbactam, may be valuable therapeutic options.

Effect of ceftazidime/avibactam plus fosfomycin combination on 30†day mortality in patients with bloodstream infections caused by KPC-producing Klebsiella pneumoniae: results from a multicentre retrospective study.

Introduction: The primary outcome of the study was to evaluate the effect on 30 day mortality of the combination ceftazidime/avibactam + fosfomycin in the treatment of bloodstream infections (BSIs) caused by KPC-producing Klebsiella pneumoniae (KPC-Kp). Materials and methods: From October 2018 to March 2021, a retrospective, two-centre study was performed on patients with KPC-Kp BSI hospitalized at Sapienza University (Rome) and ISMETT-IRCCS (Palermo) and treated with ceftazidime/avibactam-containing regimens. A matched cohort (1:1) analysis was performed. Cases were patients receiving ceftazidime/avibactam + fosfomycin and controls were patients receiving ceftazidime/avibactam alone or in combination with in vitro non-active drugs different from fosfomycin (ceftazidime/avibactam ±â€Šother). Patients were matched for age, Charlson comorbidity index, ward of isolation (ICU or non-ICU), source of infection and severity of BSI, expressed as INCREMENT carbapenemase-producing Enterobacteriaceae (CPE) score. Results: Overall, 221 patients were included in the study. Following the 1:1 match, 122 subjects were retrieved: 61 cases (ceftazidime/avibactam + fosfomycin) and 61 controls (ceftazidime/avibactam ±â€Šother). No difference in overall mortality emerged between cases and controls, whereas controls had more non-BSI KPC-Kp infections and a higher number of deaths attributable to secondary infections. Almost half of ceftazidime/avibactam + fosfomycin patients were prescribed fosfomycin without MIC fosfomycin availability. No difference in the outcome emerged after stratification for fosfomycin susceptibility availability and dosage. SARS-CoV-2 infection and ICS ≥ 8 independently predicted 30 day mortality, whereas an appropriate definitive therapy was protective. Conclusions: Our data show that fosfomycin was used in the treatment of KPC-Kp BSI independently from having its susceptibility testing available. Although no difference was found in 30 day overall mortality, ceftazidime/avibactam + fosfomycin was associated with a lower rate of subsequent KPC-Kp infections and secondary infections than other ceftazidime/avibactam-based regimens.

Clinical course of Coronavirus Disease-19 in patients with haematological malignancies is characterized by a longer time to respiratory deterioration compared to non-haematological ones: results from a case-control study.

BACKGROUND: We evaluated clinical features and risk factors for mortality in patients with haematological malignancies and COVID-19. METHODS: Retrospective, case-control (1:3) study in hospitalized patients with COVID-19. Cases were patients with haematological malignancies and COVID-19, controls had COVID-19 without haematological malignancies. Patients were matched for sex, age and time of hospitalization. RESULTS: Overall, 66 cases and 198 controls were included in the study. Cases had higher prior corticosteroid use, infection rates, thrombocytopenia and neutropenia and more likely received corticosteroids and antibiotics than controls. Cases had higher respiratory deterioration than controls (78.7% vs 65.5%, p = 0.04). Notably, 29% of cases developed respiratory worsening > 10 days after hospital admission, compared to only 5% in controls. Intensive Care Unit admission and mortality were higher in cases than in controls (27% vs 8%, p = 0.002, and 35% vs 10%, p < 0.001). At multivariable analysis, having haematological malignancy [OR4.76, p < 0.001], chronic corticosteroid therapy [OR3.65, p = 0.004], prior infections [OR57.7, p = 0.006], thrombocytopenia [OR3.03, p < 0.001] and neutropenia [OR31.1, p = 0.001], low albumin levels [OR3.1, p = 0.001] and ≥ 10 days from hospital admission to respiratory worsening [OR3.3, p = 0.002] were independently associated with mortality. In cases, neutropenia [OR3.1, p < 0.001], prior infections [OR7.7, p < 0.001], ≥ 10 days to respiratory worsening [OR4.1, p < 0.001], multiple myeloma [OR1.5, p = 0.044], the variation of the CT lung score during hospitalization [OR2.6, p = 0.006] and active treatment [OR 4.4, p < 0.001] all were associated with a worse outcome. CONCLUSION: An underlying haematological malignancy was associated with a worse clinical outcome in COVID-19 patients. A prolonged clinical monitoring is needed, since respiratory worsening may occur later during hospitalization.

Rab5-dependent trafficking of the m4 muscarinic acetylcholine receptor to the plasma membrane, early endosomes, and multivesicular bodies.

The m4 subtype of muscarinic acetylcholine receptor regulates many physiological processes and is a novel therapeutic target for neurologic and psychiatric disorders. However, little is known about m4 regulation because of the lack of pharmacologically selective ligands. A crucial component of G protein-coupled receptor regulation is intracellular trafficking. We thus used subtype-specific antibodies and quantitative immunocytochemistry to characterize the intracellular trafficking of m4. We show that following carbachol stimulation, m4 co-localizes with transferrin, and the selective marker of early endosomes, EEA1. In addition, m4 intracellular localization depends on Rab5 activity. The dominant negative Rab5S34N inhibits m4 endocytosis initially following carbachol stimulation, and reduces the size of m4 containing vesicles. The constitutively active Rab5Q79L enhances m4 intracellular distribution, even in unstimulated cells. Rab5Q79L also produces strikingly enlarged vacuoles, which by electron microscopy contain internal vesicles, suggesting that they are multivesicular bodies. m4 localizes both to the perimeter and interior of these vacuoles. In contrast, transferrin localizes only to the vacuole perimeter, demonstrating divergence of m4 trafficking from the pathway followed by constitutively endocytosed transferrin. We thus suggest a novel model by which multivesicular bodies sort G protein-coupled receptors from a transferrin-positive recycling pathway to a nonrecycling, possibly degradative pathway.

Sensitization to daily morphine injections in rats with unilateral lesions of the substantia nigra.

Morphine indirectly enhances dopaminergic activity in the nigrostriatal system, and repeated administration of morphine progressively increases the locomotor activity of rats. We used the rotational behavior model to determine if daily morphine produces an increase in turning and produces cross-sensitization to d-amphetamine and cocaine. Rats with unilateral nigrostriatal lesions received daily injections of saline or morphine (10 mg/kg). Repeated morphine administration produced a progressive increase in turning over 13 days. Next, a morphine dose-response curve (1.0-30 mg/kg) was determined. Both the saline and morphine-treated groups showed dose-dependent increases in turning, but, the peak effect in the morphine group was higher than that in the saline group, indicating sensitization to morphine. The morphine-treated group did not show cross-sensitization to either d-amphetamine (0.1-3 mg/kg) or cocaine (1.0-30 mg/kg); in fact, it showed less cocaine-induced turning than the saline group. Seventy-one days after saline or morphine injections began, the morphine group was still significantly more sensitive to turning induced by 10 mg/kg morphine than the saline group was (200 vs. 750). Therefore, repeated daily injections of morphine produce a progressive sensitization to turning induced by morphine in the absence of cross-sensitization to turning induced by psychomotor stimulants.

A comparison of the effects of the opioid antagonists naltrexone, naltrindole, and beta-funaltrexamine on ethanol consumption in the rat.

The effects of the universal opioid antagonist naltrexone were compared to the delta-selective opioid antagonist naltrindole and the mu-selective opioid antagonist beta-funaltrexamine on ethanol consumption in the absence of food or fluid deprivation using a limited access procedure in Wistar rats. Both naltrexone, at doses of 0.1, 0.25, 0.5, 1.0, 3.0, and 10 mg/kg, and beta-funaltrexamine, at doses of 5.0 and 20.0 mg/kg, significantly decreased consumption of a 6% ethanol solution compared to saline control groups. Naltrindole, at doses of 5.0 and 15.0 mg/kg, failed to significantly reduce ethanol consumption. In addition, the highest doses of naltrexone, which antagonize delta as well as mu-opioid receptors, did not differ significantly from the lowest doses in their ability to reduce ethanol consumption. These data suggest that ethanol consumption using the limited access paradigm in the outbred rat is modulated by mu rather than delta-opioid receptors. Although this is not consistent with other data showing that delta antagonists decrease ethanol consumption, it is suggested that these difference may be related to the alcohol-preferring rats used in those experiments.

Naltrexone and alcohol dependence. Role of subject compliance.

BACKGROUND: Two previous double-blind, placebo-controlled studies demonstrated that naltrexone (50 mg/d) reduces alcohol drinking in alcohol-dependent subjects. In both studies, treatment compliance was excellent. However, a robust treatment effect size for naltrexone relative to placebo has been shown for compliant subjects but not for subjects who missed research visits. The goal of this study was to determine the effectiveness of naltrexone in subjects who received psychosocial treatment in a more naturalistic setting with respect to the role of treatment attendance and medication compliance. METHODS: Ninety-seven alcohol-dependent subjects were randomly assigned to receive either naltrexone (n = 48) or matching placebo (n = 49) for 12 weeks. All subjects received individual counseling (twice per week for the first month followed by once per week). RESULTS: Overall, naltrexone showed only modest effects in reducing alcohol drinking for the 12 weeks of treatment. However, naltrexone treatment efficacy improved across a variety of outcome measures for subjects who completed treatment and were highly compliant with taking medication. CONCLUSIONS: Naltrexone is clinically effective relative to placebo in individuals who comply with the treatment protocol and take medication. The modest treatment effects in the entire sample suggest that the clinical efficacy of naltrexone could be improved by enhancing treatment compliance.

Naltrexone in the treatment of alcoholism: a clinical review.

The pooled results from our Veterans Affairs studies are presented for 99 men. The naltrexone-treated subjects reported a reduction in alcohol craving and drinking, as well as less euphoria when they ingested alcohol. Relapse rates were significantly lower for the naltrexone-treated subjects than they were for placebo-treated subjects. Together with the consistent results from other double-blind trials of naltrexone, we conclude that naltrexone is a safe and useful adjunct in the rehabilitation of alcohol-dependent patients. Although administration of naltrexone was shown to improve treatment outcome, subjects who attended all 12 research visits demonstrated larger treatment effects. These data suggest that the use of naltrexone as a pharmacological adjunct to psychosocial intervention is an effective treatment for alcohol dependence. The effectiveness of naltrexone may be improved by designing a treatment program that enhances compliance with the medication.

Medical management of alcohol dependence: clinical use and limitations of naltrexone treatment.

Historically, pharmacological and psychosocial treatments for alcohol dependence have demonstrated only modest effectiveness in reducing alcohol drinking. However, the recent US Food and Drug Administration approval of naltrexone for the treatment of alcohol dependence offers a new, safe and effective medication to reduce relapse following alcohol detoxification. This paper reviews the various psychosocial and pharmacological treatments currently available and the effectiveness of these treatments. This paper also reviews preclinical research which demonstrates the involvement of the opioid system in the reinforcing effects of alcohol. This research led to clinical trials on the use of the opioid antagonist, naltrexone, to reduce alcohol's pleasurable effects and enhance the effectiveness of psychosocial therapy. In two randomized clinical trials, naltrexone treatment reduced rates of alcohol relapse, number of drinking days and alcohol craving. The clinical efficacy of all pharmacological treatments for substance abuse are limited by compliance with taking the medication. Also, pharmacological treatment does not address the psychosocial complications which often result from chronic alcohol dependence. Therefore, the integration of medications such as naltrexone and psychosocial therapies may offer the best treatment. The further development and investigation of new pharmacological agents will enable matching of patient populations with specific treatments, offering more successful treatment outcomes.

Opiates and alcohol self-administration in animals.

During the past 25 years, numerous animal studies have demonstrated a relationship between alcohol consumption and opiates. Converging lines of evidence suggest that (1) alcohol consumption enhances opioid receptor activity and (2) conditions associated with relative deficiencies in opioid receptor activity stimulate increases in alcohol preference. This evidence leads to the hypothesis that alcohol drinking is reinforced, in part, by enhanced opioid receptor activity; thus, these effects should be blocked by opiate antagonists. In fact, the animal data are consistent with this prediction. Opiate antagonists reduce excessive alcohol intake without reducing the ingestion of other biologically important reinforcers.

Ambulation levels of bilateral lower-extremity amputees. Analysis of one hundred and three cases.

One hundred and three bilateral lower-extremity amputees were evaluated to determine their eventual ambulation level. Of thirty-eight bilateral above-the-knee amputees, two with traumatic amputation were prosthetically rehabilitated, while none of the thirty-five with dysvascular amputation were so rehabilitated. Twenty-two of the dysvascular above-the-knee amputees were wheelchair ambulators and thirteen were bedridden. Prosthetic rehabilitation has been successful for traumatic bilateral above-the-knee amputees but has never been successful for our dysvascular bilateral above-the-knee amputees. The goal for dysvascular bilateral above-the-knee amputees is wheelchair ambulation. Of twenty-one patients with combinations of above-the-knee and below-the-knee amputations, five were prosthetically rehabilitated, including four dysvascular amputees; ten were wheelchair ambulators; and six were bedridden. Of forty-four patients with bilateral below-the-knee amputation, thirty-five were prosthetically rehabilitated and the remaining nine were wheelchair ambulators. Since the success rate for prosthetic rehabilitation is higher for amputees with combination above-the-knee and below-the-knee amputation than for those with bilateral above-the-knee amputation, and again increases for those with bilateral below-the-knee amputation, the significance of preserving the knee joint, even a single knee, cannot be overemphasized.