Real-life temocillin use in Greater Paris area, effectiveness and risk factors for failure in infections caused by ESBL-producing Enterobacterales: a multicentre retrospective study.

Background: Temocillin is a ß-lactam that is not hydrolysed by ESBLs. Objectives: To describe the real-life use of temocillin, to assess its effectiveness in infections caused by ESBL-producing Enterobacterales, and to identify risk factors for treatment failure. Methods: Retrospective multicentric study in eight tertiary care hospitals in the Greater Paris area, including patients who received at least one dose of temocillin for ESBL infections from 1 January to 31 December 2018. Failure was a composite criterion defined within 28 day follow-up by persistence or reappearance of signs of infection, and/or switch to suppressive antibiotic treatment and/or death from infection. A logistic regression with univariable and multivariable analysis was performed to identify risks associated with failure. Results: Data on 130 infection episodes were collected; 113 were due to ESBL-producing Enterobacterales. Mean age was 65.2 ±â€Š15.7 years and 68.1% patients were male. Indications were mostly urinary tract infections (UTIs) (85.8%), bloodstream infections (11.5%), respiratory tract infections (RTIs) (3.5%) and intra-abdominal infections (3.5%). Bacteria involved were Escherichia coli (49.6%), Klebsiella pneumoniae (44.2%) and Enterobacter cloacae (8.8%). Polymicrobial infections occurred in 23.0% of cases. Temocillin was mostly used in monotherapy (102/113, 90.3%). Failure was found in 13.3% of cases. Risk factors for failure in multivariable analysis were: RTI (aOR 23.3, 95% CI 1.5-358.2) and neurological disease (aOR 5.3, 95% CI 1.5-18.6). Conclusions: The main use of temocillin was UTI due to ESBL-producing E. coli and K. pneumoniae, with a favourable clinical outcome. The main risk factor for failure was neurological disease.

ATG-Fresenius increases the risk of red blood cell transfusion after kidney transplantation.

Introduction: In sensitized deceased donor kidney allograft recipients, the most frequent induction therapy is anti-thymocyte globulins (ATG), including Thymoglobulin® (Thymo) and ATG-Fresenius (ATG-F). Methods: We conducted a 3-year monocentric observational study to compare the impact of ATGs on hematological parameters. We included adult kidney transplant recipients treated with ATG induction therapy, either Thymo or ATG-F, on a one-in-two basis. The primary endpoint was red blood cell (RBC) transfusions within 14 days after transplantation. Results: Among 309 kidney allograft recipients, 177 (57.2%) received ATG induction, 90 (50.8 %) ATG-F, and 87 (49.2%) Thymo. The ATG-F group received significantly more RBC transfusions (63.3% vs. 46% p = 0.02) and in bigger volumes (p = 0.01). Platelet transfusion was similar in both groups. Within 14 and 30 days after transplantation, older age, ATG-F induction, and early surgical complication were independently associated with RBC transfusion. Patient survival rate was 95%, and the death-censored kidney allograft survival rate was 91.5% at 12 months post-transplantation. There was no difference in the incidence of acute rejection and infections or in the prevalence of anti-HLA donor-specific antibodies. Discussion: In conclusion, after kidney transplantation, ATG-F is an independent risk factor for early RBC transfusion and early thrombocytopenia without clinical and biological consequences. These new data should be clinically considered, and alternatives to ATG should be further explored.

Overly broad-spectrum antibiotic treatment of wild-type Pseudomonas aeruginosa infections in relation to the EUCAST new definition of susceptibility testing categories, a retrospective multicentre cohort study.

Objectives: EUCAST changed the definition of the 'intermediate' (I) category in 2019, now defined as 'susceptible, increased exposure'. This new definition could lead to an increased prescription of antibiotics still reported as 'S', compared with those now reported as 'I'. The objective of this study was to evaluate the influence of this definition on the use of overly broad-spectrum antibiotics for the treatment of infections caused by WT Pseudomonas aeruginosa. Methods: A retrospective observational multicentre study was conducted, involving five hospitals. Two 15 month study periods were defined, before and after the implementation of the new definition. All patients with an infection caused by WT P. aeruginosa treated by ß-lactams were included. The main endpoint was the proportion of patients treated by an overly broad-spectrum antibiotic treatment by meropenem or ceftolozane/tazobactam. Results: Two hundred and ninety-one patients were included. No difference between groups was found, in terms of infection, microbiology or demographic characteristics. Two overly broad-spectrum antibiotic treatments by meropenem or ceftolozane/tazobactam were observed in Period 1 (1.2%), versus 13 in Period 2 (10.8%; P < 0.001). No overly broad-spectrum treatment was observed when the antimicrobial stewardship team had given advice. Conclusions: This new definition can cause a negative impact on the use of overly broad-spectrum antibiotic treatment due to misunderstanding by clinicians. Its successful implementation requires adaptation of software for reporting antibiotic susceptibility, a sustained strong information campaign by microbiologists and support by an antimicrobial stewardship team.

Antibiotics in Necrotizing Soft Tissue Infections.

Necrotizing soft tissue infections (NSTIs) are rare life-threatening bacterial infections characterized by an extensive necrosis of skin and subcutaneous tissues. Initial urgent management of NSTIs relies on broad-spectrum antibiotic therapy, rapid surgical debridement of all infected tissues and, when present, treatment of associated organ failures in the intensive care unit. Antibiotic therapy for NSTI patients faces several challenges and should (1) carry broad-spectrum activity against gram-positive and gram-negative pathogens because of frequent polymicrobial infections, considering extended coverage for multidrug resistance in selected cases. In practice, a broad-spectrum beta-lactam antibiotic (e.g., piperacillin-tazobactam) is the mainstay of empirical therapy; (2) decrease toxin production, typically using a clindamycin combination, mainly in proven or suspected group A streptococcus infections; and (3) achieve the best possible tissue diffusion with regards to impaired regional perfusion, tissue necrosis, and pharmacokinetic and pharmacodynamic alterations. The best duration of antibiotic treatment has not been well established and is generally comprised between 7 and 15 days. This article reviews the currently available knowledge regarding antibiotic use in NSTIs.

Clinical efficacy of hydroxychloroquine in patients with covid-19 pneumonia who require oxygen: observational comparative study using routine care data.

OBJECTIVE: To assess the effectiveness of hydroxychloroquine in patients admitted to hospital with coronavirus disease 2019 (covid-19) pneumonia who require oxygen. DESIGN: Comparative observational study using data collected from routine care. SETTING: Four French tertiary care centres providing care to patients with covid-19 pneumonia between 12 March and 31 March 2020. PARTICIPANTS: 181 patients aged 18-80 years with documented severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pneumonia who required oxygen but not intensive care. INTERVENTIONS: Hydroxychloroquine at a dose of 600 mg/day within 48 hours of admission to hospital (treatment group) versus standard care without hydroxychloroquine (control group). MAIN OUTCOME MEASURES: The primary outcome was survival without transfer to the intensive care unit at day 21. Secondary outcomes were overall survival, survival without acute respiratory distress syndrome, weaning from oxygen, and discharge from hospital to home or rehabilitation (all at day 21). Analyses were adjusted for confounding factors by inverse probability of treatment weighting. RESULTS: In the main analysis, 84 patients who received hydroxychloroquine within 48 hours of admission to hospital (treatment group) were compared with 89 patients who did not receive hydroxychloroquine (control group). Eight additional patients received hydroxychloroquine more than 48 hours after admission. In the weighted analyses, the survival rate without transfer to the intensive care unit at day 21 was 76% in the treatment group and 75% in the control group (weighted hazard ratio 0.9, 95% confidence interval 0.4 to 2.1). Overall survival at day 21 was 89% in the treatment group and 91% in the control group (1.2, 0.4 to 3.3). Survival without acute respiratory distress syndrome at day 21 was 69% in the treatment group compared with 74% in the control group (1.3, 0.7 to 2.6). At day 21, 82% of patients in the treatment group had been weaned from oxygen compared with 76% in the control group (weighted risk ratio 1.1, 95% confidence interval 0.9 to 1.3). Eight patients in the treatment group (10%) experienced electrocardiographic modifications that required discontinuation of treatment. CONCLUSIONS: Hydroxychloroquine has received worldwide attention as a potential treatment for covid-19 because of positive results from small studies. However, the results of this study do not support its use in patients admitted to hospital with covid-19 who require oxygen.

Pharmacists' role in antimicrobial stewardship and relationship with antibiotic consumption in hospitals: An observational multicentre study.

OBJECTIVES: Antimicrobial stewardship (AMS) teams around the world include pharmacists; however, their impact is relatively unknown. This study aimed to explore the relationship between pharmacists' actions and antibiotic consumption. METHODS: Hospital pharmacists involved in the French antibiotic consumption surveillance network (ATB-Raisin) were invited to participate in a retrospective observational multicentre study. Collected data were: the previous year's (2016) antibiotic consumption expressed in daily defined dose per 1000 patient-days; AMS measures, including pharmacist-specific actions; and use of a computerised prescription order entry (CPOE) system. Associations between antibiotic consumption and AMS measures were assessed by linear regression, after adjustment for hospital activities. RESULTS: Annual data for 2016 from 77 hospitals (7260000 bed-days in 24000 beds) were analysed. Pharmacists were involved in AMS programs in 73% of hospitals, and were the antibiotic advisor in 25%. Pharmaceutical review of prescriptions was organised in almost all hospitals (97%). The univariable analysis identified five measures associated with lower overall antibiotic consumption: CPOE use (if >80% of prescriptions or 100%), pharmaceutical review (if >80% of beds or 100%) and the antibiotic advisor being a pharmacist (P=0.04, P=0.004 and P=0.003, respectively). In the multivariable analysis, two explanatory variables were significantly and independently associated with a lower overall antibiotic consumption: the antibiotic advisor being a pharmacist and a pharmaceutical review covering all beds (-19.9% [-31.6%; -8.1%], P=0.002 and -18.3% [-34.0%; -2.6%], P=0.03, respectively). CONCLUSIONS: Antibiotic consumption was lower when the antibiotic advisor was a pharmacist and when the pharmaceutical team reviewed all prescriptions. These results highlight that actions initiated by pharmacists have a positive impact and should be supported.

Inhibition Activity of Avibactam against Nocardia farcinica ß-Lactamase FARIFM10152.

Nocardia farcinica, one of the most frequent pathogenic species responsible for nocardiosis, is characterized by frequent brain involvement and resistance to ß-lactams mediated by a class A ß-lactamase. Kinetic parameters for hydrolysis of various ß-lactams by FARIFM10152 from strain IFM 10152 were determined by spectrophotometry revealing a high catalytic activity (kcat/Km ) for amoxicillin, aztreonam, and nitrocefin. For cephems, kcat/Km was lower but remained greater than 104 M-1 s-1 A low catalytic activity was observed for meropenem, imipenem, and ceftazidime hydrolysis. FARIFM10152 inhibition by avibactam and clavulanate was compared using nitrocefin as a reporter substrate. FARIFM10152 was efficaciously inhibited by avibactam with a carbamoylation rate constant (k2/Ki ) of (1.7 ± 0.3) × 104 M-1 s-1 The 50% effective concentrations (EC50s) of avibactam and clavulanate were 0.060 ± 0.007 µM and 0.28 ± 0.06 µM, respectively. Amoxicillin, cefotaxime, imipenem, and meropenem MICs were measured for ten clinical strains in the presence of avibactam and clavulanate. At 4 µg/ml, avibactam and clavulanate restored amoxicillin susceptibility in all but one of the tested strains but had no effect on the MICs of cefotaxime, imipenem, and meropenem. At 0.4 µg/ml, amoxicillin susceptibility (MIC ≤ 8 µg/ml) was restored for 9 out of 10 strains by avibactam but only for 4 out of 10 strains by clavulanate. Together, these results indicate that avibactam was at least as potent as clavulanate, suggesting that the amoxicillin-avibactam combination could be considered as an option for the rescue treatment of N. farcinica infections if clavulanate cannot be used.

Tryptophan Fluorescence Quenching in ß-Lactam-Interacting Proteins Is Modulated by the Structure of Intermediates and Final Products of the Acylation Reaction.

In most bacteria, ß-lactam antibiotics inhibit the last cross-linking step of peptidoglycan synthesis by acylation of the active-site Ser of d,d-transpeptidases belonging to the penicillin-binding protein (PBP) family. In mycobacteria, cross-linking is mainly ensured by l,d-transpeptidases (LDTs), which are promising targets for the development of ß-lactam-based therapies for multidrug-resistant tuberculosis. For this purpose, fluorescence spectroscopy is used to investigate the efficacy of LDT inactivation by ß-lactams but the basis for fluorescence quenching during enzyme acylation remains unknown. In contrast to what has been reported for PBPs, we show here using a model l,d-transpeptidase (Ldtfm) that fluorescence quenching of Trp residues does not depend upon direct hydrophobic interaction between Trp residues and ß-lactams. Rather, Trp fluorescence was quenched by the drug covalently bound to the active-site Cys residue of Ldtfm. Fluorescence quenching was not quantitatively determined by the size of the drug and was not specific of the thioester link connecting the ß-lactam carbonyl to the catalytic Cys as quenching was also observed for acylation of the active-site Ser of ß-lactamase BlaC from M. tuberculosis. Fluorescence quenching was extensive for reaction intermediates containing an amine anion and for acylenzymes containing an imine stabilized by mesomeric effect, but not for acylenzymes containing a protonated ß-lactam nitrogen. Together, these results indicate that the extent of fluorescence quenching is determined by the status of the ß-lactam nitrogen. Thus, fluorescence kinetics can provide information not only on the efficacy of enzyme inactivation but also on the structure of the covalent adducts responsible for enzyme inactivation.

Inhibition of ß-lactamases of mycobacteria by avibactam and clavulanate.

Objectives: Mycobacterium tuberculosis and Mycobacterium abscessus produce broad-spectrum class A ß-lactamases, BlaC and Bla Mab , which are inhibited by clavulanate and avibactam, respectively. BlaC differs from Bla Mab at Ambler position 132 in the conserved motif SDN (SDG versus SDN, respectively). Here, we investigated whether this polymorphism could account for the inhibition specificity of ß-lactamases from slowly and rapidly growing mycobacteria. Methods: Enzyme kinetics were determined to assess the impact of the substitutions G 132 N in BlaC and N 132 G in Bla Mab on ß-lactamase inhibition by clavulanate and avibactam. The stability of acylenzymes was evaluated by MS. The impact of the substitutions on the antibacterial activity of drug combinations was determined based on production of the ß-lactamases in Escherichia coli . Results: The substitution G 132 N increased 140-fold the efficacy of BlaC inhibition by avibactam and abolished clavulanate inhibition due to acylenzyme hydrolysis. Bla Mab efficiently hydrolysed clavulanate, but the substitution N 132 G led to a 5600-fold reduction in the hydrolysis rate constant k cat due to stabilization of Bla Mab -clavulanate covalent adducts. The N 132 G substitution also led to a 610-fold reduction in the efficacy of Bla Mab carbamylation by avibactam. Testing resistance to the amoxicillin/clavulanate and amoxicillin/avibactam combinations revealed that modifications in the catalytic properties of the ß-lactamases resulted in opposite shifts from susceptibility to resistance and vice versa. Conclusions: G 132 N and N 132 G had opposite effects on the inhibition of BlaC and Bla Mab , indicating that these substitutions might lead to acquisition of resistance to either of the ß-lactamase inhibitors, but not to both of them.

Inhibition by Avibactam and Clavulanate of the ß-Lactamases KPC-2 and CTX-M-15 Harboring the Substitution N132G in the Conserved SDN Motif.

The substitution N132G in the SDN motif of class A ß-lactamases from rapidly growing mycobacteria was previously shown to impair their inhibition by avibactam but to improve the stability of acyl-enzymes formed with clavulanate. The same substitution was introduced in KPC-2 and CTX-M-15 to assess its impact on ß-lactamases from Enterobacteriaceae and evaluate whether it may lead to resistance to the ceftazidime-avibactam combination. Kinetic parameters for the inhibition of the ß-lactamases by avibactam and clavulanate were determined by spectrophotometry using nitrocefin as the substrate. The substitution N132G impaired (>1,000-fold) the efficacy of carbamylation of KPC-2 and CTX-M-15 by avibactam. The substitution improved the inhibition of KPC-2 by clavulanate due to reduced deacylation, whereas the presence or absence of N132G resulted in the inhibition of CTX-M-15 by clavulanate. The hydrolysis of amoxicillin and nitrocefin by KPC-2 and CTX-M-15 was moderately affected by the substitution N132G, but that of ceftazidime, ceftaroline, and aztreonam was drastically reduced. Isogenic strains producing KPC-2 and CTX-M-15 were constructed to assess the impact of the substitution N132G on the antibacterial activities of ß-lactam-inhibitor combinations. For amoxicillin, the substitution resulted in resistance and susceptibility for avibactam and clavulanate, respectively. For ceftazidime, ceftaroline, and aztreonam, the negative impact of the substitution on ß-lactamase activity prevented resistance to the ß-lactam-avibactam combinations. In conclusion, the N132G substitution has profound effects on the substrate and inhibition profiles of class A ß-lactamases, which are largely conserved in distantly related enzymes. Fortunately, the substitution does not lead to resistance to the ceftazidime-avibactam combination.