Short-Course Versus Prolonged-Course Antimicrobial Therapy in Adults With Catheter-Related Septic Thrombosis: A Propensity-Weighted Retrospective Study.

Background: Optimal duration of antimicrobial therapy (AT) for catheter-related septic deep venous thrombosis (DVT) is unknown. We aimed to compare the outcomes of patients receiving short-course AT (≤21 days) versus prolonged-course AT (>21 days). Methods: This was a monocentric retrospective study comparing adults with catheter-related septic DVT from 2015 to 2020 treated with short- or prolonged-course AT. A propensity score-weighted analysis was used to mitigate potential bias. The primary outcome was a composite of all-cause mortality or recurrent bloodstream infection 30 days after AT discontinuation. Results: Of 172 patients with catheter-related septic DVT, 104 were treated with prolonged-course AT and 68 with short-course AT. In the propensity score analysis, we found no significant difference in 30-day all-cause mortality or relapse between the 2 groups (inverse probability of treatment weighted hazard ratio [wHR], 2.16 [95% confidence interval {CI}, .68-6.88]; P = .192). No differences in 90-day all-cause mortality and 90-day relapse were observed between the treatment groups (wHR, 1.01 [95% CI, .49-2.05], P = .987 and 1.13 [95% CI, .08-15.62], P = .928, respectively). Conclusions: A 21-day AT could be an effective and safe option to treat catheter-related septic DVT. Further randomized studies are needed to establish the optimal duration of AT for patients with catheter-related septic DVT.

Are Escherichia coli causing recurrent cystitis just ordinary Uropathogenic E. coli (UPEC) strains?

Specific determinants associated with Uropathogenic Escherichia coli (UPEC) causing recurrent cystitis are still poorly characterized. The aims of this study were (i) to describe genomic and phenotypic traits associated with recurrence using a large collection of recurrent and paired sporadic UPEC isolates, and (ii) to explore within-host genomic adaptation associated with recurrence using series of 2 to 5 sequential UPEC isolates. Whole genome comparative analyses between 24 recurrent cystitis isolates (RCIs) and 24 phylogenetically paired sporadic cystitis isolates (SCIs) suggested a lower prevalence of putative mobile genetic elements (MGE) in RCIs, such as plasmids and prophages. The intra-patient evolution of the 24 RCI series over time was characterized by SNP occurrence in genes involved in metabolism or membrane transport, and by plasmid loss in 5 out of the 24 RCI series. Genomic evolution occurred early in the course of recurrence, suggesting rapid adaptation to strong selection pressure in the urinary tract. However, RCIs did not exhibit specific virulence factor determinants and could not be distinguished from SCIs by their fitness, biofilm formation, or ability to invade HTB-9 bladder epithelial cells. Taken together, these results suggest a rapid but not convergent adaptation of RCIs that involves both strain- and host-specific characteristics.

Contribution of Antibiotic Susceptibility Testing and CH Typing Compared to Next-Generation Sequencing for the Diagnosis of Recurrent Urinary Tract Infections Due to Genetically Identical Escherichia coli Isolates: a Prospective Cohort Study of Cystitis in Women.

Recurrent cystitis is a common disease in women, mainly due to uropathogenic Escherichia coli (UPEC). For decades, typing methods now considered obsolete suggested that relapse by the same clone is dominant over reinfection, most UPEC strains being otherwise fully susceptible to antibiotics. We aimed to update these data. Thanks to a prospective study over 17 months, we recruited 323 women with cystitis. Of these, 251 of them had sporadic infection and 72 had recurrence, with 2 to 9 episodes per patient for a total of 131 UPEC isolates and 145 UPEC pairs at patient level. Phylogroups B2 (52.4%) and D (14.1%) were overall dominant, as expected due to their particular urovirulence. CH typing identified 119 distinct profiles with no CH type particularly associated with recurrence. Relapse was attested by CH typing for only 30.6% (22 out of 72), with very diverse situations ranging from all episodes due to the same clone to alternating reinfections and relapses. Next-generation sequencing confirmed the clonality for all but two of the 145 UPEC pairs. Antibiotic resistance was common for recurrent cystitis isolates (only 25 [17.2%] out of 145 UPEC pairs were fully susceptible), allowing us to predict UPEC clonality. Indeed, antibiotic susceptibility profile matched CH typing for 104 (71.7%) pairs. Finally, we demonstrated a large genetic diversity among UPEC isolates responsible for cystitis in women, even in cases of recurrence for which reinfection appeared dominant over relapse. Recurrent cystitis appears to be a heterogeneous disease requiring tailored treatment and prevention. IMPORTANCE More than half of women will experience cystitis during their lifetime. Among these women, 25% will experience a second episode within the following 6 months. It is epidemiologically important to discriminate relapses from reinfections. Relapse identification relies on long and laborious methods and might influence treatment. Therefore, the designation of time- and cost-effective strategies for this goal is of particular interest. Our work suggests using CH typing and antibiotic susceptibility profiles to type Escherichia coli, the main uropathogen.

Phenotypic and genotypic within-host diversity of Pseudomonas aeruginosa urinary isolates.

This study aimed to assess phenotypic and molecular inter-patient and within-host diversity of Pseudomonas aeruginosa isolates responsible for urinary tract infection (UTI) or asymptomatic bacteriuria (AB). Clinical data of 120 consecutive P. aeruginosa UTI (n = 40) and AB (n = 80) were prospectively analyzed. Up to five P. aeruginosa isolates per sample were collected. Antimicrobial susceptibility testing (AST) was determined for all isolates (n = 591); a subset of 358 was characterized by multilocus sequence typing. 444 isolates (75%) were non-multidrug resistant (MDR), 113 (19%) were MDR, and 34 (6%) were extensively drug resistant. A genetically highly diverse population was observed (64 sequence types [STs]), without strict correlation between genotypes and clinical settings. 35 patients (28%; 12 UTIs and 23 ABs) presented distinct antimicrobial resistance (AMR) profiles within a given urine sample, significantly associated with previous carbapenem and fluroquinolones exposure; five of them also exhibited polyclonal UTI or AB (with isolates belonging to two STs). P. aeruginosa urinary isolates of these 120 patients were highly diverse, in terms of AMR as well as genetic background. Both within-host AMR and molecular diversity can complicate AST, treatment and control of P. aeruginosa UTI.

Investigation of Coagulation Biomarkers to Assess Clinical Deterioration in SARS-CoV-2 Infection.

Since December 2019, a pandemic caused by a new coronavirus has spread to more than 170 countries around the world. Worsening infected patients requiring intensive care unit (ICU) admission associated with 30% of mortality. A part of worsening is induced by hemostasis deregulation. The aim of this study was to investigate the association of coagulation activation in COVID-19 progression. Thirty-five of the 99 patients got clinically worse. The final model of the logistic regression analysis revealed that O2 requirement (RR = 7.27 [1.50-19.31]), monocytes below 0.2G/L (RR = 2.88 [1.67-3.19]), fibrinogen levels (RR = 1.45 [1.17-1.82] per g/L increase), prothrombin fragments 1+2 higher than 290 pM (RR = 2.39 [1.20-3.30]), and thrombin peak (RR = 1.28 [1.03-1.59] per 50 nM increase) were associated with an increased risk of clinical worsening. A fibrinogen level threshold of 5.5 g/L, a thrombin peak measurement threshold of 99 pM, and O2 requirement associated with clinical outcome in more than 80% of our cohort. In conclusion, we identified fibrinogen and thrombin peak at admission as coagulation biomarkers associated with an increased risk of ICU admission or death. This finding allows initiating steroids and triage for worsening patients. Our results should therefore be considered as exploratory and deserve confirmation.

Cardiopulmonary Exercise Testing to Assess Persistent Symptoms at 6 Months in People With COVID-19 Who Survived Hospitalization: A Pilot Study.

OBJECTIVE: The aim of this pilot study was to assess physical fitness and its relationship with functional dyspnea in survivors of COVID-19 6 months after their discharge from the hospital. METHODS: Data collected routinely from people referred for cardiopulmonary exercise testing (CPET) following hospitalization for COVID-19 were retrospectively analyzed. Persistent dyspnea was assessed using the modified Medical Research Council dyspnea scale. RESULTS: Twenty-three people with persistent symptoms were referred for CPET. Mean modified Medical Research Council dyspnea score was 1 (SD = 1) and was significantly associated with peak oxygen uptake (VO2peak; %) (rho = -0.49). At 6 months, those hospitalized in the general ward had a relatively preserved VO2peak (87% [SD = 20]), whereas those who had been in the intensive care unit had a moderately reduced VO2peak (77% [SD = 15]). Of note, the results of the CPET revealed that, in all individuals, respiratory equivalents were high, power-to-weight ratios were low, and those who had been in the intensive care unit had a relatively low ventilatory efficiency (mean VE/VCO2 slope = 34 [SD = 5]). Analysis of each individual showed that none had a breathing reserve <15% or 11 L/min, all had a normal exercise electrocardiogram, and 4 had a heart rate >90%. CONCLUSION: At 6 months, persistent dyspnea was associated with reduced physical fitness. This study offers initial insights into the mid-term physical fitness of people who required hospitalization for COVID-19. It also provides novel pathophysiological clues about the underlaying mechanism of the physical limitations associated with persistent dyspnea. Those with persistent dyspnea should be offered a tailored rehabilitation intervention, which should probably include muscle reconditioning, breathing retraining, and perhaps respiratory muscle training. IMPACT: This study is the first, to our knowledge, to show that a persistent breathing disorder (in addition to muscle deconditioning) can explain persistent symptoms 6 months after hospitalization for COVID-19 infection and suggests that a specific rehabilitation intervention is warranted.

Assessment of Multiplex Digital Droplet RT-PCR as a Diagnostic Tool for SARS-CoV-2 Detection in Nasopharyngeal Swabs and Saliva Samples.

BACKGROUND: Reverse transcription-quantitative PCR on nasopharyngeal swabs is currently the reference COVID-19 diagnosis method but exhibits imperfect sensitivity. METHODS: We developed a multiplex reverse transcription-digital droplet PCR (RT-ddPCR) assay, targeting 6 SARS-CoV-2 genomic regions, and evaluated it on nasopharyngeal swabs and saliva samples collected from 130 COVID-19 positive or negative ambulatory individuals, who presented symptoms suggestive of mild or moderate SARS-CoV2 infection. RESULTS: For the nasopharyngeal swab samples, the results obtained using the 6-plex RT-ddPCR and RT-qPCR assays were all concordant. The 6-plex RT-ddPCR assay was more sensitive than RT-qPCR (85% versus 62%) on saliva samples from patients with positive nasopharyngeal swabs. CONCLUSION: Multiplex RT-ddPCR represents an alternative and complementary tool for the diagnosis of COVID-19, in particular to control RT-qPCR ambiguous results. It can also be applied to saliva for repetitive sampling and testing individuals for whom nasopharyngeal swabbing is not possible.

Efficacy of temocillin against MDR Enterobacterales: a retrospective cohort study.

OBJECTIVES: EUCAST recently advised against temocillin use, except for non-serious urinary tract infections (UTI) caused by Escherichia coli, Klebsiella spp. (except Klebsiella aerogenes) and Proteus mirabilis (EKP) treated with a dose of 2 g q8h. We aimed to analyse our practice in the context of a larger temocillin use in France. PATIENTS AND METHODS: All ≥3 day temocillin prescriptions from 2016 to 2019 were reviewed, with reference to French recommendations and a susceptibility breakpoint of 8 mg/L. The primary outcome was early clinical failure (antibiotic switch, relapse or death within 10 days after the completion of antibiotic treatment). RESULTS: Overall, 153 cases were analysed: 123 cases of UTI (80.4%) and 133 cases of monomicrobial infection with Enterobacterales (86.9%). A total of 160 Enterobacterales were isolated, comprising 108 (67.5%) ESBL producers and 30 (20.7%) non-EKP species. The rate of early clinical failure was 9.2% and was significantly lower for UTI compared with non-UTI (4.9% versus 26.7%, P = 0.001) and for sepsis compared with severe sepsis or septic shock (6.2% versus 25%, P = 0.011). It was not different between 2 g q12h and 2 g q8h doses (10% versus 7.4%, P = 0.81) and between EKP and other Enterobacterales (8.7% versus 14.3%, P = 0.41). CONCLUSIONS: EUCAST recommendations on urinary isolates seem to be too restrictive. Our data support the efficacy of temocillin at a dose of 2 g q12h to treat patients with non-severe complicated UTI caused by MDR Enterobacterales with an MIC of ≤8 mg/L, whatever the species.

Tolerance and Persistence of Pseudomonas aeruginosa in Biofilms Exposed to Antibiotics: Molecular Mechanisms, Antibiotic Strategies and Therapeutic Perspectives.

Pseudomonas aeruginosa biofilm-related infections are difficult to treat with antibiotics. Along the different layers of the biofilm, the P. aeruginosa population is heterogeneous, exhibiting an extreme ability to adapt his metabolic activity to the local microenvironment. At the deepest layers of the biofilm is a subset of dormant cells, called persister cells. Though antimicrobial failure might be multifactorial, it is now demonstrated that these persister cells, genetically identical to a fully susceptible strain, but phenotypically divergent, are highly tolerant to antibiotics, and contribute to antimicrobial failure. By eradicating susceptible, metabolically active cells, antibiotics bring out pre-existing persister cells. The biofilm mode of growth creates microenvironment conditions that activate stringent response mechanisms, SOS response and toxin-antitoxin systems that render the bacterial population highly tolerant to antibiotics. Using diverse, not standardized, models of biofilm infection, a large panel of antibiotic regimen has been evaluated. They demonstrated that biofilm growth had an unequal impact of antibiotic activity, colistin and meropenem being the less impacted antibiotics. Different combination and sequential antimicrobial therapies were also evaluated, and could be partially efficient, but none succeeded in eradicating persister cells, so that non-antibiotic alternative strategies are currently under development. This article reviews the molecular mechanisms involved in antibiotic tolerance and persistence in P. aeruginosa biofilm infections. A review of the antimicrobial regimen evaluated for the treatment of P. aeruginosa biofilm infection is also presented. While tremendous progress has been made in the understanding of biofilm-related infections, alternative non-antibiotic strategies are now urgently needed.

Efficacy of a ciprofloxacin/amikacin combination against planktonic and biofilm cultures of susceptible and low-level resistant Pseudomonas aeruginosa.

BACKGROUND: Eradicating bacterial biofilm without mechanical dispersion remains a challenge. Combination therapy has been suggested as a suitable strategy to eradicate biofilm. OBJECTIVES: To evaluate the efficacy of a ciprofloxacin/amikacin combination in a model of in vitro Pseudomonas aeruginosa biofilm. METHODS: The antibacterial activity of ciprofloxacin and amikacin (alone, in combination and successively) was evaluated by planktonic and biofilm time-kill assays against five P. aeruginosa strains: PAO1, a WT clinical strain and three clinical strains overexpressing the efflux pumps MexAB-OprM (AB), MexXY-OprM (XY) and MexCD-OprJ (CD), respectively. Amikacin MIC was 16 mg/L for XY and ciprofloxacin MIC was 0.5 mg/L for CD. The other strains were fully susceptible to ciprofloxacin and amikacin. The numbers of total and resistant cells were determined. RESULTS: In planktonic cultures, regrowth of high-level resistant mutants was observed when CD was exposed to ciprofloxacin alone and XY to amikacin alone. Eradication was obtained with ciprofloxacin or amikacin in the other strains, or with the combination in XY and CD strains. In biofilm, bactericidal reduction after 8 h followed by a mean 4 log10 cfu/mL plateau in all strains and for all regimens was noticed. No regrowth of resistant mutants was observed whatever the antibiotic regimen. The bacterial reduction obtained with a second antibiotic used simultaneously or consecutively was not significant. CONCLUSIONS: The ciprofloxacin/amikacin combination prevented the emergence of resistant mutants in low-level resistant strains in planktonic cultures. Biofilm persister cells were not eradicated, either with monotherapy or with the combination.

Temocillin breakpoints in pyelonephritis: evaluation in a murine model due to ESBL-producing Escherichia coli clinical isolates.

BACKGROUND: Due to a spectrum restricted to Enterobacteriaceae and stability against ESBL and AmpC enzymes, temocillin is of major interest for the treatment of pyelonephritis. But there are still uncertainties about the optimal regimen and clinical breakpoints. OBJECTIVES: To study in a murine model of pyelonephritis the activity of temocillin against Escherichia coli isolates with different MICs in order to evaluate clinical breakpoints. METHODS: Four clinical uropathogenic E. coli isolates with temocillin MICs of 8 mg/L (Ec8), 16 mg/L (Ec16), 32 mg/L (Ec32) and 64 mg/L (Ec64) were evaluated. Antibiotic 24 h T>MIC achieved in humans was reproduced in mice with either intravenous temocillin (2 g q12h or 2 g q8h) or intravenous imipenem (1 g q8h). Efficacy was assessed by bacterial count in kidneys. RESULTS: Compared with controls, temocillin at 2 g q12h was highly efficient against Ec8 (-3.32 log10 cfu/g and negative cultures in 93% of mice; P < 0.001); imipenem gave similar results. Temocillin at 2 g q12h also induced high reduction of bacterial count against Ec16 (-2.92 log10 cfu/g; P < 0.001), albeit cultures were negative in only 48% of mice. In contrast, no significant effect was observed in mice infected by Ec32 (-0.01 log10 cfu/g; P = 0.981) or Ec64 (-0.55 log10 cfu/g; P = 0.523). Even temocillin at 2 g q8h failed to control Ec32 infection (-1.55 log10 cfu/g; P = 0.197). CONCLUSIONS: This model suggests a clinical breakpoint up to 16 mg/L for non-severe pyelonephritis treated with temocillin at 2 g q12h, a value consistent with the few previous available data.

Pharmacokinetics and Pharmacodynamics of Temocillin.

Temocillin, a 6-α-methoxy derivative of ticarcillin, is a forgotten antibiotic that has recently been rediscovered, and issues about clinical breakpoints and optimal therapeutic regimens are still ongoing. Temocillin spectrum is almost restricted to Enterobacteriaceae. The addition of the α-methoxy moiety on ticarcillin confers resistance to hydrolysis by Ambler classes A and C ß-lactamases (extended spectrum ß-lactamases, Klebsiella pneumoniae carbapenemase and AmpC hyperproduced enzymes). Temocillin is bactericidal, and the effect of inoculum size on its activity is relatively mild. The proportion of spontaneous resistant mutants in vitro to temocillin is low, as found in vivo. After intravenous infusion, temocillin showed a prolonged elimination half-life of approximately 5 h. The percentage of protein binding of temocillin is high (approximately 80%), and is concentration-dependent. Temocillin clearance is mainly renal, and urinary recovery is high, ranging from 72 to 82% after 24 h. Furthermore, the penetration of temocillin into bile and peritoneal fluid is high, but poor into cerebrospinal fluid. The cumulative percentage of a 24-h period during which the free drug concentration exceeds the minimum inhibitory concentration (fT > MIC) at steady-state pharmacokinetic conditions seems to be the best pharmacokinetic/pharmacodynamic (PK/PD) index correlating with temocillin efficacy. An fT > MIC of 40-50% is associated with antibacterial effect and survival in vivo. Monte Carlo simulations performed in critically ill patients showed that the 2 g every 12 h and 2 g every 8 h regimens provide a 95% probability of target attainment of 40% fT > MIC up to an MIC of 8 mg/L. In less severely ill patients or in specific foci of infection, such as urinary tract infection, a 4 g daily regimen should be adequate for strains with temocillin MIC up to 16 mg/L. Data regarding actual wild-type MIC distribution, clinical efficacy, PK profiling in volunteers or patients, and PD targets are scarce, and further studies are required to support appropriate dosing recommendations and determination of clinical breakpoints.