CRP under 130 mg/L rules out the diagnosis of Legionella pneumophila serogroup 1 (URINELLA Study).

INTRODUCTION: In case of pneumonia, some biological findings are suggestive for Legionnaire's disease (LD) including C-reactive protein (CRP). A low level of CRP is predictive for negative Legionella Urinary-Antigen-Test (L-UAT). METHOD: Observational retrospective study in Nord-Franche-Comté Hospital with external validation in Besançon University Hospital, France which included all adults with L-UAT performed during January 2018 to December 2022. The objective was to determine CRP optimal threshold to predict a L-UAT negative result. RESULTS: URINELLA included 5051 patients (83 with positive L-UAT). CRP optimal threshold was 131.9 mg/L, with a negative predictive value (NPV) at 100%, sensitivity at 100% and specificity at 58.0%. The AUC of the ROC-Curve was at 88.7% (95% CI, 86.3-91.1). External validation in Besançon Hospital patients showed an AUC at 89.8% (95% CI, 85.5-94.1) and NPV, sensitivity and specificity was respectively 99.9%, 97.6% and 59.1% for a CRP threshold at 131.9 mg/L; after exclusion of immunosuppressed patients, index sensitivity and NPV reached also 100%. CONCLUSION: In case of pneumonia suspicion with a CRP level under 130 mg/L (independently of the severity) L-UAT is useless in immunocompetent patients with a NPV at 100%. We must remain cautious in patients with symptoms onset less than 48 h before CRP dosage.

Multicenter Retrospective Study of Vascular Infections and Endocarditis Caused by Campylobacter spp., France.

The incidence of campylobacteriosis has substantially increased over the past decade, notably in France. Secondary localizations complicating invasive infections are poorly described. We aimed to describe vascular infection or endocarditis caused by Campylobacter spp. We included 57 patients from a nationwide 5-year retrospective study on Campylobacter spp. bacteremia conducted in France; 44 patients had vascular infections, 12 had endocarditis, and 1 had both conditions. Campylobacter fetus was the most frequently involved species (83%). Antibiotic treatment involved a ß-lactam monotherapy (54%) or was combined with a fluoroquinolone or an aminoglycoside (44%). The mortality rate was 25%. Relapse occurred in 8% of cases and was associated with delayed initiation of an efficient antimicrobial therapy after the first symptoms, diabetes, and coexistence of an osteoarticular location. Cardiovascular Campylobacter spp. infections are associated with a high mortality rate. Systematically searching for those localizations in cases of C. fetus bacteremia may be warranted.

Retrospective Multicentric Study on Campylobacter spp. Bacteremia in France: The Campylobacteremia Study.

BACKGROUND: Campylobacter spp. bacteremia is a severe infection. A nationwide 5-year retrospective study was conducted to characterize its clinical features and prognostic factors. METHODS: The study included patients with Campylobacter spp. bacteremia diagnosed in 37 French hospitals participating in the surveillance network of the National Reference Center for Campylobacters and Helicobacters, from 1 January 2015 to 31 December 2019. The goal was to analyze the effects of a delay of appropriate antibiotic therapy and other risk factors on 30-day mortality rates, antibiotic resistance, patient characteristics, and prognosis according to the Campylobacter species. RESULTS: Among the 592 patients, Campylobacter jejuni and Campylobacter fetus were the most commonly identified species (in 42.9% and 42.6%, respectively). The patients were elderly (median age 68 years), and most had underlying conditions, mainly immunodepression (43.4%), hematologic cancers (25.9%), solid neoplasms (23%), and diabetes (22.3%). C. jejuni and Campylobacter coli were associated with gastrointestinal signs, and C. fetus was associated with secondary localizations. Among the 80 patients (13.5%) with secondary localizations, 12 had endocarditis, 38 vascular, 24 osteoarticular, and 9 ascitic fluid infections. The 30-day mortality rate was 11.7%, and an appropriate antibiotic treatment was independently associated with 30-day survival (odds ratio, 0.47 [95% confidence interval, .24-.93]; P = .03). The median efficient therapy initiation delay was quite short (2 days [interquartile range, 0-4 days]) but it had no significant impact on the 30-day mortality rate (P = .78). CONCLUSIONS: Campylobacter spp. bacteremia mainly occurred in elderly immunocompromised individuals with variable clinical presentations according to the species involved. Appropriate antimicrobial therapy was associated with improved 30-day survival.

Mechanisms of Resistance to Ceftolozane/Tazobactam in Pseudomonas aeruginosa: Results of the GERPA Multicenter Study.

Resistance mechanisms of Pseudomonas aeruginosa to ceftolozane/tazobactam (C/T) were assessed on a collection of 420 nonredundant strains nonsusceptible to ceftazidime (MIC > 8 µg/ml) and/or imipenem (>4 µg/ml), collected by 36 French hospital laboratories over a one-month period (the GERPA study). Rates of C/T resistance (MIC > 4/4 µg/ml) were equal to 10% in this population (42/420 strains), and 23.2% (26/112) among the isolates resistant to both ceftazidime and imipenem. A first group of 21 strains (50%) was found to harbor various extended-spectrum ß-lactamases (1 OXA-14; 2 OXA-19; 1 OXA-35; 1 GES-9; and 3 PER-1), carbapenemases (2 GES-5; 1 IMP-8; and 8 VIM-2), or both (1 VIM-2/OXA-35 and 1 VIM-4/SHV-2a). All the strains of this group belonged to widely distributed epidemic clones (ST111, ST175, CC235, ST244, ST348, and ST654), and were highly resistant to almost all the antibiotics tested except colistin. A second group was composed of 16 (38%) isolates moderately resistant to C/T (MICs from 8/4 to 16/4 µg/ml), of which 7 were related to international clones (ST111, ST253, CC274, ST352, and ST386). As demonstrated by targeted mass spectrometry, cloxacillin-based inhibition tests, and gene blaPDC deletion experiments, this resistance phenotype was correlated with an extremely high production of cephalosporinase PDC. In part accounting for this strong PDC upregulation, genomic analyses revealed the presence of mutations in the regulator AmpR (D135N/G in 6 strains) and enzymes of the peptidoglycan recycling pathway, such as AmpD, PBP4, and Mpl (9 strains). Finally, all of the 5 (12%) remaining C/T-resistant strains (group 3) appeared to encode PDC variants with mutations known to improve the hydrolytic activity of the ß-lactamase toward ceftazidime and C/T (F147L, ΔL223-Y226, E247K, and N373I). Collectively, our results highlight the importance of both intrinsic and transferable mechanisms in C/T-resistant P. aeruginosa Which mutational events lead some clinical strains to massively produce the natural cephalosporinase PDC remains incompletely understood.

Performance of disc diffusion, MIC gradient tests and Vitek 2 for ceftolozane/tazobactam and ceftazidime/avibactam susceptibility testing of Pseudomonas aeruginosa.

OBJECTIVES: To assess performance of disc diffusion, gradient tests and Vitek 2 system to determine the susceptibility of clinical Pseudomonas aeruginosa strains to ceftolozane/tazobactam (C/T) and ceftazidime/avibactam (CZA). METHODS: Two-hundred non-duplicate P. aeruginosa strains isolated by 47 French medical laboratories were selected to cover a wide range of C/T and CZA MICs. Performance of C/T disc (30/10 µg, Bio-Rad), CZA discs (10/4 µg) (Thermo Fisher and Bio-Rad), C/T and CZA gradient tests (Etest, BioMérieux; MIC Test Strip, Liofilchem), and AST-XN12 card of Vitek 2 system (BioMérieux) were compared with a broth microdilution (BMD) method (Thermo Fisher). MIC and disc results were interpreted using current EUCAST breakpoints. RESULTS: Twenty percent and 17% of strains were resistant to C/T and CZA, respectively. All the methods tested satisfactorily determined the susceptibility of P. aeruginosa to C/T [Category Agreement (CA) ≥95%] except the disc diffusion method. Because of the high rates of Major Errors (MEs) (12.5%), this latter method tends to overestimate the resistance. For CZA, only the gradient tests yielded more than 90% of CA. The Vitek 2 system and disc diffusion misclassified 18.1%, 10.1% (disc Bio-Rad) and 11.9% (disc Thermo Fisher) of susceptible strains, respectively. CONCLUSIONS: The gradient tests (MIC Test Strip and Etest) and Vitek 2 card XN12 performed the best to determine the susceptibility of P. aeruginosa to C/T, whereas gradient tests were an acceptable alternative to BMD to assess CZA susceptibility.

Evaluation of the Immunochromatographic NG-Test Carba 5 for Rapid Identification of Carbapenemase in Nonfermenters.

The immunochromatographic assay NG-Test Carba 5 (NG-Biotech) was evaluated with a collection of 107 carbapenemase-producing nonfermenters (CP-NF) (55 Pseudomonas spp., 51 Acinetobacter spp., and 1 Achromobacter xylosoxidans isolate) and 61 carbapenemase-negative isolates. All KPC, VIM, and NDM carbapenemase producers tested were accurately detected. Of the 16 IMP variants tested, 6 (37.5%) variants were not detected. Considering the epidemiology of CP-NFs in France, the NG-Test Carba 5 would detect 89.4% of CP Pseudomonas spp. but only 12.9% of CP Acinetobacter spp.

Acquisition of class C ß-lactamase PAC-1 by ST664 strains of Pseudomonas aeruginosa.

Four ST664 (serotype O:5) strains of Pseudomonas aeruginosa highly resistant to antibiotics including ceftolozane/tazobactam and ceftazidime/avibactam but susceptible to colistin, were found to harbor the rare class C ß-lactamase PAC-1 encoding gene on a chromosomally-located Tn1721-like transposon. Gene bla PAC-1 was associated with the 16S rRNA methylase determinant rmtF2, that confers pan-aminoglycoside resistance. These genotypically-related strains were isolated in repatriated patients from Mauricius and Afghanistan and close to a lineage reported in Nepal, Pakistan and India.

Clonal dissemination of Pseudomonas aeruginosa isolates producing extended-spectrum ß-lactamase SHV-2a.

From January to December 2011, 24 Pseudomonas aeruginosa strains producing the extended-spectrum ß-lactamase SHV-2a were identified in 13 hospitals in France. With one exception, all the strains belonged to the same clone. Double-disk synergy tests with cefepime and clavulanate were able to detect all the SHV-2a-positive isolates.

A convenient method to screen for carbapenemase-producing Pseudomonas aeruginosa.

A combined-disk method using imipenem and cloxacillin was evaluated to discriminate between carbapenemase-producing (n = 56) and nonproducing (n = 62) strains of Pseudomonas aeruginosa. With a cloxacillin load of 4,000 µg/disk, this very simple method showed a sensitivity and a specificity of 100%, irrespective of the type of carbapenemase produced.

Complexity of resistance mechanisms to imipenem in intensive care unit strains of Pseudomonas aeruginosa.

BACKGROUND: Pseudomonas aeruginosa can become resistant to carbapenems by both intrinsic (mutation-driven) and transferable (ß-lactamase-based) mechanisms. Knowledge of the prevalence of these various mechanisms is important in intensive care units (ICUs) in order to define optimal prevention and therapeutic strategies. METHODS: A total of 109 imipenem-non-susceptible (MIC >4 mg/L) strains of P. aeruginosa were collected in June 2010 from the ICUs of 26 French public hospitals. Their resistance mechanisms were characterized by phenotypic, enzymatic, western blotting and molecular methods. RESULTS: Single or associated imipenem resistance mechanisms were identified among the 109 strains. Seven isolates (6.4%) were found to produce a metallo-ß-lactamase (one VIM-1, four VIM-2, one VIM-4 and one IMP-29). Porin OprD was lost in 94 (86.2%) strains as a result of mutations or gene disruption by various insertion sequences (ISPa1635, ISPa1328, IS911, ISPs1, IS51, IS222 and ISPa41). Thirteen other strains were shown to be regulatory mutants in which down-regulation of oprD was coupled with overexpressed efflux pumps CzcCBA (n = 1), MexXY (n = 9) and MexEF-OprN (n = 3). The lack of OprD was due to disruption of the oprD promoter by ISPsy2 in one strain and alteration of the porin signal sequence in another. CONCLUSIONS: Imipenem resistance in ICU P. aeruginosa strains may result from multiple mechanisms involving metallo-ß-lactamase gene acquisition and genetic events (mutations and ISs) inactivating oprD, turning down its expression while increasing efflux activities or preventing insertion of porin OprD in the outer membrane. This diversity of mechanisms allows P. aeruginosa, more than any other nosocomial pathogen, to rapidly adapt to carbapenems in ICUs.

Performance of the Disc Diffusion Method, MTS Gradient Tests and Two Commercially Available Microdilution Tests for the Determination of Cefiderocol Susceptibility in Acinetobacter spp.

Cefiderocol is a siderophore-conjugated cephalosporin with potent activity against multidrug-resistant Gram-negative pathogens including Acinetobacter baumannii. The aim of this study was to evaluate cefiderocol testing methods on a relevant collection of 97 Acinetobacter spp. isolates. Commercialized broth microdilution methods (ComASP®, Liofilchem and UMIC®, Bruker), MIC test strips (Liofilchem) and disc diffusion using discs of three different brands (Mast Diagnostic, Liofilchem and Oxoid-Thermo Fisher Scientific) were compared with the broth microdilution reference method. None of the methods tested fulfilled acceptable criteria (essential agreement [EA] ≥ 90%; bias = ±30%) but both BMD methods achieved acceptable categorical agreement rates (CA = 95.9% [93/97, 95% CI 89.9-98.4] and CA = 93.8% [91/97, 95% CI 87.2-97.1] for ComASP® and UMIC®, respectively) and bias < 30% (-7.2% and -25.2% for ComASP® and UMIC®, respectively). The use of MIC gradient testing is strongly discouraged due to misclassification of 55% (n = 23/42) of resistant strains. Finally, the disc diffusion method could be used to rapidly screen for susceptible strains by setting a critical diameter of 22 mm.

Performance of discs, sensititre EUMDROXF microplates and MTS gradient strips for the determination of the susceptibility of multidrug-resistant Pseudomonas aeruginosa to cefiderocol.

OBJECTIVES: To evaluate the performance of commercially available tests to determine the susceptibility of multidrug-resistant (MDR) clinical Pseudomonas aeruginosa strains to cefiderocol. METHODS: A collection of 150 clinical strains of P. aeruginosa resistant to ceftazidime, (MIC, Minimal Inhibitory Concentration, MIC > 8 mg/L) imipenem (MIC> 4 mg/L) and ceftolozane/tazobactam (MIC> 4/4 mg/L), isolated from 2015 to 2022 was selected. Cefiderocol susceptibility was determined in parallel (a) by disc diffusion using Mast, Oxoid and Liofilchem discs deposited on Mueller-Hinton agar batches from Bio-Rad, BioMérieux, Mast, Becton Dickinson, I2A and Oxoid; (b) by MIC gradient test strips (MTS) (Liofilchem); and (c) by EUMDROXF Sensititre microplates. MICs and inhibition zones were compared with the broth microdilution reference method (BMD) MICs. RESULTS: The MIC50 and MIC90 of cefiderocol were 1 mg/L and 8 mg/L by BMD, respectively, including 21.3% (32/150) resistant strains. None of the methods tested fulfilled acceptable criteria (essential agreement [EA] ≥ 90%; bias = ± 30%). Although the Sensititre EUMDROXF microplates overestimated MIC values (categorical agreement [CA] = 86.7% [130/150, 95% CI 80.3-91.2]; EA = 69.3% [104/150, 95% CI 61.6-76.2]; bias = 68.2%), MTS strips underestimated the MIC values for many strains (CA = 86.7%, 130/150, 95% CI 80.3-91.2; EA = 69.3%, 104/150, 95% CI 61.6-76.2; bias = -30.4%), classifying properly only 50% (16/32) of resistant strains. Finally, many cefiderocol-resistant strains were not identified by the disc method, although the CA ranged from 78.0% (117/150, 95% CI 70.7-83.0) to 89.3% (134/150, 95% IC 83.4-93.3) according to Mueller-Hinton agar batches. CONCLUSION: Determination of cefiderocol susceptibility in MDR P. aeruginosa clinical strains by Sensititre EUMDROXF microplates is an alternative to the reference BMD method. However, MIC values ± 1 dilution apart from the breakpoint (2 mg/L) should be controlled by BMD whereas the use of MTS gradient strips is discouraged. Disc diffusion might be useful for screening, unfortunately many cefiderocol-resistant strains are not detected.

Extracorporeal Membrane Oxygenation Cannula-Related Infections: Epidemiology and Risk Factors.

Although being a potential major source of infection in extracorporeal membrane oxygenation (ECMO) patients, data regarding cannula-related infections (CRI) remain scarce. We therefore aimed at describing the epidemiology of CRI among critically ill patients supported by ECMO. Between October 2017 and November 2019, adult patients supported by either venoarterial (VA), venopulmonary arterial, or venovenous (VV) ECMO for more than 24 hours were prospectively enrolled. When CRI was suspected, cannula swab and subcutaneous needle aspirate samples were obtained for microbiological culture. Cannula tips were systematically sent for culture at the time of ECMO removal. Primary end-point was CRI, which was defined by sepsis or local sign of cannula infection and at least one positive culture among swab, subcutaneous needle aspirate or tip. Multivariate analysis was performed to identify risk factors of CRI. Hundred patients were included, including 77 VA, 12 venopulmonary arterial, and 11 VV ECMO. Cannula-related infections were diagnosed after a median duration of ECMO of 10 [7-13] days. Rate of CRI was 24%, including 10% with bacteremia. Most frequent involved pathogens were Enterobacteriaceae (n = 14), Enterococci (n = 8), and coagulase-negative Staphylococci (n = 7). By multivariate analysis, diabetes and ECMO duration were independently associated with CRI.

Antimicrobial Resistance in Enterobacterales Recovered from Urinary Tract Infections in France.

In the context of increasing antimicrobial resistance in Enterobacterales, the management of these UTIs has become challenging. We retrospectively assess the prevalence of antimicrobial resistance in Enterobacterales isolates recovered from urinary tract samples in France, between 1 September 2017, to 31 August 2018. Twenty-six French clinical laboratories provided the susceptibility of 134,162 Enterobacterales isolates to 17 antimicrobials. The most frequent species were E. coli (72.0%), Klebsiella pneumoniae (9.7%), Proteus mirabilis (5.8%), and Enterobacter cloacae complex (2.9%). The overall rate of ESBL-producing Enterobacterales was 6.7%, and ranged from 1.0% in P. mirabilis to 19.5% in K. pneumoniae, and from 3.1% in outpatients to 13.6% in long-term care facilities. Overall, 4.1%, 9.3% and 10.5% of the isolates were resistant to cefoxitin, temocillin and pivmecillinam. Cotrimoxazole was the less active compound with 23.4% resistance. Conversely, 4.4%, 12.9%, and 14.3% of the strains were resistant to fosfomycin, nitrofurantoin, and ciprofloxacin. However, less than 1% of E. coli was resistant to fosfomycin and nitrofurantoin. We identified several trends in antibiotics resistances among Enterobacterales isolates recovered from the urinary tract samples in France. Carbapenem-sparing drugs, such as temocillin, mecillinam, fosfomycin, cefoxitin, and nitrofurantoin, remained highly active, including towards ESBL-E.

Temocillin susceptibility among Enterobacterales strains recovered from blood culture in France.

Temocillin is used for several years in some European countries but, only since 2015 in France. We assessed the susceptibility of Enterobacterales strains isolated from blood culture 1 year before (2014) and 2 years after (2017) its use in France. 1,387 strains were included by 17 clinical laboratories located throughout France: 363 in 2014 and 1,024 in 2017. The rate of resistance to temocillin was 4.6% and 26.7% in 3rd generation cephalosporin (3GC) susceptible and resistant strains respectively. Cephalosporinase-overproducer (COPE) strains were significantly more resistant to temocillin (37.7%) than ESBL-producer (ESBL-PE) (23.5%) (P < 0.01). The rate of temocillin resistance was correlated to the number of inactive beta-lactams. The rate of resistance to temocillin trend to increase from 13.9% in 2014 to 23.9% in 2017 (P < 0.01). Temocillin remains highly active against Enterobacterales but the trend in resistance should be assessed over time.

Meridional flow in the Sun's convection zone is a single cell in each hemisphere.

The Sun's magnetic field is generated by subsurface motions of the convecting plasma. The latitude at which the magnetic field emerges through the solar surface (as sunspots) drifts toward the equator over the course of the 11-year solar cycle. We use helioseismology to infer the meridional flow (in the latitudinal and radial directions) over two solar cycles covering 1996-2019. Two data sources are used, which agree during their overlap period of 2001-2011. The time-averaged meridional flow is shown to be a single cell in each hemisphere, carrying plasma toward the equator at the base of the convection zone with a speed of ~4 meters per second at 45° latitude. Our results support the flux-transport dynamo model, which explains the drift of sunspot-emergence latitudes through the meridional flow.