Is the term “anti-anaerobic” still relevant?

International audienceFor decades, the term "anti-anaerobic" has been commonly used to refer to antibiotics exhibiting activity against anaerobic bacteria, also designated as anaerobes. This term is used in various situations ranging from infections associated with well-identified pathogens like Clostridioides difficile, or Fusobacterium necrophorum in Lemierre's syndrome, that require specific antibiotic treatments to polymicrobial infections generally resulting from the decreased permeability of anatomical barriers (e.g., intestinal translocation and stercoral peritonitis) or infectious secondary localizations (e.g., brain abscess and infectious pleurisy). In these cases, the causal bacteria generally remain unidentified and the antimicrobial treatment is empirical. However, major progress in the knowledge of human bacterial microbiotas in the last 10 years has shown how diverse are the species involved in these communities. Here, we sought to reappraise the concept of anti-anaerobic spectrum in the light of recent advances in the microbiota field. We first highlight that the term anaerobic itself does not represent the tremendous diversity of the bacteria it spans, and then we stress that the antibiotic susceptibility profiles for most anaerobic bacteria remain unaddressed. Furthermore, we provide examples challenging the relevance of the "anti-anaerobic" spectrum from a clinical and ecological perspective

Overly broad-spectrum antibiotic treatment of wild-type <i>Pseudomonas aeruginosa</i> 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 β-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

Blood Cultures for the Diagnosis of Infective Endocarditis: What Is the Benefit of Prolonged Incubation?

To assess the need for prolonged incubation of blood culture bottles beyond five days for the diagnosis of infectious endocarditis (IE), we conducted a retrospective cohort study of 6109 sets of two blood culture bottles involving 1211 patients admitted to the Henri Mondor University Hospital for suspicion of IE between 1 January 2016 and 31 December 2019. Among the 322 patients with IE, 194 had positive blood cultures in our centre. Only one patient with a time-to-positivity blood culture of more than 120 h (5 days) was found. The main cause for the 22 patients with positive blood cultures after five days was contamination with Cutibacterium acnes. Our results do not support extending the duration of incubation of blood culture bottles beyond five days for the diagnosis of infectious endocarditis, with the exception of patients with risk factors for C. acnes infection

Clinical relevance and antimicrobial susceptibility profile of the unknown human pathogen Corynebacterium aurimucosum

International audienceIntroduction. Even though Corynebacterium aurimucosum has been described in 2002, this species has long been underestimated due to the unreliability of conventional identification methods and only a few cases of infections have been reported. Hypothesis/Gap Statement. Little is known about clinical significance and antimicrobial susceptibility profile of this uncommon species. Aim. To evaluate the clinical relevance of C. aurimucosum and its antimicrobial susceptibility profile. Methodology. All C. aurimucosum isolates, collected from 2010 to 2019 in 10 French university hospitals, were retrospectively included. Demographic, clinical and microbiological data were collected for all cases. Antimicrobial susceptibility testing was performed according to the 2019 EUCAST guidelines. Results. Fifty--seven clinical isolates of C. aurimucosum were collected in 57 patients (median age, 65.8 years; male/female sex ratio, 1.1), mostly from urine (28%), blood culture (28 %) and bone/synovial fluid (19 %) samples. Of them, 14 cases of infection were confirmed, mainly bone and joint infections (50%) followed by urinary tract infections (UTIs) (21%), bacteremia (14 %), skin and soft--tissue infections (14%). C. aurimucosum was recovered in pure culture in 36% of cases (UTIs and bacteremia) while mixed cultures were observed for other infections. By testing 52 clinical isolates in vitro, this species appeared to be fully susceptible to linezolid and vancomycin while most isolates (&gt;80%) were susceptible to amoxicillin (MIC90, 2 mu g ml(-1)), gentamicin, tetracycline and rifampicin. Both cefotaxime and ciprofloxacin seemed to have a limited activity (ca. 50% of susceptible strains). The MIC distribution for ciprofloxacin showed a bimodal profile with a population of highly-resistant strains with MICs &gt;2 mu g ml(-1). Most isolates (&gt;90%) were categorized as resistant to penicillin G and clindamycin. Conclusion. C. aurimucosum should be considered as an actual opportunistic pathogen, and treatment with amoxicillin, vancomycin or linezolid should be preferred

Impact of a Dedicated Pretransplant Infectious Disease Consultation on Respiratory Tract Infections in Kidney Allograft Recipients: A Retrospective Study of 516 Recipients

Background: Respiratory tract infections (RTIs) are a leading cause of death after kidney transplant. Preventive strategies may be implemented during a dedicated infectious disease consultation (IDC) before transplantation. Impact of IDC on RTIs after transplant has not been determined. Methods: We conducted a monocentric retrospective cohort analysis including all kidney transplant recipients from January 2015 to December 2019. We evaluated the impact of IDC on RTIs and identified risk and protective factors associated with RTIs. Results: We included 516 kidney transplant recipients. Among these, 145 had an IDC before transplant. Ninety-five patients presented 123 RTIs, including 75 (61%) with pneumonia. Patient that benefited from IDC presented significantly less RTIs (p = 0.049). RTIs were an independent risk factor of mortality (HR = 3.64 (1.97–6.73)). Independent risk factors for RTIs included HIV (OR = 3.33 (1.43–7.74)) and HCV (OR = 3.76 (1.58–8.96)). IDC was identified as an independent protective factor (OR = 0.48 (0.26–0.88)). IDC prior to transplantation is associated with diminished RTIs and is an independent protective factor. RTIs after kidney transplant are an independent risk factor of death. Implementing systematic IDC may have an important impact on reducing RTIs and related morbidity and mortality

Epidemiology, Risk Factors, and Outcomes of Opportunistic Infections after Kidney Allograft Transplantation in the Era of Modern Immunosuppression: A Monocentric Cohort Study

Epidemiology of opportunistic infections (OI) after kidney allograft transplantation in the modern era of immunosuppression and the use of OI prevention strategies are poorly described. We retrospectively analyzed a single-center cohort on kidney allograft adult recipients transplanted between January 2008 and December 2013. The control group included all kidney recipients transplanted in the same period, but with no OI. We analyzed 538 kidney transplantations (538 patients). The proportion of OI was 15% (80 and 72 patients). OI occurred 12.8 (6.0&#8722;31.2) months after transplantation. Viruses were the leading cause (n = 54, (10%)), followed by fungal (n = 15 (3%)), parasitic (n = 6 (1%)), and bacterial (n = 5 (0.9%)) infections. Independent risk factors for OI were extended criteria donor (2.53 (1.48&#8722;4.31), p = 0.0007) and BK viremia (6.38 (3.62&#8722;11.23), p &lt; 0.0001). High blood lymphocyte count at the time of transplantation was an independent protective factor (0.60 (0.38&#8722;0.94), p = 0.026). OI was an independent risk factor for allograft loss (2.53 (1.29&#8722;4.95), p = 0.007) but not for patient survival. Post-kidney transplantation OIs were mostly viral and occurred beyond one year after transplantation. Pre-transplantation lymphopenia and extended criteria donor are independent risk factors for OI, unlike induction therapy, hence the need to adjust immunosuppressive regimens to such transplant candidates

Performance of commercial methods for linezolid susceptibility testing of Enterococcus faecium and Enterococcus faecalis

International audienceBackground - Linezolid-resistant enterococci (LRE) causing infections that are challenging to treat are rising, highlighting the need for reliable screening of LRE clinical isolates. Objectives - To evaluate the ability of the broth microdilution (BMD) method for LRE detection and to assess the performance of seven commercially available techniques for linezolid susceptibility testing. Methods - A collection of 100 clinical isolates (80 Enterococcus faecium and 20 Enterococcus faecalis), including 20 optrA-positive isolates, 17 poxtA-positive isolates and 1 optrA/poxtA-positive E. faecium isolate, were studied. MICs were determined after 18 h [Day 1 (D1)] and 42 h [Day 2 (D2)] of incubation and interpreted following EUCAST and CLSI guidelines, which currently provide different interpretative breakpoints. Performance of commercial techniques was compared with BMD results. Results - MIC50/D1 and MIC50/D2 were both 8 mg/L, while MIC90/D1 and MIC90/D2 were 16 and 32 mg/L, respectively. MICD1 values for poxtA-positive isolates were lower than those for optrA-positive isolates. Proportions of susceptible isolates at D1 and D2 were 48% and 41%, respectively, according to EUCAST breakpoints and 35% and 13%, respectively, according to CLSI criteria (the proportions of isolates categorized as intermediate following CLSI recommendations were 13% and 28% at D1 and D2, respectively). Percentage susceptibility assessed by the commercially available techniques was always higher. The four commercial methods allowing MIC determination provided an overall essential agreement of ≥90% at D1. Categorical agreement and error rates were generally improved at D2. Conclusions - Non-automated methods (Sensititre and UMIC) and, to a lesser extent, gradient strip Etest appear to show an acceptable correlation with the BMD reference method for the detection of isolates with low MICs of linezolid after prolonged incubation

Elective distribution of resistance to beta-lactams among Enterobacter cloacae genetic clusters

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Potential of Multiplex Polymerase Chain Reaction Performed on Protected Telescope Catheter Samples for Early Adaptation of Antimicrobial Therapy in ARDS Patients

Background: Diagnosis of co/superinfection in patients with Acute Respiratory Distress Syndrome (ARDS) is challenging. The FilmArray Pneumonia plus Panel (bioMérieux, France), a new rapid multiplex Polymerase Chain Reaction (mPCR), has never been assessed on a blinded protected telescope catheter (PTC) samples, a very common diagnostic tool in patients under mechanical ventilation. We evaluated the performance of mPCR on PTC samples compared with conventional culture and its impact on antibiotic stewardship. Methods: Observational study in two intensive care units, conducted between March and July 2020, during the first wave of the COVID-19 pandemic in France. Results: We performed 125 mPCR on blinded PTC samples of 95 ARDS patients, including 73 (77%) SARS-CoV-2 cases and 28 (29%) requiring extracorporeal membrane oxygenation. Respiratory samples were drawn from mechanically ventilated patients either just after intubation (n = 48; 38%) or later for suspected ventilator-associated pneumonia (VAP) (n = 77; 62%). The sensitivity, specificity, positive, and negative predictive values of mPCR were 93% (95% CI 84–100), 99% (95% CI 99–100), 68% (95% CI 54–83), and 100% (95% CI 100–100), respectively. The overall coefficient of agreement between mPCR and standard culture was 0.80 (95% CI 0.68–0.89). Intensivists changed empirical antimicrobial therapy in only 14% (18/125) of cases. No new antibiotic was initiated in more than half of the CAP/HAP pneumonia-suspected cases (n = 29; 60%) and in more than one-third of those suspected to have VAP without affecting or delaying their antimicrobial therapy. Conclusions: Rapid mPCR was feasible on blinded PTC with good sensitivity and specificity. New antibiotics were not initiated in more than half of patients and more than one-third of VAP-suspected cases. Further studies are needed to assess mPCR potential in improving antibiotic stewardship