Bacteremia due to Lachnoanaerobaculum umeaense in a patient with acute myeloid leukemia during chemotherapy: A case report, and a review of the literature.

The present case reports a bacteremia due to Lachnoanaerobaculum umeaense (a Gram-positive, filamentous, rod-shaped, anaerobic, spore-forming bacillus present in the human oral microbiota) in a patient treated for acute myeloid leukemia. After failed identification by MALDI-TOF, identification was done by sequencing of 16s rRNA. The patient was successfully treated with Amoxicillin-clavulanic acid and ciprofloxacin for seven days. Comparison of V1-V3 regions of the bacterial 16S rRNA gene gene with published sequences failed to classify the strain as pathogenic or non-pathogenic based on this phylogenetic classification alone. Although Lachnoanaerobaculum gingivalis are known to be associated with bacteremia in patients with acute myeloid leukemia, this clinical case of infection by L. umeaense argues for further studies that will lead to more efficient classification of the infection by these microorganisms.

Clinical, Bacteriological, and Genetic Characterization of Bone and Joint Infections Involving Linezolid-Resistant Staphylococcus epidermidis: a Retrospective Multicenter Study in French Reference Centers.

The choice of the best probabilistic postoperative antibiotics in bone and joint infections (BJIs) is still challenging. Since the implementation of protocolized postoperative linezolid in six French referral centers, linezolid-resistant multidrug-resistant Staphylococcus epidermidis (LR-MDRSE) strains were isolated in patients with BJI. We aimed here to describe clinical, microbiological, and molecular patterns associated with these strains. All patients with at least one intraoperative specimen positive for LR-MDRSE between 2015 and 2020 were included in this retrospective multicenter study. Clinical presentation, management, and outcome were described. LR-MDRSE strains were investigated by MIC determination for linezolid and other anti-MRSA antibiotics, characterization of genetic determinants of resistance, and phylogenetic analysis. Forty-six patients (colonization n = 10, infection n = 36) were included in five centers, 45 had prior exposure to linezolid, 33 had foreign devices. Clinical success was achieved for 26/36 patients. Incidence of LR-MDRSE increased over the study period. One hundred percent of the strains were resistant to oxazolidinones, gentamicin, clindamycin, ofloxacin, rifampicin, ceftaroline, and ceftobiprole, and susceptible to cyclins, daptomycin, and dalbavancin. Susceptibility to delafloxacin was bimodal. Molecular analysis was performed for 44 strains, and the main mutation conferring linezolid resistance was the 23S rRNA G2576T mutation. All strains belonged to the sequence type ST2 or its clonal complex, and phylogenetic analysis showed emergence of five populations corresponding geographically to the centers. We showed the emergence of new clonal populations of highly linezolid-resistant S. epidermidis in BJIs. Identifying patients at risk for LR-MDRSE acquisition and proposing alternatives to systematic postoperative linezolid use are essential. IMPORTANCE The manuscript describes the emergence of clonal linezolid-resistant strains of Staphylococcus epidermidis (LR-MDRSE) isolated from patients presenting with bone and joint infections. Incidence of LR-MDRSE increased over the study period. All strains were highly resistant to oxazolidinones, gentamicin, clindamycin, ofloxacin, rifampicin, ceftaroline, and ceftobiprole, but were susceptible to cyclins, daptomycin, and dalbavancin. Susceptibility to delafloxacin was bimodal. The main mutation conferring linezolid resistance was the 23S rRNA G2576T mutation. All strains belonged to the sequence type ST2 or its clonal complex, and phylogenetic analysis showed emergence of five populations corresponding geographically to the centers. LR-MDRSE bone and joint infections seem to be accompanied by an overall poor prognosis related to comorbidities and therapeutic issues. Identifying patients at risk for LR-MDRSE acquisition and proposing alternatives to systematic postoperative linezolid use become essential, with a preference for parenteral drugs such as lipopeptids or lipoglycopeptids.

K1 Antigen Is Associated with Different AST Profile in Escherichia coli: A One-Month-Long Pilot Study.

Escherichia coli is responsible for diseases of varying severity. The "K" antigen designates the capsular polysaccharides on the bacterial surface, which are mostly similar to those of highly pathogenic bacteria. The K1 antigen is often found in pathogenic E. coli. Aim: While the published studies on the AST profile of K1-positive E. coli have focused on pregnant women or newborns, this study aimed to characterize the AST profile of K1-positive E. coli independently of the clinical sample of isolation. Over a 4-week-long period, all patients hospitalized/consulting at the Poitiers University Hospital presenting a determined AST on E. coli were prospectively included to define their K1-status (Pastorex Meningitis) and to collect the clinical (age/sex) or biological metadata (AST/MIC). Among the 296 included samples, no differential representation was observed between K1 results regarding sample nature. K1-negative results were associated with multiple antibiotic-resistance (12.3% vs. 33.0%; p < 0.01). AST phenotypes differed between these groups, with a higher proportion of K1-negativity among resistant strains, especially on ß-lactams (ureidopenicillin, 25.8% vs. 14.9%; and ampicillin/inhibitor, 50.0% vs. 26.8%; p < 0.05) or quinolone (19.8% vs. 7.0%) and sulfamethoxazole-trimethoprim (30.2% vs. 12.3%) (p < 0.01). This study analyzed E. coli ASTs in clinical samples of all types, regarding their K1-antigen status.

Assessment of a Multiplex Serological Test for the Diagnosis of Prosthetic Joint Infection: a Prospective Multicentre Study.

Introduction: The diagnosis of prosthetic joint infections (PJIs) can be difficult in the chronic stage and is based on clinical and paraclinical evidence. A minimally invasive serological test against the main pathogens encountered during PJI would distinguish PJI from mechanical loosening. Methods: We performed a prospective, multicentre, cross-sectional study to assess the contribution of serology in the diagnosis of PJI. Over a 2-year period, all patients undergoing prosthesis revision were included in the study. A C-reactive protein assay and a serological test specifically designed against 5 bacterial species (Staphylococcus aureus, S. epidermidis, S. lugdunensis, Streptococcus agalactiae, Cutibacterium acnes) were performed preoperatively. Five samples per patient were taken intraoperatively during surgery. The diagnosis of PJI was based on clinical and bacteriological criteria according to guidelines. Results: Between November 2015 and November 2017, 115 patients were included, 49 for a chronic PJI and 66 for a mechanical problem. Among patients with PJI, a sinus tract was observed in 32.6% and a C-reactive protein level ≥10 mg/L in 74.5%. The PJI was monomicrobial in 43 cases (targeted staphylococci, 24; S. agalactiae, 1; C. acnes, 2; others, 16), and polymicrobial in 6 cases (12.2%). Sensitivity, specificity, positive predictive value and negative predictive value were 75.0%, 82.1%, 58.3% and 90.8%, respectively, for targeted staphylococci. Specificity/negative predictive value was 97.3%/100% for S. agalactiae and 83.8% /96.9% for C. acnes. Conclusions: The serological tests are insufficient to affirm the diagnosis of PJI for the targeted bacteria. Nevertheless, the excellent NPV may help clinicians to exclude PJI.

Proficiency of PCR in hospital settings for nonculture diagnosis of invasive meningococcal infections.

BACKGROUND: Meningococcal meningitis requires rapid diagnosis and immediate management which is enhanced by the use of PCR for the ascertainment of these infections. However, its use is still restricted to reference laboratories. METHODS: We conducted an inter-laboratory study to assess the implementation and the performance of PCR in ten French hospital settings in 2010. RESULTS: Our data are in favour of this implementation. Although good performance was obtained in identifying Neisseria meningitidis positive samples, the main issue was reported in identifying other species (Streptococcus pneumoniae and Haemophilus influenzae) which are also involved in bacterial meningitis cases. CONCLUSIONS: Several recommendations are required and, mainly, PCR should target the major etiological agents (N. meningitidis, S. pneumonia, and H. influenzae) of acute bacterial meningitis. Moreover, PCR should predict the most frequent serogroups of Neisseria meningitidis according to local epidemiology.