Characteristics and incidence of infections in patients with multiple myeloma treated by bispecific antibodies: a national retrospective study.

OBJECTIVES: Bispecific antibodies (BsAbs) are an effective treatment used in relapsed or refractory multiple myeloma. Despite a well-tolerated safety profile, infectious events appear to be frequent in clinical trials. Real-world data on epidemiology, characteristics, risk factors, and outcomes of infections in patients treated with BsAb are still needed. METHODS: A retrospective, multicentre study in BsAb-treated patients with multiple myeloma was performed in 14 French centres from December 2020 to February 2023. The primary objective was to describe the incidence of infections that required hospitalization, specific treatment, or adaptation in BsAb administration. RESULTS: Among 229 patients with multiple myeloma treated with BsAb, 153 (67%) received teclistamab, 47 (20%) received elranatamab, and 29 (13%) talquetamab. We reported a total of 234 infections, including 123 (53%) of grade of ≥3. Predominant infections affected the respiratory tract (n = 116, 50%) followed by bacteraemias (n = 36, 15%). The hospitalization rate was 56% (n = 131), and 20 (9%) infections resulted in death. Global cumulative incidence of the first infection was 70% in all patients, 73% in patients treated with B-cell maturation antigen-targeting, and 51% with GPRC5D-targeting BsAb. In univariate analyses, corticosteroids for cytokine release syndrome (CRS)/immune effector cell-associated neurotoxicity syndrome (ICANS) were associated with a higher risk of first infection (HR = 2.13; 95% CI, 1.38-3.28), whereas GPRC5D-targeting BsAb and anti-bacterial prophylaxis were associated with a lower risk (HR = 0.53; 95% CI, 0.3-0.94 and HR = 0.65; 95% CI, 0.46-0.9). Fine and Gray multivariate model found that only corticosteroids for CRS/ICANS were correlated with a higher risk of first infection (HR = 2.01; 95% CI, 1.27-3.19). DISCUSSIONS: The implementation of preventive measures that aim to mitigate the risk of infection under BsAb is pivotal, notably in patients who received corticosteroids for CRS/ICANS.

Practical checklist for implementation of antifungal stewardship programmes.

Introduction. Antifungal stewardship programmes are needed in healthcare facilities to limit the overuse or misuse of antifungals, which are responsible for an increase in antifungal resistance.Hypothesis/Gap Statement. Core recommendations for antifungal stewardship were published by the Mycoses Study Group Education and Research Consortium, while the Centers for Disease Control and Prevention (CDC) provided a Core Elements of Hospital Antibiotic Stewardship Programs checklist. The recommendations offer global core elements for best practices in antifungal stewardship, but do not provide a framework for the implementation of antifungal stewardship programmes in healthcare facilities.Aim. In line with the recommendations, it is of the utmost importance to establish a practical checklist that may be used to implement antifungal stewardship programmes.Methodology. The practical checklist was established by a national consensus panel of experts involved in antifungal stewardship activities. A preliminary checklist was sent to all experts. The final document was approved by the panel after discussion and the resolution of any disagreements by consensus.Results. The final checklist includes the following items: leadership support; actions to support optimal antifungal use; actions to monitor antifungal prescribing, use and resistance; and an education programme.Conclusion. This antifungal stewardship checklist offers opportunities for antifungal resistance containment, given that antifungal stewardship activities promote the optimal use of antifungals.

Does 18F-FDG PET/CT add value to conventional imaging in clinical assessment of chronic disseminated candidiasis?

Background: Chronic disseminated candidiasis (CDC) classically occurs after profound and prolonged neutropenia. The aim of the CANHPARI study was to assess the clinical value of adding 18F-fluorodeoxyglucose PET/CT to conventional radiology for initial and subsequent evaluations of CDC. Materials and methods: A pilot prospective study was conducted in 23 French onco-hematological centers from 2013 to 2017 (NCT01916057). Patients ≥ 18 y.o. suspected for CDC on abdominal conventional imaging (CT or MRI) were included. PET/CT and conventional imaging were performed at baseline and month 3 (M3). Follow-up was assessed until M12. The primary outcome measure was the global response at M3, i.e., apyrexia and complete response to PET/CT. The secondary outcome measure consists in comparison between responses to PET/CT and conventional imaging at diagnosis and M3. Results: Among 52 included patients, 44 were evaluable (20 probable and 24 possible CDC); 86% had acute leukemia, 55% were male (median age 47 years). At diagnosis, 34% had fever and conventional imaging was always abnormal with microabscesses on liver and spleen in 66%, liver in 25%, spleen in 9%. Baseline PET/CT showed metabolic uptake on liver and/or spleen in 84% but did not match with lesion localizations on conventional imaging in 32%. M3 PET/CT showed no metabolic uptake in 13 (34%) patients, 11 still having pathological conventional imaging. Global response at M3 was observed in eight patients. Conclusion: Baseline PET/CT does not replace conventional imaging for initial staging of CDC lesions but should be performed after 3 months of antifungal therapy. Clinical trial registration: [www.clinicaltrials.gov], identifier [NCT01916057].

The Management of a Comprehensive Cancer Center during the First Six Months of the COVID-19 Pandemic in the South of France: Lessons from the Paoli-Calmettes Institute's Experience.

During the COVID-19 pandemic, it was rapidly established that cancer patients have an increased risk of developing severe forms of the 2019 coronavirus disease (COVID-19) due to a backlog of cancer diagnostics and immunosuppressive treatments. Cancer centers had to quickly adapt to continue cancer therapies despite the high infection risks and major disruptions in the French healthcare system. We described and analyzed the impact of the pandemic in our institution: management adjustments, COVID-19 infection rates in patients and staff, and impacts on clinical activities and finances during the first wave of the pandemic from March to September 2020. We also compared the results to the clinical activity data from preceding periods. A crisis unit was rapidly created that met 27 times over 66 days, generating numerous changes in hospital protocol. While our area was devastated by the pandemic, the infection rate of our staff and patients remained low (less than 1.5% of all employees). However, the lockdown period was accompanied with a reduction of most clinical activities, leading to decreases of 43%, 36%, 36%, 1%, and 10% in surgery, endoscopy, radiotherapy, and in- and out-patient chemotherapy sessions, respectively, with substantial financial loss. Our report highlights the need for the rapid creation, implementation, and adaptation of new protocols during a pandemic's evolution to prevent disease transmission. Lessons from this situation should provide motivation to better prepare for/limit the dismantling of cancer therapies that can dramatically impact patient care and have deleterious consequences on an institution's financial situation.

Post-intensive care syndrome: Screening and management in primary care.

BACKGROUND: Post-intensive care syndrome (PICS) affects as many as 50% of intensive care unit (ICU) survivors, and symptoms can persist for months to years. When psychological symptoms are experienced by patients' loved ones, this is termed PICS-family (PICS-F). Patients with these syndromes represent a frequently underrecognised and suboptimally managed cohort. OBJECTIVE: The aim of this article is to outline the key aspects of screening and primary care management, providing an evidence-based framework for general practitioners (GPs). DISCUSSION: PICS screening is not well defined. The breadth of symptoms, along with the absence of a national consensus, renders in-depth assessment a significant undertaking. Community management relies on a coordinated effort from the whole multidisciplinary team, spearheaded by the GP, and focuses on three key areas: 'information and education', 'assessment and therapy' and 'personal support'. Collaboration between key stakeholders is needed to improve outcomes in this hitherto underrecognised patient population.

Post-intensive care syndrome: A crash course for general practice.

BACKGROUND: Post-intensive care syndrome (PICS) refers to a constellation of cognitive, psychiatric and physical symptoms experienced by patients during and following a period of critical illness. As many as 50% of intensive care unit (ICU) survivors are affected, and symptoms can persist for months to years. When psychological symptoms are experienced by patients' loved ones, this is termed PICS-family (PICS-F). OBJECTIVE: The aim of this article is to summarise the key facets of PICS and PICS-F with a focus on incidence and pathophysiology.  DISCUSSION: The amalgam of symptoms in PICS has a profound impact on the quality of life of affected ICU survivors. The number of patients with PICS is expected to rise considerably as a result of the COVID-19 pandemic. Primary care practitioners are ideally situated to assist in early diagnosis and treatment.

A prospective, observational study of fidaxomicin use for Clostridioides difficile infection in France.

OBJECTIVE: To describe the characteristics, management and outcomes of hospitalised patients with Clostridioides difficile infection (CDI) treated with and without fidaxomicin. METHODS: This prospective, multicentre, observational study (DAFNE) enrolled hospitalised patients with CDI, including 294 patients treated with fidaxomicin (outcomes recorded over a 3-month period) and 150 patients treated with other CDI therapies during three 1-month periods. The primary endpoint was baseline and CDI characteristics of fidaxomicin-treated patients. RESULTS: At baseline, the fidaxomicin-treated population included immunocompromised patients (39.1%) and patients with severe (59.2%) and recurrent (36.4%) CDI. Fidaxomicin was associated with a high rate of clinical cure (92.2%) and low CDI recurrence (16.3% within 3 months). Clinical cure rates were ≥90% in patients aged ≥65 years, those receiving concomitant antibiotics and those with prior or severe CDI. There were 121/296 (40.9%) patients with adverse events (AEs), 5.4% with fidaxomicin-related AEs and 1.0% with serious fidaxomicin-related AEs. No fidaxomicin-related deaths were reported. CONCLUSIONS: Fidaxomicin is an effective and well-tolerated CDI treatment in a real-world setting in France, which included patients at high risk of adverse outcomes.Trial registration: Description of the use of fidaxomicin in hospitalised patients with documented Clostridium difficile infection and the management of these patients (DAFNE), NCT02214771, www.ClinicalTrials.gov.

Saprochaete clavata Outbreak Infecting Cancer Center through Dishwasher.

Saprochaete clavata is a pathogenic yeast responsible for rare outbreaks involving immunocompromised patients, especially those with hematologic malignancies. During February 2016-December 2017, we diagnosed S. clavata infections in 9 patients (8 with fungemia), including 3 within 1 month, at a cancer center in Marseille, France. The patients (median age 58 years), 4 of 9 of whom had acute myeloid leukemia, were hospitalized in 3 different wards. Ten environmental samples, including from 2 dishwashers and 4 pitchers, grew S. clavata, but no contaminated food was discovered. The outbreak ended after contaminated utensils and appliances were discarded. Whole-genome sequencing analysis demonstrated that all clinical and environmental isolates belonged to the same phylogenetic clade, which was unrelated to clades from previous S. clavata outbreaks in France. We identified a dishwasher with a deficient heating system as the vector of contamination.

De-escalation of antimicrobial treatment in neutropenic patients with severe sepsis: results from an observational study.

BACKGROUND: In severe sepsis, guidelines recommend de-escalating the empirical antimicrobial treatment as soon as the microbiological results are available. We aimed to determine the rate of de-escalation of the empirical antimicrobial treatment in neutropenic patients with severe sepsis. The characteristics of antimicrobial treatment associated with de-escalation and its impact on short- and long-term survival were also determined. METHODS: In the intensive care unit (ICU) of a cancer referral center, we prospectively collected observational data related to the antimicrobial management in neutropenic patients who developed severe sepsis and were admitted to ICU for at least 48 h. De-escalation of antimicrobial therapy consisted either of deleting one of the empirical antibiotics of a combined treatment, or, whenever possible, to use a betalactam antibiotic with a narrower spectrum of activity. Multivariate logistic regression was conducted to determine the factors associated with de-escalation, while a Cox proportional hazards model with a time-dependent covariate was fitted to assess the effect of de-escalation on 30-day survival. Finally 1-year survival after ICU discharge was compared across de-escalation groups. RESULTS: Cumulative incidence of de-escalation of the empirical antimicrobial treatment among the 101 patients of the cohort was 44%, [95% confidence interval (CI) 38-53%], including 30 (68%) patients with ongoing neutropenia. A microbiological documentation was available in 63 (63%) patients. Factors associated with de-escalation were the adequation of the empirical antimicrobial treatment in ICU [OR = 10.8 (95% CI 1.20-96)] for adequate documented treatment versus appropriate empirical treatment, the compliance with guidelines regarding the empirical choice of the anti-pseudomonal betalactam [OR = 10.8 (95% CI 1.3-89.5)]. De-escalation did not significantly modify the hazard of death within the first 30 days [HR = 0.51 (95% CI 0.20-1.33)], nor within 1 year after ICU discharge [HR = 1.06 (95% CI 0.54-2.08)]. CONCLUSION: Our data suggest that, in ICU, de-escalation of the empirical antimicrobial treatment is frequently applied in neutropenic cancer patients with severe sepsis. No evidence of any prognostic impact of this de-escalation was found.

Impact of pretransplant donor and recipient cytomegalovirus serostatus on outcome for multiple myeloma patients undergoing reduced intensity conditioning allogeneic stem cell transplantation.

Scope of the study was to investigate the impact of pre-transplant CMV serostatus of the donor and/or recipient on the outcome of patients undergoing allogeneic hematopoietic stem cell transplantation (Allo-SCT) for Multiple Myeloma (MM). To our knowledge no data are available in the literature about this issue. We retrospectively followed 99 consecutive patients who underwent reduced-intensity conditioning (RIC) Allo-SCT for MM in our cancer center at Marseille between January 2000 and January 2012. Based upon CMV serostatus, patients were classified as low risk (donor [D]-/recipient [R] -) 17 patients (17.1%), intermediate risk (D+/R) 14 patients (14.1%), or high risk - either (D-/R+) 31 patients (31.3%) or (D+/R+), 37 patients (37.3%). Cumulative incidence of CMV reactivation was 39% with a median time of 61 days (26-318). Three patients (3%) developed CMV disease. Two factors were associated with CMV reactivation: CMV serostatus group (low: 0% vs. intermediate: 29% vs. high: 50%; p=0.001) and the presence of grade II-IV acute GvHD (Hazard Ratio: HR=2.1 [1.1-3.9]). Thirty-six of the 39 patients (92%) with CMV reactivation did not present positive detection of CMV after a 21-day median duration preemptive treatment with ganciclovir. Cumulative incidence of day 100 grade II-IV acute GvHD, 1-year chronic GvHD and day 100 transplantation related mortality (TRM) were 37%, 36% and 9%, respectively. CMV reactivation and serostatus were not associated with increased GvHD and TRM or short survival. Only the presence of acute GvHD as a time dependent variable was significantly associated with increased TRM (p=0.005). Two-year overall and progression free survival were 56% and 34%, respectively. Donor and recipient CMV serostatus and acute GvHD are independent factors for increased CMV reactivation in high-risk MM patients undergoing RIC Allo-SCT. However, we did not find any influence of CMV reactivation on post transplantation outcome. CMV monitoring and pre-emptive treatment strategy could in part explain these results. Novel prophylactic measures such as immunotherapy and drug prophylaxis need to be considered in this group of patients, warranting further prospective studies.

JC Virus Leuko-Encephalopathy in Reduced Intensity Conditioning Cord Blood Transplant Recipient with a Review of the Literature.

We report here the case of progressive multifocal leukoencephalopathy (PML) related to human polyomavirus JC (JCV) infection after an allogeneic transplantation with umbilical cord blood cells in 59-year-old woman with follicular Non Hodgkin lymphoma. She presented with dysphagia and weakness; magnetic resonance imaging demonstrated marked signal abnormality in the sub-cortical white matter of the left frontal lobe and in the posterior limb of the right internal capsule. Polymerase chain reaction (PCR) analysis of the cerebrospinal fluid (CSF) was positive for John Cunningham (JC) virus. JC viral DNA in the CSF was positive, establishing the diagnosis of PML. Brain biopsy was not done. Extensive investigations for other viral infections seen in immuno-compromised patients were negative. The patient's neurologic deficits rapidly increased throughout her hospital stay, and she died one month after the diagnosis. These findings could have practical implications and demonstrate that in patients presenting neurological symptoms and radiological signs after UCBT, the JCV encephalitis must be early suspected.

D-Ala-d-Ser VanN-type transferable vancomycin resistance in Enterococcus faecium.

Enterococcus faecium UCN71, isolated from a blood culture, was resistant to low levels of vancomycin (MIC, 16 µg/ml) but susceptible to teicoplanin (MIC, 0.5 µg/ml). No amplification was observed with primers specific for the previously described glycopeptide resistance ligase genes, but a PCR product corresponding to a gene called vanN was obtained using degenerate primers and was sequenced. The deduced VanN protein was related (65% identity) to the d-alanine:d-serine VanL ligase. The organization of the vanN gene cluster, determined using degenerate primers and by thermal asymmetric interlaced (TAIL)-PCR, was similar to that of the vanC operons. A single promoter upstream from the resistance operon was identified by rapid amplification of cDNA ends (RACE)-PCR. The presence of peptidoglycan precursors ending in d-serine and d,d-peptidase activities in the absence of vancomycin indicated constitutive expression of the resistance operon. VanN-type resistance was transferable by conjugation to E. faecium. This is the first report of transferable d-Ala-d-Ser-type resistance in E. faecium.

Algorithm based on CMV kinetics DNA viral load for preemptive therapy initiation after hematopoietic cell transplantation.

Preemptive therapy in hematopoietic cell transplantation is initiated by a diagnostic technique at first detection of cytomegalovirus (CMV). The aim of this study was to use the viral dynamics of CMV DNA viral to start preemptive therapy, and to prospectively compare the CMV viral load kinetics to pp65 antigenemia. Two hundred sixty-three blood samples were collected prospectively from 93 patients. All clinical decisions regarding use of preemptive therapy were based on CMV antigenemia. Based on the positivity of the antigen assay and clinical CMV outcome in allotransplant patients, an optimal threshold of 3.05 log 10 (1,130 copies/ml) was found to discriminate patients who required preemptive therapy and those who did not (sensitivity, 71%; specificity, 65%). A DNAemia level increase of 2.24 log 10 (174 copies/ml) per day was the optimal threshold to discriminate between patients who required preemptive therapy and those who did not (sensitivity, 93%; specificity, 43%). Sensitivity of PCR assay was 92.4% compared with 39% for the antigen assay (P < 0.001). A standardized real-time PCR assay is more appropriate than the antigen assay for detecting CMV. It allowed earlier diagnosis of active CMV infection and monitoring of the response to anti-CMV treatment.

Once-weekly liposomal amphotericin B for prophylaxis of invasive fungal infection after graft-versus-host disease in allogeneic hematopoietic stem cell transplantation: a comparative retrospective single-center study.

BACKGROUND AND OBJECTIVES: The liposomal formulation of amphotericin B (LAmB) has been shown to cause few and mild infusion-related reactions, while achieving high plasma and tissue concentrations compared with conventional amphotericin B. We investigated the efficacy and safety of high-dose LAmB (7.5 mg/kg once weekly) prophylaxis of fungal infections in allogeneic stem-cell transplanted (allo-SCT) patients with graft-versus-host disease (GvHD). DESIGN AND SETTING: Retrospective, comparative, single-center. METHODS: Forty-two patients receiving high-dose prednisone for GvHD after allo-SCT had LAmB prophylaxis; 83 patients in the control group received other antifungal prophylaxis. RESULTS: In the LAmB prophylaxis group, the median duration of treatment was 7 weeks. The cumulative incidence of invasive fungal infection was 8% at 1 year after transplantation, 8% at 2 years and 16% at 3 years in the LAmB group vs. 36% at 1 year, 44% at 2 years and 49% at 3 years in the other prophylaxis group (P=.008). Fungal infection-related mortality after transplantation was observed in none of the patients in the LAmB prophylaxis group vs. 12 patients (14%) at 1 year, 14 patients (17%) at 2 years and 16 patients (19%) at 3 years in the control group (P=.005). The tolerance of the treatment was good with only 5 patients (12%) having a reversible nephrotoxicity leading to temporary treatment discontinuation. CONCLUSIONS: High-dose LAmB prophylaxis seems effective and well tolerated in this short series of allo-SCT patients with GvHD. Prospective clinical studies are required to confirm these results.

Noninvasive assessment of cardiac index in healthy volunteers: a comparison between thoracic impedance cardiography and Doppler echocardiography.

BACKGROUND: Thoracic bioimpedance cardiography (ICG) has been proposed as a noninvasive, continuous, operator-independent, and cost-effective method for cardiac output monitoring. In the present study, we compared cardiac index (CI) measurements with ICG (Niccomo device) and transthoracic Doppler echocardiography in resting healthy volunteers undergoing hemodynamic load challenge. METHODS: Twenty-five healthy volunteers (7 men and 18 women, mean age 36 +/- 6 yr, body surface area 1.75 +/- 0.17 m(2)) were investigated during three experimental conditions: baseline, positive end-expiratory pressure + 10 cm H(2)O and lower body positive pressure by means of medical antishock trousers inflated to 30 cm H(2)O in the abdominal compartment. RESULTS: ICG signal quality was >89% over all sets of measurements. A weak but significant relationship was observed between CI(TTE) and CI(ICG) (r = 0.36; P = 0.002). Agreement between both techniques was 0.94 L x min(-1) x m(-2) (95% CI: 0.77-1.11), limits of agreement were -0.47 to 2.35 L x min(-1) x m(-2), and percentage error was 53%. No statistically significant relationships were found between percent changes in CI(TTE) and CI(ICG) after applications of positive end-expiratory pressure + 10 cm H(2)O (r = 0.21; P = 0.31) and medical antishock trousers (r = 0.22; P = 0.30). CONCLUSIONS: Poor correlation and lack of agreement between absolute values of CI measured by ICG and transthoracic Doppler echocardiography were found in resting healthy volunteers. The Niccomo device was also unreliable for monitoring changes in CI during hemodynamic load challenge.

High prevalence of fastidious bacteria in 1520 cases of uveitis of unknown etiology.

The etiologic evaluation of uveitis is frequently unsuccessful when noninvasive methods are used. We conducted a prospective study to evaluate systematic screening for pathogens of uveitis. All patients with uveitis referred to the participating tertiary ophthalmology departments from January 2001 to September 2007 underwent intraocular and serum specimen collection. The standardized protocol for laboratory investigations included universal polymerase chain reaction (PCR)-based detection of any bacteria and mycoses, specific PCR-based detection of fastidious (difficult-to-grow) bacteria and herpes viruses, and culture of vitreous fluid. Sera were tested for fastidious bacteria. Among the 1321 included patients (1520 specimens), infection was diagnosed in 147 (11.1%) patients: 78 (53%) were caused by fastidious bacteria that included spirochetes, Bartonella species, intracellular bacteria (Chlamydia species, Rickettsia species, Coxiella burnetii), and Tropheryma whipplei; 18 by herpes viruses; and 9 by fungi. Bartonella quintana, Coxiella burnetii, Paracoccus yeei, Aspergillus oryzae, and Cryptococcus albidus were found to be associated with uveitis for the first time, to our knowledge. We recommend applying a 1-step diagnostic procedure that incorporates intraocular, specific microbial PCR with serum analyses in tertiary centers to determine the etiology of uveitis.

Ameba-associated microorganisms and diagnosis of nosocomial pneumonia.

To elucidate the role of ameba-associated microorganisms (AAMs) as etiologic agents of pneumonia, we screened for Legionella spp., Parachlamydia acanthamoeba, Afipia sp., Bosea spp., Bradyrhizobium spp., Mesorhizobium amorphae, Rasbo bacterium, Azorhizobium caulinodans, Acanthamoeba polyphaga mimivirus, and conventional microorganisms in 210 pneumonia patients in intensive-care units by using culture, polymerase chain reaction, and serologic testing. These resulted in 59 diagnoses in 40 patients. AAMs and non-AAMs were implicated in 10.5% of the patients. The infectious agents were identified in 15 patients: Acanthamoeba polyphaga mimivirus, 8; Legionella pneumophila, 3; L. anisa, 1; Parachlamydia sp., 1; Bosea massiliensis, L. worsleiensis, L. quinlivanii, and L. rubrilucens, 1; and M. amorphae and R. bacterium, 1. A. polyphaga mimivirus was the fourth most common etiologic agent, with a higher seroprevalence than noted in healthy controls. This finding suggested its clinical relevance. Therefore, AAM might cause nosocomial pneumonia and should be suspected when conventional microbiologic results are negative.

rpoB gene sequence-based characterization of emerging non-tuberculous mycobacteria with descriptions of Mycobacterium bolletii sp. nov., Mycobacterium phocaicum sp. nov. and Mycobacterium aubagnense sp. nov.

Over the past 10 years, 16S rRNA gene sequencing has contributed to the establishment of more than 45 novel species of non-tuberculous mycobacteria and to the description of emerging mycobacterial infections. Cumulative experience has indicated that this molecular tool underestimates the diversity of this group and does not distinguish between all recognized mycobacterial taxa. In order to improve the recognition of emerging rapidly growing mycobacteria (RGM), rpoB gene sequencing has been developed. Our previous studies have shown that an RGM isolate is a member of a novel species if it exhibits >3 % sequence divergence in the rpoB gene from the type strains of established species. When applied to a collection of 59 clinical RGM isolates, rpoB gene sequencing revealed nine novel isolates (15.3 %) whereas only two isolates (3.4 %) were deemed to be novel by conventional 16S rRNA gene sequence analysis. A polyphasic approach, including biochemical tests, antimicrobial susceptibility analyses, hsp65, sodA and recA gene sequence analysis, DNA G+C content determination and cell-wall fatty acid composition analysis, supported the evidence that these nine isolates represent three novel species. Whereas Mycobacterium phocaicum sp. nov. (type strain N4T = CIP 108542T = CCUG 50185T) and Mycobacterium aubagnense sp. nov. (type strain U8T = CIP 108543T = CCUG 50186T; Mycobacterium mucogenicum group) were susceptible to most antibiotics, Mycobacterium bolletii sp. nov. (type strain BD(T) = CIP 108541T = CCUG 50184T; Mycobacterium chelonae-abscessus group) was resistant to the quinolones, tetracycline, macrolides and imipenem. Only M. bolletii was resistant to clarithromycin. These data illustrate that rpoB gene sequence-based identification is a powerful tool to characterize emerging RGM and mycobacterial infections and provides valuable help in differentiating RGM at both the intra- and interspecies level, thus contributing to a faster and more efficient diagnosis and epidemiological follow-up.