Distribution of Achromobacter Species in 12 French Cystic Fibrosis Centers in 2020 by a Retrospective MALDI-TOF MS Spectrum Analysis.

Achromobacter spp. are nonfermenting Gram-negative bacilli mainly studied among cystic fibrosis (CF) patients. The identification of the 19 species within the genus is time-consuming (nrdA-sequencing), thus data concerning the distribution of the species are limited to specific studies. Recently, we built a database using MALDI-TOF mass spectrometry (MS) (Bruker) that allows rapid and accurate species identification and detection of the multiresistant epidemic clones: A. xylosoxidans ST137 spreading among CF patients in various French and Belgium centers, and A. ruhlandii DES in Denmark. Here, we first assessed whether species identification could be achieved with our database solely by analysis of MS spectra without availability of isolates. Then, we conducted a multicentric study describing the distribution of Achromobacter species and of the clone ST137 among French CF centers. We collected and analyzed with our local database the spectra of Achromobacter isolates from 193 patients (528 samples) from 12 centers during 2020. In total, our approach enabled to conclude for 502/528 samples (95.1%), corresponding to 181 patients. Eleven species were detected, only five being involved in chronic colonization, A. xylosoxidans (86.4%), A. insuavis (9.1%), A. mucicolens (2.3%), A. marplatensis (1.1%) and A. genogroup 3 (1.1%). This study confirmed the high prevalence of A. xylosoxidans in chronic colonizations and the circulation of the clone A. xylosoxidans ST137 in France: four patients in two centers. The present study is the first to report the distribution of Achromobacter species from CF patients samples using retrospective MALDI-TOF/MS data. This easy approach could enable future large-scale epidemiological studies.

Identification and Clinical Significance of Helcococcus kunzii in Human Samples.

From 2008 to 2013, 39 Helcococcus kunzii strains were collected from human clinical specimens (79% from foot ulcers), and 85% of the 39 patients were infected. Matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry and molecular methods accurately identified all isolates. This large study of clinical observations confirms the potential pathogenic role of H. kunzii.

Mycobacterium genavense Infections in Immunocompromised Patients Without HIV: Case Series of Solid Organ Transplant Patients and Literature Review.

Background: Mycobacterium genavense infection is rare and can occur in immunocompromised patients without human immunodeficiency virus (HIV). Methods: We describe 2 cases of M genavense infection in solid organ transplant (SOT) recipients, and we performed a literature review of immunocompromised patients without HIV. Results: Fifty-two cases are reported. Predisposing factors were receipt of SOT (40.4%) and autoimmune disease (36.5%). Infection was disseminated in 86.5% of cases. Organs involved were lymph nodes (72.3%), gastrointestinal tract (56.5%), lung (35.5%), and bone marrow (28.8%). Most patients were treated with at least 3 antimycobacterial agents (98%), with a clinical cure achieved in 54.9%. In multivariate analysis, lack for cure was associated with age of the time infection (odds ratio [OR], 15.81 [95% confidence interval {CI}, 2.92-152.93]; P = .011) and positive bone marrow culture (OR, 1.05 [95% CI, 1.01-1.12]; P = .042). Conclusions: Mycobacterium genavense infection is a rare and generally disseminated disease with a poor prognosis. Optimal treatment regimen and its duration remain to be defined.

High mortality in peritonitis due to Mycobacterium avium complex: retrospective study and systematic literature review.

BACKGROUND: Mycobacterium avium complex (MAC) infection is often disseminated and mainly involves lymph nodes, spleen, liver or bone marrow. Peritonitis due to MAC infection (PMAC) is a very uncommon manifestation. METHODS: In this report, after describing the case of the only PMAC infection in our 10-year retrospective study, which occurred in an AIDS patient who was non-adherent to highly active antiretroviral therapy (HAART), we performed a systematic literature review of documented bacteriological PMAC. RESULTS: Including our patient, 51 cases of PMAC have been reported. Patients were most often male (sex ratio 2.14), with a median age of 41 years (2.8-72) and an immunodeficiency in all cases, most often AIDS (57%), cirrhosis (20%) and continuous ambulatory peritoneal dialysis (CAPD) (18%). Ascites was more often chylous (54%) than exudative (46%) and, in this case, lymphocytic (60%), with an inconstantly positive acid-fast bacilli smear (54%). Non-disseminated PMAC patients were more likely to have peritoneal dialysis (39% versus 6.5%, p < .01) or cancer with immunosuppressive therapy (39% versus 0%, p < .0001), while AIDS was the leading underlying disease in disseminated-PMAC patients (83% versus 11%, p < .001). Mortality was high (50%), with no difference between disseminated and non-disseminated PMAC. CONCLUSIONS: This report highlights the need to be aware of an atypical presentation of PMAC infection, which is associated with a high rate of mortality even for non-disseminated infection.

Differences in potential for selection of clindamycin-resistant mutants between inducible erm(A) and erm(C) Staphylococcus aureus genes.

In staphylococci, inducible macrolide-lincosamide-streptogramin B (MLS(B)) resistance is conferred by the erm(C) or erm(A) gene. This phenotype is characterized by the erythromycin-clindamycin "D-zone" test. Although clindamycin appears active in vitro, exposure of MLS(B)-inducible Staphylococcus aureus to this antibiotic may result in the selection of clindamycin-resistant mutants, either in vitro or in vivo. We have compared the frequencies of mutation to clindamycin resistance for 28 isolates of S. aureus inducibly resistant to erythromycin and bearing the erm(C) (n = 18) or erm(A) (n = 10) gene. Seven isolates susceptible to erythromycin or bearing the msr(A) gene (efflux) were used as controls. The frequencies of mutation to clindamycin resistance for the erm(A) isolates (mean +/- standard deviation, 3.4 x 10(-8) +/- 2.4 x 10(-8)) were only slightly higher than those for the controls (1.1 x 10(-8) +/- 6.4 x 10(-9)). By contrast, erm(C) isolates displayed a mean frequency of mutation to clindamycin resistance (4.7 x 10(-7) +/- 5.5 x 10(-7)) 14-fold higher than that of the S. aureus isolates with erm(A). The difference was also observed, although to a lower extent, when erm(C) and erm(A) were cloned into S. aureus RN4220. We conclude that erm(C) and erm(A) have different genetic potentials for selection of clindamycin-resistant mutants. By the disk diffusion method, erm(C) and erm(A) isolates could be distinguished on the basis of high- and low-level resistance to oleandomycin, respectively.

Femoral vs jugular venous catheterization and risk of nosocomial events in adults requiring acute renal replacement therapy: a randomized controlled trial.

CONTEXT: Based on concerns about the risk of infection, the jugular site is often preferred over the femoral site for short-term dialysis vascular access. OBJECTIVE: To determine whether jugular catheterization decreases the risk of nosocomial complications compared with femoral catheterization. DESIGN, SETTING, AND PATIENTS: A concealed, randomized, multicenter, evaluator-blinded, parallel-group trial (the Cathedia Study) of 750 patients from a network of 9 tertiary care university medical centers and 3 general hospitals in France conducted between May 2004 and May 2007. The severely ill, bed-bound adults had a body mass index (BMI) of less than 45 and required a first catheter insertion for renal replacement therapy. INTERVENTION: Patients were randomized to receive jugular or femoral vein catheterization by operators experienced in placement at both sites. MAIN OUTCOME MEASURES: Rates of infectious complications, defined as catheter colonization on removal (primary end point), and catheter-related bloodstream infection. RESULTS: Patient and catheter characteristics, including duration of catheterization, were similar in both groups. More hematomas occurred in the jugular group than in the femoral group (13/366 patients [3.6%] vs 4/370 patients [1.1%], respectively; P = .03). The risk of catheter colonization at removal did not differ significantly between the femoral and jugular groups (incidence of 40.8 vs 35.7 per 1000 catheter-days; hazard ratio [HR], 0.85; 95% confidence interval [CI], 0.62-1.16; P = .31). A prespecified subgroup analysis demonstrated significant qualitative heterogeneity by BMI (P for the interaction term < .001). Jugular catheterization significantly increased incidence of catheter colonization vs femoral catheterization (45.4 vs 23.7 per 1000 catheter-days; HR, 2.10; 95% CI, 1.13-3.91; P = .017) in the lowest tercile (BMI <24.2), whereas jugular catheterization significantly decreased this incidence (24.5 vs 50.9 per 1000 catheter-days; HR, 0.40; 95% CI, 0.23-0.69; P < .001) in the highest tercile (BMI >28.4). The rate of catheter-related bloodstream infection was similar in both groups (2.3 vs 1.5 per 1000 catheter-days, respectively; P = .42). CONCLUSION: Jugular venous catheterization access does not appear to reduce the risk of infection compared with femoral access, except among adults with a high BMI, and may have a higher risk of hematoma. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00277888.

Role of hypermutability on bacterial fitness and emergence of resistance in experimental osteomyelitis due to Staphylococcus aureus.

This study was designed to investigate the role of hypermutability of Staphylococcus aureus on bacterial fitness and antibiotic resistance in a model of chronic bone infection. An isogenic pair of strains, S. aureus RN4220 and its mutator counterpart inactivated in the mutL gene were used in a rat model of osteomyelitis of the tibia. The effect of the mutator phenotype in the emergence of antibiotic resistance was assessed in rats infected by each strain separately and treated with rifampicin for 5 days. No difference between the two strains was found in bacterial growth in vitro and in bacterial survival in the animal model, indicating no fitness defect in the mutator strain. In competition studies performed in rats coinfected with the two strains at a same ratio and sacrificed at different times from day 3 to day 42 postinoculation, the mutator strain was clearly disadvantaged because it was found in all rats and at all study times at lower counts (P<0.05 from day 14 to day 42). Two of the 16 rats infected by the mutator strain and none of the 14 rats infected by the wild-type strain had acquired rifampicin-resistant mutants (P=0.4). Data suggest that the S. aureus mutator phenotype was associated with a decreased bacterial fitness in vivo and did not confer significant advantage in the acquisition of antibiotic resistance in a model of chronic bone infection.

Continuous renal replacement therapy may increase the risk of catheter infection.

BACKGROUND AND OBJECTIVES: Little is known about the risks of catheter-related infections in patients undergoing intermittent hemodialysis (IHD) as compared with continuous renal replacement therapy (CRRT) techniques. We compared the two modalities among critically ill adults requiring acute renal replacement therapy (RRT). DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: We used the multicenter Cathedia study cohort of 736 critically ill adults requiring RRT. Cox marginal structural models were used to compare time to catheter-tip colonization at removal (intent-to-treat, primary endpoint) among patients who started IHD (n = 470) versus CRRT (n = 266). On-treatment analysis was also conducted to take into account changes in prescription of RRT modality. RESULTS: Hazard rate of catheter-tip colonization did not increase within the first 10 days of catheter use. Predictors of catheter-tip colonization were higher lactate levels and hypertension, while systemic antibiotics, antiseptics-impregnated catheters, and mechanical ventilation were associated with decreased risk. The incidence of catheter-tip colonization per 1000 catheter-days was 42.7 in the IHD group and 27.7 in the CRRT group (P < 0.01). This association was no longer significant after correction for channeling bias (weighted HR, 0.96; 95% CI: 0.77 to 1.20, P = 0.73). On-treatment analysis revealed an increased risk of primary endpoint during CRRT exposure as compared with IHD exposure (weighted HR, 0.71; 95% CI: 0.56 to 0.92, P < 0.009). CONCLUSIONS: Our results do not support the use of CRRT when IHD could be an alternative to reduce the risk of catheter-related infection.