Mucispirillum schaedleri: Biofilm Architecture and Age-Dependent Pleomorphy

Round bodies in spirochete cultures have been a controversial subject since their description seven decades ago. We report the existence of round bodies (spherical cells) in cultures of Mucispirillum schaedleri, a spiral bacterium phylogenetically distant from spirochetes. Furthermore, when grown in biofilms, M. schaedleri demonstrates a unique morphology known as cording, which has been previously described only in mycobacteria. Thus, M. schaedleri has two distinct features, each previously thought to be unique to two different phylogenetically distant groups of bacteria.

Lymphoscintigraphic Investigations for Axillary Web Syndromes

Background: Axillary web syndrome (AWS) is a frequent complication after surgery for breast cancer, but its lymphatic involvement is not definitively established. Here we report the results of lymphoscintigraphic investigations in patients with AWS. Methods and Findings: We conducted a retrospective, single-center review of lymphoscintigraphic investigations performed in 46 patients with AWS that was either clinically obvious or suspected. Of this group, 23 patients had two investigations with a mean interval of 19 weeks between them (range, 6-98 weeks). Results of the lymphoscintigraphic investigations, which were performed according to a well-standardized protocol, were classified into four patterns: normal; functional lymphatic insufficiency only (no lymphatic vascular morphologic abnormality); lymphovascular blockade without collateralization; and vascular collateralization and/or dermal backflow. Of the 46 patients, on the first lymphoscintigraphic investigation, four (8.6%) had a normal pattern, seven (15.2%) had functional lymphatic insufficiency only, four (8.6%) had lymphovascular blockade without collateralization, and 31 (67.3%) had vascular collateralization and/or dermal backflow. Among patients who underwent two investigations, four of the five who had only functional lymphatic insufficiency at the first investigation had developed vascular collateralization and/or dermal backflow by the second. The three patients who had lymphovascular blockade without collateralization at the first examination had also progressed to collateralization and/or dermal backflow at the second. None of the 15 patients who initially had vascular collateralization and/or dermal backflow showed any reversal at the second examination. Conclusions: Our analysis confirms the lymphatic nature of AWS and shows the lymphoscintigraphic patterns and evolutions of the lymphatic lesions with potential therapeutic implications. The retrospective review of our database is approved by the institutional ethics committee under number 2048.

Cording in Disseminated Mycobacterium chelonae Infection in an Immunocompromised Patient

Cording is a phenomenon in which acid fast bacilli grow in parallel and was previously used as a means of presumptive microscopic identification of Mycobacterium tuberculosis (TB). However, this process has been shown in multiple other nontuberculous mycobacterial (NTM) species. Here we present the case of an immunocompromised adult who presented with wrist pain, weight loss, and cough. A positron emission tomography scan showed uptake in the right ulna, multiple soft tissue sites, and the left lung. Biopsies and cultures were obtained from multiple sites, and the patient was ultimately diagnosed with disseminated Mycobacterium chelonae infection. The organism showed cording in culture. As seen in this patient, cording may occur in multiple NTM species and is not reliable as the sole indicator of the presence of TB.

CFTR Depletion Confers Hypersusceptibility to Mycobacterium fortuitum in a Zebrafish Model

The Mycobacterium fortuitum complex comprises several closely related species, causing pulmonary and extra-pulmonary infections. However, there is very limited knowledge about the disease pathogenesis involved in M. fortuitum infections, particularly due to the lack of suitable animal models. Using the zebrafish model, we show that embryos are susceptible to M. fortuitum infection in a dose-dependent manner. Furthermore, zebrafish embryos form granulomas from as early as 2 days post-infection, recapitulating critical aspects of mycobacterial pathogenesis observed in other pathogenic species. The formation of extracellular cords in infected embryos highlights a previously unknown pathogenic feature of M. fortuitum. The formation of large corded structures occurs also during in vitro growth, suggesting that this is not a host-adapted stress mechanism deployed during infection. Moreover, transient macrophage depletion led to rapid embryo death with increased extracellular cords, indicating that macrophages are essential determinants of M. fortuitum infection control. Importantly, morpholino depletion of the cystic fibrosis transmembrane conductance regulator (cftr) significantly increased embryo death, bacterial burden, bacterial cords and abscesses. There was a noticeable decrease in the number of cftr-deficient infected embryos with granulomas as compared to infected controls, suggesting that loss of CFTR leads to impaired host immune responses and confers hypersusceptiblity to M. fortuitum infection. Overall, these findings highlight the application of the zebrafish embryo to study M. fortuitum and emphasizes previously unexplored aspects of disease pathogenesis of this significant mycobacterial species.

Patients who report cording after breast cancer surgery are at higher risk of lymphedema: Results from a large prospective screening cohort

OBJECTIVES

To identify the association between cording and breast cancer-related lymphedema (BCRL); describe time course, location, symptoms and functional impairments.

METHODS

A total of 1181 patients were prospectively screened for BCRL after breast cancer (BC) surgery, including patient-reported outcome measures (4193) and perometric arm volume measurements (BCRL defined as relative or weight-adjusted volume change [RVC or WAC] ≥10% ≥3 months postoperatively).

RESULTS

A total of 374/1181 patients (31.7%) reported cording first a median of 4.5 months postoperatively, and were more likely to: have body mass index less than 30 kg/m² ; be less than 55 years of age; have had mastectomy, axillary lymph node dissection, regional lymph node radiation, neoadjuvant chemotherapy (all P < .001), or RVC/WAC ≥10% (P = .002). Patients who reported cording had 2.4 times the odds of developing BCRL compared to those who did not (odds ratio = 2.40; 95% confidence interval = 1.40-4.11; P = .002), and most frequently reported these symptoms: tenderness (61.2%), aching (60.7%), and firmness/tightness (59.8%). On multivariable analysis, cording was significantly correlated with functional difficulty for 17 actions.

CONCLUSIONS

Patients frequently present with cording, potentially months after BC surgery. Risk factors for and symptoms of cording are identified, and treatment is recommended. Patients reporting cording are at higher risk of BCRL, therefore, cording should be incorporated into BCRL risk stratification.

Cording Mycobacterium tuberculosis Bacilli Have a Key Role in the Progression towards Active Tuberculosis, Which is Stopped by Previous Immune Response

Cording was the first virulence factor identified in Mycobacterium tuberculosis (Mtb). We aimed to ascertain its role in the induction of active tuberculosis (TB) in the mouse strain C3HeB/FeJ by testing the immunopathogenic capacity of the H37Rv strain. We have obtained two batches of the same strain by stopping their growth in Proskauer Beck liquid medium once the mid-log phase was reached, in the noncording Mtb (NCMtb) batch, and two days later in the cording Mtb (CMtb) batch, when cording could be detected by microscopic analysis. Mice were challenged with each batch intravenously and followed-up for 24 days. CMtb caused a significant increase in the bacillary load at an early stage post-challenge (day 17), when a granulomatous response started, generating exudative lesions characterized by neutrophilic infiltration, which promoted extracellular bacillary growth together with cording formation, as shown for the first time in vivo. In contrast, NCMtb experienced slight or no bacillary growth and lesions could barely be detected. Previous Bacillus Calmette-Guérin (BCG) vaccination or low dose aerosol (LDA) Mtb infection were able to delay the progression towards active TB after CMtb challenge. While BCG vaccination also reduced bacillary load when NCMtb was challenged, LDA did not, and its proliferative lesions experienced neutrophil infiltration. Analysis of lung cytokine and chemokine profiles points to their capacity to block the production of CXCL-1 and further amplification of IL-1β, IL-17 and neutrophilic extracellular trap formation, all of which are essential for TB progression. These data highlight the key role of cording formation in the induction of active TB.

Axillary web syndrome following breast cancer surgery: symptoms, complications, and management strategies

Axillary web syndrome (AWS) is a common condition occurring in up to 86% of patients following breast cancer surgery with ipsilateral lymphadenectomy of one or more nodes. AWS presents as a single cord or multiple thin cords in the subcutaneous tissues of the ipsilateral axilla. The cords may extend variable distances "down" the ipsilateral arm and/or chest wall. The cords frequently result in painful shoulder abduction and limited shoulder range of motion. AWS most frequently becomes symptomatic between 2 and 8 weeks postoperatively but can also develop and recur months to years after surgery. Education about and increased awareness of AWS should be promoted for patients and caregivers. Assessments for AWS should be performed on a regular basis following breast cancer surgery especially if there has been associated lymphadenectomy. Physical therapy, which consists of manual therapy, exercise, education, and other rehabilitation modalities to improve range of motion and decrease pain, is recommended in the treatment of AWS.

The Cording Phenotype of Mycobacterium tuberculosis Induces the Formation of Extracellular Traps in Human Macrophages

The causative agent of tuberculosis, Mycobacterium tuberculosis, shares several characteristics with organisms that produce biofilms during infections. One of these is the ability to form tight bundles also known as cords. However, little is known of the physiological relevance of the cording phenotype. In this study, we investigated whether cord-forming M. tuberculosis induce the formation of macrophage extracellular traps (METs) in human monocyte-derived macrophages. Macrophages have previously been shown to produce extracellular traps in response to various stimuli. We optimized bacterial culturing conditions that favored the formation of the cord-forming phenotype as verified by scanning electron microscopy. Microscopy analysis of METs formation during experimental infection of macrophages with M. tuberculosis revealed that cord-forming M. tuberculosis induced significantly more METs compared to the non-cording phenotype. Deletion of early secreted antigenic target-6 which is an important virulence factor of M. tuberculosis, abrogated the ability of the bacteria to induce METs. The release of extracellular DNA from host cells during infection may represent a defense mechanism against pathogens that are difficult to internalize, including cord-forming M. tuberculosis.

Deletion of a dehydratase important for intracellular growth and cording renders rough Mycobacterium abscessus avirulent

Mycobacterium abscessus (Mabs) is a rapidly growing Mycobacterium and an emerging pathogen in humans. Transitioning from a smooth (S) high-glycopeptidolipid (GPL) producer to a rough (R) low-GPL producer is associated with increased virulence in zebrafish, which involves the formation of massive serpentine cords, abscesses, and rapid larval death. Generating a cord-deficient Mabs mutant would allow us to address the contribution of cording in the physiopathological signs of the R variant. Herein, a deletion mutant of MAB_4780, encoding a dehydratase, distinct from the β-hydroxyacyl-ACP dehydratase HadABC complex, was constructed in the R morphotype. This mutant exhibited an alteration of the mycolic acid composition and a pronounced defect in cording. This correlated with an extremely attenuated phenotype not only in wild-type but also in immunocompromised zebrafish embryos lacking either macrophages or neutrophils. The abolition of granuloma formation in embryos infected with the dehydratase mutant was associated with a failure to replicate in macrophages, presumably due to limited inhibition of the phagolysosomal fusion. Overall, these results indicate that MAB_4780 is required for Mabs to successfully establish acute and lethal infections. Therefore, targeting MAB_4780 may represent an attractive antivirulence strategy to control Mabs infections, refractory to most standard chemotherapeutic interventions. The combination of a dehydratase assay with a high-resolution crystal structure of MAB_4780 opens the way to identify such specific inhibitors.

Characterizing axillary web syndrome: ultrasonographic efficacy

The aim of this study was to determine if ultrasound could successfully characterize axillary web syndrome (AWS) and clarify the pathophysiologic basis of AWS as a vascular or lymphatic abnormality, or an abnormal tissue structure. This prospective study evaluated women who developed AWS following breast cancer surgery. Using an 18 MHz ultrasound transducer, images were taken of the AWS cord and compared to mirror images on the contralateral side. A blinded radiologist assessed the ultrasound characteristics of and structural changes in the skin and subcutaneous tissue and formulated an opinion as to the side in which AWS was located. Seventeen subjects participated in the study. No structure or abnormality consistent with AWS could be identified by ultrasound. There were no statistical differences between the ipsilateral and contralateral side in skin thickness; subcutaneous reflector thickness, number or disorganization; or subcutaneous tissue echodensity (p>0.05). The radiologist correctly identified the side with AWS in 12 of 17 subjects (=0.41). A distinct ultrasonographic structure or abnormality could not be identified in subjects with AWS using 18 MHz ultrasound. The inability to identify a specific structure excludes the possibility that AWS is associated with vein thrombosis or a fascial abnormality, and supports the theory that AWS may be pathology that is not visible with 18 MHz ultrasound, such as microlymphatic stasis or binding of fibrin or other proteins in the interstitial space.