A case of novel, rapidly-growing Mycolicibacter kumamotonensis infection in a patient with severe pulmonary disease treated in New York City.

INTRODUCTION: Mycolicibacter kumamotonensis is a slowly growing, non-chromogenic non-tuberculous mycobacteria (NTM) that was initially distinguished from the M. terrae complex in 2006. Since then it has been rarely reported as the cause of pulmonary and soft-tissue infections in both immunocompromised and immunocompetent patients. CASE PRESENTATION: We present a case of severe pulmonary disease due to Mycolicibacter kumamotonensis in a 57-year-old male who was immunocompetent at time of diagnosis, with a history of interstitial lung disease and a prior diagnosis of tuberculosis (TB). After initial treatment for TB in 2017, his condition stabilized until a recurrence in September 2021, leading to an evaluation for lung transplant in the setting of pulmonary fibrosis and emphysema which led to the identification of Mycolicibacter kumamotonensis. A lung transplant was completed, and the patient was successfully treated with a combination of Ethambutol, Azithromycin, and Rifabutin. CONCLUSIONS: This represents the first case reported of M. kumamotonensis in a patient undergoing lung transplant, and the first case with rapid culture growth during identification of the organism (4 days). This report highlights the need for consideration of M. kumamotonensis as a pathogen in humans, with the potential for rapid growth in liquid media, and the importance of early identification to inform empiric therapy.

Bacterial Pneumonia and Respiratory Culture Utilization among Hospitalized Patients with and without COVID-19 in a New York City Hospital.

COVID-19 is associated with prolonged hospitalization and a high risk of intubation, which raises concern for bacterial coinfection and antimicrobial resistance. Previous research has shown a wide range of bacterial pneumonia rates for COVID-19 patients in a variety of clinical and demographic settings, but none have compared hospitalized COVID-19 patients to patients testing negative for severe acute respiratory syndrome coronavirus (SARS-CoV-2) in similar care settings. We performed a retrospective cohort study on hospitalized patients with COVID-19 testing from March 10th, 2020 to December 31st, 2020. A total of 19,219 patients were included, of which 3,796 tested positive for SARS-CoV-2. We found a 2.6-fold increase (P < 0.001) in respiratory culture ordering in COVID-19 patients. On a per-patient basis, COVID-19 patients were 1.5-fold more likely than non-COVID patients to have positive respiratory cultures (46.8% versus 30.9%, P < 0.001), which was primarily driven by patients requiring intubation. Among patients with pneumonia, a significantly higher proportion of COVID-19 patients had ventilator-associated pneumonia (VAP) relative to non-COVID patients (86.3% versus 70.8%, P < 0.001), but a lower proportion had community-acquired (11.2% vs 25.5%, P < 0.01) pneumonia. There was also a significantly higher proportion of respiratory cultures positive for methicillin-resistant Staphylococcus aureus, Klebsiella pneumoniae, and antibiotic-resistant organisms in COVID-19 patients. Increased rates of respiratory culture ordering for COVID-19 patients therefore appear to be clinically justified for patients requiring intubation, but further research is needed to understand how SARS-CoV-2 increases the risk of VAP.

Assessing respiratory viral exclusion and affinity interactions through co-infection incidence in a pediatric population during the 2022 resurgence of influenza and RSV.

Introduction: In the Northeast US, respiratory viruses such as influenza and respiratory syncytial virus (RSV), which were largely suppressed by COVID-19-related social distancing, made an unprecedented resurgence during 2022, leading to a substantial rise in viral co-infections. However, the relative rates of co-infection with seasonal respiratory viruses over this period have not been assessed. Methods: Here we reviewed multiplex respiratory viral PCR data (BioFire FilmArray™ Respiratory Panel v2.1 [RPP]) from patients with respiratory symptoms presenting to our medical center in New York City to assess co-infection rates of respiratory viruses, which were baselined to total rates of infection for each virus. We examined trends in monthly RPP data from adults and children during November 2021 through December 2022 to capture the full seasonal dynamics of respiratory viruses across periods of low and high prevalence. Results: Of 50,022 RPPs performed for 34,610 patients, 44% were positive for at least one target, and 67% of these were from children. The overwhelming majority of co-infections (93%) were seen among children, for whom 21% of positive RPPs had two or more viruses detected, as compared to just 4% in adults. Relative to children for whom RPPs were ordered, children with co-infections were younger (3.0 vs 4.5 years) and more likely to be seen in the ED or outpatient settings than inpatient and ICU settings. In children, most viral co-infections were found at significantly reduced rates relative to that expected from the incidence of each virus, especially those involving SARS-CoV-2 and influenza. SARS-CoV-2 positive children had an 85%, 65% and 58% reduced rate of co-infection with influenza, RSV, and Rhino/enteroviruses, respectively, after compensating for the incidence of infection with each virus (p< 0.001). Discussion: Our results demonstrate that most respiratory viruses peaked in different months and present in co-infections less than would be expected based on overall rates of infection, suggesting a viral exclusionary effect between most seasonal respiratory viruses, including SARS-CoV-2, influenza and RSV. We also demonstrate the significant burden of respiratory viral co-infections among children. Further work is necessary to understand what predisposes certain patients for viral co-infection despite this exclusionary effect.

Laboratory Biomarkers in the Management of Patients With COVID-19.

OBJECTIVES: Laboratory testing and the measurement of appropriate biomarkers play a critical role in managing patients with coronavirus disease 2019 (COVID-19), allowing for disease diagnosis, monitoring progression, prognostication, prediction of treatment response, and risk stratification. We sought to characterize these effects on a more detailed, mechanistic level. METHODS: We reviewed the literature and identified a multitude of reports that describe the unique effects of this virus and its devastating consequences to multiple organ systems in COVID-19 patients. RESULTS: There are specific alterations in biomarkers related to coagulation, depopulation of T-cell subtypes, the cytokine storm and inflammation, and kidney and cardiac dysfunction. CONCLUSIONS: Laboratory measurement of specific parameters and the use of appropriate prognostic, predictive, and monitoring biomarkers afford clinicians the ability to make informed medical decisions and guide therapy for patients afflicted with this dreaded disease.

Sox2 and Canonical Wnt Signaling Interact to Activate a Developmental Checkpoint Coordinating Morphogenesis with Mesoderm Fate Acquisition.

Animal embryogenesis requires a precise coordination between morphogenesis and cell fate specification. During mesoderm induction, mesodermal fate acquisition is tightly coordinated with the morphogenetic process of epithelial-to-mesenchymal transition (EMT). In zebrafish, cells exist transiently in a partial EMT state during mesoderm induction. Here, we show that cells expressing the transcription factor Sox2 are held in the partial EMT state, stopping them from completing the EMT and joining the mesoderm. This is critical for preventing the formation of ectopic neural tissue. The mechanism involves synergy between Sox2 and the mesoderm-inducing canonical Wnt signaling pathway. When Wnt signaling is inhibited in Sox2-expressing cells trapped in the partial EMT, cells exit into the mesodermal territory but form an ectopic spinal cord instead of mesoderm. Our work identifies a critical developmental checkpoint that ensures that morphogenetic movements establishing the mesodermal germ layer are accompanied by robust mesodermal cell fate acquisition.

Early and prolonged opportunities to practice suturing increases medical student comfort with suturing during clerkships: Suturing during cadaver dissection.

Medical students are expected to perform common procedures such as suturing on patients during their third-year clerkships. However, these experiences are often viewed by medical students as stressors rather than opportunities for learning. The source of this stress is the lack of instruction on common procedures prior to being asked to observe or perform the procedure on a patient. First-time exposures to procedures in stressful environments may result in decreased confidence in medical students and decrease the frequency with which they perform these procedures in the future. The authors sought to change this paradigm by: (1) introducing a suturing module to first-year medical students in the context of the anatomy dissection laboratory and (2) measuring its effects on student attitudes and behavior over the course of their third-year clerkships when they encounter patients. The authors found that early and prolonged introduction to suturing was associated with increased student confidence relative to suturing a patient. Participation in the suturing module was associated with increased student confidence in identifying suturing instruments (P < 0.001) and suturing patients (P = 0.013). Further it positively affected their behavior as demonstrated by increased performance of suturing events from students exposed to the suturing module. (P < 0.001) This study demonstrates that early and prolonged opportunities to practice a procedural skill in a low-stress environment increases student confidence during patient interactions and alters student behavior.

Tumor Cell Invadopodia: Invasive Protrusions that Orchestrate Metastasis.

Invadopodia are a subset of invadosomes that are implicated in the integration of signals from the tumor microenvironment to support tumor cell invasion and dissemination. Recent progress has begun to define how tumor cells regulate the plasticity necessary for invadopodia to assemble and function efficiently in the different microenvironments encountered during dissemination in vivo. Exquisite mapping by many laboratories of the pathways involved in integrating diverse invadopodium initiation signals, from growth factors, to extracellular matrix (ECM) and cell-cell contact in the tumor microenvironment, has led to insight into the molecular basis of this plasticity. Here, we integrate this new information to discuss how the invadopodium is an important conductor that orchestrates tumor cell dissemination during metastasis.

MenaINV dysregulates cortactin phosphorylation to promote invadopodium maturation.

Invadopodia, actin-based protrusions of invasive carcinoma cells that focally activate extracellular matrix-degrading proteases, are essential for the migration and intravasation of tumor cells during dissemination from the primary tumor. We have previously shown that cortactin phosphorylation at tyrosine residues, in particular tyrosine 421, promotes actin polymerization at newly-forming invadopodia, promoting their maturation to matrix-degrading structures. However, the mechanism by which cells regulate the cortactin tyrosine phosphorylation-dephosphorylation cycle at invadopodia is unknown. Mena, an actin barbed-end capping protein antagonist, is expressed as various splice-isoforms. The MenaINV isoform is upregulated in migratory and invasive sub-populations of breast carcinoma cells, and is involved in tumor cell intravasation. Here we show that forced MenaINV expression increases invadopodium maturation to a far greater extent than equivalent expression of other Mena isoforms. MenaINV is recruited to invadopodium precursors just after their initial assembly at the plasma membrane, and promotes the phosphorylation of cortactin tyrosine 421 at invadopodia. In addition, we show that cortactin phosphorylation at tyrosine 421 is suppressed by the phosphatase PTP1B, and that PTP1B localization to the invadopodium is reduced by MenaINV expression. We conclude that MenaINV promotes invadopodium maturation by inhibiting normal dephosphorylation of cortactin at tyrosine 421 by the phosphatase PTP1B.