1150. Pediatric Osteoarticular Infections Caused by Mycobacteria Tuberculosis Complex: A Twenty-Six Year Review of Cases in San Diego, California

Background Osteoarticular infections (OAI) account for 10-20% of extrapulmonary Mycobacteria tuberculosis (MTB) complex infections in children. Given the rarity of MTB OAI, the epidemiology, disease manifestations, and treatment are poorly characterized. We describe 21 children treated for MTB complex OAI over a 26-year period at a tertiary pediatric center in southern California. Methods We conducted a retrospective review of children diagnosed with MTB complex OAI and cared for between 31 Dec 1992 to 31 Dec 2018 at a single tertiary care pediatric hospital with close proximity to the United States-Mexico border. Results We identified 21 children with MTB complex OAI during the study period (Table 1). Concurrent pulmonary disease (4.8%), meningitis (9.5%), and intra-abdominal involvement (14.3%) were all observed. MTB complex was identified by culture from operative samples in 15/21 children (71.4%); 8/15 (51.3%) cultures were positive for Mycobacterium bovis. Of the eight cases of vertebral OAI (the most common site), one was culture-positive for M. bovis. Open bone biopsy was the most common procedure for procurement of a tissue sample and had the highest culture yield (Table 2). The median duration of antimicrobial therapy was 52 weeks (IQR 52-58). Successful completion of therapy was documented in 15 children (71.4%). Seven children (33.3%) experienced long term sequelae related to their infection. Table 1. Twenty-one children with Mycobacteria tuberculosis complex osteoarticular infections. Table 2. Surgical sample type and percent positivity. Conclusion Among the 21 children with MTB complex OAI assessed, 8 of 15 (53.3%) children with a positive tissue culture had M. bovis (intrinsically resistant to pyrazinamide), representing a higher percentage than in previous reports and potentially reflecting its presence in unpasteurized dairy products in the California-Baja region. Local epidemiological trends in endemic MTB complex species should be considered when evaluating and managing MTB complex OAI. Bone biopsy produced the highest culture yield in this study. Given the rarity of this disease, multicenter collaborative studies are needed to improve our understanding of the presentation and management of pediatric MTB complex OAI. Disclosures Vanessa Raabe, MD, MSc, Pfizer (Scientific Research Study Investigator, Other Financial or Material Support, Editorial support)Sanofi (Scientific Research Study Investigator)

Tuberculosis-Associated Immune Reconstitution Inflammatory Syndrome Manifested As Multiple Central Nervous System Granulomas In Non-HIV Patient: A Case Report

Background: In addition to developed in HIV patient during highly active antiretroviral therapy, immune reconstitution inflammatory syndrome (IRIS) has also been well recognized in non-HIV immunocompromised patients induced by latent viruses, untreated microorganisms, or treating microorganisms. Mycobacteria tuberculosis is one of the most common pathogens inducing IRIS.Case presentation: Here, we report a tuberculosis patient progressed with IRIS that additional central nervous system (CNS) granuloma occurred during the anti-tuberculosis treatment (ATT) process with her pulmonary symptoms improved after quadruple anti-tuberculosis. This case highlights the need to increase the awareness of IRIS in non-HIV immunocompromised patients.Conclusions: TB-IRIS must be considered when the condition deteriorates or development of new lesions at distant sites in the course of ATT. Early identification and diagnosis help to handle timely and correctly.

Mycobacteria tuberculosis PPE36 modulates host inflammation by promoting E3 ligase Smurf1-mediated MyD88 degradation

Mycobacterium tuberculosis (Mtb) PPE36, a cell-wall associated protein is highly specific and conserved for the Mtb complex group. Although it has been proven essential for iron utilization, little is known about the role of PPE36 in regulating host immune responses. Here we exhibited that PPE36 preferentially enriched in Mtb virulent strains, and could efficiently inhibit host inflammatory responses and increase bacterial loads both in mycobacterium-infected macrophages and mice. In exploring the underlying mechanisms, we found that PPE36 could robustly inhibit the activation of inflammatory NF-κB and MAPK (ERK, p38 and JNK) pathways by promoting E3 ligase Smurf1-mediated ubiquitination and proteasomal degradation of MyD88 protein. Our research revealed a previously unknown function of PPE36 on modulating host immune responses, and provided some clues to the development of novel tuberculosis treatment strategies based on immune regulation.

THE INHIBITING EFFECT OF FS-1 DRUG ON THE ANTIOXIDANT PROTECTION SYSTEM OF MYCOBACTERIA TUBERCULOSIS

Results of inhibitory action of FS-1 drug on antioxidant system of pathogenic mycobacteria tuberculosis, including resistant MDR strain, are presented. The study of the effect of FS-1 drug on the activity of the antioxidant system was carried out on the reference strain Mycobacterium tuberculosis H37Rv and MDR (rifampicin, isoniazid, streptomycin, ethambutol, еthionamide, kanamycin, cycloserine and pyrazinamide resistant) strain Mycobacterium tuberculosis 320. FS-1 drug under experimental conditions in vitro showed a new mechanism of action on mycobacteria tuberculosis - suppression of functional activity of the enzyme superoxide dismutase, which protects the microorganism from oxidative stress. The loss of resistance to oxidative stress by a bacterial cell, i.e. the ability to neutralize highly toxic oxygen radicals, leads to the destruction of cellular structures, metabolic and energy processes, disruption of the respiratory system and, as a result, its death. Antioxidant activity of Mycobacterium tuberculosis H37Rv after exposure with FS-1 preparation at concentrations of 4µg/ml is inhibited by 90.64 %, while at concentration of 2 µg/ml on bacterial culture of this strain - by 89.07 %. The obtained results show significant suppression of functional activity of superoxide dismutase enzyme in bacterial culture of Mycobacterium tuberculosis H37Rv under the influence of FS-1 in these concentrations, showing pronounced inhibitory effect. Similar studies of the effect of iodine-containing FS-1 drug on the antioxidant system were carried out on the bacterial culture of M. tuberculosis multidrug resistant strain 320. It was found that antioxidant activity of FS-1 preparation in concentration 4 µg/ml is inhibited by 99 %, while in concentrations 2 µg/ml FS-1preparation suppresses antioxidant activity of strain 320 by 98 %. Thus, the studies showed that the FS-1 preparation at the test concentrations of 4 μg/ml and 2 μg/ml has a mechanism for pronounced inhibition of the functional activity of the enzyme superoxide dismutase in Mycobacterium tuberculosis of both the reference sensitive strain H37Rv and the multidrug resistant strain 320. This leads to disruption of the redox transformations of various chemical compounds that form the respiratory process in the bacterial culture, providing the energy demand of the microorganism.

Nicotine Modulates MyD88-Dependent Signaling Pathway in Macrophages during Mycobacterial Infection

Recently, we reported that cigarette smoking, and especially nicotine, increases susceptibility to mycobacterial infection and exacerbates inflammation in patients with Crohn’s disease (CD). The macrophagic response to Mycobacterium avium subspecies paratuberculosis (MAP) in CD and Mycobacteria tuberculosis (MTB) continues to be under investigation. The role of toll-like-receptors (TLRs) and cytoplasmic adaptor protein (MyD88) in proinflammatory response during Mycobacterial infection has been suggested. However, the mechanism of how nicotine modulates macrophage response during infection in CD and exacerbates inflammatory response remain unclear. In this study, we elucidated the mechanistic role of nicotine in modulating MyD88-dependent/TLR pathway signaling in a macrophage system during mycobacterial infection. The data demonstrated that MAP infection in THP-1 derived macrophages was mediated through TLR2 and MyD88 leading to increase in IL-8 in expression and production. On the other hand, LPS-representing, Gram-negative bacteria mediated macrophage response through TLR4. Blocking TLR2 and TLR4 with antagonists voided the effect of MAP, and LPS, respectively in macrophages and reversed response with decrease in expression of iNOS, TNF-α and IL-8. Interestingly, nicotine in infected macrophages significantly (1) downregulated TLR2 and TLR4 expression, (2) activated MyD88, (3) increased M1/M2 ratio, and (4) increased expression and secretion of proinflammatory cytokines especially IL-8, as seen in CD smokers. We also discovered that blocking macrophages during MAP infection with MyD88 antagonist significantly decreased response which illustrates the key role for MyD88 during infection. Surprisingly, dual treatment of MAP-infected macrophages with MyD88 antagonist and nicotine absolutely impaired immune response and decreased MAP viability, which clearly validate the inflammatory role of nicotine in macrophages through TLR2/MyD88 pathway during infection. This is the first report to describe the mechanism by which nicotine modulates TLR2/MyDD88 and exacerbates inflammation in CD smokers associated with infection.