Rapidly Growing Mycobacteria Infections Research Articles

Anti-biofilm activities and antibiotic synergy of naturally occurring compounds against drug-resistant rapidly growing mycobacteria.

The emergence of antimicrobial resistance within rapidly growing mycobacteria (RGM) poses a significant threat to public health. This study investigates the potential of naturally occurring compounds to combat infections caused by antibiotic-resistant RGM including M. abscessus, M. fortuitum, and M. chelonae. We identified four specific natural compounds showing impressive inhibitory effects against antibiotic-resistant clinical strains. These compounds not only inhibited the growth and biofilm formation but also exhibited synergistic interactions with antibiotics against key RGM pathogens. Our findings highlight the alternative treatment strategies for RGM infections and potential environmental applications of these natural compounds in mitigating microbial persistence and controlling infectious diseases.

Neurological manifestations of nontuberculous mycobacteria in adults: case series and review of the literature.

Nontuberculous mycobacteria (NTM) mediated infections are important to consider in cases with neuroinflammatory presentations. We aimed to characterize cases of NTM with neurological manifestations at the National Institutes of Health (NIH) Clinical Center and review the relevant literature. Between January 1995 and December 2020, six cases were identified. Records were reviewed for demographic, clinical, and radiological characteristics. A MEDLINE search found previously reported cases. Data were extracted, followed by statistical analysis to compare two groups [cases with slow-growing mycobacteria (SGM) vs. those with rapidly growing mycobacteria (RGM)] and evaluate for predictors of survival. NIH cases were evaluated for clinical and radiological characteristics. Cases from the literature were reviewed to determine the differences between SGM and RGM cases and to identify predictors of survival. Six cases from NIH were identified (age 41 ± 13, 83% male). Five cases were caused by SGM [Mycobacterium avium complex (MAC) n = 4; Mycobacterium haemophilum n = 1] and one due to RGM (Mycobacterium abscessus). Underlying immune disorders were identified only in the SGM cases [genetic (n = 2), HIV (n = 1), sarcoidosis (n = 1), and anti-interferon-gamma antibodies (n = 1)]. All cases were diagnosed using tissue analysis. A literature review found 81 reports on 125 cases (SGM n = 85, RGM n = 38, non-identified n = 2). No immune disorder was reported in 26 cases (21%). Within SGM cases, the most common underlying disease was HIV infection (n = 55, 65%), and seizures and focal lesions were more common. In RGM cases, the most common underlying condition was neurosurgical intervention or implants (55%), and headaches and meningeal signs were common. Tissue-based diagnosis was used more for SGM than RGM (39% vs. 13%, p = 0.04). Survival rates were similar in both groups (48% SGM and 55% in RGM). Factors associated with better survival were a solitary CNS lesion (OR 5.9, p = 0.01) and a diagnosis made by CSF sampling only (OR 9.9, p = 0.04). NTM infections cause diverse neurological manifestations, with some distinctions between SGM and RGM infections. Tissue sampling may be necessary to establish the diagnosis, and an effort should be made to identify an underlying immune disorder.

1895. Omadacycline for the Treatment of Non-Pulmonary Mycobacterial Infections: a Single-Center Retrospective Review

Abstract Background Infections due to rapidly growing mycobacteria (RGM) such as M. abscessus, M. chelonae and M. fortuitum typically require long and toxic regimens, with complex resistance patterns and limited oral options further producing suboptimal efficacy. Since its approval in 2018, however, the tetracycline derivative omadacycline has established new options in antibiotic management. We report here clinical experience with the use of omadacycline for non-pulmonary RGM infections within the Mass General Brigham (MGB) system. Methods The study was approved by the MGB Institutional Review Board (2022P001578). Electronic ambulatory notes in the MGB Research Patient Data Registry (RPDR) from 2012-present were filtered by the term “omadacycline,” and manual chart review was conducted for individuals treated for non-pulmonary RGM infections. Flow diagram of chart review procedure for identification of non-pulmonary RGM patients Results Chart review revealed 25 patients with omadacycline-treated non-pulmonary RGM infections. The median age was 50, 52% female and 48% male. In total, 16 were infected with M. abscessus (64%), 8 with M. chelonae (32%), and 1 with M. immunogenum. 18 cases were skin and soft tissue infections (72%), 4 cases were bone and joint infections (16%), and 3 cases were disseminated infections (12%). Most patients (88%) received omadacycline as part of a step-down or a salvage regimen; 3 (12%) received omadacycline in initial treatment. 17 patients (68%) had completed regimens as of April 2023. Among these cases, the median duration of omadacycline use was 5 months (range=0.25-16). Patients within this cohort generally experienced clinical improvement. Adverse effects–most commonly nausea–were noted in 6 (24%) cases. No patients were discontinued due to the severity of these effects, though one regimen was temporarily paused due to hyperlipasemia. Non-pulmonary RGM patient cohort demographics, Mycobacterial species, and site of infection. Conclusion Omadacycline is an increasingly common component of the treatment of RGM infections, with use in multidrug regimens appearing generally effective and well-tolerated. Limitations of this study include its retrospective nature and evaluation within a single health system. To our knowledge, however, this is the largest series on omadacycline in RGM infections reported to-date. This analysis provides support for the further evaluation of omadacycline outcomes among patients with RGM infections. Disclosures All Authors: No reported disclosures

Emergence of Inducible Macrolide Resistance in Mycobacterium chelonae Due to Broad-Host-Range Plasmid and Chromosomal Variants of the Novel 23S rRNA Methylase Gene, erm(55).

Macrolides are a mainstay of therapy for infections due to nontuberculous mycobacteria (NTM). Among rapidly growing mycobacteria (RGM), inducible macrolide resistance is associated with four chromosomal 23S rRNA methylase (erm) genes. Beginning in 2018, we detected high-level inducible clarithromycin resistance (MICs of ≥16μg/mL) in clinical isolates of Mycobacterium chelonae, an RGM species not previously known to contain erm genes. Using whole-genome sequencing, we identified a novel plasmid-mediated erm gene. This gene, designated erm(55)P, exhibits <65% amino acid identity to previously described RGM erm genes. Two additional chromosomal erm(55) alleles, with sequence identities of 81% to 86% to erm(55)P, were also identified and designated erm(55)C and erm(55)T. The erm(55)T is part of a transposon. The erm(55)P allele variant is located on a putative 137-kb conjugative plasmid, pMchErm55. Evaluation of 133 consecutive isolates from 2020 to 2022 revealed 5 (3.8%) with erm(55). The erm(55)P gene was also identified in public data sets of two emerging pathogenic pigmented RGM species: Mycobacterium iranicum and Mycobacterium obuense, dating back to 2008. In both species, the gene appeared to be present on plasmids homologous to pMchErm55. Plasmid-mediated macrolide resistance, not described previously for any NTM species, appears to have spread to multiple RGM species. This has important implications for antimicrobial susceptibility guidelines and treatment of RGM infections. Further spread could present serious consequences for treatment of other macrolide-susceptible RGM. Additional studies are needed to determine the transmissibility of pMchErm55 and the distribution of erm(55) among other RGM species.

High Rates of Antimicrobial Resistance in Rapidly Growing Mycobacterial Infections in Taiwan.

Rapidly growing mycobacteria (RGM) has gained increasing clinical importance, and treatment is challenging due to diverse drug resistance. The minimum inhibitory concentrations (MIC) of 13 antimicrobial agents using modified broth microdilution and E-test were determined for 32 clinical isolates of RGM, including Mycobacterium abscessus (22 isolates) and Mycobacterium fortuitum (10 isolates). Our results showed high rates of resistance to available antimicrobial agents. Amikacin remained highly susceptible (87.5%). Clarithromycin was active against the isolates of M. abscessus (95.5%), and M. fortuitum (50%), but 36.4% and 20% had inducible macrolide resistance, respectively. Rates of susceptibility to tigecycline were 68.2–70%, and linezolid 45.5–50%, respectively. The quinolones (ciprofloxacin and moxifloxacin) showed better in vitro activity against M. fortuitum isolates (50% susceptibility) than the M. abscessus isolates (31.8% susceptibility). The susceptibilities to other conventional anti-mycobacterial agents were poor. The MICs of E-test were higher than broth microdilution and may result in reports of false resistance. In conclusion, the implementation of the modified broth microdilution plates into the routine clinical laboratory workflow to provide antimicrobial susceptibility early, allows for the timely selection of appropriate treatment of RGM infections to improve outcome.

Investigation of a cluster of rapidly growing mycobacteria infections associated with joint replacement surgery in a Kentucky hospital, 2013–2014 with 8-year follow-up

We describe the investigation of a nosocomial outbreak of rapidly growing mycobacteria (RGM) infections and the results of mitigation efforts after 8 years. A cluster of RGM cases in a Kentucky hospital in 2013 prompted an investigation into RGM surgical site infections following joint replacement surgery. A case-control study was conducted to identify risk factors. Eight cases were identified, 5 caused by M. wolinskyi and 3 by M. goodii. The case-control study showed the presence of a particular nurse in the operating room was significantly associated with infection. Environmental sampling at the nurse's home identified an outdoor hot tub as the likely source of M. wolinskyi, confirmed by pulsed-field gel electrophoresis and whole genome sequencing. The hot tub reservoir was eliminated, and hospital policies were revised to correct infection control lapses. No new cases of RGM infections have been identified as of 2021. Breaches in infection control practices at multiple levels may have led to a chain of infection from a nurse's hot tub to surgical sites via indirect person-to-person transmission from a colonized health care worker (HCW). The multifactorial nature of the outbreak's cause highlights the importance of overlapping or redundant layers of protection preventing patient harm. Future investigations of RGM outbreaks should consider the potential role of colonized HCWs as a transmission vector.

Development of a nucleic acid chromatography assay for the detection of commonly isolated rapidly growing mycobacteria.

Introduction. Non-tuberculosis mycobacterium infections are increasing worldwide, including those caused by rapidly growing mycobacteria (RGM).Gap Statement. The identification of the aetiological agent in the context of infections is essential for the adoption of an adequate therapeutic approach. However, the methods for the rapid distinction of different RGM species are less than optimal.Aim. To develop a nucleic acid chromatography kit to identify clinically common RGM.Methodology. We tried to develop a nucleic acid chromatography kit designed to detect four RGM species (including three subspecies) i.e. Mycobacterium abscessus subsp. abscessus, Mycobacterium abscessus subsp. bolletii (detected as M. abscessus/bolletii) Mycobacterium abscessus subsp. massiliense, Mycobacterium fortuitum, Mycobacterium chelonae and Mycobacterium peregrinum. The amplified target genes for each species/subspecies using multiplex PCR were analysed using a nucleic acid chromatography assay.Results. Among the 159 mycobacterial type strains and 70 RGM clinical isolates tested, the developed assay correctly identified all relevant RGM without any cross-reactivity or false-negatives. The limits of detection for each species were approximately 0.2 pg µl-1.Conclusion. The rapid and simple nucleic acid chromatography method developed here, which does not involve heat denaturation, may contribute to the rapid identification and treatment of RGM infections.

Comparison of the in vitro activity of linezolid, tedizolid, sutezolid, and delpazolid against rapidly growing mycobacteria isolated in Beijing, China

BackgroundThe natural resistance of rapidly growing mycobacteria (RGM) to multiple antibiotics renders the treatment of the infections caused less successful. The objective of this study was to evaluate the in vitro susceptibilities of four oxazolidinones against different RGM species. MethodsThe microplate alamarBlue assay was performed to identify the minimum inhibitory concentrations (MICs) of four oxazolidinones – delpazolid, sutezolid, tedizolid, and linezolid – for 32 reference strains and 115 clinical strains of different RGM species. The MIC breakpoint concentration was defined as 16 μg/ml for linezolid. Next, the gene fragments associated with oxazolidinone resistance were amplified and sequenced, and mutations were defined in contrast with the sequences of the reference strains. ResultsTedizolid showed the strongest inhibitory activity against the Mycobacterium abscessus isolates. Delpazolid exhibited better antimicrobial activity against the Mycobacterium fortuitum isolates when compared to linezolid, with 4-fold lower MIC values. The protein alignment and structure-based analysis showed that there might be no correlation between oxazolidinone resistance and mutations in the rplC, rplD, and 23S rRNA genes in the tested RGM. ConclusionsTedizolid had the strongest inhibitory activity against M. abscessus in vitro, while delpazolid presented the best inhibitory activity against M. fortuitum. This provides important insights into the potential clinical application of oxazolidinones to treat RGM infections.

Disseminated Cutaneous Mycobacterium Fortuitum-Chelonae Complex Infection in a Young, Immunocompetent Patient: A Case Report

Mycobacteria fortuitum and chelonae are a group of Rapidly Growing Mycobacteria (RGM) that can cause skin infections, most commonly in immunocompromised patients. RGM can also infect immunocompetent patients, but the disease is usually localized. Immunocompetent patients infected by RGM usually had a predisposing condition leading to the skin infection. We present a case of an immunocompetent patient with no predisposing factors, who presented with a chronic lesion on his neck that disseminated to his axilla. Culture and species identification from the skin biopsy revealed Mycobacterium fortuitum-chelonae complex. The patient was treated with a combination of surgery and multi-drug therapy. This case report highlights the rarity of cutaneous RGM infections encountered in ENT setting and the diagnostic dilemma due to the non-typical characteristics of skin lesion in RGM infections.

Nationwide surveillance of antimicrobial susceptibility of 509 rapidly growing mycobacteria strains isolated from clinical specimens in Japan

This study aimed to identify effective treatments against rapidly growing mycobacteria (RGM) infections by investigating the minimum inhibitory concentrations (MIC) of 24 antimicrobial agents and their molecular mechanisms of resistance. In total, 509 clinical RGM isolates were identified by analyzing the sequences of three housekeeping genes (hsp65, rpoB, and sodA), and their susceptibilities to 24 antimicrobial agents were tested. We also performed sequencing analysis of antimicrobial resistance genes (rrl, rrs, gyrA, and gyrB). To identify Mycobacteroides abscessus group subspecies, we performed PCR-based typing and determined the sequevar of erm(41). We identified 15 RGM species, most of which were susceptible to amikacin and linezolid. Among these species, arbekacin and sitafloxacin had the lowest MIC among the same class of antimicrobials. The MIC of rifabutin for M. abscessus subsp. abscessus (MAB) was lower than that for M. abscessus subsp. massiliense (MMA). The proportion of MAB isolates with MIC ≤ 2 mg/L for rifabutin was significantly higher than that of MMA [MAB: 50/178 (28.1%) vs. MMA: 23/130 (17.7%); p = 0.041]. In summary, our study revealed the antimicrobial susceptibility profile of 15 RGM species isolated in Japan and indicated that arbekacin, sitafloxacin, and rifabutin may be possible therapeutic options for RGM infections.

Human environment around the world surrounded by rapidly growing mycobacteria (RGM)

Aims and Objective: The rapid growth of Mycobacteria (RGM) is a member of Non-tuberculous Mycobacterium that are environmental and opportunistic pathogens whose role in human disease is increasingly recognized. RGMs are highly found in various natural and man-made environmental resources. They can be opportunistically transmitted to humans through contaminated water sources and cause their infectious pulmonary and extrapulmonary infectious diseases. Misdiagnosis of this type of mycobacterium can lead to destructive results. As a result, improper treatment Faced with it can lead to recurrent infections as well as drug resistance. Methods: The aim of this study was to review the existing studies on the prevalence of RGMs between 1990-2017 in worldwide. Data on the prevalence of RGM infection were collected from databases such as PubMed, Web of Science, Cochrane Library, Embase, Scopus, and other scientific databases. Results: In Asia, 776 cases were reported. Among these, the M. furtuitum 23.32% (181,776), and M. chelonae 18.04%(140,776) were the most prevalence, respectively. Also, 105 cases reported in Africa, with the highest prevalence cases being M. fortuitum 46.67%(49,105), M. neoaurium 14.29%(15,105), and M. septicum 8.57% (9,150), respectively. On the other hand, 1363 cases were reported throughout Europe. Among these, the M. furtuitum 30.37% (414,1363), M. chelonae 18.86%(257,1363), and M. peregrinum 13.94%(190,1363) were the most prevalence, respectively. In the United States, 237 cases of RGM were reported, which the highest prevalence was related to the genus M. chelonae 25.32%(60,237), M. mucogenicum 23.63%(56,237) and M. furtuitum 22.36%(53,237), respectively. Also, in Australia 120 cases were observed, with the highest prevalence in M. fortuitum 49.17%(59,120), M. septicum 21.67%(26,120), and M. chelonae 8.33%(10,120), respectively. Conclusion: Given the increasing prevalence of RGMs in different environments, it seems necessary to implement more infection control strategies, appropriate diagnostic methods and control guidelines for NTM diseases. It can be said that we need to increase the quality of diagnostic reference methods and more accurate measures to prevent and control RGM infections.

Profiles of Extrapulmonary Nontuberculous Mycobacteria Infections and Predictors for Species: A Multicenter Retrospective Study.

Extrapulmonary nontuberculous mycobacteria (NTM) infections contribute to morbidity and mortality worldwide. However, studies about extrapulmonary NTM infections have been limited. Therefore, we aim to describe the diversity of extrapulmonary NTM infections and identify predictors for species. Information regarding diversity of NTM isolates, antimicrobial susceptibility testing, treatment regimens, and outcomes were collected from four tertiary care centers in South Korea. Comparisons were made between patients with rapidly growing mycobacteria (RGM) and slowly growing mycobacteria (SGM) infections. A total of 117 patients (46 males vs. 71 females) were included. Skin and soft tissue infections (SSTIs) predominated (34.2%), followed by bone and joint infections (28.2%). In SSTIs, RGM species were predominantly identified (26/28, 92.9%), whereas SGM species were mainly identified in bone and joint infections (18/26, 69.2%), and the difference of isolated sites was verified by a post hoc test (p < 0.001). Multivariable regression analysis revealed that male sex (vs. female sex; OR 5.30, CI 1.35–24.26, p = 0.020) and bone and joint infections (vs. SSTIs; OR 18.10, CI 3.28–157.07, p = 0.002) were predictors of SGM infections, whereas the opposite was observed for RGM infections. Bone and joint infections and male sex were predictors for SGM infections, whereas SSTIs and female sex were predictors for RGM infections.

Nontuberculous mycobacterial infection in a tertiary care center in Mexico, 2001–2017

IntroductionNontuberculous mycobacteria (NTM) comprise several pathogens with a complex profile of virulence, diverse epidemiological and clinical patterns as well as host specificity. Recently, an increase in the number of NTM infections has been observed; therefore, the objective of this study was to evaluate the clinical characteristics and outcomes of these infections. MethodsWe included patients with NTM infections between 2001–2017 and obtained risk factors, clinical features and outcomes; finally, we compared this data between slowly growing (SGM) and rapidly growing mycobacteria (RGM). ResultsA total of 230 patients were evaluated, 158 (69%) infected and 72 (31%) colonized/pseudoinfected. The average annual incidence in the first 11 years of the study was 0.5 cases per 1000 admissions and increased to 2.0 cases per 1000 admissions later on. The distribution of NTM infections was as follows: bloodstream and disseminated disease 72 (45%), lung infection 67 (42%), skin and soft tissue infection 19 (12%). Mycobacterium avium complex was the most common isolate within SGM infections, and HIV-infected patients were the most affected. Within RGM infections, M. fortuitum was the most common isolate from patients with underlying conditions such as cancer, type-2 diabetes mellitus, presence of invasive devices, and use of immunosuppressive therapy. We did not find significant differences in deaths and persistent infections between disseminated SGM infection when compared to disseminated RGM infection (42% vs. 24%, p=0.22). However, disseminated SGM infection required a longer duration of therapy than disseminated RGM infection (median, 210 vs. 42 days, p=0.01). NTM lung disease showed no significant differences in outcomes among treated versus non-treated patients (p=0.27). ConclusionsOur results show a significant increase in the number of Non-tuberculosis-mycobacteria infections in our setting. Patients with slow-growing-mycobacteria infections were mainly persons living with human immunodeficiency virus . Older patients with chronic diseases were common among those with rapidly-growing-mycobacteria infections. For non-tuberculosis-mycobacteria lung infection, antibiotic therapy should be carefully individualized.

An overview of pulmonary infections due to rapidly growing mycobacteria in South Asia and impressions from a subtropical region.

Rapidly growing mycobacteria (RGM) comprise nearly half of the validated species of nontuberculous mycobacteria (NTM) and have been reported to have a higher incidence in Asia as compared to Europe and America. There is limited information on RGM infections from South Asia. Hence, the present study aimed to ascertain the incidence of pulmonary infections due to RGM in Delhi and to review the status of available information on the prevalence of RGM in South Asia, a region endemic for tuberculosis. We analyzed 933 mycobacterial isolates obtained from pulmonary samples in Delhi and performed species identification by polymerase chain reaction (PCR)-restriction analysis (restriction fragment length polymorphism) and line probe assay. Drug susceptibility testing (DST) was performed by broth microdilution method. We also reviewed reports available on pulmonary infections in South Asia, attributed to RGM. Of the 933 mycobacterial isolates studied, NTM were identified in 152 (16.3%). Of these, 65/152 (42.8%) were RGM comprising Mycobacterium fortuitum (34/65; 52.3%), Mycobacterium abscessus (25/65; 38.5%), Mycobacterium chelonae (3/65; 4.61%), Mycobacterium mucogenicum (2/65; 3.1%), and Mycobacterium smegmatis (1/65; 1.5%). On applying the American Thoracic Society/Infectious Diseases Society of America guidelines, 11/25 (44%) M. abscessus, 3/3 (100%) M. chelonae, and both isolates of M. mucogenicum were found to be clinically relevant. DST revealed that maximum susceptibility of the RGM was seen to linezolid, clarithromycin, and amikacin. Of the RGM isolated in the present study, 16/65 (24.6%) were found to be clinically relevant. Hence, it is important to recognize these organisms as potential pathogens to identify patients with RGM disease to initiate appropriate therapy.

1358. A Novel Rapidly Growing Mycobacteria (RGM) Species Causing Soft Tissue and Orthopedic Hardware Infection After Trauma

BackgroundThe widespread use of molecular techniques has resulted in increasing numbers of newly characterized rapidly growing mycobacteria (RGM). Many RGM cause soft tissue and orthopedic hardware infection, particularly after trauma. RGM species identification remains challenging with few genetic differences between species.MethodsWe describe a case involving RGM. We report results of matrix-assisted laser desorption/ionization time of flight (MALDI-TOF) mass spectrometry (Bruker Biotyper), sequencing of rpoB, erm(39), and 16S rRNA genes, and antibiotic susceptibility testing (AST). We review previous reports describing similar RGM infections.ResultsA 58-year-old male sustained multiple fractures and right thigh compartment syndrome after a motorcycle accident. He underwent fasciotomy and multi-stage surgical fixations. 3 months later, he had wound dehiscence, purulence and multiple fluid collections of his right leg and knee requiring surgical drainage and removal of orthopedic hardware. After 4 days, acid-fast bacilli grew on routine bacterial culture media. MALDI-TOF identified the isolate as Mycobacterium mageritense. In contrast, sequencing of 16S rRNA (100% identity) and erm(39) (> 99% identity) identified the isolate as Mycobacterium houstonense; erm(39) only had 80% similarity with Mycobacterium fortuitum. Sequencing of rpoB showed a 19 bp difference with the M. houstonense type strain, and showed similarity to M. fortuitum (97.64%) than M. houstonense (97.45%). AST demonstrated resistance to clarithromycin only. After initial treatment with imipenem, ciprofloxacin, and doxycycline, definite therapy with ciprofloxacin and doxycycline was successful. In the literature, we found one case each of M. mageritense and M. houstonense infection after trauma.ConclusionThis case highlights the importance of RGM other than M. fortuitum as a cause of soft tissue and orthopedic hardware infections, and illustrates the difficulty of identifying them to the species level. Sequencing of erm(39) and 16S rRNA gene identified the isolate as M. houstonense, but the larger difference (>2.5%) in rpoB sequence suggests a novel species. Further characterization is underway. Efforts to determine RGM species and antibiotic susceptibility give important insight into diagnosis and management.Disclosures All authors: No reported disclosures.

782. Risk Factors, Clinical Characteristic, and Treatment Outcomes for Nontuberculous Mycobacterial Disease in Mexico

BackgroundNontuberculous Mycobacteria (NTM) cause diverse clinical manifestations in multiples clinical setting, and in the past years, there has been an increasing prevalence and variability among geographic regions, this associated with a diversity of hosts and clinical manifestations. We objective was evaluated the clinical and microbiologic characteristic, and the treatment outcomes related to slowly growing mycobacteria (SGM) and rapidly growing mycobacteria (RGM).MethodsWhen conducting a retrospective study between January 2001 and December 2017, retrospectively their medical records were reviewed for obtainments of site of isolation or infection, comorbidities or predisponent condition, clinical and radiographic presentation, and treatment outcomes.ResultsA total of 90 patients with isolated of RGM and 87 within SGM were evaluated among these M. avium and M. fortuitum were the most predominant species. HIV infection was the predominat risk factor for SGM infections (P < 0.001); the conditions associated to RGM infections were cancer (P = 0.02787); diabetes mellitus (DM) (P = 0.01418), chronic kidney disease (CKD)(P = 0.04662), use of immunosuppressive medication (P < 0.001), and use of invasive device only were present in the RGM group. In the RGM group, lung infection was the most common site of infection (43%); in the SGM group, the disseminated disease was the most common (54%). The time of treatment was more prolonged in the SGM group (196 vs. 229 days, P = 0.0309). In the RGM group, the rate of cure was higher in the subgroup of Mycobacterial stream infections and disseminated disease (15 vs. 5, P = 0.0146). In the analysis of lung infection who meet the IDSA/ATS criteria were divided into the group with treatment and the group without treatment, the outcomes were not significative in both groups.ConclusionThe NTM infections are an important cause of disease in patients with chronic conditions such as cancer, immunosuppressive medication, CKD, use of invasive device, and DM. HIV infection persist as the first risk factor for M. avium disseminated disease, the treatment for this latter condition in spite of more prolonged, it had a lower rate of cure. The treatment of lung infections for NTM must be individualized although the IDSA/ATS criteria are met.Disclosures All authors: No reported disclosures.

TB, OR NOT TB, THAT IS THE QUESTION: LARGE BILATERAL CAVITARY LESIONS IN THE LUNG FROM A CLEVER MYCOBACTERIUM TUBERCULOSIS MIMIC

SESSION TITLE: Chest Infections 3 SESSION TYPE: Med Student/Res Case Rep Postr PRESENTED ON: 10/09/2018 01:15 PM - 02:15 PM INTRODUCTION: Rapidly growing mycobacteria (RGM) are a group of non-tuberculous mycobacteria. M. abscessus complex group (MAG: subsp. abscessus, bolletii and massiliense) is ubiquitous in soil and water and makes up 80% of pulmonary RGM infections. Patients with bronchiectasis, cystic fibrosis and prior tuberculosis are most affected. Cavitary lesions make up 16-42% of radiological findings. MAG is slowly progressive but can prove fatal due to respiratory failure with a 15% mortality rate when treated with combination antibiotic regimens with or without surgery. CASE PRESENTATION: A 53 year old male presented to the ER from his doctor’s office with tachycardia for 1 hour. He had had dry cough and weight loss of 20 lbs over 2 months. PMH: HIV, alcoholic liver disease, hypertension. On exam: BP:101/56 mmHg, HR:179/min, RR:18/min, T:98.7˚F and O2 Sat: 98% on room air. He had scleral icterus, hepatomegaly, abdominal distension and pedal edema. EKG showed SVT which was managed with adenosine. WBC:12,000/cu mm, Alk. Phos:351 IU/L, AST:74 IU/L, ALT:18 IU/L, Total Bilirubin:5.1 mg/dl, Cr:0.66 mg/dl, INR:2.1, CD4:473. CT Chest: large cavitary lesions measuring 6 and 4 cm in bilateral lung apices, with reticulonodular and tree-in-bud opacities. Sputum culture grew acid-fast bacilli in 2 samples. Quantiferon Gold:negative. Isoniazid, rifampin, pyrazinamide and ethambutol were started. Sputum PCR was negative for M.Tuberculosis and MAC with negative morphology for M. gordonae. M. kansasii was considered, so pyrazinamide was discontinued. Liver function worsened. 12 days after admission, M. abscessus was isolated from sputum. Rifampin, isoniazid and ethambutol were discontinued. Oral azithromycin and IV amikacin were started with plan to transition to oral antibiotics in 2 weeks, with total 12 months of therapy. DISCUSSION: While M. tuberculosis and M. kansasii were differentials in our patient with bilateral pulmonary cavitary lesions, a diagnosis of M. abscessus is a reminder to consider this potentially fatal condition that has nuanced management in these patients. CONCLUSIONS: Sputum samples should be acquired swiftly to allow differentiation between M. TB and MAG, as public health surveillance requirements for tuberculosis do not apply to MAG. MAG is resistant to antituberculous drugs and unnecessary treatments with them increases risk for hepatotoxicity, as in our patient. Identification of MAG subspecies has implications too, because subspecies abscessus and bolletii have an active erm gene that causes resistance to macrolides but they are usually susceptible to IV amikacin, cefoxitin and tigecycline. Informing the laboratory of possible MAG allows timely identification by specialized methods. Reference #1: Lee, M.-R., Sheng, W.-H., Hung, C.-C., Yu, C.-J., Lee, L.-N., & Hsueh, P.-R. (2015). Mycobacterium abscessus Complex Infections in Humans. Emerging Infectious Diseases, 21(9), 1638–46. https://doi.org/10.3201/2109.141634 DISCLOSURES: No relevant relationships by Carlos Marin Ramirez, source=Web Response No relevant relationships by Mariam Mir, source=Web Response No relevant relationships by Diana Miranda Ruiz, source=Web Response No relevant relationships by Nehan Sher, source=Web Response No relevant relationships by Siddharthan Vaithilingam, source=Web Response

Rapidly growing Mycobacterium infections after cosmetic surgery in medical tourists: the Bronx experience and a review of the literature

BackgroundMedical tourism is increasingly popular for elective cosmetic surgical procedures. However, medical tourism has been accompanied by reports of post-surgical infections due to rapidly growing mycobacteria (RGM). The authors’ experience working with patients with RGM infections who have returned to the USA after traveling abroad for cosmetic surgical procedures is described here. MethodsPatients who developed RGM infections after undergoing cosmetic surgeries abroad and who presented at the Montefiore Medical Center (Bronx, New York, USA) between August 2015 and June 2016 were identified. A review of patient medical records was performed. ResultsFour patients who presented with culture-proven RGM infections at the sites of recent cosmetic procedures were identified. All patients were treated with a combination of antibiotics and aggressive surgical treatment. ConclusionsThis case series of RGM infections following recent cosmetic surgeries abroad highlights the risks of medical tourism. Close monitoring of affected patients by surgical and infectious disease specialties is necessary, as aggressive surgical debridement combined with appropriate antibiotic regimens is needed to achieve cure. Given the increasing reports of post-surgical RGM infections, consultants should have a low threshold for suspecting RGM, as rapid diagnosis may accelerate the initiation of targeted treatment and minimize morbidity.

Antimicrobial susceptibility testing of rapidly growing mycobacteria isolated in Japan

BackgroundDifficult-to-treat infections caused by rapidly growing mycobacteria (RGM) are increasingly observed in clinical settings. However, studies on antimicrobial susceptibilities and effective treatments against RGM in Japan are limited.MethodsWe conducted susceptibility testing of potential antimicrobial agents, including tigecycline and tebipenem, against RGM. Clinical RGM isolates were collected from a university hospital in Japan between December 2010 and August 2013. They were identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and the sequencing of 16S rRNA, rpoB, and hsp65 genes. The samples were utilized for susceptibility testing using 16 antimicrobials, with frozen broth microdilution panels.ResultsForty-two isolates were obtained: 13, Mycobacterium abscessus complex; 12, Mycobacterium chelonae; 9, Mycobacterium fortuitum; and 8, M. fortuitum group species other than M. fortuitum. Different antimicrobial susceptibility patterns were observed between RGM species. Clarithromycin-susceptible strain rates were determined to be 0, 62, and 100% for M. fortuitum, M. abscessus complex, and M. chelonae, respectively. M. abscessus complex (100%) and >80% M. chelonae isolates were non-susceptible, while 100% M. fortuitum group isolates were susceptible to moxifloxacin. Linezolid showed good activity against 77% M. abscessus complex, 89% M. fortuitum, and 100% M. chelonae isolates. Regardless of species, all tested isolates were inhibited by tigecycline at very low minimal inhibitory concentrations (MICs) of ≤0.5 μg/mL. MICs of tebipenem, an oral carbapenem, were ≤4 μg/mL against all M. fortuitum group isolates.ConclusionsOur study demonstrates the importance of correct identification and antimicrobial susceptibility testing, including the testing of potential new agents, in the management of RGM infections.

Susceptibility of rapidly growing mycobacteria isolated from Australian cats to ivermectin, moxidectin, ceftiofur and florfenicol.

Rapidly growing mycobacteria (RGM) infections in cats typically manifest as a panniculitis, requiring long-term antimicrobial therapy for resolution. The search for novel antimicrobial therapies to reduce treatment duration and improve the rate of clinical resolution is imperative. Accordingly, RGM isolates underwent susceptibility testing to some avermectins and other antibacterial drugs currently available. Five Mycobacterium fortuitum and six Mycobacterium smegmatis isolates obtained from Australian cats underwent susceptibility testing by microbroth dilution to ivermectin, moxidectin, ceftiofur and florfenicol. All isolates were resistant to the highest concentrations of ivermectin, moxidectin and ceftiofur tested (1024 µg/ml, 256 μg/ml and 32 μg/ml, respectively). All isolates of M fortuitum were resistant to the highest concentration of florfenicol tested (128 µg/ml). The minimum inhibitory concentration range of florfenicol that inhibited growth of M smegmatis isolates was 32-64 µg/ml. All drugs appear to have no efficacy in vitro for the treatment of RGM infections.