Mycobacterium Avium Complex Isolates Research Articles

Characteristics of pulmonary Mycobacterium avium complex disease diagnosed later in follow-up after negative mycobacterial study including bronchoscopy

BackgroundWe occasionally experience cases suspected of pulmonary Mycobacterium avium complex (MAC) disease without positive bacterial cultures. ObjectiveTo evaluate features of pulmonary MAC cases diagnosed later in the follow-up after negative intensive investigation. MethodsWe defined and compared three groups; the first study negative (FSN) group, the first study positive (FSP) group, and MAC negative group. The FSN group consisted of patients negative for MAC isolation by bronchial washing performed between 2007 and 2011, but positive later. Patients with positive MAC cultures in the first study were incorporated into the FSP group. MAC negative group consisted of MAC suspects without MAC isolation in the follow-up. ResultsTwenty-four patients were classified as FSN group, 61 as MAC negative group and 265 as FSP group. FSN group exhibited more solitary nodule pattern (n = 7 in FSN, n = 6 in FSP; p < 0.001) and less nodular/bronchiectatic (NB) diseases (n = 17 in FSN, n = 245 in FSP; p < 0.001). When limited to NB type, the FSP group had more cavitations (6% in FSN, 32% in FSP; p = 0.028). Patients with more than three lung lobes involved were more frequent in the FSN group compared with FSP group with negative sputum cultures (65% vs 34%; p = 0.014) and with MAC negative group (65% vs 28%; p = 0.009). ConclusionsPatients diagnosed as pulmonary MAC disease in the follow-up duration tend to show solitary nodular pattern or NB pattern without cavitation. In FSN patients with NB pattern, more lung lobes were involved in the first study, suggesting subsequent MAC infection onto the underlying ectatic bronchi.

Evaluation of Vitek MS for rapid classification of clinical isolates belonging to Mycobacterium avium complex

We evaluated the ability of the Vitek MS system to classify clinical pulmonary Mycobacterium avium complex isolates compared to multilocus sequence analysis. Vitek MS accurately identified 55% of the isolates as M. avium and 18% as M. intracellulare, but misidentified 24 (27%) Mycobacterium chimaera isolates as Mycobacterium intracellulare.

Macrolide/Azalide Therapy for Nodular/Bronchiectatic Mycobacterium avium Complex Lung Disease

There is no large study validating the appropriateness of current treatment guidelines for Mycobacterium avium complex (MAC) lung disease. This is a retrospective single-center review evaluating the efficacy of macrolide/azalide-containing regimens for nodular/bronchiectatic (NB) MAC lung disease. Patients were treated according to contemporary guidelines with evaluation of microbiologic responses. Macrolide susceptibility of MAC isolates was done at initiation of therapy, 6 to 12 months during therapy, and on the first microbiologic recurrence isolate. Microbiologic recurrence isolates also underwent genotyping for comparison with the original isolates. One hundred eighty patients completed > 12 months of macrolide/azalide multidrug therapy. Sputum conversion to culture negative occurred in 154 of 180 patients (86%). There were no differences in response between clarithromycin or azithromycin regimens. Treatment regimen modification occurred more frequently with daily (24 of 30 [80%]) vs intermittent (2 of 180 [1%]) therapy (P = .0001). No patient developed macrolide resistance during treatment. Microbiologic recurrences during therapy occurred in 14% of patients: 73% with reinfection MAC isolates, 27% with true relapse isolates (P = .03). Overall, treatment success (ie, sputum conversion without true microbiologic relapse) was achieved in 84% of patients. Microbiologic recurrences occurred in 74 of 155 patients (48%) after completion of therapy: 75% reinfection isolates, 25% true relapse isolates. Current guidelines for macrolide/azalide-based therapies for NB MAC lung disease result in favorable microbiologic outcomes for most patients without promotion of macrolide resistance. Intermittent therapy is effective and significantly better tolerated than daily therapy. Microbiologic recurrences during or after therapy are common and most often due to reinfection MAC genotypes.

Recurrence of pulmonary Mycobacterium avium complex disease due to endogenous reactivation

Introduction: An official American Thoracic Society and Infectious Disease Society of America statement has shown that patients with pulmonary Mycobacterium avium complex (MAC) disease who complete 10–12 months of negative cultures on therapy but then have either single or multiple positive MAC cultures are more likely to have reinfection with a new MAC strain. Case presentation: A 63‐year‐old woman was diagnosed with pulmonary disease caused by clarithromycin (CAM)‐susceptible MAC. Before initiating chemotherapy using a four‐drug regimen containing CAM, an investigation of the patient’s residential bathroom was conducted and one of the M. avium isolates recovered from the bathtub inlet was found to be genetically identical to sputum‐derived isolates by variable number tandem repeats analysis using M. avium tandem repeat loci (MATR‐VNTR). A second investigation of the bathroom during chemotherapy showed no M. avium isolates, and five consecutive sputum cultures were negative for 12 months until chemotherapy was discontinued. A recurrence occurred 3 months after the end of chemotherapy (at age 65 years). A third investigation of the bathroom was performed and MATR‐VNTR analysis revealed that the VNTR profile of the M. avium isolates recovered from the sputum at recurrence was identical to that of the isolates recovered from the sputum at initial diagnosis and the bathroom at the first investigation. Conclusion: The recurrence occurred due to endogenous reactivation of the initial M. avium isolate despite drug treatment for 12 months after sputum culture conversion. Further genetic analyses of MAC isolates recovered from patients and environments should be encouraged.

In Vitro Activity of Amikacin against Isolates of Mycobacterium avium Complex with Proposed MIC Breakpoints and Finding of a 16S rRNA Gene Mutation in Treated Isolates

<i>In Vitro</i> Activity of Amikacin against Isolates of Mycobacterium avium Complex with Proposed MIC Breakpoints and Finding of a 16S rRNA Gene Mutation in Treated Isolates

In Vitro Activity of Amikacin against Isolates of Mycobacterium avium Complex with Proposed MIC Breakpoints and Finding of a 16S rRNA Gene Mutation in Treated Isolates

Amikacin is a major drug used for the treatment of Mycobacterium avium complex (MAC) disease, but standard laboratory guidelines for susceptibility testing are not available. This study presents in vitro amikacin MICs for 462 consecutive clinical isolates of the MAC using a broth microdilution assay. Approximately 50% of isolates had amikacin MICs of 8 μg/ml, and 86% had MICs of ≤16 μg/ml. Of the eight isolates (1.7%) with MICs of 64 μg/ml, five had an MIC of 32 μg/ml on repeat testing. Ten isolates (2.1%) had an initial amikacin MIC of >64 μg/ml, of which seven (1.5%) had MICs of >64 μg/ml on repeat testing. These seven isolates had a 16S rRNA gene A1408G mutation and included M. avium, Mycobacterium intracellulare, and Mycobacterium chimaera. Clinical data were available for five of these seven isolates, all of which had received prolonged (>6 months) prior therapy, with four that were known to be treated with amikacin. The 16S mutation was not detected in isolates with MICs of ≤64 μg/ml. We recommend primary testing of amikacin against isolates of the MAC and propose MIC guidelines for breakpoints that are identical to the CLSI guidelines for Mycobacterium abscessus: ≤16 μg/ml for susceptible, 32 μg/ml for intermediate, and ≥64 μg/ml for resistant. If considered and approved by the CLSI, this will be only the second drug recommended for primary susceptibility testing against the MAC and should facilitate its use for both intravenous and inhaled drug therapies.

The Pharmacokinetics and Pharmacodynamics of Pulmonary Mycobacterium avium Complex Disease Treatment

Currently recommended multidrug treatment regimens for Mycobacterium avium complex (MAC) lung disease yield limited cure rates. This results, in part, from incomplete understanding of the pharmacokinetics and pharmacodynamics of the drugs. To study pharmacokinetics, pharmacodynamics, and drug interactions of multidrug treatment regimens in a large cohort of patients with MAC lung disease. We retrospectively collected pharmacokinetic data of all patients treated for MAC lung disease in the Adult Care Unit at National Jewish Health, Denver, Colorado, in the January 2006 to January 2010 period; we retrospectively calculated areas under the time-concentration curve (AUC). Minimum inhibitory concentrations (MIC) of their MAC isolates were retrieved for pharmacodynamic calculations. We included 531 pharmacokinetic analyses, performed for 481 patients (84% females; mean age, 63 yr; mean body mass index, 21.6). Peak serum concentrations (C(max)) below target range were frequent for ethambutol (48% of patients); clarithromycin (56%); and azithromycin (35%). Concurrent administration of rifampicin led to 68%, 23%, and 10% decreases in C(max) of clarithromycin, azithromycin, and moxifloxacin. C(max)/MIC or AUC/MIC ratios associated with bactericidal activity were seldom met; 57% of patients achieved target ratios for ethambutol, versus 42% for clarithromycin, 19% for amikacin, 18% for rifampicin, and 11% for moxifloxacin. Currently recommended regimens for MAC lung disease yield important pharmacologic interactions and low concentrations of key drugs including macrolides. Pharmacodynamic indices for rifampicin, clarithromycin, amikacin, and moxifloxacin are seldom met. This may partly explain the poor outcomes of currently recommended treatment regimens. Trials of new drugs and new dosing strategies are needed.

Isolation and identification of Mycobacterium avium complex and other nontuberculosis mycobacteria from drinking-water in Basra governorate, Iraq

This study aimed to determine the occurrence of Mycobacterium avium complex and other nontuberculous mycobacteria in drinking-water in Basra governorate, Iraq and their susceptibility to several antibiotics and the effect of 0.5 mg/L of chlorine on their survival. A total of 404 samples of drinking-water were collected from 33 different districts of the governorate from November 2006 to August 2007. Filtered samples were incubated for 7 days or less in a monophasic-biphasic culture setup of tuberculosis broth and Lowenstein-Jensen agar. The 252 isolates were identified as M. avium complex (21), M. marinum (15), M. kansasii (30), M. simiae (20), M. szulgai (19), M. xenopi (16), M. malmoense (11), M. fortuitum (37), M. chelonae (50) and M. abscessus (33). Isolates were tested for antibiotic susceptibility as well as their ability to tolerate chlorine at a concentration of 0.5 mg/L. The presence of these pathogenic bacteria in drinking-water renders the water unfit for human consumption.

Aging, COPD, and Other Risk Factors Do Not Explain the Increased Prevalence of Pulmonary Mycobacterium avium Complex in Ontario

The cause of observed increases in pulmonary Mycobacterium avium complex (pMAC) isolation and disease is unexplained. To explore possible causes of the increase in pMAC isolation and disease prevalence in Ontario, Canada, we studied age and other population-level risk factors. We determined age and sex of patients with pMAC disease between 2003 and 2008. We then estimated whether the potential effect of population aging and changes in prevalence of HIV infection, solid organ transplant, COPD, and tumor necrosis factor-α (TNF-α) inhibition have contributed to the observed increase in pMAC disease. During 2003 to 2008, pMAC isolation and disease prevalence (per 100,000) both increased (8.44 to 12.62 and 4.35 to 6.81, respectively). The total number of cases of disease increased by 348 (2.46 per 100,000). Based on actual contemporary population changes, aging could explain 70 additional cases (increase of 0.57 per 100,000). The increase in self-reported COPD prevalence could potentially explain 11 (95% CI, 0-42) additional cases (increase of 0.09 per 100,000 [95% CI, 0-0.34 per 100,000]). HIV infection, solid organ transplant, and TNF-α inhibition combined could potentially explain no more than 73 additional cases (increase of 0.60 per 100,000). Although population aging appears to be a major risk factor, the increase in pMAC disease in Ontario could be only partly explained by aging, increases in COPD, HIV, solid organ transplantation, and TNF-α inhibition therapy. The increase in pMAC is likely multifactorial and may be affected by environmental or pathogen factors not addressed in this study.

Clinical significance of Mycobacterium avium complex isolates at a medical center in northern Taiwan

We read with great interest the case report by Shen et al1 in the July 2010 issue of Journal of the Formosan Medical Association. In that retrospective study, the authors described the clinical significance of Mycobacterium avium complex (MAC) that had been isolated from respiratory specimens at a medical center in southern Taiwan. We wonder whether similar findings could be noted in other parts of Taiwan. Therefore, we would like to report our observation about nontuberculous mycobacteria (NTM) in northern Taiwan. From January to December 2009, a total of 1,756 specimens from 898 patients positive for NTM were identified at the Mycobacteriology Laboratory at the National Taiwan University Hospital, a 2,500-bed tertiary care center in northern Taiwan that receives more than 6,000 daily clinical visits. The most common NTM isolates identified were MAC (579 isolates from 279 patients), followed by Mycobacterium abcesssus (275 isolates from 174 patients), and Mycobacterium fortuitum (258 isolates from 186 patients). Among the 279 patients from whom MAC was isolated, MAC colonization was noted in 210 (75.3%) patients, and MAC caused NTM disease in 69 (24.7%) patients, based on the 2007 criteria of the American Thoracic Society/Infectious Diseases Society of America.2 Those findings were consistent with those from our previous study conducted during the period January 2000 to December 2008 at the same institution.3 In that study, a total of 9,204 NTM isolates were recovered from 4,786 patients, and 2,761 isolates from 1,515 patients were confirmed to be MAC. Among those patients, MAC colonization was noted in 1,282 (84.6%) and MAC caused NTM diseases in 233 (15.4%). The annual prevalence of MAC colonization ranged from 80.0% (2000) to 87.4% (2006). These findings are consistent with those reported by Shen et al,1 namely that only 12 (22.2%) of 54 patients with positive MAC isolates had clinically significant MAC pulmonary disease. In addition, trend analysis has revealed that the annual incidence (per 100,000 inpatients and outpatients) of MAC colonization increased

Diversity of Mycobacterium avium subsp. hominissuis mycobacteria causing lymphadenitis, France

The knowledge of Mycobacterium avium complex (MAC) genotypes responsible for lymphadenitis is limited. We retrospectively characterized all of the MAC isolates made in our laboratory in the last 18 years by sequence-based identification and genotyping, and compared the clinical and laboratory data for lymphadenitis-associated and non-lymphadenitis-associated MAC isolates. Of 67 MAC-infected patients, 25 lymphadenitis patients were significantly younger than 42 non-lymphadenitis patients, while the male/female ratio did not significantly differ between the two groups. Cervical topography found in 76.5% of lymphadenitis patients was significantly more frequent in non-immunocompromised patients (p=0.04). M. avium subsp. hominissuis was identified in 53 patients (24 lymphadenitis, 29 non-lymphadenitis), M. colombiense in six patients (five non-lymphadenitis, one lymphadenitis), M. intracellulare in four non-lymphadenitis patients, and M. chimaera in three non-lymphadenitis patients, while negative controls remained negative. M. hominissuis was significantly associated with lymphadenitis (p=0.03). M. hominissuis isolates yielded 15 genotypes in 29 non-lymphadenitis isolates (molecular diversity, 0.622) versus 11 genotypes in 24 lymphadenitis isolates (molecular diversity, 0.578), demonstrating a non-significant lower diversity of M. hominissuis isolates cultured from lymphadenitis. The genotypes did not correlate with the clinical features. These data suggest the presence of several environmental reservoirs for M. hominissuis causing lymphadenitis in France.

Clinical significance and antibiotic susceptibilities of nontuberculous mycobacteria from patients in Crete, Greece

To describe the clinical significance and antibiotic susceptibilities of nontuberculous mycobacteria (NTM) isolated from patients in Crete, Greece between January 2000 and December 2009. NTM identification was performed using conventional bacteriological methods and confirmed by molecular characterization with commercially available assays. Rare and novel species were identified by sequencing of the 16SrRNA and of the hsp65 genes. Antibiotic susceptibility testing was performed by E-test. Rapidly growing (RGM) and slowly growing (SGM) NTM were tested against 14 antimicrobials, including nine common ones, except for Mycobacterium avium and Mycobacterium intracellulare (MAC) complex isolates that were tested only against azithromycin, clarithromycin, linezolid and moxifloxacin. During the study period, 290 positive samples for NTM were recovered from 207 patients. Among the positive samples, 150 were identified as SGM and 57 as RGM. Overall, 50 patients met American Thoracic Society criteria for disease due to NTM, 42 by SGM and eight by RGM. Risk factors in patients with NTM disease were underlying lung diseases, mainly chronic obstructive pulmonary disease and asthma, smoking, rheumatoid arthritis, AIDS, alcohol or drug abuse, malignancies and bronchiectasis. The most common disease-causing species were the MAC complex (n = 25) followed by Mycobacterium kansasii (n = 10). Amikacin was the most active drug for RGM with 100% susceptibility. Macrolides were very active against isolates of the MAC complex, while tigecycline had excellent activity in vitro against RGM. M. kansasii was the most susceptible NTM species in vitro. Our study is the first to describe the clinical significance, risk factors and susceptibility patterns of NTM isolates in a Greek population.

Isolation of Mycobacterium avium complex from the "24-hour bath"

The "24-HOUR BATH" is an apparatus which circulates the bath water, keeps it clean and warm, and makes it possible to take a bath at any time during the day or night. It consists of apparatus for cleaning (sponge or mesh filter and filter material), heating (ceramic heater), and sterilizing (UV lamp). Recently, three cases of skin disease due to M. avium infection in private homes, in which "24-HOUR BATH" water was suspected to be the source of infection, have been reported. We attempted to isolate M. avium complex from the water (32 specimens), sponge filter (29 specimens), and filter material (32 specimens) of the "24-HOUR BATH". One hundred-ml samples of bath water, and 50-ml samples of rinse from a sponge filter or filter material were centrifuged at 3000 rpm for 20 min. Sediment was suspended in distilled water and a smear was prepared, and then digested and decontaminated with 2% sodium hydroxide. The processed specimens were cultured on 2% Ogawa medium containing ofloxacin (1 microgram/ml) and ethambutol (2.5 micrograms/ml) for 8 weeks at 37 degrees C. Positive smears were 3 (9.4%), 25 (86.2%) and 25 (78.1%) specimens from the water, sponge and filter material, respectively. A few bacterial clumps were observed, especially in the sponge specimens. The number of positive culture was 5 (15.6%), 24 (82.8%) and 25 (78.1%) from the water, sponge and filter material, respectively. Among them the number of Runyon's Group III-positive cultures was 5 (100%), 22 (91.7%) and 20 (80%) in the water, sponge, and filter material specimens, respectively. In most cases, cultures were positive for both the sponge and filter material specimens. All of the Group III mycobacteria were smooth, grew at 28, 37, 42, and 45 degrees C, negative for niacin, nitrate reductase, semiquantitative catalase, urease and Tween80 hydrolysis, and positive for 68 degrees C catalase. All of the strains reacted with M. avium complex AccuProbe and M. avium AccuProbe, but none of the strains reacted with M. intracellulare AccuProbe. Therefore, all the Group III isolates were identified as M. avium by the culture, biochemical and genetical characteristics.

Evaluation of a rapid detection method of clarithromycin resistance genes in Mycobacterium avium complex isolates

Clarithromycin is the key drug in the various treatment regimens of Mycobacterium avium complex (MAC) diseases, and is the only drug for which drug susceptibility has been shown to correlate with clinical response in these diseases. A point mutation at either positions 2058 or 2059 of the 23S rRNA gene has been reported to occur in high-level clarithromycin-resistant isolates. In this study, we examined the correlation between the results from a drug susceptibility test and the mutation of the 23S rRNA gene involved in drug resistance in MAC. Furthermore, we adapted a rapid detection method using amplification refractory mutation system (ARMS)-PCR to identify mutations in the 23S rRNA gene in MAC isolates. Using a microdilution method based on the NCCLS/CLSI recommendation, the MIC of clarithromycin was determined for 245 clinical MAC isolates. Of these, 219 clarithromycin-susceptible and 26 clarithromycin-resistant strains were analysed by sequencing of the 23S rRNA gene and ARMS-PCR. The drug susceptibility test revealed a bimodal distribution of MICs for both the susceptible and resistant strains. Sequence analysis of the 23S rRNA gene revealed that all of the clarithromycin-susceptible strains were wild-type whereas 24 of the clarithromycin-resistant strains were mutant type. The sensitivity of the sequence and ARMS-PCR analyses was 92.3% and 84.6%, respectively, and the specificity of both was 100%. We found a correlation between MICs of clarithromycin and 23S rRNA gene mutations. ARMS-PCR for 23S rRNA mutations of MAC isolates is useful for rapid detection of clarithromycin resistance.

Efficient Differentiation ofMycobacterium aviumComplex Species and Subspecies by Use of Five-Target Multiplex PCR

Infections caused by the Mycobacterium avium complex (MAC) are on the rise in both human and veterinary medicine. A means of effectively discriminating among closely related yet pathogenetically diverse members of the MAC would enable better diagnosis and treatment as well as further our understanding of the epidemiology of these pathogens. In this study, a five-target multiplex PCR designed to discriminate MAC organisms isolated from liquid culture media was developed. This MAC multiplex was designed to amplify a 16S rRNA gene target common to all Mycobacterium species, a chromosomal target called DT1 that is unique to M. avium subsp. avium serotypes 2 and 3, to M. avium subsp. silvaticum, and to M. intracellulare, and three insertion sequences, IS900, IS901, and IS1311. The pattern of amplification results allowed determination of whether isolates were mycobacteria, whether they were members of the MAC, and whether they belonged to one of three major MAC subspecies, M. avium subsp. paratuberculosis, M. avium subsp. avium, and M. avium subsp. hominissuis. Analytical sensitivity was 10 fg of M. avium subsp. paratuberculosis genomic DNA, 5 to 10 fg of M. avium subsp. avium genomic DNA, and 2 to 5 fg of DNA from other mycobacterial species. Identification accuracy of the MAC multiplex was evaluated by testing 53 bacterial reference strains consisting of 28 different mycobacterial species and 12 nonmycobacterial species. Identification accuracy in a clinical setting was evaluated for 223 clinical MAC isolates independently identified by other methods. Isolate identification agreement between the MAC multiplex and these comparison assays was 100%. The novel MAC multiplex is a rapid, reliable, and simple assay for discrimination of MAC species and subspecies in liquid culture media.

Isolation of Mycobacterium avium complex from a Thoroughbred racehorse with fatal pneumonia

Isolation of Mycobacterium avium complex from a Thoroughbred racehorse with fatal pneumonia

Clinical Significance of Isolation of Mycobacterium avium Complex From Respiratory Specimens

Mycobacterium avium complex (MAC) is frequently considered to be a contaminant or transient colonizer. To the best of our knowledge, there have been very few reports regarding the clinical significance of MAC isolates in respiratory specimens, and the associated disease spectrum in Taiwan. The purpose of this study was to investigate the clinical significance of MAC isolates in respiratory specimens. We retrospectively reviewed the medical records of patients in a medical center in Southern Taiwan from whom MAC isolates were recovered from respiratory specimens, and analyzed their clinical features, chest imaging findings, treatment and prognosis. We also performed an antibiotic susceptibility test on our MAC isolates. The 64 isolates used in this study were recovered from April to October 2001 from respiratory specimens in 54 patients admitted to Kaohsiung Veterans General Hospital, Taiwan. According to the 2007 criteria of the American Thoracic Society, a total of 12 patients (22.2%) had clinically significant MAC pulmonary disease. Despite the increased frequency of recovering MAC from respiratory specimens, most cases did not meet the criteria of American Thoracic Society for clinically significant nontuberculous pulmonary disease. The minimum inhibitory concentrations of drugs against these MAC isolates might help to guide treatment, but further studies should be done.

Susceptibility test of the Mycobacterium avium complex to sixteen anti-infective agents

To compare the in vitro activities of 13 anti-infective agents and 3 new quinolones (sitafloxacin, gatifloxacin and moxifloxacin) against Mycobacterium avium complex (MAC) isolates, and therefore to explore the possibility of using these quinolones to treat MAC diseases. The minimal inhibitory concentration (MIC) of the above 16 anti-infective agents, including sitafloxacin, gatifloxacin and moxifloxacin against MAC isolates was determined by using agar dilution methods, and then the MIC90s of the different anti-infective agents were compared. The MICs of M. avium isolates showed a wider range and was less sensitive to most of the anti-infective agents as compared with M. intracellulare isolates. The MIC90s of clarithromycin against M. avium and M. intracellulare isolates were 32 mg/L and 16 mg/L, respectively, which were the lowest among 4 macrolide compounds. The MIC90 of rifalazil were 0.5 mg/L and 0.25 mg/L, respectively, which were the lowest among 4 rifamycin compounds. The MIC90 of sitafloxacin against M. avium and M. intracellulare isolates were both 4 mg/L, which were the lowest among 5 quinolones. For gatifloxacin and moxifloxacin, the MIC90 against M. avium and M. intracellulare isolates were both 8 mg/L. Two clarithromycin-sensitive strains (MIC=0.5 mg/L) showed a similar MIC of the lower limit for other compounds. Three clarithromycin-insensitive strains (MIC=64 mg/L) showed a similar MIC of the upper limit for other compounds except quinolones. Rifalazil, sitafloxacin, gatifloxacin and moxifloxacin showed acceptable in vitro activities against MAC isolates.

In Vitro Activity of a New Isothiazoloquinolone, ACH-702, against Mycobacterium tuberculosis and Other Mycobacteria

In this work, we describe the activity of ACH-702 against clinical isolates of Mycobacterium tuberculosis and six different nontuberculous mycobacteria. The MIC(50) and MIC(90) of both susceptible and drug-resistant M. tuberculosis strains tested were 0.0625 and 0.125 microg/ml, respectively. The MIC(50) and MIC(90) values for Mycobacterium fortuitum isolates were 0.0625 microg/ml in both cases; Mycobacterium avium complex isolates showed MIC(50) and MIC(90) values of 0.25 and 4 microg/ml, respectively.

Nontuberculous Mycobacteria in Solid Organ Transplant Recipients

Nontuberculous Mycobacteria in Solid Organ Transplant Recipients