Bedaquiline: 10 years later, the drug susceptibility testing protocol is still pending

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Comparative in-vitro activity of fleroxacin and other 6-fluoroquinolones against mycobacteria

The susceptibility of 11 clinical isolates of Mycobacterium tuberculosis, 3 M. kansasii,3 M. xenopi, 2 M.scrofulaceum, 2 M. marinum, 2 M. malmoense to fleroxacin,ciprofloxacin, norfloxacin, rifampicin, isoniazid, ethambutol, and streptomycin was determined by the standard proportion method (Middlebrook 7HlO agar). All M.tuberculosis,M. kansasii, M. xenopi,M. scrofulaceum, M. marinum,and M. malmoense isolates including those resistant to conventional antimycobacterials were inhibited by 0·5 mg/l of fleroxacin and ciprofloxacin, the lowest tested concentration. Fleroxacin and ciprofloxacin along with ofloxacin,pefloxacin, ansamycin, clofazimine and cycloserine were also tested against 14 isolates of the M. avium complex. Nine of 14 strains (64%) of the M. avium complex were found susceptible to 4 mg/l of fleroxacin and a similar percentage to the other quinolones. On the basis of its in-vitro potency and its favourable pharmacokinetic properties fleroxacin appears to be sufficiently active to warrantfurther experimental trials against difficult to treat mycobacteri

Pyrazinamide and Pyrazinoic Acid Activity against Tubercle Bacilli in Cultured Human Macrophages and in the BACTEC System

Pyrazinamide (PZA) has becomean essential component of current 6-month regimens for therapy of tuberculosis. Susceptible strains of tubercle bacilliconvert PZA to pyrazinoic acid (POA)through pyrazinamidase (PZase), which resistant strains and Mycobacterium bovis bacilleCalmette-Guerin lack. PZA susceptibility results obtained in cultured human macrophages were compared with those in the broth BACTEC system with 7H12 medium at pH 6.0 for strains known to bePZasepositive or -negative. Although added PDA was unable to inhibit tubercle bacilli in cultured macrophages, it was able to inhibit them at very high concentrations in the BACTEC broth. Intracellularly formed PDA would not be able to escape from the macrophage, and therefore would accumulate sufficiently to lower pH to toxic levels for tubercle bacilli. The results suggest that the cultured macrophages contribute actively or passively to the effectiveness of PZA, such as through the proposed mechanism of low pH generated by PZase in the phagolysosome

Extrapulmonary and Disseminated Infections Due to Mycobacterium malmoense: Case Report and Review

Mycobacterium malmoense is a potentially pathogenic species that was first described in 1977. During the past decade M. malmoense has been recognized with increasing frequency as a pulmonary pathogen. More than 180 cases of M. malmoense infection have been reported. Most of these infections affected a previously damaged lung. Other infection sites included the skin, lymph nodes, and bursae. Five cases of disseminated infection have been reported. The antituberculous drugs associated with the most favorable susceptibility patterns are rifampin and ethambutol. Because of the slow growth of M. malmoense on conventional, egg-based bacteriologic media, the incubation time should be >6 weeks; special solid and liquid media are recommended. We report a case of disseminated pulmonary and gastrointestinal infection due to M. malmoense in a patient with AIDS, who was treated successfully with a combination of rifabutin (ansamycin), clofazimine, and isoniazid. In addition, we review the characteristics of extrapulmonary and disseminated infections due to M. malmoens

Epidemiology and Clinical Significance of Nontuberculous Mycobacteria in Patients Negative for Human Immunodeficiency Virus in Switzerland

Over the last decades, the rate of isolation of tubercle bacilli has declined in the developed countries, while the incidence of infection with nontuberculous mycobacteria (NTM) has increased. In a retrospective study, we analyzed all cases of patients negative for human immunodeficiency virus (HIV) and from whom NTM were isolated in the Zurich area of Switzerland from 1983 to 1988. During the 6-year study period, 513 patients infected with NTM were identified, 34 of whom had clinically significant disease. The presentation of mycobacteriosis was found to be lung disease in 23 cases, soft-tissue disease in 10 cases, and disseminated disease in one case. The highest attack rate of pulmonary mycobacteriosis was 0.49% and was found in the group of patients 41-50 years old. During the 6-year period, the incidence of tuberculosis declined from 16.2 to 13.2 per 100,000 population, while the incidence of mycobacteriosis increased from 0.4 to 0.9 per 100,000 population. Clinically nonsignificant NTM isolates were found more frequently in patients with chronic lung diseases (P < .01) and especially in patients with a history of tuberculosis (P < .001

Evaluation of a Novel MALDI Biotyper Algorithm to Distinguish Mycobacterium intracellulare From Mycobacterium chimaera

Accurate and timely mycobacterial species identification is imperative for successful diagnosis, treatment, and management of disease caused by nontuberculous mycobacteria (NTM). The current most widely utilized method for NTM species identification is Sanger sequencing of one or more genomic loci, followed by BLAST sequence analysis. MALDI-TOF MS offers a less expensive and increasingly accurate alternative to sequencing, but the commercially available assays used in clinical mycobacteriology cannot differentiate between Mycobacterium intracellulare and Mycobacterium chimaera, two closely related potentially pathogenic species of NTM that are members of the Mycobacterium avium complex (MAC). Because this differentiation of MAC species is challenging in a diagnostic setting, Bruker has developed an improved spectral interpretation algorithm to differentiate M. chimaera and M. intracellulare based on differential spectral peak signatures. Here, we utilize a set of 185 MAC isolates that have been characterized using rpoB locus sequencing followed by whole genome sequencing in some cases, to test the accuracy of the Bruker subtyper software to identify M. chimaera (n = 49) and M. intracellulare (n = 55). 100% of the M. intracellulare and 82% of the M. chimaera isolates were accurately identified using the MALDI Biotyper algorithm. This subtyper module is available with the MALDI Biotyper Compass software and offers a promising mechanism for rapid and inexpensive species determination for M. chimaera and M. intracellulare

Laboratory Diagnosis of Mycobacterial Infections: New Tools and Lessons Learned

Even in the 21st century, tuberculosis continues to be a problem. Although the number of cases continues gradually to decrease in the United States, cases get more difficult to treat, specifically those that are multiple-drug resistant. Infection of one-third of the world's population ensures that tuberculosis will not disappear in the near future. In light of this, it will be useful to know the goals for the health care system and how these goals may be accomplished. Laboratory testing in the mycobacteriology field is experiencing more changes today than ever before. Determining what assays will be most useful to the clinician is a challenge, and acceptance of the new technology by the medical community an even greater one. Clinicians must use the best available resources to determine the most appropriate care for their patients and work together with the laboratory to ensure that the communication channels are open. This review focuses on current state-of-the-art resources useful for accurate and rapid laboratory diagnosis of mycobacterial infection

Practice guidelines for clinical microbiology laboratories: Mycobacteria

Mycobacteria are the causative organisms for diseases such as tuberculosis (TB), leprosy, Buruli ulcer, and pulmonary nontuberculous mycobacterial disease, to name the most important ones. In 2015, globally, almost 10 million people developed TB, and almost half a million patients suffered from its multidrug-resistant form. In 2016, a total of 9,287 new TB cases were reported in the United States. In 2015, there were 174,608 new case of leprosy worldwide. India, Brazil, and Indonesia reported the most leprosy cases. In 2015, the World Health Organization reported 2,037 new cases of Buruli ulcer, with most cases being reported in Africa. Pulmonary nontuberculous mycobacterial disease is an emerging public health challenge. The U.S. National Institutes of Health reported an increase from 20 to 47 cases/100,000 persons (or 8.2% per year) of pulmonary nontuberculous mycobacterial disease among adults aged 65 years or older throughout the United States, with 181,037 national annual cases estimated in 2014. This review describes contemporary methods for the laboratory diagnosis of mycobacterial diseases. Furthermore, the review considers the ever-changing health care delivery system and stresses the laboratory’s need to adjust and embrace molecular technologies to provide shorter turnaround times and a higher quality of care for the patients who we serve

Universal Genotyping in Tuberculosis Control Program, New York City, 2001–2003

Real-time universal genotyping decreased unnecessary treatment