Use of green fluorescent protein labeled non-tuberculous mycobacteria to evaluate the activity quaternary ammonium compound disinfectants and antibiotics

Abstract Although infections with NonTuberculous Mycobacteria have become less common in AIDS patients, they are important opportunistic infections after surgical procedures, likely because they are ubiquitous and not efficiently killed by many commonly used disinfectants. In Venezuela there have recently been many non-tuberculous mycobacteria soft tissue infections after minor surgical procedures, some apparently related to the use of a commercial disinfectant based on a Quaternary Ammonium Compound. We studied the activity of this and other quaternary ammonium compounds on different non-tuberculous mycobacteria by transforming the mycobacteria with a dnaA-gfp fusion and then monitoring fluorescence to gauge the capacity of different quaternary ammonium compounds to inhibit bacterial growth. The minimum inhibitory concentration varied for the different quaternary ammonium compounds, but M. chelonae and M. abscessus were consistently more resistant than M. smegmatis, and M. terrae more resistant than M. bovis BCG.

Disease caused by non-tuberculous mycobacteria: diagnostic procedures and treatment evaluation in the North of Buenos Aires Province

Non-tuberculous mycobacteria (NTM) have emerged as pathogens frequently associated to HIV co-infection. The aims of this study were to describe the clinical importance of NTM in patients from the North of Buenos Aires Province and the drug-susceptibility patterns in relation with the therapy used. A total of 23,624 clinical specimens were investigated during the period 2004-2010. Ziehl-Neelsen stain and cultures were used for diagnosis. Molecular and biochemical tests were performed to identify the mycobacteria. TB and mycobacterioses cases were 2 118 and 108 respectively. Sixteen NTM species were found: Mycobacterium avium and Mycobacterium intracellulare as the main causative agents. Infections produced by more than one species at the same time were confirmed (4 cases). Macrolides and fluoroquinolones were the most active in vitro drugs. Treatment evaluation showed that 68.0 % of the cases completed the therapy, 20 % died; and 12 % were relapses. The cases in which the treatment outcome was evaluated received an individual tailor-made therapeutic scheme including those drugs showing in vitro activity and presumed in vivo usefulness. More than a quarter of the patients had HIV co-infection and the majority of the deaths were associated with this co-infection.

Enfermedad causada por micobacterias no tuberculosas: diagnóstico y evaluación del tratamiento en el norte del Gran Buenos Aires. Las micobacterias no tuberculosas (MNT) emergieron como patógenos frecuentemente asociados a la co-infección con el HIV. EL objetivo del estudio fue describir la importancia clínica de las MNT en pacientes de la región norte de la provincia de Buenos Aires y los patrones de drogo-sensibilidad en relación con la terapia empleada. Se investigó un total de 23.624 especímenes clínicos durante, el período 2004-2010. La tinción de Ziehl-Neelsen y los cultivos se utilizaron para diagnóstico. Las micobacterias fueron identificadas mediante pruebas bioquímicas y moleculares. Los casos de tuberculosis y micobacteriosis fueron 2 118 y 108, respectivamente. Se encontraron 16 especies de MNT, siendo las principales, Mycobacterium avium y Mycobacterium intracellulare. En 4 casos se confirmaron infecciones producidas por más de una especie al mismo tiempo. Los macrólidos y las fluoroquinolonas tuvieron mayor actividad in vitro. La evaluación del tratamiento confirmó que el 68 % de los casos completó la terapia; 20 % murió y el 12 % recayó. Los casos en los que se evaluó el tratamiento recibieron un esquema terapéutico individual incluyendo aquellas drogas que mostraron actividad in vitro. Más de un cuarto de los pacientes tuvieron co-infeccion con el HIV y la mayoría de las muertes estuvieron asociadas con esta co-infección.

Pulmonary disease due to mycobacterium massiliense.

We report a case of a patient suffering from multidrug-resistant pulmonary tuberculosis (MDR-PTB) who later developed an invasive infection of the respiratory tract with a rapidly growing non-tuberculous mycobacteria (NTM), recently identified as Mycobacterium massiliense, closely related to M. abscessus. To the best of our knowledge, this is the first case of M. massiliense infection being reported from India.

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 Mycobocterium 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

Laboratory aspects of clinically significant rapidly growing mycobacteria.

The pathogenic potential of the rapidly growing mycobacteria (RGM) has started being recognized. This is due to more sensitive and specific techniques in the laboratory. The RGM are generally defined as nontuberculous species of mycobacteria that show visible growth on agar media within 7 days. RGM are widely distributed in nature and have been isolated from natural water, tap water, and soil. Several biochemical tests, high performance liquid chromatography, and molecular techniques have been developed for rapid identification of these species. The American Thoracic Society and the Infectious Disease Society of America recommend that RGM should be identified to the species level using a recognized acceptable methodology such as polymerase chain reaction restriction enzyme analysis or biochemical testing and routine susceptibility testing of RGM should include amikacin, imipenem, doxycycline, the fluorinated quinolones, a sulphonamide or trimethoprim-sulphamethoxazole, cefoxitin, clarithromycin, linezolid, and tobramycin. The diseases caused by these organisms have varied manifestations. They have been responsible for a number of healthcare-associated outbreaks and pseudo-outbreaks. For recognition of outbreaks, it is important to be familiar with the causative organisms like RGM which are most frequently involved in healthcare-associated outbreaks and pseudo outbreaks. It is essential to intervene as soon as possible to interrupt this transmission. Large gaps still exist in our knowledge of RGM. Unquestionably more studies are required. Through this review, we wish to emphasize that reporting of RGM from clinical settings along with their sensitivity patterns is an absolute need of the hour.

Isolation- drug resistance profile and molecular characterization of indigenous typical and atypical mycobacteria

One hundred and fifty mycobacterial isolates from different pathological Labs, of Karachi were collected and screened as acid fast. On the bases of phenotypic and biochemical results, it was found that, 58.66% isolates were typical mycobacteria while 41.33% belonged to atypical mycobacteria. The individual percentages of different mycobacterial species include: M. xenopi 35%, M. thermoresistible 19%, M. terrae complex 6%, M. marinum 6%, M fortuitum 6%, M. kansasii 25% and M tuberculosis 58.66%. The sensitivity of mycobacterial isolates was determined against 5 first line, 3 second line and 1 third line anti-tuberculosis drugs. The highest number of the isolates [typical and atypical mycobacteria] offered resistance against isoniazid and streptomycin. Clarithromycin was found to be the drug of choice as regards the drug sensitivity in case of atypical mycobacterial isolates. A total of 40 isolates were subjected to PCR based identification and differentiation of 16S rRNA gene[s]. Accordingly, 37.5% isolates were identified as typical mycobacteria while 25% were identified as atypical mycobacteria. These findings carry significance because a detailed research based identification [PCR and Multiplex PCR based] regarding indigenous mycobacteria has been reported for the first time in Pakistan. However, both the approaches [conventional and molecular methods] have experimental importance while identifying these organisms

Sequential Bilateral Lung Resection in a Patient with Mycobacterium Abscessus Lung Disease Refractory to Medical Treatment

Mycobacterium abscessus (M. abscessus) is the second most common nontuberculous mycobacteria (NTM) in South Korea. Nevertheless, the diagnosis and treatment of M. abscessus lung disease can be problematic. Surgical resection has been tried for patients with localized M. abscessus lung disease refractory to medical treatment. Here, we report on a 25-year-old woman with M. abscessus lung disease who had been diagnosed and treated three times for pulmonary tuberculosis. She was initially diagnosed as having M. intracellulare lung disease; however, M. abscessus was isolated after several months of medication. She had multiple bronchiectatic and cavitary lesions bilaterally, and M. abscessus was repeatedly isolated from her sputa despite prolonged treatment with clarithromycin, ethambutol, moxifloxacin, and amikacin. She improved only after sequential bilateral lung resection. Based on the experience with this patient, we suggest that, if medical treatment fails, surgical resection of a diseased lung should be considered even in patients with bilateral lesions.

Clonal Dissemination of Extended-Spectrum beta-Lactamase (ESBL)-Producing Klebsiella pneumoniae Isolates in a Korean Hospital

In this study, we investigated the molecular characteristics of extended-spectrum beta-lactamase (ESBL)-producing Klebsiella pneumoniae isolates that were recovered from an outbreak in a Korean hospital. A new multilocus sequence typing (MLST) scheme for K. pneumoniae based on five housekeeping genes was developed and was evaluated for 43 ESBL-producing isolates from an outbreak as well as 38 surveillance isolates from Korea and also a reference strain. Overall, a total of 37 sequence types (STs) and six clonal complexes (CCs) were identified among the 82 K. pneumoniae isolates. The result of MLST analysis was concordant with that of pulsedfield gel electrophoresis. Most of the outbreak isolates belonged to a certain clone (ST2), and they produced SHV-1 and CTX-M14 enzymes, which was a different feature from that of the K. pneumoniae isolates from other Korean hospitals (ST20 and SHV-12). We also found a different distribution of CCs between ESBL-producing and -nonproducing K. pneumoniae isolates. The MLST method we developed in this study could provide unambiguous and well-resolved data for the epidemiologic study of K. pneumoniae. The outbreak isolates showed different molecular characteristics from the other K. pneumoniae isolates from other Korean hospitals.

Estimation of efflux mediated multi-drug resistance and its correlation with expression levels of two major efflux pumps in mycobacteria.

Multidrug resistance has been posing an increasing problem in the treatment of tuberculosis. Mutations in the genomic targets of drugs have been identified as the major mechanism behind this resistance. However, high degree of resistance in some isolates towards major drugs like rifampicin, isoniazid, ethambutol and streptomycin can not be explained solely on the basis of mutations. Besides this, certain other mechanisms like efflux pumps have also been considered as alternative mechanisms in the drug resistant isolates where there is no mutation and these mechanisms are specially important for drug resistance in non-tuberculous mycobacteria (NTM). In this study, we have estimated efflux pump mediated drug resistance in different mycobacterial species with the help of efflux pump inhibitors. All major anti-tuberculous drugs have been shown to be extruded by efflux pumps and the degree to which these drugs are extruded, vary in different mycobacterial species and isolates. The correlation of this resistance with functional activity of two major efflux pump genes pstB and Rv1258c was also assessed by reverse transcription PCR. Besides the significant role of these pumps observed, other efflux pumps, present in mycobacteria, may also be involved in drug resistance and need to be investigated.

Non tuberculous mycobacteria isolated from clinical specimens at a tertiary care hospital in South India.

PURPOSE: This is a retrospective analysis of the isolation rates of nontuberculous mycobacteria (NTM) from various clinical specimens and their antimicrobial susceptibility patterns. METHODS: All NTM isolated between 1999 and 2004 at Christian Medical College, Vellore, South India, were identified with various biochemical tests. Antimicrobial susceptibility test for all NTM was performed by standard methods. RESULTS: A total of 32,084 specimens were received for culture, of which 4473 (13.9%) grew acid fast bacilli (AFB). Four thousand three hundred (96.1%) of the AFB were M. tuberculosis while 173 (3.9%) were NTM. Of the 173 NTM, 115 (66.5%) were identified to the species level. Pus, biopsy specimens and sputum specimens yielded most of the NTM of which M. chelonae (46%) and M. fortuitum (41%) accounted for majority of them. M. chelonae and M. fortuitum, showed highest susceptibility to amikacin (99.2%). NTM were repeatedly isolated from seven sputum specimens, 15 biopsy and pus specimens, two CSF and two blood cultures. Six were isolated from patients with AIDS and five from post transplant patients. CONCLUSIONS: The isolation of NTM from various clinical specimens is reported in this study to highlight the associated diseases and therapeutic options in these infections.

Nontuberculous mycobacteria in soils of La Pampa province (Argentina)

The presence of nontuberculous mycobacteria (NTM) was investigated in forty soil samples belonging to the four physiographic regions (Eastern, Central, Southern and Western) that constitute La Pampa province. The presence of NTM in 67.5 of these soil samples was determined. The density of mycobacteria ranged 25-4,500 mycobacteria g-1 dry soil (mean = 516 CFU g-1). Significant differences were found in relation to both the investigated regions (p < 0.01) and the soil pH (r = 0.44*) (P = 0.02). The mycobacteria represented less than 0.00001 of the total aerobic bacteria found in the soils. Twenty-seven isolated mycobacteria were classified according to the culture, biochemical, enzymatic characteristics and antibiotic sensitivity. Mycobacterium fortitium was the dominant mycobacterium and was detected in 63 of the positive soils. This species showed ability for living in sandy to sandy loam soils, within a wide pH range (6.5-9.7) and organic matter (4.15-83.63 g kg-1). Two other species were M. phlei (range = 50-4,500 CFU g-1) and M. kansasii (range = 50-500 CFU g-1).

Vancomycin for controlling contamination of selective Kirchner's liquid medium in the culture of gastric lavage for tubercle bacilli.

Gastric lavage (GL) was collected for culture of tubercle bacilli from children too young to expectorate sputum. The selective Kirchner's liquid medium (SKLM), routinely used as one of the media for culture of all extrapulmonary specimens, was found to often get contaminated when cultured with GL. We have shown that vancomycin at a concentration of 10 mg/l successfully reduced the contamination from about 60 to 20 per cent, and enhanced the isolation rate of tubercle bacilli from 3 to 6 per cent. Decontamination of the liquid culture before subculture on solid medium also helped to reduce the contamination rate. Vancomycin was found to be an effective selective drug for use in the Kirchner's liquid medium for culture of tubercle bacilli.

Infecção por Mycobacterium szulgai em hemofílico com SIDA / Mycobacterium szulgai infection in a patient with hemophilia and AIDS

Mycobacterium szulgai is a scotochromogenic species recently recognized as a human pathogen. Twenty-nine cases of disease caused by M. szulgai in humans have been reported. Pulmonary disease indistinguishable from that caused by M. tuberculosis was the commonest type of infection caused by M. szulgai. Olecranon bursitis was reported in 3 cases and disseminated infection was noted in 3 cases occurring in immunocompromised patients without AIDS. The authors report the first case of pulmonary disease caused by M. szulgai in Brazil and the first case in patient with AIDS in the world literature.

Correlation between inhibitory effect of quinolones and mycolic acid metabolism in mycobacteria.

Mycolic acids are important components having a significant role in maintaining the rigidity of mycobacterial cell wall. They could also be the barrier for penetration of certain drugs into the bacterial cell. A novel in vitro model system was established for assessing the effect of Ciproflaxacin on mycolic acid metabolism in pathogenic mycobacteria M. Kansasii (which has similar mycolic acid pattern to that from M. leprae) and the effect of norfloxacin in M. intracellulare. These test mycobacteria were exposed in their midlogarithmic phase of growth to 0.5, 1, 2, 3, 4, 5 and 6 micrograms ml of ciprofloxacin and norfloxacin respectively for 1, 2 and 24 hours. Ciprofloxacin completely inhibited the synthesis of mycolates in M. kansasii at 3, 4 and 5 micrograms/ml; whereas norfloxacin exhibited its maximum inhibitory action on mycolic acids in M. intracellulare at 6 micrograms/ml for all the durations of exposure. Inhibition of mycolates directly correlated with bacterial viability which was estimated by colony forming units. The effect of quinolones on mycolic acid metabolism appears to be direct and not secondary to DNA gyrase. The results obtained from this study and our previous findings show that mycolic acid metabolism is affected by various groups of drugs, whose primary sites of activity may be different. The findings of the present study may have significant therapeutic implications in leprosy and other mycobacterial diseases.

In vitro drug susceptibility of Mycobacterium other than tubercle bacilli.

MOTT were isolated from clinical specimens from the Division of Mycobacteriology, Department of Microbiology, Siriraj Hospital, Mahidol University, and also from natural sources, namely water and soil in the Bangkok area from January to December, 1987. The strains isolated were as follows: 30 M. fortuitum fortuitum, 5 M. fortuitum peregrinum 3 M. fortuitum 3 rd. biovariant complex, 3 M. chelonae chelonae, 7 M. chelonae abscessus. Of these, 5 strains were isolated from clinical specimens and the other 43 were from the environment. The pattern of drug susceptibility to antituberculous and antimicrobial agents revealed that they were resistant to antituberculous agents but susceptible to aminoglycosides (which contain a central ring of 2-deoxystreptamine) such as amikacin (83% of cultures), netilmicin (83%), gentamicin (77%) and kanamycin (75%). Some strains were sensitive to tetracyclines (35%), but all were resistant to penicillins and cephalosporins.

Chest infection due to M. fortuitum in a case of lepromatous leprosy--a case report.

Lepromatous leprosy cases may be immunocompromised due to the extensive disease and also because of steroid therapy for repeated reactions. Such patients are likely to be at higher risk for getting opportunistic infection due to various environmental microbes. This paper reports a case of lepromatous leprosy with repeated lepra reaction who was found to have chest infection due to M. fortuitum. It is suggested that mycobacterial culture and sensitivity should be recommended in cases who are immunocompromised and whose pathological specimens contain acid fast bacilli. Species identification and sensitivity can be very helpful in proper management of such cases who will otherwise pass off as tuberculosis.

Studies on the Mycobacteria Isolated from Soil

Acid-fast microorganisms were isolated from 240 soil samples collected at two areas, Hiroshima, Japan and Seoul, Korea. The biological and biochemical characteristics of the isolated mycobacteria were tested and compared with those of 36 reference mycobacteria Strains. The isolation rate and distribution of these mycobacterial species from soil were compared using three kinds of media with emphasis on the two methods of isolation between the different geographical areas. One Strain from each of the 10 species among atypical mycobacteria isolated from soil in both areas was inoculated into ddY mice and the pathogenicity compared with that of Mycobacterium tuberculosis H37Rv up to 6 weeks. Susceptibility of the reisolated acid-fast bacilli to antimycobacterial agents was tested in vitro. Antibody responses against various mycobacterial antigens were tested using lepromatous type and tuberculoid type patient sera by the agar gel immunodiffusion. 1) No significant differences in the distribution of acid-fast bacilli were observed between soil samples from the two regions. 2) Rapid growers were by far the most frequent acid-fast bacilli isolated while no photochromogens were isolated from these soil samples. In addition, a minimal number of fastidious mycobacteria were isolated but not cultivable in subcultures. 3) Some of these soil acid-fast bacilli were capable of inducing only transient bacteriological and pathologic changes in mouse organs. 4) Acid-fast bacilli reisolated from organs of these infected mice were, in general, found to be resistant to antimycobacterial agents. 5) M. scrofulaceum antigen showed a precipitation reaction in agar gel immunodiffusion with the highest number of sera from leprosy patients.