The mycobacteriology of non-tuberculous mycobacteria

Extensor Tenosynovitis due to Mycobacterium marseillense Infection in a Renal Transplant Recipient

Renal transplant recipients are at an increased risk of atypical nontuberculous mycobacterial (NTM) infections. Infections caused by NTM are uncommon in the general population, rarely occurring in immunocompetent individuals. NTM infections are an uncommon cause of tenosynovitis. Mycobacterium marseillense is a rare, atypical mycobacteria that has been reported to cause pulmonary and cutaneous infections; however, no previous reports of this pathogen causing tenosynovitis exist. This case reports a 73-year-old male renal transplant recipient who presented with chronic extensor tenosynovitis of the right hand caused by M marseillense. The patient was treated with radical extensor tenosynovectomy and 6 months of antibiotic treatment. A review of literature on tenosynovitis caused by atypical mycobacteria was performed. The patient successfully responded to treatment with no complications or recurrence of infection at the 18-month follow-up. Tenosynovitis of the hand caused by atypical mycobacteria is rare. A high index of suspicion is required to prevent a delay in diagnosis, particularly in immunocompromised individuals.

Lymphadenitis by non-tuberculous mycobacteria in children

BACKGROUND

Non-tuberculous mycobacteria (NTM) constitute an important cause of cervical lymphadenitis in immunocompetent children. The aims of this study were to estimate the incidence of lymphadenitis due to NTM in children in Cyprus and to describe the characteristics, diagnostic approach, management and outcome of such infections.

METHODS

Children aged 1-5 years old, evaluated at Archbishop Makarios III Hospital, Nicosia, Cyprus, from 1 January 2007 to 31 December 2016 for lymphadenopathy, were included in the study. All children had positive lymph node culture for NTM.

RESULTS

A total of 22 cases of culture-positive lymphadenitis caused by NTM were reviewed. Patient age ranged from 16 to 55 months. Tuberculin skin test produced an induration in 81.0% of cases (diameter, 4-17 mm). Mycobacterium avium was isolated in 17 cases (77.3%), M. intracellulare in three (13.6%), M. paraffinicum in one (4.5%) and M. kansasii in one case (4.5%). All 22 patients underwent surgical excision of affected nodes. Additional anti-mycobacterial treatment was given when complete excision was not achieved or for post-surgical recurrence. Complications were few and included scar in three children and one case of transient facial nerve palsy.

CONCLUSION

Surgical excision of NTM-infected lymph nodes is an effective diagnostic and therapeutic approach. When total surgical excision is not feasible, a combination of partial excision with a clarithromycin-including drug regimen appears safe, effective and causes milder and fewer complications than surgery alone.

Mycobacterial Prevalence and Antibiotic Resistance Frequency Trends in Taiwan of Mycobacterial Clinical Isolates From 2002 to 2014

Tuberculosis, caused by Mycobacterium tuberculosis complex (MTBC) infections, is one of the most widespread infectious diseases worldwide. Nontuberculous mycobacteria (NTM) also cause chronic pulmonary infections, however, NTM infection is generally overlooked.This study analyzed the frequencies of MTBC and NTM clinical isolates from 181,132 specimens obtained from patients in Taiwan suspected of having a pulmonary mycobacterial infection from 2002 to 2014. The resistant rates to 4 first-line antibiotics (isoniazid, ethambutol, rifampicin, and streptomycin) of 9079 clinical MTBC isolates were also examined by the modified agar proportion method.Overall, the mycobacterial isolation rate was 8.65%, and this consisted of MTBC isolation rate of 5.01% and NTM isolation rate of 3.63%. The prevalence of MTBC isolates among the identified mycobacterial strains could be seen to decrease significantly from 82.5% in 2002 to 41.18% in 2014. Notably, the corresponding NTM prevalence increased 3.36 fold from 17.54% in 2002 to 58.82% in 2014. The frequencies of MTBC and NTM isolates showed a reciprocal trend with the crossing over occurring in the years 2010 and 2011. Although the resistance rates of the MTBC isolates to isoniazid and streptomycin were relatively stable over the study period, resistance rates of the MTBC isolates against rifampicin and ethambutol fluctuated across the study period. Overall, the incidence of multidrug resistance was relatively consistent at about 1.74%.The diagnosis, identification, and susceptibility tests for NTM should be standardized and integrated into appropriate clinical settings to cope with the increase in NTM infections. In addition, the documentation of the antibiotic resistance rates of MTBC clinical isolates to the antibiotic treatments most often clinically prescribed over a decade provides valuable clues and reference points for effective mycobacterial control.

Trends of mycobacterial clinical isolates in Taiwan

Non-tuberculous mycobacteria (NTM) can cause chronic pulmonary infection, however, NTM infection is generally overlooked. This retrospective study analyzed the frequencies of Mycobacterium tuberculosis complex (MTBC) and NTM clinical isolates from 99 200 specimens of patients suspected with pulmonary mycobacterial infection in Taiwan from 2002-2007. A total of 8024 mycobacterial isolates, including 5349 MTBC and 2675 NTM, were obtained from the 99 200 specimens in the study period. The overall mycobacterial isolation rate was 8.09% (8024/99 200), and the overall MTBC and NTM isolation rate was 5.39% (5349/99 200) and 2.7% (2675/99 200), respectively. Notably, the prevalence of NTM isolates among the identified mycobacteria strains was increased 2.6 fold from 2002 (17.54%, 147/838) to 2007 (45.80%, 659/1439). The frequencies of MTBC and NTM isolates showed a reciprocal trend: the NTM isolation rates were steadily increasing while the overall mycobacterial isolation rates remained stable over the study period. Our results suggest that the diagnosis, identification and susceptibility tests for NTM should be standardized and integrated in clinical routines, for providing the information of NTM infection and prescribing clinical treatment in a more precise and efficient way to reduce the increasing NTM in the studied area.

Antimycobacterial terpenoids from Juniperus communis L. (Cuppressaceae)

ETHNOPHARMACOLOGICAL RELEVANCE

Juniperus communis is a plant which has been reported as a traditional cure for tuberculosis (TB) and other respiratory diseases.

AIM OF THE STUDY

The aim of this study was to isolate and identify the constituents responsible for the activity of the n-hexane extract of Juniperus communis roots against Mycobacterium tuberculosis H(37)Rv and Juniperus communis aerial parts against Mycobacterium aurum. Subsequently, it was to evaluate the activity of the pure isolated compounds against (i) drug-resistant Mycobacterium tuberculosis variants, (ii) non-replicating Mycobacterium tuberculosis and (iii) a range of non-tuberculous mycobacteria (NTM).

MATERIALS AND METHODS

The antimycobacterial activity of Juniperus communis extracts, fractions and constituents was determined against Mycobacterium tuberculosis H(37)Rv, and against rifampicin-, isoniazid-, streptomycin- and moxifloxacin-resistant variants, using the microplate broth Alamar Blue assay (MABA) method. Isolated constituents were tested against non-replicating Mycobacterium tuberculosis H(37)Rv, using the low oxygen recovery assay (LORA), and against NTM (Mycobacterium aurum, Mycobacterium phlei, Mycobacterium fortuitum and Mycobacterium smegmatis), using a broth microdilution method. Cytotoxicity studies were performed using mammalian Vero cells.

RESULTS

The antimycobacterial activity of Juniperus communis was attributed to a sesquiterpene identified as longifolene (1) and two diterpenes, characterised as totarol (2) and trans-communic acid (3). All compounds were identified following analysis of their spectroscopic data (1D- and 2D-NMR, MS) and by comparison with the literature and commercial authentic standards when available. Revised assignments for 3 are reported. Totarol showed the best activity against Mycobacterium tuberculosis H(37)Rv (MIC of 73.7 microM). It was also most active against the isoniazid-, streptomycin-, and moxifloxacin-resistant variants (MIC of 38.4, 83.4 and 60 microM, respectively). Longifolene and totarol were most active against the rifampicin-resistant variant (MICs of 24 and 20.2 microM, respectively). Totarol showed the best activity in the LORA assay (MIC of 81.3 microM) and against all NTM species (MICs in the range of 7-14 microM). Trans-communic acid showed good activity against Mycobacterium aurum (MIC of 13.2 microM). The low selectivity indices (SI) obtained following cytotoxicity studies indicated that the isolated terpenoids were relatively toxic towards mammalian cells. This is the first report of the isolation of (1) and (2) from Juniperus communis roots, and of (3) from the aerial parts. The antimycobacterial activity of (1) and (3), and the activity of (2) against Mycobacterium aurum, Mycobacterium fortuitum and Mycobacterium phlei, is reported for the first time. The effect of totarol on drug-resistant variants and non-replicating Mycobacterium tuberculosis has never been published.

CONCLUSIONS

The presence of antimycobacterial terpenoids in Juniperus communis aerial parts and roots justifies, to some extent, the ethnomedicinal use of this species as a traditional anti-TB remedy.

Reliable identification of mycobacterial species by PCR-restriction enzyme analysis (PRA)-hsp65 in a reference laboratory and elaboration of a sequence-based extended algorithm of PRA-hsp65 patterns

BACKGROUND

Identification of nontuberculous mycobacteria (NTM) based on phenotypic tests is time-consuming, labor-intensive, expensive and often provides erroneous or inconclusive results. In the molecular method referred to as PRA-hsp65, a fragment of the hsp65 gene is amplified by PCR and then analyzed by restriction digest; this rapid approach offers the promise of accurate, cost-effective species identification. The aim of this study was to determine whether species identification of NTM using PRA-hsp65 is sufficiently reliable to serve as the routine methodology in a reference laboratory.

RESULTS

A total of 434 NTM isolates were obtained from 5019 cultures submitted to the Institute Adolpho Lutz, Sao Paulo Brazil, between January 2000 and January 2001. Species identification was performed for all isolates using conventional phenotypic methods and PRA-hsp65. For isolates for which these methods gave discordant results, definitive species identification was obtained by sequencing a 441 bp fragment of hsp65. Phenotypic evaluation and PRA-hsp65 were concordant for 321 (74%) isolates. These assignments were presumed to be correct. For the remaining 113 discordant isolates, definitive identification was based on sequencing a 441 bp fragment of hsp65. PRA-hsp65 identified 30 isolates with hsp65 alleles representing 13 previously unreported PRA-hsp65 patterns. Overall, species identification by PRA-hsp65 was significantly more accurate than by phenotype methods (392 (90.3%) vs. 338 (77.9%), respectively; p < .0001, Fisher's test). Among the 333 isolates representing the most common pathogenic species, PRA-hsp65 provided an incorrect result for only 1.2%.

CONCLUSION

PRA-hsp65 is a rapid and highly reliable method and deserves consideration by any clinical microbiology laboratory charged with performing species identification of NTM.

Causes of and clinical sequelae of delays in reporting species identification of mycobacteria other than Mycobacterium tuberculosis and Mycobacterium avium complex

We tracked cultures submitted to a laboratory in 2004 in which mycobacteria other than Mycobacterium tuberculosis or Mycobacterium avium complex were grown (n = 11). We reviewed clinical information, other mycobacterial cultures, and radiologic findings. We measured the time from specimen submission to first growth and to final species identification. We assessed the response to this information based on notes, laboratory tests, consultations, and radiology studies. The median time to identification was 68 days (47-292 days). In 5 cases, the clinician failed to retrieve the data, and in 3 of these cases, there was a resultant loss of opportunity to treat. In 3 cases, the laboratory never reported a definitive species, and in 3 cases, the culture results were clinically unimportant. We show that the results of positive cultures of these mycobacteria are effectively lost because they are not available in a timely fashion, and even when available, the results are overlooked.

Mycobacterium tuberculosis (Mtb) isocitrate dehydrogenases show strong B cell response and distinguish vaccinated controls from TB patients

Proteins released from Mycobacterium tuberculosis (Mtb) during late logarithmic growth phase are often considered candidate components of immunogenic or autolysis markers. One such protein is isocitrate dehydrogenase (ICD), a key regulatory enzyme in the citric acid cycle. We have evaluated the immunogenic properties of two isoforms of Mtb ICD and compared them with the control antigens heat-shock protein 60 and purified protein derivative (PPD). PPD lacks the sensitivity to distinguish between bacillus Calmette-Guérin (BCG)-vaccinated and tuberculosis (TB)-infected populations, and, therefore, epidemiological relevance of PPD in BCG-vaccinated regions is debatable. We show that Mtb ICDs elicit a strong B cell response in TB-infected populations and can differentiate between healthy BCG-vaccinated populations and those with TB. The study population (n = 215) was categorized into different groups, namely, patients with fresh infection (n = 42), relapsed TB cases (n = 32), patients with extrapulmonary TB (n = 35), clinically healthy donors (n = 44), nontuberculous mycobacteria patients (n = 30), and non-TB patients (culture negative for acid-fast bacteria but carrying other infections, n = 32). The Mtb ICDs showed statistically significant antigenic distinction between healthy BCG-vaccinated controls and TB patients (P < 0.0001) and those with other infections. Although extrapulmonary infections could not be discriminated from healthy controls by heat-shock protein 60 (P = 0.2177), interestingly, the Mtb ICDs could significantly (P < 0.0001) do so. Our results highlight the immunodominant, immunosensitive, and immunospecific nature of Mtb ICDs and point to an unusual property of this tricarboxylic acid energy cycle enzyme.