ABSTRACT
A 38-year-old female with systemic lupus erythematosus (SLE) initiated belimumab treatment. One month later, she presented with a reddish painful swelling on her right lower leg.She was treated with ceftriaxone and vancomycin. However, novel erythematous papules and indurated nodules appeared on both her lower legs. Skin biopsy revealed microabscess formation with mixed cell granuloma surrounded by inflammatory cell infiltration within the dermis with subcutaneous fat tissue. A large number of acid-fast bacilli were observed with Ziehl–Neelsen staining. DNA sequencing of both the hsp65 and the 16S rRNA sequences showed a 100% match with the corresponding region of Mycobacterium haemophilum. Mycobacterial culture revealed satellite growth enhancement on Middlebrook 7H11 agar plates around a paper strip containing hemin. She was treated with levofloxacin, rifabutin, and ethambutol. Within 13 months, her cutaneous lesions improved markedly without any side effects. The B cell-targeted biologic belimumab, a fully humanized IgG1γ monoclonal antibody that inactivates B lymphocyte stimulator, has been considered to be beneficial for active SLE. However, this therapy could increase the risk for the development of biologic therapy-associated mycobacterial infections, both tuberculosis and nontuberculous mycobacteria infections.
ABSTRACT
A concentration of specimen is recommended for the effective recovery of Mycobacterium tuberculosis [MTB], but the bacteriological efficiency is not well evaluated. The present study evaluated the factors contributing to concentration efficiency of centrifugation and bead-based technique [TB-Beads; Microsens, UK] to recover MTB by using simple in vitro specimens. Four specimens were prepared [6.5 × 103; 8.1 × 104; 7.9 × 105; and 6.4 × 106 cfu/mL] of different concentrations with or without 5 × 104 of THP-1 cells [RIKEN BRC, Japan]. Specimens were subjected to centrifugation at 2000, 3000, and 4000g for 15 min, and to TB-Beads. The concentration and recovery rate were calculated to evaluate the efficiency of each method. The specimens containing a higher number of bacteria and THP-1 cells had a tendency to yield a higher concentration and recovery rate [p = 0.001-0.083]. MTB was recovered more efficiently with THP-1 cells from the 6.5 × 103 cfu/mL specimen by centrifugation [p= 0.001] than without them; 24.7-54.4% of MTB were recovered with THP-1 cells by centrifugation at 3000g for 15 min, while the recovery using TB-Beads was a maximum of 12.7%. The efficiency of centrifugation depends on the bacterial density and the co-existence of THP-1 cells. The efficiency of TB-Beads was not as high as centrifugation
ABSTRACT
We performed drug susceptibility testing on first- and second-line drugs in <i>Mycobacterium tuberculosis</i> (<i>M. tuberculosis</i>) for the first time in Ghana to obtain preliminary data on drug-resistant tuberculosis. Of 21 isolates (4 new cases and 17 treated cases), 5 (23.8%) were multi-drug resistant tuberculosis (MDR-TB) and 19 (90.5%) were resistant to at least one drug, but no extensively drug-resistant TB (XDR-TB) was identified. Since the target patients were Category II, IV or smear positive at follow-up microscopy, it is understandable that there were many drug-resistant TB cases. Six isolates were resistant to one or two second-line drugs, but the second-line drugs were not approved in Ghana. It is considered that the bacilli were imported from abroad. Preventing the import of drug-resistant TB bacilli is probably one of best ways to control TB in Ghana.
ABSTRACT
Conventional biochemical tests are the standard for the identification of Mycobacterium species, but molecular identifications are becoming more prevalent. The rpoB gene encodes the beta -subunit of RNA polymerase and is utilized for the identification of Mycobacterium species. In the present study, a stepwise Mycobacterium species identification algorithm using the 16S rRNA encoding gene and rpoB analysis was evaluated for its effectiveness. A total of 172 clinical Mycobacterium isolates were tested, and concordant results were obtained with 108 strains by using the conventional method and molecular methods [AccuProbe or DDH method]. In these 108 strains, 4 strains were identified by 16S rRNA gene analysis, but rpoB indicated no identical Mycobacterium species with more than 99% similarity. The remaining 64 strains were not identified by conventional method and commercial kits. Forty-two showed concordant results with 16S rRNA and rpoB analysis, and 13 strains were identified by 16S rRNA gene analysis although rpoB indicated no identical Mycobacterium species. On the other hand, 4 strains included 2 strains of Gordona and 2 strains of M. celatum type II which were identified by rpoB but not by 16S rRNA gene analysis. Finally, 5 strains could not be identified by analysis of either gene. The rpoB analysis can differentiate M. kansasii from M. gastri;M. malmoense from M. szulgai; M. abscessus from M. chelonae; M. peregrinum from M. septicum; M. porcinum from M. fortuitum; and M. farucinogense from M. senegalense-pairs that are not differentiated by 16S rRNA analysis. Additionally, Nocardia asteroids, Rhodococcus equi, Gordona aichiense, G. aurantiaca, G. bronchialis and G. terraeare able to be analyzed by using rpoB. The 16S rRNA gene identification is a rapid and prevalent method but still has some limitations. Therefore, the stepwise combination of rpoB with 16S rRNA gene analysis is an effective system for the identification of Mycobacterium species
Subject(s)
Humans , Algorithms , RNA, Ribosomal, 16S/genetics , Cytogenetic AnalysisABSTRACT
<I>M. tuberculosis</I> strains were isolated from clinically and bacteriologically confirmed patients to evaluate the susceptibility of clinical <I>M. tuberculosis</I> isolates to fluoroquinolone and to obtain molecular epidemiological information in Zambia,. The pathogens were subjected to susceptibility testing with isoniazid, rifampicin, ethambutol and streptomycin. The minimum inhibitory concentrations to ciprofloxacin, sparfloxacin and levofloxacin were also evaluated. The <I>gyrA</I>, fluoroquinolone resistance-determining region (QRDR), was sequenced and analysed. As a result, three of the 16 strains examined were resistant to isoniazid, rifampicin and⁄or streptomycin. All of the strains were susceptible to ciprofloxacin, levofloxacin and sparfloxacin. However, a unique <I>gyrA</I> gene variation of<I> M. tuberculosis</I> was identified in the isolates. One strain had a mutation (T73A) in QRDR. Additionally, 81.25% (13⁄16) of the strains tested had Thr at codon 88. Several variations of <I>gyrA</I> gene have been reported in relation to drug resistance. The <I>gyrA</I> variation data will be useful as epidemiological information. It may be important to monitor fluoroquinolone susceptibility even in developing countries for use against resistant <I>M. tuberculosis</I> infection, even though no fluoroquinolone resistance was observed in this study.
ABSTRACT
Two egg-based culture media were evaluated for detection of mycobacteria with Löwenstein-Jensen (L-J) as a gold standard. The conventional culture method was modified to improve laboratory diagnosis of tuberculosis in resource scarce countries by employing an inexpensive but sensitive and specific culture method. Sputum samples were collected from pulmonary tuberculosis suspects who visited the chest clinic at the University Teaching Hospital in Zambia. These samples were processed using three different sample treating procedures (with or without sample concentration) and cultured on L-J and Ogawa media for mycobacteria isolation. A total of 276 sputum samples were collected from 138 pulmonary tuberculosis suspects. When the L-J result was used as a standard, the sensitivity of Ogawa and modified Ogawa was 81.7% and 90.3% respectively. Similarly, the specificities of those methods were 96.7% and 92.3% respectively. In total, 90 samples (32.6%) were smear positive and 108 (39.1%) were culture positive. The positivity of each culture method was as follows: 93 (33.7%) in L-J, 98 (35.5%) in modified Ogawa, and 82 (29.7%) in original Ogawa. The contamination rate was 1.1%, 5.1%, and 9.8% for L-J, Ogawa and modified Ogawa respectively. The Ogawa culturing method is economical, simple and quick. Its low sensitivity was overcome by employing the concentration method, the sensitivity significantly improving from 81.7% to 90.3%. Ogawa techniques are ideal in overburdened TB laboratories with poor resources in developing countries.