[Evaluation of GeneXpert MTB/RIF and BACTEC-MGIT 960 for the detection of tuberculosis among pneumoconiosis-associated tuberculosis patients].

Objective: To evaluate the performence of GeneXpert MTB/RIF and BACTEC-MGIT 960 on detecting Mycobacterium tuberculosis and rifampicin resistance for pneumoconiosis-associated tuberculosis patients. Methods: The recruited 133 suspected active pneumoconiosis-associated tuberculosis hospitalized cases, morning sputum samples were collected to do modified L-J culture, conventional proportion method drug susceptibility test, GeneXpert MTB/RIF and BACTEC-MGIT 960. Analyze the sensitivity and specificity of the 133 sputum from patients, the positive rates of patients with tuberculosis in GeneXpert MTB/RIF test, BACTEC-MGIT 960 and modified L-J culture were 37.59%, 34.59% and 30.08% respectively. There was no significant difference among the three tests respectively (P>0.05) . According to the modified L-J culture, the sensitivity of GeneXpert MTB/RIF and BACTEC-MGIT 960 in detecting tuberculosis were 92.5% and 95.0% respectively, and specificity in rifampicin resistance were 86.0% and 91.4% respectively. There was no significant difference between GeneXpert MTB/RIF and BACTEC-MGIT 960 (P>0.05) . According to conventional proportion method drug susceptibility test, the sensitivity of GeneXpert MTB/RIF and BACTEC-MGIT 960 in detecting rifampicin resistance were 90.0% and 100%, and specificity were 92.6% and 96.4%. There was no significant difference between GeneXpert MTB/RIF and BACTEC-MGIT 960 (P>0.05) . Conclusion: The GeneXpert MTB/RIF has good performence of detecting tuberculosis and rifampicin resistance. It has good application value among pneumoconiosis-associated tuberculosis patients.

[The analysis of pathogens distribution and drug resistance of bacteria in sputum samples of pneumoconiosis patients combined with lower respiratory tract infection.]

Objective: To guide the rational use of antibiotic drugs in clinical practice for doctors by the analysis of pathogens distribution, transition and drug resistance of bacteria in sputum samples of pneumoconiosis patients combined with lower respiratory tract infection. Methods: 2 199 qualified sputum samples from 214 pneumoconiosis patients collected from January 2008 to December 2012 were examined by bacterium or fungus education. BioMerieux API and Eastern Cowin application software were used to do bacterial identification, and K-B method recommended by the NCCLS was used to take drug sensitivity tests. Results: 508 pathogens were isolated from sputum specimens and the positive rate among them was 23.1%. The majority of pathogens were fungus and Gram-negative bacteria, with the detection rates 50.0%, 40.7% respectively. Bacterial identification results show that the majority of pathogens of sputum samples were candida albicans, pseudomonas aeruginosa and acinetobacter baumannii. Susceptibility results show that P. aeruginosa was 100% sensitive to ceftriaxone (non-meningitis) and acinetobacter baumannii was 100% sensitivite to ampicillin/sulbactam, cefoperazone/sul-bactam and imipenem. These two bacteria were resistant to many kinds of antibiotic drugs, and the sensitive rates to cephalothin and clindamycin were 0%. Conclusion: The infections of pneumoconiosis patients combined with lower respiratory tract infection were fungi, pseudomonas aeruginosa and acinetobacter baumannii, which have a significant drug resistance. Doctors should consider the results of laboratory detection of pathogens and sensitivity test to select the antibiotic drugs in order to reduce the generation of resistant strains.

[Sequence analysis on drug-resistant gene of rpoB in MDR-TB among pneumoconiosis patients complicated with tuberculosis in Huainan mining district].

OBJECTIVE: To study the characteristics of drug-resistant genetic mutation of rpoB in multiple drugs resistant bacillus tuberculosis (MDR-TB) among patients of pneumoconiosis complicated with pulmonary tuberculosis. METHODS: A total of 114 clinical isolated strains of Mycobacterium tuberculosis were collected, MDR-TB were identified by conventional antimicrobial susceptibility test (AST). Their genomes DNA were extracted, the target genes were amplified by PCR, and the hot regions in the rpoB gene were analyzed by automated DNA sequenator. RESULTS: The results by AST showed that there were 31 strains of MDR-TB in the 114 clinical isolated strains, the rate of drug resistance was 27.19% (31/114). No mutation of rpoB was identified in 10 rifampicin-sensitive strains that randomly chosen, while conformation changes were found in MDR-TB strains, and the mutation rate of rpoB was 93.55% (29/31) in resistant strains, mainly concentrated in codon 531 (45.16%, 14/31) and 526 (29.03%, 9/31), happened base substitutions, including 27 unit point mutation and 2 two point mutation. CONCLUSIONS: The substitution of highly conserved amino acids encoded by rpoB gene results in the molecular mechanism responsible for RFP resistance in MDR-TB among patients of pneumoconiosis complicated with pulmonary tuberculosis. It also proves that rpoB gene is diversiform.

[Microbiologically identified isolates of Mycobacterium heckeshornense in two patients].

PURPOSE: To identify mycobacteria isolated from sputa of a 51-year-old female and a 72-year-old male patient with pneumoconiosis. OBJECT AND METHOD: Mycobacteria species were isolated from sputa of a 51-year-old female. The culture was always negative in spite of positive smears before the final isolation in 1988. A 72-year-old male patient suffered from pneumoconiosis and the acid-fast bacillus was isolated by routine sputum examination in 2003. These two strains of acid-fast bacilli were identified as Mycobacterium heckeshornense by partial sequencing of 16S rRNA and rpoB and conventional methods (biochemical and routine culture methods). RESULT: These two strains grew on 1% Ogawa's slant medium at 37 degrees C and 42 degrees C, but not at 28 degrees C. They formed yellowish colonies in the dark (Scotochromogen). They were classified as a slowly growing Mycobacteria. As it was difficult to distinguish M. heckeshornense from M. xenopi by conventional methods including growth rate, temperature range of mycobacterial growth, light coloration reaction, biochemical and biological tests, virulence using guinea pigs and drug susceptibility test were further explored. Finally two were identified as M. heckeshornense by summing of these results. CONCLUSION: Mycobacteria species that grow at 42 degrees C for four weeks, imply M. xenopi with a DDH method. It is essential to perform both sequencing of 16S rRNA and rpoB gene and a biochemical method for the purpose of distinguishing M. heckeshornense from M. xenopi.

Mycobacterium kansasii and M. scrofulaceum isolates from HIV-negative South African gold miners: incidence, clinical significance and radiology.

SETTING: A South African gold mining hospital. OBJECTIVE: To investigate the clinical significance of non-tuberculous mycobacteria (NTM) isolates, and estimate NTM disease incidence in human immunodeficiency virus (HIV) negative miners. DESIGN: Retrospective case series describing clinical and radiological features associated with NTM sputum isolates from HIV-negative miners between January 1993 and July 1996, and a comparison group with Mycobacterium tuberculosis infection. RESULTS: Of miners with NTM isolates, 90% had been HIV-tested and 81% were HIV-negative. M. kansasii and M. scrofulaceum accounted for 202 (68%) and 41 (14%) isolates respectively. More than 80% of miners with M. kansasii or M. scrofulaceum were smear positive, and new cavitation was present in 78% and 74% respectively. Treatment failure occurred in 3% of M. kansasii and 12% of M. scrofulaceum patients. A normal pre-morbid radiograph was significantly less common in NTM than M. tuberculosis patients (odds ratio 0.26 and 0.10 for M. kansasii and M. scrofulaceum, respectively). NTM disease incidence, defined as NTM isolate plus new cavitation, was estimated at 66 and 12 per 100000 person-years for M. kansasii and M. scrofulaceum, respectively. CONCLUSIONS: M. kansasii and M. scrofulaceum disease are common in HIV-negative South African gold miners. Most isolates are associated with new cavitation against a background of silicosis or old TB scarring.

[Coccidioidomycosis: a new brazilian case]. / Coccidioidomicose: novo caso brasileiro.

A case of pulmonary coccidioidomycosis from the rural zone of Bertolinia, PI, is reported. The patient, a farm worker, attributed his illness to the dust inhaled while digging a water well during the dry season of the year, some weeks before the onset of the clinical manifestations. The main symptoms of the disease were severe chest pain and moderate fever. The diagnosis was made histopathologically: tissue phase fungal organisms--immature spherules and spherules with endospores--were observed in histological sections of a lung fragment obtained by open chest biopsy. This is the twelfth autochthonous case of coccidioidomycosis found so far in Brazil. All of them involved native inhabitants of the semi-arid part of Northeastern Brazil. The hot and dry environment of the region seems to favor the development of C. immitis in the soil. Humans and animals probably acquire the infection by digging the soil, when they become exposed to the conidium-bearing dust raised by this activity.

[Respiratory tract infections caused by Branhamella catarrhalis in outpatients with pneumoconiosis].

To investigate the occurrence of Branhamella catarrhalis respiratory tract infections in 109 outpatients with pneumoconiosis, clinical and bacteriological studies were performed during a 4-year period from April 1984 to March 1988. B. catarrhalis was isolated in 26 patients; only three of these received continuous corticosteroid treatment. The incidence of B. catarrhalis respiratory tract infections increased gradually during the years 1984-1986, but decreased for the first time in 1987 compared with the previous year. There was a seasonal variation in isolations with a peak incidence during the winter, a pattern in contrast to Haemophilus influenzae. Almost all isolates produced beta-lactamase. B. catarrhalis found in mixed culture was usually in association with H. influenzae or Streptococcus pneumoniae. The isolation rates for B. catarrhalis in sputum of patients with pneumoconiosis followed those of H. influenzae and S. pneumoniae, and almost all strains were positive for beta-lactamase, so B. catarrhalis should be admitted that it is a primary pathogen.

[Study of organisms isolated from non-infected patients with pneumoconiosis].

Studies on the sputum organisms and their seasonal incidences were conducted on non-infected patients with pneumoconiosis. A total of 3318 organisms were isolated from 1427 sputum examinations, an average of 4 examinations per patient. alpha-Streptococcus, GPC, Neisseria and GNC were isolated in 74.1, 22.1, 64.8, 21.3% of the patients respectively. In addition, organisms to cause respiratory infection were isolated in the non-infected phase. S. pneumoniae, S. aureus, B. catarrhalis, H. influenzae, E. coli, K. pneumoniae and P. aeruginosa were isolated in 1.5, 5.1, 2.5, 3.3, 2.9, 6.4, 2.8% of the patients respectively. Studies of the seasonal incidences in these organisms showed that H. influenzae, B. catarrhalis and S. pneumoniae were isolated mostly in winter, S. aureus mostly in spring, E. coli and K. pneumoniae mostly in summer. On the other hand, P. aeruginosa showed no seasonal incidence. In relation to the causing organisms of respiratory infection with pneumoconiosis, it is very interesting that many organisms were isolated in the non-infected phase, and seasonal incidences were observed.

Sequence analysis of the drug­resistant rpoB gene in the Mycobacterium tuberculosis L­form among patients with pneumoconiosis complicated by tuberculosis.

The aim of the present study was to investigate the mutational characteristics of the drug­resistant Mycobacterium tuberculosis L­form of the rpoB gene isolated from patients with pneumoconiosis complicated by tuberculosis, in order to reduce the occurrence of the drug resistance of patients and gain a more complete information on the resistance of the Mycobacterium tuberculosis L­form. A total of 42 clinically isolated strains of Mycobacterium tuberculosis L­form were collected, including 31 drug­resistant strains. The genomic DNA was extracted, then the target genes were amplified by polymerase chain reaction and the hot mutational regions of the rpoB gene were analyzed by direct sequencing. The results revealed that no rpoB gene mutation was present in 11 rifampicin (RFP)­sensitive strains, while conformational changes were identified in 31 RFP­resistant strains. The mutation rate was 93.55% (29/31) in the resistant strains, and was frequently concentrated in codons 531 (51.61%; 16/31) and 526 (32.26%; 10/31), mainly occurring by case substitutions, including 27 unit point mutations and two two­point mutations. The novel mutation identified in codon 516 had not been previously reported. The substitution of highly­conserved amino acids encoded by the rpoB gene resulted in the molecular mechanism responsible for RFP resistance in the Mycobacterium tuberculosis L­form. This also demonstrated that the rpoB gene is diversiform.