Relationship between outer membrane protein profiles and resistance to ceftazidime, imipenem, and ciprofloxacin in Pseudomonas aeruginosa isolates from bacteremic patients.

Outer membrane protein (OMP) profiles of 122 Pseudomonas aeruginosa isolates recovered from the blood of bacteremic patients were analyzed to relate alterations in the expression of OMPs with porin activity to resistance to imipenem, ceftazidime, and ciprofloxacin. Imipenem-resistant isolates lacked or expressed reduced amounts of porin OprD. In contrast, alterations of OMP profiles were absent in most ceftazidime-resistant isolates. Six of 12 ciprofloxacin-resistant isolates had normal OMP profiles. The remaining isolates showed alterations in the expression of either OprC, OprF, or OprD. In addition, imipenem- and ceftazidime-resistant isolates displayed a beta-lactamase activity compatible with that of a group 1 chromosomal cephalosporinase.

Rapid diagnosis of pleural tuberculosis by polymerase chain reaction.

We have investigated the use of polymerase chain reaction (PCR) for the rapid diagnosis of pleural tuberculosis. The study was composed of 21 patients with pleural tuberculosis, confirmed by culture or pleural biopsy, and 86 control subjects. The PCR assay was based on detecting a 123-bp DNA segment belonging to the insertion sequence IS6110, specific of Mycobacterium tuberculosis complex. In 21 patients diagnosed with pleural tuberculosis, Ziehl-Neelsen staining was positive in three (14%) (95% CI, 7 to 21%) and pleural fluid culture in 11 (52%) (95% CI, 43 to 61%). Pleural biopsy revealed granulomas with caseous necrosis in 72%, and the culture was positive in 67% of the patients. Adenosine deaminase activity determination was positive (> 45 IU/L) in 86% (95% CI, 79 to 93%). The sensitivity and specificity for PCR was 81% (95% CI, 74 to 88%) and 100% (95% CI, 95 to 100%), respectively. All culture-positive specimens were PCR positive. We conclude that PCR is a rapid, sensitive, and specific method for the diagnosis of pleural tuberculosis. However, further prospective studies are required to properly evaluate the yield of the technique.

The utility of polymerase chain reaction (PCR) in the diagnosis of pulmonary tuberculosis.

A fragment of DNA of 123 bp belonging to insertion sequence IS6110, specific of Mycobacterium tuberculosis complex, was amplified by polymerase chain reaction (PCR) of respiratory samples, for the diagnosis of pulmonary tuberculosis. A total of 314 samples (286 sputum and 28 bronchoalveolar lavages) from 242 patients were evaluated by PCR, and the results were compared with the those obtained by acid-fast-stained smears, culture, and clinical diagnosis. Mycobacterium tuberculosis was detected by PCR in 102 of 105 patients with clinical diagnosis of pulmonary tuberculosis. All smear and culture-positive samples were PCR positive. The sensitivity of PCR, culture, and staining was 97%, 88%, and 65%, respectively, and the specificity was 100% in all cases. In ten patients with old residual lesions, but no active disease, M tuberculosis genome was detected by PCR. In our experience, PCR proved to be a useful method for the rapid diagnosis of pulmonary tuberculosis.

[The mycoplasmas isolated from respiratory specimens]. / Micoplasmas aislados de muestras respiratorias.

BACKGROUND: Mycoplasma pneumoniae is the species that is considered pathogen for respiratory tract. Other species, M. hominis and U. urealyticum, have been isolated from respiratory specimens and its aetiological relation with respiratory infections is not clear. METHODS: In this study, mycoplasma from respiratory specimens have been isolated from HIV infected patients, patients suffering from chronic bronchitis and patients with respiratory infections without any underlying disease, using SP-4 media and being identified with glucose fermentation test, guinea pig blood cells adsorption, tetrazolium reduction, urea test, arginine test, and antigenic study by an immunoassay on the colonies grown on SP-4 solid medium. RESULTS: M. hominis has been the species most frequent isolated, mainly from patients without any underlying disease and from HIV infected patients, and less frequently from patients suffering from chronic bronchitis, the differences between both groups being significative. Other Mycoplasma, no identified at he species level, have been isolated although without any significative differences. In only one case U. urealyticum has been isolated. CONCLUSIONS: No M. pneumoniae isolation was obtained.