Resistance profile of Bacteroides fragilis isolated in Brazil. Do they shelter the cfiA gene?
Bibliographic record
Abstract
The epidemiology of antimicrobial resistance of clinical isolates and human intestinal strains of Bacteroides fragilis has assumed great importance in the last few years since this microorganism, like other members of the B. fragilis group, can be responsible for the spread of resistance determinants. It is possible that the presence of B. fragilis in polluted aquatic environments might contribute to the spread of resistance. The antimicrobial resistance profile of 44 clinical B. fragilis strains isolated from 1981-1988 and 1991-1998 from the University hospital of Rio de Janeiro, and of 17 faecal and 17 polluted aquatic environmental B. fragilis strains isolated between 1991 and 1998 was determined. The susceptibility tests against penicillin, cefoxitin, imipenem, meropenem, clindamycin, chloramphenicol and metronidazole were performed by Etest in Wilkins-Chalgren agar enriched with 5% sheep blood. Motivated by some high MIC values for cefoxitin and meropenem, the cfiA gene, which codes for a metallo-beta-lactamase, was investigated among all strains, using PCR amplification. The resistance to penicillin was high in the samples from 1981 to 1988 (92.9%) and also in those from 1991 to 1998 (100%), although the MIC90 decreased from 256 mg/L to 24 mg/L. An increase in the resistance level to clindamycin and cefoxitin was seen from one decade to the other, the MIC90 values changing from 4 mg/L to 12 mg/L and from 8 mg/L to 32 mg/L, respectively. The susceptibility profile for metronidazole, chloramphenicol, imipenem and meropenem remained stable, although two clinical strains showed MICs of 6 mg/L and 8 mg/L against meropenem. Almost all human intestinal strains were resistant to penicillin and all of them were susceptible to imipenem, meropenem, chloramphenicol and metronidazole. The MICs of meropenem against two strains isolated from a polluted aquatic environment were 6 mg/L and 32 mg/L. The cfiA gene was detected in five strains, two of which were isolated from clinical specimens against which the MIC values of cefoxitin were high and three from an aquatic environment, whose susceptibility to both cefoxitin and meropenem ranged from sensitive to resistant.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".