Abstract
The unusual frequency of pulmonary colonization of cystic fibrosis patients by mucoid (mu+) strains of P. aeruginosa suggests a special relationship between these strains and the pulmonary milieu of CF patients. To better characterize the control of slime production, we isolated P. aeruginosa from sputum cultures of CF patients collected during respiratory therapy. 16 of 19 patients yielded P. aeruginosa which was identified by the API method with growth at 41° and on Pseudomonas isolation agar. Mu+ strains were isolated from 13 of 16 pattents; 11 of 16 had both mu+ and nonmucoid (mu−) strains. All 13 mu+ strains were unstable in nutrient broth, producing mu− variants at characterisic frequencies ranging from 1-97% of c.f.u. in 24 hours. Mu− segregation frequency is medium-and temperature-dependent. The low frequency (<1×10-5) of reversion of mu− to mu+ suggests inherited loss of the capacity to produce slime. 2 of 13 mu+ strains showed concomitant loss of slime production and selected anti-biotic resistance on Mueller-Hinton agar. Each of 10 independently derived mu−clones from VLO-1 became bactrim sensitive; MIC by the agar dilution method for trimethoprim and sulfamethoxazole were respectively 64 and 160μg/ml for VLO-lmu+ vs 8 and 40μg/ml for VLO-1mu−. Strain TWH-1mu− showed a similar increase in sensitivity to chloramphenicol. This suggests that slime production is encoded by a plasmid which also specifies resistance to certain antibiotics.
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Seale, T., Tarpay, M., Thirkill, H. et al. 815 CONCOMITANT LOSS OF MUCOID TRAIT AND ANTIBIOTIC RESISTANCE IN PSEUDOMONAS AERUGINOSA STRAINS FROM CYSTIC FIBROSIS PATIENTS. Pediatr Res 12 (Suppl 4), 499 (1978). https://doi.org/10.1203/00006450-197804001-00820
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DOI: https://doi.org/10.1203/00006450-197804001-00820