The in vitro activity of twelve cephalosporins (first generation: Cephalothin, Cefazolin; second generation: Cefoxitin, Cefamandole, Cefuroxime, Cedonicid; third generation: Ceftazidime, Ceftizoxime, Cefotaxime, Cefoperazone, Ceftriaxone, Moxalactam) were studied against 146 strains of Gram negative bacilli belonging to the following families: Enterobacteriaceae Proteus vulgarius (2), P. mirabilis (5), Providencia stuartti (6), P. alkalifaciens (5), Morganella morganii (16), Serratia marcescens (14), Enterobacter cloacae (17), E. aerogenes (9), Kluyvera ascorbata (3), Citrobacter freundii (14), C. diversus (3), C. amalonaticus (1), Yersinia intermedia (1), Y. enterocolitica (2); Pseudomonadaceae: Pseudomonas aeruginosa (31), P. fluorescens (3); Neisseriacaee: Acinetobacter anitratus (3), Acinetobacter lwoffi (1); and Vibrionaceae: Aeromonas hydrophilia (4), Plesiomonas shigelloides (1), Campylobacter jejuni (5)). This investigation, which studied the activity of all the mentioned cephalosporins against each strain, suggests that resistance to the third generation cephalosporins has already emerged in such species as S. marcescens, E. cloacae, E. aerogenes, C. freundii, P. aeruginosa, P. fluorescens, A. anitratus, A. lwoffi, and Campylobacter jejuni. This resistance is most pronounced in Enterobacter spp., Serratia marcescens, and Pseudomonas aeruginosa. The second generation cephalosporins, particularly Cefoxitin and perhaps Cefuroxime, are chief inducers of resistance in Enterobacter and Serratia. In the pseudomonads difference mechanisms seem to operate than those taking place in Enterobacter-Serratia. The study also shows that resistance is not a generic characteristic in Proteus, Providencia, or Citrobacter but rather specific. Some aspects of mechanisms of resistance to cephalosporins are discussed. Concern is here indicated that at least in certain groups of bacteria, the use of the second generation cephalosporins may lead to emergence of resistance to the third generation group.
| Identifer | oai:union.ndltd.org:pacific.edu/oai:scholarlycommons.pacific.edu:uop_etds-1495 |
| Date | 01 January 1987 |
| Creators | Channing, Sally E. |
| Publisher | Scholarly Commons |
| Source Sets | University of the Pacific |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | University of the Pacific Theses and Dissertations |
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