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Title: ANTIMICROBIAL ACTIVITIES OF THE CATHELICIDINS SMAP29 AND SMAP34 AGAINST OVINE RESPIRATORY PATHOGENS AND PSEUDOMONAS AERUGINOSA

Author
item BROGDEN, KIM
item KALFA, V - VISITING SCIENTIST,TURKEY
item MCCRAY, JR., P - UNIV.OF IOWA,IOWA CITY,IA
item TACK, B - UNIV.OF IOWA,IOWA CITY,IA

Submitted to: Annual North American Cystic Fibrosis Conference
Publication Type: Abstract Only
Publication Acceptance Date: 7/7/1999
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: SMAP29 and SMAP34 are 2 distinct sheep myeloid cathelicidins. In vitro data suggests that both peptides kill Pseudomonas aeruginosa, however, their activities against other respiratory pathogens have not been systemically investigated. Thus, the susceptibility of a panel of respiratory pathogens and P. aeruginosa (PAO1) to SMAP29 and SMAP34 was assessed. Cultures were grown in broth and adjusted to contain 103 CFU/ml PBS. A dilution susceptibility test was the used to obtain a minimalinhibitory concentration (MIC). Briefly, synthetic peptides were added (50 æl) to polystyrene plates. PBS(100 æl) and bacterial culture (50 æl) were then added sequentially to each dilution and the plates were incubated at 37 deg C for 120 min. After incubation, the number of viable bacteria was determined by culturing 150 æl from each well in triplicate (50 æl /per spot) on blood agar and incubating the plates overnight at 37 deg C. MIC values (æg/ml) were determined as the highest dilution of peptide killing 90% of the control value. All organisms tested were susceptible to SMAP29 (MIC range 0.5 to 7.9 æg/ml). SMAP34, SMAP29X (a derivative form of SMAP29), and SMAP29X-18 (an 18 amino acid congener of SMAP29X) were also very effective with MICs generally equal to or lower than that of SMAP29 for each organism. Less effective peptides for this panel of bacteria included the rodent cathelicidins rat CRAMP and mouse CRAMP, and truncated versions of SMAP29. In conclusion, a broad spectrum of ovine respiratory pathogens and PAO1 were uniformly susceptible to cathelicidin peptides. The highly active natures of SMAP29, SMAP34, and several derivatives in high salt strongly suggest that they may be efficacious in the treatment of respiratory bacterial infections.