title: In vitro antibacterial activity of some antihistaminics belonging to different groups against multi-drug resistant clinical isolates.
abstract: Antihistaminics are widely used for various indications during microbial infection. Hence, this paper investigates the antimicrobial activities of 10 antihistaminics belonging to both old and new generations using multiresistant Gram-positive and Gram-negative clinical isolates. The bacteriostatic activity of antihistaminics was investigated by determining their MIC both by broth and agar dilution techniques against 29 bacterial strains. Azelastine, cyproheptadine, mequitazine and promethazine were the most active among the tested drugs. Diphenhydramine and cetirizine possessed weaker activity whereas doxylamine, fexofenadine and loratadine were inactive even at the highest tested concentration (1 mg/ml). The MIC of meclozine could not be determined as it precipitated with the used culture media. The MBC values of antihistaminics were almost identical to the corresponding MIC values. The bactericidal activity of antihistaminics was also studied by the viable count technique in sterile saline solution. Evident killing effects were exerted by mequitazine, meclozine, azelastine and cyproheptadine. Moreover, the dynamics of bactericidal activity of azelastine were studied by the viable count technique in nutrient broth. This activity was found to be concentration-dependant. This effect was reduced on increasing the inoculum size while it was increased on raising the pH. The post-antimicrobial effect of 100 μg/ml azelastine was also determined and reached up to 3.36 h.
authors.affiliation: Pharmaceutical Microbiology Department, Faculty of Pharmacy , Alexandria University , Egypt.
authors.forename: Moustafa A
authors.initials: MA
authors.lastname: El-Nakeeb
authors.forename: Hamida M
authors.initials: HM
authors.lastname: Abou-Shleib
authors.forename: Amal M
authors.initials: AM
authors.lastname: Khalil
authors.forename: Hoda G
authors.initials: HG
authors.lastname: Omar
authors.forename: Omar M
authors.initials: OM
authors.lastname: El-Halfawy
keywords: Antihistaminics; Gram-negative isolates; Gram-positive isolates; bactericidal activity; bacteriostatic activity
references.citation: Ocul Immunol Inflamm. 2003 Dec;11(4):247-68
references.pmid: 14704897
references.citation: J Pharm Sci. 1984 Jun;73(6):841-3
references.pmid: 6145789
references.citation: Wien Klin Wochenschr. 1978 Oct 13;90(19):710-4
references.pmid: 99881
references.citation: J Pharm Sci. 1970 Jun;59(6):819-22
references.pmid: 5423085
references.citation: J Bacteriol. 1956 May;71(5):625
references.pmid: 13331878
references.citation: J Pharm Pharmacol. 1974 Nov;26(11):854-60
references.pmid: 4156554
references.citation: Indian J Med Res. 1989 Jul;89:233-7
references.pmid: 2807428
references.citation: J Pharm Pharmacol. 1981 Mar;33(3):136-40
references.pmid: 6116752
references.citation: Acta Microbiol Acad Sci Hung. 1976;23(1):45-54
references.pmid: 820163
references.citation: Biochem Pharmacol. 1975 Feb 1;24(3):347-50
references.pmid: 1125039
references.citation: Arzneimittelforschung. 1988 Jul;38(7):869-72
references.pmid: 2905130
references.citation: APMIS. 1993 Jun;101(6):449-54
references.pmid: 8103345
references.citation: Chem Phys Lipids. 1980 Oct;27(3):251-62
references.pmid: 7418116
references.citation: Acta Microbiol Immunol Hung. 1997;44(3):241-7
references.pmid: 9468728
references.citation: Int J Antimicrob Agents. 2001 Mar;17(3):225-8
references.pmid: 11282269
references.citation: J Antimicrob Chemother. 2001 Apr;47(4):391-8
references.pmid: 11266409
references.citation: Experientia. 1975 Apr 15;31(4):444-5
references.pmid: 804414
references.citation: J Appl Bacteriol. 1976 Oct;41(2):209-14
references.pmid: 11202
references.citation: J Pharm Sci. 1976 Jul;65(7):1053-7
references.pmid: 8628
references.citation: J Pharm Pharmacol. 1975 Nov;27(11):806-10
references.pmid: 1487
references.citation: Pharmacol Toxicol. 1987 Feb;60(2):100-3
references.pmid: 2883644
references.citation: Int Rev Neurobiol. 1964;7:231-78
references.pmid: 14289332
references.citation: Int J Antimicrob Agents. 2000 Sep;16(1):69-71
references.pmid: 11185417
references.citation: J Antimicrob Chemother. 2007 Jul;60(1):20-41
references.pmid: 17460026
references.citation: N Engl J Med. 2004 Nov 18;351(21):2203-17
references.pmid: 15548781
references.citation: J Pharm Pharmacol. 1975 Oct;27(10):754-58
references.pmid: 241788
references.citation: J Antimicrob Chemother. 2001 Jul;48 Suppl 1:5-16
references.pmid: 11420333