Antibiotic resistance and serotypes of Pseudomonas aeruginosa isolates from Madina hospitals

A total of 75 recent distinct isolates of ps.aeruginosa were recovered from clinical specimens in three hospitals in madinah, Saudi Arabia. The minimal inhibitory concentrations [MIC] against 8 commonly antipseudomonal antibiotics were determined by an agar dilution method. Ciprofloxacin [CP], amikacin [AK], or tobramycin [TO], and imipenem [IM], and gentamicin [GM] showed the highest activity against the tested isolates. The resistance rates for CP, AK, or TO were 5%, whereas those for IM, and GM were 8, abd 17% respectively. Although aztreonam and ceftazidime exhibited comparable resistance rates of 22 and 24% respectively, cross-resistance between them was not observed nor with IM. Whereas most of strains were resistant to ceftriaxone [94%]. In contrast, strains resistant to AK or to were also resistant to GM, but the reciprocal was not true. Ps.aeruginosa isolates were further serotyped and tested for pyocin activity against 7 indicator strains. Serotype 0:6 was the commonest, and 13 serotypes were defined, though 51% of the strains were non-typable. Apart from an apparent nosocomial association in one hospital, there was no apparent correlation between serotypes, pyocin profiles, and antibiotic resistance markers, nor to the origin of the clinical specimens

Studies on locally isolated eneteropathogenic escherichia coli: relation of serotyping, antimicrobial agents resistance and colicin production

A 117 E. coli strains were isolated from 150 feces-specimens of infants suffering from severe dehydration. Of all the recovered isolates, 50 E. coli proved to belong to enteropathogenic E. coli [EPEC] of serotypes OK poly C and OB poly A. The selected EPEC isolates were tested in vitro for their susceptibility against different antibiotics by the st and ardized disc-agar diffusion method. The tested antibiotics comprised ampicillin [AP], chloramphenicol [CM], cephalothin [CR], mefoxin [FOX], tetracycline [TC], gentamicin [GM], neomycin [NM], tobramycin [TM], streptomycin [SM], rifampicin [RF], nalidixic acid [NA], and the combination, trimethoprim and sulfamethoxazole [SXT]. The results shoed that over 80% of the tested isolates exhibited the profile of multiple resistant strains of more than 5 R-markers, and 20% of them had resistance of more than 2 R- markers. Most of the strains were resistant to CM [96%], RF [90%], TC [86%], AP [84%], SXT [50%] and NM [48%], while most of them were sensitive to TM [90%], GM [88%], FOX [84%] and CR [48%]. In vitro susceptibility pattern of the isolated strains was done using five metal salts by the agar-plate dilution method. The results of such susceptibility showed that most of the strains were resistant to copper sulfate [100%], cadmium sulfate [90%] and mercuric chloride [70%]. While, most of them were sensitive to silver nitrate [98%] and phenylmercuric nitrate [82%]

Novel oxazolocoumarins as antimicrobial agents

The synthesis of new coumarins containing an oxazole ring fused to the 6,7 or 7,8 positions is described. The linear and angular 2- substituted-mercapto-pyrano-benzoxazoles and 2 substituted- amino- pyrano-benzoxazoles were prepared from vic-amino-hydroxy- coumarins. The antimicrobial examination of these compounds revealed that the angular 2-n-butyl-amino-6-methylpyrano [2,3-e] benzoxazole-8 [H]-one is the most promising antibacterial agent