Antibiograms and Lipid Contents of Pigmented and Nonpigmented Strains of Serratia marcescens

Abstract

The antibiogram of pigmented 08 and nonpigmented Bizio strains of Serratia marcescens was determined. Their lipid content was also analyzed.

Antibiogram and Lipid Analysis of a Pigmented Strain of Serratia marcescens and Its Nonpigmented Variants

“…However, our results of this and other studies (15) do not seem to strongly support the implication that pigmented cells in general are more susceptible to antibiotics (5,22). The study of Winshell and Neu (22) seemed to indicate that clinical isolates of pigmented strains of different bacteriocin types were generally more susceptible to diverse antibiotics than were nonpigmented strains.…”

“…The study of Winshell and Neu (22) seemed to indicate that clinical isolates of pigmented strains of different bacteriocin types were generally more susceptible to diverse antibiotics than were nonpigmented strains. Normally in S. marcescens a nonpigmented organism is not necessarily more resistant (15). When a pigmented organism is resistant to multiple antibiotics, such as strain 08, the loss of the ability for pigment formation in its variants (isolates M-1 and M-2) does not concomitantly induce any change in the level of antibiotic susceptibility.…”

“…A serial twofold broth dilution method was used to determine minimal inhibitory concentration (MIC) in tryptic soy broth (11,15). Six-hour cultures were diluted 1:1,000 before addition of 0.05 ml (10' cells) to the twofold antibiotic broth dilution.…”

Antibiotic Resistance Patterns of Clinical Isolates of Serratia marcescens

“…Serratia strains isolated from different hospitals often appear to have characteristic resistance patterns (13). Other studies have provided conflicting results concerning resistance patterns of pigmented versus nonpigmented strains (2,11).…”

“…The ability of this opportunistic pathogen to acquire resistance to a broad range of antibiotics has made effective therapy more difficult. Several recent investigations have dealt with the problem of antibiotic resistance in Serratia (3,4,6,(10)(11)(12)(13). The overall findings of these studies indicate that the polymyxins and cephalosporins are the least effective agents against Serratia in vitro, and although gentamicin, kanamycin, chloramphenicol, and nalidixic acid are the most effective, resistance to kanamycin and chloramphenicol, as well as the p-lactam antibiotics, has increased during the last decade.…”