The relationships and susceptibilities of some industrial, laboratory and clinical isolates of Pseudomonas aeruginosa to some antibiotics and biocides

Abstract

Aims: To provide evidence to support or refute the hypothesis that cross-resistance between antibiotics and biocides can occur. Methods and Results: Fifty-®ve strains of Pseudomonas aeruginosa were tested for their resistance to anti-pseudomonal antibacterials. Twenty clinical, 19 industrial and 16 culture collection isolates were used. The MIC was found for the antibiotics amikacin, ceftazidime, cipro¯oxacin, gentamycin, ticarcillin, tobramycin, imipenem and polymyxin B. The MIC was also found for the biocides benzalkonium chloride and chlorhexidine. The analysis of the data was based on the production of a normal distribution of the log (MIC) plots for each antimicrobial. Strains were then labelled as resistant, intermediate or sensitive based on the mean and standard deviation of the distributions. Conclusions: In general the clinical isolates were the most recalcitrant organisms, with the industrial isolates being the most sensitive. Signi®cance and Impact of the Study: The work shows that antibiotic/biocide correlations do occur, especially with clinical strains. That such correlations were not found with industrial isolates suggests that the clinical environment is responsible for the correlation. We could infer that it is the selective pressure of antibiotic usage that differentiates the clinical environment from the industrial.

Potential Impact of Increased Use of Biocides in Consumer Products on Prevalence of Antibiotic Resistance

“…It was noteworthy that when individual taxa were analyzed separately, no significant correlation was noted. This indicates a clonal expansion of existing less-susceptible strains rather than adaptation of individual species, as has been noted in other recent studies of hospital isolates (132,144).…”

Susceptibility of Some Bacterial Contaminants Recovered from Commercial Cosmetics in Jordan to Preservatives and Antibiotics

“…The susceptibility pattern of the coagulase-negative staphylococci reported in this work is remarkably different than those determined for similar isolates incriminated as aetiologic agents of nosocomial infections [16]. Lambert et al [17] indicated that the selective pressure of antibiotic usage in hospitals accounts for the increase in antibioticpreservatives resistance. The same author found that this resistance was not quite marked among environmental and industrial isolates.…”

Adaptive Resistance to Biocides in Salmonella enterica and Escherichia coli O157 and Cross-Resistance to Antimicrobial Agents

“…Cross-resistance between antibiotics and biocides and between different biocides has been reported for P. aeruginosa by Lambert et al (11) and Murtough et al (21); however, no reports were found for E. coli O157 and Salmonella. It has been suggested that the possible linkage between resistance to antibiotics and resistance to biocides might be due to common resistance mechanisms (28); however, this hypothesis has never been proven conclusively.…”