The effect of exposure to sub-inhibitory concentrations of hypochlorite and quaternary ammonium compounds on antimicrobial susceptibility of Pseudomonas aeruginosa.

BACKGROUND: Pseudomonas is a group of medically important species that inhabit a wide range of niches, including hospital environments. Controversies have emerged about the possible link between improper use of disinfectants and the emergence of antibiotic resistance in bacteria. The aim of this study was to assess the effect of exposure of antibiotic-susceptible Pseudomonas isolates to sub-inhibitory concentrations of 2 disinfectants-didecyldimonium chloride and sodium hypochlorite-on their antibiotic susceptibility patterns. METHODS: This study involved 50 Pseudomonas isolates. The antibiotic susceptibility patterns of the isolates were assessed using broth microdilution method. The minimal inhibitory concentrations (MICs) of each antibiotic were compared before and after exposure to sub-inhibitory concentrations of didecyldimonium chloride and sodium hypochlorite. RESULTS: After overnight incubation with sub-inhibitory concentrations of sodium hypochlorite, a statistically significant increase was observed in the MICs of colistin (P = .012), ceftazidime (P < .001), amikacin (P < .001), meropenem (P < .001), gentamicin (P < .001), piperacillin-tazobactam (P = .003), and ciprofloxacin (P = .004). In contrast, exposure to sub-inhibitory concentrations of didecyldimonium chloride showed a statistically significant increase in the MICs of amikacin (P < .001), gentamicin (P < .001), meropenem (P = .041), and ciprofloxacin (P = .008). CONCLUSIONS: The use of suboptimal concentrations of sodium hypochlorite and didecyldimonium chloride can lead to the evolution of antibiotic-resistant Pseudomonas strains.

Entomophthoromycosis: a challenging emerging disease.

Entomophthoromycosis is a rare fungal infection that may affect immunocompetent hosts; predominantly in tropical and subtropical regions. Recently, the importance of this emerging mycosis has increased and the scope of its manifestations has been expanded. These manifestations; however, may masquerade as other clinical entities. Prompt diagnosis of this infection requires a high index of suspicion. Although histopathological examination and cultures are the gold standard diagnostic tools; molecular diagnosis is now available and started to play an important role. The cornerstone treatment is prolonged anti-fungal therapy along with surgical debridement. More awareness of this mycosis is warranted for definitive diagnosis and implementation of early proper therapeutic strategies.