Evaluation of the synergistic effect of tomatidine with several antibiotics against standard and clinical isolates of staphylococcus aureus, enterococcus faecalis, pseudomonas aeruginosa and escherichia coli

Antibiotic resistance is an important problem in antibiotic treatment of infections, particularly in hospitals. Tomatidine is a plant secondary metabolite with antimicrobial and antifungal effects. This study examined the possible synergistic effect tomatidine with several antibiotics against standard and clinical strains of Staphylococcus aureus, Enterococcus faecalis, Pseudomonas aeruginosa and Escherichia coli. After determining the minimum inhibitory concentrations [MICs] of antibiotics and tomatidine against the bacterial isolates using broth microdilution method, the synergistic effect between tomatidine and antibiotics was evaluated by checkerboard method and calculation of FIC indices. Tomatidine alone did not show any antimicrobial effect. However, it had synergistic effect with gentamicin and cefepime against standard and clinical isolates of S. aureus and P. aeruginosa, respectively. It also had synergistic effect with ampicillin and ciprofloxacin only against standard strains of E. faecalis and P. aeruginosa, respectively. In conclusion, tomatidine could be considered as a potential antibiotic potentiator for gentamicin, cefepime and ciprofloxacin, and ampicillin against Staphylococcus aureus, Pseudomonas aeruginosa, and Enterococcus faecalis infections, respectively. However, the toxicological and pharmacological properties of tomatidine for use as a therapeutic agent remain to be determined

Identification of class-1 integron and various b-lactamase classes among clinical isolates of Pseudomonas aeruginosa at Children's Medical Center Hospital

Pseudomonas aeruginosa is one of the most important opportunistic pathogens responsible for various types of infections. Children suffer significant morbidity and mortality due to nosocomial infections. The aim of this study was to investigate the presence of Class-1 integron, bla[BEL], bla[PER], bla[kpc], bla[VIM],bla[IMP] and bla[OXA] A-group-1 genes among P. aeruginosa isolates at Children's Medical Center Hospital in Iran and to determine phenotypic evidence of ESBL and MBL production. Antibiotic susceptibility tests were analyzed for 72 P. aeruginosa clinical isolates. Isolates were identified by using biochemical tests and confirmed by PCR assay for oprL gene. ESBL and MBL producer isolates were identified by phenotypic tests [double disc synergy tests]. Detection of beta-lactamase genes and class-1 integron were performed by PCR method. All of the isolates were susceptible to ceftazidime / clavulanate, me-ropenem, imipenem and ciprofloxacin. About 83.3% and 16.7% of isolates were resistant to ceftazidime and amikacin respectively. Approximately, 83.3% of isolates were considered as potential ESBL producers. None of the clinical isolates showed above P-lactamase genes. It seems that, the reason is the absence of class-1 integron in all of isolates. About 16.7% of strains were identified as multidrug resistant. Fortunately, all of the isolates were susceptible to meropenem and imipenem which are effective against ESBL producing strains. The absences of class-1 integron decreases the probability of acquired beta-lactamase especially MBL. Thus, absolute susceptibility to carba-penems and ciprofloxacin among P. aeruginosa isolates in pediatric hospital has important implications for empirical antimicrobial therapy. It seems that these properties help to decrease mortality of nosocomial infections within children