Antimicrobial Activity of the Iron-Chelator, DIBI, against Multidrug-Resistant Canine Methicillin-Susceptible Staphylococcus pseudintermedius: A Preliminary Study of Four Clinical Strains

Abstract

Staphylococcus pseudintermedius is an important opportunistic pathogen causing various infections in dogs. Furthermore, it is an emerging zoonotic agent and both multidrug-resistant methicillin-resistant S. pseudintermedius (MRSP) as well as methicillin-susceptible (MSSP) strains represent an important therapeutic challenge to veterinary medicine and pose a potential threat to human health. We tested representative S. pseudintermedius clinical strains from dogs suffering from otitis externa for their susceptibilities to a panel of 17 antimicrobials compared to DIBI. DIBI, unlike antibiotics, is a novel water-soluble hydroxypyridinone-containing iron-chelating agent that deprives microbes of growth-essential iron and has been previously shown to inhibit methicillin-resistant Staphylococcus aureus (MRSA). We also characterised the strains according to whether they harbour key antibiotic resistance genes. The strains each displayed multiple antimicrobial resistance patterns; all were negative for the mecA gene and possessed the tetK and tetM genes, but they varied as to their possession of the ermB gene. However, all the isolates had similar susceptibility to DIBI with low MICs (2 µg/mL or 0.2 µM). Because the four MSSPs were equally susceptible to DIBI, subject to confirmation with additional strains, this could provide a potential non-antibiotic, anti-infective alternative approach for the treatment of antimicrobial-resistant canine S. pseudintermedius otitis.

Effects of Piper betle Extracts against Biofilm Formation by Methicillin-Resistant Staphylococcus pseudintermedius Isolated from Dogs

“…Furthermore, the presence of mecA significantly affects the antibiotic resistance of S. pseudintermedius [ 47 ]. Our findings are consistent with those of other studies [ 38 , 48 ]. MRSP isolates exhibited multidrug resistance, all isolates of the MRSPs being resistant to ampicillin; 80% resistant to oxacillin, cefotaxime, and sulfamethoxazole/trimethoprim; 70% resistant to norfloxacin, enrofloxacin, and doxycycline; and 60% resistant to amoxicil-lin–clavulanic acid, ceftriaxone, gentamicin, and erythromycin.…”

The Iron Chelator, DIBI, Reduces Bacterial Load and Inflammation in Experimental Lung Infection

“…DIBI treatment was efficient in reducing bacterial load in both lung homogenate and BALF. In agreement with our findings on DIBI-restricted P. aeruginosa growth, it has previously been demonstrated that iron-withdrawal chelator DIBI has also been shown to disrupt the staphylococcal biofilm growth [18]. In previous studies published by our group we found that in sepsis induced by colon ascendens stent peritonitis (CASP), DIBI treatment significantly decreased the bacterial count in blood and peritoneal lavage fluid [19].…”

Multidrug-Resistant Commensal and Infection-Causing Staphylococcus spp. Isolated from Companion Animals in the Valencia Region

“…Dogs and cats were sampled between October 2022 and June 2023 in order to isolate Staphylococcus spp. To isolate commensal Staphylococcus , a single swab (Cary–Blair sterile transport swabs, DELTALAB, Barcelona, Spain) was first introduced in the nasal cavity and then in the auricular cavity, approximately 3 cm [ 25 , 26 ], from healthy asymptomatic dogs and cats. Before taking the samples, the veterinarians performed a clinical examination in which they assessed the animals’ vital signs to confirm that they were within normal ranges, thus classifying them as asymptomatic healthy animals.…”