This study sought to analyze the antimicrobial resistant phenotypes and genotypes as well as the virulence content of S. aureus isolates recovered from patients with diabetic foot infections (DFIs) in a Tunisian hospital. Eighty-three clinical samples of 64 patients were analyzed, and bacterial isolates were identified by MALDI-TOF. The antimicrobial resistance phenotypes were determined by the Kirby–Bauer disk diffusion susceptibility test. Resistance and virulence genes, agr profile, spa and SCCmec types were determined by PCR and sequencing. S. aureus was detected in 14 of the 64 patients (21.9%), and 15 S. aureus isolates were recovered. Six out of the fifteen S. aureus isolates were methicillin-resistant (MRSA, mecA-positive) (40%). The isolates harbored the following resistance genes (number of isolates): blaZ (12), erm(B) (2), erm(A) (1), msrA (2), tet(M) (2), tet(K) (3), tet(L) (1), aac(6′)-aph(2″) (2), ant(4″) (1) and fexA (1). The lukS/F-PV and tst genes were detected in three isolates. Twelve different spa-types were identified and assigned to seven clonal complexes with the predominance of agr-type III. Furthermore, the SCCmec types III, IV and V were found among the MRSA isolates. Moreover, one MSSA CC398-t571-agr-III isolate was found; it was susceptible to all antimicrobial agents and lacked luk-S/F-PV, tst, eta and etb genes. This is the first report on the prevalence and molecular characterization of S. aureus from DFIs and also the first detection of the MSSA-CC398-t571 clone in human infections in Tunisia. Our findings indicated a high prevalence S. aureus in DFIs with genetic diversity among the MSSA and MRSA isolates.

Carbapenem-resistant Pseudomonas aeruginosa (CRPA) are a global health concern. The antimicrobial resistance, virulence, and molecular typing of 57 CRPA isolated from 43 patients who attended a specific Tunisian hospital from September 2018 to July 2019 were analyzed. All but one were multidrug-resistant CRPA, and 77% were difficult-to-treat-resistant (DTR) isolates. The bla_VIM-2 gene was detected in four strains (6.9%), and among the 36 bla_GES-positive CRPA (62%), the bla_GES-5 gene was the predominant variant (86%). Three strains co-harbored the bla_VIM-2 and bla_GES-45 genes, and seven CRPA carried the bla_SHV-2a gene (14%). OprD alterations, including truncations by insertion sequences, were observed in 18 strains. Regarding the 46 class 1 integron-positive CRPA (81%), the bla_GES-5 gene was located in integron In717, while the bla_GES-29 and bla_GES-45 genes were found in two new integrons (In2122 and In4879), and the bla_VIM-2 gene was found in In1183 and the new integron In2142. Twenty-four PFGE patterns and thirteen sequence types (three new ones) were identified. The predominant serotype O:11 and exoU (81%) were mostly associated with ST235 and the new ST3385 clones. The seven bla_SHV-2a-CRPA from different patients belonged to ST3385 and the same PFGE pattern. The bla_GES-5- and bla_VIM-2 + bla_GES-45-positive CRPA recovered mostly from ICU patients belonged to the high-risk clone ST235. Our results highlight the alarming prevalence of bla_GES-5- and ST235-CRPA, the co-existence of bla_GES-45 and bla_VIM-2, and their location within integrons favoring their dissemination.