The emergence of antibiotic-resistance in bacteria has limited the ability to treat bacterial infections, besides increasing their morbidity and mortality at the global scale. The need for ...alternative solutions to deal with this problem is urgent and has brought about a renewed interest in natural products as sources of potential antimicrobials. The wine industry is responsible for the production of vast amounts of waste and by-products, with associated environmental problems. These residues are rich in bioactive secondary metabolites, especially phenolic compounds. Some phenolics are bacteriostatic/bactericidal against several pathogenic bacteria and may have a synergistic action towards antibiotics, mitigating or reverting bacterial resistance to these drugs. Complex phenolic mixtures, such as those present in winemaking residues (pomace, skins, stalks, leaves, and especially seeds), are even more effective as antimicrobials and could be used in combined therapy, thereby contributing to management of the antibiotic resistance crisis. This review focuses on the potentialities of winemaking by-products, their extracts, and constituents as chemotherapeutic antibacterial agents.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
The spreading of antibiotic resistant bacteria is becoming nowadays an alarming threat to human and animal health. There is increasing evidence showing that wild birds could significantly contribute ...to the transmission and spreading of drug-resistant bacteria. However, data for antimicrobial resistance in wild birds remain scarce, especially throughout Africa. The aims of this investigation were to analyze the prevalence of ESBL-producing E. coli in faecal samples of wild birds in Tunisia and to characterize the recovered isolates.
One hundred and eleven samples were inoculated on MacConkey agar plates supplemented with cefotaxime (2 μg/ml). ESBL-producing E. coli isolates were detected in 12 of 111 faecal samples (10.81%) and one isolate per sample was further characterized. β-lactamase detected genes were as follows: bla
(8 isolates), bla
+ bla
(4 isolates). The ISEcp1 and orf477 sequences were found respectively in the regions upstream and downstream of all bla
genes. Seven different plasmid profiles were observed among the isolates. IncF (FII, FIA, FIB) and IncW replicons were identified in 11 CTX-M-15 producing isolates, and mostly, other replicons were also identified: IncHI2, IncA/C, IncP, IncI1 and IncX. All ESBL-producing E. coli isolates were integron positive and possessed "empty" integron structures with no inserted region of DNA. The following detected virulence genes were: (number of isolates in parentheses): fimA (ten); papC (seven); aer (five); eae (one); and papGIII, hly, cnf, and bfp (none). Molecular typing using pulsed-field gel electrophoresis and multilocus sequence typing showed a low genetic heterogeneity among the 12 ESBL-producing strains with five unrelated PFGE types and five different sequence types (STs) respectively. CTX-M-15-producing isolates were ascribed to phylogroup A (eleven isolates) and B2 (one isolate).
To our knowledge, this study provides the first insight into the contribution of wild birds to the dynamics of ESBL-producing E. coli in Tunisia.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Weissella strains have been reported to be useful in biotechnological and probiotic determinations, and some of them are considered opportunistic pathogens. Given the widespread interest about ...antimicrobial susceptibilities, transmission of resistances, and virulence factors, there is little research available on such topics for Weissella. The aim of this study was to assess the safety aspects and antimicrobial potential of 54 Weissella spp. strains from different environmental sources. Antibiotic susceptibility, hemolytic activity, horizontal transfer, and antibacterial activity were studied, as well as the detection of biogenic amine BA production on decarboxylase medium and PCR was performed. All the strains were nonhemolytic and sensitive to chloramphenicol and ampicillin. Several strains were classified as resistant to fusidic acid, and very low resistance rates were detected to ciprofloxacin, tetracycline, streptomycin, lincomycin, erythromycin, and rifampicin, although all strains had intrinsic resistance to vancomycin, nalidixic acid, kanamycin, and teicoplanin. Two BA‐producing strains (W. halotolerans FAS30 and FAS29) exhibited tyrosine decarboxylase activity, and just one W. confusa FS077 produced both tyramine and histamine, and their genetic determinants were identified. Ornithine decarboxylase/odc gene was found in 16 of the Weissella strains, although 3 of them synthesize putrescine. Interestingly, eight strains with good properties displayed antibacterial activity. Conjugation frequencies of erythromycin from Bacillus to Weissella spp. varied in the average of 3 × 10−9 transconjugants/recipient. However, no tetracycline‐resistant transconjugant was obtained with Enterococcus faecalis JH2‐2 as recipient. The obtained results support the safe status of Weissella strains, derived from environmental sources, when used as probiotics in animal feed.
Some Weissella strains presented acquired resistance, biogenic amines production, and their genetic determinants were identified. No tetracycline transconjugants were obtained with Enterococcus as recipient strain, whereas few erythromycin transconjugants were observed using Bacillus as donor. Eight strains belonging to W. confusa and W. halotolerans displayed antibacterial activity and good safety features.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Abstract The purpose of this study was to evaluate the rate of detection of coagulase negative staphylococci (CoNS) in environmental samples of 17 services in a Tunisian hospital, determining the ...antimicrobial resistance phenotypes and genotypes of recovered isolates. To our knowledge, this is the first study that determines the prevalence of CoNS with correlation of antibiotic resistance in the hospital environment in Tunisia. CoNS were obtained from 83 of the 200 tested samples (41.5%). Staphylococcus haemolyticus was the most prevalent species (45.8%), followed by S. saprophyticus (36.1%). The remaining CoNS species detected were S. epidermidis, S. cohnii, S. warneri, S. sciuri, S. simulans, S. pasteuri, S. arlettae , and S. xilosus . Methicillin-resistant CoNS were detected in 20 of the 200 tested samples (10%), and the mec A gene was demonstrated in 18 S. haemolyticus , one S. epidermidis and one S. saprophyticus isolates. Methicillin susceptible isolates were detected in 63 samples (31.5%). Antimicrobial resistance genes detected were as follows (number of isolates): erythromycin msr (A) (n = 32); erm (C) (n = 8), tetracycline tet (K) and/or tet (M) (n = 21), gentamicin aac (6′)-Ie- aph (2″)-Ia (n = 16), kanamycin ( aph (3′)-IIIa (n = 19), tobramycin ant (4′)-Ia (n = 14), and streptomycin ant (6′)-Ia (n = 3). The high frequency of detection of multi-drug-resistant CoNS in the hospital environment, especially S. haemolyticus and S. saprophyticus , is of relevance and could be due to cross-transmission between patients, staff, and environment.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
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 blaVIM-2 gene was detected in four strains (6.9%), and among the 36 blaGES-positive CRPA (62%), the blaGES-5 gene was the predominant variant (86%). Three strains co-harbored the blaVIM-2 and blaGES-45 genes, and seven CRPA carried the blaSHV-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 blaGES-5 gene was located in integron In717, while the blaGES-29 and blaGES-45 genes were found in two new integrons (In2122 and In4879), and the blaVIM-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 blaSHV-2a-CRPA from different patients belonged to ST3385 and the same PFGE pattern. The blaGES-5- and blaVIM-2 + blaGES-45-positive CRPA recovered mostly from ICU patients belonged to the high-risk clone ST235. Our results highlight the alarming prevalence of blaGES-5- and ST235-CRPA, the co-existence of blaGES-45 and blaVIM-2, and their location within integrons favoring their dissemination.
The aim of this study was to characterize the prevalence of fecal carriage of extended-spectrum beta-lactamases and carbapenemase-producing Gram-negative bacteria among healthy humans in Tunisia. ...Fifty-one rectal swabs of healthy volunteers were plated on MacConkey agar plates supplemented with cefotaxime or imipenem. The occurrences of resistance genes, integrons, and phylogroup typing were investigated using PCR and sequencing. The genetic relatedness of isolates was determined by pulsed-field-gel-electrophoresis (PFGE) and multilocus-sequence-typing (MLST). Whole-genome-sequencing (WGS) was performed for the carbapenem-resistant isolate. Sixteen ESBL-producing
isolates and one carbapenem-resistant
were detected out of the fifty-one fecal samples. The ESBL-producing
strains contained genes encoding CTX-M-15 (n = 9), CTX-M-1 (n = 3), CTX-M-27 (n = 3), and CTX-M-55 (n = 1). Three CTX-M-1-producers were of lineages ST131, ST7366, and ST1158; two CTX-M-15-producers belonged to lineage ST925 and ST5100; one CTX-M-27-producer belonged to ST2887, and one CTX-M-15-producer belonged to ST744. Six isolates contained class 1 integrons with the following four gene cassette arrangements:
(two isolates),
(two isolates),
(one isolate), and
(one isolate).
belonged to ST1095, produced IMI-2 carbapenemase, and contained
and
genes. A genome-sequence analysis of the
strain revealed new mutations in the
and
genes. Our results reveal an alarming rate of ESBL-
in healthy humans in Tunisia and the first description of IMI-2 in
In order to investigate the possible role of dogs and cats in the carriage and potential dissemination of resistant enterococci, seventy faecal samples from dogs and cats were tested for enterococci. ...Fifty-eight enterococci were recovered. Isolates were identified as Enterococcus faecium (n = 31) and E. faecalis (n = 14) E. durans (n = 6), E. casseliflavus (n = 2), E. hirae and E. gallinarum (2 isolates each). Enterococcal isolates showed resistance to ciprofloxacin (n = 35), erythromycin (n = 31), tetracycline (n = 25), kanamycin (n = 15), streptomycin (n = 13), pristinamycin (n = 11), gentamicin (n = 10), chloramphenicol (n = 8), and linezolid (n = 6). The gene erm(B) was detected in 22 out of 31 erythromycin-resistant enterococci. All tetracycline-resistant enterococci carried tet(M) and/or tet(L) genes. The gene aac(6')-Ie-aph(2″)-Ia was identified in five of high-level gentamicin-resistant isolates, the genes aph(3')-IIIa and/or aac(6')-Ie-aph(2″)-Ia in eleven high-level kanamycin-resistant isolates and the gene ant(6)-Ia in eleven high-level streptomycin-resistant isolates. Only one strain harboured cat(A) gene, and five strains contained vat(E) or vat(D) genes. Virulence genes gel(E) (21 strains), esp (11 strains) and cylA/cylB (5 strains) were detected. High genetic diversity was demonstrated among E. faecium isolates by pulsed-field gel electrophoresis (PFGE). Dogs and cats can be carriers of antibiotic-resistant enterococci in their faeces that could shed into the household environment.
This study sought to analyze the antimicrobial resistant phenotypes and genotypes as well as the virulence content of
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,
profile,
and SCC
types were determined by PCR and sequencing.
was detected in 14 of the 64 patients (21.9%), and 15
isolates were recovered. Six out of the fifteen
isolates were methicillin-resistant (MRSA,
-positive) (40%). The isolates harbored the following resistance genes (number of isolates):
(12),
(B) (2),
(A) (1),
(2),
(M) (2),
(K) (3),
(L) (1),
(6')
(2″) (2),
(4″) (1) and
A (1). The
and
genes were detected in three isolates. Twelve different
-types were identified and assigned to seven clonal complexes with the predominance of
-type III. Furthermore, the SCC
types III, IV and V were found among the MRSA isolates. Moreover, one MSSA CC398-t571-
-III isolate was found; it was susceptible to all antimicrobial agents and lacked
and
genes. This is the first report on the prevalence and molecular characterization of
from DFIs and also the first detection of the MSSA-CC398-t571 clone in human infections in Tunisia. Our findings indicated a high prevalence
in DFIs with genetic diversity among the MSSA and MRSA isolates.
The growing number of multidrug resistant strains in Tunisia has become a serious health concern contributing to high rate of mortality and morbidity. Since current antibiotics are rapidly becoming ...ineffective, novel strategies to combat resistance are needed. Recently, we demonstrated that combination of a tetracycline antibiotic with various polyaminoisoprenyl adjuvants can sustain the life span and enhance the activity of these drugs against
reference strain (PA01). In the context of our continuing studies, the effective approach of antibiotic-adjuvant was investigated against a large panel of
Tunisian clinical strains collected from the Military Hospital of Tunis. In this paper, we demonstrated that the combination of a farnesyl spermine compound
used at concentrations ranging from 2.5 to 10 µM, in the presence of doxycycline or minocycline leads to a significant decrease of
antibiotic resistance.
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