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The emergence of methicillin‐resistant Staphylococcus aureus (MRSA) several years ago highlighted the challenge of multidrug‐resistant infections, emphasizing the critical need for innovative treatment approaches. Myrtenol, known for its antibacterial and antibiofilm properties, holds promise as a potential treatment option. This study aimed to evaluate the effectiveness of myrtenol against MRSA. The collected MRSA isolates were assessed for antimicrobial susceptibility following the Clinical and Laboratory Standards Institute (CLSI) guidelines 2023. Biofilm formation by MRSA was evaluated using the tissue culture plate (TCP) technique. The minimal inhibitory concentration (MIC), minimal bactericidal concentration (MBC), and minimal biofilm inhibitory concentration (MBIC) of myrtenol against MRSA were determined both individually and in combination with antibiotics. Real‐time PCR was employed to investigate the impact of myrtenol on the expression of virulence genes (sarA, agrA, and icaD) across the isolates. In this study, MRSA was identified in 90 out of 400 cases (22.5%) of hospital‐acquired pathogens. Among the collected MRSA isolates, 53 out of 90 (59%) were found to produce biofilms. The MIC of myrtenol was comparable to the MBC across all tested isolates, they were almost the same. Combinations of myrtenol with most tested antibiotics exhibited synergistic effects exceeding 60%. Among the 53 biofilm‐producing isolates, 45 isolates (85%) expressed the sarA gene, 49% expressed the agrA gene, and all biofilm‐producing MRSA isolates (100%) expressed the icaD gene. A notable reduction in the relative quantity (RQ) values of virulence gene expression was observed after treatment with the MBIC of myrtenol across all tested isolates. Myrtenol demonstrated strong antimicrobial activity against MRSA, notably reducing the expression of key virulence genes linked to biofilm formation. This suggests its potential as a therapeutic agent for treating biofilm‐associated MRSA infections. [ABSTRACT FROM AUTHOR]

Aims In Tunisia, limited research has focused on characterizing clinical vancomycin-resistant Enterococcus faecium (VREfm). This study aimed to bridge this knowledge gap by molecular characterization of antimicrobial resistance, determining the genetic elements mediating vancomycin-resistance, and whole-genome sequencing of one representative VREfm isolate Methods and results Over 6 years (2011–2016), a total of eighty VREfm isolates responsible for infection or colonization were identified from hospitalized patients, with the incidence rate increasing from 2% in 2011 to 27% in 2016. All of these strains harbored the vanA gene. The screening for antimicrobial resistance genes revealed the predominance of ermB, tetM , and aac(6′)-Ie-aph(2′')-Ia genes and 81.2% of strains harbored the Tn 1545. Pulsed-field gel electrophoresis identified seven clusters, with two major clusters (belonging to ST117 and ST80) persisting throughout the study period. Seven Tn 1546 types were detected, with type VI (truncated transposon) being the most prevalent (57.5%). Whole-genome sequencing revealed a 3 028 373 bp chromosome and five plasmids. Mobile genetic elements and a type I CRISPR-cas locus were identified. Notably, the vanA gene was carried by the classic Tn 1546 transposon with ISL3 insertion on a rep17pRUM plasmid. Conclusion A concerning trend in the prevalence of VREfm essentially attributed to CC17 persistence and to horizontal transfer of multiple genetic variants of truncated vanA -Tn 1546. [ABSTRACT FROM AUTHOR]

In Côte d'Ivoire, the popularity of ready‐to‐eat salads has grown substantially. Despite their convenience, these products often face criticism for their microbiological safety. This research was conducted to assess the virulence and antibiotic resistance profiles of Escherichia coli (E. coli), Salmonella spp., and Staphylococcus aureus (S. aureus) isolated from salads available in hypermarkets across Abidjan. The study utilized a combination of microbiological and molecular biology techniques. Results indicated that E. coli isolates harbored virulence genes such as stx2 (50%) and ST (62.50%), though genes stx1 and LT were absent in the samples tested. In S. aureus, virulence genes detected included sea (55.55%), sec (11.110%), and sed (44.44%). The antibiotic resistance assessment revealed high resistance in E. coli to β‐lactam antibiotics, with all isolates resistant to cefuroxime (100%) and the majority to ampicillin and cefoxitin (87.5%). Most Salmonella spp. isolates were sensitive to the antibiotics tested, except for cefoxitin and ampicillin, showing resistance rates of 42.85% and 57.15%, respectively. Staphylococcus aureus demonstrated considerable resistance, particularly to cefoxitin (44.44%), benzylpenicillin (100%), and ampicillin (55.55%). In addition, resistance to aminoglycosides (55.55% to both kanamycin and gentamicin) and macrolides (66.66% to erythromycin and 55.55% to clindamycin) was noted. Resistance to various fluoroquinolones ranged between 33.33% and 55.55%. The presence of resistance genes such as blaTEM (10.52%), qnrA (2.26%), qnrB (5.26%), qnrS (5.26%), and mecA (13.15%) in E. coli and S. aureus underscores the challenge of multidrug resistance, exhibiting phenotypes such as ESBL (50%), Meti‐R (55.55%), KTG (44.44%), MLSB (44.44%), and FQ‐R (25%). These results carry significant epidemiological and public health implications, highlighting the urgent need for improved safety regulations and practices regarding ready‐to‐eat salads in urban food markets. [ABSTRACT FROM AUTHOR]

Aims This study was conducted to evaluate the in vitro activity of clinically relevant aminoglycosides and to determine the prevalence of genes encoding aminoglycoside modifying enzymes (AMEs) and 16S ribosomal RNA (rRNA) methyltransferases among aminoglycoside - resistant E. coli (n  = 61) and K. pneumoniae (n  = 44) clinical isolates. Associated resistances to beta–lactams and their bla genes as well as the genetic relatedness of isolates were also investigated. Materials and methods A total of 105 aminoglycoside-resistant E. coli (n  = 61) and K. pneumonia e (n  = 44) isolates recovered between March and May 2017 from 100 patients hospitalized in different wards of Charles Nicolle Hospital of Tunis, Tunisia, were studied. Minimal inhibitory concentrations of aminoglycoside compounds were determined by broth microdilution method. Aminoglycosides resistance encoding genes [ aph(3´)-Ia, aph(3′) IIa, aph(3´)-VIa, ant(2″)-Ia, aac(3)-IIa, aac(3)-IVa, aac(6′)-Ib, rmtA, rmtB, rmtC, armA , and npmA ] and bla genes were investigated by PCR and sequencing. Genetic relatedness was examined by multilocus sequence typing (MLST) for representative isolates. Results High rates of aminoglycoside resistance were found: gentamicin (85.7%), tobramycin (87.6%), kanamycin (78.0%), netilmincin (74.3%), and amikcin (18.0%). Most common AME gene was aac(3)-IIa (42%), followed by aac(6′)-Ib (36.2%) and aph(3′)-VIa (32.4%). The majority of isolates were resistant to beta–lactams and bla CTX-M-15 was the most common ESBL. The bla NDM-1 and bla OXA-48 were also produced by 1 and 23 isolates, respectively. Novel sequence types have been reported among our isolates and high-risk clonal lineages have been detected, such as E. coli ST43 (ST131 in Achtman MLST scheme) and K. pneumoniae (ST11/ST13). Conclusions The high prevalence of aminoglycoside resistance rates and the diversity of corresponding genes, with diverse β-lactamase enzymes among genetically heterogeneous clinical isolates present a matter of concern. [ABSTRACT FROM AUTHOR]

Background. Opportunistic infections are the second cause of death among cancer patients. This study aimed at determining the antimicrobial profile and the prevalence of extended‐spectrum beta‐lactamase (ESBL)‐gene carriage of Pseudomonas aeruginosa isolates among cancer patients at the Douala Laquintinie Hospital, Littoral Region of Cameroon. Between October 2021 and March 2023, 507 study participants were recruited among whom 307 (60.55%) were cancer patients, compared to 200 (39.45%) noncancer patients. Fifty‐eight P. aeruginosa isolates were isolated from fecal samples of forty‐five cancer patients and thirteen noncancer patients using Cetrimide agar. The antimicrobial resistance profile of the isolates was determined using the Kirby–Bauer disk diffusion method. The polymerase chain reaction was used to detect the presence of extended‐spectrum beta‐lactamase genes among P. aeruginosa isolates. P. aeruginosa showed significant resistance rates in cancer patients compared to noncancer patients to imipenem, cefotaxime, and ceftazidime, piperacillin‐tazobactam, ticarcillin‐clavulanic acid, and ciprofloxacin. The multidrug resistance (MDR) rate was significantly (p < 0.05) higher in cancer patients than in noncancer patients. The frequency of beta‐lactamase genes in the 58 ESBL‐producing P. aeruginosa isolates was determined as 72.41% for blaTEM, 37.93% for blaOXA, 74.14% for blaCTX‐M, and 44.83% for blaSHV genes. The study revealed an alarmingly high prevalence of fecal carriage of ESBL‐producing P. aeruginosa with a high rate of MDR among cancer patients. It indicates that regular monitoring and surveillance of ESBL‐producing P. aeruginosa among cancer patients are needed to improve the management of patients. [ABSTRACT FROM AUTHOR]

Acinetobacter baumannii has emerged as a main nosocomial pathogen exhibiting high rates of resistance to clinically relevant antibiotics. Six pandrug-resistant A. baumannii (PDR-A. baumannii) were recovered from three patients in a Tunisian Intensive Care Unit (ICU) between 10th and 16th of May 2018 resulting in one fatal case and raising the possibility of an outbreak. On 18th of May environmental screening of ICU surfaces was carried out. On 22nd of May a fourth patient was infected with PDR-A. baumannii and died. A second investigation was carried out for environmental screening and PDR-A. baumannii was isolated from the respirator. Antimicrobial susceptibility testing was performed according to EUCAST (2019) guidelines. MIC of colistin was determined by broth microdilution method. PCR was used to detect 14 beta-lactamases/carbapenemases and mcr (mcr-1 to mcr-5) genes. The genetic relatedness of PDR-A. baumannii isolates was determined by PFGE and MLST. Seven PDR-A. baumannii isolates were recovered from four patients, one MDR strain from wash basin, a PDR strain from hand sanitizer bottle and another PDR strain from respirator. All PDR-A. baumannii (n 5 9) harbored blaOXA-69 gene and none carried mcr. Moreover, seven carried blaGES and blaOXA-23 genes. PFGE identified four pulsotypes (A, B, C, and D) with the pulsotype A gathering seven PDR-A. baumannii isolates: six from three patients and one from hygiene sample. MLST revealed that all PDR-A. baumannii isolates of pulsotype A belonged to the pandemic clone ST2. Systematic screening of MDR and PDR-A. baumannii is highly recommended to limit dissemination of such strains in ICUs. [ABSTRACT FROM AUTHOR]

Pseudomonas aeruginosa is one of the major infectious agents in burn patients. Globally, high rates of antimicrobial resistance in P. aeruginosa have been reported, which is a cause of concern. The objective of this study was to determine the rate of resistance to carbapenems in P. aeruginosa isolates recovered from burn patients in Tunisia, to search genes encoding for carbapenemases and to determine their epidemiological markers (serotypes). A retrospective study was conducted in the Burn Intensive Care Unit (BICU) of the Trauma and Burn Centre of Ben Arous, Tunisia, and P. aeruginosa isolates collected from burn patients, from January to December 2018 were investigated. Carbapenemase screening was performed by Carbapenem Inactivation Method (CIM) and by EDTA-disk test for all carbapenem resistant isolates. Genes encoding carbapenemases (bla VIM, bla IMP, bla GES, bla NDM, and bla KPC) were investigated by PCR and selected carbapenemase genes were sequenced. During the study period, 104 non duplicated P. aeruginosa isolates were recovered. Most of them were isolated from skin samples (45.1%) and blood culture (22.1%) and belonged to O:11 (19.2%), O:12, and O:5 (12.5%, each) serotypes. High rates of resistance were observed for carbapenems (64.4%). Among the 67 carbapenem resistant isolates, 58 (86.5%) harbored bla VIM gene and 55 (82%) bla GES gene; in addition, 48 (71.6%) co-harbored bla VIM and bla GES genes. After sequencing, the bla VIM-2 and bla GES-5 gene variants were identified in seven randomly selected isolates. To the best of our knowledge, this is the first description of P. aeruginosa simultaneously harboring bla VIM-2 and bla GES-5 genes. [ABSTRACT FROM AUTHOR]

The emergence and spread of methicillin-resistant Staphylococcus aureus (MRSA) in hospitals is a major global public health concern. The current study sought to characterize 25 MRSA clinical isolates collected in a Tunisian hospital from December 2015 to September 2016, with the genetic lineages, virulence factors, and antibiotic resistance mechanisms determined for these isolates. Three spa -types were detected: t037 (23 isolates), t932, and t2235 (one isolate each). Isolates were ascribed to agr I (n  = 20), agr II (n  = 1), with four nontypeable isolates. Depending on sequence type (ST), the 25 MRSA isolates were assigned to two clonal complexes (CC8 and CC5), with a predominance of the lineage ST239-CC8 (n  = 24; 96%). All isolates belonging to CC8 had the SCC mec type III, while the unique CC5 isolate had SCC mec type IV. Antimicrobial susceptibility testing revealed high levels of resistance to aminoglycosides, tetracycline, ciprofloxacin and rifampicin for the majority of isolates belonging to the ST239-CC8 lineage. The ST149-CC5 isolate was susceptible to non-β-lactam antibiotics. One isolate harbored the tsst-1 gene (4%); however, lukS/LukF -PV, eta and etb genes were not detected. The MDR ST239-CC8 clone would seem to be widespread in this hospital. Therefore, a rigorous hygienic control system is urgently required. [ABSTRACT FROM AUTHOR]

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Aims: Molecular characterization of extended‐spectrum β‐lactamases (ESBLs) among Salmonella Kentucky and Typhimurium isolates: partial sequence analysis of the types of β‐lactamases found in these isolates, clonality, resistance and supposed emergence of ESBL‐producing strains. Methods and Results: A retrospective study surveyed the ESBLs occurring in a total of 1404 Salmonella Kentucky and Typhimurium isolates collected over a 5‐year period in Tunisia. Antimicrobial susceptibility tests, ESBL phenotype determination (double‐disc synergy) were performed. Polymerase chain reaction assays were used for the detection of β‐lactamase genes (blaTEM, blaSHV, blaOXA‐1 and blaCTX‐M), class 1 and class 2 integrases (intI1 and intI2) and the 3′ conserved segment (3′‐CS) of class 1 integron (qacEΔ1+sul1). Sequencing of amplicons of β‐lactamase genes was performed. Percentage of 9.8 of the isolates (S. Kentucky = 117, S. Typhimurium = 20) were either resistant to penicillin and had decreased susceptibility to cefotaxime or had a positive double‐disc synergy test result. Polymerase chain reaction detected that these isolates harboured one or more β‐lactamase genes (blaTEM, blaSHV, blaOXA‐1 or blaCTX‐M). TEM‐1, TEM‐34, CTX‐M15, CTX‐M9 and CTX‐M61 type ESBLs were identified through sequencing. The novel Salmonella cefotaxime‐hydrolysing β‐lactamase, CTX‐M61/TEM‐34, detected in this study showed the emergence of new CTX‐M‐type ESBLs in Tunisia. There were found 33 different multidrug resistance (MDR) patterns. Conclusion: These findings highlighted the proliferation of ESBLs and MDR in Salmonella Kentucky and Typhimurium isolates from numerous regions and sources in Tunisia, indicating an emerging public health concern. Significance and Impact of the Study: For the first time CTX‐M‐61/TEM‐34, a novel cefotaxime‐hydrolysing β‐lactamase of Salmonella had been detected. [ABSTRACT FROM AUTHOR]