Search Results (6)

Background/Objective: Vancomycin-resistant enterococci (VRE), particularly Enterococcus faecium (VREfm), are significant healthcare-associated infections, especially bloodstream infections (BSIs). Method: This study explored the genotypic and phenotypic characteristics of 29 VREfm isolates causing BSIs in Thailand. Bacterial species, sequence types (STs), virulence genes, and vancomycin antimicrobial-resistance genes were identified by multiplex PCR, multilocus sequence typing, and whole-genome sequencing (WGS). Antibiotic susceptibility was determined by disk diffusion, while an E-test or broth microdilution were used for daptomycin, teicoplanin, linezolid, and tigecycline. Biofilm formation was assessed using a microtiter plate assay. Results: All isolates harbored the vanA gene and exhibited resistance to ampicillin, erythromycin, norfloxacin, vancomycin, and rifampin. Resistance to ciprofloxacin, tigecycline, and nitrofurantoin was widespread as well. All isolates remained susceptible to chloramphenicol and linezolid. The majority of isolates belonged to clonal complex 17, with ST17 being predominant (21/29, 72.4%), followed by ST80 (6/29, 20.7%), ST761 (1/29, 3.4%), and ST117 (1/29, 3.4%). WGS analysis confirmed the presence of various antimicrobial resistance genes, including aac(6′)-Ii, ant-Ia, erm(B), and vanA. Additionally, virulence genes such as acm (collagen adhesin) and esp (enterococcal surface protein), which are involved in biofilm formation, were detected. Conclusion: This study provides insights into the genomic characteristics and clonal dissemination of invasive VREfm in Thailand, which is crucial for infection control and public health surveillance. Full article

Background: The use of antibiotic-loaded bone cements (ALBCs) in arthroplasty has been well established for the prevention and treatment of infections. Tigecycline (Tig), a broad-spectrum antibiotic, has shown efficacy against various pathogens, including vancomycin-resistant strains. Method: ISO and DIN mechanical and microbiological inhibition zone tests were performed on PMMA cement with manually added Tigecycline. Results: Manually adding 0.5 and 1.0 g Tigecycline to PMMA always meets the mechanical requirements of ISO and DIN standards. Mixtures containing 0.5 g were microbiologically effective for up to 7 days and those containing 1.0 g were effective for 28–42 days. Conclusion: In revision surgery, manually adding Tigecycline in doses of 0.5–1 g to 40 g of PMMA is effective against MRSA, VRE, and ESBL without negatively affecting the cement’s properties. Full article

Vancomycin-resistant enterococci (VRE) are considered one of the main nosocomial pathogens due to their increasing antibiotic resistance and ability to cause life-threatening infections in humans. This study included VRE isolates obtained from various specimens including urine, blood, faeces, wounds, sputum, and oral cavity wash. Of the 37 strains, 30 (81.1%) and 7 (18.9%) were identified by MALDI TOF as Enterococcus faecium and Enterococcus faecalis, respectively. The clinical vancomycin-resistant enterococci exhibited multi-drug resistance (MDR). Apart from vancomycin, the enterococci exhibited resistance to penicillins (89.1 to 100%), fluoroquinolones (100%), rifampicin (86.5%), tetracycline (27%), aminoglycosides (56.8 to 86.5%), quinupristin–dalfopristin (35.1%), and chloramphenicol (10.8%). Moreover, resistance to linezolid and tigecycline emerged among the tested vancomycin-resistant enterococci. The analysis of aminoglycoside modifying enzyme (AME) genes showed the presence of bifunctional aac(6′)-Ie-aph(2″)-Ia genes contributed to high-level aminoglycoside resistance (HLAR) in the E. faecalis and E. faecium isolates. The other AME gene, i.e., aph(3′)-IIIa, was also found in the VRE isolates. All strains carried the vanA gene. Enterococci from colonised gastrointestinal tracts (1/2.7%) and from infection (6/16.2%) showed cytotoxic activity against the human epithelial cell line HEp-2. Full article

Enterococcus faecalis, a leading multi-resistant nosocomial pathogen, is also the most frequently retrieved species from persistently infected dental root canals, suggesting that the oral cavity is a possible reservoir for resistant strains. However, antimicrobial susceptibility testing (AST) for oral enterococci remains scarce. Here, we examined the AST profiles of 37 E. faecalis strains, including thirty-four endodontic isolates, two vanA-type vancomycin-resistant isolates, and the reference strain ATCC-29212. Using Etest gradient strips and established EUCAST standards, we determined minimum inhibitory concentrations (MICs) for amoxicillin, vancomycin, clindamycin, tigecycline, linezolid, and daptomycin. Results revealed that most endodontic isolates were susceptible to amoxicillin and vancomycin, with varying levels of intrinsic resistance to clindamycin. Isolates exceeding the clindamycin MIC of the ATCC-29212 strain were further tested against last-resort antibiotics, with 7/27 exhibiting MICs matching the susceptibility breakpoint for tigecycline, and 1/27 reaching that of linezolid. Both vanA isolates confirmed vancomycin resistance and demonstrated resistance to tigecycline. In conclusion, while most endodontic isolates remained susceptible to first-line antibiotics, several displayed marked intrinsic clindamycin resistance, and MICs matched tigecycline’s breakpoint. The discovery of tigecycline resistance in vanA isolates highlights the propensity of clinical clone clusters to acquire multidrug resistance. Our results emphasize the importance of implementing AST strategies in dental practices for continued resistance surveillance. Full article

Background and Objectives: Vancomisin-resistant Enterococci (VRE), is a resistant microorganism that colonizes and causes infections in hospitalized patients. The aim of this study was to show the spread of vancomycin-resistant Enterococcus faecium (VREfm) step-by-step in all intensive care units, which started with the growth of VREfm on 2 December 2021 in the blood culture of a patient hospitalized in the anesthesia intensive care unit of our hospital and was found to have reached epidemic size in the surveys. Materials and Methods: Rectal swab samples were taken from all patients hospitalized in intensive care units, VRE colonization was determined, the VanA and VanB resistance genes associated with the vancomycin resistance of VREfm isolates were determined by PCR method, and clonal association analysis was performed by Arbitrarily Primed-PCR (AP-PCR) and PFGE (pulsed-field gel electrophoresis). Results: In our study, VRE were detected in 61 of 2601 rectal swab samples. In total, fifty-four (85.52%) of the VRE isolates were Enterococcus faecium, three (4.91%) was Enterococcus faecalis, three (4.91%) was Enterococcus gallinorum, and one (1.63%) was Enterococcus casseliflavus. It was determined that all of the 54 VREfm isolates, which were the most detected among all VRE isolates, carried the vanA gene. In the clonal association analysis of the isolates by AP-PCR and PFGE methods, it was found that they had 12 different genotypes, 48 of them were included in any cluster, the clustering rate was 88.8%, and the largest cluster was the genotype 1 cluster, with 36 isolates. Of the 54 patients with VREfm isolated recently, 18.51 percent of the clinical samples were isolated before the survey, and 9.25% were isolated after the survey. It was determined that 100% of VREfm isolates were resistant to ampicillin, levofloxacin, ciprofloxacin, high-level gentamicin, trimethoprimsulfamethoxazole, and teicoplanin, 7.4% to tigecycline, and 1.85% to linezolid. Conclusions: In our study, in the clonal association analysis performed by isolating VREfm in rectal swab samples, it was found that 88.8% of the samples were indistinguishably similar, and that the increase in the number of VREfm infections after the index case in our hospital was associated with the epidemic. VREfm infections cause long-term hospitalization, costs and also deaths, which shows the seriousness of the event, and the importance of the combination of epidemiological and molecular analysis in epidemic research. Full article

Due to the extensive use of antimicrobial agents in human and veterinary medicine, residues of various antimicrobials get into wastewater and, subsequently, surface water. On the one hand, a combination of processes in wastewater treatment plants aims to eliminate chemical and biological pollutants; on the other hand, this environment may create conditions suitable for the horizontal transfer of resistance genes and potential selection of antibiotic-resistant bacteria. Wastewater and surface water samples (Morava River) were analyzed to determine the concentrations of 10 antibiotics and identify those exceeding so-called predicted no-effect environmental concentrations (PNECs). This study revealed that residues of five of the tested antimicrobials, namely ampicillin, clindamycin, tetracycline, tigecycline and vancomycin, in wastewater samples exceeded the PNEC. Vancomycin concentrations were analyzed with respect to the detected strains of vancomycin-resistant enterococci (VRE), in which the presence of resistance genes, virulence factors and potential relationship were analyzed. VRE were detected in 16 wastewater samples (11%) and two surface water samples (6%). The PNEC of vancomycin was exceed in 16% of the samples. Since the detected VRE did not correlate with the vancomycin concentrations, no direct relationship was confirmed between the residues of this antimicrobials and the presence of the resistant strains. Full article