33 research outputs found
Fosfomycin Susceptibility Testing Using Commercial Agar Dilution Test
No full textThe reference standard for fosfomycin antimicrobial susceptibility testing (AST) is agar dilution, but it is laborious and is not routinely used in diagnostic microbiology. In this study, we evaluated the performance of a ready-to-use commercially available agar dilution kit for fosfomycin AST (Liofilchem Diagnostics). We compared this kit with the reference standard agar dilution, performed according to the Clinical & Laboratory Standards Institute (CLSI) in 229 clinical isolates. The isolates were selected to represent both Gram-positive and Gram-negative microorganisms, with various MIC values. It consisted of 43 enterococci (E. faecalis n = 16, E. faecium n = 27), 13 methicillin-resistant S. aureus (MRSA), 118 Enterobacterales (Escherichia coli n = 94, Klebsiella pneumoniae n = 20, and Enterobacter cloacae complex n = 4), 55 Pseudomonas aeruginosa, and three ATCC isolates. Using CLSI breakpoints for enterococci for oral treatment of urinary tract infections, European Committee on Antimicrobial Susceptibility Testing (EUCAST) breakpoints for intravenous dosing for Enterobacterales and Staphylococci, and epidemiological cutoff value for P. aeruginosa, the essential agreement was 87.5%, and 99.6% after discrepancy resolution. There was no very major error, and 1.9% major error before, and 0.9% major error after resolution of discrepancies. The commercial test showed 100% reproducibility. In conclusion, in comparison to the reference standard, the ready-to-use commercially available agar dilution kit for fosfomycin AST showed excellent performance
Pseudomonas aeruginosa antimicrobial susceptibility profiles, resistance mechanisms and international clonal lineages: update from ESGARS-ESCMID/ISARPAE Group.
No full textScope: Pseudomonas aeruginosa, a ubiquitous opportunistic pathogen considered one of the paradigms of antimicrobial resistance, is among the main causes of hospital-acquired and chronic infections associated with significant morbidity and mortality. This growing threat results from the extraordinary capacity of P. aeruginosa to develop antimicrobial resistance through chromosomal mutations, the increasing prevalence of transferable resistance determinants (such as the carbapenemases and the extended spectrum β-lactamases), and the global expansion of epidemic lineages. The general objective of this initiative is to provide a comprehensive update of P. aeruginosa resistance mechanisms, especially for the extensively drug-resistant (XDR)/difficult to treat resistance (DTR) international high-risk epidemic lineages, and how the recently approved β-lactams and β-lactam/β-lactamase inhibitor combinations may affect resistance mechanisms and the definition of susceptibility profiles. Methods: To address this challenge, the European Study Group for Antimicrobial Resistance Surveillance (ESGARS) from the European Society of Clinical Microbiology and Infectious Diseases (ESCMID) launched the "Improving Surveillance of Antibiotic-Resistant Pseudomonas aeruginosa in Europe" (ISARPAE) initiative in 2022, supported by the Joint programming initiative on antimicrobial resistance (JPIAMR) network call and included a panel of over 40 researchers from 18 European Countries. Thus, an ESGARS-ISARPAE position paper was designed and the final version agreed after four rounds of revision and discussion by all panel members. Questions addressed in the position paper: To provide an update on (i) the emerging resistance mechanisms to classical and novel antipseudomonal agents, with a particular focus on β-lactams, (ii) the susceptibility profiles associated with the most relevant β-lactam resistance mechanisms, (iii) the impact of the novel agents and resistance mechanisms on the definitions of resistance profiles and (iv) the globally expanding XDR/DTR high-risk lineages and their association with transferable resistance mechanisms. Implication: The evidence presented herein can be used for coordinated epidemiological surveillance and decision-making at the European and global level
Evaluating the Clinical Relevance of Routine Sonication for Periprosthetic Hip or Knee Joint Infection Diagnosis
No full textPeriprosthetic joint infection (PJI) is a serious complication after joint arthroplasty. PJI screening and conventional cultures may be inconclusive. Sonication fluid culturing stands out as a valuable adjunct technique for PJI diagnosis. This study aims to determine the clinical relevance of routine sonication for all (a)septic revisions. All patients who underwent (partial) hip or knee revision arthroplasty between 2012 and 2021 were retrospectively reviewed. We formed three groups based on the European Bone and Joint Society PJI criteria: infection confirmed, likely, and unlikely. We analyzed clinical, laboratory, and radiological screening. Sensitivity and specificity were calculated for synovial fluid (preoperative), tissue, and sonication fluid cultures. We determined the clinical relevance of sonication as the percentage of patients for whom sonication confirmed PJI; 429 patients who underwent (partial) revision of hip or knee arthroplasty were included. Sensitivity and specificity were 69% and 99% for synovial fluid cultures, 76% and 92% for tissue cultures, and 80% and 89% for sonication fluid cultures, respectively. Sonication fluid cultures improved tissue culture sensitivity and specificity to 83% and 99%, respectively. In 11% of PJIs, sonication fluid cultures were decisive for diagnosis. This is applicable to acute and chronic infections. Sonication fluid cultures enhanced the sensitivity and specificity of PJI diagnostics. In 11% of PJI cases, causative pathogens were confirmed by sonication fluid culture results. Sonication fluid culture should be performed in all revision arthroplasties.</p
Biofilm-associated <i>S</i>. <i>aureus</i> sensitivity to combination antibiotics.
No full textThe 24 hours kinetic of biofilm fitness of MSSA ST72 strain co-incubated with maximum serum concentration of flucloxacillin (FLX) (A), vancomycin (VAN) (B), levofloxacin (LVX) (C), and clindamycin (CLI) (D) in combination with 8 μg/mL rifampicin (RIF) relative to untreated biofilm fitness. Dashed horizontal lines indicate control (untreated biofilm). Error bars represent median with range (n = 3). (TIF)</p
<i>Staphylococcus aureus</i> biofilm of MRSA strains sensitivity to various antibiotics.
No full textThe 24 hours kinetic of biofilm fitness of MRSA CC1 (A), CC8 (B), ST239 (C), and CC398 (D) co-incubated with maximum serum concentration of several bactericide (red) and bacteriostatic (blue) antibiotics relative to untreated biofilm fitness. Dashed horizontal lines indicate control (untreated biofilm). Error bars represent median with range (n = 3). (TIF)</p
<i>Staphylococcus aureus</i> biofilms of MSSA strains sensitivity to various antibiotics.
No full textThe 24 hours kinetic of biofilm fitness of MSSA CC25 (A), CC30 (B), CC45 (C), and ST72 (D) strains co-incubated with maximum serum concentration of several bactericide (red) and bacteriostatic (blue) relative to untreated biofilm fitness. Dashed horizontal lines indicate control (untreated biofilm). Error bars represent median with range (n = 3). (TIF)</p
Biofilm-associated <i>S</i>. <i>aureus</i> sensitivity to combination antibiotics.
No full textThe 24 hours kinetic of biofilm fitness of MSSA CC15 strain towards maximum serum concentration of flucloxacillin (FLX) (A), vancomycin (VAN) (B), levofloxacin (LVX) (C), and clindamycin (CLI) (D) in combination with 8 μg/mL rifampicin (RIF) was administered to 24 hour-old biofilms grown relative to untreated biofilm fitness. Dashed horizontal lines indicate control (untreated biofilm). Error bars represent median with range (n = 3).</p
Antimicrobial Peptides SET-M33L and SET-M33L-PEG Are Promising Agents Against Strong Biofilm-Forming P. aeruginosa, Including Multidrug-Resistant Isolates
No full textBackground:The antimicrobial peptides (AMPs) SET-M33L and SET-M33L-PEG were investigated against 10 clinical isolates of P. aeruginosa. Methods: Their minimum inhibitory concentrations (MICs), minimum bactericidal concentrations (MBCs), and minimum biofilm inhibitory concentrations (MBICs) were evaluated against tobramycin, ceftazidime, and polymyxin B. Results: MICs and MBCs were 7- to 100-fold lower than tobramycin, and 10- to 300-fold lower than ceftazidime. Fractional inhibitory concentration (FIC) indices showed an additive effect, while fractional bactericidal concentration (FBC) indices showed synergistic effects (FBC < 0.5) for most isolates. Conclusion: SET-M33L and SET-M33L-PEG are promising antimicrobial agents against strong biofilm-forming P. aeruginosa, including MDR isolates.</p
Group A-streptococcal infection during pregnancy
No full textGroup A-streptococcal (GAS) infection can lead to various clinical presentations and is fulminant when it reaches the deep tissues, leading to a high morbidity and mortality. The severity of postpartum GAS infections is widely known. In this case report we describe the course of disease in a pregnant patient with GAS toxic shock syndrome with initial complaints of abdominal pain, diarrhea and fetal demise at first presentation. Within 10 hours this patient died. It is important to stay vigilant for a fulminant GAS infection in pregnant patients, to recognize it quickly and treat it adequately.</p
In Vitro Elution of Gentamicin from CERAMENT® G Has an Antimicrobial Effect on Bacteria With Various Levels of Gentamicin Resistance Found in Fracture-related Infection
No full textBackground: Fracture-related infection is a serious complication after trauma. CERAMENT® G combines dead-space management with local release of gentamicin in a single-stage procedure. Bacterial resistance against antibiotics is increasing. The local effect of CERAMENT® G on bacteria resistant to systemically administered gentamicin is unknown. Questions/purposes:(1) What is the in vitro elution pattern of gentamicin from CERAMENT® G using a full washout model? (2) What is the in vitro antimicrobial activity (zone of inhibition) of CERAMENT® G against bacterial isolates found in fracture-related infection with different susceptibility levels toward gentamicin? Methods Elution of gentamicin from CERAMENT® G was determined in vitro over a period of 2 months. Elution experiments were performed in fivefold, with gentamicin being sampled in threefold at 19 different timepoints within 2 months. Antimicrobial activity was determined using the four most-frequently cultured bacterial species found in fracture-related infection: Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, and Enterobacter cloacae. For each of the species, four different isolates with a different susceptibility to gentamicin were used. According to the European Committee on Antimicrobial Susceptibility Testing, the susceptibility of each isolate was classified into four different groups: fully susceptible (minimum inhibitory concentration 0.064 to 4 mg/L), minimally resistant (minimum inhibitory concentration 4 to 16 mg/L), moderately resistant (minimum inhibitory concentration 8 to 96 mg/L), and highly resistant (minimum inhibitory concentration 24 to 1024 mg/L), depending on each organism. The antimicrobial activity of CERAMENT® G was determined according to the European Committee on Antimicrobial Susceptibility Testing disk protocol. The experiment was performed in fivefold for each isolate. The zone of inhibition was compared between each bacterial isolate and within each of the four separate species. Nonlinear regression statistics were calculated between the zone of interest and logarithmic minimum inhibitory concentration for each bacterial species. Results:After 24 hours, 95% of all available gentamicin was eluted, and gentamicin was still detectable after 2 months. CERAMENT® G showed antimicrobial activity against all bacterial species; only Staphylococcus aureus (with a minimum inhibitory concentration > 1024 mg/L) was not susceptible. The zone of interest of the different bacterial isolates was correlated with the logarithmic minimum inhibitory concentration. Conclusion:CERAMENT® G offers a bone substitute capable of releasing high levels of gentamicin within a short period of time. This study shows that CERAMENT® G has antimicrobial activity against bacterial isolates that are resistant to gentamicin when systemically administered. This finding raises the question of whether European Committee on Antimicrobial Susceptibility Testing cutoff points for systemic application are useful for the use of local CERAMENT® G. Standardized experiments to determine local antibiotic antimicrobial activity in fracture-related infection treatment are needed to form guidelines for the use of local antibiotics and ultimately improve fracture-related infection treatment. Clinical Relevance:Local concentrations of gentamicin with CERAMENT® G are much higher than when systemically administered. It seems effective against certain bacterial strains that are not affected by systemically reachable concentrations of gentamicin. CERAMENT® G might still be effective when bacteria that are resistant to systemically administered concentrations of gentamicin are occulated from patients with fracture-related infection.</p
