No effect of vancomycin MIC ≥ 1.5 mg/L on treatment outcome in methicillin-susceptible Staphylococcus aureus bacteraemia

Bouiller, Kévin; Laborde, Caroline; Aho, Serge; Hocquet, Didier; Péchinot, A.; Moing, Vincent Le; Bertrand, Xavier; Piroth, Lionel; Chirouze, Catherine

doi:10.1016/j.ijantimicag.2017.12.028

Cited by 8 publications

(2 citation statements)

References 30 publications

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“…If such is the case, these findings will be of increasing importance given the temporal trends in vancomycin MICs in MSSA and the slow declines in the fraction of disease caused by MRSA. It is worth acknowledging, however, that other investigators examining this issue have not found a consistent relationship between vancomycin MIC and clinical outcome in invasive staphylococcal infection (31,32). Such discrepancies in the literature might be a consequence of variability in MIC methodologies (33), definitions of primary outcomes, and/or global variability in strain types or intrinsic virulence.…”

Section: Discussionmentioning

confidence: 94%

Association of Vancomycin MIC and Molecular Characteristics with Clinical Outcomes in Methicillin-Susceptible Staphylococcus aureus Acute Hematogenous Osteoarticular Infections in Children

Kok

Vallejo

Sommer

et al. 2018

Antimicrob Agents Chemother

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Strains of methicillin-resistant (MRSA), particularly those belonging to the USA300 pulsotype, have been well described to cause severe osteoarticular infections (OAIs). A vancomycin MIC of ≥1.5 μg/ml has been demonstrated to contribute to disease severity in adults with MRSA and even methicillin-susceptible (MSSA) bacteremia. Little data exist describing the outcomes of MSSA OAIs in terms of molecular characteristics and vancomycin MIC. All patients/isolates were chosen from a surveillance study at Texas Children's Hospital (TCH). OAI isolates were identified from 2011 to 2016 and subjected to vancomycin Etests, pulsed-field gel electrophoresis (PFGE), and PCR to determine Panton-Valentine leucocidin (PVL) production and group. Two hundred fifty-two cases of OAI were identified; 183 cases were MSSA (72.6%). During the study period, a decrease in the proportion of cases secondary to MRSA was observed, declining from 37.8% to 15.9% ( = 0.02). Of the MSSA isolates, 26.2% and 23.5% were USA300 and PVL positive, respectively. An increase in the proportion of MSSA isolates with a vancomycin MIC of ≥1.5 μg/ml occurred in the study period ( = 0.004). In MSSA, an elevated vancomycin MIC was associated with multiple surgical procedures and venous thromboses, even when adjusting for empirical β-lactam use. An increase in vancomycin MIC was noted among isolates belonging to group 4 during the study period. Methicillin resistance is declining among OAI isolates at TCH. Simultaneously, vancomycin Etest MICs are increasing among MSSA isolates. Vancomycin MICs of ≥2 μg/ml are associated with adverse clinical outcomes in MSSA irrespective of antibiotic choice, suggesting that this may be a surrogate for organism virulence.

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Section: Discussionmentioning

confidence: 94%

Association of Vancomycin MIC and Molecular Characteristics with Clinical Outcomes in Methicillin-Susceptible Staphylococcus aureus Acute Hematogenous Osteoarticular Infections in Children

Kok

Vallejo

Sommer

et al. 2018

Antimicrob Agents Chemother

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“…The literature contains conflicting data regarding whether MRSA-vancomycin MICs could actually reflect the prognosis. Some studies have suggested that vancomycin MICs enabled the determination of adverse clinical outcomes (Honda et al, 2011;Han et al, 2012;Rojas et al, 2012;Hope et al, 2013), whereas others have not (Hos et al, 2017;Song et al, 2017;Adani et al, 2018;Bouiller et al, 2018). Because the MIC-guided treatment decision is controversial in low MRSA-vancomycin MICs (≤2 µg/mL), the IDSA also recommends that the actual clinical and microbiological response should be considered as a guide to treatment decisions if the MRSA-vancomycin MIC is low (Liu et al, 2011).…”

Section: Discussionmentioning

confidence: 99%

Discordance of vancomycin minimum inhibitory concentration for methicillin-resistant Staphylococcus aureus at 2 μg/mL between Vitek II, E-test, and Broth Microdilution

Kuo

Lio

Chen

et al. 2020

PeerJ

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Background Vancomycin, the first line antibiotic for methicillin-resistant Staphylococcus aureus (MRSA) bacteremia, is often administered inappropriately when MIC is greater than 2 µg/mL, including ‘susceptible’ strains. This study assessed the discordance of vancomycin minimum inhibitory concentration (MIC) for methicillin-resistant Staphylococcus aureus (MRSA). Methods In total, 229 MRSA isolates from blood cultures collected between 2009 and 2015 at a tertiary hospital in Taiwan were examined. The MICs of vancomycin were measured using Vitek 2, E-test, and standard broth microdilution at the level of 2 µg/mL. Results The geometric mean of the MICs of hospital-acquired MRSA was higher than that of community-acquired MRSA (P < 0.001), with the exact agreement rates (with broth microdilution) at 2 µg/mL being 53.6% in Vitek 2 and 86.7% in E-test. Overall, E-test (98.1%) had more categorical accordance than did Vitek 2 (94.0%; P = 0.026). Vitek 2 had a tendency to overestimate MRSA in high-MIC isolates, whereas E-test inclined underestimation in low-MIC isolates. Surprisingly, the discordance rates of MRSA vancomycin MICs were higher in hospital-acquired isolates (13.3%–17.0%) than in community-acquired isolates (6.2%–7.0%). Conclusion The Infectious Diseases Society of America recommends the use of alternative antimicrobial agents when vancomycin MIC is ≥ 2 µg/mL; in this study, only 53.6% of the isolates tested using Vitek 2 showed a high MIC in the broth microdilution method. Accurate identification of the resistance profile is a key component of antimicrobial stewardship programs. Therefore, to reduce inappropriate antibiotic use and mitigate the emergence of resistant strains, we recommend using complementary tests such as E-test or Broth microdilution to verify the MIC before administering second-line antibiotics. Strengths (1) We compared the categorical agreement between different methods measuring MRSA MICs level. (2) Physicians should incorporate this information and consider a complementary test to verify the appropriateness of the decision of shifting vancomycin to second-line antibiotic treatment to improve patients’ prognosis. (3) MRSA-vancomycin MICs at a cutoff of 2 µg/mL obtained using Vitek II exhibited a higher sensitivity level and negative predictive value than those obtained using E-test in the prediction of categorical agreement with standard broth microdilution. Limitation (1) Our research was based on a single hospital-based study. (2) The MRSA strains in this study were stored for more than 12 months after isolation. (3) We did not collect information on clinical prognosis.

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Genetic characterization of tetracycline-resistant Staphylococcus aureus with reduced vancomycin susceptibility using whole-genome sequencing

Kim,

Park,

Chung

2023

Arch Microbiol

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No effect of vancomycin MIC ≥ 1.5 mg/L on treatment outcome in methicillin-susceptible Staphylococcus aureus bacteraemia

Cited by 8 publications

References 30 publications

Association of Vancomycin MIC and Molecular Characteristics with Clinical Outcomes in Methicillin-Susceptible Staphylococcus aureus Acute Hematogenous Osteoarticular Infections in Children

Association of Vancomycin MIC and Molecular Characteristics with Clinical Outcomes in Methicillin-Susceptible Staphylococcus aureus Acute Hematogenous Osteoarticular Infections in Children

Discordance of vancomycin minimum inhibitory concentration for methicillin-resistant Staphylococcus aureus at 2 μg/mL between Vitek II, E-test, and Broth Microdilution

Genetic characterization of tetracycline-resistant Staphylococcus aureus with reduced vancomycin susceptibility using whole-genome sequencing

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