Abstract: Monitoring the development of antimicrobial resistance is important for the rational selection of appropriate antimicrobial drugs to initiate treatment of foals with sepsis. Objective: To identify temporal trends in antimicrobial susceptibility patterns of bacteria isolated from foals with sepsis. Methods: Retrospective review of medical records. Methods: Foals aged <30 days with a diagnosis of sepsis, confirmed by culture of bacteria, were included. Susceptibility data, expressed as minimum inhibitory concentrations (MICs) (MIC50 , MIC90 , MIC range) and percent of isolates that were susceptible to a particular antimicrobial drug, were compared for bacteria isolated from foals during 3 different time periods: 1979-1990, 1991-1997 and 1998-2010. The Cochran-Armitage trend test and the Jonckheere-Terpstra test were used for statistical analysis. Results: A total of 1091 bacterial isolates were cultured from 588 foals. Enterobacteriaceae, Actinobacillus spp. and β-haemolytic Streptococcus spp. showed a decrease in percent of isolates susceptible to gentamicin over time. Enterobacteriaceae, Actinobacillus spp. and β-haemolytic Streptococcus spp. showed an increase in MIC values for amikacin. Enterobacteriaceae showed a decrease in percent of isolates susceptible to ceftiofur. Enterococcus spp. and Pseudomonas spp. showed increased MIC values to ceftiofur. Enterobacteriaceae showed increased MIC values to ceftizoxime. Enterococcus spp. became more resistant to imipenem and showed increased MIC values to ticarcillin/clavulanic acid. In contrast, several trends in increased susceptibility were also seen. Conclusions: Based on these in vitro results, the combination of amikacin and ampicillin remains an appropriate choice for initiating treatment of sepsis in foals while awaiting culture and susceptibility test results, although increasing development of resistance to amikacin was demonstrated. The decrease in in vitro activity of ceftiofur against Enterobacteriaceae is of concern. Similarly, the development of resistance of Enterococcus spp. to imipenem is an important finding that warrants monitoring in the future. Judicious use of antimicrobials is therefore crucial.
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The research article is about how the effectiveness of various antimicrobial drugs for treating sepsis in foals has changed over time, from 1979 to 2010, due to the development of antimicrobial resistance in different bacteria.
Objective of the Research
The main objective of this study was to understand the changes in antimicrobial susceptibility patterns of bacteria causing sepsis in foals over time. This knowledge would help in making rational decisions about the appropriate antimicrobial drugs for initial treatment of sepsis in foals.
Research Methodology
The research involved a retrospective review of medical records of foals aged less than 30 days diagnosed with sepsis and confirmed through bacterial culture.
Antimicrobial susceptibility data such as minimum inhibitory concentrations (MICs) and the percentage of isolates susceptible to each antimicrobial drug were analyzed across three different time frames: 1979-1990, 1991-1997, and 1998-2010.
Special statistical tests, namely the Cochran-Armitage trend test and the Jonckheere-Terpstra test, were used for the analysis.
Major Findings
A total of 1091 bacterial isolates from 588 foals were identified and analyzed.
It was discovered that bacteria such as Enterobacteriaceae, Actinobacillus spp. and β-haemolytic Streptococcus spp. demonstrated reduced susceptibility to gentamicin over time.
These same bacteria also showed increased MIC values for amikacin, indicating declining drug effectiveness over time.
Certain bacteria like Enterococcus spp. and Pseudomonas spp. showed increased resistance to ceftiofur.
Increased resistance of Enterobacteriaceae to ceftizoxime was observed.
Moreover, Enterococcus spp. showed increased resistance to imipenem and increased MIC values to ticarcillin/clavulanic acid.
However, several trends in increased antimicrobial susceptibility were also noted.
Conclusions
Despite some bacteria showing increased resistance, the study concluded that the combination of amikacin and ampicillin continues to be effective in treating sepsis in foals, initially at least, as more detailed results from culture and susceptibility tests become available.
The research highlighted concerns over the diminishing in vitro effectiveness of ceftiofur against Enterobacteriaceae.
Another significant finding that requires future monitoring was the increased resistance of Enterococcus spp. to imipenem.
The study stressed the importance of judicious use of antimicrobials due to ongoing development of antimicrobial resistance.
Cite This Article
APA
Theelen MJ, Wilson WD, Edman JM, Magdesian KG, Kass PH.
(2013).
Temporal trends in in vitro antimicrobial susceptibility patterns of bacteria isolated from foals with sepsis: 1979-2010.
Equine Vet J, 46(2), 161-168.
https://doi.org/10.1111/evj.12130