Is gentamicin necessary in the antimicrobial treatment for group B streptococcal infections in the elderly? An in vitro study with human blood products.
Publisher DOI
PubMed ID
27766925
Abstract
BACKGROUND
According to expert opinions, gentamicin should be administered as an adjunct to penicillin against severe group B streptococcal (GBS) infections. Whether the adjunct is important is of particular interest for elderly patients. Not only is the risk of aminoglycoside nephrotoxicity higher in elderly persons, but their immune defence to bacterial infections may also be impaired.
METHOD
Time-kill assays with human blood products, such as serum, neutrophilic granulocytes (opsonophagocytic assays) and whole blood from healthy, elderly volunteers were performed to evaluate the effect of gentamicin in combination with penicillin.
RESULTS
In time-kill assays with human serum and in opsonophagocytic assays, we saw a trend for faster killing with the penicillin-gentamicin combination therapy. This effect was seen 4 and 6 h after antibiotic exposure but not at time points evaluated at ≥8 h. In whole blood killing assays, no difference in killing rates was observed with adjunctive gentamicin therapy.
CONCLUSION
The criteria for synergism were not fulfilled when the effect of penicillin-gentamicin combinations was compared with that of penicillin monotherapy. Rapid killing of GBS within the first few hours was observed in time-kill assays with human blood products. Considering that elderly people are prone to gentamicin nephrotoxicity and that in severe GBS infection a high penicillin dose is administered every 4-6 h, the prolonged use of adjunctive aminoglycosides in these infections requires caution.
According to expert opinions, gentamicin should be administered as an adjunct to penicillin against severe group B streptococcal (GBS) infections. Whether the adjunct is important is of particular interest for elderly patients. Not only is the risk of aminoglycoside nephrotoxicity higher in elderly persons, but their immune defence to bacterial infections may also be impaired.
METHOD
Time-kill assays with human blood products, such as serum, neutrophilic granulocytes (opsonophagocytic assays) and whole blood from healthy, elderly volunteers were performed to evaluate the effect of gentamicin in combination with penicillin.
RESULTS
In time-kill assays with human serum and in opsonophagocytic assays, we saw a trend for faster killing with the penicillin-gentamicin combination therapy. This effect was seen 4 and 6 h after antibiotic exposure but not at time points evaluated at ≥8 h. In whole blood killing assays, no difference in killing rates was observed with adjunctive gentamicin therapy.
CONCLUSION
The criteria for synergism were not fulfilled when the effect of penicillin-gentamicin combinations was compared with that of penicillin monotherapy. Rapid killing of GBS within the first few hours was observed in time-kill assays with human blood products. Considering that elderly people are prone to gentamicin nephrotoxicity and that in severe GBS infection a high penicillin dose is administered every 4-6 h, the prolonged use of adjunctive aminoglycosides in these infections requires caution.
Date Issued
2017
Publication Type
Article
Subjects
Group B Streptococcus
•
Streptococcus agalactiae
•
aminoglycosides
•
gentamicin
•
synergism
Language(s)
en
Author(s)
Additional Credits
Journal
Infectious diseases
Publisher
Taylor & Francis
ISSN
2374-4243
Access(Rights)
metadata.only