Kill rate of mastitis pathogens by a combination of cefalexin and kanamycin

Abstract

Aim: To assess the bacterial killing rate produced by a combination of cefalexin and kanamycin at two different concentration ratios. Methods and Results: Time–kill kinetics of cefalexin and kanamycin, individually and in combination, were determined against one strain each of Escherichia coli, Staphylococcus aureus, Streptococcus agalactiae, Streptococcus dysgalactiae and Streptococcus uberis. The combination was tested using two fixed ratios (cefalexin : kanamycin ratios of 1·25 : 1 and 1 : 2·3) and two concentrations of each ratio. Time–kill curves produced with either ratio were quite similar. Against most bacterial species, higher concentrations produced faster kill. In all cases, the combination of cefalexin and kanamycin showed faster and greater kill at lower antibiotic concentrations than those observed with either drug alone. Conclusions: The combination of cefalexin and kanamycin results in a fast initial killing of major mastitis pathogens at both concentration ratios. Significance and Impact of the Study: The combination of cefalexin and kanamycin achieved rapid bacterial kill at concentrations and ratios that can be achieved in vivo following intramammary infusion of a mastitis treatment.

Susceptibility of coagulase-negative staphylococci to a kanamycin and cefalexin combination

“…This combination offers an extended spectrum of activity compared with that of each individual drug. The 2 antimicrobials have been shown to demonstrate synergy against major mastitis pathogens such as Staphylococcus aureus, Streptococcus uberis, and Escherichia coli, offering potential for increased efficacy compared with using either of the antibiotics alone (Ganiere and Denuault, 2009;Maneke et al, 2011). Combination therapy can also be useful in situations in which resistance of a particular target pathogen to one agent has emerged but susceptibility to the other agent persists (Pillar et al, 2009).…”

Kill Rate and Evaluation of Ex Vivo PK/PD Integration of Cefquinome Against Actinobacillus pleuropneumoniae

“…They showed that the effect of cefquinome was time-dependent, but that the kill rate and drug concentration had no obvious correlation. Maneke et al ( 31 ) compared the kill rate of cefalexin and kanamycin alone or combination against five mastitis pathogens. The results show that the higher concentrations can produce faster kill for most strains.…”

Live-imaging rate-of-kill compound profiling for Chagas disease drug discovery with a new automated high-content assay

“…When assessing combination treatment, it may be valuable to determine the rate-of-kill of the PLOS NEGLECTED TROPICAL DISEASES combination as well as individual partner drugs, as some combinations may achieve a faster rate-of-kill than any of the partners individually (e.g. [29]). Such combinations would offer the potential of shorter treatment regimens.…”