Abstract
Honeybees (Apis mellifera) are environmentally and economically important
insects, although their colonies are infected with a number of bacterial pathogens,
including Klebsiella oxytoca, a Gram-negative bacterium that belongs to the
Enterobacteriaceae family, that may contribute to the decline in the health of
honeybees. The aim of this study was to assess the antibacterial activity of zinc oxide
nanoparticles (ZnO NPs) against K. oxytoca, which was isolated from honeybees, in
vitro. Samples were collected from a number of beehives from different places in Al-
Diwaniyah Governorate, Iraq. Isolates were diagnosed using culture and biochemical
tests, in addition to a confirmation diagnosis by the VITEK® 2 Compact System and
16S rRNA gene amplification. The 96-well microtiter plate method was used to
evaluate the effectiveness of various ZnO NP concentrations (0, 10, 100, and 500
μg/ml). The results showed that ZnO NPs have effective inhibition on K. oxytoca. The
concentration of 500 μg/mL was the most effective, with significant variations at the
P < 0.05 level. These results show that ZnO NPs could be a good choice instead of
antimicrobials used to control diseases caused by bacteria in honeybees.
insects, although their colonies are infected with a number of bacterial pathogens,
including Klebsiella oxytoca, a Gram-negative bacterium that belongs to the
Enterobacteriaceae family, that may contribute to the decline in the health of
honeybees. The aim of this study was to assess the antibacterial activity of zinc oxide
nanoparticles (ZnO NPs) against K. oxytoca, which was isolated from honeybees, in
vitro. Samples were collected from a number of beehives from different places in Al-
Diwaniyah Governorate, Iraq. Isolates were diagnosed using culture and biochemical
tests, in addition to a confirmation diagnosis by the VITEK® 2 Compact System and
16S rRNA gene amplification. The 96-well microtiter plate method was used to
evaluate the effectiveness of various ZnO NP concentrations (0, 10, 100, and 500
μg/ml). The results showed that ZnO NPs have effective inhibition on K. oxytoca. The
concentration of 500 μg/mL was the most effective, with significant variations at the
P < 0.05 level. These results show that ZnO NPs could be a good choice instead of
antimicrobials used to control diseases caused by bacteria in honeybees.
Keywords
Honeybee Apis mellifera Klebsiella oxytoca ZnO Nanoparticles