This chapter explores the efflux pump mediated resistance
mechanism of Acinetobacter baumannii and the effect of (+) usnic acid as an
Efflux pump inhibitor with tigecycline. Among the multi-drug resistant strains,
Acinetobacter baumannii is a paramount pathogen in clinical terms, particularly
in hospital-acquired infections. Overall, this bacterium is the most associated
with nosocomial infections, particularly in intensive care units (ICUs). The
most important aspect of the infection with A. baumannii strains is their
resistance to entirely known antibiotics, suggesting the need for urgent action
by the global health care community. MDRAb isolates (n = 100) (preserved
at-70°C in trypticase-soy broth supplemented with 30% glycerol) collected
between 2017 to 2019 from two different states in India (Andhra Pradesh &
Telangana). For detection of efflux pump activity of tigecycline resistant
Acinetobacter baumannii isolates, micro broth dilution method and real-time
quantitative reverse transcription-polymerase chain reaction methods were used.
(+) usnic acid was added to tigecycline and tested by checkerboard method to
evaluate the efficacy as an efflux pump inhibitor. In this study, we demonstrated the EPI
activity of UA by using the EtBr agar cart wheel method and by reducing adeB
gene expression using qRT-PCR, which resulted in a decrease in TGC resistance
in A.baumannii. qRT-PCR analysis was done to show the down-regulation of the
efflux pump in the isolates. Out of 42 tigecycline-resistant Acinetobacter baumannii
isolates, 19 showed active efflux pump activity. All the 19 strains expressed
adeB gene. (+) Usnic acid as adjuvant showed better efficacy in lowering the
minimum inhibitory concentration when compared to conventional efflux pump
inhibitor carbonyl cyanide phenylhydrazone. Plant derived compounds can act as
an adjuvant to antibiotics, to increase the susceptibility to treat infectious
diseases.
Author(s) Details:
B. Nagaraju,
Department of Pharmacology, Government Medical College and Hospital,
Mahabubnagar, Telangana, 509001, India.
K. Fathimunnisa,
Department
of Microbiology, Government Medical College and Hospital, Mahabubnagar,
Telangana, 509001, India.
Please see the link here: https://stm.bookpi.org/ACPR-V6/article/view/13470
