Phages from Ganges River curtail in vitro biofilms and planktonic growth of drug resistant Klebsiella pneumoniae in a zebrafish infection model

Abstract

Bacteriophages are a promising alternative for curtailing infections caused by multi drug resistant (MDR) bacteria. The objective of the present study is to evaluate phage populations from water bodies to inhibit planktonic and biofilm mode of growth of drug resistant Klebsiella pneumoniae in vitro and curtail planktonic growth in vivo in a zebrafish model. Phage specific to K. pneumoniae (MTCC 432) was isolated from Ganges River (designated as KpG). One-step growth curve, in vitro time kill curve study and in vivo infection model were performed to evaluate the ability of phage to curtail planktonic growth. Crystal violet assay and colony biofilm assay were performed to determine the action of phages on biofilms. KpG phages had a greater burst size, better bactericidal potential and enhanced inhibitory effect against biofilms formed at liquid air and solid air interfaces. In vitro time kill assay showed a 3 log decline and a 6 log decline in K. pneumoniae colony counts, when phages were administered individually and in combination with streptomycin, respectively. In vivo injection of KpG phages revealed that it did not pose any toxicity to zebrafish as evidenced by liver/brain enzyme profiles and by histopathological analysis. The muscle tissue of zebrafish, infected with K. pneumoniae and treated with KpG phages alone and in combination with streptomycin showed a significant 77.7% and 97.2 % decline in CFU/ml, respectively, relative to untreated control. Our study reveals that KpG phages has the potential to curtail plantonic and biofilm mode of growth in vivo in higher animal models.

Antibiotic resistance, virulence-associated genes analysis and molecular typing of Klebsiella pneumoniae strains recovered from clinical samples

“…The biofilm-forming ability in K. pneumoniae allows the protection of strains from the host immune response and antibiotics in MDR isolates (Sundaramoorthy et al 2021 ) and different biofilm-related genes including mrk (type 3 fimbriae), fimH-1 (type 1 fimbrial adhesion) are involved in the biofilm formation (Sahoo et al 2019 ; Ranjbar et al 2019 ). It was shown that the efflux pumps play an important role in antibiotic resistance and biofilm formation (Tang et al 2020 ).…”