The PTS Components in Klebsiella pneumoniae Affect Bacterial Capsular Polysaccharide Production and Macrophage Phagocytosis Resistance.

Novaria Sari Dewi Panjaitan,Hung-Chi Yang,Ren-In You,Yu-Tze Horng,Chih-Ching Chien,Po-Chi Soo

doi:10.3390/microorganisms9020335

Novaria Sari Dewi Panjaitan, Hung-Chi Yang + Show 4 more

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https://doi.org/10.3390/microorganisms9020335

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Abstract

Capsular polysaccharide (CPS) is a crucial virulence factor for Klebsiella pneumoniae infection. We demonstrated an association of CPS production with two phosphoenolpyruvate:carbohydrate phosphotransferase systems (PTSs). Deficiency of crr, encoding enzyme IIA of PTS, in K. pneumoniae enhanced the transcriptional activities of galF, wzi and gnd, which are in the cps gene cluster, leading to high CPS production. A crr mutant exhibited a higher survival rate in 1% hydrogen peroxide than the wild-type. The crr mutant showed less sensitivity to engulfment by macrophage (RAW 264.7) than the wild-type by observing the intracellular bacteria using confocal laser scanning microscopy (CLSM) and by calculating the colony-forming units (CFU) of intracellular bacteria. After long-term incubation, the survival rate of the intracellular crr mutant was higher than that of the wild-type. Deficiency of crr enhanced the transcriptional activities of etcABC which encodes another putative enzyme II complex of a PTS. Deletion of etcABC in the crr mutant reduced CPS production and the transcriptional activities of galF compared to those of the crr mutant. These results indicated that one PTS component, Crr, represses CPS production by repressing another PTS component, EtcABC, in K. pneumoniae. In addition, PTS plays a role in bacterial resistance to macrophage phagocytosis.

Highlights

Klebsiella pneumoniae, a member of the Enterobacteriasceae family, is an opportunistic pathogen that generally causes pneumonia, urinary tract infection (UTI) and bacteremia in hospitalized patients or patients with underlying diseases, such as diabetes mellitus, renal impairment and chronic liver disease [1,2,3]
By Reverse Transcription Quantitative Real-Time PCR (RT-qPCR), we found that the transcriptional activities of genes in the cps cluster were increased in the crr mutant compared to those in the wild-type
The results showed that the crr mutant displayed more extracellular matrix than the wild-type (Figure 1)

Summary

Introduction

Klebsiella pneumoniae, a member of the Enterobacteriasceae family, is an opportunistic pathogen that generally causes pneumonia, urinary tract infection (UTI) and bacteremia in hospitalized patients or patients with underlying diseases, such as diabetes mellitus, renal impairment and chronic liver disease [1,2,3]. The habitats for K. pneumoniae are ubiquitous and include humans, animals, plants, natural surface waters, and soils [4,5,6]. K. pneumoniae is reported to be a member of the gut microbiota in humans and animals, such as cows, pigs, birds, fish, house flies, and earthworms [6,7,8,9,10,11,12]. The prevalence of K. pneumoniae in animals differs among studies. K. pneumoniae was detected in 32–92% of cattle [6,13]. K. pneumoniae in a patient’s own microbiota is supposed to play a key role in K. pneumoniae infections [10,14]. The well-studied virulence factors of K. pneumoniae assisting in survival

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