Positive control of colanic acid synthesis in Escherichia coli by rmpA and rmpB, two virulence‐plasmid genes of Kiebsiella pneumoniae

Nassif, Xavier; Honoré, Nadine; Vasselon, Thierry; Cole, Stewart T.; Sansonetti, Philippe J.

doi:10.1111/j.1365-2958.1989.tb00116.x

Cited by 101 publications

(101 citation statements)

References 39 publications

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“…The presence of aerobactin is always associated with a hypercapsule, although not all hypercapsulated strains possess this siderophore (227,311,335). This association is due to the fact that the aerobactin gene cluster, iucABCD, along with the aerobactin transporter iutA are carried on the same virulence plasmid that carries rmpA, an enhancer of capsule production (215,319,(336)(337)(338). Interestingly, while aerobactin is found only rarely in classical strains causing lung infection, it may be the predominant siderophore expressed in certain HV K. pneumoniae strains causing lung infection (331).…”

Section: Figmentioning

confidence: 99%

“…In fact, 55 to 100% of HV K. pneumoniae strains express at least one copy of rmpA or rmpA2, compared to 7 to 20% of non-HV K. pneumoniae strains (47,214). These genes positively regulate the cps locus at the transcriptional level, resulting in the hypercapsule phenotype (202,(215)(216)(217). However, not all of these genes must be upregulated or even present concurrently (214,216,218,219).…”

Section: Capsulementioning

confidence: 99%

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Klebsiella pneumoniae: Going on the Offense with a Strong Defense

Paczosa

Mecsas

2016

Microbiol Mol Biol Rev

1,364

1,345

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SUMMARYKlebsiella pneumoniaecauses a wide range of infections, including pneumonias, urinary tract infections, bacteremias, and liver abscesses. Historically,K. pneumoniaehas caused serious infection primarily in immunocompromised individuals, but the recent emergence and spread of hypervirulent strains have broadened the number of people susceptible to infections to include those who are healthy and immunosufficient. Furthermore,K. pneumoniaestrains have become increasingly resistant to antibiotics, rendering infection by these strains very challenging to treat. The emergence of hypervirulent and antibiotic-resistant strains has driven a number of recent studies. Work has described the worldwide spread of one drug-resistant strain and a host defense axis, interleukin-17 (IL-17), that is important for controlling infection. Four factors, capsule, lipopolysaccharide, fimbriae, and siderophores, have been well studied and are important for virulence in at least one infection model. Several other factors have been less well characterized but are also important in at least one infection model. However, there is a significant amount of heterogeneity inK. pneumoniaestrains, and not every factor plays the same critical role in all virulentKlebsiellastrains. Recent studies have identified additionalK. pneumoniaevirulence factors and led to more insights about factors important for the growth of this pathogen at a variety of tissue sites. Many of these genes encode proteins that function in metabolism and the regulation of transcription. However, much work is left to be done in characterizing these newly discovered factors, understanding how infections differ between healthy and immunocompromised patients, and identifying attractive bacterial or host targets for treating these infections.

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Section: Figmentioning

confidence: 99%

Section: Capsulementioning

confidence: 99%

Klebsiella pneumoniae: Going on the Offense with a Strong Defense

Paczosa

Mecsas

2016

Microbiol Mol Biol Rev

1,364

1,345

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“…wzyAKpK1 encodes a polymerase involved in the assembly of the K1 antigen (7,8). Other important virulence factors in these Klebsiella strains include the rmpA gene, which regulates synthesis of the capsule, and aerobactin, a catecholate siderophore (9)(10)(11)(12). Despite numerous reports confirming the association of this distinctive clinical presentation with K. pneumoniae K1 in Asia, descriptions of K1-associated pyogenic abscesses with ophthalmologic complications originating outside this region are less frequent (5,13).…”

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Klebsiella pneumoniae K1 Liver Abscess and Septic Endophthalmitis in a U.S. Resident

et al. 2013

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Klebsiella pneumoniae K1 is a major agent of hepatic abscess with metastatic disease in East Asia, with sporadic reports originating elsewhere. We report a case of abscess complicated by septic endophthalmitis caused by a wzyAKpK1-positive Klebsiella strain in a U.S. resident, raising concern for global emergence. CASE REPORTA 58-year-old female resident of Bronx, New York, who was originally from the Dominican Republic presented with a chief complaint of 1 day of decreased vision in her right eye and concomitant symptoms, including weakness, myalgia, low-grade fever, and right upper quadrant pain for 1 week. She had a history of uncomplicated choledochal cyst resection and Roux-en-Y hepaticojejunostomy approximately 5 years prior to presentation but no history of ocular disease or prior intraocular surgery. She reported subsequent travel to the Dominican Republic but denied travel to Asia at any point before or after her surgery. On the initial ophthalmic examination, visual acuity was 20/60 in the affected eye. Slit-lamp examination revealed moderate conjunctival injection in the right eye, along with 4ϩ cells and hypopyon in the anterior chamber. The fundus view was hazy because of opacity in the anterior segment, but the retina was flat. She was diagnosed with presumed endogenous endophthalmitis. Her vision in the affected eye worsened over the next 24 h. Because of right upper quadrant tenderness on examination, further imaging was performed, revealing a hepatic abscess (7 by 7 by 7 cm) (Fig. 1). The patient reported no history of diabetes, and the serum glucose was normal. She was treated with intravenous levofloxacin, and the abscess was drained percutaneously. Cultures of liver aspirate, blood, and urine grew K. pneumoniae susceptible to expandedand broad-spectrum cephalosporins, ampicillin-sulbactam, levofloxacin, aminoglycosides, and trimethoprim-sulfamethoxazole. The isolate exhibited a hypermucoviscous phenotype, as exemplified by a positive string test (Fig. 2). On the seventh hospital day, her ophthalmologic exam deteriorated; she was found to have a subretinal abscess in the peripheral temporal retina, and retinal detachment was noted (Fig. 3). A sample of vitreous fluid was obtained, which revealed polymorphonuclear leukocytes on Gram stain but a negative culture, and intravitreal injection of ceftazidime was performed. Over the next several weeks, the vitreous debris cleared, and the retina more clearly assumed the configuration of a bullous rhegmatogenous detachment stemming from a break related to the retinal necrosis at the site of the subretinal abscess. The patient underwent a vitrectomy for retinal detachment 2 months after her initial presentation. The patient's subsequent course was complicated by a relapse of abdominal pain and an increase in size of the liver abscess following a transition to oral therapy. An abdominal CT scan conducted 2 months after the completion of an 8-week antibiotic course demonstrated resolution of her liver abscess.Because of the similarity of this case to rep...

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“…A loss of or decrease in virulence in association with elimination of the K2 capsule is supportive of the capsule's important role in the virulence of the strains (23). We cloned a part of the Klebsiella cps gene cluster (CpSK*), encoding genetic information for Klebsiella K2 capsular polysaccharide synthesis, and rmpA (18) from the chromosome and a large plasmid of K. pneumoniae Chedid, respectively. All of the nonencapsulated mutants of K. pneumoniae tested produced K2 capsular polysaccharide when they were transformed by CpSK* alone, whereas Escherichia coli HB101 required both CpSK* and rmpA for the expression of the thick Klebsiella K2 capsule on the surface (3).…”

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confidence: 99%

Involvement of rcsB in Klebsiella K2 capsule synthesis in Escherichia coli K-12

et al. 1992

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Escherichia coli K-12 harboring a part of the structural genes for the Klebsiella K2 capsular polysaccharide (cpsK*) expresses a large amount of K2 capsular polysaccharide as a thick capsule in the presence of plasmids carrying rmpA and rcsB. We have previously shown that expression of the Klebsiella K2 capsule in E. coli HB101 harboring cpsK* depends on the presence of rmpA, a regulatory gene from a large plasmid of Klebsiella pneumoniae Chedid (O1:K2). E. coli K-12 JM109, however, produces only a small amount of K2 capsular polysaccharide, even in the presence of plasmids carrying rmpA as well as the cpsK* structural genes. Introduction of the rcsB gene, a positive regulator of colanic acid capsule synthesis in E. coli K-12 which was cloned from HB101 on a plasmid, into JM109 cells carrying cpsK* and rmpA, results in the expression of a thick K2 capsule. By Northern (RNA) hybridization analysis, rcsB has been found to enhance transcription of a long strand of mRNA (longer than 14 kb) from cpsK*. These E. coli transformants which produce a thick K2 capsule also express colanic acid production at high levels. Therefore, rcsB can act as a positive regulator of Klebsiella K2 capsule production and two capsular polysaccharides can be expressed in E. coli simultaneously. With a somewhat different strain background, we have found that both of the colanic acid regulators, rcsA and rcsB, contribute to the basal level of Klebsiella K2 capsule expression but that the presence of multicopy rcsB in either an rcsB or an rcsA mutant of E. coli is sufficient to increase the expression of K2 capsular polysaccharide. These results suggest further parallels between the regulation of colanic acid synthesis in E. coli and the regulation of Klebsiella K2 capsule synthesis.

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Positive control of colanic acid synthesis in Escherichia coli by rmpA and rmpB, two virulence‐plasmid genes of Kiebsiella pneumoniae

Cited by 101 publications

References 39 publications

Klebsiella pneumoniae: Going on the Offense with a Strong Defense

Klebsiella pneumoniae: Going on the Offense with a Strong Defense

Klebsiella pneumoniae K1 Liver Abscess and Septic Endophthalmitis in a U.S. Resident

Involvement of rcsB in Klebsiella K2 capsule synthesis in Escherichia coli K-12

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