scholarly journals The Salmonella enterica Serovar Typhi Type IVB Self-Association Pili Are Detached from the Bacterial Cell by the PilV Minor Pilus Proteins

2006 ◽  
Vol 74 (9) ◽  
pp. 5414-5418 ◽  
Author(s):  
Connie K. P. Tam ◽  
Christina Morris ◽  
Jim Hackett
Keyword(s):  
Typhoid Fever ◽  
Bacterial Cell ◽  
Salmonella Enterica ◽  
Enteric Fever ◽  
Dna Supercoiling ◽  
Bacterial Membrane ◽  
Salmonella Enterica Serovar Typhi ◽  
Protein Molecules ◽  
Dna Fragment ◽  
Self Association

ABSTRACT Salmonella enterica serovar Typhi and some strains (Vi+) of serovar Dublin use type IVB pili to facilitate bacterial self-association, but only when the PilV proteins (potential minor pilus proteins) are not synthesized. Pilus-mediated self-association may be important in the pathogenesis of enteric fever. We have shown previously that the extent of DNA supercoiling controls the rate of Rci-catalyzed inversion of a DNA fragment which includes the C-terminal portions of the PilV proteins. This inversion therefore controls PilV synthesis as a high inversion rate prohibits transcription of pilV-encoding DNA. Here, we describe the manner in which PilV protein expression inhibits bacterial self-association and present data which suggest that incorporation of one or a few PilV protein molecules into a growing pilus, comprised of PilS subunits, causes the pilus to detach at the bacterial membrane. The bacteria are then unable to self-associate. We suggest that this phenomenon may be relevant to the pathogenesis of typhoid fever.

scholarly journals Salmonella enterica Serovar Paratyphi C Carries an Inactive Shufflon

2004 ◽  
Vol 72 (1) ◽  
pp. 22-28 ◽  
Author(s):  
Connie K. P. Tam ◽  
Jim Hackett ◽  
Christina Morris
Keyword(s):  
Typhoid Fever ◽  
Base Pair ◽  
Salmonella Enterica ◽  
Enteric Fever ◽  
Terminal Region ◽  
Inverted Repeats ◽  
Single Base ◽  
Single Base Pair ◽  
Self Association ◽  
Base Pair Insertion

ABSTRACT Salmonella enterica serovar Typhi uses type IVB pili to facilitate bacterial self-association, but only when the PilV proteins (potential minor pilus proteins) are not synthesized. This pilus-mediated event may be important in typhoid fever pathogenesis. We initially show that S. enterica serovar Paratyphi C strains harbor a pil operon very similar to that of serovar Typhi. An important difference, however, is located in the shufflon which concludes the pil operon. In serovar Typhi, the Rci recombinase acts upon two 19-bp inverted repeats to invert the terminal region of the pilV gene, thereby disrupting PilV synthesis and permitting bacterial self-association. In serovar Paratyphi C, however, the shufflon is essentially inactive because each of the Rci 19-bp substrates has acquired a single base pair insertion. A PilV protein is thus synthesized whenever the pil operon is active, and bacterial self-association therefore does not occur in serovar Paratyphi C. The data thus suggest that serovar Typhi bacterial self-association using type IVB pili may be important in the pathogenesis of epidemic enteric fever.

scholarly journals Highly Resistant Salmonella enterica Serovar Typhi with a NovelgyrAMutation Raises Questions about the Long-Term Efficacy of Older Fluoroquinolones for Treating Typhoid Fever

2012 ◽  
Vol 56 (5) ◽  
pp. 2761-2762 ◽  
Author(s):  
Kanika Deshpande Koirala ◽  
Duy Pham Thanh ◽  
Sudeep Dhoj Thapa ◽  
Amit Arjyal ◽  
Abhilasha Karkey ◽  
...  
Keyword(s):  
Multidrug Resistance ◽  
Typhoid Fever ◽  
Treatment Failure ◽  
Salmonella Enterica ◽  
Systemic Infection ◽  
Resistant Isolate ◽  
Content Type ◽  
Salmonella Enterica Serovar Typhi ◽  
Term Efficacy

ABSTRACTAs a consequence of multidrug resistance, clinicians are highly dependent on fluoroquinolones for treating the serious systemic infection typhoid fever. While reduced susceptibility to fluoroquinolones, which lessens clinical efficacy, is becoming ubiquitous, comprehensive resistance is exceptional. Here we report ofloxacin treatment failure in typhoidal patient infected with a novel, highly fluoroquinolone-resistant isolate ofSalmonella entericaserovar Typhi. The isolation of this organism has serious implications for the long-term efficacy of ciprofloxacin and ofloxacin for typhoid treatment.

scholarly journals Typhoid Fever due to Extended Spectrum β-Lactamase-Producing Salmonella enterica Serovar Typhi: A Case Report and Literature Review

2018 ◽  
Vol 2018 ◽  
pp. 1-5 ◽  
Author(s):  
Abdul Azeez Ahamed Riyaaz ◽  
Vindya Perera ◽  
Sabaratnam Sivakumaran ◽  
Nelun de Silva
Keyword(s):  
Case Report ◽  
Sri Lanka ◽  
Typhoid Fever ◽  
Salmonella Enterica ◽  
Salmonella Enterica Serovar Typhi ◽  
Extended Spectrum ◽  
Cephalosporin Resistance ◽  
Resistant Strains ◽  
Derivatives Of

Emergence of cephalosporin-resistant strains of Salmonella enterica serovar Typhi is a cause of concern in the management of enteric fever. Cephalosporin resistance in Salmonella species is mainly due to the production of extended-spectrum β-lactamases (ESBLs). The majority of ESBLs in Salmonella enterica serovar Typhi are derivatives of the TEM, SHV, and CTX-M β-lactamase families. Of these, CTX-M appears to be predominant. This paper discusses the detection and molecular characterization of an ESBL-producing Salmonella enterica serovar Typhi strain isolated from a patient who was admitted to a private hospital in Sri Lanka. The three main types of β-lactamases such as TEM, SHV, and CTX-M were identified in this isolate. This case report from Sri Lanka contributes to the knowledge of the increasingly reported cases of typhoid fever due to Salmonella enterica serovar Typhi resistant to β-lactamase by ESBL production.

scholarly journals Comparision of Antibiotic Susceptility of Levofloxacin with Other Commonly Tested Antibiotics Against Salmonella Enterica Serovar (Typhi And Paratyphi A)

2014 ◽  
Vol 3 (1) ◽  
pp. 19-21
Author(s):  
A Chhetri ◽  
A Manandhar ◽  
Y Shah ◽  
RC Simkhada ◽  
R Paudyal ◽  
...  
Keyword(s):  
Nalidixic Acid ◽  
Salmonella Enterica ◽  
Antibiotic Susceptibility ◽  
Enteric Fever ◽  
Clinical Laboratory ◽  
Acid Resistance ◽  
Fluoroquinolone Resistance ◽  
Diffusion Method ◽  
Salmonella Enterica Serovar Typhi ◽  
Antibiotic Susceptibility Test

Background: Increasing antibiotic resistance of bacteria is a global problem. Fluoroquinolones are recommended as first line therapy for children and adults infected with Salmonella enterica serovar Typhi and Paratyphi A. The purpose of this study was to compare the antibiotic susceptibility pattern of different classes of antibiotics with levofloxacin from blood samples of suspected enteric fever patients visiting Birhospital, Kathmandu. Methods: Antibiotic susceptibility test was performed by Kirby-Bauerdisc diffusion method as per Clinical Laboratory Standards Institute guideline. Results: Among 50 isolates of Salmonella enterica, 39 (78%) were S.Typhi and 11 (22%) were S. Paratyphi A. All the isolates were tested against antibiotics, and all isolates were found sensitive to chloramphenicol and ceftriaxone whereas 3 isolates of S. Typhi were resistant to ciprofloxacin and 1 was resistant to levofloxacin. Fluoroquinolone resistant S. ParatyphiA was not observed. Among the 10 (20%) multi drug resistant isolates, only 1 isolate was resistant to levofloxacin which was S. Typhi. Both S.Typhi (96.7%) and S. Paratyphi A (89.4%) were resistant to Nalidixic acid. Conclusion: High level of nalidixic acid resistance and even some fluoroquinolone resistance showed that the treatment of the enteric fever cannot be relied on the fluoroquinolones. Nepal Journal of Medical Sciences | Volume 03 | Number 01 | January-June 2014 | Page 19-21 DOI: http://dx.doi.org/10.3126/njms.v3i1.10344

scholarly journals Ciprofloxacin treatment failure in a case of typhoid fever caused by Salmonella enterica serotype Paratyphi A with reduced susceptibility to ciprofloxacin

2007 ◽  
Vol 56 (2) ◽  
pp. 277-279 ◽  
Author(s):  
Tzonyo Dimitrov ◽  
Edet E. Udo ◽  
Osama Albaksami ◽  
Abdul A. Kilani ◽  
El-Din M. R. Shehab
Keyword(s):  
Typhoid Fever ◽  
Treatment Failure ◽  
Salmonella Enterica ◽  
Enteric Fever ◽  
Susceptibility Testing ◽  
Laboratory Methods ◽  
New Guidelines ◽  
Oral Ciprofloxacin

This report describes a case of ciprofloxacin treatment failure in a patient with enteric fever caused by Salmonella enterica serotype Paratyphi A. The organism was isolated from a blood culture from a patient who was treated with oral ciprofloxacin (500 mg every 12 h) for 13 days. The organism showed reduced susceptibility to ciprofloxacin (MIC 0.75 μg ml−1) and was resistant to nalidixic acid. The patient was then placed on intravenous ceftriaxone (1 g every 12 h) and responded within 3 days. The patient was discharged after 9 days on ceftriaxone with no relapse on follow-up. This case adds to the increasing incidence of treatment failures with ciprofloxacin in typhoid fever caused by typhoid salmonellae with reduced susceptibility to ciprofloxacin. It also highlights the inadequacy of current laboratory methods for fluoroquinolone susceptibility testing in adequately predicting in vivo activity of ciprofloxacin against typhoid salmonellae and supports calls for new guidelines for fluoroquinolone susceptibility testing of these organisms.

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