scholarly journals Virulence Factors of Salmonella Typhi

2021 ◽  
Author(s):  
Noor S.K. Al-Khafaji ◽  
Ali M.K. Al-Bayati ◽  
Hussein O.M. Al-Dahmoshi

S. Typhi is an enteric bacillus which belongs,to the genus Salmonella in the family Enterobacteriacaea and it is a multi–organs pathogen which inhibits the lymphatic tissues of the small intestine, liver, spleen, and blood stream of infected humans.S.Typhi has a mixture of features that make it an efficient pathogen. This species contains an endotoxin that is characteristic of Gram-negative organisms, as well as the virulence-enhancing Vi antigen. Many of the S. Typhi virulence factors are clustered in some areas of the chromosome known as Salmonella pathogenicity islands (SPI), such as adhesion, invasion, and toxin genes. A protein known as invasin that permits non-phagocytic cells is also produced and excreted by the bacterium., Where it is capable of intracellular living. The oxidative burst of leukocytes may also be inhibited, making innate immune reaction ineffective.

2018 ◽  
Vol 5 ◽  
pp. 39-44
Author(s):  
Nandalal Jaishi ◽  
Pramila Pathak ◽  
Pradeep Kumar Shah ◽  
Puspa Raj Dahal

Background: Bacteraemia can develop a broad array of complications that may be difficult to recognize initially and can increase morbidity. The study was thus conducted to identify the causative agents of bacteraemia and to assess antibiogram of the isolates among the patients suspected of blood stream infection visiting Everest hospital, New Baneshwor Kathmandu. Methods: Altogether 400 blood cultures were processed during March, 2015 to August, 2015. Standard Operating Procedures (SOPs) was followed during the processing of the specimens. Antibiotic susceptibility testing of bacterial isolates was done by Kirby Bauer disc diffusion method with Muller-Hinton agar using the guidelines and interpretive criteria of the Clinical and Laboratory Standards Institute (CLSI 2013). Result: The positivity of blood culture was found to be 48 (12%). Gram negative bacterial were found to be more predominant 27(56.2%) than gram positive bacteria 21(43.7%) in causing bacteraemia. The most prevalent isolate was Staphylococcus aureus 15 (31.2%) followed by Salmonella Paratyphi A 10 (20.8%) and Salmonella Typhi 8 (16.6%), E. coli & CoNS 4 (8.3%), Pseudomonas aeruginosa 3 (6.2%) and Klebsiella pneumoniae & Streptococcus pneumoniae 2 (4.1%) respectively. All gram-positive isolates were found to be sensitive to Cefoxitin, Ceftriaxone and Vancomycin followed by Ampicillin (90.42%), Erythromycin (85.71%), Ciprofloxacin (83.33%), Doxycycline (75%) and Cephalexin (70.58%) whereas gram negative isolates were sensitive to Ceftriaxone followed by Chloramphenicol (92%), Gentamicin (88.8%), Cefixime (85.71%), Ofloxacin (83.3%) and Amoxycillin and Ciprofloxacin (71.3%) Conclusion: The isolation of etiological agents of blood stream infection should be assessed by proper microbiological analysis and it would be helpful for controlling of the outbreaks of resistance strains through effective empirical therapy.


2004 ◽  
Vol 48 (7) ◽  
pp. 2771-2777 ◽  
Author(s):  
Laurel S. Almer ◽  
Jennifer B. Hoffrage ◽  
Erika L. Keller ◽  
Robert K. Flamm ◽  
Virginia D. Shortridge

ABSTRACT In vitro activities of ABT-492, ciprofloxacin, levofloxacin, trovafloxacin, moxifloxacin, gatifloxacin, and gemifloxacin were compared. ABT-492 was more potent against quinolone-susceptible and -resistant gram-positive organisms, had activity similar to that of ciprofloxacin against certain members of the family Enterobacteriaceae, and had comparable activity against quinolone-susceptible, nonfermentative, gram-negative organisms. Bactericidal activity of ABT-492 was also evaluated.


2020 ◽  
Vol 9 (4) ◽  
pp. e34-e34
Author(s):  
Babak Hadian ◽  
Azita Zafarmohtashami ◽  
Mahdi Razani

Introduction: Proper care of vascular access in hemodialysis patients is important. Catheter-related bloodstream infection (CRBSI), is a life-threatening complication of hemodialysis. Objectives: Sufficient data about microorganisms and their susceptibility to antibiotics in hemodialysis patients is necessary for handling of CRBSI; therefore, this study performed for better management of patients. Patients and Methods: All hemodialysis patients from March 2015 to March 2018 who had cultures of catheter and blood samples were studied. Clinical records of 122 patients were reviewed for variables such as catheter and blood culture microorganism types, antibiotic resistance, age, gender, site, comorbidities, and various clinical signs. Results: Eighty-four cases of catheter cultures were positive for bacteria. Staphylococcus epidermidis was the most common organism (36%) since Staphylococcus aureus was the second one (28%). In some cases, multidrug resistant organisms such as Enterobacter baumannii or methicillin-resistant Staphylococcus aureus (MRSA) organisms were grown. Twenty-one percent of S. aureus organisms were MRSA. No significant association between important diagnostic data (fever, chills or WBC count) and bacteremia were shown. Gender of patients had a significant statistical association with CRBSI. Conclusion: Given the necessity of proper management, physicians must empirically initiate antibiotic therapy as soon as possible, until receiving definite culture results, in hemodialysis patients suspected of bacteremia. In our study, both gram-positive and gram-negative organisms were common. Hence, when initial empirical treatment is indicated, the coverage of both gram positive and gram negative organisms must be considered. Vancomycin or other antibiotics that are effective on MRSA must be included in empirical treatment.


2016 ◽  
Author(s):  
Allison Mah ◽  
Inna Sekirov ◽  
Theodore S Steiner

This review describes infections caused by Escherichia coli and related members of the family Enterobacteriaceae, excluding other genera that principally cause enteric infections. Infections caused by Salmonella, Shigella, and Yersinia are described in the review “Gastrointestinal Tract Infections," found elsewhere in this publication. The purpose of this review is to examine the specific epidemiology, clinical manifestations, and treatment of individual members of the Enterobacteriaceae. The emerging concern of antimicrobial resistance amongst enteric gram-negative organisms and the approach to treatment in the setting of infection with these resistant organisms are discussed in the review “Antimicrobial Resistance in Enteric Gram-Negative Organisms,” found elsewhere in this publication. Figures illustrate the mechanisms of antimicrobial resistance in Enterobacteriaceae. A table lists the clinical, epidemiologic, pathogenetic, and therapeutic aspects of infection with various pathotypes of Escherichia coli. This review contains 6 highly rendered figures, 1 table, and 79 references.


Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 4937-4937
Author(s):  
Mohamed A. Yassin ◽  
Nayel a Altarawneh ◽  
Joanne N Daghfal ◽  
Rami T Kamzoul ◽  
Hanadi Rafii El-Ayoubi

Abstract Abstract 4937 Background: Central-line access is an important part of healthcare practice especially for patients with hematological malignancies; however,central line-associated blood stream infection (CLABSIs) are important and deadly Health- care–associated infections (HAIs) and they are considered as a major problem that causes significant morbidity and mortality, and excess length of stay and cost. The risk of infection depends on, the site of insertion, the type of device, the underlying co morbidity and the appropriate prevention measures taken during insertion. Management of central line-associated bloodstream infections involves deciding on the type and duration of systemic antimicrobial therapy and catheter removal, antibiotic lock therapy. Systemic antimicrobial use is essential but, although generally effective in controlling sepsis, it often fails to sterilize the line, increasing the incidence of complications or recurrence. The decision regarding whether the catheter should be removed or retained is therefore crucial. One of the major factors to be considered is the type of organism involved in the line-related infection. Aim: to evaluate the central Line-associated blood stream infections in patients with hematological malignancies in Al-Amal Hospital, (inpatient wards, outpatient day care unit) and among patients transferred to intensive-care units. Patients and Methods: we evaluated central Line-associated blood stream infections in patients with hematological malignancies admitted to Al-Amal Hospital in Qatar between February 2007-December 2010. Strict protocol for febrile neutropenia is followed with proper timely intervention. Systematic review for all blood stream infections were done by nursing infection control practitioners, hematologists, microbiologists following the definitions of CDC-NHSN. Results: 39 events were evaluated, 25 (64%) events in patients with AML, 10 (26%) events with ALL, 2 (5%) events with CLL, 1 (2.5%) event with CML and 1 (2.5%) event with NHL. Males were 25 and females were 14, with male to female ratio 1.8:1. The age range from 19 to 69 year with mean age group of 42 year. The most common infections were Gram negative organisms (27events), and among the gram negative organisms pseudomonas was the commonest infection (7 events), with 4 of them died, MDR reported in 6 events among the gram negative infections. Fungal infections were 9 events (6 Candida and 3 Aspergillus) with one death due to Candida tropicalis, the least common infections were Gram positive organisms, 3 events were recorded with one mortality due to staph. hemoliticus. Overall mortality was 9 out of 39 (23%). Conclusion: most of the infections occurred in non-tunneled catheters, and then tunneled catheters, rarely with port-A-Catheter. Based on the isolates the mortality was higher among patients with gram negative which is expected in such category of patients, and despite high number of fungal infections the mortality rate was low in affected patients (due to timely intervention with removal of line and proper use of anti-fungal ). Continued success in CLABSI prevention will require increased adherence to current CLABSI prevention recommendations, development and implementation of additional prevention strategies, and the ongoing collection and analysis of data, including specific microbiological informations. Disclosures: No relevant conflicts of interest to declare.


2014 ◽  
Vol 99 (Suppl 1) ◽  
pp. A161-A162
Author(s):  
D. Keene ◽  
C. Hughes-Day ◽  
L. Stephens ◽  
S. Almond ◽  
D. Sanyal ◽  
...  

2008 ◽  
Vol 52 (5) ◽  
pp. 1653-1662 ◽  
Author(s):  
Laura Lawrence ◽  
Paul Danese ◽  
Joe DeVito ◽  
Francois Franceschi ◽  
Joyce Sutcliffe

ABSTRACT Rx-01_423 and Rx-01_667 are two members of the family of oxazolidinones that were designed using a combination of computational and medicinal chemistry and conventional biological techniques. The compounds have a two- to eightfold-improved potency over linezolid against serious gram-positive pathogens, including methicillin-resistant Staphylococcus aureus (MRSA), multidrug-resistant streptococci, and vancomycin-resistant enterococci. This enhanced potency extends to the coverage of linezolid-resistant gram-positive microbes, especially multidrug-resistant enterococci and pneumococci. Compounds from this series expand the spectrum compared with linezolid to include fastidious gram-negative organisms like Haemophilus influenzae and Moraxella catarrhalis. Like linezolid, the Rx-01 compounds are bacteriostatic against MRSA and enterococci but are generally bactericidal against S. pneumoniae and H. influenzae.


1964 ◽  
Vol 119 (1) ◽  
pp. 41-51 ◽  
Author(s):  
Etsuko Osawa ◽  
Louis H. Muschel

Paracolobactrum ballerup, an organism considered completely insusceptible to the bactericidal action of the antibody-complement system, became extremely sensitive to immune serum and even to normal serum, in conjunction with complement, when cultivated at temperatures above 37°C. This conversion to serum sensitivity was associated with the loss of the organism's Vi antigen and its tendency to assume a rough state. It did not result in a genetic change in the organism, however, since reincubation of serum-sensitive P. ballerup at 37°C resulted in a restoration of its resistance. The loss of serum resistance as a result of cultivation temperatures above 37°C may be of significance as an example of the enhancement of host defense mechanisms induced by fever. Special conditions of testing indicated that P. ballerup cultured at 37°C and S. paratyphosa C, organisms considered insusceptible to serum bactericidal action, were not entirely refractory to serum. These conditions included simply a relatively low ratio of the number of test organisms to serum volume and an extended incubation period of the organisms with serum bactericidal substances, or even without these substances, prior to the initiation of bactericidal action. It is likely, therefore, that an absolute distinction between serum-sensitive and serum-resistant Gram-negative organisms does not exist, but rather that there is a very broad distribution of serum sensitivity among these organisms.


2017 ◽  
Vol 4 (2) ◽  
pp. 365 ◽  
Author(s):  
Varsha Suresh Ahirrao ◽  
Anupama Mauskar ◽  
Ravi T.

Background: S. aureus, coagulase negative staphylococci, enterococci, a variety of gram-negative bacilli, and Candida spp. are responsible for the vast majority of infections. Coagulase negative staphylococcal infections have increased dramatically in past 2 decades, almost entirely because of increase in the frequency of blood stream infections caused by these organisms.Methods: Appropriate microbiological samples were taken from the site of infection from all the patients included in the study. Whenever necessary, required serological examinations are sent.Results: Of 30 episodes of nosocomial infections from which any pathogen was isolated, three episodes were polymicrobial. Gram-negative organisms were more frequently (76.67%) isolated than gram-positive organisms (20%), and fungi (3.33%).Conclusions: Almost all gram-negative bacteria showed 100% sensitivity to Imipenem. Pseudomonas isolates showed sensitivity of 100% to Imipenem, 83.33% to Piperacillin+Tazobactum. Klebsiella showed sensitivity of 83.33% to Ciprofloxacin and Amikacin.


Sign in / Sign up

Export Citation Format

Share Document