scholarly journals Identification and Characterization of a Gene stp17 Located on the Linear Plasmid pBSSB1 as an Enhanced Gene of Growth and Motility in Salmonella enterica Serovar Typhi

Author(s):  
Haifang Zhang ◽  
Yunxia Zhu ◽  
Xiaofang Xie ◽  
Min Wang ◽  
Hong Du ◽  
...  
2010 ◽  
Vol 38 (17) ◽  
pp. 5893-5908 ◽  
Author(s):  
Suresh V. Chinni ◽  
Carsten A. Raabe ◽  
Robaiza Zakaria ◽  
Gerrit Randau ◽  
Chee Hock Hoe ◽  
...  

2018 ◽  
Vol 2018 ◽  
pp. 1-5 ◽  
Author(s):  
Abdul Azeez Ahamed Riyaaz ◽  
Vindya Perera ◽  
Sabaratnam Sivakumaran ◽  
Nelun de Silva

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.


2008 ◽  
Vol 75 (4) ◽  
pp. 1192-1196 ◽  
Author(s):  
Ashraf A. Khan ◽  
Elizabeth Ponce ◽  
M. S. Nawaz ◽  
Chorng-Ming Cheng ◽  
Junaid A. Khan ◽  
...  

ABSTRACT A total of 210 Salmonella isolates, representing 64 different serovars, were isolated from imported seafood samples, and 55/210 isolates were found to be resistant to at least one antibiotic. Class 1 integrons from three multidrug-resistant Salmonella enterica strains (Salmonella enterica serovars Newport [strain 62], Typhimurium var. Copenhagen [strain 629], and Lansing [strain 803], originating from Hong Kong, the Philippines, and Taiwan, respectively) were characterized. Southern hybridization of plasmids isolated from these strains, using a class 1 integron probe, showed that trimethoprim-sulfamethoxazole and streptomycin resistance genes were located on a megaplasmid in strain 629. Our study indicates that imported seafood could be a reservoir for Salmonella isolates resistant to multiple antibiotics.


2000 ◽  
Vol 182 (4) ◽  
pp. 869-873 ◽  
Author(s):  
Lise Tourneux ◽  
Nadia Bucurenci ◽  
Cosmin Saveanu ◽  
Pierre Alexandre Kaminski ◽  
Madeleine Bouzon ◽  
...  

ABSTRACT We identified in the genome of Salmonella entericaserovar Typhi the gene encoding deoxyribokinase, deoK. Two other genes, vicinal to deoK, were determined to encode the putative deoxyribose transporter (deoP) and a repressor protein (deoQ). This locus, located between theuhpA and ilvN genes, is absent inEscherichia coli. The deoK gene inserted on a plasmid provides a selectable marker in E. coli for growth on deoxyribose-containing medium. Deoxyribokinase is a 306-amino-acid protein which exhibits about 35% identity with ribokinase from serovar Typhi, S. enterica serovar Typhimurium, or E. coli. The catalytic properties of the recombinant deoxyribokinase overproduced in E. colicorrespond to those previously described for the enzyme isolated from serovar Typhimurium. From a sequence comparison between serovar Typhi deoxyribokinase and E. coliribokinase, whose crystal structure was recently solved, we deduced that a key residue differentiating ribose and deoxyribose is Met10, which in ribokinase is replaced by Asn14. Replacement by site-directed mutagenesis of Met10 with Asn decreased theV max of deoxyribokinase by a factor of 2.5 and increased the K m for deoxyribose by a factor of 70, compared to the parent enzyme.


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