Rapid detection of Salmonella enterica serovar Typhi from Humans

ArticleinJournal of Pure and Applied Microbiology 04(02):837-841 · May 2010with38 Reads
Abstract
Present study was carried out to investigate Salmonella enterica serovar Typhi associated with Typhoid fever in humans. A total of six blood samples were collected from six patients (4 males and 2 females) and processed for the isolation and identification of the causative agents and their virulence determinants. Microbial investigation revealed the causative agents Salmonella enterica Serovar Typhi in all the six clinical cases. In polymerase chain reaction (PCR) assay, all the six isolates were found positive for the Invasion gene (invA; 244bp fragment), Tyvelose epimerase gene (tyv; 615bp fragment), phage-1 flagellin gene for d-antigen (fliC-d; 750bp fragment) and Vi antigen genes (viaB; 439bp fragment). This study confirms the association of virulent strains of Salmonella enterica Typhi in occurrence of the Typhoid fever in humans. Present study suggested that PCR can be a useful, high throughput diagnostic tool for the rapid detection of Salmonella enterica Serovar Typhi.
    • "In the present study, 14 isolates of S. typhi were obtained from regional hospital Solan, HP from individuals below 30 years of age in which attack rate is significantly higher. Similar to the present study, the detection of typhoid bacilli from the patient of less than 30 years of age was also reported from Tamil Nadu in high frequency [1]. In PCR analysis, dhfr a7 gene was targeted for the Trimethoprim resistance based identification of S. enterica serovar typhi which revealed the detection of several isolates originated from typhoidal humans. "
    [Show abstract] [Hide abstract] ABSTRACT: Typhoid is a major public health problem in tropical and subtropical countries including India. Salmonella typhi, the causative agent of typhoid fever, is a gram-negative, motile, rod shaped, facultative anaerobe. It is solely a human pathogen and there is no animal reservoir. Antibiotic therapy is the mainstay for the treatment of typhoid fever and the complications associated with it. Nowadays, emerging multidrug resistance among Salmonella typhi strains has become a major public health problem. Present research work was carried out for the identification and molecular characterization of Trimethoprim resistant Salmonella enterica serovar typhi strains from individuals suffering with typhoid fever by means of various techniques i.e.; biochemicals, phenotypical and drug resistant gene specific polymerase chain reaction (PCR). A total of 14 blood specimen of infected patients were collected from Solan district of Himachal Pradesh with varying age groups and were processed via broth enrichment methods for primary isolation and identification of typhoid bacilli. Microbiological and biochemical investigations revealed the presence of S. typhi in all 14 specimens. The antibiotic susceptibility assay was carried out for 11 antimicrobial to study the MDR pattern of the identified bacilli. It was observed that 14/14 S. typhi strains were 100% resistance to Trimethoprim, Co-trimoxazole, Sulfanilamide, Penicillin, Ampicillin, Oxacillin, Tetracycline and Erythromycin, and 70-100% susceptible to Levofloxacin, Amikacin and Amoxicillin. The PCR analysis of these MDR strains showed the presence of dhfr a7 (365 bp) gene in only 10/14 isolates. This study confirmed that Trimethoprim resistance in these strains were due to the presence of dhfr a7 gene and also that PCR based diagnosis could be very useful for the rapid detection of drug resistant S. typhi strains. Present study emphasize that Trimethoprim drug is no longer useful for the treatment of typhoid fever as its MIC optimization was very high (750μg/ml). This study may further help the researchers in selecting the appropriate therapeutic approaches targeting Trimethoprim resistant Salmonella typhi strains.
    Full-text · Article · Jan 2016
    • "The result of antibiotic susceptibility test revealed that isolates of S. Typhi were 100 % resistant to ampicillin, 81.25 % to cefuroxime and 68.75 % resistant to penicillin- G and cephalothin respectively. The ampicillin resistant S. Typhi isolates from the typhoidial patients from Tamil Nadu, India were reported earlier (Ganeshkumar et al., 2010). The present result clearly indicating the tendency of the S. Typhi isolates to become resistance towards multiple drugs. "
    Full-text · Dataset · Mar 2013
    • "A:Ampillicin, C:Chloramphenicol, Cb:Carbenicillin, Cd:Clindamycin, Ch:Cephalothin, Cu:Cefuroxime, G:Gentamycin, K:Kanamycin, Na:Nalidixic acid, Nf:Nitrofurantoin, P:Penicillin G, T:Tetracycline Typhi isolates from the typhoidial patients from Tamil Nadu, India were reported earlier (Ganeshkumar et al., 2010). "
    [Show abstract] [Hide abstract] ABSTRACT: Aims: Salmonella enterica serovar Typhi is the major causative agent for typhoidial fever around the globe among human population reported till date. Present research work was carried out for detection and molecular characterisation of Salmonella enterica serovar Typhi isolated from humans with Typhoidial fever by biochemical, phenotypical and virulence gene based polymerase chain reaction (PCR) techniques. The isolated strains were also investigated for antibiotic susceptibility patterns as a control measure. Methodology and Results: A total of 16 clinical samples were collected from the same numbers of patients (7 males and 9 females) from Coimbatore, Erode and Salem districts of Tamil Nadu and were processed via broth enrichment methods for isolation and identification of the causative agent S. enterica serovar Typhi. Microbiological and biochemical investigations revealed the presence of S. Typhi from 16 samples. The biotyping of the isolates showed that all the isolates belonged to biotype IV. The PCR analysis confirmed the presence of invA (Invasion gene, 244bp), tyv (Tyvelose epimerase gene, 615 bp), fliC-d (Phage-1 flagellin gene for d-antigen, 750 bp) and viaB (Vi antigen gene, 439bp) in all 16 clinical samples. The antibiotic susceptibility test that was carried out among the isolates against 12 antimicrobial agents, showed 100 % resistance to only ampicillin and 100 % sensitivity to carbenicillin, chloramphenicol, clindamycin, gentamycin, kanamycin and tetracycline. Conclusion, significance and impact of study: This study confirmed the association of virulent strains of S. enterica serovar Typhi from Typhoidial fever among human population and suggested that PCR based diagnostic could be very useful for the rapid detection of S. Typhi isolates. Present study emphasized the use of antibiotic like chloramphenicol or in combination with other antibiotics for the effective control of S. Typhi.
    Full-text · Article · Apr 2012
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