Browsing by Author "Gaddad, S M"
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Item Detection, amplification & sequence homology of sodC in clinical isolates of Salmonella sp.(2010-04) Sanjay, M K; Srideshikan, S M; Usha, M S; PhilipRaj, A; Gaddad, S M; Shivannavar, C TBackground & objectives: Periplasmic copper and zinc superoxide dismutase (Cu,Zn-SOD or SodC) is an important component of the antioxidant shield which protects bacteria from the phagocytic oxidative burst. Cu,Zn-SODs protect Gram-negative bacteria against oxygen damage which have also been shown to contribute to the pathogenicity of these bacterial species. We report the presence of SodC in drug resistant Salmonella sp. isolated from patients suffering from enteric fever. Further sodC was amplified, cloned into Escherichia coli and the nucleotide sequence and amino acid sequence homology were compared with the standard strain sSalmonella Typhimurium 14028. Methods: Salmonella enterica serovar Typhi (S. Typhi) and Salmonella enterica serovar Paratyphi (S. Paratyphi) were isolated and identified from blood samples of the patients. The isolates were screened for the presence of Cu, Zn-SOD by PAGE using KCN as inhibitor of Cu,Zn-SOD. The gene (sodC) was amplified by PCR, cloned and sequenced. The nucleotide and amino acid sequences of sodC were compared using CLUSTAL X. Results: SodC was detected in 35 per cent of the Salmonella isolates. Amplification of the genomic DNA of S. Typhi and S. Paratyphi with sodC specific primers resulted in 519 and 515 bp amplicons respectively. Single mutational difference at position 489 was observed between the sodC of S. Typhi and S. Paratyphi while they differed at 6 positions with the sodC of S. Typhimurium 14028. The SodC amino acid sequences of the two isolates were homologous but 3 amino acid difference was observed with that of standard strain S. Typhimurium 14028. Interpretation & conclusions: The presence of SodC in pathogenic bacteria could be a novel candidate as phylogenetic marker.Item Faecal carriage of CTX-M-15-producing Klebsiella pneumoniae in patients with acute gastroenteritis.(2009-05) Muzaheed; Doi, Yohei; Adams-Haduch, J M; Shivannavar, C T; Paterson, D L; Gaddad, S MBackground & objectives: Data on extended-spectrum β-lactamases (ESBLs) produced by Gram-negative bacteria including Klebsiella pneumoniae especially molecular types of ESBL genes from India are limited. The present study was conducted to investigate the carriage and ESBL contents of multidrug-resistant K. pneumoniae recovered from patients with gastroenteritis in a rural village in southern India. Methods: Nine K. pneumoniae isolates obtained from 45 stool samples from patients with gastroenteritis from one rural and two urban sites, in southern India were included in the study. Antibiotic susceptibility testing, PCR analysis and sequencing were conducted to characterize the ESBL genes. Clonal relatedness was assessed by pulsed-fi eld gel electrophoresis (PFGE). Results: All the isolates were found to be resistant to at least one of the third generation cephalosporins tested. All the study isolates were confi rmed to produce ESBLs. PCR and sequencing revealed the responsible gene to be blaCTX-M-15. blaTEM and blaSHV were absent. PFGE indicated that fi ve of seven isolates were absent. PFGE indicated that fi ve of seven isolates from villagers were genetically closely related, and in turn were related to isolates from patients in two urban areas in this region. Interpretation & conclusions: Our fi ndings showed that genetically-related isolates of K. pneumoniae producing CTX-M-15 were present in multiple areas in southern India. Larger studies need to be done in various geographical regions of the country to better defi ne the molecular epidemiology of ESBLproducing K. pneumoniae and its clinical implications.