Production of diamino propionic acid ammonia lyase by a new strain of Salmonella typhimurium PU011.
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BACKGROUND: Seeds of the legume plant Lathyrus sativus, which is grown in arid and semi arid tropical regions, contain Diamino Propionic acid (DAP). DAP is a neurotoxin, which, when consumed, causes a disease called Lathyrism. Lathryrism may manifest as Neurolathyrism or Osteolathyrism, in which the nervous system, and bone formation respectively, are affected. DAP ammonia lyase is produced by a few microorganisms such as Salmonella typhi, Salmonella typhimurium and Pseudomonas, and is capable of detoxifying DAP. RESULTS: S. typhimurium PU011, a non-virulent bacterial strain isolated in our lab, was found to produce DAP ammonia lyase enzyme when grown in minimal medium containing DAP. There was a direct correlation between biomass yield and enzyme activity, until 16 h post inoculation in minimal medium containing DAP. Following ammonium sulphate precipitation and passing through Sephadex G100, CM-Sephadex and DEAE-Sephacel for crude enzyme extract preparation, about 68-fold enzyme purity was obtained. The purified enzyme gave maximum activity at pH 8.0 and was stable up to 45 degrees C. The Km value for the substrate was found to be 0.685 mM, calculated from a Line Weaver Burk plot. CONCLUSION: A new bacterial strain, S.typhimurium PU 011, which is capable of producing DAP ammonia lyase, was isolated. (+info)
Profile of Salmonella enterica subsp. enterica (subspecies I) serotype 4,5,12:i:- strains causing food-borne infections in New York City.
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Strains of newly emerging Salmonella enterica subsp. enterica (subspecies I) serotype 4,5,12:i:- causing food-borne infections, including a large food poisoning outbreak (n = 86) characterized by persistent diarrhea (14% bloody), abdominal pain, fever, and headache, were examined. The organisms were found in the stool samples from the patients. The biochemical profile of the organisms is consistent with that of S. enterica subsp. I serotypes, except for decreased dulcitol (13%) and increased inositol (96%) utilization. Twenty-eight percent of the strains showed resistance to streptomycin, sulfonamides, or tetracycline only; all three antimicrobial agents; or these agents either alone or in combination with ampicillin, trimethoprim, and trimethoprim-sulfamethoxazole. None of the serotype 4,5,12:i:- strains showed resistance or decreased susceptibility to chloramphenicol or ciprofloxacin. On pulsed-field gel electrophoresis (PFGE), the strains showed 11 or 12 resolvable genomic fragments with 18 banding patterns and three PFGE profile (PFP) clusters (i.e., PFP/A, PFP/B, and PFP/C). Seventy-five percent of the isolates fingerprinted were closely related (zero to three band differences; similarity [Dice] coefficient, 86 to 100%); 63% of these were indistinguishable from each other (PFP/A(1)). PFP/A(1) was common to all strains from the outbreak and 11 hospital sources. Strains from six other hospitals shared clusters PFP/B and PFP/C. PFP/C(4), of the environmental isolate, was unrelated to PFP/A and PFP/B. Nine band differences (similarity coefficient, 61%) were noted between PFP/A(1) and PFP/E of the multidrug-resistant S. enterica subsp. enterica serotype Typhimurium definitive type 104 strains. Whether these emerging Salmonella strains represent a monophasic, Dul(-) variant of serotype Typhimurium or S. enterica subsp. enterica serotype Lagos or a distinct serotype of S. enterica subsp. I is not yet known. Some of the phenotypic and genotypic properties of the serotype 4,5,12:i:- strains are described here. (+info)
Molecular subtyping methods for detection of Salmonella enterica serovar Oranienburg outbreaks.
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This study involved 82 Salmonella enterica serovar Oranienburg isolates from patients with gastroenteritis and/or focal infections, healthy carriers, and cuttlefish chips which were epidemiologically linked to a major outbreak that had affected 1,505 people in Japan between 1998 and 1999. We concurrently investigated four different molecular subtyping methods using human salmonellosis-associated Salmonella serovars and their applicability in detection of serovar Oranienburg in an outbreak. Pulsed-field gel electrophoresis (PFGE), enterobacterial repetitive intergenic sequence PCR (ERIC2-PCR), or 16S/23S rRNA ribotyping provided a high degree of interserovar discrimination for most of the serovars, with PFGE being the most discriminatory. For intraserovar typing of serovar Oranienburg, ERIC2-PCR was found to be the most sensitive. Native plasmid profiling, however, revealed nine different subgroups among epidemiologically and genetically related outbreak strains. Using these methods, a link was confirmed between food (cuttlefish chips) and patients in the serovar Oranienburg outbreak. This study underscores the limitations of chromosome-based and plasmid-based typing methods. (+info)
Salmonella in sheep in Iceland.
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In 1995 several outbreaks of food poisoning in humans occurred in Iceland, that were traced to salmonella contamination of singed sheep heads. This prompted us to study the prevalence of salmonella infection in sheep and to trace where and how infection might have occurred. Faecal, intestinal contents and tonsillar samples were collected in the spring and autumn from sheep on 50 farms in the southwestern part of the country, where salmonellosis had been detected and from 5 farms in the northwestern part of the country. All faecal samples from the southwest were negative, whereas samples from 3 farms obtained in the autumn in the northwest were positive. Tonsillae taken in the autumn were positive in sheep from 3 farms in the southwest and 2 in the northwest. Our results show that salmonella infection is rare in Icelandic sheep but healthy carriers my harbour the bacteria in tonsillae. Salmonella was not detected in drainage from slaughterhouses nor in singed sheep heads. (+info)
Genetic diversity of clinical and environmental strains of Salmonella enterica serotype Weltevreden isolated in Malaysia.
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The incidence of food-borne salmonellosis due to Salmonella enterica serotype Weltevreden is reported to be on the increase in Malaysia. The pulsed-field gel electrophoresis (PFGE) subtyping method was used to assess the extent of genetic diversity and clonality of Salmonella serotype Weltevreden strains from humans and the environment. PFGE of XbaI-digested chromosomal DNA from 95 strains of Salmonella serotype Weltevreden gave 39 distinct profiles with a wide range of Dice coefficients (0.27 to 1.00), indicating that PFGE is very discriminative and that multiple clones of Salmonella serotype Weltevreden exist among clinical and environmental isolates. Strains of one dominant pulsotype (pulsotype X1/X2) appeared to be endemic in this region, as they were consistently recovered from humans with salmonellosis between 1996 and 2001 and from raw vegetables. In addition, the sharing of similar PFGE profiles among isolates from humans, vegetables, and beef provides indirect evidence of the possible transmission of salmonellosis from contaminated raw vegetables and meat to humans. Furthermore, the recurrence of PFGE profile X21 among isolates found in samples of vegetables from one wet market indicated the persistence of this clone. The environment in the wet markets may represent a major source of cross-contamination of vegetables with Salmonella serotype Weltevreden. Antibiotic sensitivity tests showed that the clinical isolates of Salmonella serotype Weltevreden remained drug sensitive but that the vegetable isolates were resistant to at least two antibiotics. To the best of our knowledge, this is the first study to compare clinical and environmental isolates of Salmonella serotype Weltevreden in Malaysia. (+info)
Role of electronic data exchange in an international outbreak caused by Salmonella enterica serotype Typhimurium DT204b.
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From July through September 2000, patients in five European countries were infected with a multidrug-resistant strain of Salmonella Typhimurium DT204b. Epidemiologic investigations were facilitated by the transmission of electronic images (Tagged Image Files) of pulsed-field gel electrophoresis profiles. This investigation highlights the importance of standardized protocols for molecular typing in international outbreaks of foodborne disease. (+info)
Outbreak of multidrug-resistant Salmonella newport--United States, January-April 2002.
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During January-April 2002, Salmonella serotype Newport was isolated from 47 persons in five states: New York (34 cases), Michigan (five), Pennsylvania (four), Ohio (two), and Connecticut (two). Antimicrobial-susceptibility testing of three isolates by CDC revealed resistance to amoxicillin/clavulanate, ampicillin, cefoxitin, ceftiofur, cephalothin, chloramphenicol, streptomycin, sulfamethoxazole, and tetracycline. In addition, two of three isolates were resistant to kanamycin; two had decreased susceptibility or resistance to ceftriaxone. To determine the cause of the outbreak, the New York State Department of Health (NYSDOH) and CDC conducted a case-control study. This report summarizes the results of this investigation, which implicated exposure to raw or undercooked ground beef as the vehicle of transmission. The findings also highlight the emergence of multidrug-resistant S. Newport in the United States. These strains exhibit decreased susceptibility or resistance to ceftriaxone, thereby complicating empiric therapy for serious Salmonella infections. Clinicians should be informed of the emergence of these S. Newport strains, and persons should refrain from eating undercooked ground beef and wash their hands after handling raw ground beef. (+info)
An outbreak of typhoid Fever in Florida associated with an imported frozen fruit.
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An outbreak of typhoid fever in Florida involving at least 16 persons during the winter of 1998-99 was investigated using case-control, environmental, and laboratory methods. The genomic profiles of Salmonella serovar Typhi (Salmonella Typhi) isolates from the 15 confirmed case subjects were identical. Consumption of fruit shakes made with frozen mamey, a tropical fruit, was significantly associated with illness (matched odds ratio, 7.6; 95% confidence interval, 1.4-81.4). Laboratory testing showed that the fruit was heavily contaminated with fecal coliforms; no Salmonella Typhi was isolated. The frozen mamey was prepared in plants in Guatemala and Honduras. No further cases occurred after the frozen product was recalled. As our nation's food sources become increasingly globalized, the risk of outbreaks of exotic diseases linked to contaminated imported food will increase. This outbreak highlights the need for new approaches to ensure the safety of our food supply. (+info)