Semisolid media for isolation of Salmonella spp. from coastal waters

The use of two semisolid media (semisolid Rappaport and semisolid Rappaport-Vassiliadis) for the isolation of Salmonella spp. from coastal waters was compared with the use of conventional media. Two hundred and fifty six samples were studied; Salmonella spp. were detected in 83. The semisolid media were the most sensitive, detecting 73 samples instead of the 53 detected by the conventional media (P less than 0.001). The rate of isolation of Salmonella spp. showed an increase of 56.6% when the semisolid media were added to the conventional media, it being possible to detect 54.2% of the total organisms 1 day earlier.     

Modification of kanamycin-esculin-azide agar to improve selectivity in the enumeration of fecal streptococci from water samples.

Kanamycin-esculin-azide agar was modified by increasing the concentration of sodium azide to 0.4 g liter-1 and replacing kanamycin sulfate with 5 mg of oxolinic acid liter-1. The modification, named oxolinic acid-esculin-azide (OAA) agar, was compared with Slanetz-Bartley and KF agars by using drinking water and seawater samples. The OAA agar showed higher specificity, selectivity, and recovery efficiencies than those obtained by using the other media. In addition, no confirmation of typical colonies was needed when OAA agar was used, which significantly shortens the time of sample processing and increases the accuracy of the method.     

Anisakis simplex: dangerous--dead and alive?

The risk of infection with Anisakis simplex and related parasites of fish has been recognized for some time, but it is now emerging that ingestion of material from dead parasites in food is also potentially dangerous. The resulting allergic reactions range from rapid onset and potentially lethal anaphylactic reactions to chronic, debilitating conditions. This review discusses the problems and clinical implications associated with A. simplex, other related conditions, and the way in which disease manifestations vary from person to person.     

Suitability of PCR Fingerprinting, Infrequent-Restriction-Site PCR, and Pulsed-Field Gel Electrophoresis, Combined with Computerized Gel Analysis, in Library Typing of Salmonella enterica Serovar Enteritidis

Strains of Salmonella enterica (n = 212) of different serovars and phage types were used to establish a library typing computerized system for serovar Enteritidis on the basis of PCR fingerprinting, infrequent-restriction-site PCR (IRS-PCR), or pulsed-field gel electrophoresis (PFGE). The rate of PCR fingerprinting interassay and intercenter reproducibility was low and was only increased when DNA samples were extracted at the same time and amplified with the same reaction mixtures. Reproducibility of IRS-PCR technique reached 100%, but discrimination was low (D = 0.52). The PFGE procedure showed an intercenter reproducibility value of 93.3%. The high reproducibility of PFGE combined with the previously determined high discrimination directed its use for library typing. The use of PFGE with enzymes XbaI, BlnI, and SpeI for library typing of serovar Enteritidis was assessed with GelCompar 4.0 software. Three computer libraries of PFGE DNA profiles were constructed, and their ability to recognize new DNA profiles was analyzed. The results obtained pointed out that the combination of PFGE with computerized analysis could be suitable in long-term epidemiological comparison and surveillance of Salmonella serovar Enteritidis, specially if the prevalence of genetic events that could be responsible for changes in PFGE profiles in this serovar was low.     

Semisolid media for isolation of Salmonella spp. from coastal waters.

The use of two semisolid media (semisolid Rappaport and semisolid Rappaport-Vassiliadis) for the isolation of Salmonella spp. from coastal waters was compared with the use of conventional media. Two hundred and fifty six samples were studied; Salmonella spp. were detected in 83. The semisolid media were the most sensitive, detecting 73 samples instead of the 53 detected by the conventional media (P less than 0.001). The rate of isolation of Salmonella spp. showed an increase of 56.6% when the semisolid media were added to the conventional media, it being possible to detect 54.2% of the total organisms 1 day earlier.     

Suitability of PCR fingerprinting, infrequent-restriction-site PCR, and pulsed-field gel electrophoresis, combined with computerized gel analysis, in library typing of Salmonella enterica serovar enteritidis

Strains of Salmonella enterica (n = 212) of different serovars and phage types were used to establish a library typing computerized system for serovar Enteritidis on the basis of PCR fingerprinting, infrequent-restriction-site PCR (IRS-PCR), or pulsed-field gel electrophoresis (PFGE). The rate of PCR fingerprinting interassay and intercenter reproducibility was low and was only increased when DNA samples were extracted at the same time and amplified with the same reaction mixtures. Reproducibility of IRS-PCR technique reached 100%, but discrimination was low (D = 0.52). The PFGE procedure showed an intercenter reproducibility value of 93.3%. The high reproducibility of PFGE combined with the previously determined high discrimination directed its use for library typing. The use of PFGE with enzymes XbaI, BlnI, and SpeI for library typing of serovar Enteritidis was assessed with GelCompar 4.0 software. Three computer libraries of PFGE DNA profiles were constructed, and their ability to recognize new DNA profiles was analyzed. The results obtained pointed out that the combination of PFGE with computerized analysis could be suitable in long-term epidemiological comparison and surveillance of Salmonella serovar Enteritidis, specially if the prevalence of genetic events that could be responsible for changes in PFGE profiles in this serovar was low.     

Typing of Salmonella enteritidis of different phage types of PCR fingerprinting

Fifty-nine isolates of Salmonella spp. were typed by PCR fingerprinting using three single primers: ERIC2, M13 and OPS-19. First, their discrimination power in a group of nine different serotypes were studied and considerable differences in the band patterns were obtained. Further, a panel of 51 isolates of Salmonella enteritidis with eight different phage types were analysed with the three primers. The discriminating power increased by combining the patterns of the three primers, and in this case it was possible to distinguish between some phage types of Salm. enteritidis , but not all of them were differentiated.