Since 1998, episodes of mass mortality have occurred in populations of common carp Cyprinus carpio carpio in Israel and in populations of koi Cyprinus carpio koi in Israel and the USA. A herpesvirus isolated from infected fish has been shown in experimental studies to induce disease and mortality similar to those observed in outbreaks at infected farms. Initial characteristics of the virus show that it is clearly different from Herpesvirus cyprini (CHV), the most commonly known herpesvirus from cyprinid fish. The koi herpesvirus (KHV) has 31 virion polypeptides. Twelve of the virion polypeptides of KHV have similar molecular weights to those of CHV and 10 are similar to those of channel catfish virus (CCV). Both virion polypeptide and restriction fragment length polymorphism analyses of genomic DNA showed that the first KHV isolates from Israel and the USA were identical. In contrast, the genomic DNA restriction fragments clearly distinguish KHV from CHV and CCV. A polymerase chain reaction (PCR) assay to detect the virus in koi tissues was developed with sequences obtained from 1 restriction fragment of KHV DNA. The PCR assay effectively detected a 484 base pair sequence from KHV but did not amplify genomic DNA from either CHV or CCV. The PCR assay detected as little as 1 pg of KHV DNA mixed with 100 ng of host DNA. Viral sequences were amplified from koi obtained from field collections and from koi that were experimentally exposed to 10 2 TCID 50 ml -1 of KHV via the waterborne route. All KHV exposed fish dying of infection between 8 and 10 d post exposure or surviving to 14 d post exposure were found to be positive by PCR, while unexposed control koi were all negative. The assay also showed the presence of KHV DNA in tissues of koi obtained from farms in Israel. The PCR assay should assist virus isolation procedures and histologic and electron microscopic analyses now commonly used to detect KHV infection. Current studies are examining the possibility of using the PCR to detect KHV DNA in live fish and the relative sensitivity and specificity of the KHV PCR assay compared with other diagnostic tests.

The use of active surveillance and contact precautions, as part of a multifactorial intervention, may be an effective strategy to decrease rates of nosocomial transmission of carbapenem-resistant K. pneumoniae colonization or infection.

Lactococcus garvieae (junior synonym Enterococcus seriolicida) is an emerging zoonotic agent isolated from economically important fish (rainbow trout and yellowtail), from cattle, and from humans. Clindamycin susceptibility is the only phenotypic test which can differentiate L. garvieae fromLactococcus lactis, another emerging agent in humans. A PCR assay for the identification of L. garvieae was developed and resulted in an amplified fragment of 1,100 bp in size. The PCR assay was shown to be specific to L. garvieae. The PCR assay was positive for all the L. garvieae strains tested, which originated from three different continents (Asia, Australia, and Europe). The PCR assay was negative for the phenotypically similarL. lactis and for all the other fish pathogens tested, including Streptococcus iniae and Aeromonas salmonicida. The PCR assay was applied to plasma obtained from diseased animals and was found sensitive enough to detect bacteria from 1 μl of plasma. The PCR assay that was developed is the only practical test besides the clindamycin test which can specifically identify the zoonotic agent L. garvieae and which can differentiate it from L. lactis.

Infection with Lactococcus garvieae is considered the most important risk factor for the European trout industry, and the losses are approximately 50% of the total production. To improve our understanding of the genetic links among strains originating from different countries, we examined the population structure of L. garvieae by comparing 81 strains isolated from different sources and ecosystems (41 farms in six countries) in which the bacterium is commonly found. Genetic similarities (as assessed with molecular tools, including restriction fragment length polymorphism ribotyping with two endonucleases) were compared with serological data. The combined results reveal that in endemic sites the bacterial population displays a clonal structure, whereas bacterial diversity characterizes sites where the infection is sporadic.

Aims: To detect bacteriophages for Gram-positive oral pathogens in human saliva. Methods and Results: Saliva samples from 31 donors were screened for the presence of bacteriophages for Streptococcus sobrinus, Streptococcus mutans, Streptococcus salivarius, Actinomyces viscosus and Enterococcus faecalis. Bacteriophages for Enterococcus faecalis were found in seven samples. Enterococcus faecalis phages were still present in saliva re-collected from one donor one month, and one year after initial saliva collection. Conclusions:The presence and stability of the Enterococcus faecalis bacteriophages in human saliva suggests a possible role of these bacteriophages in the oral ecosystem. Significance and Impact of the Study: Phage therapy as a way to control oral bacteria might be considered.