Aeromonas Hydrophila

Aeromonas hydrophila is a gram negative rod bacterium. This bacterium spreads widely in various environments, especially in fresh water like in fish cultivation ponds, rivers, lakes, even in sparkling chlorinated drinking water reservoirs. This bacterium is known as a dangerous pathogenic bacterium in water biota like shrimps, oysters, frogs, and fishes (Martin-Carnahan & Joseph, 2005; EPA, 2006). The infection caused by this bacterium can lead to mass dead of fish in short period of time, which in turn causing a great loss of fishes. Formally, in a stable condition when the fish are not in stress, A. hydrophila existing in fish intestine has a role as microflora for water creatures (Illanchezian et al., 2010; Mangunwardoyo et al., 2010). A.

The difficulty of differentiating A. hydrophila from other species in taxon Aeromonas comes from the complexity of taxonomy with various characters, even at the level of intraspecies (Soler et al., 2004; Ottaviani et al., 2011). The identification using the classical phenospecies still bears many mistakes. This has been proven by Beaz-Hidalgo et al. (2010) that based on the latest Bergey`s Manual of Systematic Bacteriology, the positive test of ADH and hydrolysis cannot differentiate the A. hydrophila from A. sorbria. This conventional identification method still allows other bacteria with similar phenotypes to be identified as the same species, whereas probably they are not genetically the same. Besides that, the conventional phenospecies method needs very intensive efforts, using many chemicals and consuming much time, for example the identification using the biochemical test for Aeromonas sp. developed by Abbot et al.

hydrophila in various water sources and foodstuffs becomes a problem. Its existence with the virulence in cultivation ponds of freshwater organisms, such as in fish or shrimp cultivation ponds, is a hidden danger that can be the time bomb that can explode any time. When the environment is worsening, it can be a deadly plague for the fresh water creatures in a short time. The mass death of gourami fish in just three days happened in Tasikmalaya, Indonesia, in 2003, which caused a great loss of fishes (Holipah, 2006). In laboratory scale, the concentration 105 – 1010 cfu/ml of A. hydrophila injected into 7-9 cm lele fish resulted in fish death, starting six hours after infection. The 100% death may be reached 2-3 days after the infection with a dose of 107 – 108 cfu/ml, but 6-7 days with a dose of 105 – 106 cfu/ml (Triyaningsih et al., 2014). It is also known that A. hydrophila is frequently related to human diarrhea; as reported by Alberts et al. (1990), 12.2% of toddlers with acute diarrhea in Dhaka, Bangladesh, were positive to have A. hydrophila. Based on those facts, a quick monitoring system is needed to monitor the fluctuation of A. hydrophila concentration in fish cultivation ponds and also to make the quality control of drinking water source more