Abstract
Fish diseases caused by bacteria or parasite infection are important problems hindering tilapia (Oreochromis niloticus) culture. Streptococcosis, due to Streptococcus spp. infection, is one of the main cause of tilapia mortality in tilapia farms. The objective was to identify the factors associated with tilapia mortality due to Streptococcus agalactiae in artisan tilapia farms in the Atiocoyo irrigation district, El Salvador, during march – June, 2022. The presence of S. agalactiae was investigated in fish, water and feed of 28 culture ponds. The serotype of the infecting bacteria was also determined. The bacteria was present only in the fish and not detected in water or feed. PCR analysis indicated that the serotypes responsible for the streptococosis were 1a and III belonging to genes cps 1 aH y cps1a/2/31 in the Polysaccharide Capsule (CPS). Physicochemical pond water parameters were also evaluated. Results of these analyses revealed a relationship between the presence S. agalactiae and dissolved water oxygen, high water temperature and elevated levels of phospahate and ammonia.
References
APHA, (2017). Standard Methods for the Examination of Water and Wastewater. 23a ed. American Public Health Association. www.standardmethods.org
Bueno, G. W., Mattos, B. O. D., Neu, D. H., David, F. S., Feiden, A. & Boscolo, W. R. (2019). Stability and phosphorus leaching of tilapia feed in water. Ciência Rural, 49.
CENDEPESCA. (2020). Anuario de estadísticas pesqueras El Salvador. Ministerio de Agricultura y Ganadería. San Salvador. 97 p.
Chen, M., Li, L. P., Wang, R., Liang, W. W., Huang, Y., Li, J. & Gan, X. (2012). PCR detection and PFGE genotype analyses of streptococcal clinical isolates from tilapia in China. Veterinary microbiology, 159(3-4), 526-530.
Deng, L., Li, Y., Geng, Y., Zheng, L., Rehman, T., Zhao, R.& Lai, W. (2019). Molecular serotyping and antimicrobial susceptibility of Streptococcus agalactiae isolated from fish in China. Aquaculture, 510, 84-89.
Dogan, B., Schukken, Y. H., Santisteban, C., & Boor, K. J. (2005). Distribution of serotypes and antimicrobial resistance genes among Streptococcus agalactiae isolates from bovine and human hosts. Journal of clinical microbiology, 43(12), 5899-5906.
FAO. (2009) Oreochromis niloticus. In Cultured aquatic species fact sheets. https://www.fao.org/fishery/docs/DOCUMENT/aquaculture/CulturedSpecies/file/es/es_niletilapia.htm
FDA. (2018). Manual Bacteriologico Analitico. Enumeración de Escherichia coli y las bacterias coliformes. Obtenido de https://www.fda.gov/food/laboratory-methods-food/bam-chapter-4-enumeration-escherichia-coli-and-coliform-bacteria
Hernández, E., Figueroa, J. & Iregui, C. (2009). Streptococcosis on a red tilapia, Oreochromis sp., farm: a case study. Journal of fish diseases, 32(3), 247-252.
Huicab-Pech, Z. G., Landeros-Sánchez, C., Castañeda-Chávez, M. R., Lango-Reynoso, F., López-Collado, C. J., & Platas Rosado, D. E. (2016). Current state of bacteria pathogenicity and their relationship with host and environment in tilapia Oreochromis niloticus. Journal of aquaculture research and development, 7(5), 1-10.
Evans, J. J., Wiedenmayer, A. A., Klesius, P. H., & Shoemaker, C. A. (2004). Survival of Streptococcus agalactiae from frozen fish following natural and experimental infections. Aquaculture, 233(1-4), 15-21.
MAG. (2012). Caracterización de la cadena productiva de Acuicultura – Tilapia. IICA. San Salvador. 63 p.
Marroquín-Mora, C., & García-Pérez, J. (2016). Aplicación de inmunoestimulantes de origen natural en el cultivo de tilapia para la prevención de Estreptococosis en Guatemala. Informe, 4(26.2), 46.
Najiah, M., Aqilah, N. I., Lee, K. L., Khairulbariyyah, Z., Mithun, S., Jalal, K. C. A., & Nadirah, M. (2012). Massive mortality associated with Streptococcus agalactiae infection in cage-cultured red hybrid tilapia Oreochromis niloticus in Como River, Kenyir Lake, Malaysia. Journal of Biological Sciences, 12(8), 438-442.
NICOVITA Alicorp. 2014. Manual de crianza de tilapia. Condiciones y parámetros de cultivo. 3, 6-15 p. Lima, Perú (en línea). Consultado el 11 de marzo 2023. Disponible en: http://www.industriaacuicola.com/biblioteca/Tilapia/Manual%20de%20crianza%20de%20tilapia.pdf
Oviedo Bolaños, K., Rodríguez-Rodríguez, J. A., Sancho-Blanco, C., Barquero-Chanto, J. E., Peña-Navarro, N., Escobedo-Bonilla, C. M., & Umaña-Castro, R. (2021). Molecular identification of Streptococcus sp. and antibiotic resistance genes present in Tilapia farms (Oreochromis niloticus) from the Northern Pacific region, Costa Rica. Aquaculture International, 29(5), 2337-2355.
Perdomo, Y., & Vasquez, K. (2023) Determinaciones fisicoquimicas y presencia de Streptococcus agalactiae en granjas de tilapia (Oreochromis niloticus) del Distrito de riego de Atiocoyo sur. [Tesis. Universidad de El Salvador, 2023)]. Universidad de El Salvador. https://ri.ues.edu.sv/id/eprint/31282/
Poyart, C., Tazi, A., Réglier-Poupet, H., Billoët, A., Tavares, N., Raymond, J., & Trieu-Cuot, P. (2007). Multiplex PCR assay for rapid and accurate capsular typing of group B streptococci. Journal of clinical microbiology, 45(6), 1985-1988.
Pulido-Colina, A., Pastrana, J. S., Valencia-Bazalar, E., & Apestegui, M. Z. (2022). Caracterización molecular de genes de virulencia (lmb, bca y rib) y de resistencia a macrólidos (ermB, ermTR y mefA) en aislamientos clínicos de Streptococcus agalactiae. Revista Peruana de Medicina Experimental y Salud Publica, 38, 615-620.
Saavedra, M. (2006). Manejo del Cultivo de Tilapia. USAID Managua. 13p.
Ye, X., Li, J., Lu, M., Deng, G., Jiang, X., Tian, Y. & Jian, Q. (2011). Identification and molecular typing of Streptococcus agalactiae isolated from pond-cultured tilapia in China. Fisheries Science, 77, 623-632.
Zhang, D., Li, A., Guo, Y., Zhang, Q., Chen, X. & Gong, X. (2013). Molecular characterization of Streptococcus agalactiae in diseased farmed tilapia in China. Aquaculture, 412, 64-69.

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