Mycobacterium

African Journal of Microbiology Research Vol. 6(11), pp. 2785-2787, 23 March, 2012 Available online at http://www.academicjournals.org/AJMR DOI: 10.5897/AJMR11.1493 ISSN 1996-0808 ©2012 Academic Journals

Full Length Research Paper

Detection of Mycobacterium spp. by polymerase chain reaction in Nile tilapia (Oreochromis niloticus) in Campeche, Mexico
Karina Y. Sonda-Santos and MaurilioLara-Flores*
Instituto de Ecología, Pesquerías y Oceanografía del Golfo de México, Universidad Autónoma de Campeche, Av. Agustín Melgar y Juan de la Barrera S/N, Col. Buenavista. C.P. 24039. San Francisco de Campeche, Campeche, México.
Accepted 17 January, 2012

Mycobacteriosis is one of the serious diseases that affect a wide range of cultured fishes which is also dangerous for human. The aim ofthis study is to confirm the presence of Mycobacterium spp. that has been reported in 2007 in Campeche, Mexico. For this purpose, we evaluate fishes from a tilapia farm that previously reported clinical signs similar to Mycobacteriosis like granulomas. At first, the specific culture for Mycobacterium was done and, then, polymerase chain reaction (PCR) for detection of Mycobacterium spp. was used.Out of 30 evaluated specimens, 15 were suspected to be Mycobacterium spp. after Ziehl-Neelsen stain. PCR uses specific primers for Mycobacterium spp. and 8 samples were revealed positive. The results of this study confirm the presence of this group of pathogens in the region and could affect the development of the aquaculture in Campeche. Key words: Mycobacterium spp., Nile tilapia, Oreochromisniloticus, fish disease, polymerase chain reaction (PCR) Campeche, Mexico. INTRODUCTION Mycobacteriosis has been reported to affect a wide range of freshwater and marine fish species, suggesting a ubiquitous distribution (Gauthier and Rhodes, 2009; Jacobs et al., 2009). In general, mycobacteriosis in fish described as a systematic, chronic, progressive disease with clinical signs that include skindiscoloration, loss of appetite, lethargy, abnormal swimming behavior, isolation, cutaneous ulcerations or erosions, ascites, reduced growth, and exophthalmia (Austin and Austin, 2007; Gauthier et al., 2010). Factors that may predispose fish to mycobacterial infection include dietary or environmental contamination, stress associated with overcrowding, suboptimal nutrition, and poor water quality(Smith, 1997; Bozzetta et al., 2010). Mycobacteriosis has the potential to profoundly impact commercial fisheries, sport fisheries, aquaculture enterprises, and public and private ornamental aquaria. Economically significant consequences include mortality, morbidity, and effects of subclinical infection such as decreased feed efficiency, decreased growth rates, and decreased marketability (Zanoni etal., 2008). Tilapia fish has been part of the local government plans for aquaculture extension since 1980´s as an important alternative to fisheries. Since 2004 the local government wanted to know the present situation of this activity with the purpose of ordering and planning it. As part of cultured aquatic animal health surveillance program tilapia fish were sampled with the aim to establishtheir health status. The present works identify infected fishes by PCR method in order to detect Mycobacterium spp., and in a subsequent study determine the species of these bacteria using molecular phylogenetic inference methods.
MATERIALS AND METHODS Sampling and isolation of bacterium

*Corresponding author. E-mail: maurilio_lara@yahoo.com.mx or maurlara@uacam.mx. Tel: +52 (981) 8119800 ext:62311.

As part of an aquatic animal program, a tilapia farm which recently

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Figure 1. Preventative amplification products from infected tilapia using PCR assay for the detection of Mycobacterium spp. lanes: M DNA Ladder, lanes 1-4 samples isolated from infected fishes

initiated operation in Campeche State, southern of Mexico was visited. Thirty fry of...