Frequency of pathogens in routine bacteriological diagnosis in fish and their antimicrobial resistance / Frequência de patógenos na rotina de diagnóstico bacteriológico em peixes e sua resistência a antimicrobianos

Aquaculture is one of the sectors of animal husbandry with the fastest growth rate. However, the increase in the sector's production chain without proper management can result in factors that favor the development of diseases, especially infectious diseases caused by bacteria. Many factors, such as agriculture or industry resides, improper use of antibiotics in animals or humans, have contributed to increased environmental pressure and the appearance of antibiotic-resistant bacteria, while residues from these drugs can remain in the carcasses and in water a risk to public and environmental health. From that, we identified the bacterial genus/species and their bacterial resistance to antibiotics from samples received from fish disease outbreaks for bacteriosis diagnosis between January 2017 and October 2020. Isolated bacteria were subjected to the Kirby and Bauer sensitivity test for five classes of antibiotics (penicillins, fluoroquinolones, aminoglycosides, amphenicols, and tetracyclines). Of the 181 analyzed outbreaks, 232 bacteria were isolated, including Streptococcus spp., Aeromonas spp., Edwardsiella spp., Plesiomonas shigelloides, Pseudomonas aeruginosa, Chromobacterium violaceum, Flavobacterium spp., Citrobacter spp., Enterococcus spp., Vibrio spp., Enterobacter spp., Chryseobacterium meningosepticum. Of the 232 bacteria, 40 strains were classified as multidrug resistant (MDR), with Plesiomonas shigelloides, Aeromonas spp., and Edwardsiella spp. representing more than half of this number (22/total). With several bacteria demonstrating resistance to Brazilian aquaculture-legalized drugs (tetracycline and florfenicol), it is mandatory to research, not only for alternatives to the use of antibiotics, but also for other drugs effective against the main circulating bacterial pathogens. In addition, vigilance over the occurrence of resistant bacteria is necessary, considering the appearance of zoonotic bacteria with multi-resistant characteristics, becoming a public health concern.(AU)

Aquicultura é um dos setores da produção animal com o mais rápido crescimento. Muitos fatores, como resíduos industriais e/ou de agricultura e o uso indevido de antibióticos em animais ou humanos têm contribuído para aumentar a pressão ambiental e o aparecimento de bactérias resistentes a antibióticos contribuindo para os resíduos dessas drogas permanecerem nas carcaças e na água, o que é um risco para a saúde pública / ambiental. A partir disso, foram identificados o gênero / espécie de bactérias e sua resistência bacteriana aos antibióticos de amostras recebidas de surtos de doenças em peixes para diagnóstico bacteriológico no período entre janeiro de 2017 e outubro de 2020. As bactérias isoladas foram submetidas ao teste de sensibilidade de Kirby e Bauer para cinco classes de antibióticos (penicilinas, fluoroquinolonas, aminoglicosídeos, anfenicóis e tetraciclinas). Nos 181 surtos analisados, 232 bactérias foram isoladas, sendo estas Streptococcus spp., Aeromonas spp., Edwardsiella spp., Plesiomonas shigelloides, Pseudomonas aeruginosa, Chromobacterium violaceum, Flavobacterium spp., Citrobacter spp., Enterococcus spp., Vibrio spp., Enterobacter spp., Chryseobacterium meningosepticum dentre outras. Destas 232 bactérias, 40 cepas foram classificadas como multirresistentes (MDR), com Plesiomonas shigelloides, Aeromonas spp. e Edwardsiella spp. representando mais da metade destas (22 / total). Com várias bactérias demonstrando resistência aos medicamentos legalizados na aquicultura brasileira (tetraciclina e florfenicol), torna-se obrigatória a pesquisa, não apenas de alternativas ao uso de antibióticos, mas também de outros medicamentos eficazes contra os principais patógenos circulantes. Além disso, a vigilância sobre a ocorrência de cepas resistentes é necessária levando-se em consideração o aparecimento de bactérias zoonóticas com essa característica, tornando-se um ponto de interesse à saúde pública.(AU)

Composition of Extracellular Polymeric Substances (EPS) produced by Flavobacterium columnare isolated from tropical fish in Brazil

Thirty nine isolates of Flavobacterium columnare from Brazilian fish farms had their carbohydrate composition of EPS evaluated by high efficiency liquid chromatography, using the phenol-sulfuric acid method of EPS. The occurrence of capsules on F. columnare cells was not directly related to biofilm formation, and the predominant monosaccharide is glucose.(AU)

Occurrence of heavy metals and antibiotic resistance in bacteria from internal organs of american bullfrog (Rana catesbeiana) raised in Malaysia

A total of 40 bacteria have been successfully isolated from internal organs of the American bullfrog (Rana catesbeiana) raised in Malaysia, namely, eight isolates of Aeromonas spp., 21 of Edwardsiella spp., six of Flavobacterium spp. and five of Vibrio spp. In terms of antibiotic susceptibility testing, each isolate was tested against 21 antibiotics, resulting in 482 (57.3 percent) cases of sensitivity and 61 (7.3 percent) cases of partial sensitivity. Meanwhile, 297 (35.4 percent) bacterial isolates were registered as resistant. The multiple antibiotic resistance (MAR) index of each bacterial species indicated that bacteria from raised bullfrogs have been exposed to tested antibiotics with results ranging from 0.27 to 0.39. Additionally, high percentages of heavy metal resistance among these isolates were observed, with values ranging from 85.0 to 100.0 percent. The current results provided us information on bacterial levels of locally farmed bullfrogs exposed to copper, cadmium, chromium as well as 21 types of antibiotics.(AU)