Thesis (M.Sc)-Cairo University, 2025.

Bibliography: pages 118-141.

Although aquaculture is essential to the world's food security, climate change is having a greater impact on it since it changes the ecosystem, impairs fish health, and increases the danger of illness. Antimicrobial- resistant (AMR) bacteria, such as Pseudomonas aeruginosa (P. aeruginosa) and Escherichia coli (E. coli), are spreading due to rising temperatures and pH variations, endangering public health and food safety. Thus, 328 Nile Tilapia (Oreochromis niloticus) from Egyptian fish farms were gathered and categorized according to environmental and seasonal fluctuations. P. aeruginosa and E. coli were isolated and identified using molecular techniques. P.aeruginosa was highly prevalent (95.12%) in all fish groups, reaching its peak in the summer, and its virulence genes, such as exoS, ToxA, oprL, and phzM, increased with temperature. Investigating the genes for β- lactamase and carbapenemase resistance using PCR showed that blaTEM and blaOXA-48 dominated were most frequent in the summer, and phylogenetic analysis linked P. aeruginosa isolates to humans associated strains. The prevalence of E. coli was notably high (92.68%) and showed a strong correlation with increased water temperatures. Diarrheagenic E. coli was detected in 82.1% of the samples, with enterotoxigenic E. coli (ETEC) identified as the predominant (86.84%) pathotype.

Hybrid strains carrying multiple virulence markers were detected, and resistance genes such as blaTEM, blaCTX-M, and blaOXA-48 were widespread in warmer months. Environmental stressors, including temperature and pH fluctuations, contributed to increased resistance and virulence in both bacterial species. Rising temperatures and pH imbalances, likely driven by climate change, contribute to increased bacterial virulence and antimicrobial resistance in aquaculture. This study highlights the need for proactive management, including routine monitoring and improved sanitation, to mitigate these risks and ensure sustainable aquaculture and public health safety.

ﺗﻌﺪ ﺗﺮﺑﯿﺔ اﻷﺣﯿﺎء اﻟﻤﺎﺋﯿﺔ ﺿﺮورﯾﺔ ﻟﻸﻣﻦ اﻟﻐﺬاﺋﻲ ﻋﺎﻟﻤﯿﺎ، إﻻ أن ﺗﻐﯿﺮ اﻟﻤﻨﺎخ ﻗﺪ ﯾﻜﻮن ﻟﮫ ﺗﺄﺛﯿﺮ ﻛﺒﯿﺮ ﻋﻠﯿﮭﺎ, ﻣﻦ ﺣﯿﺚ أﻧﮫ ﯾﻐﯿﺮ اﻟﻨﻈﺎم اﻟﺒﯿﺌﻲ، وﯾﻀﻌﻒ ﺻﺤﺔ اﻷﺳﻤﺎك، وﯾﺰﯾﺪ ﻣﻦ ﺧﻄﺮ اﻹﺻﺎﺑﺔ ﺑﺎﻷﻣﺮاض. وﻧﺘﯿﺠﺔ ﻻرﺗﻔﺎع درﺟﺎت اﻟﺤﺮارة وﺗﻐﯿﺮات درﺟﺔ اﻟﺤﻤﻮﺿﺔ ﻗﺪ ﺗﻨﺘﺸﺮ اﻟﺒﻜﺘﯿﺮﯾﺎ اﻟﻤﻘﺎوﻣﺔ ﻟﻤﻀﺎدات اﻟﻤﯿﻜﺮوﺑﺎت، ﻣﺜﻞ اﻟﺰاﺋﻔﺔ اﻟﺰﻧﺠﺎرﯾﺔ aeruginosa) (P. واﻹﺷﺮﯾﻜﯿﺔ اﻟﻘﻮﻟﻮﻧﯿﺔ coli) (E.، ﻣﻤﺎ ﯾﻌﺮض اﻟﺼﺤﺔ اﻟﻌﺎﻣﺔ وﺳﻼﻣﺔ اﻷﻏﺬﯾﺔ ﻟﻠﺨﻄﺮ وﻟﺬا ﻓﻘﺪ ﺗﻢ ﺟﻤﻊ ۳۲۸ ﻋﯿﻨﺔ ﻣﻦ أﺳﻤﺎك اﻟﺒﻠﻄﻲ اﻟﻨﯿﻠﻰ niloticus) (Oreochromis ﻣﻦ ﺑﻌﺾ اﻟﻤﺰارع اﻟﺴﻤﻜﯿﺔ اﻟﻤﺼﺮﯾﺔ وﺗﻢ ﺗﺼﻨﯿﻔﮭﺎ ﺣﺴﺐ اﻟﺘﻐﯿﺮات اﻟﺒﯿﺌﯿﺔ واﻟﻤﻮﺳﻤﯿﺔ. و ﺑﺎﺳﺘﺨﺪام اﻟﺘﻘﻨﯿﺎت اﻟﺠﺰﯾﺌﯿﺔ ﺗﻢ ﻋﺰل اﻟﻤﯿﻜﺮوﺑﺎت ﻣﻦ اﻟﻨﻮع P. aeruginosa وcoli .E. ﺣﯿﺚ ﻛﺎﻧﺖ ﻣﯿﻜﺮوﺑﺎت P.aeruginosa ﻣﻨﺘﺸﺮة ﺑﺸﻜﻞ ﻛﺒﯿﺮ (۱۲ ۹٥٫ ٪) ﻓﻲ ﺟﻤﯿﻊ ﻣﺠﻤﻮﻋﺎت اﻷﺳﻤﺎك اﻟﻤﻔﺤﻮﺻﺔ، ووﺻﻠﺖ إﻟﻰ ذروﺗﮭﺎ ﻓﻲ اﻟﺼﯿﻒ، وﺳﺠﻠﺖ اﻟﺪراﺳﺔ زﯾﺎدة ﻓﻰ ﻣﻌﺪل ﺟﯿﻨﺎت اﻟﻀﺮاوة اﻟﺨﺎﺻﺔ ﺑﺎﻟﻤﯿﻜﺮوب، ﻣﺜﻞ exoS، وToxA، وoprL، وphzM، ﻣﻊ ارﺗﻔﺎع درﺟﺔ اﻟﺤﺮارة. و ﺑﺎﺳﺘﺨﺪام ﺗﻘﻨﯿﺔ ﺗﻔﺎﻋﻞ اﻟﺒﻠﻤﺮة اﻟﻤﺘﺴﻠﺴﻞ ﻟﻠﻜﺸﻒ ﻋﻦ ﺗﻮاﺟﺪ اﻟﺠﯿﻨﺎت اﻟﺨﺎﺻﺔ ﺑﻤﻘﺎوﻣﺔ اﻟﺒﯿﺘﺎ ﻻﻛﺘﺎﻣﺎز واﻟﻜﺎرﺑﺎﺑﯿﻨﯿﻤﺎز, وﺟﺪ أن blaTEM و blaOXA-48 ﻛﺎﻧﺎ أﻛﺜﺮ ﺷﯿﻮﻋًﺎ ﻓﻲ ﻓﺼﻞ اﻟﺼﯿﻒ، و ﺑﺎﺟﺮاء ﺗﺤﻠﯿﻞ اﻟﻨﺸﻮء واﻟﺘﻄﻮر ﻟﻠﺠﯿﻦ oprL وﺟﺪ أن ھﻨﺎك ﺗﺸﺎﺑﺔ ﺑﯿﻦ ﻋﺰﻻت aeruginosa P.اﻟﻤﻌﺰوﻟﺔ ﻣﻦ ﻋﯿﻨﺎت اﻷﺳﻤﺎك و اﻟﺴﻼﻻت اﻟﻤﺮﺗﺒﻄﺔ ﺑﺎﻟﺒﺸﺮ اﻟﺘﻰ ﺗﻮﺟﺪ ﻋﻠﻰ ﺑﻨﻚ اﻟﺠﯿﻨﺎت. وﻋﻠﻰ اﻟﺠﺎﻧﺐ اﻷﺧﺮ ﻓﻘﺪ ﻛﺎن ﻣﻌﺪل اﻧﺘﺸﺎرﻣﯿﻜﺮوب اﻹﺷﺮﯾﻜﯿﺔ اﻟﻘﻮﻟﻮﻧﯿﺔ ﻣﺮﺗﻔﻌًﺎ ﺑﺸﻜﻞ ﻣﻠﺤﻮظ ( ٨ ٦ ,۹۲ ٪). وأظﮭﺮ ارﺗﺒﺎطًﺎ ﻗﻮﯾًﺎ ﺑﺎرﺗﻔﺎع درﺟﺎت ﺣﺮارة اﻟﻤﯿﺎه. ﻛﻤﺎ ﺗﻢ اﻛﺘﺸﺎف ﻣﯿﻜﺮوب اﻹﺷﺮﯾﻜﯿﺔ اﻟﻘﻮﻟﻮﻧﯿﺔ اﻟﻤﺴﺒﺒﺔ


ﻟﻺﺳﮭﺎل ﻓﻲ) ۸۲٫۱ ٪ (ﻣﻦ اﻟﻌﯿﻨﺎت، وﺗﻢ ﺗﺤﺪﯾﺪ اﻹﺷﺮﯾﻜﯿﺔ اﻟﻘﻮﻟﻮﻧﯿﺔ اﻟﻤﻌﻮﯾﺔ (ETEC) ﻋﻠﻰ أﻧﮭﺎ اﻟﻨﻤﻂ اﻟﻤﺮﺿﻲ اﻟﺴﺎﺋﺪ ( ۸٤, ٦ ۸ ٪.( وﻛﺸﻔﺖ اﻟﺪراﺳﺔ ﻋﻦ ﺗﻮاﺟﺪ ﺳﻼﻻت ھﺠﯿﻨﺔ ﺗﺤﻤﻞ ﺟﯿﻨﺎت ﺿﺮاوة ﻣﺘﻌﺪدة، ﻛﻤﺎ اﻧﺘﺸﺮت ﺟﯿﻨﺎت اﻟﻤﻘﺎوﻣﺔ ﻣﺜﻞ blaTEM ، وblaCTX-M ، و blaOXA-48 ﻓﻲ اﻟﻤﯿﻜﺮوب ﻓﻰ اﻷﺷﮭﺮ اﻷﻛﺜﺮ دﻓﺌًﺎ ﻣﻦ اﻟﻌﺎم. وﻗﺪ ﺧﻠﺼﺖ اﻟﺪراﺳﺔ اﻟﻰ أن اﻟﻀﻐﻮط اﻟﺒﯿﺌﯿﺔ، ﺑﻤﺎ ﻓﻲ ذﻟﻚ ﻣﻦ ﺗﻐﯿﺮات ﻓﻰ درﺟﺔ اﻟﺤﺮارة ودرﺟﺔ اﻟﺤﻤﻮﺿﺔ، ﻗﺪ ﺗﺴﺎھﻢ ﻓﻲ زﯾﺎدة اﻟﻤﻘﺎوﻣﺔ واﻟﻀﺮاوة ﻟﻠﻤﺴﺒﺒﺎت اﻟﻤﺮﺿﯿﺔ اﻟﻤﻌﺰوﻟﺔ ﻣﻦ ﻋﯿﻨﺎت اﻷﺳﻤﺎك. و ﺑﺎﻟﺘﺎﻟﻰ ﻓﺎن ارﺗﻔﺎع درﺟﺎت اﻟﺤﺮارة واﺧﺘﻼل ﺗﻮازن اﻷس اﻟﮭﯿﺪروﺟﯿﻨﻲ، اﻟﻨﺎﺟﻢ ﻋﻠﻰ اﻷرﺟﺢ ﻋﻦ ﺗﻐﯿﺮ اﻟﻤﻨﺎخ، ﻗﺪ ﯾﺴﺎھﻢ ﻓﻰ زﯾﺎدة ﺿﺮاوة اﻟﻤﯿﻜﺮوﺑﺎت وﻣﻘﺎوﻣﺘﮭﺎ ﻟﻤﻀﺎدات اﻟﻤﯿﻜﺮوﺑﺎت ﻓﻲ ﺗﺮﺑﯿﺔ اﻷﺣﯿﺎء اﻟﻤﺎﺋﯿﺔ. ﻟﺬا ﻓﻘﺪ ﺳﻠﻄﺖ ھﺬه اﻟﺪراﺳﺔ اﻟﻀﻮء ﻋﻠﻰ ﺿﺮورة اﻟﻤﺮاﻗﺒﺔ اﻟﺮوﺗﯿﻨﯿﺔ وﺗﺤﺴﯿﻦ اﻟﺼﺮف اﻟﺼﺤﻲ، ﻟﻠﺘﺨﻔﯿﻒ ﻣﻦ ھﺬه اﻟﻤﺨﺎطﺮ وﺿﻤﺎن ﺗﺮﺑﯿﺔ اﻷﺣﯿﺎء اﻟﻤﺎﺋﯿﺔ اﻟﻤﺴﺘﺪاﻣﺔ وﺳﻼﻣﺔ اﻟﺼﺤﺔ اﻟﻌﺎﻣﺔ.

Issues also as CD.

Text in English and abstract in Arabic & English.