1.Distribution and prevalence of antibiotic resistant bacteria in fish farms in East Malaysia
Samuel Lihan ; Nurul Asyiqin Jamil ; Mohd Azizul Hafiz Jamian ; Toh Seng Chiew ; Olaide Olawunmi Ajibola ; Sabella Justin ; Flonia Benet ; Lee Nung Kion
Malaysian Journal of Microbiology 2020;16(4):263-274
Aims:
Aquaculture has grown tremendously in Malaysia over the past decades. However, guaranteeing aquaculture
sustainability is a big challenge in terms of maintaining continuous output with a safe environment. Furthermore, the
cultured species should be free from antibiotic resistance bacterial and antibiotic residue. This study aimed to monitor
the existence and prevalence of antibiotic resistant bacteria associated with aquaculture farms in Sarawak.
Methodology and results:
Samples of water, sediment and fish were collected from five aquaculture farms within
Sarawak. The samples were plated on trypticase soy agar and incubated at 28 °C for 24 h. A total of 204 bacterial
isolates were isolated and analysed by (GTG)5-fingerprinting to determine genetic similarity among the bacterial isolates,
so that representatives could be selected from similar clonal isolates. Based on the (GTG)5 profiles, 50 representative
isolates were chosen for species identification using 16S rRNA sequencing. The identified bacteria were tested against
25 antibiotics using standard disk diffusion method. The 16S rRNA analysis revealed that the isolates constitute of 14
genera of bacteria including Bacillus (38%), Exiguobacterium (16%), Enterobacter (14%), Aeromonas (6%),
Acinetobacter (4%), Citrobacter (4%), Staphylococcus (4%), Achromobacter (2%), Chitinophaga (2%), Fictibacillus (2%),
Plesiomonas (2%), Pseudomonas (2%), Pseudoxanthomonas (2%) and Stenotrophomonas (2%). The antibiotic
resistance analysis revealed that the highest percentage of resistance was recorded against streptomycin (75.0%),
followed by ampicillin (66.0%), ceftriaxone (50.0%), rifampin (43.3%), aztreonam (36.8%) and ceftazidime (31.6%).
Resistance to more than two antibiotics was observed in 40.0% of isolates with an overall multiple antibiotic resistant
(MAR) index ranging from 0 to 0.79.
Conclusion, significant and impact of study
The variability of antibiotic resistance patterns exhibited by different
bacterial species suggests a dependence on selective pressures exhibited in different geographical locations. Our
results show that the occurrence of MAR bacteria in an aquaculture environment with unknown history of antibiotics
usage in the aquaculture system is possible, indicating a need to continuously monitor the presence of antibiotic
resistant bacteria in the aquaculture system.
Drug Resistance, Microbial
;
Aquaculture
;
Malaysia