GROUP 4: ANTIMICROBIAL SUSCEPTIBILITY TESTING FOR SELECETED SPECIES

GROUP 4: ANTIMICROBIAL SUSCEPTIBILITY TESTING FOR SELECETED SPECIES

CARPS-Bacterial species of importance Aeromonas sp. (A. hydrohila, A. veronii, A. sorbia, A. caviae, A. schubertii, except A. salmonicida) Pseudomonas fluorescens Flavobacterium columnae Yersinia ruckerii Streptococcus agalactiae, S. inaea Erdwardsiella tarda

TILAPIA-Bacterial species of importance Aeromonas sp (except A. salmonicida) Pseudomonas fluorescens Flavobacterium columnae Streptococcus agalactiae, S. inaea Erdwardsiella tarda Francisella noatunensis Vibrio sp. Mycobacterium

CATFISH-Bacterial species of importance Pangasius catfish Edwardsiella ictaluri, E. tarda Aeromonas sp. Flavobacterium columnae

SHRIMPS-Bacterial species of importance Vibrio sp. Aeromonas sp. (in low salinity culture, vietnam) Providencia rettgeri (china)

List of antibiotics of interest Gram Positive (+) Florfenicol Enrofloxacin Trimethoprim/sulfamethoxazole, Ormetoprim/sulfadimethoxine Neomycin Oxytetracycline Doxycycline Amoxicillin/Ampicillin Flumequine Erythromycin Tetracycline Thiamphenicol (permitted in China) Chloramphenicol Gram Negative (-) Florfenicol Enrofloxacin Trimethoprim/sulfamethoxazole, Ormetoprim/sulfadimethoxine Oxytetracycline Doxycycline Amoxicillin Flumequine Chloramphenicol Nitrofurantoin Colistin (?)

Capacity and capability in 4 countries Methods CHINA PHILIPPINES VIETNAM MALAYSIA 1. Disc Diffusion 2. MIC Agar Broth Auto 3. Reading Machine Manual Auto (disk) (vitek, MOH)

AST- Vietnam S agalactiae S. inae Aeromonas sp. except A. salmonicida Incubation Temperature 28 28 28 Blood OR Salt requirement - - - AST Media MHA (DD) MHA (DD) MHA (DD) Main antibiotic tested (used in aquaculture) Doxycline Oxytertracycline Erythromycin Ampicillin Florfenicol Streptomycin Cyprofloxacin Trimethoprim/sulfamethoxazole Tetracycline Reference strain: i. E. coli (ATCC 25922) OR ii. A. salmonicida (ATCC 33658) -every time you do your testing Underlined antibiotics- with quality control readings

AST- Malaysia V. parahaemolyticus Incubation Temperature 28 Blood OR Salt requirement - AST Media MHA (DD) Main antibiotic tested (used in aquaculture) Nitrofurantoin Amoxicillin/Ampicillin Oxytetracycline Chloramphenicol, Florfenicol Enrofloxacin Trimethoprim/sulfamethoxazole Erythromycin Ormetoprim/sulfadimethoxine Reference strain: i. E. coli (ATCC 25922) OR ii. A. salmonicida (ATCC 33658) - everytime you do your testing Underlined antibiotics- with quality control readings

AST-China S. agalactiae S. inae Aeromonas sp except A. salmonicida Vibrio Incubation Temperature 28 28 28 28 28 Blood OR Salt requirement - - - Edwardsiella tarda AST Media MHA/MHB MHA/MHB MHA/MHB MHA/MHB MHB/MHB Main antibiotic tested (used in aquaculture) Doxycline Oxytertracycline Erythromycin Ampicillin Florfenicol Streptomycin Cyprofloxacin Trimethoprim/sulfamethoxazole Tetracycline Neomycin Enrofloxacin Reference strain: i. E. coli (ATCC 25922) OR ii. A. salmonicida (ATCC 33658) - everytime you do your testing Underlined antibiotics- with quality control readings

AST- The Philippines S agalactiae S. inae Vibrio sp Aeromonasspp Incubation Temperature 28 28 28 28 Blood requirement/salt - - - - AST Media MHA MHA MHA MHA Main antibiotic tested (used in aquaculture) Doxycline Oxytetracycline Erythromycin Ampicillin Florfenicol Streptomycin Cyprofloxacin Trimethoprim/sulfamethoxazole Tetracycline Chloramphenicol Nitrofuran Sulfamethazine Amoxicillin Underlined antibiotics- with quality control readings Reference strain: i. E. coli (ATCC 25922) OR ii. A. salmonicida (ATCC 33658) - everytime you do your testing

AST METHOD Will not be discussed in this group. Refer to the standard method. Refer to Dr Peter Smith if you have any questions.

INTERPRETING AST RESULTS Purpose of AST i. want to know whether the bacteria is Resistant or Sensitive ii. Want to know whether the drugs going to work or not Results from AST- divide the bacteria : - fully sensitive (wild type, WT) - not fully sensitive (Non Wild Types, NWT) With zones sizes of 20-30 isolates we may get the epidemiological cut off value,? How do you set the epidemiological cut-off value? - There is a website to help do this. Epidemiological cut-off value is specific for one method, one antibiotic and one bacterial species. Epidemiological cut-off value could help the lab to advice the farmers on the next course of action regarding whether to start antibiotic treatment or not

WAY FORWARD Make decision about temperature of choice (for some bacteria). Make a decision about salt/blood requirement in MHA/MHI (for Streptococcus sp.) Attempt to arrange the report shape. Thinking about training program for AST (of course with Dr Melba s help J).