AAVS_14_5_1091-1099

INTRODUCTION

Antibiotic resistance is a serious threat to public health worldwide, highlighting the health crisis associated with the global increase in infections caused by pathogens resistant to late-generation antibiotics (Antimicrobial Resistance Collaborators, 2022). In this sense, companion animals are frequently exposed to antibiotics due to treatment or prevention of infections or through the consumption of food products (Guardabassi et al., 2004; Ramos et al., 2022), increasing selective pressure and leading to the development of multidrug resistance (MDR) in their commensal bacteria (Wu et al., 2019). Thus, pets can be reservoirs and hosts for resistant bacteria, raising concerns about the risks to both human and animal health (Carvalho et al., 2021; Yuan et al., 2024).

Escherichia coli (E. coli) is one of the most common microorganisms in the gut microbiota and is frequently subjected to antibiotic selective pressure. Therefore, testing for antibiotic resistance in E. coli strains isolated from fecal samples is a good indicator for assessing the level of drug resistance (Marchetti et al., 2021). E. coli are highly susceptible to antibiotic pressure and have a very high potential for developing antibiotic resistance, leading to an increase in the number of MDR strains and even those that are almost completely resistant to all antibiotics. MDR is defined as insensitivity to at least one agent in three or more antibiotic classes (Magiorakos et al., 2012). MDR pathogens can cause more severe, prolonged infections and ultimately have the potential to cause global pandemics (Cummins et al., 2021).

In Vietnam, current research on antibiotic resistance mainly focuses on food-producing animals, such as livestock and poultry. However, due to close contact between companion animals and humans, bacteria including E. coli, Salmonella spp., etc., isolated from dogs and cats have a high degree of similarity to strains isolated from humans, increasing the potential for interspecies transmission of antibiotic-resistant E. coli and posing a potential threat to human health (Derakhshandeh et al., 2018). To date, data on antibiotic resistance levels in bacteria isolated from pets and companion animals, such as E. coli and Salmonella spp., is very limited in Vietnam. This study aimed to investigate the prevalence and phenotype of antibiotic resistance in E. coli strains obtained from dogs and cats at veterinary clinics in Hanoi, Vietnam.

MATERIALS AND METHODS

Sample collection

In this cross-sectional study, from November 2024 to December 2025, one-hundred and sixty-one dog (n=92) and cat (n=69) fecal samples were randomly collected from twelve veterinary clinics in Hanoi, Vietnam. Healthy dogs and cats are those brought to the veterinary clinic for vaccinations, grooming, and deworming. Sick dogs and cats are those suffering from gastrointestinal illness or diarrhea and receiving treatment at the veterinary clinic. The samples were collected according to the QCVN 01-83:2011/BNNPTNT guidelines of the Ministry of Agriculture and Rural Development (2011). Briefly, fecal samples were carefully collected using the rectal swab sampling with sterile cotton swabs. Each sample was placed in a separate sterile sample bag, labeled, stored at 4 °C in a dry ice box, and immediately transported to the Department of Veterinary Microbiology and Infectious Diseases, Faculty of Veterinary Medicine, Vietnam National University of Agriculture for analysis within 24 hours.

Escherichia coli isolation

The isolation and identification of E. coli was performed as previous studies described with some modification (Mustapha et al., 2021; Yuan et al., 2024). Briefly, at the laboratory, each feces sample was homogenized with buffer peptone water (BPW; Merck, Germany). Next, a loopful of the homogenized cultures was streaked onto MacConkey agar (Merck, Germany) and incubated at 37°C for 24 hours. Subsequently, the pink colonies (Figure 1) were cultured onto eosin methylene blue agar (EMB; Merck, Germany) and incubated at 37°C for 24 hours. Then, a typical colony exhibiting the green metallic sheen on EMB agar (Figure 2) were streaked into a triple sugar iron (TSI; Merck, Germany) agar tube and incubated at 37 °C for 24 hours. Colonies exhibiting a typical TSI profile, including glucose and lactose fermentation with gas production and no H2S, (Figure 3), were identified as E. coli by Gram staining and biochemical tests, such as indole production, methyl red, Voges-Proskauer, and citrate utilisation reactions, with the expected IMViC result being “++--” (Figure 4). All isolates were kept in brain heart infusion broth (BHI; Merck, Germany) plus 50% glycerin at minus 20 °C for the next experiment.

Antimicrobial susceptibility testing

A total of 96 E. coli strains from positive samples were selected for antibiotic susceptibility analysis, according to the Clinical and Laboratory Standards Institute guidelines (CLSI, 2020). Agar diffusion method (Figure 5) was performed on Mueller-Hinton agar (MHA, Merck, Germany) following Bauer et al. (1966). Eleven different antibiotic agents (Oxoid, UK) belonging to seven classes were used, including penicillins (ampicillin, 10 µg) cephalosporin (cefotaxime, 30 µg), carbapenem (meropenem, 10 µg), tetracyclines (doxycycline, 30 µg; tetracycline, 30 µg), aminoglycosides (gentamicin, 10 µg; streptomycin, 30 µg), quinolones (nalidixic acid, 30 µg; norfloxacin, 10 µg) and sulfonamides (sulfonamides, 300 µg; trimethoprim/sulfamethoxazole, 1.25/23.75 µg). The Escherichia coli ATCC 25922 strain was used for quality control. One E. coli strain was classified as a resistant isolate following the confirmation of resistance to at least one tested antibiotic. It was further designated as a MDR strain upon confirmation of resistance to at least one antibiotic from three different antibiotic classes (Magiorakos et al., 2012).

Data analysis

Data on E. coli isolates and antimicrobial susceptibility tests were recorded in a Microsoft Excel spread sheet where edits were done. The Fisher’s exact test was used to assess differences in prevalence and antibiotic susceptibility of E. coli isolates between the sample types, and values of p < 0.05 were considered significant.

RESULTS AND DISCUSSION

In the current study, E. coli was identified in 59.6% of the fecal samples (Table 1). There was no difference in the isolation rates of E. coli between dog and cat fecal samples, 59.8% in dog fecal samples and 59.4% in cat fecal samples (p > 0.90). However, E. coli was more prevalent in diarrheal compared to healthy dog and cat samples, with rates of 64.4% and 55.7% (p = 0.3331), respectively. Overall, the isolation rates of E. coli were lower than that in West Indies, European countries and Zimbabwe (Amandi et al., 2019; Joosten et al., 2020; Matope et al., 2024), reported that 93.0 - 98.6% of the feces samples collected from dogs and cat were E. coli -positive. Moreover, E. coli was identified in 78.2% and 91.9% of the feces samples from cat and dogs in Australia, respectively (Bourne et al., 2019). However, this rate could comparable to those in previous studies in China (Tong et al., 2023; Zhou et al., 2021), reported that E. coli were identified in 63.75-63.92% of the dog and cat fecal samples. The high prevalence of E. coli observed in feces samples of dogs and cats demonstrates the reason why E. coli is often selected to determine antibiotic resistance in both human and veterinary medicine (Joosten et al., 2020; Matope et al., 2024).

The E. coli strains were resistant to ampicillin, streptomycin and tetracycline at the rates of 68.8%, 65.6%, and 47.9% (Table 2), respectively. Previous studies in China have reported high resistance rates in dog and cat-derived E. coli strains to these antibiotics (Zhou et al., 2022; Yuan et al., 2024). Additionally, moderate resistance rates ranging from 32.6% to 50.5% have been observed in E. coli strains in previous studies in Argentina (Marchetti et al., 2021), Indonesia, and Timor-Leste (Nugroho et al., 2024). Conversely, the rate of antibiotic resistance was lower in E. coli strains in previous studies in Australia (Bourne et al., 2019), European countries (Joosten et al., 2020), Canada (Leonard et al., 2012; Awosile et al., 2018), Argentina (Marchetti et al., 2021), South Korea (Moon et al., 2023) and Brazil (Feitosa et al., 2024). The high resistance of E. coli strains to these antibiotics is not surprising, given their widespread use worldwide in both human and veterinary medicine.

In the current study, doxycycline resistance (26.0%) was higher than the rates of 11.0% and 14.8% reported in similar studies in Canada and South Korea (Leonard et al., 2012; Moon et al., 2023). However, this antibiotic was resistant to 45.19% of the canine-derived E. coli strains with diarrhea in China (Yuan et al., 2024). The isolated E. coli strains showed resistance to gentamicin at a rate of 16.7%, lower than the 28.89% reported in a similar study in China (Yuan et al., 2024). Notably, resistance to this antibiotic was only observed in 0.8 - 8.0% of E. coli strains isolated from dogs and cats in several countries such as Canada (Leonard et al., 2012), the West Indies (Amandi et al., 2019), South Korea (Moon et al., 2023), Peru (Ventura et al., 2024), Germany (Frenzer et al., 2024), and Brazil (Feitosa et al., 2024). The proportion of trimethoprim/

Table 1: Prevalence of E. coli in the fecal samples of dogs and cats at veterinary clinics.

Animal condition	Dog fecal samples			Cat fecal samples			Total
Animal condition	n	Positive n (%)	Negative n (%)	n	Positive n (%)	Negative n (%)	n	Positive n (%)	Negative n (%)
Healthy	50	28 (56.0)	22 (44.0)	38	21 (55.3)	17 (44.7)	88	49 (55.7)	39 (44.3)
Diarrhea	42	27 (64.3)	15 (35.7)	31	20 (64.5)	11 (35.5)	73	47 (64.4)	26 (35.6)
Total	92	55 (59.8)	37 (40.2)	69	41 (59.4)	28 (40.6)	161	96 (59.6)	65 (40.4)

Table 2: Antibiotic resistance of the E. coli strains isolated from dog and cat fecal samples.

Groups/classes	Antibiotics	From healthy dogs and cats n (%)	From diarrhea dogs and cats n (%)	P-value	95% CI	Total n (%)
Penicillin	Ampicillin	22 (44.9)	44 (93.6)	≤0.0001	0.01 - 0.22	66 (68.8)
Cephalosporin	Cefotaxime	14 (28.6)	24 (51.1)	0.0445	0.15 - 0.96	38 (39.6)
Carbapenem	Meropenem	0 (0.0)	4 (8.5)	0.0591	0.00 - 1.41	4 (4.2)
Tetracyclines	Doxycycline	8 (16.3)	17 (36.2)	0.0445	0.11 - 0.99	25 (26.0)
Tetracyclines	Tetracycline	15 (30.6)	31 (66.0)	0.0036	0.09 - 0.58	46 (47.9)
Aminoglycosides	Gentamicin	3 (6.1)	13 (27.7)	0.0128	0.03 - 0.70	16 (16.7)
Aminoglycosides	Streptomycin	27 (55.1)	36 (76.6)	0.0445	0.14 - 0.98	63 (65.6)
Quinolones	Nalidixic acid	3 (6.1)	13 (27.7)	0.0128	0.03 - 0.70	16 (16.7)
Quinolones	Norfloxacin	3 (6.1)	8 (17.0)	0.1168	0.05 - 1.46	11 (11.5)
Sulfonamides	Sulfonamides	16 (32.7)	27 (57.4)	0.0430	0.14 - 0.89	43 (44.8)
Sulfonamides	Trimethoprim/ Sulfamethoxazole	5 (10.2)	26 (55.3)	≤0.0001	0.02 - 0.30	31 (32.3)

E. coli isolated from healthy dogs and cats (n=49); from diarrhea dogs and cats (n=47); and Total (n=96); CI= Confidence Interval.

sulfamethoxazole-resistant E. coli strains (32.3%) was onsistent with those (25.7% and 25.8%), reported in similar studies in Peru (Ventura et al., 2024) and Brazil (Feitosa et al., 2024), respectively. However, these rates are lower than those observed in E. coli strains from diarrheal dogs in China (Yuan et al., 2024), and healthy dogs and cats in Zimbabwe (Matope et al., 2024). In contrast, the E. coli strains showed antibiotic resistance of 5.0% to 12.0%, and 14.6% in the previous studies conducted in West Indies, Germany, and South Korea (Amandi et al., 2019; Moon et al., 2023; Frenzer et al., 2024), respectively. The relatively high resistance rates of E. coli strains to these three antibiotics may be related to their widespread use for treating infections in dogs and cats at veterinary clinics in Vietnam.

Tubes 1-6: The E. coli strains exhibited fermentation and gas production; Tube 7: negative control.

The isolated E. coli strains exhibited resistance to norfloxacin and nalidixic acid at rates of 11.5% and 16.7%, respectively. These rates are lower than those reported in a previous study in Peru (Ventura et al., 2024), which reported resistance rates of 31.4% and 54.3%, respectively. Specifically, norfloxacin resistance rates were identified at 17.3% and 21.9% in E. coli strains originating from dog and cat feces in Thailand (Sattasathuchana et al., 2024) and Poland (Rzewuska et al., 2015). Information and levels of resistance to these antibiotics are crucial because they are primarily used in humans and veterinary medicine (Antimicrobial Resistance Collaborators, 2022). The resistance rate of cefotaxime (39.6%) is consistent with the resistance rate (33.3%) of E. coli isolated from dogs with diarrhea in China (Yuan et al., 2024). However, a lower resistance rate (20.0%) was observed in E. coli isolated from dogs in Peru (Ventura et al., 2024). Notably, none and 1.0% of dog and cat-derived E. coli strains were resistant to this antibiotic in West Indies (Amandi et al., 2019) and European countries (Joosten et al., 2020), respectively. In this study, approximately 4.2% of the isolated E. coli strains were suspected to be meropenem-resistant. However, the determination of meropenem resistance using the agar diffusion method is not recommended by the Clinical Laboratory Standards Institute (CLSI) unless it is a clinical E. coli strain (CLSI, 2020). Therefore, further studies are needed to definitively determine whether these strains are resistant to meropenem by determining the minimum inhibitory concentration (MIC) and/or molecular resistance mechanisms through screening of carbapenemase resistance genes (blaNDM, blaKPC, blaOXA-48, blaIMP, blaVIM). A similar resistance rate of meropenem was observed in the E. coli strains isolated from dogs in Peru (Ventura et al., 2024). However, the E. coli strains exhibited higher resistance rate (10.1%) to meropenem in previous studies in China (Tong et al., 2023). Notably, E. coli strains isolated from cat feces in Thailand exhibited a very low resistance rate to meropenem (Sattasathuchana et al., 2024); and all E. coli strains isolated from dogs and cats in European countries were susceptible to this antibiotic (Joosten et al., 2020). Although the resistance rates of E. coli to carbapenems and cephalosporins remains relatively low, this is still concerning because these are antibiotic classes considered last-resort treatments for human infections.

The E. coli strains isolated from dog and cat feces exhibited various resistance phenotypes to the antibiotics tested. For the isolates obtained from healthy dogs and cats (Table 3), thirteen strains were susceptible to all antibiotics; fifteen strains were resistant to 1-2 antibiotic agents. Meanwhile, resistance to 3-4 and 5-6 antibiotic agents were observed in thirteen and seven strains, respectively; only one of the isolated strains shown resistant to eight antibiotic agents. The E. coli strains exhibited twenty-one antibiotic-resistant phenotypes. The most common resistance phenotype was AMP (five isolates), followed by AMP+CTX+STM+SUL and AMP+STM, detected in four and three out of the isolates, respectively. The remaining resistance phenotypes were determined in from one to two out of the isolated E. coli strains. Among the isolates obtained from dogs and cats with diarrhea (Table 4), only one strain was susceptible to all antibiotics. Five out of the isolated strains were found to be resistant to two antibiotic agents; resistance to 3-4 antibiotic agents and 5-6 antibiotic agents were observed in fifteen and thirteen out of the isolated strains, respectively. Nine out of the isolated strains were found to be resistant to 7-8 antibiotic agents. Notably, resistance to 9 - 10 antibiotic agents was identified in three isolated strains. The E. coli strains were found to possess a total of thirty-six antibiotic resistance patterns. Furthermore, the most common resistance pattern was AMP+STX+DOX+TET+CTX+STM+SUL and AMP+TET+CTX+STM, which was found in three and four out of the isolated strains, respectively. The remaining resistance patterns were usually found in one or two out of the E. coli isolates. The E. coli strains from dogs and cats with

Table 3: Multidrug resistance of the E. coli isolated from fecal samples of healthy dogs and cats (n=49).

Order	Antibiotic resistance patterns (n)	No. of antibiotics	No. of antibiotic classes
1	Susceptible (n=13)	0	0
2	AMP (n=5)	1	1
3	STM (n=2)	1	1
4	TET (n=2)	1	1
5	AMP, STM (n=3)	2	2
6	CTX, SUL (n=1)	2	2
7	STM, SUL (n=2)	2	2
8	AMP, CTX, STM (n=1)	3	3
9	AMP, STM, SUL (n=1)	3	3
10	DOX, TET, STM (n=2)	3	2
11	TET, CTX, STM (n=2)	3	3
12	TET, STM, SUL (n=1)	3	3
13	AMP, CTX, STM, SUL (n=4)	4	3
14	AMP, TET, STM, SUL (n=1)	4	4
15	DOX, TET, CTX, STM (n=1)	4	3
16	AMP, STX, CTX, STM, SUL (n=2)	5	4
17	AMP, STX, TET, GEN, NAL, NOR (n=1)	6	5
18	AMP, DOX, TET, NAL, NOR, STM (n=1)	6	4
19	DOX, TET, GEN, CTX, STM, SUL (n=1)	6	4
20	AMP, STX, DOX, TET, CTX, STM, SUL (n=1)	7	5
21	AMP, STX, DOX, TET, GEN, STM, SUL (n=1)	7	5
22	AMP, DOX, TET, NAL, CTX, NOR, STM, SUL (n=1)	8	6

AMP: Ampicillin; CTX: Cefotaxime; DOX: Doxycycline; GEN: Gentamicin; NAL: Nalidixic acid; NOR: Norfloxacin; STM: Streptomycin; STX: Trimethoprim/Sulfamethoxazole; SUL: Sulfonamides; TET: Tetracycline.

Table 4: Multidrug resistance of the E. coli isolated from fecal samples of diarrhea dogs and cats (n=47).

Order	Antibiotic resistance patterns (n)	No. of antibiotics	No. of antibiotic classes
1	Susceptible (n=1)	0	0
2	AMP, CTX (n=1)	2	2
3	AMP, STM (n=1)	2	2
4	AMP, TET (n=2)	2	2
5	STM, SUL (n=1)	2	2
6	AMP, STX, MEM (n=1)	3	3
7	AMP, CTX, SUL (n=1)	3	3
8	TET, CTX, STM (n=1)	3	3
9	AMP, STX, CTX, SUL (n=1)	4	3
10	AMP, STX, STM, SUL (n=2)	4	3
11	AMP, DOX, TET, STM (n=1)	4	3
12	AMP, NAL, CTX, STM (n=1)	4	4
13	AMP, TET, CTX, STM (n=4)	4	4
14	AMP, TET, STM, SUL (n=3)	4	4
15	AMP, STX, CTX, STM, SUL (n=1)	5	4
16	AMP, STX, DOX, TET, STM (n=1)	5	4
17	AMP, STX, GEN, NAL, SUL (n=1)	5	4
18	AMP, STX, TET, CTX, STM (n=1)	5	5
19	AMP, DOX, TET, CTX, SUL (n=1)	5	4
20	AMP, TET, CTX, STM, SUL (n=1)	5	5
21	STX, DOX, TET, STM, SUL (n=1)	5	4
22	AMP, STX, DOX, TET, GEN, STM (n=2)	6	4
23	AMP, STX, GEN, NAL, CTX, MEM (n=1)	6	6
24	AMP, STX, GEN, NAL, STM, SUL (n=1)	6	5
25	AMP, STX, NAL, NOR, STM, SUL (n=1)	6	4
26	AMP, TET, NAL, NOR, STM, SUL (n=1)	6	5
27	AMP, STX, DOX, TET, CTX, STM, SUL (n=3)	7	5
28	AMP, STX, DOX, TET, GEN, STM, SUL (n=1)	7	5
29	AMP, STX, DOX, TET, STM, MEM, SUL (n=1)	7	6
30	AMP, STX, GEN, NAL, CTX, NOR, STM (n=1)	7	5
31	AMP, STX, DOX, TET, GEN, CTX, STM, SUL (n=1)	8	5
32	AMP, STX, DOX, TET, GEN, NAL, NOR, STM (n=1)	8	5
33	AMP, STX, TET, NAL, CTX, NOR, STM, SUL (n=1)	8	6
34	AMP, STX, DOX, TET, GEN, NAL, CTX, STM, SUL (n=1)	9	6
35	AMP, STX, DOX, TET, GEN, NAL, CTX, NOR, STM, SUL (n=2)	10	6
36	AMP, DOX, TET, GEN, NAL, CTX, NOR, STM, MEM, SUL (n=1)	10	7

AMP: Ampicillin; CTX: Cefotaxime; DOX: Doxycycline; GEN: Gentamicin; MEM: Meropenem; NAL: Nalidixic acid; NOR: Norfloxacin; STM: Streptomycin; STX: Trimethoprim/Sulfamethoxazole; SUL: Sulfonamides; TET: Tetracycline

diarrhea exhibited higher MDR rates as compared to the isolated strains from healthy dogs and cats (87.2% and 38.8%, respectively; p < 0.0001). Resistance to five or six antibiotic groups was found in 36.2% (17/47) and 8.2% (4/49) of the diarrhea and healthy dog and cat isolates, respectively. Only one out of the E. coli strains obtained from diarrhea fecal samples exhibited resistance to seven antibiotic classes.

In the present study, approximately 85.4% of the E. coli strains exhibited resistance to at least one antibiotic (Table 5). Of these, 62.5% of the strains were identified as MDR. These rates were comparable to the previous studies in China (Zhou et al., 2022; Yuan et al., 2024), reported that

Table 5: Number of the E. coli isolates exhibited the MDR.

Order	No. of antibiotic resistance classes	Healthy (n=49)		Diarrhea (n=47)		Total (n=96)
Order	No. of antibiotic resistance classes	n	%	n	%	n	%
1	No resistance	13	26.5	1	2.1	14	14.6
2	Resistance to 1-2 classes	17	34.7	5	10.6	22	22.9
3	Resistance to 3-4 classes	15	30.6	23	48.9	38	39.6
4	Resistance to 5-6 classes	4	8.2	17	36.2	21	21.9
5	Resistance to ≥ 7 classes	0	0.0	1	2.1	1	1.0

the MDR was identified in 54.81-63.7% of the E. coli isolates. Furthermore, another previous study in China documented that 72.25% of the E. coli isolated from dogs as MDR strains (Tong et al., 2023). Nevertheless, MDR rates were determined in 13.3-14.5%, 18.0%, and 20.9- 34.9% of the E. coli strains in previous studies in South Korean (Moon et al., 2023), Zimbabwe (Matope et al., 2024) and Canada (Awosile et al., 2018), respectively. The detection of multidrug-resistance isolates is serious concern and requires attention (Bourne et al., 2019; Tong et al., 2023). These multidrug-resistant bacterial strains can pose significant challenges to antibiotic therapy in livestock, such as complicating antibiotic selection, reducing treatment efficacy, and increasing veterinary service costs (Awosile et al., 2018; Zhou et al., 2022). Therefore, raising awareness of antibiotic resistance transmission in humans, animals, and the environment is crucial (Poirel et al., 2018; Feitosa et al., 2024; Yuan et al., 2024). Antibiotic resistance can also be controlled by providing education to raise public awareness and understanding of antibiotic resistance, aiming to changing people’s behaviour towards rational antibiotic use and good environmental hygiene practices (Stålsby Lundborg and Tamhankar, 2014; Ahmed et al., 2024).

CONCLUSIONS

In summary, this study shows that the majority of isolated E. coli strains were resistant to at least one antibiotic, with various resistance patterns observed in the isolates. Notably, multidrug-resistant E. coli strains were more commonly found in fecal samples from dogs and cats with diarrhea compared to strains from healthy dogs and cats. These results suggest that veterinary clinics in Hanoi city need to use antibiotics correctly, following manufacturer guidelines and legal regulations to limit antibiotic resistance and the spread of antibiotic-resistant bacterial strains. Furthermore, further molecular studies are needed to identify pathogenic and antibiotic resistance genes in the isolated bacterial strains.

ACKNOWLEDGEMENTS

The authors would like to thank the students for transporting samples and the local veterinarian for their excellent technical assistance.

NOVELTY STATEMENT

This study provides information on the prevalence of E. coli in fecal samples from dogs and cats collected from veterinary clinics in Hanoi, Vietnam. The results indicated that the isolated E. coli strains were resistant to many antibiotics, including important ones such as cefotaxime and meropenem, which are used in human medicine. Furthermore, information on the antibiotic resistance of bacteria helps raise awareness of the safe and prudent use of antibiotics in animal husbandry and veterinary medicine.

Author’s Contribution

CTTH: study design, investigation and methodology, and manuscript writing. NVP, TLO, NMT: experimentation and data analysis. NVG and NHT: laboratory research design, sample testing supervision, and manuscript editing. THT: conceptualization, supervision, writing, review and editing, project management.

Funding information

The present study received no external funding. The authors contributed to this study independently.

Ethics approval

The present study was conducted by collecting samples in accordance with the guidelines outlined in the Helsinki declaration and the animal welfare and safety procedures of the Committee on Animal Research and Ethics (CARE), Faculty of Veterinary Medicine, Vietnam National University of Agriculture, Vietnam (Approval No. CARE-2024/06).

Generative AI and AI assisted technology statement

AI-generated tools were not used to create any scientific content. Any AI assistance was limited to minor language editing, and all ideas, interpretations, and conclusions remain entirely the authors.

Statement of conflict of interest

The authors have declared no conflict of interest.

REFERENCES

Ahmed SK, Hussein S, Qurbani K, Ibrahim RH, Fareeq A, Mahmood KA, Mohamed MG (2024). Antimicrobial resistance: Impacts, challenges, and future prospects. J. Med. Surg. Publ. Health., (2): 100081. https://doi.org/10.1016/j.jgar.2024.10.068

Amadi VA, Hariharan H, Amadi OA, Matthew-Belmar V, Nicholas-Thomas R, Perea ML, Carter K, Rennie E, Kalasi K, Alhassan A, Kabuusu RM, Alozie GU, Fields PJ, Pinckney R, Sharma R (2019). Antimicrobial resistance patterns of commensal Escherichia coli isolated from feces of non-diarrheic dogs in Grenada, West Indies. Vet. World, 12(12): 2070-2075. https://doi.org/10.14202/vetworld.2019.2070-2075

Antimicrobial Resistance Collaborators (2022). Global burden of bacterial antimicrobial resistance in 2019: A systematic analysis. Lancet, 399(10325): 629-655.

Awosile BB, McClure JT; Saab ME, Heider LC (2018). Antimicrobial resistance in bacteria isolated from cats and dogs from the Atlantic provinces, Canada from 1994-2013. Can. Vet. J., 59(8): 885-893. Available at: https://pmc.ncbi.nlm.nih.gov/articles/PMC6049328/

Bauer AW, Kirby WM, Sherris JC, Turck M (1966). Antibiotic susceptibility testing by a standardized single disk method. Am. J. Clin. Pathol., 45(4): 493-96. Available at: https://academic.oup.com/ajcp/article-abstract/45/4_ts/493/4821085?redirectedFrom=fulltext https://doi.org/10.1093/ajcp/45.4_ts.493

Bourne JA, Chong WL, Gordon DM (2019). Genetic structure, antimicrobial resistance and frequency of human associated Escherichia coli sequence types among faecal isolates from healthy dogs and cats living in Canberra, Australia. PLoS One, 14(3): e0212867.

Carvalho I, Carvalho JA, Martinez-Alvarez S, Sadi M, Capita R, Alonso-Calleja C, Rabbi F, Dapkevicius MLN, Igrejas G, Torres C, Poeta P (2021). Characterization of ESBL-producing Escherichia coli and Klebsiella pneumoniae isolated from clinical samples in a Northern Portuguese hospital: Predominance of CTX-M-15 and high genetic diversity. Microorganisms, 9(9): 1914. https://doi.org/10.3390/microorganisms9091914

CLSI (2020). Performance standards for antimicrobial susceptibility testing, 30th Edition. CLSI supplement M100. Wayne, PA, USA: Clinical and Laboratory Standards Institute; pp. 32-41. Available at: https://www.nih.org.pk/wp-content/uploads/2021/02/CLSI-2020.pdf

Cummins EA, Snaith AE, McNally A, Hall RJ (2021). The role of potentiating mutations in the evolution of pandemic Escherichia coli clones. Eur. J. Clin. Microbiol. Infect. Dis., Epub ahead of print. https://doi.org/10.1007/s10096-021-04359-3

Derakhshandeh A, Eraghi V, Boroojeni, AM, Niaki MA, Zare S, Naziri Z (2018). Virulence factors, antibiotic resistance genes and genetic relatedness of commensal Escherichia coli isolates from dogs and their owners. Microb. Pathog., 116: 241-245. https://doi.org/10.1016/j.micpath.2018.01.041

Feitosa CB, dos Santos GS, Gaeta NC, Schiavi GdS, Vasconcelos CGC, Filho JM, Heinemann MB, Cortez A (2024). Enteropathogenic and multi-drug resistant blaCTX-M-carrying E. coli isolates from dogs and cats. Animals (Basels), 14(17): 2463. https://doi.org/10.3390/ani14172463

Frenzer SK, Feuer L, Bartel A, Bethe A, Lübke-Becker A, Klein B, Bäumer W, Merle R (2024). Third generation cephalosporin resistant Escherichia coli in dogs and cats in Germany in 2019–2021. PLoS One, 19(8): e0309554. https://doi.org/10.1371/journal.pone.0309554

Guardabassi L, Schwarz S, Lloyd DH (2004). Pet animals as reservoirs of antimicrobial-resistant bacteria. J. Antimicrob. Chemother., 54(2): 321-332. https://doi.org/10.1093/jac/dkh332

Joosten P, Ceccarelli D, Odent E, Sarrazin S, Graveland H, Van Gompel L, Battisti A, Caprioli A, Franco A, Wagenaar JA, Mevius D, Dewulf J (2020). Antimicrobial usage and resistance in companion animals: A cross-sectional study in three European countries. Antibiotics (Basel), 9(2): 87. https://doi.org/10.3390/antibiotics9020087

Leonard EK, Pearl DL, Finley RL, Janecko N, Reid-Smith RJ, Peregrine AS, Weese JS (2012). Comparison of antimicrobial resistance patterns of Salmonella spp. and Escherichia coli recovered from pet dogs in volunteer households in Ontario (2005-06). J. Antimicrob. Chemother., 67(1): 174-181. https://doi.org/10.1093/jac/dkr430

Magiorakos AP, Srinivasan A, Carey RB, Carmeli Y, Falagas ME, Giske CG, Harbarth S, Hindler JF, Kahlmeter G, Olsson-Liljequist B, Paterson DL, Rice LB, Stelling J, Struelens MJ, Vatopoulos A, Weber JT, Monnet DL (2012). Multidrug-resistant, extensively drug-resistant and pandrug-resistant bacteria: An international expert proposal for interim standard definitions for acquired resistance. Clin. Microbiol. Infec., 18(3): 268-281. https://doi.org/10.1111/j.1469-0691.2011.03570.x

Marchetti L, Buldain D, Gortari Castillo L, Buchamer A, Chirino-Trejo M, Mestorino N (2021). Pet and stray dogs as reservoirs of antimicrobial-resistant Escherichia coli. Int. J. Microbiol., 2021: 6664557. https://doi.org/10.1155/2021/6664557

Matope G, Chaima K, Bande B, Bare W, Kadzviti F, Jinjika F, Tivapasi M (2024). Isolation of multi-drug resistant strains of Escherichia coli from faecal samples of dogs and cats from Harare, Zimbabwe. Vet. Med. Sci., 10(4): e1472. https://doi.org/10.1002/vms3.1472

Ministry of Agriculture and Rural Development (MARD). 2011. National technical regulation on animal diseases - General requirements for sample collection, storage and shipment. QCVN 01-83:2011/BNNPTNT, pp: 5–10. promulgated under Circular No. 71/2011/TT-BNNPTNT of MARD. Available at https://sgtvt.bacninh.gov.vn/documents/154127/14279228/QCVN+01-83-2011-BNNPTNT.pdf/2a692d85-15d0-445c-969e-8964f5dadcad

Moon BY, Ali MS, Kwon DH, Heo YE, Hwang YJ, Kim JI, Lee YJ, Yoon SS, Moon DC, Lim SK (2023). Antimicrobial resistance in Escherichia coli isolated from healthy dogs and cats in South Korea, 2020-2022. Antibiotics (Basel), 13(1): 27. https://doi.org/10.3390/antibiotics13010027

Mustapha M, Audu Y, Ezema KU, Abdulkadir JU, Lawal JR, Balami AG, Adamu L, Bukar-Kolo YM (2021). Antimicrobial susceptibility profiles of Escherichia coli isolates from diarrheic dogs in Maiduguri, Borno state, Nigeria. Mac. Vet. Rev., 44(1): 47-53. https://doi.org/10.2478/macvetrev-2020-0035

Nugroho WS, Karmo AD, Silalahi GE, Kajang EA, Gallantiswara PCD (2024). Cross-sectional study of antibiotic resistance to Escherichia coli and Salmonella spp. in cats in Yogyakarta, Indonesia, and Dili, Timor-Leste. Vet. World., 17(10): 2347-2354. https://doi.org/10.14202/vetworld.2024.2347-2354

Poirel L, Madec JY, Lupo A, Schink AK, Kieffer N, Nordmann P, Schwarz S (2018). Antimicrobial resistance in Escherichia coli. Microbiol. Spectr., 6(4): 10.1128. https://doi.org/10.1128/microbiolspec.ARBA-0026-2017

Ramos CP, Kamei CYI, Viegas FM, de Melo Barbieri J, Cunha JLR, Hounmanou YMG, Coura FM, Santana JA, Lobato FCF, Bojesen AM, Silva ROS (2022). Fecal shedding of multidrug resistant Escherichia coli isolates in dogs fed with raw meat - Based diets in Brazil. Antibiotics (Basel)., 11(4): 534. https://doi.org/10.3390/antibiotics11040534

Rzewuska M, Czopowicz M, Kizerwetter-Świda M, Chrobak D, Błaszczak B, Binek M (2015). Multidrug resistance in Escherichia coli strains isolated from infections in dogs and cats in Poland (2007-2013). Sci. World J., 2015: 408205. https://doi.org/10.1155/2015/408205

Sattasathuchana P, Srikullabutr S, Kerdsin A, Assawarachan SN, Amavisit P, Surachetpong W, Thengchaisri N (2024). Antimicrobial resistance of Escherichia coli in cats and their drinking water: Drug resistance profiles and antimicrobial-resistant genes. BMC Vet. Res., 20(1): 573. https://doi.org/10.1186/s12917-024-04435-8

Stålsby Lundborg C and Tamhankar AJ (2014). Understanding and changing human behaviour-antibiotic mainstreaming as an approach to facilitate modification of provider and consumer behaviour. UPS J. Med. Sci., 119(2): 125-133. https://doi.org/10.3109/03009734.2014.905664

Tong YC, Zhang YN, Li PC, Cao YL, Ding DZ, Yang Y, Lin QY, Gao YN, Sun SQ, Fan YP, Liu YQ, Qing SZ, Ma WR, Zhang WM (2023). Detection of antibiotic-resistant canine origin Escherichia coli and the synergistic effect of magnolol in reducing the resistance of multidrug-resistant Escherichia coli. Front Vet Sci., 10:1104812. doi:10.3389/fvets.2023.1104812

Ventura M, Oporto-Llerena R, Espinoza K, Guibert F, Quispe AM, Vilar N, López M, Rojo-Bezares B, Sáenz Y, Ruiz J, Pons MJ (2024). Antimicrobial resistance and associated risk factors in Escherichia coli isolated from Peruvian dogs: A focus on extended-spectrum β-lactamases and colistin. Vet. World, 17(4): 880-887. https://doi.org/10.14202/vetworld.2024.880-887

Wu Y, Fan R, Wang Y, Lei L, Fessler AT, Wang Z, Wu C, Schwarz S, Wang Y (2019). Analysis of combined resistance to oxazolidinones and phenicols among bacteria from dogs fed with raw meat/vegetables and the respective food items. Sci. Rep., 9(1): 15500. https://doi.org/10.1038/s41598-019-51918-y

Yuan Y, Hu Y, Zhang X, Zhong W, Pan S, Wang L, Zhou Z, Liu H, Zhang S, Peng G, Wang Y, Yan Q, Luo Y, Shi K, Zhong Z (2024). Characteristics of MDR E. coli strains isolated from pet dogs with clinic diarrhea: A pool of antibiotic resistance genes and virulence-associated genes. PLoS One, 19(2): e0298053. https://doi.org/10.1371/journal.pone.0298053

Zhou Y, Ji X, Liang B, Jiang B, Li Y, Yuan T, Zhu L, Liu J, Guo X, Sun Y (2022). Antimicrobial resistance and prevalence of extended spectrum β-lactamase-producing Escherichia coli from dogs and cats in Northeastern China from 2012 to 2021. Antibiotics (Basel), 11(11): 1506. https://doi.org/10.3390/antibiotics11111506