Aeromonas hydrophila RIT668 and Citrobacter portucalensis RIT669—Potential Zoonotic Pathogens Isolated from Spotted Turtles

Abstract

Antimicrobial resistance (AMR) is one of the biggest challenges of the 21st century, and biofilm formation enables bacteria to resist antibiotic at much higher concentrations than planktonic cells. Earlier, we showed that the Gram-negative Aeromonas hydrophila RIT668 and Citrobacter portucalensis RIT669 (closely related to C. freundii NBRC 12681) from infected spotted turtles (Clemmys guttata), formed biofilms and upregulated toxin expression on plastic surfaces, and were predicted to possess multiple antibiotic resistance genes. Here, we show that they each resist several antibiotics in the planktonic phase, but were susceptible to neomycin, and high concentrations of tetracycline and cotrimoxazole. The susceptibility of their biofilms to neomycin and cotrimoxazole was tested using the Calgary device. For A. hydrophila, the minimum inhibitory concentration (MIC) = 500–1000, and the minimum biofilm eradication concentration (MBEC) > 1000 μg/mL, using cotrimoxazole, and MIC = 32.3–62.5, and MBEC > 1000 μg/mL, using neomycin. For C. freundii MIC = 7.8–15.6, and, MBEC > 1000 μg/mL, using cotrimoxazole, and MIC = 7.8, and MBEC > 1000 μg/mL, using neomycin. Both A. hydrophila and C. portucalensis activated an acyl homoserine lactone (AHL) dependent biosensor, suggesting that quorum sensing could mediate biofilm formation. Their multidrug resistance in the planktonic form, and weak biofilm eradication even with neomycin and cotrimoxazole, indicate that A. hydrophila and C. portucalensis are potential zoonotic pathogens, with risks for patients living with implants.

Detection and antimicrobial resistance of Enterobacteriaceae other than Escherichia coli in raccoons from the Madrid region of Spain

“…Regardless of the clinical importance of the species identified, the high frequency of antimicrobial resistance detected was significant. Our results agree with other studies that also found high levels of resistance to β-lactams in Enterobacteriaceae other than E. coli ( 5 , 13 ), including the bacterial species identified in this study ( 1 , 8 , 10 , 16 , 19 , 20 , 22 ). The antimicrobial resistance found in most of the bacterial species isolated in this study is of concern, as the species can act as a reservoir for the spread of antimicrobial resistance to a particular preparation to other microbial inhabitants of the gut community of these animals or even other bacterial pathogens.…”

Emergence of an Extensive Drug Resistant Citrobacter portucalensis Clinical Strain Harboring blaSFO-1, blaKPC-2, and blaNDM-1

“…Since its first report in 2017, diverse occurrences of C. portucalensis in wastewater, sputum, stool, sludge, poultry and, sea turtles across multiple countries have been discovered. [1][2][3][4][5][6] In 2021, Chinese researcher Cao et al isolated C. portucalensis carrying bla NDM-1 from clinical specimens for the first time. 2 Subsequently, in 2022, the coexistence of bla KPC-2 and bla NDM-1 was reported in an extensively drug-resistant C. portucalensis obtained from a hospital in China.…”

Emergence of Extensively Drug-Resistant ST170 Citrobacter portucalensis with Plasmids pK218-KPC, pK218-NDM, and pK218-SHV from a Tertiary Hospital, China

“…In 2019, a genome-wide analysis of C. portucalensis strain NR-12 of poultry origin in Bangladesh was performed and extensive antimicrobial resistance genes (including bla CMY-39 and bla TEM-176 ) and related mobile genetic elements (MGEs) were identified ( 3 ). In 2020, scanning electron micrographs of the C. portucalensis strain RIT669 were obtained, and its antibiotic resistance profile was reported ( 4 ). In particular, in 2021, a clinically isolated carbapenems-resistant C. portucalensis strain 3839 was reported in China.…”