Celery (Apium graveolens L.), coriander (Coriandrum sativum L.) and parsley (Petroselinum crispum) were purchased from a commercial market in Alexandria, Egypt, and their aerial parts were extracted separately with methanol. Each methanolic extract was then partitioned into a methylene chloride fraction and an aqueous mother liquor. The biological tests used 20 uropathogenic E. coli isolates obtained from private laboratories in Alexandria. Susceptibility testing showed that every isolate was resistant to amoxicillin-clavulanic acid, doxycycline and nalidixic acid, while all were susceptible to ertapenem, imipenem and meropenem. Twelve isolates were classified as strong biofilm formers, four as intermediate formers and four as non-biofilm formers.

The antibacterial results varied markedly among the herbs and fractions. Coriander’s total methanolic extract and aqueous mother liquor each produced a minimum inhibitory concentration of 3.75 micrograms per millilitre, the lowest value reported for the plant preparations. Its methylene chloride fraction required 100 micrograms per millilitre. Celery was less active: the total methanolic extract had a minimum inhibitory concentration of 50 micrograms per millilitre, while its aqueous mother liquor reached 25 micrograms per millilitre and its methylene chloride fraction showed no detectable activity under the tested conditions. Parsley’s total extract and aqueous mother liquor likewise had no detectable activity, although its methylene chloride fraction inhibited growth at 100 micrograms per millilitre. Ciprofloxacin and norfloxacin had minimum inhibitory concentrations between 0.9 and 1.9 micrograms per millilitre alone. When combined with coriander extract, the effects were described as additive, with no evidence of synergism or antagonism in the tested combinations.

Untargeted metabolomics produced markedly different profiles for the three herbs. Analyses were run in positive and negative electrospray ionization modes and incorporated retention time, accurate mass, predicted molecular formulas and tandem mass-spectrometry fragmentation patterns. Compound detection and processing initially yielded 4,861 features in negative mode and 3,155 in positive mode; after peak detection, deisotoping, chromatographic alignment and filtering, 580 and 512 aligned features, respectively, remained for chemometric analysis. The final annotation included flavonoids and glycosides, isoflavones, phenolic acids, coumarins, amino-acid derivatives, fatty acids and lipids, chlorins and a lignan. All 167 annotations were assigned level 2 confidence, meaning they were tentative identifications supported by library or literature spectral matches rather than confirmed with authentic standards.

Coriander had the richest and most diverse flavonoid and phenolic profile in this analysis. Its extracts contained quercetin, multiple quercetin conjugates, apigenin glucuronide, luteolin-7-O-glucoside, kaempferol-3-O-glucorhamnoside, several caffeoylquinic-acid derivatives, ferulic acid and assorted coumarins. Celery was distinguished by compounds including apiin, luteolin and apigenin conjugates, 4,5-dicaffeoylquinic acid and the coumarin marmesin. Parsley contained numerous furanocoumarins, including cnidilin, 5-hydroxyxanthotoxin, pinnatin, bergaptol and isoimperatorin, as well as rhamnetin and isorhamnetin conjugates. The researchers also detected chlorin-related molecules in all three herbs and the lignan eucommicin A in celery and coriander.

Principal component analysis, hierarchical cluster analysis and partial least squares discriminant analysis separated the three samples according to their metabolite profiles. In negative-ion mode, the first two principal components accounted for 95% of the observed variability, and the samples formed three distinct clusters. Coriander was associated with high levels of quercetin 3-O-rutinoside, eucommicin A and several hydroxylated C18 fatty acids, including three trihydroxy-octadecaenoic-acid features and hydroxy-octadecatrienoic- and hydroxy-octadecadienoic-acid features. Celery was associated with apiin, luteolin 7-O-apiosylglucoside, pyroglutamic acid, lunularic acid and a glycerophosphoinositol. Parsley was distinguished by fructose-phenylalanine and features including bergaptol. Supervised models separating celery from parsley reported R² and Q² values of 0.99 in both ionization modes, although the limited set of triplicate samples means these internal performance values should not be confused with independent validation.

Partial least squares regression then related metabolite abundance to the measured minimum inhibitory concentrations. The negative-ion model had cumulative R² of 0.92 and Q² of 0.87, while the positive-ion model had R² of 0.94 and Q² of 0.83. In both models, coriander’s metabolite pattern was inversely positioned relative to minimum inhibitory concentration, whereas parsley lay closest to the values associated with inactivity. Prominent variables associated with antibacterial activity included quercetin 3-O-rutinoside, trihydroxy-octadecaenoic-acid isomers, hydroxy-octadecatrienoic acid, hydroxy-octadecadienoic acid and eucommicin A. Positive-ion analysis additionally highlighted furanocoumarin hexosides, a methoxy-ethoxycarbonyl coumarin and a chlorin-related compound, 132-hydroxypheophorbide-A methyl ester. These are statistical associations within extract-level data, not demonstrations that any individual metabolite caused the observed inhibition.

All tested plant preparations also inhibited biofilm formation, whether used alone or in combinations with ciprofloxacin or norfloxacin. Biofilm mass was measured after 24 hours by fixing the attached biomass with methanol, staining it with crystal violet, releasing the dye with acetic acid and measuring absorbance at 630 nanometres. The study reported significant reductions in biofilm mass across the extract and antibiotic-combination conditions, including tests with sub-minimum-inhibitory-concentration levels of the plant extracts. The researchers discussed several possible contributors, including quercetin derivatives, phenolic compounds and coumarins that have activity against cell membranes, quorum sensing, extracellular polymeric substances and other biofilm-maintenance processes in earlier studies. Those mechanisms remain hypotheses for the herb extracts tested here, which were not separated into constituent compounds during the assays.

The bacterial collection also displayed several virulence-associated genes, adding context to the laboratory model. The fimH gene was present in 80% of the isolates, afa genes in 90%, papC in 76% and hly genes in 76%; the cytotoxic necrotizing factor gene occurred in 35%. These findings characterize the tested isolates but do not show that the herbal preparations affect the corresponding virulence traits. Moreover, the experiments were performed in vitro with commercial plant material, methanol-derived fractions and an artificial biofilm assay. They did not examine pharmacokinetics, host toxicity, urinary concentrations, treatment outcomes or the possibility of interactions with conventional drugs in patients.

For that reason, the results are best understood as a chemical and activity map for future research. The strongest candidates identified for isolation include quercetin 3-O-rutinoside, trihydroxy-octadecaenoic acid, hydroxy-octadecatrienoic acid, hydroxy-octadecadienoic acid and eucommicin A, together with selected coumarins and chlorin-related metabolites. The authors propose purifying these compounds, confirming their structures with authentic standards and complementary analytical methods, and testing them individually and in combinations against multidrug-resistant uropathogenic E. coli. Mechanistic work, cytotoxicity and selectivity assessments, and testing in appropriate in-vivo urinary tract infection models would still be required before any therapeutic or preventive application could be considered.

Subject of Research: Metabolite profiles associated with antibacterial and antibiofilm activity of celery, coriander and parsley against multidrug-resistant uropathogenic E. coli

Article Title: Integrative metabolomics and chemometric analysis reveal metabolites associated with antibacterial and antibiofilm activities of celery, Coriander, and parsley against multidrug-resistant uropathogenic Escherichia coli

Article References: Abdel-dayem, S. I. A., El Gedaily, R. A., Eltanany, B. M., Seiffein, N. L., Hani, G. A., Afifi, S. M., & Ali, D. E. (2026). Integrative metabolomics and chemometric analysis reveal metabolites associated with antibacterial and antibiofilm activities of celery, Coriander, and parsley against multidrug-resistant uropathogenic Escherichia coli. BMC Complementary Medicine and Therapies, 26(1), Article 313. https://doi.org/10.1186/s12906-026-05610-0

Image Credits: AI Generated

DOI: 10.1186/s12906-026-05610-0

Keywords: Uropathogenic E. coli, Multidrug resistance, Antibiofilm activity, Coriander, Metabolomics, Plant extracts, Quercetin, Fatty acids, Urinary tract infections, Integrative, chemometric, analysis

Urinary tract infections are among the most frequently diagnosed infectious diseases in dogs, and uropathogenic E. coli, commonly abbreviated UPEC, causes the majority of these infections in both humans and animals. UPEC belongs to the broader family of extraintestinal pathogenic E. coli, or ExPEC, a group of strains that also includes avian pathogenic and sepsis-associated subpathotypes. What distinguishes UPEC is a toolkit of virulence factors that allows the bacterium to colonise and proliferate on the epithelial cells lining the bladder. Chief among these are fimbrial adhesins, particularly Type 1 fimbriae, extracellular protein appendages that anchor the bacteria to bladder cells and initiate infection.

The defining feature of the isolates in this study was their haemolytic activity, the ability to lyse red blood cells on sheep blood agar. That trait is driven by alpha-haemolysin, encoded by the hlyCABD operon. Alpha-haemolysin is a pore-forming toxin that inserts itself into target cell membranes, creating transmembrane pores whose dimensions and conductance properties have been fully characterised through decades of biochemical and structural work. The loss of membrane integrity causes the target cell to burst. In human medicine, roughly half of all UPEC strains carry the hlyA gene, but that proportion climbs with disease severity, reaching up to 78 percent in cases of pyelonephritis, a serious infection of the kidney. Previous work in companion animals has also linked hlyA genes to urinary infections in dogs and cats.

The Vienna team collected isolates from 32 dogs and 19 cats, most of which presented with cystitis, haematuria or dysuria. After recultivating the bacteria on 5 percent sheep blood agar, the researchers extracted DNA and deployed a custom-made DNA microarray platform to screen for a wide panel of virulence-associated genes. They also phylotyped the isolates using the quadruplex Clermont assignment method, determined clonal groups through two-locus CH-clonotyping based on the fumC and fimH sequences, and performed antimicrobial susceptibility testing by agar disc diffusion against fourteen antibiotic agents, following Clinical and Laboratory Standards Institute protocols.

The genetic picture that emerged was strikingly uniform. Fifty of the 51 isolates belonged to phylogenetic group B2, the lineage most commonly associated with extraintestinal pathogenic E. coli in both humans and animals; only a single isolate fell into group B1. Every single isolate carried both fimH, the adhesion gene regarded as a major UPEC virulence marker, and hlyA, the haemolysin gene. Nearly all isolates, 50 of 51, also carried cnf1, a toxin-encoding gene that codes for cytotoxic necrotising factor 1. Additional virulence factors appeared frequently but not universally: pic, which encodes a serine protease, was found in 15 isolates, while papC, part of the P-fimbriae apparatus, and iucD, an aerobactin synthesis gene found only in virulent strains, each appeared in 11 isolates, always occurring together.

The authors note that while the predominance of phylogroup B2 was expected, the complete conservation of the cnf1 and hlyA linkage within this geographic cohort offers novel insight into the regional clonal stability of UPEC in Austrian companion animals. Clonotyping differentiated 34 distinct CH clonotypes, with CH103-9 the most prevalent, accounting for seven isolates. Several other clonotypes appeared in pairs, suggesting limited clonal relatedness among the sampled animals. Notably, most of the detected clonotypes correspond to clonal complexes previously reported in UPEC studies elsewhere, including CC73, CC12, CC127, CC141 and CC372, the last of which has been primarily associated with dogs rather than humans.

Antimicrobial resistance proved to be rare. Forty-five of the 51 isolates, or about 88 percent, were susceptible to every antibiotic tested, a reassuring result for clinicians managing urinary infections in pets. Resistance, where it occurred, was well explained by the genotype. Detected resistance genes including blaTEM, blaOXA-2, sul1, sul2, dfrA1, dfrA5, tet(A), aac(3′)-IVa and catA matched the phenotypic findings, and four isolates displayed multidrug-resistant profiles.

One isolate, however, stood out as a cause for vigilance. This strain carried an extended-spectrum beta-lactamase phenotype and was resistant to beta-lactams, ciprofloxacin, tetracycline, gentamicin and fosfomycin. Sequencing of the quinolone resistance-determining regions revealed classic amino acid substitutions in gyrA and parC that explain the fluoroquinolone resistance. Genotypically, the isolate proved to belong to phylogroup B2, serogroup O25b, sequence type ST131 and clonotype CH40-30, and it carried both blaCTX-M-15 and blaOXA-2. The B2-O25b-ST131 clone is recognised as a major human-associated high-risk pandemic pathogen responsible for a wide range of infections worldwide. Its sporadic detection in Austrian animals, from wildlife, canine prostate tissue, porcine intestinal samples and most recently a faecal sample, had been documented before, but this is a noteworthy addition from a companion animal with a urinary infection.

The study has limitations the authors acknowledge candidly. By restricting the analysis to haemolytic isolates, the work introduces selection bias, and the virulence and resistance potential of non-haemolytic strains causing urinary infections remains to be investigated. The virulence gene panel, while extensive, was finite, and the researchers suggest that whole-genome sequencing of a larger strain collection would provide an even more comprehensive characterisation. The low number of resistant isolates also limits broader epidemiological conclusions about antimicrobial resistance in canine and feline urinary infections.

Nevertheless, the clinical message is broadly positive. The data indicate that a significant proportion of E. coli urinary tract infections in companion animals can still be successfully managed with existing antibiotic therapies. At the same time, the virulence potential of these strains poses a relevant concern for both public and animal health, and the risk of human infection or colonisation from pet-associated isolates has yet to be fully determined. The existence of multidrug-resistant strains in pets with zoonotic potential, exemplified by the ST131 finding, underscores, in the authors’ view, the critical need for a continuous One Health approach to monitor and control the virulence and antimicrobial resistance of E. coli at the interface between animals and people.

Subject of Research: Characterisation of haemolytic uropathogenic Escherichia coli isolated from dogs and cats with urinary tract infections

Article Title: Characterisation of Haemolytic Uropathogenic Escherichia coli Isolated From Dogs and Cats

Article References: Büttner, S., Spergser, J., Makarova, O., Szostak, M. P., Rosel, A. C., Ruppitsch, W., Schäfer‐Somi, S., Müller, E., Braun, S. D., Monecke, S., Ehricht, R., Künzel, F., & Loncaric, I. (2026). Characterisation of Haemolytic Uropathogenic Escherichia coli Isolated From Dogs and Cats. Veterinary Medicine and Science, 12(5), Article e71200. https://doi.org/10.1002/vms3.71200

Image Credits: AI Generated

DOI: 10.1002/vms3.71200

Keywords: uropathogenic E. coli, dogs, cats, urinary tract infections, alpha-haemolysin, virulence genes, phylogroup B2, ST131, antimicrobial resistance, ESBL, One Health, veterinary microbiology