Campylobacter jejuni remains a leading cause of foodborne gastroenteritis worldwide, yet the epidemiological role of wild birds as reservoirs remains poorly understood. This study investigated the genetic diversity, transmission dynamics, and virulome architecture of 396 C. jejuni isolates collected in Croatia (2021–2025) from human, yellow-legged gull, broiler, bovine, and turkey sources. Whole-genome sequencing revealed high genomic diversity (SI>0.88), encompassing 124 sequence types across 25 clonal complexes. While classical MLST clustered 17.01% (n = 25/147, 95% CI: 11.83–23.82%) of gull isolates with human-associated lineages, high-resolution cg/wgMLST refined this overlap, segregating the majority of yellow-legged gull strains into a distinct, host-adapted ST-1275 clade (51.02%, n = 75/147). Furthermore, cg/wgMLST identified shared multi-host genotypes, such as CT6518 (ST-353) and CT3006 (ST-443), across wild gulls, domestic livestock, and clinical human cases. Virulome screening revealed a conserved pathogenic core alongside a lineage-specific periphery; the Guillain-Barré-syndrome-associated wlaN gene showed strong restriction to the dominant ST-21 generalist lineage, whereas the Type IV Secretion System was exceptionally rare (<1.5%). These findings demonstrate that, while most yellow-legged gull isolates constitute host-adapted lineages, gulls also harbor overlapping genotypes shared with livestock and clinical human isolates (6.80%, 95% CI: 3.69–12.18%), compatible with shared ecological niches and common contamination sources rather than direct bird-to-human transmission. This highlights their role as environmental sentinels and potential bridge reservoirs within One Health transmission interfaces. This study provides an indispensable baseline for integrated One Health biosecurity and surveillance strategies that bring together poultry production, ecosystem management, and public health infrastructure.

BackgroundPathogenic strains of Escherichia coli (E. coli) cause colibacillosis in pre- and post-weaning piglets. Fimbrial and non-fimbrial adhesins, as well as heat-labile and heat-stable enterotoxins, are main virulence factors in enterotoxigenic (ETEC), enteroaggregative (EAEC), enteropathogenic (EPEC) and shigatoxigenic (STEC) pathotypes which cause colidiarrhea or colitoxemia in piglets.MethodsFifty-five piglets submitted for necropsy were examined for gross and histological lesions. E. coli strains were isolated, biochemically confirmed, and tested by PCR for 15 virulence genes (VGs). Statistical analyses used appropriate parametric or non-parametric tests, depending on the distribution. The results with p values less than or equal to 0.05 (p ≤ 0.05) were considered statistically significant.ResultsOverall, 84.48% of strains carried at least one VG. The occurrence of six VGs - astA, estII, faeG, estI, elt, and paa - was high, with frequencies of 67.24%, 63.97%, 55.18%, 50.00%, 48.27%, and 44.82%, respectively. ETEC predominated (63.79%), while 5.17% of strains carried EPEC or STEC genes; 15.52% were non-specific virotypes, and 15.52% were apathogenic. Lesions were most prominent in the small intestine. The virotype LT:STa:STb:EAST1:PAA:F4 was most common, whereas STa:Stx2:Stx2e was linked to the most severe lesions. Lesions varied depending on the pathotype involved and the VGs expressed. Severity of lesions differed significantly between suckling and weaned piglets (p = 0.0091) and between piglets with and without diarrhea (p = 0.0223), with suckling and diarrheic piglets showing more pronounced pathological changes. More extensive lesions in ETEC were associated with the acquired astA and paa genes. Pathoscores were significantly associated with faeG/F4 (p = 0.0001), eltA/LT (p = 0.0001), estII/STb (p = 0.0001), paa/PAA (p = 0.0002), and astA/EAST1 (p = 0.0029).Discussion and conclusionsStrong associations between specific VGs - particularly faeG, eltA, estII, paa, and astA - and higher lesion scores show that VG detection can help predict disease severity and guide interventions. Age-specific interpretation is crucial, as isolates from pre-weaned piglets often carried more VGs and were associated with more severe lesions. This study underscores the value of integrating bacteriological, molecular and histopathological data for accurate diagnosis, especially given the high prevalence of VG-positive and recombinant ETEC strains.

BACKGROUND/OBJECTIVES:Non-tuberculous mycobacteria (NTM) are increasingly recognized as important opportunistic pathogens at the human-animal-environment interface. Their growing relevance is driven by increasing disease burden, environmental persistence, occurrence in multiple animal hosts and complex antimicrobial resistance (AMR) patterns. Unlike classical zoonotic pathogens, most NTM are primarily acquired from shared environmental reservoirs rather than through sustained host-to-host transmission. This review examines NTM from a One Health perspective, focusing on AMR, ecology, animal occurrence, cross-species exposure and public health relevance. METHODS:A narrative review of the current literature was conducted to synthesize evidence on the ecology, environmental reservoirs, occurrence in animals, transmission patterns and AMR mechanisms of NTM. Particular attention was given to studies addressing the human-animal-environment interface and the implications of NTM for One Health surveillance and risk assessment. RESULTS:The reviewed literature shows that NTM are widely distributed in water, soil, sediments and biofilms, creating repeated opportunities for exposure in both animals and humans. They have been reported in livestock, wildlife, companion animals, reptiles and aquatic organisms, where they may act as colonizers, opportunistic pathogens, or sources of diagnostic interference. Evidence for direct animal-to-human transmission remains limited, but animal and environmental findings are important for understanding ecological overlap, host range and circulation of resistant strains. AMR in NTM is shaped by intrinsic resistance, acquired mutations, efflux activity, and biofilm-associated tolerance, which together complicate treatment and resistance prediction. CONCLUSIONS:NTM should be considered environmentally maintained, multi-host organisms of increasing One Health importance rather than conventional zoonotic pathogens. Improved interdisciplinary surveillance, diagnostics and research are needed to clarify exposure pathways, resistance development and public health risk.

Infection with the bacterium C. perfringens in sheep and goat herds leads to considerable losses. The most common diseases in small ruminants caused by this bacterium are pulpy kidney disease, enterotoxaemia, yellow lamb disease, and necrotic enteritis. C. perfringens is widely distributed in the environment and is part of the intestinal microbiota of humans and animals. When physiological conditions in the body change, it begins to produce toxins that lead to various pathological changes. Depending on the toxins it produces, it is classified into seven types (A–G), defined based on the presence of genes encoding the CPA toxin (all types), CPB toxin (type B and type C), ETX toxin (type B and D), ITX toxin (type E), CPE toxin (type F) and NetB toxin (type G). Strains A and D are most commonly associated with enterotoxaemia in small ruminants. According to the available literature, C. perfringens toxinotype A is most frequently isolated in small ruminant herds. In addition to toxin genes, antibiotic resistance genes also play an important role in bacterial survival. Of the genetic determinants of antimicrobial resistance discovered to date, most are associated with the following antimicrobial drugs: bacitracin (bcrR gene), tetracyclines (tet genes), macrolides (erm genes), lincosamides (erm and lnu genes), streptogramins (erm genes) and chloramphenicol (cat genes). Due to sudden death after the onset of symptoms and the economic unprofitability, very few results are available on antibiotic resistance of C. perfringens in small ruminants. Therefore, it has proven to be more economical and effective to work on prevention than on treatment. Since there is no vaccine against enterotoxaemia in Croatia, prevention of the disease is difficult.

Background Human brucellosis remains endemic in Bosnia and Herzegovina (B&H), yet integrative studies explaining transmission patterns, population structure, and susceptibility profiles in an endemic setting are lacking. This study aimed to characterise human Brucella melitensis (B. melitensis) isolates from B&H using a combined epidemiological, phenotypic, and genomic approach. Methods A total of 60 B. melitensis blood isolates obtained from patients with confirmed brucellosis between 2015 and 2021 were selected from a multicentre collection for phenotypic antimicrobial susceptibility testing (AST) and whole-genome sequencing (WGS). Broth microdilution (BMD) in three different broth media was used and interpreted according to the Clinical and Laboratory Standards Institute (CLSI) and European Committee on Antimicrobial Susceptibility Testing (EUCAST) criteria. Genomic analyses included phylogenomic contextualisation using publicly available genomes, and screening for acquired antimicrobial resistance determinants and virulence-associated genes. Results Human brucellosis predominantly affected working-age males and was strongly associated with occupational and household exposure. While phenotypic AST showed that first-line antimicrobials remain effective in vitro, the results were significantly impacted by both the choice of culture media and the interpretive framework, with major discrepancies observed between CLSI and EUCAST classification, particularly for streptomycin and trimethoprim–sulfamethoxazole. WGS revealed a high degree of clustered genomic homogeneity within the East Mediterranean lineage. No acquired antimicrobial resistance (AMR) genes were detected, while a conserved virulence gene repertoire was observed across isolates, including genes associated with membrane adaptation such as mprF. Conclusions Human brucellosis in B&H is characterised by sustained endemic transmission within a genetically conserved B. melitensis population. Integration of epidemiological, phenotypic AST, and genomic data highlights the importance of interpreting susceptibility patterns in the light of Brucella’s slow evolutionary dynamics and local epidemiological context. The genomic baseline established in this study supports future One Health surveillance integrating human and animal reservoirs.

This paper outlines the results of researching the incidence of mastitis in small ruminants in the Republic of Croatia over a six-year period (2017 to 2022). During this period, microbiological testing was performed on 801 samples of udder secretions from small ruminants in 13 counties and the city of Zagreb, with 178 samples (22.2%) testing positive for mastitis pathogens. Of the total 609 udder secretion samples from goats, mastitis agents were isolated from 150 samples (24.6%), while the 192 udder secretion samples from sheep revealed 28 (14.6%) contained mastitis agents. The highest prevalence of mastitis pathogens in goat udder secretions was found in 2018 (31.8%), and in sheep in 2020 (32.9%). Microbiological testing identified 16 species and genera of bacteria. The most common species were Staphylococcus aureus, isolated from 96 (53.9%) samples, Staphylococcusspp. (46 samples; 25.8%), Streptococcus spp. (7; 3.9%), Klebsiella spp. and Corynebacterium spp. (each 5; 2.8%), Escherichia coli (4; 2.2%), Streptococcus uberis and Proteus spp. (each 3; 1.7%), and Pseudomonas spp. (2; 1.1%). Other species and genera, such as Streptococcus agalactiae, Streptococcus dysgalactiae, Pasteurella spp., Mannheimia haemolytica, Enterococcus spp., Enterobacter and Serratia spp. were isolated sporadically, each from one sample. The isolated bacterial cultures were tested for sensitivity to antimicrobials using the disc-diffusion method to amoxicillin with clavulanic acid, ampicillin, cefaperazone, enrofloxacin, kanamycin, cloxacillin, lincomycin, neomycin, novobiocin, penicillin, streptomycin, sulfamethoxazole withtrimethoprim, and tetracycline. Sensitivity of the isolated agents to the antimicrobials was most pronounced towards cefoperazone and enrofloxacin, regardless of the species or genera of the isolated mastitis agent. The odds of isolating a mastitis agent from goat udder secretions was 1.61 times higher than for sheep (P<0.05). This study confirmed that the occurrenceof mastitis in small ruminants in Croatia is comparable to incidences reported in other Mediterranean countries.

Urinary tract infections in dogs are common in veterinary practice and one of the main reasons for the use of antimicrobial drugs. They are mostly caused by bacterial infections, while viral, fungal and parasitic infections account for less than 1% of cases. In practice, treatment usually starts with antimicrobial drugs selected based on existing clinical experience, without knowing the specific pathogen or its sensitivity to a particular drug. The aim of this study was to present the local prevalence andantimicrobial resistance of the most common bacterial pathogens of dog urinary tract infections isolated from samples obtained in the city Split, Croatia and its surrounding areas. From January 2019 to July 2024, 897 urine samples were analysed bacteriologically, of which 307 were positive. Of the total number of bacterial isolates, 194 (62.8%) were Gram-negative bacteria and 115 (37.2%) were Gram-positive. The most frequently isolated bacterial pathogens were E. coli (45%), coagulase-positive Staphylococcus sp. (13.9%), Proteus sp. (10%), beta-haemolytic Streptococcus sp. (9.7%), coagulase-negative Staphylococcus sp. (7.4%), Enterococcus sp. (5.5%), Pseudomonas sp. (4.2%) and Klebsiella sp. (2.6%). Data on local susceptibility and resistance patterns of the most common uropathogens can help clinicians in the selection of antimicrobial drugs and can serve as a basis for antimicrobial resistance monitoring in the coming years.

Rapid and accurate serotyping of Salmonella (S.) enterica subsp. enterica serovars is essential for effective public health surveillance, outbreak control, and food safety management. Traditional serotyping, although considered the gold standard, is time-consuming, technically demanding, and costly. This study aimed to evaluate the applicability of artificial intelligence (AI)-enhanced Fourier-transform infrared (FT-IR) spectroscopy using an IR Biotyper (Bruker Daltonics, Bremen, Germany) for the rapid and accurate serotyping of Salmonella enterica subsp. enterica isolates in Croatia. Materials and Methods: A total of 143 isolates representing different S. enterica serovars of human and food origin were analysed using the IR Biotyper. Each strain was tested in three biological and at least three technical replicates. The obtained results were compared with traditional serotyping according to the Kauffmann–White–Le Minor scheme. Isolate identification at the genus level was further confirmed by MALDI-TOF mass spectrometry. Results: The IR Biotyper demonstrated high reproducibility and complete concordance with standard serotyping methods, enabling accurate differentiation of the most prevalent S. enterica serovars in Croatia. Conclusions: Our findings demonstrate the applicability of FT-IR in routine laboratory work, with the potential to reduce typing time, reduce the number of strains, and lower overall costs required for epidemiological surveillance within the One Health approach.

Objectives: To characterize the genetic basis of azithromycin resistance in Escherichia coli and Salmonella collected within the EU harmonized antimicrobial resistance (AMR) surveillance programme in 2014-18 and the Danish AMR surveillance programme in 2016-19. Methods: WGS data of 1007 E. coli [165 azithromycin resistant (MIC > 16 mg/L)] and 269 Salmonella [29 azithromycin resistant (MIC > 16 mg/L)] were screened for acquired macrolide resistance genes and mutations in rplDV, 23S rRNA and acrB genes using ResFinder v4.0, AMRFinder Plus and custom scripts. Genotype-phenotype concordance was determined for all isolates. Transferability of mef(C)-mph(G)-carrying plasmids was assessed by conjugation experiments. Results: mph(A), mph(B), mef(B), erm(B) and mef(C)-mph(G) were detected in E. coli and Salmonella, whereas erm(C), erm(42), ere(A) and mph(E)-msr(E) were detected in E. coli only. The presence of macrolide resistance genes, alone or in combination, was concordant with the azithromycin-resistant phenotype in 69% of isolates. Distinct mph(A) operon structures were observed in azithromycin-susceptible (n = 50) and -resistant (n = 136) isolates. mef(C)-mph(G) were detected in porcine and bovine E. coli and in porcine Salmonella enterica serovar Derby and Salmonella enterica 1,4, [5],12:i:-, flanked downstream by ISCR2 or TnAs1 and associated with IncI gamma and IncFII plasmids. Conclusions: Diverse azithromycin resistance genes were detected in E. coli and Salmonella from food-producing animals and meat in Europe. Azithromycin resistance genes mef(C)-mph(G) and erm(42) appear to be emerging primarily in porcine E. coli isolates. The identification of distinct mph(A) operon structures in susceptible and resistant isolates increases the predictive power of WGS-based methods for in silico detection of azithromycin resistance in Enterobacterales.

Mycobacterium avium subsp. avium is pathogenic mainly to birds, although cases of mycobacteriosis caused by these bacteria have also been reported in other animals and humans. Not much is known about the effects of this pathogen on otters. The aim of this study was to report for the first time the isolation of M. avium subsp. avium in wild otter and to describe its multidrug resistance profile. A female otter injured in a car accident was found dead and subjected to postmortem examination. Apart from the trauma changes, no other macroscopic pathological changes were detected. Bacteriologic examination revealed the presence of acid-fast bacilli in the lymph nodes, which were confirmed by molecular methods as M. avium subsp. avium. Antimicrobial susceptibility testing revealed susceptibility to clarithromycin and amikacin, but resistance to linezolid, moxifloxacin, streptomycin, isoniazid, trimethoprim/sulfamethoxazole, ciprofloxacin, doxycycline, and ethionamide. This is unusual for wild species, which generally should not come into contact with antimicrobials, and may suggest that multidrug-resistant MAC strains are circulating between wild and domestic animals. These results emphasise the need for additional epidemiological studies on non-tuberculous mycobacteria in wildlife and their implications for one health.

Bacillus anthracis, the causative agent of anthrax disease, is a worldwide threat to livestock, wildlife and public health. It is also considered one of the most important pathogens of bioterrorism. Rapid and reliable diagnosis and administration of antimicrobials are essential for effective anthrax treatment. In this study, we determined the in vitro susceptibilities of 40 isolates of B. anthracis isolated in Croatia over the recent two decades to 18 antimicrobials. Whole-genome sequencing was performed, and bioinformatics tools were used to determine virulence factors and antimicrobial resistance genes. Core genome-based multilocus sequence typing was used for isolate comparison and phylogenetic analysis. All isolates were susceptible to all antimicrobials recommended for post-exposure prophylaxis or anthrax therapy. Susceptibility was found to all other tested antimicrobials that are an alternative for primary therapy. We found two beta-lactamase genes, but their expression is not sufficient to confer resistance. In all isolates used in this study, we found 21 virulence genes, 8 of which are responsible for toxin and capsule production. As far as phylogenetic analysis is concerned, the B. anthracis isolates from Croatia are categorised into two clades. The first is clade A, subclade Trans Eurasia, and the other is clade B, subclade B2.

Bakterijske su infekcije urinarnog trakta (IUT) u pasa učestale. Porast antimikrobne rezistencije i uporaba kritično-važnih antimikrobnih lijekova, osobito u liječenju IUT pasa, zabrinjavajuća je zbog pojave multiplo rezistentnih bakterijskih sojeva. Cilj je ovog rada bio prikazati prevalenciju i antimikrobnu resistenciju najčešćih bakterijskih uzročnika IUT pasa i trendove antimikrobne rezistencije izdvojenih bakterijskih sojeva u Republici Hrvatskoj tijekom 11 godina. Od ukupno 2721 pretraženih uzoraka urina, potitivno je bilo 1363 (50,1 %). Bakterijska vrsta Escherichia coli bila je najčešće izdvojeni mikroorganizam (47,3 %), nakon čega slijede: koagulaza pozitivni Staphylococcus sp. (20,7 %), Proteus sp. (14,7 %), Enterococcus sp. (13,6 %), beta hemolitični Streptococcus sp. (11,7 %), Pseudomonas aeruginosa (4,5 %) i meticilin rezistentni koagulaza pozitivni Staphylococcus sp. (3,4 %). Kod Gram-negativnih bakterija uočen je visok stupanj osjetljivosti na: gentamicin, amikacin (77,9 %-97,3 %), marbofloksacin i ciprofloksacin (69,7 %-98,4 %). Kod bakterijskog roda Proteus utvrđen je i visok stupanj osjetljivosti na beta-laktame (70,5 %-86,7 %), a kod Escherichia coli i na kloramfenikol (73,3 %) i trimetoprim/sulfametoksazol (72,7 %). Neznatan postotak koagulaza pozitivnih Staphylococcus sp. bila je osjetljiva na penicilin (10,6 %) i ampicilin (16,7 %), dok je mala osjetljivost zamijećena na streptomicin, neomicin i tetracikline (56,0 %-66,0 %). Najmanji postotak beta hemolitičnih Streptococcus sp. bio je osjetljiv na aminoglikozide, tetracikline (8,2 %-31,9 %) i fluorokinolone (31,5 %-61,6 %). Kod bakterijskih izolata Enterococcus sp. najveća osjetljivost prisutna je na amoksicilin/klavulansku kiselinu (78,0 %) i ampicilin (70,4 %). Amikacin i kloramfenikol, s postotkom osjetljivosti od 89,3 %, odnosno 80,9 %, bili su jedini antimikrobni lijekovi učinkoviti na meticilin rezistentne koagulaza pozitivne Staphylococcus sp. Tijekom 11 godina istraživanja zamijećen je trend porasta antimikrobne rezistencije bakterija Escherichia coli i Proteus sp., izdvojenih iz IUT pasa, na fluorokinolone, ampicilin i amoksicilin/klavulansku kiselinu, dok je kod bakterijske vrste Escherichia coli uočen porast antimikrobne rezistencije i na cefalosporine. Ovi rezultati će pomoći pri empirijskom odabiru antimikrobnih lijekova za terapiju IUT pasa te podizanju svijesti o razumnoj uporabi antimikrobnih lijekova.

The emergence and rapid spread of the plasmid-mediated colistin-resistant mcr-1 gene introduced a serious threat to public health. In 2021, a multi-drug resistant, mcr-1 positive Escherichia coli EC1945 strain, was isolated from pig caecal content in Croatia. Antimicrobial susceptibility testing and whole genome sequencing were performed. Bioinformatics tools were used to determine the presence of resistance genes, plasmid Inc groups, serotype, sequence type, virulence factors, and plasmid reconstruction. The isolated strain showed phenotypic and genotypic resistance to nine antimicrobial classes. It was resistant to colistin, gentamicin, ampicillin, cefepime, cefotaxime, ceftazidime, sulfamethoxazole, chloramphenicol, nalidixic acid, and ciprofloxacin. Antimicrobial resistance genes included mcr-1, blaTEM-1B, blaCTX-M-1, aac(3)-IId, aph(3’)-Ia, aadA5, sul2, catA1, gyrA (S83L, D87N), and parC (A56T, S80I). The mcr-1 gene was located within the conjugative IncX4 plasmid. IncI1, IncFIB, and IncFII plasmids were also detected. The isolate also harbored 14 virulence genes and was classified as ST744 and O101:H10. ST744 is a member of the ST10 group which includes commensal, extraintestinal pathogenic E. coli isolates that play a crucial role as a reservoir of genes. Further efforts are needed to identify mcr-1-carrying E. coli isolates in Croatia, especially in food-producing animals to identify such gene reservoirs.

Objectives: Non-tuberculous mycobacteria are opportunistic pathogens that cause disease mainly in im-munocompromised hosts. The present study assessed the prevalence of antibiotic resistance among such mycobacteria from domestic and wild animals in Croatia sampled during several years within a national surveillance program.Methods: A total of 44 isolates belonging to nine slow-growing species were genotyped and analyzed for susceptibility to 13 antimicrobials often used to treat non-tuberculous mycobacterial infections in humans.Results: Most prevalent resistance was to moxifloxacin (77.3%), doxycycline (76.9%), and rifampicin (76.9%), followed by ciprofloxacin (65.4%), trimethoprim-sulfamethoxazole (65.4%), and linezolid (61.4%). Few isolates were resistant to rifabutin (7.7%) or amikacin (6.8%). None of the isolates was resistant to clarithromycin. Nearly all isolates (86.4%) were resistant to multiple antibiotics.Conclusion: Our findings suggest substantial risk that human populations may experience zoonotic in-fections with non-tuberculous mycobacteria that will be difficult to treat using the current generation of antibiotics. Future work should clarify how resistance emerges in wild populations of non-tuberculous mycobacteria.& COPY; 2023 The Author(s). Published by Elsevier Ltd on behalf of International Society for Antimicrobial Chemotherapy.This is an open access article under the CC BY-NC-ND license ( http://creativecommons.org/licenses/by-nc-nd/4.0/ )

In the era of growing antimicrobial resistance, a threat affecting humans, endangering animals, as well as livelihoods and food security worldwide, we wanted to find possible explanations for its continuous spread from a new perspective. The ubiquity of resistance genes requires a One Health approach to finding the explanations for continuous AMR spread. The natural transformability of Campylobacter jejuni, its high incidence of infections, and emerging resistance worldwide inspired us to choose C. jejuni ST-21CC to be our pathogen for analyzing its contribution and connection to the cycle of AMR dissemination. ST-21CC is known as a generalist among humans and broilers, the most prevalent lineage worldwide, but it is rarely found in wild birds. Emerging in wild birds, genetic relatedness and similar resistance profiles were expected. We analyzed 23 Croatian C. jejuni strains belonging specifically to ST-21CC from humans, broilers, and wild birds. The genomic data obtained through whole genome sequencing and phenotypic susceptibility data of strains were compared. Our findings suggest high fluoroquinolone resistance in ST-21CC strains, with more diverse genetic backgrounds in wild birds. Intriguing were three isolates of ST-822 (from human and storks), sharing a similar genetic fingerprint.

Non-tuberculous mycobacteria (NTM) are opportunistic pathogens capable of causing infections in humans and animals. The aim of this study was to demonstrate the potential role of domestic and wild animals as a reservoir of multiple resistant, rapidly growing NTM strains representing a potential zoonotic threat to humans. A total of 87 animal isolates belonging to 11 rapidly growing species (visible colonies appear within three to seven days) were genotyped and tested for susceptibility to the 15 most commonly used antibiotics in the treatment of such infections in a human clinic. By determining the antimicrobial susceptibility, the most prevalent resistance was found to cephalosporins (>50%), followed by amoxicillin–clavulanate (31.0%), clarithromycin (23.0%), tobramycin (14.9%) and doxycycline (10.3%). Resistance to imipenem, ciprofloxacin, minocycline and linezolid was notably lower (<7.0%). All tested isolates were susceptible to amikacin and moxifloxacin. The most frequent resistance was proved in the most pathogenic species: M. fortuitum, M. neoaurum, M. vaccae and M. porcinum. Meanwhile, other species displayed a higher sensitivity rate. No significant resistance differences between domestic and wild animals were found. The established significant frequency of resistance highlights the significant zoonotic potential posed by circulating rapidly growing NTM strains, which could lead to challenges in the treatment of these infections.

Campylobacter lari is a thermotolerant bacterium that sporadically causes gastrointestinal diseases in humans and can be found in wildlife and the environment. C. lari is an understudied species, especially in wild birds such as gulls. Gulls are potentially good carriers of pathogens due to their opportunistic behavior and tendency to gather in large flocks. During winter and their breeding period, 1753 gulls were captured, and cloacal swabs were taken to be tested for the presence of C. lari. From isolated bacteria, the DNA was sequenced, and sequence types (ST) were determined. Sixty-four swabs were positive for C. lari, and from those, forty-three different STs were determined, of which thirty-one were newly described. The whole genome was sequenced for 43 random isolates, and the same isolates were tested for antimicrobial susceptibility using the broth microdilution method to compare them to WGS-derived antimicrobial-resistant isolates. All the tested strains were susceptible to erythromycin, gentamicin, and chloramphenicol, and all were resistant to ciprofloxacin. Resistance to ciprofloxacin was attributed to a gyrA_2 T86V mutation. Genes connected to possible beta-lactam resistance (blaOXA genes) were also detected.

IntroductionShortly before the mass mortality event of the noble pen shell (Pinna nobilis) population in the south-eastern Adriatic coast, two rapidly growing Mycobacterium strains CVI_P3T (DSM 114013 T, ATCC TSD-295 T) and CVI_P4 were obtained from the organs of individual mollusks during the regular health status monitoring.MethodsThe strains were identified as members of the genus Mycobacterium using basic phenotypic characteristics, genus-specific PCR assays targeting the hsp65 and 16S rRNA genes and the commercial hybridization kit GenoType Mycobacterium CM (Hain Lifescience, Germany). MALDI-TOF mass spectrometry did not provide reliable identification using the Bruker Biotyper Database.Results and discussionGenome-wide phylogeny and average nucleotide identity (ANI) values confirmed that the studied strains are clearly differentiated from their closest phylogenetic relative Mycobacterium aromaticivorans and other validly published Mycobacterium species (ANI ≤ 85.0%). The type strain CVI_P3T was further characterized by a polyphasic approach using both phenotypic and genotypic methods. Based on the phenotypic, chemotaxonomic and phylogenetic results, we conclude that strains CVI_P3T and CVI_P4 represent a novel species, for which the name Mycobacterium pinniadriaticum sp. nov. is proposed.

Viral enteric pathogens continuously burden intensive pig farming, causing gastrointestinal diseases of epidemic and endemic nature. The present study investigated two diarrhoea outbreaks on a large farrow-to-finish holding and subsequent circulation of outbreak-related enteric viruses. These viruses were characterised by whole genome sequencing, and statistical evaluation of the impact on specific production metrics was performed. The results provided evidence that the Porcine epidemic diarrhoea virus-swine enteric coronavirus (PEDV-SeCoV) S gene recombinant strain was responsible for the first outbreak, whilst Rotavirus A (RVA) in a mixed infection with Rotavirus B (RVB) and porcine kobuvirus (PKV) probably caused the second diarrhoea outbreak. Whole genome characterisation revealed a porcine origin of all viruses involved and significant heterogeneity of RVB strain, proposing four novel genotypes and changes in RVB VP1 genotype classification. The statistical evaluation confirmed only a minor disturbance in the number of weaned pigs per sow, with statistical forecasting showing positive trends. A follow-up study corroborated the endemicity of RVA and PKV, in contrast to PEDV-SeCoV. Punctual, comprehensive and timely investigation of diarrhoea outbreaks is a prerequisite for applying adequate pig health and biosecurity management. Calculating such outbreaks' impact on production metrics can potentially shape future decisions on management improvements.