Search Results (1,884)

Background/Objectives: In Europe, Pseudomonas aeruginosa is the second most common cause of ventilator-associated pneumonia in intensive care units. Intrinsic antibiotic resistance and acquired carbapenemases can lead to high mortality. To guide more targeted antimicrobial therapy and adequate infection control measures, we performed a multicenter study on the prevalence and genetic basis of carbapenem resistance among P. aeruginosa (CR-PA) across 17 community hospitals in Austria. Methods: During a 3-month period, we collected 621 P. aeruginosa isolates from 560 patients. Antibiotic susceptibility testing was performed according to EUCAST guidelines, and all CR-PA isolates were subjected to whole genome sequencing. Results: Antibiotic susceptibility testing revealed carbapenem resistance in 5.41% (36/621) of the investigated P. aeruginosa isolates. Only 3 produced a carbapenemase (2 Verona Integron-encoded Metallo- ß-lactamases and 1 Imipenemase Metallo-ß-lactamase) and carried a carbapenemase-encoding gene. Among the studied P. aeruginosa isolates there was a high genetic diversity, excluding a single driving epidemic lineage in the included Austrian hospitals. Conclusions: The absence of interhospital clonal dominance suggests that carbapenem resistance emerged independently in different centers, likely driven by local antibiotic selection pressures rather than regional clonal spread. Full article

Antimicrobial resistance (AMR) in companion animals is an escalating concern at the interface of veterinary medicine and public health. Dogs and cats, the most commonly treated companion species, are frequently prescribed antimicrobials for dermatological, otic, urinary, and respiratory infections—often involving drug classes that are critically important in human medicine. This overlap underscores the need for judicious use and integrated stewardship within a One Health framework. This narrative review synthesizes current evidence on AMR in companion animals and its implications for One Health. Studies were included if they reported AMR in dogs and cats and addressed zoonotic aspects. Staphylococcus pseudintermedius, S. aureus, Escherichia coli, Pseudomonas aeruginosa, and Enterococcus sp. are examples of clinically significant organisms that are becoming more resistant to several antibiotic classes, which can result in treatment failures and extended illness. Horizontal gene transfer facilitates the spread of resistance determinants across bacterial populations. Improved surveillance systems, prudent antibiotic use, regular culture and susceptibility testing, and enhanced antimicrobial stewardship in veterinary practice are just a few of the many strategies needed to address AMR in companion animals. The integration of companion animals into AMR surveillance, stewardship programs, and infection control strategies is essential. Coordinated One Health interventions are urgently required to mitigate the spread of AMR. Full article

Klebsiella pneumoniae is an opportunistic pathogen associated with both community-acquired and nosocomial infections. Multidrug-resistant (MDR) strains are increasingly implicated in urinary tract infections (UTIs), traveller’s diarrhoea, bacteraemia, and sepsis. β-lactam antibiotics are commonly used for treatment; however, antimicrobial resistance has emerged largely due to the production of extended-spectrum β-lactamases (ESBLs), which confer resistance mainly to penicillins, oxyimino-cephalosporins, and monobactams, while cephamycins and carbapenems usually remain stable to ESBL-mediated hydrolysis and compromise therapeutic efficacy. ESBL-producing strains represent a major cause of severe Gram-negative infections. This study aimed to determine the prevalence of ESBL-producing K. pneumoniae among UTI patients in Jordanian hospitals (Al Mafraq, Ma’an, and Islamic Hospitals), evaluate their antimicrobial susceptibility patterns, and detect antimicrobial resistance genes at the molecular level. A total of 450 urine isolates of K. pneumoniae were collected from UTI patients between November 2023 and May 2024. Isolates were identified in hospital laboratories using standard microbiological methods. Antimicrobial susceptibility testing was performed, and molecular characterisation of ESBL-associated genes was conducted using polymerase chain reaction (PCR). Out of 450 K. pneumoniae isolates collected from UTI patients across three Jordanian regions, 72 (16%) were confirmed as ESBL producers. Among the 72 ESBL-positive K. pneumoniae isolates, 34 (47.2%) were recovered from the Central region, 20 (27.8%) from the North, and 18 (25.0%) from the South. Molecular analysis revealed that 41.7% of ESBL-producing isolates carried the blaCTX-M gene, while 33.3% harboured the blaOXA gene. All ESBL-producing isolates demonstrated antimicrobial resistance to third-generation cephalosporins. A significantly higher proportion of ESBL-producing isolates was identified in female patients (84.7%) compared with males (15.3%). A significant association was observed between blaOXA gene distribution and geographic region (p = 0.016), whereas blaCTX-M gene distribution showed no significant regional association. ESBL-producing K. pneumoniae accounted for a substantial proportion of UTI isolates in Jordan, with blaCTX-M identified as the predominant resistance gene. The higher burden observed in the Central region and among female patients highlights notable distribution patterns in this cohort. These findings emphasise the necessity for sustained molecular surveillance and strengthened antimicrobial stewardship strategies to limit the dissemination of ESBL-producing strains in Jordanian healthcare settings. Full article

Rising antimicrobial resistance has reduced the effectiveness of empirical eradication regimens for Helicobacter pylori (H. pylori) infection, particularly those containing clarithromycin. Local resistance surveillance and identification of clinical predictors of resistance are essential to guide treatment strategies. This study evaluated antimicrobial resistance patterns and clinical determinants of resistance in a real-world tertiary-care cohort. A retrospective observational study was performed, which included 352 adult patients with confirmed H. pylori infection managed between November 2022 and November 2025. Of these, 168 patients underwent culture and antibiotic susceptibility testing, while 184 received empirical therapy. Resistance rates were calculated according to the number of isolates tested for each antimicrobial agent (available-case analysis). Multivariable logistic regression analysis was used to identify independent predictors of resistance. Among susceptibility-tested patients, resistance to at least one antimicrobial agent was detected in 44.6%. Clarithromycin resistance was most frequent (42.5%), followed by metronidazole (36.4%) and levofloxacin (14.0%), whereas amoxicillin resistance remained low (2.4%). Multidrug resistance (MDR) based on available susceptibility data was observed in 12.5% of cases, most commonly involving dual clarithromycin–metronidazole resistance. Prior eradication therapy was independently associated with resistance (adjusted Odds Ratio aOR 2.41; 95% Confidence Interval CI 1.29–4.51; p = 0.006), while demographic factors were not. Clarithromycin resistance substantially exceeds recommended thresholds for empirical triple therapy in this setting. Prior eradication therapy is the principal predictor of resistance, supporting resistance-informed and stewardship-oriented management strategies. Full article

During the COVID-19 pandemic carbapenem-resistant Acinetobacter baumannii (CRAB) were found to be the major pathogen associated with ventilator-associated pneumonia in mechanically ventilated patients. This prompted us to analyze the post-pandemic mechanisms of carbapenem resistance, antibiotic resistance trends, and molecular epidemiology of CRAB in Croatia. In total, 94 CRAB isolates from two hospital centers, including outpatient settings, were investigated. Antimicrobial susceptibility testing was performed by broth microdilution. PCR was used to detect genes encoding carbapenemases of group A, B and D and extended-spectrum β-lactamases (ESBL). Randomly selected isolates were subjected to whole resistome analysis by Inter-array CarbaResist Kit and whole-genome sequencing (WGS). Phylogenetic tree and sequence types (STs) were retrieved from WGS. Plasmid incompatibility groups were determined by PCR-based replicon typing (PBRT). All isolates were extensively drug resistant (XDR), showing resistance to ceftazidime, cefepime, piperacillin–tazobactam, imipenem, meropenem, gentamicin, amikacin and ciprofloxacin, and 13% (n = 12) were also resistant to colistin. The Hodge and CIM test exhibited poor sensitivity with only 32 and 30% of isolates being identified as carbapenemase producers, respectively. PCR identified bla_OXA-23 as the dominant carbapenemase gene in both hospitals, found in 71% of the isolates (67/94). In an outpatient setting, bla_OXA-24/40 was dominant. bla_OXA-23 and bla_OXA-72 were the only allelic variants. The Inter-array CarbaResist Kit and whole-genome sequencing (WGS) identified a variety of aminoglycoside (armA, ant(3″)-IIa, aph(3″)-Ib, aph(6)-Id) and sulphonamide resistance (sul1 and sul2) genes. The representative bla_OXA-23-positive isolates belonged to ST2, while bla_OXA-72-positive isolates were allocated to ST492. These data show that there are different populations of XDR A. baumannii between hospital and outpatients. Full article

Antimicrobial resistance in bovine mastitis pathogens poses interconnected threats to dairy productivity and public health; however, longitudinal evidence on the association between veterinary oversight and lower resistance to critically important antimicrobials in tropical smallholder systems remains limited. This study analyzed 1347 quarter milk samples from 47 dairy farms in Saraburi Province, Thailand, submitted consecutively over five years (2020–2025), to evaluate whether participation in a veterinary-led herd health (HH) program was independently associated with reduced vancomycin resistance and multidrug resistance (MDR). Bacterial identification was conducted using standard methods, and susceptibility was determined using the Kirby–Bauer disk diffusion method. Among 1069 culture-positive samples, Streptococcus spp. (25.3%) and coagulase-negative staphylococci (16.8%) predominated. Vancomycin resistance declined from 15.9% to 5.4% between early (2020–2022) and recent (2023–2025) periods. Of the 686 isolates tested against ≥3 antibiotic classes, 61 (8.9%) were MDR; vancomycin resistance co-occurred in 34.4% of these samples. Repeated logistic regression identified non-HH farm status (OR = 4.035; p = 0.027) and early-year groups (OR = 4.611; p = 0.002) as independent risk factors for vancomycin resistance. As HH participation and year group showed a significant interaction, their joint effect for MDR was modeled: compared with non-HH farms in the early period (reference), all other combinations—including HH farms in 2023, HH farms in 2020, and non-HH farms in 2023—were associated with significantly lower odds of MDR. These findings provide the first evidence from Thailand that structured veterinary herd health programs are independently associated with lower critically important antimicrobial resistance, supporting their integration into a One-Health stewardship policy. Full article

The occurrence of the European brown hare (Lepus europaeus Pallas 1778) has declined throughout Europe in recent years. However, it remains economically valuable as an important game species. To date, information on the individual microbiota of the European hare has been limited. The phylum Firmicutes (Bacillota) was dominant, and enterococci belong to this phylum. However, they can carry virulence factor genes. Therefore, this study aimed to address two aspects: the health of hares due to their recent decline, and, as a game animal, the protection of consumers’ health. Based on MALDI-TOF mass spectrometry, five strains were identified as Enterococcus faecium and two as E. faecalis; these findings were confirmed by genotyping using PCR and phenotypic analysis. The average value of lactic acid production was 0.680 ± 0.005 mmol/L. The strains lacked the virulence factor genes esp, agg, and gelE. However, they showed susceptibility to antibiotics and to postbiotic substances, even to 13 of 14 tested. PS/Ent M appears to be the most active PS against tested strains, with inhibitory activity of 25,600 AU/mL. Postbiotic substances represent a new tool for preventing unwanted microbiota in game animals. Full article

Chronic wounds represent a major complication of underlying conditions such as diabetes mellitus, arterial ischemia, surgical wound and burns. This study aimed at the phenotypic and molecular characterization of antimicrobial resistance for a selection of bacterial isolates, originating from wounds harvested from patients hospitalized in the Vascular Surgery and Plastic Surgery wards. The microbiological diagnosis of wound infections was established according to the laboratory’s working protocol. PCR screening of antibiotic resistance genes was performed using a real-time PCR, while the microtiter plate assay was used to determine the biofilm-forming capacity. Testing of biofilm susceptibility to meropenem and amikacin was performed on Calgary biofilm device. Of the 88 bacterial isolates studied, 78.40% were Gram-negative bacilli (GNB)—Klebsiella pneumoniae (K.P), Pseudomonas aeruginosa (P.A), Proteus mirabilis (P.M), Acinetobacter baumannii (A.B), while the remaining 21.60% were Gram-positive cocci (GPC)—Staphylococcus aureus (S.A). All A.B isolates and 92.59% of K.P were carriers of β-lactamase- and carbapenemase-encoding genes, while 57.89% of S. aureus isolates were carriers of mecA (methicillin-resistant). Strong biofilm-forming isolates (B+++) were more frequent in P.A than in K.P (p = 0.002) and P.M (p = 0.02), with a frequency comparable to that of A.B strains (p = 0.212). When analyzing the biofilm reaction to meropenem, a significantly lower susceptibility was detected in the biofilm for K.P isolates, compared to the planktonic ones. Most GNB have been extensively multidrug-resistant, particularly K.P and A.B. Isolates from chronic wounds are major biofilm-formers. A strong and statistically significant association has been identified in the case of K.P and P.M between the presence of resistance genes and the biofilm-forming capacity. These findings highlight the need for a customized therapeutic approach for each chronic wound, considering the mechanisms underlying treatment resistance. These include bacterial virulence factors and the wound microenvironment colonized by the biofilm and the relative contribution of each to the overall resistance profile. Full article

Spinal infections in general, and infectious spondylodiscitis in particular, are increasingly diagnosed in the Western world, in recent decades. This rise in incidence is associated with an ageing population and with an increased availability of accurate diagnostic modalities. Even so, due to the non-specific nature of clinical manifestations, and of the implicated blood and serum markers, there is a risk of underdiagnosis or misdiagnosis of the disease in its initial stages. Ionizing radiation methods, such as plain radiography (X-ray) and computed tomography (CT), are also not reliable in the early stages of the diseases, and the golden standard of imagistic diagnosis, magnetic resonance imaging (MRI), is not always available or requested. Still, MRI remains the most reliable method in most cases where there is a need for differential diagnosis with other pathologies, namely Andersson lesions, destructive spondyloarthropathy, erosive osteochondritis, micro-crystalline spondylitis, Modic 1 lesion, Charcot spinal arthropathy, osteoporotic fractures, SAPHO syndrome with spinal involvement, and Schmorl’s nodes. Infectious spondylodiscitis is caused by bacteria, and, less frequently, by fungi. Rare cases of parasitic causes have also been reported in the literature. Infectious spondylodiscitis of bacterial causes may be pyogenic, more frequently caused by Staphylococcus spp. or Streptococcus spp., or granulomatous, usually caused by Mycobacterium tuberculosis complex (MTBC) or from classical brucellosis. In all these cases, therapy may be conservative, with antibiotics, or surgical, when the former fails or in patients with significant spinal instability or other neurological manifestations. There are various surgical approaches, each with its own drawbacks, and usually used according to the preference of the attending physician. Even in cases of surgical treatment, antibiotic administration is prolonged, and it is important for a proper scheme to be selected based on antimicrobial susceptibility testing. However, given that in many cases, the causative agent cannot be identified, empirical treatment must be initiated. Finally, newer approaches, including the incorporation of antimicrobial substances, may offer better solutions for improving treatment and rehabilitation outcomes. Full article

Antimicrobial resistance is a growing threat to human and animal health and is recognized as a global One Health issue. Strategies to reduce its impact include judicious usage of antibiotics guided by accurate bacterial identification and antimicrobial susceptibility. Next-generation sequencing (NGS) offers a DNA-based diagnostic approach that profiles the bacteria microbiota and can help support more informed antibiotic selection. We utilized NGS to identify Fusobacterium gonidiaformans in the neck abscess of a wild California sea lion (Zalophus californianus) undergoing rehabilitation. Initially, NGS revealed that the microbial population was dominated by F. gonidiaformans. Following treatment, the microbial profile shifted over the following eight weeks, during which 13 other bacterial species were detected, demonstrating the need for repeated testing to monitor changes in persistent lesions. Despite effective treatment to eliminate F. gonidiaformans from the abscess, the patient died during treatment due to suspected unrelated causes. Necropsy and histopathology identified bacterial pneumonia and sepsis associated with a large squamous cell carcinoma of the oropharynx and neck, all contributing to a deadly outcome. To our knowledge, this is the first case report of the use of longitudinal NGS sampling with the identification of Fusobacterium gonidiaformans associated with an abscess in the neck in a California sea lion. These findings support the utility of NGS in monitoring microbial dynamics to allow informed decision-making in antimicrobial selection in complex infections. Full article

Antibiotic resistance (ABR) is a significant threat to human and animal health, as well as to the environment. Antibiotic residues, antibiotic-resistant bacteria and antibiotic resistance genes are emerging contaminants of water resources. The present study aimed to assess the prevalence of ABR among waterborne enterococci in an anthropogenic-affected section of the Yantra River (Bulgaria). The susceptibility of 426 strains to 13 antibiotics (ABs) was tested by the disk diffusion method, and the genes encoding resistance by PCR analyses. A total of 39% of isolates were found to be antibiotic-resistant, with 9% mainly being multidrug-resistant to three AB classes. The most common resistance was to erythromycin (19%), tetracycline (18%) and ampicillin (14%), encoded by the ermB, tetM and blaTEM genes. A total of 3% of isolates were ciprofloxacin-resistant and only 1% was resistant to vancomycin or high-level gentamicin. All isolates were susceptible to teicoplanin and linezolid. Spatial variations in ABR levels were found, with the lowest abundance of antibiotic-resistant enterococci occurring in upstream river waters, away from urban areas, and the highest in urban areas. The spread of waterborne antibiotic-resistant enterococci highlights the need for water pollution management, monitoring and control to limit anthropogenic pressures through wastewater discharges and diffuse fecal pollution, and to ensure the ecological well-being of receiving waters. Full article

Background/Objectives: Antimicrobial resistance is a major public health concern, particularly among multidrug-resistant (MDR) Enterobacterales. Nitroxoline is an older antibiotic with a unique mechanism of action that has not been widely used in recent decades. This study aimed to evaluate the in vitro activity of nitroxoline against Extended-Spectrum Beta-Lactamase (ESBL)-producing Escherichia coli (E. coli) and MDR Klebsiella pneumoniae (K. pneumoniae) isolated from urine samples of outpatients in Split-Dalmatia County, Croatia. Methods: Nitroxoline susceptibility was assessed using disk diffusion for E. coli (n = 26) and broth microdilution for K. pneumoniae (n = 33). Results: ESBL-producing E. coli isolates showed high susceptibility to nitroxoline, with 25 (96.2%) classified as susceptible. In contrast, K. pneumoniae isolates exhibited high minimum inhibitory concentration (MIC) values (range 16–128 mg/L; median 32 mg/L), indicating limited activity. Conclusions: Nitroxoline demonstrated strong in vitro activity against ESBL-producing E. coli but limited activity against MDR K. pneumoniae. Interpretation of the findings for K. pneumoniae is constrained by the lack of established clinical breakpoints. Full article

Background/Objectives: The emergence of antimicrobial resistance (AMR) within a One Health framework highlights the role of wildlife as environmental reservoirs. Because wild game is an increasingly important meat source, hygienic handling during evisceration is critical to prevent carcass contamination from internal tissues such as mesenteric lymph nodes (MLNs). This study aimed to investigate the occurrence and antibiotic resistance (AR) profiles of Escherichia coli isolated from the MLNs of hunted wild ungulates in western Romania to better understand microbiological hazards along the game meat supply chain. Methods: MLN samples were aseptically collected from 103 legally hunted wild boars (Sus scrofa, n = 78) and cervids (Capreolus capreolus and Cervus elaphus, n = 25) across two hunting grounds. E. coli isolation was performed utilizing selective Tryptone Bile X-Glucuronide agar. Subsequent biochemical identification and phenotypic antimicrobial susceptibility testing were conducted using the automated VITEK^® 2 system. Results: The overall E. coli isolation rate was 72.8% (75/103). Analyzed by host species, the bacterium was recovered from 79.4% of the sampled wild boars (62/78) and 52.0% of the cervids (13/25). Phenotypic resistance to at least one antibiotic agent was observed in 25.3% (19/75) of the isolates, most frequently against cephalosporins (cefalexin, 21.3%) and penicillins (ampicillin, 24.0%). Multidrug resistance (MDR) was identified in 20.0% (15/75) of the isolates. Conclusions: The detection of MDR E. coli phenotypes within the MLNs of free-ranging game indicates the penetration of clinically relevant resistance mechanisms into sylvatic environments. These findings underscore the potential risk of internal carcass contamination during field evisceration, highlighting the critical need for strict hygiene practices to ensure game meat safety. Full article

Background: Streptococcus pneumoniae, also referred to as pneumococcus, is of immense public health significance. In particular, it causes severe invasive diseases among children. This has led to the recommendation of anti-pneumococcal prophylaxis, including the administration of penicillin and pneumococcal conjugate vaccines (PCVs), which have become available in about 90% of the countries in sub-Saharan Africa. Nonetheless, breakthrough disease still occurs. Also, PCVs can cause a shift in the distribution of pneumococcal serotypes, usually towards non-vaccine types. However, in many sub-Saharan African countries where PCVs have been introduced, there are hardly any comprehensive post-vaccination surveillance data on pneumococcus. Aim: To describe the post-vaccination epidemiology of invasive pneumococcal disease (IPD) in Ghana, including the prevalence, serotype distribution and antibiotic resistance. Methods: The study was cross-sectional and involved 14,597 patients recruited at the Korle Bu Teaching Hospital, Greater Accra Regional Hospital, Princess Marie Louise Children’s Hospital, Ho Regional Hospital, Eastern Regional Hospital, and Zonal Public Health and Reference Laboratory, Tamale. Specimens of cerebrospinal fluid (obtained by lumbar puncture) and blood were collected routinely from meningitis patients, while blood specimens were taken from pneumonia patients. These were cultured for S. pneumoniae following standard microbiological methods and subjected to antimicrobial susceptibility testing. The isolates were serotyped by the pneumotest latex agglutination kit, and the results confirmed by Quellung reaction, using serotype-specific antisera. Results: The overall prevalence of IPD was 0.66% (n = 97), varying across syndromes: bloodstream infections (0.53%, n = 38), meningitis (2.45%, n = 43), and pneumonia (0.28%, n = 16). The majority of the cases (56.70%, n = 55) occurred in the 11–20-year-old group. Ten pneumococcal serotypes were identified, with Serotype 1 being predominant (58.76%), followed by Serotypes 23B (11.34%), 33F (9.28%), and 12F (8.24%). Vaccine serotypes accounted for 81.44% of the isolates, while 18.56% were non-vaccine serotypes (23A, 23B, and 38). Antimicrobial resistance was highest against sulphamethoxazole-trimethoprim (52%), ampicillin (51%), and penicillin (46%). No resistance was observed against ciprofloxacin, levofloxacin, and vancomycin. The multidrug resistance proportion was 42.3% (n = 41). Conclusions: Even in the post-vaccination era, vaccine-type IPD remains a significant public health issue in Ghana. The observed serotype distribution and antimicrobial resistance patterns warrant sustained surveillance, more adaptive vaccination policies, and rigorous antibiotic stewardship to effectively mitigate IPD burden. Full article

The growing problem of antibiotic resistance poses one of the greatest threats to modern medicine, making the search for new, alternative strategies to treat bacterial infections a matter of priority. The aim of the study was to evaluate the antimicrobial activity of selected postbiotic substances (PS) and nisin against methicillin-susceptible (MS) and methicillin-resistant (MR) strains of coagulase-negative staphylococci (NAS) and mammaliicocci. The study was conducted on 24 strains of coagulase-negative staphylococci and mammaliicocci isolated from milk collected from Holstein-Friesian (HF) cows with subclinical mastitis. In vitro, PS/EMo (100–400 AU/mL) and PS/Eas (100–200 AU/mL) were the most effective, inhibiting the growth of all MS and MR strains of NAS and Mammaliicoccus spp. (100.0%). A high percentage of strains were also sensitive to postbiotic substances produced by Lactococcus lactis subsp. lactis PS/MK2/8 (400–1600 AU/mL), PS/MK1/3 (100–400 AU/mL), and nisin (100–25,600 AU/mL), both in MR strains (94.1%, 82.4%, 88.2%, respectively) and in MS strains (100.0%, 85.7% and 100%, respectively). PS/Esach (100–25,600 AU/mL) inhibited the growth of all strains, including the mecA gene-positive mammaliicocci strains (100.0%), but was slightly less effective against the MS strains (64.7%). The lowest activity was observed with postbiotic substances produced by Enterococcus faecium, PS/4231 (100–1600 AU/mL) and PS/9296 (100–6400 AU/mL), which inhibited the growth of 3 out of 17 MR strains (17.65%). Among the Mammaliicoccus strains with the mecA gene, postbiotic substances derived from strains PS/4231 and PS/9296 inhibited the growth of 42.9% and 28.6% of the strains, respectively. Four tested strains were sensitive to all postbiotic substances (MSC9, MSC11, MSC12 and SCH3). This study confirms that postbiotic substances and nisin inhibit the growth of staphylococci isolated from the milk of cows with subclinical mastitis, including methicillin-resistant strains. Full article