A 1-year-old female-intact arctic fox (Vulpes lagopus) presented for diarrhea, lethargy, severe thrombocytopenia, and hyperbilirubinemia. Blood film evaluation revealed intracytoplasmic coccoid bacteria within moderate numbers of leukocytes consistent with infection by a rickettsial organism. Similar organisms were observed within many leukocytes from fine-needle aspirates of an enlarged peripheral lymph node. The lymph node also contained moderate necrosis and an expansion of granular lymphocytes. Parasitic ovum consistent with the trematode Nanophyetus salmincola was found on fecal floatation. The patient responded to treatment with doxycycline, enrofloxacin, ampicillin/sulbactam, and other supportive therapies. Polymerase chain reaction testing confirmed the presence of Neorickettsia sp., and DNA sequencing identified the organism as Stellantchasmus falcatus agent. To the authors' knowledge, this is the first report describing this organism microscopically in peripheral blood, the first reported case of infection in this species of canid, and describes the various clinicopathologic changes with this infection.

Klebsiella species, particularly Klebsiella pneumoniae, are among the most frequently isolated Gram-negative pathogens in surgical departments, associated with a growing trend in multidrug resistance. To identify the types of infections caused by Klebsiella spp. in a general surgery department and to analyze their antimicrobial susceptibility patterns. This retrospective observational study includes bacteriological cultures collected from surgical inpatients between October 2016 and December 2024. Only cases with confirmed Klebsiella spp. isolation were included. Specimen types, infection categories, and antibiotic susceptibility profiles were extracted and analyzed. A total of 138 Klebsiella-positive cultures were identified. Clinical characteristics were analyzed in 38 patients with complete records. The most common infection types included surgical site infections (SSIs), intra-abdominal infections, and biliary tract infections. Sensitivity was highest to carbapenems, while marked resistance was observed to ampicillin-sulbactam and third-generation cephalosporins. Some isolates exhibited ESBL or carbapenemase-producing phenotypes. Reported colistin non-susceptibility was elevated in our cohort; however, these results should be interpreted cautiously because the reference broth microdilution method was not systematically documented. The findings underscore the importance of local surveillance of Klebsiella spp. in surgical settings to info rm empirical treatment and control the spread of multidrug-resistant organisms.

Severe generalized tetanus causes autonomic dysfunction with hemodynamic instability. While thromboembolic and hemorrhagic complications are recognized, cerebral infarcts secondary to tetanus-related dysautonomia have not been documented. A previously healthy 79-year-old unvaccinated woman presented with trismus and neck stiffness and was diagnosed with severe generalized tetanus. She received human tetanus immunoglobulin, tetanus toxoid, and intravenous metronidazole, and was intubated and managed in the ICU under deep sedation. She developed severe dysautonomia requiring vasopressors. Fever on day 6 was attributed to ventilator-associated pneumonia, treated with ampicillin-sulbactam for seven days; sepsis and infective endocarditis were excluded. Subcutaneous heparin calcium was administered for deep vein thrombosis (DVT) prophylaxis from day 1, and was switched to edoxaban on day 14 for both prophylaxis and treatment of internal jugular vein thrombosis. Neuroimaging after ICU transfer revealed asymptomatic multiple cerebral infarcts presumed to result from hemodynamic instability. A left iliopsoas hematoma was incidentally identified on day 21, leading to edoxaban discontinuation. Thereafter, no pharmacological treatment was administered for the hemodynamic stroke or iliopsoas hematoma. Follow-up MRI examinations demonstrated progressive improvement in imaging findings. The patient underwent rehabilitation and was transferred to a rehabilitation facility on day 51. A literature review revealed that iliopsoas hematoma occurs in approximately 20% of patients with tetanus, yet remains underrecognized by physicians. This is the first documented case of tetanus complicated by cerebral infarction suggestive of hemodynamic stroke. Physicians should be aware that severe tetanus-related dysautonomia may cause cerebral infarction, and that iliopsoas hematoma may represent a disease-related complication.

Background: Uropathogenic Escherichia coli (UPEC) is the primary etiological agent of urinary tract infections (UTIs) worldwide. The emergence of strains combining high virulence with multidrug resistance (MDR) poses a significant challenge to public health. This study aimed to characterize the phylogenetic distribution, virulence profiles, and antimicrobial susceptibility of UPEC isolates recovered from patients in the metropolitan area of Buenos Aires (AMBA), Argentina. Methodology: Phylogenetic groups, the ST131 lineage, and virulence-associated genes were identified using PCR-based assays. Antimicrobial susceptibility testing (AST) was performed using automated methods and extended-spectrum beta-lactamase (ESBL) production was confirmed using the double-disk synergy test. Colistin (COL) resistance was evaluated by Colistin Drop Test and PCR screening for the mcr-1 (mobile colistin resistance gene 1). Biofilm formation was detected by the Tissue Culture Plate (TCP) method, whereas phenotypic virulence factors (VF) were assessed with Congo Red agar, hemagglutination, and hemolysis assays. Results: Phylogenetic groups B2 (43.8%) and D (26.7%), typically associated with extraintestinal infections, were the most frequent. The high-risk clone B2-ST131 was detected in 6.7% of isolates. Biofilm production was observed in 92.4% of the isolates, with curli fimbriae (87.6%) being the most frequently expressed VF. The highest resistance rates were observed for ampicillin (62.1%), ampicillin-sulbactam (39.8%), and trimethoprim-sulfamethoxazole (25.2%). Interestingly, 3.8% of isolates exhibited colistin resistance, despite the absence of the mcr-1 gene. Conclusions: This study highlights the detection of MDR-UPEC isolates that showed strong resistance to fluoroquinolones and were ESBL producers with high virulence in Argentina, justifying future research encompassing genomic and epidemiological monitoring of local UPEC, which is essential for managing infections and developing new therapeutic and preventive measures.

Multidrug-resistant Salmonella has been classified as a pathogen of high priority. However, limited or mixed-quality studies reported multidrug-resistant Salmonella strains from pediatric patients. The study aimed to investigate the prevalence, serotypes, antimicrobial characteristics, and plasmid profiles of clinical Salmonella strains isolated from pediatric patients. For that, we collected 46 Salmonella isolates from children's fecal samples in multiple hospitals. Antimicrobial susceptibility testing, conjugation assay, short-read and long-read sequencing, and bioinformatics analysis were performed. Our data revealed that the top three serotypes of the 46 isolated strains are Salmonella I 4,[5],12:i:-, Typhimurium, and Enteritidis, with prevalence at 34.78% (16/46), 23.91% (11/46), and 17.39% (8/46), respectively. Most of these strains clustered into ST34, ST19, and ST11. Antimicrobial susceptibility testing analysis suggested that more than 80% of these Salmonella isolates belong to multidrug-resistant strains, all of them showed resistance to ampicillin, ampicillin-sulbactam, and trimethoprim-sulfamethoxazole, and all strains were susceptible to meropenem, with about 17.39% of them having minimum inhibitory concentrations ≥4 µg/mL to imipenem. Moreover, conjugation assay and long-read sequencing analysis on the plasmids harbored in 12 of the 46 Salmonella strains consistently showed that none of them has intact conjugative transfer genes, indicating Salmonella strains from pediatric patients have different antimicrobial resistance levels and impaired plasmid transferability due to loss of part or whole tra genes.IMPORTANCESalmonella, one of the world's top prevalent foodborne pathogens, has gained resistance to fluoroquinolone and many other drugs that are used clinically. However, few studies focused on the genomic and plasmid profiles of multidrug-resistant Salmonella isolates from pediatric patients. In the present report, our data indicate that Salmonella strains isolated from pediatric patients have different antimicrobial resistance levels and plasmid transferability compared to those from adults. These findings provide crucial insights into pediatric patients' isolated Salmonella strains from Zhuhai, China, which can be leveraged to optimize drug regimens, leading to more effective and less toxic treatments for pediatric infections, and call for more attention to Salmonella epidemiology and antimicrobial resistance patterns in children.

Enterococcus faecalis is a gram-positive, facultative anaerobic bacterium that commonly colonizes the gastrointestinal and genitourinary tracts. Although frequently implicated in urinary tract infections and bacteremia, it is also a well-recognized cause of subacute infective endocarditis. We present a case of subacute infective endocarditis caused by Enterococcus faecalis, initially masked by presumed urinary sepsis in a patient who had undergone transurethral resection of the prostate (TURP) less than two months prior. The patient presented with four days of fever and generalized weakness, accompanied by clinical features of sepsis and urinalysis findings suggestive of urinary tract infection, indicating a possible urinary source. Empiric broad-spectrum antibiotic therapy was initiated for presumed urinary sepsis. However, persistent symptoms despite three days of treatment prompted further evaluation. Blood cultures grew Enterococcus faecalis, while urine cultures remained negative, raising suspicion for an alternative source of infection. After excluding intra-abdominal pathology through contrast-enhanced abdominopelvic computed tomography (CT), transthoracic echocardiography revealed mitral valve vegetation consistent with infective endocarditis. Targeted antimicrobial therapy with vancomycin for 14 days and ampicillin-sulbactam for 30 days resulted in complete clinical recovery and resolution of valvular vegetation without the need for surgical intervention. This case highlights the importance of maintaining a high index of suspicion for infective endocarditis in patients with Enterococcus faecalis bacteremia, particularly when no clear infectious focus is identified. Additionally, it underscores the potential association between TURP-related bacteremia and subsequent endocarditis. These findings emphasize the need to reassess and optimize perioperative prophylactic strategies in patients undergoing urological procedures, taking into account regional antibiotic resistance, in order to reduce the risk of severe systemic complications such as infective endocarditis.

This study investigated the occurrence of antibiotic-resistant Shigella spp. within a dairy farm environment by examining 200 samples collected from cattle (milk, faeces), environmental sources (drinking water, dairy wastewater, milking machine swabs), and human handlers. Shigella spp. was detected in 8.5% of samples, with the highest occurrence in dairy wastewater (52.94%) and feces (35.29%). S. flexneri was the predominant species identified, while S. dysenteriae and S. sonnei were less frequent. Notably, no Shigella spp. were found in milk or handler swabs. High antibiotic resistance was observed, with complete resistance to ampicillin (100%), followed by tetracycline (82.4%) and cefoxitin (58.8%). Conversely, isolates were largely susceptible to meropenem (94.1%), ampicillin-sulbactam (94.1%), and cefepime (88.2%). Multidrug resistance (MDR) was common, affecting 70.6% of isolates. Phenotypic tests confirmed extended-spectrum β-lactamase (ESBL) production in ten isolates and AmpC production in eight cefoxitin-resistant isolates. The multiple antibiotic resistance (MAR) index was ≥ 0.2 in 94.1% of isolates. Genotypic analysis revealed a high prevalence of tetracycline resistance genes (tetA, tetB; 70.5%), plasmid-mediated quinolone resistance genes (qnrS, qnrB; 58.8%), and blaAmpC gene (52.9%). ESBL genes (blaTEM-1, blaSHV-1, blaCTX-M-9) were present in 17.6% of isolates, while the trimethoprim resistance gene (dfrA17) was detected in 5.8%. Chi-square analysis confirmed significant differences in prevalence, resistance profiles, and gene distribution (p < 0.05). These findings highlight the occurrence of multidrug-resistant Shigella spp. within the dairy farm ecosystem, underscoring their potential role in the dissemination of antibiotic resistance and posing an emerging public-health concern.

Carbapenem-resistant Acinetobacter baumannii (CRAB) represents a formidable nosocomial pathogen, with healthcare environments acting as critical reservoirs for its dissemination. In this study, we investigated the prevalence, antimicrobial resistance profiles and genomic characteristics of CRAB isolates collected from hospitals in Shanghai, China, between June and December 2024, identifying ST2[Pas] (84.13%) and ST164[Pas] (15.08%) as the predominant lineages among the 126 CRAB isolates recovered from clinical (n=94), environmental (n=29) and healthcare worker (n=3) sources. Environmental CRAB accounted for the highest proportions on patient-contact surfaces (34.48%), medical devices (31.03%) and shared items (24.14%). Within the dominant ST2[Pas] lineage, clinical isolates exhibited higher resistance rates to ampicillin/sulbactam, cefoperazone/sulbactam and levofloxacin, with significantly higher carriage rates of bla TEM-1D compared to environmental isolates. Compared to ST164[Pas], ST2[Pas] CRAB isolates exhibited greater resistance to amikacin, gentamicin, trimethoprim/sulfamethoxazole and minocycline and a higher prevalence of aph(3')-Ia, aph(3″)-Ib, aph(3')-VI, aph(6)-Id, armA, bla OXA-66 , bla TEM-1D, mph(E) and tet(B), but lower rates of bla CARB-16, bla NDM-1 and bla OXA-91 (P<0.05). Notably, comparative genomic analysis suggested putative adaptive differences between the two lineages. ST2[Pas] retained the T6SS and biofilm-associated genes (bap), descriptive genomic features that suggest a potential capacity for active colonization. Conversely, the ST164[Pas] clone lacked the T6SS gene cluster but was enriched with the surface adhesin ata and immune evasion-related genes. Concordantly, ST164[Pas] CRAB isolates exhibited significantly stronger biofilm-forming capacities than ST2[Pas] in vitro. We hypothesize that these genomic alterations and phenotypic traits may represent a fitness trade-off, potentially conferring a survival advantage under antibiotic pressure. Furthermore, bla OXA-23 in ST2[Pas] was predominantly carried on conjugative plasmids restricted to Acinetobacter species, whereas bla NDM-1 in ST164[Pas] was localized on a broad-host-range non-mobile plasmid, potentially facilitating cross-genus transmission. Although our ST164[Pas] isolates shared high homology with clinical strains from Zhejiang, China, the genomic localization of bla NDM-1 differed between the plasmid and chromosome, respectively. These descriptive genomic findings highlight the putative adaptive trajectories of the predominant ST2[Pas] and emerging ST164[Pas] clones, underscoring the critical need for comprehensive genomic surveillance, complemented by future phenotypic validation, to monitor their rapid evolution and dissemination.

Background/Objective: Acinetobacter baumannii is an opportunistic pathogen responsible for various healthcare-associated infections, particularly in critically ill patients. The emergence and rapid spread of multidrug- and extensively drug-resistant strains, notably carbapenem-resistant A. baumannii (CRAB), threaten global health. We aimed to investigate the clonal distribution, antimicrobial resistance profiles, and resistance determinants of CRAB bloodstream isolates in Korean hospitals to identify emerging high-risk clones and their potential clinical impact. Methods: Sequence types (STs) were determined using the Oxford multilocus sequence typing scheme, and antimicrobial susceptibility profiles and resistance determinants were evaluated. Results: We analyzed 812 CRAB bloodstream isolates collected from nine South Korean tertiary hospitals between 2016 and 2020. The isolates were classified into 39 STs, with ST191 (n = 245) and ST369 (n = 192) being the most prevalent. Between 2016 and 2020, ST369 increased from 2.6% to 37.9%, while ST195, first detected in 2018 (0.5%), increased to 19.0%; however, ST191 declined from 45.2% to 19.0%. Most CRAB infections were hospital-acquired (91.6%, 744 of 812), predominantly affecting men aged ≥51 years, particularly the 71-80-year-olds. Resistance rates were ≥80% for ampicillin-sulbactam and ciprofloxacin. blaOXA-23 was detected in 807 isolates, confirming its central role in carbapenem resistance. ST195 exhibited higher resistance to minocycline (29.4%) than did the other STs. Conclusions: Dynamic clonal shifts and high antimicrobial resistance exist among CRAB isolates in Korean hospitals, with the rapid emergence of ST195 and ST369 increasing clinical challenges. Continuous epidemiological surveillance and targeted infection control measures are essential to control the spread of high-risk CRAB clones.