The objective of this work was to identify and characterise the causative agent(s) of an atypical septicaemic syndrome in 3- to 6-month-old calves. Nine cattle from three Scottish dairy farms were subject to post-mortem in 2020 and 2021, and tissue samples were screened via routine bacteriology. Escherichia coli was isolated from all sampled tissues and a representative isolate from each calf was taken forward for whole-genome sequencing for strain typing, identification of putative virulence factors and antimicrobial resistance genes, and assessment of phylogenetic relationships with other sequenced strains. The nine E. coli isolates were highly-related, being separated by a maximum of 5 single nucleotide polymorphisms. The isolates were serotyped in silico as O78, H9 and were multilocus sequence typed as ST23. Further analysis revealed 13 virulence genes, with the most frequent being associated with serum survival, cytotoxic protein and haemolysin production, and iron transport. These strains encode a novel fimH variant - designated fimH-1571 - which has a mutation potentially linked to increased adherence and invasion. Phylogeny and virulence gene profile indicate an avian pathogenic-like E. coli within a poultry lineage, however there were no poultry units in the vicinity of these farms. Ampicillin, amoxicillin, streptomycin and tetracycline resistance was predicted from their genome sequences, which agreed with phenotypic antimicrobial susceptibility testing. In conclusion, while not demonstrated here, these data are consistent with a transmission event between cattle units (or a common source) and suggest the possible emergence of virulent avian pathogenic-like E. coli in cattle for which future surveillance is merited.

Background and objectives The Salmonella strains causing bloodstream infection show wide genetic diversity together with different antibiotic resistance profiles worldwide. The response of typhoidal Salmonella to standard antimicrobial treatments has become increasingly concerning during the past few decades. This study was conducted to evaluate the occurrence rate, antibiotic susceptibility patterns, and clinical characteristics of patients with Salmonella bacteraemia in a tertiary care hospital in Pune, Maharashtra, India. Methods A cross-sectional study was conducted from March 2024 to March 2025, analysing blood culture-confirmed cases of enteric fever. All patients with Salmonella-positive cultures were included, and data were gathered from clinical and microbiology records. Results Out of 6,862 blood cultures processed, 42 (0.6%) tested positive for Salmonella species. Of these, 50% were Salmonella Typhi, 36% were Salmonella Paratyphi A, and the remaining 14% included S. Cholerasuis, S. Typhimurium, and S. Gallinarum. All S. Typhi and S. Paratyphi A isolates were fully susceptible to first-line antibiotics, including chloramphenicol, amoxicillin, and co-trimoxazole, as well as to ceftriaxone and cefixime. However, 78.5% of isolates showed reduced susceptibility to ciprofloxacin. Initial disc diffusion testing suggested potential azithromycin resistance in 11 isolates, but confirmatory E-strip testing found none to be resistant based on MIC values. One S. Paratyphi A isolate exhibited a notably high MIC of 24 µg/mL, which is not classified as resistant according to U.S. NARMS guidelines. Interpretation and conclusions The increasing azithromycin MIC values among typhoidal Salmonella indicate potential resistance development, so additional research should assess azithromycin susceptibility patterns in detail.

Antibiotic residues in aquatic environments are an increasing concern because they may retain antibacterial activity, promote antibiotic resistance and generate transformation products with uncertain ecological risks. In this study, marine-derived bacteria were screened for their ability to degrade representative β-lactam antibiotics. Strain PP1, identified as Bacillus cereus, was selected for detailed characterization because of its outstanding degradation capacity toward piperacillin, ceftiofur and cephalexin, especially its efficient removal of piperacillin at a high initial concentration of 100 mg/L. During a 48-h incubation, B. cereus PP1 completely degraded piperacillin and reduced the antibacterial activity of the treated solution against representative Gram-negative and Gram-positive bacteria. UHPLC-MS/MS analysis indicated that piperacillin was transformed mainly through β-lactam ring opening, together with side-chain cleavage and downstream fragmentation reactions. The degradation products showed no obvious hemolytic activity under the tested conditions, whereas live PP1 exhibited hemolysis, highlighting the need for biosafety evaluation before live-cell application. Whole-genome sequencing revealed that PP1 contains a single circular chromosome of 5,285,738 bp and has broad metabolic potential. CARD, CAZy and VFDB annotations indicated antibiotic tolerance, hydrolytic enzyme resources and virulence-associated features. Targeted mining using a local β-lactamase database identified two candidate β-lactamase genes, PP1_BLA_A and PP1_BLA_B, assigned to class A and class B β-lactamases, respectively. Structure prediction and molecular docking further suggested that both enzymes can accommodate piperacillin, but with distinct binding modes. These findings indicate that B. cereus PP1 is a valuable source for β-lactamase discovery and enzyme-based β-lactam bioremediation.

Urinary tract infections (UTIs) are a common indication for antibiotic use among adult outpatients in low- and middle-income countries, yet data on community-acquired UTIs (CA-UTIs) and antimicrobial resistance at primary healthcare facilities remain limited. A facility-based cross-sectional study was conducted from May to August 2024 at Igoma and Buzuruga Health Centres in Mwanza, Tanzania. Symptomatic adults without hospitalization within the preceding 30 days or urinary catheterization were enrolled. Clinical and demographic data were collected, and midstream urine specimens were cultured, followed by antimicrobial susceptibility testing using the disc diffusion method. Of 1,005 participants, the median age was 32 years [IQR: 23-49], 727 (72.3%) were female, and 64.3% reported to have been diagnosed with UTI within the previous six months. The median symptom duration before presentation was 8 days [IQR: 5-15]. Culture-confirmed UTI was detected in 221 participants (22.0%; 95% CI: 19.5-24.7), with Escherichia coli (32.9%) and Staphylococcus aureus (24.7%) being the most frequently isolated pathogens. Only 35.7% of culture-confirmed cases are presented with classic urinary symptoms of dysuria, frequency, or urgency. E. coli showed high resistance to ampicillin (93.4%), ciprofloxacin (62.3%), trimethoprim-sulfamethoxazole (60.7%), amoxicillin-clavulanic acid (57.4%), and tetracycline (55.7%); 82.8% were multidrug-resistant and 20.3% exhibited extended-spectrum beta-lactamase phenotypes. Among S. aureus isolates, 64.6% were cefoxitin-resistant, indicating methicillin resistance. CA-UTIs therefore constitutes a substantial burden among adult primary-care outpatients, accompanied by high antimicrobial resistance and frequent atypical clinical presentations. Improved access to UTI diagnostics, strengthened antimicrobial stewardship, and locally informed treatment guidelines are needed, particularly given the high resistance to commonly used empirical antibiotics.

Salmonella spp. remain an important cause of bacterial gastrointestinal infection, but local data from maternal and child healthcare hospitals remain limited. This retrospective study analyzed Salmonella spp. isolated from fecal cultures of inpatients at Longgang District Maternity and Child Healthcare Hospital of Shenzhen City from 2021 to 2025. Fecal specimens were processed using routine selective culture procedures; isolates were identified with the VITEK 2 Compact system, with VITEK MS confirmation when required, and antimicrobial susceptibility was interpreted according to Clinical and Laboratory Standards Institute (CLSI) M100, 35th edition. Annual positivity and non-duplicate isolation rates were compared using Pearson χ[2] tests. A total of 106 non-duplicate isolates were recovered, including 98 from pediatric inpatients. Annual positivity and non-duplicate isolation rates differed significantly across the 5-year study period (both P < 0.001) and were highest in 2025. Among pediatric cases, children aged 1-3 years accounted for 79.6%, with the 12 to <24-month group accounting for 52.0%. Resistance was high to ampicillin (76.7%), ampicillin/sulbactam (63.3%), trimethoprim-sulfamethoxazole (46.6%), and ceftriaxone (36.9%). Resistance to ciprofloxacin and levofloxacin was 12.5% and 14.8%, respectively, although intermediate rates were high. Most isolates remained susceptible to piperacillin/tazobactam and carbapenems. These findings show a concentration of laboratory-detected Salmonella among children aged 1-3 years, particularly those aged 12 to <24 months, and substantial resistance to several commonly used agents, supporting continued local surveillance and susceptibility-guided antimicrobial use.