Antibiotics-Basel最新文献

Background/Objectives: The deposition of antibiotic residues in animal source foods has become a global public health threat. This study aimed to assess antibiotic class residues in raw cow milk from smallholder dairy farms in Mbala and Kasama, Zambia. Methods: A cross-sectional study was conducted, in which 93 milk samples (54 from Mbala and 39 from Kasama) were randomly collected from lactating cows on 56 farms between May and June, 2025. The samples were analyzed using the Charm II assay for beta-lactams, tetracyclines, macrolides, sulfonamides, and aminoglycosides. A total of 100 mL of milk was collected in sterile plain tubes, placed in a cooler box with ice packs, and transported to the district laboratory's freezer and then delivered to the Central Veterinary Research Institute at (-18 to -20 °C), where they were stored at -20 °C. Statistical significance between districts was determined using Pearson's chi-square, and associations between a district and the occurrence of antibiotic residues in milk were evaluated using logistic regression. Data were analyzed using Stata 14.2 at a 95% confidence level (p = 0.05). Results: A total of 91.4% (n = 85) of samples had antibiotic residues above EU/MRLs, with mean positive samples being 0.91 ± 0.28 and a significant association between a district and residue occurrence (OR = 0.086; p = 0.025). Approximately 44.1% of the samples had multiple antibiotic residues. Approximately 82.1% of samples from Kasama and 98.1% from Mbala had antibiotic residues (p = 0.006). Approximately 68.8% of samples had sulphonamides, and 58.1% macrolides, indicating their widespread use. Tetracyclines were 12.9%, beta-lactams 9.7%, and aminoglycosides 2.2%. Conclusions: A majority of milk samples had antibiotic residues above EU/MRLs, raising public health threats and necessitating the development and implementation of policies.

Background/Objectives: Salmonella enterica is a major cause of foodborne infection globally, with poultry acting as an important reservoir. However, data from Central Asia remain limited. This study provides preliminary phenotypic and genomic characterization of S. enterica isolates recovered from poultry farms in southern Kazakhstan, focusing on antimicrobial resistance (AMR), serotypes/sequence types and phylogenetic relationships. Methods: In October 2024, 335 poultry and environmental samples were collected from three regions of southern Kazakhstan using a cross-sectional, detection-focused sampling strategy. Isolation of Salmonella enterica followed enrichment and selective culturing, with confirmation by biochemical assays, slide agglutination serology and real-time PCR. Antimicrobial susceptibility testing was performed using the Kirby-Bauer disk diffusion method and interpreted according to CLSI veterinary breakpoints (VET01/VET08) and CLSI M100 where veterinary criteria were unavailable. Whole-genome sequencing (Illumina) was used for in silico serotyping, MLST, AMR gene detection, plasmid replicon typing and SNP-based phylogenetic reconstruction. Results: Nine S. enterica isolates were confirmed (overall yield 2.7%; 9/335), comprising S. Enteritidis (ST11; n = 4), S. Infantis (ST32; n = 3) and ST68 (n = 2; Choleraesuis/Paratyphi C lineage). All isolates were resistant to ciprofloxacin, and most displayed resistance to ampicillin, gentamicin and trimethoprim-sulfamethoxazole. Plasmid-associated AMR determinants, including blaTEM-116, tet(A), sul1 and dfrA14, were frequently identified on IncF-type replicons. Phylogenetic analysis revealed that the isolates clustered with previously described Eurasian poultry-associated lineages. Conclusions: In this small, exploratory sample from poultry farms in southern Kazakhstan, all recovered S. enterica isolates were multidrug-resistant, with universal fluoroquinolone resistance and frequent plasmid-borne AMR genes. These preliminary findings provide baseline genomic evidence and highlight the need for broader, harmonized AMR surveillance in the regional poultry sector.

Objectives: Inappropriate antibiotic prescribing for acute upper respiratory tract infections (URTIs) is a significant problem in emergency departments (EDs) worldwide. In this study, we separately evaluated the effectiveness of physician feedback and patient education in reducing antibiotic prescribing for URTIs in the ED setting. Methods: We conducted a quasi-experimental study across four large adult EDs in Singapore from January 2021 to December 2023. After a baseline period (18 months), two EDs were randomly assigned to either implement physician feedback or patient education for six months (intervention period 1), and all EDs subsequently implemented both interventions in the next six months (intervention period 2). Hierarchical segmented logistic regression was used to assess the effectiveness of the interventions in reducing weekly antibiotic prescribing for URTIs. Results: In the two EDs that implemented physician feedback first, there was a significant decrease in the trend of weekly antibiotics prescribed (AOR 0.981 [95% CI (0.964, 0.998)]) compared to the last 6 months of the pre-intervention period. Adding patient education in the next phase (intervention period 2) did not further reduce the trend of weekly antibiotics prescribed. For the second group of two EDs that implemented patient education first, there was no significant reduction in the weekly antibiotic prescribing trend during intervention period 1. With the addition of physician feedback, a significant decline in the trend of weekly antibiotics prescribed was observed in intervention period 2 (AOR 0.921 [95% CI (0.903,0.940)]). Conclusions: Physician feedback alone can reduce antibiotic prescribing for URTIs in EDs. Further research is warranted to assess the effectiveness of patient education involving multi-modal educational channels co-created with patients.

Background/Objectives: Antimicrobial resistance (AMR) in companion animals is a growing One Health concern due to the close interaction between pets and humans. Staphylococcus aureus (S. aureus) and Staphylococcus schleiferi (S. schleiferi) are common colonizers of the canine ear canal and can act as reservoirs of resistance. This study aimed to assess the prevalence and antimicrobial resistance profiles of S. aureus and S. schleiferi isolated from dogs with otitis externa and clinically healthy dogs in western Romania. Methods: A total of 973 canine ear swabs were collected, 503 from dogs with otitis externa and 470 from healthy dogs. Isolates were identified using MALDI-TOF MS. Antimicrobial susceptibility testing was performed using the VITEK^® 2 Compact system, bioMérieux, Marcy-l'Étoile, France, and interpreted according to CLSI VET01 guidelines, with 13 antimicrobials representing multiple drug classes. Results: S. aureus was more prevalent in healthy dogs (20%) than in otitis cases (4%), while S. schleiferi was more common in otitic samples (7.5% vs. 4%). Among S. aureus isolates from otitic dogs, penicillin resistance was highest (65%), and 25% were multidrug-resistant (MDR). In healthy dogs, S. aureus showed 54.3% penicillin resistance and 16% MDR prevalence. Four MRSA strains (4.3%) were identified only in healthy dogs. S. schleiferi exhibited the highest resistance to clindamycin, with MDR rates of 10.6% in otitic and 5.6% in healthy dogs. No MRSS strains were detected. Conclusions: Clinically healthy dogs may serve as asymptomatic carriers of resistant Staphylococcus strains, including MRSA. Routine antimicrobial susceptibility testing is essential to inform treatment choices and mitigate resistance dissemination within veterinary and public health contexts.

Background/objectives: Antimicrobial resistance (AMR) is a major global health threat. In patients undergoing cataract surgery, AMR complicates infection control, particularly efforts to reduce the risk of endophthalmitis-a rare but severe postoperative complication. This article reviews country-specific strategies for endophthalmitis prevention, focusing on antimicrobial use.

Methods: Ophthalmology experts from 10 countries contributed national perspectives on infection prevention. Official guidelines served as the primary basis for analysis; when unavailable, expert opinion and routine clinical practice were considered.

Results: Routine preoperative antibiotic use is uncommon in 6 out of 10 countries. Instead, artificial tears and bacteriostatic or bactericidal treatments are frequently employed. One country allows optional antibiotic use, while 3 include it in routine preoperative care. For intraoperative management, antisepsis with 5-10% povidone-iodine is standard practice in 9 countries. Intracameral cefuroxime (typically 1 mg/0.1 mL) is widely used in 7 countries and considered essential in most countries. Postoperatively, broad-spectrum topical antibiotics, primarily fluoroquinolones, are typically prescribed, often as fixed-dose combinations with corticosteroids (8 countries), although duration and regimens vary.

Conclusions: Despite national differences, povidone-iodine, intracameral cefuroxime, and topical fluoroquinolones are widely used. Preoperative antibiotic use varies, while postoperative regimens are more consistent. These practices reflect local AMR patterns, regulations, and available healthcare resources. Although broad-spectrum agents are generally preferred, they raise concerns about resistance. Tailoring prophylactic strategies to local microbiological profiles and limiting the duration of antibiotic therapy are key to balancing efficacy and stewardship. An individualized, evidence-based approach is essential to reduce endophthalmitis risk and address AMR challenges.

Background: The increasing worldwide problem of bacterial infections caused by multidrug-resistant Gram-negative and Gram-positive pathogens has led to consideration of intravenous fosfomycin, especially in combination antimicrobial regimens. We performed a systematic review of the evidence from comparative and non-comparative studies of patients who received intravenous fosfomycin as monotherapy or in combination with other antibiotics. Methods: Relevant studies were sought in six resources (Cochrane Library, Google Scholar, PubMed Central, PubMed, Scopus, and Web of Science) and two registries [ClinicalTrials.gov and International Clinical Trials Registry Portal (ICTRP)]. Results: Of the 2351 screened articles, 53 (31 comparative and 22 non-comparative studies) reported relevant data for patients with infections at various sites caused by Gram-negative bacteria, including Enterobacterales, Pseudomonas aeruginosa, and Acinetobacter baumannii, and Gram-positive bacteria, including Staphylococcus spp. and enterococci. Intravenous fosfomycin, either as monotherapy or combination therapy, showed similar or, in some studies, better efficacy (clinical and microbiological cure) compared to therapy with antimicrobial agents not including fosfomycin. The data evaluated also suggest that intravenous fosfomycin has a good safety profile. The administration of the antibiotic may be associated with electrolyte imbalances, especially hypokalemia and hypernatremia. These adverse events may be prevented and controlled with appropriate therapeutic measures and rarely lead to the discontinuation of the drug. Conclusions: Overall, the considerable body of published data suggests that intravenous fosfomycin is safe and effective. The antibiotic may be considered for patients with both Gram-positive and Gram-negative infections, especially in critically ill patients and/or deep-seated infections. The heterogeneity of the included studies is a limitation that prevents firm conclusions.

Background: Whether nanoengineered titanium surfaces confer superior implant stability beyond modern microrough controls remains uncertain.

Methods: This systematic review followed PRISMA 2020 guidance: comprehensive multi-database searching with de-duplication; dual independent screening, full-text assessment, and standardized data extraction for predefined outcomes (implant stability quotient [ISQ], mechanical anchorage by removal/push-out/pull-out torque, and histologic bone-to-implant contact). Risk of bias was appraised with RoB 2 for randomized trials, ROBINS-I for non-randomized clinical studies, and CAMARADES (animal experimentation). The certainty of clinical evidence was summarized using GRADE.

Results: Across animal models, nanoengineered surfaces consistently improved early osseointegration indices (higher removal torque and bone-to-implant contact at initial healing). In clinical comparative studies, nanoengineered implants showed modest, time-limited gains in early stability (ISQ) versus microrough titanium. By 3-6 months, between-group differences typically diminished, and no consistent advantages were demonstrated for survival or marginal bone outcomes at later follow-up. Methodologic heterogeneity (surface chemistries, timepoints, outcome definitions) and small clinical samples limited quantitative synthesis. Overall, risk-of-bias concerns ranged from some concerns to high in non-randomized studies; the certainty of clinical evidence was low.

Conclusions: Nanofeatured titanium surfaces improve early osseointegration but do not demonstrate a consistent long-term advantage over modern microrough implants. Current evidence supports an early osseointegration benefit without clear long-term clinical advantage over contemporary microrough implants. Adequately powered, head-to-head trials with standardized stability endpoints and ≥12-month follow-up are needed to determine whether early gains translate into patient-important outcomes.

Background/Objectives: Subclinical mastitis is a common and economically significant infection in dairy cows. This study aimed to assess the prevalence and antimicrobial susceptibility of bacteria causing subclinical mastitis in dairy cows in the Upper Cheliff Region, Northern Algeria, and to investigate the effects of subclinical mastitis on milk production and reproductive performance. Methods: A total of 263 cows from 23 farms were screened for subclinical mastitis using the California Mastitis Test (CMT) and sampled for isolation and identification of bacteria by MALDI-TOF MS. Antimicrobial susceptibility testing (AST) was performed using the Vitek 2 system and disk diffusion method. Methicillin resistance in staphylococci and mammaliicocci was confirmed by mecA/mecC detection. Results: The results revealed a prevalence of subclinical mastitis of 58.9% at the cow-level and 31.1% at the quarter-level. The most prevalent microorganisms identified were Enterococcus faecium (E. faecium) (24.4%) and Enterococcus faecalis (E. faecalis) (20.5%), followed by non-aureus staphylococci (NAS) (16.9%), Escherichia coli (E. coli) (7.9%) and Staphylococcus aureus (S. aureus) (7.08%). Risk factors significantly associated with the prevalence of subclinical mastitis included parity, lower milk production (<12 L/day), poor animal cleanliness and a history of previous mastitis. Reproductive performance was significantly impaired in cows with subclinical mastitis, cows with longer calving-to-first-service intervals (130 vs. 102.7 days; p < 0.0001), more services per conception (2.5 vs. 1.9; p < 0.0001) and a lower pregnancy rate at first service (24.5% vs. 48.1%; p < 0.0001). Furthermore, 43.2% of cows with subclinical mastitis required three or more inseminations to achieve pregnancy. AST showed a low resistance rate for the antimicrobial agents most commonly used in human and veterinary medicine. Coagulase-negative staphylococci (CoNS) showed remarkable rates of methicillin-resistance (22.2%), as well as resistance towards fosfomycin (37.8%) and tetracycline (31.1%). A substantial proportion of E. coli isolates exhibited resistance to piperacillin (40%) and ciprofloxacin (15%). All S. aureus isolates were classified as MSSA without detection of mecA and mecC genes. Conclusions: The results of this study demonstrated that subclinical mastitis is prevalent in the Upper Cheliff region and is associated with reduced milk production and reproductive performance. The detection of pathogenic and resistant microorganisms in milk is alarming and requires effective management strategies to control subclinical mastitis and improve dairy farm productivity.

Background: Infections caused by antimicrobial-resistant bacteria are difficult to treat and increase the risk of death in animals. This report describes a fatal case of diarrhea in a horse that, despite intensive treatment including surgery and broad-spectrum antimicrobials (ceftiofur and amikacin), experienced a worsening of its condition and subsequent death. Methods: A fecal swab sample was subjected to microbiological culture for the identification of bacteria and assessment of their phenotypical antimicrobial susceptibility profiles using the disk-diffusion and broth microdilution methods. The double-disk synergy test, polymerase chain reactions for the detection of genes encoding extended-spectrum β-lactamases, and whole-genome sequence-based analysis were also performed. Results: Strains of Salmonella enterica and Escherichia coli were isolated, with the E. coli strain DSL-HVUVV-2025 presenting resistance to a third-generation cephalosporin. Accordingly, the bla_CTX-M-2 gene was identified in the DSL-HVUVV-2025 strain, which was submitted to whole-genome sequencing. Genomic analysis showed several antimicrobial resistance determinants, as well as virulence genes, including those associated with the enteroaggregative pathotype. The bla_CTX-M-2 gene was surrounded by an ISCR1 element and embedded in a complex class 1 integron that is part of the Tn7337 transposon. Strain DSL-HVUVV-2025 belonged to a novel sequence type. Conclusions: This case highlights the importance of monitoring antimicrobial resistance and performing genomic characterization of bacteria involved in equine diarrhea to guide effective clinical management in veterinary hospitals. It also reinforces the role of horses as potential carriers of WHO critical priority pathogens and the need for responsible antimicrobial use.

Background: Carbapenem-resistant Acinetobacter baumannii (CRAB) is a critical public health threat, particularly in hospital environments where treatment options are limited. Drug repurposing offers a rapid and cost-effective strategy to address antimicrobial resistance. This study evaluates KP46 (tris(8-quinolinolato)gallium(III)), an orally bioavailable gallium-based anticancer agent, for its antimicrobial potential against CRAB. Methods: KP46 was synthesized and characterized using spectroscopic and crystallographic techniques. Its antibacterial activity was assessed against planktonic and biofilm-associated CRAB strains, including multidrug-resistant clinical isolates. Mechanistic studies included intracellular reactive oxygen species (ROS) quantification, membrane integrity assays, and resistance development profiling. Results: KP46 exhibited potent antibacterial activity against both susceptible and carbapenem-resistant A. baumannii strains. It inhibited planktonic growth and disrupted early biofilm formation. KP46 induced intracellular oxidative stress, leading to membrane damage and cell death. Resistance development was significantly slower compared to meropenem, and KP46 retained efficacy against meropenem-resistant isolates. Conclusions: KP46 demonstrates dual-action antimicrobial activity and a low propensity for resistance development, positioning it as a promising candidate for repurposing against CRAB infections. These findings support further preclinical evaluation of KP46 as an orally active therapeutic agent targeting both planktonic and biofilm-associated bacterial populations. resistance development and retained efficacy against meropenem-resistant strains.