Search Results (318)

Blood culture remains the gold standard for identifying bloodstream infections caused by bacteria and fungi. Isolation of the culprit microorganism onto agar plates also facilitates antimicrobial susceptibility testing. The purpose of this study was to determine the contamination rates, pathogen profile, and antimicrobial resistance in a secondary healthcare setting in a two-year timeframe. In this study, data regarding blood cultures of the years 2023 and 2024 were retrospectively analyzed to address the above questions. Blood cultures were incubated for seven days before being discarded as negative. The percentage of positive blood cultures for both years was 14.3%. Most positive cultures contained Gram-positive cocci, with a prevalence of coagulase-negative Staphylococci. In descending order, 72.72% were coagulase-negative Staphylococci, 15.15% were Staphylococcus aureus, and 12.12% were Streptococci. One strain of S. aureus was methicillin-resistant (MRSA), and one strain of Enterococcus faecium was vancomycin-resistant (VRE). Of the Gram-negative rods, 78.3% were Enterobacterales. Of these, Escherichia coli, Klebsiella pneumoniae, and Proteus mirabilis were the top pathogens. The remainder comprised eight strains of Pseudomonas aeruginosa, four strains of Acinetobacter baumannii (one pandrug-resistant), three strains of Stenotrophomonas maltophilia, one strain of Sphingomonas paucimobilis, and one strain of Campylobacter jejuni. The isolated fungi comprised Candida parapsilosis, Candida glabrata, and Candida tropicalis. Of the isolated Escherichia coli strains, 39.5% were resistant to ciprofloxacin regardless of origin (outpatient or hospitalized patients). Outpatient samples were taken in a Hemodialysis Unit that collaborates with our laboratory, obtained from patients with fever or other signs of infection. Distinguishing true bacteremia from contamination remains challenging. The contamination rate in our study was quite high at 5.3%. Since there is no dedicated phlebotomy team in our healthcare setting, in light of our results, educational courses have been conducted to demonstrate the best practices for sample collection. Full article

Background/Objectives: Infectious keratitis represents a major ophthalmological emergency and a leading cause of corneal blindness worldwide. Rapid progression, frequent antimicrobial resistance, and poor therapeutic outcomes make genotypic surveillance essential. This study aimed to analyze the distribution of bacterial pathogens involved in infectious keratitis and characterize their resistance mechanisms at the genotypic level, with emphasis on extended-spectrum β-lactamase (ESBL) genes. Methods: Corneal scrapings were collected from patients diagnosed with bacterial keratitis at the County Clinical Emergency Hospital of Craiova. Isolates were identified using standard microbiological techniques, followed by antimicrobial susceptibility testing. Genotypic resistance markers, including tem, shv, and ctx-M gene families, were investigated using PCR-based methods, while phenotypic resistance was investigated using the Vitek2 system. Results: Gram-positive bacteria were the predominant isolates, with coagulase-negative staphylococci and Staphylococcus aureus accounting for most cases. Among Gram-negative pathogens, Pseudomonas aeruginosa and Enterobacteriaceae were frequently detected. Genotypic analysis revealed tem genes in a substantial proportion of ocular isolates, often plasmid-mediated, while shv genes showed low prevalence and ctx-M genes were less frequent. The genetic determinants correlated well with phenotypic resistance expressed by MICs. Conclusions: The study highlights the significant correlation between genotypic markers and resistance phenotypes in bacterial keratitis. Continuous molecular surveillance is essential to guide targeted therapy, prevent therapeutic failure, and improve patient outcomes in infectious keratitis. Full article

Wastewater-based surveillance (WBS) is valuable for monitoring antimicrobial resistance (AMR). Staphylococci are key targets, as wastewater can facilitate gene transfer and resistance emergence. Data on WBS for population-level AMR in the Arabian-Gulf remain limited. This study assessed Staphylococcus diversity and resistance in Dubai wastewater. Samples were collected over eight months from nine community sites, two hospital nodes, and two wastewater treatment plants (WWTPs) and were analysed by culture-based method. Ninety-six Staphylococcus isolates were recovered from community, hospital, and WWTP influent, with no growth in effluent. Most isolates (n/N = 88/96) were coagulase-negative Staphylococcus (CoNS), spanning 15 species, dominated by S. saprophyticus, S. cohnii and S. sciuri. The only coagulase-positive Staphylococcus was S. aureus (n = 8) and the only species detected across all wastewater sources. Resistance was highest to benzylpenicillin (88%) and fusidic acid (82%), whereas all isolates remained susceptible to glycopeptides, tigecycline, and linezolid. Fusidic acid resistance was higher in community-wastewater isolates, whereas β-lactam resistance predominated in hospital-wastewater isolates. Sixty percent of CoNS were multidrug-resistant; methicillin resistance occurred in 37.5% of CoNS and 50% of S. aureus. Wastewater is a reservoir of diverse multidrug-resistant staphylococci, underscoring One Health relevance reflecting the potential for circulation between humans, animals, and the shared environment. WBS can support population-level AMR monitoring to inform public health and veterinary interventions. Full article

Objectives: Infective endocarditis (IE) is a feared and life-threatening complication, requiring a multidisciplinary approach. Prosthetic valve endocarditis (PVE) accounts for 20–30% of IE, is one of the most severe forms of IE, and is associated with high morbidity and mortality. We aim to compare and analyze baseline characteristics, microbiology, clinical presentation, complications, and prognosis between biological and mechanical PVE; we also carried out a subgroup analysis of patients aged 45–65 at the time of onset of prosthetic surgery. Methods: The present study is a post hoc analysis of a prospective multicenter cohort of patients with PVE between January 2008 and December 2023. Patients were divided into two groups regarding the type of prosthesis, mechanical vs. biological. Results: A total of 1544 patients were included. 733 (47.47%) patients with mechanical PVE (mPVE) and 811 (52.52) with biological PVE (bPVE). We found that bPVE appeared earlier than mPVE, had more healthcare-related infections and paravalvular complications. Both groups had similar clinical presentations; moreover, there was no difference in surgical indication and if surgery was performed. On the other hand, mPVE has a higher incidence of Staphylococcus aureus (SA) and Gram-negative bacteria, while bPVE has more coagulase-negative staphylococci. Multivariable logistic regression identified the following independent risk factors of mortality: EuroSCORE I, age, mPVE, SA, IE comprising two valves, and severe sepsis. mPVE had a higher mortality on admission, probably due to a higher incidence of septic shock and CNS embolism. The subgroup analysis of patients between 45 and 65 years at the time of prosthesis implantation showed similar results. Conclusions: The present analysis shows that bPVE appears earlier than mPVE, even in the subgroup of patients aged 45–65. bPVE has more healthcare-related infections and more paravalvular complications. After adjusting for baseline differences, mPVE had higher in-hospital mortality. Full article

Linezolid (LZD) is an oxazolidinone antibiotic effective in the treatment of infection with Gram-positive bacteria, including methicillin-resistant Staphylococcus aureus (MRSA). The decline in susceptibility to linezolid is a concern for antimicrobial chemotherapy. In this study, the prevalence of the LZD minimum inhibitory concentration (MIC) of 2 mg/L (LZD-MIC2), which represents a slightly high value within a range of susceptibility for S. aureus (≤4 mg/L), was investigated retrospectively for staphylococcal species from different sources. We collected the records of LZD MIC of Staphylococcus/Mammaliicoccus that had been obtained in our previous studies on isolates from patients, healthy individuals, and foodstuff. Prevalence of isolates showing LZD-MIC2 was analyzed depending on the type of staphylococcal species and S. aureus clones. In clinical isolates, methicillin-susceptible S. aureus (MSSA) and S. argenteus showed significantly higher LZD-MIC2 rates (20.0% and 21.5%, respectively) than MRSA (7.3%). Among clinical and colonizing isolates of MSSA, LZD-MIC2 was more commonly found in CC1 (ST188, ST2990, etc.), CC8, CC15, ST30, ST97, and ST121 than other lineages. In S. argenteus isolates, which were mostly methicillin-susceptible, there was no significant difference in the LZD-MIC2 prevalence among the three genotypes. The LZD-MIC2 was detected in 18.3% of coagulase-negative staphylococci (CoNS), with S. saprophyticus, S. pasteuri, and M. sciuri showing higher prevalence (30–57%) than other species. The present study revealed that the prevalence of the LZD-MIC2 is different depending on staphylococcal species/types, as they are more common in specific MSSA lineages and some CoNS species. Full article

Standard therapy for infective endocarditis (IE) usually requires 4–6 weeks of intravenous (IV) antibiotics, ensuring sustained bactericidal concentrations, yet resulting in prolonged hospitalization and increased cost of care. These challenges have driven interest in oral antibiotic therapy (OAT) as a step-down strategy for selected, clinically stable patients. This review summarizes the clinical evidence and pharmacokinetic and pharmacodynamic (PK/PD) rationale and practical considerations supporting step-down OAT in IE. Antibiotics such as amoxicillin, fluoroquinolones, linezolid, and rifampicin have high bioavailability and maintain effective serum and tissue concentrations, and can be used as a safe transition from IV to oral therapy. The pivotal POET randomized controlled trial (RCT) demonstrated noninferiority of OAT compared with continued IV therapy in stable patients with left-sided IE caused by Streptococcus spp., Enterococcus faecalis, methicillin-susceptible Staphylococcus aureus, or coagulase-negative staphylococci. Further real-world studies and meta-analyses confirmed comparable efficacy and safety, with reduced catheter-related complications and shorter hospitalization length for patients receiving OAT. The latest European Society of Cardiology (ESC) guidelines have incorporated OAT regimens derived from the POET protocol for stable patients meeting specific criteria, while the American Heart Association guidelines have not yet been revised. Many areas remain uncertain, such as the optimal timing of transition to oral therapy; the ideal antibiotic combinations and dosing; and the applicability to complex cases such as methicillin-resistant S. aureus (MRSA), Gram-negative, or pediatric infections. Overall, clinical evidence supports OAT as a safe and effective alternative to prolonged IV therapy in selected patients with IE, highlighting a major step toward more individualized, patient-centered management. Full article

This study evaluated the microbiological quality, presence of virulence genes, and antimicrobial resistance of Staphylococcus aureus and Escherichia coli in sheep and goat milk and traditional Romanian dairy products (Telemea and Burduf cheeses). Raw milk contained high levels of coagulase-positive staphylococci (CPS; 5.2 log CFU/mL) and E. coli (4.3 log CFU/mL), with several samples exceeding legal limits. Sour cream exhibited moderate CPS (1.2–1.9 log CFU/g) and E. coli (0.4–3.12 log CFU/g) counts, with occasional non-compliance. Cheeses had low CPS (0.52–0.84 log CFU/g) and E. coli (0.37–0.89 log CFU/g) levels, all within permissible limits. Molecular analysis detected the nuc gene in 21 sheep milk samples, of which 85.7% also carried the sea gene and 14.3% carried seb. Additionally, two goat milk samples tested positive for both nuc and sea. Three Telemea cheese samples were also sea-positive. Among raw milk samples, 10 E. coli isolates carried stx1, and two additionally harbored hly, while dairy products were negative for E. coli virulence genes. Antimicrobial susceptibility testing showed high resistance of S. aureus to penicillin (90.5%) and ampicillin (85.7%), with multidrug resistance among sea- and seb-positive isolates. STEC isolates showed resistance to ampicillin (70%), tetracycline (50%), and trimethoprim–sulfamethoxazole (40%), but remained susceptible to amoxicillin–clavulanic acid. Full article

Staphylococcal enterotoxins (SEs), particularly enterotoxin C (SEC), are potent superantigens primarily known for causing food poisoning, but recent studies have highlighted their potential role in immune-mediated intestinal diseases. Despite the widespread use of food preservatives, their influence on SEC production—especially from coagulase-negative staphylococci (CNS)—remains poorly understood. In this study, we evaluated the effects of commonly used preservatives, including sodium chloride, potassium nitrate, and sorbic acid, on the expression and production of SEC₃ and SEC_epi in Staphylococcus aureus and S. epidermidis, respectively. Using ELISA and RT-qPCR, we analyzed toxin levels at both the protein and mRNA levels. Proliferation assays on human PBMCs assessed the mitogenic potential of culture supernatants. While sodium chloride and potassium nitrate did not significantly alter SEC levels or bacterial growth, only sorbic acid at 0.07% consistently inhibited both mRNA expression and protein production of SEC₃ and SEC_epi. Furthermore, supernatants from sorbic acid-treated cultures induced significantly lower PBMC proliferation. These results suggest that even sub-emetic concentrations of enterotoxins may have immunomodulatory effects, and sorbic acid could be a promising agent in mitigating such risks. Full article

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. Full article

Osteoarticular infections (OAIs), including osteomyelitis, septic arthritis, prosthetic joint infections, and facture-related infections, remain a major challenge due to biofilm formation and the prevalence of multidrug-resistant (MDR) pathogens. Although OAIs are predominantly caused by Staphylococcus aureus and coagulase-negative staphylococci, the increasing incidence of MDR Gram-negative infections adds further complexity to their management. Standard approaches, combining surgery and prolonged antibiotic therapy, frequently result in recurrence and poor outcomes. Bacteriophage (phage) therapy has emerged as a promising adjunct or alternative approach, offering high host specificity, replication at the infection site, and activity against biofilm-embedded bacteria. This review highlights recent advances in phage therapy for OAIs, focusing on administration routes (intravenous, intra-articular, topical, and oral) and on novel pharmaceutical delivery systems such as hydrogels, bone cements, microparticles, nanoparticles, and implant coatings. Preclinical and early clinical studies have analyzed phage stability, controlled release, and the synergistic effects of combined phage/antibiotic therapy. However, challenges remain regarding standardization, immunogenicity, and regulatory approval. Nonetheless, phage therapy shows promise for clinical translation as an adjunct or alternative to conventional treatments for OAIs. Well-designed clinical trials are urgently needed to confirm the efficacy of phage therapy, optimize delivery strategies, and integrate the treatments in routine practice. Despite encouraging outcomes for a successful clinical implementation, regulation and standardization of GMP production are required. Full article

Antimicrobial resistance (AMR) is a growing global health concern with profound implications for ophthalmology, where it compromises the management of ocular infections such as bacterial keratitis, conjunctivitis, endophthalmitis, and postoperative complications. Resistance in common ocular pathogens, including Staphylococcus aureus (S. aureus), Streptococcus pneumoniae (S. pneumoniae), Pseudomonas aeruginosa (P. aeruginosa), and coagulase-negative staphylococci (CoNS) emerge through genetic mutations, horizontal gene transfer, and biochemical mechanisms such as enzymatic degradation, target modification, efflux pumps, and reduced membrane permeability. Biofilm formation further complicates eradication on the ocular surface and interior. The key drivers of resistance include inappropriate or prolonged topical antibiotic use, routine prophylaxis in ocular surgery, subtherapeutic dosing, and cross-resistance with systemic antimicrobials. The rise in multidrug-resistant strains, particularly methicillin-resistant S. aureus, fluoroquinolone-resistant P. aeruginosa, and drug-resistant S. pneumoniae has been linked to delayed treatment response, increased healthcare costs, and sight-threatening outcomes. Recent advances in rapid diagnostics, molecular assays, and point-of-care testing support earlier and more precise detection of resistance, enabling timely therapeutic decisions. Promising strategies to address AMR in ophthalmology include antimicrobial stewardship, novel drug delivery platforms, and alternative approaches such as bacteriophage therapy and antimicrobial peptides. Emerging tools, including genomic surveillance, artificial intelligence (AI)-driven resistance prediction, and personalized antimicrobial regimens, further expand opportunities for innovation. Collectively, this review synthesizes current evidence on AMR in ocular disease, summarizing patterns of resistance, underlying mechanisms, and clinical consequences, while highlighting strategies for mitigation and underscoring the need for global awareness and collaboration among clinicians, researchers, and policymakers to safeguard vision. Full article

Subclinical mastitis (SCM) is one of the most common and detrimental diseases affecting dairy cows, causing lower milk yield and quality. Identification of pathogenic bacteria of subclinical mastitis (PSM) in dairy cows is crucial for selecting suitable antibiotic treatments and implementing effective prophylactic measures. This paper highlights the first systematic study to investigate the PSM in buffalo farms in Guangxi, China. It also analyzes the antibiotic resistance and virulence characteristics of typical PSM. The bacteriological characteristics of 132 milk samples collected from buffaloes with SCM across 3 representative buffalo farms in Guangxi, China were investigated. A total of 1659 bacterial strains were isolated and classified into 46 genera and 183 species, where 1058 bacterial strains were identified as PSM, representing 64% of the total isolates. The frequently isolated PSM in total samples were coagulase-negative Staphylococci (55.30%), Enterococcus faecalis (51.52%), Escherichia coli (31.82%), and Klebsiella pneumoniae (28.03%). All PSM strains showed multiple antibiotic resistance. Notably, E. faecalis and Lactococcus garvieae were resistant to all 12 antibiotics, whereas Staphylococcus chromogenes (95.24%), E. coli (89.19%), K. pneumoniae (83.87%), and Staphylococcus epidermidis (83.33%) were sensitive to levofloxacin (LEV). Additionally, E. coli exhibited the strongest mortality of Galleria mellonella. This study concluded that multiple PSM are present in the milk of buffaloes suffering from SCM in Guangxi, China. LEV may be a suitable antibiotic for the treatment of PSM. In the future, it is necessary to monitor the prevalence of PSM in buffalo farms and develop control strategies to prevent their spread. Full article

This study represents the first investigation into the prevalence of pathogenic bacteria in isolated, free-ranging Eastern Grey Kangaroos (Macropus giganteus) inhabiting a human-shared environment. Samples were collected from the nasal and rectal passages of state-authorised culls of M. giganteus within a military training area, where recruits had reported recurrent cases of skin and soft tissue infections. The objective was to identify clinically relevant pathogenic microorganisms present in the nasal and rectal flora of these kangaroos. Analysis revealed carriage rates of 11% for methicillin-sensitive Staphylococcus aureus (MSSA) and 2% for methicillin-resistant S. aureus (MRSA). Other potentially pathogenic bacteria isolated included Pseudomonas spp., Streptococcus (Groups B and D), Acinetobacter spp., and multiple coagulase-negative Staphylococcus (CoNS) species. Notably, CoNS species were present in 17% of nasal isolates, with Mammaliicoccus sciuri (formerly Staphylococcus sciuri) detected in 41% of these isolates, suggesting a potential reservoir for antibiotic resistance genes and virulence factors. These findings support a One Health perspective, highlighting the interconnectedness of pathogenic bacteria, M. giganteus, humans, and their shared environment. Full article

Background and Objectives: Odontogenic infections are common emergencies in oral and maxillofacial surgery. They are typically polymicrobial, with aerobes guiding initial empirical therapy. However, regional data on their microbiology and resistance patterns in Romania are limited. This study aimed to characterize the aerobic microbial profile of odontogenic infections in Southwestern Romania and assess the antimicrobial susceptibility of isolated pathogens. Materials and Methods: A prospective observational study was conducted over 12 months at a tertiary referral hospital. Pus samples collected intraoperatively were cultured aerobically. Bacterial identification used biochemical methods and the VITEK 2 system. Antimicrobial susceptibility was determined by disk diffusion and automated MIC testing, interpreted according to EUCAST v13.0 (2023). Results: Of 110 patients, 96 (87.3%) yielded positive aerobic cultures, producing 97 isolates. Streptococcus spp. were predominant (49.5%), followed by coagulase-negative staphylococci (24.7%), Staphylococcus aureus (14.4%), Enterobacterales (7.2%), and Pseudomonas aeruginosa (3.1%). Streptococcus spp. remained susceptible to penicillin G (82.3%), amoxicillin–clavulanate (76.4%), and clindamycin (70.5%), but only 55.0% to erythromycin. Most S. aureus isolates were methicillin-susceptible (92.9%), while coagulase-negative staphylococci showed high methicillin resistance (59.3%) yet full susceptibility to linezolid, vancomycin, and teicoplanin. Enterobacterales were resistant to ampicillin (90%) and amoxicillin–clavulanate (65%) but remained susceptible to ceftriaxone (80%) and ciprofloxacin (85%). P. aeruginosa isolates were fully susceptible to piperacillin–tazobactam, ceftazidime, cefepime, and meropenem. Conclusions: This study provides regional data on aerobic pathogens in odontogenic infections. High resistance to penicillin and macrolides limits empirical use. Amoxicillin–clavulanate and clindamycin retain moderate activity, while glycopeptides, linezolid, and carbapenems preserved full efficacy. Surgical drainage remains central to management, and antibiotic therapy should be guided by local susceptibility patterns. These data provide baseline information to inform empirical therapy and stewardship efforts and highlight the need for multicenter studies including anaerobic and molecular analyses. Full article

Staphylococcus spp. present a dual role in cheese production as some species are pathogenic, while others bring beneficial characteristics. Coagulase-positive staphylococci (CoPS), particularly Staphylococcus aureus, are of concern due to their ability to produce enterotoxins linked to foodborne outbreaks. These toxins, encoded by staphylococcal enterotoxin (SE) genes, cause gastroenteritis, especially vomiting. Many members of the genus harbor a plethora of virulence genes and are able to form biofilms. The prevalence of antibiotic-resistant strains, including methicillin-resistant S. aureus (MRSA), complicates control. In contrast, some members of the coagulase-negative staphylococci (CoNS) group, such as Staphylococcus carnosus, Staphylococcus condimenti, Staphylococcus equorum, Staphylococcus piscifermentans, Staphylococcus succinus, and Staphylococcus xylosus, contribute to ripening, influencing flavor and texture. Some are even considered safe and studied for their ability to inhibit pathogens. Expression of enterotoxin genes in Staphylococcus, particularly S. aureus, is influenced by environmental factors and can be regulated by different mechanisms including quorum sensing. Understanding gene expression in conditions found during cheese production and ripening can help in formulating effective interventions. Risks posed by enterotoxin-producing Staphylococcus in cheese are evident, with numerous outbreaks reported worldwide. Moreover, several species present risks to both animal and human health. Effective control measures include adherence to microbiological criteria in foods, animal health monitoring, good manufacturing practices (GMP), temperature control, proper ripening conditions and hygiene. This review compiles and discusses existing knowledge on CoPS and CoNS in cheeses, providing a framework for evaluating their risks and benefits and guiding future studies in cheese microbiology. Full article