Integrating multi-wet laboratory diagnostics to study staphylococci in animals in Uganda.

BACKGROUND: Several diagnostic environments in Uganda lack real-time, robust and high-throughput technologies for comprehensive typing of microbes, which is a setback to infectious disease surveillance. This study combined various wet laboratory diagnostics to understand the epidemiology of pathogenic staphylococci isolated from animals in Uganda and the implications for global health security priorities. METHODS: A retrospective study was conducted employing records and pathogenic staphylococci (from animals) archived at the Central Diagnostic Laboratory (CDL), Makerere University, Uganda, between January 2012 and December 2019. The bacteria were speciated by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and tested for virulence factors [beta lactamases, lecithinase, deoxyribonuclease (DNase), haemolysins] and resistance to ten antimicrobials of clinical and veterinary relevance. Tetracycline and methicillin resistance genes were also tested. RESULTS: The prevalent diseases were mastitis in cattle and skin infections in dogs. Of the 111 staphylococci tested by MALDI-TOF MS, 79 (71.2%) were Staphylococcus aureus, 27 (24.3%) were Staphylococcus pseudintermedius and 5 (4.5%) were Staphylococcus schleiferi. All these strains expressed haemolysins. The prevalence of strains with lecithinase, penicillinase, cephalosporinase and DNase was 35.9% (14/39), 89.7% (35/39), 0.0% (0/39) and 87.2% (34/39), respectively. Staphylococci were primarily resistant to early penicillins (over 80%), tetracycline (57.7%), and chloramphenicol (46.2%). Minimal resistance was noted with cloxacillin (0.0%), ciprofloxacin (9.6%), and cefoxitin (3.8%). The prevalence of multidrug resistance (MDR) was 78.8% for general staphylococci, 82.2% for S. aureus, 73.1% for S. pseudintermedius, and 60.0% for S. schleiferi. Multidrug resistant staphylococci were significantly more prevalent in the cattle isolates than in the dog isolates (P < 0.05). The prevalence of methicillin-resistant staphylococci (MRS) tested by resistance to cefoxitin and mecA carriage was 3.8%. These four strains were all isolated from dog skin infections. The tetK gene was the most predominant (35.4%), followed by tetM (25.0%). CONCLUSION: In resource-constrained settings, the approach of integrated diagnostics promises sustainable disease surveillance and the addressing of current capacity gaps. The emergence of MRS (zoonotic bacteria) in companion animals creates a likelihood of reduced treatment options for related human infections, a threat to global health.

Prevalence and antimicrobial resistance trends among vaginal bacteria isolates from pregnant bitches.

Many of the reproductive tract infections in the bitches are caused by bacteria that can normally be present on the vaginal mucosa. These bacteria also might have an important role as the cause responsible for pregnancy loss and fetal deaths. The choice of antibiotic therapy for the pregnant animal is narrow and represents a severe problem in veterinary practice, especially due to increased antimicrobial resistance. Due to incorrect antimicrobials use in breeding kennels, the aim of the present study was to assess the occurrence of the bacterial flora isolated from the pregnant bitches and their antibiotic sensitivity. The study was carried out at the private Veterinary clinic in Novi Sad, Serbia. The vaginal swabs were taken from 60 bitches diagnosed with pregnancy and were sent to be laboratory tested. Based on the results, the most common isolated pathogens were Staphylococcus pseudintermedius (20%) and beta-hemolytic streptococci (18.33%). Furthermore, significant resistance to antibiotics from beta-lactams group was detected. It is of particular importance that antimicrobial treatment be evidence based in order to reduce the overuse of antimicrobials due to increased concern regarding antimicrobial resistance.

The relationship between resistance evolution and carbon metabolism in Staphylococcus xylosus under ceftiofur sodium stress.

Staphylococcus xylosus has emerged as a bovine mastitis pathogen with increasing drug resistance, resulting in substantial economic impacts. This study utilized iTRAQ analysis to investigate the mechanisms driving resistance evolution in S. xylosus under ceftiofur sodium stress. Findings revealed notable variations in the expression of 143 proteins, particularly glycolysis-related proteins (TpiA, Eno, GlpD, Ldh) and peptidoglycan (PG) hydrolase Atl. Following the induction of ceftiofur sodium resistance in S. xylosus, the emergence of resistant strains displaying characteristics of small colony variants (SCVs) was observed. The transcript levels of TpiA, Eno, GlpD and Ldh were up-regulated, TCA cycle proteins (ICDH, MDH) and Atl were down-regulated, lactate content was increased, and NADH concentration was decreased in SCV compared to the wild strain. That indicates a potential role of carbon metabolism, specifically PG hydrolysis, glycolysis, and the TCA cycle, in the development of resistance to ceftiofur sodium in S. xylosus.

Structural Diversification of Pyrazinone Metabolites via Spontaneous Oxa-Michael Addition in Staphylococcus xylosus.

A family of pyrazinone metabolites (1-11) were characterized from Staphylococcus xylosus ATCC 29971. Six of them were hydroxylated or methoxylated, which were proposed to be produced by the rare noncatalytic oxa-Michael addition reaction with a water or methanol molecule. It was confirmed that isopropyl alcohol can also be the Michael donor of the reaction. 1-7 and the synthetic precursor 2a showed significant inhibition of breast cancer cell migration.

Light-activated conjugated polymer nanoparticles to defeat pathogens associated with bovine mastitis.

Bovine mastitis (BM) represents a significant challenge in the dairy industry. Limitations of conventional treatments have prompted the exploration of alternative approaches, such as photodynamic inactivation (PDI). In this study, we developed a PDI protocol to eliminate BM-associated pathogens using porphyrin-doped conjugated polymer nanoparticles (CPN). The PDI-CPN protocol was evaluated in four mastitis isolates of Staphylococcus and in a hyper-biofilm-forming reference strain. The results in planktonic cultures demonstrated that PDI-CPN exhibited a bactericidal profile upon relatively low light doses (∼9.6 J/cm2). Furthermore, following a seven-hour incubation period, no evidence of cellular reactivation was observed, indicating a highly efficient post-photodynamic inactivation effect. The successful elimination of bacterial suspensions encouraged us to test the PDI-CPN protocol on mature biofilms. Treatment using moderate light dose (∼64.8 J/cm2) reduced biofilm biomass and metabolic activity by up to 74% and 88%, respectively. The impact of PDI-CPN therapy on biofilms was investigated using scanning electron microscopy (SEM), which revealed nearly complete removal of the extracellular matrix and cocci. Moreover, ex vivo studies conducted on bovine udder skin demonstrated the efficacy of the therapy in eliminating bacteria from these scaffolds and its potential as a prophylactic method. Notably, the histological analysis of skin revealed no signs of cellular degeneration, suggesting that the protocol is safe and effective for BM treatment. Overall, this study demonstrates the potential of PDI-CPN in treating and preventing BM pathogens. It also provides insights into the effects of PDI-CPN on bacterial growth, metabolism, and survival over extended periods, aiding the development of effective control strategies and the optimization of future treatments.

Emergence of novel methicillin resistant Staphylococcus pseudintermedius lineages revealed by whole genome sequencing of isolates from companion animals and humans in Scotland.

Staphylococcus pseudintermedius is an opportunistic pathogen in dogs, and infection in humans is increasingly found, often linked to contact with dogs. We conducted a retrospective genotyping and antimicrobial susceptibility testing study of 406 S. pseudintermedius isolates cultured from animals (dogs, cats and an otter) and humans across Scotland, from 2007 to 2020. Seventy-five sequence types (STs) were identified, among the 130 isolates genotyped, with 59 seen only once. We observed the emergence of two methicillin resistant Staphylococcus pseudintermedius (MRSP) clones in Scotland: ST726, a novel locally-evolving clone, and ST551, first reported in 2015 in Poland, possibly linked to animal importation to Scotland from Central Europe. While ST71 was the most frequent S. pseudintermedius strain detected, other lineages that have been replacing ST71 in other countries, in addition to ST551, were detected. Multidrug resistance (MDR) was detected in 96.4% of MRSP and 8.4% of MSSP. A single MRSP isolate was resistant to mupirocin. Continuous surveillance for the emergence and dissemination of novel MDR MRSP in animals and humans and changes in antimicrobial susceptibility in S. pseudintermedius is warranted to minimise the threat to animal and human health.

Prevalence, genetic characteristics, and antimicrobial resistance of staphylococcal isolates from oral cavity and skin surface of healthy individuals in northern Japan.

BACKGROUND: Oral cavity is an ecological niche for colonization of staphylococci, which are a major bacterial species causing community-acquired infections in humans. In this study, prevalence, and characteristics of staphylococci in oral cavity and skin of healthy individuals were investigated in northern Japan. METHODS: Saliva from oral cavity and swab from skin surface of hand were collected and cultured on selective media. Species of the isolates were identified genetically, and ST was determined for S. aureus and S. argenteus. Genes associated with antimicrobial resistance were detected by PCR. RESULTS: Among 166 participants, a total of 75 S. aureus isolates were obtained from 61 individuals (37 %), and recovered more frequently in oral cavity (n = 48) than skin (n = 27). Among 23 STs identified in S. aureus isolates, ST8 (CC8), ST15 (CC15), and ST188 (CC1) were the most common (10 isolates each), with STs of CC1 being dominant (17 isolates). Methicillin-resistant S. aureus (MRSA) was isolated in the skin of two individuals and belonged to ST1 and ST6. Resistance to erythromycin and gentamicin associated with erm(A) and aac(6')-Ie-aph(2")-Ia, respectively, was more commonly found in ST5 and ST8 isolates. One S. argenteus isolate (ST2250, mecA-negative) was recovered from oral cavity of a participant (0.6 %). A total of 186 isolates of coagulase-negative staphylococci (CoNS) were recovered from 102 participants and identified into 14 species, with S. warneri being the most common (n = 52), followed by S. capitis (n = 42), S. saprophyticus (n = 20) and S. haemolyticus (n = 19). mecA was detected in S. saprophyticus, S. haemolyticus, and S. caprae, while arginine-catabolic mobile element (ACME) in only S. capitis and S. epidermidis. CONCLUSION: S. aureus was more prevalent in oral cavity than skin surface, belonging to three major STs, with CC1 being a dominant lineage. The prevalence of antimicrobial resistance was distinct depending on CoNS species.

Genomic analysis and identification of a novel superantigen, SargEY, in Staphylococcus argenteus isolated from atopic dermatitis lesions.

During surveillance of Staphylococcus aureus in lesions from patients with atopic dermatitis (AD), we isolated Staphylococcus argenteus, a species registered in 2011 as a new member of the genus Staphylococcus and previously considered a lineage of S. aureus. Genome sequence comparisons between S. argenteus isolates and representative S. aureus clinical isolates from various origins revealed that the S. argenteus genome from AD patients closely resembles that of S. aureus causing skin infections. We previously reported that 17%-22% of S. aureus isolated from skin infections produce staphylococcal enterotoxin Y (SEY), which predominantly induces T-cell proliferation via the T-cell receptor (TCR) Vα pathway. Complete genome sequencing of S. argenteus isolates revealed a gene encoding a protein similar to superantigen SEY, designated as SargEY, on its chromosome. Population structure analysis of S. argenteus revealed that these isolates are ST2250 lineage, which was the only lineage positive for the SEY-like gene among S. argenteus. Recombinant SargEY demonstrated immunological cross-reactivity with anti-SEY serum. SargEY could induce proliferation of human CD4+ and CD8+ T cells, as well as production of TNF-α and IFN-γ. SargEY showed emetic activity in a marmoset monkey model. SargEY and SET (a phylogenetically close but uncharacterized SE) revealed their dependency on TCR Vα in inducing human T-cell proliferation. Additionally, TCR sequencing revealed other previously undescribed Vα repertoires induced by SEH. SargEY and SEY may play roles in exacerbating the respective toxin-producing strains in AD. IMPORTANCE: Staphylococcus aureus is frequently isolated from active lesions of atopic dermatitis (AD) patients. We reported that 17%-22% of S. aureus isolated from AD patients produced a novel superantigen staphylococcal enterotoxin Y (SEY). Unlike many S. aureus superantigens that activate T cells via T-cell receptor (TCR) Vß, SEY activates T cells via TCR Vα and stimulates cytokine secretion. Staphylococcus argenteus was isolated from AD patients during the surveillance for S. aureus. Phylogenetic comparison of the genome indicated that the isolate was very similar to S. aureus causing skin infections. The isolate encoded a SEY-like protein, designated SargEY, which, like SEY, activated T cells via the TCR Vα. ST2250 is the only lineage positive for SargEY gene. ST2250 S. argenteus harboring a superantigen SargEY gene may be a novel staphylococcal clone that infects human skin and is involved in the exacerbation of AD.

Benchmarking classification abilities of novel optical photothermal IR spectroscopy at the single-cell level with bulk FTIR measurements.

Fourier-transform infrared (FTIR) spectroscopy is a simple, fast and inexpensive method with a history of use for bacterial analysis. However, due to the limitations placed on spatial resolution inherent to infrared wavelengths, analysis has generally been performed on bulk samples, leading to biological variance among individual cells to be buried in averaged spectra. This also increases the bacterial load necessary for analysis, which can be problematic in clinical settings where limiting incubation time is valuable. Optical photothermal-induced resonance (O-PTIR) spectroscopy is a novel method aiming to bypass this limitation using a secondary lower wavelength laser, allowing for infrared measurements of a single bacterium. Here, using Staphylococcus capitis, Staphylococcus epidermidis and Micrococcus luteus strains as a model and FTIR as a benchmark, we examined O-PTIR's ability to discriminate single-cell samples at the intergenetic, interspecific and intraspecific levels. When combined with chemometric analysis, we showed that O-PTIR is capable of discriminating different between genera, species and strains within species to a degree comparable with FTIR. Furthermore, small variations in the amide bands associated with differences in the protein structure can still be seen in spite of smaller sample sizes. This demonstrates the potential of O-PTIR for single-cell bacterial analysis and classification.

Comparative genome wise analysis of codon usage of Staphylococcus Genus.

The genus Staphylococcus encompasses a diverse array of bacteria with significant implications for human health, including disreputable pathogens such as Staphylococcus aureus and Staphylococcus epidermidis. Understanding the genetic composition and codon usage patterns of Staphylococcus species is crucial for unraveling their evolutionary dynamics, adaptive strategies, and pathogenic potential. In this study, we conducted a comprehensive analysis of codon usage patterns across 48 species within the Staphylococcus genus. Our findings uncovered variations in genomic G-C content across Staphylococcus species, impacting codon usage preferences, with a notable preference for A/T-rich codons observed in pathogenic strains. This preference for A/T-rich codons suggests an energy-saving strategy in pathogenic organisms. Analysis of dinucleotide pair expression patterns unveiled insights into genomic dynamics, with overrepresented codon pairs reflecting trends in dinucleotide expression across genomes. Additionally, a significant correlation between CAI and genomic G-C content underscored the intricate relationship between codon usage patterns and gene expression strategies. Amino acid usage analysis highlighted preferences for energetically cheaper amino acids, suggesting adaptive strategies promoting energy efficiency. This comprehensive analysis sheds light on the evolutionary dynamics and adaptive mechanisms employed by Staphylococcus species, providing valuable insights into their pathogenic potential and clinical implications. Understanding these genomic features is crucial for devising strategies to combat staphylococcal infections and improve public health outcomes.

Identification and antimicrobial susceptibility profiles of Staphylococcus species isolated from raw cow milk, and swabs in smallholder dairy farms in Meta district, Eastern Ethiopia.

BACKGROUND: The safety of milk production in terms of foodborne infections is a worldwide issue, particularly in developing countries where production is often unhygienic. A cross-sectional study was conducted from December 2018 to August 2019 in the Meta District of Eastern Hararghe Zone, Oromia Regional State, Ethiopia. We aim to assess milk hygiene practices among smallholder dairy farmers, estimate the prevalence of Staphylococcus aureus in raw cow milk and swabs, assess associated risk factors, and the antimicrobial susceptibility test of S. aureus isolates. Face-to-face interviews with 30 respondents randomly selected from smallholder dairy farmers were used to assess the potential risk factors for S. aureus contaminations in milk. A total of 177 samples were examined using standard microbiological testing. The disc diffusion technique was also employed to assess the antibiotic susceptibility of the isolates. The data was analyzed using STATA® version 14.0 statistical software. RESULTS: According to the milk hygiene assessment, 80% of respondents did not wash cow udder before milking, did not use detergent to clean milk containers, and did not keep milk refrigerated before consumption or sale, while 63.3% of milk consumers ingested raw milk. They had never heard of staphylococci foodborne disease. Likewise, the overall prevalence of S. aureus was 12.42% (95%CI: 8.32-18.98). The prevalence of S. aureus in udder milk, equipment swabs, and milkers' hands was 18.8%, 26.7%, and 30%, respectively. The prevalence of S. aureus in milk is significantly associated with age, and mastitis history (p < 0.05). Moreover, old and mastitis positive animals were eight (OR: 8.40; 95%CI: 1.68-41.89) and four (OR: 4.33; 95%CI: 1.37-13.66) times more likely to be infected by S. aureus than adult, and mastitis negative animal. The isolates were resistant to penicillin G (97.4%) and tetracycline (69.2%) whereas susceptible to kanamycin, streptomycin, vancomycin, and cefotaxime, at 84.6%, 71.8%, 64%, and 58.8%, respectively. CONCLUSION: This study revealed the presence of antimicrobial-resistant patterns of S. aureus on commonly used antibiotics, as well as inadequate milk handling practices in the study area. Thus, awareness should be created on proper milk handling and hygiene as well as appropriate uses of antibiotics should be encouraged.

Coagulase-negative staphylococci from bovine milk: Antibiogram profiles and virulent gene detection.

BACKGROUND: Coagulase-negative Staphylococcus species are an emerging cause of intramammary infection, posing a significant economic and public health threat. The aim of this study was to assess the occurrence of coagulase-negative Staphylococcus species in bovine milk and dairy farms in Northwestern Ethiopia and to provide information about their antibiotic susceptibility and virulence gene profiles. METHODS: The cross-sectional study was conducted from February to August 2022. Coagulase-negative Staphylococcus species were isolated from 290 milk samples. Species isolation and identification were performed by plate culturing and biochemical tests and the antimicrobial susceptibility pattern of each isolate was determined by the Kirby-Bauer disc diffusion test. The single-plex PCR was used to detect the presence of virulent genes. The STATA software version 16 was used for data analysis. The prevalence, proportion of antimicrobial resistance and the number of virulent genes detected from coagulase-negative Staphylococcus species were analyzed using descriptive statistics. RESULTS: Coagulase-negative Staphylococcus species were isolated in 28.6%, (95% CI: 23.5-34.2) of the samples. Of these, the S. epidermidis, S. sciuri, S. warneri, S. haemolyticus, S. simulans, S. chromogens, S. cohnii, and S. captis species were isolated at the rates of 11, 5.2, 3.4, 3.1, 3.1, 1, 1, and 0.7% respectively. All the isolates showed a high percentage (100%) of resistance to Amoxicillin, Ampicillin, and Cefotetan and 37.5% of resistance to Oxacillin. The majority (54.2%) of coagulase-negative isolates also showed multidrug resistance. Coagulase-negative Staphylococcus species carried the icaD, pvl, mecA, hlb, sec, and hla virulent genes at the rates of 26.5%, 22.1%, 21.7%, 9.6%, 9.6% and 8.4% respectively. CONCLUSION: The present study revealed that the majority of the isolates (54.2%) were found multidrug-resistant and carriage of one or more virulent and enterotoxin genes responsible for intramammary and food poisoning infections. Thus, urgent disease control and prevention measures are warranted to reduce the deleterious impact of coagulase-negative species. To the best of our knowledge, this is the first study in Ethiopia to detect coagulase-negative Staphylococcus species with their associated virulent and food poisoning genes from bovine milk.

Chromosomal and plasmid localization of ileS2 in high-level mupirocin-resistant Staphylococcus pseudintermedius and Staphylococcus aureus isolated from canine and feline origins.

OBJECTIVES: To characterize the mobile genetic elements and genetic localization of ileS2 in high-level mupirocin-resistant (Hi-MupR) methicillin-resistant Staphylococcus pseudintermedius (MRSP) and MRSA isolates recovered from canine and feline clinical samples. METHODS: The identification of bacterial species and presence of mecA and ileS2 genes in MRSP and MRSA isolates were performed using MALDI-TOF MS and PCR, respectively. Antimicrobial resistance (AMR) phenotypes were determined by broth microdilution assays. The genome characteristics, ileS2-containing elements and staphylococcal cassette chromosome mec (SCCmec) were illustrated using complete circular genomes obtained from hybrid assembly of Illumina short-reads and Oxford Nanopore Technologies long-reads. These were analysed through phylogenetic and bioinformatics approaches. RESULTS: A total of 18 MRSP clinical isolates and four MRSA clinical isolates exhibited the Hi-MupR phenotype and carried multiple AMR genes, including mecA and ileS2 genes. MRSP ST182-SCCmec V (n = 6) and ST282-ΨSCCmec57395-t10 (n = 4) contained the ileS2 transposable unit associated with IS257 on the chromosome. Three MRSA ST398-SCCmec V-t034/t4652 isolates carried ∼42 kb pSK41-like ileS2 plasmids, whereas similar ileS2 plasmids lacking tra genes were found in MRSP ST282-ΨSCCmec57395-t72/t21 isolates. Furthermore, a new group of ileS2 plasmids, carried by MRSP ST45-ΨSCCmec57395, ST433-ΨSCCmecKW21-t05 and ST2165-SCCmec IV-t06, and by one MRSA ST398-SCCmec V-t034 strain, shared the plasmid backbone with the cfr/fexA-carrying plasmid pM084526_1 in MRSA ST398. CONCLUSIONS: This study provides the first evidence of ileS2 integration into the S. pseudintermedius chromosome, which is a rare occurrence in staphylococcal species, and plasmids played a pivotal role in dissemination of ileS2 in both staphylococcal species.

Enhancement of colour formation of fermented sausages by overexpression of nitric oxide synthase in Staphylococcus vitulinus under hydrogen peroxide stress.

This study used hydrogen peroxide (H2O2) treatment to overexpress the gene of nitric oxide synthase (nos) in Staphylococcus vitulinus, which was then inoculated into fermented sausages to observe its effect on colour development. The results showed that a low concentration of H2O2 (50 mM) could up-regulate the expression of nos by increasing the oxidative stress level of S. vitulinus. At 2 h after treatment, the expression of nos in S. vitulinus was the highest (P < 0.05), and the relative enzyme activity was increased to about 1.5 times that of the untreated. The growth of S. vitulinus was not substantially affected by 50-mM H2O2 treatment (P > 0.05). When H2O2-treated S. vitulinus was inoculated into fermented sausages, the content of nitrosomyoglobin was increased, and the a*-value (indicating redness) was not significantly different from that in the group treated with nitrite (P > 0.05). This study provides a potential method to enhance the ability of S. vitulinus for colourising fermented sausage by inducing the overexpression of nos.

Short communication: Goat mastitis and the formation of neutrophil extracellular traps (NETs).

Mastitis, an inflammation of the mammary gland affecting milk production and quality in dairy herds, is often associated with Staphylococcus spp. in goats. Neutrophils are crucial in combating infections by migrating into milk and deploying various defense strategies, including the release of neutrophil extracellular traps (NETs) composed of DNA, histones, and bactericidal proteins. This study investigated whether NETs are released by goat neutrophils stimulated in vitro by Staphylococcus aureus and Staphylococcus warneri, two common pathogens of goat mastitis. PMNs were isolated from blood from healthy adult goats. We evaluated goat NET formation by stimulating cells with: phorbol 12-myristate 13-acetate (PMA) as a positive control, cytochalasin for inhibition of actin polymerization, S. aureus, and S. warneri. NET formation was observed in response to chemical stimulation and bacterial presence, effectively trapping pathogens. Variations in NET formation between S. aureus and S. warneri suggest pathogen-specific responses. These findings suggest that the formation of NETs may be an important complementary mechanism in the defense against mastitis in goats. In conclusion, this study unveils a novel defense mechanism in goats, indicating the role of NETs against S. aureus and S. warneri in mastitis.

Exploring therapeutic options for mild diabetic-related foot infections: a comparative in vitro study of cefditoren versus amoxicillin/clavulanic acid.

Skin and soft tissue infections (SSTIs), and particularly diabetic-related foot infections (DFI), present diagnostic and therapeutic complexities, often leading to severe complications. This study aims to evaluate the in vitro efficacy of cefditoren and amoxicillin/clavulanic acid against typical DFI pathogens. Clinical samples from 40 patients with mild SSTIs were analyzed, revealing a predominance of Staphylococcus spp. and Streptococcus spp. species. Cefditoren exhibited activity against 90% of isolates, with superior potency over amoxicillin/clavulanic acid. These findings underscore the utility of cefditoren in empirical treatment of DFI, although a larger sample size would be desirable for further validation.

The nasal microbiota is a potential diagnostic biomarker for sepsis in critical care units.

This study aimed to characterize the composition of intestinal and nasal microbiota in septic patients and identify potential microbial biomarkers for diagnosis. A total of 157 subjects, including 89 with sepsis, were enrolled from the affiliated hospital. Nasal swabs and fecal specimens were collected from septic and non-septic patients in the intensive care unit (ICU) and Department of Respiratory and Critical Care Medicine. DNA was extracted, and the V4 region of the 16S rRNA gene was amplified and sequenced using Illumina technology. Bioinformatics analysis, statistical processing, and machine learning techniques were employed to differentiate between septic and non-septic patients. The nasal microbiota of septic patients exhibited significantly lower community richness (P = 0.002) and distinct compositions (P = 0.001) compared to non-septic patients. Corynebacterium, Staphylococcus, Acinetobacter, and Pseudomonas were identified as enriched genera in the nasal microbiota of septic patients. The constructed machine learning model achieved an area under the curve (AUC) of 89.08, indicating its efficacy in differentiating septic and non-septic patients. Importantly, model validation demonstrated the effectiveness of the nasal microecological diagnosis prediction model with an AUC of 84.79, while the gut microecological diagnosis prediction model had poor predictive performance (AUC = 49.24). The nasal microbiota of ICU patients effectively distinguishes sepsis from non-septic cases and outperforms the gut microbiota. These findings have implications for the development of diagnostic strategies and advancements in critical care medicine.IMPORTANCEThe important clinical significance of this study is that it compared the intestinal and nasal microbiota of sepsis with non-sepsis patients and determined that the nasal microbiota is more effective than the intestinal microbiota in distinguishing patients with sepsis from those without sepsis, based on the difference in the lines of nasal specimens collected.

An update on non-aureus staphylococci and mammaliicocci in cow milk: unveiling the presence of Staphylococcus borealis and Staphylococcus rostri by MALDI-TOF MS.

Non-aureus staphylococci and mammaliicocci (NASM) are the microorganisms most frequently isolated from milk. Given their numerosity and complexity, MALDI-TOF MS is one of the preferred species identification approaches. Nevertheless, reference mass spectra for the novel species Staphylococcus borealis were included only recently in the Bruker Biotyper System (MBT) library, and other species of veterinary interest such as S. rostri are still absent. This work provides an updated picture of the NASM species found in milk, gained by retrospectively analyzing the data relating to 21,864 milk samples, of which 6,278 from clinical mastitis (CM), 4,039 from subclinical mastitis (SCM), and 11,547 from herd survey (HS), with a spectrum library including both species. As a result, S. borealis was the second most frequently isolated NASM (17.07%) after S. chromogenes (39.38%) in all sample types, with a slightly higher percentage in CM (21.84%), followed by SCM (17.65%), and HS (14.38%). S. rostri was also present in all sample types (3.34%), reaching 8.43% of all NASM in SCM and showing a significant association (p < 0.01) with this condition. Based on our findings, the presence of S. borealis and S. rostri in milk and their potential association with mastitis might have been overlooked, possibly due to the difficulties in differentiating these species from other closely related NASM. Our results indicate that S. borealis could be a more frequent contributor to bovine udder infections than previously thought and that S. rostri should also not be underestimated considering its significant association with SCM.