Microbiota of Chronic Suppurative Otitis Media and its Radiological Correlation in Severity of Disease.

Objective: The objective of the study was to find out the microbiota of cases of chronic suppurative otitis media and its radiological correlation in disease severity. Methodology: 50 patients with CSOM were prospectively studied. Swabs were taken and cultured for bacteria. HRCT temporal bone was done and microbiota relation with severity was studied. Result: We found the predominant organism to be staphylococcus aureus (44%) followed by psedumonas (22%). On radiological correlation maximum erosive property was seen with pseudomonas followed by methicillin sensitive staphylococcus aureus and Coagulase negative staphylococcus aureus.

Udder health, bacterial isolation and antimicrobial sensitivity of Staphylococcus species from non-dairy goats on smallholder farms in Hong Kong.

This research article describes an investigation into the udder health, bacterial isolation and antimicrobial sensitivity of three staphylococcal species isolated from the milk of non-dairy goats, suckling their kids, on two smallholder farms in the Hong Kong Special Administrative Region. Udder lesions were visually noted in 21 of 34 goats and two goats had palpable abnormalities. Collected milk samples grew a total of 11 bacterial organisms and the most frequently isolated organism was Staphylococcus chromogenes. Selected isolates of S. aureus, caprae and simulans from both farms were tested by antimicrobial sensitivity testing for 23 antimicrobials and all isolates showed antimicrobial resistance to doxycycline and tetracycline. Less common resistance was shown to ampicillin, chloramphenicol, penicillin and rifampicin. This preliminary study confirms the presence of udder lesions and mastitis bacteria in non-dairy goats in Hong Kong, along with the first information on the antimicrobial profile of three common Staphylococcus species bacteria affecting goats.

Staphylococcus simulans infections in a patient following high supracondylar osteotomy to treat osteoarthritis: a case report.

Staphylococcus simulans (S. simulans) is a coagulase-negative staphylococcus that is commonly found in animal pathogens. S. simulans rarely causes infections in clinical practice due to its low pathogenic ability and opportunistic pathogen, which results in few relevant clinical reports. In this paper, the authors primarily report a patient infected with S. simulans after a high supracondylar osteotomy and the S. simulans was identified by the means of the next-generation sequencing technology. This case report provides new evidence for the further research of S. simulans and paves the way for its clinical therapy.

Virulence, Susceptibility Profile, and Clinical Characteristics of Pathogenic Coagulase-Negative Staphylococci.

Background Coagulase-negative staphylococci (CoNS) are emerging as clinically significant pathogens. A high proportion of methicillin resistance along with intense biofilm-producing ability render CoNS-related infections challenging to treat. This study was undertaken to investigate the mechanisms of methicillin resistance, identify genes encoding for virulence, and their association with clinical outcomes among clinical isolates of Staphylococci in a tertiary care center. Methods A total of 203 clinical isolates were included in this study. Susceptibility to various antibiotics was determined by the disc diffusion method. Methicillin resistance was screened using cefoxitin disc, mecA and mecC genes were detected using polymerase chain reaction (PCR). PCR was performed to detect five virulence genes: atlE, aap, fbe, embp, and icaAB. Staphylococcal cassette chromosome mec (SCCmec) types were identified by multiplex PCR. Statistical analysis was performed using SPSS software (IBM Inc., Armonk, New York). The Chi-squared test was used to compare the distribution of virulence genes among methicillin-susceptible resistant CoNS. A p-value of less than 0.5 was considered significant. Results In the current study, 60% (122/203) of CoNS were methicillin-resistant, and SCCmec type I was the most common. Among the 203 CoNS, 24.6% (50/203) isolates harbored one or more virulence genes in them.  Conclusion CoNS have relatively low virulence as only 24.6% of isolates carried the virulence genes. Nevertheless, the variety of diseases linked to these species indicates the necessity for accurate identification and precise reporting of antimicrobial susceptibility to avoid adverse outcomes.

Aetiologies of Ear Infections Among Patients Who Visited King Fahad Hospital in Al-Baha, Saudi Arabia.

Background Ear infections encompass otitis media (OM) which is a significant cause of hearing loss and otitis externa (OE) which may affect the surrounding tissues leading to serious complications. This study reports the common pathogens causing ear infections. Methods Microbiological, clinical, and demographic data of ear-infected patients who visited King Fahad Hospital in Al-Baha, Saudi Arabia, during the period from January 2019 to June 2023 were enrolled in this study. Result  This study enrolled 307 patients aged 1-94 years, with a median age of 40 years (IQR=22-57). Overall, the detectable infection rate was 81.1% (n=249), while 18.9% (n=58) had no identified aetiology. Of all isolates, 178 (58%) were bacterial, while 71 (23.1%) were fungal. Staphylococcus aureus (S. aureus) followed by Pseudomonas aeruginosa (P. aeruginosa), Enterobacteriaceae, andcoagulase-negative Staphylococcus (CoNS) were the main bacterial isolates. Of the total 63 S. aureus isolates, 21 (33%) were methicillin-resistant (MRSA). A cohort of 227 subjects were diagnosed with either OM (n=178; 79.5%), OE (n=46; 20.5%), or both OM and OE (n=3; 1%). Of those with OM, children constituted 89.1% (41/46) as compared to 75.3% (134/178) of adults (p=0.041). The main isolates from OM patients were S. aureus followed by P. aeruginosa and fungi. Of 49 OE patients, 16 (32.7%) had no identified pathogen, while 15 (30.6%) had fungi, and 13 (29.5%) had P. aeruginosa. Conclusions Ear infections in general were mainly bacterial followed by fungal with a considerable proportion of unidentified aetiology. A significant proportion of S. aureus isolates were MRSA. S. aureus followed by P. aeruginosa and fungi were the main causes of OM, while fungi followed by P. aeruginosa were the main causes of OE.

Phenotypic Variation in Staphylococcus aureus during Colonisation Involves Antibiotic-Tolerant Cell Types.

Staphylococcus aureus is a bacterial species that is commonly found colonising healthy individuals but that presents a paradoxical nature: simultaneously, it can migrate within the body and cause a range of diseases. Many of these become chronic by resisting immune responses, antimicrobial treatment, and medical intervention. In part, this ability to persist can be attributed to the adoption of multiple cell types within a single cellular population. These dynamics in the S. aureus cell population could be the result of its interplay with host cells or other co-colonising bacteria-often coagulase-negative Staphylococcal (CoNS) species. Further understanding of the unique traits of S. aureus alternative cell types, the drivers for their selection or formation during disease, as well as their presence even during non-pathological colonisation could advance the development of diagnostic tools and drugs tailored to target specific cells that are eventually responsible for chronic infections.

Sinensetin interferes with Staphylococcus aureus infections by targeting staphylocoagulase and improves infection survival rates in mouse model of pneumonia.

AIMS: Coagulase (Coa), a crucial virulence factor of Staphylococcus aureus (S. aureus), is considered a vital target for anti-virulence strategies. The research aimed to discover a natural compound capable of inhibiting S. aureus infection by targeting the virulence factor Coa. METHODS AND RESULTS: The study showed that sinensetin at a concentration of 128 µg mL-1 effectively inhibited both Coa-induced coagulation and biofilm formation in S. aureus. However, western blot results indicated that sinensetin did not impact the expression of Coa protein, suggesting that sinensetin may directly target Coa to counteract the virulence of S. aureus. Thermal shift assay results demonstrated that sinensetin enhanced the thermal stability of Coa, supporting the theory of direct binding. Molecular docking and point mutation experiments identified two key binding sites for sinensetin to Coa as R73A-Coa and R204A-Coa. In vivo studies on mice revealed that sinensetin not only reduced lung tissue damage caused by S. aureus infection, but also decreased inflammatory factors in the lung lavage fluid. Furthermore, combining sinensetin with oxacillin improved the survival rates of the Galleria mellonella and mice. CONCLUSIONS: Sinensetin is a promising natural compound that acts as a direct inhibitor of Coa against S. aureus infections.

Microbiological quality of vegan alternatives to dairy and meat products in England during 2022-3.

AIMS: Plant-based alternatives to meat and dairy products have become increasingly popular in the UK. Despite a public perception that they have a relatively low microbiological risk, outbreaks of illness have been linked with these foods. This study aimed to assess the microbiological safety and quality of vegan alternatives to dairy and meat products available in England. METHODS AND RESULTS: Samples were collected between September 2022 and March 2023 from retail, production, and catering premises, and tested for a range of bacterial pathogens and hygiene indicators using standard procedures. A total of 937 samples were tested, of which 92% were of a satisfactory microbiological quality, 3% were borderline, and 5% were unsatisfactory. Those interpreted as unsatisfactory were due to elevated counts of Enterobacteriaceae and Escherichia coli (indicators of poor hygiene) rather than pathogenic microorganisms. Listeria monocytogenes was present in five samples of tofu, all from the same producer (all at counts of <100 CFU g-1), while other Listeria species were detected at counts of <20 CFU g-1 in two burgers and two 'vegan chicken' products. The majority of samples did not have pH and water activity values that would significantly contribute to preventing microbial growth: 62.4% had pH > 5.0 and 82.4% had Aw > 0.94. CONCLUSIONS: The majority of vegan products examined were of a satisfactory quality, but results demonstrate that microbiological control must be maintained using appropriate processing and storage temperatures, and application of a safe length of shelf life.

A case of exudative pleuritis caused by Staphylococcus warneri.

This paper discusses the case of a patient with exudative bacterial pneumonia caused by Staphylococcus warneri. The patient had been abusing alcohol and nicotine for several decades, which should be considered an immunosuppressive factor. Staphylococcus warneri is part of the skin microbiome, but can also be a pathogenic agent in certain circumstances. Pleural fluid is an unusual site of isolation for the staphylococcus described. The literature contains case reports of arthritis, endocarditis, urinary tract infection or infection associated with continuous ambulatory peritoneal dialysis caused by Staphylococcus warneri. With the development of medicine, the phenomenon of immunosuppression is becoming more common, posing the threat of an increase in invasive infections caused by coagulase-negative staphylococci. In addition, an overly liberal use of antibiotics may contribute to the generation of multidrug resistance in these micro-organisms.

Evaluating the performance of the Alere PBP2a SA Culture Colony Test with the Vitek 2 Antimicrobial Susceptibility Test Card System as reference standard in coagulase-negative Staphylococcus species.

Background: The Alere PBP2a SA Culture Colony Test is an FDA-cleared in vitro immunochromatographic assay for rapid detection of penicillin-binding protein2a (PBP2a) in Staphylococcus aureus. Methods: We investigated the performance of the PBP2a SA Culture Colony Test with 78 coagulase-negative Staphylococcus (CoNS) isolates from different body sites, with the Vitek 2 Antimicrobial Susceptibility Test (AST) as a reference standard. Results: The CoNS species were 62 S. epidermidis; 6 S. lugdenensis; 3 S. hominis; 2 S. capitis; 2 S. haemolyticus; and 1 each of S. simulans, S. auricularis, and S. warneri. Of the 78 CoNS isolates, 68 showed concordance in the PBP2a IC assay and Vitek 2 AST. Discordance was seen for 10 S. epidermidis isolates, which showed negative in the PBP2a assay, despite oxacillin-resistance detection using the Vitek 2 AST (66.7% sensitivity and 100% specificity). All non-S. epidermidis CoNS were identified with 100% concordance using the PBP2a IC assay and Vitek 2 AST. Conclusion: We demonstrated that, while the PBP2a IC assay has low sensitivity in determining the susceptibility of S. epidermidis to oxacillin, it highly accurately predicted the susceptibility of non-S. epidermidis CoNS to oxacillin. The diagnostic accuracy for non-S. epidermidis CoNS needs further assessment with more isolates to confirm our findings.

Exploring staphylococcus in urinary tract infections: A systematic review and meta-analysis on the epidemiology, antibiotic resistance and biofilm formation.

This study aimed to determine the epidemiology, biofilm formation and antibiotic resistance of staphylococci collected worldwide in the context of UTIs. This systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Forty studies from 23 countries were selected for quantitative review. Electronic databases (PubMed, Scopus, Google Scholar, and Web of Sciences) were searched for articles published between 2010 and 2024 on the epidemiology, biofilm formation, and antibiotic resistance of uropathogenic staphylococci. Strict inclusion and exclusion standards were applied during the review of the articles. Forty articles were included in this systematic review. The prevalence of uropathogenic staphylococci varies from country to country, with the pooled prevalence of S. aureus and coagulase-negative staphylococci (CoNS) being 8.71 % (95 %CI: 6.145-11.69) and 13.17 % (95 %CI: 8.08-19.27) respectively. Among CoNS isolates, S. epidermidis was the most common with 19.3 % (95 %CI: 5.88-38.05). The prevalence of methicillin-resistant S. aureus isolates increased significantly from 23 % in 2010-2015 to 47 % in 2021-2024 (p = 0.03). S. haemolyticus is the most antibiotic-resistant species in CoNS, with 45 % of isolates resistant to methicillin, 33 % to gentamicin, and 29 % to tetracycline. Eighty-eight S. aureus strains were biofilm producers, including 35 % moderate biofilm producers and 48 % strong biofilm producers. The combined frequencies of icaA, clfA and fnbpA were 100, 99, and 89 %, respectively. The development of antibiotic resistance and biofilm formation by staphylococci involved in UTIs explains the need for periodic regional surveillance of these infections, which poses a serious public health problem.

Sinigrin reduces the virulence of Staphylococcus aureus by targeting coagulase.

Multi-resistant Staphylococcus aureus (S. aureus) infection is a significant global health concern owing to its high mortality and morbidity rates. Coagulase (Coa), a key enzyme that activates prothrombin to initiate host coagulation, has emerged as a promising target for anti-infective therapeutic approaches. This study identified sinigrin as a potent Coa inhibitor that significantly inhibited S. aureus-induced coagulation at concentration as low as 32 mg/L. Additionally, at a higher concentration of 128 mg/L, sinigrin disrupted the self-protection mechanism of S. aureus. Thermal shift and fluorescence-quenching assays confirmed the direct binding of sinigrin to the Coa protein. Molecular docking analysis predicted specific binding sites for sinigrin in the Coa molecule, and point mutation experiments highlighted the importance of Arg-187 and Asp-222 as critical binding sites for both Coa and sinigrin. In vivo studies demonstrated that the combination of sinigrin with oxacillin exhibited greater antibacterial efficacy than oxacillin alone in the treatment of S. aureus-induced pneumonia in mice. Furthermore, sinigrin was shown to reduce bacterial counts and inflammatory cytokine levels in the lung tissues of S. aureus-infected mice. In summary, sinigrin was shown to directly target Coa, resulting in the attenuation of S. aureus virulence, which suggests the potential of sinigrin as an adjuvant for future antimicrobial therapies.

The crucial relationship between vancomycin minimum inhibitory concentration and therapeutic efficacy against methicillin-resistant coagulase-negative staphylococci.

The area under the curve (AUC)/minimum inhibitory concentration (MIC) ratio was used as an indicator of the clinical efficacy of vancomycin. However, the target AUC/MIC has not been set for methicillin-resistant coagulase-negative staphylococci (MR-CNS), and the effectiveness of vancomycin in strains with high MIC is unknown. Therefore, we aimed to investigate the relationship between the vancomycin MIC and therapeutic efficacy in patients with MR-CNS bacteremia. The primary outcome was the difference in treatment failure rate when the MR-CNS vancomycin MIC was 1 or 2 µg/mL. The treatment failure rate did not significantly differ between the two groups (MIC 1 vs. MIC 2: 27.0% vs. 31.0%; p = 0.779). As a result of multivariate analysis, AUC/MIC0-24 h ≤230 was extracted as risk factor for treatment failure, suggesting the importance of a sufficient initial loading dose and early blood concentration monitoring to increase AUC/MIC0-24 h for successful treatment.

Infected Emphysematous Bullae of the Lung: A Diagnostic Challenge.

Infected emphysematous bullae of the lung present a diagnostic challenge due to their rarity and diverse clinical manifestations. We report the case of a 52-year-old female with chronic respiratory symptoms, including breathlessness and dry cough, persisting for six months. Imaging studies revealed characteristic features of infected emphysematous bullae, including large thick-walled cavities with air-fluid levels and associated parenchymal compression. Biomass exposure history and microbiological analysis, which isolated methicillin-resistant coagulase-negative Staphylococcus (MRCoNS), further supported the diagnosis. The patient responded well to antimicrobial therapy with doxycycline and linezolid. This case underscores the importance of considering environmental factors and multidisciplinary collaboration in managing complex respiratory conditions. Further research is warranted to elucidate optimal management strategies for infected emphysematous bullae of the lung.

Clinical relevance of Staphylococcus saccharolyticus detection in human samples: a retrospective cohort study.

PURPOSE: To characterize the clinical relevance of S. saccharolyticus and to identify criteria to distinguish between infection and contamination. METHODS: We retrospectively investigated clinical features of patients with S. saccharolyticus detection between June 2009 and July 2021. Based on six criteria, infection was considered likely for patients with a score from 3 to 6 points, infection was considered unlikely for patients with a score from 0 to 2 points. We performed group comparison and logistic regression to identify factors than are associated with likely infection. In addition, whole genome sequencing (WGS) of 22 isolates was performed. RESULTS: Of 93 patients in total, 44 were assigned to the group "infection likely" and 49 to the group "infection unlikely". Multiple regression analysis revealed "maximum body temperature during hospital stay" to have the strongest predictive effect on likely infection (adjusted odds ratio 4.40, 95% confidence interval 2.07-9.23). WGS revealed two different clades. Compared to isolates from clade A, isolates from clade B were more frequently associated with implanted medical devices (3/10 vs. 9/12, p = 0.046) and a shorter time to positivity (TTP) (4.5 vs. 3, p = 0.016). Both clades did neither differ significantly in terms of causing a likely infection (clade A 7/10 vs. clade B 5/12, p = 0.23) nor in median length of hospital stay (28 vs. 15.5 days, p = 0.083) and length of stay at the ICU (21 vs. 3.5 days, p = 0.14). CONCLUSION: These findings indicate that S. saccharolyticus can cause clinically relevant infections. Differentiation between infection and contamination remains challenging.

Investigation of antimicrobial resistance and antimicrobial resistance genes in Staphylococcus aureus and coagulase-negative staphylococci isolated from rabbit.

Background and Aim: Staphylococci, which inhabit skin and mucous membranes in humans and animals, are opportunistic pathogens. Coagulase-positive and coagulase-negative staphylococci (CoNS) are the two main groups. Clinical abscesses in rabbits often harbor Staphylococcus aureus and CoNS. This study estimated S. aureus and CoNS prevalence, resistance profiles, antimicrobial-resistant genes, and the accessory gene regulator (agr) group in rabbit clinical abscesses. Materials and Methods: Sixty-seven abscesses were gathered from 67 rabbits who visited Prasu-Arthorn Animal Hospital in Nakornpathom, Thailand, from January 2014 to October 2015. Thirty-four subcutaneous, 29 dental, 2 ocular, 1 mammary gland, and 1 uterine abscess were present. Conventional methods, including Gram staining, mannitol fermentation, hemolysis on blood agar, catalase testing, and coagulase production, identified and isolated S. aureus and CoNS from all abscesses. All S. aureus and CoNS isolates underwent antimicrobial susceptibility testing using the disk diffusion method. Polymerase chain reaction was used to detect the presence of blaZ, aacA-aphD, msrA, tetK, gyrA, grlA, dfrG, and cfr antimicrobial-resistant genes. Methicillin resistance was identified through the detection of a cefoxitin-resistant phenotype and the presence of mecA gene. Further investigation was conducted on the agr group of S. aureus isolates. Results: In 67 abscesses, we found 19 S. aureus isolates in 9 abscesses (13.43%) and 37 CoNS isolates in 18 abscesses (26.87%), both majorly located at subcutaneous sites. About 59.46% of CoNS isolates were methicillin-resistant compared to 5.26% of S. aureus isolates. Methicillin-resistant S. aureus (MRSA) and methicillin-resistant CoNS (MRCoNS) both displayed multidrug resistance (MDR). Both MRSA and MRCoNS expressed multiple antimicrobial resistance genes, including blaZ, aacA-aphD, gyrA, grlA, msrA, tetK, and dfrG. Approximately 73.68% of the agr groups were agr I, 15.79% were agr III, and 10.53% were agr II. Conclusion: This study found a high prevalence of MRCoNS with antimicrobial resistance and multiple antimicrobial-resistant genes in rabbits with clinical abscesses. The effectiveness of antibiotics against infections caused by such strains is a matter of concern. Owners should be educated about the importance of good hygiene practices and judicious antibiotic use to prevent widespread antimicrobial resistance.

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.

Comparative Antimicrobial Resistance and Prevalence of Methicillin Resistance in Coagulase-Positive Staphylococci from Conventional and Organic Dairy Farms in South Korea.

Bovine mastitis (BM) has caused huge economic and financial losses in the dairy industry worldwide, with Staphylococcus aureus as one of its major pathogens. BM treatment still relies on antibiotics and its extensive use often generates methicillin-resistant S. aureus (MRSA) and mupirocin-resistant S. aureus (MuRSA). This study compared the antimicrobial resistance trend in coagulase-positive Stapholococci (CoPS) isolated from BM milk in conventional and organic dairy farms and checked prevalence of MRSA and MuRSA. A total of 163 presumptive Staphylococci were isolated, wherein 11 out of 74 from 4 conventional farms (CF1, CF2, CF3, CF4) and 17 out of 89 from 3 organic farms (OF1, OF2, OF3) exhibited coagulase activity. Multiplex-PCR amplification confirmed at least one coagulase-positive isolate from CF1, CF2, CF3, CF4, and OF1 as S. aureus, denoted by the presence of the nuc gene. Three isolates from CF2 contained the mecA gene, indicating MRSA prevalence, while the MuRSA gene marker, mupA, was not detected in any of the isolates. Antimicrobial testing showed that conventional farm isolates were more resistant to antibiotics, especially ampicillin and tetracycline. This suggests a risk of developing multidrug resistance in dairy farms if antibiotic use is not properly and strictly monitored and regulated.

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.

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.