SEARCH · PubMed Health

Results for “Staphylococcus chromogenes”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

6 recordsLinked to original sources

PubMed2026

Genomic and food-safety evaluation of Staphylococcus chromogenes in Chinese dairy milk.

Non-aureus staphylococci and mammaliicocci (NASM) cause mastitis and may contaminate milk and dairy products. Milk samples (n = 1916) from cows with subclinical or clinical mastitis (SCM and CM, respectively) were collected from 28 large-scale (> 500 lactating cows) Chinese dairy farms. Overall, 999 NASM isolates representing 19 species were identified by MALDI-TOF MS and cpn60 sequencing, with Staphylococcuschromogenes, Mammaliicoccus sciuri and Staphylococcus haemolyticus being most prevalent. Antimicrobial resistance (AMR) was determined with disc diffusion; non-susceptible to penicillin was most common (SCM, 30% and CM, 29%) whereas cefoxitin non-susceptible NASM accounted for 8-10% of isolates; among these, 12.5% carried mecA but none carried mecC. Galleria mellonella was used to assess virulence of 78 strains of S. chromogenes, a dominant species; subsequently, 32 strains, representing higher- and lower-virulence in the Galleria model, were selected for whole-genome sequencing and comparative genomics. S. chromogenes isolates from CM had higher virulence (p < 0.05) than those from SCM. The 32 genomes comprised 20 sequence types, indicating high genetic diversity. No robust genomic marker of Galleria virulence phenotype was identified in this selected WGS subset. Acquired resistance genes (n = 5) were detected, including a first report of fusC in S. chromogenes; the fusC-positive isolate had an elevated fusidic acid MIC (8 mg/L). Although S. chromogenes persisted in milk at 4 °C, pasteurization (64 °C for 30 min) reduced viable counts to below detection. This study provided new insights into the prevalence, AMR, genomic diversity, and dairy-chain relevance of milk-derived NASM, particularly S. chromogenes. However, the genomic findings were based on an intentionally selected WGS subset and should be interpreted as hypothesis-generating rather than population-representative.

Animals↗

PubMed1979

Identification of clumping-factor-negative staphylococci isolated from cows' udders.

Identification to species level was attempted on a collection of 954 cultures of catalase-positive, clumping-factor- and beta-haemolysin-negative Gram-positive cocci isolated from teats and milk of cows. Eighty-seven per cent of the strains were identified as Staphylococcus xylosus, S epidermidis, S sciuri, S haemolyticus, S hyicus subsp hyicus and chromogenes, S simulans and S cohnii. Nine per cent of the collection belonged to another group which could not be identified with any of the known Staphylococcus species. Many of the strains of this group and also part of the S epidermidis and S hyicus subsp chromogenes strains examined showed various degrees of growth enhancement on certain media when fatty substances were added. Only nine strains were classified as Micrococcus. A scheme for the identification of coagulase-negative staphylococci from cows' milk is proposed.

Animals↗

PubMed2026

Metal-organic frameworks nanozyme-integrated portable microneedle patch for visual bacterial monitoring in meat.

Foodborne microbial contamination is a major global health concern, with conventional methods often being time-consuming and complex. Herein, we developed a novel portable biosensor by integrating microneedle patch technology and a metal-organic framework (Fe/Cu-NBDC MOF) nanozyme, enabling rapid, on-site, visual detection of bacteria in meat. The sensing system works by encapsulating aptamer-functionalized MOF nanozymes within a hydrogel patch, where their catalytic sites are initially blocked by the aptamer. In the presence of Staphylococcus aureus (S. aureus) as the target, the specific aptamer's binding to bacteria exposes numerous catalytic sites, further activating the chromogenic reaction of the tetramethylbenzidine‑hydrogen peroxide (TMB-H₂O₂) system, enabling visual detection of S. aureus. The biosensor demonstrates a detection limit of 82 CFU/mL with excellent specificity to successfully apply to commercial mutton. By integrating sampling, enrichment, and visual detection into a single compact device, this platform offers a practical, efficient solution for rapid on-site screening of foodborne pathogens.

Biosensing Techniques↗

PubMed1979

Chromogenic cephalosporin spot test to detect beta-lactamase in clinically significant bacteria.

lactamase production. Reacteroides melaniongenicus, 14

Bacteria↗

PubMed1977

On the diagnosis of coagulase-negative staphylococci with emphasis on Staphylococcus saprophyticus.

This study concerns the diagnosis of coagulase-negative staphylococci, with special emphasis on novobiocin-resistant species, vis S. saprophyticus, S. cohnii and S. xylosus. Disc diffusion tests for novobiocin were found useful in the differential diagnosis of coagulase-negative staphylococci isolated from urine specimens, but not from pus and blood cultures. We report on the resistance of S. saprophyticus to nalidixic acid and the use of this characteristic in the diagnosis of coagulase-negative staphylococci known to be novobiocin-sensitive, but which have subsequently acquired resistance to novobiocin. The results of different tests for betalactamase production in S. saprophyticus are presented. "Clover leaf" tests suggested such a production in about half of the strains studied, while no strain produced betalactamase as indicated by tests using chromogenic cephalosporin or benzylpenicillin in capillary tube tests. -The failure of tests for nitrate reduction, glucose consumption and of cultrues of urine on MacConkey's agar in the diagnosis of urinary tract infections caused by S. saprophyticus, is documented. The concept "significant bacteriuria" in the diagnosis of S. saprophyticus infections of the urinary tract above the bladder neck is also considered.

Bacteriological Techniques↗

PubMed1978

Irreversible effects of serum proteins on beta-lactam antibiotics.

The chromogenic cephalosporin nitrocefin (87/312) demonstrates rapid and visible instability to serum from many species. This phenomenon was distinct from serum binding, being significantly slower. Destruction of another cephalosporin, 10485, by serum appeared to account for some anomalous results during investigation into its human pharmacokinetics. Many cephalosporins of very different structures also showed serum instability, unrelated to their degrees of serum binding as measured by plate assay. Extrapolation could not be made from one species to another with regard to either binding or instability. Small changes in the chemical structures of the 3- and 7-substituents of the cephalosporins made profound changes in their susceptibility to serum attack. The decomposition is pH dependent, occurring more slowly at acid pH, and is due to a high-molecular-weight component of serum that resists boiling for several minutes. Isoelectric focusing of serum from several animal species gave various species-specific bands that decomposed nitrocefin. The inactivation of nitrocefin was not entirely parallel with that of 10485 and was inhibited by it. All other beta-lactam compounds tested also inhibited the reaction, much greater concentrations usually being necessary when the inhibitor was stable to serum. The complex that causes breakdown of the beta-lactam compounds is not necessarily the same as the one causing serum binding. It is postulated that serum may affect most other beta-lactam antibiotics in a similar way, although in most cases, this only occurs to a very slight extent.

Bacillus subtilis↗