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Frontiers in Microbiology 2020is an opportunistic pathogen often implicated in bloodstream infections in the neonatal intensive care unit (NICU). This is assisted by its ability to form biofilms on...
is an opportunistic pathogen often implicated in bloodstream infections in the neonatal intensive care unit (NICU). This is assisted by its ability to form biofilms on indwelling central venous catheters (CVC), which are highly resistant to antibiotics and the immune system. We sought to understand the fundamentals of biofilm formation by in the NICU, using seventeen clinical isolates including the endemic NRCS-A clone and assessing nine commercial and two modified polystyrene surfaces. clinical isolates from the NICU initiated biofilm formation only in response to hyperosmotic conditions, followed by a developmental progression driven by expression to establish mature biofilms, with polysaccharide being their major extracellular polymer substance (EPS) matrix component. Physicochemical features of the biomaterial surface, and in particular the level of the element oxygen present on the surface, significantly influenced biofilm development of . A lack of highly oxidized carbon species on the surface prevented the immobilization of EPS and the formation of mature biofilms. This information provides guidance in regard to the preparation of hyperosmolar total parenteral nutrition and the engineering of CVC surfaces that can minimize the risk of catheter-related bloodstream infections caused by in the NICU.
PubMed: 32477314
DOI: 10.3389/fmicb.2020.00920 -
Journal of Clinical Microbiology Dec 2020Testing of staphylococci other than (SOSA) for -mediated resistance is challenging. Isolates of , , , and were evaluated by cefoxitin and oxacillin broth microdilution...
Evaluation of Surrogate Tests for the Presence of -Mediated Methicillin Resistance in Staphylococcus capitis, Staphylococcus haemolyticus, Staphylococcus hominis, and Staphylococcus warneri.
Testing of staphylococci other than (SOSA) for -mediated resistance is challenging. Isolates of , , , and were evaluated by cefoxitin and oxacillin broth microdilution (BMD), disk diffusion (DD), and PBP2a immunoassay, and the results were compared to PCR results. No phenotypic susceptibility test correlated well with PCR results across all species, although the PBP2a immunoassay yielded 100% correlation. Oxacillin BMD testing by current Clinical and Laboratory Standards Institute (CLSI) SOSA breakpoints led to 2.1% very major errors (VMEs) and 7.1% major errors (ME). Adjusting this breakpoint up by a dilution (susceptible, ≤0.5 μg/ml; resistant, ≥1.0 μg/ml) led to 2.8% VMEs and 0.3% MEs. Among species evaluated, had unacceptable VMEs with this new breakpoint (6.4%), as did (4.0%). MEs were acceptable by this new breakpoint, ranging from 0 to 1.2%. Oxacillin DD yielded high ME rates (20.7 to 21.7%) using CLSI or European Committee on Antimicrobial Susceptibility Testing breakpoints. VMEs ranged from 0 to 5.3%. Cefoxitin BMD led to 4.9% VMEs and 1.6% MEs. Cefoxitin DD performed best when interpreted with the CLSI SOSA breakpoint, with 1.0% VMEs and 2.9% MEs. This study led CLSI to adjust the oxacillin MIC breakpoints for SOSA. Laboratories should be aware that no individual phenotypic test correlates well across all species of SOSA with PCR results. Molecular testing for or evaluation for PBP2a is the preferred approach.
Topics: Anti-Bacterial Agents; Bacterial Proteins; Cefoxitin; Humans; Methicillin Resistance; Microbial Sensitivity Tests; Oxacillin; Penicillin-Binding Proteins; Staphylococcal Infections; Staphylococcus; Staphylococcus capitis; Staphylococcus haemolyticus; Staphylococcus hominis
PubMed: 33115842
DOI: 10.1128/JCM.02290-20 -
Pathogens (Basel, Switzerland) Apr 2022is a major bacterial species that contaminates retail meat products. The objective of this study was to clarify the prevalence, antimicrobial resistance and genetic...
is a major bacterial species that contaminates retail meat products. The objective of this study was to clarify the prevalence, antimicrobial resistance and genetic determinants of / species in retail ground meat in Japan. From a total of 146 retail ground meat samples (chicken, pork, mixed beef/pork) purchased during a 5-month period, 10 and 112 isolates of coagulase-negative staphylococcus (CoNS)/ comprising 20 species were recovered. isolates were classified into five genetic types, i.e., -IIa/ST5, -VIc/ST352 (CC97), -VIIb/ST398, -Xa/ST15, and -XIc/ST9, which were all related to those of livestock-associated clones. All the staphylococcal isolates were -negative and mostly susceptible to all the antimicrobials tested, except for ampicillin among (resistance proportion; 50%). Among CoNS, the fosfomycin resistance gene was prevalent (30/112; 26.8%), primarily in , , and . Phylogenetic analysis of revealed the presence of seven clusters, showing broad diversity with 65-81% identity among different clusters. In the CoNS isolates from ground meat samples, was assigned into three clusters, and harbored the most divergent with three genetic groups. These findings suggested the circulation of multiple -carrying plasmids among some CoNS species.
PubMed: 35456144
DOI: 10.3390/pathogens11040469 -
Pathogens (Basel, Switzerland) Jul 2022The spread of methicillin resistance and virulence among staphylococci in the community poses a public health concern. In this study, we investigated the prevalence of...
The spread of methicillin resistance and virulence among staphylococci in the community poses a public health concern. In this study, we investigated the prevalence of species colonizing the oral cavity and hand (skin) of healthy university students and their phenotypic and genetic characteristics in northern Japan. Among a total of 332 subjects, 6 and 110 methicillin-resistant and susceptible (MRSA and MSSA, respectively) isolates were recovered from 105 subjects. MRSA isolates were genotyped as CC5, CC8, CC45, and CC59 with SCC-IIa or IV, among which an isolate of ST6562 (single-locus variant of ST8) harbored SCC-IVa, PVL genes and ACME-I, which are the same traits as the USA300 clone. ST1223 was isolated from the oral cavity and hand of a single student. Coagulase-negative (CoNS) was recovered from 154 subjects (172 isolates), and classified into 17 species, with being the most common (38%), followed by (24%) and (15%), including nine -positive isolates. was differentiated into seven clusters/subclusters, and genetic factors associated with the NRCS-A clone (, , ) were detected in 10-21% of isolates. The colonization of the USA300-like MRSA variant and with the traits of the NRCS-A clone in healthy individuals was noteworthy.
PubMed: 36014970
DOI: 10.3390/pathogens11080849 -
Cureus Jun 2021Described as primarily an opportunistic pathogen, is primarily found as normal flora of the human skin but has been defined in literature as being a rare cause of...
Described as primarily an opportunistic pathogen, is primarily found as normal flora of the human skin but has been defined in literature as being a rare cause of infective endocarditis. We present a case of an otherwise healthy 65-year-old male who presented to our institution with symptoms similar to septic emboli. Blood cultures were obtained and ultimately grew in both bottles with repeat cultures one day later confirming the growth. A transthoracic echocardiogram was performed showing an ejection fraction of 60-65% and a thickened mitral value with mild-to-moderate mitral regurgitation. He was ultimately treated with IV cefazolin and improved with symptom resolution in outpatient follow-up. pathogenesis continues to be poorly understood, yet aggressive management with surgery and antibiotics has proven to decrease morbidity and mortality.
PubMed: 34290924
DOI: 10.7759/cureus.15738 -
Global Pediatric Health 2019This case report describes an unusual invasive infection with , in a child with a history of repaired congenital heart disease and an acute presentation of...
This case report describes an unusual invasive infection with , in a child with a history of repaired congenital heart disease and an acute presentation of osteomyelitis. Coagulase-negative staphylococci are rare causes of osteomyelitis without an implanted device in the bone and, as such, should prompt evaluation for associated infections that may be contributing to the unusual presentation. Additionally, this case highlights the importance of considering methicillin heteroresistance in staphylococcal infections when the clinical course is not proceeding as expected.
PubMed: 30886881
DOI: 10.1177/2333794X19833736 -
Access Microbiology 2023To review the epidemiology of coagulase-negative staphylococci (CoNS) in England over the recent 12 year period.
OBJECTIVE
To review the epidemiology of coagulase-negative staphylococci (CoNS) in England over the recent 12 year period.
METHODS
Laboratory-confirmed CoNS reported from sterile sites in patients in England to the UK Health Security Agency (UKHSA) between 2010 and 2021 were extracted from the national laboratory database and analysed.
RESULTS
Overall, 668 857 episodes of CoNS were reported. Unspeciated CoNS accounted for 56 % (374 228) of episodes, followed by (26 %; 174 050), (6.5 %; 43 501) and (3.9 %; 25 773). Unspeciated CoNS increased by 8.2 % (95 % CI, 7.1-9.3) annually between 2010 and 2016, then decreased annually by 6.4 % (95 % CI: -4.8 to -7.9) until 2021. Speciated CoNS increased by 47.6 % (95 % CI, 44.5-50.9) annually between 2010 and 2016 and increased annually by 8.9 % (95 % CI: 5.1 to 12.8) until 2021. Antimicrobial susceptibility profiles differed by species.
CONCLUSIONS
Reports of CoNS from normally sterile body sites in patients in England increased between 2010 and 2016 and remained stable between 2017 and 2021. There has been a striking improvement in species-level identification of CoNS in recent years. Monitoring trends in CoNS epidemiology is crucial for development of observational and clinical intervention studies on individual species.
PubMed: 37424540
DOI: 10.1099/acmi.0.000491.v3 -
Infection and Drug Resistance 2020Bacteria undergo adaptive mutation in the host. However, the specific effect of antimicrobial use on bacterial evolution and genome mutations related to bacterial...
BACKGROUND
Bacteria undergo adaptive mutation in the host. However, the specific effect of antimicrobial use on bacterial evolution and genome mutations related to bacterial survival within a patient is unclear.
MATERIALS AND METHODS
Three strains were sequentially isolated from cerebrospinal fluid of a clinical inpatient. Antimicrobial susceptibility, growth rate, biofilm formation and whole blood survival of these strains were measured. Relative fitness was calculated. The virulence was examined in the model. Whole-genome sequencing and in silico analysis were performed to explore the genetic mechanisms of the changes in antimicrobial resistance phenotype. Hypothetical proteins are cloned, expressed and characterized by detection the susceptibility to gentamycin.
RESULTS
The first isolate was susceptible to rifampin (MIC=0.25 μg/mL), resistant to gentamicin (MIC=16 μg/mL), while the later two isolates were resistant to rifampin (MIC >64 μg/mL), susceptible to gentamicin (MIC=4 μg/mL). For the latter two strains, compared to the first, frameshift mutation in a hypothetical protein encoding gene and base substitutions (in genes s and ) were discovered. The mutation of gene caused rifampicin resistance. Mutations in and gene are associated with changes in other biological traits. Amino acid sequence-based structure and function identification of the hypothetical protein indicated that a mutation in the encoding gene might be associated with altered aminoglycoside susceptibility. Growth curve showed that the later two isolates grew faster than the first isolate with a positive fitness advantage of 13.5%, and 14.8%, accordingly. Biofilm form ability and whole blood survival of the derivative mutants were also enhanced. No significant differences of virulence in the model were observed.
CONCLUSION
We report here for the first time that short-term clinical antibiotic use was associated with resistance mutations, collateral sensitivity, and positive in vivo fitness advantages to during infection.
PubMed: 32636655
DOI: 10.2147/IDR.S254141 -
BioRxiv : the Preprint Server For... Jun 2023Human skin is stably colonized by a distinct microbiota that functions together with epidermal cells to maintain a protective physical barrier. , a prominent genus of...
Human skin is stably colonized by a distinct microbiota that functions together with epidermal cells to maintain a protective physical barrier. , a prominent genus of the skin microbiota, participates in colonization resistance, tissue repair, and host immune regulation in strain specific manners. To unlock the potential of engineering skin microbial communities, we aim to fully characterize the functional diversity of this genus within the context of the skin environment. We conducted metagenome and pan-genome analyses of isolates obtained from distinct body sites of healthy volunteers, providing a detailed biogeographic depiction of staphylococcal species that colonize our skin. , and were the most abundant species present in all volunteers and were detected at all body sites. Pan-genome analysis of these three species revealed that the genus-core was dominated by central metabolism genes. Species-specific core genes were enriched in host colonization functions. The majority (~68%) of genes were detected only in a fraction of isolate genomes, underscoring the immense strain-specific gene diversity. Conspecific genomes grouped into phylogenetic clades, exhibiting body site preference. Each clade was enriched for distinct gene-sets that are potentially involved in site tropism. Finally, we conducted gene expression studies of select isolates showing variable growth phenotypes in skin-like medium. expression revealed extensive intra- and inter-species gene expression variation, substantially expanding the functional diversification within each species. Our study provides an important resource for future ecological and translational studies to examine the role of shared and strain-specific staphylococcal genes within the skin environment.
PubMed: 37503282
DOI: 10.1101/2023.06.22.546190 -
Genome Biology and Evolution Sep 2021Members of the gram-positive bacterial genus Staphylococcus have historically been classified into coagulase-positive Staphylococcus (CoPS) and coagulase-negative...
Members of the gram-positive bacterial genus Staphylococcus have historically been classified into coagulase-positive Staphylococcus (CoPS) and coagulase-negative Staphylococcus (CoNS) based on the diagnostic presentation of the coagulase protein. Previous studies have noted the importance of horizontal gene transfer (HGT) and recombination in the more well-known CoPS species Staphylococcus aureus, yet little is known of the contributions of these processes in CoNS evolution. In this study, we aimed to elucidate the phylogenetic relationships, genomic characteristics, and frequencies of HGT in CoNS, which are now being recognized as major opportunistic pathogens of humans. We compiled a data set of 1,876 publicly available named CoNS genomes. These can be delineated into 55 species based on allele differences in 462 core genes and variation in accessory gene content. CoNS species are a reservoir of transferrable genes associated with resistance to diverse classes of antimicrobials. We also identified nine types of the mobile genetic element SCCmec, which carries the methicillin resistance determinant mecA. Other frequently transferred genes included those associated with resistance to heavy metals, surface-associated proteins related to virulence and biofilm formation, type VII secretion system, iron capture, recombination, and metabolic enzymes. The highest frequencies of receipt and donation of recombined DNA fragments were observed in Staphylococcus capitis, Staphylococcus caprae, Staphylococcus hominis, Staphylococcus haemolyticus, and members of the Saprophyticus species group. The variable rates of recombination and biases in transfer partners imply that certain CoNS species function as hubs of gene flow and major reservoir of genetic diversity for the entire genus.
Topics: Anti-Bacterial Agents; Coagulase; Gene Transfer, Horizontal; Humans; Microbial Sensitivity Tests; Phylogeny; Staphylococcal Infections; Staphylococcus
PubMed: 34498042
DOI: 10.1093/gbe/evab206