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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 -
Antimicrobial Resistance and Infection... Jul 2023This study aimed to assess the role of adenosine triphosphate (ATP) bioluminescence level monitoring for identifying reservoirs of the outbreak pathogen during two...
Using adenosine triphosphate bioluminescence level monitoring to identify bacterial reservoirs during two consecutive Enterococcus faecium and Staphylococcus capitis nosocomial infection outbreaks at a neonatal intensive care unit.
INTRODUCTION
This study aimed to assess the role of adenosine triphosphate (ATP) bioluminescence level monitoring for identifying reservoirs of the outbreak pathogen during two consecutive outbreaks caused by Enterococcus faecium and Staphylococcus capitis at a neonatal intensive care unit (NICU). The secondary aim was to evaluate the long-term sustainability of the infection control measures employed one year after the final intervention measures.
METHODS
Two outbreaks occurred during a 53-day period in two disconnected subunits, A and B, that share the same attending physicians. ATP bioluminescence level monitoring, environmental cultures, and hand cultures from healthcare workers (HCW) in the NICU were performed. Pulsed-field gel electrophoresis (PFGE) typing was carried out to investigate the phylogenetic relatedness of the isolated strains.
RESULTS
Four cases of E. faecium sepsis (patients A-8, A-7, A-9, B-8) and three cases of S. capitis sepsis (patients A-16, A-2, B-8) were diagnosed in six preterm infants over a span of 53 days. ATP levels remained high on keyboard 1 of the main station (2076 relative light unit [RLU]/100 cm) and the keyboard of bed A-9 (4886 RLU/100 cm). By guidance with the ATP results, environmental cultures showed that E. faecium isolated from the patients and from the main station's keyboard 1 were genotypically indistinguishable. Two different S. capitis strains caused sepsis in three patients. A total 77.8% (n = 7/9) of S. capitis cultured from HCW's hands were genotypically indistinguishable to the strains isolated from A-2 and A-16. The remaining 22.2% (n = 2/9) were genotypically indistinguishable to patient B-8. Three interventions to decrease the risk of bacterial transmission were applied, with the final intervention including a switch of all keyboards and mice in NICU-A and B to disinfectable ones. Post-intervention prospective monitoring up to one year showed a decrease in blood culture positivity (P = 0.0019) and catheter-related blood stream infection rate (P = 0.016) before and after intervention.
CONCLUSION
ATP monitoring is an effective tool in identifying difficult to disinfect areas in NICUs. Non-medical devices may serve as reservoirs of pathogens causing nosocomial outbreaks, and HCWs' hands contribute to bacterial transmission in NICUs.
Topics: Infant, Newborn; Humans; Cross Infection; Intensive Care Units, Neonatal; Staphylococcus capitis; Enterococcus faecium; Staphylococcal Infections; Phylogeny; Prospective Studies; Infant, Premature; Sepsis; Disease Outbreaks
PubMed: 37443079
DOI: 10.1186/s13756-023-01273-5 -
Applied Microbiology Sep 1975The districution of Staphylococcus and Micrococcus species and associated coryneform bacteria, Acinetobacter, Klebsiella, Enterobacter, Bacillus, and Streptomyces on...
The districution of Staphylococcus and Micrococcus species and associated coryneform bacteria, Acinetobacter, Klebsiella, Enterobacter, Bacillus, and Streptomyces on skin was determined during October 1971 from samples collected on persons living in North Carolina and New Jersey. Persistence of these organisms on skin was estimated in temporal studies conducted during the period from June 1971 to June 1972 on persons living in North Carolina. Staphylococci and coryneforms were the most predominant and persistent bacteria isolated from the nares and axillae. Staphylococci, coryneforms, micrococci, and Bacillus were the most predominant and persistent bacteria isolated from the head, legs, and arms. Acinetobacters were most frequently isolated during the warmer months of the years. Staphylococcus aureus and S. epidermidis were the most predominant and persistent staphylococci isolated from the nares, whereas S. epidermidis and S. hominis were the most predominant and persistent staphylocicci isolated from the axillae, head, legs, and arms. S. capitis was often isolated from the head and arms and S. haemolyticus was often isolated from the head, legs, and arms. S. simulans, S. xylosus, S. cohnii, S. saprophyticus, S. warneri, and an unclassified coagulase-positive species were only occasionally isolated from skin. Micrococcus luteus was the most predominant and persistent Micrococcus isolated from skin and preferred regions of the head, legs, and arms. M. varians was the second most frequent Micrococcus isolated. M. lylae, M. sedentarius, M. roseus, M. kristinae, and M. nishinomiyaensis were only occasionally isolated from skin. M. lylae was most frequently isolated during the colder months of the years.
Topics: Acinetobacter; Actinomycetales; Aerobiosis; Arm; Axilla; Bacillus; Bacteria; Enterobacter; Head; Humans; Klebsiella; Leg; Micrococcus; New Jersey; North Carolina; Nose; Seasons; Skin; Species Specificity; Staphylococcus; Streptomyces
PubMed: 810086
DOI: 10.1128/am.30.3.381-395.1975 -
Brazilian Journal of Microbiology :... Dec 2022This research aimed to identify the diversity of bacterial species of the genus Staphylococcus spp. in subclinical mastitis in dairy herds in the state of Piauí,...
This research aimed to identify the diversity of bacterial species of the genus Staphylococcus spp. in subclinical mastitis in dairy herds in the state of Piauí, Northeastern Brazil, and to evaluate the phenotypic and genotypic resistance profile. Samples were obtained from a total of 17 dairy farms, amounting to 321 positive samples in the California Mastitis Test. Staphylococcus spp. were identified by matrix-assisted laser desorption ionization time-of-flight mass spectroscopy. Subsequently, an antibiogram was performed, and a polymerase chain reaction was carried out to screen for resistance genes in the isolates. Among all the isolates, 59.45% (110/185) belonged to the Staphylococcus genus. Moreover, the following Staphylococcus spp. were identified Staphylococcus aureus, 68.1% (75/110); Staphylococcus chromogenes, 12.7% (14/110); Staphylococcus epidermidis, 5.4% (6/110); Staphylococcus sciuri, 4.5% (5/110); Staphylococcus warneri, 2.7% (3/110); Staphylococcus haemolyticus, 1.8% (2/110); Staphylococcus hominis, 1.8% (2/110); Staphylococcus arlettae, 0.9% (1/110); Staphylococcus capitis, 0.9% (1/110); and Staphylococcus gallinarum, 0.9% (1/110). The antibiogram showed a high frequency of resistance to penicillin and ampicillin, 70.0% (77/110) and 61.8% (68/110), respectively, and a low frequency of resistance to gentamicin and vancomycin, 10.9% (12/110) and 11.8% (13/110), respectively. In the genotypic tests for the different species of Staphylococcus spp., the occurrence of the blaZ gene was observed in 60.9% (67/110) of the isolates, followed by tetL and tetM, both with 20.0% (22/110) each, and the mecA and vanB genes were detected in 0.9% (1/110) of the samples. The identification of all Staphylococcus species isolated from subclinical mastitis cases and the phenotypic and genotypic resistance characterization in these isolates is of great importance for dairy farming in the state of Piauí, as well as for public health.
Topics: Cattle; Animals; Female; Humans; Mastitis, Bovine; Methicillin-Resistant Staphylococcus aureus; Brazil; Staphylococcus; Staphylococcal Infections; Microbial Sensitivity Tests; Milk; Anti-Bacterial Agents
PubMed: 36074251
DOI: 10.1007/s42770-022-00822-1 -
Journal of Pathogens 2020species are considered as one of the major pathogens causing outbreaks of food poisoning. The aim of this work was to assess the toxinogenic and antibiotic...
species are considered as one of the major pathogens causing outbreaks of food poisoning. The aim of this work was to assess the toxinogenic and antibiotic susceptibility profiles of the strains of spp isolated from three types of fermented dairy products (yoghourt, millet , and couscous ). The isolation of the strains was performed on selective media, and their identification was done using biochemical and molecular methods. The susceptibility at 15 antibiotics tested was assessed using the disc diffusion method. The immunodiffusion method was used to evaluate the toxin (luk-E/D, luk-S/F, ETA, and ETB) production. Biofilm formation was qualitatively researched on microplates. Less than half (42.77%) of the collected samples were contaminated with spp. The yoghourt and millet samples collected in the afternoon were more contaminated than those collected in the morning. The , and strains, respectively, were the most present. was the only coagulase-positive species identified in our samples. The highest resistance to antibiotics was observed with penicillin (100%) irrespective of the nature of the sample. strains were highly (71.4%) resistant to methicillin. The strains were the most biofilm-forming (27.6%), followed by strains. Panton and Valentine's leukocidin (luk-S/F) was produced by only strains at a rate of 8.33%. Only coagulase-negative (CNS) produced Luk-E/D. The high rates of contamination indicate bad hygiene quality during the production and distribution of dairy products. It is, therefore, necessary to improve the quality of fermented milk products.
PubMed: 33204534
DOI: 10.1155/2020/7938149 -
Frontiers in Microbiology 2021Whether terrestrial life can withstand the martian environment is of paramount interest for planetary protection measures and space exploration. To understand microbial...
Whether terrestrial life can withstand the martian environment is of paramount interest for planetary protection measures and space exploration. To understand microbial survival potential in Mars-like conditions, several fungal and bacterial samples were launched in September 2019 on a large NASA scientific balloon flight to the middle stratosphere (∼38 km altitude) where radiation levels resembled values at the equatorial Mars surface. Fungal spores of and bacterial cells of , subsp. , and sp. MASE-IM-9 were launched inside the MARSBOx (Microbes in Atmosphere for Radiation, Survival, and Biological Outcomes Experiment) payload filled with an artificial martian atmosphere and pressure throughout the mission profile. The dried microorganisms were either exposed to full UV-VIS radiation (UV dose = 1148 kJ m) or were shielded from radiation. After the 5-h stratospheric exposure, samples were assayed for survival and metabolic changes. Spores from the fungus and cells from the Gram-(-) bacterium were the most resistant with a 2- and 4-log reduction, respectively. Exposed sp. MASE-IM-9 was completely inactivated (both with and without UV exposure) and subsp. only survived the UV shielded experimental condition (3-log reduction). Our results underscore a wide variation in survival phenotypes of spacecraft associated microorganisms and support the hypothesis that pigmented fungi may be resistant to the martian surface if inadvertently delivered by spacecraft missions.
PubMed: 33692763
DOI: 10.3389/fmicb.2021.601713 -
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 -
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 -
Nature Communications Jul 2022Staphylococcus capitis, which causes bloodstream infections in neonatal intensive care units, is a common cause of healthcare-associated infections. Thus, a standardized...
Staphylococcus capitis, which causes bloodstream infections in neonatal intensive care units, is a common cause of healthcare-associated infections. Thus, a standardized high-resolution typing method to document the transmission and dissemination of multidrug-resistant S. capitis isolates is required. We aimed to establish a core genome multilocus sequence typing (cgMLST) scheme to surveil S. capitis. The cgMLST scheme was defined based on primary and validation genome sets and tested with outbreaks of linezolid-resistant isolates and a validation set. Phylogenetic analysis was performed to investigate the population structure and compare it with the result of cgMLST analysis. The S. capitis population consists of 1 dominant, NRCS-A, and 4 less common clones. In this work, a multidrug-resistant clone (L clone) with linezolid resistance is identified. With the features of type III SCCmec and multiple copies of mutations of G2576T and C2104T in the 23S rRNA, the L clone has been spreading silently across China.
Topics: Anti-Bacterial Agents; Humans; Infant, Newborn; Linezolid; Methicillin-Resistant Staphylococcus aureus; Multilocus Sequence Typing; Phylogeny; Staphylococcal Infections; Staphylococcus capitis
PubMed: 35869070
DOI: 10.1038/s41467-022-31908-x