-
New Microbes and New Infections Sep 2020Coagulase-negative staphylococci (CoNS) are recognized as comprising the main part of human normal microbiota and are rarely associated with severe and intensive... (Review)
Review
Coagulase-negative staphylococci (CoNS) are recognized as comprising the main part of human normal microbiota and are rarely associated with severe and intensive infections. However, these organisms can cause a number of infections in humans, especially immunocompromised patients and neonates. Bacterial meningitis, as an important and acute infection in the central nervous system, is still a major global health challenge and a serious infectious disease, causing a high rate of mortality and morbidity. CoNS as causative agents of meningitis are generally related to trauma or direct implantation of foreign bodies and the presence of a cerebrospinal fluid shunt. Numerous epidemiologic and clinical studies have shown that different CoNS isolates such as and are more frequently associated with meningitis. This study attempts to determine the role of CoNS in meningitis and reviews the reported cases of meningitis induced by CoNS from the year 2000 to 2020 in the literature.
PubMed: 33014383
DOI: 10.1016/j.nmni.2020.100755 -
Frontiers in Microbiology 2022Previous studies have reported that spaceflight specific conditions such as microgravity lead to changes in bacterial physiology and resistance behavior including...
Previous studies have reported that spaceflight specific conditions such as microgravity lead to changes in bacterial physiology and resistance behavior including increased expression of virulence factors, enhanced biofilm formation and decreased susceptibility to antibiotics. To assess if spaceflight induced physiological changes can manifest in human-associated bacteria, we compared three spaceflight relevant isolates (DSM 111179, ISS; DSM 31028, clean room; DSM 113836; artificial gravity bedrest study) with the type strain (DSM 20326). We tested the three strains regarding growth, colony morphology, metabolism, fatty acid and polar lipid pattern, biofilm formation, susceptibility to antibiotics and survival in different stress conditions such as treatment with hydrogen peroxide, exposure to desiccation, and irradiation with X-rays and UV-C. Moreover, we sequenced, assembled, and analyzed the genomes of all four strains. Potential genetic determinants for phenotypic differences were investigated by comparative genomics. We found that all four strains show similar metabolic patterns and the same susceptibility to antibiotics. All four strains were considered resistant to fosfomycin. Physiological differences were mainly observed compared to the type strain and minor differences among the other three strains. The ISS isolate and the bedrest study isolate exhibit a strong delayed yellow pigmentation, which is absent in the other two strains. Pigments were extracted and analyzed by UV/Vis spectroscopy showing characteristic carotenoid spectra. The ISS isolate showed the highest growth rate as well as weighted average melting temperature (WAMT) of fatty acids (41.8°C) of all strains. The clean room isolate showed strongest biofilm formation and a high tolerance to desiccation. In general, all strains survived desiccation better in absence of oxygen. There were no differences among the strains regarding radiation tolerance. Phenotypic and genomic differences among the strains observed in this study are not inevitably indicating an increased virulence of the spaceflight isolate. However, the increased growth rate, higher WAMT and colony pigmentation of the spaceflight isolate are relevant phenotypes that require further research within the human spaceflight context. We conclude that combining genetic analysis with classical microbiological methods allows the detailed assessment of the potential threat of bacteria in highly regulated and extreme environments such as spaceflight environments.
PubMed: 36406458
DOI: 10.3389/fmicb.2022.1007143 -
Microbiology Spectrum Dec 2022The clone Staphylococcus capitis NRCS-A is responsible for late-onset sepsis in neonatal intensive care units (NICUs) worldwide. Over time, this clone has evolved into...
The clone Staphylococcus capitis NRCS-A is responsible for late-onset sepsis in neonatal intensive care units (NICUs) worldwide. Over time, this clone has evolved into three subgroups that are increasingly adapted to the NICU environment. This study aimed to decipher the mechanisms involved in NRCS-A persistence in NICUs. Twenty-six strains belonging to each of the three NRCS-A clone subgroups and two other non-NRCS-A groups from neonates (alpha clone) or from adult patients ("other strains") were compared based on growth kinetics and ability to form biofilm as well as tolerance to desiccation and to different disinfectants. biofilm formation was enhanced in rich medium and decreased under conditions of nutrient stress for all strains. However, under conditions of nutrient stress, NRCS-A strains presented an enhanced ability to adhere and form a thin biofilm containing more viable and culturable bacteria (mean 5.7 log CFU) than the strains from alpha clone (mean, 1.1 log CFU) and the "other strains" (mean, 4.2 log CFU) ( < 0.0001). The biofilm is composed of bacterial aggregates with a matrix mainly composed of polysaccharides. The NRCS-A clone also showed better persistence after a 48-h desiccation. However, disinfectant tolerance was not enhanced in the NRCS-A clone in comparison with that of strains from adult patients. In conclusion, the ability to form biofilm under nutrient stress and to survive desiccation are two major advantages for clone NRCS-A that could explain its ability to persist and settle in the specific environment of NICU settings. Neonatal intensive care units (NICUs) host extremely fragile newborns, including preterm neonates. These patients are very susceptible to nosocomial infections, with coagulase-negative staphylococci being the species most frequently involved. In particular, a Staphylococcus capitis clone named NRCS-A has emerged worldwide specifically in NICUs and is responsible for severe nosocomial sepsis in preterm neonates. This clone is specifically adapted to the NICU environment and is able to colonize and maintain on NICU surfaces. The present work explored the mechanisms involved in the persistence of the NRCS-A clone in the NICU environment despite strict hygiene measures. The ability to produce biofilm under nutritional stress and to resist desiccation appear to be the two main advantages of NRCS-A in comparison with other strains. These findings are pivotal to provide clues for subsequent development of targeted methods to combat NRCS-A and to stop its dissemination.
Topics: Adult; Infant, Newborn; Humans; Staphylococcus capitis; Anti-Bacterial Agents; Staphylococcal Infections; Intensive Care Units, Neonatal; Disinfectants; Desiccation; Sepsis
PubMed: 36409142
DOI: 10.1128/spectrum.04215-22 -
Microbial Genomics Oct 2023is a frequent cause of late-onset sepsis in neonates admitted to Neonatal Intensive Care Units (NICU). One clone of , NRCS-A has been isolated from NICUs globally...
is a frequent cause of late-onset sepsis in neonates admitted to Neonatal Intensive Care Units (NICU). One clone of , NRCS-A has been isolated from NICUs globally although the reasons for the global success of this clone are not well understood.We analysed a collection of colonising babies admitted to two NICUs, one in the UK and one in Germany as well as corresponding pathological clinical isolates. Genome analysis identified a population structure of three groups; non-NRCS-A isolates, NRCS-A isolates, and a group of 'proto NRCS-A' - isolates closely related to NRCS-A but not associated with neonatal infection. All bloodstream isolates belonged to the NRCS-A group and were indistinguishable from strains carried on the skin or in the gut. NRCS-A isolates showed increased tolerance to chlorhexidine and antibiotics relative to the other as well as enhanced ability to grow at higher pH values. Analysis of the pangenome of 138 isolates identified characteristic and genes in both the NRCS-A and proto groups. A CRISPR-cas system was only seen in NRCS-A isolates which also showed enrichment of genes for metal acquisition and transport.We found evidence for transmission of NRCS-A within NICU, with related isolates shared between babies and multiple acquisitions by some babies. Our data show NRCS-A strains commonly colonise uninfected babies in NICU representing a potential reservoir for potential infection. This work provides more evidence that adaptation to survive in the gut and on skin facilitates spread of NRCS-A, and that metal acquisition and tolerance may be important to the biology of NRCS-A. Understanding how NRCS-A survives in NICUs can help develop infection control procedures against this clone.
Topics: Infant; Infant, Newborn; Adult; Humans; Staphylococcus capitis; Staphylococcal Infections; Anti-Bacterial Agents; Sepsis; Intensive Care Units, Neonatal
PubMed: 37791541
DOI: 10.1099/mgen.0.001106 -
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 -
Antibiotics (Basel, Switzerland) Feb 2024has been recognized as a relevant opportunistic pathogen, particularly its persistence in neonatal ICUs around the world. Therefore, the aim of this study was to...
has been recognized as a relevant opportunistic pathogen, particularly its persistence in neonatal ICUs around the world. Therefore, the aim of this study was to describe the epidemiological profile of clinical isolates of and to characterize the factors involved in the persistence and pathogenesis of these strains isolated from blood cultures collected in a hospital in the interior of the state of São Paulo, Brazil. A total of 141 strains were submitted to detection of the gene and S typing by multiplex PCR. Genes involved in biofilm production and genes encoding enterotoxins and hemolysins were detected by conventional PCR. Biofilm formation was evaluated by the polystyrene plate adherence test and phenotypic resistance was investigated by the disk diffusion method. Finally, pulsed-field gel electrophoresis (PFGE) was used to analyze the clonal relationship between isolates. The gene was detected in 99 (70.2%) isolates, with this percentage reaching 100% in the neonatal ICU. SCC type III was the most prevalent type, detected in 31 (31.3%) isolates and co-occurrence of SCC was also observed. In vitro biofilm formation was detected in 46 (32.6%) isolates but was not correlated with the presence of the operon genes. Furthermore, biofilm production in ICU isolates was favored by hyperosmotic conditions, which are common in ICUs because of the frequent parenteral nutrition. Analysis of the clonal relationship between the isolates investigated in the present study confirms a homogeneous profile of and the persistence of clones that are prevalent in the neonatal ICU and disseminated across the hospital. This study highlights the adaptation of isolates to specific hospital environments and their high clonality.
PubMed: 38391533
DOI: 10.3390/antibiotics13020147 -
Foods (Basel, Switzerland) Oct 2022Biofilms are highly resistant to external forces, especially chemicals. Hence, alternative control strategies, like antimicrobial substances, are forced. Antimicrobial...
Biofilms are highly resistant to external forces, especially chemicals. Hence, alternative control strategies, like antimicrobial substances, are forced. Antimicrobial surfaces can inhibit and reduce microbial adhesion to surfaces, preventing biofilm formation. Thus, this research aimed to investigate the bacterial attachment and biofilm formation on different sealants and stainless steel (SS) surfaces with or without antimicrobials on two Gram-positive biofilm forming bacterial strains. Antimicrobial surfaces were either incorporated or coated with anti-microbial, -fungal or/and bactericidal agents. Attachment (after 3 h) and early-stage biofilm formation (after 48 h) of () and () onto different surfaces were assessed using the plate count method. In general, bacterial adhesion on sealants was lower compared to adhesion on SS, for surfaces with and without antimicrobials. Antimicrobial coatings on SS surfaces played a role in reducing early-stage biofilm formation for , however, no effects were observed for . adhesion and biofilm formation were reduced by 8% and 25%, respectively, on SS coated with an antimicrobial substance (SS_4_M), compared to the same surface without the antimicrobial coating (SS_4_control). Incorporation of both antifungicidal and bactericidal agents (S_5_FB) significantly reduced ( ≤ 0.05) early-stage biofilm formation of compared to the other sealants incoportating either solely antifungal agents (S_2_F) or no active compound (S_control). Furthermore, the thickness of the coating layer correlated weakly with the antimicrobial effect. Hence, equipment manufacturers and food producers should carefully select antimicrobial surfaces as their effects on bacterial adhesion and early-stage biofilm formation depend on the active agent and bacterial species.
PubMed: 36230171
DOI: 10.3390/foods11193096 -
Antibiotics (Basel, Switzerland) Oct 2022Neonatal infection is a significant cause of mortality and morbidity in infants. The global incidence of multi-drug resistance continues to rise among neonatal...
Neonatal infection is a significant cause of mortality and morbidity in infants. The global incidence of multi-drug resistance continues to rise among neonatal pathogens, indicating a need for alternative treatment strategies. Nisin is an antimicrobial peptide that exhibits broad-spectrum activity against a wide variety of clinical pathogens and can be used in combination with antibiotics to improve their effectiveness. This study examined the activity of nisin and bioengineered derivatives against multi-drug resistant and isolates and investigated the potential synergy between nisin peptides and selected antibiotics. Whole genome sequence analysis of the strains revealed the presence of multi-drug resistant determinants, e.g., macrolide, tetracycline, β-lactam, aminoglycoside, while the strains all possessed both and FP genes and the strains were found to encode the gene alone. Deferred antagonism assays demonstrated that nisin PV had improved antimicrobial activity against all strains tested ( = 10). The enhanced specific activity of this peptide was confirmed using minimum inhibitory concentrations (MIC) (0-4-fold lower MIC for nisin PV) and broth-based survival assays. Combinations of nisin peptides with antibiotics were assessed for enhanced antimicrobial activity using growth and time-kill assays and revealed a more effective nisin PV/ampicillin combination against one strain while a nisin A/erythromycin combination displayed a synergistic effect against one strain. The findings of this study suggest that nisin derivatives alone and in combination with antibiotics have potential as alternative antimicrobial strategies to target neonatal pathogens.
PubMed: 36358171
DOI: 10.3390/antibiotics11111516 -
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 -
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