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Clinical Microbiology and Infection :... Sep 2019Progress in contemporary medicine is associated with an increasing number of immunocompromised individuals. In this vulnerable group, the underlying disease together... (Review)
Review
BACKGROUND
Progress in contemporary medicine is associated with an increasing number of immunocompromised individuals. In this vulnerable group, the underlying disease together with long-term hospitalization and the use of medical devices facilitate infections by opportunistic pathogens, of which coagulase-negative staphylococci (CoNS) represent a prime example.
OBJECTIVES
The diversity of CoNS with species- and strain-specific differences concerning virulence and clinical impact is highlighted. A focus is on the ability of CoNS to generate biofilms on biotic and abiotic surfaces, which enables skin and mucosa colonization as well as establishment of CoNS on indwelling foreign bodies.
SOURCES
Literature about the virulence of CoNS listed in PubMed was reviewed.
CONTENT
Most catheter-related and prosthetic joint infections as well as most other device-related infections are caused by CoNS, specifically by Staphylococcus epidermidis and Staphylococcus haemolyticus. A common theme of CoNS infections is a high antibiotic resistance rate, which often limits treatment options and contributes to the significant health and economic burden imposed by CoNS.
IMPLICATIONS
Breaching the skin barrier along with the insertion of medical devices offers CoNS opportunities to gain access to host tissues and to sustain there by forming biofilms on foreign body surfaces. Biofilms represent the perfect niche to protect CoNS from both the host immune response and the action of antibiotics. Their particular lifestyle, combined with conditions that facilitate host colonization and infection, has led to the growing impact of CoNS as pathogens. Moreover, CoNS may serve as hidden reservoirs for antibiotic resistance and virulence traits.
Topics: Animals; Anti-Bacterial Agents; Biofilms; Catheter-Related Infections; Coagulase; Drug Resistance, Multiple, Bacterial; Humans; Staphylococcal Infections; Staphylococcus; Virulence
PubMed: 30502487
DOI: 10.1016/j.cmi.2018.11.012 -
Microorganisms May 2022) constitutes the main part of the human skin microbiota. It is widespread in hospitals and among medical staff, resulting in being an emerging microbe causing... (Review)
Review
) constitutes the main part of the human skin microbiota. It is widespread in hospitals and among medical staff, resulting in being an emerging microbe causing nosocomial infections. , especially strains that cause nosocomial infections, are more resistant to antibiotics than other coagulase-negative Staphylococci. There is clear evidence that the resistance genes can be acquired by other Staphylococcus species through . Severe infections are recorded with such as meningitis, endocarditis, prosthetic joint infections, bacteremia, septicemia, peritonitis, and otitis, especially in immunocompromised patients. In addition, species were detected in dogs, breed kennels, and food animals. The main feature of pathogenic isolates is the formation of a biofilm which is involved in catheter-associated infections and other nosocomial infections. Besides the biofilm formation, secretes other factors for bacterial adherence and invasion such as enterotoxins, hemolysins, and fibronectin-binding proteins. In this review, we give updates on the clinical infections associated with , highlighting the antibiotic resistance patterns of these isolates, and the virulence factors associated with the disease development.
PubMed: 35744647
DOI: 10.3390/microorganisms10061130 -
Microbiology Spectrum Aug 2022Infections caused by antibiotic-resistant are a global concern. This is true in the Middle East, where increasingly resistant Staphylococcus aureus and Staphylococcus...
Infections caused by antibiotic-resistant are a global concern. This is true in the Middle East, where increasingly resistant Staphylococcus aureus and Staphylococcus haemolyticus strains have been detected. While extensive surveys have revealed the prevalence of infections caused by antibiotic-resistant staphylococci in Europe, Asia, and North America, the population structure of antibiotic-resistant staphylococci recovered from patients and clinical settings in Egypt remains uncharacterized. We performed whole-genome sequencing of 56 S. aureus and 10 S. haemolyticus isolates from Alexandria Main University Hospital; 46 of the S. aureus genomes and all 10 of the genomes carry , which confers methicillin resistance. Supplemented with additional publicly available genomes from the other parts of the Middle East (34 S. aureus and 6 ), we present the largest genomic study to date of staphylococcal isolates from the Middle East. These genomes include 20 S. aureus multilocus sequence types (MLST), including 3 new ones. They also include 9 MLSTs, including 1 new one. Phylogenomic analyses of each species' core genome largely mirrored those of the MLSTs, irrespective of geographical origin. The hospital-acquired t037/ST239-SCC III/MLST CC8 clone represented the largest clade, comprising 22% of the S. aureus isolates. Like S. aureus genome surveys of other regions, these isolates from the Middle East have an open pangenome, a strong indicator of gene exchange of virulence factors and antibiotic resistance genes with other reservoirs. Our genome analyses will inform antibiotic stewardship and infection control plans in the Middle East. Staphylococci are understudied despite their prevalence within the Middle East. Methicillin-resistant Staphylococcus aureus (MRSA) is endemic to hospitals in Egypt, as are other antibiotic-resistant strains of S. aureus and . To provide insight into the strains circulating in Egypt, we performed whole-genome sequencing of 56 S. aureus and 10 isolates from Alexandria Main University Hospital. Through analysis of these genomes, as well as all available S. aureus and genomes from the Middle East ( = 40), we were able to produce a picture of the diversity in this region more complete than those afforded by traditional molecular typing strategies. For example, we identified 4 new MLSTs. Most strains harbored genes associated with multidrug resistance, toxin production, biofilm formation, and immune evasion. These data provide invaluable insight for future antibiotic stewardship and infection control within the Middle East.
Topics: Anti-Bacterial Agents; Egypt; Humans; Methicillin-Resistant Staphylococcus aureus; Microbial Sensitivity Tests; Multilocus Sequence Typing; Staphylococcal Infections; Staphylococcus; Staphylococcus aureus; Staphylococcus haemolyticus
PubMed: 35727037
DOI: 10.1128/spectrum.02413-21 -
Animals : An Open Access Journal From... Nov 2023This work aimed to determine the presence of bacterial pathogens in fish with a clinical picture suggestive of infectious disease in Nile tilapia reared in Chiapas,...
This work aimed to determine the presence of bacterial pathogens in fish with a clinical picture suggestive of infectious disease in Nile tilapia reared in Chiapas, Mexico. Blood and viscera samples were taken from healthy and diseased animals from commercial farms. Clinical and pathological examinations of each individual were performed and samples were collected for bacteriological studies. The bacterial isolates were identified and characterized by culture, biochemical tests, antibiogram, challenge tests and 16S rRNA sequencing. and were isolated from various diseased organisms. The clinical picture caused by was characterized by appetite disorders, neurological signs, nodulation or ulceration in different areas and congestion or enlargement of internal organs. Providenciosis in juvenile specimens caused a characteristic picture of hemorrhagic septicemia. Challenge tests performed in healthy organisms revealed that both infections caused higher mortality rates in fish ( < 0.05) compared with non-infected specimens, with 100% survival. There was 100% mortality for animals infected with after three days post infection and 45% for those infected with . The isolation and identification of two pathogens involved in an infection process were achieved and cataloged as potential causal agents of disease outbreaks in tilapia farming in Mexico. This is the first report of possible bacterial infection caused by and in tilapia farms, which are two uncommon but potentially emerging pathogens for the species.
PubMed: 38067066
DOI: 10.3390/ani13233715 -
Analytica Chimica Acta Sep 2023Staphylococcus haemolyticus (S. haemolyticus), which is highly prevent in the hospital environment, is an etiological factor for nosocomial infections. Point-of-care...
Staphylococcus haemolyticus (S. haemolyticus), which is highly prevent in the hospital environment, is an etiological factor for nosocomial infections. Point-of-care rapid testing (POCT) of S. haemolyticus is not possible with the currently used detection methods. Recombinase polymerase amplification (RPA) is a novel isothermal amplification technology with high sensitivity and specificity. The combination of RPA and lateral flow strips (LFS) can achieve rapid pathogen detection, enabling POCT. This study developed an RPA-LFS methodology using a specific probe/primer pair to identify S. haemolyticus. A basic RPA reaction was performed to screen the specific primer from 6 primer pairs targeting mvaA gene. The optimal primer pair was selected based on agarose gel electrophoresis, and the probe was designed. To eliminate false-positive results caused by the byproducts, base mismatches were introduced in the primer/probe pair. The improved primer/probe pair could specifically identify the target sequence. To explore the optimal reaction conditions, the effects of reaction temperature and duration of the RPA-LFS method were systematically investigated. The improved system enabled optimal amplification at 37 °C for 8 min, and the results were visualized within 1 min. The S. haemolyticus detection sensitivity of the RPA-LFS method, whose performance was unaffected by contamination with other genomes, was 0.147 CFU/reaction. Furthermore, we analyzed 95 random clinical samples with RPA-LFS, quantitative polymerase chain reaction (qPCR), and traditional bacterial-culture assays and found that the RPA-LFS had 100% and 98.73% compliance rates with the qPCR and traditional culture method, respectively, which confirms its clinical applicability. In this study, we designed an improved RPA-LFS assay based on the specific probe/primer pair for the detection of S. haemolyticus via rapid POCT, free from the limitations of the precision instruments, helping to make diagnoses and treatment decisions as soon as possible.
Topics: Recombinases; Nucleic Acid Amplification Techniques; Staphylococcus haemolyticus; Sensitivity and Specificity
PubMed: 37423664
DOI: 10.1016/j.aca.2023.341534 -
Frontiers in Cellular and Infection... 2023Non-aureus (NAS) species are currently the most commonly identified microbial agents causing sub-clinical infections of the udder and are also deemed as opportunistic...
INTRODUCTION
Non-aureus (NAS) species are currently the most commonly identified microbial agents causing sub-clinical infections of the udder and are also deemed as opportunistic pathogens of clinical mastitis in dairy cattle. More than 10 NAS species have been identified and studied but little is known about in accordance with dairy mastitis. The present study focused on the molecular epidemiology and genotypic characterization of isolated from dairy cattle milk in Northwest, China.
METHODS
In this study, a total of 356 milk samples were collected from large dairy farms in three provinces in Northwest, China. The bacterial isolation and presumptive identification were done by microbiological and biochemical methods following the molecular confirmation by 16S rRNA gene sequencing. The antimicrobial susceptibility testing (AST) was done by Kirby-Bauer disk diffusion assay and antibiotic-resistance genes (ARGs) were identified by PCR. The phylogenetic grouping and sequence typing was done by Pulsed Field Gel Electrophoresis (PFGE) and Multi-Locus Sequence Typing (MLST) respectively.
RESULTS
In total, 39/356 (11.0%) were identified as positive for . The overall prevalence of other species was noted to be 39.6% (141/356), while the species distribution was as follows: 14.9%, 10.4%, 7.6%, 4.2%, 1.4%, and 1.1%. The antimicrobial susceptibility of 39 strains exhibited higher resistance to erythromycin (92.3%) followed by trimethoprim-sulfamethoxazole (51.3%), ciprofloxacin (43.6%), florfenicol (30.8%), cefoxitin (28.2%), and gentamicin (23.1%). All of the strains were susceptible to tetracycline, vancomycin, and linezolid. The overall percentage of multi-drug resistant (MDR) strains was noted to be 46.15% (18/39). Among ARGs, was identified as predominant (82.05%), followed by (33.33%), (30.77%), (30.77%), (28.21%), (23.08%), (12.82%), (12.82%), D (10.26%), (10.26%), A (7.69%), and G (5.13%). The PFGE categorized 39 strains into A-H phylogenetic groups while the MLST categorized strains into eight STs with ST8 being the most predominant while other STs identified were ST3, ST11, ST22, ST32, ST19, ST16, and ST7.
CONCLUSION
These findings provided new insights into our understanding of the epidemiology and genetic characteristics of in dairy farms to inform interventions limiting the spread of AMR in dairy production.
Topics: Female; Cattle; Animals; Staphylococcus haemolyticus; Methicillin-Resistant Staphylococcus aureus; Staphylococcus aureus; Staphylococcal Infections; Multilocus Sequence Typing; Molecular Epidemiology; Milk; Phylogeny; RNA, Ribosomal, 16S; Mastitis, Bovine; Staphylococcus; Anti-Bacterial Agents; Microbial Sensitivity Tests
PubMed: 37265496
DOI: 10.3389/fcimb.2023.1183390 -
Frontiers in Microbiology 2022Antibiotics play a vital role in saving millions of lives from fatal infections; however, the inappropriate use of antibiotics has led to the emergence and propagation... (Review)
Review
Antibiotics play a vital role in saving millions of lives from fatal infections; however, the inappropriate use of antibiotics has led to the emergence and propagation of drug resistance worldwide. Multidrug-resistant bacteria represent a significant challenge to treating infections due to the limitation of available antibiotics, necessitating the investigation of alternative treatments for combating these superbugs. Under such circumstances, antimicrobial peptides (AMPs), including human-derived AMPs and bacteria-derived AMPs (so-called bacteriocins), are considered potential therapeutic drugs owing to their high efficacy against infectious bacteria and the poor ability of these microorganisms to develop resistance to them. Several staphylococcal species including , , , and are commensal bacteria and known to cause many opportunistic infectious diseases. Methicillin-resistant , especially methicillin-resistant (MRSA), are of particular concern among the critical multidrug-resistant infectious Gram-positive pathogens. Within the past decade, studies have reported promising AMPs that are effective against MRSA and other methicillin-resistant . This review discusses the sources and mechanisms of AMPs against staphylococcal species, as well as their potential to become chemotherapies for clinical infections caused by multidrug-resistant staphylococci.
PubMed: 35756032
DOI: 10.3389/fmicb.2022.930629 -
Toxins Sep 2015Although opportunistic pathogens, coagulase-negative staphylococci (CoNS), including Staphylococcus epidermidis and Staphylococcus haemolyticus, have long been regarded...
Although opportunistic pathogens, coagulase-negative staphylococci (CoNS), including Staphylococcus epidermidis and Staphylococcus haemolyticus, have long been regarded as avirulent organisms. The role of toxins in the development of infections caused by CoNS is still controversial. The objective of this study was to characterize the presence of enterotoxin and cytotoxin genes in S. epidermidis and S. haemolyticus isolates obtained from blood cultures. Cytotoxin genes were detected by PCR using novel species-specific primers. Among the 85 S. epidermidis and 84 S. haemolyticus isolates, 95.3% and 79.8%, respectively, carried at least one enterotoxin gene. The most frequent enterotoxin genes were sea (53.3%), seg (64.5%) and sei (67.5%). The seg gene was positively associated with S. epidermidis (p = 0.02), and this species was more toxigenic than S. haemolyticus. The hla/yidD gene was detected in 92.9% of S. epidermidis and the hla gene in 91.7% of S. haemolyticus isolates; hlb was detected in 92.9% of the S. epidermidis isolates and hld in 95.3%. Nosocomial Staphylococcus epidermidis and S. haemolyticus isolates exhibited a high toxigenic potential, mainly producing the non-classical enterotoxins seg and sei. The previously unreported detection of hla/yidD and hlb in S. epidermidis and S. haemolyticus using species-specific primers showed that these hemolysin genes differ between CoNS species and that they are highly frequent in blood culture isolates.
Topics: Cytotoxins; DNA, Bacterial; Enterotoxins; Genes, Bacterial; Humans; Staphylococcus epidermidis; Staphylococcus haemolyticus
PubMed: 26389954
DOI: 10.3390/toxins7093688 -
Infection and Drug Resistance 2023is an opportunistic pathogen that belongs to coagulase-negative (CoNS). Increasing infection and multi-drug resistance cases caused by this strain have been reported...
BACKGROUND
is an opportunistic pathogen that belongs to coagulase-negative (CoNS). Increasing infection and multi-drug resistance cases caused by this strain have been reported and thus it poses a great health threat.
METHODS
The third-generation sequencing technology was performed on a SH-1 isolated from a clinical sample to analyze the drug resistance genes, which included vancomycin resistance related genes. In addition, antimicrobial susceptibility tests, transmission electron microscopy and Triton X-100 stimulated autolysis were conducted to understand its biological characteristics.
RESULTS
The study shows that this clinical isolate is a vancomycin intermediate-resistant strain. Genome comparison also revealed that WalK(N70K) and WalK(R280Q) mutations may contribute to the vancomycin resistant phenotype. Besides, SH-1 exhibit common features of thicker cell wall and decreased autolytic activity.
CONCLUSION
SH-1 with WalKR mutations shows typical characteristics of vancomycin resistant strains. Combining the genome features and biological properties, our findings may provide important information for the understanding of the molecular mechanism of to vancomycin intermediate-resistance.
PubMed: 37313263
DOI: 10.2147/IDR.S411860 -
Microbiology Spectrum Dec 2022Staphylococcus haemolyticus is a major cause of late-onset sepsis in neonates, and endemic clones are often multidrug-resistant. The bacteria can also act as a genetic...
Staphylococcus haemolyticus is a major cause of late-onset sepsis in neonates, and endemic clones are often multidrug-resistant. The bacteria can also act as a genetic reservoir for more pathogenic bacteria. Molecular epidemiology is important in understanding bacterial pathogenicity and preventing infection. To describe the molecular epidemiology of isolated from neonatal blood cultures at a Swedish neonatal intensive care unit (NICU) over 4 decades, including antibiotic resistance genes (ARGs), virulence factors, and comparison to international isolates. Isolates were whole-genome sequenced, and single nucleotide polymorphisms in the core genome were used to map the relatedness. The occurrence of previously described ARGs and virulence genes were investigated. Disc diffusion and gradient tests were used to determine phenotypic resistance. The results revealed a clonal outbreak of at this NICU during the 1990s. Multidrug resistance was present in 28 (82%) of all isolates and concomitant resistance to aminoglycoside and methicillin occurred in 27 (79%). No isolates were vancomycin resistant. Genes encoding ARGs and virulence factors occurred frequently. The isolates in the outbreak were more homogenous in their genotypic and phenotypic patterns. Genotypic and phenotypic resistance combinations were consistent. Pathogenic traits previously described in occurred frequently in the present isolates, perhaps due to the hospital selection pressure resulting in epidemiological success. The clonal outbreak revealed by this study emphasizes the importance of adhering to hygiene procedures in order to prevent future endemic outbreaks. This study investigated the relatedness of Staphylococcus haemolyticus isolated from neonatal blood and revealed a clonal outbreak in the 1990s at a Swedish neonatal intensive care unit. The outbreak clone has earlier been isolated in Japan and Norway. Virulence and antibiotic resistance genes previously associated with clinical were frequently occuring in the present study as well. The majority of the isolates were multidrug-resistant. These traits should be considered important for epidemiological success and are probably caused by the hospital selection pressure. Thus, this study emphasizes the importance of restrictive antibiotic use and following the hygiene procedures, to prevent further antibiotic resistance spread and future endemic outbreaks.
Topics: Infant, Newborn; Humans; Staphylococcus haemolyticus; Staphylococcal Infections; Molecular Epidemiology; Anti-Bacterial Agents; Disease Outbreaks; Virulence Factors; Microbial Sensitivity Tests
PubMed: 36314976
DOI: 10.1128/spectrum.02452-22