- Institute of Medical Microbiology
University Hospital Münster
http://klinikum.uni-muenster.de/index.php?id=1887
Karsten Becker
University of Münster, Institute of Medical Microbiology, Faculty Member
Descriptive values were determined for eight antifungal agents within the course of a multi-centre study encompassing 1062 German and Austrian clinical yeast isolates. Candida albicans (54%) was the predominant species isolated followed... more
Descriptive values were determined for eight antifungal agents within the course of a multi-centre study encompassing 1062 German and Austrian clinical yeast isolates. Candida albicans (54%) was the predominant species isolated followed by Candida glabrata (22%), Candida parapsilosis (6%), Candida tropicalis (5.7%), Candida krusei (4.3%), as well as eleven further candidal and four non-Candida yeast species. While 519 (48.9%) isolates were tested susceptible to all antifungals tested, no isolate was found to exhibit complete cross resistance. For C. albicans, the proportions of susceptible isolates were 93.2% (amphotericin B), 95.6% (flucytosine), 84.3% (fluconazole), 83.8% (posaconazole), 91.8% (voriconazole), 96.5% (anidulafungin), 96.2% (caspofungin) and 97.6% (micafungin). Patterns of complete parallel resistances were observed within azoles (8.8%) and echinocandins (1.7%). While a decreased susceptibility was found infrequently for echinocandins and flucytosine, it was more com...
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Similar to,confers resistance against beta-lactams, leading to the phenotype of methicillin-resistant(MRSA). However,-harboring MRSA strains pose special difficulties in their detection. The aim of this study was to assess and compare... more
Similar to,confers resistance against beta-lactams, leading to the phenotype of methicillin-resistant(MRSA). However,-harboring MRSA strains pose special difficulties in their detection. The aim of this study was to assess and compare different phenotypic systems for screening, identification, and susceptibility testing of-positive MRSA isolates. A well-characterized collection of-positiveisolates (= 111) was used for evaluation. Routinely used approaches were studied to determine their suitability to correctly identify-harboring MRSA, including three (semi)automated antimicrobial susceptibility testing (AST) systems and five selective chromogenic agar plates. Additionally, a cefoxitin disk diffusion test and an oxacillin broth microdilution assay were examined. All-harboring MRSA isolates were able to grow on all chromogenic MRSA screening plates tested. Detection of these isolates in AST systems based on cefoxitin and/or oxacillin testing yielded overall positive agreements with t...
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Nucleic acid amplification techniques (NATs), such as PCR, are highly sensitive and specific methods that have become valuable supplements to culture and serology in the diagnosis of infectious disorders. However, especially when using... more
Nucleic acid amplification techniques (NATs), such as PCR, are highly sensitive and specific methods that have become valuable supplements to culture and serology in the diagnosis of infectious disorders. However, especially when using formalin-fixed and paraffin-embedded tissue, these techniques are associated with both false-negative and false-positive results, a pitfall that is frequently misjudged. Representatives of the German Society of Hygiene and Microbiology (DGHM) and the German Society of Dermatology (DDG) therefore set out to develop a consensus - in the form of a review article - on the appropriate indications for NATs using paraffin-embedded tissue, its contraindications, and the key points to be considered in the pre- and post-analytical phase. Given that fresh, naive tissue is preferably to be used in the workup of a suspected infection, PCR analysis on paraffin sections represents an exception. The latter may be considered if an infection is suspected at a later poi...
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Nukleinsäure-Amplifikations-Techniken (NAT), wie die PCR, sind hochsensitiv sowie selektiv und stellen in der mikrobiologischen Diagnostik wertvolle Ergänzungen zur kulturellen Anzucht und Serologie dar. Sie bergen aber gerade bei... more
Nukleinsäure-Amplifikations-Techniken (NAT), wie die PCR, sind hochsensitiv sowie selektiv und stellen in der mikrobiologischen Diagnostik wertvolle Ergänzungen zur kulturellen Anzucht und Serologie dar. Sie bergen aber gerade bei formalinfixiertem und in Paraffin eingebettetem Gewebe ein Risiko für sowohl falsch negative als auch falsch positive Resultate, welches nicht immer richtig eingeschätzt wird. Daher haben Vertreter der Deutschen Gesellschaft für Hygiene und Mikrobiologie (DGHM) und der Deutschen Dermatologischen Gesellschaft (DDG) einen Konsensus in Form einer Übersichtsarbeit erarbeitet, wann eine NAT am Paraffinschnitt angezeigt und sinnvoll ist und welche Punkte dabei in der Präanalytik und Befundinterpretation beachtet werden müssen. Da bei Verdacht auf eine Infektion grundsätzlich Nativgewebe genutzt werden soll, ist die PCR am Paraffinschnitt ein Sonderfall, wenn beispielsweise bei erst nachträglichaufgekommenem Verdacht auf eine Infektion kein Nativmaterial zur Verf...
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Patients undergoing intensive chemotherapy for acute myeloid leukemia are at high risk for bacterial infections during therapy-related neutropenia. However, the use of specific antibiotic regimens for prophylaxis in afebrile neutropenic... more
Patients undergoing intensive chemotherapy for acute myeloid leukemia are at high risk for bacterial infections during therapy-related neutropenia. However, the use of specific antibiotic regimens for prophylaxis in afebrile neutropenic acute myeloid leukemia patients is controversial. This was a retrospective evaluation of 172 acute myeloid leukemia patients who received 322 courses of myelosuppressive chemotherapy and had an expected duration of neutropenia of >7 days. The patients were allocated to antibiotic prophylaxis groups and treated with colistin or ciprofloxacin through 2 different hematological services at our hospital as available. The infection rate was reduced from 88.6% to 74.2% through antibiotic prophylaxis (vs. without prophylaxis, p=0.04). A comparison of both antibiotic drugs revealed a trend towards fewer infections associated with ciprofloxacin prophylaxis (69.2% vs. 79.5% in the colistin group, p=0.07), as determined by univariate analysis. This result was...
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Adolescent, Medicine, Humans, Internal Medicine, Female, and 15 moreMale, Antibiotic Prophylaxis, Mucositis, Aged, Middle Aged, Adult, Colistin, Retrospective Studies, Bacterial infections, Ciprofloxacin, Central Venous Catheters, Antineoplastic Agents, Cohort Studies, neutropenia, and Cardiovascular medicine and haematology
Results of disk diffusion antimicrobial susceptibility testing depend on individual visual reading of inhibition zone diameters. Therefore, automated reading using camera systems might represent a useful tool for standardization. In this... more
Results of disk diffusion antimicrobial susceptibility testing depend on individual visual reading of inhibition zone diameters. Therefore, automated reading using camera systems might represent a useful tool for standardization. In this study, the ADAGIO automated system (Bio-Rad) was evaluated for reading disk diffusion tests of fastidious bacteria. 144 clinical isolates (68 β-haemolytic streptococci, 28 Streptococcus pneumoniae, 18 viridans group streptococci, 13 Haemophilus influenzae, 7 Moraxella catarrhalis, and 10 Campylobacter jejuni) were tested on Mueller-Hinton agar supplemented with 5% defibrinated horse blood and 20 mg/L β-NAD (MH-F, Oxoid) according to EUCAST. Plates were read manually with a ruler and automatically using the ADAGIO system. Inhibition zone diameters, indicated by the automated system, were visually controlled and adjusted, if necessary. Among 1548 isolate-antibiotic combinations, comparison of automated vs. manual reading yielded categorical agreement ...
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Livestock is often colonized with ESBL-producing Enterobacteriaceae (ESBL-E) and Staphylococcus aureus. There is a risk that flies spread antimicrobial resistant bacteria from livestock to humans. Here, we screened flies from urban and... more
Livestock is often colonized with ESBL-producing Enterobacteriaceae (ESBL-E) and Staphylococcus aureus. There is a risk that flies spread antimicrobial resistant bacteria from livestock to humans. Here, we screened flies from urban and rural areas near the city of Münster, Germany, for the presence of ESBL-E and S. aureus and compared molecular characteristics of these isolates with those isolated from humans in the same region. In total, 1346 single flies were grinded and cultured overnight in BHI-broth. The broth was cultured on Columbia blood agar and selective media for the detection of S. aureus and ESBL-E. Human isolates from routine diagnostics at the University Hospital Münster were used for comparison. Antimicrobial susceptibility, phylogroups (Escherichia coli), spa types/multilocus sequence types (S. aureus) and selected antimicrobial resistance genes were determined for each isolate. GPS data of the sampling sites were used to map flies carrying ESBL-E and S. aureus. Ove...
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Contamination of water is a major burden in the public health setting of developing countries. We therefore assessed the quality of water samples in Gabon in 2013. The main findings were a contamination rate with coliforms of 13.5% and... more
Contamination of water is a major burden in the public health setting of developing countries. We therefore assessed the quality of water samples in Gabon in 2013. The main findings were a contamination rate with coliforms of 13.5% and the detection of a possible environmental reservoir for extended spectrum beta-lactamase-producing bacteria.
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SeptiFast multiplex PCR assay was evaluated for detecting true bloodstream infections (BSIs) with coagulase-negative staphylococci (CoNS) in neutropenic hematological patients. Sensitivity for samples representing true CoNS-BSIs was 23.3%... more
SeptiFast multiplex PCR assay was evaluated for detecting true bloodstream infections (BSIs) with coagulase-negative staphylococci (CoNS) in neutropenic hematological patients. Sensitivity for samples representing true CoNS-BSIs was 23.3% with an integrated cutoff and increased to 83.3% if the cutoff was neglected. Hence, the cutoff may prohibit timely targeted antimicrobial therapy.
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Microbiology, Medical Microbiology, Biology, Medicine, Humans, and 13 moreSepsis, Antimicrobial, Clinical Sciences, Adult, Staphylococcus, Febrile Neutropenia, Coagulase, Molecular Diagnostic Techniques, Cons, Sensitivity and Specificity, neutropenia, multiplex polymerase chain reaction, and Hematologic neoplasms
HY-133 is a recombinant bacteriophage endolysin with bactericidal activity against Staphylococcus aureus. Here, HY-133 showed in vitro activity against major African methicillin-susceptible and methicillin-resistant S. aureus lineages,... more
HY-133 is a recombinant bacteriophage endolysin with bactericidal activity against Staphylococcus aureus. Here, HY-133 showed in vitro activity against major African methicillin-susceptible and methicillin-resistant S. aureus lineages, ceftaroline/ceftobiprole- and borderline oxacillin-resistant isolates. HY-133 was also active against Staphylococcus schweitzeri, a recently described species of S. aureus complex. The activity of HY-133 on the tested isolates (MIC50 0.25 μg/ml, MIC90 0.5 μg/ml, range 0.125-0.5 μg/ml) was independent of the species and strain background or antibiotic resistance.
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Microbiology, Africa, Medical Microbiology, Biology, Medicine, and 14 moreIn Vitro, Humans, Staphylococcus aureus, Cephalosporins, Antibiotics, Recombinant DNA, Anti-Bacterial Agents, Methicillin Resistance, Staphylococcus, Microbial Sensitivity Tests, Recombinant Proteins, Bacteriophage, beta-Lactam Resistance, and Pharmacology and pharmaceutical sciences
An advanced methicillin-resistant Staphylococcus aureus (MRSA) detection PCR approach targeting SCC mec-orfX along with mecA and mecC was evaluated for S. aureus and coagulase-negative staphylococci. The possession of mecA and/or mecC was... more
An advanced methicillin-resistant Staphylococcus aureus (MRSA) detection PCR approach targeting SCC mec-orfX along with mecA and mecC was evaluated for S. aureus and coagulase-negative staphylococci. The possession of mecA and/or mecC was correctly confirmed in all cases. All methicillin-susceptible S. aureus strains ( n = 98; including staphylococcal cassette chromosome mec element [SCC mec ] remnants) and 98.1% of the MRSA strains ( n = 160, including 10 mecC -positive MRSA) were accurately categorized.
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The ability to attach to host ligands is a well-established pathogenic factor in invasive Staphylococcus aureus disease. In addition to the family of adhesive proteins bound to the cell wall via the sortase A (srtA) mechanism, secreted... more
The ability to attach to host ligands is a well-established pathogenic factor in invasive Staphylococcus aureus disease. In addition to the family of adhesive proteins bound to the cell wall via the sortase A (srtA) mechanism, secreted proteins such as the fibrinogen-binding protein Efb, the extracellular adhesion protein Eap, or coagulase have been found to interact with various extracellular host molecules. Here we describe a novel protein, the extracellular matrix protein-binding protein (Emp) initially identified in Western ligand blots as a 40-kDa protein due to its broad-spectrum recognition of fibronectin, fibrinogen, collagen, and vitronectin. Emp is expressed in the stationary growth phase and is closely associated with the cell surface and yet is extractable by sodium dodecyl sulfate. The conferring gene emp (1,023 nucleotides) encodes a signal peptide of 26 amino acids and a mature protein of a calculated molecular mass of 35.5 kDa. Using PCR, emp was demonstrated in all ...
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Systemische Antibiotika werden, wenn möglich, gezielt, ansonsten kalkuliert zur Bekämpfung von bakteriellen Infektionserkrankungen eingesetzt. Die zu behandelnden Erreger ergeben sich aus dem klinischen Bild oder aus der mikrobiologischen... more
Systemische Antibiotika werden, wenn möglich, gezielt, ansonsten kalkuliert zur Bekämpfung von bakteriellen Infektionserkrankungen eingesetzt. Die zu behandelnden Erreger ergeben sich aus dem klinischen Bild oder aus der mikrobiologischen Identifizierung – hierfür muss das Material korrekt gewonnen werden. Wegen der demografischen Entwicklung mit altersbedingter Multimorbidität und Polypharmazie sind für die Auswahl des Antibiotikums aber nicht nur das Erregerspektrum und die Gewebepenetration, sondern auch die jeweiligen Risiken für unerwünschte Nebenwirkungen und Arzneimittelinteraktionen wichtig.In dieser Übersichtsarbeit werden für die verschiedenen Antibiotikagruppen Wirkungsweise, mögliche Resistenzmechanismen, Pharmakokinetik, unerwünschte Nebenwirkungen, Arzneimittelinteraktionen und Indikationen in der Dermatologie aufgeführt.Für viele bakterielle Haut- und Weichgewebeinfektionen stellen β-Lactam-Antibiotika die Mittel der ersten Wahl dar. Sie sind häufig ausreichend wirksa...
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Briefly incubated agar cultures from positive blood cultures were used for antimicrobial susceptibility testing (AST) by Vitek 2. The cultivation time until inoculation was 3.8 h for Gram-positive cocci and 2.4 h for Gram-negative rods.... more
Briefly incubated agar cultures from positive blood cultures were used for antimicrobial susceptibility testing (AST) by Vitek 2. The cultivation time until inoculation was 3.8 h for Gram-positive cocci and 2.4 h for Gram-negative rods. The error rates were low, providing early and reliable AST without additional time or cost expenditure.
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Microbiology, Biology, Medicine, Clinical Microbiology, Biological Sciences, and 15 moreHumans, Blood, Antimicrobial, Gram Positive Bacteria, Gram-negative bacteria, Anti-Bacterial Agents, Time Factors, Inoculation, Bacteremia, Microbial Sensitivity Tests, Gram, Agar, Blood Culture, Gram-positive Cocci, and Medical and Health Sciences
In staphylococci, methicillin resistance is mediated by mecA-encoded penicillin-binding protein 2a (PBP2a), which has a low affinity for beta-lactams. Recently, a novel PBP2a homolog was described as being encoded by mecC, which shares... more
In staphylococci, methicillin resistance is mediated by mecA-encoded penicillin-binding protein 2a (PBP2a), which has a low affinity for beta-lactams. Recently, a novel PBP2a homolog was described as being encoded by mecC, which shares only 70% similarity to mecA. To prove that mecC is the genetic determinant that confers methicillin resistance in Staphylococcus aureus, a mecC knockout strain was generated. The S. aureus ΔmecC strain showed considerably reduced oxacillin and cefoxitin MICs (0.25 and 4 μg/ml, respectively) compared to those of the corresponding wild-type methicillin-resistant S. aureus (MRSA) strain (8 and 16 μg/ml, respectively). Complementing the mutant in trans with wild-type mecC restored the resistance to oxacillin and cefoxitin. By expressing mecC and mecA in different S. aureus clonal lineages, we found that mecC mediates resistance irrespective of the genetic strain background, yielding oxacillin and cefoxitin MIC values comparable to those with mecA. In addi...
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Microbiology, Medical Microbiology, Biology, Medicine, Staphylococcus aureus, and 8 morePlasmids, Anti-Bacterial Agents, Penicillin-Binding Proteins, Beta Lactams, Microbial Sensitivity Tests, Species Specificity, Methicillin Resistant Staphylococcus Aureus, and Pharmacology and pharmaceutical sciences
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Microbiology, Cystic Fibrosis, Biology, Infectious Diseases, Adolescent, and 15 moreMedicine, Biological Sciences, Prospective studies, Humans, Child, Chronic Disease, Staphylococcus aureus, Infant, Infectious, Prevalence, Anti-Bacterial Agents, Adult, Microbial Sensitivity Tests, Child preschool, and Medical and Health Sciences
Meticillin-resistant Staphylococcus aureus (MRSA) associated with the clonal complex (CC) 398 has emerged among livestock and humans exposed to these animals. MRSA CC398 has so far contributed relatively little to spread of MRSA and the... more
Meticillin-resistant Staphylococcus aureus (MRSA) associated with the clonal complex (CC) 398 has emerged among livestock and humans exposed to these animals. MRSA CC398 has so far contributed relatively little to spread of MRSA and the burden of disease in the healthcare setting. This study aimed to assess whether demographic and clinical differences in patients colonized with MRSA CC398 and those carrying other MRSA clones contribute to the observed differences in transmission and infection rates. Age, sex, length of stay (LOS), diagnoses and medical procedures were assessed in all patients with MRSA admitted to a university hospital in 2008 and 2009. S. aureus protein A gene (spa) typing was performed on the first MRSA isolate from each patient. Patients colonized or infected with MRSA that had spa types indicative of CC398 (MRSA CC398) were compared with patients who had other MRSA clones (MRSA non-CC398). Age (53 vs 59 years), mean LOS (8 vs 13 days) and percentage of patients admitted to an intensive care unit (12% vs 17%) differed significantly between MRSA CC398 and MRSA non-CC398 patients, respectively. The mean numbers and types of diagnoses and medical procedures performed for patients in these two groups also differed significantly. The differences in patient characteristics could explain, at least in part, the relatively low rates of transmission and infection associated with MRSA CC398 in the healthcare setting.
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A mecC ( mecA LGA251 )-adapted multiplex PCR-based methicillin-resistant Staphylococcus aureus (MRSA) detection assay was evaluated using an international, spa -typed Staphylococcus aureus collection comprising 51 mecC -positive MRSA, 240... more
A mecC ( mecA LGA251 )-adapted multiplex PCR-based methicillin-resistant Staphylococcus aureus (MRSA) detection assay was evaluated using an international, spa -typed Staphylococcus aureus collection comprising 51 mecC -positive MRSA, 240 mecA -positive MRSA, and 50 mecA - and mecC -negative methicillin-susceptible S. aureus (MSSA) isolates. The assay showed 100% sensitivity and specificity for S. aureus species identification as well as for mecA and mecC detection.
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Microbiology, Biology, Medicine, Clinical Microbiology, Biological Sciences, and 15 moreGermany, Denmark, Identification, Humans, Staphylococcus aureus, Polymerase Chain Reaction, Gene, Rapid Detection, Multiplex, Molecular Diagnostic Techniques, Sensitivity and Specificity, Methicillin Resistant Staphylococcus Aureus, Strains, Medical and Health Sciences, and multiplex polymerase chain reaction
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Microbiology, Medical Microbiology, Medicine, Colonization, Humans, and 15 moreGabon, Female, Male, Infant, Enterobacteriaceae, Antimicrobial chemotherapy, Genotyping, Microbial Sensitivity Tests, Ciprofloxacin, Cross Sectional Studies, Beta Lactamases, meropenem, Child preschool, Carriage, and Cross Infection
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Microbiology, Medical Microbiology, Biology, Medicine, Humans, and 15 moreMutation, Staphylococcus aureus, Antimicrobial chemotherapy, Phenotype, Antibiotics, Anti-Bacterial Agents, Staphylococcus, Microbial Sensitivity Tests, Ciprofloxacin, Culture Media, Hydrogen-Ion Concentration, Fluoroquinolones, Moxifloxacin, Levofloxacin, and Pharmacology and pharmaceutical sciences
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In this study, 425 methicillin-resistant Staphylococcus aureus (MRSA) isolates recovered in the Dutch-German Euregio were investigated for the presence of the arginine catabolic mobile element (ACME). Sequence analysis by whole-genome... more
In this study, 425 methicillin-resistant Staphylococcus aureus (MRSA) isolates recovered in the Dutch-German Euregio were investigated for the presence of the arginine catabolic mobile element (ACME). Sequence analysis by whole-genome sequencing revealed an entirely new organization of the ACME-staphylococcal cassette chromosome mec composite island (SCC mec -CI), with truncated ACME type II located downstream of SCC mec . An identical nucleotide sequence of ACME-SCC mec -CI was found in two distinct MRSA lineages (t064-ST8 and t002-ST5), which has not been reported previously in S. aureus .
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Genetics, Microbiology, Medical Microbiology, Biology, Horizontal Gene Transfer, and 15 moreMedicine, USA, Humans, Staphylococcus aureus, Sequence, Genotype, Methicillin Resistance, Clone, Arginine, Base Sequence, Mobile Genetic Elements, Methicillin Resistant Staphylococcus Aureus, Molecular Sequence Data, Carriage, and Pharmacology and pharmaceutical sciences
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Little data is available on the epidemiology of Staphylococcus aureus in Africa. In the present study we aim at characterizing the population structure of S. aureus in healthy subjects from a rural and a semi-urban area in Lambaréné,... more
Little data is available on the epidemiology of Staphylococcus aureus in Africa. In the present study we aim at characterizing the population structure of S. aureus in healthy subjects from a rural and a semi-urban area in Lambaréné, Gabon as well as in hospital staff and inpatients. In total, 500 subjects were screened for S. aureus colonization of the nares, axillae and inguinal region. Overall, 146 (29%) were positive. We found 46 different spa types. The most frequent spa types were t084 (35%) and the agr II was the most prevalent subtype of the accessory gene regulator (56%, n=82). Five isolates (3%) were methicillin resistant S. aureus (MRSA). Carriage rates of S. aureus in Gabon are comparable to developed countries. MRSA is for the first time described and could pose a significant health threat in this region with limited access to microbiological laboratory facilities and to adequate antimicrobial agents.
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By analyzing the colonization of the anterior nares in cardiothoracic surgery patients on admission, nasal cocolonization by methicillin-susceptible Staphylococcus aureus and methicillin-resistant coagulase-negative staphylococci was... more
By analyzing the colonization of the anterior nares in cardiothoracic surgery patients on admission, nasal cocolonization by methicillin-susceptible Staphylococcus aureus and methicillin-resistant coagulase-negative staphylococci was detected in 8/235 (3.4%) specimens. Consequently, in a low-methicillin-resistant S. aureus (MRSA) setting, a molecular MRSA screening test targeting the mecA gene and an S. aureus -specific gene in parallel and applied directly to clinical specimens would be associated with an unacceptable positive predictive value of about 40%.
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Microbiology, Health Care, Medicine, Clinical Microbiology, Biological Sciences, and 12 moreHumans, Staphylococcus aureus, Methicillin Resistance, Coagulase, Nose, Predictive value of tests, Positive predictive value, Methicillin Resistant Staphylococcus Aureus, Coagulase Negative Staphylococci, False Positive, Medical and Health Sciences, and Methicillin
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Africa, Zoonoses, Adolescent, Chiroptera, Primates, and 22 moreMolecular typing, Humans, Child, Transmission, Female, Animals, Male, Young Adult, Infant, Clinical microbiology and infection control, Clinical Sciences, Newborn Infant, Aged, Middle Aged, Anti-Bacterial Agents, Genotype, Adult, Staphylococcus, Microbial Sensitivity Tests, Virulence Factors, Cross Sectional Studies, and Child preschool
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Salmonella osteomyelitis without predisposing factors is seldom seen and thus difficult to diagnose. We report on a 14-year-old healthy boy with Salmonella osteomyelitis which occurred 2 years after trauma. Radical operative debridement... more
Salmonella osteomyelitis without predisposing factors is seldom seen and thus difficult to diagnose. We report on a 14-year-old healthy boy with Salmonella osteomyelitis which occurred 2 years after trauma. Radical operative debridement is recommended. Intravenous ciprofloxacin has proved to be effective because of good tissue penetration and sensitivity towards Salmonella.
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Small colony variants (SCVs) were first described more than 100 years ago for Staphylococcus aureus and various coagulase-negative staphylococci. Two decades ago, an association between chronic staphylococcal infections and the presence... more
Small colony variants (SCVs) were first described more than 100 years ago for Staphylococcus aureus and various coagulase-negative staphylococci. Two decades ago, an association between chronic staphylococcal infections and the presence of SCVs was observed. Since then, many clinical studies and observations have been published which tie recurrent, persistent staphylococcal infections, including device-associated infections, bone and tissue infections, and airway infections of cystic fibrosis patients, to this special phenotype. By their intracellular lifestyle, SCVs exhibit so-called phenotypic (or functional) resistance beyond the classical resistance mechanisms, and they can often be retrieved from therapy-refractory courses of infection. In this review, the various clinical infections where SCVs can be expected and isolated, diagnostic procedures for optimized species confirmation, and the pathogenesis of SCVs, including defined underlying molecular mechanisms and the phenotype ...
Colonization with livestock-associated Methicillin-resistant Staphylococcusaureus (LA-MRSA) among persons occupationally exposed to pigs, cattle or poultry is very frequent. In Europe, LA-MRSA mostly belong to the clonal lineage CC398.... more
Colonization with livestock-associated Methicillin-resistant Staphylococcusaureus (LA-MRSA) among persons occupationally exposed to pigs, cattle or poultry is very frequent. In Europe, LA-MRSA mostly belong to the clonal lineage CC398. Since colonized persons have an increased risk of developing MRSA infections, defining the burden of work-related infection caused by LA-MRSA CC398 is of interest to exposed personnel, insurance companies and infection control staff. This review summarizes data on the types of occupation-related infections caused by LA-MRSA CC398, the incidence of such infections as well as potential preventive strategies. We identified twelve case reports on infections among livestock-exposed persons. Overall, there is a lack of data describing the incidence of occupation-related infections due to MRSA CC398. Currently, no specific guidance towards the prevention of LA-MRSA CC398 colonization of persons with routine exposure exists. In vitro, MRSA CC398 strains are susceptible (>95%) to mupirocin. Single reports have described effective decolonization of persons carrying LA-MRSA CC398, but long-term success rates are low in case of continuous livestock contact. Overall, the occupational health risk due to LA-MRSA CC398 is not well understood. Currently, prevention of human LA-MRSA CC398 infection is mostly based on the recommendation to perform screening and decolonization therapies prior to elective medical interventions in order to avoid nosocomial infections, but there is no conclusive evidence to perform specific measures aiming to forestall community-acquired infections.
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Staphylococcus epidermidis is an opportunistic pathogen of major clinical interest for its high prevalence in implant-associated infections. However, only little information is available on the phylogeny of its major clonal entities and... more
Staphylococcus epidermidis is an opportunistic pathogen of major clinical interest for its high prevalence in implant-associated infections. However, only little information is available on the phylogeny of its major clonal entities and their virulence and resistance markers. Therefore, purpose of this study was to characterize four clusters identified by automated ribotyping of 70 isolates derived from orthopedic, mostly foreign body-related infections. The ica locus, encoding the polysaccharide intercellular adhesin, the IS256 insertion element as well as the resistance to gentamicin, clindamycin, chloramphenicol, and ciprofloxacin were all traits uniquely observed in two of these clusters. The phylogenetic analysis of the S. epidermidis clusters offered a detailed insight into the clonal origin of exopolysaccharide- producing and multiresistant strains with transposons appearing to be actively involved in genetic exchanges.
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Staphylococcus aureus is the most prevalent pathogen in dermatology causing a broad array of pyogenic, community-acquired (CA) and health care-associated (HA), acute and chronic, superficial and deep skin infections which can progress to... more
Staphylococcus aureus is the most prevalent pathogen in dermatology causing a broad array of pyogenic, community-acquired (CA) and health care-associated (HA), acute and chronic, superficial and deep skin infections which can progress to life-threatening systemic infections. The pathogen causes also toxin-mediated diseases with cutaneous symptoms. Methicillin-resistant S. aureus (MRSA) strains are not sensitive to the beta-lactam antibiotics available in Germany. Even though they cause the same skin infections as methicillin -sensitive strains, they are associated with greater morbidity and mortality because of their resistance to therapy. In addition to HA-MSRA in hospitalized patients with well-known and defined risk factors, there are new CA-MSRA strains which arise in the community or from, animal husbandry sources. These MSRA strains are also a problem in hospitals today. CA-MRSA strains often have special virulence factors, such as Panton Valentine leukocidin), and are often associated with specific often recurrent skin and soft tissue infections (furuncles, abscesses, necrotizing entities).
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Few reports from Africa suggest that resistance pattern, virulence factors and genotypes differ between Staphylococcus aureus from nasal carriage and clinical infection. We therefore compared antimicrobial resistance, selected virulence... more
Few reports from Africa suggest that resistance pattern, virulence factors and genotypes differ between Staphylococcus aureus from nasal carriage and clinical infection. We therefore compared antimicrobial resistance, selected virulence factors and genotypes of S. aureus from nasal carriage and clinical infection in Southwest Nigeria. Non-duplicate S. aureus isolates were obtained from infection (n = 217) and asymptomatic carriers (n = 73) during a cross sectional study in Lagos and Ogun States, Nigeria from 2010-2011. Susceptibility testing was performed using Vitek automated systems. Selected virulence factors were detected by PCR. The population structure was assessed using spa typing. The spa clonal complexes (spa-CC) were deduced using the Based Upon Repeat Pattern algorithm (BURP). Resistance was higher for aminoglycosides in clinical isolates while resistances to quinolones and tetracycline were more prevalent in carrier isolates. The Panton-Valentine leukocidin (PVL) was mor...
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Trimethoprim-sulfamethoxazole (SXT) is a possible alternative for the treatment of community- and hospital-acquired methicillin-resistant Staphylococcus aureus (MRSA) due to the susceptibility of most MRSA strains to the drug. However,... more
Trimethoprim-sulfamethoxazole (SXT) is a possible alternative for the treatment of community- and hospital-acquired methicillin-resistant Staphylococcus aureus (MRSA) due to the susceptibility of most MRSA strains to the drug. However, after long-term treatment with SXT thymidine-dependent (TD) SXT-resistant small-colony variants (SCVs) emerge. In TD-SCVs, mutations of thymidylate synthase (thyA, TS) occur. Until now, it has never been systematically investigated that SXT is triggering the induction and/or selection of TD-SCVs. In our study, we performed induction, reversion and competition experiments in vitro and in vivo using a chronic mouse pneumonia model to determine the impact of SXT on the emergence of TD-SCVs. SCVs were characterized by light and transmission electron-microscopy (TEM) and auxotrophism testing. Short-term exposure of S. aureus to SXT induced the TD-SCV phenotype in S. aureus SH1000, while selection of TD-SCVs with thyA mutations occurred after long-term expo...
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Ceftaroline and ceftobiprole are new cephalosporins, which are active against MRSA by inhibiting PBP2a. Recently, high rates of resistance to ceftaroline were reported from Ghana. The objective of this study was to assess rates of... more
Ceftaroline and ceftobiprole are new cephalosporins, which are active against MRSA by inhibiting PBP2a. Recently, high rates of resistance to ceftaroline were reported from Ghana. The objective of this study was to assess rates of resistance to ceftaroline and ceftobiprole in MRSA from Africa and to describe potential missense mutations of PBP2a. MRSA isolates derived from Staphylococcus aureus colonization (n = 37) and infection (n = 23) and were collected in Côte d'Ivoire (n = 17), DR Congo (n = 6), Gabon (n = 21) and Nigeria (n = 16). The MICs were determined by the broth microdilution method. The mecA gene was sequenced and missense mutations were associated with the corresponding MLST ST. In total, 16.7% (n = 10) and 15% (n = 9) of isolates were resistant to ceftaroline and ceftobiprole, respectively. The corresponding MICs of ceftaroline and ceftobiprole correlated significantly (r = 0.92). Isolates belonging to ST241 harboured a triple mutation of PBP2a (N146K-N204K-G246E...
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Currently, there is an ongoing discussion about the question whether the emergence of multidrug-resistant microorganisms (MDRO) among humans is due to transfer of these bacteria from animals. This review summarizes data on the occurrence... more
Currently, there is an ongoing discussion about the question whether the emergence of multidrug-resistant microorganisms (MDRO) among humans is due to transfer of these bacteria from animals. This review summarizes data on the occurrence of methicillin-resistant Staphylococcus aureus (MRSA) and extended-spectrum beta-lactamase (ESBL) producing enterobacteria in animals and humans, and describes knowledge about transmission pathways. After a scientific literature analysis, relevant articles were identified by screening of titles and abstracts, amended by publications of infection control authorities and the respective reference lists. MDRO are both transmitted in the nosocomial setting and are increasingly detected as sources of infection outside healthcare facilities. Due to new transmission pathways of MDRO an inter-disciplinary approach towards prevention is necessary, involving medical, pharmaceutical and veterinary expertise.
Abstract The chapter begins with the taxonomy, genus descriptions, and natural habitats of Staphylococcus, Micrococcus, and other catalase-positive cocci. Next discussed is the clinical significance of these bacteria, particularly of the... more
Abstract The chapter begins with the taxonomy, genus descriptions, and natural habitats of Staphylococcus, Micrococcus, and other catalase-positive cocci. Next discussed is the clinical significance of these bacteria, particularly of the different Staphylococcus species. ...
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Abstract The chapter begins with the taxonomy, genus descriptions, and natural habitats of Staphylococcus, Micrococcus, and other catalase-positive cocci. Next discussed is the clinical significance of these bacteria, particularly of the... more
Abstract The chapter begins with the taxonomy, genus descriptions, and natural habitats of Staphylococcus, Micrococcus, and other catalase-positive cocci. Next discussed is the clinical significance of these bacteria, particularly of the different Staphylococcus species. ...