Global Epidemiology and Evolutionary History of Staphylococcus aureus ST45.

Staphylococcus aureus ST45 is a major global MRSA lineage with huge strain diversity and a high clinical impact. It is one of the most prevalent carrier lineages but also frequently causes severe invasive disease, such as bacteremia. Little is known about its evolutionary history. In this study, we used whole-genome sequencing to analyze a large collection of 451 diverse ST45 isolates from 6 continents and 26 countries. De novo-assembled genomes were used to understand genomic plasticity and to perform coalescent analyses. The ST45 population contained two distinct sublineages, which correlated with the isolates' geographical origins. One sublineage primarily consisted of European/North American isolates, while the second sublineage primarily consisted of African and Australian isolates. Bayesian analysis predicted ST45 originated in northwestern Europe about 500 years ago. Isolation time, host, and clinical symptoms did not correlate with phylogenetic groups. Our phylogenetic analyses suggest multiple acquisitions of the SCCmec element and key virulence factors throughout the evolution of the ST45 lineage.

Low-level antimicrobial resistance of Enterobacteriaceae isolated from the nares of pig-exposed persons.

Extended-spectrum ß-lactamase (ESBL)-producing Enterobacteriaceae (ESBL-E) have recently emerged in livestock and humans. Therefore, this study assessed the carriage of Enterobacteriaceae in the anterior nares and associated antimicrobial resistance in pig-exposed persons. Nasal swabs were enriched in non-selective broth and then plated on MacConkey and ESBL-selective agars. Species was confirmed by matrix-assisted laser-desorption ionization-time-of-flight mass spectrometry (MALDI-ToF MS). Antimicrobial susceptibility testing was performed according to European Committee on Antimicrobial Susceptibility Testing (EUCAST) guidelines. Of 114 pig-exposed persons tested, Enterobacteriaceae were detected in the nares of 76 (66·7%) participants. The predominant species were Proteus mirabilis (n = 17, 14·9%), Pantoea agglomerans (n = 13, 11·4%), Morganella morganii (n = 9, 7·9%), Citrobacter koseri (n = 9, 7·9%), Klebsiella pneumoniae, Escherichia coli and Proteus vulgaris (each n = 8, 7·0%). ESBL-E were not detected. Of all isolates tested, 3·4% were resistant against ciprofloxacin, 2·3% against gentamicin, 23·9% against trimethoprim-sulfamethoxazole and 44·3% against tigecycline. Despite the high prevalence of ESBL-E in livestock, pig-exposed persons did not carry ESBL-E in their nares. This finding is important, because colonization of the nasal reservoir might cause endogenous infections or facilitate transmission of ESBL-E in the general population.

[Drug-resistant tuberculosis. Epidemiology, diagnostics and therapy]. / Medikamentenresistente Tuberkulose. Epidemiologie, Diagnostik, Therapie.

Drug-resistant tuberculosis (DR-TB) is one of the serious problems in the fight against tuberculosis on a global scale. This review article describes in brief the global epidemiology, diagnostics and treatment of DR-TB. The situation in Germany, Switzerland and Austria is addressed in detail. The article concludes with a presentation of current research topics in the field of resistant TB.

Methicillin-resistant Staphylococcus aureus as a cause of invasive infections in Central Africa: a case report and review of the literature.

INTRODUCTION: Community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) colonization and infection are increasingly being reported worldwide and are associated with severe illness. The vast majority of MRSA infections are skin and soft tissue infections, while invasive disease remains rare. In Western countries, the epidemiology of MRSA is well documented, but from Central Africa, reports on MRSA are very limited. METHODS: Case presentation and review of the literature. The clinical features, epidemiology, and characteristics of MRSA in Central Africa, as well as the treatment options, are discussed. We present a case of severe invasive CA-MRSA infection with pneumonia, pericarditis, and bacteremia in a previously healthy young woman in Gabon. Several virulence factors, like Panton-Valentine leukocidin and type I arginine catabolic mobile element, may play a role in the ability of CA-MRSA to cause severe invasive infections. Based on studies from Gabon and Cameroon (no reports were available from other countries), we find that the prevalence of MRSA is relatively low in this region. Treatment depends primarily on local prevalence and resistance profile of MRSA combined with clinical characteristics. CONCLUSION: Severe invasive infection with CA-MRSA is a rare disease presentation in Central Africa, where this pathogen is still relatively uncommon. However, cases of MRSA may be complicated by the human immunodeficiency virus (HIV) and tuberculosis epidemics, and also the limited availability of effective antibiotics.

Population dynamics of Staphylococcus aureus from Northeastern Nigeria in 2007 and 2012.

The population structure of Staphylococcus aureus is changing globally but the situation regarding dominant clones in sub-Saharan Africa is not clear. We therefore assessed changes in the population structure of clinical S. aureus isolates obtained in 2007 (n = 75) and 2012 (n = 75) from Northeastern Nigeria. A reduction in resistance to penicillin, gentamicin, erythromycin and clindamycin was observed in 2012. A decrease of methicillin resistance rates (13·3% to 8·0%) was associated with the decline of the ST241 MRSA clone. The proportion of Panton-Valentine leukocidin (PVL)-positive isolates also decreased from 65·3% to 44%, and was linked with the emergence of PVL-negative ST601 clone in 2012. The significant decline in antibiotic resistance in the study area is in contrast to the worldwide trend of increasing resistance rates.

Clonal structure of Staphylococcus aureus colonizing children with sickle cell anaemia and healthy controls.

Children with sickle cell anaemia (SCA) might carry hospital-associated bacterial lineages due to frequent hospital stays and antibiotic treatments. In this study we compared Staphylococcus aureus from SCA patients (n=73) and healthy children (n=143) in a cross-sectional study in Gabon. S. aureus carriage did not differ between children with SCA (n=34, 46∙6%) and controls matched for age, residence and sex (n=67, 46∙9%). Both groups shared similar S. aureus genotypes. This finding points towards a transmission of S. aureus between both groups in the community. We conclude that resistance rates from population-based studies with healthy participants could therefore also be used to guide treatment and prophylaxis of endogenous infections in children with SCA despite a different selection pressure.

Peripancreatic abscess supported by Bordetella hinzii.

We report a novel case of an infection with Bordetella hinzii, a pathogen usually detected in poultry, supporting a peripancreatic abscess formation as a complication of an acute necrotizing pancreatitis.

Panton-Valentine leukocidin-positive Staphylococcus aureus in skin and soft tissue infections from primary care patients.

OBJECTIVES: To characterize deep skin and soft tissue infections (dSSTI) caused by Panton-Valentine leukocidin (PVL)-positive versus PVL-negative Staphylococcus aureus isolates. METHODS: We performed a retrospective analysis of patients' records including S. aureus isolates from outpatients with dSSTI. Samples had been submitted by primary care physicians, i.e. general practitioners, surgeons, dermatologists and paediatricians, located in Berlin, Germany, in 2007-2017. Bacterial isolates were identified and tested for antimicrobial susceptibility by VITEK 2; PVL was detected by PCR. RESULTS: In total, 1199 S. aureus isolates from 1074 patients with dSSTI were identified, and 613 (51.1%) of 1199 samples were PVL+. The median age of patients with PVL+S. aureus was lower than in patients with PVL- S. aureus (34 years, range 0-88 years, vs. 44 years, range 0-98 years; p < 0.0001). PVL was associated with repeated/multiple samples compared to single sample submission (69/92, 75% vs. 448/982, 45.6%, p < 0.0001; odds ratio (OR), 3.6; 95% confidence interval (CI), 2.2-5.8). Interestingly, the highest PVL positivity rate was found in isolates from gluteal (82/108, 75.9%; OR, 3.6; 95% CI, 2-5) or axillary (76/123, 61.8%; OR, 2; 95% CI, 1.1-3.3) localizations compared to isolates from the arm. The PVL positivity rate did not increase over time. Yet we noticed an increase in the trimethoprim/sulfamethoxazole (SXT) resistance rate in PVL+ isolates, mainly methicillin-sensitive S. aureus, when considering SXT resistance rates of 2007-2012 versus 2013-2017 (35/226, 15.5% vs. 74/289, 25.6%; p 0.01). CONCLUSIONS: In outpatients, gluteal and axillary dSSTI are indicative of PVL+S. aureus. Providing SXT as a complementary treatment for dSSTI should be based on susceptibility testing.

A child with soft-tissue infection and lymphadenitis.

We report a case of a soft-tissue infection with Francisella philomiragia, a rare opportunistic pathogen in individuals with chronic granulomatous disease.

Acquisition and colonization dynamics of antimicrobial-resistant bacteria during international travel: a prospective cohort study.

OBJECTIVES: Travellers may be colonized with antimicrobial-resistant bacteria on return, but little is known about colonization during travel. Our objectives were to assess the acquisition and colonization dynamics during the stay abroad for a broad range of antimicrobial-resistant bacteria and resistance phenotypes and to identify risk factors for faecal carriage of antimicrobial-resistant bacteria. METHODS: German and Dutch participants (n = 132) of this prospective cohort study (2016-2018) completed a questionnaire on risk factors and provided daily stool samples before, during, and after travel. Samples were screened for extended-spectrum ß-lactamase producing Enterobacterales (ESBL-E), carbapenem-resistant (CarbR-GN), and non-intrinsically colistin-resistant Gram-negative rods (ColR-GN), vancomycin-resistant Enterococcus faecium/faecalis (VRE), and Clostridioides difficile. RESULTS: Colonization rates reached a plateau within a week after departure fluctuating around 48.5% (63/130) and 58.4% (45/77, ESBL-E), 10.4% (11/106) and 23.4% (18/77, ColR-GN), or 3.0% (4/132) and 6.8% (8/118, CarbR-GN). Colonization rates after the travel were 46.2% (61/132, ESBL-E), 9.0% (12/132, ColR-GN), and 3.4% (5/132, CarbR-GN). Travellers carried mcr-1- (15/132; 11.4%) or blaNDM-positive (4/132; 3.0%) Enterobacterales. A vegetarian diet was associated with a lower risk for the acquisition of ESBL-E (OR = 0.4, p 0.04) and ColR-GN (OR = 0.1, p 0.01) during travel in a multivariable model. Similarly, travellers visiting friends and relatives had a lower risk for the acquisition of ESBL-E (OR = 0.3, p 0.009) and CarbR-GN (OR = 0.3, p 0.01). VRE and C. difficile were not detected. CONCLUSION: The number of travellers with a temporary colonization during the journey exceeded the number of travellers still colonized after return.

Whole genome sequencing reveals a prolonged and spatially spread nosocomial outbreak of Panton-Valentine leucocidin-positive meticillin-resistant Staphylococcus aureus (USA300).

BACKGROUND: Whole genome sequencing (WGS) helps to better investigate the transmission and characterization of meticillin-resistant Staphylococcus aureus (MRSA) strains. AIM: We describe the detection and unfolding of a prolonged and spatially distributed nosocomial outbreak of Panton-Valentine leucocidin (PVL)-positive MRSA ST8 (USA300). METHODS: The outbreak was detected by the combination of whole genome sequence (WGS)-based typing, which is implemented for routine surveillance of multidrug-resistant bacteria in our institution, and in-depth epidemiological investigation. To investigate the source, processes were observed and environmental sampling performed. To contain the outbreak, regular and direct personal contact with the healthcare workers (HCWs) was maintained and staff education implemented. FINDINGS: The outbreak took place between October 2016 and November 2017 and included five patients who were treated in two different departments as inpatients and outpatients; three were infected, two were colonized. Additionally, three HCWs carried the outbreak strain. The strain was not found in the hospital environment. Only through non-mediated communication did the source become apparent. Decolonization of HCWs and infection control measures led to a resolution of the outbreak. CONCLUSION: WGS helped to reveal an outbreak that otherwise might have stayed undetected. Nonetheless, epidemiological investigation is needed to trace the nosocomial transmission. The importance of personal communication in infection control cannot be overstated.

Implications of identifying the recently defined members of the Staphylococcus aureus complex S. argenteus and S. schweitzeri: a position paper of members of the ESCMID Study Group for Staphylococci and Staphylococcal Diseases (ESGS).

BACKGROUND: Staphylococcus argenteus and Staphylococcus schweitzeri, previously known as divergent Staphylococcus aureus clonal lineages, have been recently established as novel, difficult-to-delimit, coagulase-positive species within the S. aureus complex. Methicillin-resistant strains of S. argenteus are known from Australia and the UK. Knowledge of their epidemiology, medical significance and transmission risk is limited and partly contradictory, hampering definitive recommendations. There is mounting evidence that the pathogenicity of S. argenteus is similar to that of 'classical' S. aureus, while as yet no S. schweitzeri infections have been reported. AIM: To provide decision support on whether and how to distinguish and report both species. SOURCES: PubMed, searched for S. argenteus and S. schweitzeri. CONTENT: This position paper reviews the main characteristics of both species and draws conclusions for microbiological diagnostics and surveillance as well as infection prevention and control measures. IMPLICATIONS: We propose not distinguishing within the S. aureus complex for routine reporting purposes until there is evidence that pathogenicity or clinical outcome differ markedly between the different species. Primarily for research purposes, suitably equipped laboratories are encouraged to differentiate between S. argenteus and S. schweitzeri. Caution is urged if these novel species are explicitly reported. In such cases, a specific comment should be added (i.e. 'member of the S.aureus complex') to prevent confusion with less- or non-pathogenic staphylococci. Prioritizing aspects of patient safety, methicillin-resistant isolates should be handled as recommended for methicillin-resistant Staphylococcus aureus (MRSA). In these cases, the clinician responsible should be directly contacted and informed by the diagnosing microbiological laboratory, as they would be for MRSA. Research is warranted to clarify the epidemiology, clinical impact and implications for infection control of such isolates.

First description of a local Coprinopsis cinerea skin and soft tissue infection.

Coprinopsis cinerea is an environmental fungus which can cause disseminated infections in immunocompromised patients, often leading to death. Here we report the case of a paediatric patient with an invasive wound infection due to C. cinerea, which was successfully treated with surgical debridement and oral posaconazole.

Assessment of thermal effects in a model of the human head implanted with a wireless active microvalve for the treatment of glaucoma creating a filtering bleb.

A 3D anatomical computational model is developed to assess thermal effects due to exposure to the electromagnetic field required to power a new investigational active implantable microvalve for the treatment of glaucoma. Such a device, located in the temporal superior eye quadrant, produces a filtering bleb, which is included in the geometry of the model, together with the relevant ocular structures. The electromagnetic field source-a planar coil-as well as the microvalve antenna and casing are also included. Exposure to the electromagnetic field source of an implanted and a non-implanted subject are simulated by solving a magnetic potential formulation, using the finite element method. The maximum SAR10 is reached in the eyebrow and remains within the limits suggested by the IEEE and ICNIRP standards. The anterior chamber, filtering bleb, iris and ciliary body are the ocular structures where more absorption occurs. The temperature rise distribution is also obtained by solving the bioheat equation with the finite element method. The numerical results are compared with the in vivo measurements obtained from four rabbits implanted with the microvalve and exposed to the electromagnetic field source.

First description of an Anaerobiospirillum succiniciproducens prosthetic joint infection.

Anaerobiospirillum succiniciproducens belongs to the normal flora of cats and dogs and can rarely infect humans. Here, we report the first case of an A. succiniciproducens prosthetic joint infection.

Unveiling the molecular basis of antimicrobial resistance in Staphylococcus aureus from the Democratic Republic of the Congo using whole genome sequencing.

Staphylococcus aureus from sub-Saharan Africa is frequently resistant to antimicrobial agents that are commonly used to treat invasive infections in resource-limited settings. The underlying mechanisms of resistance are largely unknown. We therefore performed whole genome sequencing (WGS) on S. aureus from the Democratic Republic of the Congo (DRC) to analyse the genetic determinants of antimicrobial resistance. One hundred S. aureus samples were collected from community-associated asymptomatic nasal carriers in the metropolitan area of Kinshasa, DRC, between 2013 and 2014. Phenotypic resistance against 15 antimicrobial agents was compared to the genotypic results that were extracted from WGS data using Mykrobe predictor and the SeqSphere(+) software that screened for 106 target genes associated with resistance. Isolates were phenotypically resistant against penicillin (97%, n=97), trimethoprim (72%, n=72) and tetracycline (54%, n=45). Thirty-three isolates (33%) were methicillin-resistant S. aureus (MRSA). Of these, nine isolates (27.3%) were oxacillin-susceptible MRSA (OS-MRSA) and belonged to ST8 (t1476). The Y195F mutation of FemA was associated with OS-MRSA (p 0.015). The majority of trimethoprim resistant isolates carried dfrG. Tetracycline resistance was associated with tet(K). The concordance between phenotypic susceptibility testing and both WGS analysis tools was similar and ranged between 96% and 100%. In conclusion, a high proportion of OS-MRSA in the DRC was linked to mutations of FemA. Genotypic and phenotypical antimicrobial susceptibility testing showed high concordance. This encourages the future use of WGS in routine antimicrobial susceptibility testing.

Environmental health sciences center task force review on halogenated organics in drinking water.

The disinfection of drinking water by chlorination has in recent years come under closer scrutiny because of the potential hazards associated with the production of stable chlorinated organic chemicals. Organic chemical contaminants are common to all water supplies and it is now well-established that chlorinated by-products are obtained under conditions of disinfection, or during tertiary treatment of sewage whose products can ultimately find their way into drinking water supplies. Naturally occurring humic substances which are invariably present in drinking waters are probably the source of chloroform and other halogenated methanes, and chloroform has shown up in every water supply investigated thus far.The Environmental Protection Agency is charged with the responsibility of assessing the public health effects resulting from the consumption of contaminated drinking water. It has specifically undertaken the task of determining whether organic contaminants or their chlorinated derivatives have a special impact, and if so, what alternatives there are to protect the consumer against bacterial and viral diseases that are transmitted through infected drinking waters. The impetus to look at these chemicals is not entirely without some prima facie evidence of potential trouble. Epidemiological studies suggested a higher incidence of cancer along the lower Mississippi River where the contamination from organic chemicals is particularly high. The conclusions from these studies have, to be sure, not gone unchallenged.The task of assessing the effects of chemicals in the drinking water is a difficult one. It includes many variables, including differences in water supplies and the temporal relationship between contamination and consumption of the finished product. It must also take into account the relative importance of the effects from these chemicals in comparison to those from occupational exposure, ingestion of contaminated foods, inhalation of polluted air, and many others. The susceptibility of different age, genetic, and ethnic groups within the population must also be carefully considered. The present review discusses: the reasons for disinfection; the general occurrence of chlorinated organics in drinking water; the chemistry in the synthesis of chlorinated organics under aqueous conditions; and alternatives to chlorine for disinfection.

New epidemiology of Staphylococcus aureus infection in Africa.

Research on African Staphylococcus aureus has been largely neglected in the past, despite the cultural and geographical diversity in Africa, which has a significant impact on the epidemiology of this pathogen. The polarity between developed urban societies and remote rural populations (e.g. Pygmies), combined with close contact with animals (e.g. livestock and domestic animals, and wildlife), makes the epidemiology of S. aureus on the African continent unique and fascinating. Here, we try to draw an epidemiological picture of S. aureus colonization and infection in Africa, and focus on the wide spread of Panton-Valentine leukocidin-positive isolates, the emergence of the hypervirulent methicillin-resistant S. aureus (MRSA) clone USA300, and the dissemination of the typical African clone MRSA sequence type 88.

Trends in antimicrobial non-susceptibility in methicillin-resistant Staphylococcus aureus from Germany (2004-2011).

We analysed trends in antimicrobial non-susceptibility in methicillin-resistant Staphylococcus aureus (MSRA) from Germany to assess the impact of the changing population structure of MRSA on antimicrobial resistance rates. During two large nationwide multicentre studies in 2004-2005 and 2010-2011, we collected consecutively spa-genotyped MRSA isolates. The increase in non-susceptibility rates for tetracycline and trimethoprim-sulphamethoxazole was associated with the spread of livestock-associated MRSA. A decrease in non-susceptibility rates for aminoglycosides and quinolones affected all major lineages (spa-clonal complexes 003, 008, and 032). All isolated remained susceptible to glycopeptides and linezolid.