Elevated risk of invasive group A streptococcal disease and host genetic variation in the human leucocyte antigen locus.

Invasive group A streptococcal (GAS) disease is uncommon but carries a high case-fatality rate relative to other infectious diseases. Given the ubiquity of mild GAS infections, it remains unclear why healthy individuals will occasionally develop life-threatening infections, raising the possibility of host genetic predisposition. Here, we present the results of a case-control study including 43 invasive GAS cases and 1540 controls. Using HLA imputation and linear mixed models, we find each copy of the HLA-DQA1*01:03 allele associates with a twofold increased risk of disease (odds ratio 2.3, 95% confidence interval 1.3-4.4, P = 0.009), an association which persists with classical HLA typing of a subset of cases and analysis with an alternative large control dataset with validated HLA data. Moreover, we propose the association is driven by the allele itself rather than the background haplotype. Overall this finding provides impetus for further investigation of the immunogenetic basis of this devastating bacterial disease.

Study of the influence of platinum, palladium and rhodium on duckweed (Lemna minor).

OBJECTIVES: Road traffic pollutants and the residues of cytostatics that are widely used in anti-cancer therapy are a significant sources of platinum group elements (PGE; Pt, Pd and Rh) in environment. These metals can migrate into sewage and thus pollute surface waters. The purpose of our study was to evaluate the effect of PtCl4 on the antioxidant and enzymatic activity of duckweed (Lemna minor), a bioindicator of the aquatic environment. METHODS: The study was performed using a 7-day conventional test based on the OECD 221 (CSN EN ISO 20079)--Lemna sp. Growth Inhibition Test. We also conducted a microbiotest to analyse the effects of PtC4, PdCl2 and RhCl3 on the morphology and vegetative growth of colonies of this plant and compared their inhibitory effects during the microbiotest. RESULTS: We observed inhibition of colony growth and clear morphological changes. Antioxidant and enzymatic activities increased with platinum doses increased. The 168hEC50 of PtCl4 was 12.16 µM (95% confidence interval = 9.88-14.44) and the 168hEC50 of PdCl2 was 50.39 (95% confidence interval = 23.83-76.96). The greatest inhibition of growth by RhCl3 was observed at 25 µM. CONCLUSIONS: The obtained results suggest that L. minor phytotoxicity tests should be widely used in the biomonitoring.

Comparison of the effect of platinum on producers in aquatic environment.

OBJECTIVES: An enhanced worldwide application of platinum group elements (PGE), in particular platinum, has been observed during recent decades. An increased concentration of PGE was determined in collected samples of great amount of aqueous ecosystems.The aim was to compare phytotoxic effect of platinum (PtCl4) by performing two different bioassays on green algae Pseudokirchneriella subcapitata and macrophyte duckweed, Lemna minor. MEDTHODS: The algal experiment (Pseudokichneriella subcapitata) followed OECD 201, the concentration row for PtCl4 was: 0.05; 0.01; 0.25; 0.5; 1 µM. The duckweed (Lemna minor) experiment was conducted according to OECD 221, employed PtCl4 concentrations were: 5; 10; 25; 50; 100 µM. Plants were cultivated as a microbiotest, using micro-volumes. RESULTS: The results of the algal test showed significant growth inhibition of the final biomass. The values of 72hEC5(µ), 72hEC10(µ), 72hEC20(µ) counted on a basis of average specific growth rate (µ) were 0.31 µM, 0.58 µM and 1.12 µM of PtCl4, respectively. The values, obtained on a basis of the area under the growth curves (A), were 0.04 µM (72hEC5(A)), 0.24 µM (72hEC10(A)) and 0.64 µM (72hEC20(A)). The experiment with duckweed showed 50% of growth inhibition and the values of 168hEC50(µ) were 19.55 µM and 168hEC50(A) 13.63 µM of PtCl4. CONCLUSION: The fronds of duckweed showed strong adverse effect of platinum influence (chlorosis, necrosis). The algal test and the estimation of 72hEC5(A) appears to be the most sensitive.

Introduction of PCR testing reveals a previously unrecognized burden of yersiniosis in Hampshire, UK.

Introduction. Current testing practices for yersiniosis mean that its true incidence and epidemiology are not well understood. In mid-2016, the introduction of testing via a multiplex gastrointestinal PCR panel at Portsmouth hospital laboratory in Hampshire, UK, resulted in a marked increase in the number of Yersinia cases identified locally.Aim. Here we describe the epidemiology and microbiology of Yersinia cases identified at Portsmouth laboratory following the introduction of PCR testing.Methodology. A case was defined as a person with a stool specimen in which Yersinia was detected by PCR and/or culture at Portsmouth NHS Trust laboratory between 1 January 2014 and 31 December 2018. A case list was created from laboratory data submitted by Portsmouth laboratory to Public Health England (PHE), updated with speciation and serotyping data from the PHE reference laboratory. Descriptive analysis was performed.Results. Over 30 months following introduction of PCR testing, 199 cases were confirmed with Yersinia, compared to two cases in the preceding 30 months. This corresponds to a rate of 13.8 and 0.1 per 100 000 population per year respectively (P<0.0001). In total, 85% of tested isolates were Y. enterocolitica, belonging to multiple serotypes, and the rest belonged to a range of Y. enterocolitica-like species.Conclusions. Introduction of PCR testing led to the identification of a previously unrecognized burden of yersiniosis in Hampshire. The diversity of species and serotypes suggests heterogeneity in sources and transmission routes. Further research on exposures, risk factors and clinical sequalae is needed to improve our understanding of the clinical and public health impact.

Clinical and microbiological characteristics of severe Streptococcus pyogenes disease in Europe.

In an attempt to compare the epidemiology of severe Streptococcus pyogenes infection within Europe, prospective data were collected through the Strep-EURO program. Surveillance for severe cases of S. pyogenes infection diagnosed during 2003 and 2004 was undertaken in 11 countries across Europe by using a standardized case definition and questionnaire. Patient data as well as bacterial isolates were collected and characterized by T and M/emm typing, and selected strains were analyzed for the presence of superantigen genes. Data were analyzed to compare the clinical and microbiological patterns of the infections across the participating countries. A total of 4,353 isolates were collected from 5,521 cases with severe S. pyogenes infections who were identified. A wide diversity of M/emm types (n = 104) was found among the S. pyogenes clinical isolates, but the M/emm type distribution varied broadly between participating countries. The 10 most predominant M/emm types were M/emm type 1 (M/emm1), M/emm28, M/emm3, M/emm89, M/emm87, M/emm12, M/emm4, M/emm83, M/emm81, and M/emm5, in descending order. A correlation was found between some specific disease manifestations, the age of the patients, and the emm types. Although streptococcal toxic shock syndrome and necrotizing fasciitis were caused by a large number of types, they were particularly associated with M/emm1 and M/emm3. The emm types included in the 26-valent vaccine under development were generally well represented in the present material; 16 of the vaccine types accounted for 69% of isolates. The Strep-EURO collaborative program has contributed to enhancement of the knowledge of the spread of invasive disease caused by S. pyogenes within Europe and encourages future surveillance by the notification of cases and the characterization of strains, which are important for vaccination strategies and other health care issues.

Epidemiology of severe Streptococcus pyogenes disease in Europe.

The past 2 decades have brought worrying increases in severe Streptococcus pyogenes diseases globally. To investigate and compare the epidemiological patterns of these diseases within Europe, data were collected through a European Union FP-5-funded program (Strep-EURO). Prospective population-based surveillance of severe S. pyogenes infection diagnosed during 2003 and 2004 was undertaken in 11 countries across Europe (Cyprus, the Czech Republic, Denmark, Finland, France, Germany, Greece, Italy, Romania, Sweden, and the United Kingdom) using a standardized case definition. A total of 5,522 cases were identified across the 11 countries during this period. Rates of reported infection varied, reaching 3/100,000 population in the northern European countries. Seasonal patterns of infection showed remarkable congruence between countries. The risk of infection was highest among the elderly, and rates were higher in males than in females in most countries. Skin lesions/wounds were the most common predisposing factor, reported in 25% of cases; 21% had no predisposing factors reported. Skin and soft tissue were the most common foci of infection, with 32% of patients having cellulitis and 8% necrotizing fasciitis. The overall 7-day case fatality rate was 19%; it was 44% among patients who developed streptococcal toxic shock syndrome. The findings from Strep-EURO confirm a high incidence of severe S. pyogenes disease in Europe. Furthermore, these results have identified targets for public health intervention, as well as raising awareness of severe S. pyogenes disease across Europe.

Campylobacter fetus prosthetic valve endocarditis presenting as a stroke.

INTRODUCTION: Campylobacter is a common pathogen of the gastrointestinal tract, but invasive disease is rare. Campylobacter fetus can play a role in osteomyelitis, meningitis and joint infection and has a prediliction for the vascular endothelium, causing mycotic aneurysms, thrombophlebitis and endocarditis. Here we present a case of prosthetic valve endocarditis caused by C. fetus and a review of the literature. CASE PRESENTATION: An 85-year-old woman with a tissue aortic valve replacement and atrial fibrillation was admitted to hospital with tonic-clonic seizures, right-sided hemiparesis, facial droop and hemianopia. Multiple cerebral emboli were seen on magnetic resonance imaging of the brain. Blood cultures grew C. fetus and an echocardiogram showed thickening and restricted movement of the aortic valve, a significant difference from an echocardiogram done 2 months before when the same organism was again isolated in blood cultures. She improved after treatment with 6 weeks of amoxicillin and 2 weeks of synergistic gentamicin for prosthetic valve endocarditis. CONCLUSION: There have only been five previously reported cases of C. fetus prosthetic valve endocarditis and this is the only patient who presented as a stroke. The majority of surviving patients required replacement of the affected valve with only one other patient surviving in the absence of surgery. No guidelines exist on the optimum treatment of C. fetus endocarditis and this case reports adds to the growing literature on the appropriate management for this rare and potentially devastating disease.

Group A streptococci from invasive-disease episodes in Poland are remarkably divergent at the molecular level.

Forty-one clinical isolates of group A streptococcus (GAS) were recovered in Poland from patients with severe invasive infections and were analyzed by phenotypic and genotypic techniques. All isolates were characterized by determining their susceptibilities to antimicrobial agents and by determining their types by pulsed-field gel electrophoresis, multilocus sequence typing, emm typing, and the detection of five streptococcal pyrogenic exotoxin genes (speA, speB, speC, speF, ssa). The isolates studied were fully susceptible to penicillin G, levofloxacin, quinupristin-dalfopristin, and linezolid. Resistance to tetracycline, chloramphenicol, and erythromycin was detected in 46.3, 12.1, and 9.8% of the isolates, respectively. A total of 23 different emm sequence types were identified, of which emm1 and emm12 (19.5% each) were the most common, followed by emm81, emm44/61, and emm85. All the emm1 isolates had the speA2 allele. Twenty-three unrelated sequence types (STs) were identified, with the most frequent STs, ST28 and ST36, corresponding to emm1 and emm12, respectively. Six newly found STs (STs 375, 376, 377, 378, 379, and 385) corresponded to emm types 74, 102, 77, 76, 84 and 63, respectively. The emm1 type and the presence of speA2 gene were associated with the severity of GAS infections. This work presents the first molecular study on Polish invasive GAS isolates.