Consistent biofilm formation by Streptococcus pyogenes emm 1 isolated from patients with necrotizing soft tissue infections

Objectives: Biofilm formation has been demonstrated in muscle and soft tissue samples from patients with necrotizing soft tissue infection (NSTI) caused by Streptococcus pyogenes, but the clinical importance of this observation is not clear. Although M-protein has been shown to be important for in vitro biofilm formation in S. pyogenes, the evidence for an association between emm type and biofilm forming capacity is conflicting. Here we characterize the biofilm forming capacity in a collection of S. pyogenes isolates causing NSTI, and relate this to emm type of the isolates and clinical characteristics of the patients. Methods: Bacterial isolates and clinical data were obtained from NSTI patients enrolled in a multicenter prospective observational study. Biofilm forming capacity was determined using a microtiter plate assay. Results: Among 57 cases, the three most frequently encountered emm types were emm1 (n = 22), emm3 (n = 13), and emm28 (n = 7). The distribution of biofilm forming capacity in emm1 was qualitatively (narrow-ranged normal distribution) and quantitatively (21/22 isolates in the intermediate range) different from other emm types (wide ranged, multimodal distribution with 5/35 isolates in the same range as emm1). There were no significant associations between biofilm forming capacity and clinical characteristics of the patients. Conclusions: The biofilm forming capacity of emm1 isolates was uniform and differed significantly from other emm types. The impact of biofilm formation in NSTI caused by S. pyogenes on clinical outcomes remains uncertain.publishedVersio

Carbapenem‐resistant enterobacteriaceae—implications for treating acute leukemias, a subgroup of hematological malignancies

This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).Acute leukemias (AL) are a group of aggressive malignant diseases associated with a high degree of morbidity and mortality. Patients with AL are highly susceptible to infectious diseases due to the disease itself, factors attributed to treatment, and specific individual risk factors. Enterobacteriaceae presence (e.g., Klebsiella pneumonia and Escherichia coli) is a frequent cause of bloodstream infections in AL patients. Carbapenem-resistant Enterobacteriaceae (CRE) is an emerging health problem worldwide; however, the incidence of CRE varies greatly between different regions. Carbapenem resistance in Enterobacteriaceae is caused by different mechanisms, and CRE may display various resistance profiles. Bacterial co-expression of genes conferring resistance to both broad-spectrum β-lactam antibiotics (including carbapenems) and other classes of antibiotics may give rise to multidrug-resistant organisms (MDROs). The spread of CRE represents a major treatment challenge for clinicians due to lack of randomized clinical trials (RCTs), a limited number of antibiotics available, and the side-effects associated with them. Most research concerning CRE infections in AL patients are limited to case reports and retrospective reviews. Current research recommends treatment with older antibiotics, such as polymyxins, fosfomycin, older aminoglycosides, and in some cases carbapenems. To prevent the spread of resistant microbes, it is of pivotal interest to implement antibiotic stewardship to reduce broad-spectrum antibiotic treatment, but without giving too narrow a treatment to neutropenic infected patients.publishedVersio

Carbapenem-Resistant Enterobacteriaceae—Implications for Treating Acute Leukemias, a Subgroup of Hematological Malignancies

Acute leukemias (AL) are a group of aggressive malignant diseases associated with a high degree of morbidity and mortality. Patients with AL are highly susceptible to infectious diseases due to the disease itself, factors attributed to treatment, and specific individual risk factors. Enterobacteriaceae presence (e.g., Klebsiella pneumonia and Escherichia coli) is a frequent cause of bloodstream infections in AL patients. Carbapenem-resistant Enterobacteriaceae (CRE) is an emerging health problem worldwide; however, the incidence of CRE varies greatly between different regions. Carbapenem resistance in Enterobacteriaceae is caused by different mechanisms, and CRE may display various resistance profiles. Bacterial co-expression of genes conferring resistance to both broad-spectrum β-lactam antibiotics (including carbapenems) and other classes of antibiotics may give rise to multidrug-resistant organisms (MDROs). The spread of CRE represents a major treatment challenge for clinicians due to lack of randomized clinical trials (RCTs), a limited number of antibiotics available, and the side-effects associated with them. Most research concerning CRE infections in AL patients are limited to case reports and retrospective reviews. Current research recommends treatment with older antibiotics, such as polymyxins, fosfomycin, older aminoglycosides, and in some cases carbapenems. To prevent the spread of resistant microbes, it is of pivotal interest to implement antibiotic stewardship to reduce broad-spectrum antibiotic treatment, but without giving too narrow a treatment to neutropenic infected patients.publishedVersio

A New Human Challenge Model for Testing Heat-Stable Toxin-Based Vaccine Candidates for Enterotoxigenic Escherichia Coli Diarrhea - Dose Optimization, Clinical Outcomes, and CD4+ T Cell Responses

Enterotoxigenic Escherichia coli (ETEC) are a common cause of diarrheal illness in young children and travelers. There is yet no licensed broadly protective vaccine against ETEC. One promising vaccine development strategy is to target strains expressing the heat-stable toxin (ST), particularly the human ST (STh), since infections with these strains are among the leading causes of diarrhea in children in low-and-middle income countries. A human challenge model based on an STh-only ETEC strain will be useful to evaluate the protective efficacy of new ST-based vaccine candidates. To develop this model, we experimentally infected 21 healthy adult volunteers with the epidemiologically relevant STh-only ETEC strain TW10722, identified a suitable dose, assessed safety, and characterized clinical outcomes and immune responses caused by the infection. Doses of 1×1010 colony-forming units (CFU) of TW10722 gave a suitable attack risk of 67% for moderate or severe diarrhea and an overall diarrhea attack risk of 78%. Non-diarrheal symptoms were mostly mild or moderate, and there were no serious adverse events. During the first month after ingesting the challenge strain, we measured significant increases in both activated CD4+ T cells and levels of serum IgG and IgA antibodies targeting coli surface antigen 5 (CS5) and 6 (CS6), as well as the E. coli mucinase YghJ. The CS5-specific CD4+ T cell and antibody responses were still significantly elevated one year after experimental infection. In conclusion, we have developed a safe STh-only ETEC-based human challenge model which can be efficiently used in Phase 2B trials to evaluate the protective efficacy of new ST-based vaccine candidates.publishedVersio

Countrywide outbreak of Pseudomonas aeruginosa in hospitals caused by premoistened non-sterile washcloths, Norway, 2021-2022

Source at https://www.fhi.no/I november 2021 ble Folkehelseinstituttet varslet om at tre intensivpasienter hadde dødd av blodbaneinfeksjon med bakterien Pseudomonas aeruginosa ved Universitetssykehuset Nord-Norge i Tromsø i løpet av kort tid. De hadde identiske isolater forenlig med et klonalt utbrudd. Helgenomsekvensering viste at det var en ny sekvenstype, ST3875, som ikke har vært påvist i Norge eller andre land. Nye tilfeller uten epidemiologiske sammenhenger, ble etter hvert funnet i flere andre sykehus, noe som indikerte en felles smittekilde. Den 17. januar 2022 var det påvist utbruddstilfeller i tre av fire helseregioner, og det ble 19. januar erkjent som et nasjonalt utbrudd. FHI overtok da koordinering av utbruddsarbeidet, og 20. januar ble det etablert en Sentral utbruddsgruppe med fagpersoner fra alle helseregionene. Den 21. januar var det 23 tilfeller i 9 sykehus i 3 regioner. Kasusdefinisjonen var en person med laboratoriebekreftet P. aeruginosa ST3875 fra oktober 2021 i sykehus i Norge, uavhengig av avdeling. Etter systematiske laboratorieundersøkelser av over 300 produkter påviste Oslo Universitetssykehus 18. mars 2022 utbruddsbakterien i pre-fuktede engangs vaskekluter av merket Oasis BedBath Unperfumed produsert i Lancashire, England. Sykehusene sluttet umiddelbart å bruke produktene. Vaskeklutene er definert som et kosmetisk produkt, og Mattilsynet er tilsynsmyndighet. Mattilsynet avdekket at produsenten og importøren ikke hadde full oversikt over produksjonslinjene og hvilke produkter som var forurenset. Det ble også avdekket at P. aeruginosa var blitt påvist i produkter under den interne kvalitetskontrollen i september 2021, uten at produktene var blitt stanset. Den 14. april tilbakekalte den engelske produsenten Vernacare produktene fra markedet både i Norge og internasjonalt. Per 14. juni 2022 omfattet utbruddet 388 tilfeller i 40 sykehus. Gjennomsnittsalder var 68 år og median alder 70 år (interkvartilområde 59- 79 år). Flertallet (63 %) av tilfellene var menn, og seks sykehus rapporterte Pseudomonas som sterkt medvirkende årsak til død hos totalt 8 tilfeller. Til sammen hadde 15 % av tilfellene ST3875 i blodkultur, 21 % i luftveier, 38 % i urin, 19 % i sår og 7 % i andre prøvematerialer, noe som tydet på flere mulige inngangsporter for bakterien. Antall nye tilfeller falt raskt etter at kilden var identifisert, og bruk av produktet ble stoppet i sykehus

The decline of the impetigo epidemic caused by the epidemic European fusidic acid-resistant impetigo clone: an 11.5-year population-based incidence study from a community in Western Norway

Background: From around the year 2000, Northern Europe experienced a rise in impetigo caused by Staphylococcus aureus resistant to fusidic acid. A single clone of S. aureus was found to be the bacterial pathogen involved in the impetigo outbreak in Norway, Sweden, the UK and Ireland, termed ‘the epidemic European fusidic acid-resistant impetigo clone’ (EEFIC). We have followed the incidence of impetigo during the years 2001–2012 based on all patients in general practice in the island community of Austevoll, Western Norway. We previously reported a marked decline of impetigo incidence in Austevoll, from 0.0260 cases per person-year in 2002 to 0.0038 in 2009. This article explores indications of an end to the impetigo epidemic caused by the EEFIC clone. Methods: All four general practitioners (GPs) in the community (mean population = 4400) were asked to diagnose impetigo in a uniform way and to take bacterial specimens from all impetigo cases. Phenotypic characteristics of specimen bacteria were determined for the whole period and molecular analyses were performed on isolates in the period 2008–2012. Results: We observed a further decline in incidence of impetigo in Austevoll in the study period. The proportion of fusidic acid-resistant S. aureus isolates decreased during the period 2002–2012, with a mean of 80% in the epidemic years of 2002–2004, 55% in 2005–2009, and 6% in 2010–2012. In total, 44 S. aureus isolates from impetigo were subject to molecular analyses in the period 2008–2012, and 11 were found to be related to the EEFIC. All EEFIC isolates were found in 2008–2009, with no new isolates in 2010–2012. Conclusion: There is an apparent end to the impetigo epidemic related to the EEFIC in this population in Western Norway

Consistent biofilm formation by Streptococcus pyogenes emm 1 isolated from patients with necrotizing soft tissue infections

Objectives: Biofilm formation has been demonstrated in muscle and soft tissue samples from patients with necrotizing soft tissue infection (NSTI) caused by Streptococcus pyogenes, but the clinical importance of this observation is not clear. Although M-protein has been shown to be important for in vitro biofilm formation in S. pyogenes, the evidence for an association between emm type and biofilm forming capacity is conflicting. Here we characterize the biofilm forming capacity in a collection of S. pyogenes isolates causing NSTI, and relate this to emm type of the isolates and clinical characteristics of the patients. Methods: Bacterial isolates and clinical data were obtained from NSTI patients enrolled in a multicenter prospective observational study. Biofilm forming capacity was determined using a microtiter plate assay. Results: Among 57 cases, the three most frequently encountered emm types were emm1 (n = 22), emm3 (n = 13), and emm28 (n = 7). The distribution of biofilm forming capacity in emm1 was qualitatively (narrow-ranged normal distribution) and quantitatively (21/22 isolates in the intermediate range) different from other emm types (wide ranged, multimodal distribution with 5/35 isolates in the same range as emm1). There were no significant associations between biofilm forming capacity and clinical characteristics of the patients. Conclusions: The biofilm forming capacity of emm1 isolates was uniform and differed significantly from other emm types. The impact of biofilm formation in NSTI caused by S. pyogenes on clinical outcomes remains uncertain

Streptococcus dysgalactiae Bloodstream Infections, Norway, 1999–2021

Streptococcus dysgalactiae increasingly is recognized as a pathogen of concern for human health. However, longitudinal surveillance data describing temporal trends of S. dysgalactiae are scarce. We retrospectively identified all β-hemolytic streptococcal bloodstream infections reported in Bergen, in western Norway, during 1999–2021. To explore S. dysgalactiae disease burden in a broader context, we mapped the incidence of all microbial species causing bloodstream infections during 2012–2021. We found S. dysgalactiae incidence rates substantially increased during the study period; by 2021, S. dysgalactiae was the fifth most common pathogen causing bloodstream infections in our region. We noted genotypic shifts and found that the rising trend was related in part to the introduction and expansion of the stG62647 emm-type. S. dysgalactiae is among the most common causes of bloodstream infections in western Norway, and increased surveillance and unambiguous species identification are needed to monitor the disease burden attributable to this pathogen