Spriječavanje klijanja spora i rasta Bacillus megaterium kombinirajući toplinsku obradu i prirodne antimikrobne spojeve

Natural antimicrobials are an alternative to the use of chemically synthesized preservatives and other technological treatments. They have the advantage of not being rejected by consumers because of their natural origin. However, prior to their usage at a food factory scale, their precise effects on microorganisms have to be known. Nisin, a bacteriocin, and carvacrol and thymol, phenolic compounds present in the essential oil fraction of Oreganum and Thymus plants, have been shown to inhibit growth of different bacteria. This research was conducted to show the effect of a thermal treatment, applied previously, on the growth of B. megaterium cells in a culture medium with and without nisin, carvacrol and thymol. It has been shown that a thermal treatment able to kill 90 % of the spore population of B. megaterium had little effect on the growth of the survivors in nutrient broth at 30 °C. Nisin, in a concentration of 0.05 mM, did not affect greatly the growth of unheated B. megaterium. When the same concentration of nisin was applied to the survivors of the heat treatment, lag phase was further increased and growth rate decreased. Thymol, applied at a concentration of 0.6 mM, increased the lag phase duration almost three times, although it did not change the growth rate. Although carvacrol, at the same concentration (0.6 mM), did reduce the growth rate to half its original value, it did not increase the lag phase duration significantly (only twice), resulting in a quite similar growth curve. The combination of thymol and carvacrol at these high doses (0.6 mM) resulted in a further increase of the lag phase and significant decrease of the growth rate. When carvacrol and/or thymol were combined with a previous thermal treatment (able to kill 90 % of the population), the growth of the survivors was inhibited for at least seven days. Therefore a combination of moderate conditions could be effective to control spoilage by sporeforming bacteria.Prirodna antimikrobna sredstva su alternativa kemijski sintetiziranim konzervansima i drugim tehnološkim postupcima. Njihova je prednost u tome što su zbog svoga prirodnog podrijetla prihvatljivi potrošačima. Prije njihove primjene u prehrambenoj industriji, potrebno je znati kako djeluju na mikroorganizme. Nisin, bakteriocin, te karvakrol i timol, fenolni spojevi prisutni u frakcijama eteričnog ulja biljaka Oreganum i Thymus, inhibiraju rast raznih bakterija. Opisano je istraživanje provedeno da bi se utvrdio učinak prethodno provedene toplinske obrade na rast stanica B. megaterium u podlozi s nisinom, karvakrolom i timolom te bez njih. Pokazalo se da toplinska obrada može usmrtiti 90 % populacije spora B. megaterium, a gotovo nikako ne utječe na rast preživjelih u hranjivoj podlozi pri 30 °C. 22 P.M. PERIAGO et al.: B. megaterium Spore Germination and Growth Inhibition, Food Technol. Biotechnol. 44 (1) 17–23 (2006) Nisin koncentracije od 0,05 mM nije bitno utjecao na rast toplinski neobra|enog B. megaterium. Kada se ista koncentracija nisina primijeni na preživjele spore, produlji se lag faza, a smanji brzina rasta. Timol koncentracije od 0,6 mM produžio je trajanje lag faze skoro 3 puta, a nije promijenio brzinu rasta. Iako je karvakrol iste koncentracije (0,6 mM) smanjio brzinu rasta na polovinu originalne vrijednosti, dužinu lag faze produžio je samo za 2 puta, što je rezultiralo skoro jednakom (0,6 mM) krivuljom rasta. Kombinacijom tih velikih koncentracija timola i karvakrola znatno je produljena lag faza i smanjena brzina rasta. Kada se karvakrol i/ili timol kombiniraju s prethodnom toplinskom obradom (pri čemu je uništeno 90 % populacije), rast preživjelih bio je inhibiran barem 7 dana. Stoga kombinacija jednostavnih uvjeta može biti djelotvorna u kontroli onečišćenja sa sporulirajućim bakterijam

Use of Frequency Distribution Functions to Establish Safe Conditions in Relation to the Foodborne Pathogen Bacillus cereus

Minimal processing implementation greatly depends on a detailed knowledge of the effects of preservation factors and their combinations on the spoilage and foodborne pathogenic microorganisms. The effectiveness of mild preservation conditions will become increasingly dependent on a more stochastic approach linking microbial physiological factors with product preservation factors. In this study, the validity of frequency distributions to efficiently describe the inactivation and growth of Bacillus cereus in the presence of natural antimicrobials (essential oils) has been studied. For this purpose, vegetative cells were exposed to 0.6 mM of thymol or cymene, obtaining survival curves that were best described by the distribution of Weibull, since a tailing effect was observed. B. cereus was also exposed in a growth medium to a low concentration (0.1 mM) of both antimicrobials, separately or combined, and the lag times obtained were fitted to a normal distribution, which allowed a description of dispersion of the start of growth. This allowed a more efficient evaluation of the experimental data to establish safe processing conditions according to accurate parameters and their implementation in risk assessment

Use of Frequency Distribution Functions to Establish Safe Conditions in Relation to the Foodborne Pathogen Bacillus cereus

Minimal processing implementation greatly depends on a detailed knowledge of the effects of preservation factors and their combinations on the spoilage and foodborne pathogenic microorganisms. The effectiveness of mild preservation conditions will become increasingly dependent on a more stochastic approach linking microbial physiological factors with product preservation factors. In this study, the validity of frequency distributions to efficiently describe the inactivation and growth of Bacillus cereus in the presence of natural antimicrobials (essential oils) has been studied. For this purpose, vegetative cells were exposed to 0.6 mM of thymol or cymene, obtaining survival curves that were best described by the distribution of Weibull, since a tailing effect was observed. B. cereus was also exposed in a growth medium to a low concentration (0.1 mM) of both antimicrobials, separately or combined, and the lag times obtained were fitted to a normal distribution, which allowed a description of dispersion of the start of growth. This allowed a more efficient evaluation of the experimental data to establish safe processing conditions according to accurate parameters and their implementation in risk assessment

Spriječavanje klijanja spora i rasta Bacillus megaterium kombinirajući toplinsku obradu i prirodne antimikrobne spojeve

Natural antimicrobials are an alternative to the use of chemically synthesized preservatives and other technological treatments. They have the advantage of not being rejected by consumers because of their natural origin. However, prior to their usage at a food factory scale, their precise effects on microorganisms have to be known. Nisin, a bacteriocin, and carvacrol and thymol, phenolic compounds present in the essential oil fraction of Oreganum and Thymus plants, have been shown to inhibit growth of different bacteria. This research was conducted to show the effect of a thermal treatment, applied previously, on the growth of B. megaterium cells in a culture medium with and without nisin, carvacrol and thymol. It has been shown that a thermal treatment able to kill 90 % of the spore population of B. megaterium had little effect on the growth of the survivors in nutrient broth at 30 °C. Nisin, in a concentration of 0.05 mM, did not affect greatly the growth of unheated B. megaterium. When the same concentration of nisin was applied to the survivors of the heat treatment, lag phase was further increased and growth rate decreased. Thymol, applied at a concentration of 0.6 mM, increased the lag phase duration almost three times, although it did not change the growth rate. Although carvacrol, at the same concentration (0.6 mM), did reduce the growth rate to half its original value, it did not increase the lag phase duration significantly (only twice), resulting in a quite similar growth curve. The combination of thymol and carvacrol at these high doses (0.6 mM) resulted in a further increase of the lag phase and significant decrease of the growth rate. When carvacrol and/or thymol were combined with a previous thermal treatment (able to kill 90 % of the population), the growth of the survivors was inhibited for at least seven days. Therefore a combination of moderate conditions could be effective to control spoilage by sporeforming bacteria.Prirodna antimikrobna sredstva su alternativa kemijski sintetiziranim konzervansima i drugim tehnološkim postupcima. Njihova je prednost u tome što su zbog svoga prirodnog podrijetla prihvatljivi potrošačima. Prije njihove primjene u prehrambenoj industriji, potrebno je znati kako djeluju na mikroorganizme. Nisin, bakteriocin, te karvakrol i timol, fenolni spojevi prisutni u frakcijama eteričnog ulja biljaka Oreganum i Thymus, inhibiraju rast raznih bakterija. Opisano je istraživanje provedeno da bi se utvrdio učinak prethodno provedene toplinske obrade na rast stanica B. megaterium u podlozi s nisinom, karvakrolom i timolom te bez njih. Pokazalo se da toplinska obrada može usmrtiti 90 % populacije spora B. megaterium, a gotovo nikako ne utječe na rast preživjelih u hranjivoj podlozi pri 30 °C. 22 P.M. PERIAGO et al.: B. megaterium Spore Germination and Growth Inhibition, Food Technol. Biotechnol. 44 (1) 17–23 (2006) Nisin koncentracije od 0,05 mM nije bitno utjecao na rast toplinski neobra|enog B. megaterium. Kada se ista koncentracija nisina primijeni na preživjele spore, produlji se lag faza, a smanji brzina rasta. Timol koncentracije od 0,6 mM produžio je trajanje lag faze skoro 3 puta, a nije promijenio brzinu rasta. Iako je karvakrol iste koncentracije (0,6 mM) smanjio brzinu rasta na polovinu originalne vrijednosti, dužinu lag faze produžio je samo za 2 puta, što je rezultiralo skoro jednakom (0,6 mM) krivuljom rasta. Kombinacijom tih velikih koncentracija timola i karvakrola znatno je produljena lag faza i smanjena brzina rasta. Kada se karvakrol i/ili timol kombiniraju s prethodnom toplinskom obradom (pri čemu je uništeno 90 % populacije), rast preživjelih bio je inhibiran barem 7 dana. Stoga kombinacija jednostavnih uvjeta može biti djelotvorna u kontroli onečišćenja sa sporulirajućim bakterijam

Unusual Manifestation of Toscana Virus Infection, Spain

This study was supported in part by project 05/305, Junta de Andalucía, SpainYe

Serotypes and genotypes of S. pneumoniae isolates from adult invasive disease in Spain: A 5-year prospective surveillance after pediatric PCV13 licensure. The ODIN study

Serotypes/genotypes causing invasive pneumococcal disease (IPD) in adults are determined by vaccina- tion strategies. The aim of this study was to assess the epidemiology of IPD in adults (!18 years) after PCV13 introduction for children: serotypes, clonal complexes, antibiotic non-susceptibility and clinical presentations. We performed a prospective, clinical surveillance of hospitalized culture-confirmed IPDs in adults in nine Spanish hospitals (August 2010-June 2015). A total of 1087 culture-confirmed IPD episodes were included, of which 772 (71.0%) had bacteremic pneumonia (401 complicated/371 uncomplicated pneu- monia), 122 (11.2%) meningitis, 102 (9.4%) non-focal bacteremia, 34 (3.1%) peritonitis and 57 (5.3%) others. The most common serotypes were: 3 (12.7%), 19A (8.5%), 8 (7.7%), 7F (6.3%), 1 (4.2%), 6C (4.2%), 11A (4.2%), 22F (4.2%) and 14 (4.0%). Vaccine types (PCV13 + 6C) caused 49.8% of IPD episodes, with a significant decrease over the 5-year period, and significant decreases in serotypes 6C and 7F. The most common genotypes were: CC180 (8.4%), CC191 (6.0%), and CC53 (5.0%). Vaccine types caused 53.9% (414/768) pneumonia episodes and 58.9% (235/399) complicated pneumo- nia, 53.4% IPD in adults <50 years (143/268), and 54.7% IPD in immunocompetent patients (337/616). Overall non-susceptibility was 25.9% to penicillin (1.1% for parenteral criteria), 24.9% to erythromycin and 2.7% to levofloxacin. Conclusions: Although the percentage of vaccine-types causing IPDs in adults significantly decreased, it remained high. Associations of vaccine types with pneumonia (with complicated pneumonia for specific serotypes), and immunocompetent patients point to the burden of IPD caused by PCV13 serotypes

Multicentre study on the reproducibility of MALDI-TOF MS for nontuberculous mycobacteria identification

The ability of MALDI-TOF for the identification of nontuberculous mycobacteria (NTM) has improved recently thanks to updated databases and optimized protein extraction procedures. Few multicentre studies on the reproducibility of MALDI-TOF have been performed so far, none on mycobacteria. The aim of this study was to evaluate the reproducibility of MALDI-TOF for the identification of NTM in 15 laboratories in 9 European countries. A total of 98 NTM clinical isolates were grown on Lowenstein-Jensen. Biomass was collected in tubes with water and ethanol, anonymized and sent out to the 15 participating laboratories. Isolates were identified using MALDI Biotyper (Bruker Daltonics). Up to 1330 MALDI-TOF identifications were collected in the study. A score >= 1.6 was obtained for 100% of isolates in 5 laboratories (68.2-98.6% in the other). Species-level identification provided by MALDI-TOF was 100% correct in 8 centres and 100% correct to complex-level in 12 laboratories. In most cases, the misidentifications obtained were associated with closely related species. The variability observed for a few isolates could be due to variations in the protein extraction procedure or to MALDI-TOF system status in each centre. In conclusion, MALDI-TOF showed to be a highly reproducible method and suitable for its implementation for NTM identification

Do specific antimicrobial stewardship interventions have an impact on carbapenem resistance in Gram-negative bacilli? A multicentre quasi-experimental ecological study: time-trend analysis and characterization of carbapenemases

CarbaPIRASOA team.[Background] Carbapenem-resistant Gram-negative bacilli (CR-GNB) are among the most threatening microorganisms worldwide and carbapenem use facilitates their spread. Antimicrobial stewardship programmes (ASPs) can help to optimize the use of antibiotics. This study evaluates the impact of a multifaceted educational ASP on carbapenem use and on the epidemiology of CR-GNB.[Methods] We conducted a quasi-experimental, time-series study in seven hospitals, from January 2014 to September 2018. The key intervention was composed of educational interviews promoting the appropriate use of carbapenems. The primary endpoints were carbapenem consumption and incidence density (ID) of CR-GNB. All non-duplicated CR-GNB clinical isolates were tested using phenotypic assays and PCR for the presence of carbapenemases. Joinpoint regression and interrupted time-series analyses were used to determine trends.[Results] A decrease in carbapenem consumption throughout the study period [average quarterly percentage change (AQPC) −1.5%, P < 0.001] and a −8.170 (−16.064 to −0.277) level change following the intervention were observed. The ID of CR-Acinetobacter baumannii decreased (AQPC −3.5%, P = 0.02) and the overall ID of CR-GNB remained stable (AQPC −0.4%, P = 0.52). CR-GNB, CR-Pseudomonas aeruginosa and CR-A. baumannii IDs per hospital correlated with the local consumption of carbapenems. The most prevalent carbapenem resistance mechanisms were OXA-23 for CR-A. baumannii (76.1%), OXA-48 for CR-Klebsiella pneumoniae (66%) and no carbapenemases for CR-P. aeruginosa (91.7%). The epidemiology of carbapenemases was heterogeneous throughout the study, especially for carbapenemase-producing Enterobacteriaceae.[Conclusions] In conclusion, a multifaceted, educational interview-based ASP targeting carbapenem prescribing reduced carbapenem use and the ID of CR-A. baumannii.This work was funded by the Spanish Infectious Diseases and Clinical Microbiology Society (SEIMC).Peer reviewe

Effectiveness of Fosfomycin for the Treatment of Multidrug-Resistant Escherichia coli Bacteremic Urinary Tract Infections

IMPORTANCE The consumption of broad-spectrum drugs has increased as a consequence of the spread of multidrug-resistant (MDR) Escherichia coli. Finding alternatives for these infections is critical, for which some neglected drugs may be an option. OBJECTIVE To determine whether fosfomycin is noninferior to ceftriaxone or meropenem in the targeted treatment of bacteremic urinary tract infections (bUTIs) due to MDR E coli. DESIGN, SETTING, AND PARTICIPANTS This multicenter, randomized, pragmatic, open clinical trial was conducted at 22 Spanish hospitals from June 2014 to December 2018. Eligible participants were adult patients with bacteremic urinary tract infections due to MDR E coli; 161 of 1578 screened patients were randomized and followed up for 60 days. Data were analyzed in May 2021. INTERVENTIONS Patients were randomized 1 to 1 to receive intravenous fosfomycin disodium at 4 g every 6 hours (70 participants) or a comparator (ceftriaxone or meropenem if resistant; 73 participants) with the option to switch to oral fosfomycin trometamol for the fosfomycin group or an active oral drug or pa renteral ertapenem for the comparator group after 4 days. MAIN OUTCOMES AND MEASURES The primary outcome was clinical and microbiological cure (CMC) 5 to 7 days after finalization of treatment; a noninferiority margin of 7% was considered. RESULTS Among 143 patients in the modified intention-to-treat population (median [IQR] age, 72 [62-81] years; 73 [51.0%] women), 48 of 70 patients (68.6%) treated with fosfomycin and 57 of 73 patients (78.1%) treated with comparators reached CMC (risk difference, -9.4 percentage points; 1-sided 95% CI, -21.5 to infinity percentage points; P = .10). While clinical or microbiological failure occurred among 10 patients (14.3%) treated with fosfomycin and 14 patients (19.7%) treated with comparators (risk difference, -5.4 percentage points; 1-sided 95% CI. -infinity to 4.9; percentage points; P = .19), an increased rate of adverse event-related discontinuations occurred with fosfomycin vs comparators (6 discontinuations [8.5%] vs 0 discontinuations; P = .006). In an exploratory analysis among a subset of 38 patients who underwent rectal colonization studies, patients treated with fosfomycin acquired a new ceftriaxone-resistant or meropenem-resistant gram-negative bacteria at a decreased rate compared with patients treated with comparators (0 of 21 patients vs 4 of 17 patients [23.5%]; 1-sided P = .01). CONCLUSIONS AND RELEVANCE This study found that fosfomycin did not demonstrate noninferiority to comparators as targeted treatment of bUTI from MDR E coli; this was due to an increased rate of adverse event-related discontinuations. This finding suggests that fosfomycin may be considered for selected patients with these infections

Treatment with tocilizumab or corticosteroids for COVID-19 patients with hyperinflammatory state: a multicentre cohort study (SAM-COVID-19)

Objectives: The objective of this study was to estimate the association between tocilizumab or corticosteroids and the risk of intubation or death in patients with coronavirus disease 19 (COVID-19) with a hyperinflammatory state according to clinical and laboratory parameters. Methods: A cohort study was performed in 60 Spanish hospitals including 778 patients with COVID-19 and clinical and laboratory data indicative of a hyperinflammatory state. Treatment was mainly with tocilizumab, an intermediate-high dose of corticosteroids (IHDC), a pulse dose of corticosteroids (PDC), combination therapy, or no treatment. Primary outcome was intubation or death; follow-up was 21 days. Propensity score-adjusted estimations using Cox regression (logistic regression if needed) were calculated. Propensity scores were used as confounders, matching variables and for the inverse probability of treatment weights (IPTWs). Results: In all, 88, 117, 78 and 151 patients treated with tocilizumab, IHDC, PDC, and combination therapy, respectively, were compared with 344 untreated patients. The primary endpoint occurred in 10 (11.4%), 27 (23.1%), 12 (15.4%), 40 (25.6%) and 69 (21.1%), respectively. The IPTW-based hazard ratios (odds ratio for combination therapy) for the primary endpoint were 0.32 (95%CI 0.22-0.47; p < 0.001) for tocilizumab, 0.82 (0.71-1.30; p 0.82) for IHDC, 0.61 (0.43-0.86; p 0.006) for PDC, and 1.17 (0.86-1.58; p 0.30) for combination therapy. Other applications of the propensity score provided similar results, but were not significant for PDC. Tocilizumab was also associated with lower hazard of death alone in IPTW analysis (0.07; 0.02-0.17; p < 0.001). Conclusions: Tocilizumab might be useful in COVID-19 patients with a hyperinflammatory state and should be prioritized for randomized trials in this situatio