Quantitative Risk Assessment of Bacillus cereus Growth during the Warming of Thawed Pasteurized Human Banked Milk Using a Predictive Mathematical Model.

Bacillus cereus is relatively resistant to pasteurization. We assessed the risk of B. cereus growth during warming and subsequent storage of pasteurized banked milk (PBM) in the warmed state using a predictive mathematical model. Holder pasteurization followed by storage below -18 °C was used. Temperature maps, water activity values, and B. cereus growth in artificially inoculated PBM were obtained during a simulation of manipulation of PBM after its release from a Human Milk Bank. As a real risk level, we chose a B. cereus concentration of 100 CFU/mL; the risk was assessed for three cases: 1. For an immediate post-pasteurization B. cereus concentration below 1 CFU/mL (level of detection); 2. For a B. cereus concentration of 10 CFU/mL, which is allowed in some countries; 3. For a B. cereus concentration of 50 CFU/mL, which is approved for milk formulas. In the first and second cases, no risk was detected after 1 h of storage in the warmed state, while after 2 h of storage, B. cereus concentrations of 102 CFU/mL were occasionally encountered. In the third case, exceeding the B. cereus concentration of 102 CFU/mL could be regularly expected after 2 h of storage. Based on these results, we recommend that post-pasteurization bacteriological analysis be performed as recommended by the European Milk Bank Association (EMBA) and using warmed PBM within 1 h after warming (no exceptions).

Bacillus cereus as a Major Cause of Discarded Pasteurized Human Banked Milk: A Single Human Milk Bank Experience.

A systematic study, performed from 2017-2020 looked at the rate of positive post-pasteurization B. cereus findings, the quantity of B. cereus in pasteurized banked human milk (PBM), and the rate of B. cereus toxicogenic isolates from PBM. During the study period, 6815.71 L (30,943 tested bottles) of PBM were tested, with an average amount per year of 1703.93 L (7736 tested bottles). The PBM discard rate per year due to bacterial contamination varied between 8.7-10.0% and contamination with B. cereus was the most frequent reason. The total number of B. cereus positive tests was 2739 and the proportion of its positivity from all positive tests was between 56.7-66.6%. The prevalence of B. cereus positive tests rose significantly in the summer months. The production of enterotoxin was found in 3 of the 20 tested samples (15.0%). The B. cereus CFU-quantities in the PBM were below 10 CFU/mL in 80% of cases (16 of 20 samples tested). The quantitative data can be used in the risk assessment of cold storage of PBM at temperatures above zero and manipulation of PBM prior to its administration.

Effect of Restriction of Fluoroquinolone Antibiotics on Clostridioides difficile Infections in the University Hospital Hradec Králové.

Clostridioides difficile is the most common pathogen responsible for hospital-acquired diarrhea. This complication of antibiotic treatment mainly endangers the health of elder patients. Preventing the development of C. difficile infections (CDI) is still a challenge that needs to be addressed. In our study, the results of 872 C. difficile positive stool samples were used to describe the epidemiological situation affected by a change in the prescription of fluoroquinolone antibiotics. In a total, 93 of strains were typed by polymerase chain reaction (PCR) and capillary gel electrophoresis. Between years 2014 and 2018 the decline in the fluoroquinolones consumption was 69.3 defined daily dose (DDD) per 1000 patient-days (from 103.3 to 34.0), in same period CDI incidence declined by 1.3 cases per 10,000 patient-bed days (from 5.6 to 4.3). Results of epidemiologic and statistical analysis shows that decline in fluoroquinolones consumption has significant influence on CDI incidence and prevalence of hypervirulent strains. In the University Hospital Hradec Králové properly managed antibiotic stewardship policy has reduced CDI incidence by 23.2% and lowered rate of hypervirulent ribotypes 001 and 176.

The wide-spectrum antimicrobial effect of novel N-alkyl monoquaternary ammonium salts and their mixtures; the QSAR study against bacteria.

Quaternary ammonium salts (QASs) have been widely used for disinfection purposes because of their low price, high efficacy and low human toxicity for decades. However, precise mechanisms of action nor the powerful versatile agent against all antimicrobial species are known. In this study we have prepared 43 novel N-alkyl monoquaternary ammonium salts including 7 N,N-dialkyl monoquaternary ammonium salts differing bearing alkyl chain either of 12, 14 or 16 carbons. Together with 15 already published QASs we have studied the antimicrobial efficacy of all water-soluble compounds together with standard benzalkonium salts against Gram-positive (G+) and Gram-negative (G-) bacteria, anaerobic spore-forming Cl. difficile, yeasts, filamentous fungi and enveloped Varicella zoster virus (VZV). To address the mechanism of action, lipophilicity seems to be a key parameter which determines antimicrobial efficacy, however, exceptions are likely to occur and therefore QSAR analysis on the efficacy against G+ and G- bacteria was applied. We showed that antibacterial activity is higher when the molecule is larger, more lipophilic, less polar, and contains fewer oxygen atoms, fewer methyl groups bound to heteroatoms or fewer hydrogen atoms bound to polarized carbon atoms. In addition, from an application point of view, we have formulated mixtures, on the basis of obtained efficiency of individual compounds, in order to receive wide-spectrum agent. All formulated mixtures completely eradicated tested G+ and G- strains, including the multidrug-resistant P. aeruginosa as well as in case of yeasts. However, effect on A. fumigatus, Cl. difficile and VZV the exposition towards mixture resulted in significant reduction only. Finally, 3 out of 4 formulated mixtures were safer than reference commercial agent based on benzalkonium salts only in the skin irritation test using reconstructed human epidermidis.

Antibiotic Resistance in Nosocomial Bacteria Isolated from Infected Wounds of Hospitalized Patients in Czech Republic.

Hospitalized patients with wounds face an increased risk of infection with multi-drug-resistant nosocomial bacteria. In this study, samples from almost 10,000 patients from big hospitals in Czech Republic with infected wounds were analyzed for the presence of bacterial pathogens. In 7693 patients (78.8%), bacterial etiological agents were identified. Members of the Enterobacterales (37.1%) and Staphyloccus aureus (21.1%) were the most prevalent pathogens. Staphyloccus aureus showed methicillin resistance in 8.6%. Almost half of the Klebsiella pneumoniae isolates were ESBL-positive and 25.6% of the Enterobacter spp. isolates were AmpC-positive. The third most prevalent Pseudomonas aeruginosa showed resistance to 19-32% of the antipseudomonal antibiotics tested. Based on the results, amoxicillin/clavulanic acid, ampicillin/sulbactam or piperacillin/tazobactam combined with gentamicin can be recommended for antibiotic treatment of infected wounds. Once the etiological agent is identified, the therapy should be adjusted according to the species and its resistance.

Characterization of KPC-Encoding Plasmids from Enterobacteriaceae Isolated in a Czech Hospital.

Ten Enterobacteriaceae isolates collected in a Czech hospital carried blaKPC-positive plasmids of different sizes (∼30, ∼45, and ∼80 kb). Sequencing revealed three types of plasmids (A to C) with the Tn4401a transposon. Type A plasmids comprised an IncR backbone and a KPC-2-encoding multidrug resistance (MDR) region. Type B plasmids were derivatives of type A plasmids carrying an IncN3-like segment, while type C plasmids were IncP6 plasmids sharing the same KPC-2-encoding MDR region with type A and B plasmids.

[Outbreak of SARG in a neonatal intensive care unit].

The article provides information on an outbreak of infection with a strain of Staphylococcus aureus resistant to gentamicin (SARG) and a hyperproducer of enterotoxins A and D at a neonatal intensive care unit of the University Hospital in Hradec Králové. A retrospective investigation was carried out that provided an overview of the presence of the SARG strain in the patients, staff and hospital environment. Subsequently, strict infection precautions were implemented and the importance of rational antimicrobial therapy was emphasized.

Immunogenicity and safety of quadrivalent versus trivalent inactivated influenza vaccine: a randomized, controlled trial in adults.

BACKGROUND: Two phylogenetic lineages of influenza B virus coexist and circulate in the human population (B/Yamagata and B/Victoria) but only one B-strain is included in each seasonal vaccine. Mismatch regularly occurs between the recommended and circulating B-strain. Inclusion of both lineages in vaccines may offer better protection against influenza. METHODS: This study (NCT00714285) assessed the immunogenicity and safety of two candidate quadrivalent influenza vaccines (QIV) containing two A- and two B-strains (one from each lineage) in adults (18-60 years). Subjects were randomized and stratified by age to receive either QIV (non-adjuvanted or low-dose adjuvanted [LD QIV-AS]) or trivalent influenza vaccine (TIV, non-adjuvanted or low-dose adjuvanted [LD TIV-AS]), N = 105 in all treatment groups. The study evaluated the statistical non-inferiority of the immunological response elicited by QIV and LD QIV-AS versus TIV and LD TIV-AS and the statistical superiority of the response elicited by the quadrivalent vaccines against the B-strain (B/Jiangsu) not included in the TIV. RESULTS: Pre-defined non-inferiority and superiority criteria were reached for both QIVs compared to the TIVs. On Day 21 in all vaccine groups SCRs were ≥54.8%, SPRs ≥88.5% and SCFs ≥5.4 for the A strains and B strain included in all vaccines (B/Malaysia). This fulfilled the European (CHMP) and the US (CBER) licensing criteria for the assessment of influenza vaccines in adults (CHMP criteria: SCR > 40%, SPR > 70%, SCF > 2; CBER criteria: LL of 95% CI for SPR ≥ 70% or SCR ≥ 40%). Only the QIVs met the CHMP and CBER criteria for the B/Jiangsu strain. In the QIV and LD-QIV-AS groups, the SCFs were 9.1 and 8.1, respectively and the SPRs were 98.1% and 95.2%, whereas for the TIV and LD-TIV-AS groups, the SCFs were 2.3 and 2.5, respectively, and the SPRs were 75.0% and 63.8%, with the LLs of the 95% CI <70% for SPR and <40% for SCR. CONCLUSIONS: Addition of a fourth strain did not impact the immune response elicited by the three original strains contained in the TIV. A clear immunological benefit was seen with the QIV formulation for the second B-strain, indicating that quadrivalent vaccines could provide broader protection against influenza. TRIAL REGISTRATION: ClinicalTrials.gov: NCT00714285.

Comparison of long-term (10 years) immunogenicity of two- and three-dose regimens of a combined hepatitis A and B vaccine in adolescents.

300 adolescents aged 12-15 years were randomised (1:1) into two groups to compare the long-term (10 years) immunogenicity profile of two doses of an Adult formulation [Group HAB_2D: 150; 0-6 months] vs. three doses of a Paediatric formulation [Group HAB_3D: 150; 0-1-6 months] of a combined hepatitis A and B (HAB) vaccine. At Year 10, anti-HAV seropositivity rate was 100% in both groups, while 85.9% and 85.1% subjects in the HAB_2D and HAB_3D groups, respectively, had anti-HBs antibody concentrations > or =10 mIU/mL. The anti-HAV antibody GMCs (HAB_2D: 429.3 mIU/mL; HAB_3D: 335.5 mIU/mL) and anti-HBs antibody GMCs (HAB_2D: 50.6 mIU/mL; HAB_3D: 60.1 mIU/mL) were similar in both groups. No vaccine-related serious adverse events were reported. Hence, with respect to long-term antibody persistence, the two-dose schedule of the combined HAB vaccine Adult formulation is an effective alternative to the conventional three-dose schedule of the Paediatric formulation in adolescents.

Safety and immunogenicity of an investigational adjuvanted hepatitis B vaccine (HB-AS02V) in healthy adults.

HB-AS02 is an investigational adjuvanted hepatitis B virus (HBV) vaccine for potential use in patients with renal insufficiency and other immunocompromized individuals. In this Phase III lot-to-lot consistency study, 450 healthy adult volunteers who had not previously been vaccinated against HBV were randomized to one of three production lots of HB-AS02 at 0 and 1 month and followed until one month after the last vaccine dose. Lot-to-lot consistency was established. High seroprotection rates were already achieved after the first vaccine dose (75.9%). All subjects were seroprotected (anti-HBs antibody concentrations ≥10 mIU/ml) after two doses, with all but one subject achieving anti-HBs antibody concentrations ≥100 mIU/ml (99.7%). Geometric mean anti-HBs antibody concentration was 4594.5 mIU/ml. Local and general symptoms were reported after 80.7% and 45.5% of doses, respectively. However, these were mainly of mild or moderate severity and no subject withdrew from the study due to adverse events.

A phase III, randomized, open-label study to assess the tolerability and immunogenicity of an H5N1 influenza vaccine administered to healthy adults with a 1-, 2-, 3-, or 6-week interval between first and second doses.

BACKGROUND: Preparedness for an H5N1 influenza pre-pandemic requires effective and well-tolerated emergency vaccination strategies that provide both pandemic strain-specific and heterologous protection. OBJECTIVES: This was a pivotal study for the regulatory approval process for a candidate MF59-adjuvanted H5N1 vaccine. Its goals were to identify the preferred primary 2-dose vaccination schedule in adults and to assess whether the vaccine met European Committee for Medicinal Products for Human Use (CHMP) licensure criteria. METHODS: Healthy volunteers aged 18 to 60 years received 1 of 4 randomized schedules in which the 2 doses of vaccine were separated by a 1-, 2-, 3-, or 6-week interval. Three blood samples (~20 mL(-1)) were obtained from each subject: the first sample, immediately before administration of the first dose of vaccine; the second, immediately before administration of the second dose; and the third, 21 days after administration of the second dose. Hemagglutination inhibition (HI), microneutralization (MN), and single radial hemolysis (SRH) were assayed after each dose. Immunogenicity was assessed based on the CHMP licensure criteria for annual influenza vaccines (number of seroconversions or significant increase in HI titer >40%; mean geometric increase >2.5; and proportion of subjects achieving an HI titer ≥40 or SRH titer >25 mm(2) should be >70% [seroprotection]). Subjects recorded all adverse events occurring within 7 days of vaccine administration; information on any serious adverse events was collected throughout the study (duration, 202 days). RESULTS: All study participants (N = 240) were white, with a mean age of 33 years and a mean body mass index of 24.6 kg/m(2). Equal numbers of men and women were assigned to each vaccination schedule. The CHMP criterion for seroprotection was achieved when the 2 doses of vaccine were separated by 2 (76%), 3 (72%), and 6 (79%) weeks; similar results were obtained on MN and SRH analysis. On the SRH analysis, the candidate vaccine showed a heterologous immune response to the H5N1/turkey/Turkey/1/05 (NIBRG-23; clade 2) influenza antigen. The vaccine met 2 of the 3 European licensure criteria, with seroconversion rates of 69% and 65% in the groups assigned to a 2- and 3-week interval between doses, respectively, and geometric mean ratios of 4.3 and 4.5. There were no serious adverse events related to vaccination. The most common adverse events reported within 7 days of the first and second doses of vaccine were mild to moderate injection-site pain (63%-73% and 34%-48%, respectively) and fatigue (25%-30% and 13%-24%). CONCLUSIONS: Two 7.5-µg doses of MF59-adjuvanted H5N1 influenza vaccine given 2, 3, or 6 weeks apart afforded H5N1-specific immunity and met the CHMP licensure criterion for seroprotection in these healthy volunteers. Clinically relevant levels of heterologous immunity were observed when the 2 doses of vaccine were administered either 2 or 3 weeks apart; however, the licensure criterion for seroprotection was not met in this case.