The present article is an update of the literature on bacterial pathogens. Recognizing the interest and scientific and public health importance of infections produced by bacterial pathogens with new virulence mechanisms and/or new mechanisms of resistance to antimicrobial agents, a multidisciplinary group of Spanish physicians and microbiologists organized a joint session and revised the most important papers produced in the field during 2006. Each article was analyzed and discussed by one of the members of the panel. This paper focus on a variety of diseases that pose major clinical and public health challenges today; and include infections produced by community-acquired methicillin-resistant Staphylococcus aureus and S. aureus small colony variants, infections produced by multiply resistant coagulase-negative staphylococci, pneumococcal infections, human listeriosis, meningococcal disease, Haemophilus influenzae, pertussis, Escherichia coli, ESBL-producing organisms, and infections due to non-fermenters. After a review of the state of the art, papers selected in this field are discussed.
El presente artículo recoge una actualización bibliográfica de patógenos bacterianos. Dado el interés científico y la importancia que tienen para la salud pública las infecciones producidas por patógenos bacterianos con nuevos mecanismos de virulencia y/o nuevos mecanismos de resistencia a los antimicrobianos, un grupo multidisciplinario de microbiólogos y clínicos españoles, con experiencia en enfermedades infecciosas, organizó una reunión en la que se revisaron los artículos más importantes en este campo, publicados en 2006.El contenido de cada uno de los artículos seleccionados fue expuesto y discutido por uno de los miembros del grupo. Este artículo revisa algunas de las enfermedades infecciosas bacterianas que suponen hoy en día algunos de los principales retos para la salud pública e incluye las infecciones producidas por Staphylococcus aureus resistente a meticilina de adquisición comunitaria, las producidas por variantes de colonia pequeña de S. aureus, las relacionadas con estafilococos coagulasa negativa multirresistentes, la infección neumocócica, la listeriosis humana, la infección meningocócica, la tos ferina, las infecciones por Haemophilus influenzae, la diseminación de las bacterias productoras de BLEE, y las infecciones por bacilos gramnegativos no fermentadores. Tras la revisión de la situación actual, se discuten y comentan diferentes artículos relacionados con estos aspectos.

BACKGROUND: This analysis investigated longitudinal changes in meningococcal carriage in adolescents in South Australia over 4 years.
METHODS: Data from the \"B Part of It\" study, which included a state-wide cluster randomized controlled trial in secondary-school students (n = 34,489 in 2017 and 2018) and serial cross-sectional studies in school leavers aged 17-25 years (n = 4028 in 2019-2020). Individuals had oropharyngeal swabs collected annually. This study included two unique cohorts: (1) individuals enrolled in 2019, with three consecutive annual swabs taken in 2017, 2018 and 2019; and (2) individuals enrolled in 2020, with swabs taken in 2017, 2018, and 2020. Disease-associated N. meningitidis genogroups were identified using PCR and whole genome sequencing. Univariate analysis identified risk factors for recurrent carriage (≥2).
RESULTS: Among school leavers, 50 (1.7%, total n = 2980) had carriage detected at successive visits. In participants with meningococcal carriage at successive visits, 38/50 (76.0%) had the same genogroup detected by porA PCR. Of those, 19 had the same MLST type and demonstrated minimal variation, indicating they most likely had sustained carriage of the same isolate (range 226 to 490 days, mean duration 352 [SD 51] days). In the 2019 school leaver cohort, 6.7% acquired carriage in their first year out of school compared to 3.3% in their final school year. Compared to single carriage detection, recurrent carriage was potentially more likely in older adolescents (16 compared to ≤15 years; OR = 1.97 (95%CI 1.0, 3.86); p = 0.048).
CONCLUSIONS: Whilst carriage is typically transient, some adolescents/young adults may have persistent carriage and are likely to be an important group in the transmission of meningococci.

Paroxysmal nocturnal haemoglobinuria (PNH) is a rare acquired haematopoietic stem cell disease characterized by complement-mediated intravascular hemolysis, thrombosis, and bone marrow failure. Eculizumab and ravulizumab are anti-C5 monoclonal antibodies that reduce hemolysis, anaemia and thrombotic risk, but are associated with increased risk of infection with encapsulated bacteria, including Neisseria meningitidis. We report a case of life-threatening infection by non-groupable Neisseria meningitidis in a young PNH patient treated with ravulizumab. Despite prompt admission to the intensive care unit, microbe isolation was delayed due to the negativity of capsular antigens, and the patient required intubation, dialysis, and transfusion support for pancytopenia. Notably, PNH disease activity remained controlled and no additional anti-C5 doses were administered. Increasing awareness regarding septic risk in PNH patients on complement inhibitors despite vaccinations is pivotal. A warning about serotypes generally not pathogenetic and not covered by vaccination, such as non-capsulated forms, is emerging.

Meningitis and meningococcal septicemia are potentially life-threatening illnesses; young people in educational institutions have been repeatedly exposed to outbreaks of meningococcal infections. Since invasive meningococcal disease is preceded by pharyngeal carriage of Neisseria meningitidis, ascertaining the prevalence of meningococcal carriage in this population is of utmost importance. The aim of this study was to determine the rate of meningococcal carriage in students of Shahid Beheshti University of Medical Sciences. This cross-sectional study was conducted on pharyngeal swab specimens of 251 healthy asymptomatic students from November 2019 for one year. A questionnaire was used to find correlation between isolation of Neisseria spp. and the place of residence, number of roommates, antibiotic use in the last month, and smoking. One sample from each student was used for culture on general and selective culture media for Neisseria spp. Polymerase chain reaction was used for the final diagnosis of Neisseria meningitidis. Participants in the study included 222 medical students (88.4%), 23 nursing students (9.2%) and 6 radiology students (2.4%). Mean (IQR1) age of students was 23 years, 134 students were female, (53.4%); 234 students were single, (93.2%). 92 students (36.7%) lived in dormitories. Neisseria were isolated from 18 specimens (7.2%), of which 11 (4.4%) were pigmented bacteria. PCR assay did not detect Neisseria meningitidis in any of the samples. This study showed that meningococcal bacteria were not detected in any of the oropharyngeal specimens from students participating in the study during the one-year study period.

The identification of an appropriate animal model for use in the development of meningococcal vaccines has been a challenge as humans are the only natural host for Neisseria meningitidis. Small animal models have been developed and are widely used to study the efficacy or immunogenicity of vaccine formulations generated against various diseases. Here, we describe the development and optimization of a mouse model for assessing the immunogenicity of candidate tetravalent meningococcal polysaccharide (MenACYW-TT) protein conjugate vaccines. Three inbred (BALB/c [H-2d], C3H/HeN [H-2k], or C57BL/6 [H-2b]) and one outbred (ICR [H-2g7]) mouse strains were assessed using serial two-fold dose dilutions (from 2 µg to 0.03125 µg per dose of polysaccharide for each serogroup) of candidate meningococcal conjugate vaccines. Groups of 10 mice received two doses of the candidate vaccine 14 days apart with serum samples obtained 14 days after the last dose for the evaluation of serogroup-specific anti-polysaccharide IgG by ELISA and bactericidal antibody by serum bactericidal assay (SBA). C3H/HeN and ICR mice had a more dose-dependent antibody response to all four serogroups than BALB/c and C57Bl/6 mice. In general, ICR mice had the greatest antibody dose-response range (both anti-polysaccharide IgG and bactericidal antibodies) to all four serogroups and were chosen as the model of choice. The 0.25 µg per serogroup dose was chosen as optimal since this was in the dynamic range of the serogroup-specific dose-response curves in most of the mouse strains evaluated. We demonstrate that the optimized mouse immunogenicity model is sufficiently sensitive to differentiate between conjugated polysaccharides, against unconjugated free polysaccharides and, to degradation of the vaccine formulations. Following optimization, this optimized mouse immunogenicity model has been used to assess the impact of different conjugation chemistries on immunogenicity, and to screen and stratify various candidate meningococcal conjugate vaccines to identify those with the most desirable profile to progress to clinical trials.

UNASSIGNED: Descriptive analysis of meningitis outbreak in Jaman North districts of Brong Ahafo Region.
UNASSIGNED: Descriptive secondary data analysis.
UNASSIGNED: records of meningitis cases were extracted from case-based forms and line list.
UNASSIGNED: The source and pattern of outbreak.
UNASSIGNED: A total of 367 suspected cases with 44 confirmed were recorded from Jaman North during the period of January to March 2016. The mean age of those affected was 58 ± 13 years. The case fatality rate was 0.82% and the proportion of males to females was 1:1.3 (160/207). The age group most affected was 15-29 years (54.7%) and the least was 45-49 years (3.0%). Streptococcus pneumoniae formed 77.3% of confirmed cases whilst Neisseria meningitides was 20.5%. Cases with Neisseria meningitides came from a border town in La Cote d\'Ivoire.
UNASSIGNED: A protracted propagated meningitis outbreak occurred; and the predominant bacteria strain among confirmed cases was Streptococcus pneumoniae. Cases were mainly females and the most vulnerable group were people aged 15-29 years.
UNASSIGNED: This work was funded by the authors. Author BKD was sponsored under CDC (Frontline FETP)-CDC CoAg 6NU2GGH001876.

The four-component meningococcal serogroup B vaccine (4CMenB) contains antigens present in the majority of meningococci causing invasive meningococcal disease (IMD) and may potentially offer protection against strains belonging to non-B serogroups.This study aimed to evaluate the ability of 4CMenB-induced antibodies to kill, in a human serum bactericidal assay (hSBA), non-B meningococci belonging to the main genotypes responsible for IMD in Italy.Meningococci, collected between 2015 and 2017, was characterized for PorA, FetA and sequence type, and for clonal complex. Twenty non-B isolates, representative of the most frequent genotypes, were molecularly characterized for 4CMenB antigens and tested in hSBA with sera from 4CMenB-vaccinated infants and adolescents.Among twenty isolates, eleven were serogroup C, five were Y, two W and two X. All isolates contained genes encoding for fHbp and NHBA antigens and four harbored the NadA full-length encoding gene. Positive hSBA titers were obtained against all serogroup W, X and Y isolates and against five serogroup C isolates.These data show that the 4CMenB vaccine can induce bactericidal antibodies against genetically representative meningococcal W, Y and X strains from Italy. For serogroup C, different susceptibilities to killing were observed for strains with similar antigenic repertoires.

In silico studies are attracting considerable interest due to their ability to understand protein-ligand interactions at the atomic level. The main principal tools of this in silico analyses are molecular docking and molecular dynamic (MD) simulation. This paper examines how can natural compounds that are derived from Salviae miltiorrhizae to block Neisseria adhesion A Regulatory protein (NadR). In molecular docking analysis, only four compounds were found in higher binding affinity with NadR among 10 candidates (tanshinol B, tanshinol A, lithospermic acid and tournefolal were -7.61, -7.56, -8.22 and -7.81 kcal/mol, respectively, compared to -7.23 kcal/mol of native ligand). Absorption, distribution, metabolism, excretion (ADME) and toxicity properties, medicinal chemistry profile, and physicochemical features were displayed that tournefolal contains good properties to work as a safe and good anti-adhesive drug. Therefore, the complexes of these four ligands with NadR protein were subjected to 100 ns of MD simulation. RMSD, RMSF, RG and hydrogen bonding exhibited that tournefolal showed stable binding affinity and molecular interaction with NadR protein. In light of these results, there is now a need to conduct much more in vitro and in vivo studies about the efficacy of tournefolal.Communicated by Ramaswamy H. Sarma.

Infective endocarditis caused by Neisseria meningitidis (NM) is a very rare manifestation of invasive meningococcal disease with only a few cases described in the literature. We report a case of a native mitral valve endocarditis caused by NM in a 61-year-old female without meningitis. Our case highlights the importance of considering NM as one of the causative organisms of infective endocarditis, even in the absence of meningitis. Even though the cases of NM endocarditis have drastically decreased with the advent of antibacterials, NM should always be considered in the differential diagnosis in certain high-risk groups, like diabetics, polysubstance abusers, and elderly individuals. The prognosis is good with early appropriate antibiotic treatment with or without surgery.

Chronic meningococcemia is a rare manifestation of meningococcal disease, characterized by a period of more than one week of intermittent or continuous fever, arthralgia and skin lesions without meningitis. It can occur both in previously healthy and immunocompromised patients. The gold standard for the diagnosis is culture isolation of Neisseria meningitidis in sterile material. We describe a case of a vertically HIV-infected adolescent with chronic meningococcal disease.