Genomic characterization of Haemophilus influenzae harbouring an exogenous resistance gene.

Introduction. Reports of ß-lactamase-producing Haemophilus influenzae are increasing worldwide.Aim. This study aimed to elucidate the molecular characteristics and evolution of ß-lactamase-producing H. influenzae.Methodology. A total of 159 clinical isolates were characterized using multi-locus sequence typing. Antimicrobial resistance genes and integrative and conjugative element (ICE) types were identified through PCR and DNA sequencing. The genetic structure of ICE was further investigated using whole-genome sequencing.Results. Out of 159 clinical isolates, 20.8% (n=33) were ß-lactamase producers. Thirteen sequence types (STs) were identified. ST 103, 155, 165 and 388 have been identified in previous studies, suggesting that strains with these STs tend to acquire the ß-lactamase gene bla TEM-1. Among ß-lactamase producers, 66.7% (n=22) of bla TEM-1 were located on ICE. The ICEs could be classified into two groups based on their sequence (types I and II). Among these strains, 2017-Y3 harboured a macrolide resistance gene, mef (A/E), in ICE. A comparative analysis of the ICE region of this strain and those from other countries suggested that each isolate was derived from ICE type I or II. These regions, including mef (A/E), were similar to those of Tn6822, which is commonly found in Streptococcus.Conclusions. This study revealed several STs associated with the acquisition of ß-lactamase genes on ICEs. Additionally, ICE evolution involved the acquisition of exogenous genes. The accumulation of resistance genes in ICE raises concerns regarding the emergence of multidrug-resistant H. influenzae.

Whole-genome sequencing of non-typeable Haemophilus influenzae isolated from a tertiary care hospital in Surabaya, Indonesia.

BACKGROUND: Haemophilus influenzae causes life-threatening invasive diseases such as septicaemia and meningitis. Reports on circulating H. influenzae causing invasive disease in lower-middle income settings, including Indonesia, are lacking. This study describes the serotype distributions and whole-genome sequence (WGS) data of H. influenzae isolated from hospitalized patients at Soetomo Hospital, Surabaya, Indonesia. METHODS: H. influenzae isolates were isolated from blood and pleural fluid specimens and identified using culture-based and molecular methods, followed by serotyping and WGS using RT‒PCR and Illumina MiSeq, respectively. Sequencing reads were assembled, and further analyses were undertaken to determine the genomic content and reconstruct the phylogeny. A second dataset consisting of publicly available H. influenzae genomes was curated to conduct phylogenetic analyses of isolates in this study in the context of globally circulating isolates. RESULTS: Ten H. influenzae isolates from hospitalized patients were collected, and septicaemia was the most common diagnosis (n=8). RT‒PCR and WGS were performed to determine whether all the isolates were nontypeable H. influenzae (NTHi). There were four newly identified STs distributed across the two main clusters. A total of 91 out of 126 virulence factor (VF)-related genes in Haemophilus sp. were detected in at least one isolate. Further evaluation incorporating a global collection of H. influenzae genomes confirmed the diverse population structure of NTHi in this study. CONCLUSION: This study showed that all H. influenzae recovered from invasive disease patients were nonvaccine-preventable NTHi isolates. The inclusion of WGS revealed four novel STs and the possession of key VF-associated genes.

A prospective, observational, multi-center, post-marketing safety surveillance study of the GSK combined vaccine against diphtheria, tetanus, pertussis, poliomyelitis, and Haemophilus influenzae type b invasive infections (DTaP-IPV/Hib) in South Korean infants.

In South Korea, a combined vaccine against diphtheria, tetanus, pertussis, poliomyelitis, and Haemophilus influenzae type b invasive infections (DTaP-IPV/Hib) is available since 2018 for vaccination of infants from the age of 2 months. This prospective, observational, non-comparative, post-marketing study evaluated the real-world safety of DTaP-IPV/Hib primary vaccination in eligible South Korean infants from the age of 2 months between 2018 and 2022. Infants were followed up for 30 days after each vaccine dose to assess the proportion of infants experiencing any adverse event (AE), including adverse drug reactions (ADRs), unexpected AEs, and serious AEs/serious ADRs (SAEs/SADRs). Of 660 infants vaccinated during the study period, 646 were included in the total safety cohort. A total of 194 AEs were reported in 143 (22.1%) infants; 158 AEs occurred after the first dose in 130 (20.1%) infants, 21 after the second dose in 20 (13.4%) infants, and 11 after the third dose in ten (8.1%) infants. The most frequent AEs by Medical Dictionary for Regulatory Activities Preferred Terms terminology were pyrexia (13.3%), injection site swelling (5.1%), and irritability (1.7%). Most of the AEs were mild, resolved without a medical visit, and were classified as possibly related to vaccination. The incidence proportions of ADRs, unexpected AEs, and SAEs/SADRs were 19.4%, 4.3%, and 0.9%, respectively. All SAEs/SADRs resolved after hospitalization or emergency room visit, and one event was possibly related to vaccination. These results are in line with the approved label and other national/international studies, confirming the acceptable safety profile of DTaP-IPV/Hib in the South Korean pediatric population.

In South Korea, a vaccine to help protect infants against five childhood diseases (diphtheria, tetanus, whooping cough, poliomyelitis, and Haemophilus influenzae type b invasive infections) called DTaP-IPV/Hib vaccine, has been available since 2018. As required by Korean regulation, this study aimed to confirm that DTaP-IPV/Hib was well tolerated by South Korean infants during its first 4 years of use in the country (2018­2022). This study followed 646 healthy infants aged 2­3 months who received up to three vaccine doses with 2-month intervals between doses, according to the Korean vaccination recommendations. The infants were followed for 30 days after each vaccination to evaluate how often adverse events (AEs) occurred during that period. An AE was defined as any untoward medical event after exposure to the vaccine, but not necessarily caused by that same vaccine. Overall, 194 AEs occurred during the study. On average, at least one AE was reported in 22% of infants within 30 days following vaccination. These AEs were mostly fever (body temperature >38.0°C), swelling at vaccine injection site, and irritability. A serious AE (SAE) was reported for 0.9% of infants. The infants always recovered from these SAEs after hospitalization or emergency room visit. The reported AEs are indicated in the vaccine package insert, meaning they were possibly expected to occur after vaccination. This study therefore confirms the acceptable safety profile of DTaP-IPV/Hib when given to South Korean infants in accordance with local prescribing recommendations and as part of routine childhood immunization.

Infectious Coryza in Pennsylvania.

Infectious coryza (IC) is a respiratory disease of chickens, including pullets, layers, and broilers, caused by the bacteria Avibacterium paragallinarum (AP), which was previously known as Hemophilus gallinarum. IC classically causes production decreases and mortality in chickens, frequently paired with swelling of the sinuses, mucoid nasal discharge, and respiratory rales. Although IC is considered an endemic disease of chickens in California, it has been unusual to rare in commercial chickens in Pennsylvania. The last reported IC case in Pennsylvania was in 2002, involving broiler breeders. However, between December 2018 and December 2019, 68 farms were affected by IC in Pennsylvania, involving approximately 14 million birds. Several farms had multiple flocks affected. Most affected farms housed layer chickens (37/68), but a smaller number of broiler farms, pullet farms, and layer breeder farms have been affected. Ages of affected birds and duration of disease were variable between flocks, as were the severity of clinical signs, pathologic lesions, and rates of mortality. PCR testing has greatly aided and sped diagnostic efforts in addition to traditional bacterial culture. In eight layer cases and five broiler cases, bacterial culture of the sinus or choanal cleft proved unrewarding, whereas culture of trachea, air sacs, lungs, heart, or liver were diagnostic. Although cases of IC in commercial Pennsylvania poultry continue, they have been greatly reduced because of implementation of a successful vaccination program. In this case series report we detail epidemiologic, clinical, and pathologic aspects of this outbreak and discuss vaccination as a control measure of IC in the state of Pennsylvania.

Coriza infecciosa en Pensilvania. La coriza infecciosa (CI) es una enfermedad respiratoria de las gallinas, incluyendo pollas de reemplazo, gallinas de postura y pollo de engorde, causada por la bacteria Avibacterium paragallinarum (AP), que anteriormente era conocida como Hemophilus gallinarum. Clásicamente, la coriza infecciosa causa disminución en la producción y aumento de la mortalidad en los pollos, frecuentemente es acompañada de inflamación de los senos nasales, secreción nasal mucoide y estertores respiratorios. Aunque la coriza infecciosa se considera una enfermedad endémica en la avicultura en California, ha sido inusual o esporádica en las aves comerciales de Pensilvania. El último caso notificado de coriza infecciosa en Pensilvania ocurrió en el 2002 y afectó a reproductoras pesadas. Sin embargo, entre diciembre del 2018 y diciembre del 2019, 68 granjas se vieron afectadas por esta enfermedad en Pensilvania, lo que afectó a aproximadamente 14 millones de aves. Varias granjas tuvieron múltiples parvadas afectadas. La mayor'ia de las granjas afectadas albergaban gallinas de postura (37/68), pero un número menor de granjas de pollos de engorde, de pollas de reemplazo y de reproductoras de aves de postura se han visto afectadas. Las edades de las aves afectadas y la duración de la enfermedad variaron entre parvadas, al igual que la severidad de los signos cl'inicos, las lesiones patológicas y las tasas de mortalidad. Las pruebas de PCR han ayudado acelerado enormemente los esfuerzos de diagnóstico además del cultivo bacteriano tradicional. En ocho casos de ponedoras y cinco de pollos de engorde, el cultivo bacteriano de senos respiratorios o de la hendidura coanal resultó infructuoso, mientras que el cultivo de tráquea, alvéolos, pulmones, corazón o h'igado fueron de utilidad diagnóstica. Aunque la presentación de casos de coriza infecciosa en aves comerciales de Pensilvania continúa, se han reducido considerablemente gracias a la implementación de un programa de vacunación exitoso. En esta serie de reportes de casos, se detallan los aspectos epizootiológicos, cl'inicos y patológicos de este brote y se analiza la vacunación como medida de control contra la coriza infecciosa en el estado de Pensilvania.

Research progress into the principles and methods underlying capsular typing of Glaesserella parasuis.

Glaesserella parasuis (GPS) is an important bacterial pathogen of swine. Serotype identification has presented a bottleneck in GPS research since it was first identified as the pathogen causing Glässer's disease in pigs in 1910. This paper presents a systematic review of the history of the development and application of gel immunodiffusion (GID), indirect hemagglutination assay (IHA), and polymerase chain reaction (PCR) typing methods for GPS, and the discovery of their shared antigenic basis. It provides a systematic theoretical overview of the immunology and principles underlying the three typing methods and offers new ideas for research into the prevention and control of Glässer's disease. In 1992, GPS was first classified into serotypes 1-15 using GID based on GPS heat-stable antigens, but about 25% of the strains were found to be non-typeable, and the composition of their antigens for serotyping was unclear. In 2003, the IHA method was established based on saline-extracted antigens of GPS, whose sensitivity and typing rate were higher than for GID, although about 15% of strains were still found to be non-typeable. The results of IHA and GID typing are roughly consistent, since they share the same GPS surface polysaccharide serotyping antigens, although whether these are capsular polysaccharides, lipopolysaccharides, or other polysaccharides, remains to be determined. In 2013, the Capsular polysaccharide (CPS) synthetic gene clusters from GPS serotypes 1-15 were successfully analyzed, confirming that CPS is essential for the formation of antigens for serotyping. In 2015, primers were designed based on the specific target genes of GPS capsules to establish a PCR typing method (H-PCR) for GPS, which, however, could not identify serotypes 5 and 12. In 2017, a new PCR typing method (J-PCR) was established based on the specific target genes of GPS capsules, which could identify serotypes 5 and 12. A combination of the two PCR typing methods enables the typing of almost all GPS strains, and the consistency with GID and IHA was verified using molecular biological methods. The antigenic basis of the three typing methods was shown to involve the GPS capsule. PCR typing methods are characterized by simple operation, fast speed, and low cost, and can successfully solve many problems in GID and IHA serotyping, and so have become widely adopted.

Haemophilus influenzae Type b Vaccine Immunogenicity in American Indian/Alaska Native Infants.

OBJECTIVES: American Indian and Alaska Native (AI/AN) infants historically experienced a disproportionate burden of invasive Haemophilus influenzae type b (Hib) disease, especially early in life. PedvaxHIB vaccine is preferentially recommended for AI/AN infants because it elicits protective antibody levels postdose 1. Vaxelis, a hexavalent vaccine that contains the same Hib conjugate as PedvaxHIB but at lower concentration, is recommended for US children, but postdose 1 Hib immunogenicity data are needed to inform whether a preferential recommendation should be made for AI/AN infants. METHODS: We conducted a phase IV randomized, open-label, noninferiority trial comparing postdose 1 immunogenicity of Vaxelis to PedvaxHIB in AI/AN infants. Participants were randomized to receive a primary series of PedvaxHIB or Vaxelis. Serum samples collected 30 days postdose 1 were tested for anti-Hib immunoglobulin G antibody by enzyme-linked immunosorbent assay. The anti-Hib immunoglobulin G geometric mean concentration (GMC) ratio (Vaxelis/PedvaxHIB) was estimated by constrained longitudinal data analysis. Noninferiority was defined a priori as the lower bound of the 95% confidence interval (CI) of the GMC ratio ≥0.67. RESULTS: A total of 327 of the 333 infants enrolled in the study were included in the per-protocol analysis. The postdose 1 anti-Hib GMC was 0.41 µg/mL (95% CI 0.33-0.52) in the Vaxelis group (n = 152) and 0.39 µg/mL (95% CI 0.31-0.50) in the PedvaxHIB group (n = 146). The constrained longitudinal data analysis GMC ratio was 1.03 (95% CI 0.76-1.39). CONCLUSIONS: Postdose 1 immunogenicity of Vaxelis was noninferior to PedvaxHIB. Our findings support the use of Vaxelis in AI/AN children, a population with elevated risk of Hib disease.

Glaesserella parasuis serotype 4 exploits fibronectin via RlpA for tracheal colonization following porcine circovirus type 2 infection.

Porcine circovirus type 2 (PCV2) often causes disease through coinfection with other bacterial pathogens, including Glaesserella parasuis (G. parasuis), which causes high morbidity and mortality, but the role played by PCV2 and bacterial and host factors contributing to this process have not been defined. Bacterial attachment is assumed to occur via specific receptor-ligand interactions between adhesins on the bacterial cell and host proteins adsorbed to the implant surface. Mass spectrometry (MS) analysis of PCV2-infected swine tracheal epithelial cells (STEC) revealed that the expression of Extracellular matrix protein (ECM) Fibronectin (Fn) increased significantly on the infected cells surface. Importantly, efficient G. parasuis serotype 4 (GPS4) adherence to STECs was imparted by interactions with Fn. Furthermore, abrogation of adherence was gained by genetic knockout of Fn, Fn and Integrin ß1 antibody blocking. Fn is frequently exploited as a receptor for bacterial pathogens. To explore the GPS4 adhesin that interacts with Fn, recombinant Fn N-terminal type I and type II domains were incubated with GPS4, and the interacting proteins were pulled down for MS analysis. Here, we show that rare lipoprotein A (RlpA) directly interacts with host Fibronectin mediating GPS4 adhesion. Finally, we found that PCV2-induced Fibronectin expression and adherence of GPS4 were prevented significantly by TGF-ß signaling pathway inhibitor SB431542. Our data suggest the RlpA-Fn interaction to be a potentially promising novel therapeutic target to combat PCV2 and GPS4 coinfection.

The emergence of transposon-driven multidrug resistance in invasive nontypeable Haemophilus influenzae over the last decade.

Nontypeable Haemophilus influenzae (NTHi), once considered a harmless commensal, has emerged as a significant concern due to the increased prevalence of multidrug-resistant (MDR) strains and their association with invasive infections. This study aimed to explore the epidemiology and molecular resistance mechanisms of 51 NTHi isolates collected from patients with invasive infections in northern Taiwan between 2011 and 2020. This investigation revealed substantial genetic diversity, encompassing 29 distinct sequence types and 18 clonal complexes. Notably, 68.6% of the isolates exhibited ampicillin resistance, with 28 categorised as MDR and four isolates were even resistant to up to six antibiotic classes. Among the MDR isolates, 18 pulsotypes were identified, indicating diverse genetic lineages. Elucidation of their resistance mechanisms revealed 18 ß-lactamase-producing amoxicillin-clavulanate-resistant (BLPACR) isolates, 12 ß-lactamase-producing ampicillin-resistant (BLPAR) isolates, and 5 ß-lactamase-nonproducing ampicillin-resistant (BLNAR) isolates. PBP3 analysis revealed 22 unique substitutions in BLPACR and BLNAR, potentially contributing to cephem resistance. Notably, novel transposons, Tn7736-Tn7739, which contain critical resistance genes, were discovered. Three strains harboured Tn7739, containing seven resistance genes [aph(3')-Ia, blaTEM-1, catA, sul2, strA, strB, and tet(B)], while four other strains carried Tn7736, Tn7737, and Tn7738, each containing three resistance genes [blaTEM-1, catA, and tet(B)]. The emergence of these novel transposons underscores the alarming threat posed by highly resistant NTHi strains. Our findings indicated that robust surveillance and comprehensive genomic studies are needed to address this growing public health challenge.

Use of Haemophilus influenzae Type b-Containing Vaccines Among American Indian and Alaska Native Infants: Updated Recommendations of the Advisory Committee on Immunization Practices - United States, 2024.

Invasive Haemophilus influenzae type b (Hib) disease is a serious bacterial infection that disproportionally affects American Indian and Alaska Native (AI/AN) populations. Hib vaccination with a monovalent Hib conjugate vaccine consisting of Hib capsular polysaccharide (polyribosylribitol phosphate [PRP]) conjugated to outer membrane protein complex of Neisseria meningitidis serogroup B, PRP-OMP (PedvaxHIB, Merck and Co., Inc.) has historically been preferred for AI/AN infants, who are at increased risk for invasive Hib disease, because it provides substantial protection after the first dose. On June 26, 2024, CDC's Advisory Committee on Immunization Practices (ACIP) recommended that a hexavalent, combined diphtheria and tetanus toxoids and acellular pertussis (DTaP), inactivated poliovirus (IPV), Hib conjugate, and hepatitis B (HepB) vaccine, DTaP-IPV-Hib-HepB (Vaxelis, MSP Vaccine Company) should be included with monovalent PRP-OMP in the preferential recommendation for AI/AN infants because of the PRP-OMP Hib component. A primary Hib vaccination series consisting of either 1) monovalent PRP-OMP (2-dose series at ages 2 and 4 months) or 2) DTaP-IPV-Hib-HepB (3-dose series at ages 2, 4, and 6 months) is preferred for AI/AN infants. DTaP-IPV-Hib-HepB is only indicated for use in infants at ages 2, 4, and 6 months and should not be used for the booster doses of Hib, DTaP, or IPV vaccines. For the booster dose of Hib vaccine, no vaccine formulation is preferred for AI/AN children; any Hib vaccine (except DTaP-IPV-Hib-HepB) should be used. This report summarizes evidence considered for these recommendations and provides clinical guidance for the use of Hib-containing vaccines among AI/AN infants and children.

Trends in invasive Haemophilus influenzae serotype b (Hib) disease in England: 2012/13 to 2022/23.

INTRODUCTION: Haemophilus influenzae serotype b (Hib) conjugate vaccines have been highly successful in reducing the Hib disease worldwide. Recently, several European countries have reported an increase in invasive Hib disease. We aimed to describe the epidemiology, clinical characteristics, genomic trends, and outcomes of invasive Hib disease over the past 11 years in England. METHODS: The UK Health Security Agency (UKHSA) conducts national surveillance of invasive H influenzae disease and hosts a national reference laboratory for confirmation and serotyping. General practitioners are contacted to complete a surveillance questionnaire for confirmed Hib cases. Invasive Hib isolates routinely undergo whole genome sequencing. RESULTS: During 2012/13-2022/23, there were 6881 invasive H. influenzae infections, of which 5852 (85%) were serotyped; most isolates (4881, 83%) were non-typeable H. influenzae, followed by Hif (591, 10%), Hie (189, 3%), Hib (118, 2%) and Hia (54, 1.0%). The median age for invasive Hib disease was 51 years, and most cases (84%, 99/118) were in adults. Children accounted for 19 cases (16%), including 13 (11%) in <1 year-olds and 6 (5%) in 1-5-year-olds. Bacteraemic pneumonia was the most common diagnosis (66/118, 56%). Hib case-fatality rate was 5.9% (7/118), with the last fatality reported in 2016. Among 64 sequenced strains during 2016/17-2022/2023, most (56/64, 88%) belonged to the CC6 lineage (representing ST6 and single locus variants of ST6). CONCLUSIONS: In England, invasive Hib disease remains rare with no evidence of any increase in incidence and is rarely fatal, affecting mainly adults with underlying conditions, who typically develop pneumonia.

Development and implementation of a core genome multilocus sequence typing scheme for Haemophilus influenzae.

Haemophilus influenzae is part of the human nasopharyngeal microbiota and a pathogen causing invasive disease. The extensive genetic diversity observed in H. influenzae necessitates discriminatory analytical approaches to evaluate its population structure. This study developed a core genome multilocus sequence typing (cgMLST) scheme for H. influenzae using pangenome analysis tools and validated the cgMLST scheme using datasets consisting of complete reference genomes (N = 14) and high-quality draft H. influenzae genomes (N = 2297). The draft genome dataset was divided into a development dataset (N = 921) and a validation dataset (N = 1376). The development dataset was used to identify potential core genes, and the validation dataset was used to refine the final core gene list to ensure the reliability of the proposed cgMLST scheme. Functional classifications were made for all the resulting core genes. Phylogenetic analyses were performed using both allelic profiles and nucleotide sequence alignments of the core genome to test congruence, as assessed by Spearman's correlation and ordinary least square linear regression tests. Preliminary analyses using the development dataset identified 1067 core genes, which were refined to 1037 with the validation dataset. More than 70% of core genes were predicted to encode proteins essential for metabolism or genetic information processing. Phylogenetic and statistical analyses indicated that the core genome allelic profile accurately represented phylogenetic relatedness among the isolates (R 2 = 0.945). We used this cgMLST scheme to define a high-resolution population structure for H. influenzae, which enhances the genomic analysis of this clinically relevant human pathogen.

Salivary polyreactive antibodies and Haemophilus influenzae are associated with respiratory infection severity in young children with recurrent respiratory infections.

BACKGROUND: Recurrent respiratory tract infections (rRTIs) are a common reason for immunodiagnostic testing in children, which relies on serum antibody level measurements. However, because RTIs predominantly affect the respiratory mucosa, serum antibodies may inaccurately reflect local immune defences. We investigated antibody responses in saliva and their interplay with the respiratory microbiota in relation to RTI severity and burden in young children with rRTIs. METHODS: We conducted a prospective cohort study including 100 children aged <10 years with rRTIs, their family members and healthy healthcare professionals. Total and polyreactive antibody concentrations were determined in serum and saliva (ELISA); respiratory microbiota composition (16S rRNA sequencing) and respiratory viruses (quantitative PCR) were characterised in nasopharyngeal swabs. Proteomic analysis (Olink) was performed on saliva and serum samples. RTI symptoms were monitored with a daily mobile phone application and assessed using latent class analysis and negative binomial mixed models. RESULTS: Serum antibody levels were not associated with RTI severity. Strikingly, 28% of salivary antibodies and only 2% of serum antibodies displayed polyreactivity (p<0.001). Salivary polyreactive IgA was negatively associated with recurrent lower RTIs (adjusted OR 0.80, 95% CI 0.67-0.94) and detection of multiple respiratory viruses (adjusted OR 0.76, 95% CI 0.61-0.96). Haemophilus influenzae abundance was positively associated with RTI symptom burden (regression coefficient 0.05, 95% CI 0.02-0.08). CONCLUSION: These results highlight the importance of mucosal immunity in RTI severity and burden, and suggest that the level of salivary polyreactive IgA and H. influenzae abundance may serve as indicators of infection severity and burden in young children with rRTIs.

Transcriptome Analysis Reveals Novel Inflammatory Signalings to Glaesserella parasuis Infection.

Glaesserella parasuis (GPS) can cause severe systemic inflammation in pigs, resulting in huge economic losses to the pig industry. At present, no effective method is available for the prevention and control of GPS infection. Molecular breeding for disease resistance is imminent, but disease-resistance genes have not been identified. To study the mechanism of systemic acute inflammation caused by GPS, we established three in vitro infection models (3D4/21 cells, PK15 cells, and PAVEC cells) according to its infection path. There was no significant difference in apoptosis among the three kinds of cells after 12 h of continuous GPS stimulation, while inflammatory factors were significantly upregulated. Subsequent transcriptome analysis revealed 1969, 1207, and 3564 differentially expressed genes (DEGs) in 3D4/21 cells, PK15 cells, and PAVEC cells, respectively, after GPS infection. Many of the DEGs were predicted to be associated with inflammatory responses (C3, CD44, etc.); cell proliferation, growth and apoptosis; gene expression; and protein phosphorylation. Key signaling pathways, including S100 family signaling, bacteria and virus recognition, and pathogen-induced cytokine storm signaling, were enriched based on Ingenuity Pathway Analysis (IPA). Furthermore, a total of three putative transmembrane receptors and two putative G-protein-coupled receptors, namely F3, ICAM1, PLAUR, ACKR3, and GPRC5A, were identified by IPA among the three types of cells. ACKR3 and GPRC5A play pivotal roles in bacterial adhesion, invasion, host immune response and inflammatory response through the S100 family signaling pathway. Our findings provide new insights into the pathological mechanisms underlying systemic inflammation caused by GPS infection in pigs, and they lay a foundation for further research on disease-resistance breeding to GPS.

Genomic insight into the diversity of Glaesserella parasuis isolates from 19 countries.

Glaesserella parasuis is a commensal bacterial organism found in the upper respiratory tract of healthy pigs and the etiological agent of Glässer's disease, which causes severe economic losses in the swine industry. This study aimed to better understand the epidemiological characteristics of this opportunistic pathogen. We investigated the prevalence and distribution of sequence types (STs), serovars, antimicrobial resistance genes (ARGs), and potential virulence factors (VFs) in 764 G. parasuis isolates collected from diseased and healthy pigs from 19 countries, including China. Multilocus sequence typing showed a high degree of variation with 334 STs, of which 93 were not previously recognized. Phylogenetic analysis revealed two major clades distinguished by isolation year, source, country, and serovar. The dominant serovars of G. parasuis were serovars 4 (19.50%), 7 (15.97%), 5/12 (13.87%), and 13 (12.30%). Serovar 7 gradually became one of the dominant serovars in G. parasuis with more VFs and fewer ARGs. Serovars 4 and 5/12 were the most frequent serovars in diseased pigs, whereas serovars 2, 8, and 11 were predominant in healthy pigs. Serovars 7 and 13 possessed more VFs than the other serovars. This study provides novel insights into the global prevalence and epidemiology of G. parasuis and valuable clues for further investigation into the pathogenicity of G. parasuis, which will facilitate the development of effective vaccines.IMPORTANCEGlaesserella parasuis is a clinically important gram-negative opportunistic pathogen, which causes serious financial losses in swine industry on a global scale. No vaccine is known that provides cross-protection against all 15 serovars; furthermore, the correlation between serovar and virulence is largely unknown. This study provides a large number of sequenced strains in 19 countries and compares the genomic diversity of G. parasuis between diseased and healthy pigs. We found a slight change in the dominant serovar of G. parasuis in the world, with serovar 7 gradually emerging as one of the predominant serovars. The observed higher average number of VFs in this particular serovar strain challenges the previously held notion that serovar 7 is non-virulent, indicating a more complex virulence landscape than previously understood. Our analysis indicating that six ARGs [tet(B), sul2, aph(3')-Ia, aph (6)-Id, blaROB-1, and aph(3'')-Ib] are likely to be transmitted horizontally in their entirety. By analyzing VFs, we provided an improved understanding of the virulence of G. parasuis, and these key findings suggest that vaccine development will be challenging.

Invasive Nontypeable Haemophilus influenzae Disease Outbreak at an Elementary School - Michigan, May 2023.

In May 2023, the Detroit Health Department was notified of four cases of invasive nontypeable Haemophilus influenzae (Hi) disease among students attending the same elementary school and grade, all with illness onsets within 7 days. Three patients were hospitalized, and one died. Most U.S. cases of invasive Hi disease are caused by nontypeable strains. No vaccines against nontypeable or non-type b Hi strains are currently available. Chemoprophylaxis is not typically recommended in response to nontypeable Hi cases; however, because of the high attack rate (four cases among 46 students; 8.7%), rifampin prophylaxis was recommended for household contacts of patients with confirmed cases and for all students and staff members in the school wing where confirmed cases occurred. Only 10.8% of students for whom chemoprophylaxis was recommended took it, highlighting gaps in understanding among caregivers and health care providers about persons for whom chemoprophylaxis was recommended. Public health authorities subsequently enhanced communication and education to the school community, improved coordination with health care partners, and established mass prophylaxis clinics at the school. This outbreak highlights the potential for nontypeable Hi to cause serious illness and outbreaks and the need for chemoprophylaxis guidance for nontypeable Hi disease. Achieving high chemoprophylaxis coverage requires education, communication, and coordination with community and health care partners.

Respiratory Pathogens at Exacerbation in Chronic Bronchitis With Airway Bacterial Colonisation: A Cohort Study.

BACKGROUND AND OBJECTIVE: COPD and bronchiectasis are common causes of morbidity, particularly around exacerbation. Colonisation with respiratory pathogens can increase the frequency and severity of exacerbations. However, bacterial and viral presence at exacerbation in people with airway colonisation has not been well studied. METHODS: A 6-month cohort study of participants (n = 30) with chronic bronchitis due to bronchiectasis (n = 26) and/or COPD (n = 13) and colonisation with Pseudomonas aeruginosa or Haemophilus influenzae was proven on two sputum cultures at exacerbation in the previous 12 months. Participants were provided self-management education and collected sputum samples daily. Sputum samples at baseline (at least 14 days before or after an exacerbation) and at each exacerbation were examined for a panel of 34 respiratory pathogens using commercially available RT-PCR kits and compared to results obtained using culture methods for the detection of bacteria. RESULTS: Participants provided 29 baseline samples and 71 samples at exacerbation. In 17/29 baseline samples, RT-PCR analysis confirmed the organism demonstrated by culture, while 12 samples showed a discrepancy from culture results. Most exacerbations (57.7%) were not associated with acquiring new bacteria or viruses, while 19.8% showed new bacteria, 15.7% new viruses and 7% both new viruses and bacteria. CONCLUSION: Over half of exacerbations were not associated with new organisms in this cohort of participants with chronic bronchitis and colonisation. However, 26.8% demonstrated a new bacterial species in sputum, which is relevant for antibiotic therapy. Baseline RT-PCR and culture results were discordant in one-third of participants.

A severe asthma phenotype of excessive airway Haemophilus influenzae relative abundance associated with sputum neutrophilia.

BACKGROUND: Severe asthma (SA) encompasses several clinical phenotypes with a heterogeneous airway microbiome. We determined the phenotypes associated with a low α-diversity microbiome. METHODS: Metagenomic sequencing was performed on sputum samples from SA participants. A threshold of 2 standard deviations below the mean of α-diversity of mild-moderate asthma and healthy control subjects was used to define those with an abnormal abundance threshold as relative dominant species (RDS). FINDINGS: Fifty-one out of 97 SA samples were classified as RDSs with Haemophilus influenzae RDS being most common (n = 16), followed by Actinobacillus unclassified (n = 10), Veillonella unclassified (n = 9), Haemophilus aegyptius (n = 9), Streptococcus pseudopneumoniae (n = 7), Propionibacterium acnes (n = 5), Moraxella catarrhalis (n = 5) and Tropheryma whipplei (n = 5). Haemophilus influenzae RDS had the highest duration of disease, more exacerbations in previous year and greatest number on daily oral corticosteroids. Hierarchical clustering of RDSs revealed a C2 cluster (n = 9) of highest relative abundance of exclusively Haemophilus influenzae RDSs with longer duration of disease and higher sputum neutrophil counts associated with enrichment pathways of MAPK, NF-κB, TNF, mTOR and necroptosis, compared to the only other cluster, C1, which consisted of 7 Haemophilus influenzae RDSs out of 42. Sputum transcriptomics of C2 cluster compared to C1 RDSs revealed higher expression of neutrophil extracellular trap pathway (NETosis), IL6-transignalling signature and neutrophil activation. CONCLUSION: We describe a Haemophilus influenzae cluster of the highest relative abundance associated with neutrophilic inflammation and NETosis indicating a host response to the bacteria. This phenotype of severe asthma may respond to specific antibiotics.

Evolution of mutations in the ftsI gene leading to amino acid substitutions in PBP3 in Haemophilus influenzae strains under the selective pressure of ampicillin and cefuroxime.

BACKGROUND: Aminopenicillins are recommended agents for non-invasive Haemophilus influenzae infections. One of the mechanisms of resistance to ß-lactams is the alteration of the transpeptidase region of penicillin binding protein 3 (PBP3) which is caused by mutations in the ftsI gene. It was shown that exposure to beta-lactams has a stimulating effect on increase of prevalence of H. influenzae strains with the non-enzymatic mechanism of resistance. OBJECTIVES: The aim of our study was to compare the mutational potential of ampicillin and cefuroxime in H. influenzae strains, determination of minimum inhibitory concentration and the evolution of mutations over time, focusing on amino acid substitutions in PBP3. METHODS: 30 days of serial passaging of strains in liquid broth containing increasing concentrations of ampicillin or cefuroxime was followed by whole-genome sequencing. RESULTS: On average, cefuroxime increased the minimum inhibitory concentration more than ampicillin. The minimum inhibitory concentration was increased by a maximum of 32 fold. Substitutions in the PBP3 started to appear after 15 days of passaging. In PBP3, cefuroxime caused different substitutions than ampicillin. CONCLUSIONS: Our experiment observed differences in mutation selection by ampicillin and cefuroxime. Selection pressure of antibiotics in vitro generated substitutions that do not occur in clinical strains in the Czech Republic.

Sequential development of diffuse panbronchiolitis and myasthenia gravis after thymectomy for thymic neoplasm: a case report.

BACKGROUND: Myasthenia gravis (MG) is the most common paraneoplastic disorder associated with thymic neoplasms. MG can develop after thymectomy, and this condition is referred to post-thymectomy myasthenia gravis (PTMG). Diffuse panbronchiolitis (DPB), is a rare form of bronchiolitis and is largely restricted to East Asia, has been reported in association with thymic neoplasms. Only three cases of combined MG and DPB have been reported in the literature. CASE PRESENTATION: A 45-year-old Taiwanese woman presented to our hospital with productive cough, rhinorrhea, anosmia, ear fullness, shortness of breath, and weight loss. She had a history of thymoma, and she underwent thymectomy with adjuvant radiotherapy 7 years ago. Chest computed tomography scan revealed diffuse bronchitis and bronchiolitis. DPB was confirmed after video-assisted thoracoscopic surgery lung biopsy, and repeated sputum cultures grew Pseudomonas aeruginosa. She has been on long-term oral azithromycin therapy thereafter. Intravenous antipseudomonal antibiotics, inhaled amikacin, as well as oral levofloxacin were administered. Three months after DPB diagnosis, she developed ptosis, muscle weakness, and hypercapnia requiring the use of noninvasive positive pressure ventilation. MG was diagnosed based on the acetylcholine receptor antibody and repetitive stimulation test results. Her muscle weakness gradually improved after pyridostigmine and corticosteroid therapies. Oral corticosteroids could be tapered off ten months after the diagnosis of MG. She is currently maintained on azithromycin, pyridostigmine, and inhaled amikacin therapies, with intravenous antibiotics administered occasionally during hospitalizations for respiratory infections. CONCLUSIONS: To our knowledge, this might be the first case report of sequential development of DPB followed by PTMG. The coexistence of these two disorders poses a therapeutic challenge for balancing infection control for DPB and immunosuppressant therapies for MG.

HbpA from Glaesserella parasuis induces an inflammatory response in 3D4/21 cells by activating the MAPK and NF-κB signalling pathways and protects mice against G. parasuis when used as an immunogen.

Glaesserella parasuis is usually a benign swine commensal in the upper respiratory tract, but virulent strains can cause systemic infection characterized by pneumonia, meningitis, and fibrinous polyserositis. The intensive pulmonary inflammatory response following G. parasuis infection is the main cause of lung injury and death in pigs. Vaccination has failed to control the disease due to the lack of extended cross-protection. Accumulating evidence indicates that the heme-binding protein A (HbpA) is a potential virulence determinant and a promising antigen candidate for the development of a broader range of vaccines. However, it is not yet known whether HbpA contributes to G. parasuis virulence or has any potential immune protective effects against G. parasuis. Here, we show that HbpA can induce the transcription and secretion of proinflammatory cytokines (IL-6, TNF-α, and MCP-1) in porcine alveolar macrophages (PAM, 3D4/31). The HbpA protein is recognized by Toll-like receptors 2 and 4 on 3D4/21 macrophages, resulting in the activation of MAP kinase and NF-κB signalling cascades and the transcription and secretion of proinflammatory cytokines. HbpA contributes to virulence and bacterial pulmonary colonization in C57BL/6 mice and plays a role in adhesion to host cells and evasion of the bactericidal effect of pulmonary macrophages. In addition, mice immunized with HbpA were partially protected against challenge by G. parasuis SC1401. The results suggest that HbpA plays an important role in the pathogenesis of disease caused by G. parasuis and lay a foundation for the development of a subunit or chimeric anti-G. parasuis vaccine.