Unexpected and Sudden Death Due to Undiagnosed Moraxella catarrhalis Meningoencephalitis in a 40-day-old Infant: Case Report and Literature Review

Sudden death in a newborn from cerebral venous sinus thrombosis resulting from meningitis

Septic cerebral venous sinus thrombosis is a rare but often fatal complication caused by bacterial meningitis and paranasal sinusitis.We report a particular case of the sudden and unexpected death of a six-day-old infant from unrecognised acute meningitis that caused a thrombotic occlusion of the venous sinuses (with the particular involvement of the torcular Herophili at the confluence of sinuses) resulting in subdural haemorrhage.This case report alerts paediatricians and neonatologists to the importance of promptly considering a possible diagnosis of meningitis without delay to avoid the fatal complications described here. As in all cases of sudden infant death our case study underlines the need for a thorough autopsy, accompanied by histological analysis, in order to identify the causes of the underlying pathological mechanisms causing death and to ensure an adequate differential diagnosis.

Moraxella nasibovis sp. nov., Isolated from a Cow with Respiratory Disease

Strain ZY190618T, isolated from the nasal cavity of a cow with respiratory disease, was subjected to taxonomic characterization. Cells of the strain were Gram-stain-negative, aerobic and coccus-shaped. Phylogenetic analysis based on 16 S rRNA gene sequences indicated that the strain belonged to the genus Moraxella with the highest similarity of 98.1% to Moraxella nasovis CCUG 75922T. Phylogenomic analysis based on 810 single-copy genes revealed that the strain was a member of the genus Moraxella and formed a deep and separated clade within the genus. The strain showed the highest orthologous average nucleotide identity (OrthoANI) value of 77.1% with Moraxella ovis CCUG 354T and digital DNA-DNA hybridization (dDDH) value of 24.7% with Moraxella equi NCTC 11012T, respectively. The DNA G + C content was 46.5 mol%. The strain optimally grew at 37 °C (temperature range, 24-42 °C), at pH 8.0 (pH range, 6.0-9.0) and with 1.5% (w/v) NaCl (NaCl range, 0.5-3.0%). The strain contained C18:1 ω9c as the sole predominant fatty acid (> 5 %) and CoQ-8 as the major respiratory quinone. The major polar lipids included phosphatidylglycerol, phosphatidylethanolamine, cardiolipin, monolysocardiolipin and hemibismonoacylglycerophosphate. Based on these data, strain ZY190618T clearly represents a novel species in the genus Moraxella, for which the name Moraxella nasibovis sp. nov. (The type strain ZY190618T = CCUG 75921T = CCTCC AB 2021472T) is proposed.

Moraxella nasicaprae sp. nov., Isolated from a Goat with Respiratory Disease

A novel Gram-stain-negative, aerobic, irregular coccus designated as ZY201224^T, was isolated from the nasal cavity of a goat with respiratory disease in a goat farm, located at Jianshui, Yunnan Province, PR China and its taxonomic position was clarified using a polyphasic approach. The strain grew optimally at 37 °C, at pH 8.0 and in the presence of 1% NaCl. Phylogenetic analysis based on 16S rRNA gene sequence and phylogenomic analysis based on 808 single-copy genes revealed that the strain is affiliated to the genus Moraxella and is distinct from the recognized species of the genus. The 16S rRNA gene sequence similarity analysis indicated that the strain is most closely related to Moraxella caviae CCUG 355^T with sequence similarity of 98.1%. The genomic OrthoANI and digital DNA-DNA hybridization (dDDH) values between the strain and the type strains of Moraxella species were no higher than 74.7% (Moraxella pluranimalium CCUG 54913^T) and 26.0% (Moraxella oblonga NBRC 102422^T), respectively. The G + C content of the complete genome sequence was 43.6 mol%. The strain contained CoQ-8 as the major respiratory quinone, and C_18:1ω9c, C17:1ω8c, C16:0 and summed feature 3 (C_16:1 ω7c and/ or C_16:1ω6c) as the predominant fatty acids (> 5%). The major polar lipids comprised phosphatidylglycerol (PG), cardiolipin (CL), monolysocardiolipin (MLCL), phosphatidylethanolamine (PE) and lysophosphatidylglycerol (LPG). Based on these taxonomic characterizations, strain ZY201224^T represents a novel species of the genus Moraxella, for which the name Moraxella nasicaprae sp. nov. is proposed. The type strain is ZY201224^T (= CCTCC AB 2021474^T = NBRC 115473^T).

Moraxella nasovis sp. nov., isolated from a sheep with respiratory disease

A novel Gram-stain-negative, aerobic, coccus-shaped bacteria, designated ZY201115T, was isolated from the nasal cavity of a sheep with respiratory disease in Yunnan Province, south-west China, and its taxonomic affiliation was studied by applying a polyphasic approach. The strain grew at 18–41 °C (optimum, 37 °C), at pH 6.0–9.0 (optimum, pH 8.0) and in 0.5–3.0% (w/v) NaCl (optimum, 1.0 % NaCl). Phylogenetic analysis based on 16S rRNA gene sequences showed that the strain is affiliated to the genus Moraxella with highest similarity to Moraxella bovis ATCC 10900T (96.6 %). Phylogenomic analysis based on 811 single-copy genes also indicated that the strain represents a novel species in the genus Moraxella and formed a deep and separated clade with Moraxella caviae NCTC 10293T. The highest genomic orthologous average nucleotide identity and digital DNA–DNA hybridization values between the strain and the type strains in the genus Moraxella were 73.7% ( M. caviae NCTC 10293T) and 25.3% ( Moraxella osloensis CCUG 350T), respectively. The G+C content of the complete genome sequence was 42.1 mol%. The predominant fatty acids (>5 %) were C18:1 ω9c, C17:1 ω8c, C12:03OH and summed feature 3 (C16:1 ω7c and/or C16:1 ω6c). The major polar lipids were phosphatidylglycerol, cardiolipin, monolysocardiolipin, phosphatidylethanolamine and hemibismonoacylglycerophosphate. The major respiratory quinone was CoQ-8. On the basis of the results of phylogenetic, phenotypic and chemotaxonomic characterizations, strain ZY201115T clearly represents a novel species of the genus Moraxella , for which the name Moraxella nasovis sp. nov. is proposed. The type strain is ZY201115T (=CCTCC AB 2021473T=CCUG 75922T).

Correlation of Moraxella catarrhalis macrolide susceptibility with the ability to adhere and invade human respiratory epithelial cells

Recently, the prevalence of macrolide-resistant Moraxella catarrhalis has been reported, especially among Chinese children. The fitness cost of resistance is reported to render the resistant bacteria less virulent. To investigate the correlation between macrolide susceptibility of M. catarrhalis and pathogenicity, the whole genome of 70 M. catarrhalis isolates belonging to four clonal complexes with different macrolide susceptibilities was sequenced. The gene products were annotated with the Gene Ontology terms. Based on 46 extracted essential virulence genes, 19 representative isolates were selected to infect type II alveolar cells (A549 cells). The ability of these isolates to adhere and invade human epithelial cells and to produce cytokines was comparatively analysed. Furthermore, mice were infected with a pair of M. catarrhalis isolates with different pathogenic behaviours and macrolide susceptibilities to examine pulmonary clearance, histological findings, and the production of cytokines. The percentages of annotations for binding, metabolic process, cellular process, and cell were non-significantly different between the macrolide-resistant and macrolide-susceptible groups. The presence of uspA2, uspA2H, pilO, lbpB, lex1, modM, mboIA, and mboIB significantly differed among the four clonal complexes and macrolide susceptibility groups. Furthermore, compared with those in macrolide-susceptible isolates, the adhesion ability was stronger (P = 0.0019) and the invasion ability was weaker (P < 0.0001) in the macrolide-resistant isolates. Mouse experiments revealed that pulmonary macrophages elicit immune responses against M. catarrhalis infection by significantly upregulating the Csf2, Il4, Il13, Il1b, Il6, Tnf, and Il18. Therefore, M. catarrhalis populations exhibited diverse pathogenicity in vitro and in vivo.