Coagulase-negative staphylococci are the main causes of bacterial meningitis in duck.

Since September 2018, serious meningitis has been found on some breeding-duck farms in Shandong Province, China. A large number of ducks exhibit severe neurological symptoms. The ducks were randomly selected for laboratory testing. Duck brain samples were collected using standard sterile techniques, and the staphylococci isolates were detected in 404 (70.14%) out of 576 brain samples. A total of 525 coagulase-negative staphylococci (CoNS) strains were isolated, including 6 species: Staphylococcus sciuri (S. sciuri) (67.24%, 353/525), Staphylococcus epidermidis (S. epidermidis) (9.71%, 51/525), Staphylococcus saprophyticus (S. saprophyticus) (8.38%, 44/525), Staphylococcus lentus (S. lentus) (7.62%, 40/525), Staphylococcus haemolyticus (S. haemolyticus) (2.48%, 13/525), and Staphylococcus xylosus (S. xylosus) (4.57%, 24/525). Mixed strain infections were detected in 121 (29.95%) infected presentations. The antimicrobial susceptibility testing indicated that 40.38% of the isolates exhibited multi-drug resistance, and 53.90% of the strains were methicillin-resistant strains by amplification of the methicillin resistance gene (mecA) gene. Through experimental reproduction of the disease, we determined that the CoNS strains were the leading pathogens causing bacterial meningitis in ducks. Although these CoNS strains does not directly cause the death of sick ducks, they still cause large economic losses due to the retarded growth and development of the sick ducks, lower feed returns, and lower grades of processed duck products. The results of this study will contribute to our understanding of the epidemiology and pathogenesis of CoNS and be helpful in the prevention and treatment of the infection.

Clinical presentation, treatment, and outcome of 24 dogs with bacterial meningitis or meningoencephalitis without empyema (2010-2020).

BACKGROUND: Bacterial meningitis (BM) and meningoencephalitis (BMEM) are associated with high case fatality rates and neurologic sequelae in people, but limited data exists on outcome in dogs. HYPOTHESIS/OBJECTIVES: To report the clinicopathologic features, treatment and outcome of BM/BMEM in dogs, with a focus on clinical presentation, relapse and long-term neurological deficits. ANIMALS: Twenty-four client-owned dogs diagnosed with BM/BMEM without empyema. METHODS: Retrospective case series of dogs diagnosed with BM/BMEM from 5 veterinary referral hospitals between January 2010 and August 2020. RESULTS: Twenty-four dogs were included. Median duration of clinical signs was 2 days (range ≤24 hours to 30 days) and signs recorded included pyrexia (3) and cervical hyperesthesia (10). Neurological deficits were present in 18 dogs including altered mentation (12), ataxia (8), nonambulatory status (8), head tilt (8), and cranial nerve deficits (13). Intracellular bacteria were visualized on cerebrospinal fluid (CSF) analysis in 15/24 dogs, with positive CSF bacteriological culture in 8/21. Otitis media/interna (OMI) was diagnosed in 15/24 dogs, of which 6/15 dogs underwent total ear canal ablation and lateral bulla osteotomy. Twenty dogs survived to hospital discharge. Median duration of antibiotic administrations was 8 weeks (range, 2-16 weeks). Glucocorticoids were administered to 15 dogs. Median follow-up time was 92 days (range, 10-2233 days). Residual neurological deficits were reported in 9 dogs, with a single case of suspected relapse. CONCLUSIONS AND CLINICAL IMPORTANCE: Clinical signs were variable in dogs with BM/BMEM, the nidus of bacterial infection was often OMI and the majority of dogs made a full recovery with treatment.

Meningoencephalomyelitis in domestic cats: 3 cases of Pasteurella multocida infection and literature review.

Neurologic diseases are common in domestic cats, and infectious agents are suspected to be the primary cause in 30-45% of cases. Among infectious etiologies, those of bacterial origin are only sporadically characterized in the literature, with few of these reports correlating gross and histologic findings with confirmatory bacteriologic identification. Here, we describe bacterial meningitis and meningoencephalomyelitis associated with Pasteurella multocida in 3 domestic cats. Purulent exudate expanding the cerebral meninges was grossly evident in 2 of the cases. In all 3 cases, histologic changes included multifocal suppurative-to-necrosuppurative meningitis and/or meningoencephalomyelitis of variable severity. Intralesional colonies of gram-negative, short rod-shaped to coccobacillary bacteria were evident histologically in only 1 case. P. multocida was confirmed by routine bacteriologic culture in all cases. Based on our cases, we hypothesize that the upper respiratory system serves as the main portal of entry for P. multocida, leading to invasion of the central nervous system and possible systemic hematogenous dissemination. A case series of meningoencephalomyelitis associated with P. multocida infection in cats has not been reported previously, to our knowledge. We also review briefly other causes of meningoencephalomyelitis in cats.

Bacterial meningitis after dental extraction in a 17-year-old horse.

Dental extractions in horses may result in bacteremia, which can lead to systemic complications. Bacterial meningitis following oral cheek tooth extractions in a 17-year-old Thoroughbred gelding is described in this report. The bacterial meningitis was confirmed by histopathology. The gelding was presented for evaluation of intermittent fever, loose feces, and mild colic signs which started 5 days after cheek tooth extraction. This case illustrates a rare complication associated with oral tooth extraction in a horse and highlights the unusual presenting features of meningitis. Key clinical message: Bacterial meningitis secondary to oral cheek tooth extraction should be considered as differential diagnosis; particularly in cases with the development of pyrexia a few days after the procedure.

Méningite bactérienne après extraction dentaire chez un cheval de 17 ans. Les extractions dentaires chez les chevaux peuvent entraîner une bactériémie, ce qui peut amener des complications systémiques. Un cas de méningite bactérienne à la suite d'extractions buccales de dents jugales chez un hongre pur-sang de 17 ans est décrite dans ce rapport. La méningite bactérienne a été confirmée par histopathologie. Le hongre a été présenté pour évaluation d'une fièvre intermittente, de selles molles et de signes de coliques légers qui ont commencé 5 jours après l'extraction de la dent jugale. Ce cas illustre une complication rare associée à l'extraction dentaire orale chez un cheval et met en évidence des caractéristiques inhabituelles de la méningite.Message clinique clé :La méningite bactérienne secondaire à l'extraction buccale des dents jugales doit être considérée comme un diagnostic différentiel, en particulier dans les cas de développement d'une pyrexie quelques jours après l'intervention.(Traduit par Dr Serge Messier).

Role of Bacterial and Host DNases on Host-Pathogen Interaction during Streptococcus suis Meningitis.

Streptococcus suis is a zoonotic agent causing meningitis in pigs and humans. Neutrophils, as the first line of defense against S. suis infections, release neutrophil extracellular traps (NETs) to entrap pathogens. In this study, we investigated the role of the secreted nuclease A of S. suis (SsnA) as a NET-evasion factor in vivo and in vitro. Piglets were intranasally infected with S. suis strain 10 or an isogenic ssnA mutant. DNase and NET-formation were analyzed in cerebrospinal fluid (CSF) and brain tissue. Animals infected with S. suis strain 10 or S. suis 10ΔssnA showed the presence of NETs in CSF and developed similar clinical signs. Therefore, SsnA does not seem to be a crucial virulence factor that contributes to the development of meningitis in pigs. Importantly, DNase activity was detectable in the CSF of both infection groups, indicating that host nucleases, in contrast to bacterial nuclease SsnA, may play a major role during the onset of meningitis. The effect of DNase 1 on neutrophil functions was further analyzed in a 3D-cell culture model of the porcine blood-CSF barrier. We found that DNase 1 partially contributes to enhanced killing of S. suis by neutrophils, especially when plasma is present. In summary, host nucleases may partially contribute to efficient innate immune response in the CSF.

Proteomics analysis of important molecules in serum from meningitic piglets caused by Streptococcus suis serotype 2.

INTRODUCTION: Streptococcus suis serotype 2 (SS2) is an important zoonotic pathogen that causes meningitis in China. This study's aim was comparative analysis of serum proteomics from meningitis and non-meningitis piglets. METHODOLOGY: SS2 meningitis and non-meningitis piglet models were established. The serum samples were collected and analyzed by label-free LC-MS/MS proteomics technology. Differentially expressed proteins (DEPs) from serum were screened out by comparing the meningitis group and non-meningitis group to the healthy group (M/C; N/C), respectively. And then, globally and comparative analysis of DEPs in "M/C" and "N/C" in serum were performed using bioinformatics method. Finally, we comparatively analyzed the serum and cerebrospinal fluid proteomics in piglets that lived with meningitis. RESULTS: We obtained 316 and 191 DEPs from "M/C" and "N/C" which classification visualizations were established. 157 DEPs were common in both groups and 159 DEPs were unique to the "M/C". These DEPs and the signaling pathways which they participated in were visualized. Moreover, some DEPs which participated in multiple pathways were discovered and the interaction between 159 DEPs was also mapped. 39 common DEPs were also screened out in serum and cerebrospinal fluid during meningitis, and signaling pathways associated with these DEPs were further visualized. CONCLUSIONS: DEPs in "M/C" and "N/C" were comparatively analyzed and the similarities and differences of these DEPS which were involved in signal pathways were summarized. Moreover, several important molecules were screened out.

Neurological symptoms and mortality associated with Streptococcus gallolyticus subsp. pasteurianus in calves.

Suppurative meningitis-meningoencephalitis (M-ME) is a sporadic disease in neonatal ungulates and only a few studies have reported the involvement of Streptococcus bovis/Streptococcus equinus complex (SBSEC) members in bovine neonatal M-ME. The SBSEC taxonomy was recent revised and previous biotype II/2 was reclassified as S. gallolyticus subsp. pasteurianus (SGP). The aim of this study was to describe a case of fatal neonatal neurological syndrome associated with SGP in calves. Ten calves were monitored because of neurological hyperacute symptoms associate with bilateral hypopyon and death. They were not fed with maternal colostrum; two of them died and were subjected to bacteriological, histopathological and biomolecular analysis as well as antibiotic susceptibility test. Both animals presented lesions mostly concentrated to meninges and brain and had bilateral hypopyon. Nine strains isolated in purity from brain, ocular humors and colon were identified as S. bovis group by using the API Strep system and as S. gallolyticus by using the 16S rRNA sequence. Two of these strains where subjected to WGS analysis that confirmed the sub-species identification and the clonality of the two SGP strains. The strains were found resistant to OT, SXT, MTZ and EN and susceptible to AMP, AMC, KZ and CN. We hypothesized that the syndrome observed could be due to the lack of maternal colostrum feeding. A timely and precise diagnosis could have likely prevented the death of the calves and, since the zoonotic potential of SBSECs members is known, accurate and rapid identification is required.

Validation of IgY for the diagnosis of Streptococcus agalactiae-caused endocarditis and bacterial meningitis in Nile tilapia (Oreochromis niloticus).

Streptococcus agalactiae (Sta), which belongs to Lancefield group B, causes sepsis, endocarditis and bacterial meningitis in human neonates and Nile tilapia. Because the pathophysiology of Sta infection is partially similar in both species, the identification of biomarkers for the diagnosis and study of this disease is of importance for human and animal health. Therefore, in the present study, we produced an immunoglobulin Y (IgY) by immunizing laying hens with Sta proteins and evaluated its ability to detect Sta in paraffinized tilapia brain and cardiac tissue by direct immunofluorescence (IMF) and indirect immunohistochemistry (IHC). The IgY produced was effective in the diagnosis of Sta infection in Nile tilapia, justifying the use of this species as a biomodel for the study of this disease.

Pathogenic Elizabethkingia miricola Infection in Cultured Black-Spotted Frogs, China, 2016.

Multiregional outbreaks of meningitis-like disease caused by Elizabethkingia miricola were confirmed in black-spotted frog farms in China in 2016. Whole-genome sequencing revealed that this amphibian E. miricola strain is closely related to human clinical isolates. Our findings indicate that E. miricola can be epizootic and may pose a threat to humans.

Vibrio parahaemolyticus- and V. alginolyticus-associated meningo-encephalitis in a bottlenose dolphin (Tursiops truncatus) from the Adriatic coast of Italy.

A case of Vibrio parahaemolyticus- and V. alginolyticus-associated meningo-encephalitis in a bottlenose dolphin (Tursiops truncatus) found stranded along the Adriatic coast of Italy in 2016 is herein reported, along with a minireview on V. parahaemolyticus and V. alginolyticus infections in aquatic mammals. Macroscopically, two abscesses were found in the dolphin's forebrain, along with an extensive, bilateral, parasitic broncho-pneumonia. Histologically, a suppurative-to-pyogranulomatous meningo-encephalitis involved the brain but not the cerebellum. Microbiological investigations yielded isolation of V. parahaemolyticus and V. alginolyticus from the aforementioned abscesses and from the brain parenchyma, respectively, with simultaneous recovery of Shewanella algae from the heart and of Photobacterium damselae from a blowhole swab. Although V. parahaemolyticus and V. alginolyticus, which are widely distributed across marine ecosystems worldwide, likely played a role in the development of the suppurative meningo-encephalitis in this dolphin, we are not aware of previous isolations of any of these two bacteria neither from cetacean brain lesions, nor from abscesses in aquatic mammals.

Peracute Bacterial Meningitis due to Infection with Klebsiella pneumoniae in Captive-bred Ruffed Lemurs (Varecia variegate).

We describe the development of neurological signs in four juvenile black-and-white ruffed lemurs (Varecia variegate), housed at a petting zoo in Japan. The clinical course was severe, with three lemurs dying within 1 day of the appearance of clinical signs. The other lemur was treated and survived. Pathological analyses demonstrated meningitis and the presence of gram-negative bacilli in the cerebrum, cerebellum, palatine tonsil and liver. Klebsiella pneumoniae was isolated from the brain of all of the dead lemurs. Multilocus sequence typing analysis showed that all the isolates were sequence type 86 (ST86). To our knowledge, this is the first determination of K. pneumoniae infection in ruffed lemurs of this genus. K. pneumoniae infection may represent a risk to lemurs and people who come into contact with infected animals.

Cerebral Disorders of Calves.

Neurologic diseases of the cerebrum are relatively common in cattle. In calves, the primary cerebral disorders are polioencephalomalacia, meningitis, and sodium toxicity. Because diagnostic testing is not always readily available, the practitioner must often decide on a course of treatment based on knowledge of the likely disease, as well as his or her own clinical experience. This is particularly true with neurologic diseases in which the prognosis is often poor and euthanasia may be the most humane outcome. This article reviews the most common diseases affecting the cerebrum of calves with a focus on pathophysiology, diagnosis, and treatment.

Initial steps of the pathogenesis of the infection caused by Streptococcus suis: fighting against nonspecific defenses.

Interactions between a bacterial pathogen and its potentially susceptible host are initiated with the colonization step. During respiratory/oral infection, the pathogens must compete with the normal microflora, resist defense mechanisms of the local mucosal immunity, and finally reach, adhere, and breach the mucosal epithelial cell barrier in order to induce invasive disease. This is the case during infection by the swine and zoonotic pathogen Streptococcus suis, which is able to counteract mucosal barriers to induce severe meningitis and sepsis in swine and in humans. The initial steps of the pathogenesis of S. suis infection has been a neglected area of research, overshadowed by studies on the systemic and central nervous phases of the disease. In this Review article, we provide for the first time, an exclusive focus on S. suis colonization and the potential mechanisms involved in S. suis establishment at the mucosa, as well as the mechanisms regulating mucosal barrier breakdown. The role of mucosal immunity is also addressed. Finally, we demystify the extensive list of putative adhesins and virulence factors reported to be involved in the initial steps of pathogenesis by S. suis.

Biological activities of suilysin: role in Streptococcus suis pathogenesis.

Streptococcus suis is an important swine and zoonotic pathogen equipped with several virulence factors. The pore-forming toxins are the most abundant bacterial toxins and classified as critical virulence (associated) factors of several pathogens. The role of suilysin (SLY), a pore-forming cholesterol-dependent cytolysin of S. suis, as a true virulence factor is under debate. Most of the bacterial toxins have been reported to modulate the host immune system to facilitate invasion and subsequent replication of bacteria within respective host cells. SLY has been demonstrated to play an important role in the pathogenesis of S. suis infection and inflammatory response in vitro and in vivo. This review highlights the contributions of SLY to the pathogenicity of S. suis. It will address its role during the development of S. suis meningitis in pigs, as well as humans, and discuss SLY as a potential vaccine candidate.

Detection and DNA quantification of Enterococcus casseliflavus in a foal with septic meningitis.

CASE DESCRIPTION A 3-month-old 180-kg (396-lb) Hanoverian colt was examined because of fever, lethargy, inappetence, drooping of the left ear, and stiff neck posture. Initial treatment included empirical antimicrobial treatment and NSAIDs. CLINICAL FINDINGS Initial findings were consistent with CNS anomalies. Endoscopy revealed hyperemia, ecchymosis, and some mucopurulent exudate in the right guttural pouch. Hematologic findings were consistent with neutrophilic inflammation. On the third day of hospitalization, severe neurologic signs were observed. Computed tomography of the skull revealed a comminuted fracture of the axial aspect of the right mandibular condyle. Examination of CSF revealed turbidity, xanthochromia, and intracellular and extracellular cocci, consistent with septic meningitis. After DNA extraction from blood and CSF, sequenced products from a PCR assay for the bacterial 16S rRNA gene were 99% identical to Enterococcus casseliflavus. Microbial culture of CSF and blood samples yielded bacteria with Enterococcus spp morphology; antimicrobials were selected on the basis of susceptibility testing that identified the isolate as vancomycin resistant. A quantitative PCR assay was used to estimate Enterococcus DNA concentrations in CSF and blood. TREATMENT AND OUTCOME Treatment for E casseliflavus meningitis, including trimethoprim-sulfadiazine and ampicillin sodium administration, resulted in resolution of clinical signs. Culture of CSF and blood samples after 12 days of the targeted treatment yielded no growth. CLINICAL RELEVANCE To the authors' knowledge, this was the first report of E casseliflavus meningitis in a horse. Treatment was successful; vancomycin-resistant enterococci can be a clinical problem and may potentially be zoonotic.

[Characterization of ibeB gene of meningitic Escherichia coli strains in calves from Xinjiang].

Objective: To understand the molecular biology information of ibeB gene of meningitic Escherichia coli isolates in calves. Methods: The strain used was isolated from the brain and liver tissue of calves died from Meningitis. It was identified to be an O161-K99-STa pathogenic Escherichia coli strain and named as bovine-EN and bovine-EG. Based on the sequence of ibeB gene of meningitic Escherichia coli K1 RS218 strain in GenBank, a pair of primers was designed and the ibeB gene was cloned from isolates by PCR. Part molecular biology information of ibeB among different strains was compared. Results: The sequence length of isolates ibeB gene was 1500 bp, containing a 1371 bp open reading frame (ORF) encoding 457 amino acids. Bioinformatics analysis showed that the nucleotide and amino acid homology of ibeB gene of bovine-EN strain shared 90.5% and 96.9% identity with Escherichia coli K1 RS218 ibeB gene, respectively, while bovine-EG strain shared 99.4% and 100.0% identity with Escherichia coli K12 respectively. The ibeB gene of bovine-E strains encoded water-soluble protein whose molecular weight was 50.26 kDa and isoelectric point was 6.05. This protein contained a signal peptide A but no transmembrane domain. Subcellular localization of ibeB belonged to the secreted protein, which secretory signal path site (SP) proportion was 0.939. Conclusion: The ibeB gene was cloned from meningitic E. coli isolates and had higher homology and similar biological characteristics with meningitis E. coli K1 RS218ibeB, which belongs to extraintestinal pathogenic Escherichia coli.

Long-term survival in a dog with meningoencephalitis and epidural abscessation due to Actinomyces species.

A 2-year-old, female spayed Golden Retriever dog was presented to The Ohio State University Veterinary Medical Center for evaluation of ataxia, cervical pain, 1 episode of acute collapse, dull mentation, and inappetence. Physical examination revealed an elevated temperature of 39.7°C and severe cervical pain. Blood work revealed a mature neutrophilia. Cerebrospinal fluid (CSF) analysis revealed nondegenerative neutrophilic pleocytosis with no infectious agents. A presumptive diagnosis of steroid-responsive meningitis-arteritis was made, and corticosteroid therapy was started. The patient improved initially but experienced a vestibular episode characterized by falling and vertical nystagmus. A magnetic resonance imaging of the brain revealed an epidural abscess in the cervical vertebral canal and diffuse meningeal enhancement in the brain and cranial cervical spine. Abscess drainage revealed degenerate neutrophils and several filamentous, branching organisms. Culture of the initial CSF using an enrichment broth revealed growth of a Gram-positive organism 5 days after fluid collection. The isolate was identified by partial 16S ribosomal DNA sequencing as Actinomyces spp. The patient was successfully treated with long-term antibiotics. Our study reports the long-term survival after medical treatment of bacterial meningoencephalitis and epidural abscessation due to Actinomyces sp. infection in a dog. Bacterial meningoencephalitis should be included as a differential diagnosis in patients with cervical pain and fever, even when a nondegenerative neutrophilic pleocytosis is found on CSF analysis. Culture of the CSF with use of an enrichment broth should be considered in all cases of neutrophilic pleocytosis to rule out infections of the central nervous system.

Focal bacterial meningitis following ascending bite wound infection leading to paraparesis in a captive California sea lion (Zalophus californianus).

Magnetic resonance imaging was performed on a 15-yr-old captive female California sea lion (Zalophus californianus) with a 2-wk history of progressive paraparesis and a 9-mo history of exudative skin lesion on the left thoracic wall. Magnetic resonance images showed a well-defined muscle infiltrating lesion ventrolateral to the seventh cervical to the third thoracic vertebra on the left side, which extended through the left intervertebral foramina C7 to T3 into the vertebral canal, causing spinal cord compression and displacement as well as inflammation of the spinal cord and nerves. This lesion surprisingly caused no forelimb deficits. Differential diagnoses included abscess formation or neoplasia. Pathologic examination revealed chronic focal purulent meningitis associated with widespread paraspinal fistulous inflammation originating from a chronic dermal ulcer. Mainly Escherichia coli var. haemolytica and Clostridium perfringens were identified as the underlying agents.

Host-pathogen Interaction at the Intestinal Mucosa Correlates With Zoonotic Potential of Streptococcus suis.

BACKGROUND: Streptococcus suis has emerged as an important cause of bacterial meningitis in adults. The ingestion of undercooked pork is a risk factor for human S. suis serotype 2 (SS2) infection. Here we provide experimental evidence indicating that the gastrointestinal tract is an entry site of SS2 infection. METHODS: We developed a noninvasive in vivo model to study oral SS2 infection in piglets. We compared in vitro interaction of S. suis with human and porcine intestinal epithelial cells (IEC). RESULTS: Two out of 15 piglets showed clinical symptoms compatible with S. suis infection 24-48 hours after ingestion of SS2. SS2 was detected in mesenteric lymph nodes of 40% of challenged piglets. SS2 strains isolated from patients showed significantly higher adhesion to human IEC compared to invasive strains isolated from pigs. In contrast, invasive SS9 strains showed significantly higher adhesion to porcine IEC. Translocation across human IEC, which occurred predominately via a paracellular route, was significantly associated with clonal complex 1, the predominant zoonotic genotype. Adhesion and translocation were dependent on capsular polysaccharide production. CONCLUSIONS: SS2 should be considered a food-borne pathogen. S. suis interaction with human and pig IEC correlates with S. suis serotype and genotype, which can explain the zoonotic potential of SS2.