Emergence of Capnocytophaga canimorsus and Capnocytophaga cynodegmi in oral cavities of newborn puppies, a pilot study.

Capnocytophaga canimorsus and Capnocytophaga cynodegmi are commensal bacteria in the oral cavities of dogs. Both are zoonotic pathogens that could infect humans via dog bites. C. canimorsus may cause life-threatening infections in humans, whereas C. cynodegmi infections tend to be milder and more localized. Capsular serovars A-C of C. canimorsus seem to be virulence-associated. Some of the C. canimorsus serovars described to date can also be detected in other Capnocytophaga species, including C. cynodegmi. The objective of this pilot study was to investigate the emergence of C. canimorsus and C. cynodegmi after birth in oral cavities of puppies and to evaluate the impact of the dam's Capnocytophaga spp. carrier status on the emergence. Ten litters, altogether 59 puppies, were included in the study. The puppies and their dams were sampled at five time points over seven weeks after whelping. Oral swab samples taken were investigated for the presence of C. canimorsus and C. cynodegmi by species-specific polymerase chain reaction (PCR), the specificity of which was verified by sequencing a selection of the PCR products. Samples that were positive in Capnocytophaga PCR reactions were also capsular-typed by PCR to gain more knowledge about the Capnocytophaga spp. present in the samples. Altogether 10.2% and 11.9% of puppies, or 20.0% and 30.0% of litters tested PCR-positive for C. canimorsus and C. cynodegmi, respectively. Capnocytophaga PCR-positive puppy samples were always positive for only C. cynodegmi or C. canimorsus, not both. Most Capnocytophaga PCR-positive puppies became positive at the age of 5 to 7 weeks. Only a minority (5/16) of the C. cynodegmi PCR-positive dog samples were positive in capsular typing PCR, whereas all C. canimorsus PCR-positive dog samples were negative in capsular typing PCR. For all Capnocytophaga PCR-positive puppies, their dam was positive for the same Capnocytophaga species. These results suggest that puppies become colonized by C. cynodegmi or C. canimorsus from their dams at the time of deciduous teeth eruption.

Sudden Vision Loss as the First Sign of Sepsis-Bilateral Endogenous Endophthalmitis of Uncommon Capnocytophaga canimorsus Etiology.

We present a case of bilateral endogenous endophthalmitis with an extremely rare etiology of Capnocytophaga canimorsus. A 42-year-old asplenic patient with bilateral deterioration of visual acuity presented to the Emergency Department. The sudden deterioration of visual acuity, which prompted the patient to visit the ophthalmologist, was the first sign of the onset of sepsis. The physicians' attention, in addition to poor visual acuity and intense inflammation on ophthalmologic examination, was drawn to the reported flu-like symptoms. They were accompanied by high C-reactive protein results and abnormalities in echocardiography. A blood culture isolated the bacterium Capnocytophaga canimorsus. Immunocompromised patients are particularly susceptible to C. canimorsus infection. Endophthalmitis of this etiology has a very aggressive course, both ophthalmic and systemic. Therefore, quick diagnosis and initiation of adequate therapy are crucial.

Capnocytophaga periodontitidis sp. nov., isolated from subgingival plaque of periodontitis patient.

Two carbon dioxide-requiring, gliding, Gram-stain-negative strains, designated p1a2T and 051621, were isolated from subgingival plaque in association with severe periodontitis. The 16S rRNA gene sequence analysis revealed that they represented members of the genus Capnocytophaga and had less than 96.4 % pairwise similarity with species with validly published names in this genus. The whole-genome sequences of those strains had less than 91.9 % average nucleotide identity and 48.4 % digital DNA-DNA hybridization values with the other type strains of species of the genus Capnocytophaga, both below the species delineation threshold. The results of pan-genomic analysis indicated that p1a2T and 051621 shared 765 core gene families with the other ten species in this genus, and the numbers of strain-specific gene families were 493 and 455, respectively. The major fatty acids were iso-C15 : 0 and C16 : 0. A combination of phenotypic, chemotaxonomic, phylogenetic and genotypic data clearly indicate that p1a2T and 051621 should be considered to represent a novel species of the genus Capnocytophaga, for which the name Capnocytophaga periodontitidis sp. nov. is proposed. The type strain is p1a2T (=CGMCC 1.17337T=JCM 34126T).

Microbiología de las infecciones causadas por mordeduras de perros y gatos en personas: una revisión / Microbiology of infections caused by dog and cat bites: a review

INTRODUCCIÓN: Las mordeduras causadas por animales de compañía constituyen el 5% de las heridas traumáticas registradas en los servicios de urgencias. OBJETIVO: Conocer los principales agentes infecciosos presentes en las mordeduras provocadas por perros y gatos, tanto de forma individual como conjunta; así como los factores que favorecen la infección. METODOLOGÍA: Se realizó una búsqueda bibliográfica en Pub-Med con la siguiente estrategia de búsqueda: (("Bites, Human"[Mesh]) OR "Bites and Stings"[Mesh]) AND "Infection"[Mesh]. Se incluyeron 24 trabajos en la síntesis cualitativa escritos en lengua inglesa o española, casos clínicos o descriptivos y publicados entre los años 2000 y 2019. RESULTADOS: Las especies más frecuentemente aisladas fueron Capnocytophaga canimorsus en perros y Pasteurella multocida en gatos. La existencia de comorbilidades en el individuo, la mordedura en la mano, o la presencia de signos de alteración del estado general del individuo mordido fueron considerados como factores de riesgo para el desarrollo de la infección tras la mordedura. CONCLUSIONES: Todos los afectados por mordeduras animales deben recibir asistencia médica y considerar la administración de una pauta de profilaxis antimicrobiana con el fin de reducir el riesgo de shock séptico. Por otro lado, es importante advertir al laboratorio de microbiología de la naturaleza de las muestras clínicas obtenidas para alcanzar el mejor diagnóstico etiológico.

BACKGROUND: Bites caused by pets constitute 5% of the traumatic injuries registered in the emergency services. AIM: To know the main infectious agents present in dog and cat bites, both individually and jointly, in humans, as well as the predisposing factors that favor infection and its spread. METHODS: A bibliographic search was carried out in PubMed with the following search strategy: (("Bites, Human" [Mesh]) OR "Bites and Stings" [Mesh]) AND "Infection" [Mesh]. Twenty-four papers were included in the qualitative synthesis written in English or Spanish, clinical or descriptive cases and published between 2000 and 2019. Results: Most frequently isolated species were Capnocytophaga canimorsus in dogs and Pasteurella multocida in cats. The existence of comorbidities in the individual, the bite on the hand, or the presence of signs of alteration of the general state of the bitten individual were considered as risk factors for the development of infection after the bite. CONCLUSIONS: All patients with animal bites should receive medical assistance, and the administration of an antibiotic prophylaxis regimen should be considered to reduce the risk of septic shock. Besides, it is important to advise the microbiology laboratory of the nature of the clinical samples obtained in order to reach the best etiological diagnosis.

Bilateral acute renal cortical necrosis after a dog bite: case report.

BACKGROUND: Capnocytophaga canimorsus is a Gram-negative capnophilic rod and part of dogs/cats' normal oral flora. It can be transmitted by bites, scratches, or even by contact of saliva with injured skin. Asplenic patients and patients with alcohol abuse are at particular risk for fulminant C. canimorsus sepsis. However, also immunocompetent patients can have a severe or even fatal infection. This is the first case of a severe C. canimorsus infection in an immunocompromised host complicated by acute renal cortical necrosis with a "reverse rim sign" in contrast-enhanced computed tomography on hospital admission. CASE PRESENTATION: We report the case of a 44-year functionally asplenic patient after an allogeneic stem cell transplantation, who presented with septic shock after a minor dog bite injury 4 days prior. Because of abdominal complaints, epigastric pain with local peritonism, and radiological gallbladder wall thickening, an abdominal focus was suspected after the initial work-up. The patient underwent emergent open cholecystectomy, but the clinical suspicion of abdominal infection was not confirmed. Septic shock was further complicated by cardiomyopathy and disseminated intravascular coagulation. As a causative pathogen, C. canimorsus could be isolated. The clinical course was complicated by permanent hemodialysis and extensive acral necrosis requiring amputation of several fingers and both thighs. CONCLUSION: We present a severe case of a C. canimorsus infection in a functionally asplenic patient after a minor dog bite. The clinical course was complicated by septic shock, disseminated intravascular coagulation, and the need for multiple amputations. In addition, the rare form of acute renal failure - bilateral acute renal cortical necrosis - was visible as "reverse rim sign" on computed tomography scan. This case is an example of the potential disastrous consequences when omitting pre-emptive antibiotic therapy in wounds inflicted by cats and dogs, particularly in asplenic patients.

Comparative analysis of oral microbiome from Zang and Han populations living at different altitudes.

OBJECTIVES: The aim of this study was to obtain greater insight into the environmental and genetic factors affecting the oral microbiome. DESIGN: To this end, we investigated the oral microbiome composition in Han and Zang populations living at different altitudes. The saliva microbiome in 115 individuals from Zang and Han populations living at different altitudes was analyzed using the 16 s rRNA gene sequencing method on the Illumina MiSeq platform. The dominant species in the oral microbiome were verified by quantitative real-time polymerase chain reaction (qPCR) analysis. RESULTS: The Han population, living at an altitude of 500 m, had higher microbiome diversity than the Zang population living at altitudes of 3000-4000 m. People living at 3000 m had a higher relative abundance of Leptothrix genus, but people living at 500 m had a higher relative abundance of Capnocytophaga genus according to Lefse difference analysis (P < 0.05). Compared to the Zang population, the Han population had higher relative abundances of Porphyromonas and Treponema genus organisms, especially Porphyromonas (P < 0.001). qPCR analysis confirmed that people living at high altitudes had the highest relative abundance of Porphyromonas gingivalis (P < 0.01). CONCLUSIONS: This study showed that both genetics and the environment had significant influences on the oral microbiome composition. The study proposed a meaningful research direction to explore the relationship between different ethnic and altitude groups and oral diseases, such as periodontal diseases.

Capnocytophaga sputigena bloodstream infection in hematopoietic stem cell transplantations: two cases report and review of the literature.

Capnocytophaga is a group of facultative anaerobic gram-negative bacteria present in the oral cavity of humans, dogs and cats, as part of their normal oral flora. Here, we described two cases of bloodstream infections (BSI) caused by Capnocytophaga in neutropenic autologous hematopoietic stem cell transplantation (auto-HSCT) patients with mucositis (Grade I and Grade III) identified by Maldi-Tof. They were successfully treated with ß-lactam (meropenem and piperacillin-tazobactam). The species C. sputigena was confirmed by 16S rRNA gene sequencing in one patient. The review of literature showed that C. ochraceae was the most frequent species causing BSI in auto-HSCT patients and that the patients usually presented mucositis and were neutropenic at the onset of the infection.

Capnocytophaga felis sp. nov. isolated from the feline oral cavity.

Four strains, KC07070T, KC07105, 11 025B-8C and 11 026B-8-C, were isolated from the oral cavity of cats in 2007 or 2011 in Japan. These strains were Gram-stain-negative rods, exhibited gliding motility, grew in air with 5 % CO2 and showed catalase and oxidase activity. The sequences of 16S rRNA genes of the four strains were 100 % identical. Additionally, the sequences of 16S rRNA genes of KC07070T had identity to those of the type strains of Capnocytophaga canimorsus (97.7 %), Capnocytophaga cynodegmi (97.8 %) and Capnocytophaga canis (97.4 %) and 91.2-93.8% identity to those of other species of the genus Capnocytophaga. The major cellular fatty acids of KC07070T were iso-C15 : 0 (56.2 %) and summed feature 11 (14.9 %). The G+C content of the DNA from KC07070T was 35.6 mol%, and the genome size was 2.88 Mbp. KC07070T had digital DNA-DNA hybridization (dDDH) values of 26.2-27.6% and average nucleotide identity (ANI) values of 75.4-83.3 % to the type strains of the closest relatives, C. canimorsus, C. cynodegmi and C. canis. These results of phylogenetic analysis of 16S rRNA gene sequence, cellular fatty acids compositions and dDDH and ANI values indicate that strain KC07070T represents a novel species, for which we propose the name Capnocytophaga felis sp. nov., with type strain KC07070T (=JCM 32681T=DSM 107251T).

An oral health optimized diet reduces the load of potential cariogenic and periodontal bacterial species in the supragingival oral plaque: A randomized controlled pilot study.

This study aimed to investigate the effects of an oral health optimized diet on the composition of the supragingival oral plaque in a randomized controlled trial. Participants of the standard diet group (n = 5) had a diet high in processed carbohydrates and did not change their dietary behavior during the observation. The healthy diet group (n = 9) had to change the diet after 2 weeks from a diet high in processed carbohydrates to a diet low in carbohydrates, rich in omega-3 fatty acids, rich in vitamins C and D, antioxidants and fiber for 4 weeks. Saliva and supragingival plaque samples were taken at the end of week two and eight of the observation period to investigate the composition of microbiota in saliva and supragingival plaque. Data were subjected to an exploratory analysis to identify significant differences. Statistically significant differences were only found in the healthy diet group between the baseline (week 2) and the final sample (week 8) for specific species in plaque and saliva samples. A reduction of the total counts of Streptococcus mitis group, Granulicatella adiacens, Actinomyces spp., and Fusobacterium spp. was found in plaque samples of the healthy diet group. In saliva samples of the healthy diet group, the total counts of Actinomyces spp. and Capnocytophaga spp. decreased. A diet low in carbohydrates, rich in omega-3 fatty acids, rich in vitamins C and D, and rich in fiber reduced Streptococcus mitis group, Granulicatella adiacens, Actinomyces spp., and Fusobacterium spp. in the supragingival plaque.

Septic shock caused by Capnocytophaga canis after a cat scratch.

Capnocytophaga canis is an uncommon cause of septic shock. Only three cases have been previously reported in the literature. In this article, we describe the case of a 70-year-old male admitted to the intensive care unit for septic shock of unknown origin. On day 2, one anaerobic bottle out of the two sets taken at admission turned positive with Gram-negative bacilli. The pathogen was identified by 16S rRNA gene as C. canis. The strain was characterized and compared with other clinical isolates of Capnocytophaga spp.

Unexpected pathogen presenting with purulent meningitis.

Herein we report a case of a 67-year-old man with chronic lymphocytic leukaemia who developed acute onset of fever and altered mental status while receiving ibrutinib therapy. He was eventually found to have Capnocytophaga canimorsus meningitis. Timely diagnosis and appropriate antimicrobial therapy was associated with a favourable outcome. We describe challenges associated with appropriate identification of, and briefly review infections caused by Capnocytophaga sp. To our knowledge, this is the first case of invasive C. canimorsus infection in the setting of ibrutinib therapy, and adds to the growing list of serious infections that have been associated with this agent.

A case of Capnocytophaga canimorsus meningitis and bacteraemia.

Capnocytophaga canimorsus is a commonly detectable commensal in the oral flora of dogs and cats, found in 25.5% and 15%, respectively, by culture and 70% and 55%, respectively, by molecular methods [1]. Formerly known as dysgonic fermenter 2 (DF-2), it was first reported in 1976 as a Gram-negative bacillus causing septicaemia and meningitis following dog bites [2]. It causes a spectrum of clinical syndromes from wound infections to bacteraemia and meningitis, especially in those with hyposplenism and alcoholism. We report a case of C. canimorsus meningitis and bacteraemia, and give a review of the relevant literature.

CAPNOCYTOPHAGA CANIMORSUS ENDOPHTHALMITIS AFTER CATARACT SURGERY LINKED TO SALIVARY DOG-TO-HUMAN TRANSMISSION.

PURPOSE: To describe a case of acute postoperative bacterial endophthalmitis because of Capnocytophaga canimorsus after cataract surgery, with probable contamination through salivary droplets of dog two days after the procedure. METHODS: An 83-year-old woman who underwent uncomplicated cataract extraction with intraocular lens implantation, presented 12 days later with acute pain, redness, and vision loss in her left eye. Visual acuity was hand motion and clinical findings suggested the diagnosis of acute postoperative endophthalmitis. The patient underwent diagnostic vitrectomy, intravitreal ceftazidime/vancomycin injection and received oral moxifloxacin (400 mg/day). Two days later, she underwent complete pars-plana vitrectomy because of the absence of clinical improvement. Vitreous samples showed gram-negative bacterium on direct examination but cultures remained sterile, which prompted the realization of a broad-range bacterial polymerase chain reaction analysis. RESULTS: Polymerase chain reaction on the vitreous sample detected C. canimorsus, a fastidious gram-negative bacterium of the oral canine flora. When asked for recent contact with dogs, the patient reported having proceeded to an intensive tooth care session for her dog at postoperative Day 2. Intravenous ceftriaxone (2 g/day) was added to the treatment. Anterior and posterior segment inflammation slowly resolved, and final visual acuity was 20/160. CONCLUSION: Although very rare, this complication suggests that patients undergoing ocular surgery should avoid contact with salivary secretions of pets during the early postoperative period. Diagnostic broad-range bacterial polymerase chain reaction is useful to detect unconventional or slow-growing agents in vitreous samples.

Beware of the dog! Septic shock due to Capnocytophaga canimorsus revealed on peripheral blood smear.

A blood smear examination led to the diagnosis of severe bacterial infection in a splenectomized patient. The knowledge of a relevant clinical information (recent dog bite) could have led to immediate presumptive identification of the causative agent, Capnocytophaga canimorsus.

Beware of the dog - Capnocytophga Canimorsus septic shock: a case report.

Capnocytophaga canimorsus is a Gram-negative rods frequently isolated as commensal in the saliva of pets that can be transmitted to humans. We report a case of septic shock caused by this pathogen. A 78-year-old man affected by diabetes and hypertension was admitted for fever in our Emergency Department. He reported fever (37.7°C) with normal values of blood pressure, heart rate and saturation of oxygen. Laboratory studies showed increased values of procalcitonin and normal white-cell level. Blood cultures were collected and an empirical antibiotic therapy was started. He reported six days earlier a bite of a dog at the right hand. During the following days the patient presented a deterioration of clinical conditions with fever, asthenia and comparison of petechial lesions. C. canimorsus was isolated from blood cultures. He was treated with fluids and appropriate antibiotic therapy with a full recovery. Dog wounds are frequent minor injuries with an underestimated worldwide incidence because only few patients develop complications. C. canimorsus could be an emerging cause of sepsis, also in immunocompetent patients. The current understanding of risk factors for C. canimorsus associated sepsis and a prompt approach to anamnesis and treatment of early stage injuries, could have a considerable medical outcome.

Rapid diagnosis of Capnocytophaga canimorsus septic shock in an immunocompetent individual using real-time Nanopore sequencing: a case report.

BACKGROUND: Rapid diagnosis and appropriate treatment is imperative in bacterial sepsis due increasing risk of mortality with every hour without appropriate antibiotic therapy. Atypical infections with fastidious organisms may take more than 4 days to diagnose leading to calls for improved methods for rapidly diagnosing sepsis. Capnocytophaga canimorsus is a slow-growing, fastidious gram-negative bacillus which is a common commensal within the mouths of dogs, but rarely cause infections in humans. C. canimorsus sepsis risk factors include immunosuppression, alcoholism and elderly age. Here we report on the application of emerging nanopore sequencing methods to rapidly diagnose an atypical case of C. canimorsus septic shock. CASE PRESENTATION: A 62 year-old female patient was admitted to an intensive care unit with septic shock and multi-organ failure six days after a reported dog bite. Blood cultures were unable to detect a pathogen after 3 days despite observed intracellular bacilli on blood smears. Real-time nanopore sequencing was subsequently employed on whole blood to detect Capnocytophaga canimorsus in 19 h. The patient was not immunocompromised and did not have any other known risk factors. Whole-genome sequencing of clinical sample and of the offending dog's oral swabs showed near-identical C. canimorsus genomes. The patient responded to antibiotic treatment and was discharged from hospital 31 days after admission. CONCLUSIONS: Use of real-time nanopore sequencing reduced the time-to-diagnosis of Capnocytophaga canimorsus in this case from 6.25 days to 19 h. Capnocytophaga canimorsus should be considered in cases of suspected sepsis involving cat or dog contact, irrespective of the patient's known risk factors.

Capnocytophaga canimorsus peritonitis diagnosed by mass spectrometry in a diabetic patient undergoing peritoneal dialysis: a case report.

BACKGROUND: Bacterial peritonitis is a serious complication of patients undergoing peritoneal dialysis (PD). Although the identification of causative organisms and use of appropriate antibiotics are essential for treatment, rare and fastidious bacteria are sometimes difficult to detect by conventional biochemical assays. Capnocytophaga canimorsus is a fastidious and slow-growing bacterium that forms a part of the normal oral flora of dogs and cats and is extremely rare as a peritonitis-causing organism. This report demonstrates the usefulness of a mass spectrometry-based technique in identifying such a rare organism in PD-related peritonitis and discusses the diagnosis and treatment of C. canimorsus peritonitis. CASE PRESENTATION: A 49-year-old woman with type 2 diabetes mellitus underwent PD for two years. Repeated exit-site infections led to subcutaneous pathway diversion two months ago. She was hospitalized with fever and abdominal pain as well as cloudy dialysis effluent. Laboratory data revealed increased serum C-reactive protein level and white blood cell (WBC) count in the effluent. Her exit site had no sign of infection, leading to the diagnosis of PD-related peritonitis. Initial therapy with intraperitoneal ceftazidime immediately ameliorated her symptoms, and the WBC count in the effluent normalized in five days. Culture test results of the dialysis effluent on admission were negative with no information regarding the infection route. However, mass spectrometry (MALDI Biotyper, Bruker Daltonics) successfully obtained the specific spectral pattern for C. canimorsus. She had four cats in her house and was advised not to allow the cats in the room where the bag exchange took place. CONCLUSIONS: C. canimorsus is a rare cause of peritonitis in PD patients and is usually susceptible to intraperitoneal third-generation cephalosporins. This mass spectrometry-based bacterial identification method could provide more opportunities to identify uncommon causes and promote appropriate antibiotics therapy in PD-related peritonitis.