25 April 2025: Articles
from Dog Saliva Exposure Causing Severe Sepsis in a Healthy Adult: A Case Report
Unusual clinical course, Challenging differential diagnosis
Megan A. Stephens1DEF, Nawras Silin2ABDE*, Tahani Dakkak1ADEF, Sangamithra Sathian2F, Aditya K. Ghosh

DOI: 10.12659/AJCR.946691
Am J Case Rep 2025; 26:e946691
Abstract
BACKGROUND: Capnocytophaga canimorsus is a gram-negative bacterium commonly found in the saliva of dogs and cats. It has the ability to evade the human immune system and cause life-threatening infections, particularly in immunocompromised individuals. C. canimorsus infection was first described in 1976, and additional cases have since been reported, with complications varying from mild to severe. This case report highlights the occurrence of a severe C. canimorsus infection in an immunocompetent patient, which rapidly progressed to septic shock and multiorgan failure.
CASE REPORT: We present the case of a 63-year-old man with no significant past medical history who presented with weakness, fatigue, and confusion. Further investigation revealed a wound on his lower right extremity, which had been licked by his dog. The causative pathogen was identified as C. canimorsus through blood culture and mass spectrometry. The patient experienced septic shock with multiorgan failure, including acute renal failure, liver failure, and coagulopathy. Prompt initiation of empirical broad-spectrum antibiotics prior to identification of the source of infection proved to be beneficial, resulting in clinical and symptomatic improvement for the patient.
CONCLUSIONS: This case emphasizes the severe complications that can arise from C. canimorsus infection in immunocompetent individuals, underscoring the importance of early recognition and treatment in cases of sepsis, particularly in those with potential dog saliva exposure.
Keywords: Capnocytophaga, Saliva, Sepsis
Introduction
In some cases,
Infections caused by
Previous reports have documented septic shock and multi-system organ failure in immunocompromised patients following
Case Report
A 63-year-old man with no significant medical history presented to the Emergency Department with symptoms of weakness, confusion, neck pain, joint pain, low back pain, and pain in the proximal thighs. He was accompanied by his wife, and they reported that symptoms had started 2 days prior. Despite a prior visit to the Emergency Department and discharge with medications for muscular spasm, his condition worsened significantly within the following 12 h. Notably, his weakness progressed to the point where he was unable to lift his legs, walk, or stand without assistance. During this time, he denied experiencing increased weakness in his upper extremities. Furthermore, he denied fever, headaches, visual changes, chest pain, shortness of breath, gastrointestinal symptoms, urinary symptoms, and sensory changes.
Upon evaluation, his vital signs revealed a respiratory rate of 30 breaths per min and blood pressure of 100/45 mm Hg. He had no fever, and his oxygen concentration was normal. Electrocardiography revealed normal sinus rhythm, with a rate of 87 beats per min, and no acute ischemic changes. Laboratory findings revealed significant abnormalities, including elevated levels of blood urea nitrogen at 52 mg/dL and serum creatinine at 4.42 mg/dL, indicating impaired renal function. Liver function tests revealed significantly elevated levels of aspartate transaminase >6000 U/L and alanine transaminase at 3928 U/L, consistent with liver damage. Additional findings included white blood cell count of 8.4 K/μL, with 55% bands, lactate level of 5.5 mmol/L, and platelet count of 31 K/μL, confirming the diagnosis of severe sepsis. Additionally, the DIC profile revealed a prothrombin time of 21.9 s, D-dimer greater than 4000 μg/mL, and fibrinogen of 99 mg/dL (Table 1).
Imaging studies revealed left lower lobe pneumonia, persistent bilateral nephrograms, concerning for acute tubular necrosis without hydronephrosis or perinephric fluid collection, and mild hepatomegaly (Figure 1). Neurology consultation led to a diagnosis of inflammatory and immune myopathies, for which the patient was initiated on intravenous immunoglobulin and methylprednisolone, leading to symptomatic improvement. Additional imaging, including magnetic resonance imaging of the brain and spine and a pan computed tomography scan, was recommended to rule out malignancy.
The patient was admitted to the Intensive Care Unit (ICU) for the treatment of septic shock, thrombocytopenia, renal dysfunction, and liver failure. He received aggressive resuscitation with intravenous fluids and vasopressors. Broad-spectrum antibiotics were also initiated empirically for septic shock. The antibiotic course included ampicillin and acyclovir on day 1, vancomycin day 2 to day 4, meropenem day 2 to day 8, doxycycline day 2 to day 8, and micafungin day 3 to day 7.
Additionally, an autoimmune workup, including tests for anti-nuclear antibody, anti-smooth muscle antibody, and ganglioside antibodies (GQ1b IgG and IgM, GD1b IgG and IgM), was done and yielded negative results. C-reactive protein level was elevated at 22.5 mg/dL, and ADAMTS13 activity was reduced to 30%. However, blood cultures returned positive for gram-negative rods (Figure 2), later identified as
The broad-spectrum antibiotic regimen for septic shock, although nonspecific, effectively covered the bacterial infection and was discontinued on day 8. The Infectious Disease Department was consulted and subsequently started the patient on intravenous ampicillin/sulbactam on day 9, continuing until day 15, one day before discharge. The targeted antibiotic for
Nephrology consultation was sought due to acute kidney injury, which necessitated continuous renal replacement therapy, and the patient was later transitioned to hemodialysis.
The Nephrology Department continued to monitor the patient throughout the hospital course. Additionally, the patient received a diagnosis of DIC and shock liver, for which he received platelet transfusions, N-acetylcysteine infusion, and cryoprecipitate, resulting in clinical and laboratory improvement. Thrombocytopenia improved, with full resolution prior to discharge.
The patient demonstrated significant clinical improvement throughout the hospital course. His blood pressure readings stabilized to the 120s to 150s systolic and 70s to 90s diastolic. Confusion resolved on day 5. Fatigue and weakness improved throughout the hospital course, and he was able to ambulate on day 11. Physical therapy interventions resulted in significant functional improvement, as evidenced by an Activity Measure for Post-Acute Care score of 23 of 24.
He underwent vascular surgery consultation for the exchange of his temporary hemodialysis catheter to a tunneled catheter. Upon discharge on day 16, the patient continued outpatient hemodialysis 3 times per week. He was advised to follow up with nephrology and primary care physicians within 1 to 2 weeks. Approximately 1 month after discharge, the patient continued to require hemodialysis 3 times per week. He still reported residual generalized weakness and fatigue, although significantly improved from before.
Discussion
From this case report, we learn that
Furthermore, individuals with splenectomies comprise 60% of
The typical incubation period of
This case report highlights the complexities involved in diagnosing
Conclusions
Our patient presented with systemic symptoms and was later found to have septic shock with end-stage organ failure due to
Figures
References:
1.. Suzuki M, Kimura M, Imaoka K, Yamada A: Vet Microbiol, 2010; 144(1–2); 172-76
2.. Mantovani E, Busani S, Biagioni E: Case Rep Crit Care., 2018; 2018; 7090268
3.. , About capnocytophaga: Capnocytophaga May 9, 2024 Accessed June 6, 2024. Available from: https://www.cdc.gov/capnocytophaga/about/index.html
4.. Talan DA, Citron DM, Abrahamian FM, Bacteriologic analysis of infected dog and cat bites. Emergency Medicine Animal Bite Infection Study Group: N Engl J Med, 1999; 340(2); 85-92
5.. Shin H, Mally M, Meyer S: Infect Immun, 2009; 77(6); 2262-71
6.. Mally M, Shin H, Paroz C, Landmann R, Cornelis GR: PLoS Pathog., 2008; 4(9); e1000164
7.. Shin H, Mally M, Kuhn M: J Infect Dis, 2007; 195(3); 375-86
8.. Hess E, Renzi F, Koudad D: J Clin Microbiol, 2017; 55(6); 1902-14
9.. Renzi F, Ittig SJ, Sadovskaya I: Sci Rep, 2016; 6(1); 38914
10.. , Clinical overview of capnocytophaga: Capnocytophaga June 4, 2024 Accessed June 12, 2024. Available from: https://www.cdc.gov/capnocytophaga/hcp/clinical-overview/index.html
11.. Chesdachai S, Tai DBG, Yetmar ZA, The characteristics of capnocytophaga infection: 10 years of experience.: Open Forum Infect Dis, 2021; 8(7) ofab175
12.. Pers C, Gahrn-Hansen B, Frederiksen W: Clin Infect Dis, 1996; 23(1); 71-75
13.. Meyer EC, Alt-Epping S, Moerer O, Büttner B: BMC Infect Dis., 2021; 21(1); 736
14.. , Capnocytophaga spp. | Johns Hopkins ABX Guide. Accessed June 17, 2024. Available from: https://www.hopkinsguides.com/hopkins/view/Johns_Hopkins_ABX_Guide/540078/all/Capnocytophaga_spp_?refer=true
15.. Nakayama R, Miyamoto S, Tawara T: Acute Med Surg., 2022; 9(1); e738
16.. Janda JM, Graves MH, Lindquist D, Probert WS: Emerg Infect Dis., 2006; 12(2); 340-42
17.. Hästbacka J, Hynninen M, Kolho E: Acta Anaesthesiol Scand, 2016; 60(10); 1437-43
18.. Sardo S, Pes C, Corona A: J Public Health Res, 2022; 11(4) 22799036221133234
19.. Ahsen A, Korsun P, Albahra F: Case Rep Infect Dis., 2023; 2023; 9917898
20.. Lion C, Escande F, Burdin JC: Eur J Epidemiol, 1996; 12(5); 521-33
21.. Mader N, Lührs F, Langenbeck M, Herget-Rosenthal S: Infect Dis (Lond), 2020; 52(2); 65-74
22.. Hansen M, Crum-Cianflone NF: Infect Dis Ther, 2019; 8(1); 119-36
23.. Jolivet-Gougeon A, Sixou JL, Tamanai-Shacoori Z, Bonnaure-Mallet M, Antimicrobial treatment of Capnocytophaga infections: Int J Antimicrob Agents, 2007; 29(4); 367-73
24.. Sandoe JAT: J Med Microbiol, 2004; 53(Pt 3); 245-48
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