Pasteurella multocida infection in a cirrhotic patient: case report, microbiological aspects and a review of literature

A bite difficult to heal: Pasteurella multocida induced decompensated hepatic cirrhosis

Pasteurella multocida is a gram-negative bacterium that colonizes domestic animals. It is commonly implicated in bite and scratch wounds, potentially resulting in cellulitis, superficial abscesses, osteomyelitis, or peritonitis. Rarely, it can lead to bacteremia and septic shock in high-risk patients. We present an atypical presentation of Pasteurella multocida bacteremia and sepsis in a patient with stage 4 decompensated cirrhosis. The patient presented with melena and altered mental status with CT imaging showing a heterogeneous nodular liver along with an enlarged portal vein, gastric varices, and ascites consistent with decompensated cirrhosis. The patient was initially managed with intravenous (IV) octreotide and pantoprazole, blood and platelet transfusions, and broad-spectrum antibiotics. Upper endoscopy showed diffuse non-bleeding esophageal and gastric varices, which required band ligation and continued IV octreotide therapy. The infection resolved after a 7-day course of IV ceftriaxone.

Pasteurella bacteraemia: Impact of comorbidities on outcome, based on a case series and literature review

OBJECTIVES

Pasteurella bacteraemia is rare, but has been associated with a high mortality rate. The aim of this study was to estimate the impact of comorbidities on patients with Pasteurella bacteraemia.

METHODS

All cases of Pasteurella bacteraemia in adults treated in our centre between January 2008 and December 2017 were included retrospectively and compared with cases identified in a systematic review of the literature via MEDLINE covering the years 1951-2017. The epidemiological, bacteriological, and clinical data were collected, as well as the instances of death after 30 days.

RESULTS

Twenty cases of Pasteurella bacteraemia identified in our centre and 99 cases from the literature review were included. A major comorbidity was found in 80/119 (67.2%) patients. The death rate at 30 days was 31.1%. The most common comorbidities were cirrhosis, immunosuppressive therapy, and malignant diseases. Age was not associated with mortality. On multivariate analysis, the only factor associated with mortality was a major comorbidity (odds ratio 2.78, 95% confidence interval 1.01-7.70; p = 0.04).

CONCLUSIONS

This study confirms the high mortality rate and highlights the importance of the host background, independent of age, in Pasteurella bacteraemia. Clinicians should be aware of the comorbidities in cases of Pasteurella infection, due to the poor prognosis of bacteraemia.

Pasteurella multocida: Genotypes and Genomics

Pasteurella multocida is a highly versatile pathogen capable of causing infections in a wide range of domestic and wild animals as well as in humans and nonhuman primates. Despite over 135 years of research, the molecular basis for the myriad manifestations of P. multocida pathogenesis and the determinants of P. multocida phylogeny remain poorly defined. The current availability of multiple P. multocida genome sequences now makes it possible to delve into the underlying genetic mechanisms of P. multocida fitness and virulence. Using whole-genome sequences, the genotypes, including the capsular genotypes, lipopolysaccharide (LPS) genotypes, and multilocus sequence types, as well as virulence factor-encoding genes of P. multocida isolates from different clinical presentations can be characterized rapidly and accurately. Putative genetic factors that contribute to virulence, fitness, host specificity, and disease predilection can also be identified through comparative genome analysis of different P. multocida isolates. However, although some knowledge about genotypes, fitness, and pathogenesis has been gained from the recent whole-genome sequencing and comparative analysis studies of P. multocida, there is still a long way to go before we fully understand the pathogenic mechanisms of this important zoonotic pathogen. The quality of several available genome sequences is low, as they are assemblies with relatively low coverage, and genomes of P. multocida isolates from some uncommon host species are still limited or lacking. Here, we review recent advances, as well as continuing knowledge gaps, in our understanding of determinants contributing to virulence, fitness, host specificity, disease predilection, and phylogeny of P. multocida.

Characterization of Pasteurella multocida strains isolated from human infections

Isolates of Pasteurella multocida recovered from infected humans (n = 15) were characterized by traditional and molecular microbiological methods and were compared with cat-derived strains (n = 5). The most prevalent subspecies among strains from human infections was P. multocida subsp. septica (80%), and nearly all isolates showed a similar combination of virulence-associated genes. MLST analysis classified the 20 P. multocida strains into 16 different sequence types, and we assigned 11 new sequence types (ST), however, only one of those (ST 334) was shared by two human and one cat isolates. P. multocida subsp. septica strains formed a distinct phylogenetic group within the species. The strains showed resistance to erythromycin, clindamycin and sulfamethoxazole, and with two exceptions, resistance to tilmicosin was also detected. Each strain was susceptible to ampicillin, streptomycin, gentamycin, tetracycline, doxycycline, cefazolin, cefpodoxime, chloramphenicol, florfenicol and enrofloxacin. Common characteristics (virulence profile and antibiotic sensitivity pattern) shared by strains isolated from humans and cats support the view that domestic cats may serve as a potential reservoir for P. multocida.

Infection of lung cavitations in a young dog owner with Hodgkin’s lymphoma caused by Pasteurella multocida, without a dog bite: confirmed zoonotic transmission by tagmentation microbiome analysis

Pasteurella multocida is a known pathogen in humans, mostly reported after animal bite incidents. Atraumatic infections have been described, especially in immunocompromised patients. A 20-year-old patient with a history of stage IV Hodgkin’s lymphoma with cavitating pulmonary lesions presented with a bilateral pneumonia. Shortly after finishing antibiotic treatment, she quickly developed the same symptoms of pneumonia. Bronchoscopy showed a large cavity in the right upper lobe and P. multocida was isolated from all bronchial cultures. The transmission route of P. multocida via the patient’s dog was confirmed by sampling the full genome of the dog’s mouth, which matched the unique P. multocida sequences found in the patient. This case demonstrates the importance of accurately determining the aetiology of the patient’s symptoms, and Pasteurella infection should be considered in all immunocompromised patients with domestic animal contact, even without a bite incident.

Infective Exacerbation of Pasteurella multocida

An 89-year-old lady presented with a one-day history of shortness of breath as well as a cough productive of brown sputum. Her medical history was significant for chronic obstructive pulmonary disease (COPD). She was in severe type one respiratory failure and blood tests revealed markedly raised inflammatory markers; however her chest X-ray was clear. On examination there was bronchial breathing with widespread crepitations and wheeze. She was treated as per an infective exacerbation of COPD. Subsequent blood cultures grew Pasteurella multocida, a common commensal in the oropharynx of domesticated animals. The patient was then asked about any contact with animals, after which she revealed she had a dog and was bitten on her left hand the day before admission. We should not forget to enquire about recent history of injuries or animal bites when patients present acutely unwell. She made a complete recovery after treatment with penicillin.

Bacterial infections in cirrhosis: A critical review and practical guidance

Bacterial infection is common and accounts for major morbidity and mortality in cirrhosis. Patients with cirrhosis are immunocompromised and increased susceptibility to develop spontaneous bacterial infections, hospital-acquired infections, and a variety of infections from uncommon pathogens. Once infection develops, the excessive response of pro-inflammatory cytokines on a pre-existing hemodynamic dysfunction in cirrhosis further predispose the development of serious complications such as shock, acute-on-chronic liver failure, renal failure, and death. Spontaneous bacterial peritonitis and bacteremia are common in patients with advanced cirrhosis, and are important prognostic landmarks in the natural history of cirrhosis. Notably, the incidence of infections from resistant bacteria has increased significantly in healthcare-associated settings. Serum biomarkers such as procalcitonin may help to improve the diagnosis of bacterial infection. Preventive measures (e.g., avoidance, antibiotic prophylaxis, and vaccination), early recognition, and proper management are required in order to minimize morbidity and mortality of infections in cirrhosis.

Difficult peritonitis cases in children undergoing chronic peritoneal dialysis: relapsing, repeat, recurrent and zoonotic episodes

Despite technological improvements in dialysis connectology and dialysis technique, peritonitis remains the most common and most significant complication of peritoneal dialysis (PD) in children. Most children undergoing chronic PD experience none or only one peritonitis episode, while others have multiple episodes or episodes secondary to unusual organisms. Knowledge of potential risk factors and likely patient outcome is imperative if treatment is to be optimized. In this review we will, in turn, describe episodes of peritonitis that are characterized as either relapsing, recurrent, repeat or zoonosis-related to highlight the clinical issues that are commonly encountered by clinicians treating these infections.

Pasteurella multocida Septicemia in a Patient with Cirrhosis: An Autopsy Report

More people are keeping pets in their homes but may not be sufficiently aware of the potential danger from infections. We report an autopsy case of a 57-year-old man affected by cirrhosis. Septic shock with Pasteurella multocida pneumonia was the cause of his death. P. multocida was the source of infection via the respiratory tract and caused pneumonia. Cirrhosis is one of the risk factors for P. multocida infection. A detailed patient history about animal exposure should be obtained and a differential diagnosis of P. multocida infection must be kept in mind.

Pasteurella multocida: from zoonosis to cellular microbiology

In a world where most emerging and reemerging infectious diseases are zoonotic in nature and our contacts with both domestic and wild animals abound, there is growing awareness of the potential for human acquisition of animal diseases. Like other Pasteurellaceae, Pasteurella species are highly prevalent among animal populations, where they are often found as part of the normal microbiota of the oral, nasopharyngeal, and upper respiratory tracts. Many Pasteurella species are opportunistic pathogens that can cause endemic disease and are associated increasingly with epizootic outbreaks. Zoonotic transmission to humans usually occurs through animal bites or contact with nasal secretions, with P. multocida being the most prevalent isolate observed in human infections. Here we review recent comparative genomics and molecular pathogenesis studies that have advanced our understanding of the multiple virulence mechanisms employed by Pasteurella species to establish acute and chronic infections. We also summarize efforts being explored to enhance our ability to rapidly and accurately identify and distinguish among clinical isolates and to control pasteurellosis by improved development of new vaccines and treatment regimens.

Bacterial infections other than spontaneous bacterial peritonitis in cirrhosis

Cirrhotic patients are immunocompromised with a high risk of infection. Proinflammatory cytokines and hemodynamic circulation derangement further facilitate the development of serious consequences of infections. Other than spontaneous bacterial peritonitis, bacteremia and bacterial infections of other organ systems are frequently observed. Gram-negative enteric bacteria are the most common causative organism. Other bacterial infections, such as enterococci, Vibrio spp., Aeromonas spp., Clostridium spp., Listeria monocytogenes, Plesiomonas shigelloides and Mycobacterium tuberculosis are more prevalent and more virulent. Generally, intravenous third generation cephalosporins are recommended as empirical antibiotic therapy. Increased incidences of gram-positive and drug-resistant organisms have been reported, particularly in hospital-acquired infections and in patients receiving quinolones prophylaxis. This review focuses upon epidemiology, microbiology, clinical features and treatment of infections in cirrhosis other than spontaneous bacterial peritonitis, including pathogen-specific and liver disease-specific issues.

Cat induced Pasteurella multocida peritonitis in peritoneal dialysis: a case report and review of the literature

A 7-year-old girl treated with peritoneal dialysis developed a peritonitis due to Pasteurella multocida after physical contact of the domestic cat with the dialysis machine. Only 25 of such cases have been reported, mostly concerning adults. We report the third case involving a child, together with a literature review.

Pasteurella multocida toxin interaction with host cells: entry and cellular effects

The mitogenic dermonecrotic toxin from Pasteurella multocida (PMT) is a 1285-residue multipartite protein that belongs to the A-B family of bacterial protein toxins. Through its G-protein-deamidating activity on the α subunits of heterotrimeric G(q)-, G(i)- and G(12/13)-proteins, PMT potently stimulates downstream mitogenic, calcium, and cytoskeletal signaling pathways. These activities lead to pleiotropic effects in different cell types, which ultimately result in cellular proliferation, while inhibiting cellular differentiation, and account for the myriad of physiological outcomes observed during infection with toxinogenic strains of P. multocida.

Cellular and molecular action of the mitogenic protein-deamidating toxin from Pasteurella multocida

The mitogenic toxin from Pasteurella multocida (PMT) is a member of the dermonecrotic toxin family, which includes toxins from Bordetella, Escherichia coli and Yersinia. Members of the dermonecrotic toxin family modulate G-protein targets in host cells through selective deamidation and/or transglutamination of a critical active site Gln residue in the G-protein target, which results in the activation of intrinsic GTPase activity. Structural and biochemical data point to the uniqueness of PMT among these toxins in its structure and action. Whereas the other dermonecrotic toxins act on small Rho GTPases, PMT acts on the α subunits of heterotrimeric G(q) -, G(i) - and G(12/13) -protein families. To date, experimental evidence supports a model in which PMT potently stimulates various mitogenic and survival pathways through the activation of G(q) and G(12/13) signaling, ultimately leading to cellular proliferation, whilst strongly inhibiting pathways involved in cellular differentiation through the activation of G(i) signaling. The resulting cellular outcomes account for the global physiological effects observed during infection with toxinogenic P. multocida, and hint at potential long-term sequelae that may result from PMT exposure.

Animal bite-associated infections: microbiology and treatment

Human and animal bites may lead to serious infection. The organisms involved tend to originate from the oral cavity of the offending biter, as well as the environment where the injury occurred. A variety of aerobic as well as anaerobic organisms have been isolated from bite wounds, with infection ranging from localized cellulitis to systemic dissemination, leading to severe disease ranging from abscess to bone and joint infection, to endocarditis and brain abscess. Immediate wound management, including recognition of the most commonly associated infectious pathogens, and judicious use of empiric antibiotics are crucial in providing the best care after a bite. Here, we discuss the common animal bite associated infections, and provide the most up to date information regarding their management.

Pasteurella multocida infection, a rare cause of mycotic abdominal aortic aneurysm

A 64-year-old man was admitted with abdominal pain 6 weeks after treatment with intravenous flucloxacillin for cellulitis of his right leg. Urgent operation was necessary for a mycotic aneurysm of the abdominal aorta due to infection with Pasteurella multocida, a microorganism residing in the oral cavity of domestic animals that very rarely causes infection of native arteries or grafts. The aorta was repaired with a rifampin-coated tube graft. Despite postoperative duodenal perforation, abdominal Candida infections, wound dehiscence, and renal insufficiency, the patient is alive 1 year postoperatively.