Case of acute pancreatitis associated with Campylobacter enteritis

Renal Abscess and Recurrent Bacteremia Caused by Campylobacter Infection in an Adult With Common Variable Immunodeficiency

Campylobacter bacteremia and extraintestinal manifestations are extremely rare, occurring more frequently in immunocompromised patients. We report a rare clinical case of a 46-year-old female with common variable immunodeficiency (CVID) presenting with a previously undescribed extraintestinal complication - renal abscess - and recurrent bacteremia caused by Campylobacter, which was a therapeutic challenge and required the use of secondary prophylactic antibiotic treatment to prevent recurrence.

Infectious causes of acute pancreatitis: A systematic review

BACKGROUND

Infectious etiologies of acute pancreatitis (AP) are rare and include viruses, bacteria, mycobacteria, parasites, and fungi. We aimed to conduct a comprehensive review on infectious etiologies of AP analyzing the frequency, clinical features, and outcomes of individuals presenting with this condition.

METHODS

Eligible articles reporting on AP attributed to infectious etiologies were included. A comprehensive literature search of PubMed from time of inception and until September 6,2019 was performed using all relevant MeSH (medical subject heading) keywords. Articles were assessed for eligibility and independently reviewed by two reviewers for clinical features of AP, local complications, and mortality. Methodological quality of included studies was evaluated using the Murad tool.

RESULTS

A total of 212 articles were included, of which 168 (79.2%) were at high risk of bias. 320 cases of AP were identified. Viruses were the leading etiology of infection attributed AP (65.3%) followed by helminths (19.1%), and bacteria (12.5%). Protozoa, mycobacteria, and fungi accounted for the remaining 3.1% of cases. Mean age was 40.5 ± 18.4 years and M:F ratio was 1.94:1. Mortality occurred in 50 patients. Mortality rate was higher in the virus attributed AP patients than AP from other infectious etiologies (21.8% vs. 7.0%, p < 0.0005).

INTERPRETATION

Literature quality on infection attributed AP is limited. Virus attributed AP appears to carry a higher mortality than other etiologies of infection attributed AP.

The PAS Domain-Containing Protein HeuR Regulates Heme Uptake in Campylobacter jejuni

Campylobacter jejuni is a leading cause of bacterially derived gastroenteritis. A previous mutant screen demonstrated that the heme uptake system (Chu) is required for full colonization of the chicken gastrointestinal tract. Subsequent work identified a PAS domain-containing regulator, termed HeuR, as being required for chicken colonization. Here we confirm that both the heme uptake system and HeuR are required for full chicken gastrointestinal tract colonization, with the heuR mutant being particularly affected during competition with wild-type C. jejuni Transcriptomic analysis identified the chu genes-and those encoding other iron uptake systems-as regulatory targets of HeuR. Purified HeuR bound the chuZA promoter region in electrophoretic mobility shift assays. Consistent with a role for HeuR in chu expression, heuR mutants were unable to efficiently use heme as a source of iron under iron-limiting conditions, and mutants exhibited decreased levels of cell-associated iron by mass spectrometry. Finally, we demonstrate that an heuR mutant of C. jejuni is resistant to hydrogen peroxide and that this resistance correlates to elevated levels of catalase activity. These results indicate that HeuR directly and positively regulates iron acquisition from heme and negatively impacts catalase activity by an as yet unidentified mechanism in C. jejuni IMPORTANCE: Annually, Campylobacter jejuni causes millions of gastrointestinal infections in the United States, due primarily to its ability to reside within the gastrointestinal tracts of poultry, where it can be released during processing and contaminate meat. In the developing world, humans are often infected by consuming contaminated water or by direct contact with livestock. Following consumption of contaminated food or water, humans develop disease that is characterized by mild to severe diarrhea. There is a need to understand both colonization of chickens, to make food safer, and colonization of humans, to better understand disease. Here we demonstrate that to efficiently colonize a host, C. jejuni requires iron from heme, which is regulated by the protein HeuR. Understanding how HeuR functions, we can develop ways to inhibit its function and reduce iron acquisition during colonization, potentially reducing C. jejuni in the avian host, which would make food safer, or limiting human colonization.