Thermophilic multidrug-resistant Campylobacter fetus infection with hypersplenism and histiocytic phagocytosis in a patient with acquired immunodeficiency syndrome

Phenotypic and genetic analyses of two Campylobacter fetus isolates from a patient with relapsed prosthetic valve endocarditis

Campylobacter fetus can cause intestinal and systemic disease in humans and are well established veterinary and economic pathogens. We report the complete genomic sequences of two C. fetus subsp. fetus (Cff) isolates recovered in 2017 (CITCf01) and 2018 (CITCf02) from a case of recurrent prosthetic valve endocarditis. Both were capable of growth aerobically. Their genomes were found to be highly conserved and syntenic with 99.97% average nucleotide identity (ANI) while differences in their respective sap loci defined the temporal separation of their genomes. Based on core genome phylogeny and ANI of 83 Cff genomes belonging to the previously described human-associated Cff lineage, CITCf01 and CITCf02 grouped in a clade of eleven sequence type (ST)3 Cff (including the Cff type strain NCTC 10842T). CITCf01 and CITCf02 were marked for their lack of unique genomic features when compared to isolates within the subspecies and the type strain in particular. We identified point mutations in oxidative stress response genes, among others, that may contribute to aerobiosis. We report a case of Cff causing relapsed prosthetic valve endocarditis and we highlight the sap island as a polymorphic site within the genetically stable ST3 lineage, central to pathogenicity.

Macrophage Activation Syndrome

Hemophagocytic lymphohistiocytosis (HLH), or termed macrophage activation syndrome (MAS) when associated with rheumatic disorders, is a frequently fatal complication of infections, rheumatic disorders, and hematopoietic malignancies. Clinically, HLH/MAS is a life-threatening condition that is usually diagnosed among febrile hospitalized patients (children and adults) who commonly present with unremitting fever and a shock-like multiorgan dysfunction scenario. Laboratory studies reveal pancytopenia, elevated liver enzymes, elevated markers of inflammation (ESR, CRP), hyperferritinemia, and features of coagulopathy. In about 60% of cases, excess hemophagocytosis (macrophages/histiocytes engulfing other hematopoietic cell types) is noted on biopsy specimens from the bone marrow, liver, lymph nodes, and other organs. HLH/MAS has been hypothesized to occur when a threshold level of inflammation has been achieved, and genetic and environmental risk factors are believed to contribute to the hyperinflammatory state. A broad variety of infections, from viruses to fungi to bacteria, have been identified as triggers of HLH/MAS, either in isolation or in addition to an underlying inflammatory disease state. Certain infections, particularly by members of the herpesvirus family, are the most notorious triggers of HLH/MAS. Treatment for infection-triggered MAS requires therapy for both the underlying infection and dampening of the hyperactive immune response.

Antimicrobial Resistance in Campylobacter Species: Mechanisms and Genomic Epidemiology

The Campylobacter genus is a large and diverse group of Gram-negative bacteria that are known to colonize humans and other mammals, birds, reptiles, and shellfish. While it is now recognized that several emerging Campylobacter species can be associated with human disease, two species, C. jejuni and C. coli, are responsible for the vast majority of bacterial gastroenteritis in humans worldwide. Infection with C. jejuni, in particular, has also been associated with a number of extragastrointestinal manifestations and autoimmune conditions, most notably Guillain-Barré syndrome. The antimicrobial drugs of choice for the treatment of severe Campylobacter infection include macrolides, such as erythromycin, clarithromycin, or azithromycin. Fluoroquinolones, such as ciprofloxacin, are also commonly used for empirical treatment of undiagnosed diarrheal disease. However, resistance to these and other classes of antimicrobial drugs is increasing and is a major public health problem. The US Centers for Disease Control and Prevention estimates that over 300,000 infections per year are caused by drug-resistant Campylobacter. In this chapter, we discuss the taxonomy of the Campylobacter genus, the clinical and global epidemiological aspects of Campylobacter infection, with an emphasis on C. jejuni and C. coli, and issues related to the treatment of infection and antimicrobial resistance mechanisms. We further discuss the use of next-generation sequencing for the detection and surveillance of antimicrobial resistance genes.

Secondary macrophage activation syndrome due to autoimmune, hematologic, infectious and oncologic diseases. Thirteen case series and review of the literature

OBJECTIVE

Describe the demographic characteristics and disorders of patients with diagnosis of Macrophage Activation Syndrome (MAS) in the December 2008 - January 2014 period.

METHODS

Medical records were reviewed from diagnosis of MAS and after discharge until January 2014. Patients were divided into 4 groups according to the primary disease: Autoimmune (AI), Hemato - oncologic (HO), Infectious (Inf) and Oncologic (Onc). The variables were analyzed among the 4 groups and between AI and HO.

RESULTS

Thirteen patients [7 men, with a median of 54 years (32-63)] were studied. The etiologies were: 5 AI, 5 HO, 2 Inf. and 1 Onc. disease. Hemophagocitc cells were found in the ascitic fluid of one patient. A patient with MAS secondary to IgG4-related disease was found.

CONCLUSIONS

Mortality, prognosis and disease progression may be influenced by the delay in diagnosis, treatment initiation and etiology of MAS. HO ill patients had a worse prognosis.

So close and yet so far - Molecular Microbiology of Campylobacter fetus subspecies

Campylobacter fetus comprises two subspecies, C. fetus subsp. fetus and C. fetus subsp. venerealis, which are considered emerging pathogens in humans and animals. Comparisons at the genome level have revealed modest subspecies-specific variation; nevertheless, these two subspecies show distinct host and niche preferences. C. fetus subsp. fetus is a commensal and pathogen of domesticated animals that can be transmitted to humans via contaminated food. The clinical features of human infection can be severe, especially in impaired hosts. In contrast, C. fetus subsp. venerealis is a sexually transmitted pathogen essentially restricted to cattle. Infections leading to bovine venereal campylobacteriosis cause substantial economic losses due to abortion and infertility. Recent genome sequencing of the two subspecies has advanced our understanding of C. fetus adaptations through comparative genomics and the identification of subspecies-specific gene regions predicted to be involved in pathogenesis. The most striking difference between the subspecies is the highly subspecies-specific association of a pathogenicity island in the C. fetus subsp. venerealis chromosome. The inserted region encodes a Type 4 secretion system, which contributes to virulence properties of this organism in vitro. This review describes the main differences in epidemiological, phenotypic, and molecular characteristics of the two subspecies and summarizes recent advances towards understanding the molecular mechanisms of C. fetus pathogenesis.

Fatal relapse of a purulent pleurisy caused by Campylobacter fetus subsp. fetus

Campylobacter fetus is associated with invasive disease, while other Campylobacter species, such as C. coli and C. jejuni, are a common cause of bacterial diarrhea. Bacteremia has been well described, but pleurisy remains very uncommon. We report the recurrent isolation of a C. fetus subsp. fetus strain during two episodes of pleural effusion with a fatal outcome.

Temporal prevalence of antimicrobial resistance in Campylobacter spp. from beef cattle in Alberta feedlots

Antimicrobial resistance (AMR) was temporally assessed in campylobacters isolated from beef cattle (7,738 fecal samples from 2,622 animals) in four commercial feedlots in Alberta. All calves were administered chlortetracycline and oxytetracycline in feed, and a majority of the animals (93%) were injected with long-acting oxytetracycline upon arrival at the feedlot. Fecal samples from individual animals were collected upon arrival (i.e., entry sample), 69 days (standard deviation [SD] = 3 days) after arrival (i.e., interim sample), and 189 days (SD = 33 days) after arrival (i.e., exit sample) at the feedlot. In total, 1,586 Campylobacter isolates consisting of Campylobacter coli (n = 154), Campylobacter fetus (n = 994), Campylobacter jejuni (n = 431), Campylobacter hyointestinalis (n = 4), and Campylobacter lanienae (n = 3) were recovered and characterized. The administration of antimicrobials did not decrease carriage rates of campylobacters, and minimal resistance (< or =4%) to azithromycin, ciprofloxacin, enrofloxacin, gentamicin, and meropenem was observed. In contrast, substantive increases in the prevalence of isolates resistant to tetracycline and doxycycline (56 to 89%) for C. coli, C. fetus, and C. jejuni, as well as in the number of animals (7 to 42%) from which resistant isolates were recovered, were observed during the feedlot period. Increased resistance to erythromycin (total isolates and carriages rates) was also observed in isolates of C. coli over the three isolation times. The majority of C. fetus isolates recovered were resistant to nalidixic acid, but this was independent of when they were isolated. A relatively limited number of multidrug-resistant isolates were recovered and consisted primarily of C. coli resistant to tetracyclines and erythromycin (10% of isolates). Over the course of the feedlot period, considerable increases in antimicrobial resistance were observed in C. coli, C. fetus, and C. jejuni, but with the exception of erythromycin resistance in C. coli, the administration of antimicrobial agents to beef cattle was found to have a minimal impact on resistance to macrolides and fluoroquinolones, the two classes of antimicrobials used to treat campylobacteriosis in humans. However, the widespread use of antimicrobial agents in beef production and the possible horizontal transfer of mobile genetic elements with antimicrobial resistance determinants among Campylobacter and other bacterial taxa emphasize the need to monitor AMR development in bacteria from beef cattle.

Gastrointestinal infections in the immunocompromised host

Immunocompromised patients, including patients with AIDS, solid organ and bone marrow transplant recipients, patients with leukemia and lymphoma, patients with inherited immune deficiencies, and patients on immunosuppressive therapy for a variety of disorders, are at risk for infections-particularly opportunistic infections, which, by definition, do not infect the healthy host. All systems of the body, including the gastrointestinal tract, are susceptible. The esophagus, stomach, small intestine, and large intestine are sites of infection for viruses, bacteria, fungi, and protozoa. Symptoms can range in severity from fevers of unknown etiology to life-threatening hemorrhage and perforation. This review summarizes recent case reports, clinical studies, and reviews pertaining to pathogens that uniquely cause disease, more frequently cause disease, or cause more severe disease in the immunocompromised host than in the immunocompetent host.