Recurrent Fever due to Helicobacter cinaedi Infection during R-CHOP Chemotherapy in Diffuse Large B-Cell Lymphoma: Case Report and Literature Review

Fever due to Helicobacter cinaedi bacteremia under chemotherapy has not been widely recognized among clinicians. We experienced a 72-year-old man with diffuse large B-cell lymphoma, who was complicated with H. cinaedi bacteremia-induced fever under R-CHOP chemotherapy. We summarized 6 cases including ours, suggesting that fever without neutropenia developing around day 6 from starting chemotherapy is a possible symptom caused by H. cinaedi bacteremia. We should discriminate fever due to H. cinaedi bacteremia if fever emerged before myelosuppression in the course of chemotherapy.

Getting to the Heart of the Matter: A 20-Year-Old Man With Fever, Rash, and Chest Pain

Infection with Helicobacter cinaedi can encompass a wide spectrum of clinical manifestations, including fever, rash, endocarditis, osteomyelitis, and meningitis. The present case demonstrates the ability of H cinaedi to masquerade as acute rheumatic fever and represents the first reported case of cardiac tamponade caused by H cinaedi.

Mutations in Genes Encoding Penicillin-Binding Proteins and Efflux Pumps Play a Role in β-Lactam Resistance in Helicobacter cinaedi

β-Lactams are often used to treat Helicobacter cinaedi infections; however, the mechanism underlying β-lactam resistance is unknown. In this study, we investigated β-lactam resistance in an H. cinaedi strain, MRY12-0051 (MICs of amoxicillin [AMX] and ceftriaxone [CRO], 32 and 128 μg/ml; obtained from human feces). Based on a comparative whole-genome analysis of MRY12-0051 and the CRO-susceptible H. cinaedi strain MRY08-1234 (MICs of AMX and CRO, 1 and 4 μg/ml; obtained from human blood), we identified five mutations in genes encoding penicillin-binding proteins (PBPs), including two in pbpA, one in pbp2, and two in ftsI Transformation and penicillin binding assays indicated that CRO resistance was mainly associated with mutations in pbpA; mutations in ftsI also led to increased resistance to AMX. Knocking out cmeB and cmeD, which encode resistance-nodulation-division-type efflux pump components, in H. cinaedi type strain CCUG18818 (AMX MIC, 4 to 8 μg/ml) resulted in 8- and 64-fold decreases, respectively, in the AMX MIC. Hence, MICs of AMX in H. cinaedi become similar to those of Helicobacter pylori isolates in the absence of cmeD In conclusion, the difference in susceptibility to β-lactams between H. pylori and H. cinaedi is explained by differences in efflux pump components. Mutations in pbpA are the primary determinant of high resistance to β-lactams in H. cinaedi.

Other Helicobacters and gastric microbiota

This article aimed to review the literature from 2015 dealing with gastric and enterohepatic non-Helicobacter pylori Helicobacter species (NHPH). A summary of the gastric microbiota interactions with H. pylori is also presented. An extensive number of studies were published during the last year and have led to a better understanding of the pathogenesis of infections with NHPH. These infections are increasingly reported in human patients, including infections with H. cinaedi, mainly characterized by severe bacteremia. Whole-genome sequencing appears to be the most reliable technique for identification of NHPH at species level. Presence of NHPH in laboratory animals may influence the outcome of experiments, making screening and eradication desirable. Vaccination based on UreB proteins or bacterial lysate with CCR4 antagonists as well as oral glutathione supplementation may be promising strategies to dampen the pathogenic effects associated with gastric NHPH infections. Several virulent factors such as outer membrane proteins, phospholipase C-gamma 2, Bak protein, and nickel-binding proteins are associated with colonization of the gastric mucosae and development of gastritis. The development of high-throughput sequencing has led to new insights in the gastric microbiota composition and its interaction with H. pylori. Alterations in the gastric microbiota caused by the pH-increasing effect of a H. pylori infection may increase the risk for gastric cancer.