The transplant cohort of the German center for infection research (DZIF Tx-Cohort): study design and baseline characteristics

Occurrence of respiratory viruses among outpatients with diarrhea in Beijing, China, 2019-2020

Objectives

To investigate respiratory virus infections in diarrhea cases and identify the risk of respiratory virus transmission through feces.

Methods

Fecal specimens were collected from diarrhea cases in enteric disease clinics in Beijing, China, from 2019 to 2020. Cases that tested negative for norovirus, rotavirus, sapovirus, astrovirus, and enteric adenovirus were included in the study. Real-time RT-PCR was used to detect 16 groups of respiratory viruses, and the major viruses were genotyped. Viruses isolation and digestion of clinical specimens and nucleic acid by artificial gastric acid or artificial bile/pancreatic juice were used to evaluate the risk of respiratory virus transmission through feces.

Results

A total of 558 specimens were collected and 47 (8.42%) specimens were detected positive, 40 (13.33%, 40/300) in 2019, and 7 (2.71%, 7/258) in 2020, including 20 (3.58%) for human rhinovirus (HRV), 13 (2.32%) for Bocavirus (BoV), 6 (1.08%) for parainfluenza virus I (PIV), 4 (0.72%) for coronavirus (CoV) OC43, 3 (0.54%) for respiratory syncytial virus (RSV) A, and 1 (0.18%) for both BoV and CoV OC43. Syndrome coronavirus 2 (SARS-CoV-2) and other viruses were not detected in this study. Eight genotypes were identified in the 13 HRV specimens. BoVs 1 and 2 were identified in nine BoV specimens. HRV infectious virions were successfully isolated from 2 clinical specimens and clinical specimens of HRV, RSV, PIV, and CoV could not be detected after 4 h of digestion and their nucleic acid could not be detected after 2 h of digestion by artificial gastric acid or artificial bile/pancreatic juice.

Conclusion

There may be a risk of respiratory virus transmission from diarrhea cases, and interventions against SARS-COV-2 epidemics are also effective for other respiratory viruses.

Incidences of infectious events in a renal transplant cohort of the German Center of Infectious Diseases (DZIF)

Background

Infectious complications are a major cause of morbidity and mortality after kidney transplantation.

Methods

In this transplant cohort study at the German Center of Infectious Diseases (DZIF), we evaluated all infections occurring during the first year after renal transplantation. We assessed microbial etiology, incidence rates, and temporal occurrence of these infections.

Results

Of 804 renal transplant recipients (65.2% male, 51 ± 14 years), 439 (54.6%) had 972 infections within the first year after transplantation. Almost half of these infections (47.8%) occurred within the first three months. Bacteria were responsible for 66.4% (645/972) of all infections, followed by viral (28.9%[281/972]) and fungal (4.7%[46/972]) pathogens. The urinary tract was the most common site of infection (42.4%). Enterococcus was most frequently isolated bacteria (20.9%), followed by E.coli (17.6%) and Klebsiella (12.5%). E.coli was the leading pathogen in recipients <50 years of age, whereas Enterococcus predominated in older recipients. Resistant bacteria were responsible for at least one infection in 9.5% (76/804) of all recipients. Viral infections occurred in 201 recipients (25.0%). Of these, herpes viruses predominated (140/281[49.8%]) and cytomegalovirus had the highest incidence rate (12.3%). In the 46 fungal infections, Candida albicans (40.8%) was most commonly isolated. Other fungal opportunistic pathogens, including Aspergillus fumigatus and Pneumocystis, were rare.

Conclusions

Renal allograft recipients in Germany experience a high burden of infectious complications in the first year after transplantation. Bacteria were the predominating pathogen, followed by opportunistic infections such as cytomegalovirus. Microbial etiology varied between age groups and resistant bacteria were identified in 10% of recipients.

Human cytomegalovirus multiple-strain infections and viral population diversity in haematopoietic stem cell transplant recipients analysed by high-throughput sequencing

Human cytomegalovirus (HCMV) is an important opportunistic pathogen in allogeneic haematopoietic stem cell transplant (HSCT) recipients. High-throughput sequencing of target-enriched libraries was performed to characterise the diversity of HCMV strains present in this high-risk group. Forty-four HCMV-DNA-positive plasma specimens (median viral input load 321 IU per library) collected at defined time points from 23 HSCT recipients within 80 days of transplantation were sequenced. The genotype distribution for 12 hypervariable HCMV genes and the number of HCMV strains present (i.e. single- vs. multiple-strain infection) were determined for 29 samples from 16 recipients. Multiple-strain infection was observed in seven of these 16 recipients, and five of these seven recipients had the donor (D)/recipient (R) HCMV-serostatus combination D + R + . A very broad range of genotypes was detected, with an intrahost composition that was generally stable over time. Multiple-strain infection was not associated with particular virological or clinical features, such as altered levels or duration of antigenaemia, development of acute graft-versus-host disease or increased mortality. In conclusion, despite relatively low viral plasma loads, a high frequency of multiple-strain HCMV infection and a high strain complexity were demonstrated in systematically collected clinical samples from this cohort early after HSCT. However, robust evaluation of the pathogenic role of intrahost viral diversity and multiple-strain infection will require studies enrolling larger numbers of recipients.