Comparison of two methods used for monitoring low-copy cytomegalovirus infection in a patient with chronic myeloid leukemia after unrelated umbilical cord blood transplantation

Next-generation sequencing in the diagnosis of viral encephalitis: sensitivity and clinical limitations

Identification of pathogens causing viral encephalitis remains challenging, and in over 50% of cases the etiologic factor remains undetermined. Next-generation sequencing (NGS) based metagenomics has been successfully used to detect novel and rare infections, but its value for routine diagnosis of encephalitis remains unclear. The aim of the present study was to determine the sensitivity of shotgun metagenomic sequencing protocols, which include preamplification, and testing it against cerebrospinal fluid (CSF) samples from encephalitis patients. For sensitivity testing HIV and HBV positive sera were serially diluted in CSF from an uninfected patient. NGS repeatedly detected HIV and HBV sequences present at concentrations from 10⁵ to 10² and from 10⁵ to 10 viral copies/reaction, respectively. However, when the same protocols were applied to RT-PCR/PCR positive CSF samples from 6 patients with enteroviral encephalitis (median viral load 47 copies/ml) and 15 patients with HSV, CMV or VZV encephalitis (median viral load 148 copies/ml), only 7 (28.6%) were identified as positive. In conclusions, while NGS has the advantage of being able to identify a wide range of potential pathogens it seems to be less sensitive compared to the standard amplification-based assays in the diagnosis of encephalitis, where low viral loads are common.

Prevalence of cytomegalovirus DNA in cord blood and voided urine obtained from pregnant women at the end of pregnancy

OBJECTIVE

This study was undertaken to determine the prevalence of congenital cytomegalovirus (CMV) infection in pregnant women at the end of pregnancy in Kuwait using cord blood and maternal urine.

SUBJECTS AND METHODS

Urine samples were collected prior to childbirth, and cord blood was collected immediately after delivery from 983 women. Anti-CMV IgG and IgM antibodies were determined using ELISA; CMV DNA was detected using nested PCR, and viral load was calculated using real-time PCR. CMV concentration in samples was categorized as low when the viral load ≤10(3) copies/µl, intermediate when the viral load = 10(3)-10(4) copies/µl, and high when the viral load >10(4) copies/µl. The cord blood serology outcome was compared to cord blood PCR, cord blood viral load, maternal urine PCR and viral load analyses.

RESULTS

Serology showed that of the 983 cord blood samples, 89 (9%) were positive for anti-CMV IgM antibodies; PCR test showed 44 (4.5%) contained CMV DNA, and there was a high viral load in all. Maternal urine PCR showed that 9 (10.11%) women had CMV DNA, and there was a high viral load in 7 (78%). The kappa test for measures of agreement showed a reasonable agreement (0.45) between cord blood PCR and urine PCR.

CONCLUSION

This study showed that CMV infection in the cord blood sera of pregnant women is common in Kuwait and highlights the need for more clinically based studies to follow up newborns with congenital CMV infection.