Point-of-Care Testing for Hepatitis Viruses: A Growing Need

Viral hepatitis, caused by hepatitis A virus (HAV), hepatitis B virus (HBV), hepatitis C virus (HCV), hepatitis D virus (HDV), or hepatitis E virus (HEV), is a major global public health problem. These viruses cause millions of infections each year, and chronic infections with HBV, HCV, or HDV can lead to severe liver complications; however, they are underdiagnosed. Achieving the World Health Organization's viral hepatitis elimination goals by 2030 will require access to simpler, faster, and less expensive diagnostics. The development and implementation of point-of-care (POC) testing methods that can be performed outside of a laboratory for the diagnosis of viral hepatitis infections is a promising approach to facilitate and expedite WHO's elimination targets. While a few markers of viral hepatitis are already available in POC formats, tests for additional markers or using novel technologies need to be developed and validated for clinical use. Potential methods and uses for the POC testing of antibodies, antigens, and nucleic acids that relate to the diagnosis, monitoring, or surveillance of viral hepatitis infections are discussed here. Unmet needs and areas where additional research is needed are also described.

Hepatitis C virus transmission cluster among injection drug users in Pakistan

Hepatitis C virus (HCV) infections are public health problem across the globe, particularly in developing countries. Pakistan has the second highest prevalence of HCV infection worldwide. Limited data exist from Pakistan about persons who inject drugs (PWID) and are at significant risk of exposure to HCV infection and transmission. Serum specimens (n = 110) collected from PWID residing in four provinces were tested for molecular markers of HCV infection. Next generation sequencing (NGS) of the hypervariable region (HVR1) of HCV and Global Hepatitis Outbreak and Surveillance Technology (GHOST) were used to determine HCV genotype, genetic heterogeneity, and construct transmission networks. Among tested specimens, 47.3% were found anti-HCV positive and 34.6% were HCV RNA-positive and belonged to four genotypes, with 3a most prevalent followed by 1a, 1b and 4a. Variants sampled from five cases formed phylogenetic cluster and a transmission network. One case harbored infection with two different genotypes. High prevalence of infections and presence of various genotypes indicate frequent introduction and transmission of HCV among PWID in Pakistan. Identification of a transmission cluster across three provinces, involving 20% of all cases, suggests the existence of a countrywide transmission network among PWIDs. Understanding the structure of this network should assist in devising effective public health strategies to eliminate HCV infection in Pakistan.

Precore and Basal Core Promoter Hepatitis B Virus (HBV) Variants Are Present From a Young Age and Differ Across HBV Genotypes

BACKGROUND AND AIMS

Hepatitis B virus (HBV) precore (PC) and dual basal core promoter (BCP) mutations halt and down-regulate hepatitis B e antigen (HBeAg) production respectively. PC mutation is rarely associated with HBV genotype A. We sought to examine the association of these variants with HBV genotypes, age, and HBeAg status in a racially diverse population in North America. Prospective study included 1,036 (808 adults, 228 children) participants in the Hepatitis B Research Network. PC and BCP variants were determined by Sanger sequencing, and dominant HBV species (>50%) were reported.

APPROACH AND RESULTS

Median age was 36.3 years (range, 2-80), 44.6% HBeAg(+), 74.2% Asians, 13.3% black, and 9.7% white. The dominant PC variant was present in 29.4% participants, including 20 with subgenotype A1 or A2. Seventeen of 20 participants with genotype A and PC had a compensatory C1858T mutation. In the HBeAg(+) cohort, the prevalence of PC and/or BCP variants increased from 14.4% in the first two decades to 51% after 40 years of age. Among those aged 2-18, 52% and 83% with dominant PC and BCP variants were HBeAg(+) compared to 3.8% and 29% in the >40 years age group. HBeAg clearance rates were significantly higher for those with dominant PC or BCP variants: 24.4 and 15.0 per 100 person-years compared to 6.0 in wild-type HBV (P < 0.0001).

CONCLUSIONS

PC variants can be present in HBV genotype A and are usually associated with C1858T, which preserves the pregenome encapsidation sequence. Selection of PC and BCP variants occurred at a young age, with increasing prevalence across age groups. HBeAg(+) participants with dominant PC and BCP variants progressed to the HBeAg(-) phase of chronic HBV infection significantly faster. This finding has potential clinical and therapeutic implications.

A Phylogenetic Analysis of Hepatitis C Virus Transmission, Relapse, and Reinfection Among People Who Inject Drugs Receiving Opioid Agonist Therapy

BACKGROUND

Understanding hepatitis C virus (HCV) transmission among people who inject drugs (PWID) is essential for HCV elimination. We aimed to differentiate reinfections from treatment failures and to identify transmission linkages and associated factors in a cohort of PWID receiving opioid agonist therapy (OAT).

METHODS

We analyzed baseline and follow-up specimens from 150 PWID from 3 OAT clinics in the Bronx, New York. Next-generation sequencing data from the hypervariable region 1 of HCV were analyzed using Global Hepatitis Outbreak and Surveillance Technology.

RESULTS

There were 3 transmission linkages between study participants. Sustained virologic response (SVR) was not achieved in 9 participants: 7 had follow-up specimens with similar sequences to baseline, and 2 died. In 4 additional participants, SVR was achieved but the participants were viremic at later follow-up: 2 were reinfected with different strains, 1 had a late treatment failure, and 1 was transiently viremic 17 months after treatment. All transmission linkages were from the same OAT clinic and involved spousal or common-law partnerships.

CONCLUSION

This study highlights the use of next-generation sequencing as an important tool for identifying viral transmission and to help distinguish relapse and reinfection among PWID. Results reinforce the need for harm reduction interventions among couples and those who report ongoing risk factors after SVR.

Integrated HIV surveillance finds recent adult hepatitis B virus (HBV) transmission and intermediate HBV prevalence among military in uncharacterized Caribbean country

Background

Guyana expanded its HIV response in 2005 but the epidemiology of hepatitis B virus (HBV) and hepatitis C virus (HCV) infections has not been characterized.

Methods

The 2011 Seroprevalence and Behavioral Epidemiology Risk Survey for HIV and STIs collected biologic specimens with demographic and behavioral data from a representative sample of Guyana military personnel. Diagnostics included commercial serum: HIV antibody; total antibody to hepatitis B core (anti-HBc); IgM anti-HBc; hepatitis B surface antigen (HBsAg); anti-HBs; antibody to HCV with confirmatory testing; and HBV DNA sequencing with S gene fragment phylogenetic analysis. Chi-square, p-values and prevalence ratios determined statistical significance.

Results

Among 480 participants providing serologic specimens, 176 (36.7%) tested anti-HBc-positive. Overall, 19 (4.0%) participants tested HBsAg-positive; 17 (89.5%) of the HBsAg-positive participants also had detectable anti-HBc, including 1 (5.3%) IgM anti-HBc-positive male. Four (6.8%) females with available HBV testing were HBsAg-positive, all aged 23–29 years. Sixteen (16, 84.2%) HBsAg-positive participants had sufficient specimen for DNA testing. All 16 had detectable HBV DNA, 4 with viral load >2x10⁴IU/ml. Sequencing found: 12 genotype (gt) A1 with 99.9% genetic identity between 1 IgM anti-HBc-positive and 1 anti-HBc-negative; 2 gtD1; and 2 with insufficient specimen. No statistically significant associations between risk factors and HBV infection were identified.

Conclusions

Integrated HIV surveillance identified likely recent adult HBV transmission, current HBV infection among females of reproductive age, moderate HBV infection prevalence (all gtA1 and D1), no HCV infections and low HIV frequency among Guyana military personnel. Integrated HIV surveillance helped characterize HBV and HCV epidemiology, including probable recent transmission, prompting targeted responses to control ongoing HBV transmission and examination of hepatitis B vaccine policies.

HCV transmission in high-risk communities in Bulgaria

Background

The rate of HIV infection in Bulgaria is low. However, the rate of HCV-HIV-coinfection and HCV infection is high, especially among high-risk communities. The molecular epidemiology of those infections has not been studied before.

Methods

Consensus Sanger sequences of HVR1 and NS5B from 125 cases of HIV/HCV coinfections, collected during 2010–2014 in 15 different Bulgarian cities, were used for preliminary phylogenetic evaluation. Next-generation sequencing (NGS) data of the hypervariable region 1 (HVR1) analyzed via the Global Hepatitis Outbreak and Surveillance Technology (GHOST) were used to evaluate genetic heterogeneity and possible transmission linkages. Links between pairs that were below and above the established genetic distance threshold, indicative of transmission, were further examined by generating k-step networks.

Results

Preliminary genetic analyses showed predominance of HCV genotype 1a (54%), followed by 1b (20.8%), 2a (1.4%), 3a (22.3%) and 4a (1.4%), indicating ongoing transmission of many HCV strains of different genotypes. NGS of HVR1 from 72 cases showed significant genetic heterogeneity of intra-host HCV populations, with 5 cases being infected with 2 different genotypes or subtypes and 6 cases being infected with 2 strains of same subtype. GHOST revealed 8 transmission clusters involving 30 cases (41.7%), indicating a high rate of transmission.

Four transmission clusters were found in Sofia, three in Plovdiv, and one in Peshtera. The main risk factor for the clusters was injection drug use. Close genetic proximity among HCV strains from the 3 Sofia clusters, and between HCV strains from Peshtera and one of the two Plovdiv clusters confirms a long and extensive transmission history of these strains in Bulgaria.

Conclusions

Identification of several HCV genotypes and many HCV strains suggests a frequent introduction of HCV to the studied high-risk communities. GHOST detected a broad transmission network, which sustains circulation of several HCV strains since their early introduction in the 3 cities. This is the first report on the molecular epidemiology of HIV/HCV coinfections in Bulgaria.

Reactivation of a Vaccine Escape Hepatitis B Virus Mutant in a Cambodian Patient During Anti-Hepatitis C Virus Therapy

A 76-year-old Cambodian man co-infected with hepatitis B virus (HBV) and hepatitis C virus (HCV) 6c-1 presented for care. HBV DNA was intermittently detectable despite anti-HBs levels being above the protective threshold. During treatment for HCV, HBV DNA levels increased. Sequencing revealed multiple mutations including vaccine escape mutation and mutations predicted to enhance fitness. This case represents exacerbation of an HBV vaccine escape mutant during a direct-acting antiviral therapy.

GHOST: global hepatitis outbreak and surveillance technology

Background

Hepatitis C is a major public health problem in the United States and worldwide. Outbreaks of hepatitis C virus (HCV) infections associated with unsafe injection practices, drug diversion, and other exposures to blood are difficult to detect and investigate. Effective HCV outbreak investigation requires comprehensive surveillance and robust case investigation. We previously developed and validated a methodology for the rapid and cost-effective identification of HCV transmission clusters. Global Hepatitis Outbreak and Surveillance Technology (GHOST) is a cloud-based system enabling users, regardless of computational expertise, to analyze and visualize transmission clusters in an independent, accurate and reproducible way.

Results

We present and explore performance of several GHOST implemented algorithms using next-generation sequencing data experimentally obtained from hypervariable region 1 of genetically related and unrelated HCV strains. GHOST processes data from an entire MiSeq run in approximately 3 h. A panel of seven specimens was used for preparation of six repeats of MiSeq libraries. Testing sequence data from these libraries by GHOST showed a consistent transmission linkage detection, testifying to high reproducibility of the system. Lack of linkage among genetically unrelated HCV strains and constant detection of genetic linkage between HCV strains from known transmission pairs and from follow-up specimens at different levels of MiSeq-read sampling indicate high specificity and sensitivity of GHOST in accurate detection of HCV transmission.

Conclusions

GHOST enables automatic extraction of timely and relevant public health information suitable for guiding effective intervention measures. It is designed as a virtual diagnostic system intended for use in molecular surveillance and outbreak investigations rather than in research. The system produces accurate and reproducible information on HCV transmission clusters for all users, irrespective of their level of bioinformatics expertise. Improvement in molecular detection capacity will contribute to increasing the rate of transmission detection, thus providing opportunity for rapid, accurate and effective response to outbreaks of hepatitis C. Although GHOST was originally developed for hepatitis C surveillance, its modular structure is readily applicable to other infectious diseases. Worldwide availability of GHOST for the detection of HCV transmissions will foster deeper involvement of public health researchers and practitioners in hepatitis C outbreak investigation.

Prevalence of hepatitis B antiviral drug resistance variants in North American patients with chronic hepatitis B not receiving antiviral treatment

Antiviral drug resistance hepatitis B virus (HBV) variants (HBV-DR) occur spontaneously in chronic hepatitis B (CHB) patients and after exposure to nucleos(t)ide analogues (NUCs). We determined the prevalence of HBV-DR variants among participants of the Hepatitis B Research Network (HBRN) Cohort Study conducted at 21 sites in the United States (US) and Canada. Samples obtained from 1342 CHB participants aged ≥18 years, and who were currently not receiving NUCs, were tested for HBV-DR variants by Sanger sequencing. In addition, next generation sequencing (NGS) was used to characterize HBV-DR variants from 66 participants with and 66 participants with no prior NUC exposure matched for HBV genotype and HBV DNA level. Half the participants were men, 75% Asian, 26% HBeAg positive. Primary HBV-DR variants were detected by Sanger sequencing in 16 (1.2%) participants: 2/142 (1.4%) with and 14/1200 (1.2%) without prior NUC exposure; only 1 of these 16 had a secondary variant. In total, 23 (1.7%) participants had secondary variants, including 1 with prior NUC experience. In the subset of 132 participants, NGS detected HBV-DR variants in a higher proportion of participants: primary variants in 18 (13.6%) (8 [12.1%] with, and 10 [15.2%] without prior NUC therapy) and secondary variants in 10 (7.6%) participants. Based on Sanger sequencing, prevalence of primary HBV-DR variants is low (1.2%) among adults with CHB in US/Canada. The similar low prevalence of HBV-DR variants in participants with and without NUC treatment suggests transmission of these variants is uncommon.

Identification and comparative analysis of hepatitis B virus genotype D/E recombinants in Africa

Globally, there are approximately 240 million people chronically infected with hepatitis B virus (HBV)-a major cause of hepatocellular carcinoma. Ten different HBV genotypes (A-J) have been identified with distinct geographic distributions. Novel variants generated by recombination between different HBV genotypes have been documented worldwide and represent an important element of genetic variability with possible clinical implications. Here, the complete genome sequence of an HBV genotype D/E recombinant from Ghana is reported. The full-length sequence was obtained using rolling circle amplification followed by PCR and sequenced using next-generation sequencing (NGS). A consensus sequence was extracted from the NGS data and underwent phylogenetic analysis to determine genotype, as well as the recombination pattern. Subsequently, the sequence was compared to recombinants described previously in Africa. Based on MCMC phylogenetic analysis, SimPlot recombination analyses, and intragroup genetic distance, the isolate 007N full-length genome is unique compared to other reported D/E recombinants in Africa.

Modeling the functional state of the reverse transcriptase of hepatitis B virus and its application to probing drug-protein interaction

BACKGROUND

Herein, the predicted atomic structures of five representative sequence variants of the reverse transcriptase protein (RT) of hepatitis B virus (HBV), sampled from patients with rapid or slow response to tenofovir disoproxil fumarate (TDF) treatment, have been examined to identify structural variations between them in order to assess structural and functional properties of HBV-RT variants associated with the differential responses to TDF treatment.

RESULTS

We utilized a hybrid computational approach to model the atomistic structures of HBV-RT/DNA-RNA/dATP and HBV-RT/DNA-RNA/TFV-DP (tenofovir diphosphate) complexes with the native hybrid DNA-RNA substrate in place. Multi-nanosecond molecular dynamics (MD) simulations of HBV-RT/DNA-RNA/dATP complexes revealed strong coupling of the natural nucleotide substrate, dATP, to the active site of the RT, and the differential involvement of the two putative magnesium cations (Mg(2+)) at the active site, whereby one Mg(2+) directly bridges the interaction between dATP and HBV-RT and the other serves as a coordinator to maintain an optimal configuration of the active site. Solvated interaction energy (SIE) calculated in MD simulations of HBV-RT/DNA-RNA/TFV-DP complexes indicate no differential binding affinity between TFV-DP and HBV-RT variants identified in patients with slow or rapid response to TDF treatment.

CONCLUSION

The predicted atomic structures accurately represent functional states of HBV-RT. The equivalent interaction between TFV-DP and each examined HBV-RT variants suggests that binding affinity of TFV-DP to HBV-RT is not associated with delayed viral clearance.

Children with Chronic Hepatitis B in the United States and Canada

OBJECTIVES

To test the hypothesis that children with chronic hepatitis B living in the US and Canada would have international origins and characteristic hepatitis B virus (HBV) genotypes and laboratory profiles.

STUDY DESIGN

Clinical characteristics of children enrolled in the Hepatitis B Research Network were collected from 7 US and Canadian centers.

RESULTS

Children (n = 343) with an age range of 1.0-17.8 years were enrolled; 78% of the children were Asian, 55% were adopted, and 97% had international origins with either the child or a parent born in 1 of 31 countries. The majority had HBV genotype B (43%) or C (32%), and the remainder had genotype A (5%), D (16%), E (4%), or multiple (<1%). Children with genotype B or C were more likely to be Asian (98% and 96%), more consistently hepatitis B envelope antigen positive (95% and 82%), had higher median HBV DNA levels (8.2 and 8.3 log10 IU/mL), and less frequently had elevated alanine aminotransferase values (43% and 57%) compared with children with other genotypes. The percentage of hepatitis B envelope antigen positivity and of those with HBV DNA ≥6 log₁₀ IU/mL declined with age.

CONCLUSIONS

The majority of children in the Hepatitis B Research Network have HBV genotypes that reflect their international origins. Clinical and laboratory data differ substantially by patient age and HBV genotype. Use of these data can help drive the development of optimal strategies to manage and treat children with chronic hepatitis B.

Accurate Genetic Detection of Hepatitis C Virus Transmissions in Outbreak Settings

Hepatitis C is a major public health problem in the United States and worldwide. Outbreaks of hepatitis C virus (HCV) infections are associated with unsafe injection practices, drug diversion, and other exposures to blood and are difficult to detect and investigate. Here, we developed and validated a simple approach for molecular detection of HCV transmissions in outbreak settings. We obtained sequences from the HCV hypervariable region 1 (HVR1), using end-point limiting-dilution (EPLD) technique, from 127 cases involved in 32 epidemiologically defined HCV outbreaks and 193 individuals with unrelated HCV strains. We compared several types of genetic distances and calculated a threshold, using minimal Hamming distances, that identifies transmission clusters in all tested outbreaks with 100% accuracy. The approach was also validated on sequences obtained using next-generation sequencing from HCV strains recovered from 239 individuals, and findings showed the same accuracy as that for EPLD. On average, the nucleotide diversity of the intrahost population was 6.2 times greater in the source case than in any incident case, allowing the correct detection of transmission direction in 8 outbreaks for which source cases were known. A simple and accurate distance-based approach developed here for detecting HCV transmissions streamlines molecular investigation of outbreaks, thus improving the public health capacity for rapid and effective control of hepatitis C.

Cryptic Hepatitis B and E in Patients With Acute Hepatitis of Unknown Etiology

BACKGROUND

Up to 30% of acute viral hepatitis has no known etiology. To determine the disease etiology in patients with acute hepatitis of unknown etiology (HUE), serum specimens were obtained from 38 patients residing in the United Kingdom and Vietnam and from 26 healthy US blood donors. All specimens tested negative for known viral infections causing hepatitis, using commercially available serological and nucleic acid assays.

METHODS

Specimens were processed by sequence-independent complementary DNA amplification and next-generation sequencing (NGS). Sufficient material for individual NGS libraries was obtained from 12 HUE cases and 26 blood donors; the remaining HUE cases were sequenced as a pool. Read mapping was done by targeted and de novo assembly.

RESULTS

Sequences from hepatitis B virus (HBV) were detected in 7 individuals with HUE (58.3%) and the pooled library, and hepatitis E virus (HEV) was detected in 2 individuals with HUE (16.7%) and the pooled library. Both HEV-positive cases were coinfected with HBV. HBV sequences belonged to genotypes A, D, or G, and HEV sequences belonged to genotype 3. No known hepatotropic viruses were detected in the tested normal human sera.

CONCLUSIONS

NGS-based detection of HBV and HEV infections is more sensitive than using commercially available assays. HBV and HEV may be cryptically associated with HUE.

Hepatitis B virus and hepatitis C virus infections in United States-bound refugees from Asia and Africa

The aim of this study was to determine the prevalence of active hepatitis B and C virus infections among refugees from various countries in Africa and Asia. Pre-admission serum samples collected during 2002-2007 from refugees originating from Bhutan (N = 755), Myanmar (N = 1076), Iraq (N = 1137), Laos (N = 593), Thailand (N = 622), and Somalia (N = 707) were tested for hepatitis B virus (HBV) DNA and hepatitis C virus (HCV) RNA. The HBV DNA (genotypes A, B, C, and G) was detected in 12.1% of samples negative for anti-HBs. Highest HBV prevalence was found among Hmong; lowest among Bhutanese. The HCV RNA (genotypes 1a, 1b, 1c, 3b, 6n, and 6m) was detected in 1.3% of the samples. Highest HCV prevalence was found among Hmong from Thailand; lowest among Iraqis. Screening specific refugee groups at high risk for viral hepatitis infections will identify infected individuals who could benefit from referral to care and treatment and prevent further transmissions.

Laboratory-based surveillance for hepatitis E virus infection, United States, 2005-2012

Clinicians should consider this virus in the differential diagnosis of hepatitis, regardless of patient travel history.

Evaluation of viral heterogeneity using next-generation sequencing, end-point limiting-dilution and mass spectrometry

Hepatitis C Virus sequence studies mainly focus on the viral amplicon containing the Hypervariable region 1 (HVR1) to obtain a sample of sequences from which several population genetics parameters can be calculated. Recent advances in sequencing methods allow for analyzing an unprecedented number of viral variants from infected patients and present a novel opportunity for understanding viral evolution, drug resistance and immune escape. In the present paper, we compared three recent technologies for amplicon analysis: (i) Next-Generation Sequencing; (ii) Clonal sequencing using End-point Limiting-dilution for isolation of individual sequence variants followed by Real-Time PCR and sequencing; and (iii) Mass spectrometry of base-specific cleavage reactions of a target sequence. These three technologies were used to assess intra-host diversity and inter-host genetic relatedness in HVR1 amplicons obtained from 38 patients (subgenotypes 1a and 1b). Assessments of intra-host diversity varied greatly between sequence-based and mass-spectrometry-based data. However, assessments of inter-host variability by all three technologies were equally accurate in identification of genetic relatedness among viral strains. These results support the application of all three technologies for molecular epidemiology and population genetics studies. Mass spectrometry is especially promising given its high throughput, low cost and comparable results with sequence-based methods.

Coordinated evolution of the hepatitis B virus polymerase

The detection of compensatory mutations that abrogate negative fitness effects of drug-resistance and vaccine-escape mutations indicates the important role of epistatic connectivity in evolution of viruses, especially under the strong selection pressures. Mapping of epistatic connectivity in the form of coordinated substitutions should help to characterize molecular mechanisms shaping viral evolution and provides a tool for the development of novel anti-viral drugs and vaccines. We analyzed coordinated variation among amino acid sites in 370 the hepatitis B virus (HBV) polymerase sequences using Bayesian networks. Among the HBV polymerase domains the spacer domain separating terminal protein from the reverse-transcriptase domain, showed the highest network centrality. Coordinated substitutions preserve the hydrophobicity and charge of Spacer. Maximum likelihood estimates of codon selection showed that Spacer contains the highest number of positively selected sites. Identification of 67% of the domain lacking an ordered structure suggests that Spacer belongs to the class of intrinsically disordered domains and proteins whose crucial functional role in the regulation of transcription, translation and cellular signal transduction has only recently been recognized. Spacer plays a central role in the epistatic network associating substitutions across the HBV genome, including those conferring viral virulence, drug resistance and vaccine escape. The data suggest that Spacer is extensively involved in coordination of HBV evolution.

Transmission of hepatitis B virus from an orthopedic surgeon with a high viral load

BACKGROUND

During the evaluation of a needle-stick injury, an orthopedic surgeon was found to be unknowingly infected with hepatitis B virus (HBV) (viral load >17.9 million IU/mL). He had previously completed two 3-dose series of hepatitis B vaccine without achieving a protective level of surface antibody. We investigated whether any surgical patients had acquired HBV infection while under his care.

METHODS

A retrospective cohort study of all patients who underwent surgery by the surgeon was conducted. Patients were notified of their potential exposure and need for testing, and samples with positive HBV loads underwent DNA sequencing. Characteristics of the surgical procedures for the cohort were evaluated.

RESULTS

A total of 232 (70.7%) of potentially exposed patients consented to testing; 2 were found to have acute infection and 6 had possible transmission (evidence of past exposure without risk factors). Genome sequence analysis of HBV DNA from the infected surgeon and patients with acute infection revealed genetically related virus (>99.9% nucleotide identity). Only age was found to be statistically different between those with confirmed or possible HBV transmission and those who remained susceptible to HBV.

CONCLUSIONS

We documented HBV transmission during orthopedic surgery to 2 patients from a surgeon with HBV. This investigation highlights the importance of evaluating individuals who do not respond to 2 series of HBV vaccination, the increased risk of HBV transmission from providers with high viral loads, and the need to evaluate the clinical practice of providers with HBV and implement appropriate procedure-based practice restrictions.

Transmission of hepatitis B virus associated with assisted monitoring of blood glucose at an assisted living facility in New York State

BACKGROUND

Hepatitis B virus (HBV) transmission has been reported after patient-to-patient blood exposure during assisted monitoring of blood glucose (AMBG). Three assisted-living facility (ALF) residents who underwent AMBG developed acute HBV infection (HBVI) within 10 days. We investigated HBV transmission and implemented preventive measures.

METHODS

A retrospective cohort study was conducted. Infection control practices were assessed. HBVI screening was conducted for all staff and epidemiologically linked residents. Viral DNA sequences were compared for a subset of isolates.

RESULTS

Lancing devices and glucometers were shared among residents without proper sanitization. Serologic testing of all 34 residents with diabetes and 12 epidemiologically linked residents present during the exposure period detected 6 residents with diabetes with current HBVI and 4 residents with diabetes and 1 epidemiologically linked resident with previous HBVI. A cohort study of 32 individuals with diabetes identified AMBG as a significant risk factor for HBVI (relative risk, 6.7; 95% confidence interval, 1.7-26.3). Viral DNA sequences for 5 AMBG-exposed residents' isolates were identical, suggesting a common source.

CONCLUSIONS

AMBG was significantly associated with HBVI in ALF residents with diabetes. Despite clear preventive recommendations, bloodborne pathogen transmission continues to occur in the setting of AMBG. Strengthening direct care provider, infection preventionist, and health department partnerships with ALFs is crucial to ensure safe AMBG practices and prevent HBV transmission.

Hepatitis B outbreak associated with a hematology-oncology office practice in New Jersey, 2009

BACKGROUND

Transmission of bloodborne pathogens due to breaches in infection control is becoming increasingly recognized as greater emphasis is placed on reducing health care-associated infections. Two women, aged 60 and 77 years, were diagnosed with acute hepatitis B virus (HBV) infection; both received chemotherapy at the same physician's office. Due to suspicion of health care-associated HBV transmission, a multidisciplinary team initiated an investigation of the hematology-oncology office practice.

METHODS

We performed an onsite inspection and environmental assessment, staff interviews, records review, and observation of staff practices. Patients who visited the office practice between January 1, 2006 and March 3, 2009 were advised to seek testing for bloodborne pathogens. Patients and medical providers were interviewed. Specimens from HBV-infected patients were sent to the Centers for Disease Control and Prevention for HBV DNA testing and phylogenic analysis.

RESULTS

Multiple breaches in infection control were identified, including deficient policies and procedures, improper hand hygiene, medication preparation in a blood processing area, common-use saline bags, and reuse of single-dose vials. The office practice was closed, and the physician's license was suspended. Out of 2,700 patients notified, test results were available for 1,394 (51.6%). Twenty-nine outbreak-associated HBV cases were identified. Specimens from 11 case-patients demonstrated 99.9%-100% nucleotide identity on phylogenetic analysis.

CONCLUSION

Systematic breaches in infection control led to ongoing transmission of HBV infection among patients undergoing invasive procedures at the office practice. This investigation underscores the need for improved regulatory oversight of outpatient health care settings, improved infection control and injection safety education for health care providers, and the development of mechanisms for ongoing communication and cooperation among public health agencies.

Primer Extension Enrichment Reaction (PEER): a new subtraction method for identification of genetic differences between biological specimens

We developed a conceptually new subtraction strategy for the detection and isolation of target DNA and/or RNA from complex nucleic acid mixtures, called Primer Extension Enrichment Reaction (PEER). PEER uses adapters and class IIS restriction enzymes to generate tagged oligonucleotides from dsDNA fragments derived from specimens containing an unknown target ('tester'). Subtraction is achieved by selectively disabling these oligonucleotides by extension reaction using ddNTPs and a double stranded DNA template generated from a pool of normal specimens ('driver'). Primers that do not acquire ddNTP are used to capture and amplify the unique target DNA from the original tester dsDNA. We successfully applied PEER to specimens containing known infectious agents (Hepatitis B Virus and Walrus Calicivirus) and demonstrated that it has higher efficiency than the best comparable technique. The strategy used for PEER is versatile and can be adapted for the identification of known and unknown pathogens and mutations, differential expression studies and other applications that allow the use of subtractive strategies.

New Calicivirus isolated from walrus

The nucleotide sequence and genome organization of a new member of Caliciviridae was determined. Cell culture inoculated with fecal matter from walrus was used to recover fragments of a new virus by Suppression Subtractive Hybridization (SSH). The isolate was identified as a member of the Vesivirus genus of Caliciviridae and designated the name Walrus Calicivirus (WCV). Sets of PCR primers spanning the entire putative genome were designed using known sequences of other vesiviruses. The assembled genome was 8289 nucleotides (nt) long and shared no more than 87% identity with sequences of the other members of the genus Vesivirus. The largest open reading frame (ORF1) between positions 4-5646 encoded a polyprotein. ORF2, found at position 5652-7778, encoded a putative capsid protein. ORF3 overlapped ORF2 and encoded a small basic protein. Comparative analysis of multiple caliciviral capsid proteins was performed to propose a uniform capsid structural organization for this viral family.

Characterization of spo0A homologues in diverse Bacillus and Clostridium species identifies a probable DNA-binding domain

Spo0A is a phosphorylation-activated transcription factor of Bacillus subtilis. It is a member of the response regulator superfamily of bacterial signal transduction proteins and controls many of the changes in gene expression that occur during the transition into stationary phase and during the initiation of sporulation. To identify the domains of Spo0A most critical for determining its structural and functional features, presumptive homologues of the spo0A gene were characterized in a collection of eight Bacillus species and six Clostridium species representing phylogenetically diverse members of these genera. An alignment of the partial or complete DNA sequences of these homologues revealed three regions of especially high conservation in the effector domain. We speculate that the most highly conserved of these corresponds to the recognition helix of a putative helix-turn-helix motif, and, therefore, represents the actual DNA-containing surface of the protein. In the case of homologues identified in Bacillus anthracis and Clostridium acetobutylicum and retrieved by polymerase chain reaction amplification, we confirmed by gene-disruption analysis that the homologue actually is required for initiation of sporulation. Apparent homologues of the B. subtilis spoIVB gene were also discovered immediately upstream from the spo0A homologues in all Bacillus and Clostridium species examined. The discovery of homologues of B. subtilis sporulation genes in these diverse species implies that the gene products required for specifying pathways of sporulation-specific gene activation and for determining key morphogenetic changes may be highly conserved and suggests that an approach similar to that undertaken here might be used as a general strategy to retrieve and compare their gene sequences. Exhaustive efforts to detect a spo0A-like gene in non-endospore formers, including close relatives of Bacillus such as Listeria and Staphylococcus, were uniformly unsuccessful, suggesting that regulation of gene activity during the transition into stationary phase mediated by Spo0A-like proteins may be exclusive to the endospore-forming bacteria.