Molecular evidence for nosocomial transmission of hepatitis C virus in a French hemodialysis unit

Comparison of hepatitis C virus NS5b and 5' noncoding gene sequencing methods in a multicenter study

A national evaluation study was performed in 11 specialized laboratories with the objective of assessing their capacities to genotype hepatitis C virus (HCV) and define the applicability of a given genotyping method. The panel consisted of 14 samples positive for HCV RNA of different genotypes (including 3 samples with two different artificially mixed genotypes) and 1 HCV-negative sample. Seventeen sets of data were gathered from the 11 participating laboratories. The sensitivities ranged from 64.3 to 100% and from 42.7 to 85.7% for the methods that used sequencing of the NS5b region and the 5' noncoding (5' NC) region, respectively. When the data for the artificially mixed samples were excluded, NS5b genotyping gave correct results for 80% of the samples, 1.7% of the samples were misclassified, and 18.3% of the samples had false-negative results. By 5' NC-region genotyping methods, 58.3% of the results were correct, 29.7% were incomplete, 8.3% were misclassifications, 1.2% were false positive, and 2.4% were false negative. Only two procedures based on NS5b sequencing correctly identified one of the three samples with mixtures of genotypes; the other methods identified the genotype corresponding to the strain with the highest viral load in the sample. Our results suggest that HCV 5' NC-region genotyping methods give sufficient information for clinical purposes, in which the determination of the subtype is not essential, and that NS5b genotyping methods are more reliable for subtype determination, which is required in epidemiological studies.

Confirmation of nosocomial hepatitis C virus infection in a hemodialysis unit

OBJECTIVES

To investigate a hepatitis C virus (HCV) outbreak in a hemodialysis unit and determine the source of transmission.

METHODS

We have prospectively investigated the epidemiology of hemodialysis-related HCV infection in a single unit since 1989. In September 2000, acute hepatitis C (AH-C) was diagnosed in 5 patients by alanine aminotransferase elevation and HCV genotype 1b viremia without antibody to HCV. We surveyed the epidemiologic situation and performed polymerase chain reaction sequence analysis of the HCV 5'-noncoding (5'NC) region in the patients for comparison with 9 patients with chronic HCV genotype 1b viremia.

RESULTS

Sequence analysis of the 5'NC region showed the consistency in the 5 independent clones from each AH-C patient and those from each chronic HCV viremia patient and no quasispecies over time in the clones of any of 14 analyzed patients. All AH-C patients had the same sequencing of the 6 variations in the region with the only other patient. A saline ampoule, used for heparin solution during hemodialysis, had a recap function. It was difficult to determine whether the ampoule was new or had already been used. The source-patient often underwent hemodialysis before the AH-C patients and most of their hemodialysis-related medicine was prepared during the source-patient's treatment. These findings suggested a high possibility that the AH-C patients shared a single heparin-saline solution ampoule contaminated by HCV from the source-patient.

CONCLUSION

Nosocomial HCV infection occurred as a result of poor infection control practice when a patient with chronic HCV viremia received treatment prior to other hemodialysis patients.

Genomic and phylogenetic analysis of hepatitis C virus isolates: a survey of 535 strains circulating in southern France

The present study examines the distribution of Hepatitis C virus (HCV) genotypes in Marseille, France in 2001-2002 and evaluates the efficiency of two in house direct sequence PCR protocols based on 5'NC analysis or NS5B analysis. By 5'NC sequencing, the distribution of 535 HCV strains derived from patients attending gastroenterology and AIDS referral centers, or dialysis units was as follows: 33% were infected by genotype 1a; 26% by 1b; 7% by 2; 22% by 3a; 10.7% by 4. In univariate analysis, HCV distribution was associated with age and source of infection, whereas in multivariate analysis only injecting drug use was an independent determinant for genotype distribution. Among the 535 specimens submitted to 5'NC direct sequencing, 18% could not be classified accurately into subtypes. A subset of 187 samples was amplified efficiently and sequenced by targeting the NS5B region of the viral genome. The two methods yielded concordant results in 70% of cases. Specimens unsubtypeable or misclassified most frequently by 5'NC analysis were type 1b and subtypes 2a/2c and 4a/4c. The data show that 5'NC direct sequence analysis is a sensitive method to identify genotypes in all cases, but that it can lead to subtyping misclassification (in particular, subtype 1b and 1a) or doubtful results (in particular subtypes 2a/2c and 4a/4c). Conversely, NS5B direct sequence assay, based on phylogenetic analysis, allowed better discrimination between subtypes. These two approaches are complementary and should be made available in clinical laboratories to ensure a reliable survey of HCV strains.

Managing occupational risks for hepatitis C transmission in the health care setting

Hepatitis C virus (HCV) infection is a significant contemporary health problem in the United States and elsewhere. Because it is primarily transmitted via blood, hepatitis C infection presents risks for both nosocomial transmission to patients and occupational spread to health care workers. Recent insights into the pathogenesis, immunopathogenesis, natural history, and treatment of infection caused by this unique flavivirus provide a rationale for the use of new strategies for managing occupational hepatitis C infections when they occur. This article reviews this developing information. Recently published data demonstrate success rates in the treatment of "acute hepatitis C syndrome" that approach 100\%, and although these studies are not directly applicable to all occupational infections, they may provide important clues to optimal management strategies. In addition, the article delineates approaches to the prevention of occupational exposures and also addresses the difficult issue of managing HCV-infected health care providers. The article summarizes currently available data about the nosocomial epidemiology of HCV infection and the magnitude of risk and discusses several alternatives for managing exposure and infection. No evidence supports the use of immediate postexposure prophylaxis with immunoglobulin, immunomodulators, or antiviral agents. Based on the very limited data available, the watchful waiting and preemptive therapy strategies described in detail in this article represent reasonable interim approaches to the complex problem of managing occupational HCV infections, at least until more definitive data are obtained.

Determining hepatitis C genotype by analyzing the sequence of the NS5b region

Assays to determine the hepatitis C virus (HCV) genotype have recently become useful for clinical decision making and may be suitable for epidemiological investigations, such as identifying HCV outbreaks in a given population. Molecular assays are the most common diagnostic tools for HCV genotyping. This study compares two genome typing assays, one, the Trugene 5'NC genotyping kit, uses the sequence of the 5' non-coding (5'NC) region and the other, a non-commercial assay, uses the non-structural 5b (NS5b) region. Serum samples from 203 chronically HCV-infected patients were tested. The 5'NC and the NS5b assays were both very effective in identifying the genotype (99 and 98.5%) and the results with the two methods were always concordant for the genotype. The NS5b analysis permitted the identification of the subtype in all samples, whereas the 5'NC region assay did not in 33% of samples. The NS5b analysis showed that one patient had a mixed infection with HCV subtypes 1a and 2c, while the 5'NC assay did not. It is concluded that phylogenetic analysis using both the 5'NC and the NS5b regions are reliable and convenient methods for HCV typing in clinical practice. But analysis of the NS5b region may be more useful for tracing the source of an HCV infection.

Nosocomial transmission of hepatitis C virus associated with the use of multidose saline vials

OBJECTIVE

To identify the source of an outbreak of acute hepatitis C virus (HCV) infection among 3 patients occurring within 8 weeks of hospitalization in the same ward of a Florida hospital during November 1998.

DESIGN

A retrospective cohort study was conducted among 41 patients hospitalized between November 11 and 19, 1998. Patients' blood was tested for antibodies to HCV, and HCV RNA-positive samples were genotyped and sequenced.

RESULTS

Of the 41 patients, 24 (59%) participated in the study. HCV genotype lb infections were found in 5 patients. Three of 4 patients who received saline flushes from a multidose saline vial on November 16 had acute HCV infection, whereas none of the 9 patients who did not receive saline flushes had HCV infection (P = .01). No other significant exposures were identified. The HCV sequence was available for 1 case of acute HCV and differed by a single nucleotide (0.3%) from that of the indeterminate case.

CONCLUSION

This outbreak of HCV probably occurred when a multidose saline vial was contaminated with blood from an HCV-infected patient Hospitals should emphasize adherence to standard procedures to prevent blood-borne infections. In addition, the use of single-dose vials or prefilled saline syringes might further reduce the risk for nosocomial transmission of blood-borne pathogens.

Long-term impact of renal transplantation on liver fibrosis during hepatitis C virus infection

BACKGROUND & AIMS

During hepatitis C virus (HCV) infection, liver fibrosis progression after renal transplantation remains controversial. The aim of this cohort study with controls was to compare liver histopathologic features during HCV infection between renal transplant recipients and matched groups of hemodialyzed patients or controls without renal disease and untreated for HCV.

METHODS

Each renal transplant recipient (group 1, n = 30) was matched at first liver biopsy (LB) using the main factors known to influence progression of fibrosis with one HCV hemodialyzed patient (group 2, n = 30) and one HCV-infected patient (nonhemodialyzed, nontransplanted; group 3, n = 30). Patients from group 1 were also matched with those of group 3 on the time between 2 consecutive LBs performed 37 months apart. LBs were evaluated according to the Knodell index, METAVIR score, and rate of fibrosis progression per year (fibrosis unit).

RESULTS

The rate of fibrosis progression per year between the first and second LBs was significantly lower (P = 0.03) in group 1 (0.067; 95% confidence interval: -0.05, 0.18) than group 3 (0.20; 95% confidence interval: 0.13, 0.26). At the second LB, the Knodell index and activity or fibrosis in METAVIR were lower in group 1 than group 3 (4.2 +/- 0.4 vs. 7.5 +/- 0.6, 0.5 +/- 0.1 vs. 1.3 +/- 0.2, and 1.4 +/- 0.2 vs. 2.3 +/- 0.2 respectively, P < 0.01).

CONCLUSIONS

Our study suggests that liver fibrosis progression is low in most HCV-infected renal transplant recipients with moderate liver disease at baseline.

High prevalence of hepatitis C infection among patients receiving hemodialysis at an urban dialysis center

OBJECTIVE

To determine the seroprevalence and risk factors for hepatitis C virus (HCV) infection among patients at an urban outpatient hemodialysis center.

METHODS

This was a cross-sectional study of 227 patients undergoing hemodialysis at the Rogosin Kidney Center on December 15, 1998, with a response rate of 90% (227 of 253). Laboratory records were used to retrieve the total number of blood transfusions received and serologic study results. Univariate and multivariate analyses were used to examine the relationship among HCV serostatus, patient demographics, and HCV risk factors (eg, intravenous drug use [IVDU], intranasal cocaine use, multiple sexual partners, comorbidities, length of time receiving hemodialysis, and total number of blood transfusions received).

RESULTS

The seroprevalence of antibody to HCV (anti-HCV) was 23.3% (53 of 227) in the population. In univariate analysis, factors associated with HCV seropositivity included male gender, younger age, history of IVDU, history of intranasal cocaine use, history of multiple sexual partners, human immunodeficiency virus coinfection, increased time receiving dialysis, history of renal transplant, and positive antibody to hepatitis B core antigen. Multivariate logistic regression analysis showed that longer duration receiving dialysis and a history of IVDU were the only risk factors that remained independently associated with HCV seropositivity

CONCLUSIONS

HCV is markedly more common in our urban cohort of patients receiving hemodialysis compared with patients receiving dialysis nationally and is associated with a longer duration of receiving dialysis and a history of IVDU. Stricter and more frequent enforcement of universal precautions may be required in hemodialysis centers located in areas with a high prevalence of HCV infection or IVDU among the general population.

Impact of hepatitis B and hepatitis C virus infections in a hematology-oncology unit at a children's hospital in Nicaragua, 1997 to 1999

The risk of acquiring both hepatitis B virus (HBV) and hepatitis C virus (HCV) infections in patients with hematological-oncological disorders has been documented. However, the impact and risk factors for such infections from different geographical areas vary, and the use of both immunological and molecular assays to determine HCV infections has been our approach. Children from a hematology-oncology unit (HOU) in Nicaragua were studied for both HBV and HCV serological markers; studies for the latter used both immunological (anti-HCV) and molecular (HCV RNA) assays. The children from the HOU included patients with leukemia, lymphoma, other neoplasias, and anemia and a smaller group with other hematological diseases. As a control group, children from other units at the same hospital were enrolled, as well as health care workers attending both patient populations. Pertinent clinical and personal data for each child at the HOU were obtained for statistical analysis. Of the 625 children from the HOU enrolled in this study 53.3% were infected with HCV and 29.4% had a prior or present HBV infection. In the child patient control group 3.2% had HBV markers and all were negative for HCV. The group of children with leukemia had the highest infection rate for both HBV and HCV. However, the determination of anti-HCV was found to have an overall low sensitivity in children from HOU, and a retest consisting of a molecular assay to determine HCV RNA was performed to better establish the total number of HCV-infected subjects in this group. The highest independent risk factor for infection was hospitalization. The very high prevalence rates for both HBV and HCV infection in this patient group indicate an urgent need to implement better control of known risk factors and to consider the use of both immunological and molecular assays for HCV diagnostic purposes.

Use of phylogenetic analysis of hepatitis C virus (HCV) hypervariable region 1 sequences to trace an outbreak of HCV in an autodialysis unit

Hemodialysis patients are at high risk of infection by hepatitis C virus (HCV). The aim of this study was to investigate an HCV outbreak that occurred in an autodialysis unit by using epidemiological and molecular methods. Seroconversion to HCV antibody (anti-HCV) was observed in two patients over an 18-month period; two other patients had previously been recorded as anti-HCV positive. All four patients involved in the outbreak were tested for HCV RNA, and hepatitis C genotype determination was accomplished by a reverse hybridization assay. Furthermore, part of hypervariable region 1 (HVR1) of the hepatitis C genome was amplified and sequenced in samples from all HCV RNA-positive patients. Phylogenetic analysis of the nucleotide sequences obtained was carried out in order to investigate any possible epidemiological linkages among patients. The nucleotide sequences of the HVR1 regions of both newly infected patients were found to be identical to sequences of samples from previously recorded anti-HCV-positive original patients, suggesting that they were infected by the same isolate. Molecular and epidemiological analysis suggested that nosocomial patient-to-patient transmission was the most likely explanation for the virus spread in the autodialysis unit under study.

Hepatitis C: an epidemiological review

The aim of the study was to analyse the current literature regarding the mode of transmission of HCV and its global prevalence in different groups of people. A systematic review of the literature on the epidemiology of hepatitis C from 1991 to 2000 using computerized bibliographic databases which include Medline, Current Content and Embase. The prevalence of hepatitis C virus (HCV) varies tremendously in different parts of the world, with the highest incidence in the Eastern parts of the globe compared with the Western parts. Furthermore, certain groups of individuals such as intravenous drug users are at increased risk of acquiring this disease irrespective of the geographical location. Although the main route of transmission is via contaminated blood, curiously enough in up to 50% of the cases no recognizable transmission factor/route could be identified. Therefore, a number of other routes of transmission such as sexual or household exposure to infected contacts have been investigated with conflicting results. Hepatitis C infection is an important public health issue globally. Better understanding of routes of transmission will help to combat the spread of disease. In order to prevent a world wide epidemic of this disease, urgent measures are required to (i) develop a strategy to inform and educate the public regarding this disease and (ii) expedite the efforts to develop a vaccine.

Hepatitis C in a ward for cystic fibrosis and diabetic patients: possible transmission by spring-loaded finger-stick devices for self-monitoring of capillary blood glucose

OBJECTIVE

To identify the routes of transmission in a nosocomial outbreak of hepatitis C virus (HCV) infection.

DESIGN

Epidemiological investigation, including screening for HCV of hospitalized patients, and a retrospective cohort study, review of hygiene and medical practices, and molecular comparison of HCV isolates.

SETTING

A specialized care unit for cystic fibrosis (CF) and diabetic patients at an acute-care facility in the south of France.

RESULTS

Of the 57 CF patients (age in 1995: 2-28 years), 38 (66.7%) were tested and 22 (57.9%) were anti-HCV positive. Eight (50%) of 16 patients with anti-HCV antibody tested by polymerase chain reaction were viremic. No patients had received blood products or had any history of intravenous drug use. All 18 (100%) patients with CF who had ever undergone self-monitoring of capillary blood glucose in the unit were anti-HCV positive, compared to 4 (20%) of 20 who had not (relative risk, 5.0; 95% confidence interval, 2.1-12.0). Seventy (39.5%) of the patients with diabetes were screened for anti-HCV; 12 (18.8%) tested positive, with 3 (25%) positive for HCV-RNA. Patients with diabetes had routine capillary blood glucose monitoring while hospitalized and shared with CF patients the same spring-triggered devices for capillary blood glucose monitoring. The disposable platform of the devices was not changed between patient use. All HCV isolates belonged to the type 1, subtype b, and phylogenetic analysis showed a close homology by sequencing of NS5b and E2/HVR regions.

CONCLUSION

As reported earlier for the hepatitis B virus, shared spring-triggered devices for capillary blood glucose monitoring by finger puncture may transmit HCV. Strict application of Standard Precautions procedures is warranted in any healthcare setting.

Prevalence of infected patients and understaffing have a role in hepatitis C virus transmission in dialysis

To assess hepatitis C virus (HCV) incidence rates and identify determinants of infection among hemodialysis patients, a multicenter study was conducted in 58 units in ITALY: An initial seroprevalence survey was conducted among 3,492 patients already on hemodialysis therapy as of January 1997 and among an additional 434 patients who began dialysis up to January 1998. HCV antibodies were assessed by third-generation enzyme immunoassays. Patients testing seronegative at baseline were enrolled into a 1-year incidence study with serological follow-up at 6 and 12 months. For patients who seroconverted, an HCV RNA assay was performed on stored baseline samples to confirm new infection. A nested case-control study was subsequently performed to investigate potential risk factors. For each incident case, three controls negative for both HCV antibodies and HCV RNA were randomly selected. At enrollment, HCV seroprevalence was 30.0%. During follow-up, 23 new HCV cases were documented, with a cumulative incidence of 9.5 cases/1,000 patient-years. By logistic regression analysis, an increased risk for HCV infection emerged for patients attending the dialysis units with a high prevalence of HCV-infected patients at baseline (odds ratio [OR], 4.6) and for those attending units with a low personnel-patient ratio (OR, 5.4). Among extradialysis factors, a history of surgical intervention in the previous 6 months (OR, 16.7) significantly increased HCV risk. These findings suggest that the combination of understaffing and a high level of infected patients in the dialysis setting increases the risk for HCV nosocomial transmission. This is likely related to an increased likelihood for breaks in infection control measures.

The emerging nosocomial pathogens Cryptosporidium, Escherichia coli O157:H7, Helicobacter pylori, and hepatitis C: epidemiology, environmental survival, efficacy of disinfection, and control measures

New and emerging infectious diseases pose a threat to public health and may be responsible for nosocomial outbreaks. Cryptosporidium parvum and Escherichia coli are gastrointestinal pathogens that have caused nosocomial infections via person-to-person transmission, environmental contamination, or contaminated water or food. Helicobacter pylori has been transmitted via inadequately disinfected endoscopes. Finally, hepatitis C may be acquired by healthcare personnel by percutaneous or mucous membrane exposure to blood or between patients by use of contaminated blood products or via environmental contamination. Rigorous adherence to Standard Precautions, Contact Precautions for patients with infectious diarrhea, disinfection of environmental surfaces, and appropriate disinfection of endoscopes are adequate to prevent nosocomial acquisition of these pathogens.

Hepatitis C virus transmission in a pediatric oncology ward: analysis of an outbreak and review of the literature

Hospital-related hepatitis C virus (HCV) infections continue to occur even after the introduction of blood donor screening. We report an outbreak of HCV in nine patients of a pediatric oncology ward in 1996/1997. Sequencing of the hypervariable genomic region 1 (HVR1) of the E2/NS1 region showed near identity between HCV isolates from these patients as evidence for infection with the same virus. Despite a detailed and careful investigation, the source of infection and the mode of virus transmission could not be established. Based on a review of the current literature about nosocomial HCV infection and HCV infection in children, hypotheses for possible means of transmission in this outbreak are discussed.