Nosocomial transmission of hepatitis C virus during contrast-enhanced computed tomography scanning

Outbreak of hepatitis C virus infections originating from a breach in safe injection practices before contrast-enhanced computed tomography scanning

Four patients who underwent contrast-enhanced computed tomography (CT) scanning were infected with hepatitis C virus from a contaminated multi-dose vial of NaCl. The outbreak likely occurred due to a breach in safe injection practices, resulting in contamination of the vial. Not all patients exposed to the same vial were infected. The uneven distribution of infections could be attributed to a stochastic effect of a low infectious dose. This implies that outbreak investigations need to be extended to all patients scheduled before and after the first identified infected patient to confirm or rule out nosocomial transmission.

Detection of hepatitis C virus in an exhumed body identified the origin of a nosocomial transmission that caused multiple fatal diseases

BACKGROUND

Medico-legal conflicts arise when it is difficult to prove the cause of nosocomial infections.

AIM

To report an outbreak of patient-to-patient transmission of hepatitis C virus (HCV) through the repeated use of a multi-dose saline flask during the rinsing of central venous catheters.

METHODS

Blood samples were taken from each patient for the comparative analysis of their HCV RNA strains. No samples were available for one patient who died before the investigation started. Despite the known lability of HCV RNA, the body was exhumed four months after burial and postmortem samples were collected. HCV RNA was extracted successfully from liver and spleen samples. Genotyping of all the HCV strains was performed by sequence analysis of the 5'NC untranslated region, the E1 core conserved region and the E1/E2 hypervariable region.

FINDINGS

Forensic investigators retraced the route used by two ward nurses, when saline catheter flushes were given to 14 patients with each nurse administering to seven patients. The comparative phylogenetic analysis of all case strains identified the deceased patient as the source of contamination to five patients.

CONCLUSIONS

This study highlights the value of sequence analysis as a tool for solving medico-legal conflicts. The High Court of Justice found that a health worker's re-use of a contaminated needle resulted in the nosocomial transmission of HCV.

Cellular immune response to hepatitis-C-virus in subjects without viremia or seroconversion: is it important?

Hepatitis C Virus (HCV) causes chronic infection and represents a global health burden. To date, there is no licensed vaccine for HCV. The high viral replication rate and the existence of several HCV genotypes and quasispecies hamper the development of an effective universal vaccine. In this regard, the current HCV vaccine candidates show genotype-specific protection or narrow cross reactivity against other genotypes. Importantly, HCV spontaneous clearance occurs in 15-50 % of infected subjects, indicating that natural resistance to chronic infection exists. This phenomenon was demonstrated among humans and chimpanzees and continues to motivate researchers attempting to develop an effective HCV vaccine. However, what constitutes a protective immune response or correlate of protection against HCV infection is still vague. Additionally, the mechanisms behind successful HCV clearance suggest the coordination of several arms of the immune system, with cell-mediated immunity (CMI) playing a crucial role in this process. By contrast, although neutralizing antibodies have been identified, they are isolate-specific and poorly correlate with viral clearance. Antigen-specific CD4 T cells, instead, correlate with transient decline in HCV viremia and long-lasting control of the infection. Unfortunately, HCV has been very successful in evading host immune mechanisms, leading to complications such as liver fibrosis, cirrhosis and hepatocellular carcinoma. Interestingly, CMI to HCV antigens were shown among exposed individuals without viremia or seroconversion, suggesting the clearance of prior HCV infection(s). These individuals include family members living with HCV-infected subjects, healthcare workers, IV drug users, and sexual contacts. The correlates of protection could be closely monitored among these individuals. This review provides a summary of HCV-specific immune responses in general and of CMI in particular in these cohorts. The importance of these CMI responses are discussed.

Epidemiology of hepatitis C in Europe

The advent of potent and safe direct-acting antivirals against the hepatitis C virus has the potential of fulfilling the dream of eliminating this infection and its impact on global public health. However, even if effective drugs are at hand, most patients remain unaware of their infection, which may be recognized only in late stages when dire complications have occurred. Europe is not spared by this scourge, with its estimated 19,000,000 persons infected, and knowledge of the epidemiology of HCV and its drivers is a critical tool in fighting this virus. A thorough review is provided on the extent of the HCV epidemic across Europe, with a discussion of the most important subgroups affected, and of the risk factors of infection, both traditional and new.

An observational study to evaluate the efficiency and safety of ioversol pre-filled syringes compared with ioversol bottles in contrast-enhanced examinations

BACKGROUND

The use of pre-filled syringes for contrast media (CM) administration allows efficient and optimized workflow during radiologic diagnostic procedures, and reduces the risk of contamination, providing benefits for both patients and healthcare workers.

PURPOSE

To compare the efficiency and safety of ioversol (Optiray(TM)) bottles and pre-filled syringes in clinical practice.

MATERIAL AND METHODS

This was an observational, non-interventional, prospective, multicenter study conducted at 72 centers in Germany. Patients undergoing contrast-enhanced computed tomography (CT) examinations with ioversol were enrolled. The use of ioversol bottles and pre-filled syringes in the diagnostic procedure was recorded in terms of efficiency (residual volume, re-use of CM) and safety (adverse events [AEs]).

RESULTS

A total of 10,836 patients were enrolled and included in this study. Ioversol bottles and syringes were used in 72% and 28% of cases, respectively. Analysis of the volume of CM in bottles before and after examinations, together with the volume used during the examination, suggested that in 22.5% of cases a new bottle was connected during the procedure. Further analysis revealed that in 80.2% of cases, the remaining volume of CM in the bottles could potentially be used for subsequent investigations, compared with <1% of cases for pre-filled syringes. For the total study population, AEs and serious AEs were reported in 30 (0.28%) and four (0.037%) patients, respectively, with no significant difference observed between ioversol bottles and syringes.

CONCLUSION

Administration of ioversol for contrast-enhanced CT examinations is associated with a low incidence of AEs and is generally safe and well tolerated. Ioversol pre-filled syringes were associated with lower residual volumes and less potential re-use compared with bottles.

Patient-to-patient transmission of hepatitis C virus (HCV) during colonoscopy diagnosis

Background

No recognized risk factors can be identified in 10-40% of hepatitis C virus (HCV)-infected patients suggesting that the modes of transmission involved could be underestimated or unidentified. Invasive diagnostic procedures, such as endoscopy, have been considered as a potential HCV transmission route; although the actual extent of transmission in endoscopy procedures remains controversial. Most reported HCV outbreaks related to nosocomial acquisition have been attributed to unsafe injection practices and use of multi-dose vials. Only a few cases of likely patient-to-patient HCV transmission via a contaminated colonoscope have been reported to date. Nosocomial HCV infection may have important medical and legal implications and, therefore, possible transmission routes should be investigated. In this study, a case of nosocomial transmission of HCV from a common source to two patients who underwent colonoscopy in an endoscopy unit is reported.

Results

A retrospective epidemiological search after detection of index cases revealed several potentially infective procedures: sample blood collection, use of a peripheral catheter, anesthesia and colonoscopy procedures. The epidemiological investigation showed breaches in colonoscope reprocessing and deficiencies in the recording of valuable tracing data. Direct sequences from the NS5B region were obtained to determine the extent of the outbreak and cloned sequences from the E1-E2 region were used to establish the relationships among intrapatient viral populations. Phylogenetic analyses of individual sequences from viral populations infecting the three patients involved in the outbreak confirmed the patient pointed out by the epidemiological search as the source of the outbreak. Furthermore, the sequential order in which the patients underwent colonoscopy correlates with viral genetic variability estimates.

Conclusions

Patient-to-patient transmission of HCV could be demonstrated although the precise route of transmission remained unclear. Viral genetic variability is proposed as a useful tool for tracing HCV transmission, especially in recent transmissions.

Infection control guidelines for prevention of health care-associated transmission of hepatitis B and C viruses

Viral hepatitis was first identified as an occupational hazard for health care workers more than 60 years ago. For the past few decades, hepatitis B has been one of the most significant occupational infectious risks for health care providers. With the increasing prevalence of hepatitis C infections around the world, occupational transmission of this flavivirus from infected patients to their providers has also become a significant concern. Several factors influence the risk for occupational blood-borne hepatitis infection among health care providers, among them: the prevalence of infection among the population served, the infection status of the patients to whom workers are exposed (ie, the source patient's circulating viral burden), the types and frequencies of parenteral and mucosal exposures to blood and blood-containing body fluids, and whether the patient or provider has been immunized with the hepatitis B vaccine. This article reviews patient-to-provider, patient-to-patient, and provider-to-patient transmission of hepatitis B and C in the health care setting. Current prevention strategies, precautions, and guidelines are discussed.

[Acute hepatitis due to hepatitis C virus infection in the adult population]

INTRODUCTION

Knowledge of acute hepatitis C infection (AHC) is important to design effective prevention and treatment strategies. The aim of this study was to determine the clinical and epidemiological features and outcomes of patients diagnosed with AHC.

METHODS

A retrospective clinical-epidemiological study was carried out in adult patients diagnosed with AHC between 2000 and 2008 in our hospital.

RESULTS

Sixteen patients were diagnosed. The most probable source of transmission was intravenous drug abuse in four patients, a percutaneous injury in three healthcare workers, a medical procedure in three patients and sexual contact in two patients. The source of infection was unknown in four patients. Diagnosis was based on acute clinical symptoms in eight patients, follow-up of healthcare injury in three patients and was fortuitous in five patients. Nine patients showed severe symptoms, while seven patients were asymptomatic or had mild symptoms. The four patients who received treatment were cured. Of the 12 patients that did not receive treatment, the disease became chronic in 58.3%. Progression to chronic disease was more frequent in patients without jaundice than in those with jaundice (85.7% vs 16.7%).

CONCLUSIONS

Because medical procedures are still a risk factor for hepatitis C infection, active surveillance is required as well as compliance with prevention measures against parenteral transmission. The percentage of patients with jaundice who progress to chronic disease is low and consequently the start of treatment in these patients could be delayed according to their clinical course.

Evidence of hepatitis C virus-specific interferon gamma-positive T cells in health care workers in an infectious disease department

BACKGROUND

Few studies are available on possible hepatitis C virus (HCV)-specific T-cell immune response in health care workers (HCWs) involved in the care of patients with HCV infection. We aimed to investigate whether a HCV-specific interferon (IFN)-gamma T-cell response, known to be involved in infection resolution, was present in those HCWs involved in the management of patients with persistent HCV infection.

METHODS

Our study involved 30 subjects, classified as group A (20 consecutive patients, 16 males and 4 females, with histologically proven chronic hepatitis), or group B (10 HCWs, 7 males and 3 females, with at least 7 years of health care experience and HCV-RNA and anti-HCV negative). As a control group, we used 10 blood samples from healthy donors at a blood donor center (group C). HCV-RNA was measured by real-time polymerase chain reaction. Blood samples (at least 35 mL) were collected from all group A and group B subjects in our hospital. Specific IFN-gamma was stimulated with HCV pool peptides (core, 2 microg/mL), with influenza Mp peptides used as a positive control.

RESULTS

Levels of HCV-specific IFN-gamma-positive cells were higher in the HCWs (group B) compared with the infected patients (group A) and healthy blood donors (group C) (Mann-Whitney U test, P < .001).

CONCLUSION

A clinically silent persistent exposure to HCV, through some as-yet undetermined mechanism, may induce a virus-specific IFN-gamma-producing CD8(+) T-cell response in healthy aviremic HCWs. This finding suggests that possible unapparent parenteral routes may stimulate host defenses with no evidence of hepatitis.

Transmission of hepatitis C virus in an orthopedic hospital ward

Healthcare-associated infections with hepatitis C virus (HCV) hitherto have been observed mainly in hemodialysis settings as well as in hematology and oncology wards. In this communication, molecular and epidemiologic investigations to elucidate an HCV outbreak in an orthopedic ward are reported. One hundred and thirty-five patients hospitalized in the ward and 104 staff members were tested. In addition to extensive epidemiologic reviews and hygienic inspections, direct sequencing of HCV PCR fragments and phylogenetic analysis of more than 300 partial HCV sequences obtained by end-point limiting-dilution real-time PCR assay were carried out. Six patients were infected with very closely related HCV variants. Patient-to-patient spread of the virus was inferred to have started from one patient with previous HCV infection to the other five patients during their hospital stay. Inspections did not reveal substantial breaches in basic infection control practices and did not identify a specific activity that might have led to nosocomial transmission. As a result of the investigations, the hospital corrected the documentation of all medical and nursing activities undertaken in the ward, abandoned the use of all multidose saline and other medication vials, and included explicitly recommendations for the safe preparation and administration of injectable drugs into internal infection control guidelines. Thereafter, no further nosocomial transmissions of HCV have been recorded in the orthopedic ward. The events observed suggest that nosocomial transmission of HCV is not limited to hemodialysis, hematology or oncology settings, and they also reinforce the mandatory adherence to basic infection control practices.

Hygiene precautions and the transmission of infections in radiology

Healthcare-associated infections are a critical challenge for the public health sector. Most are acquired through contact, predominantly with the hands of health care personnel. Hand hygiene, therefore, is the single most effective measure for preventing and controlling infectious diseases. Recently, cases of acute hepatitis C occurred in patients who had undergone contrast-enhanced computed tomography. This was probably related to inadequate handling by health care staff. Rigorous compliance with standard precautions is therefore compulsory even in radiology, a setting traditionally considered at low risk for the transmission of pathogens. Adherence to standard precautions is still poor and the persistence of inappropriate practices responsible for preventable incidents is very common in radiology, often owing to underestimation of risk. Radiology units must promote compliance with correct hand hygiene through appropriate education programmes and provision of adequate areas and hand hygiene products. The evidence base to support the use of alcohol-based hand rub is demonstrating that these formulations are effective in improving hand hygiene compliance and preventing infections.