International review of blood donation nucleic acid amplification testing

BACKGROUND AND OBJECTIVES

Nucleic acid amplification testing (NAT), in blood services context, is used for the detection of viral and parasite nucleic acids to reduce transfusion-transmitted infections. This project reviewed NAT for screening blood donations globally.

MATERIALS AND METHODS

A survey on NAT usage, developed by the International Society of Blood Transfusion Working Party on Transfusion-transmitted Infectious Diseases (ISBT WP-TTID), was distributed through ISBT WP-TTID members. Data were analysed using descriptive statistics.

RESULTS

Forty-three responses were received from 32 countries. Increased adoption of blood donation viral screening by NAT was observed over the past decade. NAT-positive donations were detected for all viruses tested in 2019 (proportion of donations positive by NAT were 0.0099% for human immunodeficiency virus [HIV], 0.0063% for hepatitis C virus [HCV], 0.0247% for hepatitis B virus [HBV], 0.0323% for hepatitis E virus [HEV], 0.0014% for West Nile virus [WNV] and 0.00005% for Zika virus [ZIKV]). Globally, over 3100 NAT-positive donations were identified as NAT yield or solely by NAT in 2019 and over 22,000 since the introduction of NAT, with HBV accounting for over half. NAT-positivity rate was higher in first-time donors for all viruses tested except WNV. During 2019, a small number of participants performed NAT for parasites (Trypanosoma cruzi, Babesia spp., Plasmodium spp.).

CONCLUSION

This survey captures current use of blood donation NAT globally. There has been increased NAT usage over the last decade. It is clear that NAT contributes to improving blood transfusion safety globally; however, there is a need to overcome economic barriers for regions/countries not performing NAT.

End of selection criteria based on sexual orientation: An international symposium on alternatives to donation deferral

BACKGROUND AND OBJECTIVES

Until recently, gay, bisexual and other men who have sex with men (MSM) were deferred from donating blood for 3-12 months since the last male-to-male sexual contact. This MSM deferral has been discontinued by several high-income countries (HIC) that now perform gender-neutral donor selection.

MATERIALS AND METHODS

An international symposium (held on 20-04-2023) gathered experts from seven HICs to (1) discuss how this paradigm shift might affect the mitigation strategies for transfusion-transmitted infections and (2) address the challenges related to gender-neutral donor selection.

RESULTS

Most countries employed a similar approach for implementing a gender-neutral donor selection policy: key stakeholders were consulted; the transition was bridged by time-limited deferrals; donor compliance was monitored; and questions or remarks on anal sex and the number and/or type of sexual partners were often added. Many countries have now adopted a gender-neutral approach in which questions on pre- and post-exposure prophylaxis for human immunodeficiency virus (HIV) have been added (or retained, when already in place). Other countries used mitigation strategies, such as plasma quarantine or pathogen reduction technologies for plasma and/or platelets.

CONCLUSION

The experience with gender-neutral donor selection has been largely positive among the countries covered herein and seems to be acceptable to stakeholders, donors and staff. The post-implementation surveillance data collected so far appear reassuring with regards to safety, although longer observation periods are necessary. The putative risks associated with HIV antiretrovirals should be further investigated.

An international review of the characteristics of viral nucleic acid-amplification testing (NAT) reveals a trend towards the use of smaller pool sizes and individual donation NAT

BACKGROUND AND OBJECTIVES

Nucleic acid-amplification testing (NAT) is used for screening blood donations/donors for blood-borne viruses. We reviewed global viral NAT characteristics and NAT-yield confirmatory testing used by blood operators.

MATERIALS AND METHODS

NAT characteristics and NAT-yield confirmatory testing used during 2019 was surveyed internationally by the International Society of Blood Transfusion Working Party Transfusion-Transmitted Infectious Diseases. Reported characteristics are presented herein.

RESULTS

NAT was mainly performed under government mandate. Human immunodeficiency virus (HIV), hepatitis C virus (HCV) and hepatitis B virus (HBV) NAT was performed on all donors and donation types, while selective testing was reported for West Nile virus, hepatitis E virus (HEV), and Zika virus. Individual donation NAT was used for HIV, HCV and HBV by ~50% of responders, while HEV was screened in mini-pools by 83% of responders performing HEV NAT. Confirmatory testing for NAT-yield samples was generally performed by NAT on a sample from the same donation or by NAT and serology on samples from the same donation and a follow-up sample.

CONCLUSION

In the last decade, there has been a trend towards use of smaller pool sizes or individual donation NAT. We captured characteristics of NAT internationally in 2019 and provide insights into confirmatory testing approaches used for NAT-yields, potentially benefitting blood operators seeking to implement NAT.

Automating Model Comparison in Factor Graphs

Bayesian state and parameter estimation are automated effectively in a variety of probabilistic programming languages. The process of model comparison on the other hand, which still requires error-prone and time-consuming manual derivations, is often overlooked despite its importance. This paper efficiently automates Bayesian model averaging, selection, and combination by message passing on a Forney-style factor graph with a custom mixture node. Parameter and state inference, and model comparison can then be executed simultaneously using message passing with scale factors. This approach shortens the model design cycle and allows for the straightforward extension to hierarchical and temporal model priors to accommodate for modeling complicated time-varying processes.

Facing difficult but unavoidable choices: Donor blood safety and the deferral of men who have sex with men

Blood service organizations employ various ways to ensure transfusion blood safety, including the testing of all donations for transfusion-transmissible infections (TTI) and the exclusion of donors who are at increased risk of a recent infection. As some TTIs are more common among men who have sex with men (MSM), many jurisdictions (temporarily) defer the donation of blood by sexually active MSM. This boils down to a categorical exclusion of a large group solely on the basis of their sexual orientation, which is seen as unduly discriminatory and stigmatizing. Blood service organizations in the U.K. and the Netherlands have recently changed their deferral policies for MSM. The problem of the MSM deferral involves a conflict between fundamental rights: the right of MSM to equal treatment and the right to health of the recipients of blood and blood products. We distinguish and discuss three broad alternative options to the current categorical deferral of MSM donations: (1) completely abandoning donor selection on the basis of sexual behavior, (2) individual risk assessment of the sexual activities of each potential donor, and (3) individual risk assessment of the sexual activities of MSM only. The new U.K. policy falls within the second category, and the new Dutch policy is in the third category. We argue that each approach comes with moral costs but that the most reasonable option is different from the policies of both the U.K. and the Netherlands.

Estimating the potential to prevent locally acquired HIV infections in a UNAIDS Fast-Track City, Amsterdam

Background:

More than 300 cities including the city of Amsterdam in the Netherlands have joined the UNAIDS Fast-Track Cities initiative, committing to accelerate their HIV response and end the AIDS epidemic in cities by 2030. To support this commitment, we aimed to estimate the number and proportion of Amsterdam HIV infections that originated within the city, from Amsterdam residents. We also aimed to estimate the proportion of recent HIV infections during the 5-year period 2014–2018 in Amsterdam that remained undiagnosed.

Methods:

We located diagnosed HIV infections in Amsterdam using postcode data (PC4) at time of registration in the ATHENA observational HIV cohort, and used HIV sequence data to reconstruct phylogeographically distinct, partially observed Amsterdam transmission chains. Individual-level infection times were estimated from biomarker data, and used to date the phylogenetically observed transmission chains as well as to estimate undiagnosed proportions among recent infections. A Bayesian Negative Binomial branching process model was used to estimate the number, size, and growth of the unobserved Amsterdam transmission chains from the partially observed phylogenetic data.

Results:

Between 1 January 2014 and 1 May 2019, there were 846 HIV diagnoses in Amsterdam residents, of whom 516 (61%) were estimated to have been infected in 2014–2018. The rate of new Amsterdam diagnoses since 2014 (104 per 100,000) remained higher than the national rates excluding Amsterdam (24 per 100,000), and in this sense Amsterdam remained a HIV hotspot in the Netherlands. An estimated 14% [12–16%] of infections in Amsterdan MSM in 2014–2018 remained undiagnosed by 1 May 2019, and 41% [35–48%] in Amsterdam heterosexuals, with variation by region of birth. An estimated 67% [60–74%] of Amsterdam MSM infections in 2014–2018 had an Amsterdam resident as source, and 56% [41–70%] in Amsterdam heterosexuals, with heterogeneity by region of birth. Of the locally acquired infections, an estimated 43% [37–49%] were in foreign-born MSM, 41% [35–47%] in Dutch-born MSM, 10% [6–18%] in foreign-born heterosexuals, and 5% [2–9%] in Dutch-born heterosexuals. We estimate the majority of Amsterdam MSM infections in 2014–2018 originated in transmission chains that pre-existed by 2014.

Conclusions:

This combined phylogenetic, epidemiologic, and modelling analysis in the UNAIDS Fast-Track City Amsterdam indicates that there remains considerable potential to prevent HIV infections among Amsterdam residents through city-level interventions. The burden of locally acquired infection remains concentrated in MSM, and both Dutch-born and foreign-born MSM would likely benefit most from intensified city-level interventions.

Funding:

This study received funding as part of the H-TEAM initiative from Aidsfonds (project number P29701). The H-TEAM initiative is being supported by Aidsfonds (grant number: 2013169, P29701, P60803), Stichting Amsterdam Dinner Foundation, Bristol-Myers Squibb International Corp. (study number: AI424-541), Gilead Sciences Europe Ltd (grant number: PA-HIV-PREP-16-0024), Gilead Sciences (protocol numbers: CO-NL-276-4222, CO-US-276-1712, CO-NL-985-6195), and M.A.C AIDS Fund.

Balancing non-discriminatory donor selection and blood safety in the Netherlands: Evaluation of an individual risk assessment of sexual behavior

BACKGROUND

To better balance the safety of the blood supply and the inclusion of men who have sex with men (MSM), further improvements are needed to the risk management strategy employed in the Netherlands to reduce transfusion-transmissible infections (TTIs). A gender-neutral individual risk assessment could provide a solution by determining donor eligibility based on sexual behaviors known to increase the risk of TTIs. Our objective is to estimate the proportion of blood donors that would be deferred by such an assessment, as well as their discomfort answering such questions.

STUDY DESIGN AND METHODS

Two surveys were distributed in May 2020 to assess sexual behavior in blood donors in the last 4, 6, and 12 months, as well as their discomfort reporting such information. A combination of both surveys measured the extent to which discomfort was associated with reporting sexual behavior. A high-risk sexual behavior pattern was defined as having had multiple sexual partners and having engaged in anal sex, without consistent condom use.

RESULTS

Of all 2177 participating whole blood donors, 0.8% report engaging in high-risk sexual behaviors over the last 4 months and would therefore be ineligible to donate. When accounting for the additional proportion of donors that reported such questions would stop them from donating, 2.0% and 3.2% of female and male donors, respectively, would be lost.

DISCUSSION

Gender-neutral eligibility criteria based on high-risk sexual behaviors may reduce the overall number of eligible donors in the Netherlands, but could make blood donation more accessible to a broader group of donors.

Active Inference and Epistemic Value in Graphical Models

The Free Energy Principle (FEP) postulates that biological agents perceive and interact with their environment in order to minimize a Variational Free Energy (VFE) with respect to a generative model of their environment. The inference of a policy (future control sequence) according to the FEP is known as Active Inference (AIF). The AIF literature describes multiple VFE objectives for policy planning that lead to epistemic (information-seeking) behavior. However, most objectives have limited modeling flexibility. This paper approaches epistemic behavior from a constrained Bethe Free Energy (CBFE) perspective. Crucially, variational optimization of the CBFE can be expressed in terms of message passing on free-form generative models. The key intuition behind the CBFE is that we impose a point-mass constraint on predicted outcomes, which explicitly encodes the assumption that the agent will make observations in the future. We interpret the CBFE objective in terms of its constituent behavioral drives. We then illustrate resulting behavior of the CBFE by planning and interacting with a simulated T-maze environment. Simulations for the T-maze task illustrate how the CBFE agent exhibits an epistemic drive, and actively plans ahead to account for the impact of predicted outcomes. Compared to an EFE agent, the CBFE agent incurs expected reward in significantly more environmental scenarios. We conclude that CBFE optimization by message passing suggests a general mechanism for epistemic-aware AIF in free-form generative models.

Many but small HIV-1 non-B transmission chains in the Netherlands

OBJECTIVE

The aim of this study was to investigate introductions and spread of different HIV-1 subtypes in the Netherlands.

DESIGN

We identified distinct HIV-1 transmission chains in the Netherlands within the global epidemic context through viral phylogenetic analysis of partial HIV-1 polymerase sequences from individuals enrolled in the ATHENA national HIV cohort of all persons in care since 1996, and publicly available international background sequences.

METHODS

Viral lineages circulating in the Netherlands were identified through maximum parsimony phylogeographic analysis. The proportion of HIV-1 infections acquired in-country among heterosexuals and MSM was estimated from phylogenetically observed, national transmission chains using a branching process model that accounts for incomplete sampling.

RESULTS

As of 1 January 2019, 2589 (24%) of 10 971 (41%) HIV-1 sequenced individuals in ATHENA had non-B subtypes (A1, C, D, F, G) or circulating recombinant forms (CRF01AE, CRF02AG, CRF06-cpx). The 1588 heterosexuals were in 1224, and 536 MSM in 270 phylogenetically observed transmission chains. After adjustments for incomplete sampling, most heterosexual (75%) and MSM (76%) transmission chains were estimated to include only the individual introducing the virus (size = 1). Onward transmission occurred mostly in chains size 2-5 amongst heterosexuals (62%) and in chains size at least 10 amongst MSM (64%). Considering some chains originated in-country from other risk-groups, 40% (95% confidence interval: 36-44) of non-B-infected heterosexuals and 62% (95% confidence interval: 49-73) of MSM-acquired infection in-country.

CONCLUSION

Although most HIV-1 non-B introductions showed no or very little onward transmission, a considerable proportion of non-B infections amongst both heterosexuals and MSM in the Netherlands have been acquired in-country.

Chance-Constrained Active Inference

Active inference (ActInf) is an emerging theory that explains perception and action in biological agents in terms of minimizing a free energy bound on Bayesian surprise. Goal-directed behavior is elicited by introducing prior beliefs on the underlying generative model. In contrast to prior beliefs, which constrain all realizations of a random variable, we propose an alternative approach through chance constraints, which allow for a (typically small) probability of constraint violation, and demonstrate how such constraints can be used as intrinsic drivers for goal-directed behavior in ActInf. We illustrate how chance-constrained ActInf weights all imposed (prior) constraints on the generative model, allowing, for example, for a trade-off between robust control and empirical chance constraint violation. Second, we interpret the proposed solution within a message passing framework. Interestingly, the message passing interpretation is not only relevant to the context of ActInf, but also provides a general-purpose approach that can account for chance constraints on graphical models. The chance constraint message updates can then be readily combined with other prederived message update rules without the need for custom derivations. The proposed chance-constrained message passing framework thus accelerates the search for workable models in general and can be used to complement message-passing formulations on generative neural models.

Hepatitis C Virus Transmission Among Men Who Have Sex With Men in Amsterdam: External Introductions May Complicate Microelimination Efforts

BACKGROUND

It is unclear whether unrestricted access and high uptake of direct-acting antivirals (DAAs) is sufficient to eliminate hepatitis C virus (HCV) in high-risk populations such as men who have sex with men (MSM). This study presents historic trends and current dynamics of HCV transmission among MSM in Amsterdam based on sequence data collected between 1994 and 2019.

METHODS

Hypervariable region 1 sequences of 232 primary HCV infections and 56 reinfections were obtained from 244 MSM in care in Amsterdam. Maximum-likelihood phylogenies were constructed for HCV genotypes separately, and time-scaled phylogenies were constructed using a Bayesian coalescent approach. Transmission clusters were determined by Phydelity and trends in the proportion of unclustered sequences over time were evaluated using logistic regression.

RESULTS

Seventy-six percent (218/288) of sequences were part of 21 transmission clusters and 13 transmission pairs. Transmission cluster sizes ranged from 3 to 44 sequences. Most clusters were introduced between the late 1990s and early 2010s and no new clusters were introduced after 2012. The proportion of unclustered sequences of subtype 1a, the most prevalent subtype in this population, fluctuated between 0% and 20% in 2009-2012, after which an increase occurred from 0% in 2012 to 50% in 2018.

CONCLUSIONS

The proportion of external introductions of HCV infections among MSM in Amsterdam has recently increased, coinciding with high DAA uptake. Frequent international transmission events will likely complicate local microelimination efforts. Therefore, international collaboration combined with international scale-up of prevention, testing, and treatment of HCV infections (including reinfections) is warranted, in particular for local microelimination efforts.

Variational Message Passing and Local Constraint Manipulation in Factor Graphs

Accurate evaluation of Bayesian model evidence for a given data set is a fundamental problem in model development. Since evidence evaluations are usually intractable, in practice variational free energy (VFE) minimization provides an attractive alternative, as the VFE is an upper bound on negative model log-evidence (NLE). In order to improve tractability of the VFE, it is common to manipulate the constraints in the search space for the posterior distribution of the latent variables. Unfortunately, constraint manipulation may also lead to a less accurate estimate of the NLE. Thus, constraint manipulation implies an engineering trade-off between tractability and accuracy of model evidence estimation. In this paper, we develop a unifying account of constraint manipulation for variational inference in models that can be represented by a (Forney-style) factor graph, for which we identify the Bethe Free Energy as an approximation to the VFE. We derive well-known message passing algorithms from first principles, as the result of minimizing the constrained Bethe Free Energy (BFE). The proposed method supports evaluation of the BFE in factor graphs for model scoring and development of new message passing-based inference algorithms that potentially improve evidence estimation accuracy.

Recently acquired HIV infections and associated factors among men who have sex with men diagnosed at Dutch sexual health centres

INTRODUCTION

Surveillance for recent HIV infections was implemented at Dutch sexual health centres (SHCs) for planning and evaluation of HIV prevention initiatives. The study objective is twofold: (1) to explore trends in recent HIV infections and associated socio-demographic and behavioural risk factors among men who have sex with men (MSM )attending SHCs, to gain insight into subgroups at risk for acquiring HIV and(2) to illustrate how comparison with different reference groups affect associations with these risk factors.

METHODS

Residual plasma or serum samples from MSM newly HIV diagnosed at SHCs in 2014-2017 were tested with an avidity assay. Multinomial regression was used to analyse risk factors for recent HIV infections among MSM with established HIV infections among MSM and with HIV-negative MSM as reference groups.

RESULTS

Of newly diagnosed MSM, 33% were classified as recent HIV infection with avidity testing. Combining HIV-negative test results with avidity outcomes resulted in 54% recent infections. Recent infection was associated with having an STI in the past, multiple partners and condom use for both reference groups of MSM. Additionally, relative to the HIV-negative MSM, recent infection was associated with education and having a non-Western origin. In contrast, relative to MSM with established HIV infections, recent infection was associated with Western origin.

CONCLUSION

Our results suggest ongoing but declining transmission of HIV and high uptake of HIV testing among MSM visiting SHCs. The identification of risk factors for recent infections can help healthcare professionals to target subgroups eligible for PrEP or condom use promotion. Differentiation by the reference group in explanatory models for recent infections is important as different risk factors were identified. Likely, associations relative to HIV-negative MSM follow those of acquiring HIV infection in general, whereas the comparison with the established HIV infection reference rather reflects the frequent testing behaviour of subgroups of MSM.

No increased risk of transfusion-transmissible infections after tattooing, body piercing, or acupuncture among blood donors in the Netherlands

BACKGROUND

In the Netherlands, needle-related events (NREs) including tattoos, piercings, and acupuncture are a reason for temporary blood donor deferral. This study aims to evaluate whether donors with recent NREs had a higher risk of transfusion-transmissible infections (TTIs) compared to donors without recent NREs.

STUDY DESIGN AND METHODS

Data from 2006 through 2015 on all blood donation attempts in the Netherlands were collected. Multivariate regression models (for repeated measurements) were used to assess the associations between recent NREs and the acquisition of TTIs. Posttest counseling data were used to determine the most likely risk factor in TTI-positive new and repeat donors.

RESULTS

Recent NREs were documented in 97,518 out of 9,266,036 (1.1%) donation attempts; 14,097 (14.5%) NREs resulted in NRE-based donor deferral. Recent NREs reported pre-donation were not associated with an increased risk for TTIs. A total of 29 out of 287 TTI-positive donors (11 repeat donors, 18 new donors) reported a recent NRE pre- and/or post-donation. Recent NREs, all needle-stick injuries, were the likely route of transmission in 12 out of 287 (4.2%) of TTI-positive donors. The donor health questionnaire (DHQ) identified only 1 out of 12 TTI-linked NREs. Non-return after NRE deferral, any deferral, or no deferral was 24, 15, and 5%, respectively.

DISCUSSION

Recent tattoos, body piercings, or acupuncture were not associated with an increased risk for TTIs in Dutch donors. Given the lower return rates of donors following a temporary NRE-based deferral, we advocate ending blood donor deferral policies for acupuncture, tattooing, and body piercings, but not needle-stick injuries, in countries where these practices can be considered safe.

2017 European guideline for the screening, prevention and initial management of hepatitis B and C infections in sexual health settings

This guideline updates the 2010 European guideline for the management of hepatitis B and C virus infections. It is primarily intended to provide advice on testing, prevention and initial management of viral hepatitis B and C for clinicians working in sexual health clinical settings in European countries. The guideline is in a new question and answer format based on clinical situations, from which population/intervention/comparison/outcome questions were formulated. Updates cover areas such as epidemiology, point-of-care tests for hepatitis B, hepatitis C risk and 'chemsex', and HIV pre-exposure prophylaxis and hepatitis B. We have also included a short paragraph on hepatitis E noting there is no evidence for sexual transmission. The guideline has been prepared in accordance with the Europe protocol for production available at http://www.iusti.org/regions/europe/pdf/2017/ProtocolForProduction2017.pdf.

Prevalence, determinants and genetic diversity of hepatitis C virus in the multi-ethnic population living in Suriname

Little is known about the epidemiology of HCV in Suriname, a former Dutch colony in South America. To study the prevalence, determinants and genetic diversity of HCV, a one-month survey was conducted at the only Emergency Department in the capital Paramaribo. Participants (≥18 years) completed an interviewer-led standardized HCV risk-factor questionnaire, were tested for HCV-antibodies, and if positive also for HCV RNA. The overall HCV prevalence was 1.0% (22/2128 participants; 95%CI 0.7-1.5). Male sex (OR=4.11; 95%CI 1.30-13.01), older age (OR=1.06 per year increase; 95%CI 1.04-1.09), Javanese ethnicity (OR=7.84; 95%CI 3.25-18.89) and cosmetic tattooing (OR=31.7; 95%CI 3.25-323.87) were independently associated with HCV-infection. Phylogenetic analysis revealed six distinct HCV subtypes, all HCV-genotype 2 (HCV-2): subtype 2f (also circulating in Indonesia) plus five yet unassigned HCV-2 subtypes exclusively linked to Suriname.

Incidence and duration of hepatitis E virus infection in Dutch blood donors

BACKGROUND

The incidence of hepatitis E virus (HEV) infection in the Netherlands is high. Blood donors are not routinely screened for HEV infection, but since January 2013, donations used for the production of solvent/detergent (S/D)-treated plasma have been screened for HEV RNA.

STUDY DESIGN AND METHODS

Donations were screened for HEV RNA in pools of 96 and 192 donations. In addition, all donations made between 60 days before and after each HEV RNA-positive donation were tested individually for HEV RNA and anti-HEV immunoglobulin G.

RESULTS

The screening of 59,474 donations between January 2013 and December 2014 resulted in identification of 45 HEV RNA-positive donations (0.076%) from 41 donors. HEV RNA loads ranged from 80 to 2.3 × 10(6) IU/mL. The number of positive donations increased significantly over time (p = 0.03). Thirty-three of 90 donations made up to 60 days before or after HEV RNA-positive donations were positive when tested individually, while they had not been detected in the pool screening. The mean duration of HEV viremia in the healthy blood donor is estimated to be 68 days.

CONCLUSION

The incidence of HEV infection in the Netherlands is high and increased during the study period. In 2013 and 2014, HEV RNA was detected in 1 per 762 donations intended for production of S/D plasma.

Extended-spectrum β-lactamase-producing Enterobacteriaceae in hospital food: a risk assessment

OBJECTIVE

Determine the prevalence of extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae (ESBL-PE) contamination of food and colonization of food handlers in a hospital kitchen and compare retrieved ESBL-PE strains with patient isolates.

DESIGN

Cross-sectional study.

SETTING

A 2,200-bed tertiary care university hospital in Switzerland.

PARTICIPANTS

Food handlers.

METHODS

Raw and prepared food samples were obtained from the hospital kitchen, with a comparator group from local supermarkets. Fecal samples collected from food handlers and selectively pre-enriched homogenized food samples were inoculated onto selective chromogenic media. Phenotypic confirmation of ESBL production was performed using the double disk method. Representative ESBL-PE were characterized using polymerase chain reaction (PCR) and sequencing for blaCTX-M, blaSHV, and blaTEM genes, and Escherichia coli strains were typed using phylotyping, repetitive element palindromic PCR, and multilocus sequence typing. Meat samples were screened for antibiotic residues using liquid chromatography time-of-flight mass spectrometry.

RESULTS

Sixty (92%) of the raw chicken samples were ESBL-PE positive, including 30 (86%) of the hospital samples and all supermarket samples. No egg, beef, rabbit, or cooked chicken samples were ESBL-PE positive. No antibiotic residues were detected. Six (6.5%) of 93 food handlers were ESBL-PE carriers. ESBL-PE strains from chicken meat more commonly possessed blaCTX-M-1 and blaCTX-M-2, whereas blaCTX-M-14 and blaCTX-M-15 were predominant among strains of human origin. There was partial overlap in the sequence type of E. coli strains of chicken and human origin. No E. coli ST131 strains or blaCTX-M-15 genes were isolated from meat.

CONCLUSIONS

Although there is significant ESBL-PE contamination of delivered chicken meat, current preventive strategies minimize risks to food handlers, hospital staff, and patients.

Female sex and IL28B, a synergism for spontaneous viral clearance in hepatitis C virus (HCV) seroconverters from a community-based cohort

BACKGROUND & AIMS

Since acute hepatitis C virus (HCV) infection is often asymptomatic, it is difficult to examine the rate and determinants of spontaneous clearance. Consequently, these studies are subject to bias, which can potentially lead to biased rates of viral clearance and risk estimates. We evaluated determinants of spontaneous HCV clearance among HCV seroconverters identified in a unique community-based cohort.

METHODS

Subjects were 106 drug users with documented dates of HCV seroconversion from the Amsterdam Cohort Study. Logistic regression was used to examine sociodemographic, behavioral, clinical, viral and host determinants, measured around acute infection, of HCV clearance.

RESULTS

The spontaneous viral clearance rate was 33.0% (95% confidence interval (CI) 24.2-42.8). In univariate analyses female sex and fever were significantly associated with spontaneous clearance. The favorable genotypes for rs12979860 (CC) and rs8099917 (TT) were associated with spontaneous clearance, although borderline significant. In multivariate analysis, females with the favorable genotype for rs12979860 (CC) had an increased odds to spontaneously clear HCV infection (adjusted OR 6.62, 95% 2.69-26.13), whereas females with the unfavorable genotype were as likely as men with the favorable and unfavorable genotype to clear HCV. Chronic Hepatitis B infection and absence of HIV coinfection around HCV seroconversion also favor HCV clearance.

CONCLUSIONS

This study shows that co-infection with HIV and HBV and genetic variation in the IL28B region play an important role in spontaneous clearance of HCV. Our findings suggest a possible synergistic interaction between female sex and IL28B in spontaneous clearance of HCV.

Phylogenetic analysis of acute hepatitis C virus genotype 4 infections among human immunodeficiency virus-positive men who have sex with men in Germany

BACKGROUND

An ongoing HCV epidemic currently affects a growing proportion of HIV-positive men who have sex with men (MSM) in Europe. Recently in the North-Rhine region of Germany, we have observed an increase in acute HCV infections of genotype 4 (HCV-4).

AIMS

To characterize the current spread of HCV-4 among German MSM using a molecular epidemiological approach.

METHODS

Patient characteristics and sera were collected for HIV-positive MSM diagnosed with acute HCV-4 infections in the North-Rhine region (n=14), Hamburg (n=14), Frankfurt (n=4) and Berlin (n=4). Part of the HCV NS5B region (436 bp) was amplified, sequenced and compared with HCV-4 sequences from HIV-positive Dutch, English and French MSM (n=50) as well as unrelated HCV risk groups (n=61).

RESULTS

NS5B sequences were obtained from 35/36 (97%) of German cases, all of which were HCV subtype 4d (HCV-4d). The phylogenetic analysis of HCV sequences revealed two MSM-specific HCV-4d clusters of 71 and 12 sequences. All except one of the German MSM belonged to a large MSM-specific HCV cluster containing MSM from all four different European countries. None of the HCV-4 strains circulating among injecting drug users or in HCV-4 endemic areas were part of the MSM-specific clusters.

CONCLUSIONS

HCV rapidly spreads among European HIV-positive MSM through a joint international transmission network, separate from that of injecting drug users. In order to contain this epidemic, non-parenteral routes of transmission, such as unsafe sex, must be taken into consideration and prevention measures should be refocused accordingly.