A comparative pilot study on Gram-negative bacteria contaminating the hands of children living in urban and rural areas of Indonesia versus Germany - A suitable monitoring strategy for diarrhea risk assessment?

Diarrhea is the second leading cause of death mainly effecting young children. Often it is the result of fecal-oral pathogen transmission. We aimed to investigate whether monitoring the prevalence of Gram-negative bacteria on the hands of asymptomatic children is suitable as an indicator of fecal contamination of the environment in their playground. We compared the prevalence of Gram-negative bacteria on the hands of children, who live in the German city of Göttingen, an urban area in a high-income country, with the situation in Medan as an urban area and Siberut as a rural area both in the middle-income country Indonesia. A total of 511 children at the age of 3 months to 14 years were asked to put their thumb print on MacConkey agar, which was used to screen for the presence of Gram-negative bacteria. These were subsequently identified by using MALD-TOF mass spectrometry and classified into the order Enterobacterales, Pseudomonadales, and others. The highest burden of hand contamination was found in children from rural Siberut (66.7%) followed by children from urban Medan (53.9%), and from urban Göttingen (40.6%). In all three study sites, hand contamination was lower in the youngest (<1 year) and oldest age groups (10-14 years) and highest in the age group 5-9 years. Bacteria of the order Enterobacterales possibly indicating fecal contamination were most prevalent in Siberut (85.1%) followed by Medan (62.9%) and Göttingen (21.5%). Most facultative and obligate gastrointestinal pathogens such as Escherichia coli (n = 2) and Providencia rettgeri (n = 7), both being members of the order Enterobacterales, as well as Aeromonas caviae (n = 5), and Vibrio cholerae (n = 1) both belonging to other orders were nearly exclusively identified on the hands of children in Siberut. This result was not surprising, because hygienic conditions were lowest in Siberut. Only one isolate of A. caviae was found in Medan, and no facultative gastrointestinal pathogen was identified on the hands of children from Göttingen. Our pilot study therefore indicates that investigating hands of children for the prevalence of Gram-negative bacteria using selective media are a helpful method to monitor hygienic conditions, and thereby assess the risk for diarrhea-causing bacterial pathogens in the environment.

Comparison and Harmonization of Different Semi-Automated and Automated qRT-PCR Assays in the Assessment of SARS-CoV-2.

In SARS-CoV-2 diagnostics, cycle threshold (Ct) values from qRT-PCRs semi-quantitatively estimate a patient's viral load. However, relevant analytical differences between qRT-PCR assays are often neglected. This study was designed (i) to identify such differences between five commonly used assays and (ii) to demonstrate a straightforward strategy to harmonize them. QRT-PCRs for SARS-CoV-2 were carried out in 85 oropharyngeal swab samples using three fully automated (Alinity m, cobas®6800 and GeneXpert) and two semi-automated (genesig® and RIDA®GENE) assays. Qualitative results (positive/negative) showed excellent comparability between the fully automated assays, but not between the Alinity m and semi-automated methods. Ct values significantly varied between all the methods, with the median values ranging from 22.76 (Alinity m) to 30.89 (RIDA®GENE) and 31.50 (genesig®), indicating the lowest sensitivity for semi-automated methods. Passing-Bablok analysis further revealed systemic biases. Assay-specific viral load concentration calculations-based on generated individual standard curves-resulted in much better comparability between the assays. Applying these calculations, significant differences were no longer detectable. This study highlights relevant analytical differences between SARS-CoV-2 qRT-PCR assays, leading to divergent decisions about the mandatory isolation of infected individuals. Secondly, we propose a strategy to harmonize qRT-PCR assays to achieve better comparability. Our findings are of particular interest for laboratories utilizing different assays.

Comparative Assessment of Sera from Individuals after S-Gene RNA-Based SARS-CoV-2 Vaccination with Spike-Protein-Based and Nucleocapsid-Based Serological Assays.

Due to the beginning of vaccination against COVID-19, serological discrimination between vaccine-associated humoral response and serology-based surveillance of natural SARS-CoV-2 infections as well as breakthrough infections becomes an issue of relevance. Here, we assessed the differentiated effects of the application of an RNA vaccine using SARS-CoV-2 spike protein epitopes on the results of both anti-spike protein-based serology (EUROIMMUN) and anti-nucleocapsid-based serology (VIROTECH). A total of 80 serum samples from vaccinees acquired at different time points after vaccination was assessed. While positive or borderline serological response in the anti-spike protein assay was observed for all samples (90% both IgG and IgA, 6.3% IgA only, 3.8% borderline IgG only), only a single case of a falsely positive IgM was observed for the anti-nucleocapsid assay as expected due to this assay's specificity. Positive anti-spike protein antibodies were already detectable in the second week after the first dose of vaccination, with higher titers after the second dose of the vaccine. In conclusion, the combined application of anti-spike protein-based serology and anti-nucleocapsid-based serology will provide a useful option for the discrimination of vaccination response and natural infection.

HIV-serostatus disclosure in the context of free antiretroviral therapy and socio-economic dependency: experiences among women living with HIV in Tanzania.

The worldwide implementation of free antiretroviral therapy (ART) raised great hopes among policy makers and health organisations about the positive changes it would bring about in attitudes and behaviours towards HIV and AIDS, as well as for infected people's lives. A change in illness perception was anticipated, leading to the hypothesis of a possible change in disclosure rates, patterns and the choice of significant others to inform. In the era of free treatment availability in the United Republic of Tanzania, we examined reasons for disclosure and non-disclosure among HIV-seropositive women enrolled on ART and their choice of significant others to inform. In so doing, we contribute to the necessary yet neglected debate about the social impact of ART on the lives of infected women. The study, for which an ethnographic cross-sectional pilot approach was chosen, was conducted at the Care and Treatment Center (CTC) at Bombo Regional Hospital (BRH) in Tanga city, Tanzania. Data presented here derive from participant observation, questionnaires and semi-structured interviews conducted with 59 HIV-seropositive women on ART. Interestingly, and despite treatment availability, the choice of significant others to inform, as well as reasons for disclosure and non-disclosure, mirror findings from previous studies conducted before the introduction of free ART. The main reason for non-disclosure was fear of discrimination. The hope for social, economic or health support was the main motivation for disclosure, followed by the need for a 'clinic companion' in order to receive ART, as requested by hospital staff. Nevertheless, healthcare staff were not unanimous in thinking that disclosure is always beneficial, thus the recommended extent of disclosure varied. ART and concomitant factors were raised as an entirely new and significant reason for disclosure by interviewees. Finally, findings confirm that despite ART, disclosure remains a highly stressful event for women.

Immunity to Campylobacter: its role in risk assessment and epidemiology.

Acquired immunity is an important factor in the epidemiology of campylobacteriosis in the developing world, apparently limiting symptomatic infection to children of less than two years. However, also in developed countries the highest incidence is observed in children under five years and the majority of Campylobacter infections are asymptomatic, which may be related to the effects of immunity and/or the ingested doses. Not accounting for immunity in epidemiological studies may lead to biased results due to the misclassification of Campylobacter-exposed but apparently healthy persons as unexposed. In risk assessment studies, health risks may be overestimated when immunity is neglected.