Logo: to the web site of Uppsala University

BACKGROUND: Multiple concurrent sexual relationships are one of the major challenges to HIV prevention in Tanzania. This study aims to explore sexual behaviour patterns including the practice of multiple concurrent sexual partnerships in a rural Tanzanian setting.

METHODS: This qualitative study used focus group discussions and in-depth interviews with men and women from the community as well as ethnographic participant observations. The data was collected during 16 months of fieldwork in 2007, 2008, and 2009. The focus group discussions and in-depth interviews were transcribed verbatim and translated into English. The data was analysed through the process of latent content analysis. An open coding coding process was applied to create categories and assign themes.

FINDINGS: Mafiga matatu was an expression used in this society to describe women's multiple concurrent sexual partners, usually three partners, which was described as a way to ensure social and financial security for their families as well as to achieve sexual pleasure. Adolescent initiation ceremonies initiated and conducted by grand mothers taught young women why and how to engage successfully in multiple concurrent sexual relationships. Some men expressed support for their female partners to behave according to mafiga matatu, while other men were hesitant around this behaviour. Our findings indicate that having multiple concurrent sexual partners is common and a normative behaviour in this setting. Economical factors and sexual pleasure were identified as drivers and viewed as legitimate reason for women to have multiple concurrent sexual partnerships.

CONCLUSIONS: Structural changes improving women's financial opportunities and increasing gender equality will be important to enable women to not depend on multiple concurrent sexual partnerships for financial security. Future research should explore how normative sexual behaviour changes as these structural changes take place.

Gulls (Larus spp.) have frequently been reported to carry Escherichia coli exhibiting antimicrobial resistance (AMR E. coli); however, the pathways governing the acquisition and dispersal of such bacteria are not well described. We equipped 17 landfill-foraging gulls with satellite transmitters and collected gull faecal samples longitudinally from four locations on the Kenai Peninsula, Alaska to assess: (a) gull attendance and transitions between sites, (b) spatiotemporal prevalence of faecally shed AMR E. coli, and (c) genomic relatedness of AMR E. coli isolates among sites. We also sampled Pacific salmon (Oncorhynchus spp.) harvested as part of personal-use dipnet fisheries at two sites to assess potential contamination with AMR E. coli. Among our study sites, marked gulls most commonly occupied the lower Kenai River (61% of site locations) followed by the Soldotna landfill (11%), lower Kasilof River (5%) and upper Kenai River (<1%). Gulls primarily moved between the Soldotna landfill and the lower Kenai River (94% of transitions among sites), which were also the two locations with the highest prevalence of AMR E. coli. There was relatively high spatial and temporal variability in AMR E. coli prevalence in gull faeces and there was no evidence of contamination on salmon harvested in personal-use fisheries. We identified E. coli sequence types and AMR genes of clinical importance, with some isolates possessing genes associated with resistance to as many as eight antibiotic classes. Our findings suggest that gulls acquire AMR E. coli at habitats with anthropogenic inputs and subsequent movements may represent pathways through which AMR is dispersed.

Objectives: Accurate and rapid microbiological diagnostics are crucial to tailor treatment and improve outcomes in patients with severe infections. This study aimed to assess blood culture diagnostics in the Nordic countries and to compare them with those of a previous survey conducted in Sweden in 2013. Methods: An online questionnaire was designed and distributed to the Nordic clinical microbiology laboratories (CMLs) (n = 76) in January 2018. Results: The response rate was 64% (49/76). Around-the-clock incubation of blood cultures (BCs) was supported in 82% of the CMLs (40/49), although in six of these access to the incubators around the clock was not given to all of the cabinets in the catchment area, and 41% of the sites (20/49) did not assist with satellite incubators. Almost half (49%, 24/49) of the CMLs offered opening hours for >= 10 h during weekdays, more commonly in CMLs with an annual output >= 30 000 BCs. Still, positive BCs were left unprocessed for 60-70% of the day due to restrictive opening hours. Treatment advice was given by 23% of CMLs (11/48) in >= 75% of the phone contacts. Rapid analyses (species identification and susceptibility testing with short incubation), performed on aliquots from positive cultures, were implemented in 18% of CMLs (9/49). Compared to 2013, species identification from subcultured colonies (<6 h) had become more common. Conclusions: CMLs have taken action to improve aspects of BC diagnostics, implementing satellite incubators, rapid species identification and susceptibility testing. However, the limited opening hours and availability of clinical microbiologists are confining the advantages of these changes. (C) 2021 The Author(s). Published by Elsevier Ltd on behalf of European Society of Clinical Microbiology and Infectious Diseases.

The β-lactam antibiotics are a cornerstone in treating bacterial infections, but the increasing prevalence of antibiotic resistance worldwide threatens their effectiveness. The main driver of β-lactam resistance is the production of β-lactamases, which are bacterial enzymes that inactivate the antibiotic. Moreover, resistance to multiple antibiotic classes is common in β-lactamase producing bacteria, further limiting treatment options. At the same time, few novel antibacterial agents are reaching the market. To address this challenge, antibiotic combination therapy is employed to enhance the effects of existing drugs against multidrug-resistant bacteria. Yet, there is a lack of knowledge regarding which antibiotics to combine to achieve the best effect. The investigations in this thesis evaluate the potential and limitations of combinations involving β-lactams, β-lactamase inhibitors and colistin against multidrug-resistant Enterobacterales in vitro. 

In the first paper, we investigated resistance mechanisms to three commonly used β-lactam/β-lactamase inhibitor combinations (BLBLIs) in an Escherichia coli strain encoding multiple β-lactamases. We found that β-lactamase gene amplifications were a key driver of resistance, with variations in the amplification pattern depending on the BLBLI combination. Clinical resistance could be reached by gene amplifications for ampicillin-sulbactam and piperacillin-tazobactam, whereas ceftazidime-avibactam resistance required multiple genetic changes. 

In the second paper, we evaluated the efficacy of double-carbapenem combinations against E. coli and Klebsiella pneumoniae producing carbapenemases (KPC-2, OXA-48, NDM-1, and NDM-5). Synergistic effects were most commonly observed against OXA-48-producing strains, whereas the efficacy was low against KPC-2 and negligible against NDM producers. 

In the third and fourth papers, we evaluated the antibacterial activity of colistin in combination with BLBLIs. Considering that reduced membrane permeability is associated with decreased susceptibility towards BLBLIs, adding colistin may be beneficial since its membrane-disrupting effect may increase the entry of other drugs. In paper three, we showed synergistic effects with colistin and ceftazidime-avibactam against a KPC-2-producing K. pneumoniae strain with porin deficiencies. However, when systematically assessing the impact of porin loss on the synergistic potential of colistin in combination with BLBLIs in paper four, we did not find any clear association between porin loss and synergy. 

These studies provide insight into the therapeutic potential and limitations of combinations, including β-lactam antibiotics against strains with different setups of resistance genes. More research is required to understand how to best use the newly introduced BLBLI combinations to preserve their activity and enhance the value of the available antibiotics for future generations.