Destination shapes antibiotic resistance gene acquisitions, abundance increases, and diversity changes in Dutch travelers

Background Antimicrobial-resistant bacteria and their antimicrobial resistance (AMR) genes can spread by hitchhiking in human guts. International travel can exacerbate this public health threat when travelers acquire AMR genes endemic to their destinations and bring them back to their home countries. Prior studies have demonstrated travel-related acquisition of specific opportunistic pathogens and AMR genes, but the extent and magnitude of travel’s effects on the gut resistome remain largely unknown. Methods Using whole metagenomic shotgun sequencing, functional metagenomics, and Dirichlet multinomial mixture models, we investigated the abundance, diversity, function, resistome architecture, and context of AMR genes in the fecal microbiomes of 190 Dutch individuals, before and after travel to diverse international locations. Results Travel markedly increased the abundance and α-diversity of AMR genes in the travelers’ gut resistome, and we determined that 56 unique AMR genes showed significant acquisition following international travel. These acquisition events were biased towards AMR genes with efflux, inactivation, and target replacement resistance mechanisms. Travel-induced shaping of the gut resistome had distinct correlations with geographical destination, so individuals returning to The Netherlands from the same destination country were more likely to have similar resistome features. Finally, we identified and detailed specific acquisition events of high-risk, mobile genetic element-associated AMR genes including qnr fluoroquinolone resistance genes, blaCTX-M family extended-spectrum β-lactamases, and the plasmid-borne mcr-1 colistin resistance gene. Conclusions Our results show that travel shapes the architecture of the human gut resistome and results in AMR gene acquisition against a variety of antimicrobial drug classes. These broad acquisitions highlight the putative risks that international travel poses to public health by gut resistome perturbation and the global spread of locally endemic AMR genes.

RED-AND-WHITE COW SELECTING FOR MILKABILITY TRAITS AND MONITORING OF KAPPA-CASEIN FORMS AND OTHER GENETIC MARKERS

Изучена эффективность селекции при расширении круга ДНК-маркеров (κ-CN, bGH, PiT-1), а также целесообразность определения критериев оценки изменчивости (кроме генеалогических линий) и при использовании локусов, относимых к QTL-факторам, но с низким полиморфизмом. При существующих темпах быстрого нарастания гомозиготности генетическая изменчивость угрожающе снижается. Это характерно для популяций голштинской породы и крупного рогатого скота «улучшаемых» ею отечественных пород. Проведен поиск ассоциаций с наиболее значимыми признаками селекции в стаде племенного завода красно-пестрой породы. Коровы с гетерозиготным АВ генотипом κ-казеина превосходили сверстниц стада с АА генотипом по удою на 1077 кг молока (P<0,05) и высоте в крестце — на 3,3 см (P<0,01), по МДЖ и МДБ уступали, соответственно, на 0,14 и 0,02%. Выявлено превосходство коров с гетерозиготным генотипом по живой массе во все периоды выращивания телок, снижение возраста их плодотворного осеменения на 1,3 мес. При совершенствовании признаков с использованием генотипов κ-казеина и ряда других локусов обоснована целесообразность отбора и моделирование подбора, а также направленного выведения ремонтных быков. Подчеркнута необходимость дальнейшего изучения функций генов на пути сохранения полезного спектра аллелофонда племенных стад и продолжения эффективной селекции. The efficiency of breeding with the extended DNA marker resources (κ-CN, bGH, and PiT-1) and the effects of reasonable assessment criteria for variability (excluding genealogical lines) at low levels of polymorphism of loci assigned to the QTL factors have been studied. Genetic variability tends to reduce at the current rate of arising homozygosity. It is typical for the Holstein cattle populations and the domestic cattle breeds “improved” by Holsteins. Exploration of associations between selection traits of importance across the Red-and-White cattle in the herd at the breeding enterprise was performed. The milk yield and the sacral height of the cows with k-casein heterozygous AB genotypes were 1077 kg (P<0,05) and 3.3 cm (P<0,01) higher, respectively, than that in their herd peers with genotype AA. With respect to the mass fractions of fat (MFF) and the mass fractions of protein (MFP), their values were 0.14% and 0.02%, respectively, lower. The cows of heterzygous genotype were more efficient in the liveweight during all of the periods of rearing the heifers; reduction in age by 1.3 months at their first effective insemination was recorded. Selecting including target replacement bull selecting and selection modeling are proven reasonable to improve the traits with the use of genotypes at k-casein and other loci. The need of further studying the gene functions is amphasized to preserve the pedigree-cattle allele pool of rare variants important in selective breeding for efficient productivity.