In October 2012, an outbreak of gentamicin-resistant, ciprofloxacin non-susceptible extended-spectrum β-lactamase (ESBL)-producing Klebsiella pneumoniae occurred in a neonatal intensive care unit in Ireland. In order to determine whether the outbreak strain was more widely dispersed in the country, 137 isolates of K. pneumoniae with this resistance phenotype collected from 17 hospitals throughout Ireland between January 2011 and July 2013 were examined. ESBL production was confirmed phenotypically and all isolates were screened for susceptibility to 19 antimicrobial agents and for the presence of genes encoding blaTEM, blaSHV, blaOXA, and blaCTX-M; 22 isolates were also screened for blaKPC, blaNDM, blaVIM, blaIMP and blaOXA-48 genes. All isolates harboured blaSHV and blaCTX-M and were resistant to ciprofloxacin, gentamicin, nalidixic acid, amoxicillin-clavulanate, and cefpodoxime; 15 were resistant to ertapenem, seven to meropenem and five isolates were confirmed as carbapenemase producers. Pulsed-field gel electrophoresis of all isolates identified 16 major clusters, with two clusters comprising 61% of the entire collection. Multilocus sequence typing of a subset of these isolates identified a novel type, ST1236, a single locus variant of ST48. Data suggest that two major clonal groups, ST1236/ST48 (CG43) and ST15/ST14 (CG15) have been circulating in Ireland since at least January 2011.

To investigate the association between, and the reproductive modes of, mycobiont and photobiont in the lichen Parmotrema tinctorum, microsatellite markers (SSR markers) were developed for both bionts and genotypic analysis was performed for thalli in a Pinus thunbergii forest. In a within-thallus analysis, tissue pieces were sampled from many portions within each of five thalli. Within-thallus variation for both mycobiont and photobiont differed among the thalli investigated, suggesting that a single thallus can be derived from either a single mycobiont origin with or without occasional changes in the photobiont, or fusion of several independent thalli. In the within-tree analysis, thalli with the same genotypes were found on individual trees, suggesting the presence of short-distance isidium dispersal. In the within-stand analysis, genotypically similar photobionts tended to be associated with the same mycobiont genotype, suggesting the participation of local dispersal via isidia. The overall index of association (IA) for the mycobiont in the stand probably indicates the dominance of sexual reproduction, in contrast to that of the photobiont, where dominance of asexual reproduction is suggested. IA's of mycobiont and photobiont were also calculated for thalli collected from larger areas, where there is a signature for sexual reproduction for photobiont.

This study represents an analysis of trypanosome strains circulating within a confined location over a short period of time during a sleeping sickness epidemic in S.E. Uganda. A large number of Trypanosoma brucei isolates (88) were collected from a variety of hosts (man, cattle, pigs and tsetse) from villages within a 10 km radius and were analysed for variation in isoenzyme patterns, restriction fragment length polymorphism (RFLP) in repetitive DNA sequences and susceptibility to human serum. The human infective stocks form a clearly distinguishable population when compared with other stocks circulating in the domestic cattle reservoir. The data here support the occurrence of genetic exchange between the cattle stocks while an ‘epidemic’ population structure involving limited genetic exchange is a characteristic of the human infective stocks. Furthermore, it is shown that when both RFLP and isoenzyme analysis are carried out most stocks appear to have individual genotypes. Stocks which were formerly grouped as zymodemes are better considered as a collection of distinct individuals.

Individual animals are often infected not only by different parasite species, but also by multiple genotypes of the same parasite species. Genetic relatedness among parasites sharing a host is expected to modulate their strategies of resource exploitation, growth and virulence. We experimentally examined the effects that genetic diversity and infection intensity had on host mortality, infectivity and growth of the marine trematode Maritrema novaezealandensis in amphipod hosts. The presence of 2 versus 1 parasite genotype during infection did not influence subsequent host mortality, had different effects on infectivity among genotypes and did not influence growth or variation in parasite growth. Density-dependent growth reductions revealed that the number of parasites infecting a host was more important than their genetic relatedness. Temperature, host size, and host sex influenced the degree to which density-dependent factors affected parasite growth. Our results suggest that the effects of parasite relatedness vary among parasite genotypes in this trematode species, and reveal that many factors play an important role during parasite development and transmission.

We present the first parasitological, molecular and longitudinal analysis of an isolated outbreak of malaria. This outbreak occurred on Santiago Island (Republic of Cabo Verde), a region where malaria is hypoendemic and controlled, and thus the population is considered non-immune. Blood samples were collected from the inhabitants over 1 month and during cross-sectional surveys in the following year. The presence and nature of the parasites was determined by PCR. Plasmodium falciparum was the only species detected. Genetic analysis revealed that the circulating parasites were genetically homogeneous, and probably clonal. Gametocytes were found throughout this period. Our data suggest that this represented a focal outbreak, resulting in the infection of at least 40% of the villagers with a clonal parasite line. Thus, P. falciparum infections can persist for at least 1 year in a substantial proportion (10%) of the hosts. Implications for malaria control and the interpretation of epidemiological data are discussed.

Trypanosoma cruzi, the agent of Chagas' disease, exhibits considerable biological variability. Moreover, it has been postulated that populations of this protozoan are subdivided into natural clones, which can be separated from each other by considerable levels of evolutionary divergence. The authors have proposed that this long-term clonal evolution may have a profound impact on Trypanosoma cruzi biological diversity. In order to test this hypothesis, 16 T. cruzi stocks representing 3 major clonal genotypes of the parasite were analysed for 8 different in vitro biological parameters. The overall results show a strong statistical linkage between genetic and biological differences. This is in agreement with the working hypothesis, although a notable biological variability is observable among the stocks of each of the 3 major clonal genotypes. The authors propose that T. cruzi genetic variability must be taken into account in any applied study dealing with this parasite.