P3-0083 — Annual report 2015
1.
Detection of methicillin-resistant Staphylococcus aureus cattying the mecC gene in human samples in Slovenia

Following the recognition of a mecC MRSA isolate from a patient hospitalized in the northeastern region of Slovenia, a national collection of 395 CA-MRSA isolates from 2005-2013 was screened and it was found that mecC MRSA were present since 2007 but were not recognized until 2013. MRSA isolates harboring mecC gene are primarily community-associated and have been reported in several European countries mainly from humans who had contact with livestock, however they differ from LA-MRSA CC 398. An additional six mecC MRSA strains were found and characterized as ST 130. Two were from healthy people and four from wounds. Animal contact in these patients was lacking. The low oxacillin MIC concentrations and absence of the mecA gene make recognition of these MRSA strains problematic for diagnostic laboratories. In such strains the presence of mecC should be determined.

COBISS.SI-ID: 3854714
2.
Age-related differences in percentages of regulatory and effector T lymphocytes and their subsets in healthy individuals and characteristic STAT1/STAT5 signalling response in helper T lymphocytes

The dynamic process of the development of the immune system can in itself result in age-related immune malfunctions. In this study, we analysed lymphocyte subsets in the peripheral blood of 60 healthy donors, divided into groups of children, adolescents, and adults, focusing on effector (Teff) and regulatory (Treg) T lymphocytes and STAT1/STAT5 signalling response in helper T lymphocytes (Th) in adults, using flow cytometry. Our results demonstrate a decrease in the percentage of total Tregs and an increase in the percentage of total Teffs with age and a consequential immense increase in the Teff/Treg ratio. The increase of Teffs was most apparent in Th1, Th1Th17, and Th17CD161- subsets. Significant Th lymphocyte STAT1 expression differences were observed between children and adolescents, which were associated with the decrease in activated Tregs. Higher expression of STAT1 was found in FoxP3hi than in FoxP3low Th lymphocytes, while significant IL-2 induced STAT5 phosphorylation differences were found among the subsets of Th lymphocytes in adults. Our study demonstrates age-related changes in circulating Teff and Treg, as well as significant differences in STAT5/STAT1 signalling among FoxP3+ Th lymphocytes, providing new advances in the understanding of immunosenescence.

COBISS.SI-ID: 32347353
3.
Bridging epidemiology with population genetics in a low incidence MSM-driven HIV-1 subtype B epidemic in Central Europe

BACKGROUND: The HIV-1 epidemic in Slovenia, a small Central European country, has some characteristics that make it an ideal model to study HIV-1 transmission. The epidemic is predominantly affecting men who have sex with men infected with subtype B (89% of all patients), has a low prevalence (less than 1/1000) and is growing slowly. The aim of the present study was to analyze in detail the evolutionary history and the determinants of transmission. METHODS: A total of 223 partial pol gene sequences from therapy naïve individuals were included, representing 52% of all patients newly diagnosed in 13 years (2000-2012) and analyzed together with genetically similar worldwide sequences, selected in a BLAST search. RESULTS: Combined analysis (maximum likelihood and Bayesian) of HIV-1 transmission chains revealed 8 major clusters (n )= 10 patients), 1 group of 4 patients, 2 trios and 12 transmission pairs, thus leaving only 43 (19.3%) Slovenian patients infected with subtype B without a local epidemiological link, indicating a predominance of local transmission of HIV-1 infection. Bayesian analysis performed on a full set of sequences estimated several introductions of HIV-1 into Slovenia, with the most recent common ancestor (tMRCA) of the earliest Slovenian cluster dated to the late 1980s, although tMRCAs obtained from separate independent analysis of each cluster showed considerably more recent estimates. These findings indicate inconsistencies in molecular clock estimation, which we further explored. We hypothesize that these inconsistent dating estimates across the tree could be caused by an evolutionary rate acceleration of HIV-1 after entering the Slovenia epidemic that is not taken into account by the molecular clock model. It could be caused by a lower transmission rate in this setting, as demonstrated by the low epidemic growth rate estimated by Bayesian skyline plot analysis. CONCLUSIONS: HIV-1 subtype B was introduced into Slovenia at several time points from the late 80s onward. The majority of patients had a local transmission link, indicating a closed HIV community. The observed slower epidemic rate suggests that individuals with a long-lasting infection are the driving force of the epidemic in this region.

COBISS.SI-ID: 31957465
4.
Detection and characterization of a novel reassortant mammalian orthoreovirus in bats in Europe

A renewed interest in mammalian orthoreoviruses (MRVs) has emerged since new viruses related to bat MRV type 3, detected in Europe, were identified in humans and pigs with gastroenteritis. This study reports the isolation and characterization of a novel reassortant MRV from the lesser horseshoe bat (Rhinolophus hipposideros). The isolate, here designated BatMRV1-IT2011, was first identified by electron microscopy and confirmed using PCR and virus-neutralization tests. The full genome sequence was obtained by next-generation sequencing. Molecular and antigenic characterizations revealed that BatMRV1-IT2011 belonged to serotype 1, which had not previously been identified in bats. Phylogenetic and recombination detection program analyses suggested that BatMRV1-IT2011 was a reassortant strain containing an S1 genome segment similar to those of MRV T1/bovine/Maryland/Clone23/59 and C/bovine/ Indiana/MRV00304/2014, while other segments were more similar to MRVs of different hosts, origins and serotypes. The presence of neutralizing antibodies against MRVs has also been investigated in animals (dogs, pigs, bovines and horses). Preliminary results suggested that MRVs are widespread in animals and that infections containing multiple serotypes, including MRVs of serotype 1 with an S1 gene similar to BatMRV1-IT2011, are common. This paper extends the current knowledge of MRVs and stresses the importance to continue and improve MRV surveillance in bats and other mammals through the development and standardization of specific diagnostic tools.

COBISS.SI-ID: 32291033
5.
Fatal human bocavirus infection in an 18-month-old child with chronic lung disease of prematurity

A fatal case of human bocavirus 1 pulmonary infection in an 18-month-old prematurely born child is described. Despite conventional and oscillatory ventilatory support, intractable hyperinflation developed with bilateral pneumothorax and acute cardiac failure 3 days after the onset of respiratory symptoms.

COBISS.SI-ID: 31526873