Control of Acinetobacter baumannii outbreak in the neonatal intensive care unit in Latvia: whole-genome sequencing powered investigation and closure of the ward.

Background: Acinetobacter baumannii is an emerging pathogen capable of causing hospital-acquired infections (HAIs). It has the ability to survive on environmental surfaces for months, making transmission difficult to control. Our report describes the investigation and restriction of an outbreak of A.baumannii in the Neonatal Intensive Care Unit (NICU) using whole-genome sequencing (WGS) and multi-modal infection control measures. Methods: A prospective surveillance of HAIs was initiated in the NICU at the Pauls Stradins Clinical University Hospital (PSCUH) in Latvia on 1/9/2012 and identified an outbreak of A.baumannii. Case definitions for A.baumannii bloodstream infection (BSI) and colonization were implemented; surveillance cultures were obtained from all admitted patients to monitor the rate of colonization; an infection prevention and control team was formed and infection control interventions implemented. Environmental sampling of the NICU and Labour ward was performed. We employed WGS to differentiate phenotypically identical multidrug-resistant A.baumannii (MDRAB) strains from simultaneous intrahospital outbreaks in the adult Intensive Care Unit and NICU. Results: Between 1/9/2012 and 31/12/2017 the surveillance included 2157 neonates. A total of 17 neonates had A.baumannii BSI, with the highest rate of 30.0 cases per 1000 bed-days in November 2012. Rectal screening samples were positive for A.baumannii-complex in 182 neonates reaching 119.6 per 1000 bed-days in July 2015. All 298 environmental cultures were negative. Two phenotypically identical MDRAB isolates from the simultaneous intrahospital outbreaks were differentiated using WGS, ruling out an inter-ward transmission. Adherence to stringent infection control measures decreased BSI cases but colonization remained persistent. With several relapses, the outbreak was ongoing for four years. No new A.baumannii BSI cases were registered after total environmental decontamination in the NICU in July 2015. Colonization reappeared and persisted until in November 2016 when the ward was temporarily closed, relocated and renovated. No A.baumannii cases were registered after the renovation. Conclusion: The HAI surveillance system successfully detected and facilitated the control of the A.baumannii outbreak. Whole-genome sequencing was found to be a useful method for differentiation of phenotypically identical A.baumannii strains from the intrahospital outbreak. Only multi-modal infection control program, including closure, temporary relocation, and renovation of the ward, restricted the outbreak.

Association between CETP, MLXIPL, and TOMM40 polymorphisms and serum lipid levels in a Latvian population.

BACKGROUND: Abnormal lipid levels are considered one of the most significant risk factors for atherosclerosis and coronary artery disease, two of the main causes of death worldwide. Apart from monogenic cases of hypercholesterolemia, most of the common dyslipidemias are caused by a number of low-impact polymorphisms. It has recently been reported that frequent polymorphisms at a large number of loci are significantly associated with one or more blood lipid parameters in many populations. Identifying these associations in different populations and estimating the possible interactions between genetic models are necessary to explain the underlying genetic architecture of the associated loci and their ultimate impact on lipid-associated traits. METHODS: We estimated the association between 144 common single-nucleotide polymorphisms (SNPs) from published genome-wide association studies and the levels of total cholesterol, low- and high-density lipoprotein-cholesterol, and triglycerides in 1273 individuals from the Genome Database of the Latvian Population. We analyzed a panel of 144 common SNPs with Illumina GoldenGate Genotyping Assays on the Illumina BeadXpress System. RESULTS: Ten SNPs at the CETP locus and two at the MLXIPL locus were associated with reduced high-density lipoprotein-cholesterol levels; one SNP at the TOMM40 locus was associated with increased low-density lipoprotein-cholesterol; and four SNPs at the MLXIPL locus were associated with increased log triglyceride levels. There was also a significant correlation between the number of risk alleles and all the lipid parameters, suggesting that the coexistence of many low-impact SNPs has a greater effect on the dyslipidemia phenotype than the individual effects of found SNPs. CONCLUSION: We conclude that the CETP, MLXIPL, and TOMM40 loci are the strongest genetic factors underlying the variability in lipid traits in our population.