No abstract

Seventeen extended-spectrum ␤-lactamase (ESBL)-producing isolates of the family Enterobacteriaceae recovered from 1998 to 2000 in hospitals of five different cities in Poland were analyzed. They expressed several TEM-type ESBLs, TEM-4, TEM-29, TEM-85, TEM-86, TEM-93, and TEM-94. TEM-85 (L21F, R164S, E240K, T265M), TEM-86 (L21F, R164S, A237T, E240K, T265M), TEM-93 (M182T, G238S, E240K), and TEM-94 (L21F, E104K, M182T, G238S, T265M) were identified for the first time. Including the enzymes described earlier, TEM-47, TEM-48, TEM-49, and TEM-68, the group of known ESBLs of the TEM family produced by enterobacteria in Polish hospitals has increased to 10 variants. Comparative sequence analysis of the genes coding for all these ␤-lactamases revealed a view of their possible evolution, which, apart from the gradual acquisition of various mutations, could also have involved recombination events. Two different bla TEM-1 gene alleles were precursors of the ESBL genes: bla TEM-1A , which was the ancestor of bla TEM-93 , and bla TEM-1F , from which all the remaining genes originated. The evolution of the bla TEM-1F -related genes most probably consisted of three major separate lineages, one of which, including bla TEM-4 , bla TEM-47 , bla TEM-48 , bla TEM-49 , bla TEM-68 , and bla TEM-94 , was highly structured itself and could have been initiated by the bla TEM-25 gene, identified exclusively in France so far. Plasmid fingerprinting analysis revealed a high degree of diversity of plasmids carrying related bla TEM genes, which suggested either the intense diversification or transposition of bla TEM genes between different plasmids or some contribution of convergent evolution. The results of this study clearly demonstrate that the environment of Polish hospitals has been highly favorable for the rapid evolution of ESBLs.

The degree of seroprotection against diphtheria in Poland was evaluated by determination of IgG antibodies to Corymebacterium diphtheriae toxin (IgG-DTAb). The study population consisted of 4,829 healthy subjects aged from 1 day to 85 years from 7 regions of Poland. Serum samples collected between 1996 and 1998 were assayed for IgG-DTAb antibodies using a toxoid enzyme immunoassay. Neutralization of toxin in Vero cells was performed as a reference method with the WHO standard for human diphtheria antitoxin. The study revealed a lack of seroprotection (IgG-DTAb < 0.1 IU/ml) in 23% of individuals, basic seroprotection (0.1-1.0 IU/ml) in 64%, and effective seroprotection (> 1.0 IU/ml) in 13%. The non-protected group consisted of non-vaccinated children below 2 months of age (10%), individuals between 2 months and 18 years old (20%) and greater than 19 years old (70%). Of the adults, 32% were seronegative, 63% had basic seroprotection and only 5% were fully protected; 43% of adults between 30 and 64 years, who had not been vaccinated at least during the previous 10 years were not protected against diphtheria. The geometric mean titre (GMT) of IgG-DTAb was 0.25 IU/ml in the total population. Age-related GMTs differed significantly from each other and were higher (0.44 IU/ml) in individuals from 2 months to 18 years old, compared with 014 IU/ml and 0.17 lU/ml in children under 2 months and adults, respectively. No significant difference was found in the GMTs of men and women in all age groups. We conclude that the currently used vaccination programme in Poland is highly effective and assures protection against diphtheria in the majority of the population in the 10-year period following the last booster. However, a significant proportion of adults between 30 and 64 years lack protection and this indicates a need for booster immunization for this group.

COVID-19 was initially reported in China at the end of 2019 and soon thereafter, in March 2020, the WHO declared it a pandemic. Until October 2021, over 240 million COVID-19 cases were recorded, with 4.9 mln deaths. In order to stop the spread of this disease, it is crucial to monitor and detect any infected person. The etiologic agent of COVID-19 is a novel coronavirus called SARS-CoV-2. The gold standard for the detection of the virus is the RT-qPCR method. This study evaluated two RNA extraction methods and four commercial RT-qPCR assays routinely used in diagnostic laboratories for detecting SARS-CoV-2 in human specimens from the upper respiratory tract. We analyzed a panel of 70 clinical samples with varying RNA loads. Our study demonstrated the significant impact of the diagnostic methods selected by the laboratory on the SARS-CoV-2 detection in clinical specimens with low viral loads.

One of the tools to contain the SARS-CoV-2 pandemic was to increase the number of performed tests and to improve the access to diagnostics. To this effect, mobile collection sites (MCSs) were established. This study was performed on samples collected at the MCS between November 2020 and March 2021. We aimed to confirm/exclude SARS-CoV-2, differentiate SARS-CoV-2 variants, and detect other respiratory pathogens. SARS-CoV-2 and other respiratory viruses were identified by RT-qPCRs. A total of 876 (46.35%) SARS-CoV-2 positive specimens in the diagnostic tests were identified. The wild-type variant was determined in 667 (76.14%) samples; the remaining 209 (23.86%) samples specimens were identified as Alpha variant. A total of 51 (5.6%) non-SARS-CoV-2 cases were detected in retrospective studies. These accounted for 33 cases of mono-infection including rhinovirus (RV), human adenovirus (HAdV), human metapneumovirus (HMPV), enterovirus (EV), and influenza virus, and 18 cases of co-infection (SARS-CoV-2 with RV or HAdV or HMPV, and RV with EV). Our research shows that the results obtained from the MCS have value in epidemiological studies, reflecting national trends on a micro scale. Although the spread of COVID-19 is a major public health concern, SARS-CoV-2 is not the only pathogen responsible for respiratory infections.