Molecular epidemiology of human respiratory syncytial virus and human metapneumovirus in hospitalized children with acute respiratory infections in Croatia, 2014-2017

Acute respiratory infection (ARI) is the most common infection in children under 5 years of age and it is frequently caused by two pneumoviruses, human respiratory syncytial virus (HRSV) and human metapneumovirus (HMPV). Epidemic seasons of these viruses overlap and disease manifestations are highly similar, including severe lower ARI such as bronchiolitis or pneumonia. Reinfections with pneumoviruses are frequent and limited prevention treatment is available. Genetic diversity of HRSV and HMPV strains circulating in Croatia was monitored during four consecutive years (2014-2017). Co-circulation of multiple lineages was observed for both viruses. Within HRSV group A, ON1 strains gained strong predominance during the 4-year period, while previously dominant genotype NA1 was detected only sporadically. Similarly, newly occurring HMPV genotype A2c gained predominance over genotype A2b during this period, resulting in all infection in 2017 being caused by A2c. Along with phylogenetic analysis based on the commonly used fragments for detection and genotyping of these viruses, full length G and SH genes were also analysed. Evolutionary dynamics showed that inferred substitution rates of HRSV and HMPV are between 2.51 × 10^-3 and 3.61 × 10^-3 substitutions/site/year. This study established presence of recently described HMPV strains containing large duplications in the G gene in Croatia. Viruses with either of the two duplications belong to a subcluster A2c, which has completely replaced all other group A subclusters in 2017.

The impact of Corynebacterium glucuronolyticum on semen parameters: a prospective pre-post-treatment study

Corynebacterium glucuronolyticum (C. glucuronolyticum) is a rare isolate that is only recently being acknowledged as a potential urogenital pathogen. The bibliographical references on this bacterial species are scarce, and its influence on all semen parameters was hitherto unknown - therefore, the aim of this study was to evaluate its effects on a range of sperm quality parameters. A prospective approach to compare semen parameters before and after treatment was used in this study. C. glucuronolyticum in semen specimens was identified using analytical profile index biotyping system (API Coryne) and additionally confirmed by matrix-assisted laser desorption/ionization time-of-flight mass-spectrometry (MALDI-TOF MS), with the determination of antimicrobial susceptibility by Kirby-Bauer method. Semen analysis was performed according to the criteria from the World Health Organization (with the use of Tygerberg method of sperm morphology categorization). Very strict inclusion criteria for participants also included detailed medical history and urological evaluation. From a total of 2169 screened semen specimens, the inclusion rate for participants with C. glucuronolyticum that satisfied all the criteria was 1.01%. Antibiogram-guided treatment of the infection with ensuing microbiological clearance has shown that the resolution of the infection correlates with statistically significant improvement in the vitality of spermatozoa, but also with a lower number of neck and mid-piece defects. Parameters such as sperm count, motility and normal morphology were not affected. In addition, susceptibility testing revealed a trend towards ciprofloxacin resistance, which is something that should be considered when selecting an optimal treatment approach. Albeit it is rarely encountered as a monoisolate in significant quantities, C. glucuronolyticum may negatively influence certain sperm parameters; therefore, it has to be taken into account in the microbiological analysis of urogenital samples.

Prevalence and dynamics of cytomegalovirus infection among patients undergoing chronic hemodialysis

Cytomegalovirus (CMV) is an important pathogen in immunocompromised individuals. The aim of this study was to analyze prevalence and dynamics of CMV infection among patients undergoing chronic hemodialysis. From 2010 to 2012, a total of 162 patients and 160 control subjects were tested for the presence of CMV IgM and IgG antibodies using enzyme-linked immunosorbent assay. IgM/IgG reactive samples were further evaluated for IgG avidity to confirm or rule out recent primary CMV infection. The overall IgG seropositivity was higher in hemodialysis patients compared to controls (90.7% vs. 81.9%; crude odds ratio [OR] =2.02, 95% confidence interval [CI] =1.05–3.89; OR adjusted for age and gender = 2.18, 95% CI = 1.05–4.55). CMV IgG antibody titers were similar in both groups. There was no difference in CMV prevalence between males (87.9%) and females (96.3%). According to age, a progressive increase in seropositivity was observed in both hemodialysis patients and the control group. Three hemodialysis patients (1.9%) developed recurrent CMV infection (positive IgM with high avidity IgG antibodies). In one patient (2.9%), seroconversion was documented during the second year of the follow-up period indicating primary infection. In contrast, in the control group, recent primary CMV infection (positive IgM with low/borderline IgG avidity) was demonstrated in three subjects (1.9%), whereas one (0.6%) developed recurrent infection. On multivariate logistic regression, hemodialysis and older age were significant predictors for CMV seropositivity.

Outbreak of hand, foot and mouth disease caused by Coxsackie A16 virus in a childcare centre in Croatia, February to March 2011

We describe an outbreak of hand, foot and mouth disease (HFMD) in a childcare centre in a district of Zagreb county, north-west Croatia. A total of eleven cases of HFMD occurred in the childcare centre and another nine were reported from nearby areas in the district. Coxsackie A16 virus was diagnosed in 13 clinical specimens obtained from 11 symptomatic and asymptomatic children. All cases resolved without complications.

Outbreak of hand, foot and mouth disease caused by Coxsackie A16 virus in a childcare centre in Croatia, February to March 2011

We describe an outbreak of hand, foot and mouth disease (HFMD) in a childcare centre in a district of Zagreb county, north-west Croatia. A total of eleven cases of HFMD occurred in the childcare centre and another nine were reported from nearby areas in the district. Coxsackie A16 virus was diagnosed in 13 clinical specimens obtained from 11 symptomatic and asymptomatic children. All cases resolved without complications.

Transmission of the L-Zagreb mumps vaccine virus, Croatia, 2005-2008

We report on three cases of symptomatic transmission of the L-Zagreb mumps vaccine virus from three vaccinated children to five adult contacts. The five contact cases were parents of the vaccinated children and presented with parotitis and in one case also with aseptic meningitis. The etiology of the contacts' illness was determined by viral culture, genomic sequencing, serology and epidemiological linking. Two of the vaccinated children developed vaccine associated parotitis as an adverse event three weeks following immunization. Symptoms in contact cases developed five to seven weeks after the vaccination of the children. The five contact cases, as well as the three children with adverse events recovered completely. The children had been vaccinated with MMR vaccine produced by the Institute of Immunology Zagreb, each of them with a different lot. One of the possible explanations for these adverse events is that the very low levels of wild mumps virus circulation in the last decade, combined with waning immunity in those who received one dose of vaccine or suffered from mumps in childhood, resulted in susceptible young adults and that this unique epidemiological situation allows us to detect horizontal transmission of mumps vaccine virus.

Transmission of the L-Zagreb mumps vaccine virus, Croatia, 2005-2008

We report on three cases of symptomatic transmission of the L-Zagreb mumps vaccine virus from three vaccinated children to five adult contacts. The five contact cases were parents of the vaccinated children and presented with parotitis and in one case also with aseptic meningitis. The etiology of the contacts' illness was determined by viral culture, genomic sequencing, serology and epidemiological linking. Two of the vaccinated children developed vaccine associated parotitis as an adverse event three weeks following immunization. Symptoms in contact cases developed five to seven weeks after the vaccination of the children. The five contact cases, as well as the three children with adverse events recovered completely. The children had been vaccinated with MMR vaccine produced by the Institute of Immunology Zagreb, each of them with a different lot. One of the possible explanations for these adverse events is that the very low levels of wild mumps virus circulation in the last decade, combined with waning immunity in those who received one dose of vaccine or suffered from mumps in childhood, resulted in susceptible young adults and that this unique epidemiological situation allows us to detect horizontal transmission of mumps vaccine virus.

Norovirus genotypes involved in the outbreaks of gastroenteritis in Croatia during the winter season 2004--2005

Seven outbreaks and four sporadic cases of the non-bacterial gastroenteritis caused by a norovirus (NoV) were detected in Croatia between November 2004 and February 2005. An enzyme immunoassay (EIA) and three different RT-PCRs for the viral polymerase (ORF1 RT-PCR) and genogroup I (GI) or II (GII) of capsid gene regions (GI-ORF2 RT-PCR; GII-ORF2 RT-PCR) were performed to detect NoV in 21 stool samples. To characterize NoVs, sequencing of the ORF1 region was performed on 12 RT-PCR positive samples, whereas the ORF2 region was sequenced for 5 cases. Four outbreaks were caused by the genotype GII.4 (Lordsdale) and one outbreak was caused by the genotype GI.1 (Norwalk). One of the outbreaks was characterized as potentially mixed GII.4 and GI.1 infection. In the monitored period, genotype GII.4 dominated as the cause of noroviral infections in adults.

Immunity of the Croatian population to poliomyelitis--a serosurvey

Eight years after the last case of poliomyelitis it was of a special interest to determine the immunity level of the Croatian population to polio and thus to evaluate the possible risk of the revival of this infection. For this purpose, 200 sera samples were collected from individuals of different age and place of residence. Neutralizing antibodies (NT) for all three polioviruses were searched for. Antibody titers of > or = 1:8 were considered positive. Results of the study showed some 75% of the study subjects to have antibodies to polio type 1 and 2, and some 83% to type 3. Only 4% of the sera tested had no NT antibodies to any of the three types. The lowest mean geometric antibody titer (GMT) was for polio type 3 (GMT3 = 19.4; reciprocal value) and somewhat higher for type 1 (GMT1 = 23.5) and type 2 (GMT2 = 22.6). When the antibody titers were related with the age of the subjects, they were found not to decline with age, which was ascribed to periodical boosters with vaccinal strains. It is stressed that, in spite of the eradication of poliomyelitis achieved in Croatia, compulsory vaccination of the children should be continued until its global eradication.