Acute ischemic events after COVID-19 infection in patients undergoing maintenance hemodialysis.

INTRODUCTION: Patients undergoing maintenance hemodialysis have unique risk factors that render them prone to ischemia. To what extent coronavirus infectious disease 2019 (COVID-19) increases this risk is unknown. METHODS: This retrospective cohort study included incident patients undergoing maintenance hemodialysis from one city in Turkey. A comparison was made between those who developed COVID-19 and those who did not for clinical variables. Independent predictors of acute ischemic complications in the total cohort were assessed using the logistic regression analysis. FINDINGS: By the start of the pandemic in Turkey, 33 of 154 (21.4%) patients developed COVID-19. During the 15 months of median follow-up after the start of the pandemic, 16 (10.4%) patients developed acute ischemic complications. These included acute myocardial infarction (n = 10), acute ischemic stroke (n = 4), acute peripheral artery thrombosis (n = 1), and pulmonary thromboembolism (n = 1). Overall, acute ischemic events occurred more commonly in those who experienced COVID-19 (24.2% vs. 6.6%, p = 0.007). Ischemia-free survival was significantly shorter in the COVID-19 group (p = 0.001). In the eight patients with COVID-19, ischemic complications emerged at a median 185 (range 21-306) days after the diagnosis of COVID-19. While age, dialysis vintage, and experience of COVID-19 were found as factors significantly associated with the development of acute ischemic events in univariate analysis, the association between COVID-19 and acute ischemia remained significant in the multivariate regression model (odds ratio 3.99, 95% CI [1.3, 12.13], p = 0.016). During the pandemic, 23 (14.9%) patients died. Overall survival was significantly shorter among those who developed acute ischemic event (p < 0.001). The hazard ratio of acute ischemic event for death was 6.76 (95% CI [2.92, 15.66], p < 0.001). DISCUSSION: A considerable number of patients undergoing maintenance hemodialysis developed acute ischemic complications weeks to months after the resolution of COVID-19. Hemodialysis patients appear to require specific interventions in order to prevent subsequent acute ischemic events after the resolution of COVID-19.

Molecular identification of adenoviral conjunctivitis in Turkey.

PURPOSE: The aim of the study was isolation of adenoviruses by cell culture and identification using polymerase chain reaction (PCR) and phylogenetic analyses in patients clinically diagnosed with viral conjunctivitis in Ankara, Turkey. METHODS: Conjunctival swabs from 34 patients with acute conjunctivitis were tested using cell culture isolation and PCR for adenovirus detection. PCR-positive samples were sequenced and typed. RESULTS: The positive results of adenovirus were 26.5% (9 of 34) by the PCR method and 20.6% by culture isolation. Nine samples positive at PCR were identified by phylogenetic analyses as human adenovirus 8 (HAdV-8) (4 of 9), HAdV-3 (3 of 9), HAdV-4 (1 of 9), and HAdV-B (1 of 9). CONCLUSIONS: Our study showed types of adenoviruses in patients with ocular infection that occurred in this region of Turkey for the first time. Furthermore, sequence-based typing method is an efficient, accurate, and rapid means of diagnosis and typing of the adenovirus and has significant clinical and epidemiologic implications. HAdV-8 was major type for acute conjunctivitis in Ankara, Turkey. Further studies are required to reveal the major types of HAdVs that cause ocular diseases in this region of the world.

[Evaluation of laboratory diagnosis of the first norovirus outbreak in Turkey in 2008]. / Türkiye'de 2008 yilinda ortaya çikan ilk norovirus salgininin laboratuvar sonuçlarinin degerlendirilmesi.

Norovirus (NoV) is one of the most prominent agents of gastroenteritis and water/food-borne outbreaks affecting all of the age groups in the world. As the identification of the etiologic agent is important during gastroenteritis outbreaks, it is recommended to combine two different methods for rapid and reliable laboratory diagnosis of NoV. Although NoV outbreaks have been observed in many different countries of the world, there was no report on "NoV outbreak" in Turkey till 2008 due to the absence of a regular surveillance system for non-bacterial gastroenteritis. This study aimed to present the laboratory results for "the first NoV outbreak" in Turkey in 2008. A number of cases with diarrhea and nausea/vomiting initially emerged in Aksaray (located at the southern part of central Anatolia) in May 2008, followed by cases from Sereflikochisar, Kirsehir, and Adana provinces (located at central and southern Anatolia; geographically closer regions). However, regional laboratories declared that no known bacterial (Salmonella spp., Shigella spp., enterotoxigenic Escherichia coli), viral (Rotavirus, Adenovirus) and parasitic agents were detected. A total of 50 stool samples were sent to the Virology Reference Laboratory (Refik Saydam Hygiene Center, Ankara) for further investigations including NoV. For the investigation of NoV, the samples were analysed by using antigen-ELISA (Ridascreen, R-Biopharm, Germany) and real-time polymerase chain reaction(PCR) (Roche Diagnostics GmbH, Germany) methods. Of the samples, 26% (13/50) were found antigen positive, whereas 33% (13/40) were positive for viral nucleic acids. The positivity rates determined by ELISA and PCR were as follows, respectively; 57% (4/7) and 71% (5/7) in Aksaray, 25% (1/4) and 25% (1/4) in Sereflikochisar, 28% (7/25) and 40% (6/15) in Kirsehir, 7% (1/14) and 7% (1/14) in Adana. Nine (69.2%), and 4 (30.8%) out of 13 positive samples were genotyped as NoV GI and GII, respectively. The sensitivity and specificity of antigen-ELISA method were found as 61.5% and 100%, respectively, when compared with real-time PCR. In conclusion, further epidemiological studies and genomic analysis are needed for the detection and control of circulating strains in Turkey, since NoV outbreaks spread rapidly and cause serious economical and workforce loss.

[Investigation of herpes simplex virus in viral meningoencephalitis suspected cases using molecular and serological methods]. / Viral meningoensefalit süpheli hastalarda herpes simpleks virusunun moleküler ve serolojik yöntemlerle arastirilmasi.

Herpes simplex virus (HSV) meningoencephalitis has a high mortality rate if proper antiviral therapy is not applied. Thus rapid diagnosis is of peculiar importance in such cases. In this study we aimed to evaluate the use of polymerase chain reaction (PCR) and detection of intrathecally synthesized antibodies by serological methods in viral meningoencephalitis suspected cases to determine HSV as the causative agent. Seventeen cases with cerebrospinal fluid (CSF) samples with microscopical and biochemical findings compatible with viral encephalitis were included in this study. CSF samples yielded no bacterial growth. Cell cultures propagated in Vero cell line and PCR with different primer sets against HSV-1 and HSV-2 (specific for US7 and US2 gene regions, respectively) were used to investigate the presence of HSV in CSF. Serum samples were taken simultaneously with the CSF sampling and "Reibergram" graphics and antibody index (AI) calculations were used for the evaluation of intrathecal antibody synthesis. Albumin and total IgG levels in serum and CSF samples measured with nephelometry (Dade-Behring, Germany) for Reibergram graphics, albumin and IgG ratios were calculated. Quantitative levels of HSV 1+2 IgG were measured in serum and CSF samples using ELISA (HSV-1/2 Pool; Antibody Determination in CSF, Euroimmun, Germany) for AI determination. One of the CSF samples obtained one week after the neurological symptoms had started, yielded HSV-2 in cell culture and also HSV-2 DNA was detected by PCR. Intrathecal antibody synthesis was not detected in this case. In two cases with symptoms lasting for more than three weeks, intrathecal IgG synthesis in Reibergrams and pathological intrathecal HSV AI (27.9 and 7.9, respectively) were detected, however, virus isolation and PCR detection were not successful. For the other 14 cases, HSV-DNA were found negative and no intrathecal antibody synthesis were detected. HSV meningoencephalitis can be diagnosed via using PCR which has been accepted as gold standard in recent years, with 24 hours turn-around time. However, if CSF samples were taken later than the first week following the beginning of symptoms, possibility of HSV detection by PCR is lowered. According to the data obtained from this limited study, it may be suggested that PCR may be used for the detection of HSV-DNA in CSF samples during the early phase of meningoencephalitis cases, however, consideration must be taken to detect the intrathecal antibodies during the later phases of the infection where intrathecal antibody synthesis starts.

Herpes simplex type-2 encephalitis masked by diabetic ketoacidosis.

Diabetic ketoacidosis is a life-threatening acute complication of type-1 diabetes mellitus. Infection is the most common precipitating factor for diabetic ketoacidosis and is responsible for more than 50% of the cases. Here, we present a case study of a young man with herpes simplex virus type-2 encephalitis masked by diabetic ketoacidosis. We aim to orient clinicians towards being vigilant against such clinical scenarios.

[Serotype distribution of enteroviruses isolated from paediatric cases prediagnosed as aseptic meningitis between 2001-2004 period]. / 2001-2004 yillari arasinda aseptik menenjit ontanili pediatrik olgulardan izole edilen enterovirus serotiplerinin dagilimi.

Enteroviruses have major clinical and public health importance and are one of the leading causes of aseptic meningitis. There are many diseases with similar clinical symptoms and cerebrospinal fluid (CSF) findings of aseptic meningitis, thus virus isolation and identification is crucial for definitive diagnosis. Virological diagnosis is nonetheless important to distinguish between induced meningitis and other treatable causes of disease with a similar clinical picture. A total of 249 samples obtained from 246 cases (age range: 0-15 years), prediagnosed as aseptic meningitis, were sent to Virology Laboratory of Refik Saydam Hygiene Center. The patients were followed at Department of Pediatric Infectious Diseases in the Social Security Hospital, Ankara, Turkey, between 2001 and 2004. Stool (n: 180), CSF (n: 54) and throat swab (n: 15) samples have been inoculated to RD (rhabdomyosarcoma), Hep-2 (human epithelioma) and L20B (transgenic mice) cell lines, and followed up for the presence of cytopathic effects. A total of 95 enterovirus strains were isolated from 85 (34.6%) cases, and serotyped by using RIVM (National Institute of Public and the Environment, Nederlands) antisera with microneutralization method. As a result, the most frequently isolated types were found as echovirus type 30 (n: 24) and coxsackievirus type B (n: 19), which were most frequently isolated between July to October. This is the first report from Turkey for aseptic meningitis cases due to echovirus type 25 (n:3), 18 (n:2), 14 (n:1), 13 (n:4), 11 (n:6), 9 (n:1), 6 (n:9), 5 (n:1), 4 (n:1) and coxsackievirus type A9 (n:1).

Laboratory diagnosis of enteroviral infections of the central nervous system by using a nested RT-polymerase chain reaction (PCR) assay.

Enteroviruses are the most common pathogens identified in infants hospitalized for suspected aseptic meningitis. Rapid detection of enterovirus infection is essential in taking the decision for treatment with antiviral agents and applying infection control measures in hospitalized pediatric patients. The purpose of this study was to compare the results of conventional virus isolation with those of enteroviral RNA detection by reverse transcription (RT)-PCR method in identical specimens from cases of suspected aseptic meningitis. Cerebrospinal fluid (CSF) samples were collected for viral examination from 68 pediatric patients with suspected aseptic meningitis from 1999 to 2002. These samples were inoculated in HeLa, Hep-2 and RD cell culture. The viral RNA was investigated by in-house RT-PCR method. The isolated viruses were typed by neutralization test. 36 of the 68 specimens were detected to be enterovirus positive by culture method, while 43 of them yielded positive results when RT-PCR method is used. Discrepancies occurred between the two methods in 15 specimens. While 11 specimens were positive by RT-PCR, these are found to be culture-negative. The isolated viruses were typed as Echovirus 30 (n: 30), Group B coxsackievirus (n: 5) and one isolate could not be typed by neutralization. Because of higher sensitivity and rapidity of RT-PCR, it is superior (p = 0.016) to virus culture of CSF for the diagnosis of enterovirus meningitis. Although the clinical usefulness of viral culture from CSF is limited, the final laboratory identification needs cultural techniques.

A hospital outbreak of aseptic meningitis due to echovirus type 30 in Antalya, Turkey.

We analyzed clinical and laboratory findings of 23 hospitalized patients with aseptic meningitis in the Department of Pediatrics, Akdeniz University Hospital. The patients presented with the classic symptoms and signs of aseptic meningitis. Protein levels of the cerebrospinal fluid (CSF) samples ranged from 18 to 99 mg/dl, with a mean of 36.5 +/- 4.9 mg/dl. The mean ratio of CSF glucose compared to blood samples was 0.73. Echovirus type 30 was identified in CSF and/or stool samples of 19 patients. Four patients had negative virus culture. The outcome was favorable in all patients. We thought that this outbreak of aseptic meningitis in our department might denote a summer outbreak in the city. However, this remained unproven since field investigations could not be completed. Advances in virus culture or polymerase chain reaction techniques and satisfactory medical records may help patient care by promoting early diagnosis and by eliminating unnecessary antibiotic therapy, allowing epidemiological studies.

[Evaluation of an ELISA kit made in our laboratory for intratypic discrimination of poliovirus type 1 strains isolated from acute flask paralysis]. / Akut flask paralizli olgulardan izole edilen poliovirus tip-1 suslarinin intratipik ayiriminda laboratuvar yapimi bir ELISA kitinin degerlendirilmesi.

In this study, we aimed to develop and evaluate an enzyme based immunological method (ELISA) for the intratypic differentiation (whether if Sabin like-SL, or non Sabin like/wild type-NSL) of poliovirus type 1 isolates, in the frame of Polio Eradication Programme (PEP) in Turkey. Five poliovirus type 1 strains which were formerly isolated and identified in our laboratory from fecal samples of acute flask paralysis (AFP) patients, and standard reference strains of vaccine type 1 and prototype wild (Mahoney) polioviruses have been tested into plate wells that bounded with 5 different monoclonal antibodies (mAbs B18, S2-36, M18, B82, M49). The wells which gave high absorbance than cutoff value estimated by comparing negative control wells, were accepted as positive. As a result, the standard poliovirus strains were differentiated correctly, whereas 2 patient isolates were identified as SL and 3 were NSL. In conclusion, our home-made ELISA method found to be successful for intratypic differentiation of poliovirus type 1 isolates, however more detailed studies are necessary in order to increase the susceptibility and specificity of this test.

[Sensitivities of various cell cultures for the isolation of enteroviruses]. / Enteroviruslarin izolasyonunda degisik hücre kültürlerinin duyarliliklari.

In the present study, the sensitivities of HEp-2 (human epithelioma), RD (rhabdomyosarcoma) and L20B (mouse cells, that have receptors for human polioviruses) cell cultures have been evaluated and compared, for the isolation and identification of enteroviruses from the stool and cerebrospinal fluid samples of patients with acute flask paralysis and aseptic meningitis, which were examined between the years 1999-2000, in Refik Saydam Institute of Hygiene Center, Virology, Tissue Culture and Enterovirus Laboratory. Of a total of 1663 samples, 131 viral strains were isolated, and 120 of them were identified as enteroviruses, and 11 as adenoviruses. The isolation rates of 48 Sabin-like polioviruses from HEp-2, RD and L20B cell lines were found similar, as 83.3%, 87.5% and 91.6%, respectively. All of 47 Echovirus strains were isolated from RD cells, all of 13 Coxsackie type B strains were isolated from HEp-2 cells, and all of 12 non-polio enteroviruses were isolated from RD cells. All of 11 adenovirus strains that have been grown in Hep-2 cells, were thought to be occasionally isolated due to the passage of viruses to gastrointestinal tract, and excreted via stool, thus having no clinical significance for these patients. As a result, it was concluded that, all of these three cell lines and especially L20B were sensitive for polioviruses, RD cell line being more sensitive for Echovirus, and HEp-2 cell line being more sensitive for Coxsackie type B virus strains.

[Standardization of neutralization tests using the COBL cell line and comparison with the particle agglutination test for measles serology]. / Kizamik serolojisinde nötralizasyon testinin COBL Hücresi kullanilarak standardizasyonu ve partikül aglütinasyon testi ile karsilastirilmasi.

The aim of the present study was the detection and comparison of measles antibody titers with particle agglutination (PA) and neutralization (Nt) methods, in the sera samples of 364 subjects from different age groups. PA method was performed with a commercial test kit (Serodiameasles, Fujirebio Com. Japan), and Nt test which was standardized in this study, by using COBL (cord blood) cell lines, has been started to use in our laboratory as a reference method. As a result, antibody titers detected by PA were in parallel to the titers which detected by Nt test, and it was concluded that the differences in antibody titers would arise from the differences of test principles and viral antigens.

Characterization of a sandfly fever Sicilian virus isolated during a sandfly fever epidemic in Turkey.

BACKGROUND: Phleboviruses cause sandfly fever but isolates are rare. OBJECTIVES: To analyse samples from concurrent outbreaks of suspected sandfly fever in the Mediterranean provinces of Adana, Izmir and the central province of Ankara, Turkey. STUDY DESIGN: Samples from acute cases were analysed by immunofluorescence assay (IFA). Virus isolation was attempted and pyrosequencing performed. RESULTS: In IFA 38% of 106 samples tested scored IgM positive for sandfly fever Sicillian virus (SFSV), 12% for SFSV/sandfly fever Cyprus Virus (SFCV) and only 4% for SFCV. A sandfly fever Sicilian type virus designated sandfly fever Turkey virus (SFTV) was isolated. The S-segment sequence of SFTV had a homology of 98% to that of SFCV. The M-segment sequence showed a 91.1% homology to the only SFSV sequence available. The L-segment sequence showed a homology of 58% and 60.3% to Toscana virus and Rift Valley Fever virus sequences, a partial 201nt sequence showed 95.5% homology to the SFSV Sabin strain. CONCLUSION: A new phlebovirus related to sandfly fever Sicilian virus, SFTV was isolated and characterized from acute patient material. The sandfly fever Sicilian virus activity seems to be changing in Turkey. Entomological studies are needed.

Molecular epidemiology of Crimean-Congo hemorrhagic fever virus in Turkey: occurrence of local topotype.

The goal of this study was to investigate the molecular epidemiology of Crimean-Congo hemorrhagic fever virus (CCHFV) in Turkey. The study was performed on a total of 48 confirmed human CCHF cases from 2006 to 2008. The majority of the CCHF viral strains in Turkey were found to belong to the European lineage. Local CCHF viral strains are grouped into two main clusters, which can be further divided into two sub-groups. We also identified an AP92-like virus causing clinical disease in Corum (a mid-Anatolian province). Phylogenetic analysis revealed that the most recent CCHFV infections were caused by intrinsic (or native) CCHF viral strains, which we identified as the local topotype. Comparison of deduced amino acid sequences of S-segment RNAs indicated that the local topotype was derived from viruses of previous years, most likely by a low rate recombination. No genetic differences, based on S- and M-segment RNA sequences, were found between human and tick viral isolates. This data suggest that replication of CCHFV in the tick vector, whether Rhiphicephalus spp. or Hyalomma spp., has no effect on the viral genomic structure.

Phylogenetic analysis of wild-type 1 polioviruses isolated during the final period of transmission in Turkey.

The last poliomyelitis case associated with a wild poliovirus in Turkey occurred in November 1998. This was the last known case of paralytic poliomyelitis caused by indigenous wild poliovirus in the World Health Organization's European Region. This study investigated the genetic relationships of wild-type 1 polioviruses at the latest period of transmission. A phylogenetic tree was constructed on the basis of the VP1/2A sequence from 14 wild-type 1 polioviruses isolated from Turkey in 1994-1998, along with those from other areas of the world. The Turkey isolates in the latest period of transmission were closely related to each other, forming a cluster distinct from other strains. The results showed that these viruses had been spreading indigenously in the eastern and south-eastern parts of Turkey, and ceased transmission there during 1998. This finding serves as a reference for future poliovirus surveillance both in Turkey and worldwide.