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Objective: Stenotrophomonas maltophilia is an emerging multi-drug resistant, opportunistic pathogen in the neonatal intensive care unit (NICU). In this study, we aimed to assess the incidence, clinical features, antibiotic susceptibility, and treatment options of S. maltophilia infection among the healthcare-associated infections (HAIs) in the neonatal unit. Methods: In this study, the patients who were hospitalized in the NICU between January 2020 and December 2021 with S. maltophilia isolated from clinical samples were included. Demographic, clinic features, and microbiological findings of the patients were retrospectively evaluated by using the medical records. The samples (lower respiratory tract, urine, peritoneal fluid) were first examined microscopically by gram preparation and cultured. Antibiotic susceptibility tests were performed according to the recommendations of The European Committee on Antimicrobial Susceptibility Testing (EUCAST) for TMP-SMX. Results: S. maltophilia was isolated in 38 clinical samples of the 20 patients who were hospitalized at the NICU between January 2020 and December 2021. A total of 40 % (n = 8) of samples from different patients were accepted as colonization. Ventilator-associated pneumonia was determined in 55 % (n = 11), and urinary tract infection in 5 % (n = 1). S. maltophilia-associated bacteremia was not detected in any of the cases. The TMP-SMX susceptibilities of the strains were as it follows: 3 (15 %) were resistant (R), 7 (28 %) were susceptible (S), and 10 (47 %) were susceptible-increased exposure (I). Three of these patients were given dual antibiotics therapy (levofloxacin plus TMP-SMX) and nine of them were given only TMP-SMX. The most common hospital-acquired infectious agents are Gram negative microorganisms (51 %), followed by coagulase negative staphylococci (CNS), Staphylococcus aureus (24 %) and S. maltophilia (24 %). Conclusion: Increasing TMP-SMX resistance and specific drug and dosage-related problems in the neonatal unit are important problems in treatment management.

Abstract Background Antibiotic-associated diarrhea is one of the most frequent side effects of antimicrobial therapy. We assessed the epidemiological data of antibiotic-associated diarrhea in pediatric patients in our region. Methods The prospective multi-center study included pediatric patients who were initiated an oral antibiotic course in outpatient clinics and followed in a well-established surveillance system. This follow-up system constituded inclusion of patient by the primary physician, supply of family follow-up charts to the family, passing the demographics and clinical information of patient to the Primary Investigator Centre, and a close telephone follow-up of patients for a period of eight weeks by the Primary Investigator Centre. Results A result of 758 cases were recruited in the analysis which had a frequency of 10.4% antibiotic-associated diarrhea. Among the cases treated with amoxicillin-clavulanate 10.4%, and cephalosporins 14.4% presented with antibiotic-associated diarrhea. In the analysis of antibiotic-associated diarrhea occurrence according to different geographical regions of Turkey, antibiotic-associated diarrhea episodes differed significantly (p = 0.014), particularly higher in The Eastern Anatolia and Southeastern Anatolia. Though most commonly encountered with cephalosporin use, antibiotic-associated diarrhea is not a frequent side effect. Conclusion This study on pediatric antibiotic-associated diarrhea displayed epidemiological data and the differences geographically in our region.

Objective: Respiratory viruses are an important cause of morbidity and mortality in pediatric hematology oncology patients. We aimed to determine the infection rate, clinical and epidemiological characteristics of respiratory viruses in pediatric patients with hemato-oncological malignancy, aplastic anemia and congenital neutropenia and to show how these viruses affect the primary disease course and treatment. Methodology: Between August 2015 and December 2018, 97 patients aged between 5 months and 215 months who were admitted to Istanbul University, Istanbul Faculty of Medicine, Department of Pediatric Haematology-Oncology with acute respiratory tract infection findings and diagnosed with Haemato-Oncological Malignancy, Congenital Neutropenia, Aplastic Anaemia and who had viral respiratory panel were retrospectively analysed. In the viral respiratory panel test, nasal swab samples of the patients were evaluated by RT-multiplex PCR method. SPSS (Statistical Package for the Social Sciences) 22.0 programme was used for statistical analyses Results: A total of 97 patients, 52 males (53.6%) and 45 females (46.4%), aged between 5 months and 215 months (78.81±60.17 months, median 60 months) were included in the study. The most common viral respiratoty panel (VRP) positivity was observed between 5 months and 208 months and the mean age was 85.49±61.73 months (median=81 months). Although 44.3% (n=43) of the patients presented in winter and 23.7% (n=23) in autumn, VRP positivity was more common in patients presenting in spring (n=43, 70%) and winter (n=22, 51.2%) seasons. When the VRP results of the patients were analysed; 50.5% (n=49) were positive; 39.2% (n=38) were monoinfection, 11.3% (n=11) were co-infection) and 49.5% (n=48) were negative. When we looked at the VRP results, rhinovirus (hRV) was the most common virus with a frequency of 22.4% (n=11). Other viruses were Respiratory Synsititial Virus (RSV) A/B (14.2% n=7), Parainfluenza (14.2% n=7), Influenza (8.2% n=4), Coronavirus (8.2% n=4), Metapneumovirus (2.1% n=1), Mycoplasma pneumonia (6.1% n=3). Among the co-infections seen in a total of 11 patients, hRV and RSV A/B were the most common viruses accompanying other viruses with a rate of 63.6% (n=7). Among a total of 67 patients who were in various stages of CT and whose treatment was completed, the most common VRP positivity was seen in patients in the induction phase with a rate of 28.3% (n=19). Of the 12 patients with co-infection, 5 (41.6%) were in the induction phase. Cough (n=59 60.8%) and fever (n=47 48.5%) were the most common presenting complaints, accompanied by wheezing (n=17 17 17.5%), respiratory distress (n=11 11.3%), diarrhoea/vomiting (n=9 9.3%) and muscle pain (n=9 9.3%). VRP was positive in 43.9% of patients presenting with fever. The most common hRV virus was found most frequently in spring and winter seasons. Viral respiratory infection positivity was most frequently seen in ALL (n=16 33.3%), second most frequently in Hodgkin's Lymphoma (n=5 10.5%) and Neuroblastoma (n=5 10.5%). Among the patients, upper respiratory tract infection (URTI) (74.2%, n=72) was more common than lower respiratory tract infection (LRTI) (25.8%, n=25). The rate of LRTI in co-infections (28.0%, n=14) was higher than the rate of URTI (6.9%, n=5) and was statistically significant (p=0.021). When hemogram and biochemistry results were analysed, although neutropenia (50.5%) and lymphopenia (50.5%) were observed at a high rate in patients with positive VRI, they were not statistically significant when compared with VRP positivity. Of the patients with VRP positivity (50.5% n=49), 34.6% (n=17) required hospitalisation due to viral respiratory infection. Of the patients included in the study, 4 patients need intensive care unit due to bacterial pneumonia (Mycoplasma pneumonia and Pneumocystis jireovici), bleeding into a mass (hepatoblastoma) and pericardial effusion (peripheric T cell lymphoma). In 7 patients whose chemotherapy duration was prolonged, the duration of treatment prolongation ranged between 4 and 60 days (mean 19.29±20.69 and median 10 days). No VRI-related mortality was observed among the patients during the follow-up period. Conclusion: Identification of respiratory viruses in pediatric hematology oncology patients contributes to the management of their primary disease.

Case report: The 22-month-old male and 15-day-old female patients presented with persistent stridor since birth. Tracheoscopy of the first patient revealed a 90% obstructing hemangioma in the subglottic area, while the second patient's CT scan showed a hemangioma at the subglottic level. Both patients were initiated on propranolol therapy. These cases highlight the significance of subglottic hemangioma as a treatable cause of stridor in infants and emphasize the importance of propranolol treatment.

Background: Understanding SARS-CoV-2 seroprevalence among health care personnel is important to explore risk factors for transmission, develop elimination strategies and form a view on the necessity and frequency of surveillance in the future. Methods: We enrolled 4927 health care personnel working in pediatric units at 32 hospitals from 7 different regions of Turkey in a study to determine SARS Co-V-2 seroprevalence after the first peak of the COVID-19 pandemic. A point of care serologic lateral flow rapid test kit for immunoglobulin (Ig)M/IgG was used. Seroprevalence and its association with demographic characteristics and possible risk factors were analyzed. Results: SARS-CoV-2 seropositivity prevalence in health care personnel tested was 6.1%. Seropositivity was more common among those who did not universally wear protective masks (10.6% vs 6.1%). Having a COVID-19-positive co-worker increased the likelihood of infection. The least and the most experienced personnel were more likely to be infected. Most of the seropositive health care personnel (68.0%) did not suspect that they had previously had COVID-19. Conclusions: Health surveillance for health care personnel involving routine point-of-care nucleic acid testing and monitoring personal protective equipment adherence are suggested as important strategies to protect health care personnel from COVID-19 and reduce nosocomial SARS-CoV-2 transmission.

Introduction Health care workers (HCWs) are disproportionately exposed to infectious diseases and play a role in nosocomial transmission, making them a key demographic for vaccination. HCW vaccination rates are not optimal in many countries; hence, compulsory vaccination policies have been implemented in some countries. Although these policies are effective and necessary under certain conditions, resolving HCWs’ hesitancies and misconceptions about vaccines is crucial. HCWs have the advantage of direct contact with patients; hence, they can respond to safety concerns, explain the benefits of vaccination, and counter antivaccine campaigns that escalate during pandemics, as has been observed with COVID-19. Method A short survey was carried out in May–June 2020 on the vaccination status of HCWs working with pediatric patients with COVID-19. The survey inquired about their vaccination status (mumps/measles/rubella [MMR], varicella, influenza, and diphtheria/tetanus [dT]) and willingness to receive hypothetical future COVID-19 vaccines. The respondents were grouped according to gender, age, occupation, and region. Results In total, 4927 HCWs responded to the survey. Most were young, healthy adults. The overall vaccination rates were 57.8% for dT in the past 10 years, 44.5% for MMR, 33.2% for varicella, and 13.5% for influenza. Vaccination rates were the highest among physicians. The majority of HCWs (81%) stated that they would be willing to receive COVID-19 vaccines. Conclusion Although vaccination rates for well-established vaccines were low, a majority of HCWs were willing to receive COVID-19 vaccines when available. Education and administrative trust should be enhanced to increase vaccination rates among HCWs.

Abstract The frequency of bacterial factors causing central nervous system infections has decreased as a result of the development of our national immunization program. In this study, it is aimed to obtain the data of our local surveillance by defining the viral etiology in cases diagnosed with meningoencephalitis for 1 year. Previously healhty 186 children, who applied with findings suggesting viral meningoencephalitis to 8 different tertiary health centers between August 2018 and August 2019, in Istanbul, were included. The cerebrospinal fluid (CSF) sample was evaluated by polymerase chain reaction. The M:F ratio was 1.24 in the patient group, whose age ranged from 1 to 216 months (mean 40.2 ± 48.7). Viral factor was detected in 26.8%. Enterovirus was the most common agent (24%) and followed by Adenovirus (22%) and HHV type 6 (22%). In the rest of the samples revealed HHV type 7 (10%), EBV (6%), CMV (6%), HSV type 1 (6%), Parvovirus (4%) and VZV (2%). The most common symptoms were fever (79%) and convulsions (45.7%). Antibiotherapy and antiviral therapy was started 48.6% and 4% respectively. Mortality and sequela rate resulted 0.53% and 3.7%, respectively. This highlights the importance of monitoring trends in encephalitis in Turkey with aview to improving pathogen diagnosis for encephalitis and rapidly identifying novel emerging encephalitis-causing pathogens that demand public health action especially in national immunisation programme.

Diabetic patients may experience more severe Staphylococcus aureus-related respiratory tract infections such as necrotizing pneumonia (NP). A 13-year-old girl with uncontrolled diabetes mellitus was admitted to pediatric intensive care unit (PICU) with diabetic ketoacidosis and respiratory distress. Her initial evaluation revealed diffuse pneumonic infiltration that progressed to NP within days. She was intubated and placed on mechanical ventilator (MV) support. Positive inotropes and broad-spectrum antibiotics were initiated. Methicillinresistant S. aureus was isolated from blood and pleural specimen cultures. In spite of aggressive medical treatment, infection could not be controlled and lobectomy was performed. However, the patient was fistulized and right total pneumonectomy was performed on the 16th and 29th days of PICU admission. She gradually got better and was weaned from MV. On the 59th day, she was discharged oxygen-free from the hospital. Early surgical intervention should be considered for the treatment of NP resistant to medical therapy.

Objectives: The aim of this study is to identify the epidemiological, clinical, and laboratory features of coronavirus disease 2019 (COVID-19) in children.Methods: A retrospective study was conducted by pediatric infectious disease specialists from 32 different hospitals from all over Turkey by case record forms. Pediatric cases who were diagnosed as COVID-19 between March 16, 2020, and June 15, 2020 were included. Case characteristics including age, sex, dates of disease onset and diagnosis, family, and contact information were recorded. Clinical data, including the duration and severity of symptoms, were also collected. Laboratory parameters like biochemical tests and complete blood count, chest X-ray, and chest computed tomography (CT) were determined.Results: There were 1,156 confirmed pediatric COVID-19 cases. In total, male cases constituted 50.3% (n = 582) and females constituted 49.7% (n = 574). The median age of the confirmed cases was 10.75 years (4.5–14.6). Of the total cases, 90 were younger than 1 year of age (7.8%), 108 were 1–3 years of age (9.3%), 148 were 3–6 years of age (12.8%), 298 were 6–12 years of age (25.8%), 233 were 12–15 years of age (20.2%), and 268 cases were older than 15 years of age (23.2%). The most common symptom of the patients at the first visit was fever (50.4%) (n = 583) for a median of 2 days (IQR: 1–3 days). Fever was median at 38.4°C (38.0–38.7°C). The second most common symptom was cough (n = 543, 46.9%). The other common symptoms were sore throat (n = 143, 12.4%), myalgia (n = 141, 12.2%), dyspnea (n = 118, 10.2%), diarrhea (n = 112, 9.7%), stomachache (n = 71, 6.1%), and nasal discharge (n = 63, 5.4%). When patients were classified according to disease severity, 263 (22.7%) patients were asymptomatic, 668 (57.7%) patients had mild disease, 209 (18.1%) had moderate disease, and 16 (1.5%) cases had severe disease. One hundred and forty-nine (12.9%) cases had underlying diseases among the total cases; 56% of the patients who had severe disease had an underlying condition (p < 0.01). The need for hospitalization did not differ between patients who had an underlying condition and those who do not have (p = 0.38), but the need for intensive care was higher in patients who had an underlying condition (p < 0.01). Forty-seven (31.5%) of the cases having underlying conditions had asthma or lung disease (38 of them had asthma).Conclusions: To the best of our knowledge, this is one of the largest pediatric data about confirmed COVID-19 cases. Children from all ages appear to be susceptible to COVID-19, and there is a significant difference in symptomatology and laboratory findings by means of age distribution.

Background: Paediatric HIV infection is different from the adult type of disease in many ways, including transmission routes, clinical findings and treatment strategies. Aims: To evaluate clinical data of paediatric patients with HIV disease. Study Design: Retrospective cross-sectional study. Methods: The charts of 22 paediatric patients diagnosed with HIV infection in our clinic during a 14 year period through 2001-2015 were retrospectively analysed. Clinical data, laboratory findings, treatment modalities and outcomes were recorded. Results: The mean age of diagnosis 61.9±49.2 months and the mean follow-up period was 60.3±37.5 months. Seven patients (31.8%) were foreigners and the most common transmission route was vertical transmission (n=16, 72.7%). The most common presenting symptom and the sign were history of recurrent upper respiratory tract infections (n=8, 36.4%) and lymphadenopathy (n=12, 54.5%), respectively. Recurrent pneumonia (n=6, 27.3%), prolonged fever (n=5, 22.7%), recurrent otitis media (n=4, 18.2%), and gastroenteritis (n=4, 18.2%) were other clinical symptoms. Other than bacterial sinopulmonary infections, tuberculosis was the most frequent opportunistic infection (n=3, 13.6%). Mortality occurred in two patients (9.1%). Conclusion: Although mostly vertically transmitted, HIV infection may be diagnosed throughout the childhood. Frequently encountered signs and symptoms may be the reason for doctor admission. High clinical suspicion together with detailed anamnestic data and physical findings constitute the basis for pediatric HIV diagnosis

Background: Clinical vaccine failure is the occurence of the specific vaccine-preventable disease in an appropriately and fully vaccinated person after enough time has elapsed for protection against the antigens of the vaccine to develop. Fully immunized cases with pneumoccal vaccine may sometimes develop a complicated pneumonia with empyema caused by a vaccine serotype. Case Report: A 2 year-old male patient was admitted with the complaints of fever. On the basis of findings and laboratory results, the patient was diagnosed as having empyema. He was successfully treated with parenteral antibiotics and chest tube drainage. The pleural fluid culture and hemoculture of the patient yielded penicillin-susceptible pneumococci and the isolate was identified as serotype 9V. The patient had been vaccinated with a 13-valent pneumococcal conjugate vaccine according to the Turkish national immunization schedule at 2, 4, 6 and 12 months of age. His medical history and basic immunological profile were inconsistent with a primary immunodeficiency. Conclusion: The failure of the PCV13 vaccine may results in a complicated pneumonia with empyema. It is important to investigate serotypes of pneumococci in these cases to determine other possible vaccine failures due to PCV13 and to study the underlying mechanisms

Objective: To investigate the clinical impact of vancomycinresistant enterococci (VRE) colonization in patients with hematologic malignancies and associated risk factors. Materials and Methods: Patients colonized and infected with VRE were identified from an institutional surveillance database between January 2010 and December 2013. A retrospective case-control study was performed to identify the risk factors associated with development of VRE infection in VRE-colonized patients. Results: Fecal VRE colonization was documented in 72 of 229 children (31.4%). Seven VRE-colonized patients developed subsequent systemic VRE infection (9.7%). Types of VRE infections included bacteremia (n=5), urinary tract infection (n=1), and meningitis (n=1). Enterococcus faecium was isolated in all VRE infections. Multivariate analysis revealed severe neutropenia and previous bacteremia with another pathogen as independent risk factors for VRE infection development in colonized patients [odds ratio (OR): 35.4, confidence interval (CI): 1.7-72.3, p=0.02 and OR: 20.6, CI: 1.3-48.6, p=0.03, respectively]. No deaths attributable to VRE occurred. Conclusion: VRE colonization has important consequences in pediatric cancer patients.

Background: Little is known about factors associated with carbapenem-resistant Klebsiella pneumoniae infections in pediatric patients, who are initally colonized with carbapenem-resistant Klebsiella pneumoniae. Materials and methods: A retrospective case–control study was conducted involving pediatric and neonatal intensive care units throughout a five-year period (January 2010–December 2014). Clinical and microbiological data were extracted from Hospital Infection Control Committee reports and patients’ medical records. Risk factors were assessed in carbapenem-resistant Klebsiella pneumoniae colonized patients who developed subsequent systemic infection (cases) and compared to carbapenem-resistant Klebsiella pneumoniae colonized patients who did not develop infection (controls). Results: Throughout the study period, 2.6% of patients admitted to neonatal intensive care units and 3.6% of patients admitted to pediatric intensive care units had become colonized with carbapenem-resistant Klebsiella pneumoniae. After a mean of 10.6 ± 1.9 days (median: 7 days, range: 2–38 days) following detection of colonization, 39.0% of the carbapenem-resistant Klebsiella pneumoniae colonized patients in pediatric intensive care units and 18.1% of carbapenem-resistant Klebsiella pneumoniae colonized patients in neonatal intensive care units developed systemic carbapenem-resistant Klebsiella pneumoniae infection. Types of systemic carbapenem-resistant Klebsiella pneumoniae infections included bacteremia (n = 15, 62.5%), ventilator-associated pneumonia (n = 4, 16.6%), ventriculitis (n = 2, 8.3%), intraabdominal infections (n = 2, 8.3%), and urinary tract infection (n = 1, 4.1%). A logistic regression model including parameters found significant in univariate analysis of carbapenem resistant Klebsiella pneumoniae colonization and carbapenem resistant Klebsiella pneumoniae infection groups revealed underlying metabolic disease (OR: 10.1; 95% CI: 2.7–37.2), previous carbapenem use (OR: 10.1; 95% CI: 2.2–40.1), neutropenia (OR: 13.8; 95% CI: 3.1–61.0) and previous surgical procedure (OR: 7.4; 95% CI: 1.9–28.5) as independent risk factors for carbapenem-resistant Klebsiella pneumoniae infection in patients colonized with carbapenem-resistant Klebsiella pneumoniae. Out of 24 patients with carbapenem resistant Klebsiella pneumoniae infection, 4 (16.6%) died of carbapenem-resistant Klebsiella pneumoniae sepsis. Conclusion: Asymptomatic colonization with carbapenem-resistant Klebsiella pneumoniae in intensive care units of pediatric departments should alert health care providers about forthcoming carbapenem-resistant Klebsiella pneumoniae infection. Those carbapenem-resistant Klebsiella pneumoniae colonized patients at risk of developing infection due to carbapenem-resistant Klebsiella pneumoniae may be targeted for interventions to reduce subsequent infection occurence and also for timely initiation of empirical carbapenem-resistant Klebsiella pneumoniae active treatment, when necessary. Keywords: Carbapenem resistant Klebsiella pneumoniae, Infection, Colonization, Pediatric/Neonatal intensive care

Influenza virus can cause serious complications, especially in patients with comorbid illnesses. Acute respiratory distress syndrome (ARDS) is among the most common causes of influenza-related morbidity and mortality. Herein we present the case of a boy with a genetic disorder who recovered from influenza-related ARDS. A 3-year-old boy with 3p deletion syndrome was admitted for refractory cough and fever. During his follow-up, sudden respiratory failure concomitant with ARDS occured. He was transferred to the pediatric intensive care unit (PICU) and intubated. Broad-spectrum antibiotherapy and oseltamivir were administered. Nazopharnygeal swab polymerase chain reaction (PCR) analysis revealed H1N1. Venitalition parameters were set according to that recommended for ARDS. On the ninth day of his admission, the patient was discharged from PICU. Appropriate ventilation strategies together with early oseltamivir therapy improves outcomes of influenza-related ARDS.

The use of TNF-alpha inhibitor agents facilitates mycobacterial infections. Unlike in normal population, active tuberculosis in such patients may be asymptomatic. Here we present the case of an asymptomatic child who developed pulmonary tuberculosis during TNF-alpha inhibitor therapy. A 12-year-old child with a diagnosis of juvenile idiopathic arthritis and uveitis was referred to our clinic before initiation of adalimumab therapy. His tuberculin skin test was negative and chest X-ray was normal prior to therapy. On the third month of his therapy, his father was diagnosed with pulmonary tuberculosis, and he was initiated on isoniazid therapy. A month later, the patient’s tuberculin skin test was measured as 7 mm, and chest X-ray revealed paratracheal opacity. Computerized tomographic scan confirmed a necrotic mass lesion with a size of 40x27x24 mm which was compatible with tuberculosis. He was thus initiated on antituberculosis therapy. Patients undergoing anti TNF-alpha therapy should be followed up for tuberculosis before and during therapy.

In the last decade, autosomal recessive IL-12Rβ1 deficiency has been diagnosed in four children with severe tuberculosis from three unrelated families from Morocco, Spain, and Turkey, providing proof-of-principle that tuberculosis in otherwise healthy children may result from single-gene inborn errors of immunity. We aimed to estimate the fraction of children developing severe tuberculosis due to IL-12Rβ1 deficiency in areas endemic for tuberculosis and where parental consanguinity is common.We searched for IL12RB1 mutations in a series of 50 children from Iran, Morocco, and Turkey. All children had established severe pulmonary and/or disseminated tuberculosis requiring hospitalization and were otherwise normally resistant to weakly virulent BCG vaccines and environmental mycobacteria. In one child from Iran and another from Morocco, homozygosity for loss-of-function IL12RB1 alleles was documented, resulting in complete IL-12Rβ1 deficiency. Despite the small sample studied, our findings suggest that IL-12Rβ1 deficiency is not a very rare cause of pediatric tuberculosis in these countries, where it should be considered in selected children with severe disease.This finding may have important medical implications, as recombinant IFN-γ is an effective treatment for mycobacterial infections in IL-12Rβ1-deficient patients. It also provides additional support for the view that severe tuberculosis in childhood may result from a collection of single-gene inborn errors of immunity.

In the evaluation and management of bronchial asthma, simple instruments for measurements of the peak expiratory flow (PEF) rate are needed. The aim of this study was to determine normal PEF values of Turkish children living in Istanbul. This is the largest study conducted in Turkey. In a cross-sectional study, we measured PEF in 2791 healthy school children (1468 boys and 1323 girls) aged 7-14 years, with a Mini Wright peak flow meter. We entered height, age, and sex into the regression equation. The equation for prediction of PEF in boys was calculated as (3.5 × height [cm]) + (9.2 × age [years]) - 256.5, (p < 0. 0001; r = 0.83) and for girls as (3.3 × height [cm]) + (10.2 × age [years]) - 263.7 (p < 0.0001; r = 0. 81). We found that PEP' values of Turkish children were similar to British and Danish children, but significant differences were noted with Greek, Irish, Mexican American, African-American, and white American children. Our results were significantly lower compared with another study conducted in Adana, a small southern city (<1 million inhabitants) in Turkey. Istanbul being a cosmopolitan big city (>7 millions inhabitants) can reflect more reliably real PEP' values of Turkish children. We concluded that our findings would serve as an important basis for preparing centile curves for normal PEP' values for Turkish children. [ABSTRACT FROM AUTHOR]