Strain Selection and Statistical Optimization of Culture Conditions for 19F Polysaccharide Production from Pneumococcus

Introduction:  Capsular polysaccharides of pneumococci are principle antigenic constituents of vaccines against pneumococci. Enhancing the yield of capsule production decreases costs of these vaccines and increases the vaccine coverage in developing countries. In this study therefore, we aim to optimize the capsule production from serotype 19F pneumococcus in terms of the applied pneumococcal strain and environmental culture conditions.Materials and Methods:  Thirteen serotype 19F Streptococcus pneumoniae strains were screened for the capsule production in modified Hoeprich culture medium using the stains all assay. The optimal ranges of environmental culture conditions for the selected strain were determined using single factor at a time (SFAT) strategy and utilized for the design of experiments based on the response surface methodology (RSM).Results:  S. pneumoniae 82218 showed the highest capsule production, and thus used for further studies. The maximum capsule production (1.364 mg/ml) was attained under optimal conditions (pH 7.26, 35.5 ºC, 30 rpm) predicted by the RSM derived quadratic model. The capsule production under the optimal conditions increased to 1.9 mg/ml using the buffered culture medium. Conclusion:  These results are much higher than those reported for pneumococcal capsule production in published studies [1, 2] and thus can be used to design suitable systems for the serotype 19F capsule production in the vaccine manufacturing process.

Reliability of Ultrasound for diagnosis of appendicitis in children

Introduction: In the medical world, acute appendicitis is one of the common surgeries. The Aim of this study is determining reliability of ultrasound in acute appendicitis. Materials and Methods: The ethical code has been gotten in this research firstly. Based on the archives at Mofid Hospital, the list of appendectomy children in a six- months period has been extracted when they used the ultrasound prior to surgery. Demographic data, medical history and findings of appendicitis, even during the surgery, have been recorded using designed questionnaire based on patients’ documents. According to the surgeon report, not only have appendicitis patients  been operated but also confirmed. The ultrasound results have been compared with surgical results (as the gold standard). For each of the ultrasound findings, based on SPSS software as has used for analyzing, some parameters have been calculated such as sensitivity index, specificity, positive and negative predictive value, accuracy and area under the ROC curve.  Results:     In this study, 111 children with diagnosis of appendicitis have been operated. Based on the ultrasound prior to surgery, 71 patients (64%) with purulent appendicitis showed direct sonographic signs of appendicitis, 11 patients (9.9%) showed indirect signs, 6 patients (5.4%) revealed complicated signs, 7 patients (6.3%) with mesenteric lymphadenopathy and 16 patients (14.4%) negative in ultrasound. Also, according to the final diagnosis after surgery, 105 patients (94.6%) had appendicitis and 6 people (5.4%) were negative for appendicitis. The significant relationship was found between the ultrasound results prior to surgery and the final diagnosis after surgery for patients (p<0.05). The diagnostic value of ultrasound results prior to surgery in order to determine the appendicitis in children undergoing surgery has been revealed by different factors such as sensitivity, specificity, positive predictive value, negative predictive value and accuracy . These factors are at 83.8%, 100%, 100%,83% and 92.3%, respectively (p< 0.05). Conclusion:   It seems that Ultrasound prior to surgery is the useful method to determine the children appendicitis

Clinical Characteristics and Mortality of a Hospitalized 13 Years Old Patient with Covid-19: A Case Report

The corona virus is a global problem that threatens human life. According to the latest data from different countries the mortality of this virus in children is less than adult. A 13-year-old girl was hospitalized for 6 months following a gunshot trauma and its complications. When her general condition was finally improving, she was diagnosed with the corona virus and passed away. Children who are suffering from underlying diseases and need medical care are at a higher risk of death from the corona virus

Prevalence of resistance to colistin, tigecycline and minocycline in Acinetobacter baumannii isolated from clinical samples in 2014

Background: Colonization rate of Acinetobacter baumannii is increasing in hospitalized patients especially in long term hospitalized one and / or who were treat with extended spectrum antibiotics or anticancer. Antibiotic resistance in A. baumannii is considerable because more prevalence of them cause nosocomial infections and can impose high cost to health systems and patients. The aim of this study was determination of tigecycline, minocycline and colistin resistance A. baumannii in selected center in Tehran, Iran. Materials and Methods: This study was descriptive and functional foundation. In this study A. baumannii were collected from Milad, Mofid, Taleghani, Motahari and Loghman hospital, Tehran and transferred to laboratory of pediatric infections research center. Collected bacteria were identified by conventional microbiology tests. Antibiotic susceptibility testing was determined according to CLSI guide line. Tigecycline, minocycline and colistin resistance strains were isolated.  Results: In this study, 105 A. baumannii were collected from five selected hospitals: 48 (46%) from Milad, 33 (31%) from Motahari, 17 (16%) from Loghman, 4 (4%) from Mofid and 3 (3%) from Taleghani hospital. The highest resistance was observed against cefepime and high frequency of carbapenem and minocycline was observed. On the other hand, observed resistance to aminoglycosides was 93% at least. Tigecycline is the most effective antibiotic after colistin. Colistin resistant confirmed just in one isolate by E. test. Conclusion: The results of this study indicated that high rate of antibiotic resistance in A. baumannii even resistant to third and fourth generation of cephalosporin and carbapenem antibiotics. The treatment of MDR strains of A. baumannii become more complicated if the spread of them were not been controlled

Determining the coverage and efficacy of the COVID-19 vaccination program at the community level in children aged 12 to 17 in Tehran

Background: The vaccination is one of the acceptable and recomended solution to prevent and control of COVID-19. The aim of this study was to determine the efficacy of sinopharm vaccination in children aged 12–17 in Tehran. Methods: The case population study was performed from October 2021 to March 2022 among 1,500 children with positive PCR test reffered in Mofid Children’s Hospital in Tehran. 64 children aged 12–17 years were included. The data were collected by the hospital information system (HIS), vaccination information registration systems and questionnaire with their families. The coverage and efficacy of vaccination determined with equels commented by WHO. Results: Out of 64 children, 52 children were 12 to 15 years old (13.35±1.08), 12 children were 16 to 17 years old (16.55±0.52). 48.4% had received two doses of vaccine. The highest rate of positive PCR was observed in February 2022. Sinopharm vaccine coverage in this age group was 93.6% for the first dose and 81.1% for the second dose. Based on this information, 48.4% children in this study have received two complete doses of the COVID-19 vaccine. The efficacy of the vaccine was estimated as 94.4% (95% CI 90.2 to 97.7).Conclusion: It seems the coverage of Sinopharm vaccination in the age group of 12–17 years in Tehran is favorable and has high efficacy in this age group. In order to obtain more accurate and comprehensive estimation, it is recommended to take a sample on a wider level of the community

Distribution of capsular types and drug resistance patterns of invasive pediatric Streptococcus pneumoniae isolates in Teheran, Iran

Objectives: To explore the serotype distribution and drug resistance patterns of invasive pneumococcal isolates from children under 5 years of age. Methods: During a 32-month period, 585 clinical samples (including blood, cerebrospinal fluid (CSF), and synovial fluid) from children suspected of having meningitis, sepsis, pneumonia, or septic arthritis were analyzed using the BACTEC culture system. Positive cultures were examined using biochemical tests and lytA amplification for the identification of pneumococcal strains. The confirmed pneumococcal isolates were examined to determine capsular types using a modified sequential multiplex PCR and susceptibility to antimicrobial agents. Results: Fifty-three pneumococcal isolates were detected in the 585 clinical samples: 21 (39.6%) blood samples and 32 (60.4%) CSF samples. The most frequent serotype was 23F (24.5%), followed by serotypes 19F (18.9%), 19A (7.5%), and 9V (7.5%). Twenty-one percent of pneumococcal isolates were penicillin-non-susceptible and serotype 19A was significantly associated with resistance to penicillin. Conclusions: This study indicated that the 13-valent pneumococcal conjugate vaccine (PCV13) could cover the majority of the invasive pneumococcal isolates. Drug-resistant and multidrug-resistant Streptococcus pneumoniae strains are circulating in Iran. Therefore, public immunization of infants using PCV13 is recommended to reduce the incidence of pneumococcal disease and pneumococcal-resistant strains in Teheran

Investigation of prevalence of Shigella sonnei in children with diarrhea admitted to two hospital Emam Khomeini and Milad in Tehran in 1391 with Antimicrobial susceptibility of isolates

Background and Aim: Shigella infection is one of the prevalent causes of diarrhea disease in most developing countries in children under 10 years old. Conventional microbiological examination to identify Shigella species are time-consuming and requires a lot of work and cost. The object of the present research was to isolate and identify of serotypes of Shigella, Shigella sonnei from patients with bacillary dysentery and to detect their one major virulence genes ipaH by using PCR. Materials and Methods: 3000 stool sample from children with diarrhea admitted in two famous hospitals in1391 in summer & autumn in Tehran were used in this study. The identification of isolated was done by serogrouping and biochemical test & the prevalence of ipaH gene determined by PCR method using specific pairs of primers. Antimicrobial susceptibility of isolates was performed according to the CLSI guidelines. Results: All Shigella spp isolates in this study harbored the ipaH gene. Out of 160 shigella isolates, 50 isolates determined as S. sonnei with serogrouping and biochemical test. 90% of isolates were resistant to Tetracycline, Cotrimoxazole, Streptomycin and Minocycline. Conclusions: We conclude that ipaH PCR procedure is more reliable, sensitive, easier, reproducible and specific which is significantly faster than current conventional detection assays such as serologic test. Althuogh in this study we report that among Shigella .spp cause diarrhea infection most of them are S .sonnei resistant antibiotic

Co-infection with dual Streptococcus pneumoniae serotypes as a cause of pediatric bacterial meningitis in Iran: a multi-center cross-sectional study

Abstract Background Meningitis is considered a life-threatening infection with high mortality all over the world. Hemophilus influenzae (H. influenzae) and Streptococcus pneumoniae (S. pneumoniae) are regarded as the two most common infectious agents causing bacterial meningitis. This study aimed to identify H. influenzae and S. pneumoniae serotypes in blood and cerebrospinal fluid (CSF) of pediatric patients with meningitis, using polymerase chain reaction (PCR). Methods This multi-center cross-sectional study included 284 children with suspected meningitis referred to 4 target hospitals. Overall, 412 samples (128 blood and 284 CSF samples) were obtained from the patients from November 14, 2016 to November 15, 2017. The extracted DNA was examined using multiplex real time PCR to screen for S. pneumoniae and H. influenzae. S. pneumoniae serotyping was also done by multiplex PCR. Results Out of 284 CSF specimens, 22 were positive for ply S. pneumoniae. Of 20 DNA samples meeting the Quality Control (QC) standards for serotyping, 7 (35%), 6 (30%), 2 (10%), 2 (10%), 2 (10%), 1 (5%), 1 (5%), 1 (5%), 1 (5%) and 1 (5%) were positive for serotypes 3, 11A, 6A, 14, 7C, 23F, 23B, 19A, and 19F and 5, respectively. Overall, nine samples were positive for two serotypes, of whom 3 and 11A were the most common from Tehran province. Of note, one of these CSF samples showed a new co-infection with serotypes 7C and 14. Also, 6 samples (30%) were positive for H. influenzae detected by bexA primer. None of the blood samples were positive for S. pneumoniae or H. influenzae. Conclusion Co-infection with S. pneumoniae serotypes can occur in bacterial meningitis and it might be missed if all serotypes are not evaluated in CSF specimens

Effect of Haemophilus influenzae Type b Vaccination on Nasopharyngeal Carriage Rate in Children, Tehran, 2019

Background. Haemophilus influenzae (H. influenzae) strains, which commonly reside as commensals within the human pharynx and can remain as an asymptomatic carrier, but become invasive leading to pneumonia, septic arthritis, or meningitis. The Pentavac (pentavalent vaccine, manufactured by India, SII (DTwP-HepB-Hib)) was introduced to the Iranian National Immunization Plan in November 2014. The aim of this study is to investigate H. influenzae type b (Hib) carrier rate among children under 6 years old in Tehran. Methods. This cross-sectional study was performed on 902 children including vaccinated/unvaccinated in the age of 6 months to 6 years, in Tehran. Sampling was performed from July 2019 to September 2019. Nasopharyngeal samples were taken from children by sterile swab. The PCR method was used to extract DNA. Then, all H. influenzae isolates were initially confirmed by molecular tests. BexA was used to distinguish typeable H. influenzae strains from nontypeable Haemophilus influenzae (NTHi). Results. A total of 902 children were enrolled in the study: 452 were female (51%). H. influenzae carriage rate was 267 (29%), of that 150 samples (16.6%) were typeable. The nasopharyngeal Hib carrier rate in the children was 2.6% (24/902). 262 cases did not receive Hib vaccine. Analysis in nonnursery’s children aged 4 to 6 (unvaccinated) years showed that the lower educational level of father, mother, and family number correlated with increased odds of colonization of children with Hib. Conclusion. Our findings showed a significant decrease (60%) in the overall Hib nasopharyngeal carriage in healthy children under six years after 5 years after the start of Hib vaccination