Antibiotic Susceptibility and Biofilm Formation of Bacterial Isolates Derived from Pediatric Patients with Cystic Fibrosis from Tehran, Iran.

Cystic fibrosis (CF) is a genetic disease with a high rate of morbidity and mortality. Children with CF commonly suffer from recurrent and persistent pulmonary tract infections caused by diverse bacterial pathogens. This study aimed to investigate the prevalence, antimicrobial susceptibility, and biofilm formation of bacterial isolates in pediatric patients with CF. The study population of this cross-sectional study included 8,908 children suspected to have CF by clinical manifestations from March 2015 to August 2017 who were referred to the Tehran Pediatric Central Hospital, Iran. The tests carried out for each participant included screening sweat test, sputum culture, antibiotic susceptibility test using Kirby-Bauer disk diffusion method, and biofilm formation in microtiter plates method. Based onclinical examination and screening sweat test, 183 (2.05 %( out of 8,908 children, were positive for CF. The mean age of children was estimated at 2.93 years, and the majority of them were male (n=103, 56.2%). No gender-specific difference was observed in CF disease in this study (P>0.05). In addition, the results of sputum culture showed that 153 (83.6%) microorganisms (bacteria and fungi) were collected from CF patients. Normal flora was isolated in 30 (16.4%) patients and more than one bacterial species were isolated in 7.2% of patients. The obtained results indicated that Pseudomonas aeruginosa was the most prevalent isolated bacteria followed by Staphylococcus aureus, and Klebsiella pneumoniae. Based on the antibiotic susceptibility test results, P. aeruginosa and piperacillin/tazobactam had the highest (11.7%) and the lowest (2.3%) resistance rate against gentamicin, respectively. However, all K. pneumoniae isolates were resistant to Cefotaxime. Among S. aureus isolates, 83.4% and 16.6% were methicillin-susceptible Staphylococcus aureus and Methicillin-resistant Staphylococcus aureus respectively. Concerning biofilm formation, 76%, 67%, and 72.5% of P. aeruginosa, S. aureus, and K. pneumoniae isolates were biofilm producers, respectively. Based on the study results, P. aeruginosa was the dominant pathogen in pediatric patients with CF from Tehran, Iran, and most of the pathogens were biofilm producers. No severe antibiotic resistance was observed in the isolates; however, the anti-microbial resistance profile should be carefully checked in CF patients on a regular basis.

Serogroups, and drug resistance of nontyphoidal Salmonella in symptomatic patients with community-acquired diarrhea and chicken meat samples in Tehran.

BACKGROUND: Salmonella is considered as a main cause of community-acquired diarrhea in humans, however, sources of the multi-drug resistant (MDR) strains and their link with the disease are not well known. AIMS: This study aimed to investigate the frequency, serogroup diversity, and antimicrobial susceptibility patterns of Salmonella strains in poultry meat and stool samples of patients with community acquired diarrhea in Tehran. METHODS: We compared the frequency of non-typhoidal Salmonella serogroups, the similarities of their resistance patterns to 10 antimicrobial compounds, the prevalence of extended spectrum ß-lactamase (ESBL) and ampicillinase C (AmpC) genetic determinants, and class 1 and 2 integrons in 100 chicken meat and 400 stool samples of symptomatic patients in Tehran during June 2018 to March 2019. RESULTS: Salmonella was isolated from 75% and 5.5% of the chicken meats and human stool samples, respectively. The chicken meat isolates mainly belonged to serogroup C (88%, 66/75), while the human stool isolates were mainly related to serogroup D (59.1%, 13/22). The MDR phenotype and the most common rates of resistance to antibiotics, including tetracycline, trimethoprim/sulfamethoxazole (TS) and azithromycin, were detected in 4.5% and 45.3%, 59% and 13.6%, 43% and 9.1%, 42% and 9.1% of the human stool and chicken meat samples, respectively. Carriage of bla CTX, bla SHV, and bla PER genes in the meat isolate with ESBL resistance phenotype and bla ACC, bla FOX, and bla CMY-2 among the 7 meat strains with AmpC resistance phenotype was not confirmed using polymerase chain reaction (PCR). High prevalence of class 1 and 2 integrons was characterized and showed a correlation with resistance to TS and chloramphenicol. CONCLUSION: These findings showed a lack of association between chicken meats and human isolates due to discrepancy between the characterized serogroups and resistance phenotypes.

Isospora belli associated recurrent diarrhea in a child with AIDS.

Persistent diarrhea is a major manifestation of Acquired Immunodeficiency Syndrome (AIDS) which might be more complicated in Human Immunodeficiency Virus (HIV) infected children especially those from developing countries. There are numerous reports showing the emergence of intestinal opportunistic coccidian parasites, mostly Cryptosporidium parvum and Isospora belli in HIV-infected individuals. The prevalence of isosporiasis is probably underestimated in developing countries because routinely not all HIV-infected patients are examined for the presence of this protozoan infection. Here we report a case of HIV-infected isosporiasis presenting with failure to thrive and persistent diarrhea. Since I. belli infection in children responds well to therapy with trimethoprim-sulfamethoxazole, isosporiasis should be considered as a treatable infection in AIDS, if it is detected at proper time.

Comparison of the RE and B1 gene for detection of Toxoplasma gondii infection in children with cancer.

Early, accurate and effective diagnosis of toxoplasmosis can make an important contribution to the prevention and control of disease, especially in people who are at risk. In this study, two commonly used genomic repeats of Toxoplasma gondii, RE (GenBank accession number AF146527) and B1, were compared to each other in nested-PCR assay. Five hundred and thirty-five blood samples from children with leukemia were tested for the presence of T. gondii antibodies using enzyme immunoassays. One hundred and ten DNA samples of these patients (50 IgM+, IgG+, 10 IgM-, IgG+, and 50 IgM-, IgG-) were analyzed by nested-PCR. The specificity of two nested PCR assays was determined using the DNA samples of other parasites and human chromosomal DNA. As a result, 82% (41/50) and 68% (34/50) of the IgM+, IgG+ samples were positive on duplicate RE and B1-nested PCR analyses, respectively. None of the 10 IgM-, IgG+ seropositive samples was detected positive after testing RE and B1-nested PCR assays in duplicate. One (2%) of the 50 seronegative samples was positive by duplicate RE-nested PCR but none of them were positive by duplicate B1-nested PCR. The detection limit of the RE-nested PCR assay was 640 fg of T. gondii DNA whereas this rate for B1-nested PCR was 5.12 pg of the DNA template. No cross-reactivity with the DNA of other parasites and human chromosomal DNA was found. The results indicate that an RE-based nested PCR assay is more sensitive than B1 genomic target, of those tested, for detection of T. gondii. It is noteworthy that in comparison with B1-nested PCR, RE-nested PCR could detect the T. gondii DNA in seronegative samples too.

Prevalence of intestinal parasites among children referred to Children's Medical Center during 18 years (1991-2008), Tehran, Iran.

Epidemiological studies show that parasitic inections are among the most common infections and one of the biggest health problems of the society worldwide. Children at school age have the highest morbidity compared with other ages. Therefore, by treating these children, the disease burden in the total population is reduced. In this study, prevalence of parasitic infection in children referred to Children's Medical Center was compared in different years. In this retrospective cross-sectional study, the subjects were children under 13 years who were referred to Children's Medical Center Laboratory during 18 years (1991-2008) and underwent stool exam by any reason. The specimens were evaluated by different common methods of stool parasitology. In suspected cases, parasites was cultured in specific medium and stained as needed. Required data were obtained from the laboratory files and analysed according to study's purpose. Subjects were 124 366 children. Among them, 0.78% of cases had parasitic infections and 60.54% cases were male. Parasitic infections were related to protozoa in 95.33% cases and intestinal worms in 4.87%. Of them, 50.352% were pathogenic protozoa. The most parasitic infection was Giardia lamblia. Among intestinal worms, the highest prevalence was related to Hymenolepis nana (40.7%). A comparison between the first 10 years and the next 8 years of the study showed that the prevalence of intestinal parasites were 8% and 1% (P < 0.001) and the rate for protozoal infection were 14.9% and 4.3%, respectively (P < 0.001). The prevalence of intestinal parasites was reduced during recent years; however, more attempts should be performed to make it lower.