Sequence-type diversity of invasive Streptococcus pneumoniae isolates in Iran among children under 15 years of age.

Background: Infection with viruses, bacteria, or other pathogens can lead to inflammation of the meninges. Finding the pathogen and identifying the most common type is necessary for each country. Using multi-locus sequence typing (MLST), the aim of this study was to determine the genetic relationship among S. pneumoniae isolated from CSF in children with bacterial meningitis. Materials and methods: : Fourteen isolates of S. pneumoniae from CSF in children with bacterial meningitis were included in this study. The seven housekeeping genes, primer, and analysis of the sequencing used in MLST were extracted from PubMLST. Results: The sequencing analysis showed four MLST types in the studied strains. The most frequent type is ST13649 and the least frequent are ST708 and ST285. Conclusion: Finding the bacterial sequence types (ST) enables comparing the ST in different, especially neighbouring, countries.

Evaluation of the inhibitory effects of TiO2 nanoparticle and Ganoderma lucidum extract against biofilm-producing bacteria isolated from clinical samples.

The emergence of multidrug-resistant pathogens leads to treatment failure. So, the need for new antibacterial drugs is urgent. We evaluated the antibacterial and antibiofilm effects of titanium dioxide (TiO2) nanoparticles (NPs) and Ganoderma extract against biofilm-producing Pseudomonas aeruginosa and methicillin-resistant Staphylococcus aureus (MRSA) by microbroth dilution and crystal violet assays. The combined effect of these compounds was studied using the checkerboard method. The OD260 was measured to assess the destruction of the membrane permeability. The expression of biofilm-related genes (iacA and algD) was investigated by real-time PCR. MRSA isolate was more susceptible to test compounds. The OD260 increased and algD gene was down-regulated after treatment with TiO2 NPs and a combination of TiO2 NPs and Ganoderma extract. iacA gene did not affect by test compounds. Overall, these findings revealed that nanoparticles and natural substances might represent the potential candidates to develop promising antibacterial agents, especially against Gram-positive bacteria.

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

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.

Antimicrobial effect of silver and gold nanoparticles in combination with linezolid on Enterococcus biofilm.

Background and Objectives: In the past few years, application of new antimicrobial e.g. nanoparticles (NPs) to treat infection caused by drug-resistant bacteria has increased. This study aimed to determine antimicrobial property of silver nanoparticles (AgNPs) and gold nanoparticles (AuNPs) in combination with linezolid on Enterococcus biofilm. Materials and Methods: A total of forty-eight isolates of Enterococcus spp. were collected and confirmed by PCR method. The synthesis of biocompatible AgNPs was performed, then analyzed by Fourier Transform Infrared spectroscopy (FTIR), Scanning Electron Microscopy (SEM), and Transmission Electron Microscopy. We carried out minimum inhibitory concentration (MIC) and biofilm forming capacity of AgNPs and AuNPs with linezolid. Results: Twenty-two E. faecium isolates and twentysix E. faecalis investigated in this study. Strong biofilm formation was seen in 12 (25%) of isolates, and others isolates (75%) formed moderate biofilm. AgNPs and Au-NPs size were 26 nm and 20 nm respectively. The MIC of AgNPs was 23.2 µg/ml, and AuNPs were 92.1 µg/ml and the lowest MIC was obtained 2 µg/ml in linezolid. Biofilm formation inhibitory activity by AuNPs + Linezolide and AgNPs + Linezolide 70 to 80 percent increased in average. Conclusion: The antibiofilm activity of AgNPs and AuNPs increased when both agents were used in combination with linezolid in comparison with each agent alone.

Molecular Characterization of Streptococcus Pneumoniae from Patients Diagnosed with Pneumonia: Recommendation for Vaccination Program.

Background: Infections caused by Streptococcus pneumoniae (S. pneumoniae) have remained a significant public health concern worldwide. In developed countries, the highest prevalence of S. pneumonia has been reported among the elderly. The aim of this study was to evaluate the coverage of genotypes in the 13-valent pneumococcal conjugate vaccine (PCV-13) in the Iranian elderly population. Methods: A total of 41 isolates of S. pneumoniae were collected in the current retrospective cross-sectional study. The samples comprised 33 inpatients hospitalized for pneumococcal pneumonia and 8 outpatients. Multiplex polymerase chain reaction assay was performed to categorize the bacteria isolated into specific genotypes. Statistical analyses were performed using SPSS software, and the chi-square test was used to assess the statistical significance in percentages. Results: A total of 68 genotypes were identified in this study, in which 39 isolates (57.3%) were associated with invasive infections. The most common genotypes were 6A/B [8 (19.5%)], 1 [7 (17.5%)], 14 [5 (12.2%)], and 19A [4 (9.75%)], respectively. The coverage rates of PCV-7, PCV-10, and PCV-13 vaccines were 51.17%, 70.7%, and 99.9%, respectively. According to our results, the pneumococcal coverage rate of PCV-7, PCV-10, and PCV-13 vaccine types is estimated to be 51.2%, 70.7%, and 99.9%, respectively. Furthermore, the trend of pneumococcal serotypes included in the PCV-13 was steadily increasing during the study period. Conclusion: It can be concluded that the most circulating pneumococcal serotypes were in accordance with specific serotypes included in the PCV-13 vaccine types. Therefore, including PCV-13 vaccines in immunization programs against pneumococcus in the elderly can effectively reduce the rate of infections.

Epidemiology of Pseudomonas aeruginosa in cystic fibrosis patients in Iran: A systematic review and meta-analysis.

The present study aims to investigate the prevalence of Pseudomonas aeruginosa in Iranian Cystic Fibrosis (CF) patients. We conducted a systematic search on this topic in Web of Science, PubMed, Embase, Scopus, and Google Scholar electronic databases to the end of July 2019. Then, 14 articles with eligible criteria were selected for data extraction and analysis by Comprehensive Meta-Analysis Software. The pooled prevalence of P. aeruginosa was 40.6% (95% CI: 32.4%-49.4%) ranging from 32.4% to 49.4%. There was a significant heterogeneity among the studies (χ2 =21.02; p <0.001; I2 = 86.07%). The funnel plot for publication bias showed no evidence of asymmetry. Based on the results of Begg's and Egger's test no significant publication bias was observed. The study demonstrated a relative prevalence of P. aeruginosa among CF patients in Iran. Due to the rapid spread and infection severity of P. aeruginosa and other opportunistic pathogens, efforts are required to identify risk factors, reservoirs, transmission routes and source of infection.

Antibiotic Susceptibility Patterns and Prevalence of Streptococcus Agalactiae Rectovaginal Colonization Among Pregnant Women in Iran.

OBJECTIVE: Streptococcus agalactiae is an important pathogen in neonates and pregnant women. Neonatal invasive infections due to S. agalactiae are life-threatening and preventive strategies for this challenge of human have become a concern. The aim of the present study was to determine the prevalence of rectovaginal colonization, related risk factors and antibiotic resistance pattern of S. agalactiae among pregnant women in Iran. METHODS: The present study was performed on 240 pregnant women. Vaginal and rectal swabs were obtained from all of the women and then were transferred to the laboratory. The isolation and identification of S. agalactiae was performed by standard microbiological tests and polymerase chain reaction (PCR) assay. The antimicrobial susceptibility patterns of the isolates were determined by the Kirby-Bauer disk diffusion. Polymerase chain reaction was used to detect ermB and mefA genes in erythromycin-nonsusceptible isolates. RESULTS: Out of 240 pregnant women, 16 cases (6.7%) were colonized by S. agalactiae. There is no significant association between demographic-obstetric factors and maternal S. agalactiae colonization in the pregnant women. Linezolid, vancomycin and ampicillin were the most effective antibiotics against S. agalactiae. The ermB gene was present in 6 (35.29%) S. agalactiae isolates. However, the mefA gene was not detected in any of the isolates. CONCLUSION: Given the relatively significant prevalence of S. agalactiae colonization in the pregnant women in the present study and the risk of serious neonatal infections, the screening of pregnant mothers for the bacteria seems necessary. Our findings highlight the importance of appropriate antibiotic prophylaxis during pregnancy for the prevention of early onset S. agalactiae-neonatal infection and comorbidity.

Bacterial Etiology and Antibiotic Susceptibility of Conjunctivitis Patients' Isolates in Kashan, Iran.

BACKGROUND: Conjunctivitis is a very common ocular disease, which can be caused by a wide variety of microorganisms. This study was aimed to assess the bacterial etiology and antibiotic susceptibility of conjunctivitis patients' isolates from Central Iran. MATERIALS AND METHODS: This study was performed in 180 patients referred to the Department of Ophthalmology in Kashan University with symptoms of conjunctivitis from July 2017 to December 2017. To detect of different bacteria, Gram staining, morphological characterization, pigment production, biochemical characteristics, coagulase test, optochin and PYR tests, oxidase test, and culture on specific media were used. Antibiotic susceptibility of the bacteria isolated was done using the Kirby-Bauer method. Methicillin resistance in staphylococci isolated from the patients was identified using polymerase chain reaction technique. RESULTS: Of the 195 bacteria isolated, about 81.5% were Staphylococcus epidermidis and Staphylococcus aureus and the remaining 19.5% included other species. In the present study, Pseudomonas aeruginosa was most resistant to ampicillin. In the case of S. epidermidis and S. aureus, the highest resistance was observed against erythromycin and the least resistance was against rifampicin and linezolid. CONCLUSION: In this study, S. aureus and S. epidermidis are the most common causes of conjunctivitis in all age groups, however, this condition decreases with age and is also influenced by other factors such as season and weather conditions. The results of this study can be helpful in planning more prudent treatment strategies for patients with conjunctivitis in Kashan.

Antibiotic susceptibility patterns and prevalence of streptococcus agalactiae rectovaginal colonization among pregnant women in iran

Abstract Objective Streptococcus agalactiae is an important pathogen in neonates and pregnant women. Neonatal invasive infections due to S. agalactiae are life-threatening and preventive strategies for this challenge of human have become a concern. The aim of the present study was to determine the prevalence of rectovaginal colonization, related risk factors and antibiotic resistance pattern of S. agalactiae among pregnant women in Iran. Methods The present study was performed on 240 pregnant women. Vaginal and rectal swabs were obtained from all of the women and then were transferred to the laboratory. The isolation and identification of S. agalactiae was performed by standard microbiological tests and polymerase chain reaction (PCR) assay. The antimicrobial susceptibility patterns of the isolates were determined by the Kirby-Bauer disk diffusion. Polymerase chain reaction was used to detect ermB and mefA genes in erythromycin-nonsusceptible isolates. Results Out of 240 pregnant women, 16 cases (6.7%) were colonized by S. agalactiae. There is no significant association between demographic-obstetric factors and maternal S. agalactiae colonization in the pregnant women. Linezolid, vancomycin and ampicillin were the most effective antibiotics against S. agalactiae. The ermB gene was present in 6 (35.29%) S. agalactiae isolates. However, the mefA gene was not detected in any of the isolates. Conclusion Given the relatively significant prevalence of S. agalactiae colonization in the pregnant women in the present study and the risk of serious neonatal infections, the screening of pregnant mothers for the bacteria seems necessary. Our findings highlight the importance of appropriate antibiotic prophylaxis during pregnancy for the prevention of early onset S. agalactiae-neonatal infection and comorbidity.

Characterization of Staphylococcus aureus Biofilm Formation in Urinary Tract Infection.

BACKGROUND: The aim of this study was to investigate the antibiotic susceptibility pattern as well as the phenotypic and genotypic biofilm formation ability of Staphylococcus aureus isolates from patients with urinary tract infection (UTI). METHODS: A total of 39 isolates of S. aureus were collected from patients with UTI. The antibiotic susceptibility patterns of the isolates were determined by the Kirby-Bauer disk-diffusion. We used the Modified Congo red agar (MCRA) and Microtiter plate methods to assess the ability of biofilm formation. All isolates were examined for determination of biofilm related genes, icaA, fnbA, clfA and bap using PCR method. RESULTS: Linezolid, quinupristin/dalfopristin and chloramphenicol were the most effective agents against S. aureus isolates. Overall, 69.2% of S. aureus isolates were biofilm producers. Resistance to four antibiotics such as nitrofurantoin (71.4% vs. 28.6%, P=0.001), tetracycline (57.7% vs. 42.3%, P=0.028), erythromycin and ciprofloxacin (56% vs. 44%, P=0.017) was higher among biofilm producers than non-biofilm producers. The icaA, fnbA and clfA genes were present in all S. aureus isolates. However, bap gene was not detected in any of the isolates. CONCLUSION: Our findings reinforce the role of biofilm formation in resistance to antimicrobial agents. Trimethoprimsulfamethoxazole and doxycycline may be used as an effective treatment for UTI caused by biofilm producers S. aureus. Our results suggest that biofilm formation is not dependent to just icaA, fnbA, clfA and bap genes harbor in S. aureus strains.

Molecular typing of methicillin-resistant and methicillin-susceptible Staphylococcus aureus isolates from Shiraz teaching hospitals by PCR-RFLP of coagulase gene.

BACKGROUND AND OBJECTIVES: To investigate coagulase gene polymorphism of MRSA and MSSA isolates from Shiraz teaching hospitals from 2011 to 2012. MATERIALS AND METHODS: A total of 302 isolates of Staphylococcus aureus were collected from clinical specimens in three major teaching hospitals and confirmed on the basis of morphological characteristics and biochemical tests. The isolates were subjected to molecular typing on the basis of coagulase enzyme gene polymorphism by PCR-RFLP. RESULTS: There were 27 and 28 different RFLP patterns for AluI and HaeIII restriction enzymes respectively. This study showed that the discriminatory power of coagulase gene typing by Hae III enzyme was more than that of Alu I enzyme. CONCLUSION: PCR-RFLP method is rapid, reproducible, simple and efficient for typing Staphylococcus aureus isolated from clinical specimens. This study showed that Hae III discriminatory power is better than Alu I for typing Staphylococcus aureus isolates.