USE OF A MODIFIED FLUORESCENT IN SITU HYBRIDIZATION PROCEDURE TO IMPROVE THE IDENTIFICATION OF STREPTOCOCCUS PNEUMONIAE IN BLOOD CULTURES

Streptococcus pneumoniae is an important causative agent for bacteremia. Fluorescent in situ hybridization (FISH) is a helpful molecular technique for the rapid identification of S. pneumoniae in positive blood cultures. There are many reports concerning the application of an enzymatic treatment with lysozyme in the FISH procedure for partial cell wall digestion of S. pneumoniae. However, this study was aimed to test the FISH procedure without enzymatic treatment for the identification of S. pneumoniae in blood culture specimens. Seventy-seven positive blood culture specimens containing Gram-positive cocci were examined by both the conventional laboratory methods and FISH. Detection of S. pneumoniae was performed by two FISH procedures: one procedure was performed with an enzymatic treatment step and the other one was done without enzymatic treatment. In addition, the specimens were tested by the FISH procedure with enzymatic treatment to detect Streptococcus pyogenes and Enterococcus. The specificity of FISH in comparison with conventional culture methods was 100%. The sensitivity of the FISH procedure with enzymatic treatment for the detection of S. pneumoniae was 90%, whereas, the sensitivity of the FISH procedure without enzymatic treatment was 100%. In fact, by omission of enzymatic treatment, detection of S. pneumoniae was improved in 6 specimens. The results of the FISH and culture methods for the detection of S. pyogenes and Enterococcus were compatible. Altogether, FISH procedure without enzymatic treatment step seems to improve the detection of S. pneumoniae in some case

Evaluation of fluorescent in situ hybridization for rapid diagnosis of enterococcal wound infection

Enterococci are among prominent causes of nosocomial wound infections. Since the rapid detection of causative agents could make earlier administration of choice antibiotics and quick recovery of patients, so the application of rapid diagnostic methods is important. Therefore, this study was designed to evaluate fluorescent in situ hybridization (FISH) for the detection of Enterococcus in wound swab samples. The time needed for FISH procedure is about 3 h. Specimens taken from 33 hospitalized patients were examined by both FISH and culturing procedures. By using conventional culture, 10 of 33 wound samples were culture-positive. Out of these 10 specimens, eight were FISH-positive, but two specimens were FISH-negative for Enterococcus. The remaining 23 wound specimens were Enterococcus negative according to the both methods. Therefore, the specificity of FISH was 100%; however, this method showed 80% sensitivity. Because of high specificity of FISH, the combined application of FISH and cultivation methods would be suggested for detection of enterococci from wound specimens in situations in which rapid diagnosis has an advantage in the treatment of patients

Identification of Streptococcus agalactiae by fluorescent in situ hybridization compared to culturing and the determination of prevalence of Streptococcus agalactiae colonization among pregnant women in Bushehr, Iran

Background: Pregnant women colonized by Streptococcus agalactiae (group B streptococci [GBS]) may transfer this microorganism to their newborns. S. agalactiae is an important cause of pneumonia, sepsis, and meningitis in newborns. Fluorescent in situ hybridization (FISH) is considered as a method of identification in the field of diagnostic microbiology. In this paper, we have designed a study to compare the DNA FISH after 7 h Lim broth enrichment and culturing for the identification of S. agalactiae and to determine the prevalence of vaginal colonization by S. agalactiae among pregnant women in Bushehr, Iran. Methods: Vaginal swab specimens were obtained from 285 pregnant women at 35 weeks or more than 35 weeks of gestation. The specimens were inoculated into Lim broth. In order to evaluate the sensitivity and specificity of GBS DNA FISH after 7 h Lim broth enrichment, the specimens were tested using both FISH and conventional culture methods. In addition, the prevalence of GBS colonization was determined. Results: Based on the results of this study, both the sensitivity and specificity of FISH were 100%. S. agalactiae was detected by both culture and FISH in 27 of the 285 pregnant women. Thus, the prevalence of GBS colonization was 9.5%. Conclusions: Since short-term (7 h) Lim broth enrichment followed by FISH using oligonucleotide probes showed a high sensitivity and specificity, this protocol is therefore a highly accurate and relatively rapid method for the detection of S. agalactiae. Our analysis suggests that the use of DNA FISH to screen for S. agalactiae colonization in pregnant women may be considered in the absence of GBS culture availability

Use of a modified fluorescent in situ hybridization procedure to improve the identification of Streptococcus pneumoniae in blood cultures

Streptococcus pneumoniae is an important causative agent for bacteremia. Fluorescent in situ hybridization (FISH) is a helpful molecular technique for the rapid identification of S. pneumoniae in positive blood cultures. There are many reports concerning the application of an enzymatic treatment with lysozyme in the FISH procedure for partial cell wall digestion of S. pneumoniae. However, this study was aimed to test the FISH procedure without enzymatic treatment for the identification of S. pneumoniae in blood culture specimens. Seventy-seven positive blood culture specimens containing Gram-positive cocci were examined by both the conventional laboratory methods and FISH. Detection of S. pneumoniae was performed by two FISH procedures: one procedure was performed with an enzymatic treatment step and the other one was done without enzymatic treatment. In addition, the specimens were tested by the FISH procedure with enzymatic treatment to detect Streptococcus pyogenes and Enterococcus. The specificity of FISH in comparison with conventional culture methods was 100%. The sensitivity of the FISH procedure with enzymatic treatment for the detection of S. pneumoniae was 90%, whereas, the sensitivity of the FISH procedure without enzymatic treatment was 100%. In fact, by omission of enzymatic treatment, detection of S. pneumoniae was improved in 6 specimens. The results of the FISH and culture methods for the detection of S. pyogenes and Enterococcus were compatible. Altogether, FISH procedure without enzymatic treatment step seems to improve the detection of S. pneumoniae in some cases. Thus, for successful detection of S. pneumoniae, we suggest the application of both FISH procedures (the procedure with enzymatic treatment and the procedure without enzymatic treatment) for each blood culture specimen

Characterization and Pharmacological Activities of Jellyfish, Chrysaora hysoscella Captured in Bushehr Port, Iran

Background: Cutaneous reactions like pruritus and erythema are common in warm months of the year in Bushehr Port, Persian Gulf, Iran due to jellyfish envenomation. This study reports isolation of the Chrysaora hysoscella nematocysts and evaluating its pharmacological activities during a bloom in 2013. Methods: The venom of C. hysoscella captured in Jofre area in Bushehr port was analyzed. The electrophoretic profile was assessed by SDS-PAGE (12.5%) and the crude sample was analyzed using reverse phase HPLC. Caseinase activity was also determined. Results: After separation of tentacles and isolation of their nematocysts, three different major protein components were revealed at 72-250 kDa with SDS-PAGE, signifying the presence of peptides in its venom. Two major peaks at 8.62 and 11.23 min were observed in reverse phase HPLC of the crude venom denoting protease peptide structural identities. Caseinase activity of C. hysoscella's venom was extremely low as compared with other jellyfish venoms. Conclusion: This was the first report on the structural examination of jellyfish in Persian Gulf and may pave the way for determination and separation of destructive enzymes inducing cutaneous reactions in fishermen and swimmers