Comparison of virulence factors between ESBL and non-ESBL producing Klebsiella pneumoniae isolates.

Background and Objectives: Klebsiella pneumoniae is an opportunistic pathogen responsible for causing nosocomial and community-acquired infections. Its pathogenicity is associated with a variety of virulence factors and antibiotic resistance. The aim of the present study was to compare virulence attributes between ESBL and non-ESBL producing isolates. Materials and Methods: A total of 113 K. pneumoniae including 56 ESBL and 57 non ESBL-producers were collected in Bushehr province, Iran, from November 2017 to February 2019. Enzymatic profile, hypermucoviscosity and biofilm formation were investigated phenotypically. In addition, the presence of rmpA, aerobactin, kfu, allS, mrkD, ybtS, entB, iutA, fimH, wabG, wcaG, K1 and K2 genes were detected by PCR and sequencing. Results: There was no statistically significant difference in enzymatic profile between ESBL and non-ESBL producers. The prevalence of the hypermocoviscosity was lower among ESBL compared to non-ESBL producers but the intensity of biofilm was higher in the ESBL producers. Among the virulence genes, K1, rmpA, iutA, and aero were observed only in non-ESBLs. Moreover, the carriage of allS, K, K2, rmpA, iutA and aero genes was higher in hypermucoviscous in comparison with non hypermucoviscous isolates. Conclusion: The identification of potentially pathogenic isolates plays an important role in preventing their spread as well as the success of their treatment.

Detection of plasmid-mediated AmpC ß-lactamases in Klebsiella pneumoniae clinical isolates from Bushehr province, Iran.

Background and Objectives: Plasmid-mediated AmpC producers are considered an increasing concern. The aim of this study was to investigate the prevalence of plasmid-mediated AmpC ß-lactamases (pAmpCs) in Klebsiella pneumoniae isolates. Materials and Methods: A total of 228 clinical isolates of K. pneumoniae were collected in Bushehr province, Iran, from December 2017 to February 2019. Cefoxitin disks were applied for screening AmpC-producing isolates. Furthermore, 3 phenotypic confirmatory tests including combine disk test (CDT), double disk synergy test (DDST) and modified three dimensional test (M3DT) were used. Finally, the presence of pAmpC genes was tested by multiplex PCR. Results: We identified 18 pAmpC-KP isolates among the 228 isolates (7.9%): 12 DHA (66.6%) and 6 CMY (33.3%). In the present study only 47% of cefoxitin-resistant isolates were pAmpC producers. The sensitivity of CDT, DDST, and M3DT was 89%, 67% and 100% and the specificity was 90%, 90% and 85%, respectively. In addition, M3DT displayed a higher rate of efficiency (92%) than CDT (89%) and DDST (79%) in detecting plasmid-meditated AmpC producers. Conclusion: DHA was the most prevalent pAmpC beta-lactamase in this study. DDST and CDT tests proved inefficient to detect two and six pAmpC producers, respectively, while M3DT represented the best overall performance.

Phenotypic and genotypic investigation of metallo-ß-lactamases in Pseudomonas aeruginosa clinical isolates in Bushehr, Iran.

Objectives: Production of metallo-ß-lactamases (MBLs) is an important mechanism of resistance to carbapenems. This study aimed to detect the MBL-producing Pseudomonas aeruginosa clinical isolates and to investigate the presence of bla VIM, bla IMP, bla SPM, bla NDM, bla GIM, bla AIM, and bla SIM genes in these isolates in Bushehr, Iran. Materials and Methods: A total of 169 P. aeruginosa clinical isolates were collected from three hospitals in Bushehr. The modified carbapenem inactivation method (mCIM) was used for the phenotypic detection of carbapenemase production. A combination disk test (CDT) was performed for the phenotypic detection of MBL production. To investigate the presence of bla VIM, bla IMP, bla SPM, bla NDM, bla GIM, bla AIM, and bla SIM genes, PCR and sequencing was carried out. Results: Based on the results of mCIM, 40 (23.7%) of 169 isolates were carbapenemase producers. CDT revealed that 26 (15.4%) isolates were MBL producers. bla IMP, bla NDM, and bla VIM genes were found in 18 (69.2%), 8 (30.8%), and 1 (3.8%) of the MBL-producing isolates, respectively. Coexistence of bla IMP and bla NDM was observed in 2 (7.7%) MBL-producing isolates. Among all 169 P. aeruginosa isolates, 23 (13.6%) harbored bla NDM, 18 (10.6%) carried bla IMP, and 1 (0.6%) carried the bla VIM gene. bla SPM, bla GIM, bla AIM, and bla SIM were not found in the present study. Conclusion: bla NDM, bla IMP, and bla VIM genes were detected in this study, which could be a warning sign about the prevalence of these genes among P. aeruginosa clinical isolates in our region. Proper monitoring and detection of MBL-producing isolates are essential steps to prevent the spread of these isolates.

Anti-leishmanial activity of Avicennia marina (Avicenniaceae family) leaves hydroalcoholic extract and its possible cellular mechanisms.

Natural products are the main source of potent antioxidants and anti-leishmanial agents. This study was aimed to evaluate Avicennia marina (Avicenniaceae family) extract inhibitory effect against Leishmania tropica by accessing apoptotic markers and arginase activity. The A. marina were extracted and phytochemical analysis conducted. The inhibitory effect of A. marina was evaluated on L. tropica promastigote and amastigote forms, compared to meglumine antimoniate (Glucantime, MA) as standard drug. The level of apoptosis, Reactive Oxygen Species (ROS) production and arginase activity was assessed in A. marina-treated cells compared to control group. Phytochemical screening of A. marina extract showed strong presence of tannins and saponins. We demonstrated the inhibitory effect of A. marina on promastigote stages in a dose dependent manner. Also, lower 50% inhibitory concentration (IC50) value of amastigotes was indicated in A. marina group compared with the standard group of Glucantime (60.57 ± 1.46 vs. 73.19 ± 10.12 µg/mL, respectively, P < 0.05). Besides, A. marina represented no cytotoxicity as the selectivity index (SI) was 10.7. Also, it showed the potential to induce early apoptosis of 46.5% in promastigotes at 125 µg/mL concentration. Significant reduction of arginase level was observed in both A. marina-treated cells and promastigotes. The promising results indicated higher effectiveness of A. marina in decreasing parasite growth, inducing apoptosis in promastigotes, increasing ROS production and decreasing arginase level. So, A. marina can be a native plant candidate for anti-leishmanial drug in tropical regions with cutaneous leishmaniasis due to L. tropica.

Coexistence of aminoglycoside resistance genes in CTX-M-producing isolates of Klebsiella pneumoniae in Bushehr province, Iran.

BACKGROUND AND OBJECTIVES: Increasing the rate of extended-spectrum ß-lactamase (ESBL)-producing Klebsiella pneumoniae has given rise to a major healthcare issue in clinical settings over the past few years. Treatment of these strains is hardly effective since the plasmid encoding ESBL may also carry other resistance genes including aminoglycosides. The current study aimed to evaluate the prevalence of ESBL-producing K. pneumoniae and investigate the coexistence of Cefoxitamase-Munich (bla CTX-M) with aminoglycoside-modifying enzyme (AME) genes, aac(3)IIa as well as aac(6')Ib, in CTX-M-producing K. pneumoniae isolated from patients in Bushehr province, Iran. MATERIALS AND METHODS: A total of 212 K. pneumoniae isolates were collected and confirmed using polymerase chain reaction (PCR) of the malate dehydrogenase gene. Isolates were screened for production of ESBL. Phenotypic confirmatory test was performed using combined disk test. The genes encoding CTX-M groups and AME genes, aac(3)IIa and aac(6')Ib, were investigated by PCR. RESULTS: The ESBL phenotype was detected in 56 (26.4%) K. pneumoniae isolates. Moreover, 83.9% of ESBL-producing isolates carried the genes for CTX-M type ß-lactamases, which were distributed into the two genetic groups of CTX-M-1 (97.8%)- and CTX-M-2 (2.1%)-related enzymes. Notably, among K. pneumoniae isolates containing the bla CTX-M gene, 68.08% of isolates harbored AME genes. In addition, the coexistence of bla CTX-M with aac(3)-IIa and aac(6')-Ib was observed in 46.8% of CTX-M-producing K. pneumoniae isolates. CONCLUSION: This study provides evidence of a high prevalence of AME genes in CTX-M-producing K. pneumoniae isolates; therefore, in the initial empirical treatment of infections caused by ESBL-KP in regions with such antibiotic resistance patterns, aminoglycoside combination therapy should be undertaken carefully.

Abundance, composition, and potential intake of microplastics in canned fish.

The existence of microplastics (MPs) in canned fish (tuna and mackerel) samples was investigated and their composition, possible sources and potential intake were assessed. Light and fluorescence microscopy were used for the quantification of potential MPs. Furthermore, micro-Raman microscopy, and scanning electron microscopy coupled with an energy dispersive X-ray were used to identify the polymer types and composition of MPs. The results showed that 80% of samples had at least one plastic particle and fibers were the most abundant shapes of MPs. Moreover, polyethylene terephthalate (32.8%) was the most common polymer type in canned fish samples. The fish, food additives, and contact materials during the cleaning and canning process are possible sources of MPs. Human intake estimation of MPs showed the possibility of plastics absorption by humans who consume canned fish several times/week. Hence, the results of this study showed the importance of MPs' guidelines for food safety and hygiene.

Molecular Identification of Species Caused Cutaneous Leishmaniasis in Southern Zone of Iran.

BACKGROUND: Leishmania major and Leishmania tropica are two main species causing cutaneous leishmaniasis (CL) in Iran. Recently, Crithidia spp. has also been reported in the wound of patients with CL. In this study, we determined the species causing CL in the southern of Iran and the role of Crithidia spp. in creating skin ulcers. METHODS: In this cross-sectional study from Apr to Sep 2016, 66 patients with CL referred to Diagnostic Lab of Leishmaniasis, Valfajr Health Center, Shiraz, Iran, were selected. After DNA extraction from the Giemsa stained smears, all samples were amplified in two separate steps using specific primers, firstly, to differentiate Leishmania species and then to identify Crithidia spp. RESULTS: Two species L. major and L. tropica were responsible for 60 and 6 cases, respectively. Moreover, in two patients, mixed infection with Crithidia was confirmed. In mix infection cases, the morphology of the cutaneous ulcers was not different from the wounds of other patients. CONCLUSION: Leishmania major is responsible for the most common CL in southern Iran. In addition, in two patients with L. major and L. tropica, mix infection with Crithidia was confirmed. The potential role of Crithidia as the main factor for CL and the probability of this parasite to have synergistic effects on Leishmania, as a hypothesis, requires more comprehensive researches on the ambiguity of this protozoon.

Detection of Acinetobacter spp. in Blood Cultures by an Improved Fluorescent in Situ Hybridization Assay.

Fluorescent in situ hybridization (FISH) allows rapid detection of microorganisms. We aimed (i) to evaluate the sensitivity and specificity of FISH for the detection of Acinetobacter spp. in blood culture specimens and (ii) to test the simultaneous application of two genus-specific probes labeled with the same fluorochrome to increase the fluorescent signal intensity and improve the detection of Acinetobacter spp. Three hundred and twenty blood culture specimens were tested via both the conventional laboratory methods and FISH to detect Acinetobacter spp. The specimens were examined separately with each genus-specific probe Aci and ACA, and also using a mixture of the both probes Aci and ACA. In all examinations, probe EUB338 was used accompanied by Aci and ACA. The specificity of FISH was 100% (97.5% confidence interval [CI] = 98.7% - 100%). The sensitivity of FISH by the use of probe Aci was 96.4% (95% CI = 81.7% - 99.9%), whereas, the sensitivity of this technique by the use of probe ACA as well as by the combination of both probes Aci and ACA was 100% (97.5% CI = 87.7% - 100%). Moreover, simultaneous hybridization by probes Aci and ACA increased the fluorescent signal of Acinetobacter spp. cells to 3+ in 13 specimens. In conclusion, FISH, particularly using a combination of Aci and ACA, is a highly accurate method for the detection of Acinetobacter spp. in blood cultures. Furthermore, simultaneous hybridization by the both probes Aci and ACA can increase the fluorescent signal intensity of Acinetobacter spp. cells in some blood culture specimens and facilitate the detection of these microorganisms.

Characterization of plastic debris and association of metals with microplastics in coastline sediment along the Persian Gulf.

This study reports number, size and color distribution, and metal contents of microplastics as well as adherent sediments along the Persian Gulf. Samples were collected from 9 stations in summer 2015 with a sampling time interval of 10 days. Plastic size of 2-5 mm, and ≤0.25 mm with 45 and 33% and white and colorless plastics with 62 and 33% had the highest abundance considering number per m2, respectively. In general, the majority of collected plastics (79%) were smaller than 5 mm (defined size for microplastics). The mean Al, Fe, Mn, Cd, Cr, Ni, Pb, Cu contents of plastic fragments were 115, 531, 32.2, 0.035, 0.915, 2.03, 4.59, and 3.6 µg g-1, respectively while the mean Al, Fe, Mn, Cd, Cr, Ni, Pb, Cu contents of sediments were 186, 3050, 127, 0.81, 5.01, 14.5, 48.6 and 5.43 µg g-1 respectively. There were significant differences between the abundance of plastic items as well as the all examined metal concentrations of microplastics and sediments at different sampling times. As there is no regular cleanup program in the studied areas, significant differences between plastic items number at different sampling times (with higher plastic items number at the first day of sampling) showed that a large number of plastic items may enter from beaches to the sea and become available to marine organisms.

Sensitivity to Antibiotics of Bacteria Exposed to Gamma Radiation Emitted from Hot Soils of the High Background Radiation Areas of Ramsar, Northern Iran.

BACKGROUND: Over the past several years our laboratories have investigated different aspects of the challenging issue of the alterations in bacterial susceptibility to antibiotics induced by physical stresses. OBJECTIVE: To explore the bacterial susceptibility to antibiotics in samples of Salmonella enterica subsp. enterica serovar Typhimurium (S. typhimurium), Staphylococcus aureus, and Klebsiella pneumoniae after exposure to gamma radiation emitted from the soil samples taken from the high background radiation areas of Ramsar, northern Iran. METHODS: Standard Kirby-Bauer test, which evaluates the size of the zone of inhibition as an indicator of the susceptibility of different bacteria to antibiotics, was used in this study. RESULTS: The maximum alteration of the diameter of inhibition zone was found for K. pneumoniae when tested for ciprofloxacin. In this case, the mean diameter of no growth zone in non-irradiated control samples of K. pneumoniae was 20.3 (SD 0.6) mm; it was 14.7 (SD 0.6) mm in irradiated samples. On the other hand, the minimum changes in the diameter of inhibition zone were found for S. typhimurium and S. aureus when these bacteria were tested for nitrofurantoin and cephalexin, respectively. CONCLUSION: Gamma rays were capable of making significant alterations in bacterial susceptibility to antibiotics. It can be hypothesized that high levels of natural background radiation can induce adaptive phenomena that help microorganisms better cope with lethal effects of antibiotics.

Prevalence and Trends of Transfusion-Transmissible Viral Infections among Blood Donors in South of Iran: An Eleven-Year Retrospective Study.

BACKGROUND: Blood transfusion is considered a potential risk factor for transmission of life-threatening viral infections, including HIV, HCV and HBV infections. This study was performed to find out the prevalence and trends of these infections among blood donors in Southern Iran. METHODS: The blood donor data recorded in twelve regional blood transfusion centers from 2004 to 2014 were analyzed in an anonymous way with respect to the results of serological screening for HBV, HCV, and HIV infections. Overall, 293454 donors were screened for viral infections. RESULTS: Most of the donors were male, married, aged between 20-40 years, educated, and regular donors. The overall seroprevalence rates of HBV, HCV and HIV were 0.15%, 0.1% and 0.004%, respectively. The highest seroprevalence was found for HBV, followed by HCV and HIV. These infections were more prevalent in male, low educated and first time donors. The highest HCV seroprevalence was observed among donors aged 20 to 40 years, while HBV seroprevalence increased with age. The seroprevalence rates of HBV and HCV from 2004 to 2014 showed significant decreasing trends from 0.460% to 0.060% (P < 0.001) and 0.329% to 0.045% (P < 0.001), respectively. Whereas HIV infection had a slight but not significant decline from 0.0173% in 2004 to 0.0028% in 2014 (P = 0.087). CONCLUSIONS: The decreasing trends of transfusion-transmissible viral infections in blood donations indicate that the attempts of IBTO were successful in improving the safety of the blood supply, since the prevalence rates of viral infections have been reduced to very low levels in blood donations over the years. However, still more effective techniques such as polymerase chain reaction (PCR) are needed to guarantee blood safety.

Cytokine Profiles and Cell Proliferation Responses to Truncated ORF2 Protein in Iranian Patients Recovered from Hepatitis E Infection.

Background. The aim of this study was to evaluate hepatitis E virus (HEV) specific cellular immune responses to truncated ORF2 protein in Iranian patients recovered from HEV infection. Information about HEV-specific immune responses could be useful in finding an effective way for development of HEV vaccine. Methods. A truncated form of HEV ORF2 protein containing amino acids 112-608 was used to stimulate peripheral blood mononuclear cells (PBMCs) separated from HEV-recovered and control groups. Finally, the levels of four cytokines, IFN-γ ELISPOT, and cell proliferative responses following stimulation with the truncated ORF2 protein were assessed in the both groups. Results. The truncated ORF2 protein was able to induce IFN-γ ELISPOT and cell proliferation responses and to produce significant amounts of IFN-γ and IL-12 cytokines, but low amounts of IL-10 and IL-4 cytokines in vitro. These responses were significantly higher in the recovered group compared to the control group. These results indicate the antigenic nature of the truncated ORF2 protein and production of T helper type 1 cytokines. Conclusion. The truncated ORF2 protein can effectively induce significant cellular immune responsesand can be introduced as a potential vaccine candidate. However, further studies are required to evaluate this protein in vivo.

Invitro Antibacterial Activity of the Prosopis Juliflora Seed Pods on Some Common Pathogens.

INTRODUCTION: Prosopis juliflora is probably the most widespread species of genus Prosopis and it is a good source of compounds that have been shown to be pharmacologically active. This plant has been used as a traditional treatment for several diseases. AIM: To investigate the in-vitro antibacterial activity of the P. juliflora seed pods from Bushehr, South West of Iran. MATERIALS AND METHODS: In the present study, the antibacterial activity of P. juliflora seed pods extract was tested against Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli and Pseudomonas aeruginosa. The minimum inhibitory concentration (MIC) of the extract was determined for each test microorganism. RESULTS: P. juliflora seed pods extract exhibited antibacterial activity against all four test organisms. The MIC of the extract was 0.312 mg/ml and 0.078 mg/ml for S. aureus and S. epidermidis, respectively and 1.25 mg/ml for both E.coli and P.aeruginosa. CONCLUSION: P. juliflora seed pods from Bushehr, South West of Iran could be an appropriate source of antibacterial compounds that makes it a promising candidate for further studies.

Phylogenetic groups of Escherichia coli strains from patients with urinary tract infection in Iran based on the new Clermont phylotyping method.

OBJECTIVES: In 2013, Clermont classified E. coli strains into eight phylogenetic groups using a new quadruplex PCR method. The aims of this study were to identify the phylogenetic groups of E. coli based on this method and to assess their antibiotic resistance patterns in Bushehr, Iran. METHODS: In this cross-sectional study, 140 E. coli isolates were subjected to phylogenetic typing by a quadruplex PCR method. Antimicrobial susceptibility testing was performed by disk diffusion method. RESULTS: Phylogenetic group B2 was most predominant (39.3%), followed by unknown (27.1%), E (9.3%), C and clade I (each 6.4%), B1 (5%), F and D (each 2.9%), and A (0.7%). The most common antibiotic resistance was related to amoxicillin (82.1%) and the least to meropenem (0.7%). 82.14% of isolates were multiple drug resistant (MDR). Antibiotic resistance was mainly detected in group B2 (50%). CONCLUSIONS: Our findings showed the high prevalence of MDR E. coli isolates with dominance of group B2. About 25% of E. coli isolates belong to the newly described phylogroups C, E, F, and clade I. Such studies need to be done also in other regions to provide greater understanding of the antibiotic resistance pattern and the prevalences of different phylogenetic groups.

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.

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.

Evaluation of antiviral activities of curcumin derivatives against HSV-1 in Vero cell line.

Antiviral drug resistance is one of the most common problems in medicine, and, therefore, finding new antiviral agents, especially from natural resources, seems to be necessary. This study was designed to assay the antiviral activity of curcumin and its new derivatives like gallium-curcumin and Cu-curcumin on replication of HSV-1 in cell culture. The research was performed as an in vitro study in which the antiviral activity of different concentrations of three substances including curcumin, Gallium-curcumin and Cu-curcumin were tested on HSV-1. The cytotoxicity of the tested compounds was also evaluated on the Vero cell line. The CC50 values for curcumin, gallium-curcumin and Cu-curcumin were 484.2 microg/mL, 255.8 microg/mL and 326.6 microg/mL, respectively, and the respective IC50 values 33.0 microg/mL, 13.9 microg/mL and 23.1 microg/mL. The calculated SI values were 14.6, 18.4 and 14.1, respectively. The results showed that curcumin and its new derivatives have remarkable antiviral effects on HSV-1 in cell culture.

Comparison of fluorescent in situ hybridization and histological method for the diagnosis of Helicobacter pylori in gastric biopsy samples.

BACKGROUND: The establishment of Helicobacter pylori in the stomach and duodenum is associated with gastritis, peptic ulcers, and gastric cancer. Application of suitable methods, including molecular techniques, for an accurate detection of H. pylori can lead to the administration of appropriate drugs and successful therapy. In this study, fluorescent in situ hybridization (FISH) was compared with histology for the diagnosis of H. pylori in gastric biopsy specimens. MATERIAL/METHODS: Flourescently labeled oligonucleotdie probes that target ribosomal RNA were utilized in the FISH procedure. Ninety-one gastric biopsy specimens were tested by FISH and by histology using hematoxylin-eosin (H-E) and Geimsa stains. Furthermore, clarithromycin resistance in 39 of the 91 specimens was examined by FISH. RESULTS: The sensitivity and specificity of FISH for the detection of H. pylori were 97.9% and 100%, respectively. Of the 39 samples that were tested for clarithromycin resistance, 19 were FISH positive for H. pylori, of which 15 and 4 specimens were infected with clarithromycin-susceptible and clarithromycin-resistant strains, respectively. There were coccoid forms of H. pylori in a few of the specimens. CONCLUSIONS: FISH is a highly sensitive and specific technique for the diagnosis of H. pylori infection. It can be a method of identification when a patient is infected with coccoid forms of H. pylori. The ability of FISH for determination of clarithromycin resistance is a considerable advantage of this method over histology.

Application of fluorescent in situ hybridization (FISH) for the detection of Helicobacter pylori.

BACKGROUND: Peptic ulceration following infection of the stomach with H. Pylori is a common disease. Accurate and rapid detection of the bacteria can lead to the implementation of appropriate treatment and recovery. Chronic infection of the gastric milieu with H. Pylori may lead to gastric carcinoma. Routine detection of this bacterium in peptic ulcer is based on the urease test and culture of peptic biopsies. Unfortunately, the sensitivity and specificity of both tests are not satisfying. Molecular techniques have been successfully applied for the rapid and accurate detection of bacterial agents in clinical samples. This study was undertaken to evaluate the sensitivity and specificity of fluorescent in situ hybridization (FISH) in the detection of H. Pylori in patients suffering from dyspepsia. MATERIAL/METHODS: One hundred gastric biopsy samples taken by endoscopy from the antrum and corpus of the stomach were tested by FISH and compared with the conventional culture method complemented by biochemical tests. RESULTS: FISH detected H. Pylori in 48 clinical samples, while the conventional method detected 42 samples. The sensitivity and specificity of FISH for the detection of H. Pylori were calculated as 98% and 100%, respectively. CONCLUSIONS: The findings of this study suggest that FISH is a highly suitable and rapid method for diagnosing H. Pylori. Especially when the samples are taken from the antrum and the corpus of the stomach, this technique potentially can be applied routinely for the detection of this bacterium in clinical samples.