Search

ABSTRACT Rapid detection of carbapenemase-producing Enterobacteriaceae (CPE) is urgently needed to prevent their spread in healthcare settings. Here, we have evaluated the performance of the phenotypic methods for detection of carbapenemase production directly from bacterial cultures. A total of 99 clinical and rectal Enterobacteriaceae isolates were included (81 carrying known carbapenemase-encoding genes and 18 without carbapenemase production). All isolates were subjected to the five phenotypic tests including in-house Carba NP (iCarba NP), modified-Carba NP, E-Test MBL, modified Hodge test (MHT), and commercial combination disk test. Test results were read at different time points for iCarba NP and modified-Carba (1 min, 5 min, 15 min, 1 h and 2 h). The sensitivity and specificity of the iCarba NP were 78.87% and 100%, respectively, whereas those of the modified-Carba NP test were 95.06% and 94.44%, respectively. False-negative results were detected in four OXA-48 isolates with the use of modified-Carba NP, whereas one non-carbapenemase isolate had false-positive results. The sensitivity/specificity was 91.30%/100% and 80.25%/83.33% for the E-Test MBL and MHT, respectively. The sensitivity and specificity of the aminophenylboronic acid synergy test were 100% and 97.94%, respectively, whereas those of the dipicolinic acid synergy test were 82.61% and 96.23%, respectively. Rapid, simple, and reliable methods are needed for laboratory detection of CPE isolates to improve the detection and surveillance of these clinically relevant pathogens in an epidemiological context. We conclude that the modified-Carba NP test can be one of the reliable tests for the prediction of carbapenemase-producing bacteria.IMPORTANCEThe emergence of carbapenem resistance among Gram-negative bacteria is a serious global health threat. Here, we investigate the performance of the five phenotypic assays against carbapenemase-producing and carbapenemase-non-producing Enterobacteriaceae. Accurate and rapid detection of CPE isolates is critically required for clinical management and treatment of infections caused by these organisms. Among the five evaluated phenotypic tests, the mCNP test presented the highest sensitivity (95.06%) and, therefore, can be considered the best test to be used as a screening phenotypic methodology.

Background: Helicobacter pylori (H. pylori) is a highly prevalent, serious and chronic infection. It been associated causally with a diverse spectrum of gastrointestinal disorders including chronic gastritis, peptic ulcer disease, gastric adenocarcinoma. We conducted a study to Evaluation of the role of breastfeeding and breast milk on the colonization of H. pylori in the gastrointestinal tract of 2-24 month old. Methods: This cross-sectional study was performed on 92 children referred to Ali Asghar Hospital of Iran University of Medical Sciences for two years (from July 2015 to June 2017). At first, a questionnaire was recorded by the neonatal specialist including demographic and clinical characteristics of the infants. Stool samples were taken from infants at 2, 6, 12, and 24 months of age. We used the H. pylori stool antigen test to detection infection in the selected group of children. H. pylori status was evaluated by an enzyme-linked immunosorbent assay (ELISA). Results: In the study of breastfeeding at 12 months of age, 51.1% were fed only dry milk and 28.3% were breastfed only. At 24 months, 22 infants (24%) were breastfed with supplemental feeding and 54 children (58.7%) were formula-fed only and 8 children (8.7%) were breastfed only. In our study, the prevalence of H. pylori in infants of Tehran, at 2, 6, 12, and 24 months, were 0%, 6.5%, 15.21%, and 34.4%, respectively. Of the 92 children studied, during the first month, 25 children (27.2%) only formula-fed and 49 children (53.3%) were breastfed only and (19.6%) 18 infants were breastfed with dry milk. The prevalence of H. pylori infection was 28.3%. The prevalence of H. pylori infection was 20% in the breastfeeding group and 44% in the infant dry milk feeding group. The prevalence of H. pylori antigen was greater than 12 IU/ml in infants 2, 6, 12, and 24 months of age, including 19.92 (20.6%), 19.92 (20.6%), 24.92 (26.1%) and 21.92 (22.8%), respectively. Conclusion: According to the findings of the article, breastfed children compared to formula-fed children were less infected by Helicobacter pylori.

The growth rate of the population aging is increasing worldwide. To assess antimicrobial susceptibility of extended-spectrum β-lactamase- (ESBL-) producing Klebsiella pneumoniae Isolated from Patients aging in Rasool Akram, Hospital, as well as to identify AmpC genes. 100 K. pneumoniae strain isolated from different clinical samples. Isolates resistant to oxyimino-cephalosporins and to cefoxitin evaluated to phenotypic ESBL production and to phenotypic AmpC production, respectively. Detection of resistance genes was then performed using primers specific for AmpC genes. Piperacillin/tazobactam and carbapenems remained the active β-lactam antibiotic against K. pneumoniae. ESBLs were detected among 40 (40%) of K. pneumoniae isolates. CMY-1 gene was detected in 34.3% of all AmpC-positive isolates, whereas CMY-2 and FOX genes were 14.2% and 28.6%, respectively. The consumption of Carbapenem family drugs is high in Iranian hospitals which are used as a first line of treatment without antibiotic susceptibility testing. Therefore, increase in antibiotic resistance to this family drugs is unavoidable in the near future. Therefore, it is necessary to take the necessary measures to modify the administration and use of antibiotics.

Introduction: Pertussis or whooping cough is one of the vaccine preventable diseases. The purpose of this study was to evaluate the seroepidemiology of pertussis in two groups of children (i.e. under 2 months and 2-12 months old) who had been admitted to Tehran Children Hospital. Methods: Sampling from the children was done along with completing a questionnaire including demographic information, clinical symptoms and the history of the parents coughing. The levels of IgG-Ptx antibody were then measured using the children's sera. Results: Overall, 10.8% of the children were not immune, 78.3% were immune, and 10.9% had recent pertussis infections. Moreover, 19.4% of the female and 13.1% of the male subjects had the infection. In the age group less than two months, 16.6% were infected. The likelihood of new infection among the children less than 2 months old was 1.2 times higher than the control group (P < 0.004). Fifty percent of the children who were diagnosed with cyanosis in their clinical examinations had a recent infection (P

Background Helicobacter pylori (H. pylori) is a bacterium resides in the human stomach which is associated with gastroduodenal diseases. We investigate the prevalence of cagA, vacA, oipA, cagE1, cagE2 and dupA genotypes in H. pylori isolated from patients with Gastric ulcer, duodenal ulcer, and Gastric Cancer. Methods Collected 74 samples from the Gastroenterology Unit of the Rasool Akram Hospital were included in this study. Gastric disorders were identified by endoscopy .gastric cancer was further confirmed by histopathology. H. pylori were detected by the urease test. Subsequently, DNA was extracted from gastric tissue of the subjects with the CLO-test yielded positive results. Results In general, 74 patients with a mean age of 53.45 years (Range 22 to 86 years old), including 45 men and 29 women, were studied. Among 74 H. pylori-positive patients, 70 (94.5%) patients were positive for the cagA gene. About 95.8% (23/24) of the patients with gastric carcinoma were dupA positive and VacA gene (91.8%). The oipA genotype was detected in 71 (96%) of H.pylori positive samples. This gene was more common in patients with gastritis rather than cancer group. Also, 97.2% of 74 H. pylori isolates were cagE2-positive. In 25 patients with PUD, the occurrence percent of cagA+/VacA+, cagA+/Vac- , cagA- /VacA+ and cagA- /VaxA- genotypes were found 80%, 12%, 4.2% and 4.2 respectively. Conclusion The results of the present study suggest that a high prevalence of virulent factors could contribute to the risk of developing gastroduodenal diseases.

Background and Objectives: Despite widespread vaccination programs against pertussis, there has been a worldwide resurgence of the disease in recent years. We aimed to investigate protein composition of outer membrane vesicles (OMV) of Bordetella pertussis (Bp) and to evaluate the immunogenicity of OMV antigens both in the vaccine and the dominant wild type strains in Iran. Materials and Methods: The OMV were purified from both vaccine and wild type strains. The immunoreactivity of the OMVs was investigated by exposing sera taken from the patients and the vaccinated infants. The protein profiles of OMVs were compared using two-dimensional electrophoresis. The LC-MS/MS was used to analyse and identify differentially expressed protein spots. Results: The two type strains showed differences in their 2D gel protein profile. Further analysis of selected proteins from the dominant Iranian strains using LC-MS/MS demonstrated that the identified proteins fell into different functional categories including (i) metabolism, (ii) membrane transport and secretion system, (iii) biosynthesis and degradation, (iv) adaption, adhesion, pathogenicity, conserved hypothetical and protection responses. Moreover, a number of immunogenic proteins were identified including Bp 2434 (serine protease) and Bp 1616 (putative DNA binding protein) from the vaccine and the wild type strains, respectively which could be considered as potential antigens for an OMV vaccine. Conclusion: OMV Bp could be considered as an alternative vaccine against pertussis, containing the bacterium’s protein antigens that can confer equal efficacy compared to a whole bacterial cell vaccine with advantages such as less side effects and lower costs than acellular pertussis vaccines.

Background: Sexually transmitted infections are the most common human infections that lead to severe complications. Mycoplasma genitalium (MG) and Ureaplasma urealyticum (UU) are common and important cause of genitourinary tract infections. MG is a member of genital mycoplasmas which is emerging as an important causative agent of sexually transmitted infections both in males and females. This study aimed to determine the prevalence of UU and MG in pregnant women and to assess the risk factors which may contribute to the predisposition of the individuals to the infection. Methods: In this cross-sectional study, The population of 210 pregnant women admitted to the Rasoul Akram Hospital in Tehran, were selected for the study using non-random sampling. The urine specimens were collected from 194 pregnant women from May to December, 2015. The samples were transferred to the Infectious Disease Research Center of Rasoul Akram Hospital under sterile condition. Samples were exposed to DNA extraction followed by multiplex polymerase chain reaction (PCR) to detect the infection. Data including sex, age, history of abortion, history of genitourinary tract infections were collected subsequently. Results: The prevalence of MG and UU infections in urine samples was 5.6%, 11.2%, respectively. The mean and standard deviation of the risk of UU was 2.08 (3.56-1.22) in women with a history of abortion and 0.70 (1.03-0.47) in women without a history of abortion. There was a significant relationship between the history of sexually transmitted diseases and the frequency of UU (P

Background: The genus Bordetella harbors 16 species; three of them are well-known for their high medical importance. The phylogenetic diversity of the genus is currently not very well investigated. Methods: In this study, 16S rRNA gene sequence of 16 type strains of the Bordetella species were analyzed. Also, phylogenies conducted on the same gene of 247 isolates of Bordetella species, comprising a wide physiological as well as ecological diversity and encompassing ex-type representatives of the 16 Bordetella species, were analyzed. Results: It was found that the phylogenetic diversity of the genus may be very different from that is currently assumed. Interestingly, the 16S rRNA gene signals could not resolve some species with promising bootstrap and posterior probability values as our phylogenies, using maximum likelihood and Bayesian inference methods, showed. Conclusion: Our results indicate a probable need for additional phylogenetic signals which can be provided by coding genes. Therefore, sequence data of ompA gene of Bordetella species, a critically significant genomic region in pathogenesis, was here analyzed, phylogenetically. This gene confirmed the tree topology and the phylogenetic species boundaries already revealed by the 16S rRNA gene, but showed a better discriminatory power which resolved Bordetella species with higher statistically significant values.

Background: Excessive use of broad-spectrum antibiotics in hospitals has led to the emergence of highly resistant strains of Pseudomonas aeruginosa. The main mechanism of resistance of this bacterium to fluoroquinolones and carbapenems are the modification of type II topoisomerases (DNA gyrase and topoisomerase IV) and alterations in the OprD porin, respectively. The aim of this study was to examine for the occurrence of mutations related to fluoroquinolone resistance of gyrA and parC genes and mutational inactivation of oprD gene of clinical isolates using DNA sequencing technique. Methods: A total of 60 P. aeruginosa isolates were collected from the hospitalized patients in the Intensive Care Units (ICUs) of Al-Zahra hospital located in Isfahan, Iran. The pattern of sensitivity to antibiotics was determined using CLSI disk diffusion and MIC methods. The assay was based on a DNA sequencing method using polymerase chain reaction (PCR) for amplification and sequencing of the selected genes. Results: The results show that replacement of Ile for Thr-83 in gyrA was the only replacement, while other substitutions not observed. No mutations were found in parC. The most frequent amino acid alterations were E185Q, P186G, and V189T, found in five resistance isolates, However, nucleotide insertions and deletions mutations not observed. Conclusion: Our study suggested that mutation of gyrA and oprD genes may play a minor role in fluoroquinolone and carbapenem resistance and other mechanisms may contribute to the fluoroquinolone and carbapenem resistance of P. aeruginosa.

Background: The main cause of toxic shock is TSST-1 toxin which is produced by S. aureus. Finding of TSST-1 toxin in burnt children is very important to prevent TSS and its consequences. Methods: The aim of this study was to investigate the presence of gene encoding TSST-1 toxin in wound specimens by PCR. In this case-control study, 90 children who were admitted to the burn unit, were divided in two groups of 45 patients, namely febrile (cases group) and non-febrile (control group). Samplings were done from the burn wounds and were tested by PCR with specific primers of tstH gene. Finally, all data including demographic characteristics, percentage of burnt surface severity and the PCR results were analyzed, statistically. Results: The positive PCR results indicated the expression of tstH gene in 37.7% of the febrile children and 11.1% of the non-febrile children with a statistically significant difference (p