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Papers by mona mohammadzadeh

Research paper thumbnail of Short Communication Biotyping, Capsular Typing, and Antibiotic Resistance Pattern of Haemophilus influenzae Strains in Iran

Research paper thumbnail of In the Clinical Samples Isolated from

Genotyping of Haemophilus influenzae type b strains and their incidence

Research paper thumbnail of アシネトバクター・バウマンニの臨床分離株に対するカルバペネムのin vitro活性の比較【Powered by NICT】

Journal of Applied Microbiology, 2016

Research paper thumbnail of 広範囲薬剤耐性アシネトバクター・バウマンニと残された治療選択肢の傾向:3年間にわたるイラン,テヘランにおける多施設研究【Powered by NICT】

Letters in Applied Microbiology, 2016

Research paper thumbnail of Clonal relatedness and resistance characteristics of OXA‐24 and ‐58 producing carbapenem‐resistantAcinetobacter baumanniiisolates in Tehran, Iran

Journal of Applied Microbiology, 2019

The present study was conducted to investigate the mechanism of carbapenem resistance and molecul... more The present study was conducted to investigate the mechanism of carbapenem resistance and molecular epidemiology of carbapenem-resistant Acinetobacter baumannii (CRAB) isolates collected from two nearby hospitals in Tehran, Iran. Methods and Results: A total of 180 CRAB isolates were enrolled in our study. Antimicrobial susceptibility testing was performed using disk diffusion and Epsilometer test (E-test). Detection of OXA-23,-24 and-58 was implemented for all isolates using PCR. Subsequently, isolates harboring OXA-24 and-58 were investigated for the presence of resistance determinants of Ambler class A, metallo-β-lactamases (MBLs), and Carbapenem-Hydrolyzing class D β-lactamases (CHDLs), ISAba1, and genetic relatedness between them was analyzed using pulsed-field gel electrophoresis (PFGE). All isolates were found to be resistant to imipenem with MIC ≥ 8 µg/ml and susceptible to Accepted Article This article is protected by copyright. All rights reserved. colistin MIC ≤ 1.5 µg/ml. A total of 60 percent of isolates had OXA-23. OXA-24 and-58 were detected in 31 out of 180 CRAB isolates. These chosen isolates were devoid of MBLs and bla SHV , bla CTX-M , bla VEB ESBL genes. PER determinant was detected in 38% of isolates as the most common ESBLs. Among these isolates, 51.6% had OXA-23 and ISAba1 was found to be upstream of OXA-23 and OXA-51 in 16 and 8 isolates, respectively. The band patterns produced by PFGE showed 9 clonal pulsotypes distribution between the two hospitals. Conclusion: Our findings showed that the refractory CRAB isolates were transmitted intra-and inter-hospital, particularly in ICU due to shortcomings in infection control surveillances. Significance and Impact of the Study: Carbapenem resistance is a substantial threat in the treatment of infections caused by A. baumannii due to limitation in therapeutic options.

Research paper thumbnail of Trend of extensively drug-resistantAcinetobacter baumanniiand the remaining therapeutic options: a multicenter study in Tehran, Iran over a 3-year period

Letters in Applied Microbiology, 2016

Significance and Impact of study: The high frequency of drug-resistant phenotypes including CRAB,... more Significance and Impact of study: The high frequency of drug-resistant phenotypes including CRAB, MDR, and XDR has been demonstrated in A. baumannii isolates tested here. As the antibiotic resistance pattern of isolates varies in different geographical regions, the current study can provide comprehensive information about the antibiotic resistance profile of A. baumannii isolates in Tehran. In addition, the resistance profiles could be effectively considered by clinicians to manage antibiotic therapy. This work also emphasizes on prudent use of antibiotics and the monitoring of antibiotic susceptibility trend and rate.

Research paper thumbnail of Antimicrobial-resistant Shigella infections from Iran: an overlooked problem?

Journal of Antimicrobial Chemotherapy, 2012

In this study, we wanted to assess the level of antimicrobial resistance, the presence of genes e... more In this study, we wanted to assess the level of antimicrobial resistance, the presence of genes encoding resistance to cephalosporins and plasmid-mediated quinolone resistance (PMQR), and genetic relatedness among Shigella isolates obtained from Iranian patients. Methods: A total of 44 Shigella isolates were collected from Iranian patients admitted to Milad Hospital, Tehran, Iran, during 2008-10. Of these, 37 were serotyped and characterized by MIC determination. A subset of eight suspected extended-spectrum b-lactamase (ESBL) producers (six Shigella sonnei phase II and two Shigella flexneri type 1b) were examined for the presence of genes encoding cephalosporin resistance. The presence of PMQR was assessed in one S. flexneri isolate exhibiting low-level resistance to ciprofloxacin and susceptibility to nalidixic acid. PFGE was performed on 25 S. sonnei phase II isolates. Results: Of the isolates, 25 (68%) were S. sonnei phase II, with 5 (14%) S. flexneri, 5 (14%) Shigella dysenteriae type 2, and 2 (5%) Shigella boydii type 2. Resistance to at least three classes of antimicrobials was detected in all species. The presence of bla CTX-M-15 and the AmpC b-lactamase producer bla CMY-2 was confirmed in five and one S. sonnei phase II isolates, respectively. One of the two S. flexneri type 1b that contained bla CTX-M-15 also harboured a qnrS1 gene. PFGE identified seven PFGE profiles; the main cluster included 15 of the strains, suggesting low genetic diversity between isolates or the presence of an endemic clone in Iran. Conclusions: This is the first known description of ESBL-producing and AmpC b-lactamase-producing Shigella and of PMQR Shigella in Iran. The emergence of CTX-15, CMY-2 and qnrS1 genes may compromise the treatment of shigellosis. Strategies to minimize the spread of ESBL-producing and AmpC-b-lactamase-producing Shigella should be implemented.

Research paper thumbnail of Prevalence of Chlamydia trachomatis infections in symptomatic women by polymerase chain reaction (PCR) immunofluorescence and Giemsa stain

African Journal of Biotechnology, Jul 11, 2011

Chlamydia trachomatis is a ubiquitous human pathogen that is responsible for the most prevalent b... more Chlamydia trachomatis is a ubiquitous human pathogen that is responsible for the most prevalent bacterial sexually transmitted disease worldwide. Studies show that polymerase chain reaction (PCR) is more sensitive than cellular culture for detection of C. trachomatis infections. The aim of this study is to compare different laboratory methods, including Giemsa staining, direct immunofluorescence assay (DFA) and PCR for detection of C. trachomatis in women with urethral symptoms. In this study, 130 women with urethral symptoms admitted in the gynecology clinic, were used and specimens were obtained with endocervical swab for Giemsa staining, DFA and PCR. All the cases underwent these three techniques. Demographic data and the medical history of patients were obtained by direct interview; however, the mean age of cases was 33.8±9.06. Clinical symptoms included abnormal vaginal discharge in 101 cases (77.7%), spotting in 14 cases (10.8%), dysmenorrheal in 7 cases (5.4%), irritation in 6 cases (4.6%) and dysuria in 2 cases (1.5%). In DFA technique, 5 cases (3.8%) were positive and 3 (2.3%) were suspicious, while in the PCR technique, 6 cases (4.6%) were positive for C. trachomatis. However, 3 suspicious cases with DFA were negative in PCR. There was no positive case for C. trachomatis in Giemsa staining. In conclusion, C. trachomatis was not frequent in this study and it can be concluded that this infection was not a major hygienic problem in the same populations that were previously studied. Consequently, the causes that necessitate monogamy could be related to religious causes. Frequency of Chlamydia detection of DFA and PCR was same in the two groups. Nonetheless, Giemsa staining is not a reliable method for evaluating C. trachomatis.

Research paper thumbnail of Biotyping, Capsular Typing, and Antibiotic Resistance Pattern of Haemophilus influenzae Strains in Iran

Japanese Journal of Infectious Diseases

The aim of this study was to determine the capsular types of Haemophilus influenzae isolated from... more The aim of this study was to determine the capsular types of Haemophilus influenzae isolated from clinical specimens by slide agglutination serotyping (SAST) and PCR capsule typing methods. All the isolates were biotyped and their antibiotic resistance patterns also determined. Thirteen isolates of serotype b, 2 of serotype e, 4 of serotype f, and 19 nontypeable (NT) isolates were identified by SAST method in 38 H. influenzae culture-positive samples. Capsule typing by PCR increased the proportion of all invasive cases from 34.2z (by SAST) to 60.5z, and 6 culture-negative samples were identified as invasive H. influenzae (Hib) by this method. The discrepancy rate between SAST and PCR results were 41z. Biotypes I, II, and III were the prevalent biotypes whereas biotypes VI and VII were not found. The majority of capsule type b belonged to biotype II. The isolates were resistant to cotrimoxazole (47.1z) and ampicillin (43.6z). Multidrug resistance was observed in 7 of the isolates.

Research paper thumbnail of Construction and evaluation of a whole-cell pneumococcal vaccine candidate

Journal of Applied Microbiology

Pneumococcal infections are a major public health problem, especially in developing countries, an... more Pneumococcal infections are a major public health problem, especially in developing countries, and the current pneumococcal vaccines do not cover all pathogenic strains. New, more economical serotype‐independent vaccines based on species‐common protein antigens are being pursued. The pneumococcal whole‐cell vaccine which is based on noncapsular antigens common to all strains induces serotype‐independent immunity. In the present study, we developed a new candidate for a whole‐cell pneumococcal vaccine in which two important virulence factors, the capsule and pneumolysin, were deleted.

Research paper thumbnail of Recent approaches in whole cell pneumococcal vaccine development: a review study

Iranian Journal of Microbiology, 2017

Despite the availability of relatively effective vaccines, Streptococcus pneumoniae still causes ... more Despite the availability of relatively effective vaccines, Streptococcus pneumoniae still causes widespread morbidity and mortality. Current vaccines contain free polysaccharides or protein-polysaccharide conjugates, but do not induce protection against serotypes that are not included in the vaccines. Therefore, developing alternative vaccines is of high priority and importance. Several investigators have identified protective antigens common to pneumococci of many or all serotypes. Malley et al. in their study, have recommended unencapsulated whole cells, as an alternative vaccine, a number of such antigens unoccluded by capsule were presented in a native configuration in 2001. This review aimed at presenting this candidate of pneumococcal vaccine and results in an animal model.

Research paper thumbnail of Evaluation of Drug Resistance Frequency Among Entrococci Faecium and E. Faecalis Strains and Detection of Vana/B Genes in Vancomycin Resistance Isolated by PCR Method in Ilam and Kermanshah Hospitals

Iranian Journal of Medical Microbiology, 2011

Research paper thumbnail of Identification of Extended Spectrum Beta-lactamase producing Klebsiella pneumoniae isolated from Intensive Care Unit (ICU) patients in three hospitals in Tehran

of Study: Multiple drug resistance has significantly increased in recent years. The aim of our st... more of Study: Multiple drug resistance has significantly increased in recent years. The aim of our study was to determine the antibiotic susceptibility of Klebsiella pneumoniae isolated from Intensive Care Unit (ICU) patients in three hospitals in Tehran, Iran. Methods: A total of 116 K. pneumoniae isolates were collected from different clinical samples of patients admitted to the ICUs of three hospitals in Tehran, Iran between March and December 2011. Most strains were isolated from tracheal secretions (75%), and urine (16%). Identification was carried out based on biochemical tests and the PCR method to detect the 16S-23S internal transcribed spacer unit of K. pneumoniae subsp. pneumoniae. Susceptibility of isolates to 14 different antibiotic disks was determined using agar disk diffusion method. The combination disk method was used for phenotypic detection of the ESBL- producing isolates. Results: All of the 116 isolates (except one isolate) were susceptible to imipenem. Most of the ...

Research paper thumbnail of Frequency of Extended Spectrum Beta Lactamases, CTX-M Type in Clinical Salmonella SPP Isolated in Tehran, Iran

Backgr Backgr Backgr Backgr Background: ound: ound: ound: ound: The spectrum of bacteria causing ... more Backgr Backgr Backgr Backgr Background: ound: ound: ound: ound: The spectrum of bacteria causing urinary tract infection (UTI) and their antibiotic sensitivity pattern is not uniform. Escherichia coli and Klebsiella sp. are two common organisms responsible for UTI throughout the world. The incidence of UTI due to infection with extended-spectrum beta-lactamase (ESBL) producing organisms are increasing. This study was aimed to describe the frequency of ESBL positive organisms causing UTI and their antibiotic sensitivity pattern.

Research paper thumbnail of Microbiologic assessment of non-surgical traumatic wound infections and surgical site infections in hospitalized patients

Archives of Clinical Infectious Diseases, 2010

Background: Surgical site infections (SSIs) are the most common nosocomial infections in surgical... more Background: Surgical site infections (SSIs) are the most common nosocomial infections in surgical patients. Depending on the source of a traumatic wound, particular pathogens are expected to be present while their prevalence varies in different conditions. This study focused on determination of microorganisms in traumatic wound infection and the frequency of Staphylococcus aureus and other organisms in SSIs. Patients and methods: A total of 116 patients were studied among whom 86 patients (18 females and 68 males) underwent microbiological assessment for non-surgical wound infections and 30 patients (all were males) had SSIs. Specimens were cultured on blood agar, MacConkey agar, and chocolate agar while direct examination and gramstaining were also achieved for each sample. Results: Staphylococcus aureus (20.9%) was the most commonly isolated organism among non-surgical traumatic wound infections, however, Proteus mirabilis, Salmonella Arizona and streptococcus group A were less co...

Research paper thumbnail of The prevalence of nosocomial infections caused by Enterobacter cloacae and antibiotic resistant patterns in samples isolated from patients in two hospitals in Tehran

Tehran University Medical Journal TUMS Publications, 2012

Background: The increasing use of β-lactam antibiotics in clinics for the treatment of different ... more Background: The increasing use of β-lactam antibiotics in clinics for the treatment of different bacterial infections since early 1980s has led to increased rates of resistant bacteria isolated from patients. One of the problems in the treatment of nosocomial infections is related to resistant bacteria such as Enterobacter cloacae due to cross resistance through extended-spectrum beta-lactamase production. The aim of this study was to determine the prevalence of extended-spectrum beta-lactamase producing E. cloacae from different clinical specimens collected from hospitalized patients. Methods: In the present study, 101 E. cloacae confirmed by standard specific microbiologic tests were collected from different specimens in Milad and Motahri hospitals in Tehran, Iran during February 2010 and September 2011. Antibiotic susceptibility tests were conducted according to the process recommended by the Clinical and Laboratory Standards Institute for 13 antibiotics of choice. Extended- spec...

Research paper thumbnail of Surveying the Frequency of Non-Fermentative Gram-Negative Bacilli in the Environment and Equipment of Tehran Selected Hospitals

Background: Non-fermentative, gram-negative bacilli (NFGNB) have emerged as a factor of nosocomia... more Background: Non-fermentative, gram-negative bacilli (NFGNB) have emerged as a factor of nosocomial infections and mortal epidemics . Hospital environment is one of the most important sources of NFGNB`s colonization and diffusion. This study is aimed to assess the frequency of NFGNB in various wards of selected hospitals of Tehran. Materials & Methods: 469 samples were randomly selected from various wards from two hospitals during a period of 11 weeks. All isolations had been identified using standard microbiological, biochemical and phenotypic tests. The data were analyzed by SPSS software (version 11.5). Results: Fifty three specimens were positive for NFGNB. Stenotrophomonas maltophilia and Burkholderia cepacia complex were found as predominant bacteria in hospital I(28%) and II (28.6%).The highest rate of NFGNB isolated from surfaces was 60.3% .The pediatric ward was identified as the most contaminated ward (50%). Conclusion: Several genus of NFGNB are found in hospitals. Therefo...

Research paper thumbnail of Antimicrobial resistance in Streptococcus pneumoniae isolates from invasive pneumococcal infections in Iran

Journal of global antimicrobial resistance, 2019

Research paper thumbnail of Efficacy of whole-cell pneumococcal vaccine in mice: A systematic review and meta-analysis

Microbial Pathogenesis

BACKGROUND Despite the fact that pneumococcal conjugate vaccines (PCVs) have significantly reduce... more BACKGROUND Despite the fact that pneumococcal conjugate vaccines (PCVs) have significantly reduced the rate of invasive pneumococcal diseases through the use of vaccine serotypes, infection with Streptococcus pneumoniae remains a major public health hazard. Serotype-independent vaccines that are economically viable species of common protein antigens such as whole-cell vaccines (WCVs) are needed. Considering the ongoing debate about the effectiveness of WCVs, a systematic literature review and meta-analysis was carried out to determine the efficacy of WCVs against colonization in mice. MATERIAL AND METHODS A systematic review was undertaken of published studies on the protection (colonized/uncolonized) of whole cell pneumococcal vaccine in mice. The search terms used were "whole cell vaccine" and "Streptococcus pneumoniae" in PubMed, Google Scholar, Embase, Web of Science and Scopus engines. Data was extracted from original publications and a meta-analysis was performed on studies divided into sub-groups by the number of inoculations, type of sample, type of adjuvant, time of sampling, design of study and quality of study. RESULTS Ten eligible articles published from 2000 to 2016 were included in this review. The meta-analysis was performed on eight out of 10 studies and demonstrated that the estimated pooled risk ratios (RRs) for comparison of colonization between the vaccinated and unvaccinated mice for outcomes 1 and 2 were 0.18 and 0.24, respectively. Lower RRs were observed in sub-groups that were inoculated with vaccines three times, those using cholera toxin (CT) adjuvants and those obtained as tracheal specimens from the mice. CONCLUSIONS The best protocol for use of a WCV is its application with CT adjuvant administered intranasally in three inoculations at doses of 10⁸ CFU. Further studies performed under similar conditions to obtain accurate results on the effectiveness of this vaccine are recommended.

Research paper thumbnail of Clonal relatedness and biofilm formation of OXA-23-producing carbapenem resistant Acinetobacter baumannii isolates from hospital environment

Microbial pathogenesis, 2016

Carbapenem-resistant Acinetobacter baumannii (CRAB) is a serious threat for hospitalized patients... more Carbapenem-resistant Acinetobacter baumannii (CRAB) is a serious threat for hospitalized patients and it can survive for long periods in hospital settings, particularly on inanimate surfaces. The environment occupied by these resistant and resilient isolates may act as a reservoir for cross-colonization and outbreaks. Here, we aimed to determine the distribution of CRAB in the hospital environment and to characterize their clonal relatedness, susceptibility profile, carriage of blaOXA genes, and biofilm formation. A total of 1080 samples were collected from various environmental surfaces and equipment of two referral hospitals in Tehran, Iran. The A. baumannii isolates were subjected to gyrB multiplex PCR, antibiotic susceptibility testing, biofilm formation assay, pulsed field gel electrophoresis (PFGE), and multiplex PCR for blaOXA-58, blaOXA-24, and blaOXA-23 genes. Eighteen Acinetobacter spp. were isolated; 8 were identified as A. baumannii and 10 as A. lwoffii. Five of A. bauma...

Research paper thumbnail of Short Communication Biotyping, Capsular Typing, and Antibiotic Resistance Pattern of Haemophilus influenzae Strains in Iran

Research paper thumbnail of In the Clinical Samples Isolated from

Genotyping of Haemophilus influenzae type b strains and their incidence

Research paper thumbnail of アシネトバクター・バウマンニの臨床分離株に対するカルバペネムのin vitro活性の比較【Powered by NICT】

Journal of Applied Microbiology, 2016

Research paper thumbnail of 広範囲薬剤耐性アシネトバクター・バウマンニと残された治療選択肢の傾向:3年間にわたるイラン,テヘランにおける多施設研究【Powered by NICT】

Letters in Applied Microbiology, 2016

Research paper thumbnail of Clonal relatedness and resistance characteristics of OXA‐24 and ‐58 producing carbapenem‐resistantAcinetobacter baumanniiisolates in Tehran, Iran

Journal of Applied Microbiology, 2019

The present study was conducted to investigate the mechanism of carbapenem resistance and molecul... more The present study was conducted to investigate the mechanism of carbapenem resistance and molecular epidemiology of carbapenem-resistant Acinetobacter baumannii (CRAB) isolates collected from two nearby hospitals in Tehran, Iran. Methods and Results: A total of 180 CRAB isolates were enrolled in our study. Antimicrobial susceptibility testing was performed using disk diffusion and Epsilometer test (E-test). Detection of OXA-23,-24 and-58 was implemented for all isolates using PCR. Subsequently, isolates harboring OXA-24 and-58 were investigated for the presence of resistance determinants of Ambler class A, metallo-β-lactamases (MBLs), and Carbapenem-Hydrolyzing class D β-lactamases (CHDLs), ISAba1, and genetic relatedness between them was analyzed using pulsed-field gel electrophoresis (PFGE). All isolates were found to be resistant to imipenem with MIC ≥ 8 µg/ml and susceptible to Accepted Article This article is protected by copyright. All rights reserved. colistin MIC ≤ 1.5 µg/ml. A total of 60 percent of isolates had OXA-23. OXA-24 and-58 were detected in 31 out of 180 CRAB isolates. These chosen isolates were devoid of MBLs and bla SHV , bla CTX-M , bla VEB ESBL genes. PER determinant was detected in 38% of isolates as the most common ESBLs. Among these isolates, 51.6% had OXA-23 and ISAba1 was found to be upstream of OXA-23 and OXA-51 in 16 and 8 isolates, respectively. The band patterns produced by PFGE showed 9 clonal pulsotypes distribution between the two hospitals. Conclusion: Our findings showed that the refractory CRAB isolates were transmitted intra-and inter-hospital, particularly in ICU due to shortcomings in infection control surveillances. Significance and Impact of the Study: Carbapenem resistance is a substantial threat in the treatment of infections caused by A. baumannii due to limitation in therapeutic options.

Research paper thumbnail of Trend of extensively drug-resistantAcinetobacter baumanniiand the remaining therapeutic options: a multicenter study in Tehran, Iran over a 3-year period

Letters in Applied Microbiology, 2016

Significance and Impact of study: The high frequency of drug-resistant phenotypes including CRAB,... more Significance and Impact of study: The high frequency of drug-resistant phenotypes including CRAB, MDR, and XDR has been demonstrated in A. baumannii isolates tested here. As the antibiotic resistance pattern of isolates varies in different geographical regions, the current study can provide comprehensive information about the antibiotic resistance profile of A. baumannii isolates in Tehran. In addition, the resistance profiles could be effectively considered by clinicians to manage antibiotic therapy. This work also emphasizes on prudent use of antibiotics and the monitoring of antibiotic susceptibility trend and rate.

Research paper thumbnail of Antimicrobial-resistant Shigella infections from Iran: an overlooked problem?

Journal of Antimicrobial Chemotherapy, 2012

In this study, we wanted to assess the level of antimicrobial resistance, the presence of genes e... more In this study, we wanted to assess the level of antimicrobial resistance, the presence of genes encoding resistance to cephalosporins and plasmid-mediated quinolone resistance (PMQR), and genetic relatedness among Shigella isolates obtained from Iranian patients. Methods: A total of 44 Shigella isolates were collected from Iranian patients admitted to Milad Hospital, Tehran, Iran, during 2008-10. Of these, 37 were serotyped and characterized by MIC determination. A subset of eight suspected extended-spectrum b-lactamase (ESBL) producers (six Shigella sonnei phase II and two Shigella flexneri type 1b) were examined for the presence of genes encoding cephalosporin resistance. The presence of PMQR was assessed in one S. flexneri isolate exhibiting low-level resistance to ciprofloxacin and susceptibility to nalidixic acid. PFGE was performed on 25 S. sonnei phase II isolates. Results: Of the isolates, 25 (68%) were S. sonnei phase II, with 5 (14%) S. flexneri, 5 (14%) Shigella dysenteriae type 2, and 2 (5%) Shigella boydii type 2. Resistance to at least three classes of antimicrobials was detected in all species. The presence of bla CTX-M-15 and the AmpC b-lactamase producer bla CMY-2 was confirmed in five and one S. sonnei phase II isolates, respectively. One of the two S. flexneri type 1b that contained bla CTX-M-15 also harboured a qnrS1 gene. PFGE identified seven PFGE profiles; the main cluster included 15 of the strains, suggesting low genetic diversity between isolates or the presence of an endemic clone in Iran. Conclusions: This is the first known description of ESBL-producing and AmpC b-lactamase-producing Shigella and of PMQR Shigella in Iran. The emergence of CTX-15, CMY-2 and qnrS1 genes may compromise the treatment of shigellosis. Strategies to minimize the spread of ESBL-producing and AmpC-b-lactamase-producing Shigella should be implemented.

Research paper thumbnail of Prevalence of Chlamydia trachomatis infections in symptomatic women by polymerase chain reaction (PCR) immunofluorescence and Giemsa stain

African Journal of Biotechnology, Jul 11, 2011

Chlamydia trachomatis is a ubiquitous human pathogen that is responsible for the most prevalent b... more Chlamydia trachomatis is a ubiquitous human pathogen that is responsible for the most prevalent bacterial sexually transmitted disease worldwide. Studies show that polymerase chain reaction (PCR) is more sensitive than cellular culture for detection of C. trachomatis infections. The aim of this study is to compare different laboratory methods, including Giemsa staining, direct immunofluorescence assay (DFA) and PCR for detection of C. trachomatis in women with urethral symptoms. In this study, 130 women with urethral symptoms admitted in the gynecology clinic, were used and specimens were obtained with endocervical swab for Giemsa staining, DFA and PCR. All the cases underwent these three techniques. Demographic data and the medical history of patients were obtained by direct interview; however, the mean age of cases was 33.8±9.06. Clinical symptoms included abnormal vaginal discharge in 101 cases (77.7%), spotting in 14 cases (10.8%), dysmenorrheal in 7 cases (5.4%), irritation in 6 cases (4.6%) and dysuria in 2 cases (1.5%). In DFA technique, 5 cases (3.8%) were positive and 3 (2.3%) were suspicious, while in the PCR technique, 6 cases (4.6%) were positive for C. trachomatis. However, 3 suspicious cases with DFA were negative in PCR. There was no positive case for C. trachomatis in Giemsa staining. In conclusion, C. trachomatis was not frequent in this study and it can be concluded that this infection was not a major hygienic problem in the same populations that were previously studied. Consequently, the causes that necessitate monogamy could be related to religious causes. Frequency of Chlamydia detection of DFA and PCR was same in the two groups. Nonetheless, Giemsa staining is not a reliable method for evaluating C. trachomatis.

Research paper thumbnail of Biotyping, Capsular Typing, and Antibiotic Resistance Pattern of Haemophilus influenzae Strains in Iran

Japanese Journal of Infectious Diseases

The aim of this study was to determine the capsular types of Haemophilus influenzae isolated from... more The aim of this study was to determine the capsular types of Haemophilus influenzae isolated from clinical specimens by slide agglutination serotyping (SAST) and PCR capsule typing methods. All the isolates were biotyped and their antibiotic resistance patterns also determined. Thirteen isolates of serotype b, 2 of serotype e, 4 of serotype f, and 19 nontypeable (NT) isolates were identified by SAST method in 38 H. influenzae culture-positive samples. Capsule typing by PCR increased the proportion of all invasive cases from 34.2z (by SAST) to 60.5z, and 6 culture-negative samples were identified as invasive H. influenzae (Hib) by this method. The discrepancy rate between SAST and PCR results were 41z. Biotypes I, II, and III were the prevalent biotypes whereas biotypes VI and VII were not found. The majority of capsule type b belonged to biotype II. The isolates were resistant to cotrimoxazole (47.1z) and ampicillin (43.6z). Multidrug resistance was observed in 7 of the isolates.

Research paper thumbnail of Construction and evaluation of a whole-cell pneumococcal vaccine candidate

Journal of Applied Microbiology

Pneumococcal infections are a major public health problem, especially in developing countries, an... more Pneumococcal infections are a major public health problem, especially in developing countries, and the current pneumococcal vaccines do not cover all pathogenic strains. New, more economical serotype‐independent vaccines based on species‐common protein antigens are being pursued. The pneumococcal whole‐cell vaccine which is based on noncapsular antigens common to all strains induces serotype‐independent immunity. In the present study, we developed a new candidate for a whole‐cell pneumococcal vaccine in which two important virulence factors, the capsule and pneumolysin, were deleted.

Research paper thumbnail of Recent approaches in whole cell pneumococcal vaccine development: a review study

Iranian Journal of Microbiology, 2017

Despite the availability of relatively effective vaccines, Streptococcus pneumoniae still causes ... more Despite the availability of relatively effective vaccines, Streptococcus pneumoniae still causes widespread morbidity and mortality. Current vaccines contain free polysaccharides or protein-polysaccharide conjugates, but do not induce protection against serotypes that are not included in the vaccines. Therefore, developing alternative vaccines is of high priority and importance. Several investigators have identified protective antigens common to pneumococci of many or all serotypes. Malley et al. in their study, have recommended unencapsulated whole cells, as an alternative vaccine, a number of such antigens unoccluded by capsule were presented in a native configuration in 2001. This review aimed at presenting this candidate of pneumococcal vaccine and results in an animal model.

Research paper thumbnail of Evaluation of Drug Resistance Frequency Among Entrococci Faecium and E. Faecalis Strains and Detection of Vana/B Genes in Vancomycin Resistance Isolated by PCR Method in Ilam and Kermanshah Hospitals

Iranian Journal of Medical Microbiology, 2011

Research paper thumbnail of Identification of Extended Spectrum Beta-lactamase producing Klebsiella pneumoniae isolated from Intensive Care Unit (ICU) patients in three hospitals in Tehran

of Study: Multiple drug resistance has significantly increased in recent years. The aim of our st... more of Study: Multiple drug resistance has significantly increased in recent years. The aim of our study was to determine the antibiotic susceptibility of Klebsiella pneumoniae isolated from Intensive Care Unit (ICU) patients in three hospitals in Tehran, Iran. Methods: A total of 116 K. pneumoniae isolates were collected from different clinical samples of patients admitted to the ICUs of three hospitals in Tehran, Iran between March and December 2011. Most strains were isolated from tracheal secretions (75%), and urine (16%). Identification was carried out based on biochemical tests and the PCR method to detect the 16S-23S internal transcribed spacer unit of K. pneumoniae subsp. pneumoniae. Susceptibility of isolates to 14 different antibiotic disks was determined using agar disk diffusion method. The combination disk method was used for phenotypic detection of the ESBL- producing isolates. Results: All of the 116 isolates (except one isolate) were susceptible to imipenem. Most of the ...

Research paper thumbnail of Frequency of Extended Spectrum Beta Lactamases, CTX-M Type in Clinical Salmonella SPP Isolated in Tehran, Iran

Backgr Backgr Backgr Backgr Background: ound: ound: ound: ound: The spectrum of bacteria causing ... more Backgr Backgr Backgr Backgr Background: ound: ound: ound: ound: The spectrum of bacteria causing urinary tract infection (UTI) and their antibiotic sensitivity pattern is not uniform. Escherichia coli and Klebsiella sp. are two common organisms responsible for UTI throughout the world. The incidence of UTI due to infection with extended-spectrum beta-lactamase (ESBL) producing organisms are increasing. This study was aimed to describe the frequency of ESBL positive organisms causing UTI and their antibiotic sensitivity pattern.

Research paper thumbnail of Microbiologic assessment of non-surgical traumatic wound infections and surgical site infections in hospitalized patients

Archives of Clinical Infectious Diseases, 2010

Background: Surgical site infections (SSIs) are the most common nosocomial infections in surgical... more Background: Surgical site infections (SSIs) are the most common nosocomial infections in surgical patients. Depending on the source of a traumatic wound, particular pathogens are expected to be present while their prevalence varies in different conditions. This study focused on determination of microorganisms in traumatic wound infection and the frequency of Staphylococcus aureus and other organisms in SSIs. Patients and methods: A total of 116 patients were studied among whom 86 patients (18 females and 68 males) underwent microbiological assessment for non-surgical wound infections and 30 patients (all were males) had SSIs. Specimens were cultured on blood agar, MacConkey agar, and chocolate agar while direct examination and gramstaining were also achieved for each sample. Results: Staphylococcus aureus (20.9%) was the most commonly isolated organism among non-surgical traumatic wound infections, however, Proteus mirabilis, Salmonella Arizona and streptococcus group A were less co...

Research paper thumbnail of The prevalence of nosocomial infections caused by Enterobacter cloacae and antibiotic resistant patterns in samples isolated from patients in two hospitals in Tehran

Tehran University Medical Journal TUMS Publications, 2012

Background: The increasing use of β-lactam antibiotics in clinics for the treatment of different ... more Background: The increasing use of β-lactam antibiotics in clinics for the treatment of different bacterial infections since early 1980s has led to increased rates of resistant bacteria isolated from patients. One of the problems in the treatment of nosocomial infections is related to resistant bacteria such as Enterobacter cloacae due to cross resistance through extended-spectrum beta-lactamase production. The aim of this study was to determine the prevalence of extended-spectrum beta-lactamase producing E. cloacae from different clinical specimens collected from hospitalized patients. Methods: In the present study, 101 E. cloacae confirmed by standard specific microbiologic tests were collected from different specimens in Milad and Motahri hospitals in Tehran, Iran during February 2010 and September 2011. Antibiotic susceptibility tests were conducted according to the process recommended by the Clinical and Laboratory Standards Institute for 13 antibiotics of choice. Extended- spec...

Research paper thumbnail of Surveying the Frequency of Non-Fermentative Gram-Negative Bacilli in the Environment and Equipment of Tehran Selected Hospitals

Background: Non-fermentative, gram-negative bacilli (NFGNB) have emerged as a factor of nosocomia... more Background: Non-fermentative, gram-negative bacilli (NFGNB) have emerged as a factor of nosocomial infections and mortal epidemics . Hospital environment is one of the most important sources of NFGNB`s colonization and diffusion. This study is aimed to assess the frequency of NFGNB in various wards of selected hospitals of Tehran. Materials & Methods: 469 samples were randomly selected from various wards from two hospitals during a period of 11 weeks. All isolations had been identified using standard microbiological, biochemical and phenotypic tests. The data were analyzed by SPSS software (version 11.5). Results: Fifty three specimens were positive for NFGNB. Stenotrophomonas maltophilia and Burkholderia cepacia complex were found as predominant bacteria in hospital I(28%) and II (28.6%).The highest rate of NFGNB isolated from surfaces was 60.3% .The pediatric ward was identified as the most contaminated ward (50%). Conclusion: Several genus of NFGNB are found in hospitals. Therefo...

Research paper thumbnail of Antimicrobial resistance in Streptococcus pneumoniae isolates from invasive pneumococcal infections in Iran

Journal of global antimicrobial resistance, 2019

Research paper thumbnail of Efficacy of whole-cell pneumococcal vaccine in mice: A systematic review and meta-analysis

Microbial Pathogenesis

BACKGROUND Despite the fact that pneumococcal conjugate vaccines (PCVs) have significantly reduce... more BACKGROUND Despite the fact that pneumococcal conjugate vaccines (PCVs) have significantly reduced the rate of invasive pneumococcal diseases through the use of vaccine serotypes, infection with Streptococcus pneumoniae remains a major public health hazard. Serotype-independent vaccines that are economically viable species of common protein antigens such as whole-cell vaccines (WCVs) are needed. Considering the ongoing debate about the effectiveness of WCVs, a systematic literature review and meta-analysis was carried out to determine the efficacy of WCVs against colonization in mice. MATERIAL AND METHODS A systematic review was undertaken of published studies on the protection (colonized/uncolonized) of whole cell pneumococcal vaccine in mice. The search terms used were "whole cell vaccine" and "Streptococcus pneumoniae" in PubMed, Google Scholar, Embase, Web of Science and Scopus engines. Data was extracted from original publications and a meta-analysis was performed on studies divided into sub-groups by the number of inoculations, type of sample, type of adjuvant, time of sampling, design of study and quality of study. RESULTS Ten eligible articles published from 2000 to 2016 were included in this review. The meta-analysis was performed on eight out of 10 studies and demonstrated that the estimated pooled risk ratios (RRs) for comparison of colonization between the vaccinated and unvaccinated mice for outcomes 1 and 2 were 0.18 and 0.24, respectively. Lower RRs were observed in sub-groups that were inoculated with vaccines three times, those using cholera toxin (CT) adjuvants and those obtained as tracheal specimens from the mice. CONCLUSIONS The best protocol for use of a WCV is its application with CT adjuvant administered intranasally in three inoculations at doses of 10⁸ CFU. Further studies performed under similar conditions to obtain accurate results on the effectiveness of this vaccine are recommended.

Research paper thumbnail of Clonal relatedness and biofilm formation of OXA-23-producing carbapenem resistant Acinetobacter baumannii isolates from hospital environment

Microbial pathogenesis, 2016

Carbapenem-resistant Acinetobacter baumannii (CRAB) is a serious threat for hospitalized patients... more Carbapenem-resistant Acinetobacter baumannii (CRAB) is a serious threat for hospitalized patients and it can survive for long periods in hospital settings, particularly on inanimate surfaces. The environment occupied by these resistant and resilient isolates may act as a reservoir for cross-colonization and outbreaks. Here, we aimed to determine the distribution of CRAB in the hospital environment and to characterize their clonal relatedness, susceptibility profile, carriage of blaOXA genes, and biofilm formation. A total of 1080 samples were collected from various environmental surfaces and equipment of two referral hospitals in Tehran, Iran. The A. baumannii isolates were subjected to gyrB multiplex PCR, antibiotic susceptibility testing, biofilm formation assay, pulsed field gel electrophoresis (PFGE), and multiplex PCR for blaOXA-58, blaOXA-24, and blaOXA-23 genes. Eighteen Acinetobacter spp. were isolated; 8 were identified as A. baumannii and 10 as A. lwoffii. Five of A. bauma...