Iranian Journal of Microbiology
Volume:8 Issue: 3, Jun 2016

Macrolide, lincosamide and streptogramin type B (MLSB) antibiotics are important in the treatment of Staphylococcus aureus infections and existence of isolates with ability to resist against MLSB antibiotics is worrisome.
In this cross sectional study, 101 S. aureus isolates were collected from patients of five selected hospitals in Tehran over a period of five months. Disk diffusion tests and differentiation between constitutive and inducible resistances were carried out by D-test. The presence of mecA, msrA, ermA and ermC genes were detected using PCR or multiplex PCR.
Out of 101 S. aureus isolates, 58 (57.4%) were methicillin resistant and 57 (56.4%) expressed resistance to erythromycin. The prevalence of constitutive MLSB (cMLSB), inducible MLSB (iMLSB) and MS (Negative) phenotype in all erythromycin resistant isolates were 71.9, 26.3 and 1.7%, respectively. Out of all the erythromycin resistant isolates, 57.8% harbored both ermA and ermC genes which possessed constitutive resistance. 8.7% of the isolates contained ermA gene alone which possessed inducible resistance with D phenotype and 5.2% of isolates just contained ermC gene which had inducible resistance with D phenotype. msrA gene was detected in 3.5% of the erythromycin resistant S. aureus isolates with constitutive resistance. None of the genes were detected among MS phenotypes.
In this study, most of S. aureus isolates carried both ermA and ermC genes and there was a significant relationship (P value ≤ 0.05) between different resistance phenotypes and erm genes.

The emergence of plasmid-mediated AmpC (pAmpC) β-lactamases conferring resistance to third-generation cephalosporins has become a major clinical concern worldwide. The aims of this study were to determine the prevalence of pAmpC-producing E. cloacae isolates and typing of them in Qazvin and Tehran provinces, Iran.
A total of 120 cefoxitin non-susceptible isolates of E. cloacae were obtained from educational hospitals of Qazvin and Tehran, Iran. Bacterial identification was performed by standard laboratory methods and API 20E strips. Susceptibility to cefoxitin was determined by Kirby-Bauer disk diffusion method. PCR and sequencing were employed to detect pAmpC families’ genes (ACC, FOX, MOX, DHA, CIT and EBC) and the clonal relatedness of pAmpC-positive isolates was evaluated by enterobacterial repetitive intergenic consensus (ERIC)-PCR method.
In total, 20 (16.7%) isolates of E. cloacae were positive for presence of pAmpC genes among those blaDHA-1 (14.2%) was the most common gene followed by blaCMY-2 (2.5%). Results of ERIC-PCR showed that that the prevalence of DHA-1 and CMY-2-producing E. cloacae isolates was not due to clonal outbreaks.
In present study, we showed the first emergence of DHA-1 and CMY-2 types of pAmpC-producing E. cloacae isolates in Iran. The appearance of pAmpC should be considered as a warning for the implementation of appropriate infection control and therapeutic policies in order to prevent the dissemination of these resistant organisms in our hospital settings.

Citrobacter freundii is an opportunistic pathogen causing nosocomial infections and resistant to various antibiotics. We aimed to determine the clonal relationship of C. freundii isolates using Pulsed-Field Gel Electrophoresis (PFGE).
Fifty clinical isolates of C. freundii were collected from the main hospital in Kermanshah. After antibiotic susceptibility testing and screening for extended-spectrum beta lactamase (ESBL), all isolates were genotyped by PFGE. The DNA fragment patterns were analysed using Gelcompar II version 6.6 software. The Dice coefficient was used to calculate similarities for cluster analysis.
The PFGE results of 12 (24%) and 38 (76%) ESBL positive and negative isolates, respectively, produced 39 clusters (X1-39) with different genotype patterns. The X1 and X2 clusters were the major clusters, each contained 3 isolates from different hospital wards. However, the majority of isolates showed a high genotypic diversity.
Results revealed the genotypic diversity of C. freundii isolates indicating the various sources for the bacterial isolates. However, the presence of isolates with similar genotypes indicates the common origin for these strains and may reflect the strain dissemination within the hospital wards, in particular in infectious ward and intensive care unit.

Anaerobic bacteria are recognized as important pathogens in surgical infections. However, they are the most overlooked microorganisms by the clinic and the laboratory because of the tedious culture techniques with longer turn-around times. The study was aimed to analyze the frequency of anaerobic bacterial surgical infections and their predisposing factors.
A retrospective study was conducted over a period of two years including patients with surgical infections. The specimens were processed by Gram staining, aerobic and anaerobic culture. The anaerobic bacteria were isolated using standard procedures. The predisposing factors and clinical presentation were studied in these patients.
A total of 261 specimens were received from patients with diverse infections from surgical wards. Ninety-one anaerobes were isolated from 64 (24.5%) surgical patients with a predominance of Gram-negative bacilli (37.4%). Anaerobic bacteria as monomicrobial isolates were seen in 21.9% isolates. Anaerobic bacterial isolation along with aerobic bacteria was seen in 71.9% of patients and polymicrobial anaerobic growth was detected in 6.3% of patients. Diabetes mellitus (28, 43.8%) was found to be the most frequent predisposing factor. Bacteroides fragilis group (20.9%) were the most frequent anaerobic Gram-negative bacilli followed by Prevotella spp. (12.1%). Peptostreptococcus anaerobius was the predominant anaerobic cocci isolated (14.3%). Necrotizing fascitis (34.4%) was the most common clinical presentation with anaerobic etiology followed by deep seated abscesses (23.4%).
Anaerobic bacteria were isolated from a significant proportion of surgical infections. To avoid therapeutic failures, anaerobic bacteria in surgical infections need to be recognized by surgeons and laboratorians.

Diarrheagenic Escherichia coli (DEC) strains are a major cause of intestinal syndromes in the developing countries. The aim of this study was to determine the prevalence of enterotoxigenic E. coli (ETEC) and enteroinvasive E. coli (EIEC) in relation to phylogenetic background from patients with diarrhea.
A total of 110 E. coli isolates were obtained from diarrhea patients in Sirjan, southeast of Iran. The E. coli isolates were confirmed using biochemical and bacteriological tests. DNA of E. coli isolates was extracted by boiling method and checked for existence of ETEC (LT and ST genes) and EIEC (ipaH gene) pathotypes and also characterize the phylogenetic groups on the basis of presence or absence of the chuA, yjaA genes and an anonymous DNA fragment, TspE4. C2 by multiplex PCR.
Out of 110 E. coli isolates, 32 (29.09%) were positive for ETEC (LT and ST genes) and 6 (5.45%) possessed EIEC (ipaH gene) pathotypes. Isolates fall into four phylogenetic groups: A (39.09%), B1 (20%), B2 (15.45%) and D (25.45%). Phylotyping of isolates of DEC indicated they were distributed in four phylogenetic groups including A (12 isolates), B1 (7), B2 (9) and D (10).
In this study, the DEC isolates were segregated into different phylogenetic groups. The majority of isolates belonged to phylo-groups A and D.

Brucellosis is an important health problem in developing countries and no vaccine is available for the prevention of infection in humans. Because of clinically infectious diseases and their economic consequences in human and animals, designing a proper vaccine against Brucella is desirable. In this study, we evaluated the immune responses induced by a designed recombinant chimera protein in murine model.
Three immunodominant antigens of Brucella have been characterized as potential immunogenic and protective antigens including: trigger factor (TF), Omp31 and Bp26 were fused together by EAAAK linkers to produce a chimera (structure were designed in silico), which was synthesized, cloned, and expressed in E. coli BL21 (DE3). The purification of recombinant protein was performed using Ni-NTA agarose. SDS-PAGE and anti-His antibody was used for confirmation purified protein (Western blot). BALB/c immunization was performed by purified protein and adjuvant, and sera antibody levels were measured by ELISA. otted.
SDS-PAGE and Western blotting results indicated the similarity of in silico designing and in vitro experiments. ELISA result proved that the immunized sera of mice contain high levels of antibodies (IgG) against recombinant chimeric protein.
The recombinant chimeric protein could be a potential antigen candidate for the development of a subunit vaccine against Brucella.

Neisseria meningitidis is transmitted from person-to-person. Thus, close contact with a healthy carrier can facilitate the spread of the bacteria and lead to life-threatening meningococcal disease. The aim of this study was to identify oropharyngeal carriers of N. meningitidis in volunteers preparing for military service before vaccination.
In a cross-sectional study, 226 volunteers entering military service were referred to the Shemiranat Health Center for meningococcal vaccination and assayed. Before vaccination, the participants underwent sampling of the throat using separate swabs. Thayer-Martin Agar medium and microbiological standard methods were used for culture and isolation of the organisms. The bacterial isolates were subjected to DNA extraction and polymerase chain reaction. The obtained data were descriptively analyzed.
Out of the 226 (100%) young volunteers, only 18 (8%) yielded Gram-negative diplococci. The results showed the presence of N. meningitidis (carriage rate: 8%) in their oropharyngeal regions. The isolated serogroups were C, A, Y, W-135, and X with frequencies of 50, 22.2, 16.6, 5.5, and 5.5, respectively.
This study showed that the carriage rate in young volunteers for military service is around 8% before vaccination. Although the rates for serogroups A and C were dominant, the existence of serogroups Y and W indicate the necessary revision of the A/C vaccine. More research is needed to determine serogroup diversity and decrease the risk of meningococcal disease in individual groups.

Infection is the most common cause of death among burnt patients and infection control decrease the rate of mortality. The use of sticky mat can control contamination by preventing the entrance microorganisms into the hospital wards. This study was designed to evaluate the sticky mats effect in reduction of microorganism’s entry by personnel shoes to burn intensive care unit (BICU).
This is a simple cross sectional study. We tested outer soles of personnel’s shoes with swap and cultured them before and after sticky mat contact in the entrance of BICU. Results were analyzed with IBM SPSS version 22 software. McNemar and Wilcoxon Signed Ranks tests were used.
We analyzed 60 outer soles of the shoes before and after contact with sticky mats. Coagulase negative Staphylococci, Gram positive bacilli, Staphylococcus aureus, Aspergillus fumigatus, Pseudomonas aeruginosa and Acinetobacter baumannii were isolated before contact from 57 ( 95%), 32 ( 53%), 4 (6.7%) and 3 (5%) cases, respectively. Coagulase negative Staphylococci, Gram positive bacilli, Staphylococcus aureus, Aspergillus fumigatus, Pseudomonas aeruginosa were isolated after contact from 36 (60%), 30 (50%), 16 (26.6%), 2 (3.3%) and 3 (5%) cases, respectively. No Acinetobacter was isolated after contact with sticky mat. Total isolated colonies before and after contact with sticky mats were 2573 and 830, respectively. There were significant statistically differences between the colony counts of coagulase ngative staphylococci, Gram positive bacilli, and Staphylococci aureus before and after contact with sticky mats (P. Regarding to statistical analysis, the effect of mat in removing the microorganisms was 56%. It confirms the effectiveness of sticky mat controlling the infection and reducing the amount of hospital contamination.

Trans-placental transmission of parvovirus B19 during pregnancy can causes adverse outcomes. Regarding its importance in prenatal care, we decided to study prevalence of parvovirus B19 infection among pregnant woman in Ardabil, Iran.
In a community based study with a cluster sampling, 350 pregnant women that attended in health care centers in Ardabil were selected. Serum samples were collected and Anti-B19 specific IgG was detected using commercial enzyme-linked immunosorbent assays (Euroimmune Elisa kit, Germany). Furthermore, a questionnaire filled for all participants during samples collection.
64.6% (226/350) of participants were Ardabil citizen and the rest were from rural area (124/350). Anti-B19-specific IgG antibody was detected in 69.1% of pregnant women (242/350). Participant's ages ranged from 15 to 34 years with average of 23 years. According to our study, seroprevalence of IgG antibodies had positive significant correlation with the participant's age (r=0.268) but there were no significant relations between B19 seropositivity and living area, family member, number of commensals, number of living children, and the amount of hemoglobin (p>0.05).
Approximately, one-third of the participants were at risk of primary B19 infection. Therefore, health education of pregnant women and screening of infected pregnant women is recommended to prevent fetal complications.