Electrospun Nanofibrous Biocomposite of Royal Jelly/Chitosan/Polyvinyl Alcohol (RJ/CS/PVA) Gel as a Biological Dressing for P. aeruginosa-Infected Burn Wound.

Burn wounds are vulnerable to various infections due to damage to the tissue and changes in immune responses. Pseudomonas aeruginosa is a critical bacterium that can cause burn wound infections, which can be life-threatening and delay wound healing. Therefore, it is essential to develop an efficient strategy to prevent the spread of infection in burn wounds. The present study aims to investigate the effectiveness of electrospun nanofibers of royal jelly on a chitosan/polyvinyl alcohol polymer scaffold in repairing burn wounds infected with Pseudomonas aeruginosa. To achieve this, the researchers analyzed the morphology and physicochemical properties of the synthesized nanofibers using SEM, FTIR, BET, and TGA analyses. They also examined the antibacterial properties of the nanofibers using agar diffusion and spread plate techniques. In addition, hemolysis tests were carried out to assess biocompatibility. Finally, the ability of the nanofibers to repair burn wounds infected with Pseudomonas aeruginosa was evaluated using a laboratory mouse model. The study results showed that the synthesized nanofibers had desirable morphology and physicochemical properties and significant antibacterial effects in both in vitro and in vivo conditions. Also, loading RJ into the polymer scaffold significantly reduced erythrocyte lysis. The wound healing and contraction rates were significantly higher than the control groups, and tissue repair, re-epithelialization, and collagen synthesis occurred faster, preventing the spread of infection to deeper tissue areas. Based on these findings, the synthesized system has the potential to serve as a suitable substitute for some invasive treatments and chemical drugs to improve chronic wounds and manage infection control in burn injuries.

A five-year systematic review and meta-analysis study on methicillin resistant Staphylococcus epidermidis strains in Iran.

Background and Objectives: One of the most prevalent drug-resistant bacteria is methicillin-resistant Staphylococcus epidermidis (MRSE) causing healthcare infections. Previously, a meta-analysis study on the frequency of MRSE was conducted from Mar 2006 to Jan 2016 in Iran. The present study aimed to evaluate the changes in this prevalence in the last 5 years in different cities in Iran. Materials and Methods: Published articles on the frequency of MRSE were collected from the Web of Science, PubMed, Scopus, Google Scholar, Cochrane Library, and Iranian databases from the beginning of 2016 to the end of 2020. Of the 503 records identified, 17 studies met the inclusion criteria, and their extracted data were analyzed using comprehensive meta-analysis version 2.0 (Biostat). Results: The analysis showed that the frequency of MRSE has decreased significantly in the last five years and reached 60.8 [95% confidence interval (95% CI) 54.2-66.9] among culture-positive cases of S. epidermidis in Iran. Conclusion: The noticeable reduction in the prevalence of MRSE in Iran could be due to the improvement of infection control programs and interruption of the pathogen transmission cycle. Another influential reason is the significant reduction in methicillin prescriptions by physicians for infections caused by staphylococci.

Molecular Epidemiology and Recycling of Staphylococcus aureus Resistant to Methicillin Among the Staff, Patients, and Surfaces in University Hospital in West Iran, Ilam.

BACKGROUND: Staphylococcus aureus is a human pathogen causing nosocomial infections and increased hospitalization and mortality among human communities. Methicillin-resistant S. aureus strains are considered a severe threat in nosocomial infections and cause complications in the remedy process of bacterial infections. In this study, 137 samples were collected from different departments, staff, and patients in Ilam hospital. METHODS: Eighty-eight samples of these strains were examined to test antibiotic resistance and diffusion. MIC (minimum inhibitory concentration) and PCR (polymerase chain reaction) were performed on the samples resistant to oxacillin. 36 (40.9%) strains were MRSA, and 52 (59.1%) isolates were MSSA. 44.4% of MRSA strains with IV SCCmec type. RESULTS: Fourteen different spa types were found using spa typing, of which the most abundant types were t037, t030, and t701, and three new types, including t15471, t15474, and t17470, were identified among the strains. The molecular analysis by MLST showed that the strains are classified into 11 different sequence types. Sequence type 239 and clonal complexes of 329 and 22 were dominant. ST239- spat037-SCCmec III was also identified as the most frequent clone of MRSA. The most identified clones were MRSA ST239-spa t037-SCCmec III. CONCLUSION: The results show the spa-type distribution between samples of patients, personnel, and surfaces, demonstrating MRSA circulation between patients and the environment. The results show the need to control environmental health.

Biosynthesis of titanium dioxide nanoparticles using Hypericum perforatum and Origanum vulgare extracts and their main components, hypericin and carvacrol as promising antibacterial agents.

OBJECTIVE: To evaluate the anti-bacterial activities of titanium dioxide (TiO) nanoparticles of Origanum (O.) vulgare and Hypericum (H.) perforatum extracts, carvacrol and hypericin against Staphylococcus (S.) aureus. METHODS: In this study, TiOnanoparticles of O. vulgare and H. perforatum extracts, carvacrol and hypericin, were prepared and their antibacterial effects were evaluated against Staphylococcus (S.) aureus. In this study, scanning electron microscope, fourier transform infrared spectrometer, atomic force microscopy, dynamic light scattering and zeta potential were used to investigate the structure of synthesized drugs. RESULTS: Anti-bacterial activity of synthesized NPs was tested by minimum inhibitory concentration (MIC), minimum bactericidal concentration and disc diffusion method. MICs of TiO-NPs synthesized using O. vulgare, H. perforatum, carvacrol and hypericin and TiO were obtained 250, 62.5, 250, and 250, and 500 µg/mL, respectively. The MBCs for all of these were obtained 1000 µg/mL. CONCLUSION: Green-synthesized of TiO nanoparticles provides a promising approach to the use of O. vulgare and H. perforatum, carvacrol and hypericin as novel agents and safer antibacterial compounds, especially anti-S. aureus compounds.

Encapsulation of Satureja khuzistanica jamzad essential oil in chitosan nanoparticles with enhanced antibacterial and anticancer activities.

Satureja khuzistanica jamzad (SKJ), which is a member of Lamiaceae, has various proven effects such as antispasmodic and anti-inflammatory, anti-diabetic, antioxidant, and antifungal properties. However, the use of essential oil of plants is limited due to their inherent instability in the environment. Encapsulation with nanoparticles in the nanogel forms is one of their stabilization methods. The aim of this study was to synthesize nano-gel based on chitosan (CS) and extracts of SKJ essential oil, and to evaluate the antibacterial and anticancer activities. SKJ essential oil was extracted using water distillation method. Then, it was loaded on CS particles using two-step process as following: droplets formation and freezing. The Dynamic Light Scattering (DLS), Fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM), and Zeta potential determination were used to evaluate the physical and chemical properties of CS-SKJ nanogel, which its result was acceptable. After confirmation of the loaded essential oil rate and releasing amount, the antibacterial effects were evaluated on five Gram-positive bacteria and five Gram-negative bacteria using microbroth dilution method. The encapsulation efficiency, size, polydispersity index, and zeta potential of nanoparticles were characterized were 30.74%, 571.00 nm, 0.451 and -67.2 mV, respectively. The results were significant not only on Gram-positive bacteria, but also on Gram-negative bacteria. The MIC range was between 7.8 and 500 µg/ml. The CS-SKJ nanogel has acceptable anticancer activities on KB and A549 tumor cell lines. the IC50 range was between 5.6 and 6.71 µg/ml. The results indicate that both CS particles and SKJ alone, and CS-SKJ nanogel could be considered as the outlook to produce new antimicrobial and anticancer drugs.

Anticancer properties of colicin E7 against colon cancer.

INTRODUCTION: Cancer is a major public health problem in the modern world. Every year, new cases of cancer are diagnosed around the world. Cancer cells are altered cells that have escaped the mechanisms that regulate natural growth. Bacteriocins are cationic peptides synthesized by ribosomes that are secreted by almost all groups of bacteria. Some bacteriocins have shown selective toxicity to cancer cells compared to normal cells. This makes them other candidates for research and clinical trials. AIM: Due to the high prevalence of colon cancer and its therapeutic problems, this study was performed on colicin E7 to evaluate its anti-colon cancer properties. MATERIAL AND METHODS: For this reason, colE7 was cloned in pet32c vector and purified protein was affected on HT-29 cells to evaluate the expression of p53 and bcl2. RESULTS: Our in silco analysis demonstrated that colicin E7 has 87.23% confidence as anticancer peptide by ACPred-FL program. First, a PCR reaction was performed using specific primers of the colicin E7 gene, which formed the 1728 bp fragment that belongs to this gene. CONCLUSIONS: Colicin E7 decreased the expression of bcl2 and increased P53. The results of this study showed the general effect of colicin E7 on cancer cells in vitro, which can be evaluated in the future with further experiments.

Corrigendum to "Traditional and Modern Cell Culture in Virus Diagnosis"[Osong Public Health Res Perspect 2016;7(2):77-82].

[This corrects the article on p. 77 in vol. 7, PMID: 27169004.].

The characterization of bacterial communities of oropharynx microbiota in healthy children by combining culture techniques and sequencing of the 16S rRNA gene.

The high incidence of bacterial respiratory infections has led to a focus on evaluating the human respiratory microbiome. Studies based on culture-based and molecular methods have shown an increase in the bacterial community that includes the bacterial phyla Firmicutes, Bacteroidetes, Actinobacteria, and Proteobacteria in the oropharynx of healthy individuals. Therefore, recognizing this microbial compound and subsequently identifying those carriers of specific pathogens can be of great help in predicting future infections and their control. In this prospective study, we sought to characterize the bacterial communities of the respiratory microbiome in healthy children aged between 3 and 6 years old by combining both cultural techniques and sequencing of the 16S rRNA gene. Seventy-seven oropharynx samples using Dacron swabs were collected from 77 healthy children in the kindergartens of Ilam, Iran. Bacterial identification was performed by phenotypic methods and in house developed PCR-based sequencing (the V1-V9 hypervariable region of the bacterial 16S ribosomal RNA gene). In total, 346 bacterial isolates were characterized based on phenotypic and sequencing-based molecular methods. The 3 most predominant phyla were Firmicutes (74%), Proteobacteria (22%), and Actinobacteria (4%). At the level of the genus, Staphylococci (coagulase-positive and coagulase-negative) and Streptococci were dominant. Also, the most commonly identified potentially pathogenic colonisers were S. aureus (75%), Enterobacteriaceae spp. (40.1%), and A. baumannii (15.6%). The present study identified 3 phyla and 9 family of bacteria in the oropharyngeal microbiome. Remarkably, the presence of potential pathogenic bacteria in the nasopharynx of healthy children can predispose them to infectious diseases, and also frequent exposure to human respiratory bacterial pathogens are further risk factors.

The synergistic effect of hydroalcoholic extracts of Origanum vulgare, Hypericum perforatum and their active components carvacrol and hypericin against Staphylococcus aureus.

AIM: This study was designed to evaluate the synergistic activities of hydroalcoholic extracts of medicinal plants Origanum vulgare and Hypericum perforatum and their active components, carvacrol and hypericin against Staphylococcus aureus. METHODS: The synergistic effects of the plants, as well as carvacrol and hypericin, were examined using a checkered method against S. aureus (ATCC 12600). RESULTS: A fractional inhibitory concentration of 0.5 was obtained for combination of O. vulgare and H. perforatum and 0.49 for combination of the active ingredients carvacrol and hypericin, both of which indicated a synergistic effect. CONCLUSION: This preliminary evaluation demonstrated a synergistic property of O. vulgare and H. perforatum extracts in treating S. aureus infection. This study indicates that combination of the plants, as well as combination of carvacrol and hypericin, might be used as a new antibacterial strategy against S. aureus.

Phytochemical Profiles and Antibacterial Activities of Hydroalcoholic Extracts of Origanum vulgare and Hypericum perforatum and Carvacrol and Hypericin as a Promising Anti-Staphylococcus aureus.

OBJECTIVES: Staphylococcus aureus, a Gram-positive bacteria, is ranked second among the causes of hospital infections and is one of the three main causes of food poisoning. In recent times, the spread of antibiotic resistance in S. aureus has become very worrisome. Therefore, research for new effective drugs is important. The present study aims to investigate the phytochemical profiles and antibacterial effects of hydroalcoholic extracts of Origanum vulgare (Lamiaceae family) and Hypericum perforatum (Clusiaceae family) and their active compounds on S. aureus (ATCC 12600) in vitro. METHODS: The identification of phytochemical compounds in both plants was performed by Highperformance liquid chromatography (HPLC), headspace-solid-phase microextraction (HS-SPME) and Fourier-transform infrared spectroscopy (FTIR). To investigate microbial susceptibility, minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) and disc diffusion method (DAD) were used. Finally, the results of the study were compared with methicillin. RESULTS: Of the 42 combinations of O. vulgare, carvacrol (48%) and of the 38 combinations of H. perforatum, hypericin (46.2%) were the most abundant. The MIC, MBC and DAD of O. vulgare and H. perforatum, carvacrol, hypericin and methicillin were 625, 625, 312.5, 78.12 and 384 µg/mL, 10000, 10000, 2500, 2500 and 384 µg/mL, and 15.66 ± 4.49, 12.66 ± 0.47 and 22 ± 0.81 mm, respectively. CONCLUSION: Due to the significant effects of O. vulgare and H. perforatum and their active components against S. aureus, it is expected that in the future, hypericin, carvacrol and their derivatives can be used as effective antibacterial agents against S. aureus.

Alarming and Threatening Signals from Health Centers About Multi Drug Resistance Staphylococcus haemolyticus.

OBJECTIVES: Nowadays, due to the biofilm formation among coagulase-negative staphylococci (CoNS), acquisition of antibiotic resistance and virulence genes could be noted. These organisms resemble other staphylococcus that harbor mecA gene, which encode methicillin resistance but the diversity in CoNS is higher than other species. Based on increasing antibiotic resistance in Staphylococcus haemolyticus, analyzing of phenotypic and genotypic biofilm formation, antibiotic resistance and genes involved in this process, SCCmec and ACME typing were the aims of the current study. METHODS: 256 clinical CoNS isolates were collected that 49 isolates were identified as S. haemolyticus. For evaluation the antibiotic resistance patterns, disk agar diffusion method was applied, and also biofilm assay carried out among methicillin resistant S. haemolyticus and SCCmec and ACME typing. RESULTS: The results of antibiotic susceptibility indicated that the highest resistance was found for cotrimoxazole and erythromycin (86.6%) and the frequency of blaA (96.5%) and msrA (79.3%) genes was much higher than others. Among MRSH isolates 58.6 % showed a weak biofilm phenotype and 41.4% demonstrated a moderate biofilm density. Also, among the biofilm correlated genes, IS 256 (79.31%) was the most frequent. The SCCmec typing of MRSH isolates indicated that the type V was dominant. CONCLUSION: Our findings indicated that the correlation between high rates of existence Is 256 gene and high prevalence of weak biofilm phenotype was among MRSH isolates. The current study revealed that multiple antibiotic resistance existed in S. haemolyticus isolates that is a warning for public health.

What about Urinary Tract Infections and its Antibiotic Resistance Bacteria in Ilam, Iran?

BACKGROUND: Because of the unknown situation of antibiotic resistance pattern in the main hospital in Ilam, Iran, we aimed to evaluate the antibiotic resistance pattern of uropathogenic bacteria obtained from referred patients to Imam Khomaini Hospital, Ilam, Iran. So, 114 bacteria were collected during 9-month period and evaluated for their antibiotic resistance patterns. RESULTS: Our results demonstrated that Escherichia coli as the dominant responsible for urinary tract infection. Our results demonstrated that 61.4 % (n = 70) of isolates were positive for E.coli, while lowest prevalence was observed for Staphylococcus aureus and Acinetobacter baumannii. The results also showed that 6.4% (n = 7) were metallo beta lactamase (MBL) producers. Our findings showed only 4 gram positive bacteria were obtained from patients with urinary tract infections including one methicillin resistant S. aureus (MRSA) and 2 vancomycin resistant Enterococcus faecalis (VRE). CONCLUSION: In conclusion, we strongly recommended to perform a perfect study among all hospitals in Iran to evaluate the situation of antibiotic resistance and make a real panel to control this issue.

Clonal Lineage Diversity, Antibiotic Resistance, and Virulence Determinants Among Methicillin-Resistant and Methicillin-Susceptible Staphylococcus aureus Isolated from Nurses at a Teaching Hospital in Ilam, Iran: Successful Nares Decolonization by Mupirocin.

BACKGROUND: Staphylococcus aureus is known to be responsible for nosocomial infections, and the typing method was useful in managing the reservoir of bacteria. The main aim of this study was to determine the prevalence of S. aureus in the nares and hands of nurses working in Imam Khomeini hospital, Ilam, Iran, as well as to determine the clonal relatedness, antimicrobial susceptibility profiles, different virulence, and resistance determinants among these isolates. The evolution of mupirocin activity in the eradication of methicillin-resistant S. aureus (MRSA) and methicillin-susceptible S. aureus (MSSA) colonization in the nares of the healthcare workers in Ilam, Iran, was also determined in this study. MATERIALS AND METHODS: In this cross-sectional study, 80 nurses, auxiliary nurses, and service workers from Imam Khomeini Hospital were enrolled. MRSA, antibiotic susceptibility, and virulence determinants were evaluated. Then, the isolates were subjected to pulsed field gel electrophoresis (PFGE) and Staphylococcal cassette chromosome mec typing. RESULTS: Our results demonstrated that 23% of isolates were MRSA. PFGE results demonstrated that pulsotypes A (3 out of 30; 10%) and J (3 out of 30; 10%), pulsotypes E (2 out of 30; 6.7%), M (2 out of 30; 6.7%), P(2 out of 30; 6.7%), and V (2 out of 30; 6.7%) were the most predominant pulsotypes, respectively. CONCLUSION: We cannot give conclusive suggestions about the correlation between nasal carriage and infections, but we suggest the monitoring of all healthcare workers annually, decontamination of their noses by using mupirocin and other antistaphylococcal agents, and also the washing of their hands at least every 2 h.

Association between biofilm production, adhesion genes and drugs resistance in different SCCmec types of methicillin resistant Staphylococcus aureus strains isolated from several major hospitals of Iran.

OBJECTIVES: The ability of bacteria to produce biofilm and adhesion makes them more resistant to antibiotics. The current study aims to evaluate the biofilm formation by Staphylococcus aureus and to determine the prevalence of adhesion genes, also their correlation with drug resistance. MATERIALS AND METHODS: A total of 96 MRSA were collected from hospitals of Iran's western provinces during 2012 to 2013. The presence of ica A, B, C, D, clfA, cna, fnbA, mecA genes were determined by PCR technique. Biofilm formation was studied by microtiter plate assay, the clonal relations of the strains were examined by SCCmec and Spa typing. RESULTS: The results demonstrated that 96 % of isolates were biofilm producers. The distributions of biofilm formation between isolates were 4.2%, 54.2%, 35.4% as high, moderate and weak, respectivelly. The highest biofilm production was observed from blood culture isolates. All virulent genes icaA,B, C, D, clfA, cna, fnbA were observed in moderate and weak biofilm formation isolates. Among high biofilm formation isolates, icaB and cna genes were not seen. Statistical analysis showed that there was a significant correlation between ica, fnbA and the biofilm production, but there was not a significant correlation between the type of samples and drug resistance, spa type and SCCmec type with biofilm production (P>0.05). Frequency of All virulent genes in type III SCCmec was higher than other types. CONCLUSION: The majority of MRSA isolates were biofilm producers and blood isolates ranked as the great biofilm producer. In these isolates ica D and fnbA genes are correlated with biofilm production.

Detection of Extended-Spectrum Beta-Lactamases (ESBLs) and Antibiotic Susceptibility Patterns in Klebsiella pneumoniae in Western, Iran.

BACKGROUND: Production of Beta-Lactamase enzymes, especially extended- spectrum Beta -Lactamases (ESBL), is a primary mechanism of resistance in these bacteria.The purpose of this study was detection of blaTEM, blaSHV, blaCTXM, blaCTX-M-15, blaPERand blaVEBin K. pneumoniae, isolated from clinical specimens by the PCR method and antibiotic susceptibility patterns in these strains isolated. MATERIALS AND METHODS: During a period from October 2015 to July 2016, 52 K. pneumoniae isolates were collected from general hospitals in the city of Sanandaj, Iran. After identifying the strains by biochemical testing, the disc diffusion method was used for determining antimicrobial susceptibility and screening the ESBL-producing isolates. Detection of blaTEM, blaSHV, blaCTX-M, blaCTX-M-15, blaPER and blaVEBESBL-producing K. pneumoniae was carried out by PCR. RESULTS: Out of 52-collected K. pneumoniae, highest and lowest rates of resistance related to co-trimoxazole with 67.3 % and amikacin with 30.7 %. 55.7% identified as MDR and 69.23% were ESBL-producing K. pneumoniae.blaSHV was the most prevalent gene in ESBL-producing K. pneumoniae. blaTEM,blaCTX-M,blaCTX-M-15 producing K. pneumoniae strains showed higher rates of drug resistant compared with negative strains (P < 0.05). CONCLUSION: Results of this study showed that the prevalence rate of ESBL-producing K. pneumoniae isolates is increasing in MDR strains, which raises concerns regarding the treatment of K. pneumoniae. Therefore, molecular research in the field of antimicrobial resistance of bacteria is essential to prevent the spread of resistant strains.

Antibiotic Resistance Patterns and Virulence Determinants of Different SCCmec and Pulsotypes of Staphylococcus Aureus Isolated from a Major Hospital in Ilam, Iran.

AIMS & OBJECTIVES: The aim of this study is to evaluate genetic relatedness, antibiotic resistance pattern, and virulence characteristics of different types of S. aureus isolated from air, surfaces, staff, and patients in a Public hospital in Ilam. METHODS & MATERIALS: A total of 88 of 140 staphylococci identified as S. aureus by conventional and molecular methods were used in this study. Isolate samples were obtained from surfaces, staff, patients, and hospital indoor air. The sampling from staff and surfaces was done through using swab and air by standard pump. Antimicrobial susceptibility testing and presence different resistant and virulence determinants was assessed. Isolates were then typed by pulsed-field gel electrophoresis (PFGE) and SCCmec typing methods. RESULTS: Out of 88isolates, 36 of them (40.9%) were MRSA. Among MRSA isolates, the range of resistance to antibiotic was 0% in vancomycin to 83.3% in gentamycin. The most prevalent resistant genes among gentamicin resistant S. aureus were acc (6')/aph (2")Ia and aph(3")IIIa. The most common erythromycin resistant gene was ermC. Surprisingly, SCCmec types I (30.5%), II (25%)were highly distributed. PFGE analysis showed 33 different pulsotypes. CONCLUSION: This study confirms that different isolates of MSSA and MRSA circulate in Ilam which differ in antimicrobial susceptibility, content of resistance, and virulence determinants.

Distribution of Class D Carbapenemase and Extended-Spectrum ß-Lactamase Genes among Acinetobacter Baumannii Isolated from Burn Wound and Ventilator Associated Pneumonia Infections.

INTRODUCTION: Resistance to Acinetobacter baumannii is dramatically on the rise in Iran. Therefore, it is important to study resistance pattern among Acinetobacter isolates which is a common cause of nosocomial infections. AIM: To investigate antibiotic resistance patterns and the role of resistant genes and biofilm formation in the induction of resistance among Acinetobacter baumannii isolated from burn wound and ventilator associated pneumonia infections. MATERIALS AND METHODS: Total 103 isolates such as 33 burn samples from Rasool Akram Hospital and 70 isolates from ventilated patients in Shahid Motahhari Hospital were identified with A. baumannii using biochemical method, and then identified to species level with PCR of gyrB and blaOXA-51 gene. Antibiotic sensitivity pattern for ß-lactam and carbapenem antibiotics was assessed using Agar disc diffusion test and E-test. The presence of different carbapenemase and metalo-ß-lactamase (blaOXA-51-like, gyrB, blaOXA-23-like, blaOXA-24-like, blaOXA-58, blaVEB, blaPER, blaGIM, blaSIM, blaIMP, blaVIM), extended-spectrum ß-lactamases (blaTEM, blaSHV) and two insertion sequences genes (ISaba1, IS1113) was assessed. Biofilm formation of all isolates was then assessed. Chi-square analysis or Fisher's-exact tests were used for statistical analysis. A p-value <0.05 was considered statistically significant. RESULTS: Colistin was the most effective antimicrobial agents, although 10.7% (11/103) of the isolates were resistant. The high rate of resistance to meropenem (93.2%) and imipenem (90.3%) was determined. Also, with exception of ampicillin-sulbactam, surprisingly the resistant rate was 28.2%, the resistance to ß-lactam antibiotic was dramatically increased. Co-existence of two and three blaOXA genes was also determined. The blaOXA-58 was detected in only one isolate. The blaTEM and blaOXA-23 was the most prevalent Extended-Spectrum ß-Lactamases (ESBL) gene. All isolates were biofilm producers. CONCLUSION: Antibiotic resistance is increasing among A. baumannii isolates which is due to excessive use of antibiotics and also acquired resistant genes and biofilm production. Resistance to nearly all antimicrobial agents especially colistin as end choice for treatment of multiple drug resistance A. baumannii is a big concern.

Determination of carbapenem resistance mechanism in clinical isolates of Pseudomonas aeruginosa isolated from burn patients, in Tehran, Iran.

Carbapenems are the most important therapeutic options that effect against serious infections caused by multidrug resistant Pseudomonas aeruginosa (MDR-PA) isolates. Carbapenems resistant isolates of P. aeruginosa are increasing worldwide. The aim of this study was to determine the carbapenem resistance mechanisms in clinical P. aeruginosa isolates from burn patients, in Tehran, Iran. A total of 53 non-duplicated isolates of carbapenem-resistant P. aeruginosa were collected from burn patients. The presence of carbapenemase genes were determined by PCR. AmpC overproducer isolates were detected by phenotypic method. The mutation and transcription level of oprD were determined by PCR-sequencing and quantitative Real-time PCR (RT-PCR), respectively. Twenty-seven (50.9%) isolates were positive for carbapenemase (blaVIM=25 and blaIMP=2) and showed high-level resistance to imipenem and meropenem. Twenty-eight isolates were AmpC overproducers. All isolates had a mutation in the oprD gene and down-regulation of oprD was found in 56.6% of MDR-PA isolates. Although the presence of carbapenemase is the common mechanism of resistant to carbapenem, but carbapenem resistance was found by oprD mutation-driven and the AmpC overproducing isolates in Tehran, Iran.

Characterization of biofilm formation, antimicrobial resistance, and staphylococcal cassette chromosome mec analysis of methicillin resistant Staphylococcus hominis from blood cultures of children.

INTRODUCTION:: Methicillin resistant Staphylococcus hominis (MRSHo) has been recognized as an important human pathogen, particularly in immunocompromised patients. METHODS:: A total of 19 S. hominis isolates were collected from children at the Children's Medical Centre, Tehran, Iran, from March 2012 to February 2013. MRSHo susceptibility against 13 antimicrobial and 3 antiseptic agents was determined using disk diffusion (DAD) and minimum inhibitory concentration (MIC), respectively. All isolates were subjected to polymerase chain reaction (PCR) assay for 15 distinct resistance genes, staphylococcal cassette chromosome mec (SCCmec), and arginine catabolic mobile elements (ACMEs). Biofilm production of the isolates was determined using a colorimetric microtiter plate assay. RESULTS:: Of the 19 isolates, 16 were resistant to oxacillin and harbored mecA. High resistance was also observed against trimethoprim/sulfamethoxazole (81.2%). All MRSHo isolates were susceptible to the three disinfectants tested (Septicidine-PC, Septi turbo, and Sayacept-HP). In total, 15 (78.9%) isolates produced biofilms. Three isolates had SCCmec types (V and VIII), 13 were untypable (UT), and 5 had ACME type II. CONCLUSIONS:: The results indicate that MRSHo with high antibiotic resistance and unknown SCCmec might become a serious problem in the future for the treatment of patients such as children.

Characterization of biofilm formation, antimicrobial resistance, and staphylococcal cassette chromosome mec analysis of methicillin resistant Staphylococcus hominis from blood cultures of children

Abstract INTRODUCTION: Methicillin resistant Staphylococcus hominis (MRSHo) has been recognized as an important human pathogen, particularly in immunocompromised patients. METHODS: A total of 19 S. hominis isolates were collected from children at the Children's Medical Centre, Tehran, Iran, from March 2012 to February 2013. MRSHo susceptibility against 13 antimicrobial and 3 antiseptic agents was determined using disk diffusion (DAD) and minimum inhibitory concentration (MIC), respectively. All isolates were subjected to polymerase chain reaction (PCR) assay for 15 distinct resistance genes, staphylococcal cassette chromosome mec (SCCmec), and arginine catabolic mobile elements (ACMEs). Biofilm production of the isolates was determined using a colorimetric microtiter plate assay. RESULTS: Of the 19 isolates, 16 were resistant to oxacillin and harbored mecA. High resistance was also observed against trimethoprim/sulfamethoxazole (81.2%). All MRSHo isolates were susceptible to the three disinfectants tested (Septicidine-PC, Septi turbo, and Sayacept-HP). In total, 15 (78.9%) isolates produced biofilms. Three isolates had SCCmec types (V and VIII), 13 were untypable (UT), and 5 had ACME type II. CONCLUSIONS: The results indicate that MRSHo with high antibiotic resistance and unknown SCCmec might become a serious problem in the future for the treatment of patients such as children.