Prevalence of high-level gentamicin-resistant Enterococcus faecalis and Enterococcus faecium in an Iranian hospital

This study was designed to determine the molecular characteristics and antimicrobial resistance of enterococcal strains isolated from patients admitted to an Iranian Hospital. Enterococcal strains were isolated from the burn patients. All strains were screened for genes encoding resistance to aminoglycoside aac(6')-Ie-aph(2'')-Ia, aph (3'), ant (4'), resistance to vancomycin (vanA, vanB), resistance to tetracycline (tetK, tetL, tetM, tetO), and resistance to erythromycin (ermA, ermB, ermC) by PCR and multiplex PCR-based methods. Genetic diversity was evaluated via Random Amplified Polymorphic DNA (RAPD)-PCR. All enterococcal isolates showed complete sensitivity to vancomycin with MIC � 0.5μg/ml. Resistance to gentamicin, tetracycline, erythromycin, ciprofloxacin or quinopristin-dalfopristin was detected, whilst more than 96.2% of isolates were high-level gentamicinresistant (HLGR) and multiple drug resistant. The most prevalent aminoglycoside resistance gene was aac(6')-Ie-aph(2'')-Ia, that was found in 96.2% (26/27) of the isolates. The most prevalent tetracycline resistance genes were tetM, found in 85.1% (23/27) followed by tetL and tetO found in 7.4% (2/27) of the isolates. The ermA and ermB genes were detected in 33.3% (9/27) and 44.4% (12/27) of the isolates respectively. RAPD-PCR analysis yielded 17 distinct profiles among 27 investigated isolates. One cluster of isolates shared the same RAPD pattern, while 16 isolates had unique RAPD pattern. Our study showed that during the examination time period one RAPD genotype was the common type and was disseminated among patients in the burn unit. Interestingly, most of these strains had an identical or very similar antibiotic and gene resistance pattern

Phenotypic and genotypic characteristics of tetracycline resistant Acinetobacter baumannii isolates from nosocomial infections at Tehran hospitals

Objective(s): To date, the most important genes responsible for tetracycline resistance among Acinetobacter baumannii isolates have been identified as tet A and tet B. This study was carried out to determine the rate of resistance to tetracycline and related antibiotics, and mechanisms of resistance. Materials and Methods: During the years 2010 and 2011, a total of 100 A. baumannii isolates were recovered from patients in different hospitals of Tehran, Iran. Antimicrobial susceptibility to tetracycline, minocycline, doxicycline and tigecycline was evaluated by E-test. Polymerase chain reaction (PCR) of the tet A and tet B genes was performed using specific primers, after which the isolates were subjected to Repetitive Extragenic Palindromic-PCR (PCR) to identify the major genotypes. Results: Of all isolates, 89 were resistant to tetracycline (MIC50 = 32 mu g/ml, MIC90 = 512 mu g/ml). Minocycline with the resistant rate of 35 (MIC50 = 16 mu g/ml, MIC90 = 32 mu g/ml) and doxicycline with the resistant rate of 25 (MIC50 = 16 mu g/ml, MIC90= 32 mu g/ml) have a good activity against A. baumannii isolates. All isolates were sensitive to tigecycline. Frequencies of tet B and tet A genes and coexistence of tet A and tet B among the isolates resistant to tetracycline, were 87.6, 2.2 and 1.1, respectively. Distribution of REP-types among A. baumannii isolates was types A (40), B (30), C (10), D (5) and E (5). Conclusion: It seems that tet A and tet B genes play an important role in the induction of resistance towards tetracyclines used in this study. It is suggested that further studies focus on other antimicrobial drugs and combinations in order to achieve a successful therapy against multi drug resistance (MDR) A. baumannii strains in Iran

High prevalence of direct repeat unit types of 10di, 8 h and 8i among methicillin resistant Staphylococcus aureus strains with staphylococcal cassette chromosome mec type IIIA isolated in Tehran, Iran 11 Medical and Health Sciences 1103 Clinical Sciences

Background: The emergence of methicillin-resistant Staphylococcus aureus (MRSA) is a main concern in burn care centers worldwide. The some reports of MRSA in Iran suggested that MRSA with type SCCmec III is common among burn patients. The aim of this study was to determine the prevalence, virulence genes, and antimicrobial susceptibility of the direct repeat units (dru) types of MRSA with SCCmec IIIA isolated from burn wounds in a burn care center in Tehran, Iran. Methods: In total, 165 S. aureus isolates were collected from clinical samples. In order to detect MRSA isolates, the mecA gene was amplified through the polymerase chain reaction (PCR) method. Antimicrobial susceptibility was tested using the disc agar diffusion test. Moreover, the PCR method was applied to determine SCCmec types, virulence genes, and antimicrobial resistance genes. The dru region was sequenced and thereby, dru types and dru repeats were identified. A similarity matrix was used to create minimum spanning tree (MST). Results: The prevalence of MRSA was 69 (114 out of 165 isolates). Most of MRSA isolates (61 out of 114, 53.5) were SCCmec type IIIA. All MRSA isolates were vancomycin-susceptible and more than 68 of MRSA isolates with SCCmec type IIIA were mupirocin resistant. The successful dru typing of isolates with SCCmec type IIIA revealed fourteen different dru types. There were two new dru types, namely dt10di and dt7aj. MST analysis indicated the presence of the three clusters of dt10di (cluster I), dt8i-dt8 h (cluster II), and dt11c-dt10ao-dt11dd-dt11a-dt10a (cluster III). There were significant differences between clusters I and II respecting antimicrobial resistance pattern and virulence genes. Conclusion: Three main dru clusters are prevalent in the study setting. The main dru types in the setting are dt10di, dt8i, and dt8 h. Dru typing can be used to differentiate MRSA strains with SCCmec IIIA. © 2019 The Author(s)

Phenotypic and genotypic evaluation of fluoroquinolone resistance in clinical isolates of Staphylococcus aureus in Tehran

Background: Fluoroquinolones are broad-spectrum antibiotics widely used in the treatment of bacterial infections such as Staphylococcus aureus isolates. Resistance to these antibiotics is increasing. Material/Methods: The occurrence of mutations in the grlA and gyrA loci were evaluated in 69 fluoroquinolone-resistant S. aureus isolates from 2 teaching hospitals of Tehran University of Medical Sciences. Results: Out of the 165 S. aureus isolates, 87 (52.7) were resistant to methicillin and 69 (41.8) were resistant to fluoroquinolone. Fluoroquinolone-resistant S. atoms isolates had a mutation at codon 80 in the grlA gene and different mutational combinations in the gyrA gene. These mutational combinations included 45 isolates at codons 84 and 86,23 isolates at codons 84,86 and 106 and 1 isolate at codons 84, 86 and 90. Fluoroquinolone-resistant S. aureus isolates were clustered into 33 PFGE types. Conclusions: The findings of this study show that the fluoroquinolone-resistant S. aureus strains isolated in the teaching hospitals in Tehran had multiple mutations in the QRDRs region of both grlA and gyrA genes

Efficacy of 16S rRNA variable regions high-resolution melt analysis for bacterial pathogens identification in periprosthetic joint infections

Background: Accurate and rapid identification of microorganisms causing periprosthetic joint infections (PJIs) are necessary for choosing an appropriate antibiotic therapy. Therefore, molecular techniques are suggested for diagnosis in suspected PJIs. The Broad-range PCR and High-Resolution Melt Analysis (HRMA) were evaluated for the identification of causative organisms of PJIs in this study. Results: For 47 of 63 specimens, both the culture and broad-range PCR were positive. The culture was found to be able of organism�s detection in 74.6 (47/63) of patients. Of 47 positive cultures, 11 (23.4) were polymicrobial and 36 (76.59) were monomicrobial cultures, in which 34 (91.89) cases were detected by HRM assay. The sensitivity, specificity of HRMA vs monomicrobial culture were 91.89, 93.75, respectively. The sensitivity, specificity of total HRMA (mono + poly) vs culture were 82.92, 93.75. Conclusions: HRM assay coupled with broad-range PCR are effective screening, rapid, and relatively cost-effective methods for discrimination of PJIs especially in aiding culture method. Using computer programs such as the Matlab-2018b program for HRM data analysis is also valuable and helpful in diagnosis. © 2021, The Author(s)

Target protection as a key antibiotic resistance mechanism

Antibiotic resistance is mediated through several distinct mechanisms, most of which are relatively well understood and the clinical importance of which has long been recognized. Until very recently, neither of these statements was readily applicable to the class of resistance mechanism known as target protection, a phenomenon whereby a resistance protein physically associates with an antibiotic target to rescue it from antibiotic-mediated inhibition. In this Review, we summarize recent progress in understanding the nature and importance of target protection. In particular, we describe the molecular basis of the known target protection systems, emphasizing that target protection does not involve a single, uniform mechanism but is instead brought about in several mechanistically distinct ways

Echinococcosis/Hydatidosis in Ilam Province, Western Iran

Background: Hydatidosis is a zoonotic disease of global prevalence. It causes considerable health problems and economic losses throughout the world, including Iran. The objective of this study was to assess the current status of echinococcosis/hydatidosis in the province of Ilam (western Iran). Methods: From April to September 2011, 65 stray dogs were collected from urban and rural areas of Ilam City. Parasites were isolated from the dogs and stained with carmine. A taxonomic study was carried out by measuring different parts of helminths. Meat inspection documents from slaughterhouses in Ilam were used to assess the prevalence of hydatidosis during a 3-year period in sheep, cattle, and goats. ELISA test was used to detect the presence of antibodies to hydatidosis in human sera. Clinical records from 2000 to 2010 of either treated or diagnosed patients from public hospitals of this province were reviewed. Results: The prevalence of Echinococcus granulosus infection in stray dogs was 9. A total of 81,726 animals were assessed for hydatidosis; 2.94 (2403 cases) had liver hydatidosis and 2.34 (1918 cases) had lung hydatidosis. Within a 10-year period, 140 patients (91 females and 49 males) were treated for hydatidosis. Of 1200 human sera, 2.25 (27 patients) were seropositive for hydatidosis. Conclusion: Hydatidosis is endemic in Ilam Province especially in rural area. The health and economic losses caused by the disease are significant; thus, our efforts need to be focused on the control of this disease

Comparison of virulence factors and biofilm formation among Staphylococcus aureus strains isolated from human and bovine infections

The aim of this study was to find different prevalence of genes involved in the biofilm formation process and to assess the phenotypic and genotypic markers of biofilm formation among Staphylococcus aureus strains isolated from human and bovine infections. In this study, 215 S. aureus strains were collected from human and dairy cow's infections. The biofilm forming capacity of the strains was evaluated using a colorimetric microtiter plate assay. The genes encoding microbial surface components, recognizing adhesive matrix molecules (MSCRAMMs) (ebpS, eno, fib, fnbA, fnbB, cna and bap), and the intracellular adhesion (ica) genes (icaA, and icaD) were targeted by polymerase chain reaction (PCR)-based method. Approximately 70 of the isolates produced biofilm. Among these, 59.3 were producers of weakly adherent biofilms while 34.8 and 5.8 produced moderate and strong biofilms, respectively. The most prevalent gene was icaD found in 88.4 of the isolates, followed by icaA, fib and eno found in 87.9, 75.8 and 75.3 of the isolates, respectively. The bap gene was not detected in any of the isolates. The prevalence of ebpS and fnbA genes among bovine isolates were significantly higher than those in human isolates, whilst the prevalence of cm gene was significantly higher in the human isolates. In this study, a high prevalence of biofilm production was found among S. aureus strains isolated from human and bovine infections. Most biofilm producing isolates were positive for MSCRAMM, icaA, and icaD genes. (C) 2015 Elsevier Ltd. All rights reserved