جستجوی مقالات مرتبط با کلیدواژه « linezolid » در نشریات گروه « پزشکی »

E. faecium is the third most common cause of nosocomial infections. Linezolid (LNZ) is a reserve antibiotic recommended for infections caused by vancomycin resistant E. faecium (VREfm).  The aim of the present study was to investigate the prevalence of optrA gene among linezolid resistant E. faecium (LREfm) and to study the molecular epidemiology using pulse field gel electrophoresis (PFGE). Clinically significant LREfm were identified and antimicrobial susceptibility was performed by disc diffusion. Minimum inhibitory concentration (MIC) of linezolid, vancomycin, daptomycin and quinupristin/dalfopristin was determined by E-test. PCR and PCR-RFPL were performed for the detection of optrA/cfr gene and G2576T mutation respectively. Molecular epidemiology was studied by PFGE. A total of 1081 clinically significant Enterococci species were isolated which included E. faecium 63.5% (n=687) and E. faecalis 36.5% (n=394). LREfm (30/687) were further studied. Multidrug resistance and vancomycin resistance was 100% and 80%, respectively. Linezolid MIC range was 8-256µg/ml and the most common mechanism of resistance was optrA gene (83.3%) followed by G2576T mutation (33.3%). PFGE analysis demonstrated 4 major clones. The optrA gene mediated linezolid resistance was high and PFGE suggests resistance was emerging in the different background strains irrespective of resistance mechanism. Studies are required to investigate factors driving the emergence of linezolid resistance. The review suggests that this is the first report of optrA-mediated resistance in E. faecium from India.
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The present study aimed to investigate secondary bacterial infections among patients infected with severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). Coagulase-negative Staphylococci can infect immunocompromised patients. Linezolid resistance among Staphylococcus epidermidis is one of the most critical issues. In 2019, 185 SARS-CoV-2-positive patients who were admitted to North Khorasan Province Hospital (Bojnurd, Iran), were investigated. Patients having positive SARS-CoV-2 reverse transcriptase real-time polymerase chain reaction (RT-PCR) test results, who had a history of intubation, mechanical ventilation, and were hospitalized for more than 48 hours were included. After microbiological evaluation of pulmonary samples, taken from intubated patients with clinical manifestation of pneumonia, co-infections were found in 11/185 patients (5.94%) with S. epidermidis, Staphylococcus aureus, and Acinetobacter baumani, respectively. Remarkably, seven out of nine S. epidermidis isolates were linezolid resistant. Selected isolates were characterized using antimicrobial resistance patterns and molecular methods, such as Staphylococcal cassette chromosome mec (SCCmec) typing, and gene detection for ica, methicillin resistance (mecA), vancomycin resistance (vanA), and chloramphenicol–florfenicol resistance (cfr) genes. All of the isolates were resistant to methicillin, and seven isolates were resistant to linezolid. Nine out of 11 isolated belonged to the SCCmec I, while two belonged to the SCCmec IV. It should be noted that all patients had the underlying disease, and six patients had already passed away.The increasing linezolid resistance in bacterial strains becomes a real threat to patients, and monitoring such infections, in conjunction with surveillance and infection prevention programs, is very critical for reducing the number of linezolid-resistant Staphylococcal strains.

 Chronic Suppurative Otitis Media (CSOM) is defined as chronic inflammation of middle ear and mastoid cavity that may present with recurrent ear discharges. Its importance lies in its refractoriness to treatment and chronicity, leading to complications.  CSOM is almost always associated with mixed bacterial flora. Knowledge of the local microbial flora as well as continuous, periodic evaluation of microbiological pattern, and antibiogram of isolates are necessary to decrease the potential risk of complications by early institutions of appropriate treatment.

 In this prospective cross-sectional study, a total of 134 consecutive swab samples of the patients diagnosed with CSOM, referred to a tertiary care hospital in Kashmir Valley, India were included. The bacterial colonies were identified in line with standard procedures. Antimicrobial sensitivity testing (AST) was carried out according to the Clinical Laboratory Standards Institute (CLSI) guidelines by modified Kirby-Bauer disc diffusion method on Mueller Hinton agar (MHA) medium. The data was analysed using SPSS version 24 and the prevalence of the organisms was determined and expressed in percentages.

 Out of total 134 ear swabs processed, microbial growth was seen in 111 (83%). The most common organism isolated was Methicillin Resistant Staphylococcus aureus (MRSA) in 43 (39%) of the patients, followed by Pseudomonas in 37 (27.6%). 9 (8%) of the cases had fungal etiology. Linezolid (LZ) showed 100% sensitivity in Gram-positive Cocci whereas, Tigecycline (TIG) showed 100% sensitivity in Gram-negative Bacilli. All MRSA were 100 % sensitive to tetracycline, linezolid, amikacin. All the isolates of Pseudomonas were 100 % sensitive to Tigecycline, Ofloxacin, Colistin, Imipenem, Aztreonam, Cefepime.

 Isolation of various aerobic, anaerobic, and fungal isolates shows that different conditions of CSOM could be differentiated on microbiological grounds. Thus, for better management of CSOM, microbial classification of infection as well as drug sensitivity test of organisms recovered are essential for making appropriate decision of antimicrobials that will effectively eradicate the pathogen.

 Staphylococcus aureus is considered a normal flora by colonization in the nose and skin of humans, yet it is a major cause of nosocomial infections and a life-threatening pathogen. Among antibiotics, oxazolidinones and glycopeptides have activity against gram-positive pathogens.

 The present study aimed to determine the frequency and comparison of the minimum inhibitory concentration of tedizolid, linezolid, and vancomycin against extensively drug-resistant (XDR) S. aureus strains isolated from hospitalized patients.

 This descriptive-analytical study was performed on 58 S. aureus isolates collected from 164 hospitalized patients over the course of one year. The Kerby-Bauer test was used to identify XDR isolates. Broth microdilution test was used according to CLSI M100-S25 (2015) criteria to determine the minimum inhibitory concentration (MIC) of vancomycin, linezolid, and tedizolid.

 The frequency of XDR S. aureus clinical isolates was 28 (48.3%). Determining MIC showed that all XDR S. aureus isolates tested were susceptible to tedizolid (MIC, ≤ 2 μg/mL), while 92/8% (MIC, ≤ 4 μg/mL) and 60.70% (MIC, ≤ 2 μg/mL) of XDR isolates were categorized as susceptible to linezolid and vancomycin, respectively. The concentration of tedizolid that inhibited 90% of isolates (MIC90) was 2 μg/mL, 2-fold lower than linezolid (MIC90 = 4 μg/mL) and 64-fold lower than vancomycin (MIC90 = 128 μg/mL). There was a significant difference between the frequency of XDR isolates from the aspirate, trachea, and wound infections, so 22% of vancomycin-resistant isolates and all strains resistant to linezolid were isolated from hospitalized patients in the infectious ward (P = 0.04).

 We conclude that tedizolid has a beneficial effect on XDR isolates of S. aureus and possesses more potent in vitro activity than the rest agents.

Due to the contradictory results of the effects of Vitamin B6 in reducing the hematotoxic effects of linezolid, the present study aimed to investigate the possible role of Vitamin B6 administration in reducing linezolid‑related hematological toxicities in patients with chronic osteomyelitis.

In a randomized double‑blind placebo‑controlled clinical trial, patients with chronic osteomyelitis were randomly divided into two groups (n = 40 each): the intervention group received Vitamin B6 40 mg twice daily from the beginning of treatment with linezolid and the control group received placebo with linezolid, both for 21 days. Blood variables including hemoglobin (Hb), white blood cells (WBC), and platelets (PLT) were measured at baseline and at the end of the 1st, 2nd, and 3rd weeks (days 7, 14, and 21) of the intervention.

There was no significant difference between the groups regarding the count of WBC and PLT and level of Hb at evaluated time points. Furthermore, there was a significant decreasing trend in all parameters within both groups; however, the decreasing trend of both PLT and WBC was slower in the intervention (Vitamin B6) group compared to the placebo group.

Vitamin B6 has no significant effect in the reduction of hematological adverse effects of linezolid in chronic osteomyelitis patients. However, it could retard the decreasing trend of WBC and PLT counts.

Ocular inserts are usually polymeric thin films with increased ocular residence time and sustained drug release capacity. Sodium alginate is a biocompatible and biodegradable carrier; however, initial burst release of encapsulated drug within it, is recognized as a challenge. Grafting –addition of functional moieties to a polymer– is a technique to modify polymers’ physicochemical properties, including higher ability to control drug release. Linezolid (LNZ) solution is used in consecutive doses in treatment of antibiotic-resistant Gram-positive bacterial infections especially induced by methicillin resistant Staphylococcus aureus (MRSA). Grafted alginate copolymers were synthesized using butyl methacrylate (BMC) and lauryl methacrylate (LMC) at two different reaction times (12 hr and 24 hr). Copolymerization was evaluated by 1H-NMR, Ft-IR, and TGA. Copolymer safety was examined by cytotoxicity test against HEK-293 cell. Linezolid inserts were prepared using optimized copolymers and characterized. 1H-NMR, Ft-IR, and TGA confirmed the successful grafting of alginate copolymers. ALG-B24 and ALG-L12 showed the highest safety against HEK-293 cell line comparing with intact alginate. Linezolid insert characterization results indicated a slower linezolid release profile related to creation of a lipophilic structure. A better strength property for linezolid loaded ALG-B24 and ALG-L12 inserts was obtained while ALG-L12 showed a stronger adhesive force compared with intact alginate. Antibacterial efficacy on clinical isolated MRSA after 24 hr was similar to linezolid solution. Lipophilic alginate copolymer (ALG-L12) showed a sustained release capability while retaining its main feature in strong film forming ability so it seems to be a promising safe carrier.

Ventilator-associated pneumonia (VAP) caused by methicillin-resistant Staphylococcus aureus (MRSA) is a serious infection in an intensive care unit (ICU). Ventilator-associated MRSA pneumonia (VAMP) in critically ill patients causes a high rate of mortality.

This study mainly aimed to compare the clinical outcomes and associated drug safety perspective of linezolid and teicoplanin in VAMP treatment.

This retrospective study included 98 adult ICU patients with VAMP, where 42 patients (LZD group) and 56 patients (TPN group) received a standard dose of linezolid and teicoplanin, respectively, for their VAMP treatment. Adverse reactions associated with linezolid and teicoplanin were considered. Clinical outcomes and 30-day mortality rates were compared in both groups.

The LZD group showed a higher MRSA eradication rate (97%, n = 34) than the TPN group (94.3%, n = 53) (P = 0.034). The linezolid and teicoplanin therapy was suddenly discontinued in 19% and 5.3% of the patients in the LZD and TPN groups, respectively, before completing the full duration of antibiotic therapy due to developed adverse drug reactions (ADRs), including thrombocytopenia (LZD/TPN groups: 7/1 event), tachycardia (LZD group: 1 event), and nephrotoxicity (TPN group: 2 events). This discontinuation increased the total duration of antibiotic therapy in 19% (n = 42) and 5.3% (n = 56) of the patients (P = 0.034) in the LZD and TPN groups, respectively.

VAMP is a life-threatening event in critically ill ICU patients worldwide. In this study, teicoplanin showed better clinical outcomes with a certain higher level of drug safety compared to linezolid in the treatment of ventilator-associated MRSA pneumonia.

Nocardia cyriacigeorgica is a common environmental organism isolated from different clinical samples in Europe, Asia, and North America, predominantly from respiratory samples, but also from samples from several other sites.
In the current paper a disseminated Nocardia cyriacigeorgica infection in an immunocompromised patient was reported. The patient was admitted to the under study hospital with multiple cutaneous abscess such as lesion and paraspinal abscess developed to brain abscess.
Nocardia cyriacigeorgica was isolated from a sample of skin lesion based on phenotypic properties and sequencing method. Limited cases of Nocardia cyriacigeorgica in Iran are reported.

Linezolid has been recognized as a safe and effective medicine against a wide variety of Gram-positive pathogens.
The primary objective of this study was to assess utilization appropriateness of linezolid and explore the efficiency of protocol intervention to proceed to rational drug usage.
The project was conducted in a referral teaching hospital from September 2015 to January 2017 in two phases. In the first step, a six-month survey was performed to evaluate the prescribing appropriateness of linezolid. Patients receiving linezolid were identified using hospital IT system and the medical charts were analyzed based on accurate indications and duration of linezolid prescription. Subsequently, a restrictive protocol was developed and communicated after a consensus by Drug and Therapeutics Committee in May 2016. After introduction of the protocol, an active daily surveillance of patients was done by hospital pharmacists. The appropriateness of linezolid utilization and infectious consultations were compared before and after protocol implementation.
In the first phase of the study, the indication of linezolid was appropriate in 56.2% of cases and improved considerably to 68.6% (P value: 0.04) after protocol enforcement. Furthermore the duration of the linezolid consumption was correct in 66.6% of patients, increasing to 88.5% after protocol introduction (P value 0.07). In the first step, 56.9% of linezolid prescriptions were based on infectious disease consultation which enhanced remarkably to 87.5% in the second step (P value 0.001), while, 65.5% and 73.8% of these consultations were appropriate in the study surveys respectively.
The protocol intervention could improve appropriate prescribing of linezolid in the hospital setting. However, ongoing audit studies are recommended to maintain the rational prescription of linezolid.

Enterococcus is the second cause of urinary tract infections in hospitals and the third most common cause of nosocomial bacteremia. Overuse of antibiotics for the treatment of nosocomial infections, causes antibiotic resistance in enterococci resistant to antibiotics through their ability to acquire resistance to antibiotics through mutation or acquisition of genetic material carrying a resistance gene by conjugation or other methods.
This cross-sectional study, studied all of the patients admitted in the Khatam – Ol- Anbiya hospital wards during 2013-2015 that 60 cases of patients with nosocomial infections during this period . Demographic data collected from medical records. Samples collected and were sent to the microbiology laboratory. In order to investigate drug-resistant Enterococcusæ Antibiogram test by E-Test method were performed. Relevant descriptive variables were analyzed in SPSS software version 21 .
34 (56/7%) of patients were male. The patient age mean was 70/71 18/39 years. Age group 70-90 years, with 17 (27.9 %) were the most frequent nosocomial infections. Enterococcus dominant species in these patients was 45 (75%) Enterococcus faecalis. Antibiogram E-Test results showed that 9 cases (18.3%) were resistance to linezolid, 22 (36/7 %) resistance to imipenem, 15 (25 %) resistance to meropenem, 6 patients (10% ) resistance to teicoplanin, 9 (15%) were resistant to vancomycin.
Identification of common antibiotic resistance in every region has great importance and in addition prevents treatment failure. The result of these studies shows that, antibiotic-resistance patterns have changed, and vancomycin resistance, especially among E. faecium, is rising because of nosocomial infections

Linezolid (LZD), severed as the first oxazolidinone antibiotic, was active against multidrug-resistant gram-positive strains. LZD can induce thrombocytopenia, anemia and leukocytopenia. Currently, reports on pure red cell aplasia (PRCA) cases induced by LZD are relatively rare [4-7]. In this paper, we reported a patient with PRCA twice induced by LZD. A 37-year-old man was diagnosed with myelodysplatic syndrome (MDS) and underwent allo-HSCT from an unrelated donor with ABO blood type- and leukocyte antigen (HLA)-matching. After HSCT for 2 years, the patient suffered from refractory fever and headache. He was first treated with empirical antifungal agent and antibiotics for central nervous system (CNS) infection, but then changed to LZD therapy for little effect. Twenty-eight days after LZD treatment, the symptom improved significantly but the hemoglobin declined to 70 g/L and the reticulocyte level was only 0.23%. The LZD therapy was stopped and the fever and headache symptoms reoccurred 1 week latter. Then, erythropoietin (EPO) and halved dosage of LZD were used for treatment. The CNS infection and the anemia symptom relieved gradually and the level of hemoglobin and reticulocyte declined again. After blood transfusion, the half dose of LZD was sustained without anaemia recovery. In summary, patients with anemia, myelosuppressants history or potential abnormal proliferation of T cells may suffer PRCA with long term LZD treatment. The monitoring of complete blood count and reticulocyte count were necessary during LZD therapy. If the clinical condition permits, LZD dosage reduction and blood transfusion should be considered.

Infections due to Staphylococcus aureus have long been considered as a big challenge to clinicians. The innate ability of this microorganism to develop resistance to different antibiotics, has led to the appearance of MRSA (methicillin-resistant Staphylococcus aureus) and lately VRSA (vancomycin-resistant Staphylococcus aureus) strains, which are considered as major problems for both patients and clinicians. In this study, we tried to evaluate susceptibility pattern of S. aureus isolates against some prevalent antibiotics as well as some infrequent ones. This inquiry was performed on 238 clinical samples, collected from different wards of Imam Reza Hospital of Mashhad between 2011 and 2012, which were previously defined as S. aureus and stocked in -70°C. Kirby-Bauer’s disc diffusion was performed for the following antibiotics: quinupristin-dalfopristin, linezolid, cefoxitin and mupirocin according to EUCAST 2014 (v. 4), cotrimoxazole, doxycycline, tigecycline, oxacillin based on CLSI 2012 (M100-S22) and vancomycin according to CLSI 2007 guidelines. Out of 238 samples, 5.88% were resistant to quinupristin-dalfopristin; 5.46% to linezolid; 60.92% to Co-trimoxazole; 31.93% to doxycycline; 18.90% to tigecycline; 5.04% to vancomycin; 9.24% to mupirocin; 43% to oxacillin and 46.21% of our isolates were resistant to cefoxitin. Coming across isolates with reduced susceptibility to quinupristin-dalfopristin and resistant to linezolid in this study are worrisome although these antibiotics are not used in our hospital. This might be a new challenge in the treatment of MRSA.

Vancomycin-resistant Enterococcus (VRE) has been established as a significant health-care associated problem, and caused significant morbidity and mortality.. This study was aimed to determine prevalence of VRE colonization in severely ill patients admitted to Pediatric Intensive Care Unit (PICU), and identify potential risk factors for colonization, and in vitro susceptibility of VRE to linezolid..Patients and Rectal swabs were taken from 71 children 18 years old or younger who were admitted with serious systemic illness, including malignancy, chronic kidney, lung or liver diseases, treatment with chemotherapeutic agents, immunodeficiency, treatment with high-dose corticosteroids, malnutrition, previous treatment with 2nd or 3rd generation cephalosporin, aminoglycoside, and broad-spectrum β-lactam antibiotics within the past 3 months. Demographics and known risk factors were retrieved and assessed by statistical methods.. A total of 71 patients with a mean age of 29.1 ± 38.5 months were enrolled in this study. The prevalence of VRE rectal colonization was 66.2%. None of the potential risk factors including age, gender, comorbidities, previous admission into ICU, length of stay in ICU, presence of invasive devices were significantly associated with VRE colonization. Linezolid-susceptible isolated strains accounted 97.9%.. The prevalence of VRE was higher compared to previous reports from local and international studies. In order to control the spread of VRE, appropriate use of antibiotics, adherence to infection control measures, and shortening the duration of ICU stay is highly recommended..

Vancomycin-resistant Enterococcus (VRE) has been established as a significant health-care associated problem, and caused significant morbidity and mortality. This study was aimed to determine prevalence of VRE colonization in severely ill patients admitted to Pediatric Intensive Care Unit (PICU), and identify potential risk factors for colonization, and in vitro susceptibility of VRE to linezolid.Patients and Rectal swabs were taken from 71 children 18 years old or younger who were admitted with serious systemic illness, including malignancy, chronic kidney, lung or liver diseases, treatment with chemotherapeutic agents, immunodeficiency, treatment with high-dose corticosteroids, malnutrition, previous treatment with 2nd or 3rd generation cephalosporin, aminoglycoside, and broad-spectrum β-lactam antibiotics within the past 3 months. Demographics and known risk factors were retrieved and assessed by statistical methods. A total of 71 patients with a mean age of 29.1 ± 38.5 months were enrolled in this study. The prevalence of VRE rectal colonization was 66.2%. None of the potential risk factors including age, gender, comorbidities, previous admission into ICU, length of stay in ICU, presence of invasive devices were significantly associated with VRE colonization. Linezolid-susceptible isolated strains accounted 97.9%. The prevalence of VRE was higher compared to previous reports from local and international studies. In order to control the spread of VRE, appropriate use of antibiotics, adherence to infection control measures, and shortening the duration of ICU stay is highly recommended.

The synthesis of 4-(substituted benzylidene)-2-(pyrazin-2-yl) oxazol-5(4H)-one was achieved in two steps, In first step, pyrazine-2-carboxamide  dissolved in EtOH, 10% KOH solution with ClCH2COOH produced compound 2-(pyrazine-2-carboxamido) acetic acid (II) and in second step, compound (II) in (CH3CO)2O with aromatic aldehyde, and catalyst potassium acetate produced title compounds 4-(substituted benzylidene)-2-(pyrazin-2-yl) oxazol-5(4H)-one (PA1-PA14). All the newly synthesized compounds structure were elucidated using various spectral techniques viz. FT-IR, 1H-NMR, GC-MS spectroscopy, and CHN elemental analysis data and screened for in vitro antimicrobial and antifungal activity. In vitro anti bacterial activity was carried out against organisms E.coli, K.pneumonia, S.aureus, and B. Subtilis as well as antifungal activity were carried out against A.niger and S.cerevisiae activity byminimum inhibitory concentration method. The most promising broad spectrum compounds PA3, PA4, and PA5 were observed and study data reveals that additions of different functional groups had varying effects on activity. In addition, the greater biological activities were observed when the electron-withdrawing groups like fluorine, bromine and chlorine were incorporated at p-position of the phenyl ring.

Miconazole is an imidazole antifungal agent, commonly applied topically to the skin or mucous membranes. The aim of this study was to examine the alternative method for gaining mechanism or the bimolecular changes caused by the possible teratogenic effects of Miconazole on mice fetus brain tissue using FTIR-Microspectroscopy. The mice were injected with Miconazole (60 mg/Kg) on gestation day 9. Fetuses were dissected on day 15 of gestation and morphological and histological studies on the fetus were carried out. Sections (10 μm) of control and Miconazole treated fetus brain tissue were used for FTIR measurement in the mid- infrared region. The results were shown by spectra 2nd derivative and also subtracting from control spectra. A lower intensity in the lipid (2800–3000 cm-1) and amid I (1600–1800 cm-1) regions of Miconazole treated mice fetus brain tissue was observed compared to the control mice fetus brain tissue. No major spectral shifting was observed at amide I band, amide II band and nucleic acid regions. As a conclusion, FTIR-Microspectroscopy can be a useful tool for teratogenic measurement with a unique ability to identify the modified bimolecular structures in mice fetus tissues.