Ojan Assadian was born in Vienna, Austria. He received a medical degree from the University of Vienna in 1997 and the Diploma in Tropical Medicine and Hygiene from the London School of Hygiene and Tropical Medicine in 2000. Since 1999, he has been with the Medical University of Vienna, where he became Associate Professor in Hygiene and Medical Microbiology in 2003, “habilitation-“thesis: „Epidemiological methods for detection, analysis, and interpretation of nosocomial infections and pathogens with special resistance and virulence factors“. In October 2004, he was awarded tenure track Professor at the Medical University of Vienna. Since 2005 he worked for the Medical University of Vienna as Senior Clinical Specialist and Chairperson of the Infection Prevention and Control Committee at Prince Court Medical Centre, Kuala Lumpur, Malaysia. In 2008, he became acting Head of the Division of Hospital Hygiene/ Clinical Institute for Hygiene and Medical Microbiology at the Medical University of Vienna. In 2015, he was appointed as Professor of Skin Integrity and Infection Prevention at the University of Huddersfield, England, where his research and teaching work focuses on diagnostic, treatment and prevention of infection, including wound infections. Because of personnel reasons he returned to Vienna in 2017 and continued his clinical work as Consultant Infectious Diseases
International journal of preventive medicine, 2013
Nosocomial infections (NIs) are one of the most important health issues, particularly in developi... more Nosocomial infections (NIs) are one of the most important health issues, particularly in developing countries, because these infections cause high mortality and morbidity, and economic and human resource loss as a consequence. To date, most surveillance studies have been conducted in developed countries, and only a few have been performed in Iran. All of the few Iranian studies have been performed using paper-based collection forms, and none was conducted with the aid of an electronic patient data retrieving and collecting tool. The aim of this study is to determine the incidence of NIs in a big university hospital of Shiraz, with the help of specifically programmed surveillance software merging electronically the available patient data and the infection results input manually. The study was conducted prospectively through 6 months from 21(st) March up to 22(nd) September 2006, in a 374-bedded educational hospital. All patients admitted during this period were included in the study ...
Blood and body fluid exposures place healthcare workers at risk for blood-borne infections. To de... more Blood and body fluid exposures place healthcare workers at risk for blood-borne infections. To determine the extent of the problem in Iran, we assessed blood and body fluid exposure in healthcare workers in Fars Province hospitals. We distributed 2,118 questionnaires using a stratified random sampling method among nurses of these hospitals. We used Chi-square test, Student's t-test, and multiple logistic regression analysis for determining risk factors for exposure. The overall prevalence of blood and body fluid exposures was 79% with a rate of exposure to sharps devices of 50%. Hypodermic needles were involved in most exposures (73%) with the most common source of injury being needle recapping (35%). Blood was the most frequent contaminant (87%) in mucocutaneous exposures, most commonly associated with inserting and removing intravenous lines (50%). Sharps injuries were independently associated with gender, professional level, and hospital location; mucocutaneous exposures were...
Vascular graft infection is a rare but serious complication of vascular reconstructive surgery. T... more Vascular graft infection is a rare but serious complication of vascular reconstructive surgery. This in vitro study investigated the antimicrobial efficacy of a new, silver-triclosan collagen-coated polyester vascular graft compared with a silver collagen-coated polyester vascular graft alone during the first 24 hours. The antimicrobial efficacy of the investigated vascular grafts was assessed by performing a time-kill kinetic assay following Clinical and Laboratory Institute Standards-approved guidelines M26-A. For the purpose of the experimental study, the ATCC 33591 strain of methicillin-resistant Staphylococcus aureus (American Type Culture Collection, Manassas, Va) was used. All assays were repeated sixfold. Bacterial survival numbers were obtained at 1, 4, 8, 12, and 24 hours using a standard plate count procedure. Bactericidal activity was defined as a 3 log(10) reduction factor (logRF), according to the approved guideline M26-A. Both antimicrobial vascular grafts achieved >3 logRF and fulfilled the efficacy criterion for bactericidal activity but performed differently in their speed of antimicrobial action. The silver-triclosan vascular graft achieved 3.37 logRF after 8 hours, and the silver vascular graft showed a 4.19 logRF after 24 hours. The silver-triclosan graft yielded significantly lower colony-forming units/mL counts after 4 hours compared with the silver graft (4.29 × 10(4) vs 1.03 × 10(6); P = .031). Both antimicrobial collagen-coated polymer vascular grafts showed bactericidal activity against methicillin-resistant Staphylococcus aureus in vitro. Although the silver-triclosan vascular graft showed a faster antimicrobial efficacy, the silver graft exhibited its antimicrobial properties after 24 hours. Which concept will protect an implanted vascular prosthetic graft better from bacterial contamination and subsequent infection needs to be investigated further in in vivo animal and clinical studies.
Purge- and intensive-purge decontamination of dental units contaminated with biofilm Sanierung vo... more Purge- and intensive-purge decontamination of dental units contaminated with biofilm Sanierung von mit Biofilm kontaminierten Dentaleinheiten durch Purgen und Intensivpurgen
When tested in the quantitative suspension test according to the prEN 12054, polihexanide meets t... more When tested in the quantitative suspension test according to the prEN 12054, polihexanide meets the requirements defined by this standard for an antiseptic. At a product concentration of 0.02%, the test organisms are reduced by ≥5 lg, or ≥3 lg under dirty conditions, respectively, within a contact time of 5 min. This agrees well with the accepted recommendation of 0.02% polihexanide for the application on chronic wounds. In the presence of sesamoid bone/cartilage a polihexanide concentration of 0.005% is sufficient effective. As this concentration does not appear to have any adverse effects it might be promising to analyze its suitability for the antiseptic irrigation of joints in the animal model.The combination of 0.1% polihexanide with undecylenamidopropyl betaine (Prontosan®) possesses the antiseptic properties specified above, too. However, with regard to the higher concentration of polihexanide, at least a repeated application of this formulation cannot be recommended for clea...
Based on the current literature, a risk/benefit analysis of the antimicrobial impregnation of sur... more Based on the current literature, a risk/benefit analysis of the antimicrobial impregnation of surgical sutures with triclosan is performed, focussing on efficacy and indication, risk of resistance development, toxicological characteristics, and environmental tolerance.From a toxicological point of view, there are no restrictions for triclosan-impregnated suturing materials. Environmental tolerance is also acceptable for this application area, because the amounts of triclosan involved pose no problems in terms of degradability. The use of surgical suturing material coated with triclosan is seen especially in contaminated wounds or where the risk of infection is high. In order to meet this requirement, the antimicrobial properties of triclosan are particularly emphasized.Both in vitro and in vivo, triclosan is highly effective against Staphylococcus spp., including MRSA, the pathogens most frequently involved in postoperative wound infections. Triclosan is not effective against Pseudo...
Blood and body fluid exposures place healthcare workers at risk for blood-borne infections. To de... more Blood and body fluid exposures place healthcare workers at risk for blood-borne infections. To determine the extent of the problem in Iran, we assessed blood and body fluid exposure in healthcare workers in Fars Province hospitals. We distributed 2,118 questionnaires using a stratified random sampling method among nurses of these hospitals. We used Chi-square test, Student's t-test, and multiple logistic regression analysis for determining risk factors for exposure. The overall prevalence of blood and body fluid exposures was 79% with a rate of exposure to sharps devices of 50%. Hypodermic needles were involved in most exposures (73%) with the most common source of injury being needle recapping (35%). Blood was the most frequent contaminant (87%) in mucocutaneous exposures, most commonly associated with inserting and removing intravenous lines (50%). Sharps injuries were independently associated with gender, professional level, and hospital location; mucocutaneous exposures were...
European Journal of Clinical Microbiology & Infectious Diseases, 2006
In the study presented here 251 nasal swabs obtained from medical staff were directly investigate... more In the study presented here 251 nasal swabs obtained from medical staff were directly investigated for MRSA using a commercial multiplex PCR system in parallel with conventional culture methods to determine the usefulness of PCR for rapid screening. Both methods identified 3.2% (8/251) of specimens as MRSA-positive; one sample was culture-positive only, and three were PCR-positive only. PCR correctly identified
Maggots of the green blowfly, Lucilia sericata, are used as an alternative to surgical interventi... more Maggots of the green blowfly, Lucilia sericata, are used as an alternative to surgical intervention and long-term antiseptic therapy for the treatment of chronic wounds. The secretions of maggots are known to have antibacterial properties. To quantify the bactericidal effect of secretions from larvae of L. sericata, an in vitro test model based on the modified European quantitative suspension test
Introduction: The aim of the present study was to determine the antimicrobial effect of various g... more Introduction: The aim of the present study was to determine the antimicrobial effect of various gel formulations on plaque formation; different tooth gels were compared to a toothpaste containing comparable antimicrobial ingredients with regard to its microbiocidal activity. The study was conducted under the assumption, that a chief requirement for the prevention of plaque formation is the combination of mechanical removal and antimicrobial activity, and not the sole capability of mechanical plaque removal. Methods: Ledermix® fluoride gel as commercially available with preservative, and without preservative and perfume oils, Elmex® gelée, and Meridol® toothpaste were tested in a standardized in-vitro test modification of the quantitative suspension test EN 1040. Instead of testing in a suspension, the respective product was directly placed on a standardized contaminated sterile stainless steel disk without adding any bio-burden. 50% egg yolk in Aqua dest. was used as a neutralizer. ...
Annals of The Royal College of Surgeons of England
This report is based on a Hygienist Panel Meeting held at St Anne's Manor, Wokingham on 24-25... more This report is based on a Hygienist Panel Meeting held at St Anne's Manor, Wokingham on 24-25 June 2009. The panel agreed that greater use should be made of antiseptics to reduce reliance on antibiotics with their associated risk of antibiotic resistance. When choosing an antiseptic for clinical use, the Biocompatibility Index, which considers both the microbiocidal activity and any cytotoxic effects of an antiseptic agent, was considered to be a useful tool. The need for longer and more proactive post-discharge surveillance of surgical patients was also agreed to be a priority, especially given the current growth of day-case surgery. The introduction of surgical safety checklists, such as the World Health Organization's Safe Surgery Saves Lives initiative, is a useful contribution to improving safety and prevention of SSIs and should be used universally. Considering sutures as 'implants', with a hard or non-shedding surface to which micro-organisms can form biofilm ...
substances were Tetracycline, Povidone-lodine, Neomy- cin and Chloramphenicol. The reported overa... more substances were Tetracycline, Povidone-lodine, Neomy- cin and Chloramphenicol. The reported overall-obsewa- tion of chemical conjunctivitis after application of a pro- phylactic agent was 42.3% (591 33), typically after the use of Silver nitrate, Erythromycin or Tetracycline. The agent was determined by pediatricians (29%), in accord- ance to governmental decree (15%), by hospital policy (1 2%), eff ectiveness against Chlamydia and-
International journal of preventive medicine, 2013
Nosocomial infections (NIs) are one of the most important health issues, particularly in developi... more Nosocomial infections (NIs) are one of the most important health issues, particularly in developing countries, because these infections cause high mortality and morbidity, and economic and human resource loss as a consequence. To date, most surveillance studies have been conducted in developed countries, and only a few have been performed in Iran. All of the few Iranian studies have been performed using paper-based collection forms, and none was conducted with the aid of an electronic patient data retrieving and collecting tool. The aim of this study is to determine the incidence of NIs in a big university hospital of Shiraz, with the help of specifically programmed surveillance software merging electronically the available patient data and the infection results input manually. The study was conducted prospectively through 6 months from 21(st) March up to 22(nd) September 2006, in a 374-bedded educational hospital. All patients admitted during this period were included in the study ...
Blood and body fluid exposures place healthcare workers at risk for blood-borne infections. To de... more Blood and body fluid exposures place healthcare workers at risk for blood-borne infections. To determine the extent of the problem in Iran, we assessed blood and body fluid exposure in healthcare workers in Fars Province hospitals. We distributed 2,118 questionnaires using a stratified random sampling method among nurses of these hospitals. We used Chi-square test, Student's t-test, and multiple logistic regression analysis for determining risk factors for exposure. The overall prevalence of blood and body fluid exposures was 79% with a rate of exposure to sharps devices of 50%. Hypodermic needles were involved in most exposures (73%) with the most common source of injury being needle recapping (35%). Blood was the most frequent contaminant (87%) in mucocutaneous exposures, most commonly associated with inserting and removing intravenous lines (50%). Sharps injuries were independently associated with gender, professional level, and hospital location; mucocutaneous exposures were...
Vascular graft infection is a rare but serious complication of vascular reconstructive surgery. T... more Vascular graft infection is a rare but serious complication of vascular reconstructive surgery. This in vitro study investigated the antimicrobial efficacy of a new, silver-triclosan collagen-coated polyester vascular graft compared with a silver collagen-coated polyester vascular graft alone during the first 24 hours. The antimicrobial efficacy of the investigated vascular grafts was assessed by performing a time-kill kinetic assay following Clinical and Laboratory Institute Standards-approved guidelines M26-A. For the purpose of the experimental study, the ATCC 33591 strain of methicillin-resistant Staphylococcus aureus (American Type Culture Collection, Manassas, Va) was used. All assays were repeated sixfold. Bacterial survival numbers were obtained at 1, 4, 8, 12, and 24 hours using a standard plate count procedure. Bactericidal activity was defined as a 3 log(10) reduction factor (logRF), according to the approved guideline M26-A. Both antimicrobial vascular grafts achieved >3 logRF and fulfilled the efficacy criterion for bactericidal activity but performed differently in their speed of antimicrobial action. The silver-triclosan vascular graft achieved 3.37 logRF after 8 hours, and the silver vascular graft showed a 4.19 logRF after 24 hours. The silver-triclosan graft yielded significantly lower colony-forming units/mL counts after 4 hours compared with the silver graft (4.29 × 10(4) vs 1.03 × 10(6); P = .031). Both antimicrobial collagen-coated polymer vascular grafts showed bactericidal activity against methicillin-resistant Staphylococcus aureus in vitro. Although the silver-triclosan vascular graft showed a faster antimicrobial efficacy, the silver graft exhibited its antimicrobial properties after 24 hours. Which concept will protect an implanted vascular prosthetic graft better from bacterial contamination and subsequent infection needs to be investigated further in in vivo animal and clinical studies.
Purge- and intensive-purge decontamination of dental units contaminated with biofilm Sanierung vo... more Purge- and intensive-purge decontamination of dental units contaminated with biofilm Sanierung von mit Biofilm kontaminierten Dentaleinheiten durch Purgen und Intensivpurgen
When tested in the quantitative suspension test according to the prEN 12054, polihexanide meets t... more When tested in the quantitative suspension test according to the prEN 12054, polihexanide meets the requirements defined by this standard for an antiseptic. At a product concentration of 0.02%, the test organisms are reduced by ≥5 lg, or ≥3 lg under dirty conditions, respectively, within a contact time of 5 min. This agrees well with the accepted recommendation of 0.02% polihexanide for the application on chronic wounds. In the presence of sesamoid bone/cartilage a polihexanide concentration of 0.005% is sufficient effective. As this concentration does not appear to have any adverse effects it might be promising to analyze its suitability for the antiseptic irrigation of joints in the animal model.The combination of 0.1% polihexanide with undecylenamidopropyl betaine (Prontosan®) possesses the antiseptic properties specified above, too. However, with regard to the higher concentration of polihexanide, at least a repeated application of this formulation cannot be recommended for clea...
Based on the current literature, a risk/benefit analysis of the antimicrobial impregnation of sur... more Based on the current literature, a risk/benefit analysis of the antimicrobial impregnation of surgical sutures with triclosan is performed, focussing on efficacy and indication, risk of resistance development, toxicological characteristics, and environmental tolerance.From a toxicological point of view, there are no restrictions for triclosan-impregnated suturing materials. Environmental tolerance is also acceptable for this application area, because the amounts of triclosan involved pose no problems in terms of degradability. The use of surgical suturing material coated with triclosan is seen especially in contaminated wounds or where the risk of infection is high. In order to meet this requirement, the antimicrobial properties of triclosan are particularly emphasized.Both in vitro and in vivo, triclosan is highly effective against Staphylococcus spp., including MRSA, the pathogens most frequently involved in postoperative wound infections. Triclosan is not effective against Pseudo...
Blood and body fluid exposures place healthcare workers at risk for blood-borne infections. To de... more Blood and body fluid exposures place healthcare workers at risk for blood-borne infections. To determine the extent of the problem in Iran, we assessed blood and body fluid exposure in healthcare workers in Fars Province hospitals. We distributed 2,118 questionnaires using a stratified random sampling method among nurses of these hospitals. We used Chi-square test, Student's t-test, and multiple logistic regression analysis for determining risk factors for exposure. The overall prevalence of blood and body fluid exposures was 79% with a rate of exposure to sharps devices of 50%. Hypodermic needles were involved in most exposures (73%) with the most common source of injury being needle recapping (35%). Blood was the most frequent contaminant (87%) in mucocutaneous exposures, most commonly associated with inserting and removing intravenous lines (50%). Sharps injuries were independently associated with gender, professional level, and hospital location; mucocutaneous exposures were...
European Journal of Clinical Microbiology & Infectious Diseases, 2006
In the study presented here 251 nasal swabs obtained from medical staff were directly investigate... more In the study presented here 251 nasal swabs obtained from medical staff were directly investigated for MRSA using a commercial multiplex PCR system in parallel with conventional culture methods to determine the usefulness of PCR for rapid screening. Both methods identified 3.2% (8/251) of specimens as MRSA-positive; one sample was culture-positive only, and three were PCR-positive only. PCR correctly identified
Maggots of the green blowfly, Lucilia sericata, are used as an alternative to surgical interventi... more Maggots of the green blowfly, Lucilia sericata, are used as an alternative to surgical intervention and long-term antiseptic therapy for the treatment of chronic wounds. The secretions of maggots are known to have antibacterial properties. To quantify the bactericidal effect of secretions from larvae of L. sericata, an in vitro test model based on the modified European quantitative suspension test
Introduction: The aim of the present study was to determine the antimicrobial effect of various g... more Introduction: The aim of the present study was to determine the antimicrobial effect of various gel formulations on plaque formation; different tooth gels were compared to a toothpaste containing comparable antimicrobial ingredients with regard to its microbiocidal activity. The study was conducted under the assumption, that a chief requirement for the prevention of plaque formation is the combination of mechanical removal and antimicrobial activity, and not the sole capability of mechanical plaque removal. Methods: Ledermix® fluoride gel as commercially available with preservative, and without preservative and perfume oils, Elmex® gelée, and Meridol® toothpaste were tested in a standardized in-vitro test modification of the quantitative suspension test EN 1040. Instead of testing in a suspension, the respective product was directly placed on a standardized contaminated sterile stainless steel disk without adding any bio-burden. 50% egg yolk in Aqua dest. was used as a neutralizer. ...
Annals of The Royal College of Surgeons of England
This report is based on a Hygienist Panel Meeting held at St Anne's Manor, Wokingham on 24-25... more This report is based on a Hygienist Panel Meeting held at St Anne's Manor, Wokingham on 24-25 June 2009. The panel agreed that greater use should be made of antiseptics to reduce reliance on antibiotics with their associated risk of antibiotic resistance. When choosing an antiseptic for clinical use, the Biocompatibility Index, which considers both the microbiocidal activity and any cytotoxic effects of an antiseptic agent, was considered to be a useful tool. The need for longer and more proactive post-discharge surveillance of surgical patients was also agreed to be a priority, especially given the current growth of day-case surgery. The introduction of surgical safety checklists, such as the World Health Organization's Safe Surgery Saves Lives initiative, is a useful contribution to improving safety and prevention of SSIs and should be used universally. Considering sutures as 'implants', with a hard or non-shedding surface to which micro-organisms can form biofilm ...
substances were Tetracycline, Povidone-lodine, Neomy- cin and Chloramphenicol. The reported overa... more substances were Tetracycline, Povidone-lodine, Neomy- cin and Chloramphenicol. The reported overall-obsewa- tion of chemical conjunctivitis after application of a pro- phylactic agent was 42.3% (591 33), typically after the use of Silver nitrate, Erythromycin or Tetracycline. The agent was determined by pediatricians (29%), in accord- ance to governmental decree (15%), by hospital policy (1 2%), eff ectiveness against Chlamydia and-
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