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Abstract
Methicillin-resistant Staphylococcus aureus (MRSA) has presented special problems in intensive care units (ICUs) because of the difficulties in implementing infection control measures. The prevalence and rate of acquisition of MRSA were studied over thirty months in a nine-bed ICU. Nasal and groin swabs were taken on admission and then weekly, and other cultures as clinically indicated. Of 1361 admissions 119 were MRSA-positive on arrival. 21 cases had been identified before admission and the remainder were detected by screening; in 57 the positive result was known only after discharge. Of the 1242 admissions initially negative 68 acquired MRSA while in the ICU. The ICU had no known MRSA-positive patients on 185 (20.3%) of 914 days, the longest sequence being 17 days. Positive patients occupied 1387 (16.9%) of the 8226 available bed days. Length of stay predicted the risk of acquiring MRSA. Estimated from patients who completed each weekly screening cycle, the risk was 7.5% per week in the first week and 20.3% per week thereafter. The risk was not influenced by initial APACHE II score, the use of haemofiltration, or the number of MRSA-positive patients in the unit. The data suggest that a further 38 of those discharged between weekly screenings acquired MRSA, giving an incidence of 8.5%. MRSA was grown from blood in 17 patients, and from sputum in 53 (ICU-acquired in 18% and 47%). This study suggests that nearly 10% of admissions to a general ICU will be MRSA-positive, of whom only half will be identified before discharge. With standard prevention the risk of previously negative patients acquiring MRSA approximates to 1% per day in the first week and 3% per day thereafter, with nearly one-fifth progressing to bacteraemia; one-half will have MRSA in sputum. Patients with longer stays constitute a high-risk minority for whom additional measures such as decontamination with oropharyngeal and enteral vancomycin should be considered.
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Affiliation(s)
- D S Thompson
- Medway Maritime Hospital, Gillingham ME7 5NY, UK.
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Farhangnia L, Ghaznavi- Rad E, Mollaee N, Abtahi H. Cloning, Expression, and Purification of Recombinant Lysostaphin From Staphylococcus simulans. Jundishapur J Microbiol 2014; 7:e10009. [PMID: 25147708 PMCID: PMC4138633 DOI: 10.5812/jjm.10009] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2013] [Revised: 05/14/2013] [Accepted: 05/21/2013] [Indexed: 11/16/2022] Open
Abstract
Background: Staphylococcus aureus is one of the most common causes of nosocomial infections and its resistance to antibiotics is a global concern. Lysostaphin is an antimicrobial agent belonging to a major class of antimicrobial peptides and proteins known as the bacteriocins. It exhibits a high degree of anti-staphylococcal bacteriolytic activity. Objectives: In this study, high level of recombinant mature lysostaphin in Escherichia coli was produced by using pET32a expression vector. Materials and Methods: The S. simulans gene encoding lysostaphin was extracted, amplified by polymerase chain reaction (PCR), and sub-cloned in prokaryotic expression vector pET32a. E. coli BL21 (DE3) plysS were transformed with pET32a-lys and gene expression was induced by IPTG. The expressed protein was purified by affinity-chromatography using (Ni-NTA) resin. Results: PCR and sequencing results confirmed the successful cloning of the target gene into the vector. The expression of protein was induced by IPTG and high concentration of the recombinant protein was obtained via the purification process by affinity-chromatography. Conclusions: Our data showed that the recombinant mature lysostaphin protein produced by pET32a vector in E. coli system was very efficient.
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Affiliation(s)
- Leila Farhangnia
- Department of Biotechnology, Arak University of Medical Sciences, Arak, IR Iran
| | - Ehsanollah Ghaznavi- Rad
- Department of Microbiology and Immunology, School of Medicine, Arak University of Medical Sciences, Arak, IR Iran
| | - Neda Mollaee
- Department of Biotechnology, School of Medicine, University of Medical Sciences, Arak, IR Iran
| | - Hamid Abtahi
- Molecular and Medicine Research Center, Arak University of Medical Sciences, Arak, IR Iran
- Corresponding author: Hamid Abtahi, Molecular and Medicine Research Center, Arak University of Medical Sciences, Arak, IR Iran. Tel: +98-8614173502, Fax: +98-8614173526, E-mail:
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Hsu LY, Wijaya L, Tan BH. Management of healthcare-associated methicillin-resistantStaphylococcus aureus. Expert Rev Anti Infect Ther 2014; 3:893-905. [PMID: 16307502 DOI: 10.1586/14787210.3.6.893] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Healthcare-associated methicillin-resistant Staphylococcus aureus is a major cause of nosocomial infections worldwide, with significant attributable morbidity and mortality in addition to pronounced healthcare costs. Treatment results with vancomycin--the current recommended antibiotic for serious methicillin-resistant S. aureus infections--have not been impressive. The recent availability of effective antimicrobial agents other than glycopeptides, such as linezolid and daptomycin, as well as the anticipated approval of newer agents with diverse mechanisms of action, has somewhat ameliorated the threat posed by this organism. However, these drugs are expensive, and there is still no overall satisfactory strategy for reducing the incidence of healthcare-associated methicillin-resistant S. aureus in endemic regions. Although early results with the Society for Healthcare Epidemiology of America guidelines give cause for cautious optimism, long-term experience is lacking, and it is likely that these guidelines will have to be adapted according to local conditions and resources before implementation. Trends to keep in mind when considering the problem of healthcare-associated methicillin-resistant S. aureus include the advent of community-associated methicillin-resistant S. aureus, and the propensity of S. aureus to evolve and acquire resistance determinants over time. This was last vividly demonstrated by the handful of vancomycin-resistant S. aureus isolated recently, which had acquired the vancomycin resistance gene from vancomycin-resistant enterococci.
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Affiliation(s)
- Li-Yang Hsu
- Department of Internal Medicine, Singapore General Hospital, S169608, Singapore.
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Akpinar RB, Celebioglu A, Uslu H, Uyanik MH. An evaluation of the hand and nasal flora of Turkish nursing students after clinical practice. J Clin Nurs 2009; 18:426-30. [PMID: 19191990 DOI: 10.1111/j.1365-2702.2008.02514.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
AIM The purpose of this study was to evaluate and compare the hand and nasal flora of nursing students before and after the clinical practice. BACKGROUND Hospitals are places where infective agents abound. Healthcare workers, relatives of patients and students practising in the hospital medium are often exposed to these infective agents. Although the role of the hand and nasal flora of healthcare workers in the development of nosocomial infections has been emphasised by earlier studies, there are a limited number of studies which investigate the hand and nasal flora of nursing students. DESIGN Descriptive. METHODS This descriptive study involved 66 volunteer nursing students. Two samples of flora from both hands and nose of each student were obtained. The inoculated samples were then evaluated through routine bacteriological study methods. Chi-square and percentage calculations were used in comparisons. RESULTS None of the students had methicillin-resistant Staphylococcus aureus or methicillin-resistant coagulase-negative Staphylococcus colonisation in the hand samples before clinical practice, 6.1% of the students had methicillin-resistant Staphylococcus aureus and 4.5% had methicillin-resistant coagulase-negative Staphylococcus colonisation after the practice. Although the differences between the rates of contamination with pathogen micro-organisms in the hand and nasal flora of the student nurses before and after clinical practice were not significant, the rate of colonisation after clinical practice was higher. CONCLUSIONS In this study, the rate of colonisation after clinical practice was higher. These findings indicate that students might have been contaminated with bacteria during clinical practice. RELEVANCE TO CLINICAL PRACTICE The results of this study have practical importance in clinical practice. The role of the hand and nasal flora of nursing students in the development of nosocomial infections is significant. For this reason, some precautions, such as using gloves and handwashing with special solutions when needed, should be taken to prevent nosocomial infections and protect students against associated risks.
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Thompson D, Workman R, Strutt M. Decline in the rates of meticillin-resistant Staphylococcus aureus acquisition and bacteraemia in a general intensive care unit between 1996 and 2008. J Hosp Infect 2009; 71:314-9. [DOI: 10.1016/j.jhin.2008.12.010] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2008] [Accepted: 12/17/2008] [Indexed: 12/28/2022]
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Proliferation of antibiotic-producing bacteria and concomitant antibiotic production as the basis for the antibiotic activity of Jordan's red soils. Appl Environ Microbiol 2009; 75:2735-41. [PMID: 19286796 DOI: 10.1128/aem.00104-09] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Anecdotes, both historical and recent, recount the curing of skin infections, including diaper rash, by using red soils from the Hashemite Kingdom of Jordan. Following inoculation of red soils isolated from geographically separate areas of Jordan, Micrococcus luteus and Staphylococcus aureus were rapidly killed. Over the 3-week incubation period, the number of specific types of antibiotic-producing bacteria increased, and high antimicrobial activity (MIC, approximately 10 microg/ml) was observed in methanol extracts of the inoculated red soils. Antibiotic-producing microorganisms whose numbers increased during incubation included actinomycetes, Lysobacter spp., and Bacillus spp. The actinomycetes produced actinomycin C(2) and actinomycin C(3). No myxobacteria or lytic bacteriophages with activity against either M. luteus or S. aureus were detected in either soil before or after inoculation and incubation. Although protozoa and amoebae were detected in the soils, the numbers were low and did not increase over the incubation period. These results suggest that the antibiotic activity of Jordan's red soils is due to the proliferation of antibiotic-producing bacteria.
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Miyachi H, Furuya H, Umezawa K, Itoh Y, Ohshima T, Miyamoto M, Asai S. Controlling methicillin-resistant Staphylococcus aureus by stepwise implementation of preventive strategies in a university hospital: impact of a link-nurse system on the basis of multidisciplinary approaches. Am J Infect Control 2007; 35:115-21. [PMID: 17327191 DOI: 10.1016/j.ajic.2006.09.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2006] [Revised: 09/01/2006] [Accepted: 09/05/2006] [Indexed: 10/23/2022]
Abstract
BACKGROUND Current approaches in the control of methicillin-resistant Staphylococcus aureus (MRSA) in the large tertiary referral hospital have not been universally successful. METHODS The trend of MRSA rates and their relationship with stepwise implementation of preventive strategies in Tokai University Hospital during a 76-month period from September 1998 to December 2004, was retrospectively analyzed with a quasi-experimental design. RESULTS Implementation of strategies including a feedback process with case and epidemic reporting, an infection control team and office, and a preventive guideline for MRSA did not result in reduction in monthly MRSA rates in the hospital, as analyzed with Shewhart u charts. When infection control link nurses were organized and their activities became full-scale, there appeared significant reduction in arithmetic mean of the monthly rates of MRSA from 6.3% to 5.0% in June 2002. Meanwhile the mean values for monthly counts of new MRSA cases also dropped in 15 of 25 wards/units in June 2002, as analyzed with Exponentially Weighted Moving Average charts. Concurrently, there was a significant increase (17.3%) in the monthly consumption of handwashing liquid plain soap. Thereafter the MRSA rates remained low for 2 years within three standard deviations. CONCLUSIONS The sustained reduction of MRSA rates in the hospital can be related to introduction of the infection control link-nurse system on the basis of continuous enforcement of basic and multidisciplinary approaches such as hand-hygiene compliance.
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Affiliation(s)
- Hayato Miyachi
- Laboratory Medicine, Clinical Laboratory and Infection Control Office, Tokai University School of Medicine, Isehara, Kanagawa 259-1193, Japan.
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Williams AA, Sugandhi EW, Macri RV, Falkinham JO, Gandour RD. Antimicrobial activity of long-chain, water-soluble, dendritic tricarboxylato amphiphiles. J Antimicrob Chemother 2007; 59:451-8. [PMID: 17242037 DOI: 10.1093/jac/dkl503] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
OBJECTIVES To measure the antimicrobial activities of three series of homologous, dendritic tricarboxylato (three-headed) amphiphiles against a battery of bacteria and fungi. METHODS Three series of homologous dendritic amphiphiles were synthesized containing C13 to C22 fatty chains. Susceptibility of Escherichia coli, Klebsiella pneumoniae, Lactobacillus plantarum, Micrococcus luteus, Staphylococcus aureus, methicillin-resistant S. aureus (MRSA), Mycobacterium smegmatis, Saccharomyces cerevisiae, Candida albicans, Cryptococcus neoformans and Aspergillus niger to the amphiphiles was measured by broth microdilution and reported as the MIC. RESULTS Several amphiphiles from each homologous series, designed and constructed to overcome the low solubility of saturated long-chain fatty acids, had antimicrobial activity against MRSA (MIC = 36 mg/L), C. albicans (MIC = 4.4 mg/L), S. cerevisiae (MIC = 1.1 mg/L) and M. smegmatis (MIC = 8.9 mg/L). These amphiphiles had considerably better antimicrobial activities than the corresponding saturated fatty acids. Alkyl chain length influenced the values of MIC; longer chains (C18-C22) were generally more antimicrobial, but there was no uniform pattern among the microorganisms tested. CONCLUSIONS As the antimicrobial activity of the amphiphiles increased with increasing chain length, it is anticipated that maximum activity was not reached with these series. Thus, the identification of the optimal chain length would provide a target compound for development of low-cost, topical microbicides and anti-infectives. Further, these series of dendritic amphiphiles with the very long chains can be used as new water-soluble probes for elucidation of membrane structure and for identification of novel targets for antimicrobial design.
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Affiliation(s)
- André A Williams
- Department of Chemistry MC 0212, Virginia Tech, Blacksburg, VA 24061, USA
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Ioannou CJ, Hanlon GW, Denyer SP. Action of disinfectant quaternary ammonium compounds against Staphylococcus aureus. Antimicrob Agents Chemother 2007; 51:296-306. [PMID: 17060529 PMCID: PMC1797692 DOI: 10.1128/aac.00375-06] [Citation(s) in RCA: 243] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2006] [Revised: 07/21/2006] [Accepted: 10/17/2006] [Indexed: 11/20/2022] Open
Abstract
Mode-of-action studies concluded that alkyldimethylbenzylammonium chloride (ADBAC) (a blend of C(12), C(14) and C(16) alkyl homologues) and didecyldimethylammonium chloride (DDAC) are both membrane-active agents, possessing subtly different modes of action reflecting early cell interactions against Staphylococcus aureus. ADBAC and DDAC exhibited similar MIC behaviors from 0.4 ppm to 1.8 ppm over an inoculum range of 1 x 10(5) to 1 x 10(9) CFU/ml at 35 degrees C. For ADBAC and DDAC, an increased rapidity of killing against S. aureus (final concentration, 2 x 10(9) CFU/ml) was observed at 35 degrees C compared to 25 degrees C. Concentration exponents (eta) for killing were <2.5 for both agents, and temperature influenced the eta value. Examination of leakage and kill data suggested that a single leakage marker was not indicative of cell death. ADBAC and DDAC possessed Langmuir (L4) and high-affinity (H3/4) uptake isotherms, respectively. ADBAC molecules formed a single monolayer of coverage of cells at the end of primary uptake, and DDAC formed a double monolayer. Rapid cell leakage occurred at bactericidal concentrations, with total depletion of the intracellular potassium and 260-nm-absorbing pools released in this strict order. Autolysis was observed for ADBAC and DDAC at concentrations of 9 mug/ml (0.0278 mM and 0.0276 mM, respectively) and above, together with the depletion of approximately 30% of the internal potassium pool. Autolysis contributed to ADBAC and DDAC lethality, although high biocide concentrations may have inhibited autolytic enzyme activity.
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Affiliation(s)
- Christopher J Ioannou
- Quest International, R and D, Kennington Road, Ashford, Kent TN24 0LT, United Kingdom.
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Robotham JV, Jenkins DR, Medley GF. Screening strategies in surveillance and control of methicillin-resistant Staphylococcus aureus (MRSA). Epidemiol Infect 2006; 135:328-42. [PMID: 16836799 PMCID: PMC2870575 DOI: 10.1017/s095026880600687x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/25/2006] [Indexed: 11/06/2022] Open
Abstract
With reports of hospital-acquired methicillin-resistant Staphylococcus aureus (MRSA) continuing to increase and therapeutic options decrease, infection control methods are of increasing importance. Here we investigate the relationship between surveillance and infection control. Surveillance plays two roles with respect to control: it allows detection of infected/colonized individuals necessary for their removal from the general population, and it allows quantification of control success. We develop a stochastic model of MRSA transmission dynamics exploring the effects of two screening strategies in an epidemic setting: random and on admission. We consider both hospital and community populations and include control and surveillance in a single framework. Random screening was more efficient at hospital surveillance and allowed nosocomial control, which also prevented epidemic behaviour in the community. Therefore, random screening was the more effective control strategy for both the hospital and community populations in this setting. Surveillance strategies have significant impact on both ascertainment of infection prevalence and its control.
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Affiliation(s)
- J V Robotham
- Department of Biological Sciences, University of Warwick, Coventry, UK.
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Thorburn K, Taylor N, Saladi SM, van Saene HKF. Use of surveillance cultures and enteral vancomycin to control methicillin-resistant Staphylococcus aureus in a paediatric intensive care unit. Clin Microbiol Infect 2006; 12:35-42. [PMID: 16460544 DOI: 10.1111/j.1469-0691.2005.01292.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
This study assessed the effects of throat and gut surveillance, combined with enteral vancomycin, on gut overgrowth, transmission of methicillin-resistant Staphylococcus aureus (MRSA), infections and mortality in patients admitted to a paediatric intensive care unit (PICU). A 4-year prospective observational study was undertaken with 1241 children who required ventilation for >or=4 days. Patients identified as MRSA carriers following surveillance cultures of throat and rectum received enteral vancomycin. Twenty-nine (2.4%) children carried MRSA, 19 on admission and nine during treatment in the PICU; one patient was not able to be evaluated. Overgrowth was present in 22 (75%) of the carriers. Ten (0.8%) children developed 21 MRSA infections (15 exogenous infections in eight children at a median of 8 days (IQR 3-10.5); five primary endogenous infections at a median of 3 days (IQR 1-25) in three children when they were in overgrowth status; one child developed both types of infection). Enteral vancomycin reduced gut overgrowth significantly, completely preventing secondary endogenous infections. Transmission occurred on nine occasions over a period of 4 years. Four patients died, two (5.9%) with MRSA infection, giving a mortality (11.8%) similar to the study population (9.8%). No emergence of vancomycin-resistant enterococci or S. aureus with intermediate susceptibility to vancomycin was detected. A policy based on throat and gut surveillance, combined with enteral vancomycin, for critically-ill children who were MRSA carriers was found to be effective and safe, and challenges the recommended guidelines of nasal swabbing followed by topical mupirocin.
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Affiliation(s)
- K Thorburn
- Paediatric Intensive Care Unit, Royal Liverpool Children's Hospital, Alder Hey, Liverpool L12 2AP, UK.
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Weese J, Rousseau J, Willey B, Archambault M, McGeer A, Low D. Methicillin-ResistantStaphylococcus aureusin Horses at a Veterinary Teaching Hospital: Frequency, Characterization, and Association with Clinical Disease. J Vet Intern Med 2006. [DOI: 10.1111/j.1939-1676.2006.tb02839.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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van Gemert-Pijnen J, Hendrix MGR, van der Palen J, Schellens PJ. Performance of methicillin-resistant Staphylococcus aureus protocols in Dutch hospitals. Am J Infect Control 2005; 33:377-84. [PMID: 16153483 DOI: 10.1016/j.ajic.2004.10.009] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2004] [Accepted: 10/05/2004] [Indexed: 11/20/2022]
Abstract
BACKGROUND Although numerous studies have stressed the importance of compliance with methicillin-resistant Staphylococcus aureus (MRSA) protocols with regard to cost reduction and a safer environment for health care workers and patients, an evaluation of the usability of the protocols themselves is lacking. In this study, we evaluated the usability and performance of those protocols. METHODS The performance of MRSA protocols was examined in 5 Dutch hospitals by means of a questionnaire (n = 63), followed by a practical test (n = 50), in a stratified random sample of 3 types of health care workers (physicians, nursing staff, and cleaning personnel). The questionnaire consisted of constructs related to exposure to risk, risk perception, knowledge of and attitude toward the protocols and safety preventive measures, self-reported behavior, and social and organizational support. The practical test consisted of "what if" scenarios that simulate the actual use of the protocol as a guideline for solving infection problems. The health care workers were asked to verbalize their thoughts and actions while using the protocol. RESULTS The questionnaire demonstrated adequate knowledge of and attitude toward the MRSA protocols. However, the practical test revealed that the majority of respondents had problems with the accessibility, comprehensibility, applicability, and acceptability of the protocols. Problems not only occurred because of unclear information about the preventive measures and a poor infrastructure but also because of preventive measures that conflict with principles in providing care. CONCLUSION The protocols do not reflect the practical needs of the health care workers. In view of the different decisions that health care workers have to take in various circumstances, it would be impracticable to use the same MRSA protocol for all hospital staff. Finally, the practical test provided more reliable results than the questionnaire.
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Affiliation(s)
- J van Gemert-Pijnen
- Faculty of Behavioural Sciences, Department of Communication Studies, University of Twente, Enschede, The Netherlands.
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Giannoudis PV, Parker J, Wilcox MH. Methicillin-resistant Staphylococcus aureus in trauma and orthopaedic practice. ACTA ACUST UNITED AC 2005; 87:749-54. [PMID: 15911652 DOI: 10.1302/0301-620x.87b6.16292] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- P V Giannoudis
- St James's University Hospital, Beckett Street, Leeds LS9 7TF, UK.
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Abstract
AIMS To investigate the epidemiological and clinical aspects of MRSA among inpatients and outpatients presenting to hospital. METHODS Analysis of demographic, epidemiological, and clinical data collected on 385 children first identified as having MRSA between January 1998 and December 2003 in a 250 bed English children's hospital. RESULTS There were 267 inpatients and 118 outpatients. The number of new cases of MRSA declined from 72 in 1998 to 52 in 2003, whereas hospital activity increased. Ninety nine (37.1%) inpatients acquired MRSA outside the hospital; a further 90 occurred among 31 clusters of cases. One hundred and seventy eight (66.7%) inpatients were aged <2 years; cardiac services and paediatric & neonatal surgery accounted for 59.6% of cases. Dermatology and A&E accounted for 51.7% of outpatients; 73.8% of outpatients had recently previously attended the hospital. A total of 13.9% of inpatients with MRSA developed bacteraemia; MRSA accounted for 15% of Staphylococcus aureus bacteraemias. The risk of MRSA bacteraemia in colonised patients, and the proportion of S aureus bacteraemias that were MRSA, varied between specialties. Intravascular devices were the most common source of MRSA bacteraemia (63.4% of cases). The mortality rate was 7.3%. CONCLUSIONS Enhanced surveillance of MRSA can identify at-risk patient groups, thus facilitating targeting of control measures. The absence of a link between numbers of cases of acquisition of MRSA and bacteraemia suggests that the rise in MRSA bacteraemia may not solely reflect an increase in MRSA prevalence in children in the UK. The need for larger epidemiological studies is emphasised.
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Affiliation(s)
- A Adedeji
- Birmingham Children's Hospital, Steelhouse Lane, Birmingham B4 6NH, UK.
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Barrett SP, Simmons NA. Controlling MRSA: what is the way forward? J Hosp Infect 2005; 59:170-1. [PMID: 15694972 DOI: 10.1016/j.jhin.2004.12.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2004] [Accepted: 12/01/2004] [Indexed: 10/25/2022]
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Humphreys H, Smyth EG. Use of enteral vancomycin for the control of methicillin-resistant Staphylococcus aureus in intensive care units. J Hosp Infect 2005; 59:259-61; author reply 263-6. [PMID: 15694985 DOI: 10.1016/j.jhin.2004.08.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Abstract
Methicillin-resistant Staphylococcus aureus (MRSA) has presented special problems in intensive care units (ICUs) because of the difficulties in implementing infection control measures. The prevalence and rate of acquisition of MRSA were studied over thirty months in a nine-bed ICU. Nasal and groin swabs were taken on admission and then weekly, and other cultures as clinically indicated. Of 1361 admissions 119 were MRSA-positive on arrival. 21 cases had been identified before admission and the remainder were detected by screening; in 57 the positive result was known only after discharge. Of the 1242 admissions initially negative 68 acquired MRSA while in the ICU. The ICU had no known MRSA-positive patients on 185 (20.3%) of 914 days, the longest sequence being 17 days. Positive patients occupied 1387 (16.9%) of the 8226 available bed days. Length of stay predicted the risk of acquiring MRSA. Estimated from patients who completed each weekly screening cycle, the risk was 7.5% per week in the first week and 20.3% per week thereafter. The risk was not influenced by initial APACHE II score, the use of haemofiltration, or the number of MRSA-positive patients in the unit. The data suggest that a further 38 of those discharged between weekly screenings acquired MRSA, giving an incidence of 8.5%. MRSA was grown from blood in 17 patients, and from sputum in 53 (ICU-acquired in 18% and 47%). This study suggests that nearly 10% of admissions to a general ICU will be MRSA-positive, of whom only half will be identified before discharge. With standard prevention the risk of previously negative patients acquiring MRSA approximates to 1% per day in the first week and 3% per day thereafter, with nearly one-fifth progressing to bacteraemia; one-half will have MRSA in sputum. Patients with longer stays constitute a high-risk minority for whom additional measures such as decontamination with oropharyngeal and enteral vancomycin should be considered.
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Affiliation(s)
- D S Thompson
- Medway Maritime Hospital, Gillingham ME7 5NY, UK.
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