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O23 Impact of hypochlorite disinfection on MRSA rates
Infection control infection control measures. Detection of risk groups and infection sources and knowing the transmission ways of infections are important for the prevention from NI. In this study it was aimed to evaluate the knowledge level and behaviour models of hospital cleaning staff about NI in our setting which is a 1788 bedded tertiary care educational hospital. Methods: A questionnaire of with 21 questions was implemented to the hospital cleaning staff, who volunteered to enter the study. The questionnaire was composed of two parts: first part contained parameters for determination of sociodemographic properties and the second contained questions about evaluation of the knowledge about prevention from NI. Questions were prepared by using the references about the subject and by the help of the executives of the cleaning staff firm and statistics unit. Data were evaluated by SPSS 13.0 programme using Chi square and Student’s t tests. The questionnaire was completed by one by one interview method. Results: A total of 240 of 290 (82.7% of total, 122 male, 118 female, aged 36.2±8.7) hospital cleaning staff volunteered to enter the study. When evaluated according to the educational status; 55.4% were graduated from primary school and only 54% had been working in the hospital more than three years. Mean knowledge level was 18.15±3.97 (maximum 24). Knowledge level was not associated with gender, educational status and duration of working as cleaning staff (p > 0.05) but mean knowledge level of the staff working in the clinics was found higher than staff working in administrative sections (p < 0.05). 71.3% had received a formal education about prevention from NI before starting working but their mean knowledge level was not different from the others (p = 0.294). Only 48% and 50% knew the true order (x,y), while cleaning the patient rooms. 58.8% thought that they could prevent themselves from NI by hand washing before and after cleaning process, 80.8% stated they obeyed handwashing rules and 90.4% stated that they used gloves. Only 48.3% stated that they dried their hands by paper towels. Conclusion: Measurement of the level of the knowledge of the hospital cleaning staff may be beneficial for determination of the existing problems. Periodical well-established educational programmes should be started to improve the current situation.
O21 Evaluation of a rapid molecular dipstick assay for the direct detection of methicillin-resistant Staphylococcus aureus in clinical specimens U. Eigner, M. Holfelder, U. Wild, C. Bender, M. Kirstahler, A. Turnwald, W. Witte, M. Weizenegger, A. Fahr (Heidelberg, Wenigerode, DE) Objectives: Methicillin-resistant Staphylococcus aureus (MRSA) causes increasing healthcare problems worldwide. Rapid and sensitive screening methods for direct detection of MRSA are essential to limit further spread in the hospital. The purpose of this study was to evaluate the new molecular dipstick assay GenoQuick® MRSA (Hain Lifescience, Nehren, Germany) for the direct and specific detection of MRSA in clinical specimens. Methods: The analytical specificity of the assay was evaluated by using a subset of 25 MRSA isolates (including SCCmec types I−V); 17 methicillin-susceptible S. aureus (MSSA) and 38 coagulase-negative staphylocococi (CoNS) of different culture collections. The lower detection limit of the assay was determined by serial dilutions of MRSA strains representing SCCmec types I to IV. The test was evaluated for direct detection of MRSA in clinical swab specimens. MRSA carriage was analysed by both the standard culture methods [Chromagar MRSA (Becton Dickinson, Heidelberg, Germany), Columbia blood agar, trypticase soy broth] and two PCR assays [GenoQuick MRSA and GenoType® MRSA Direct (Hain Lifescience)]. Both PCR assays were performed directly from the swab and after overnight incubation in trypticase soy broth. MRSA isolates were confirmed using a mecA gene and S. aureus specific PCR. Susceptibility testing was performed with an automated system (VITEK 2, bioM´erieux, N¨urtingen, Germany). Results: The lower detection limit of 25 CFU was determined with serially diluted MRSA strains. For analytical specificity all MRSA strains
S5 representing SCCmec types I to V were tested positive by the assay. The MSSA and CoNS were tested negative, respectively. Of 187 patient specimens tested for clinical evaluation, 24 were identified MRSA-positive by culture and by both PCR assays. One specimen was positive only by PCR. Among the 163 culture-negative specimens, 162 were negative with both PCR assays. The GenoQuick assay showed a diagnostic sensitivity of 100%, and a diagnostic specificity of 99.4%, a positive predictive value of 96% and a negative predictive value of 100%. Time-to-result for the direct detection of MRSA from clinial specimens is reduced to 2h 20min with the molecular GenoQuick MRSA dipstick assay (2h 5min for amplification and 15 min for detection). Conclusions: The GenoQuick MRSA dip stick assay proved to be a rapid, sensitive and specific assay for direct detection of MRSA in clinical swab specimens in 2h 20min. O22 Throat swabs are necessary to reliably detect carriers of Staphylococcus aureus D. Mertz, R. Frei, B. Jaussi, U. Fl¨uckiger, A. Widmer (Basle, CH) Background: The anterior nares are considered to be the primary colonisation site of Staphylococcus aureus (S. aureus) and approximately 30% of healthy people carry the bacteria in their anterior nares. However, recent studies indicate that the throat may be an additional important site of colonisation (Nilsson P. J Clin Microbiol 2006). Most screening programmes for S. aureus including methicillin-resistant S. aureus (MRSA) require a swab from the nose only, and a swab of the throat is not considered as standard. Objectives: To determine the frequency of positive S. aureus cultures with positive samples from the throat and negative from the nares. Methods: Specimens were obtained with a sterile polyester fiber-tipped swab moistened with sterile saline from the anterior nares (5 rotations in each anterior nostril), the posterior wall of the pharynx, and the soft palate. Swabs were transported to the laboratory in a transport tube (M40 Transystem, Copan, Brescia, Italy) and put in selective enrichment broth (Chapman broth containing brain heart infusion broth with 6% NaCl, Biomedics, Madrid, Spain). Results: A total of 905 individuals were screened for S. aureus between 2000 and 2005. Complete data were unavailable from 54 individuals who were excluded. Overall, S. aureus was isolated in 386/851 (45.4%) individuals from any site.
No. of
% of overall
Nares
Screening results Throat
individuals
positive
pos pos neg
pos neg pos
50.8% 30.8% 18.4% 100%
neg
neg
196 119 71 386 465
Conclusion: Limiting S. aureus screening to the nares fails to identify 18.4% of carriers. Additional cost can be avoided by pooling the specimens while maintaining the higher sensitivity. Therefore, optimal screening for S. aureus should include swabs from both the nares and the throat. This may be even more important if screening is focused on MRSA carriage. O23 Impact of hypochlorite disinfection on MRSA rates A. Mahamat, F. MacKenzie, K. Brooker, D. Monnet, J. Daur`es, I. Gould (Nimes, FR; Aberdeen, Elgin, UK; Copenhagen, DK) Objectives: MRSA rates in a hospital in the North-East of Scotland were significantly declining due to a series of infection control interventions.
S6 These included terminal disinfection of the environment in isolation rooms and cohort areas by application of 1:1000 sodium hypochlorite in place of detergent (ECCMID ’06, abstract P1333). We evaluated the effect of replacing sodium hypochlorite with a standard detergent. Methods: From January 1997 to May 2006, monthly percentage, nonduplicate S. aureus clinical cases caused by MRSA were collated. In February 2005 hypochlorite cleaning solution as replaced by a standard detergent. Other infection control measures remained unchanged. Dynamic regression analysis with linear transfer functions and interrupted time-series analyses were used to estimate the effect to the intervention. Results: Previously, MRSA rates wee successfully reduced due to environmental screening (p = 0.03), use of hypochlorite for environmental disinfection (p = 0.002), use of alcohol based hand disinfection (p = 0.03) and patient admission screening (p < 0.01). Stopping the hypochlorite disinfection was associated with a sudden increase in clinical cases of MRSA from 10 to 25% over a 6 month period (p = 0.03), with levels approaching those seen prior to the start of the infection control programme in 2001 (see figure). Conclusions: Stopping hypochlorite environmental disinfection was strongly associated with an increase in clinical MRSA cases. This work adds significantly to the meagre published evidence that environmental contamination is important in the spread of MRSA.
Resistance surveillance O24 Multi-drug resistant enterococci among Portuguese swine after growth promoter ban C. Novais, A. Freitas, T.M. Coque, J.C. Sousa, L. Peixe (Porto, PT; Madrid, ES) Objectives: To determine antibiotic-resistant enterococci in Portuguese piggery samples and to analyse antibiotic resistance genes among these strains after European growth promoter ban. Methods: Samples from waste treatment and dry faeces from 2 pig farms in the South of Portugal were studied during 2006. Samples were plated onto selective Slanetz-Bartley agar with or without antibiotics. Bacterial identification was performed by both standard biochemical profiles and amplification of species specific genes. Antibiotic susceptibility (12 antibiotics) was determined by disk diffusion method (CLSI). Detection of genes coding for resistance [vanA, B, C1, C2, ermA, B, C, tetM, L, O, K, S, aac(6 )-Ie-aph(2 )Ia, aph(2 )-Ib,Ic,Id, aph(3 )-IIIa, vat E] were searched by PCR. Results: We identified 84 enterococci (9 E. faecalis, 17 E. faecium, 1 E. gallinarum, 2 E. casseliflavus and 55 Enterococcus spp.). Most isolates showed decreased susceptibility to tetracycline, minocycline, erythromycin, and quinupristin-dalfopristin (95%, 94%, 80%, 54%, respectively), and to a lesser extent to high-level of resistance (HLR) of streptomycin, nitrofurantoin, ciprofloxacin, HLR to gentamicin, chloramphenicol and ampicillin (52%, 33%, 32%, 21%, 11%, 10%). All were susceptible to glycopeptides. Non-susceptible isolates to tetracyclines, aminoglycosides and macrolides contained tetM (55%),
17th ECCMID / 25th ICC, Oral presentations tetL (54%), tetM+tetL (32%), tetS (5%), aac(6 )-Ie-aph(2 )-Ia (89%), aac(6 )-Ie-aph(2 )-Ia+aph(3 )-IIIa (47%), ermB (49%). vanC1 was linked to E. gallinarum, and vanC2 to E. casseliflavus as expected. Conclusions: Although all growth promoters were progressively removed from EU in the course of the last 10 years, antibiotic multiresistant enterococci were isolated in Portuguese piggeries. Whether persistence of these antibiotic resistant strains is due to selection by antibiotics or other agents deserves further studies. O25 Experiences and results from the surveillance programme of resistance in feed, food and animals in Norway (NORM-VET) 2000–2005 M. Norstr¨om, H. Tharaldsen, M. Sunde (Oslo, NO) Objectives: The monitoring programme for antimicrobial resistance in the veterinary and food production sectors (NORM-VET) was established in 2000. The goals of the programme are to monitor the antimicrobial resistance situation in feed, food and animals over time, in relation to the human situation and to the resistance situation in other countries. Data from NORM-VET could form a basis for risk assessments and be a tool for targeting interventions and further to evaluate the effectiveness of such interventions. This study was performed to summarise the experiences and results obtained during the first six years of the programme. Methods: The zoonotic agents Salmonella (from feed, animals and food) and Campylobacter jejuni (from broiler and broiler meat) were monitored annually. E. coli and Enterococcus spp. (indicator bacteria) were sampled from various animal species and meat products biannually. Specific clinical isolates from the routine diagnostic have been included biannually. The isolates have mainly been tested using a microdilution technique (VetMICTM). The minimum inhibitory concentrations were recorded and analysed in WHONET 5.3. For the categorising of the isolates as resistant or susceptible epidemiological cut-off values were applied. Results: The occurrence of resistance in the monitored species and products is in an international perspective low and the results from the first six years of the programme show that the situation is stable. Conclusion: Evaluation of the first six years of the programme has recognized that the relatively low number of isolates of each species and source included complicates the conclusions possible to draw from the data, especially evaluating trends over time. Even though the run costs of the programme has been limited to a minimum, it is still useful for the purpose of monitoring antimicrobial resistance within a country as Norway, where the resistance problem in the animal and food sectors still is at a very low level. It also consists as valuable source for further research of antimicrobial resistance mechanisms and development. However, the use of this source to perform risk assessments is limited as there still is a lack of even more specific data as for instance data on usage at animal or farm level. O26 Comparison of antibiotic susceptibilities of Staphylococcus aureus and S. intermedius isolates from dog owners and their dogs M. Boost, S. Lai, D. Ko, M. O’Donoghue (Kowloon, HK) Objectives: Antibiotic resistance in veterinary isolates has been reported to be higher than in human isolates due to frequent empirical use, and there are concerns about transfer of resistance between staphylococcal species. S. intermedius is the more common colonising species in dogs, but S. aureus, including MRSA, may also be present. Case reports suggest there can be cross-infection between companion animals and man. Increasing concern about MRSA in the community has led to recommendations for surveillance of antibiotic resistance in isolates from companion animals. This study compared antibiotic resistance in isolates of S. aureus and S. intermedius from dogs and their owners. Methods: A cross-sectional study of owners and their dogs was performed using a convenience sample of 800 pairs recruited at six veterinary practices. Nasal swabs were collected from both owner and
O21 Evaluation of a rapid molecular dipstick assay for the direct detection of methicillin-resistant Staphylococcus aureus in clinical specimens U. Eigner, M. Holfelder, U. Wild, C. Bender, M. Kirstahler, A. Turnwald, W. Witte, M. Weizenegger, A. Fahr (Heidelberg, Wenigerode, DE) Objectives: Methicillin-resistant Staphylococcus aureus (MRSA) causes increasing healthcare problems worldwide. Rapid and sensitive screening methods for direct detection of MRSA are essential to limit further spread in the hospital. The purpose of this study was to evaluate the new molecular dipstick assay GenoQuick® MRSA (Hain Lifescience, Nehren, Germany) for the direct and specific detection of MRSA in clinical specimens. Methods: The analytical specificity of the assay was evaluated by using a subset of 25 MRSA isolates (including SCCmec types I−V); 17 methicillin-susceptible S. aureus (MSSA) and 38 coagulase-negative staphylocococi (CoNS) of different culture collections. The lower detection limit of the assay was determined by serial dilutions of MRSA strains representing SCCmec types I to IV. The test was evaluated for direct detection of MRSA in clinical swab specimens. MRSA carriage was analysed by both the standard culture methods [Chromagar MRSA (Becton Dickinson, Heidelberg, Germany), Columbia blood agar, trypticase soy broth] and two PCR assays [GenoQuick MRSA and GenoType® MRSA Direct (Hain Lifescience)]. Both PCR assays were performed directly from the swab and after overnight incubation in trypticase soy broth. MRSA isolates were confirmed using a mecA gene and S. aureus specific PCR. Susceptibility testing was performed with an automated system (VITEK 2, bioM´erieux, N¨urtingen, Germany). Results: The lower detection limit of 25 CFU was determined with serially diluted MRSA strains. For analytical specificity all MRSA strains
S5 representing SCCmec types I to V were tested positive by the assay. The MSSA and CoNS were tested negative, respectively. Of 187 patient specimens tested for clinical evaluation, 24 were identified MRSA-positive by culture and by both PCR assays. One specimen was positive only by PCR. Among the 163 culture-negative specimens, 162 were negative with both PCR assays. The GenoQuick assay showed a diagnostic sensitivity of 100%, and a diagnostic specificity of 99.4%, a positive predictive value of 96% and a negative predictive value of 100%. Time-to-result for the direct detection of MRSA from clinial specimens is reduced to 2h 20min with the molecular GenoQuick MRSA dipstick assay (2h 5min for amplification and 15 min for detection). Conclusions: The GenoQuick MRSA dip stick assay proved to be a rapid, sensitive and specific assay for direct detection of MRSA in clinical swab specimens in 2h 20min. O22 Throat swabs are necessary to reliably detect carriers of Staphylococcus aureus D. Mertz, R. Frei, B. Jaussi, U. Fl¨uckiger, A. Widmer (Basle, CH) Background: The anterior nares are considered to be the primary colonisation site of Staphylococcus aureus (S. aureus) and approximately 30% of healthy people carry the bacteria in their anterior nares. However, recent studies indicate that the throat may be an additional important site of colonisation (Nilsson P. J Clin Microbiol 2006). Most screening programmes for S. aureus including methicillin-resistant S. aureus (MRSA) require a swab from the nose only, and a swab of the throat is not considered as standard. Objectives: To determine the frequency of positive S. aureus cultures with positive samples from the throat and negative from the nares. Methods: Specimens were obtained with a sterile polyester fiber-tipped swab moistened with sterile saline from the anterior nares (5 rotations in each anterior nostril), the posterior wall of the pharynx, and the soft palate. Swabs were transported to the laboratory in a transport tube (M40 Transystem, Copan, Brescia, Italy) and put in selective enrichment broth (Chapman broth containing brain heart infusion broth with 6% NaCl, Biomedics, Madrid, Spain). Results: A total of 905 individuals were screened for S. aureus between 2000 and 2005. Complete data were unavailable from 54 individuals who were excluded. Overall, S. aureus was isolated in 386/851 (45.4%) individuals from any site.
No. of
% of overall
Nares
Screening results Throat
individuals
positive
pos pos neg
pos neg pos
50.8% 30.8% 18.4% 100%
neg
neg
196 119 71 386 465
Conclusion: Limiting S. aureus screening to the nares fails to identify 18.4% of carriers. Additional cost can be avoided by pooling the specimens while maintaining the higher sensitivity. Therefore, optimal screening for S. aureus should include swabs from both the nares and the throat. This may be even more important if screening is focused on MRSA carriage. O23 Impact of hypochlorite disinfection on MRSA rates A. Mahamat, F. MacKenzie, K. Brooker, D. Monnet, J. Daur`es, I. Gould (Nimes, FR; Aberdeen, Elgin, UK; Copenhagen, DK) Objectives: MRSA rates in a hospital in the North-East of Scotland were significantly declining due to a series of infection control interventions.
S6 These included terminal disinfection of the environment in isolation rooms and cohort areas by application of 1:1000 sodium hypochlorite in place of detergent (ECCMID ’06, abstract P1333). We evaluated the effect of replacing sodium hypochlorite with a standard detergent. Methods: From January 1997 to May 2006, monthly percentage, nonduplicate S. aureus clinical cases caused by MRSA were collated. In February 2005 hypochlorite cleaning solution as replaced by a standard detergent. Other infection control measures remained unchanged. Dynamic regression analysis with linear transfer functions and interrupted time-series analyses were used to estimate the effect to the intervention. Results: Previously, MRSA rates wee successfully reduced due to environmental screening (p = 0.03), use of hypochlorite for environmental disinfection (p = 0.002), use of alcohol based hand disinfection (p = 0.03) and patient admission screening (p < 0.01). Stopping the hypochlorite disinfection was associated with a sudden increase in clinical cases of MRSA from 10 to 25% over a 6 month period (p = 0.03), with levels approaching those seen prior to the start of the infection control programme in 2001 (see figure). Conclusions: Stopping hypochlorite environmental disinfection was strongly associated with an increase in clinical MRSA cases. This work adds significantly to the meagre published evidence that environmental contamination is important in the spread of MRSA.
Resistance surveillance O24 Multi-drug resistant enterococci among Portuguese swine after growth promoter ban C. Novais, A. Freitas, T.M. Coque, J.C. Sousa, L. Peixe (Porto, PT; Madrid, ES) Objectives: To determine antibiotic-resistant enterococci in Portuguese piggery samples and to analyse antibiotic resistance genes among these strains after European growth promoter ban. Methods: Samples from waste treatment and dry faeces from 2 pig farms in the South of Portugal were studied during 2006. Samples were plated onto selective Slanetz-Bartley agar with or without antibiotics. Bacterial identification was performed by both standard biochemical profiles and amplification of species specific genes. Antibiotic susceptibility (12 antibiotics) was determined by disk diffusion method (CLSI). Detection of genes coding for resistance [vanA, B, C1, C2, ermA, B, C, tetM, L, O, K, S, aac(6 )-Ie-aph(2 )Ia, aph(2 )-Ib,Ic,Id, aph(3 )-IIIa, vat E] were searched by PCR. Results: We identified 84 enterococci (9 E. faecalis, 17 E. faecium, 1 E. gallinarum, 2 E. casseliflavus and 55 Enterococcus spp.). Most isolates showed decreased susceptibility to tetracycline, minocycline, erythromycin, and quinupristin-dalfopristin (95%, 94%, 80%, 54%, respectively), and to a lesser extent to high-level of resistance (HLR) of streptomycin, nitrofurantoin, ciprofloxacin, HLR to gentamicin, chloramphenicol and ampicillin (52%, 33%, 32%, 21%, 11%, 10%). All were susceptible to glycopeptides. Non-susceptible isolates to tetracyclines, aminoglycosides and macrolides contained tetM (55%),
17th ECCMID / 25th ICC, Oral presentations tetL (54%), tetM+tetL (32%), tetS (5%), aac(6 )-Ie-aph(2 )-Ia (89%), aac(6 )-Ie-aph(2 )-Ia+aph(3 )-IIIa (47%), ermB (49%). vanC1 was linked to E. gallinarum, and vanC2 to E. casseliflavus as expected. Conclusions: Although all growth promoters were progressively removed from EU in the course of the last 10 years, antibiotic multiresistant enterococci were isolated in Portuguese piggeries. Whether persistence of these antibiotic resistant strains is due to selection by antibiotics or other agents deserves further studies. O25 Experiences and results from the surveillance programme of resistance in feed, food and animals in Norway (NORM-VET) 2000–2005 M. Norstr¨om, H. Tharaldsen, M. Sunde (Oslo, NO) Objectives: The monitoring programme for antimicrobial resistance in the veterinary and food production sectors (NORM-VET) was established in 2000. The goals of the programme are to monitor the antimicrobial resistance situation in feed, food and animals over time, in relation to the human situation and to the resistance situation in other countries. Data from NORM-VET could form a basis for risk assessments and be a tool for targeting interventions and further to evaluate the effectiveness of such interventions. This study was performed to summarise the experiences and results obtained during the first six years of the programme. Methods: The zoonotic agents Salmonella (from feed, animals and food) and Campylobacter jejuni (from broiler and broiler meat) were monitored annually. E. coli and Enterococcus spp. (indicator bacteria) were sampled from various animal species and meat products biannually. Specific clinical isolates from the routine diagnostic have been included biannually. The isolates have mainly been tested using a microdilution technique (VetMICTM). The minimum inhibitory concentrations were recorded and analysed in WHONET 5.3. For the categorising of the isolates as resistant or susceptible epidemiological cut-off values were applied. Results: The occurrence of resistance in the monitored species and products is in an international perspective low and the results from the first six years of the programme show that the situation is stable. Conclusion: Evaluation of the first six years of the programme has recognized that the relatively low number of isolates of each species and source included complicates the conclusions possible to draw from the data, especially evaluating trends over time. Even though the run costs of the programme has been limited to a minimum, it is still useful for the purpose of monitoring antimicrobial resistance within a country as Norway, where the resistance problem in the animal and food sectors still is at a very low level. It also consists as valuable source for further research of antimicrobial resistance mechanisms and development. However, the use of this source to perform risk assessments is limited as there still is a lack of even more specific data as for instance data on usage at animal or farm level. O26 Comparison of antibiotic susceptibilities of Staphylococcus aureus and S. intermedius isolates from dog owners and their dogs M. Boost, S. Lai, D. Ko, M. O’Donoghue (Kowloon, HK) Objectives: Antibiotic resistance in veterinary isolates has been reported to be higher than in human isolates due to frequent empirical use, and there are concerns about transfer of resistance between staphylococcal species. S. intermedius is the more common colonising species in dogs, but S. aureus, including MRSA, may also be present. Case reports suggest there can be cross-infection between companion animals and man. Increasing concern about MRSA in the community has led to recommendations for surveillance of antibiotic resistance in isolates from companion animals. This study compared antibiotic resistance in isolates of S. aureus and S. intermedius from dogs and their owners. Methods: A cross-sectional study of owners and their dogs was performed using a convenience sample of 800 pairs recruited at six veterinary practices. Nasal swabs were collected from both owner and