- Email: [email protected]
Contamination of intubating stylets in operating rooms
Letters to the Editor / Journal of Hospital Infection 75 (2010) 325–337 Table I Logistic regression analysis of risk factors for fatal outcome following Gram-positive bacteraemia B
Wald
P
OR
95% CI
c2 Neonatal age Immunosuppression status Malnutrition Life-threatening underlying condition Recent surgery Growth of vancomycinresistant staphylococci Sex
3.186 4.297
15.071 10.902
<0.001 0.001
24.19 73.49
4.84–120.81 5.73–941.93
4.215 3.969
13.779 15.550
<0.001 <0.001
67.68 52.95
7.31–626.58 7.36–380.74
1.753 2.018
5.338 6.110
0.021 0.013
5.77 7.53
1.31–25.54 1.52–37.29
0.627
0.918
0.338
1.87
0.52–6.75
B, logistic regression coefficient; OR, odds ratio; CI, confidence interval.
antibiotic treatment, human immunodeficiency virus infection, other underlying infectious diseases, malnutrition, and bloodstream infection caused by Gram-negative bacteria and Candida spp.5 Our study suggests that the pattern of Gram-positive bacteraemia, and staphylococcus bacteraemia in particular, in children is consistent with that previously reported to be associated with MRSA bacteraemia in adults. Conflict of interest statement None declared. Funding sources None. References 1. Woodford N. Biological counterstrike: antibiotic resistance mechanisms of Gram-positive cocci. Clin Microbiol Infect 2005;3:2–21. 2. Clinical and Laboratory Standards Institute. M7-A7: methods for dilution antimicrobial susceptibility tests for bacteria that grow aerobically, approved standard – seventh edition. Wayne, PA: Clinical and Laboratory Standards Institute; 2006. 3. Venkatesh MP, Placencia F, Weisman LE. Coagulase-negative staphylococcal infections in the neonate and child: an update. Semin Pediatr Infect Dis 2006;17:120–127. 4. Miller NS, Dobre MC, Liebschutz JM, Williams TC, Orr BL, Farber HW. Micrococcus bacteremia in a patient with pulmonary hypertension and a long-term central venous catheter: opportunity knocks, and an unexpected pathogen enters. Clin Microbiol Newslett 2007;29:173–175. 5. Blomberg B, Manji KP, Urassa WK, et al. Antimicrobial resistance predicts death in Tanzanian children with bloodstream infections: a prospective cohort study. BMC Infect Dis 2007;7:43–56.
M. El Sayed Zakia,* A.A.A. El-Azizb T. El-Said El-Bannab W.S.A. Sallamc a Mansoura University, Mansoura University Children’s Hospital, Mansoura, Egypt b Faculty of Pharmacy, Tanta University, Tanta, Egypt c Mansoura University Hospital, Mansoura, Egypt * Corresponding author. Address: Clinical Microbiology Laboratories, Mansoura University Children’s Hospital, Mansoura, Egypt. Tel.: þ205 02258877; fax: þ205 02234767. E-mail address: [email protected] (M. El Sayed Zaki) Available online 04 May 2010 Ó 2010 The Hospital Infection Society. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.jhin.2010.01.031
331
Contamination of intubating stylets in operating rooms Madam, An intubating stylet is semicritical equipment due to mucous membrane contact.1,2 Intubating stylets are reused in some hospitals; therefore, the processes of decontamination and storage are important, because contaminated stylets may introduce pathogens and cause patient complications. The Center for Disease Control and Environmental Protection (CDC) recommends, at least, a high level disinfection process by using high potency disinfectants for semicritical equipment.1–4 In Songklanagarind University Hospital, decontamination of intubating stylets is carried out using intermediate level disinfection, thus not in conformity with the CDC recommendation. We conducted a cross-sectional study between between March and September 2009 to identify the incidence of contamination of intubating stylets and to evaluate the effectiveness of the decontamination process for intubating stylets in operating rooms. We collected 91 specimens from 57 intubating stylets in 18 operating rooms both during and outside working hours. No advance notice was given to anaesthetic personnel. All of the stylets were sterilised with 4% chlorhexidine scrub or 7.5% povidone-iodine scrub, followed by wiping with 70% alcohol solution, and were kept in open containers. All sample tips were swabbed and cultured by one researcher. All swabs were cultured on blood agar for bacteria and fungi, and MacConkey agar for Gram-negative bacteria. All plates were incubated at 37 C for two days. The results were reported as positive (normal flora or pathogenic organism) or negative. If the results were positive, the containers that contained these intubating stylets were also swabbed for culture. Eight (8.8%) of the 91 intubating stylets from operating rooms yielded positive cultures (95% confidence interval: 3.8–16.6). Positive culture results by operating rooms are shown in Table I. The results of the container cultures from these rooms were similar to the results of the intubating stylet cultures. Positive cultures were found on Monday more than any other day. The incidence of contamination of intubating stylets in our study was lower than the incidence of contamination of laryngoscope blades after intermediate level disinfection.5,6 Most of the contamination of intubating stylets was with pathogenic bacteria and fungi. The strength of this study was the fact that one researcher did all the sample collection and the results can be used for the development of an infection control policy. From our result, the storage might be the process that resulted in the contamination of intubating stylets because of the same positive culture results
Table I Positive culture results by operating rooms Operating room
Emergency Orthopaedic Remote Ear, nose, and throat
Intubating stylet, N (%)
Total
No growth
Pseudomonas aeruginosa
MRSA
MSSA
Yeast
24 (96) 4 (66) 4 (80)
– 1 (16) –
– 1 (16) –
1 (4) – –
–
–
– – 1 (20) –
0 (0)
4 (100)
25 6 5 4
MRSA, meticillin-resistant Staphylococcus aureus; MSSA, meticillin-sensitive S. aureus.
332
Letters to the Editor / Journal of Hospital Infection 75 (2010) 325–337
from the containers and from the intubating stylets. However, one limitation of our study was that we did not evaluate the cleaning process. In summary, the disinfection and storage techniques that are routinely used at Songklanagarind Hospital were not effective; thus, changing the decontamination methods should be considered in order to improve the standard of practice. Acknowledgements We thank Miss N. Ingwiya of the Department of Pathology for assistance in microbial testing, Mr E. McNeil of the Epidemiology Unit for assistance in data analysis and editorial guidance, and Mr E. Subashi of the International Affairs Unit for editorial guidance. Conflict of interest statement None declared. Funding sources Faculty of Medicine, Prince of Songkla University, Hat Yai, Songkhla, Thailand. References 1. Rutala WA. APIC guideline for selection and use of disinfectants. Am J Infect Control 1996;24:313–342. 2. Rutala WA, Weber DJ. Infection control: the role of disinfection and sterilization. J Hosp Infect 1999;43(Suppl.):S43–55. 3. Rutala WA, Weber DJ. Guideline for disinfection and sterilization of prion-contaminated medical instruments. Infect Control Hosp Epidemiol 2010;31: 107–117. 4. Association of Anaesthesia of Great Britain and Ireland. Infection control in anaesthesia. Anaesthesia 2008;63:1027–1036. 5. Boonmak P, Boonmak S, Chau W, Mukumporn T. The incidence of microbial contamination in anesthetic equipments at Srinagarind Hospital. Thai J Anesthesiol 2003;29:24–32. 6. Zinboonyahgoon N, Chinachoti T, Trakulsomboon S, Plicharoenpon P. Contamination of laryngoscopes in Siriraj Hospital’s operating theaters. Thai J Anesthesiol 2008;34:85–91.
C. Sriparkdeea P. Rujirojindakula,* J. Pakpiroma C. Prechawaia S. Karnnauwakunb A. Chantarokorna a Department of Anaesthesiology, Faculty of Medicine, Prince of Songkla University, Hat Yai, Songkhla, Thailand b
*
Department of Pathology, Faculty of Medicine, Prince of Songkla University, Hat Yai, Songkhla, Thailand Corresponding author. Address: Department of Anaesthesiology, Faculty of Medicine, Prince of Songkla University, Hat Yai, Songkhla 90110, Thailand. Tel.: þ66 74 451 651; fax: þ66 74 429 621. E-mail address: [email protected] (P. Rujirojindakul) Available online 19 June 2010
Ó 2010 The Hospital Infection Society. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.jhin.2010.04.002
Active warming systems to maintain perioperative normothermia in hip replacement surgery
Madam, In response to Moretti et al.’s article ‘Active warming systems to maintain perioperative normothermia in hip replacement surgery: a therapeutic aid or a vector of infection?’, the National Institutes of Health (NIH) used computational fluid dynamics (CFD) and particle-tracking methodology to assess whether a forced-air patient-warming system increases the risk of nosocomial infections at the surgical wound site.1 NIH analysed laminar airflow disruption and room airflow patterns to determine the effect of squame impingement from personnel surrounding the operating table as a source of surgical wound infection. The literature indicates that a forced-air warmer system may disturb the operating room laminar airflow and increase the risk of nosocomial infections. Memarzadeh et al. used advanced numerical modelling and empirical data to evaluate the effects of room parameters on minimising surgical site contamination risk from specific particulate sources.2,3 Their work shows that <1% of particles hitting the surgical site from the anaesthesiologist location are due to the relative dominance of the thermal plume caused by the surgical site.3 Using colony-counting methodology to determine settling of squames on the surgical site, Moretti et al. concluded that the body-warming system does not pose a risk of nosocomial infections and that the increased bacterial load found after application of a body warming system is comparable to, or lower than, the load present at the time of placement of the patient on the operating table.1 Memarzadeh explains that turbulent airflow in a ventilated room transports the squames by both airflow convection and turbulent diffusion. The influence of the squames' motions and temperatures on the fluid flow parameters is negligible because squames are sufficiently light and their volume flow rate is substantially lower than those of the fluid stream. The distributions of air velocities and the turbulent parameters from the CFD simulation output are directly applied to predict the path of the airborne squames in convection and diffusion processes. The particle motion in the air obeys an equation, as described further in our full publication. The NIH analysis includes heat-generating factors and ventilation factors. The air supply temperature was determined by the average room air temperature (70 F) assuming 15 and 20 air changes per hour (ACH). NIH made observations with the air warmer on and off compared with two ventilation flow rates. The squames are 25 mm by 3–5 mm thick. Approximately 30 000 total squames were released from the head and arms of the anaesthesiologist location and tracked for 1 h. The number of squames deposited on the patient surface was compared for both scenarios. Simulation results of flow fields and particle tracking show velocity plots at the vertical plane cutting through the centre of the operating table with 20 ACH for the two scenarios. Flow patterns in both plots are similar except that the downward velocity from ceiling laminar diffuser is slightly less strong with the forced-air warmer operating than when the air warmer is off. Similar flow patterns are observed 1 h after the squames are released from the sources. Since the operating air warmer system adds hot air but also dissipates heat to the region around the bed, the air temperature is apparently higher than when the air warmer is off. The squame plots show that particles are cleaned away from the patient by the airflow from the laminar diffuser no matter if the forced air warmer is on or off. The percentage of squames deposited on the patient was zero both when the forced air warmer was on or off. The percentage of squames
Wald
P
OR
95% CI
c2 Neonatal age Immunosuppression status Malnutrition Life-threatening underlying condition Recent surgery Growth of vancomycinresistant staphylococci Sex
3.186 4.297
15.071 10.902
<0.001 0.001
24.19 73.49
4.84–120.81 5.73–941.93
4.215 3.969
13.779 15.550
<0.001 <0.001
67.68 52.95
7.31–626.58 7.36–380.74
1.753 2.018
5.338 6.110
0.021 0.013
5.77 7.53
1.31–25.54 1.52–37.29
0.627
0.918
0.338
1.87
0.52–6.75
B, logistic regression coefficient; OR, odds ratio; CI, confidence interval.
antibiotic treatment, human immunodeficiency virus infection, other underlying infectious diseases, malnutrition, and bloodstream infection caused by Gram-negative bacteria and Candida spp.5 Our study suggests that the pattern of Gram-positive bacteraemia, and staphylococcus bacteraemia in particular, in children is consistent with that previously reported to be associated with MRSA bacteraemia in adults. Conflict of interest statement None declared. Funding sources None. References 1. Woodford N. Biological counterstrike: antibiotic resistance mechanisms of Gram-positive cocci. Clin Microbiol Infect 2005;3:2–21. 2. Clinical and Laboratory Standards Institute. M7-A7: methods for dilution antimicrobial susceptibility tests for bacteria that grow aerobically, approved standard – seventh edition. Wayne, PA: Clinical and Laboratory Standards Institute; 2006. 3. Venkatesh MP, Placencia F, Weisman LE. Coagulase-negative staphylococcal infections in the neonate and child: an update. Semin Pediatr Infect Dis 2006;17:120–127. 4. Miller NS, Dobre MC, Liebschutz JM, Williams TC, Orr BL, Farber HW. Micrococcus bacteremia in a patient with pulmonary hypertension and a long-term central venous catheter: opportunity knocks, and an unexpected pathogen enters. Clin Microbiol Newslett 2007;29:173–175. 5. Blomberg B, Manji KP, Urassa WK, et al. Antimicrobial resistance predicts death in Tanzanian children with bloodstream infections: a prospective cohort study. BMC Infect Dis 2007;7:43–56.
M. El Sayed Zakia,* A.A.A. El-Azizb T. El-Said El-Bannab W.S.A. Sallamc a Mansoura University, Mansoura University Children’s Hospital, Mansoura, Egypt b Faculty of Pharmacy, Tanta University, Tanta, Egypt c Mansoura University Hospital, Mansoura, Egypt * Corresponding author. Address: Clinical Microbiology Laboratories, Mansoura University Children’s Hospital, Mansoura, Egypt. Tel.: þ205 02258877; fax: þ205 02234767. E-mail address: [email protected] (M. El Sayed Zaki) Available online 04 May 2010 Ó 2010 The Hospital Infection Society. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.jhin.2010.01.031
331
Contamination of intubating stylets in operating rooms Madam, An intubating stylet is semicritical equipment due to mucous membrane contact.1,2 Intubating stylets are reused in some hospitals; therefore, the processes of decontamination and storage are important, because contaminated stylets may introduce pathogens and cause patient complications. The Center for Disease Control and Environmental Protection (CDC) recommends, at least, a high level disinfection process by using high potency disinfectants for semicritical equipment.1–4 In Songklanagarind University Hospital, decontamination of intubating stylets is carried out using intermediate level disinfection, thus not in conformity with the CDC recommendation. We conducted a cross-sectional study between between March and September 2009 to identify the incidence of contamination of intubating stylets and to evaluate the effectiveness of the decontamination process for intubating stylets in operating rooms. We collected 91 specimens from 57 intubating stylets in 18 operating rooms both during and outside working hours. No advance notice was given to anaesthetic personnel. All of the stylets were sterilised with 4% chlorhexidine scrub or 7.5% povidone-iodine scrub, followed by wiping with 70% alcohol solution, and were kept in open containers. All sample tips were swabbed and cultured by one researcher. All swabs were cultured on blood agar for bacteria and fungi, and MacConkey agar for Gram-negative bacteria. All plates were incubated at 37 C for two days. The results were reported as positive (normal flora or pathogenic organism) or negative. If the results were positive, the containers that contained these intubating stylets were also swabbed for culture. Eight (8.8%) of the 91 intubating stylets from operating rooms yielded positive cultures (95% confidence interval: 3.8–16.6). Positive culture results by operating rooms are shown in Table I. The results of the container cultures from these rooms were similar to the results of the intubating stylet cultures. Positive cultures were found on Monday more than any other day. The incidence of contamination of intubating stylets in our study was lower than the incidence of contamination of laryngoscope blades after intermediate level disinfection.5,6 Most of the contamination of intubating stylets was with pathogenic bacteria and fungi. The strength of this study was the fact that one researcher did all the sample collection and the results can be used for the development of an infection control policy. From our result, the storage might be the process that resulted in the contamination of intubating stylets because of the same positive culture results
Table I Positive culture results by operating rooms Operating room
Emergency Orthopaedic Remote Ear, nose, and throat
Intubating stylet, N (%)
Total
No growth
Pseudomonas aeruginosa
MRSA
MSSA
Yeast
24 (96) 4 (66) 4 (80)
– 1 (16) –
– 1 (16) –
1 (4) – –
–
–
– – 1 (20) –
0 (0)
4 (100)
25 6 5 4
MRSA, meticillin-resistant Staphylococcus aureus; MSSA, meticillin-sensitive S. aureus.
332
Letters to the Editor / Journal of Hospital Infection 75 (2010) 325–337
from the containers and from the intubating stylets. However, one limitation of our study was that we did not evaluate the cleaning process. In summary, the disinfection and storage techniques that are routinely used at Songklanagarind Hospital were not effective; thus, changing the decontamination methods should be considered in order to improve the standard of practice. Acknowledgements We thank Miss N. Ingwiya of the Department of Pathology for assistance in microbial testing, Mr E. McNeil of the Epidemiology Unit for assistance in data analysis and editorial guidance, and Mr E. Subashi of the International Affairs Unit for editorial guidance. Conflict of interest statement None declared. Funding sources Faculty of Medicine, Prince of Songkla University, Hat Yai, Songkhla, Thailand. References 1. Rutala WA. APIC guideline for selection and use of disinfectants. Am J Infect Control 1996;24:313–342. 2. Rutala WA, Weber DJ. Infection control: the role of disinfection and sterilization. J Hosp Infect 1999;43(Suppl.):S43–55. 3. Rutala WA, Weber DJ. Guideline for disinfection and sterilization of prion-contaminated medical instruments. Infect Control Hosp Epidemiol 2010;31: 107–117. 4. Association of Anaesthesia of Great Britain and Ireland. Infection control in anaesthesia. Anaesthesia 2008;63:1027–1036. 5. Boonmak P, Boonmak S, Chau W, Mukumporn T. The incidence of microbial contamination in anesthetic equipments at Srinagarind Hospital. Thai J Anesthesiol 2003;29:24–32. 6. Zinboonyahgoon N, Chinachoti T, Trakulsomboon S, Plicharoenpon P. Contamination of laryngoscopes in Siriraj Hospital’s operating theaters. Thai J Anesthesiol 2008;34:85–91.
C. Sriparkdeea P. Rujirojindakula,* J. Pakpiroma C. Prechawaia S. Karnnauwakunb A. Chantarokorna a Department of Anaesthesiology, Faculty of Medicine, Prince of Songkla University, Hat Yai, Songkhla, Thailand b
*
Department of Pathology, Faculty of Medicine, Prince of Songkla University, Hat Yai, Songkhla, Thailand Corresponding author. Address: Department of Anaesthesiology, Faculty of Medicine, Prince of Songkla University, Hat Yai, Songkhla 90110, Thailand. Tel.: þ66 74 451 651; fax: þ66 74 429 621. E-mail address: [email protected] (P. Rujirojindakul) Available online 19 June 2010
Ó 2010 The Hospital Infection Society. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.jhin.2010.04.002
Active warming systems to maintain perioperative normothermia in hip replacement surgery
Madam, In response to Moretti et al.’s article ‘Active warming systems to maintain perioperative normothermia in hip replacement surgery: a therapeutic aid or a vector of infection?’, the National Institutes of Health (NIH) used computational fluid dynamics (CFD) and particle-tracking methodology to assess whether a forced-air patient-warming system increases the risk of nosocomial infections at the surgical wound site.1 NIH analysed laminar airflow disruption and room airflow patterns to determine the effect of squame impingement from personnel surrounding the operating table as a source of surgical wound infection. The literature indicates that a forced-air warmer system may disturb the operating room laminar airflow and increase the risk of nosocomial infections. Memarzadeh et al. used advanced numerical modelling and empirical data to evaluate the effects of room parameters on minimising surgical site contamination risk from specific particulate sources.2,3 Their work shows that <1% of particles hitting the surgical site from the anaesthesiologist location are due to the relative dominance of the thermal plume caused by the surgical site.3 Using colony-counting methodology to determine settling of squames on the surgical site, Moretti et al. concluded that the body-warming system does not pose a risk of nosocomial infections and that the increased bacterial load found after application of a body warming system is comparable to, or lower than, the load present at the time of placement of the patient on the operating table.1 Memarzadeh explains that turbulent airflow in a ventilated room transports the squames by both airflow convection and turbulent diffusion. The influence of the squames' motions and temperatures on the fluid flow parameters is negligible because squames are sufficiently light and their volume flow rate is substantially lower than those of the fluid stream. The distributions of air velocities and the turbulent parameters from the CFD simulation output are directly applied to predict the path of the airborne squames in convection and diffusion processes. The particle motion in the air obeys an equation, as described further in our full publication. The NIH analysis includes heat-generating factors and ventilation factors. The air supply temperature was determined by the average room air temperature (70 F) assuming 15 and 20 air changes per hour (ACH). NIH made observations with the air warmer on and off compared with two ventilation flow rates. The squames are 25 mm by 3–5 mm thick. Approximately 30 000 total squames were released from the head and arms of the anaesthesiologist location and tracked for 1 h. The number of squames deposited on the patient surface was compared for both scenarios. Simulation results of flow fields and particle tracking show velocity plots at the vertical plane cutting through the centre of the operating table with 20 ACH for the two scenarios. Flow patterns in both plots are similar except that the downward velocity from ceiling laminar diffuser is slightly less strong with the forced-air warmer operating than when the air warmer is off. Similar flow patterns are observed 1 h after the squames are released from the sources. Since the operating air warmer system adds hot air but also dissipates heat to the region around the bed, the air temperature is apparently higher than when the air warmer is off. The squame plots show that particles are cleaned away from the patient by the airflow from the laminar diffuser no matter if the forced air warmer is on or off. The percentage of squames deposited on the patient was zero both when the forced air warmer was on or off. The percentage of squames