CONTAGIOUS COMMENTS Department of Epidemiology

Transcription

1 VOLUME XXVII NUMBER 6 July 2012 CONTAGIOUS COMMENTS Department of Epidemiology Bugs and Drugs Elaine B. Dowell SM, MLS (ASCP); Sarah K. Parker, MD; James K. Todd, MD Each year the Children s Hospital Colorado Microbiology Laboratory publishes our previous year s cumulative antimicrobial susceptibility test data according to the Clinical Laboratory Standard Institute (CLSI) guidelines. We would like to share some of these guidelines. The cumulative antibiogram is to be published at least annually. Only final verified results that are appropriate diagnostically are included. Surveillance cultures are excluded from the data. We only report data from species with >30 isolates with few exceptions. If fewer than 30 isolates are available, a determination is made to assess whether the data is essential. If so, a note is included to indicate that the data has less statistical validity. Alternatively, we consider analyzing data from a longer time frame, such as 2 or 3 years. Elimination of duplicates is encouraged with emphasis on the first isolate of a species per patient per analysis period irrespective of body site. Only antimicrobials that are routinely reported are included in the antibiogram. Supplemental testing for resistant isolates may be available by calling the Micro Lab x Streptococcus pneumoniae susceptibilities are reported with two interpretations for Cefotaxime and Penicillin according to the site of infection, meningeal and non-meningeal, to indicate the need for higher levels of antimicrobial for cases with meningeal involvement. The antimicrobial that is specifically used in the analytical testing process is reported. In many instances, additional antimicrobials may be directly inferred from this information. This year, we have added some of these agents into our charts to typical usage patterns at Children s. MRSA Graph: The number of MRSA isolates recovered from blood continues to decline as the overall rates of MRSA isolations level off. We have recovered no Staphylococcus aureus isolates showing Vancomycin resistance. Table 2 S. pneumoniae isolates continue to trend toward decreased resistance (they are more susceptible). We have serotyped twenty-two systemic S. pneumoniae isolates and they represent a broad distribution including fourteen different serotypes, with 19A and 22F being the most prevalent. Our Viridans streptococcus isolates continue a trend of increased resistance. Six new vancomycin resistant enterococcus (VRE) patients were identified in our patient population, which is an increase from 2 in Table 4 Addition of a urine isolate table proved to be helpful in the 2010 antibiogram and so we will continue to separate this data. Numbers of urine isolates continue to increase. Pseudomonas aeruginosa was added to the chart this year. ESBL isolates continue to be found predominantly in E. coli isolated from urine, of which there were 20 in these data. Patients with ESBL-producing organisms isolated from urine who have an uncomplicated UTI may respond to therapy with beta-lactam agents despite the recovery of these resistant organisms in culture, particularly if with combined with a beta-lactamase inhibitor. This is due to the concentration of antimicrobial well above the MIC at the site of infection. Table 5 Achromobacter spp. has been added to the nonenterobacteriaceae table. Stenotrophomonas maltophilla shows a significant increase in resistance to Trimethoprim/Sulfamethoxazole. Ciprofloxacin will be the quinolone antimicrobial tested and reported for Pseudomonas aeruginosa in 2012 due to its greater effectiveness. Table 6 A single Fluconazole resistant C. albicans was isolated in a patient this year, but the patient had been on fluconazole prophylaxis. Species included in the chart data are listed. Table 7 This table is included from the CLSI document as information for clinicians; these isolates were not recovered from Children s patients. There were sufficient Children's Hospital Colorado isolates of P. acnes to report our data and these are included in the chart. VOLUME XXVII NUMBER 6 July 2012 Page 1

2 Changes affecting our data reporting for 2012 In 2012, we have updated our carbapenem breakpoints for enterobacteriaceae and they are currently consistent with CLSI guidelines. These new breakpoints are lower and we are currently reporting more resistance. This change has been made in order to eliminate the need for supplemental testing in order to detect carbapenemase producing organisms, which is difficult to perform and interpret in the lab. We have also added ampicillin/sulbactam for E. coli isolated from urine as this is an antimicrobial referenced in our practice guidelines. For additional information, the Bugs and Drugs handbook is located on Planet TCH by following the link: pdf If you work within the hospital and would like to have your own personal hard copy, please call the Micro Lab at and we will send you one. If you are an external client and would like a hard copy, please call Carolyn Brock at and we will mail you a copy. VOLUME XXVII NUMBER 6 July 2012 Page 2

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5 We are modifying our distribution process for Contagious Comments. If you wish to receive this publication please provide us with your address below. Name: Address: Both the Contagious Comments and Bug Watch publications are always posted on Children s Hospital Colorado website at: Please return your address to: Carolyn Brock, Children s Hospital Colorado, Epidemiology Box B276, E. 16 th Avenue, Aurora, CO or address: carolyn.brock@childrenscolorado.org. Thank you for your interest in our publication. CONTAGIOUS COMMENTS Department of Epidemiology EDITOR: Carolyn Brock, Program Assistant Children s Hospital Colorado, Dept. of Epidemiology, B E. 16th Avenue, Aurora, CO Phone: (720) ; FAX: (720) carolyn.brock@childrenscolorado.org ** We Recycle! ** VOLUME XXVII NUMBER 6 July 2012 Page 5