York Chairman David B. Jones, MD

Transcription

1 York Chairman David B. Jones, MD Pathologists Abby W. Davis, MD David A. Derrick, MD J. Ander Pindzola, MD John A. Wright, MD Stanley D. Hurtt, MD Matthew F. Georgy, MD Michelle L. Erickson, MD, MBA William M. Taylor, MD Pathologists' Assistants Mandi L. Howell, MS Janine A. Riben, MHS Fred J. Faust, Sr., MS Jennifer L. Fuhrman, MS Clinical Chemist Stephen M. Manzella, PhD. Editor Clinical Microbiologist Arthur E. Crist, Jr., PhD Administrative Director Martin L. Beaverson, MT Operations Manager Tina M. Stover, MT Gettysburg Pathologist Angela Brooks, MD Administrative Director David W. Meeder, MT, MBA THERAPEUTIC PHLEBOTOMY CHANGE Julie Hicks, Supervisor, Blood Resources Therapeutic phlebotomy (the removal 500 ml of blood) is typically an outpatient procedure performed by Blood Resources at Apple Hill Medical Center for the treatment of: polycythemia, hemochromatosis, porphyria cutanea tarda, erythrocytosis or myeloproliferative disease. One of the WellSpan York Hospital Laboratory regulatory agencies now requires the Blood Bank Medical Director (or her designee) to review and approve: the indications for a therapeutic phlebotomy, the therapeutic goal of the phlebotomy, the treatment plan and the patient s record prior to the therapeutic phlebotomy. Because of this change and the time needed to perform this review, Blood Resources is requesting all ordering physicians offices to fax the order for therapeutic phlebotomy to Blood Resources prior to or at the time of scheduling the patient for the procedure. Blood Resources has revised and is distributing a new therapeutic phlebotomy order form to all physicians who currently order therapeutic phlebotomies. The new form is completed by filling in the blanks or checking the appropriate boxes for the required information. This new form and the new review process is effective 11/1/11. Please be sure to inform this issue Therapeutic Phlebotomy Change P. 1 My Patient Has An Antibody? Now What? P. 2 Herpes Simplex Type 1 & 2 Detection & Typing P Antibiograms P. 4 Laboratory Services Bulletin [March 2012, Vol. 42. No. 1] 1

2 any affected office staff of the change. This is a substantial change for all those involved in ordering and performing therapeutic phlebotomies and Blood Resources wishes to thank you for your cooperation and patience in making this transition. If there are any questions regarding this change, please call (717) Physicians using WellSpan Gettysburg Hospital for therapeutic phlebotomies should contact Margaret Nicastro, Outpatient (717) MY PATIENT HAS AN ANTIBODY? NOW WHAT? Barbara Steiber, MT (ASCP), Clinical Instructor-Immunohematology For the clinician, the notification from the Transfusion Service that one s patient has an alloantibody means one thing: there is going to be a delay in providing red blood cell products for that patient. The good news is that this problem will not, in most cases, delay the transfusion of other blood components such as platelets, plasma and cryoprecipitate. The bad news, and this is critical to understand, is that in these cases O negative red blood cells are NOT the universal donor and may NOT be safe to transfuse until the problem has been resolved. This often raises the question of how or why did the patient make the antibody and is this preventable? Patients may make antibodies to red blood cell antigens following exposure to foreign RBC antigens via transfusion, pregnancy or even sharing needles when injecting IV drugs; however, some antibodies can be made with no documented exposure. Patients can make antibodies to their own red blood cells as in autoimmune hemolytic anemia. Some medications can cause a patient to exhibit apparent antibodies to red blood cells. In this discussion, only alloantibodies will be addressed. The percentage of patients who have antibodies varies with the category of patient that the clinician encounters. A population of chronically transfused patients will have a higher probability than an acutely transfused patient population simply because the former are exposed repeatedly over time. For example, oncology and sickle cell patients are much more likely to present with antibodies than a trauma patient. Is the formation of alloantibodies preventable? In most cases, it is not. It would be cost prohibitive and extremely time consuming to provide phenotypically matched red blood cells to all patients. This is only done for selected patient populations such as those with sickle cell disease. For the transfusion service Clinical Laboratory Scientist, the detection of one or multiple alloantibodies in a patient s plasma indicates that more time, testing and resources will be required to supply a product that is safe to transfuse. The presence of alloantibody is first suspected when evaluating the results of the antibody screen. This a qualitative test performed on all pretransfusion specimens. If the screening test is negative, it is generally safe to select ABO/Rh compatible red cell units for transfusion (see chart). Acceptable ABO/Rh options when no antibodies are present. Laboratory Services Bulletin [March 2012, Vol. 42. No. 1] 2

3 If the screening test is positive, it alerts the scientist that one or more antibodies are present. The next step is to identify the specificity of the antibody or antibodies so that antigen negative, compatible red blood cells may be selected and crossmatched for the patient. The process of antibody identification is not a standardized test where one size fits all. Each patient s problem is unique and many variables are involved which will determine how easy or difficult it will be to solve the puzzle. Is the antibody new onset or has the patient exhibited this previously? Is there a single antibody or multiple antibodies? What is the frequency of distribution of the corresponding antigens in the population of donors? Which tests and techniques must be employed to discern the answer to the mystery? How much time and what reagents are needed? What is the probability that the necessary units will be found in the current inventory? Will units have to be obtained from the rare donor population and imported to our facility? These variables can result in a solution that requires a simple, straightforward workup taking an hour or two, or one that requires several hours or even days to solve. Fortunately, the latter is the exception, not the rule. If the antibody is a previously identified problem, obviously the delay will be shorter than if a new antibody is detected. If a patient has a positive antibody screen, a footnote will be added to alert the clinician that there will be a delay in providing red blood cells. Another point to remember is that the presence of a single antibody does not equate to having blood available more quickly than the presence of multiple antibodies. The patient with multiple antibodies may require a lengthy and more extensive identification process, but if the corresponding antigens are lower in frequency, it will be easier to find compatible units. An example would be the presence of anti-kell and anti- E. The patient has two antibodies but approximately 65-70% of the Rh positive and 90% of the Rh negative population will be compatible. Therefore, the delay in transfusion will be minimal. Conversely, for a patient with a single antibody to a very high frequency antigen, it will be more difficult to find compatible units. An example of this scenario would be a patient with anti-k (Cellano). There is only one antibody but 99+% of the population carries that antigen on their red blood cells and units would have to be obtained from the rare donor supply, probably frozen units that would require extra processing before they are ready to transfuse. At the Wellspan Transfusion Services, a dedicated and experienced staff of pathologists and clinical laboratory scientists work together with the clinicians and nursing staff to provide safe, compatible blood products for all who require transfusion therapy. We welcome questions and provide consultation to any staff members or their patients who have concerns regarding transfusion related issues. Please call us anytime with questions at the York Hospital Blood Bank, , or the Gettysburg Hospital Blood Bank, Herpes Simplex Type 1 and 2 Detection and Typing: Molecular Testing to Replace Tissue Culture Isolation and Identification Arthur E. Crist, Jr., Ph.D., Director, Clinical and Molecular Microbiology TEST NAME: Herpes Simplex Virus Detection and Typing TEST CODE: HSV PCR CPT-4 CODE: X 2 SPECIMEN: Specimens collected and transported using the BD Universal Viral Transport Kit (Contains one flocked swab and one red top 3 ml UVT tube) REFERENCE RANGE: Negative for Herpes simplex virus by DNA Amplification EFFECTIVE DATE: April 2, 2012 CONTACTS: Microbiology Lab ; Dr. Crist ; Dave Bankert LAB WEBSITE: Beginning April 2, 2012, the Microbiology Laboratory at York Hospital will be moving from a tissue culture based to a molecular based assay for detection and typing of herpes simplex virus. A study using the Laboratory Services Bulletin [March 2012, Vol. 42. No. 1] 3

4 molecular based method was conducted as follows in order to verify assay performance. The BD ProbeTec TM HSV Q x Amplified DNA Assay for detection and typing of herpes simplex virus (BD-HSV) performed on the BD Viper TM Instrument was compared to the shell vial tissue culture method used in our laboratory. The shell vial tissue culture consisted of inoculating each specimen to two vials; one containing mink lung cells (Mv1Lu) and the other containing MRC5 cells (Diagnostic Hybrids). Shell vial cultures were incubated at 37 o C for up to 5 days and inspected daily for cytopathic effect (CPE). All CPE positive samples were then typed using fluorescein-tagged monoclonal antibodies to HSV-1 or HSV-2 (Diagnostic Hybrids). There were 323 specimens evaluated in this study. BD-HSV produced 128 positive results compared to 117 by our shell vial culture. Of the 116 specimens that were positive by both methods, there were no discrepant typing results (55 HSV-1 and 61 HSV-2). When compared to shell vial culture, the BD-HSV had sensitivity, specificity, positive predictive value and negative predictive values of 99%, 94%, 91%, and 99%, respectively. There was one specimen that was positive by shell vial culture but negative by BD-HSV. All specimens were tested using the LightCycler PCR HSV 1/2 Detection Kit (R-HSV) (Roche Applied Science, Indianapolis, IN) to provide a comparative method to resolve discrepancies. Using a combined standard, a true positive was defined as a positive shell vial culture or a positive by both molecular tests. The recalculated sensitivity, specificity, positive predictive value and negative predictive values using the combined standard were all >99% for BD-HSV and 91%, 100%, 100%, and 95% for the shell vial tissue culture, respectively. The BD- HSV assay on the Viper Instrument proved to be more sensitive than, and as specific as, our shell vial tissue culture method. It also has the added benefit of faster turnaround time, less hands on time, and can be run simultaneously on the Viper Instrument with other assays, e.g. Chlamydia trachomatis and Neisseria gonorrhoeae Antibiograms Arthur E. Crist, Jr., Ph.D. Director, Clinical and Molecular Microbiology Robert M. Patti, PharmD, JD, Manager-Pharmacy Clinical Services Susan Shue, MT (ASCP), Division Manager, Laboratory-Gettysburg Hospital In this month s edition readers are provided with the cumulative 2011 antibiograms for isolates processed by the York Hospital Clinical and Microbiology Laboratory. This year includes inpatient, outpatient, nursing homes and for the first time an antibiogram for isolates recovered in the critical care units. Antibiograms provide an opportunity to ensure appropriate empiric antibiotic coverage when an organism is identified while awaiting susceptibilities. Local patterns of susceptibility and resistance afford comparison to national and regional data when clinicians are developing pathways for the treatment of infections based on established guidelines and recommendations. Antimicrobial susceptibility testing was performed according to the guidelines set forth by the Clinical Laboratory Standards Institute. Antibiotics utilized for development of the antibiograms reflect formulary antibiotics. The only exception is the use of cephalothin testing, which acts as a surrogate for cephalexin (Keflex) testing. Gram negative organisms such as E.coli may be susceptible to cefazolin (Ancef) but at the same time resistant to cephalothin. In this case while cefazolin (Ancef) would be effective therapy, cephalexin (Keflex) would not. Laboratory Services Bulletin [March 2012, Vol. 42. No. 1] 4

5 Organism E. Coli Enterobacter sp. Klebsiella sp. Pseudomonas aeruginosa Staphylococcus aureus (Inpt) (Inpatient Staphylococcus aureus (Outpt) Coagulase neg. Staphylococcus Enterococcus Species H. influenzae Streptococcus pneumoniae Gettysburg Hospital Laboratory Annual Percent Sensitive Antibiogram (2011) Drug Names Amakacin Amoxicillin/Clavulanate Ampicillin Ampicillin/ Sulbactam Azithromycin 50 Cefazolin Cefepime Cefotaxime Ceftriaxone Chloramphenicol Ciprofloxacin Clindamycin Daptomycin Ertapenem Erythromycin Gentamicin Imipenem Levofloxacin Linezolid Nitrourantoin Oxacillin Penicillin Pipercillin/Tazobactam Rifampin Tetracycline Tobramycin Trimeth/Sulfa Vancomycin NOTE: 1. Staphylococcus aureus : Cephalosporins are not effective in vivo for Methicillin Resistant Staph aureus(mrsa) infections. Reporting in vitro results for cephalosporins can be seriously misleading. Vancomycin is currently the drug of choice for MRSA. 2. Staphylococcus epidermidis: Usually regarded as a culture contaminant. However Coag neg Staphylococcus infections are increasing, especially in infections involving foreign devices, surgical wounds, and bacteremia in immunocompromised patients. Cross resistance between methicillin and cephalosporins are substantial. Therefore, all methicillin resistant isolates should be considered resistant to beta-lactam antibiotics. Treatment of choice is either vancomycin alone or in combination with an aminogylcoside or rifampin. 3. Enterococcus: In vitro sensitivity to cephalosporin, clindamycin, and aminoglycosides do not correlate to in vivo results. Therefore the are not reported. Uncomplicated enterococcal infections can be treated with a single therapy of penicillin, ampicillin, or vanocmycin. In serious deep seated infections, a combination therapy of high dose penicillins with an aminoglycoside is recommended. 4. NR= Not reported, insufficient number tested Prepared by: Peggy Waleski MT (ASCP) Laboratory Services Bulletin [March 2012, Vol. 42. No. 1] 5

6 Enterococcus faecalis Enterococcus faecium methicillin susceptible (b) methicillin resistant (b) Staphylococcus sp., coagulase negative Streptococcus pneumoniae Citrobacter freundii complex Enterobacter aerogenes (d) Enterobacter cloacae (d) Escherichia coli Klebsiella pneumoniae Morganella morgani Pseudomonas aeruginosa (c) Serratia marcescens (d) YORK HOSPITAL ANTIMICROBIAL SUSCEPTIBILITY TESTING * ( Jan. - Dec ) Inpatient Isolates Only Prepared by: Arthur E. Crist, Jr., Ph.D., Laboratory Robert Patti, Pharm.D., Pharmacy GRAM (+) COCCI Gram (-) RODS Drug Name Gentamicin (RRF) Tobramycin (RRF) Amikacin (RRF) Penicillin (RRF) Ampicillin (RRF) Amoxicillin/Clavulanate (RRF) Augmentin Ampicillin/Sulbactam (RRF) Unasyn PIP/Tazobactam (RRF) Zosyn Meropenem Ertapenem Imipenem Nafcillin (a) Rifampin (e) Vancomycin (RRF) Gentamicin Synergy Screen (f) Aztreonam Cefazolin (RRF) Cephalothin (g) Cefotetan (RRF) Cefotaxime Ceftriaxone Cefepime (RRF) Azithromycin 51 Clindamycin Doxycycline (h) TMP/SMX (RRF) Daptomycin Linezolid Synercid Nitrofurantoin (i) Ciprofloxacin (RRF) Levofloxacin (RRF) * Antimicrobial susceptibility testing performed according to the guidelines set forth in: (1) Clinical Laboratory Standards Insitute (CLSI). Performance standards for antimicrobial disk susceptibility tests; approved standard-ninth addition. M2-A10, Vol. 29, No. 1. January 2009; (2) CLSI. Methods for dilution antimicrobial susceptibility tests for bacteria that grow aerobically; approved standard-seventh edition. M7-A8, Vol. 29, No. 2, January 2009; and (3) CLSI. Performance Standards for Antimicrobial Susceptibility Testing; Twenty-First Informational Supplement. M100-S21, Vol. 31, No. 1, January 2011 KEY: (%) Susceptibility is number in block. Dark shaded block = antimicrobic is usually not used or tested for this organism. (a) Oxacillin tested. (b) Fifty five percent (55%) of Staph aureus cultures were methicillin susceptible; 45% were MRSA. (c) For serious pseudomonal infections two antipseudomonal antibiotics should be used. (d) For serious Serratia or Enterobacter infections, cefepime plus an aminoglycoside or a quinolone alone should be used. (e) Should not be used for monotherapy since resistance develops rapidly (f) Predicts synergy when using a beta-lactam and an aminoglycoside in combination therapy (g) Used to predict susceptibility to cephalexin (Keflex) and other first generation cephalosporins (h) Tetracycline tested, a larger percentage of isolates may be sensitive to doxycycline. (i) Urinary tract isolates only (RRF) Means dose should be adjusted for reduced renal function under 50ml/min. If adjustment is needed please contact the Pharmacy. Laboratory Services Bulletin [March 2012, Vol. 42. No. 1] 6

7 Enterococcus faecalis Enterococcus faecium methicillin susceptible (b) methicillin resistant (b) Staphylococcus sp., coagulase negative Streptococcus pneumoniae Citrobacter freundii complex Enterobacter aerogenes (d) Enterobacter cloacae (d) Escherichia coli Klebsiella pneumoniae Morganella morgani Pseudomonas aeruginosa (c) Serratia marcescens (d) YORK HOSPITAL ANTIMICROBIAL SUSCEPTIBILITY TESTING * ( Jan. - Dec ) Outpatient Isolates Only Prepared by: Arthur E. Crist, Jr., Ph.D., Laboratory Robert Patti, Pharm.D., Pharmacy GRAM (+) COCCI Gram (-) RODS Drug Name Gentamicin (RRF) Tobramycin (RRF) Amikacin (RRF) Penicillin (RRF) Ampicillin (RRF) Amoxicillin/Clavulanate (RRF) Augmentin Ampicillin/Sulbactam (RRF) Unasyn PIP/Tazobactam (RRF) Zosyn Meropenem Ertapenem Imipenem Nafcillin (a) Rifampin (e) Vancomycin (RRF) Gentamicin Synergy Screen (f) Aztreonam Cefazolin (RRF) Cephalothin (g) Cefotetan (RRF) Cefotaxime Ceftriaxone Cefepime (RRF) Azithromycin 50 Clindamycin Doxycycline (h) TMP/SMX (RRF) Daptomycin Linezolid Synercid Nitrofurantoin (i) Ciprofloxacin (RRF) Levofloxacin (RRF) * Antimicrobial susceptibility testing performed according to the guidelines set forth in: (1) Clinical Laboratory Standards Insitute (CLSI). Performance standards for antimicrobial disk susceptibility tests; approved standard-ninth addition. M2-A10, Vol. 29, No. 1. January 2009; (2) CLSI. Methods for dilution antimicrobial susceptibility tests for bacteria that grow aerobically; approved standard-seventh edition. M7-A8, Vol. 29, No. 2, January 2009; and (3) CLSI. Performance Standards for Antimicrobial Susceptibility Testing; Twenty-First Informational Supplement. M100-S21, Vol. 31, No. 1, January 2011 KEY: (%) Susceptibility is number in block. Dark shaded block = antimicrobic is usually not used or tested for this organism. (a) Oxacillin tested. (b) Fifty one percent (51%) of Staph aureus cultures were methicillin susceptible; 49% were MRSA. (c) For serious pseudomonal infections two antipseudomonal antibiotics should be used. (d) For serious Serratia or Enterobacter infections, cefepime plus an aminoglycoside or a quinolone alone should be used. (e) Should not be used for monotherapy since resistance develops rapidly (f) Predicts synergy when using a beta-lactam and an aminoglycoside in combination therapy (g) Used to predict susceptibility to cephalexin (Keflex) and other first generation cephalosporins (h) Tetracycline tested, a larger percentage of isolates may be sensitive to doxycycline. (i) Urinary tract isolates only (RRF) Means dose should be adjusted for reduced renal function under 50ml/min. If adjustment is needed please contact the Pharmacy. Laboratory Services Bulletin [March 2012, Vol. 42. No. 1] 7

8 Enterococcus faecalis Enterococcus faecium methicillin susceptible (b) methicillin resistant (b) Staphylococcus sp., coagulase negative Citrobacter freundii complex Enterobacter cloacae (d) Escherichia coli Klebsiella pneumoniae Morganella morgani Pseudomonas aeruginosa (c) YORK HOSPITAL ANTIMICROBIAL SUSCEPTIBILITY TESTING * ( Jan. - Dec ) Nursing Home Isolates Only Prepared by: Arthur E. Crist, Jr., Ph.D., Laboratory Robert Patti, Pharm.D., Pharmacy GRAM (+) COCCI Gram (-) Rods Drug Name Gentamicin (RRF) Tobramycin (RRF) Amikacin (RRF) Penicillin (RRF) Ampicillin (RRF) Amoxicillin/Clavulanate (RRF) Augmentin Ampicillin/Sulbactam (RRF) Unasyn PIP/Tazobactam (RRF) Zosyn Meropenem Ertapenem Imipenem Nafcillin (a) Rifampin (e) Vancomycin (RRF) Gentamicin Synergy Screen (f) Aztreonam Cefazolin (RRF) Cephalothin (g) Cefotetan (RRF) Cefotaxime Ceftriaxone Cefepime (RRF) Clindamycin Doxycycline (h) TMP/SMX (RRF) Daptomycin Linezolid Synercid Nitrofurantoin (i) Ciprofloxacin (RRF) Levofloxacin (RRF) * Antimicrobial susceptibility testing performed according to the guidelines set forth in: (1) Clinical Laboratory Standards Insitute (CLSI). Performance standards for antimicrobial disk susceptibility tests; approved standard-ninth addition. M2-A10, Vol. 29, No. 1. January 2009; (2) CLSI. Methods for dilution antimicrobial susceptibility tests for bacteria that grow aerobically; approved standard-seventh edition. M7-A8, Vol. 29, No. 2, January 2009; and (3) CLSI. Performance Standards for Antimicrobial Susceptibility Testing; Twenty-First Informational Supplement. M100-S21, Vol. 31, No. 1, January 2011 KEY: (%) Susceptibility is number in block. Dark shaded block = antimicrobic is usually not used or tested for this organism. (a) Oxacillin tested. (b) Thirty one percent (31%) of Staph aureus cultures were methicillin sensitive; 69% were MRSA. (c) For serious pseudomonal infections two antipseudomonal antibiotics should be used. (d) For serious Serratia or Enterobacter infections, cefepime plus an aminoglycoside or a quinolone alone should be used. (e) Should not be used for monotherapy since resistance develops rapidly (f) Predicts synergy when using a beta-lactam and an aminoglycoside in combination therapy (g) Used to predict susceptibility to cephalexin (Keflex) and other first generation cephalosporins (h) Tetracycline tested, a larger percentage of isolates may be sensitive to doxycycline. (i) Urinary tract isolates only (RRF) Means dose should be adjusted for reduced renal function under 50ml/min. If adjustment is needed please contact the Pharmacy. Laboratory Services Bulletin [March 2012, Vol. 42. No. 1] 8

9 Enterococcus faecalis Enterococcus faecium methicillin susceptible (b) methicillin resistant (b) Staphylococcus sp., coagulase negative Citrobacter freundii complex Enterobacter cloacae (d) Escherichia coli Klebsiella pneumoniae Pseudomonas aeruginosa (c) Serratia marcescens (d) Prepared by: Arthur E. Crist, Jr., Ph.D., Laboratory Robert Patti, Pharm.D., Pharmacy YORK HOSPITAL ANTIMICROBIAL SUSCEPTIBILITY TESTING * ( Jan. - Dec ) Critical Care Isolates Only GRAM (+) COCCI Gram (-) Rods Drug Name Gentamicin (RRF) Tobramycin (RRF) Amikacin (RRF) Penicillin (RRF) Ampicillin (RRF) Amoxicillin/Clavulanate (RRF) Augmentin Ampicillin/Sulbactam (RRF) Unasyn PIP/Tazobactam (RRF) Zosyn Meropenem Ertapenem Imipenem Nafcillin (a) Rifampin (e) Vancomycin (RRF) Gentamicin Synergy Screen (f) Aztreonam Cefazolin (RRF) Cephalothin (g) Cefotetan (RRF) Cefotaxime Ceftriaxone Cefepime (RRF) Clindamycin Doxycycline (h) TMP/SMX (RRF) Daptomycin Linezolid Synercid Nitrofurantoin (i) Ciprofloxacin (RRF) Levofloxacin (RRF) * Antimicrobial susceptibility testing performed according to the guidelines set forth in: (1) Clinical Laboratory Standards Insitute (CLSI). Performance standards for antimicrobial disk susceptibility tests; approved standard-ninth addition. M2-A10, Vol. 29, No. 1. January 2009; (2) CLSI. Methods for dilution antimicrobial susceptibility tests for bacteria that grow aerobically; approved standard-seventh edition. M7-A8, Vol. 29, No. 2, January 2009; and (3) CLSI. Performance Standards for Antimicrobial Susceptibility Testing; Twenty-First Informational Supplement. M100-S21, Vol. 31, No. 1, January 2011 KEY: (%) Susceptibility is number in block. Dark shaded block = antimicrobic is usually not used or tested for this organism. (a) Oxacillin tested. (b) Fifty six percent (56%) of Staph aureus cultures were methicillin susceptible; 44% were MRSA. (c) For serious pseudomonal infections two antipseudomonal antibiotics should be used. (d) For serious Serratia or Enterobacter infections, cefepime plus an aminoglycoside or a quinolone alone should be used. (e) Should not be used for monotherapy since resistance develops rapidly (f) Predicts synergy when using a beta-lactam and an aminoglycoside in combination therapy (g) Used to predict susceptibility to cephalexin (Keflex) and other first generation cephalosporins (h) Tetracycline tested, a larger percentage of isolates may be sensitive to doxycycline. (i) Urinary tract isolates only (RRF) Means dose should be adjusted for reduced renal function under 50ml/min. If adjustment is needed please contact the Pharmacy. Laboratory Services Bulletin [March 2012, Vol. 42. No. 1] 9