Emerging Antimicrobial Resistance in Texas The new ESBLs

Most Important Emerging Resistance MRSA in the community MRSA in the community Resistance to alternative drugs for MRSA, including vancomycin Resistance to alternative drugs for MRSA, including vancomycin Re-emergence of DRSP Re-emergence of DRSP ESBL in various gram-negative species ESBL in various gram-negative species Carbapenemases in various GNs Carbapenemases in various GNs Multi-drug resistance in Pseudomonas, enterics, Acinetobacter, S. maltophilia Multi-drug resistance in Pseudomonas, enterics, Acinetobacter, S. maltophilia

To Review ESBL background……

Extended Spectrum Beta- Lactamases Most ESBL - mutations of TEM or SHV plasmid-mediated enzymes normally found in E. coli and Klebsiella Most ESBL - mutations of TEM or SHV plasmid-mediated enzymes normally found in E. coli and Klebsiella Now TEM-1 to 161, SHV-1 to 105 (as of ) - Source: Now TEM-1 to 161, SHV-1 to 105 (as of ) - Source: Differences in substrate specificity - especially ceftaz vs. cefotax Differences in substrate specificity - especially ceftaz vs. cefotax Hydrolyze 3rd and 4th gen cephs and aztreonam at high bacterial inoculum Hydrolyze 3rd and 4th gen cephs and aztreonam at high bacterial inoculum

Enzyme Ceftaz Amino Acid Position MIC MIC TEM GluArgGlu TEM-10 > 256GluSerLys TEM-12 16GluSerGlu TEM LysSerGlu from: Jacoby, IDCNA 11:875, 1997 Molecular Basis of ESBLs

Different Substrate Affinities of ESBL Enzyme MICs Ceftaz Cefotax Aztreo Ceftaz Cefotax Aztreo TEM TEM-10> TEM TEM from: Jacoby, IDCNA 11:875, 1997 from: Jacoby, IDCNA 11:875, 1997

Inoculum Effect with ESBLs - MICs with SHV-3 producing C. freundii Inoculum Inoculum Cefotaxime2256 Ceftazidime1 32 Cefepime0.5>128 Meropenem Thomson, AAC45:3548, 2001

Clinical Significance of ESBLs Global bacteremia study in ‘96 and ‘97 Global bacteremia study in ‘96 and ‘ K. pneumoniae -18.7% (85) produced ESBLs -9 treated with a cephalosporin that was CLSI Susceptible or Intermediate -3 died, 5 required Rx change Overall, 32 pts. Rx with a ceph (S or I) Overall, 32 pts. Rx with a ceph (S or I) -4/4 I’s failed; 15/28 S’s failed -4/5 treated with cefepime failed D. Paterson, JCM 2001

Two Step Process of Detection and Confirmation of ESBLs Test “indicator” drugs with special “screening” breakpoints Test “indicator” drugs with special “screening” breakpoints -cefpodoxime or look for elevated MICs of ceph 3s Must confirm with clavulanate combos of cefotaxime and ceftazidime by MIC or disk Must confirm with clavulanate combos of cefotaxime and ceftazidime by MIC or disk Report as ESBL if either clavulanate combo is positive Report as ESBL if either clavulanate combo is positive

Laboratory Reporting of ESBL-Producing Isolates “Expertize” results to resistant for all penicillins, aztreonam, and “true cephalosporins” irrespective of individual test results and/or “Expertize” results to resistant for all penicillins, aztreonam, and “true cephalosporins” irrespective of individual test results and/or Provide a warning comment that ESBL-producers should be considered clinically resistant to all penicillins, cephalosporins, and aztreonam Provide a warning comment that ESBL-producers should be considered clinically resistant to all penicillins, cephalosporins, and aztreonam

Gram-Negative Species Known to Harbor ESBL Klebsiella pneumoniae Klebsiella pneumoniae Klebsiella oxytoca Klebsiella oxytoca E. coli E. coli Proteus mirabilis Proteus mirabilis Salmonella spp. Salmonella spp. Also in Citrobacter, Enterobacter, Serratia, Morganella, P. aeruginosa, Acinetobacter Also in Citrobacter, Enterobacter, Serratia, Morganella, P. aeruginosa, Acinetobacter

AmpC Beta-Lactamase ampC gene is present in all Enterobacter, Citrobacter freundii, Morganella morganii, P. aeruginosa ampC gene is present in all Enterobacter, Citrobacter freundii, Morganella morganii, P. aeruginosa Selection of resistant mutants with “up- regulated” production of ampC during therapy Selection of resistant mutants with “up- regulated” production of ampC during therapy -Resistance to all cephs except cefepime ampC can be plasmid-mediated in some E. coli and K. pneumoniae ampC can be plasmid-mediated in some E. coli and K. pneumoniae –Jacoby and Munoz-Price, NEJM 352:380, 2005

ESBL vs. AmpC ESBL Spectrum “extended” from parent enzyme Spectrum “extended” from parent enzyme Susceptible to cefotetan Susceptible to cefotetan Inhibited by clavulanate Inhibited by clavulanate Can hydrolyze cefepime at high inoculum Can hydrolyze cefepime at high inoculum Carbapenem susceptible Carbapenem susceptibleampC Spectrum not “extended,” although may be basal or hyperproducing level Spectrum not “extended,” although may be basal or hyperproducing level Resistant to cefotetan Resistant to cefotetan Not inhibited by clav Not inhibited by clav Hydrolyzes cefepime poorly Hydrolyzes cefepime poorly Carbapenem suscept Carbapenem suscept

ESBL That Are Not Derived From TEM or SHV CTX-M-1 thru 69 - hydrolyze cefotaxime better than ceftazidime CTX-M-1 thru 69 - hydrolyze cefotaxime better than ceftazidime -Derived from Kluyvera ascorbata -Most common ESBL in Latin America, Japan, Eastern Europe, and U.S.? OXA-1 thru 119 (~11 ESBL) OXA-1 thru 119 (~11 ESBL) -Mostly in Eastern Europe -Usually in P. aeruginosa or Acinetobacter

E. coli with “Cefotaximase”

P. mirabilis with CTX-M15

E. cloacae with CTX-M15: Use of cefepime + clavulanate

Increasing Numbers of ESBLs Lewis, et al. AAC 51:4015, 2007

“First Report of the Emergence of CTX-M Type ESBLs as the Predominant ESBL Isolated in a U.S. Healthcare System” Retrieved all frozen ESBL isolates from mid 2006 Retrieved all frozen ESBL isolates from mid Standard CLSI ESBL screening and confirmatory tests used throughout period -Screening by cefpodoxime disk and Vitek 2 PCR and sequencing for TEM, SHV, CTX-M (and OXA in some) PCR and sequencing for TEM, SHV, CTX-M (and OXA in some) Lewis, et al, AAC, November, 2007

Emergence of CTX-M ESBLs in San Antonio Have emerged as predominant ESBL over last 3 years Have emerged as predominant ESBL over last 3 years -%CTX-M in : 0-25% -%CTX-M in : 60-89% CTX-M in E. coli, K. pneumoniae, K. oxytoca, P. mirabilis, Enterobacter spp., M. morganii CTX-M in E. coli, K. pneumoniae, K. oxytoca, P. mirabilis, Enterobacter spp., M. morganii Now predominantly CTX-M15 in E. coli, often outpatient urines - 8% with 2nd ESBL Now predominantly CTX-M15 in E. coli, often outpatient urines - 8% with 2nd ESBL 86% fluoroquinolone resistant; 66% to SXT 86% fluoroquinolone resistant; 66% to SXT Lewis, et al, AAC 2007Lewis, et al, AAC 2007

Evolution of CTX-M ESBLs From Lewis, et al, AAC 51:4015, 2007

ESBL Producers in % (48) of ESBL in E. coli; 15% (11) in K. pneumoniae, 9.3% (7) K. oxytoca, 6.7% (5) Enterobacter, 2 Serratia, 1 P. mirabilis, 1C. koseri 64% (48) of ESBL in E. coli; 15% (11) in K. pneumoniae, 9.3% (7) K. oxytoca, 6.7% (5) Enterobacter, 2 Serratia, 1 P. mirabilis, 1C. koseri 53% from urine; 22% from blood or BF 53% from urine; 22% from blood or BF What are risk factors for OP E coli CTX-M UTI? What are risk factors for OP E coli CTX-M UTI? When is a urine culture needed? When is a urine culture needed? What agents are available for therapy of OP E. coli ESBL? What agents are available for therapy of OP E. coli ESBL?

ESBL Producers in % (48) of ESBL in E. coli; 15% (11) in K. pneumoniae, 9.3% (7) K. oxytoca, 6.7% (5) Enterobacter, 2 Serratia, 1 P. mirabilis, 1C. koseri 64% (48) of ESBL in E. coli; 15% (11) in K. pneumoniae, 9.3% (7) K. oxytoca, 6.7% (5) Enterobacter, 2 Serratia, 1 P. mirabilis, 1C. koseri 53% from urine; 22% from blood or BF 53% from urine; 22% from blood or BF What are risk factors for OP E coli CTX-M UTI? What are risk factors for OP E coli CTX-M UTI? When is a urine culture needed? When is a urine culture needed? What agents are available for therapy of OP E. coli ESBL? What agents are available for therapy of OP E. coli ESBL?

Cefotaxime and Ceftazidime Zones with Different Species Producing CTX-M ESBLs

The Newest Mechanisms of Concern - Carbapenemases The alphabet soup of rapidly emerging carbapenemases The alphabet soup of rapidly emerging carbapenemases -KPCs 1-4 -IMP VIM PER, SME, VEB -Some OXA enzymes Source:

KPC Carbapenemases Plasmid-mediated - KPCs 1-4 Plasmid-mediated - KPCs 1-4 -Klebsiella pneumoniae carbapenemase -Can hydrolyze all beta-lactams, including carbapenems -Often also resistant to FQs, SXT, aminoglycosides - Suscept to colistin, tigecycline -Have rapidly spread in the Eastern U.S. -Difficult to detect by commercial or ref. methods -Are they in Texas??

How Do Labs Perform in Detection of KPCs? CAP sample DA-05, 2007 illustrated problems of detection CAP sample DA-05, 2007 illustrated problems of detection -Partial or inconsistent clavulanate effect - like ESBL -Some commercial systems (and disks) had a high false susceptible rate with imipenem -Meropenem also problematic -Best detection by testing ertapenem -Ertapenem > meropenem > imipenem

Detection of KPCs Look for resistance to all penicillins and cephalosporins Look for resistance to all penicillins and cephalosporins Look for carbapenem MICs > 1 Look for carbapenem MICs > 1 Perform “modified Hodge test” Perform “modified Hodge test” PCR using primers for all KPC, and sequence product PCR using primers for all KPC, and sequence product

Modified Hodge Test

Other Carbapenemases - Metallo-Beta-Lactamases Mostly found in P. aeruginosa Mostly found in P. aeruginosa -IMP, VIM, SIM, GIM, and SPM -Europe, Asia, S. America, N. America (IMP, VIM) -Plasmid, chromosomal, or integrons P. aeruginosa with VIM-2 in CAP DA-01, 2007 P. aeruginosa with VIM-2 in CAP DA-01, Resistant to all carbapenems, cephs, pens -Suscept. to aztreonam, pip-tazo -Colistin suceptible

Newer Beta-Lactamases are emerging in Texas Labs must look for them Labs must look for them Physicians must be aware of their existence Physicians must be aware of their existence