Selected Clinical and Laboratory Standards Institute M100a Breakpoints Not Recognized by the Center for Drug Evaluation and Research
| Organism . | Antimicrobial . | Resistance Rates in US by 2023 CLSI Breakpoints [Ref] . | Professional Societies That Recommend as Treatment Option [Ref] . |
|---|---|---|---|
| Acinetobacter spp | Cefepime | 37% [7, 8] | UpToDate: Considered first-line therapy by expert opinion for susceptible isolates. Resistance contributes to the case definition of MDR and XDR isolates [9] |
| Polymyxin B/Colistin | 8%–22% [7, 8] | IDSA: In combination with at least 1 other agent for treatment of carbapenem-resistant Acinetobacter baumannii if MIC ≤2 µg/mL [10] | |
| Streptococcus pyogenes | Azithromycin | 35.1% [11] | IDSA: Treatment of acute group A Streptococcus pharyngitis in patients allergic to penicillin [12] |
| Streptococcus agalactiae | Azithromycin | 60.0% [11] | ACOG: Alternative treatment for preterm prelabor rupture of membranes in pregnant women with documented β-lactam allergy [13] |
| Burkholderia cepacia complex | All antimicrobials | Ceftazidime: 5.0% Meropenem: 5.9% Levofloxacin: 18.8% Minocycline: 5.0% SXT: 6.9% [8] | None but routinely performed for the care of patients with cystic fibrosis |
| Salmonella | Azithromycin | 5.9% (typhoidal); 1.7% (nontyphoidal) [14] | IDSA: Treatment of bloody diarrhea based on local susceptibility patterns [15] American Academy of Family Physicians: First-line therapy for infectious diarrhea, if treatment is indicated [16] |
| Shigella | Azithromycin | 28.3% [14] | IDSA: Treatment of bloody diarrhea based on local susceptibility patterns [15] |
| Enterobacterales, including Escherichia coli and Klebsiella pneumoniae | Cefazolin as a surrogate for oral cephalosporins for treatment of uncomplicated UTI | No data, but anticipated to be ≥10%, based on ESBL rates | UpToDate: Second-line agent for treatment of uncomplicated cystitis |
| Enterococcus faecium | Daptomycin | 0.4% [17] | American Heart Association: Endocarditis caused by enterococci resistant to penicillin, aminoglycosides, and vancomycin [18] European Society of Cardiology: Endocarditis (in combination with ampicillin) for vancomycin-resistant enterococci [19] |
| Neisseria gonorrhoeae | Azithromycin | 5.8% [20] | CDC: In combination with gentamicin if ceftriaxone is not available [21] |
| Neisseria meningitidis | Ciprofloxacin, levofloxacin | Low, but of concern [22] | CDC: Chemoprophylaxis for close contacts of infected individuals [23, 24] |
| Non-Enterobacterales (includes Pseudomonas spp excluding P. aeruginosa, such as Pseudomonas putida) | All antimicrobials | No data—varies substantially by genus | None, although antibiotic treatment is indicated if causing an infection |
| Staphylococcus spp | Doxycycline SXT | <5% <5% | IDSA: Empiric therapy of mild diabetic foot infections if a β-lactam allergy is present or if high risk for MRSA and moderate to severe infections if MRSA risk factors present [25]; SSTI with surrounding cellulitis [26]; osteomyelitis (in combination with rifampin) [27] |
| Rifampin | <5% | IDSA (in combination with another agent): MRSA prosthetic valve endocarditis; MRSA osteomyelitis; MRSA device-related osteoarticular infections; MRSA meningitis; MRSA brain abscess, subdural empyema, spinal epidural abscess; MRSA septic thrombosis of cavernous or dural venous sinus; MRSA bacteremia vancomycin treatment failures [27] | |
| Stenotrophomonas maltophilia | Cefiderocol | 0% [28] | IDSA: Use any of these antibiotics, in combination with 1 other agent with activity, for infections caused by S. maltophilia [10] |
| Levofloxacin | 10.1% [28] | ||
| Minocycline | 0.0% [28] | ||
| SXT | 2.1% [28] |
| Organism . | Antimicrobial . | Resistance Rates in US by 2023 CLSI Breakpoints [Ref] . | Professional Societies That Recommend as Treatment Option [Ref] . |
|---|---|---|---|
| Acinetobacter spp | Cefepime | 37% [7, 8] | UpToDate: Considered first-line therapy by expert opinion for susceptible isolates. Resistance contributes to the case definition of MDR and XDR isolates [9] |
| Polymyxin B/Colistin | 8%–22% [7, 8] | IDSA: In combination with at least 1 other agent for treatment of carbapenem-resistant Acinetobacter baumannii if MIC ≤2 µg/mL [10] | |
| Streptococcus pyogenes | Azithromycin | 35.1% [11] | IDSA: Treatment of acute group A Streptococcus pharyngitis in patients allergic to penicillin [12] |
| Streptococcus agalactiae | Azithromycin | 60.0% [11] | ACOG: Alternative treatment for preterm prelabor rupture of membranes in pregnant women with documented β-lactam allergy [13] |
| Burkholderia cepacia complex | All antimicrobials | Ceftazidime: 5.0% Meropenem: 5.9% Levofloxacin: 18.8% Minocycline: 5.0% SXT: 6.9% [8] | None but routinely performed for the care of patients with cystic fibrosis |
| Salmonella | Azithromycin | 5.9% (typhoidal); 1.7% (nontyphoidal) [14] | IDSA: Treatment of bloody diarrhea based on local susceptibility patterns [15] American Academy of Family Physicians: First-line therapy for infectious diarrhea, if treatment is indicated [16] |
| Shigella | Azithromycin | 28.3% [14] | IDSA: Treatment of bloody diarrhea based on local susceptibility patterns [15] |
| Enterobacterales, including Escherichia coli and Klebsiella pneumoniae | Cefazolin as a surrogate for oral cephalosporins for treatment of uncomplicated UTI | No data, but anticipated to be ≥10%, based on ESBL rates | UpToDate: Second-line agent for treatment of uncomplicated cystitis |
| Enterococcus faecium | Daptomycin | 0.4% [17] | American Heart Association: Endocarditis caused by enterococci resistant to penicillin, aminoglycosides, and vancomycin [18] European Society of Cardiology: Endocarditis (in combination with ampicillin) for vancomycin-resistant enterococci [19] |
| Neisseria gonorrhoeae | Azithromycin | 5.8% [20] | CDC: In combination with gentamicin if ceftriaxone is not available [21] |
| Neisseria meningitidis | Ciprofloxacin, levofloxacin | Low, but of concern [22] | CDC: Chemoprophylaxis for close contacts of infected individuals [23, 24] |
| Non-Enterobacterales (includes Pseudomonas spp excluding P. aeruginosa, such as Pseudomonas putida) | All antimicrobials | No data—varies substantially by genus | None, although antibiotic treatment is indicated if causing an infection |
| Staphylococcus spp | Doxycycline SXT | <5% <5% | IDSA: Empiric therapy of mild diabetic foot infections if a β-lactam allergy is present or if high risk for MRSA and moderate to severe infections if MRSA risk factors present [25]; SSTI with surrounding cellulitis [26]; osteomyelitis (in combination with rifampin) [27] |
| Rifampin | <5% | IDSA (in combination with another agent): MRSA prosthetic valve endocarditis; MRSA osteomyelitis; MRSA device-related osteoarticular infections; MRSA meningitis; MRSA brain abscess, subdural empyema, spinal epidural abscess; MRSA septic thrombosis of cavernous or dural venous sinus; MRSA bacteremia vancomycin treatment failures [27] | |
| Stenotrophomonas maltophilia | Cefiderocol | 0% [28] | IDSA: Use any of these antibiotics, in combination with 1 other agent with activity, for infections caused by S. maltophilia [10] |
| Levofloxacin | 10.1% [28] | ||
| Minocycline | 0.0% [28] | ||
| SXT | 2.1% [28] |
Abbreviations: ACOG, American College of Obstetricians and Gynecologists; CDC, Centers for Disease Control and Prevention; CLSI, Clinical and Laboratory Standards Institute; ESBL, extended-spectrum β-lactamase; IDSA, Infectious Diseases Society of America; MDR, multidrug-resistant; MIC, minimum inhibitory concentration; MRSA, methicillin-resistant Staphylococcus aureus; SSTI, skin and soft tissue infection; SXT, trimethoprim-sulfamethoxazole; UTI, urinary tract infection; XDR, extensively drug-resistant.
aAdditional breakpoints published in M45 are not recognized by the Center for Drug Evaluation and Research.
Selected Clinical and Laboratory Standards Institute M100a Breakpoints Not Recognized by the Center for Drug Evaluation and Research
| Organism . | Antimicrobial . | Resistance Rates in US by 2023 CLSI Breakpoints [Ref] . | Professional Societies That Recommend as Treatment Option [Ref] . |
|---|---|---|---|
| Acinetobacter spp | Cefepime | 37% [7, 8] | UpToDate: Considered first-line therapy by expert opinion for susceptible isolates. Resistance contributes to the case definition of MDR and XDR isolates [9] |
| Polymyxin B/Colistin | 8%–22% [7, 8] | IDSA: In combination with at least 1 other agent for treatment of carbapenem-resistant Acinetobacter baumannii if MIC ≤2 µg/mL [10] | |
| Streptococcus pyogenes | Azithromycin | 35.1% [11] | IDSA: Treatment of acute group A Streptococcus pharyngitis in patients allergic to penicillin [12] |
| Streptococcus agalactiae | Azithromycin | 60.0% [11] | ACOG: Alternative treatment for preterm prelabor rupture of membranes in pregnant women with documented β-lactam allergy [13] |
| Burkholderia cepacia complex | All antimicrobials | Ceftazidime: 5.0% Meropenem: 5.9% Levofloxacin: 18.8% Minocycline: 5.0% SXT: 6.9% [8] | None but routinely performed for the care of patients with cystic fibrosis |
| Salmonella | Azithromycin | 5.9% (typhoidal); 1.7% (nontyphoidal) [14] | IDSA: Treatment of bloody diarrhea based on local susceptibility patterns [15] American Academy of Family Physicians: First-line therapy for infectious diarrhea, if treatment is indicated [16] |
| Shigella | Azithromycin | 28.3% [14] | IDSA: Treatment of bloody diarrhea based on local susceptibility patterns [15] |
| Enterobacterales, including Escherichia coli and Klebsiella pneumoniae | Cefazolin as a surrogate for oral cephalosporins for treatment of uncomplicated UTI | No data, but anticipated to be ≥10%, based on ESBL rates | UpToDate: Second-line agent for treatment of uncomplicated cystitis |
| Enterococcus faecium | Daptomycin | 0.4% [17] | American Heart Association: Endocarditis caused by enterococci resistant to penicillin, aminoglycosides, and vancomycin [18] European Society of Cardiology: Endocarditis (in combination with ampicillin) for vancomycin-resistant enterococci [19] |
| Neisseria gonorrhoeae | Azithromycin | 5.8% [20] | CDC: In combination with gentamicin if ceftriaxone is not available [21] |
| Neisseria meningitidis | Ciprofloxacin, levofloxacin | Low, but of concern [22] | CDC: Chemoprophylaxis for close contacts of infected individuals [23, 24] |
| Non-Enterobacterales (includes Pseudomonas spp excluding P. aeruginosa, such as Pseudomonas putida) | All antimicrobials | No data—varies substantially by genus | None, although antibiotic treatment is indicated if causing an infection |
| Staphylococcus spp | Doxycycline SXT | <5% <5% | IDSA: Empiric therapy of mild diabetic foot infections if a β-lactam allergy is present or if high risk for MRSA and moderate to severe infections if MRSA risk factors present [25]; SSTI with surrounding cellulitis [26]; osteomyelitis (in combination with rifampin) [27] |
| Rifampin | <5% | IDSA (in combination with another agent): MRSA prosthetic valve endocarditis; MRSA osteomyelitis; MRSA device-related osteoarticular infections; MRSA meningitis; MRSA brain abscess, subdural empyema, spinal epidural abscess; MRSA septic thrombosis of cavernous or dural venous sinus; MRSA bacteremia vancomycin treatment failures [27] | |
| Stenotrophomonas maltophilia | Cefiderocol | 0% [28] | IDSA: Use any of these antibiotics, in combination with 1 other agent with activity, for infections caused by S. maltophilia [10] |
| Levofloxacin | 10.1% [28] | ||
| Minocycline | 0.0% [28] | ||
| SXT | 2.1% [28] |
| Organism . | Antimicrobial . | Resistance Rates in US by 2023 CLSI Breakpoints [Ref] . | Professional Societies That Recommend as Treatment Option [Ref] . |
|---|---|---|---|
| Acinetobacter spp | Cefepime | 37% [7, 8] | UpToDate: Considered first-line therapy by expert opinion for susceptible isolates. Resistance contributes to the case definition of MDR and XDR isolates [9] |
| Polymyxin B/Colistin | 8%–22% [7, 8] | IDSA: In combination with at least 1 other agent for treatment of carbapenem-resistant Acinetobacter baumannii if MIC ≤2 µg/mL [10] | |
| Streptococcus pyogenes | Azithromycin | 35.1% [11] | IDSA: Treatment of acute group A Streptococcus pharyngitis in patients allergic to penicillin [12] |
| Streptococcus agalactiae | Azithromycin | 60.0% [11] | ACOG: Alternative treatment for preterm prelabor rupture of membranes in pregnant women with documented β-lactam allergy [13] |
| Burkholderia cepacia complex | All antimicrobials | Ceftazidime: 5.0% Meropenem: 5.9% Levofloxacin: 18.8% Minocycline: 5.0% SXT: 6.9% [8] | None but routinely performed for the care of patients with cystic fibrosis |
| Salmonella | Azithromycin | 5.9% (typhoidal); 1.7% (nontyphoidal) [14] | IDSA: Treatment of bloody diarrhea based on local susceptibility patterns [15] American Academy of Family Physicians: First-line therapy for infectious diarrhea, if treatment is indicated [16] |
| Shigella | Azithromycin | 28.3% [14] | IDSA: Treatment of bloody diarrhea based on local susceptibility patterns [15] |
| Enterobacterales, including Escherichia coli and Klebsiella pneumoniae | Cefazolin as a surrogate for oral cephalosporins for treatment of uncomplicated UTI | No data, but anticipated to be ≥10%, based on ESBL rates | UpToDate: Second-line agent for treatment of uncomplicated cystitis |
| Enterococcus faecium | Daptomycin | 0.4% [17] | American Heart Association: Endocarditis caused by enterococci resistant to penicillin, aminoglycosides, and vancomycin [18] European Society of Cardiology: Endocarditis (in combination with ampicillin) for vancomycin-resistant enterococci [19] |
| Neisseria gonorrhoeae | Azithromycin | 5.8% [20] | CDC: In combination with gentamicin if ceftriaxone is not available [21] |
| Neisseria meningitidis | Ciprofloxacin, levofloxacin | Low, but of concern [22] | CDC: Chemoprophylaxis for close contacts of infected individuals [23, 24] |
| Non-Enterobacterales (includes Pseudomonas spp excluding P. aeruginosa, such as Pseudomonas putida) | All antimicrobials | No data—varies substantially by genus | None, although antibiotic treatment is indicated if causing an infection |
| Staphylococcus spp | Doxycycline SXT | <5% <5% | IDSA: Empiric therapy of mild diabetic foot infections if a β-lactam allergy is present or if high risk for MRSA and moderate to severe infections if MRSA risk factors present [25]; SSTI with surrounding cellulitis [26]; osteomyelitis (in combination with rifampin) [27] |
| Rifampin | <5% | IDSA (in combination with another agent): MRSA prosthetic valve endocarditis; MRSA osteomyelitis; MRSA device-related osteoarticular infections; MRSA meningitis; MRSA brain abscess, subdural empyema, spinal epidural abscess; MRSA septic thrombosis of cavernous or dural venous sinus; MRSA bacteremia vancomycin treatment failures [27] | |
| Stenotrophomonas maltophilia | Cefiderocol | 0% [28] | IDSA: Use any of these antibiotics, in combination with 1 other agent with activity, for infections caused by S. maltophilia [10] |
| Levofloxacin | 10.1% [28] | ||
| Minocycline | 0.0% [28] | ||
| SXT | 2.1% [28] |
Abbreviations: ACOG, American College of Obstetricians and Gynecologists; CDC, Centers for Disease Control and Prevention; CLSI, Clinical and Laboratory Standards Institute; ESBL, extended-spectrum β-lactamase; IDSA, Infectious Diseases Society of America; MDR, multidrug-resistant; MIC, minimum inhibitory concentration; MRSA, methicillin-resistant Staphylococcus aureus; SSTI, skin and soft tissue infection; SXT, trimethoprim-sulfamethoxazole; UTI, urinary tract infection; XDR, extensively drug-resistant.
aAdditional breakpoints published in M45 are not recognized by the Center for Drug Evaluation and Research.
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