Extended-spectrum β-lactamases - Revision history

Aidan: /* Management */

2024-11-14T02:22:13Z

Management

← Older revision		Revision as of 02:22, 14 November 2024
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	== Management ==		== Management ==

			* Carbapenem, with [[meropenem]] or [[imipenem]] preferentially, though [[ertapenem]] can be considered if no septic shock[[Pichia kudriavzevii]]
			* In some patients, can consider [[piperacillin-tazobactam]], [[amoxicillin-clavulanic acid]], or [[fluoroquinolones]]
			* For non-severe [[UTI]] without septic shock, can consider [[co-trimoxazole]], [[aminoglycosides]], or [[fosfomycin]] (IV)
	* See also [[Carbapenem-resistant organisms]]		* See also [[Carbapenem-resistant organisms]]

Aidan at 16:09, 2 April 2022

2022-04-02T16:09:05Z

← Older revision		Revision as of 16:09, 2 April 2022
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	**An increase in the zone of ≥4 mm is positive for AmpC (Class C ESBL) phenotype		**An increase in the zone of ≥4 mm is positive for AmpC (Class C ESBL) phenotype
	*'''Class D''', difficult to identify with phenotypic testing		*'''Class D''', difficult to identify with phenotypic testing

			== Management ==

			* See also [[Carbapenem-resistant organisms]]

Aidan at 22:19, 17 September 2020

2020-09-17T22:19:25Z

← Older revision		Revision as of 22:19, 17 September 2020
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	== Background ==		==Background==

	* Extended-spectrum β-lactamases (ESBLs) are generally defined as [[β-lactamases]] that hydrolyze [[penicillins]], first-, second-, and third-generation [[cephalosporins]], and [[aztreonam]], but not [[cephamycins]] or [[carbapenems]]		*Extended-spectrum β-lactamases (ESBLs) are generally defined as [[β-lactamases]] that hydrolyze [[penicillins]], first-, second-, and third-generation [[cephalosporins]], and [[aztreonam]], but not [[cephamycins]] or [[carbapenems]]
	* This definition excludes AmpC (which hydrolyze [[cephamycins]]) and carbapenemases (which hydrolyze [[carbapenems]])		*This definition excludes AmpC (which hydrolyze [[cephamycins]]) and carbapenemases (which hydrolyze [[carbapenems]])
	* Includes primarily Ambler Class A β-lactamases		*Includes primarily Ambler Class A β-lactamases

	=== Identification ===		===Identification===

	* ESBLs are screened for by identifying organisms with increased MICs to one or more third-generation [[Cephalosporins\|cephalosporin]] or [[Monobactams\|monobactam]]		*ESBLs are screened for by identifying organisms with increased MICs to one or more third-generation [[Cephalosporins\|cephalosporin]] or [[Monobactams\|monobactam]]
	** CLSI uses [[cefpodoxime]], [[ceftazidime]], [[aztreonam]], [[cefotaxime]], or [[ceftriaxone]]		**CLSI uses [[cefpodoxime]], [[ceftazidime]], [[aztreonam]], [[cefotaxime]], or [[ceftriaxone]]

	{\| class="wikitable"		{\| class="wikitable"
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	\|}		\|}

			*Organisms that screen positive have further testing to determine the presence of an ESBL
⚫	* ~~For~~ ~~organisms~~ ~~that~~ ~~screen~~ ~~positive,~~ ~~they~~ ~~are~~ ~~then~~ ~~tested for~~ third-generation [[Cephalosporins\|cephalosporin]] resistance that is attenuated by [[clavulanic acid]]
			*'''Class A''', for all organisms that screen positive,
⚫	** CLSI uses either [[ceftazidime]] or [[cefotaxime]], with and without [[clavulanic acid]]
		⚫	**A double-disc diffusion method is used to assess whether the third-generation [[Cephalosporins\|cephalosporin]] resistance that is attenuated by [[clavulanic acid]]
⚫	** An increase in the zone of ≥5 mm is diagnostic of ESBL production
		⚫	**CLSI uses either [[ceftazidime]] or [[cefotaxime]], with and without [[clavulanic acid]]
		⚫	**An increase in the zone of ≥5 mm is diagnostic of Class A ESBL production
			*'''Class B''', for organisms that are also resistant to [[carbapenems]]
			**See [[Carbapenemases]] for details
			*'''Class C''', for organisms that are non-susceptible to [[cefoxitin]]
			**A double-disc diffusion method is used to test if the results for [[cefoxitin]] are attenuated by [[cloxacillin]] (that is, if the isolate becomes even more susceptible)
			**An increase in the zone of ≥4 mm is positive for AmpC (Class C ESBL) phenotype
			*'''Class D''', difficult to identify with phenotypic testing

Aidan: Aidan moved page Extended-spectrum beta-lactamases to Extended-spectrum β-lactamases without leaving a redirect

2020-09-12T13:06:33Z

Aidan moved page Extended-spectrum beta-lactamases to Extended-spectrum β-lactamases without leaving a redirect

← Older revision	Revision as of 13:06, 12 September 2020
(No difference)

Aidan: Removed redirect to Β-lactamases

2020-09-12T13:06:22Z

Removed redirect to β-lactamases

← Older revision		Revision as of 13:06, 12 September 2020
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			== Background ==
	#REDIRECT [[Β-lactamases]]

			* Extended-spectrum β-lactamases (ESBLs) are generally defined as [[β-lactamases]] that hydrolyze [[penicillins]], first-, second-, and third-generation [[cephalosporins]], and [[aztreonam]], but not [[cephamycins]] or [[carbapenems]]
			* This definition excludes AmpC (which hydrolyze [[cephamycins]]) and carbapenemases (which hydrolyze [[carbapenems]])
			* Includes primarily Ambler Class A β-lactamases

			=== Identification ===

			* ESBLs are screened for by identifying organisms with increased MICs to one or more third-generation [[Cephalosporins\|cephalosporin]] or [[Monobactams\|monobactam]]
			** CLSI uses [[cefpodoxime]], [[ceftazidime]], [[aztreonam]], [[cefotaxime]], or [[ceftriaxone]]

			{\| class="wikitable"
			\|+Screening for ESBL production
			!Bacterium
			!Antibiotic
			!Disc Diffusion
			!Broth Microdilution
			\|-
			\| rowspan="5" \|[[Klebsiella pneumoniae]], [[Klebsiella oxytoca]], and [[Escherichia coli]]
			\|[[cefpodoxime]]
			\|≤17 mm
			\|≥8 μg/mL
			\|-
			\|[[ceftazidime]]
			\|≤22 mm
			\|≥2 μg/mL
			\|-
			\|[[aztreonam]]
			\|≤27 mm
			\|≥2 μg/mL
			\|-
			\|[[cefotaxime]]
			\|≤27 mm
			\|≥2 μg/mL
			\|-
			\|[[ceftriaxone]]
			\|≤25 mm
			\|≥2 μg/mL
			\|-
			\| rowspan="3" \|[[Proteus mirabilis]]
			\|[[cefpodoxime]]
			\|≤22 mm
			\|≥2 μg/mL
			\|-
			\|[[ceftazidime]]
			\|≤22 mm
			\|≥2 μg/mL
			\|-
			\|[[cefotaxime]]
			\|≤27 mm
			\|≥2 μg/mL
			\|}

			* For organisms that screen positive, they are then tested for third-generation [[Cephalosporins\|cephalosporin]] resistance that is attenuated by [[clavulanic acid]]
			** CLSI uses either [[ceftazidime]] or [[cefotaxime]], with and without [[clavulanic acid]]
			** An increase in the zone of ≥5 mm is diagnostic of ESBL production

Aidan: Aidan moved page Extended-spectrum beta-lactamases to Β-lactamases

2020-09-12T12:34:48Z

Aidan moved page Extended-spectrum beta-lactamases to β-lactamases

New page

#REDIRECT [[Β-lactamases]]