Microbiology

Extended-spectrum beta-lactamase producing Gram-negative bacteria

Extended-spectrum beta-lactamase producing Gram-negative bacteria

Extended spectrum -lactamases (ESBL)

Industry of interest: Healthcare

Classification: Enzymes conferring resistance to extended spectrum-lactam antibiotics

Microbiology: Multidrug-resistance has been increasing amongst Gram-negative bacteria, which has been strongly associated with the production and chromosomal- and plasmid- encoded extended spectrum -lactamases (Bush, 2007). Some of the most common EBSL-producing bacteria s include Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis and Pseudomonas aeruginosa.
 

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Biology

Habitat and transmission: ESBL-producing microorganisms each have their own preferred ecological niches. However, these microorganisms have been frequently associated with hospital-acquired infections and increasingly community-associated infections (Paterson, 2005). ESBL-producing bacteria frequently contaminate medical apparatus and in-dwelling devices such as catheters. Risk factors for transmission include broad-spectrum antibiotic usage and prolonged hospital stays. ESBL-producing bacteria can be spread through person-to-person contact and from the environment because ESBL-producing bacteria can be shed into the environment by symptomatic and asymptomatic carriers (Paterson, 2005).

Treatment and antibiotic resistance: Increasing use of penicillins has driven b-lactam resistance in the clinical setting. b-lactamases are enzymes produced by ESBL bacteria that can hydrolyse the b-lactam chemical bond (oxyamino group), rendering the molecules incapable of inactivating bacteria (Paterson, 2005). Antibiotic treatment of ESBL-producing bacteria is extremely difficult and has high failure rates, although ESBL- producing bacteria are inhibited by clavulinic acid (Falagas and Karageorgopoulos, 2009). However, serious ESBL-bacterial infections can be treated with carbapenems.

Prevention and control: The most important factor in the prevention and control of ESBL-producing bacteria is the careful selection and use of antibiotics that will inactivate the bacteria without inducing greater antibiotic resistance. However, more general infection control strategies such as improving hand-hygiene compliance, environmental decontamination, and medical device sterilisation are all important in reducing the the transmission of ESBL-producing bacteria (Falagas and Karageorgopoulos, 2009).

Symptoms/Effects

Disease and symptoms: EBSL-producing bacteria have been found to cause infection, primarily in the seriously ill such as patients in intensive care units (ICUs). Infections generally originate in the urinary tract but can also cause secondary bloodstream infections and intra-abdominal infections (Falagas and Karageorgopoulos, 2009).

Technical

References:

Bush K. (2010
) Bench-to-bedside review: The role of -lactamases in antibiotic-resistant Gram-negative infections. Crit care. 14(3): 224.

Fallagas M.E. and Karageorgopoulos D.E. (2009) Extended-spectrum beta-lactamase-producing organisms. J Hosp Infect. 73(4): 345-354.

Paterson D.L. and Bonomo R.A. (2005) Extended-spectrum beta-lactamase: a clinical update. Clin Microbiol Rev. 18(4): 657-686.
 

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