Monobactams are monocyclic and bacterially-produced

β-lactam antibiotic β-lactam antibiotics (beta-lactam antibiotics) are antibiotics that contain a beta-lactam ring in their chemical structure. This includes penicillin derivatives ( penams), cephalosporins and cephamycins ( cephems), monobactams, carbapenems and ...

s. The

β-lactam A beta-lactam (β-lactam) ring is a four-membered lactam. A ''lactam'' is a cyclic amide, and ''beta''-lactams are named so because the nitrogen atom is attached to the β-carbon atom relative to the carbonyl. The simplest β-lactam possible is ...

ring is not fused to another ring, in contrast to most other β-lactams. Monobactams are effective only against aerobic

Gram-negative bacteria Gram-negative bacteria are bacteria that do not retain the crystal violet stain used in the Gram staining method of bacterial differentiation. They are characterized by their cell envelopes, which are composed of a thin peptidoglycan cell wa ...

(e.g., ''

Neisseria ''Neisseria'' is a large genus of bacteria that colonize the mucosal surfaces of many animals. Of the 11 species that colonize humans, only two are pathogens, ''N. meningitidis'' and '' N. gonorrhoeae''. ''Neisseria'' species are Gram-negativ ...

'', ''

Pseudomonas ''Pseudomonas'' is a genus of Gram-negative, Gammaproteobacteria, belonging to the family Pseudomonadaceae and containing 191 described species. The members of the genus demonstrate a great deal of metabolic diversity and consequently are able ...

'').

Siderophore Siderophores (Greek: "iron carrier") are small, high-affinity iron- chelating compounds that are secreted by microorganisms such as bacteria and fungi. They help the organism accumulate iron. Although a widening range of siderophore functions is n ...

-conjugated monobactams show promise for the treatment of multi drug-resistant pathogens.

Aztreonam Aztreonam, sold under the brand name Azactam among others, is an antibiotic used primarily to treat infections caused by gram-negative bacteria such as '' Pseudomonas aeruginosa''. This may include bone infections, endometritis, intra abdomi ...

is a commercially available monobactam antibiotic. Other examples of monobactams are tigemonam, nocardicin A, and

tabtoxin Tabtoxin, also known as wildfire toxin, is a simple monobactam phytotoxin produced by ''Pseudomonas syringae''. It is the precursor to the antibiotic tabtoxinine β-lactam (TBL). It is produced by: * Pseudomonas syringae pv. tabaci, the causal age ...

. Adverse effects to monobactams can include skin rash and occasional abnormal liver functions. Monobactam antibiotics exhibit no IgE cross-reactivity reactions with

penicillin Penicillins (P, PCN or PEN) are a group of β-lactam antibiotics originally obtained from ''Penicillium'' moulds, principally '' P. chrysogenum'' and '' P. rubens''. Most penicillins in clinical use are synthesised by P. chrysogenum using ...

but have shown some cross reactivity with

cephalosporin The cephalosporins (sg. ) are a class of β-lactam antibiotics originally derived from the fungus '' Acremonium'', which was previously known as ''Cephalosporium''. Together with cephamycins, they constitute a subgroup of β-lactam antibioti ...

s, most notably

ceftazidime Ceftazidime, sold under the brand name Fortaz among others, is a third-generation cephalosporin antibiotic useful for the treatment of a number of bacterial infections. Specifically it is used for joint infections, meningitis, pneumonia, sepsis, ...

, which contains an identical side chain as aztreonam. Monobactams can trigger seizures in patients with history of seizures, although the risk is lower than with penicillins.

References

External links

* {{antibiotic-stub