Neisseria lactamica is a gram-negative

Gram-negative

Gram-negative bacteria are bacteria that do not retain crystal violet dye in the Gram staining protocol. In a Gram stain test, a counterstain is added after the crystal violet, coloring all Gram-negative bacteria with a red or pink color...

 diplococcus

Diplococcus

A diplococcus is a round bacterium that typically occurs in the form of two joined cells. Examples are Streptococcus pneumoniae, Moraxella catarrhalis, Neisseria gonorrhoeae and Neisseria meningitidis...

 bacterium. It is strictly a commensal

Commensalism

In ecology, commensalism is a class of relationship between two organisms where one organism benefits but the other is neutral...

 species of the nasopharynx

Nasopharynx

The nasopharynx is the uppermost part of the pharynx. It extends from the base of the skull to the upper surface of the soft palate; it differs from the oral and laryngeal parts of the pharynx in that its cavity always remains patent .-Lateral:On its lateral wall is the pharyngeal ostium of the...

. Uniquely among the Neisseria

Neisseria

The Neisseria is a large genus of commensal 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 often cause asymptomatic infections, a commensal-like behavior...

they are able to produce β-D-galactosidase

Beta-galactosidase

β-galactosidase, also called beta-gal or β-gal, is a hydrolase enzyme that catalyzes the hydrolysis of β-galactosides into monosaccharides. Substrates of different β-galactosidases include ganglioside GM1, lactosylceramides, lactose, and various glycoproteins...

 and ferment lactose .

This species is most commonly carried by young children. There is an inverse relationship between colonisation by N. lactamica and Neisseria meningitidis

Neisseria meningitidis

Neisseria meningitidis, often referred to as meningococcus, is a bacterium that can cause meningitis and other forms of meningococcal disease such as meningococcemia, a life threatening sepsis. N. meningitidis is a major cause of morbidity and mortality during childhood in industrialized countries...

. Carriage of N. lactamica has been associated with decreased incidence of invasive meningococcal disease.

External links

• [ftp://ftp.sanger.ac.uk/pub/pathogens/Neisseria/lactamica/ Genome sequence of Neisseria lactamica (an ST640 strain).] Published on the Wellcome Trust Sanger Institute
  Sanger Institute
  The Wellcome Trust Sanger Institute is a non-profit, British genomics and genetics research institute, primarily funded by the Wellcome Trust....
  
  ftp server.

• Sequence data from the Neisseria lactamica Y92-1009 genome sequencing project.

• Sequence data from the Neisseria lactamica ATCC 23970 genome sequencing project.