The growth of<unk>  colonies on New York City agar<unk>  in cerebrospinal fluid (CSF) seen by Gram stain at 1000x magnification A small amount of cerebrospinal fluid (CSF) is sent to the laboratory as soon as possible for analysis. The diagnosis is suspected, when Gram-negative diplococci are seen on Gram stain of a centrifuged sample of CSF; sometimes they are located inside white blood cells. The microscopic identification takes around 1–2 hours after specimen arrival in the laboratory. The gold standard of diagnosis is microbiological isolation of<unk>  by growth from a sterile body fluid, which could be CSF or blood. Diagnosis is confirmed when the organism has grown, most often on a chocolate agar plate, but also on Thayer-Martin agar. To differentiate any bacterial growth from other species a small amount of a bacterial colony is tested for oxidase, catalase for which all clinically relevant Neisseria show a positive reaction, and the carbohydrates maltose, sucrose, and glucose, in which<unk>  will ferment that is, utilize the glucose and maltose. Finally, serology determines the subgroup of the<unk> , which is important for epidemiological surveillance purposes; this may often only be done in specialized laboratories. The above tests take a minimum of 48–72 hours turnaround time for growing the organism, and up to a week more for serotyping. Growth can and often does fail, either because antibiotics have been given preemptively, or because specimens have been inappropriately transported, as the organism is extremely susceptible to antibiotics and fastidious in its temperature, and growth medium requirements. Polymerase chain reaction (PCR) tests where available, mostly in industrialized countries, have been increasingly used; PCR can rapidly identify the organism, and works even after antibiotics have been given.
Neisseria meningitidis
Bordetella pertussis
Haemophilus influenzae
Rhodococcus equi
Kingella kingae
Streptococcus bovis
Streptococcus pyogenes
Neisseria flavescens