From our colony to your sofa
Mycoplasma: The Fellow Traveller
The smallest bacteria, usually part of a gang.
Last reviewed
The smallest bacteria, usually part of a gang.
Last reviewed
Mycoplasmas are the smallest free living bacteria, odd little organisms without cell walls, and in cats they mostly work as accomplices: joining viral cat flu to deepen conjunctivitis and snuffles rather than starting fires alone.
That is why they turn up in the same places as everything else in this shelf: young cats, group living, and any cat whose defences are busy fighting something viral.
Think of mycoplasma when eye and nose trouble will not fully clear: a low grade conjunctivitis that simmers on after the flu has passed, persistent mild discharge, or a snuffle that improves with treatment then drifts back. Nothing dramatic, everything lingering.
One cousin deserves a line of its own: haemotropic mycoplasmas live on red blood cells, spread mainly by fleas, and cause anaemia, pale gums, lethargy and weakness. Different disease, same family name, and one more reason flea control is health care.
The good news doubles: mycoplasmas respond well to specific antibiotic families your vet can prescribe, and identifying them has become routine with modern swab tests. A lingering eye or nose problem that finally meets the right drug often clears with almost suspicious speed.
The blood form is equally treatable once found on a blood test, alongside flea treatment for the whole household, since the messenger matters as much as the message.
Mycoplasmas are bacteria built without a cell wall, which sounds like trivia until you remember that several major antibiotic families work precisely by wrecking cell walls. Against mycoplasma those drugs swing at nothing, which is why a stubborn infection can shrug off a perfectly sensible first prescription.
Vets know the workaround: antibiotic families that attack the machinery inside the organism instead. The owner’s translation is simply that treatment failure here is often a mismatch, not a mystery, and the fix is identification followed by the right family, not more of the wrong one.
Pure solo mycoplasma disease is uncommon; its favourite role is deepening someone else’s damage. Viral flu roughens the airway lining, chlamydia inflames the eye, and mycoplasma moves into the disturbed ground, extending and worsening what would have healed.
That is why it turns up in swab results from chronic cases more than fresh ones, and why treating it can be the move that finally lets a lingering problem close. Think of it less as the arsonist, more as the squatter who keeps the fire smouldering.
The haemotropic mycoplasmas are a different branch of the family with a different crime: they live on red blood cells and destroy them, causing anaemia that ranges from silent to severe. The route in is blood to blood, with fleas the prime suspects and cat fights a strong second, which writes the risk profile: outdoor cats, entire toms, flea burdens.
Diagnosis is a PCR blood test, treatment combines the right antibiotic family with support for the anaemia, and prevention is the least glamorous sentence in this library: keep the flea control current. Pale gums plus lethargy in any at risk cat should put this cousin on the vet’s list.
The classic mycoplasma story is the snuffle that will not finish: a cat flu episode that improves, plateaus and grumbles on for weeks, or the eye that clears and re inflames in cycles. The viruses started the fire; the mycoplasma keeps raking the embers.
That pattern is precisely the moment to return to the vet rather than extend home nursing: lingering means the microbial cast has probably changed, and what treats a virus does not touch this accomplice. Naming the second infection is how three week colds stop becoming three month ones.
Mycoplasmas are regular co conspirators in feline conjunctivitis: red, weepy, gummy eyes, often alongside or after respiratory signs, sometimes hopping from one eye to the other. On their own they are usually mild; teamed with herpesvirus or chlamydophila they make eye trouble stubborn.
Practically, this is why a stubborn eye earns swabs rather than serial guesswork, and why prescribed eye treatment runs its full course even after the gunk clears. The organisms retreat before they surrender, and early stopping invites the relapse cycle these infections are famous for.
Treatment succeeds on two conditions: the right drug class, since these wall less organisms ignore several everyday antibiotics, and the full prescribed duration, since mycoplasmas are slow burning and early symptom relief arrives well before actual clearance.
The relapse pattern owners report, better in four days, stopped the tablets, sick again in a fortnight, is this biology in action. Give every dose to the end, use the follow up if offered, and report any relapse promptly, because relapses shape what the vet reaches for next.
First episodes of mild snuffles are often treated on the clinical picture, reasonably. Testing earns its keep in the stubborn cases: respiratory PCR panels on swabs that name mycoplasma and its usual co conspirators in one pass, turning serial guesswork into a targeted plan.
Multi cat households and breeding environments lean on the same tool: knowing exactly which organisms are circulating decides isolation, hygiene and treatment for the group, not just the patient. One swab that names the enemy is cheaper than a month of wrong assumptions.
Mycoplasmas are minimalist bacteria that work as accomplices: rarely the sole villain, often the reason a snuffle or eye infection lingers past its welcome. They lack the cell wall many antibiotics target, so treatment is a specific choice and a full course, on your vet’s prescription. A cold that will not end is the classic calling card, and it is fixable.
The respiratory and eye species involved here are feline adapted, and human infection is not a practical concern for healthy households. Ordinary hygiene around a snuffly cat covers it.
Same family, different job: blood borne relatives attack red blood cells and cause anaemia, a distinct disease with its own name and treatment. This guide’s organisms work the airways and eyes.
Close contact with infected cats, shared air and grooming in ordinary feline social life; many cats carry small populations harmlessly until a virus or stress opens the door. It is an opportunist, not an invader.
Because several common antibiotic families target the cell wall mycoplasmas famously lack, and courses aimed at other bacteria pass straight through them. The fix is the specific class your vet prescribes for this organism.
It is one of the classic reasons, alongside herpesvirus, and the cycling pattern fits. Ask about swabbing on the next flare so treatment can be matched to the actual culprit.
Usually mild solo, mainly a nuisance amplifier of other infections, but in kittens, seniors and immune suppressed cats it deserves full respect and prompt treatment. Context decides its rank.
During active symptoms, sensible separation and bowl hygiene protect housemates, exactly as with any respiratory infection. Your vet will scale the strictness to your household’s cats.
Effectively yes: stress dents local immunity and lets a resident population expand, often alongside a herpes flare. It is one more entry on the list of reasons calm routines are medicine.
The flea connection to the blood form makes our flea guide required reading, and stubborn eyes are decoded in conjunctivitis.
Beyond our library, International Cat Care covers this with owner friendly clarity, and Cornell Feline Health Center adds the clinical depth. And to see the culprit itself, the Mycoplasma page carries the photographs and the science.