Strep G

Group G Streptococcus (GGS) appears under a microscope as Gram-positive, spherical to ovoid cocci arranged in pairs or long chains. They are often described as resembling a "string of beads" or "twisted berries" (from the Greek streptos meaning twisted and kokkos meaning berry).

Strep G is becoming an increasingly recognised issue in breeding cats, particularly in larger catteries and group-housed environments. In cats, “Strep G” usually refers to Streptococcus canis — a bacterium commonly carried by healthy cats (and also dogs) in the mouth, respiratory tract, skin, and reproductive tract.

Most of the time, Streptococcus canis lives harmlessly alongside its host. Problems occur when stress, crowding, viral disease, poor hygiene, or immune suppression allow the bacteria to become invasive. Young kittens and breeding queens are particularly vulnerable.

In breeding catteries, Strep G has been associated with a range of frustrating and sometimes heartbreaking reproductive problems, including:

• infertility or queens failing to call properly

• missed pregnancies

• miscarriage or resorption

• very small litters

• congenital defects: midlines, cleft, anencephaly, gastroschisis or omphalocele etc

• fading kittens

• neonatal septicaemia

• sudden kitten deaths

Some breeders also suspect it may contribute to poor kitten growth and queens failing to thrive during lactation, although these situations are often multifactorial.

The organism can spread through close contact between cats, respiratory secretions, birth fluids, contaminated environments, and possibly contaminated raw meat products. Because many healthy cats can carry the organism normally, it can be very difficult to completely eliminate from a breeding environment once established.

One important thing breeders should understand is that Streptococcus species remain remarkably sensitive to penicillin antibiotics. While there is often a temptation to reach for “stronger” or newer antibiotics, simple penicillin-based medications are usually highly effective against Strep G when used appropriately. In fact, veterinary microbiology labs commonly report excellent penicillin sensitivity in Streptococcus canis isolates. More powerful antibiotics are not necessarily better, and overuse of broad-spectrum drugs can contribute to resistance problems and disruption of normal bacterial balance.

One of the challenges with Strep G in cats is that it can be surprisingly difficult to isolate on routine swabs. Because Streptococcus canis may live normally on some cats, swab results can be inconsistent, intermittent, or misleading depending on where and when samples are taken, whether antibiotics have already been used, and how quickly samples reach the laboratory. In reproductive cases especially, breeders and veterinarians may develop a high clinical suspicion based on patterns within the cattery — such as infertility, small litters, fading kittens, or recurrent neonatal losses — even when cultures are negative or inconclusive. Be very suspicious if you're getting congenital defects in the first and/or middle kitten in birthing order - the kitten closest to the vagina during gestation. For this reason, many veterinarians will sometimes recommend empirical treatment using one of several recognised antibiotic protocols, often penicillin-based, alongside environmental management and hygiene improvements. Treatment plans should always be tailored to the individual cattery situation in consultation with your veterinarian.

As with many infectious diseases in breeding, management is usually about reducing overall disease pressure:

• maintaining excellent hygiene

• reducing stress and overcrowding

• supporting good nutrition - particularly if you raw feed (my next blog is about this issue).

• isolating sick animals early

• and working closely with a veterinarian for culture and sensitivity testing where needed

Strep G is rarely a simple “one cause, one fix” problem — but understanding the organism is an important step in managing healthy breeding cats and thriving kittens.