Bacterial Infection Resulting in Open Wounds

My 11 year old Husky developed  a skin abbrasion out of nowhere in Oct 2023 which turned into a full blown open wound within a week. A culture test was done which found the presence of the bacteria Serratia Mercescens He was stitched up and put on Clindamycin and had since recovered. However on 1st Jan I noticed that the wound had appeared again where he had been stitched up and progressed within 2 days. Another culture test has been done and awaiting results but I expect it may the same bacterial infection I am at wits end at how to handle this as even his vet has not come across such a bacteria. Can anyone who may have experience in this help please!

Latest wound as at 3 Jan

Hello - I think that the first question to raise here, is how unusual it would be for any kind of bacteria to leap across a normal / healthy skin barrier by itself and spontaneously start an infection.   If it was able to do this, I wonder why it chose there and not, for example, the skin on the dogs' back or along the side, or on the bottom of the pads or the undercarriage?  And also, why did the bacteria choose to take hold in a line and not - say -  move outward from a central point?  This is what bacteria would normally do if introduced at a single spot, as evidenced by the pattern of colonies one sees on an agar dish, for example.

I suppose what I'm suggesting is that there may be a strong argument that the bacteria didn't come first and invade perfectly healthy skin, but moved in because of some weakness in the skin layer eg the skin fold in front of the hindlimb (which is low-oxygen and prone to rubbing, especially if it gets damp), or perhaps the back seam of a dog-coat if one was being worn, or a linear area damaged by scratching (perhaps coinciding with a yeast infection) or a feature of the hair-coat, for example.  Your vet, who will have assessed your dog in context, is the person to shed more light on this. They and any microbiologist who has been involved in the case, will have considered it.

I agree that it is tempting to assume that if an infection has taken hold once, then the same bacteria will decide to move in again.  This may not, however, necessarily be the case (although it is possible).  Rather, an area of the body weakened or damaged by a previous infection, may be more prone to getting infected in general, not just by that one type of bacteria.  Or perhaps it has been weakened by the same external factors that weakened it previously (eg a skin fold or itch) or by secondary issues from the first infection (eg dissolving sutures or disturbance to the blood flow).   It sounds like a good move to repeat culture and sensitivity at this point, so that any bacteria involved are identified and correctly targeted.  The lab microbiologists, who look at this sort of case all day, are likely to have seen or heard of similar situations if your vet hasn't; indeed, we vets are supported by research and case reports from all over the world.  In my experience, lab microbiologists can be extremely helpful in making recommendtions as to how to take a case forward and if you are in doubt as to the correct course of action, or how to handle it in the interim.  You could ask your vet whether they'd be happy to take advice from them.  I'm not sure whether any interim antibiotics or topic product has been used or reccommended, but if the aea is getting worse in the meantime then your vet should definitely be kept in the loop.  Taking regular photos is a good way of recording progress.  Please will you let us know how your dog gets on?