Antibiotics Commonly Used In Animal Shelters
Antibiotic use is very important when medically indicated for the treatment of susceptible pathogens (usually bacterial.)
You should only treat a dog or cat with antibiotics if you are pretty sure that an infection is present. The best way to determine if an infection is present is through a laboratory culture of an appropriate sample.
Culturing has the additional advantages of confirming the identity of the bacteria and determining which antibiotics are appropriate choices for treatment. A temporary expedient while waiting for cultures is to look at a smear of a sample taken from the infected area under a microscope. This is important, because it helps you determine if there are several bacteria in a sample or if there are bacteria that are not growing.
The next "best" indication of infection would be if the animal is sick in a way that suggests an infection: fever, elevated white blood cells, inflammation, x-rays or other tests with results that suggest certain types of infection. Finally, PCR and other DNA-based identification tests are great tools to use to determine if an infection is present (and can be useful for bacteria that cannot be grown in the lab) However, with this method you do not obtain an isolate for drug-testing and dead bacteria are often still PCR-positive.
Adverse effects of antibiotics
There are three main problems with using antibiotics. One is direct medical side-effects such as toxic effects (e.g. aminoglycoside antibiotics are toxic to kidney cells) or allergies (which can be life-threatening).
The second is that your antibiotic could kill the normal flora and leave the patient more vulnerable to pathogens (often which are resistant to antibiotics).
The last problem is that using antibiotics genetically selects for antibiotic resistance in your bacteria. It may develop if the bacteria has a genetic mutation, but this is an uncommon source of the problem.
we know that almost all urinary tract infections respond very well to most broad-spectrum antibiotics...
Penicillins: Cidal, disrupt cell wall. Spectrum: broad except bacteria with specific resistance.Main use in cats: general use. Side-effects: allergy, fever, rash, loss of white blood cells, anemia, GI upset.
* Amoxicillin: comparable to ampicillin but absorbed from gut better.
* Ampicillin: better for some gram-negative bacteria than Pen G but not as good for anaerobes. Penicillin G, procaine pen G (long-acting injection)
* Penicillin V: slightly less effective than Pen G but better absorbed when given orally.
* Oxacillin: for penicillin-resistant Staphylococci.
* Amoxicillin/clavulanate: overcomes much resistance, restores broad spectrum.
* Ticarcillin: injectable, especially for severe Pseudomonas.
Aminoglycosides: Cidal, inhibit protein synthesis. Spectrum: gram-negative, some gram-positive bacteria. Main use in cats: severe or resistant gram-negative bacteria, must be injected (except neomycin). Side-effects: severe kidney damage, hearing loss, facial swelling, nerve damage.
Amikacin, Gentamycin, Neomycin: Not given injectably because of severe kidney damage, not absorbed into bloodstream if eaten/used as enema/applied to skin but will treat bacteria in GI tract, on skin.
Cephalosporins: Cidal, disrupt cell wall. Spectrum, first-generation: gram-positive bacteria, anaerobic bacteria. Spectrum, third generation: excellent gram-negative, some gram-positive. Main use in cats: skin disease, susceptible infections. Side-effects: allergy (cross-reactions with penicillins), GI disease, diarrhea
* Cefadroxil (Cefa-tabs): 1st gen.
* Cephalexin (Keflex): 1st gen.
* CephCephalothin (Keflin): 1st gen, injectable.alothin (Keflin): 1st gen, injectable.
* Ceftiofur (Naxcel): 3rd generation, injectable.
Tetracyclines: Static, inhibit protein synthesis. Spectrum: broad-spectrum (but many resistant bacteria), rickettsias, other bacteria that live in cells. Main use in cats: hemobartonella, susceptible bacteria. Side-effects: GI upset, discolored teeth, liver/kidney disease, hair loss, photosensitivity.
* Doxycycline: much more expensive liquid form, fewer doses/day, different target organs.
Clindamycin (Antirobe): Static or cidal, disrupts protein synthesis. Spectrum: gram-positive bacteria, anaerobic bacteria. Main use in cats: dental disease, abscesses, diarrhea. Side-effects: GI upset.
Erythromycin: Mostly static, inhibits protein synthesis of bacteria. Spectrum: gram-positive bacteria, rickettsias, Chlamydophila, et al. Main use in cats: Giardia, anaerobes, diarrhea. Side-effects: neurological problems, white blood cell reduction, liver damage, blood in urine, vomiting and diarrhea.
Tylosin (tylan): Static, inhibits protein synthesis of bacteria. Spectrum: variable. Main use in cats: diarrhea, inflammatory bowel disease. Side-effects: few.
Enrofloxacin (baytril): Cidal, inhibits DNA gyrase, synthesis. Spectrum: gram-negative bacteria, Brucella, Chlamydophila, Staph, Mycoplasma. Main use in cats: various infections resistant to other antibiotics. Side-effects: cartilage damage in young animals, urine crystals, GI disease.
Sulfa drugs: Static, interferes with enzyme systems essential to normal metabolic and growth patterns. Side effects: nausea, vomiting, fever, anemia, leukopenia and irritation of the liver or kidneys.
* Trimethoprim sulfa (diazine or methoxazole)(TMS, SMX-TMP et al.): sulfa is static, combo is cidal, block thymidine (an important enzyme) in the bacteria. Spectrum: broad, many bacteria, some protozoa. Main use in cats: many infections. Side-effects: dry eye, liver disease, GI disease, anemia, allergy.
Metronidazole (Flagyl): cidal, disrupts DNA synthesis? Spectrum: anaerobic bacteria, some protozoa (Giardia, amoebas). Main use in cats: Giardia, anaerobes, diarrhea. Side-effects: neurological problems, white blood cell reduction, liver damage, blood in urine, vomiting and diarrhea.
Rifampin (Rifadin or Rimactane): cidal or static, inhibits RNA polymerase. Spectrum: intracellular bacteria (Mycobacteria, Staph, Rhodococcus, Chlamydophila et al.), some fungi, some viruses. Main use in cats: with anti- fungals in brain fungal disease. Side-effects: discolored tears and urine, GI upset, liver damage (very high doses).
Commonly used antibiotics in animal shelters
Antibiotic susceptibility patterns for positive bordetella cultures submitted to the Veterinary Medical Teaching Hospital (VMTH) at Davis
Shelter samples *VMTH Samples
(including all shelter samples)
Antibiotic
Dogs
Cats
Dogs and Cats
VACCINES
Amoxicillin/clavamox
81.2%(16)
29.1%(55)
59%(78)
100%(3)
Ampicillin
28.6%(14)
3.6%(56)
7.6%(79)
0%(3)
Timentin
85.7%(14)
66.7%(57)
71.1%(76)
100%(3)
Amikacin
100%(7)
82.5%(57)
85%(80)
100%(3)
Gentamicin
100%(17)
87.7%(57.7)
90%(80)
100%(3)
Chloramphenicol
68.8%(16)
80.4%(51)
75.3%(73)
100%(3)
Enrofloxacin
87.5%(16)
93%(57)
90.5%(74)
100%(3)
Tetracycline
100%(16)
98.3%(58)
98.8%(80)
100%(3)
Trimethoprim Sulfa
70.1%(17)
94.7%(57)
87.5%(80)
100%(3)
*Only a small number of positive Bordetella cultures are listed here.
UC DAVIS http://www.sheltermedicine.com/portal/is_antibiotic_use_primer.shtml
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