Summary Bacterial culture and susceptibility results were analysed from 233 horses with septic arthritis/tenosynovitis or osteomyelitis that developed after fracture repair. Antibiotics were deemed highly effective, effective or ineffective if ≤85%, 70–84.9% or <70% of the isolates were susceptible respectively. In total, 424 bacterial types were isolated; 386 were aerobic or facultative and 38 were anaerobic. Enterobacteriaceae (28.8%) were the most common bacterial group isolated, followed by non‐beta‐haemolytic streptococci (13.0%), coagulase‐positive staphylococci (11.8%), beta‐haemolytic streptococci (9.4%), and coagulase‐negative staphylococci (73%). The remainder of the organisms were other Gram‐negative (15.8%), other Gram‐positive (2.3%) and miscellaneous (2.6%) bacteria. Penicillin and ampicillin were highly effective against beta‐haemolytic streptococci, but were ineffective against other bacteria. Ampicillin was no more effective than penicillin against most bacteria. Amikacin was the most effective antibiotic against the wide range of bacteria isolated in this study. Amikacin was highly effective against coagulase‐positive staphylococci, Enterobacteriaceae and Pseudomonas and was effective against coagulase‐negative staphylococci and Actinobacillus. Gentamycin was not highly effective against any bacterial group; but was effective against coagulase‐positive and negative staphylococci, Pseudomonas, Salmonella and Actinobacillus. Kanamycin was ineffective against all bacteria with the exception of Actinobacillus. Cephalothin was highly effective against beta‐haemolytic streptococci, coagulase‐positive staphylococci and Actinobacillus and was effective against coagulase‐negative staphylococci. Cephalothin is a very useful antibiotic for Gram‐positive organisms, especially staphylococci, which are an important cause of iatrogenic infections. Trimethroprim‐sulphonamides were highly effective against Actinobacillus and were effective against coagulase‐positive staphylococci, beta‐haemolytic streptococci, non‐beta‐haemolytic streptococci and Rhodococcus equi. Due to the narrow spectrum of activity of trimethoprim‐sulphonamides against the common pathogenic organisms, these drugs should be used only after culture and susceptibility results are known. Erythromycin was highly effective against coagulase‐positive staphylococci, beta‐haemolytic streptococci and Rhodococcus equi and was effective against coagulase‐negative staphylococci. Chloramphenicol was effective against a wide range of organisms, but it cannot be recommended because of the human health hazard associated with handling this drug. Other less commonly used antibiotics were effective against some types of bacteria. The combination of a cephalosporin and amikacin provides the best coverage against the bacteria isolated in this study. These are the antibiotics that should be considered when treating horses with musculoskeletal infection before culture and susceptibility results are known. However, these drugs are not recommended for prophylaxis in ...

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All interventions decreased the number of microorganisms. Repopulation of normal flora occurred during and after treatment.

In this report we describe the historical, clinical, histopathological and microbiological features, as well as treatments and clinical outcome, of pyoderma where Pseudomonas aeruginosa alone was isolated on bacterial culture from lesional skin. Twenty dogs were included in this retrospective study. Seven dogs without prior history of systemic or skin disease presented with acute deep pseudomonal pyoderma characterized by a sudden onset of dorsal truncal pain. Skin lesions in these dogs consisted of erythematous papules, haemorrhagic bullae, ulcers and haemorrhagic crusts confined to the dorsum. An excellent clinical response was achieved with 3-4 weeks of treatment with oral fluoroquinolones. Thirteen dogs with a more gradual onset of skin lesions associated with pseudomonal pyoderma had a history of prior skin, ear or systemic disease and had previously been treated with antibiotics and/or immunomodulatory drugs. Skin lesions in these dogs were variable and similar to those described for superficial and deep staphylococcal pyoderma. In this group, one dog was euthanized prior to commencement of treatment, two dogs were lost to follow up, and 9 had resolution of lesions following treatment with topical silver sulfadiazine (one dog), fluoroquinolones (six dogs) or cephalexin (two dogs) administered orally for 3 to 12 weeks. Rod-shaped bacteria were not always detected on cytology. Histopathology of dogs with deep pseudomonal pyoderma was characterized by severe perforating suppurative folliculitis and furunculosis.

Medical records of 101 blood culture-confirmed bacteremic foals were reviewed to determine whether foals with Actinobacillus sp. bacteremia are affected at an earlier age, have more severe signs of disease, and have a worse prognosis than do foals with bacteremia of other causes. Thirty percent (30/101) of bacteremic foals had Actinobacillus sp. cultured, and these were 2 times more likely to die (crude odds ratio [OR CR ] 0.8, 4; P ϭ .14), with a survival rate of 43% (13/30) compared to the overall survival rate of 55% (56/101). When compared to other bacteremic foals, foals with actinobacillosis were 7 times more likely to have been sick from birth (adjusted odds ratio [OR ADJ ] 2, 26; P ϭ .003) and 6 times more likely to have diarrhea (OR ADJ 1, 22; P ϭ .009). By bivariate analysis, foals with Actinobacillus sp. bacteremia were 5 times more likely to have a sepsis score Ͼ11 (OR CR 1, 18; P ϭ .007), 6 times more likely to be obtunded (OR CR 2, 20; P ϭ .005), and 3 times more likely to have pneumonia (OR CR 1, 7; P ϭ .03). Furthermore, Actinobacillus sp. bacteremic foals were 27 times more likely to have a segmented neutrophil count Ͻ3.3 ϫ 10 9 cells/L (OR ADJ 4, 166; P Ͻ .0001) and were 4.5 times more likely to have a band neutrophil count Ͼ0.46 ϫ 10 9 cells/L (OR ADJ 1, 17; P ϭ .02) when compared to foals that had bacteremia caused by either gram-negative enteric or gram-positive organisms. Sepsis score was Յ11 in 49% (29/59) of bacteremia foals aged Ͻ13 days for which a discernible sepsis score was calculable. Results of this study should improve the diagnostic sensitivity of clinical examinations of neonatal foals, thereby facilitating treatment decisions.

Medical records of 101 blood culture-confirmed bacteremic foals were reviewed to determine whether foals with Actinobacillus sp. bacteremia are affected at an earlier age, have more severe signs of disease, and have a worse prognosis than do foals with bacteremia of other causes. Thirty percent (30/101) of bacteremic foals had Actinobacillus sp. cultured, and these were 2 times more likely to die (crude odds ratio [OR(CR)] 0.8, 4; P = .14), with a survival rate of 43% (13/30) compared to the overall survival rate of 55% (56/101). When compared to other bacteremic foals, foals with actinobacillosis were 7 times more likely to have been sick from birth (adjusted odds ratio [OR(ADJ)] 2, 26; P = .003) and 6 times more likely to have diarrhea (OR(ADJ) 1, 22; P = .009). By bivariate analysis. foals with Actinobacillus sp. bacteremia were 5 times more likely to have a sepsis score >11 (OR(CR) 1, 18; P = .007), 6 times more likely to be obtunded (OR(CR) 2, 20; P = .005), and 3 times more likely to have pneumonia (OR(CR) 1, 7; P = .03). Furthermore, Actinobacillus sp. bacteremic foals were 27 times more likely to have a segmented neutrophil count <3.3 X 10(9) cells/L (OR(ADJ) 4, 166: P < .0001) and were 4.5 times more likely to have a band neutrophil count >0.46 x 10(9) cells/L (OR(ADJ) 1, 17; P = .02) when compared to foals that had bacteremia caused by either gram-negative enteric or gram-positive organisms. Sepsis score was < or = 11 in 49% (29/59) of bacteremia foals aged <13 days for which a discernible sepsis score was calculable. Results of this study should improve the diagnostic sensitivity of clinical examinations of neonatal foals, thereby facilitating treatment decisions.

Coagulasepositive staphylococcal strains were heterogeneous among dogs with superficial bacterial folliculitis. In individual dogs, strains from multiple pustules were genotypically the same, and strains from pustules were genotypically the same as strains from carriage sites.

Bacteria introduced during a surgical procedure may be inhibited by elution of antibiotic from PMMA at the time of contamination.