Table 1.
Cultivable microorganisms isolated from tracheal wash samples of horses with equine asthma
| Microorganism | Number of horses with bacteria after microbiological culture (direct) | Number of horses with bacteria after microbiological culture (after 48 h) | Number of horses with the given bacteria after both microbiological cultures |
|---|---|---|---|
| Acinetobacter baumannii | 3 | 0 | 3 |
| Acinetobacter lwoffii | 1 | 0 | 1 |
| Acinetobacter radioresistans | 1 | 0 | 1 |
| Actinobacillus spp. | 2 | 0 | 2 |
| Actinobacillus equuli | 2 | 1 | 3 |
| Actinobacillus rossii | 3 | 0 | 3 |
| Actinobacillus suis | 2 | 0 | 2 |
| Alcaligenes faecalis | 1 | 0 | 1 |
| Bacteroides fragilis | 2 | 0 | 2 |
| Bordetella bronchiseptica | 1 | 1 | 2 |
| Burkholderia cepacia | 1 | 0 | 1 |
| Burkholderia spp. | 1 | 0 | 1 |
| Clostridium perfringens | 1 | 0 | 1 |
| Clostridium tertium | 1 | 0 | 1 |
| Enterobacter hormaechei | 2 | 1 | 3 |
| Enterobacter ludwigii | 1 | 0 | 1 |
| Escherichia coli | 2 | 0 | 2 |
| Lactase⁻ Escherichia coli | 2 | 0 | 2 |
| Klebsiella aerogenes | 1 | 0 | 1 |
| Klebsiella oxytoca | 5 | 0 | 5 |
| Klebsiella pneumoniae | 11 | 0 | 11 |
| Kosakonia cowanii | 1 | 0 | 1 |
| Ochrobactrum anthropi | 1 | 0 | 1 |
| Pantoea agglomerans | 2 | 0 | 2 |
| Pasteurella spp. | 3 | 0 | 3 |
| Penicillium spp. | 1 | 1 | 2 |
| Prevotella sp. | 1 | 0 | 1 |
| Pseudomonas aeruginosa | 27 | 0 | 27 |
| Pseudomonas azotoformans | 1 | 0 | 1 |
| Pseudomonas fulva | 1 | 0 | 1 |
| Pseudomonas gessardii | 1 | 0 | 1 |
| Pseudomonas putida | 3 | 0 | 3 |
| Pseudomonas spp. other than P. aeruginosa | 7 | 0 | 7 |
| Pseudomonas synxantha | 1 | 0 | 1 |
| Rhodococcus equi | 2 | 0 | 2 |
| Serratia marcescens | 2 | 0 | 2 |
| Shewanella putrefaciens | 2 | 0 | 2 |
| Shigella spp. | 1 | 1 | 2 |
| Coagulase⁻ Staphylococcus | 1 | 0 | 1 |
| Staphylococcus sciuri subsp. sciuri | 0 | 1 | 1 |
| Staphylococcus aureus | 2 | 0 | 2 |
| Staphylococcus epidermidis | 0 | 1 | 1 |
| Staphylococcus xylosus | 1 | 0 | 1 |
| Stenotrophomonas maltophilia | 6 | 0 | 6 |
| α-haemolytic Streptococcus | 1 | 0 | 1 |
| Streptococcus canis | 1 | 0 | 1 |
| Streptococcus dysgalactiae | 2 | 0 | 2 |
| Streptococcus dysgalactiae subsp. equisimilis | 1 | 0 | 1 |
| Streptococcus equi subsp. zooepidemicus | 33 | 2 | 35 |
Fig. 1.
Number of culture-positive and culture-negative tracheal wash samples from horses with equine asthma
Fig. 2.
Distribution of the main bacterial genera in tracheal wash samples from horses with equine asthma
Table 2.
Antimicrobial substances tested against isolates from tracheal wash samples from horses with equine asthma
| Active substance | Number of cultures showing resistance | Total number of cultures challenged with the active substance | Percentage of cultures showing resistance |
|---|---|---|---|
| Amikacin | 8 | 71 | 11.3 |
| Cephalexin | 27 | 32 | 84.4 |
| Cefuroxime | 25 | 32 | 78.1 |
| Ceftiofur | 21 | 105 | 20 |
| Cephquinome | 21 | 108 | 19.4 |
| Erythromycin | 46 | 94 | 48.9 |
| Enrofloxacin | 14 | 137 | 10.2 |
| Gentamicin | 24 | 95 | 25.3 |
| Marbofloxacin | 12 | 135 | 8.89 |
| Penicillin G | 49 | 108 | 45.4 |
| Rifampicin | 31 | 35 | 88.6 |
| Trimethoprim + sulfamethoxazole | 40 | 124 | 32.3 |
| Ciprofloxacin | 1 | 5 | 20 |
| Polymyxin B | 0 | 5 | 0 |
| Colistin | 0 | 2 | 0 |
| Tobramycin | 3 | 12 | 25 |
| Clindamycin | 10 | 10 | 10 |
| Amoxicillin with clavulanic acid | 3 | 6 | 50 |
| Amoxicillin | 9 | 32 | 28.1 |
| Ampicillin | 17 | 69 | 24.6 |
| Ceftazidime | 5 | 37 | 13.5 |
| Cefepime | 0 | 2 | 0 |
| Metronidazole | 1 | 5 | 20 |
| Piperacillin | 0 | 2 | 0 |
| Sulfadiazine + trimethoprim | 14 | 86 | 16.3 |
| Doxycycline | 10 | 46 | 21.7 |
| Azithromycin | 9 | 56 | 16.1 |
| Oxytetracycline | 2 | 25 | 8 |
| Tetracycline | 27 | 63 | 42.9 |
| Cephapirin | 2 | 37 | 5.4 |
| Cefazolin | 6 | 41 | 14.6 |
| Ticarcillin with clavulanic acid | 10 | 18 | 55.6 |
| Streptomycin | 6 | 17 | 35.3 |
| Pefloxacin | 0 | 1 | 0 |
| Florfenicol | 0 | 1 | 0 |
Table 3.
Antimicrobial agents to which the greatest susceptibility and resistance was found among the bacteria most frequently isolated from horses with equine asthma
| Bacterial species | Antimicrobial to which the bacteria was susceptible | Antimicrobial to which the bacteria was resistant |
|---|---|---|
| Streptococcus equi subsp. zooepidemicus | ceftiofur (n = 35) | tetracycline (n = 18) |
| cephquinome (n = 35) | ||
| erythromycin (n = 35) | ||
| enrofloxacin (n = 22) | ||
| marbofloxacin (n = 28) | ||
| sulfamethoxazole/trimethoprim (n = 29) | ||
| ampicillin (n = 29) | ||
| sulfadiazine/trimethoprim (n = 33) | ||
| penicillin G (n = 34) | ||
| azithromycin (n = 35) | ||
| cephapirin (n = 27) | ||
| cefazolin (n = 27) | ||
| Pseudomonas aeruginosa | amikacin (n = 24) | gentamicin (n = 11) enrofloxacin (n = 9) |
| gentamicin (n = 15) | ||
| marbofloxacin (n = 19) | ||
| ceftazidime (n = 21) | ||
| Klebsiella pneumoniae | ceftiofur (n = 10) | single resistant strains to different antimicrobials |
| cefquinome (n = 10) | ||
| enrofloxacin (n = 8) | ||
| marbofloxacin (n = 9) | ||
| gentamicin (n = 9) | ||
| sulfamethoxazole/trimethoprim (n = 8) | ||
| sulfadiazine/trimethoprim (n = 6) |
Figure 3.
Airway neutrophil percentage according to the number of bacterial isolates recovered from tracheal wash samples from horses with equine asthma