Table 1
Interpretive criteria for Enterobacteriaceae using disc diffusion susceptibility testing reported as inhibition zone diameters (mm)
| Antimicrobial agent | Disc (μg) | Susceptible | Intermediate | Resistant |
|---|---|---|---|---|
| Ampicillin | 10 | ≥17 | 14–16 | ≤13 |
| Amoxicillin-clavulanic acid | 30 (20/10) | ≥18 | 14–17 | ≤13 |
| Cefoxitin | 30 | ≥18 | 15–17 | ≤14 |
| Ceftriaxone | 30 | ≥23 | 20–22 | ≤19 |
| Streptomycin | 10 | ≥15 | 12–14 | ≤11 |
| Kanamycin | 30 | ≥18 | 14–17 | ≤13 |
| Amikacin | 30 | ≥17 | 15–16 | ≤14 |
| Gentamicin | 10 | ≥15 | 13–14 | ≤12 |
| Tetracycline | 30 | ≥15 | 12–14 | ≤11 |
| Chloramphenicol | 30 | ≥18 | 13–17 | ≤12 |
| Sulphafurazole | 300 | ≥17 | 13–16 | ≤12 |
| Trimethoprim-sulphamethoxazole | 25 (1.25/23.75) | ≥16 | 11–15 | ≤10 |
| Nalidixic acid | 30 | ≥19 | 14–18 | ≤13 |
| Ciprofloxacin | 5 | ≥26 | 22–25 | ≤21 |
Table 2
Identification by sequencing of the 16S ribosomal RNA (16S rRNA) gene and matrix-assisted laser desorption/ionisation–time-of-flight mass spectrometry (MALDI-TOF MS) of 12 Enterobacteriaceae isolates other than E. coli from raccoons in the Madrid region of Spain
| Isolate reference | Sequencing of the 16S rRNA gene | MALDI-TOF MS | |||
|---|---|---|---|---|---|
| Identification | Similarity (%) | First identification (score value) a | Second identification (score value) a | Consistency b | |
| 23147c | Enterobacter hormaechei subsp. hoffmannii | 98.8 | Enterobacter cloacae (2.296) | Escherichia coli (2.254) | D |
| 23167b | Citrobacter freundii | 98.8 | Citrobacter braakii (2.458) | Citrobacter freundii (2.337) | C |
| 23353b | Citrobacter portucalensis | 99.3 | Citrobacter braakii (2.467) | Citrobacter freundii (2.282) | D |
| 23375a | Citrobacter portucalensis | 99.5 | Citrobacter freundii (2.289) | Citrobacter braakii (2.261) | D |
| 23375c | Raoultella ornithinolytica | 99.9 | Raoultella ornithinolytica (2.399) | Raoultella planticola (2.301) | B |
| 23380a | Citrobacter murliniae | 99.2 | Citrobacter braakii (2.397) | Citrobacter freundii (2.154) | D |
| 23380b | Hafnia paralvei | 99.1 | Hafnia alvei (2.292) | Dickeya chrysanthemi (1.504) | D |
| 23380c | Hafnia paralvei | 99.1 | Hafnia alvei (2.292) | Dickeya chrysanthemi (1.504) | D |
| 23381a | Raoultella ornithinolytica | 99.7 | Raoultella ornithinolytica (2.383) | Raoultella planticola (2.245) | B |
| 23381c | Citrobacter gillenii | 99.0 | Citrobacter gillenii (2.460) | Citrobacter freundii (2.122) | B |
| 26650a | Citrobacter gillenii | 99.5 | Citrobacter gillenii (2.408) | Citrobacter freundii (2.140) | B |
| 26650c | Citrobacter gillenii | 99.5 | Citrobacter gillenii (2.408) | Citrobacter freundii (2.140) | B |
[i] a – First and second identification best matches with their respective score values provided by the Biotyper identification list
b – Consistency ranking list of the first two best matches: B, the correct species is the first ranked but a different species is in the second rank also with a score value ≥ 2.000; C, the first and second matches have score values ≥2.000 but the correct species is the second ranked; D, the first matches have score values > 2.000 and the second matches have scores > or <2.000, but the correct species is neither the first nor second ranked
Table 3
Antimicrobial susceptibility of 12 Enterobacteriaceae isolates other than E. coli from raccoons in the Madrid region of Spain
| Isolate reference | Identification | Susceptibility to: | |||||||
|---|---|---|---|---|---|---|---|---|---|
| AMP | AMC | FOX | ST | K | SF | NA | CIP | ||
| 23147c | Enterobacter hormaechei subsp. hoffmannii | R | R | R | S | S | I | S | S |
| 23167b | Citrobacter freundii | R | R | R | S | S | I | S | S |
| 23353b | Citrobacter portucalensis | R | R | R | S | S | I | I | I |
| 23375a | Citrobacter portucalensis | R | R | R | S | S | S | S | S |
| 23375c | Raoultella ornithinolytica | R | S | S | R | S | S | R | S |
| 23380a | Citrobacter murliniae | S | S | S | I | S | I | S | S |
| 23380b | Hafnia paralvei | R | R | S | I | S | S | S | S |
| 23380c | Hafnia paralvei | R | R | S | I | S | S | S | S |
| 23381a | Raoultella ornithinolytica | R | S | S | S | S | I | S | I |
| 23381c | Citrobacter gillenii | I | S | S | S | R | R | S | I |
| 26650a | Citrobacter gillenii | R | S | S | S | S | I | S | S |
| 26650c | Citrobacter gillenii | R | S | S | S | S | I | S | S |
[i] AMP – ampicillin; AMC – amoxicillin-clavulanic acid; FOX – cefoxitin; ST – streptomycin; K – kanamycin; SF – sulphafurazole; NA – nalidixic acid; CIP – ciprofloxacin; S – susceptible; I – intermediate; R – resistant. All isolates were susceptible to ceftriaxone, amikacin, gentamicin, tetracycline, chloramphenicol and trimethoprim-sulphamethoxazole