You will be shown a paragraph from a biomedical research article. Your task is to extract all drug combinations appearing in a specific sentence within in the paragraph. Each drug combination should be assigned to one of the following three categories:

- POS: Indicates a positive interaction between the drugs in the combination; for instance, drugs that have an additive or synergistic effect.
- NEG: Indicates a negative interaction between the drugs in the combination; for instance, combining these drugs might result in adverse side effects, or might reduce their efficacy.
- COMB: Indicates that the drugs are given in combination, but the type of interaction between the drugs cannot be determined based on the provided context.

Please format your answer as a json array. Each entry in the array should itself be an array formatted as [<drug_1>, <drug_2>, ..., <drug_n>, <category>] where <category> is one of the three categories listed above and <drug_1>, ..., <drug_n> are drug names copied verbatim from the input sentence. Different combinations may involve different numbers of drugs; in other words, the `n` in <drug_n> may vary.

As an example, the following output describes two extracted drug combinations; one between two drugs, and one between three drugs:

[["artesunate", "artemether", "COMB"], ["Nifedipine", "Labetalol", "Prazosin", "POS"]]

The paragraph and specific sentence are below. You should only extract relationships expressed in the specific sentence; the paragraph is provided for context.

In your output, return only the json array and no other text. If no drug combinations appear, return an empty array `[]`.

paragraph: Antimicrobial susceptibilities of exfoliative toxigenic and non-toxigenic Staphylococcus hyicus strains in Japan. Staphylococcus hyicus isolates (n=207), including 150 exfolitative toxigenic and 57 non-toxigenic strains, were examined for their susceptibility to 13 antimicrobial agents by using the dehydrated 96-well MIC panel system. The frequency of their resistance to penicillin and ampicillin was 76.8 % ( 159/207 ) , followed by erythromycin ( 56 % , 116/207 ) , trimethoprim-sulfamethoxazole ( 28.5 % , 59/207 ) , chloramphenicol ( 24.2 % , 50/207 ) , kanamycin ( 19.8 % , 41/207 ) , and doxycycline ( 1.4 % , 3/207 ) . Resistance to chloramphenicol and trimethoprim-sulfamethoxazole was significantly higher in toxigenic strains than non-toxigenic strains (p<0.01), whereas kanamycin and erythromycin resistance was significantly higher in non-toxigenic strains (p<0.01 and <0.05, respectively). Resistance to two or more antimicrobials was observed in 85.5% (177/207) of total strains, with a significantly higher occurrence in toxigenic strains (89.3%, 134/150 vs. 75.4%, 43/57; p<0.05).

sentence: The frequency of their resistance to penicillin and ampicillin was 76.8 % ( 159/207 ) , followed by erythromycin ( 56 % , 116/207 ) , trimethoprim-sulfamethoxazole ( 28.5 % , 59/207 ) , chloramphenicol ( 24.2 % , 50/207 ) , kanamycin ( 19.8 % , 41/207 ) , and doxycycline ( 1.4 % , 3/207 ) .
[]