I need some help consolidating columns in R

I have ~130 columns, some of which have a similar name. For example, I have ~25 columns called "pathogen".
However, after importing my datasheet into R, these colums are now listed as follows : pathogen..1, pathogen...2, etc. Because of how R renamed these columns, I'm not sure how to proceed.

I need to consolidate all my columns with the same/similar name, so that I have only 1 column called "pathogen". I also need this consolidated column to include the sums of all the consolidated columns called "pathogen".

here an example of my input

```html
sample  Unidentified…1  Unidentified…2  Pathogen..1 Pathogen…2
1              5                 3             6            8
2              7                 2             1            0
3              8                 4             2            9
4              9                 6             4            0
5              0                 7             5            1
```

Here is my desired output

```html
Sample  Unidentified    Pathogen
1            8           14
2            9            1
3            12           11
4            15           4
5            7            6
```

Any help would be really appreciated.