Resistance to antibiotics is a growing public health crisis, especially in countries with fragile health systems and in regions at war. One key limitation in most of these settings is a lack of clinical bacteriology laboratory capacity, which leaves medical providers without ways to accurately diagnose patient infections and to tailor antibiotic treatment accordingly. To help fill this critical gap, MSF and partners have developed the Mini-Lab—a small-scale, standalone lab that is easy to transport, set up and operate by staff after only a short training. Its six modules are stocked with everything needed to diagnose common bloodstream and urinary tract infections and to perform antibiotic sensitivity testing using methods adapted to extremely hot climates and remote settings. With Mini-Lab now being rolled out to selected MSF projects, here we highlight the background to its development and some of the research behind the bacteriological tests it incorporates.