Streptococcus pneumoniae as an agent of urinary tract infections – a laboratory experience from 2010 to 2014 and further characterization of strains

• Streptococcus pneumoniae can rarely be isolated from urine.
• In some cases infection is very likely in others rather doubtful.
• Most patients suffer from urinary tract abnormalities.
• S. pneumoniae strains isolated from urine differ from invasive isolates.
• Isolates belong to different serotypes.

Streptococcus pneumoniae is a rare cause of urinary tract infection. Between January 2010 and December 2014, 26 urine samples from 18 different patients contained S. pneumoniae at the Department for Infectious Diseases, University Hospital of Heidelberg. Patient age varied between three and 72 years. 13 patients were male and five were female. Past medical histories of 16 patients were available. Eight patients had a past medical history of renal transplant and four patients had other renal dysfunctions. Further analyses of the isolates revealed that the aspect of colonies is more resembling S. mitis than invasive isolates of S. pneumoniae. Optochin disk diameters tend to be 14 mm or smaller. Identification using MALDI-TOF or VITEK2 identification cards was accurate. Only 2 isolates showed a decreased susceptibility towards penicillin (MIC = 0.5 mg/L). Eight different serotypes were identified using a PCR approach as well Neufeld-Quellungs reaction.