Relationship between biofilm formation and MRPA gene in uropathogenic Proteus mirabilis

Proteus bacteria are piliated, Gram-negative rods that belong to the Enterobacteriaceae family. Hauser defined them for the first time in 1885. The genus Proteus now contains five species: P. mirabilis, P. vulgaris, P. penneri, and P. myxofaciens. Proteus mirabilis is a primary pathogen of nosocomial and opportunistic urinary tract infections (UTI). It has a strong preference for the upper urinary system, where it can cause significant kidney injury P. mirabilis is the third most usually isolated pathogen causing urinary tract infections (after E. coli and Klebsiella pneumoniae). They are primarily ascending infections, which are more prevalent in patients with anatomical or physiological urinary tract abnormalities, as well as in catheterized patients or as a result of medical care errors , In Iraq, P. mirabilis was identified in 17.5% of UTI patients,In this study, 180 mid-stream urine non-repeated specimens were collected from urinary tract infections patients referring several hospitals in Baghdad, Iraq, for the purpose of isolating Proteus mirabilis. VITEK(R) compact system was employed for identifying these isolates. Antibiotic suceptibility was assayed using Kirby-Bauer method and the minimal inhibitory concentration (MIC) was performed for the most resisted antibiotic (cefotaxime). Biofilm forming capacity was evaluated by microtiter plate method. PCR technique was used to confirm the identification by detecting 16S rRNA gene. Also PCR was employed for the detection of mrpA gene. Furthermore, qRT-PCR was used to assess the impact of cefotaxim at ½MIC on the gene expression of mrpA. The present results revealed that 20 isolates were identified as P. mirabilis. Cefotaxime was resisted by 18 isolates; wherease, higest sensitivity was towards tetracycline (7 isolates). Variably (P <0.05), all of which formed moderate biofilm except one isolate developed a strong biofilm. Intriguingly, 22.22% of isolates resisted 2048 µg/mL. Markedly, cefotaxim at ½MIC lowered the intensity and downregulated the mrpA gene in all isolates (P <0.05).