Rheumatoid Arthritis is Caused by Asymptomatic Proteus Urinary Tract Infections

Urinary tract infections (UTI) are considered as one of the most common groups of infections in humans and affecting either the upper (kidneys--pyelonephritis) or the lower (bladder--cystitis) part of the urinary tract (Thomson and Armitage, 2010). The gastrointestinal tract is a reservoir from which uropathogens emerge. Reflecting this, Enterobacteriaceae are the most important cause of UTI in all population groups, accounting for more than 95% of all UTIs. Among these microbes, E. coli is by far the most common invader, causing some 90% of UTIs in outpatients and approximately 50% in hospitalized patients. Whilst, the frequency of P. mirabilis causing outpatient and inpatients UTIs were 3.2% and 12.7% respectively, these value were reversed to 26.6% and 9.3% when all strains of Proteus species were examined (Talkoff-Robin et al, 2008). In a most recent multicentre study involving nine Spanish hospitals, 784 women with uncomplicated cystitis were evaluated for the frequencies of isolated uropathogens and their susceptibility to antibiotics. Among the 650 pathogens isolated, the first group of the most frequent bacterial agents was Escherichia coli (79.2%) followed by Staphylococcus saprophyticus (4.4%), Proteus mirabilis (4.3%), Enterococcus faecalis (3.3%), and Klebsiella pneumoniae (2.3%) (Palou et al, 2011). In contrast to E. coli strains, it appears that all strains of P. mirabilis, regardless of isolate origin, are capable of infecting the urinary tract (Sosa et al, 2006). Proteus is particularly significant as a renal pathogen especially in causing upper UTI because of its propensity to promote struvite renal calculi (Ronald and Nicolle, 2007).