Increasing antimicrobial resistance among uropathogens: Is fosfomycin the answer?

Introduction: Urinary tract infection (UTI) is one of the most common infectious diseases in clinical practice. The choice of antibiotics for the treatment of UTI is limited by the rising rates of antibiotic resistance. There is an urgent need to discover new effective treatment solutions. Fosfomycin may be an interesting alternative to the currently used treatments of UTIs.

Materials And Methods: The study was conducted over 6 months period (January to June 2013) in Department of Microbiology, JNMCH, AMU, Aligarh. A total of 1840 urine samples were submitted. Culture and sensitivity was done as per standard microbiological procedures. Methicillin-resistant Staphylococcus aureus (MRSA), high-level aminoglycoside resistance (HLAR), extended spectrum beta-lactamases (ESBL), AmpC and metallo-beta-lactamases (MBL) production was detected.

Results: Culture was positive in 504 (27.4%) cases. Gram-negative etiology was identified in 390 (73%) cases. ESBL production was detected in 154 (37.1%) while 82 (21.6%) were Amp C. No, MBL was detected. Among Gram-positive bacteria, 68 (51.5%) were MRSA, while 4 (13.3%) were vancomycin resistant enterococci (VRE). HLAR was seen in 53.3% of enterococci. Fosfomycin was effective in 100% of MRSA, VRE, ESBL, HLAR, and overall, susceptibility to fosfomycin in AmpC producers was extremely high (99%). Norfloxacin and cotrimoxazole were not proved effective as only three isolates were sensitive to norfloxacin, while all Gram-negative isolates were resistant to cotrimoxazole. Pseudomonas species showed 65% and 75% susceptibility to colistin and polymixin B, respectively.

Conclusion: Fosfomycin has emerged as a promising option, especially in cases involving multi-drug-resistant pathogens in which previous antibiotics have failed to cure the infection.