Addressing antimicrobial resistance in the treatment of uncomplicated UTIs

Jairia Dela Cruz
02 Aug 2016
The susceptibility profile of causative bacteria and the potential collateral damage of treatments should be confirmed and considered when selecting appropriate antimicrobials in the management of acute uncomplicated cystitis (AUC) and pyelonephritis (AUP) for Asian patients, according to the UAA/AAUS* guidelines presented at the 14th Urological Association of Asia (UAA) Congress 2016 in Singapore.

AUC

Nitrofurantoin (100 mg BID for 5 to 7 days) is the first-choice treatment for AUC in countries where the drug is available, as follows: Singapore, China, and Russia. Other treatment alternatives are trimethoprim-sulfamethoxazole (TMP/SMZ; 1,600/800 mg BID for 3 days), fosfomycin trometamol (3 g for 1 day) or fosfomycin calcium (1 g TID for 2 days), cefaclor (250 mg TID for 7 days), cephalexin (250 mg QID for 7 days), and amoxicillin clavulanate (500/125 mg BID for 7 days), all of which are available in most Asian countries.

“The most important issue for uncomplicated urinary tract infections (UTIs) in Asia [however] is increasing fluoroquinolone resistance and extended-spectrum beta-lactamase (ESBL)-producing Gram-negative bacilli,” said Prof. Hiroshi Hayami from Kagoshima University Hospital.

In order to properly prescribe treatment, clinicians should identify the drug susceptibility of the strains, distinguishing between the coccus- and coli-forms of the uropathogen causing AUC, Hayami said. A way to do this is to perform a microscopic examination or flowcytometry.

For coli-form or unknown infections, the recommended first-line antimicrobials include fosfomycin, nitrofurantoin, TMP/SMZ, cephalexin, and amoxicillin clavulanate. Third-generation cephalosporins may also be used as an alternative.

Fluoroquinolones should be avoided for coli-form infections and indicated for those of coccus-form, particularly Staphylococcus saprophyticus. Another treatment option for coccus-form infections is amoxicillin clavulanate.

Pregnant women may be prescribed fosfomycin, nitrofurantoin, cephalexin, amoxicillin clavulanate as first-line agents for AUC, as well as third-generation cephalosporins as an alternative.

“In addition, urine culture is recommended for patients at high risk of high drug resistance,” Hayami said.

AUP

Mild and moderate AUP may be treated in the outpatient setting, whereas severe cases require hospitalisation, he said.

Outpatient treatment is given to patients who do not present with the following: shock, systemic inflammatory response syndrome symptoms, gastrointestinal symptoms, dehydration, and factors affecting immunity such as diabetes and anti-cancer therapy.

First-line treatment options for mild and moderate cases include the oral antimicrobials ciprofloxacin (500 mg BID or 1,000 mg QD for 7 to 10 days), levofloxacin (500 to 750 mg QD for 7 to 10 days), sitafloxacin (100 mg QD for 7 to 10 days), and moxifloxacin (400 mg QD for 5 to 7 days). For severe cases, parenteral treatment is recommended with levofloxacin (500 to 750 mg QD), pazufloxacin (500 to 1,000 mg BID), and ciprofloxacin (400 mg BID).

Cephalosporin agents may be used as an alternative: cefpodoxime proxetil (200 mg BID for 10 to 14 days), ceftibuten (400 mg QD for 10 days), ceftitoren pivoxil (200 mg TID for 14 days), and cefcapen pivoxil (100 to 150 mg TID for 14 days) for mild and moderate AUP; cefotaxime (2 g TID), ceftriaxone (1 to 2 g QD), ceftazidime (1 to 2 g TID), cefepime (1 to 2 g BID), and co-amoxiclav (1.5 g TID) for severe AUP.

After clinical improvement within 72 hours, oral treatment should be continued for a total duration of 10 to 14 days in patients with mild to moderate AUP, whereas parenteral therapy should be switched to oral therapy given for 10 to 14 days in patients with severe AUP, Hayami said.  

“If clinical improvement is negative [in severe AUP cases], it is necessary to switch to definitive parenteral therapy in accordance to the results of susceptibility testing,” he added.

Moreover, clinicians should investigate the urinary system and potential systemic diseases among hospitalised patients, with the consideration of surgical treatment, he said.

* Asian Association of UTI and STD

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