Increasing resistance to quinolones is concerning
Antimicrobial resistance to quinolones is prevalent in many geographic locations in New Zealand, and includes both
Gram-negative and Gram-positive strains.1
Urinary tract infections: community prescribing impacts on resistance patterns
Acute uncomplicated cystitis is one of the most common indications for prescribing antibiotics in otherwise healthy
women.6 Antimicrobial resistance to uropathogens causing uncomplicated cystitis has increased over time.4
Uncomplicated cystitis and pyelonephritis is mainly caused by E. coli (75 to 95%), with occasional involvement
of Enterobacteriaceae, such as Proteus mirabilis and Klebsiella pneumoniae, and Staphylococcus
saprophyticus. Local antimicrobial susceptibility patterns of E. coli should be considered in empirical
While quinolones are an effective treatment for acute cystitis, the pattern of increasing antimicrobial resistance
threatens their long-term usefulness. The resistance level of urinary E. coli infections to quinolones is approaching
8% (Table 1).2 There is also concern about the association between quinolone use and increased rates of MRSA
Although local antimicrobial resistance rates are often skewed by data obtained from infections treated in the hospital
setting, which are more likely to be complicated infections, quinolone resistance is also linked to community prescribing
practices and therefore restrictive use is important.
Gonorrhoea – ciprofloxacin resistance greater than for penicillin
Penicillin was originally used to treat gonorrhoea but increasing penicillin resistance meant that empiric treatment
with ciprofloxacin became more favoured. Data collected by ESR in 2009 reveals that resistance levels of N. Gonorrhoeae to
quinolones is approaching 30%.2 This far exceeds the acceptable 5% resistance threshold for first-line therapy.
The rate of penicillin resistance for the same time period was approximately 12%.2 Ciprofloxacin resistance
is now more prevalent than penicillin resistance in most areas of New Zealand, but local variations do occur. Ceftriaxone
injection is advised for treating suspected gonorrhoea, unless susceptibility data is available.
See “Treatment of sexually
transmitted and other genital infections”, BPJ 20 (April, 2009).
: Antimicrobial resistance to urinary E. Coli
: data from hospital and community laboratories
(ESR, 2002, 2008, 2009)2