Gonococcal surveillance Australia: quarter 3, 2012

The Australian Gonococcal Surveillance Programme (AGSP) reference laboratories in the various states and territories report data on sensitivity to an agreed ‘core’ group of antimicrobial agents quarterly.

Page last updated: 08 June 2013

Monica M Lahra

The Prince of Wales Hospital, Randwick, NSW, 2031 for The Australian Gonococcal Surveillance Programme

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Introduction

The Australian Gonococcal Surveillance Programme (AGSP) reference laboratories in the various states and territories report data on sensitivity to an agreed ‘core’ group of antimicrobial agents quarterly. The antibiotics routinely surveyed are the penicillins, ceftriaxone, ciprofloxacin and spectinomycin which are current or potential agents used for the treatment of gonorrhoea. Azithromycin testing is now performed by all states and territories as it has a role as part of a dual therapy regimen in the treatment of gonorrhoea. When in vitro resistance to a recommended agent is demonstrated in 5% or more of isolates from a general population, it is usual to consider the removal of that agent from the list of recommended treatments.1 Additional data are also provided on other antibiotics from time to time. At present all laboratories also test isolates for the presence of high level (plasmid-mediated) resistance to the tetracyclines, known as tetracycline-resistant Neisseria gonorrhoeae (TRNG). Tetracyclines are however not a recommended therapy for gonorrhoea in Australia. These data are reported in the AGSP Annual Report. Comparability of data is achieved by means of a standardised system of testing and a programme-specific quality assurance process. Due to the substantial geographic differences in susceptibility patterns in Australia, regional as well as aggregated data are presented. Since quarter 2, 2012 these data have been presented quarterly in tabulated form, as well as in the AGSP Annual Report. Tables for quarters 1, 2 and 3 2012 have been included in this report to complete presentation of the AGSP quarterly data in this format for 2012.

Table 1: Gonococcal isolates showing decreased susceptibility to ceftriaxone and resistance to ciprofloxacin, azithromycin and penicillin, Australia, 1 January to 30 March 2012, by state or territory

State or Territory Number of isolates tested Decreased susceptibility Resistance
Ceftriaxone Ciprofloxacin Azithromycin Penicillin
n % n % n % n %
Australian Capital Territory 9 0 0.0 4 44.4 0 0.0 3 33.3
New South Wales 421 16 3.8 115 27.3 0 0.0 105 24.9
Northern Territory 82 0 0.0 0 0.0 0 0.0 1 1.2
Queensland 174 8 4.6 26 14.9 2 1.1 48 27.6
South Australia 44 0 0.0 7 15.9 0 0.0 7 15.9
Tasmania 4 0 0.0 1 25.0 0 0.0 3 75.0
Victoria 355 21 5.9 149 42.0 108 30.4 202 56.9
Western Australia 119 1 0.8 30 25.2 1 0.8 26 21.8
Australia 1208 46 3.8 332 27.5 111 9.2 395 32.7

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Table 2: Gonococcal isolates showing decreased susceptibility to ceftriaxone and resistance to ciprofloxacin, azithromycin and penicillin, Australia, 1 April to 30 June 2012, by state or territory

State or territory Number of isolates tested Decreased susceptibility Resistance
Ceftriaxone Ciprofloxacin Azithromycin Penicillin
n % n % n % n %
Australian Capital Territory 15 1 6.7 1 6.7 0 0.0 0 0.0
New South Wales 442 20 4.5 146 33.0 3 0.7 126 28.5
Northern Territory 47 0 0.0 4 8.5 0 0.0 4 8.5
Queensland 159 2 1.3 25 15.7 3 1.9 42 26.4
South Australia 41 1 2.4 16 39.0 0 0.0 19 46.3
Tasmania 4 0 0.0 2 50.0 0 0.0 2 50.0
Victoria 279 36 12.9 120 43.0 7 2.5 146 52.3
Western Australia 136 3 2.2 34 25.0 0 0.0 37 27.2
Australia 1,123 63 5.6 348 31.0 13 1.2 376 33.5

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Table 3: Gonococcal isolates showing decreased susceptibility to ceftriaxone and resistance to ciprofloxacin, azithromycin and penicillin, Australia, 1 July to 30 September 2012, by state or territory

State or territory Number of isolates tested Decreased susceptibility Resistance
Ceftriaxone Ciprofloxacin Azithromycin Penicillin
n % n % n % n %
Australian Capital Territory 15 1 6.7 1 6.7 0 0.0 0 0.0
New South Wales 442 20 4.5 146 33.0 3 0.7 126 28.5
Northern Territory 47 0 0.0 4 8.5 0 0.0 4 8.5
Queensland 159 2 1.3 25 15.7 3 1.9 42 26.4
South Australia 41 1 2.4 16 39.0 0 0.0 19 46.3
Tasmania 4 0 0.0 2 50.0 0 0.0 2 50.0
Victoria 279 36 12.9 120 43.0 7 2.5 146 52.3
Western Australia 136 3 2.2 34 25.0 0 0.0 37 27.2
Australia 1123 63 5.6 348 31.0 13 1.2 376 33.5

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Comments and Notes

Penicillin resistant N. gonorrhoeae are defined as those isolates with an minimum inhibitory concentration (MIC) to penicillin equal to or greater than 1.0 mg/L. Total penicillin resistance includes penicillinase producing N. gonorrhoea (PPNG) and chromosomally mediated resistance to penicillin (CMRP).

Quinolone resistant N. gonorrhoeae are defined as those isolates with an MIC to ciprofloxacin equal to or greater than 0.06 mg/L, and azithromycin resistance as those isolates with an MIC to azithromycin equal to or greater than 1.0 mg/L. In the Northern Territory, the number of isolates for which results were available in the 3rd quarter 2012 was lower than in the previous two quarters as data from Alice Springs was not available. Penicillin and ciprofloxacin resistance increased to 8.5% in this quarter in the 47 N. gonorrhoeae isolates tested in the Northern Territory.

Regarding ceftriaxone, isolates with MIC values in the range 0.06-0.125 mg/L are reported as having decreased susceptibility. There has not been an isolate reported in Australia with an MIC >0.125mgL. In Figure 1 the AGSP data for 2011 Quarters 1, 2 and 3, and for the same period in 2012 is presented by ceftriaxone MIC value to enable monitoring of the shift in MIC values in N. gonorrhoeae isolates over time, in addition to reporting the proportion in the category of decreased susceptibility. A decrease in proportion of isolates with a ceftriaxone MIC value of = 0.008mgL is evident in 2012 compared with 2011, with increases in the higher MIC values demonstrating a right shift over these periods which will continue to be monitored.

Figure 1: Distribution of ceftriaxone MIC values in gonococcal isolates tested in the AGSP, Quarters 1, 2 and 3: January to September, 2011 and 2012

bar chart. Described above

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References

  1. Management of sexually transmitted diseases. World Health Organization [online] 1997. [Revised 1997:p.37].

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