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Gonococcal surveillance

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

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 that are currently routinely surveyed are penicillin, ceftriaxone, ciprofloxacin and spectinomycin, all of which are administered as single dose regimens and currently used in Australia to treat 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 remove 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 TRNG. Tetracyclines are however not a recommended therapy for gonorrhoea in Australia. Comparability of data is achieved by means of a standardised system of testing and a programme-specific quality assurance process. Because of the substantial geographic differences in susceptibility patterns in Australia, regional as well as aggregated data are presented.

Reporting period 1 July to 30 September 1999

The AGSP laboratories examined a total of 859 isolates in this quarter. About 40 per cent of this total was from New South Wales, 20 per cent each from Victoria and Queensland, 10% from the Northern Territory and Western Australia and 3% from South Australia. Isolates from other centres were few in number.

Penicillins

Figure 6 shows the proportions of gonococci fully sensitive (MIC ≤ 0.03 mg/L), less sensitive (MIC 0.06 - 0.5 mg/L), relatively resistant (MIC ≥ 1 mg/L) or penicillinase producing (PPNG) aggregated for Australia and by State and Territory. A high proportion of PPNG and relatively resistant strains fail to respond to treatment with penicillins (penicillin, amoxycillin, ampicillin) and early generation cephalosporins.

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Figure 6. Penicill in resistance of gonococcal isolates, 1 July to 30 September 1999, by region

FS Fully sensitive to penicillin, MIC ≤ 0.03 mg/L
LSLess sensitive to penicillin, MIC 0.06 - 0.5 mg/L
RR Relatively resistant to penicillin, MIC ≥ 1 mg/L
PPNG Penicillinase producing Neisseria gonorrhoeae

Twenty per cent of all isolates were penicillin resistant by one or more mechanisms. The penicillin-resistant isolates comprised about one-third of all isolates in New South Wales and 8-10% of gonococci in Queensland, Victoria, South Australia and Western Australia. In the Northern Territory, 3% of isolates were penicillin resistant.

PPNG were present in all States and Territories in this quarter with the exception of South Australia. The number of PPNG isolated across Australia (56) increased in this quarter compared to the corresponding period in 1998 (44). Half of all the PPNG were found in Sydney (28) and Perth had the highest proportion of PPNG (8%). Acquisition data on PPNG, where available, suggested overseas contacts in Indonesia, the Philippines, Thailand, China and Singapore as sources of PPNG. In Perth, most PPNG were also TRNG, and Indonesia was a common source of acquisition. In New South Wales and Victoria local transmission of PPNG was noted.

The number of gonococci resistant to the penicillins by chromosomal mechanisms (CMRNG) was double that of PPNG, with the 115 CMRNG representing about 14% of stains tested. In the corresponding quarter in 1998 the number (217) and proportion (26%) of CMRNG were twice that in this period. CMRNG were present in all centres except Tasmania and Western Australia. More than a quarter of New South Wales isolates were CMRNG, but in most other centres they represented less than 5% of gonococci.

Ceftriaxone and spectinomycin

All isolates in Australia were again susceptible to these injectable agents.

Quinolone antibiotics

The total number (152) and proportion (18%) of isolates with altered susceptibility to the quinolone group (QRNG) remained high. The QRNG isolates were distributed widely, being present in all centres except Tasmania and South Australia. They were however, particularly concentrated in New South Wales and Victoria. Forty-four isolates (29%) were QRNG in Victoria and 93 (26%) in New South Wales and together these accounted for 90% of all QRNG. Eighteen of the New South Wales and 5 of the Victorian QRNG exhibited high level resistance (MIC ciprofloxacin ≥ 1 mg/L) and MICs ranged up to 16mg/L. Most infections with this group of high level resistance QRNG were acquired overseas. However, the majority QRNG were in males, locally acquired and in the MIC range 0.06 - 0.5 mg/L. QRNG were also prominent in Brisbane where 7% of strains were of this type, again mainly in males and in the lower MIC range. Three QRNG were noted in Western Australia and one each in the Australian Capital Territory and Northern Territory.

In the corresponding period in 1998, the 37 QRNG represented about 4% of all isolates.

High level tetracycline resistance (TRNG)

The number (85) and proportion (10%) of TRNG detected also increased when comparisons were made with 1998 data (46 TRNG, 5.5%). TRNG were particularly prominent in Sydney, Melbourne, Brisbane and Perth with TRNG ranging between 8% and 11% of strains in those centres. One or two TRNG were present in Adelaide, the Northern Territory and Tasmania.

Reference

1. Anonymous. Management of sexually transmitted diseases. World Health Organization 1997; Document WHO/GPA/TEM94.1 Rev 1 p. 37.

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HIV and AIDS Surveillance

National surveillance for HIV disease is coordinated by the National Centre in HIV Epidemiology and Clinical Research (NCHECR), in collaboration with State and Territory health authorities and the Commonwealth of Australia. Cases of HIV infection are notified to the National HIV Database on the first occasion of diagnosis in Australia, by either the diagnosing laboratory (ACT, New South Wales, Tasmania, Victoria) or by a combination of laboratory and doctor sources (Northern Territory, Queensland, South Australia, Western Australia). Cases of AIDS are notified through the State and Territory health authorities to the National AIDS Registry. Diagnoses of both HIV infection and AIDS are notified with the person's date of birth and name code, to minimise duplicate notifications while maintaining confidentiality.

Tabulations of diagnoses of HIV infection and AIDS are based on data available three months after the end of the reporting interval indicated, to allow for reporting delay and to incorporate newly available information. More detailed information on diagnoses of HIV infection and AIDS is published in the quarterly Australian HIV Surveillance Report, and annually in HIV/AIDS and related diseases in Australia Annual Surveillance Report. The reports are available from the National Centre in HIV Epidemiology and Clinical Research, 376 Victoria Street, Darlinghurst NSW 2010. Telephone: (02) 9332 4648; Facsimile: (02) 9332 1837; http://www.med.unsw.edu.au/nchecr.

HIV and AIDS diagnoses and deaths following AIDS reported for 1 to 31 October 1999, as reported to 31 January 2000, are included in this issue of CDI (Tables 8 and 9).

Table 8. New diagnoses of HIV infection, new diagnoses of AIDS and deaths following AIDS occurring in the period 1 to 31 October 1999, by sex and State or Territory of diagnosis

		ACT	NSW	NT	Qld	SA	Tas	Vic	WA	Totals for Australia
										This period 1999	This period 1998	Year to date 1999	Year to date 1998
HIV diagnoses	Female	0	0	1	3	0	0	0	0	4	8	57	76
	Male	0	0	0	9	4	0	10	0	23	46	465	524
	Sex not reported	0	0	0	0	0	0	0	0	0	0	4	5
	Total1	0	0	1	12	4	0	10	0	27	54	526	605
AIDS diagnoses	Female	0	0	0	0	0	0	0	0	0	2	13	15
	Male	0	3	1	1	0	0	0	0	5	13	100	240
	Total1	0	3	1	1	0	0	0	0	5	15	113	255
AIDS deaths	Female	0	0	0	0	0	0	0	0	0	1	3	8
	Male	0	5	0	1	1	0	3	1	11	10	80	123
	Total1	0	5	0	1	1	0	3	1	11	11	84	131

1. Persons whose sex was reported as transgender are included in the totals.

Table 9.Cumulative diagnoses of HIV infection, AIDS and deaths following AIDS since the introduction of HIV antibody testing to 31 October 1999, by sex and State or Territory

		State or Territory								Australia
		ACT	NSW	NT	Qld	SA	Tas	Vic	WA
HIV diagnoses	Female	25	593	10	145	61	6	211	111	1,162
	Male	192	10,700	107	1,948	672	79	3,854	897	18,449
	Sex not reported	0	260	0	0	0	0	24	0	284
	Total1	217	11,572	117	2,100	733	85	4,102	1,011	19,937
AIDS diagnoses	Female	8	182	0	47	25	3	68	26	359
	Male	86	4,607	36	807	345	44	1,601	344	7,870
	Total1	94	4,801	36	856	370	47	1,676	372	8,252
AIDS deaths	Female	3	114	0	31	15	2	47	16	228
	Male	65	3,164	24	561	230	28	1,256	246	5,574
	Total1	68	3,286	24	594	245	30	1,309	263	5,819

1. Persons whose sex was reported as transgender are included in the totals.

This article was published in Communicable Diseases Intelligence Volume 24, No 3, 16 March 2000.