Treatment of uncomplicated gonococcal infection with trimethoprim-sulfamethoxazole

What's left in the cupboard? Older antimicrobials for treating gonorrhoea

BACKGROUND

Neisseria gonorrhoeae has developed resistance to all antimicrobials used to treat gonorrhoea, with even ceftriaxone being undermined. It is therefore important to examine any potential to redeploy older antimicrobials routinely used for other infections to treat ceftriaxone-resistant gonococcal infections.

OBJECTIVES

We examined the susceptibility of N. gonorrhoeae to aztreonam, chloramphenicol, co-trimoxazole, fosfomycin, piperacillin/tazobactam and rifampicin.

METHODS

N. gonorrhoeae isolates (n = 94) were selected to include a range of antimicrobial susceptibilities: 58 were collected in the Gonococcal Resistance to Antimicrobials Surveillance Programme; 17 were clinical isolates referred to the PHE reference laboratory; and 19 were control strains. MICs were determined by agar dilution for the six study antimicrobials and for ceftriaxone and azithromycin as comparators.

RESULTS

There was correlation between piperacillin/tazobactam and ceftriaxone MICs, but all five isolates with high ceftriaxone MICs (>0.5 mg/L) were inhibited by piperacillin/tazobactam at 0.06-0.5 mg/L. Aztreonam MICs for ceftriaxone-resistant isolates exceeded those of ceftriaxone. Among non-β-lactams, fosfomycin and co-trimoxazole had low, tightly clustered MICs, suggesting widespread susceptibility, rifampicin split the collection into highly susceptible and highly resistant groups and chloramphenicol had a wide MIC distribution.

CONCLUSIONS

Although unsuitable for empirical use, piperacillin/tazobactam, fosfomycin, co-trimoxazole, rifampicin and, possibly, chloramphenicol could be considered for individual patients with ceftriaxone-resistant gonococcal infection once MICs are known. Wider surveillance of the susceptibility of N. gonorrhoeae to these agents is needed, along with clinical trials and the establishment of clinical breakpoints for N gonorrhoeae.

Asymptomatic sexually transmitted diseases: the case for screening

BACKGROUND

The United States has the highest prevalence of sexually transmitted diseases in the developed world. Control strategies should address the most frequent reasons why curable sexually transmitted diseases are not treated.

METHODS

We approached 1,631 persons ages 18-29 in various sites and offered them screening for gonorrhea and chlamydial infection and surveys regarding past genitourinary symptoms. For those with past symptoms we abstracted medical records or conducted additional interviews. From these data we estimated the total number of persons who had gonorrhea or chlamydial infections in the previous year, the proportion treated, and the primary reasons for nontreatment.

RESULTS

The prevalence of gonorrhea was 2.3% and that of chlamydial infection was 10.1%. We estimate that 45 and 77% of all cases of gonorrhea and chlamydial infection, respectively, were never symptomatic and that 86 and 95% of untreated cases of gonorrhea and chlamydial infection, respectively, were untreated because they were never symptomatic. The remaining 14 and 5% of untreated cases of gonorrhea and chlamydia, respectively, were not treated because persons did not receive medical care for symptoms.

CONCLUSIONS

The primary reason that gonorrhea and chlamydial infections are untreated is that infected persons never have symptoms. The most effective method to control these sexually transmitted diseases is routine screening at high-volume sites.

Treatment of gonorrhoea and susceptibility to antimicrobials of PPNG and non-PPNG strains in Jamaica

Of 1400 patients in Jamaica screened for uncomplicated gonorrhoea, 54% (753 patients) were culture positive. Of the 459 patients who complied with the terms of the study, 97% (211/218) of those treated with aqueous procaine penicillin G were cured compared with 94% (227/241) of those treated with ampicillin. Penicillinase producing Neisseria gonorrhoeae (PPNG) strains were identified for the first time during the study, and 10 patients infected with PPNG strains (two treated with penicillin, eight with ampicillin) contributed to the 21 treatment failures. The in vitro susceptibility of eight antimicrobial agents for 629 non-PPNG and 20 PPNG strains was estimated. Of the non-PPNG isolates, 8% had an MIC of 1 mg/l or more of penicillin, 11% were resistant to this concentration of ampicillin, 32% to tetracycline, and under 1% to the same concentration of cefuroxime and erythromycin. Fewer than 2% of the isolates were resistant to 2 mg/l or more thiamphenicol, and all isolates were susceptible to spectinomycin and trimethoprimsulphamethoxazole (at a ratio of 1:19). Significantly more strains from the 21 treatment failures were resistant to penicillin (52%) or ampicillin (62%) compared with 7% strains resistant to penicillin and 4% to ampicillin from the successfully treated group.

Single-dose antibiotic therapy for the treatment of uncomplicated anogenital gonorrhoea

Appropriate single-dose therapy will cure in excess of 95% of cases of uncomplicated anogenital gonorrhoea. Changes in the susceptibility of local isolates of Neisseria gonorrhoeae, particularly the emergence of beta-lactamase producing (and therefore penicillin-resistant) strains, have necessitated the modification of standard treatment regimens. Different patterns of antibiotic resistance have been documented in different regions of Australia and therapeutic regimens that are appropriate for use in different regions are recommended.

Penicillinase-producing Neisseria gonorrhoeae: epidemiology, antimicrobial susceptibility and plasmid types

Between 1976 and 1984 204 infections by penicillinase-producing Neisseria gonorrhoeae (PPNG) were seen in the Whitechapel Clinic. In 1984 PPNG were isolated from 4.7% of all patients attending with gonorrhoea. Three infections were homosexually acquired; 140 infections (68%) were acquired in the U.K. Strains that were tested were fully sensitive to spectinomycin (190), cefuroxime (177), kanamycin (170), amoxycillin combined with clavulanic acid (24) and rosoxacin (18). Of 135 strains 61% were resistant to co-trimoxazole, 69% of 169 to tetracycline (MIC greater than or equal to I mg/l) and 32% of 75 to streptomycin. Of 109 strains subjected to plasmid typing, 72(66%) were Asian strains. Of these, 55 (50% of the total) were without and 17 (16% of the total) possessed the 24.5 Mdal transfer plasmid; 27 (25%) were African strains without and 10 (9%) with the transfer plasmid. Of the Asian strains 10 were acquired in Africa. All four plasmid-containing strains are now endemic in the U.K. On the basis of the sensitivity tests, spectinomycin, cefuroxime and kanamycin should be effective in treatment, but not co-trimoxazole and tetracycline.