Chromosomal resistance of gonococci to antibiotics.

Abstract

SUMMARY Three hundred and twenty nine strains of non-penicillinase-producing Neisseria gonorrhoeae (non-PPNG) isolated from men and women were tested for their susceptibility to a range of antibiotics, and were also auxotyped and serogrouped. Nearly 6% (18) of 312 strains tested were resistant to 1 mg/l or more penicillin (compared with 4.4% of PPNG strains isolated in 1981). Many (198, 64%) strains showed intermediate resistance to penicillin (0.12-0.5 mg/l). Nearly 5% (15) of 312 strains tested were resistant to 0.5 mg/l or more cefuroxime, and there was a high degree of cross resistance between these two antibiotics. High levels of resistance to erythromycin and tetracycline were also found, and there was also appreciable cross resistance between these antibiotics and the ,B lactam drugs. Resistance to spectinomycin was rare, and there was no cross resistance between spectinomycin and other agents tested. Levels of resistance between -strains isolated from different anatomical sites did not differ, except that resistance to erythromycin was greater in rectal isolates. Four main auxotypes were detected. Strains requiring arginine, hypoxanthine, and uracil (AHU -) were more prevalent from the cervix. We have shown that there is an association between auxotype, serogroup, and level of sensitivity to penicillin, cefuroxime, and tetracycline.The epidemiology and treatment of infections caused by penicillinase producing strains of Neisseria gonorrhoeae (PPNG) have been major concerns since the first description of these strains in 1976.1 2 The prevalence of infections with PPNG strains is highest in Africa and the Far East. In the United Kingdom the increase in the prevalence of PPNG strains was rapid between 1980 and 1983, but now appears to have slowed.3 Our own experience with PPNG strains isolated from patients attending the Praed Street Clinic mirrors that seen nationally, and we saw a decline in prevalence of PPNG strains in 1985.4 Though the problem of PPNG strains has been more spectacular, resistance to antibiotics in non-PPNG strains has continued to grow, particularly in the Far East. In Thailand more than half the non-PPNG strains are resistant to 1 mg/I or more benzylpenicillin, and 21% are resistant to 0.5 mg/l or more cefuroxime~;5 Resistance to penicillin in non-PPNG strains results from chromosomal mutations at multiple loci, each producing small increments in resistance. Some loci are specific for penicillin resistance (pen A), others mediate resistance to a

Trends in susceptibility of Neisseria gonorrhoeae to ceftriaxone from 1985 through 1991

“…Decreased susceptibility to the expanded-spectrum cephalosporins such as cefoxitin and cefuroxime has also developed (12,18). In the present study, chromosomally mediated resistance to penicillin G and tetracycline and decreased susceptibility to cefoxitin were highly correlated with increased MICs of ceftriaxone.…”

“…Clinically significant chromosomal resistance to levels of penicillin G or tetracycline, attainable with single doses of penicillin G or with maximum dosages of tetracycline, has been recognized in the gonococcus since the early 1980s (6,18), and the genetic loci involved in resistance to these antibiotics are closely related (5,7,12). Decreased susceptibility to the expanded-spectrum cephalosporins such as cefoxitin and cefuroxime has also developed (12,18).…”

“…In the present study, chromosomally mediated resistance to penicillin G and tetracycline and decreased susceptibility to cefoxitin were highly correlated with increased MICs of ceftriaxone. Decreased susceptibility of N. gonorrhoeae to ceftriaxone appears due to chromosomally mediated alterations in outer membrane permeability and altered affinity of penicillin-binding proteins for ceftriaxone, as for penicillin G (2,5,12).…”

Antimicrobial susceptibilities and serotyping of Neisseria gonorrhoeae in southern Africa: influence of geographical source of infection

“…A ntimicrobial susceptibility testing In vitro susceptibilities of gonococcal isolates to penicillin (0-015-4-0 mg/l), ceftriaxone (0-001-1-0 mg/l), tetracycline (0 008-8-0 mg/l), spectinomycin mg/l), ciprofloxacin (0-001-1 0 mg/l) and azithromycin (0002-2-0 mg/l) were determined using an agar dilution technique described previously [9]. Briefly …”

Beta-lactamase plasmids and chromosomally mediated antibiotic resistance in pathogenic Neisseria species

“…The decrease in the susceptibility of Neisseria gonorrhoeae isolates to antimicrobial agents has been extensively documented over the past four decades (12,20,34,67,76).…”