Antimicrobial susceptibility of Neisseria gonorrhoeae isolates from a military population in San Diego

Neisseria gonorrhoeae isolates were studied to determine their patterns of antimicrobial susceptibility and possible chemotherapeutic implications. Of 370 consecutive isolates, 32 (8.7%) were penicillinase-producing N. gonorrhoeae (PPNG). The remaining 338 were subjected to disk-diffusion tests, and those apparently resistant to penicillin, tetracycline, or spectinomycin were tested by an agar-dilution method. The dilution test showed that 5.4% (20/370) were penicillin-resistant, non-PPNG strains, of which 100%, 90%, and 45% were also resistant to tetracycline, cefoxitin, and erythromycin, respectively. No resistance to spectinomycin or ceftriaxone was demonstrated, although there was an association between minimum inhibitor concentrations (MICs) of penicillin of greater than or equal to 1.0 microgram/ml and increased MICs of ceftriaxone. The overall incidence of penicillin resistant isolates, including PPNG, was 14.1% (52/370). Of the 20 penicillin-resistant, non-PPNG strains, all were also resistant to tetracycline, and another 21 exhibited tetracycline resistance but were sensitive to penicillin. The in-vitro data suggested that: (1) neither penicillin, tetracycline, nor cefoxitin were acceptable drugs for routine treatment of gonorrhea in our population during the study period; (2) spectinomycin and ceftriaxone continue to demonstrate adequate in-vitro activity against N. gonorrhoeae despite increasing in-vitro resistance to penicillin; and (3) non-plasmid-mediated resistance to penicillin may predict future resistance to ceftriaxone.     

Antimicrobial susceptibility of Neisseria gonorrhoeae isolated in Durban, South Africa.

One hundred and forty clinical isolates of Neisseria gonorrhoeae were screened for production of penicillinase by the intralactam strip method and chromogenic cephalosporin test. Minimum inhibitory concentrations (MICs) of penicillin, ampicillin, tetracycline, cefoxitin, cefuroxime, cefotaxime, sulphamethoxazole-trimethoprim (ratio 19/1), and spectinomycin, were measured for 100 strains by the agar dilution method. Seven (5%) of the 140 isolates were identified as penicillinase producing N gonorrhoeae (PPNG). The MICs of penicillin for the seven PPNG strains ranged from 0 X 25 mg/1 to 2 mg/1. Of the 93 non-PPNG strains, 80 (86%) were fully susceptible to penicillin with MICs ranging from 0 X 0037 mg/1 to 0 X 06 mg/1 and 13 (14%) were of intermediate penicillin resistance with MICs greater than or equal to 0 X 125 mg/1. Of the 100 isolates tested, 86% were fully susceptible to tetracycline with MICs of less than 1 mg/1. No spectinomycin resistant strains were encountered in this study. All gonococcal strains were susceptible to the cephalosporins tested as well as to sulphamethoxazole-trimethoprim.     

Antimicrobial susceptibility of Neisseria gonorrhoeae in Harare, Zimbabwe. Relationship to serogroup

The authors investigated one hundred fifty-four isolates of Neisseria gonorrhoeae obtained from men, women, and infants in Harare, Zimbabwe, for in vitro susceptibility to various antibiotics and for reactivity with serogrouping antisera. The authors found sixty-four (42%) isolates to be WI serogroup and 90 (58%) to be WII/III. One hundred three isolates were penicillinase-producing N. gonorrhoeae (PPNG); although all of these showed resistance to penicillin, 14 isolates had an MIC to penicillin of less than 10 mg/L. All of these 14 isolates were WI serogroup. Twenty-seven of the 51 non-PPNG showed in vitro resistance to penicillin (MIC greater than 1.25 mg/L). All but one of these chromosomally resistant isolates were WII/III serogroup. With cefuroxime, tetracycline, and erythromycin, 10-15% of isolates had MICs greater than accepted breakpoints. Most isolates were susceptible to thiamphenicol, and all were susceptible to ciprofloxacin, kanamycin, and spectinomycin. The authors noted that WI isolates, whether PPNG or not, were consistently more susceptible to antibiotics than WII/III isolates. Only with kanamycin and spectinomycin were the MICs of the two serogroups similar.     

Antimicrobial susceptibility of Neisseria gonorrhoeae isolated in Durban, South Africa

One hundred and forty clinical isolates of Neisseria gonorrhoeae were screened for production of penicillinase by the intralactam strip method and chromogenic cephalosporin test. Minimum inhibitory concentrations (MICs) of penicillin, ampicillin, tetracycline, cefoxitin, cefuroxime, cefotaxime, sulphamethoxazole-trimethoprim (ratio 19/1), and spectinomycin, were measured for 100 strains by the agar dilution method. Seven (5%) of the 140 isolates were identified as penicillinase producing N gonorrhoeae (PPNG). The MICs of penicillin for the seven PPNG strains ranged from 0 X 25 mg/1 to 2 mg/1. Of the 93 non-PPNG strains, 80 (86%) were fully susceptible to penicillin with MICs ranging from 0 X 0037 mg/1 to 0 X 06 mg/1 and 13 (14%) were of intermediate penicillin resistance with MICs greater than or equal to 0 X 125 mg/1. Of the 100 isolates tested, 86% were fully susceptible to tetracycline with MICs of less than 1 mg/1. No spectinomycin resistant strains were encountered in this study. All gonococcal strains were susceptible to the cephalosporins tested as well as to sulphamethoxazole-trimethoprim.     

Antibiotic susceptibility in relation to serogroup and auxotype of Neisseria gonorrhoeae isolates from Gabon

We tested 75 beta-lactamase-positive (penicillinase-producing Neisseria gonorrhoeae; PPNG) and 147 beta-lactamase negative (non-PPNG) strains of N. gonorrhoeae obtained during a two-year period in Franceville, a semirural community in southeastern Gabon, for susceptibility to antimicrobial agents, auxotype, and serotype. The most common auxotypes were the nonrequiring and proline-requiring strains. Of the non-PPNG strains tested, 37% belonged to serogroup WI, 48% to serogroup WII, and 15% could not be grouped with commercially available antisera. Except for four strains that belonged to serogroup WII, the PPNG strains were classified as serogroup WI or ungroupable. We determined the concentrations at which 90% of strains were inhibited (MIC90) for spectinomycin (32 mg/liter for both PPNG and non-PPNG), kanamycin (32 mg/liter for both PPNG and non-PPNG), tetracycline (2 mg/liter for non-PPNG, 1 mg/liter for PPNG), cefotaxime (0.03 mg/liter for non-PPNG, 0.008 mg/liter for PPNG), and penicillin (1 mg/liter for non-PPNG, greater than 32 mg/liter for PPNG). A MIC of greater than or equal to 2 mg of tetracycline/liter was noted for 17% of the strains. Strains belonging to serogroup WII were more resistant to tetracycline and cefotaxime than other strains. Proline-requiring strains were less susceptible to tetracycline, cefotaxime, and spectinomycin than the nonrequiring strains. The decreased sensitivity to penicillin (non-PPNG strains) and tetracycline was determined by proline-requiring strains belonging to serogroup WII.     

Inhibition of Neisseria gonorrhoeae isolates by Martin-Lewis medium. Epidemiology, susceptibility profile, and plasma analysis.

A study was undertaken on the premise that if an increase of 1 microgram/ml in the concentration of vancomycin in Martin-Lewis medium (MLM) could improve inhibition of Gram-positive cocci, then a concomitant increase in the inhibition of gonococci could also occur. Isolates of Neisseria gonorrhoeae that failed to grow on MLM accounted for 18-5% of all positive culture results for gonorrhoea. The incidence of isolates susceptible to vancomycin was 14% and of those susceptible to trimethoprim 2.4%; one isolate was susceptible to both vancomycin and trimethoprim. The antibiotic-susceptible isolates were more frequently isolated from asymptomatic white men. Plasmid analysis showed that the 2.4-megadalton cryptic plasmic was absent in the vancomycin-susceptible isolates. The large proportion of isolates failing to grow on selective MLM has important clinical implications for the diagnosis of gonorrhea.     

Antimicrobial susceptibility and biochemical patterns of Neisseria gonorrhoeae strains in Vejle area, Denmark

Background  Strains of Neisseria gonorrhoeae resistant to penicillin and ciprofloxacin have been isolated worldwide. Increasing number of N. gonorrhoeae that lack the enzyme proline aminopeptidase (proA-negative N. gonorrhoeae ) have been detected in many countries all over the world.
Objectives  This study aims to assess the resistance profiles of N. gonorrhoeae isolates sent to the Department of Clinical Microbiology in Vejle, Denmark, between 2003 and 2007, and to analyse their biochemical patterns.
Methods  Sixty-two strains of N. gonorrhoeae were retrospectively analysed for their susceptibility to penicillin, ciprofloxacin and ceftriaxone. The identification of isolated strains was confirmed using both biochemical and immunological tests.
Results  Twenty-one (33.9%) N. gonorrhoeae isolates were resistant to penicillin and 30 (48.4%) were resistant to ciprofloxacin. All strains were susceptible to ceftriaxone. Fifty-six (90.3%) N. gonorrhoeae strains showed API NH biochemical code 10 010 (produced acid from glucose and proline aminopeptidase). Six strains showed code 10 000 that lack the enzyme proline aminopeptidase (proA-negative N. gonorrhoeae ).
Conclusions  Ceftriaxone should be used as the first-line treatment of gonorrhoea in Vejle community area, Denmark, both for infections with proA-producing and proA-negative N. gonorrhoeae isolates, which circulate in the region.     

Inhibition of Neisseria gonorrhoeae isolates by Martin-Lewis medium. Epidemiology, susceptibility profile, and plasma analysis

A study was undertaken on the premise that if an increase of 1 microgram/ml in the concentration of vancomycin in Martin-Lewis medium (MLM) could improve inhibition of Gram-positive cocci, then a concomitant increase in the inhibition of gonococci could also occur. Isolates of Neisseria gonorrhoeae that failed to grow on MLM accounted for 18-5% of all positive culture results for gonorrhoea. The incidence of isolates susceptible to vancomycin was 14% and of those susceptible to trimethoprim 2.4%; one isolate was susceptible to both vancomycin and trimethoprim. The antibiotic-susceptible isolates were more frequently isolated from asymptomatic white men. Plasmid analysis showed that the 2.4-megadalton cryptic plasmic was absent in the vancomycin-susceptible isolates. The large proportion of isolates failing to grow on selective MLM has important clinical implications for the diagnosis of gonorrhea.     

Antimicrobial susceptibility testing, auxotyping, and serotyping of Neisseria gonorrhoeae strains isolated in India

Sixty-four Neisseria gonorrhoeae strains isolated from patients attending sexually transmitted disease clinics at Pune and Delhi between January 2007 and June 2008, were subjected to antimicrobial susceptibility testing, auxotyping, and serotyping. We observed 6 antibiotic resistance patterns, 6 auxotypes, 3 serogroups, and 17 serovars. The combination of auxotyping and serotyping is a potential useful method for typing N. gonorrhoeae as a result of high discriminatory index, rapidity, ease, and relatively lower cost.     

Comparison of Neisseria gonorrhoeae isolates from homosexual and heterosexual men.

The gene locus known as mtr confers resistance to hydrophobic dyes, detergents, and antibiotics. It has been suggested previously that the host environment is important in the selection of gonococcal strains with this outer membrane phenotype, and thus that strains with mtr gene loci should predominate in environments high in hydrophobic molecules. Furthermore, resistance to hydrophobic molecules has been related to a sevenfold increase in a minor outer membrane protein. To test these suggestions the outer membrane phenotypes of 61 strains of Neisseria gonorrhoeae were identified using 27 rectal isolates from homosexual men and 34 urethral isolates from heterosexual men who were matched for age. The cell envelope phenotype of each strain was identified on the basis of resistance to various hydrophobic compounds. The results were compared with the protein profiles of these strains on sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE); no significant correlation was found.     

Characterisation of PPNG and non-PPNG Neisseria gonorrhoeae isolates from Singapore.

OBJECTIVE--To characterise Neisseria gonorrhoeae isolates from Singapore. DESIGN--Characterisation of Neisseria gonorrhoeae isolates by auxotyping, serological analysis and plasmid profile analysis. SPECIMENS--Sixty randomly collected isolates from 41 symptomatic, untreated males and 19 female prostitutes were studied. RESULTS--Auxotyping of 25 PPNG and 35 non-PPNG strains showed that the Pro-auxotype was prevalent among both PPNG (56%) and non-PPNG (42.5%) strains. Prototrophic strains comprised 28% of PPNG and 32.5% of non-PPNG strains respectively. Serovar analysis showed that with the exception of seven serogroup WI strains, the majority belonged to serogroup WII/III. Serovar Aedih was predominant among both serogroup WI PPNG (80%) and non-PPNG (100%) strains. Serogroup WII/III PPNG strains were represented by nine serovars with the predominant serovars being Bacjk (28%) and Bcgjk (16%). Eleven serovars were identified in the WII/III non-PPNG strains and the major serovars were Bajk (20%), Bacjk (17%), Back (11.4%) and Beghjk (11.4%). Analysis of the 25 PPNG strains showed that 16 of them carried the 4.4 MDa (Asian type) resistance plasmid and nine strains harboured the 4.4 MDa plasmid in conjunction with the 24.5 MDa transfer plasmid. The cryptic plasmid of 2.6 MDa was present in 27 of the 35 non-PPNG strains. Five of the non-PPNG strains harbouring the cryptic plasmid also contained the 24.5 MDa transfer plasmid. The plasmid combination of 2.6 + 7.8 + 24.5 MDa was detected in three non-PPNG strains. CONCLUSION--The combination of epidemiological methods used in this study indicated the heterogeneity of N gonorrhoeae strains in Singapore. A total of 16 different combinations of auxotype, plasmid profile and serovar were seen in the 25 PPNG strains compared with 24 such combinations in the 35 non-PPNG strains. Such sensitive differentiation would otherwise not be possible using either auxotype-serovar (A/S) or auxotype-plasmid analysis.     

Plasmid profile, serogrouping, and auxotyping of Neisseria gonorrhoeae isolates from Africa.

The plasmid patterns of 90 isolates of Neisseria gonorrhoeae (including 39 penicillinase-producing strains) originating from various countries in Africa were determined. Serogrouping by coagglutination and auxotyping were used to characterise the isolates. The 4.4-megadalton plasmid was present in seven isolates out of 39 penicillinase-producing strains, two of which occurred with a conjugative 24.5-megadalton plasmid. The African strains were predominantly serogroup WI and wild type. Arginine-dependent isolates were as common as proline-dependent types.     

2008年中国淋球菌临床分离株耐药性的流行病学研究

目的 通过对2008年淋球菌耐药监测结果进行分析,了解我国不同地区淋球菌耐药株的流行现状.方法 淋球菌株来自2008年全国淋球菌耐药监测点符合要求的951例淋病患者,其中江苏156例、浙江71例、福建102例、广东207例,广西77例、海南43例、新疆45例、陕西72例、四川80例、重庆44例、天津54例.通过纸片酸度定量法测定β-内酰胺酶,琼脂稀释法测定大观霉素、环丙沙星、头孢曲松钠、四环素对淋球菌的最小抑菌浓度(MIC).结果 大观霉素有2株耐药(0.21%),头孢曲松451株中度敏感(47.42%),质粒介导的高度耐四环素淋球菌(TRNG)487株(51.21%),产青霉素酶淋球菌(PPNG)332株(34.91%),环丙沙星928株耐药(97.58%).淋球菌对多种抗菌药物敏感性间的等级相关分析显示,TRNG阳性率与PPNG阳性率呈正相关(r=0.20,P<0.01),淋球菌对头孢曲松的敏感性与PPNG阳性率负相关r=-0.09,P<0.01),而淋球菌对头孢曲松的敏感性与对环丙沙星的敏感性及TRNG阳性率、淋球菌对环丙沙星的敏感性与PPNG阳性率及TRNG阳性率间没有相关性.卡方分析显示,各省收集的淋球菌对头孢曲松的中敏率之间相差比较大,广西、海南、新疆、陕西四省的中敏率(分别为87.01%、69.77%、82.22%、86.11%)高于总体水平(47.42%);陕西省有2株淋球菌对大观霉素耐药;各省收集的淋球菌对环丙沙星的耐药率较一致(86.11%～100%);广东省收集的淋球菌中TRNG的阳性率(68.60%)明显高于总体水平(51.21%);四川省、浙江省收集的淋球菌中PPNG的阳性率(分别为63.75%和54.93%)明显高于总体水平(34.91%)(P<0.05).结论 不同地区的淋球菌对抗生素的耐药性有明显的差别,其中陕西省收集的淋球菌对首选药物中头孢曲松的中度敏感率及对大观霉素的耐药率较高,应引起重视.

Abstract：

Objective To study the current status of antimicrobial resistance of clinical Neisseria gonorrhoeae isolates in China by analyzing the surveillance results in 2008.Methods N. gonorrhoeae strains were collected from 951 eligible patients at national monitoring sites for resistance of N. gonorrheae,including 156 patients from Jiangsu province,71 from Zhejiang province,102 from Fujian province,207 from Guangdong province,77 from Guangxi province,43 from Hainan province,80 from Sichuan province,44 from Chongqing,45 from Xinjiang Uygur Autonomous Region,72 from Shaanxi province,and 54 from Tianjin.The production of β-lactamase was detected by paper acidometric testing,and minimum inhibitory concentrations(MICs)were determined by agar dilution method for spectinomycin,ciprofloxacin,cefiriaxone,tetracycline,respectively.Results Among the 951 N. gonorrhoeae isolates,2(0.21%)were resistant to spectinomycin,451(47.42%)showed reduced sensitivity to ceflriaxone,928(97.58%)were resistant to ciprofloxacin.Penicillinase-producing N.gonorrhoeae (PPNG) and plasmid mediated tetracycline-resistant N. gonorrhoeae (TRNG) accounted for 34.91%(332/951)and 51.21%(487/951) of these isolates respectively.Kendall rank correlation analysis showed that there was a positive correlation between the positivity rate of TRNG and PPNG(r=0.20,P<0.01),but a negative correlation between the susceptibility to cefiriaxone in N.gonorrhoeae and positivity rate of PPNG(r=-0.09,P<0.01).No correlation was observed between the susceptibility to cefiriaxone and susceptibility to ciprofloxacin or the positivity rate of TRNG,or between the susceptibility to ciprofloxacin and positivity rate of PPNG or TRNG.Chi-square analysis showed a marked increase in the percentage of N.gonorrhoeae isolates with reduced susceptibility to ceftriaxone in Guangxi province,Hainan province,Xinjiang Uygur Autonomous Region and Shaanxi province,the percentage of N.gonorrhoeae isolates with resisitance to spectinomycin in Shaanxi province,prevelance of TRNG in Guangdong province,and prevelance of PPNG in Sichuan and Zhejiang provinces compared with the average level (all P<0.05).Conclusions Thero is a significant diffefence in antimicrobial susceptibility of N.gonorrhoeae from difierent areas of China.A significant elevation is observed in the percentage of N.gonorrhoeae with reduced susceptibihty to cefifiaxone and resistance to spectinomycin in Shaanxi province.to which close attention should be paid.     

Antimicrobial susceptibility of Neisseria gonorrhoeae strains isolated in Guangzhou, China, 1996-2001

OBJECTIVE: To investigate the in vitro antimicrobial susceptibility and resistant trends of Neisseria gonorrhoeae strains isolated in Guangzhou, from 1996 to 2001. METHODS: The agar dilution method was used to determine the minimum inhibitory concentrations (MICs) to four antimicrobials, penicillin G, ciprofloxacin, ceftriaxone, and spectinomycin. The resistance of all strains to four antibiotics was interpreted according to criteria used in the project of surveillance of gonococcal antibiotic susceptibility in the WHO Western Pacific Region. Penicillinase producing N gonorrhoeae (PPNG) was analysed by the paper acidometric method. RESULTS: 793 consecutive N gonorrhoeae isolates collected in Guangzhou were studied from 1996 to 2001. A total of 55 strains of PPNG were identified and the prevalence rapidly spread from 2% to 21.8%. Of the four antibiotics examined, ceftriaxone and spectinomycin appeared to be the most effective agents although two spectinomycin resistant strains were isolated in 1996. Their MIC(50), MIC(90), and geometric mean MIC (MICmean) were all between the sensitive ranges of the interpretative criteria and remained stable over the years. However, resistance increased continuously to penicillin G and dramatically to ciprofloxacin. In 1996-2001, MIC(50), MIC(90), and MICmean of penicillin G increased from 1 micro g/ml to 2 micro g/ml, 4 micro g/ml to 32 micro g/ml, and 0.68 micro g/ml to 2.35 micro g/ml, respectively; those of ciprofloxacin steeply increased from 0.12 micro g/ml to 4 micro g/ml, 2 micro g/ml to 32 micro g/ml, and 0.14 micro g/ml to 2.62 micro g/ml in 1996-9, respectively, and then declined slightly in 2000-1. The prevalence of resistant isolates spread from 57.2% to 81.8% for penicillin G and from 17.6% to 72.7% for ciprofloxacin over the 6 years. CONCLUSION: Resistance to penicillin and ciprofloxacin increased greatly during 1996-2001. Ceftriaxone and spectinomycin should be used as the first line agents in treating gonorrhoea. It is of great importance to continuously survey the susceptibilities of N gonorrhoeae to antibiotics in controlling the spread of gonococcal infections.