Mutation patterns in gyrA and parC genes of ciprofloxacin resistant isolates of Neisseria gonorrhoeae from India

AIM: To analyse mutations in the gyrA and parC genes leading to possible increase in ciprofloxacin resistance (high MIC values for ciprofloxacin) in clinical isolates of Neisseria gonorrhoeae in Delhi, India. METHOD: MIC of ciprofloxacin for 63 clinical isolates of N gonorrhoeae were examined by the Etest method. Subsequently, gyrA and parC genes of these isolates were amplified and sequenced for possible mutations. RESULTS: Out of the 63 clinical isolates tested, only five (8%) isolates were found to be susceptible to ciprofloxacin (MIC <0.06 micro g/ml). DNA sequence analysis of the gyrA and the parC genes of all these isolates (n = 63) revealed that all isolates which were not susceptible to ciprofloxacin (n=58) had mutation(s) in gyrA and parC genes. 12 isolates (19%) exhibited high resistance with an MIC for ciprofloxacin of 32 micro g/ml. Two out of these 12 isolates (UD62 and UD63), harboured triple mutations (Ser-91 to Phe, Asp-95 to Asn and Val-120 to Leu) in the gyrA gene. The third mutation of Val-120 to Leu, lies downstream of the quinolone resistance determining region (QRDR) of the gyrA and has not been described before in gonococcus. In addition, both these isolates had a Phe-100 to Tyr substitution in the parC, a hitherto unknown mutation. CONCLUSIONS: Emergence of ciprofloxacin resistance with high levels of MIC values (up to 32 micro g/ml) in India is alarming. Double and triple mutations in gyrA alone or together in gyrA and parC could be responsible for such a high resistance.     

High occurrence of simultaneous mutations in target enzymes and MtrRCDE efflux system in quinolone-resistant Neisseria gonorrhoeae

BACKGROUND: Emergence of multidrug-resistant Neisseria gonorrhoeae resulting from new genetic mutations is a serious threat to controlling gonorrhea. GOAL: To determine 1) antimicrobial susceptibilities and the corresponding genetic mutations and 2) the role of MtrRCDE efflux system in gonococcal resistance to fluoroquinolones. STUDY DESIGN: Antimicrobial susceptibility testing and sequence analysis of gyrA, parC, and mtrR loci of 131 N. gonorrhoeae isolates from Japan. RESULTS: The proportion of N. gonorrhoeae strains resistant and intermediate-resistant to antimicrobials was 25.2% and 48.9% for ciprofloxacin, 25.2% and 30.5% for ofloxacin, 12.2% and 53.4% for penicillin; and 17.6% and 51.1% for tetracycline, respectively. Strains were categorized into 22 mutation profiles, with GyrA-S91F/ParC-D86N/MtrR-G45D being the most predominant profile. The frequency of mutation in gyrA, parC, mtrR, and the mtrR promoter was 71%, 47.3%, 77.1%, and 23.7%, respectively. Seventy-one percent of strains carried mutations in both gyrA and mtrR. CONCLUSION: This study reports simultaneous mutations in fluoroquinolone target enzymes and the MtrRCDE efflux system as a fluoroquinolone-resistant mechanism in N. gonorrhoeae.     

Molecular characterization of ciprofloxacin resistance of gonococcal strains in Spain

BACKGROUND: Over the past several years, the emergence of gonococcal isolates with intermediate or full resistance to fluoroquinolones has become a significant concern in several countries, including Spain. GOAL: The goal was to determine the occurrence of ciprofloxacin resistance among Neisseria gonorrhoeae strains in Spain during 2000 to 2001 and determine the frequency and patterns of mutations at gyrA, gyrB, and parC genes in these isolates. STUDY DESIGN: Eleven ciprofloxacin-resistant strains (with MICs ranging from 1 to 64 micrograms/mL) and two intermediate isolates (with MICs of 0.12 and 0.5 microgram/mL) were found. Mutations were identified by polymerase chain reaction and direct sequencing of the amplified products. RESULTS AND CONCLUSIONS: Alterations at Ser-91 and Asp-95 in GyrA were detected in all strains except one, an isolate for which the MIC was 0.12 microgram/mL. Alterations in ParC were more variable, and there was no clear correlation between the number of parC mutations and the level of resistance. No alterations at gyrB gene associated with ciprofloxacin resistance were found. The resistance was distributed among different types of strains, suggesting that the increase in the incidence of ciprofloxacin-resistant strains in Spain was not exclusively due to the appearance of a single-strain outbreak.     

Analysis of quinolone resistance mechanisms in Neisseria gonorrhoeae isolates in vitro

BACKGROUND AND OBJECTIVES: Gonococcal fluoroquinolone resistance is now a significant problem in Japan. We generated gonococcal mutants resistant to norfloxacin in vitro from norfloxacin sensitive isolates and analysed the contribution of three known mechanisms of quinolone resistance in Neisseria gonorrhoeae. MATERIALS AND METHODS: Three clinical isolates of N gonorrhoeae susceptible to norfloxacin were exposed to increasing concentrations of norfloxacin. To identify mutations in the gyrA and parC genes of the gonococcal mutants, the quinolone resistance determining regions of the gyrA and parC genes were polymerase chain reaction (PCR) amplified and the PCR products were directly sequenced. Norfloxacin accumulation in the gonococcal cells was also measured. RESULTS: The MICs of norfloxacin for three variants containing a single GyrA mutation were 16-fold higher than that for their parent isolates. A variant showing reduced norfloxacin accumulation in the cells, without mutations in the GyrA or ParC proteins, was also less sensitive to norfloxacin, with a 16-fold increase in the MIC, compared with the parent strain. The MIC of norfloxacin for a variant which contained a single GyrA mutation with reduced norfloxacin accumulation in the cells was 128-fold higher than for the parent strain. A variant containing mutations in both GyrA and ParC proteins with reduced accumulation of norfloxacin in the cells showed a 256-fold increase in the norfloxacin MIC compared with the parent strain. There was no variant containing a ParC mutation without the simultaneous presence of a GyrA mutation. CONCLUSIONS: The results from this study suggest that not only a mutation in the gyrA gene but also reduced drug accumulation in cells contributes to the development of fluoroquinolone a mutation in the gyrA gene contributes to a high level of fluoroquinolone resistance in gonococci with decreases in accumulation in cells having an additional but lesser effect.


     

Susceptibilities of Neisseria gonorrhoeae to fluoroquinolones and other antimicrobial agents in Hyogo and Osaka, Japan

OBJECTIVES: Decreasing susceptibility of Neisseria gonorrhoeae to fluoroquinolones has been reported in several countries. Knowledge of local N gonorrhoeae susceptibilities to various antimicrobials is important for establishing a rational treatment strategy in each region. METHODS: Isolates of N gonorrhoeae from male urethritis patients attending four urological clinics in Hyogo and Osaka prefectures in Japan were collected during 2002. The MICs for nine antimicrobials: penicillin G, tetracycline, cefixime, ceftriaxone, levofloxacin, gatifloxacin, ciprofloxacin, moxifloxacin, and spectinomycin were determined for each isolate. All isolates were also tested for beta lactamase producing profiles. RESULTS: Among the 87 isolates obtained, only one isolate was revealed to produce beta lactamase. MIC90 values for ciprofloxacin, levofloxacin, gatifloxacin, and moxifloxacin were over 8 microg/ml, over 8 microg/ml, 4 microg/ml, and 2 microg/ml, respectively. The proportion of isolates resistant to fluoroquinolones was over 60% (ciprofloxacin, 70.1%; levofloxacin, 65.5%; gatifloxacin, 70.1%). Chromosomally mediated penicillin and tetracycline resistance was identified in 12.6% and 33.3% of the isolates. MIC90 values for cefixime and ceftriaxone and were 0.5 microg/ml and 0.0063 microg/ml. All isolates were sensitive to ceftriaxone and 90.8% of them were sensitive to cefixime. MIC90 for spectinomycin was 32 microg/ml and all isolates were sensitive to it. Fluoroquinolone resistance correlated significantly with MICs for penicillin G but not tetracycline. CONCLUSION: Ceftriaxone and spectinomycin demonstrated lower MICs and so are recommended for N gonorrhoeae. Susceptibilities of N gonorrhoeae should be monitored periodically by region.     

Antimicrobial resistance patterns (1999-2002) and characterization of ciprofloxacin-resistant Neisseria gonorrhoeae in Korea

BACKGROUND: Antimicrobial susceptibilities of Neisseria gonorrhoeae were monitored during 4 years. In Korea, ciprofloxacin-resistant N. gonorrhoeae has dramatically increased after recommendation as a therapeutic drug. GOAL: The goal of this study was to determine the resistance patterns and characterize Korean ciprofloxacin-resistant N. gonorrhoeae. STUDY DESIGN: Antimicrobial susceptibilities were performed. PFGE profile and DNA sequencing of gyrA and parC genes were used to characterize the ciprofloxacin-resistant isolates in Korea. RESULTS: Tetracycline, ofloxacin, ciprofloxacin-resistant isolates were increased and among them, the proportion of isolates resistant to ciprofloxacin increased remarkably from 1% in 1999 to 48.8% in 2002. Fifteen different types by PFGE profile were identified. Major alteration type was M12 (67%), which have amino acid substitution in gyrA (S-91-->F, D-95-->G) and parC (S-87-->A). CONCLUSION: We could conclude that resistance for ciprofloxacin was remarkably increased during 4 years. Ciprofloxacin-resistant N. gonorrhoeae was supposed by the spread of several strains that had a small number of origins.     

Characterization of ciprofloxacin resistance in Neisseria gonorrhoeae isolates in Canada

BACKGROUND: Ciprofloxacin (500 mg orally, single dose) is one of the recommended therapies for gonorrhea in Canada. In Canada, the first ciprofloxacin-resistant (CipR) Neisseria gonorrhoeae strain was isolated in 1993. Antimicrobial susceptibilities of N gonorrhoeae isolates were monitored as part of a national surveillance program to ensure efficacy of antimicrobial therapies. GOAL: The goal was to determine the characteristics of ciprofloxacin resistance in Canadian gonococcal isolates. STUDY DESIGN: Susceptibility testing was performed on gonococcal strains from different provinces in Canada to determine the prevalence of CipR strains and their distribution. The CipR strains were further differentiated according to auxotype (A), serotype (S), plasmid profile (P), and pulsed-field gel electrophoresis (PFGE) profile. DNA sequencing and DNA microarray technology were used to determine mutations in gyrA and parC. RESULTS: In Canada, between 1997 and 1999, 4.8% of resistant strains (130 of 2687 antibiotic-resistant N gonorrhoeae isolates) were CipR (MICs of 1-32 microg/l) and belonged to 48 A/S/P classes. Sixty-eight of the strains that were not differentiated by A/S/P were subtyped into 47 classes with PFGE. DNA sequencing and DNA microarray showed that the most common mutations had amino acid substitutions of Ser-->Phe at codon 91 and Asp-->Gly at codon 95 of the gyrA and Ser-->Arg at codon 87 of parC. CONCLUSION: The CipR strains isolated in Canada are phenotypically and genotypically diverse, indicating that they were imported from overseas and not endemic in Canada. Mutations in gyrA and parC previously only identified by DNA sequencing were successfully identified with DNA microarray technology. DNA microarray technology could be an alternative tool for identifying point mutations in resistance genes or other epidemiologic markers when clinical laboratories replace culture methods with rapid and automated molecular methods for diagnosis.     

Mutation in DNA gyrase of norfloxacin-resistant clinical isolates of Neisseria gonorrhoeae.

BACKGROUND AND OBJECTIVES: Recently a rapid decrease in the susceptibility of Neisseria gonorrhoeae isolates to fluoroquinolones has occurred and gonococcal fluoroquinolone resistance is now a significant problem in the treatment of gonorrhoea in Japan. Thus, in order to investigate the quinolone resistance mechanisms in clinical isolates of N gonorrhoeae we studied an alteration in the DNA gyrase subunit A (GyrA) which is well-known as a common mechanism of bacterial quinolone resistance. MATERIALS AND METHODS: Four clinical isolates of N gonorrhoeae resistant to norfloxacin and 5 strains susceptible to norfloxacin, including 2 clinical isolates and 3 WHO reference strains, were tested in this study. To identify mutations in the GyrA genes of gonococcal strains, polymerase chain reaction and direct DNA sequencing were performed. RESULTS: A single base change (serine codon TCC changed to phenylalanine codon TTC), which resulted in an amino acid change in GyrA at position 91, was identified in all 4 norfloxacin-resistant strains for which the MICs of norfloxacin ranged from 1.0 to 8.0 micrograms/ml, while no mutation within GyrA was detected in 5 norfloxacin-susceptible strains for which the MICs of norfloxacin ranged from 0.004 to 0.063 microgram/ml. CONCLUSIONS: The results from this study suggest that the serine-91 to phenylalanine substitution in GyrA is probably an essential mutation in fluoroquinolone resistance in clinical isolates of N gonorrhoeae.     

广州淋球菌基因特征及其多抗原序列分型与环丙沙星耐药相关性研究

目的 探讨2014年广州市97株淋球菌环丙沙星耐药株的基因特征及其多抗原序列分型（NG-MAST）与淋球菌耐环丙沙星的相关性。 方法 用琼脂稀释法测定淋球菌对环丙沙星的最低抑菌浓度（MIC）,PCR分别扩增淋球菌的gyrA、parC基因和NG-MAST分型基因porB、tbpB基因并测序,获取耐药菌株的ST型别。 结果 97株淋球菌中95株（97.9%）对环丙沙星耐药。95株环丙沙星耐药菌株均在gyrA基因对应丝氨酸的第91和95位点上发生了突变,其中93株菌出现了parC基因突变。41株高水平耐药株（MIC ≥ 16 mg/L）中35株（85.4%）出现了parC基因87位点突变,54株低水平耐药株中32株（59.3%）出现此突变,差异有统计学意义（χ2 = 7.64,P < 0.05）。96株淋球菌分离株配对后,50株为网站已编号型别,共35个不同的ST型,其中10个ST型含有2 ~ 4个不同的分离株,ST型别中最常见ST5309。对淋球菌菌株系统进化树分析,淋球菌流行株可分为两群,第1群84株中MIC ≥ 16 mg/L的菌株39株占46.4%,第2群12株中只有1株MIC值为16 mg/L,差异有统计学意义（χ2 = 6.27,P = 0.012）。 结论 淋球菌对环丙沙星的高水平耐药主要与parC基因87位点突变相关。NG-MAST分型与环丙沙星耐药程度高低可能存在相关性。     

Susceptibility of gonococci isolated in London to therapeutic antibiotics: establishment of a London surveillance programme. London Gonococcal Working Group

OBJECTIVES: To establish the in vitro susceptibility of gonococci isolated in the London area to antibiotics in current therapeutic use and to establish a sentinel surveillance system for monitoring trends in antibiotic resistant gonorrhoea in London. METHODS: Isolates of Neisseria gonorrhoeae from consecutive patients attending genitourinary medicine clinics at 10 hospitals in the London area were collected over a 3 month period, May to July 1997. The susceptibility to penicillin, ciprofloxacin, tetracycline, and spectinomycin was determined for each isolate. Isolates exhibiting either plasmid or chromosomally mediated resistance were additionally tested for susceptibility to agents used as alternative treatments including azithromycin, ceftriazone, and ofloxacin. The resistant isolates were also tested for plasmid profiles (penicillinase producing N gonorrhoeae, PPNG), type of tetM determinant (tetracycline resistant N gonorrhoeae, TRNG), and presence of gyrA and parC mutations (quinolone resistant N gonorrhoeae, QRNG). RESULTS: A total of 1133 isolates were collected which represents > 95% of the total gonococci isolated in the 3 months. Plasmid mediated resistance was exhibited by 48 (4.2%) isolates; six (0.5%) were PPNG, 15 (1.3%) were PP/TRNG, and 27 (2.4%) were TRNG. The majority of PPNG (18 of 20 tested) carried the 3.2 MDa penicillinase plasmid whereas the two types of tetM determinant were more evenly distributed. High level resistance to ciprofloxacin was detected in four (0.4%) isolates and double mutations were found in the quinolone resistance determining region (QRDR) of the gyrA gene in three QRNG with MICs of 16 mg/l and a single mutation in one isolate with a MIC of 1 mg/l to ciprofloxacin. No parC mutations were found. Of the remaining 1081 isolates, 86 (8.0%) were chromosomally mediated resistant N gonorrhoeae (CMRNG). CONCLUSIONS: A unique collection of gonococcal isolates has been established which can be used as a baseline for surveillance of susceptibility to antibiotics and for epidemiological purposes.     

染色体介导淋球菌耐药机制的进展

染色体介导的与青霉素及与四环素耐药相关的主要位点包括penA、ponA、penB、penC、mtr及tet。青霉素结合蛋白中出现镶嵌状结构是头孢菌素低敏的原因之一。喹诺酮耐药决定区gyrA和parC不同的位点突变导致喹诺酮耐药。淋球菌对大观霉素高度耐药是由于spe位点单步突变所致。多重耐药与多种位点突变相关。     

解脲脲原体的耐药性分析及其耐氟喹诺酮的分子机制研究

目的检测128株临床分离解脲脲原体(UU)对9种药物的敏感性,并检测喹诺酮类耐药UU对5种喹诺酮药物的MIC以及gyrA和parC基因突变情况。方法应用支原体分离鉴定、计数药敏试剂盒检测UU对9种药物的敏感性,用微量肉汤稀释法检测耐药UU菌株对5种喹诺酮类药物的MIC,用PCR和DNA测序及序列比较检测基因突变。结果UU对多西环素最敏感,其次为米诺环素、交沙霉素、司帕沙星及克林霉素,对大环内酯类药物阿奇霉素和罗红霉素高度耐药。而司帕沙星、加替沙星和左氧氟沙星的MIC范围在0.25～8μg/mL,抑制UU活性强于氧氟沙星和环丙沙星。10株喹诺酮类耐药UU中有3株只有parC基因第80位TCA→TTA的突变,氨基酸由丝氨酸→亮氨酸,1株GyrA基因第95位密码子GAC→GAA的突变,氨基酸由天冬氨酸→谷氨酸。6株两者同时存在。结论在UU治疗中可首选多西环素,其次为米诺环素和交沙霉素。gyrA基因95位密码子和parC基因80位的突变密码子与UU耐喹诺酮类药物密切相关。     

解脲脲原体临床分离株中喹诺酮类耐药株的筛选及其耐药基因的研究

目的：从临床分离的解脲脲原体中筛选出喹诺酮类药物耐药株,了解耐药株发生的比率。并研究耐药株中喹诺酮抗性决定区域(QRDR)出现基因变异的情况。方法：采用药敏试剂盒及96孔微量培养基稀释法收集解脲脲原体的喹诺酮耐药株。PCR扩增阳性标本测序后比较基因变异情况。结果：从104株解脲脲原体临床分离株中筛选出10株耐药株。测序结果显示有7株QRDR的gyrA基因片段中309位均出现了A→G点变异,导致相应编码的氨基酸由组氨酸变为精氨酸。结论：解脲脲原体对喹诺酮类药物的耐药与QRDR中gyrA基因的点变异可能相关。     

广州地区106株淋球菌中脂蛋白分型与环丙沙星耐药相关性研究

目的:研究广州地区106株淋球菌中脂蛋白分型与环丙沙星耐药的相关性.方法:用糖琼脂稀释法测定淋球菌对环丙沙星的MIC值,PCR分别扩增淋球菌的gyrA、parC和脂蛋白基因并测序分析.结果:广州地区106株淋球菌对环丙沙星的耐药率为95 3%,共有19个脂蛋白亚型,最常见的亚型是17c,有49株(46 2%).对环丙沙...     

广州地区106株淋球菌中脂蛋白分型与环丙沙星耐药相关性研究

目的:研究广州地区106株淋球菌中脂蛋白分型与环丙沙星耐药的相关性.方法:用糖琼脂稀释法测定淋球菌对环丙沙星的MIC值,PCR分别扩增淋球菌的gyrA、parC和脂蛋白基因并测序分析.结果:广州地区106株淋球菌对环丙沙星的耐药率为95 3%,共有19个脂蛋白亚型,最常见的亚型是17c,有49株(46 2%).对环丙沙星耐药的101株菌中,所有菌株在gyrA基因对应氨基酸的第91和95位点上均发生了突变,而parC基因随着MIC值的升高发生位点突变的概率呈上升趋势.在中低水平耐药组中,最常见的脂蛋白亚型是17c和14d,均有12株(28 6%).在高水平耐药组中,最常见的脂蛋白亚型是17c,有35株(59 3%),其次是14d,有11株(18 6%).结论:淋球菌脂蛋白亚型的分布存在地域性,与环丙沙星耐药程度高低无明显相关性.     

淋球菌氟喹诺酮耐药性的分子机制探讨

目的：探讨GyrA、ParC基因变异与淋球菌氟喹诺酮耐药性的相关关系。方法：首先对78株淋球菌临床分离株环丙沙星最低抑菌浓度(MIC)进行检测和G、TA、ParC基因进行PCR扩增，然后分别将2株敏感菌、2株中介菌和8株耐药菌的GyrA、ParC基因进行DNA序列测定。结果：所有78株淋球菌均扩增出GyrA、ParC基因；2株敏感菌和1株中介菌的GyrA、ParC基因未发现突变，另外1株中介菌中和8株耐药菌中GyrA、ParC基因发现有一个或多个位点突变。结论：GwA、ParC基因变异可能是导致淋球菌氟喹诺酮耐药的重要分子机制。     

High-frequency of quinolone-resistant Neisseria gonorrhoeae in Austria with a common pattern of triple mutations in GyrA and ParC genes

OBJECTIVE: Quinolones have a broad spectrum of antimicrobial activity and are widely used for the treatment of uncomplicated Neisseria gonorrhoeae infections. A dramatic increase in the number of reported N. gonorrhoeae infections as well as quinolone-resistant isolates in Vienna prompted us to investigate the pattern of mutations in these isolates. GOALS: The goal of this study was to investigate the pattern of mutations in GyrA and ParC genes in quinolone-resistant N. gonorrhoeae clinical isolates in Vienna from 1999 to 2002. STUDY: The antibiotic susceptibility of N. gonorrhoeae clinical isolates and point mutations of the GyrA and ParC genes of 104 clinical isolates were analyzed. RESULTS: Quinolone-resistant N. gonorrhoeae isolates increased from 3.9% (3 of 77) in 1999 to 59.4% (120 of 202) in 2002. As expected, none of the 46 N. gonorrhoeae quinolone-sensitive strains showed mutations at these positions of GyrA and ParC genes with the exception of 1 isolate, which had a single mutation at GyrA 91. Unlike what has been previously reported for other geographic areas, 96.6% (56 of 58) of the quinolone-resistant isolates harbored common triple mutations at Gyr 91, 95, and ParC 86. The majority of these isolates (76.8%) belong to the PPNG phenotype. CONCLUSIONS: Our data indicate that the pattern of mutations in GyrA and ParC subunits of N. gonorrhoeae in Austria differs from that reported from other geographic areas. The differences may either be the result of the difference in bacterial subtypes or various antibiotic regimens used in these regions.     

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.     

Reduced susceptibility to azithromycin and high percentages of penicillin and tetracycline resistance in Neisseria gonorrhoeae isolates from Manaus, Brazil, 1998

BACKGROUND: The identification of Neisseria gonorrhoeae isolates resistant to antimicrobial agents currently recommended for the treatment of gonococcal infections continues to escalate globally. Thus, in some areas, resistance to fluoroquinolone drugs is commonplace; several reports document resistance to third-generation cephalosporins, and the sporadic isolation of spectinomycin-resistant isolates continues unabated. Gonococcal resistance to azithromycin, an antibiotic used for the primary treatment of gonococcal infections in some Latin American countries, also has been described. Because the prevalence of resistant isolates is insufficiently documented in many areas of Latin America, the efficacy of locally recommended therapies for gonococcal infections is often unknown. GOAL: To determine the antimicrobial susceptibility and strain types of N gonorrhoeae isolates collected in Manaus, Brazil. These data will establish antimicrobial susceptibility baseline data for the region as a reference point for future surveillance. STUDY DESIGN: Consecutive N gonorrhoeae isolates from urethral and endocervical specimens were collected and examined for identity, antimicrobial susceptibility, and strain type (plasmid content, tetM type, auxotype, and serovar). RESULTS: Most of the isolates (65/81; 85.2%) were resistant to tetracycline, penicillin, or both, with the majority (n = 62) carrying plasmid-mediated resistance to tetracycline (tetracycline-resistant N gonorrhoeae [TRNG]). All of the TRNG contained the Dutch-type tetM plasmid, and 18 were A/S class NR/IA-02. Penicillinase-producing N gonorrhoeae comprised 8.2% (7/81) of the isolates. Of these seven isolates, four also were TRNG, and two carried chromosomal resistance to tetracycline. The isolates were susceptible to ciprofloxacin, spectinomycin, and ceftriaxone. However, 23 isolates were characterized by reduced susceptibility to azithromycin (MIC, 0.25-0.5 microg/ml), and one isolate had reduced susceptibility to ciprofloxacin (MIC, 0.25 microg/ml). CONCLUSIONS: This study supports the continued use of third-generation cephalosporins, spectinomycin, and fluoroquinolone drugs for the primary treatment of gonococcal infections in Manaus. The occurrence of isolates with reduced susceptibility to azithromycin and ciprofloxacin underscores the importance of ongoing antimicrobial susceptibility monitoring to support decisions regarding appropriate drugs for the treatment of gonococcal infections.     

High prevalence of Neisseria gonorrhoeae strains with reduced susceptibility to fluoroquinolones in Japan.

OBJECTIVE--To study the antibiotic susceptibility of Neisseria gonorrhoeae strains isolated in Japan and, in particular, to examine the possibility of emerging fluoroquinolone resistance. MATERIALS AND METHODS--Sixty-nine strains of Neisseria gonorrhoeae isolated in 1992 were tested for susceptibility to 15 antibiotics including fluoroquinolones and were seroclassified. Twenty-seven strains isolated from 1981 to 1984 were also evaluated as controls. RESULTS--The MIC90 values of norfloxacin, ofloxacin, and ciprofloxacin against the isolates from 1992 were 2.0, 1.0, and 0.5 microgram/ml, respectively. The MIC90 values of norfloxacin, ofloxacin, and ciprofloxacin against the isolates from 1981-84 (controls) were 0.25, 0.125, and 0.063 microgram/ml, respectively. These results indicate that the MIC90 values of norfloxacin, ofloxacin, and ciprofloxacin against the strains from 1992 were 8-fold higher than those against the strains from 1981-84. However, there were no significant differences in susceptibility to beta-lactams, tetracyclines, macrolides, and spectinomycin between the isolates from 1992 and those from 1981-84. The majority of the isolates belonged to the WII/WIII serogroup. There was no relationship between fluoroquinolone resistance and serogroup. CONCLUSIONS--Fluoroquinolones have been used frequently as first-line therapy and have provided excellent clinical efficacy for gonococcal infections for the last several years in Japan. However, our data indicate that a rapid decrease in the susceptibility of Neisseria gonorrhoeae to fluoroquinolones is occurring in our country.