2008-2009年中国部分地区脑膜炎奈瑟菌对体外抗生素敏感性检测

目的了解2008-2009年中国部分地区脑膜炎奈瑟菌(Nm)分离株的抗生素敏感性变化趋势。方法药敏纸片扩散(K-B)法和E-test试纸条检测方法对本研究室2008-2009年收集的68株分离自患者和健康带菌者菌株进行体外抗菌药物敏感性检测。结果所有菌株对3种治疗药物头孢噻肟、头孢曲松和氯霉素均敏感,1株C群患者菌株对美洛培南耐药,13株对青霉素不敏感菌株,6株对氨苄西林不敏感菌株。6种预防用药组中,除1株Y群带菌者菌株对利福平耐药外,其他菌株对阿奇霉素、米诺环素和利福平均敏感,70.59%菌株对萘啶酸,72.06%对环丙沙星,95.59%对复方新诺明耐药。W135群带菌者菌株对青霉素和氨苄西林敏感株比例较大,2株对磺胺类药物敏感。患者菌株和带菌者菌株药敏谱略有不同。结论磺胺类和喹诺酮类药物仍不被考虑作为流脑的预防性药物,加强对青霉素和氨苄西林治疗药物在各种血清群Nm的耐药性监测。长期对Nm药敏监测非常必要,对流行性脑脊髓膜炎预防和治疗药物的选择应因时因地而宜。     

Antimicrobial resistance in Streptococcus pyogenes isolates in Berlin

A total of 212 clinical Streptococcus pyogenes isolates were tested for susceptibility to various antibiotics by agar dilution. The overall frequency of erythromycin resistance was 12.7%, being higher in isolates from children (18.9%) than in those from adult patients (10.7%). Similar results were found for clarithromycin, while 2.8% of the isolates were resistant to ciprofloxacin. All strains were susceptible to penicillin and cefotaxime. Of the erythromycin-resistant isolates subjected to the double-disc diffusion test for erythromycin and clindamycin, 35% expressed constitutive and 55% inducible resistance to clindamycin. Ten per cent were susceptible to clindamycin (M-phenotype). Thus, a high rate of macrolide resistance in S. pyogenes has emerged in Berlin.     

In vitro susceptibility of Haemophilus equigenitalis, the causative organism of contagious equine metritis 1977, to antimicrobial agents.

The in vitro susceptibility of recent clinical isolates of Haemophilus equigenitalis to various antimicrobial agents was determined by the disk diffusion test and the World Health Organization-International Collaborative Study agar dilution procedure. Ampicillin and tetracycline were the most active drugs. All strains were susceptible to beta-lactam antibiotics, chloramphenicol, trimethoprim-sulfamethoxazole, nalidixic acid, nitrofurantoin (Furadantin), and bacitracin. All but two strains were resistant to streptomycin, whereas all strains were susceptible to the other aminocyclitol antibodies. All strains were resistant to clindamycin, lincomycin, and metronidazole.     

Serotype distribution of penicillin-resistant pneumococci and their susceptibilities to seven antimicrobial agents

A total of 229 clinical isolates of Streptococcus pneumoniae recovered from 225 patients were serotyped and tested for susceptibility to penicillin G, ampicillin, mezlocillin, cefazolin, erythromycin, clindamycin, chloramphenicol, and sulfamethoxazole-trimethoprim. Of all the isolates, 48 (21.0%) showed intermediate resistance and 17 (7.4%) showed resistance to penicillin G. Penicillin-resistant strains had higher minimal inhibitory concentrations of ampicillin, mezlocillin, and cefazolin than did penicillin-susceptible strains. Resistance to erythromycin and clindamycin was rare (1.3 and 0.9%, respectively). Of the isolates, 8.7% were resistant to sulfamethoxazole-trimethoprim, and all were susceptible to chloramphenicol. Penicillin resistance was associated with 13 serotypes. Serotypes 14, 19F, 19A, and 23F were both highly prevalent and frequently penicillin resistant.     

High prevalence of erythromycin-resistant, clindamycin/miocamycin-susceptible (M phenotype) Streptococcus pyogenes: results of a Spanish multicentre study in 1998. Spanish Group for the Study of Infection in the Primary Health Care Setting

Using the standard agar dilution method we studied the prevalence of susceptibility to 14-, 15- and 16-membered ring macrolides and clindamycin in Streptococcus pyogenes isolated in 1998 from 21 laboratories in Spain. The number of strains admitted to the study was proportional to the numbers of inhabitants in each geographical area. We also determined the susceptibility phenotypes and the genetic basis for the antibiotic resistance. A total of 486 unduplicated isolates of S. pyogenes were used. Throat swab samples provided 359 (73.9%) isolates, and the remaining 127 isolates were from other sources. One hundred and fourteen (23.5%) isolates were resistant to erythromycin, a 14-membered ring macrolide, and azithromycin, a 15-membered macrolide, whereas only 1% of isolates were resistant to miocamycin, a 16-membered macrolide and 0.8% were resistant to clindamycin. Of the 114 erythromycin-resistant strains, 109 (95.6%) were susceptible to clindamycin and miocamycin. Since induction with erythromycin did not modify susceptibility to the latter antibiotics, these 109 strains were considered to have the M phenotype. Twenty strains with the M phenotype, one per laboratory, were assayed by PCR and showed the presence of the mef gene, which is responsible for antibiotic resistance by an efflux system. Among comparable studies covering entire countries, ours demonstrates one of the highest rates of S. pyogenes erythromycin resistance and clindamycin and miocamycin susceptibility in the world. Strains with the M phenotype account for the great majority of these isolates.     

Antimicrobial resistance of Streptococcus pneumoniae isolates in 1999 and 2000 in Madrid, Spain: a multicentre surveillance study

Resistance to first-line antimicrobial agents in Streptococcus pneumoniae is increasing worldwide and the new fluoroquinolones may provide a good alternative. The antimicrobial susceptibility to levofloxacin and 13 other antibiotics of 300 isolates of S. pneumoniae, isolated in the Madrid community in 1999 and 2000, was determined. A total of 65.6% of isolates were penicillin intermediate or resistant strains. A high percentage of resistance to macrolides, clindamycin, tetracycline and chloramphenicol was also observed, mainly in penicillin-resistant strains. All but one strain was susceptible to levofloxacin.     

Methicillin-Resistant Staphylococcus aureus Susceptibility Testing by an Automated System, Autobac I

The Autobac I system was used to evaluate the antibiotic susceptibility pattern of methicillin-resistant Staphylococcus aureus isolates. The results of the Autobac I were compared with the results of the disk diffusion method. The disk diffusion susceptibility pattern showed resistance to methicillin/oxacillin, penicillin, erythromycin, clindamycin, and kanamycin. All isolates were susceptible to cephalothin, chloramphenicol, tetracycline, and gentamicin. There was at least 96% agreement using the Autobac I system with all antibiotics except methicillin and clindamycin. Seventy percent of 57 isolates were recorded as susceptible to methicillin, whereas 9% had an intermediate susceptibility. With clindamycin, 14% were recorded as susceptible and 7% were recorded as intermediate. Upon prolonged incubation of the Autobac I cuvette, the agreement between the two methods was 44% for methicillin and 93% for clindamycin. Changes in the environmental conditions, such as use of 5% sodium chloride broth and a 32 degrees C incubation temperature, did not increase the detection of methicillin-resistant isolates by the Autobac I system.     

Novel mechanisms of resistance to lincosamides in Staphylococcus and Arthrobacter spp.

Clinical isolates of Staphylococcus and Arthrobacter spp. were screened for lincosamide resistance. Six different patterns of resistance were found. Strains designated SF27 and SF28 showed low-level resistance to lincosamides: one was susceptible to erythromycin (SF27) and the other was resistant (SF28). Analysis of ribosomes from the resistant strains in an in vitro poly(U)-dependent protein-synthesizing system showed that ribosomes of both strains were sensitive to lincomycin and clindamycin. Four patterns of high-level resistance to lincosamides were observed (strains SF4, SF19, SF30, and SF31). All of these except SF30 had ribosomes which were highly resistant in vitro to the antibiotics and showed a close correlation with results of the in vivo experiments. In vivo protein synthesis by strain SF30 was resistant to lincomycin and sensitive to clindamycin, whereas the ribosomes were sensitive when assayed in vitro. Lincosamide-inactivating enzymes were not detected in cell extracts of the six resistant strains. Strains SF19 and SF31 demonstrated two ribosome-mediated lincosamides resistance mechanisms that were not previously reported. Both strains were highly resistant to lincosamides and susceptible to erythromycin, but SF19 was also highly resistant to oleandomycin and partially resistant to various macrolides.     

Comparison of antimicrobial susceptibility patterns of Campylobacter jejuni and Campylobacter coli

To determine whether employing antibiograms is useful to separate Campylobacter jejuni and Campylobacter coli, we determined the MICs of 12 antibiotics for 104 human clinical strains and 74 swine strains. Of 74 swine strains, 5 (7%) were hippurate positive, as were 93 (89%) of 104 human strains. The 12 antimicrobial agents tested were ampicillin, amoxicillin, clindamycin, chloramphenicol, erythromycin, furazolidone, norfloxacin, nalidixic acid, rosoxacin, rosaramicin, tetracycline, and Sch 32063. Isolates from humans were significantly (P less than 0.001) more susceptible than swine strains to clindamycin, erythromycin, rosaramicin, and Sch 32063. Of 11 human hippurate-negative strains, 3 (27%) were resistant to clindamycin, erythromycin, rosaramicin, and Sch 32063, compared with 1 of 93 (1%) hippurate-positive strains. Nearly all human and swine strains were susceptible to furazolidone and nalidixic acid. Campylobacter isolates from humans and swine have different antibiograms, and the susceptibility to certain antibiotics, such as clindamycin, may be helpful for differentiation of C. jejuni from C. coli.     

In vitro activities of clindamycin, imipenem, metronidazole, and piperacillin-tazobactam against susceptible and resistant isolates of Bacteroides fragilis evaluated by kill kinetics

The aim of the present study was to investigate the activities of clindamycin, imipenem, metronidazole, and piperacillin-tazobactam against 12 Bacteroides fragilis isolates (resistant and susceptible strains) by kill kinetics over 24 h. In contrast to the other antimicrobial agents, clindamycin did not affect strains with MICs of >8.0 μg/ml. For those strains with MICs of ≤ 8.0 μg/ml, all employed antibiotics except clindamycin showed nearly bactericidal activity. Metronidazole proved to be the most active antimicrobial agent.     

Susceptibility of Various Serogroups of Streptococci to Clindamycin and Lincomycin

The minimal inhibitory concentration of lincomycin and clindamycin for a large number of strains from multiple serogroups of streptococci was determined. The median minimal inhibitory concentration for streptococci from groups A, B, C, F, G, H, L, and M and nongroupable organisms ranged from 0.02 to 0.39 mug of lincomycin per ml and from 相似文献   

2003-2012年中国部分地区脑膜炎奈瑟菌体外抗生素敏感性分析

目的 了解我国脑膜炎奈瑟菌对抗生素敏感性的变化趋势. 方法 对2003-2012年本研究室收集的脑膜炎奈瑟菌菌株,根据分离年份、血清群和来源(患者或健康携带者)选择487株,采用微量肉汤稀释法和E-test浓度梯度扩散法,对其进行体外12种抗生素敏感性检测和分析. 结果 所有菌株对头孢噻肟、头孢曲松、阿奇霉素、美洛培南、氯霉素和米诺环素均敏感;对青霉素和氨苄西林不敏感的菌株分别是4.9%(24/487)和3.5%(17/487),75.6%(368/487)的菌株对萘啶酸耐药,87.1%(424/487)对复方新诺明耐药,48.9%(238/487)对环丙沙星耐药.从2005年开始出现对环丙沙星耐药的菌株23.8%(24/101),从2006年开始出现对青霉素类药物不敏感菌株2.4%(2/82).患者和健康携带者来源的菌株对萘啶酸、复方新诺明和环丙沙星3种药物显现不同的耐药率. 结论 我国流脑菌株对磺胺类和喹诺酮类药物具有较高的耐药性,对青霉素类药物不敏感的菌株也逐渐增多.这种耐药性与菌株分离年份、血清群和菌株来源具有相关性.     

2006年浙江省流行性脑脊髓膜炎监测结果分析

目的 了解2006年浙江省流脑流行病学特征及流脑菌株的药物敏感性特点.方法 对2006年全省上报的流脑病例进行描述流行病学分析.设立3个监测点进行健康人群抗体水平和带菌率检测,并对分离到的流脑菌株进行抗生素的耐药性检测.结果 2006年浙江省流脑发病率为0.16/10万,病例以A群为主,同时存在C群和B群病例.健康人群中A群抗体保护率(70.65%)远远高于C群(6.52%),流脑菌株带菌率为1.71%,B群占62.50%.所有菌株均对青霉素、氯霉素等9种抗生素敏感,部分菌株对复方新诺明、左氧氟沙星、环丙沙星耐药,且不同血清群、不同来源菌株的耐药程度不同.结论 浙江省流脑病例以A群为主,C群比例有上升趋势.流脑菌株对一些抗生素具有耐药性,需全面监测病例和健康带菌者流脑菌株的耐药性特征.     

Nosocomial streptococcal blood stream infections in the SCOPE program: Species occurrence and antimicrobial resistance

Nosocomial blood stream infections due to streptococci represent an increasingly important problem, particularly among neutropenic cancer patients. This problem is compounded by the emerging resistance to antimicrobial agents commonly used for empiric or prophylactic treatment of hospitalized patients. In this study, we examined the species distribution and antimicrobial susceptibility profile of 295 streptococcal nosocomial blood stream isolates from more than 30 U.S. medical centers (SCOPE National Surveillance Program). Streptococci accounted for 5.9% of all nosocomial blood stream isolates reported. The viridans group streptococci (VGS) were the most frequently isolated streptococci (50.8%), followed by the β-haemolytic streptococci (31.9%) and pneumococci (13.2%). The β-haemolytic streptococci were dominated by serogroup B strains (63%), followed by serogroups A and G. Of these organisms, 193 strains were referred for subsequent monitor susceptibility testing. Approximately 14% of S. pneumoniae, 9.2% of VGS, and 0% of β-haemolytic streptococci were resistant to penicillin. Ceftriaxone was highly active against virtually all isolates (93–100% susceptible) except the VGS (77% susceptible). The rank order for activity of the four agents tested against the 193 isolates was vancomycin > ceftriaxone > penicillin > erythromycin. Importantly, 69% of the penicillin intermediate and resistant strains of VGS were also resistant to at least one additional antimicrobial (31% resistant to ceftriaxone, 51% resistant to erythromycin, 15% resistant to both ceftriaxone and erythromycin). The relatively poor activity of erythromycin against virtually all streptococci and the frequent association of macrolide resistance with penicillin resistance among the VGS suggests that both macrolides and β-lactam agents might have limited values as prophylactic agents for dental procedures and in empiric or prophylactic use in neutropenic patients.     

Prevalence of resistance to macrolide, lincosamide and streptogramin antibiotics in Gram-positive cocci isolated in a Korean hospital

To investigate the prevalence of resistance to macrolide, lincosamide and streptogramin (MLS) antibiotics in Gram-positive cocci isolated in a Korean hospital, we tested the antibiotic susceptibility of 1097 clinical isolates of Staphylococcus aureus, coagulase-negative staphylococci (CNS) and enterococci to the macrolides erythromycin, clarithromycin, azithromycin and josamycin, the lincosamide clindamycin and the streptogramin pristinamycin. These three groups of organisms were mostly resistant to macrolides and lincosamide, but were commonly susceptible to pristinamycin. The resistance phenotypes of erythromycin-resistant isolates were determined by the double-disc test with erythromycin and clindamycin, which showed that most exhibited constitutive MLS resistance. In order to determine the prevalence of the resistance genotypes and the resistance mechanisms, the presence of the erm(A), erm(B), erm(C) and mef genes in the erythromycin-resistant isolates was identified by PCR analysis. The resistance was due mainly to the presence of erm(A) in S. aureus (82.5%), erm(B) in enterococci (55%) and erm(C) in CNS (47.2%).     

In-vitro study of the susceptibility of cefoxitin/cefotetan resistant Bacteroides fragilis group strains to various other antimicrobial agents

The in-vitro activity of various beta-lactam antibiotics, beta-lactam/beta-lactamase inhibitor combinations, clindamycin, and metronidazole was determined against Bacteroides fragilis group isolates that were resistant to both cefoxitin and cefotetan. Among the cephalosporins tested ceftizoxime was the most active with 80% of the strains susceptible, followed by cefotaxime (65% susceptible), and cefoperazone (47% susceptible). Piperacillin and clindamycin showed comparable activity to ceftizoxime with 80% and 81% susceptible, respectively. The addition of a beta-lactamase inhibitor (sulbactam, clavulanate, or tazobactam) enhanced the activity of the various beta-lactam agents from 4-fold to 16-fold overall. One strain of B. fragilis was found that was resistant to all beta-lactam agents either alone or in combination. All strains in this study were susceptible to less than or equal to 4 mg/l of metronidazole.     

Prevalence and association of macrolide-lincosamide-streptogramin B (MLS(B)) resistance with resistance to moxifloxacin in Clostridium difficile

Clostridium difficile remains the leading cause of nosocomially acquired diarrhoea. C. difficile usually exhibits resistance against beta-lactam antibiotics, whereas susceptibility to other drugs may vary. This study investigated the antimicrobial susceptibility of C. difficile to different antibiotics over a period of time and characterizes molecular mechanisms for resistance. One hundred and seventy-three toxigenic and 19 non-toxigenic C. difficile strains, recovered from patients in two university hospitals in Germany between 1986 and 2001, were investigated for their susceptibility to erythromycin, clindamycin, moxifloxacin, vancomycin and metronidazole employing the Etest. The genetic background for resistance was analysed using PCR and DNA sequencing. All strains were susceptible to vancomycin and metronidazole. Resistance to erythromycin, clindamycin and moxifloxacin was found in 27%, 36% and 12% of the tested strains, respectively. High-level resistance (MIC > 128 mg/L) against erythromycin and clindamycin was detected in 25% of the strains tested. Thirty-four of the macrolide-lincosamide-streptogramin B (MLS(B))-resistant strains carried the erythromycin resistance methylase gene. The results indicate an increase in the prevalence of resistance to MLS(B) and fluoroquinolone antibiotics in C. difficile. Fluoroquinolone resistance is associated with resistance to MLS(B) antimicrobials.     

Antimicrobial susceptibility of Haemophilus influenzae

Selected clinical isolates of Haemophilus influenzae were tested for their susceptibility to seven antibiotics by a microtiter broth dilution and an agar diffusion method. Eleven of 40 strains tested were resistant to ampicillin, the drug of choice, by both methods. All the strains tested were susceptible to chloramphenicol, and all but one were susceptible to tetracycline. Of the other four antibiotics tested, the ranges of minimal inhibitory concentrations (MICs) were: 0.5 to 4 mug of gentamicin per ml, 0.5 to 4 mug of erythromycin per ml, and 2 to 16 mug of clindamycin per ml. MICs of ampicillin for both the susceptible and resistant strains were markedly affected by inoculum concentration. The ampicillin MICs of the resistant strains were also affected by the time of incubation.     

Correlation between ampicillin-sulbactam resistance and penicillin-binding protein gene variation in acinetobacter baumannii北大核心CSCD

Objective To determine the susceptibility of Acinetobacter baumannii isolates to commonly used antibiotics, characterize mutation status of penicillin-binding protein (pbp) gene and analyze the association between pbp gene and ampicillinsulbactam resistance. Methods A total of 67 A. baumannii strains were collected from four teaching hospitals in Shanghai. The minimum inhibitory concentrations of antibiotics were determined for A. baumannii by agar dilution method. PCR and gene sequencing were conducted to analyze 7 pbp genes in all stains. The nucleotide sequence was compared between the strains susceptible to ampicillin-sulbactam and the strains resistant to ampicillin-sulbactam. Results The A. baumannii isolated from patients showed high resistance rate to common antibiotics, 67.6% resistant to ampicillin-sulbactam. Sequencing analysis showed that no amino acid variation was found for all 7 pbp genes whether the strains were susceptible or resistant. Conclusions Clinical isolates of A. baumannii are highly resistant to ampicillin-sulbactam, while pbp gene is not involved in the mechanism of ampicillinsulbactam resistance. © by Editorial Department of Chinese Journal of Infection and Chemotherapy.