In vitro activity of the pristinamycin against the isolated staphylococci in the french hospitals in 1999-2000

One thousand six hundred and fifty clinically significant, consecutive and non redundant strains of staphylococci, including 863 Staphylococcus aureus and 787 coagulase negative staphylococci (CNS), were isolated between October 1999 and March 2000 in 35 French hospital laboratories. Susceptibilities were determined in each center by a standard diffusion method according to the recommendations of CA-SFM. Strains with vancomycin zone size diameter <17 mm were sent to the central laboratory for MIC determination of vancomycin by agar dilution, as recommended by the CA-CSFM. Frequencies of resistance to oxacillin were 38.6% for S. aureus (MRSA), 54% for the CNS, all species and 62% for S. epidermidis, respectively. The antibiotics tested showed a good activity against strains of S. aureus susceptible to oxacillin, more than 95% of strains being susceptible except for erythromycin (82.6%). Against MRSA, vancomycin and prisitinamycin had the highest rates of susceptible strains, greater than 93% for the later antibiotic. More than 92% of strains of CNS susceptible or resistant to oxacillin were sensitive to pristinamycin. Pristinamycin displayed a good activity whether the strains were constitutively or inducibly resistant to MLS(B). It comes out from this in vitro study that the rate of resistance of staphylococci to pristinamycin remains weak and stable in France. Pristinamycin is a good alternative for oral treatment of staphylococcal infections.     

In vitro study of the effects of an imipenem-fosfomycin combination against clinical strains of Staphylococcus

In vitro antibacterial activity of imipenem-fosfomycin (IMP-FOS) combinations were studied against 31 clinical isolates of Staphylococcus strains: methicillin susceptible S. aureus (MSSA, 11 strains), methicillin resistant S. aureus (MRSA, 11 strains), methicillin resistant S. epidermidis (MRSE, 9 strains). The study was carried out by means of a microtiter checkerboard method (FICs and FBCs index) and killing-curves (3 strains). Imipenem antibacterial activity was good against MSSA (mean MICs of 0.12 micrograms/ml) but reduced against MRSA (16 micrograms/ml). Fosfomycin was regularly effective (CMI less than or equal to 64 micrograms/ml) against most strains. IMP-FOS combination was strongly synergistic (FIC less than 0.125) against MSSA and still synergistic with achievable therapeutic concentrations against heterogeneous MRSA and MRSE strains (mean FIC of 0.125, MIC in the combination of 1 microgram/ml). The bactericidal activity (FBCs and killing-curves) was limited against homogeneous MRSA and MRSE needing higher concentrations (8 micrograms/ml in the combination). In the 3 cases fosfomycin concentrations in combination remained low (1 to 2 micrograms/ml).     

Antimicrobial resistance in coagulase-negative staphylococci

Patterns of resistance to antimicrobial agents were studied in 193 strains of coagulase-negative staphylococci isolated from hospital patients. Strains isolated from patients with malignant disease were significantly more often resistant to sulphonamide, trimethoprim, gentamicin and methicillin than were strains from other sources. Susceptibility to various beta-lactam antibiotics and aminoglycosides was investigated in members of the two most frequent species: Staphylococcus epidermidis and S. haemolyticus. S. haemolyticus strains were not only more often resistant to methicillin than S. epidermidis strains (respectively 81% and 17%) but they were more highly resistant (mean MICs respectively 85 and 19 mg/L). Methicillin-resistant S. haemolyticus strains were highly resistant to nine other beta-lactam antibiotics, whereas methicillin-resistant S. epidermidis strains showed both lower levels and a narrower spectrum of cross-resistance. Resistance to methicillin in members of both species was "heterogeneous", i.e., only a minority of cells in a culture showed significant resistance. Almost all gentamicin-resistant strains were sensitive to netilmicin and amikacin; rifampicin, vancomycin and teicoplanin were also highly active in vitro.     

汕头大学医学院附属第一医院耐甲氧西林金黄色葡萄球菌(MRSA)耐药谱分析

目的:了解汕头大学医学院附属第一医院分离的92株耐甲氧西林金黄色葡萄球菌(MRSA)的耐药情况。方法:琼脂稀释法测定17种抗菌药物对MRSA的最低抑菌浓度(MIC)。结果:92株MRSA对实验中所有β-内酰胺类抗生素的耐药率均在80%以上。绝大部分菌株对庆大霉素、红霉素、氟喹诺酮类也不敏感。超过半数的MRSA菌株对利福平保持敏感,对氯霉素、多西环素及米诺环素也普遍敏感,未发现耐万古霉素的MRSA菌株。结论:我院附属第一医院的MRSA呈多重耐药,但对氯霉素,半合成四环素及万古霉素仍然敏感。     

Antibiotics resistance of meticilline-resistant Staphylococcus aureus: detection of the first glycopeptides low sensibility strains in Tunisia

The adaptation of Staphylococcus aureus to the hospital environment led to the acquisition of resistance to all antibiotics available in clinical practice. The aim of this study was to investigate the methicillin-resistant Staphylococcus aureus (MRSA) strains isolated in the F. Bourguiba hospital of Monastir (Tunisia). We determined the antibiotype of all Staphylococcus aureus strains identified. Susceptibility rates to fosfomycin, chloramphenicol, rifampicin and pristinamycin were 7%, 3%, 2% and 0%, respectively. The prevalence of MRSA was 15.5% (96 strains); their susceptible to gentamicin progressively increased. The minimum inhibitory concentration (MICs) of oxacillin, vancomycin and teicoplanin were evaluated for the 96 MRSA strains. We identified two MRSA strains (M4 and M41) showing reduced glycopeptides susceptibility. Further analysis revealed that M4 and M41 harbor the gene encoding the class S and class F proteins specific for the Panton-Valentine Leukocidin (PVL). The mecA gene was detected only in strain M41 which harbors the Staphylococcal Cassette Chromosome (SCCmec) type III. This is the first reported MRSA showing reduced susceptibility to glycopeptides in Tunisia. Regulatory surveillance of susceptibility to antibiotics is needed to reduce the morbidity and the mortality rates as well as societal costs of S. aureus infections.     

Quality control of direct molecular diagnostics for methicillin-resistant Staphylococcus aureus

Ten samples containing various amounts of methicillin-resistant Staphylococcus aureus (MRSA), methicillin-susceptible S. aureus, methicillin-resistant Staphylococcus epidermidis (MRSE), and combinations thereof were distributed to 51 laboratories for molecular diagnostics testing. Samples containing 10(2) to 10(3) MRSA cells were frequently reported to be negative. MRSE samples were scored as negative by all commercial tests but by only two out of three in-house tests.     

Emergence of homogeneously methicillin-resistant Staphylococcus aureus.

Forty-seven clinical isolates of methicillin-resistant Staphylococcus aureus (MRSA), collected between 1986 and 1990 from 29 institutions, were analyzed for susceptibility to various antibiotics. Twenty-six strains were homogeneously methicillin resistant (i.e., greater than or equal to 10% of the cells in these strains were able to grow on Mueller-Hinton agar containing 50 micrograms of methicillin per ml). The MICs of gentamicin, clindamycin, trimethoprimsulfamethoxazole, methicillin, and imipenem for homogeneous MRSA strains were higher than those for heterogeneously resistant strains. Both types of strains were, for the most part, susceptible to vancomycin and trimethoprim-sulfamethoxazole. Ciprofloxacin-resistant MRSA strains were not isolated prior to 1988 but made up 40% of the post-1987 strains. The level of methicillin resistance correlated well with the imipenem MIC, suggesting that susceptibility to imipenem may serve as a marker to identify and monitor the prevalence of homogeneous MRSA strains.     

2016年某院金黄色葡萄球菌感染分布及耐药性分析

目的 对2016年秦皇岛市第一医院患者金黄色葡萄球菌感染情况及耐药特点进行调查,为感染监控和临床用药提供参考.方法 回顾性分析2016年住院患者细菌培养标本中金黄色葡萄球菌的分离情况及耐药性.结果 共分离金黄色葡萄球菌311株,其中耐甲氧西林金黄色葡萄球菌(MRSA) 108株,占34.7％.金黄色葡萄球菌感染的标本来源主要有痰液(46.95％)、分泌物(34.73％)和全血(9.64％);感染科室主要以重症监护室、神经外科、儿科、老年病科、骨科多见.药物敏感性试验结果显示,MRSA耐药率明显高于甲氧西林敏感金黄色葡萄球菌(MSSA),未发现对万古霉素、替加环素耐药的菌株,对利奈唑胺和喹努普汀/达福普汀、呋喃妥因的敏感率也很高,但对克林霉素、红霉素耐药率达70％以上,而对青霉素的耐药率高达97.1％.结论 甲氧西林敏感金黄色葡萄球菌(MSSA)对部分抗菌药物仍保持较好的敏感性,而MRSA表现为多重药耐药性,应引起临床高度重视,临床应根据药物敏感性试验结果合理使用抗菌药物.     

Epidemiological study of staphylococcal colonization and cross-infection in two West African Hospitals

Surveillance in two medium-size (250-300 beds) hospitals located in the most populated islands of Cape Verde was undertaken in July 1997 in order to obtain data concerning nasal carriage of staphylococci. Nasal swabs (172) taken from inpatients and health care workers (HCW) from different internment services yielded 68 Staphylococcus aureus and 105 coagulase-negative staphylococcal (CNS) isolates, demonstrating extensive colonization of both inpatients and HCW by S. aureus (carriage rate 41%) and CNS (carriage rate 65%). The most frequent CNS species were S. epidermidis and S. haemolyticus. Three species--S. aureus, S. epidermidis, and S. sciuri-were recovered from wound swabs. The antibiotic susceptibility profiles of S. aureus and CNS differed sharply: all 68 S. aureus were resistant to penicillin but were fully susceptible to oxacillin as well as the other antimicrobial agents tested-gentamicin; erythromycin, except for three strains; ciprofloxacin; sulfamethoxazole-trimethoprim, except for two strains; vancomycin; and amoxicillin/clavulanate. In contrast, most (91/105) of CNS were resistant to both penicillin and oxacillin, and a variable but substantial proportion of CNS isolates also carried multiresistant traits to gentamicin, erythromycin, sulfamethoxazole-trimethoprim, and amoxicillin/clavulanate. The analysis by PFGE of the methicillin-susceptible S. aureus (MSSA) and the methicillin-resistant S. epidermidis (MRSE) strains provided evidence for extensive cross-infection and cross-colonization from HCW to patients.     

Methicillin resistance among isolates of Staphylococcus aureus: antibiotic sensitivity pattern & phage typing

Out of 3988 clinical specimens from hospital admitted patients 230 strains of Staphylococcus aureus were isolated, 45 strains (19.56%) were Methicillin resistance Staphylococcus aureus (MRSA). All MRSA strains were beta lactamase producers. Multidrug resistance was observed among MRSA strains more commonly than in methicillin sensitive strains of Staphylococcus aureus (MSSA). Maximum strains were resistant to penicillin (100%), co-trimoxa zole (97%) & chloramphenicol (93.33%). As least resistant to gentamicin & ciprofloxacin shown by MRSA, these drugs can be used in few situations after susceptibility test. All strains of MRSA were sensitive to vancomicin (100%). Majority of strains (34 out of 45) showed MIC values of 4 ug/ml. Twenty eight out of 44 strains were non typable using routine phages. Study revealed that MRSA with associated multidrug resistance is common in this region. There is need to develop local set of MRSA phages for improvement of typability.     

Epidemiology of methicillin-resistance among Staphylococci strains isolated in risk units and effects of the vancomycin on the expression of methicillin-resistance

Four hundred Staphylococci strains, isolated from different in intensive care unit hospitalized patients, were analyzed. 53% of all strains were resistant to methicillin. Against methicillin-resistant S. aureus (MRSA), teicoplanin and vancomycin (100% of susceptibility), rifampin (76.3%) and co-trimoxazole (73%) emerged as the most potent drugs tested; the 15% of the strains were susceptible to ciprofloxacin, erythromycin, clindamycin and gentamicin. Only one MRSA strain (0.8%) resulted hetero-resistant to vancomycin. Among 100 strains exposed to serial concentration of vancomycin (0.25-32 mg/L for 30 days), 57 were selected with intermediate-level of resistance to the glycopeptides; the MRSA strains have shown to acquire resistance in vitro more easily than methicillin-susceptible. These results indicate that in the clones of Staphylococci circulating in our region, the evolution of glycopeptides-resistance is not a rapid process and the loss of effectiveness of these antibiotics cannot be predicted to short term. In particular, the restriction profile analysis of chromosomal DNA from MRSA strains, selected in vitro with intermediate -level of vancomycin resistance, demonstrated that at the moment in the hospital departments studied, the diffusion of a clone able to acquire resistance more easily than others is not present.     

耐甲氧西林金黄色葡萄球菌的临床分布及耐药性分析

目的 熟悉耐甲氧西林金黄色葡萄球菌（MRSA）的临床分布及其耐药性,为临床提供参考。方法 采用VITEK2 COMPACT全自动微生物分析系统进行鉴定,筛选出MRSA菌株。结果 2017年1~12月我院分离出459株金黄色葡萄球菌,其中MRSA 98株,检出率为21.4%。儿科、创伤修复烧伤整形外科、神经外科检出MRSA较多。98株MRSA中,耐药率较高的抗菌药物有青霉素G、红霉素、克林霉素和四环素,万古霉素、利奈唑胺和呋喃妥因敏感率均为100.00%。结论 我院MRSA的检出率和耐药率形式仍然严     

烧伤患者医院感染病原菌分布及耐药变迁分析

目的了解烧伤病房感染病原菌分布及耐药变迁特点。方法回顾海南省人民医院2002-2009年住院烧伤感染患者病原菌的分布,并对比前、后4年病原菌构成比及耐药情况。结果检出634株病原菌,其中革兰阴性（G-）杆菌389株（61.4%）,主要为铜绿假单胞菌196株（30.9%）、鲍曼不动杆菌89株（14.0%）和大肠埃希菌56株（8.8%）;革兰阳性（G＋）球菌220株（34.7%）,主要为金黄色葡萄球菌109株（17.2%）和表皮葡萄球菌79株（12.5%）;真菌25株（3.9%）。前、后4年里,铜绿假单胞菌及金黄色葡萄球菌的构成比有下降趋势（P〈0.05）,而条件致病菌如鲍曼不动杆菌、表皮葡萄球菌的构成比呈明显上升趋势（P〈0.01）;铜绿假单胞菌、鲍曼不动杆菌对第三代头孢菌素、喹诺酮类抗生素的耐药率有上升趋势（P〈0.05）。109株金黄色葡萄球菌中耐甲氧西林金黄色葡萄球菌（MRSA）52株（47.8%）,对万古霉素100%敏感。结论近8年来烧伤病房患者感染病原菌以G-杆菌为主,条件致病菌的检出率呈上升趋势;常见病原菌对第三代头孢菌素的耐药率呈上升趋势,对此应予以重视。     

A high frequency of macrolide-lincosamide-streptogramin resistance determinants in Staphylococcus aureus isolated in South Korea

Genes conferring resistance to one of the macrolide-lincosamide-streptogramin (MLS) antibiotics may confer cross-resistance to others, because they have similar effects on bacterial protein synthesis. In Korea, over 70% of Staphylococcus aureus isolates are methicillin-resistant and erythromycin-resistant methicillin-resistant S. aureus (MRSA) is also prevalent. We investigated the frequency of MLS resistance in erythromycin-resistant S. aureus isolates. A total of 682 isolates of S. aureus were collected in a nationwide antibiotic resistance survey. Susceptibility to erythromycin, clindamycin, and quinupristin/dalfopristin was tested by disk diffusion. In all, 37% of the methicillin-susceptible S. aureus (MSSA) and 97% of the MRSA isolates were resistant to at least one of the MLS antibiotics, whereas all were susceptible to quinupristin/dalfopristin. Out of 518 strains that were resistant to erythromycin, 60 clindamycin-susceptible (30 MSSA, 30 MRSA) and 44 clindamycin-resistant isolates (14 MSSA, 30 MRSA) were selected at random from these strains. Thirteen genes related to MLS resistance were detected in these isolates by PCR. Of the 104 MSSA and MRSA strains tested, 98 harbored one or more erm gene. The most common was erm(A), with erm(C) next. But, msr(A), lnu(A), and mef(A) were rare and no resistance to streptogramin A was encountered.     

Profile and sensitivity to antibiotics of 115 staphylococcal strains implicated in septicemia in a Tunisian general hospital

Staphylococci remain among the main responsible bacteria for septicemia. The resistance to antibiotics already makes a prognosis difficult. We carried out a study on Staphylococcus isolated from blood culture on 3 years in general hospital in Tunisia. We present the different species and their sensitivity to antibiotics. S. aureus is the predominant isolated species. S. epidermidis is essentially isolated in newborn intensive care unit. The meticillino-resistance concerns 14% of the whole strains and 5.2 of the S. aureus. No resistance is found as regard the vancomycin and the pristinamycin; ofloxacine is inactive on 14.8% of strains and the gentamicine on 11.3%. The resistance of staphylococci of our study is lower than the rates reported in southern Europe and in North America.     

Molecular Epidemiology of Oxacillin-resistant Staphylococcus aureus and in vitro Activity of Glycopeptides against Staphylococcus species

Oxacillin resistant Staphylococcus aureus and coagulase negative Staphylococcus species (MRSA and MRSCoN)have become major pathogens in nosocomial infections.The first MRSA isolate in the world was identified in En gland in 1961 [1]. Since that tim…     

Resistance mechanisms of gram-positive bacteria

The introduction and increasing use of antibiotics for antibacterial therapy has initiated a rapid development and expansion of antibiotic resistance in microorganisms, particularly in human pathogens. Additionally, a shift to an increase in number and severity of Gram-positive infections has been observed the last decades. Common to these pathogens is their tendency to accumulate multiple resistances under antibiotic pressure and selection. Methicillin-resistant Staphylococcus aureus (MRSA), that have acquired multiresistance to all classes of antibiotics, have become a serious nosocomial problem. Recently, the emergence of the first MRSA with reduced vancomycin susceptibility evoked the specter of a totally resistant S. aureus. Problems with multiresistance expand also to penicillin-resistant Streptococcus pneumoniae that are partially or totally resistant to multiple antibiotics, and to vancomycin-resistant Enterococcus ssp., completely resistant to all commonly used antibiotics. The rapid development of resistance is due to mutational events and/or gene transfer and acquisition of resistance determinants, allowing strains to survive antibiotic treatment.     

Molecular characterization and antibiotic susceptibility of Staphylococcus aureus from a multidisciplinary hospital in Romania

From 2004 to 2005, 60%-72% of invasive Staphylococcus aureus isolates from Romanian hospitals were resistant to methicillin (methicillin-resistant S. aureus [MRSA]), the highest frequency for any European nation. Few reports, however, have addressed the molecular characteristics of S. aureus in Romania. In this study, we utilized spa typing, multilocus sequence typing, staphylococcal cassette chromosome mec (SCCmec) typing, dru typing, pulsed-field gel electrophoresis, and detection of virulence factors to characterize 146 S. aureus strains isolated from 2004 to 2005 at the Clinic County Hospital in Bra?ov. Antibiotic susceptibility patterns for all MRSA isolates and patient demographic data were also obtained. Fifty-six strains (38.4%) were determined to be MRSA by susceptibility testing and SCCmec typing. All MRSA strains were resistant to beta-lactams and tetracycline, but susceptible to nitrofurans, vancomycin, and clindamycin, with inducible clindamycin resistance in 23/28 clindamycin-sensitive/erythromycin-resistant isolates. Molecular typing identified 15 clonal backgrounds (CC 1, 5, 8, 8/239, 9, 15, 20, 22, 25, 30, 45, 80, 97, 101, and 121), only 4 of which were associated with MRSA (CC 1, 8/239, 30, and 80). Spa types 35 (t127, CC 1) and 351 (t030, CC 8/239) accounted for 27.4% and 21.9% of all S. aureus strains, respectively, and 19.6% and 57.1% of all MRSA strains. Both hospital-associated (SCCmec type III) and community-associated (SCCmec type IV) elements were identified within MRSA strains, whereas Panton-Valentine leukocidin was detected in 10 MRSA and 12 methicillin-sensitive S. aureus strains. These results demonstrate the presence of various endemic S. aureus clones within the Clinic County Hospital in Bra?ov, suggestive of ongoing nosocomial and community transmission.     

2013-2015年金黄色葡萄球菌的临床分布及耐药性分析

目的：分析徐州医科大学附属医院2013—2015年金黄色葡萄球菌的临床分布及耐药情况,为临床用药提供依据。方法：收集2013年1月1日至2015年12月31日各类标本检出的金黄色葡萄球菌,临床分离株药敏实验采用标准纸片扩散(K-B)法,结果采用WHONET5.6进行分析。结果：2013—2015年共检出金黄色葡萄球菌1725株,主要来源于痰液(35.4%),在ICU(43.7%)和神经外科(12.6%)检出率最高。2013—2015年,耐甲氧西林金黄色葡萄球菌(methicillin-resistant Staphylococcus aureus, MRSA)检出率分别为63.3%,59.8%,57.6%。MRSA耐药率大于50.0%的抗菌药物有庆大霉素(53.2%~73.1%)、妥布霉素(62.8%~64.9%)、环丙沙星(67.2%~75.3%)、红霉素(86.6%~92.9%)、四环素(53.5%~65.0%);甲氧西林敏感金黄色葡萄球菌(methicillin-sensitive Staphylococcus aureus,MSSA)对抗生素的耐药率排在前3位的为青霉素(85.4%~93.3%)、红霉素(68.7%~72.4%)、复方新诺明(46.3%~57.9%)。结论：本院分离的金黄色葡萄球菌主要分布在ICU和神经外科,MRSA的耐药率普遍较高,临床医生应根据耐药性合理选用抗菌药物。     

Nationwide German multicenter study on prevalence of antibiotic resistance in staphylococcal bloodstream isolates and comparative in vitro activities of quinupristin-dalfopristin

Antibiotic-resistant gram-positive bacteria have become an increasing problem in the last two decades. In order to evaluate the prevalence of antibiotic resistance in staphylococcal bloodstream isolates in Germany, 2,042 staphylococci collected in 21 tertiary-care hospitals were investigated during a 3-year period (March 1996 to March 1999). Altogether, 1,448 S. aureus isolates and 594 coagulase-negative staphylococci (CoNS) that comprised 13 different species were included. Furthermore, the antistaphylococcal activities of quinupristin-dalfopristin were compared with those of eight other compounds by the broth microdilution method. The rates of oxacillin resistance in Staphylococcus aureus, S. epidermidis, S. haemolyticus, and other CoNS were 13.5, 69, 90, and 34%, respectively. In oxacillin-resistant strains high rates of resistance (up to 100%) to erythromycin, clindamycin, ciprofloxacin, and gentamicin were also observed. However, no strain appeared to be resistant to vancomycin or quinupristin-dalfopristin. The streptogramin combination exhibited excellent in vitro activity against all staphylococcal species tested, regardless of the patterns of resistance to other drug classes. In terms of MICs at which 90% of the isolates are inhibited, quinupristin-dalfopristin was 2 times more active against S. aureus isolates, 4 to 16 times more active against S. haemolyticus, and 8 to 32 times more active against S. epidermidis than vancomycin or teicoplanin.