Susceptibility to selected coagulase-negative chemotherapeutic agents of methicillin resistant staphylococci isolated from clinical materials in 1997-1998

The study was aimed at assessment of the sensitivity of methicillin-resistant coagulase-negative staphylococci isolated from clinical material in 1997/1998 to selected chemotherapeutic agents. The investigated material comprised 96 methicillin-resistant coagulase-negative staphylococci from hospital and ambulatory infections isolated during the period from April 1997 to May 1998. Species affiliation was determined by classical identification methods and commercial diagnostic tests for identification of staphylococci. Methicillin resistance was determined by agar disk-diffusion method and screening. Sensitivity to chemotherapeutics was determined by agar disk-diffusion method and agar dilution methods. All the investigated strains were sensitive to nitrofurantoin, furazolidone and vancomycin. To teicoplanin--the second glycopeptide antibiotic--84% strains were sensitive, whereas the percentages of resistant and moderately sensitive strains amounted to 5.2% and 10.4%, respectively. 85% and 82% of coagulase-negative staphylococcal strains were sensitive to fusidic acid and mupirocin. Considerable differences were noted with respect to sensitivity to aminoglycoside group antibiotics. About 35% of strains were sensitive to gentamicin, and 90% sensitive to netilmicin. Ca. 40% of coagulase-negative staphylococci were resistant both to cotrimoxazole and trimethoprim, which, in view of 98% resistance to the second component of cotrimoxazole, may be associated with the activity of only one of the components of the drug--trimethoprim.     

Incidence of Staphylococcus aureus isolated from patients treated at the Clinical Center of Skopje, Macedonia, with special attention to MRSA

The distribution of 3497 Staphylococcus aureus strains according to methicillin resistance, specimens, departmental profession and antibiotic resistance patterns was analysed. The strains were cultured from the patients of the Clinical Center of Skopje, Macedonia, between 1 January 2002 and 31 December 2004. The majority of the isolates was obtained from suppurated wounds (28.5%), nares (21%), intratracheal tubes (13%) and blood cultures (11.8%). Overall 1100 (31.4%) of the isolates was methicillin-resistant with 1 microg oxacillin disc. Of these 35.5%, 30.5% and 10.4% were cultured from wounds, intratracheal tubes and blood samples, respectively. The prevalence of MRSA strains was 78.6%, 75%, 44.2% and 37.3% in specimens of ICU, Coma Center, General Surgery and Haematology patients. There were extremely big differences in the frequency of MRSA between departments with particular specialisation. The 2397 MSSA isolates belonged to practically one antibiotic resistance pattern characterised with penicillin resistance and susceptibility to other antistaphylococcal drugs. The 1100 MRSA isolates distributed to four antibiotic resistance patterns on the basis of their resistance to oxacillin, penicillin, amoxicillin+clavulanic acid, azithromycin, clindamycin, amikacin, gentamicin, ciprofloxacin, trimethoprim+sulphamethoxasole, vancomycin and teicoplanin. All the MRSA isolates were multidrug resistant but sensitive to glycopeptides.     

The extreme drug resistance (XDR) Staphylococcus aureus strains among patients: A retrospective study

The objective of the present work was to observe and profile various antibiotic resistant strains of Staphylococcus aureus and highlight the need for continuous surveillance. Data regarding antibiotic-resistant S. aureus strains isolated and identified at the Medical Microbiology Department, King Khalid Hospital, Riyadh was obtained. Bacterial isolates were collected from several sites of infections in patients and an evaluation of susceptibility were carried out using a fully automated Vitek2 system. Relative frequency (%), odds ratios and Ward's minimum variance were calculated. The results showed that wounds were a source of more than 40% of the S. aureus (MRSA) strains that have ability to resist methicillin, and more than 45% of the methicillin-susceptible S. aureus (non-MRSA) strains. 40% of the isolates were MRSA (N = 251), and all MRSA strains were sensitive to vancomycin, daptomycin, teicoplanin, tigecycline, nitrofurantoin, and itraconazole while all non-MRSA (N = 338) strains were sensitive to vancomycin, cefoxitin, daptomycin, gentamicin, oxacillin, teicoplanin, tigecycline, and mupirocin. Strength of association between antibiotic-resistant S. aureus strains and source of samples (site of infection) was established. The study concluded that S. aureus strains had developed resistance towards 20 (for non-MRSA) and 22 (for MRSA) of the antibiotics tested. All MRSA strains were non-sensitive to amoxicillin/clavulanate, ampicillin cefoxitin, cefazolin, imipenem, oxacillin, and penicillin.     

耐甲氧西林金黄色葡萄球菌的分布及耐药性分析

目的分析医院耐甲氧西林金黄色葡萄球菌（MRSA）的分布及耐药情况,为临床治疗金黄色葡萄球菌医院感染提供科学依据。方法对618株金黄色葡萄球菌进行常规鉴定,用K—B法对其进行药敏试验。结果5年MRSA的平均检出率为51．9％（321／618）,MRSA感染高发主要科室为ICU、神经外科、神经内科,MRSA检出率前三位的科室为神经外科（84．1％）、ICU（76．3％）、呼吸内科（61．3％）,标本来源主要为痰液,占67．3％,检出率82．4％。MRSA对万古霉素、替考拉宁、利奈唑胺保持100％敏感,对氯霉素、米诺环素、复方新诺明等的耐药率较低,对其他药物都保持了65％以上的高耐药率。结论对重点科室监控,合理使用抗生素,严格执行无菌操作,采取有效的消毒隔离,尽量减少侵袭性操作等措施是控制并减少MRSA感染的重要环节。     

Evaluation of susceptibility to antibiotics of Staphylococcus aureus strains resistant to methicillin]

Methicillin-resistant strains of Staphylococcus aureus (MRSA) constitute a serious diagnostic and therapeutic problem. Over 500 strains of Staphylococcus aureus were tested for susceptibility to methicillin. By application of a screening method, 13.7% of these strains were classified as methicillin-resistant. Over 95% of these strains were isolated from hospital infections. Applying criteria of belonging of these strains to methicillin-resistance classes it was found that 49.3% belonged to class II, 31.2% to class III and 19.5% to class IV. Analysis of susceptibility to antibiotics of MRSA strains demonstrated significant differences between class II and between class III and IV in resistance to imipenem, gentamycin, erythromycin and tetracycline. All tested strains were susceptible to ciprofloxacin, ofloxacin, vancomycin and teicoplanin. The screening method (25 mg methicillin/l of TSA medium) results in obtaining of univocal results of determination of methicillin-resistance in S. aureus.     

Vibrio cholerae non-O1, non-O139 strains isolated before 1992 from Varanasi, India are multiple drug resistant, contain intSXT, dfr18 and aadA5 genes

In this study, we report the presence of the SXT element and Class I integron in Vibrio cholerae non-O1, non-O139 strains isolated from Varanasi, India. Isolates were resistant to cotrimoxazole, trimethoprim and/or streptomycin, furazolidone and ampicillin. None contained plasmids. Polymerase chain reaction (PCR) and DNA sequencing revealed the presence of antibiotic resistance gene cassettes, aadA1 , aadA2 , aadA5 and dfrA15 , in the Class I integron and SXT, an integrative conjugative element containing dfr18 , sulII and strAB , in three and six of the isolates respectively. Conjugation experiments, followed by PCR analysis of transconjugants, provided evidence for the transferable nature of int SXT and associated antibiotic resistance gene cassettes. This is the first report of the occurrence of SXT ICE, dfr18 , sulII , strAB and aadA5 genes in environmental V. cholerae non-O1, non-O139 strains from Varanasi, India, that had been isolated before 1992.     

耐甲氧西林金黄色葡萄球菌对万古霉素的MIC 值的5 年监测

目的:了解我院5年来耐甲氧西林金黄色葡萄球菌(MRSA)对万古霉素敏感性的变化,为临床治疗和控制该类感染提供依据方法:采用以肉汤稀释法测定近5年耐甲氧西林金黄色葡萄球菌(MRSA)临床分离株对万古霉素的最低抑菌浓度(MIC),按NC-CLS/CLSI2010年标准判定结果,WHONET5.5软件进行数据分析。结果:MRSA检出率从2005年的19.23%上升到2009年的42.14%,万古霉素的M IC几何均数从0.54μg/ml上升到1.21μg/ml,未检出万古霉素、替考拉宁耐药株,但2007年有2株,2008年、2009年各有1株菌株对替考拉宁呈中介,抑菌圈直径依次为12 mm、12 mm、13 mm、12 mm,MIC值均为16.0μg/ml。结论:MRSA检出率逐年上升,MRSA对万古霉素MIC值有升高的趋势,加强金黄色葡萄球菌对万古霉素敏感性的监测非常必要。     

Antibiotic Resistance and Molecular Epidemiology of Methicillin-Resistant Staphylococcus aureus from Lower Respiratory Tract: Multi-resistance and High Prevalence of SCCmec III Type

We sought to study antibiotic resistance and molecular epidemiology of methicillin-resistant Staphylococcus aureus (MRSA) from lower respiratory tracts of patients in Shanghai Pulmonary Hospital. Hundred and seven strains of MRSA were isolated from the patients of nine wards. The tests for antibiotic resistance (Kirby–Bauer paper dispersion method), the Panton–Valentine Leukocidin (PVL) and Staphyloccoccal Cassette Chromosome mec (SCCmec) genes (PCR), and homology analysis (32 randomly selected MRSA strains; pulsed-field gel electrophoresis) were carried out. All 107 strains were susceptible to vancomycin, teicoplanin, and linezolid, but highly or completely resistant to tetracycline, gentamicin, clindamycin, levofloxacin, azithromycin, erythromycin, trimethoprim/sulphamethoxazole, and ciprofloxacin. All 107 strains were negative for PVL gene. Most of the strains (81.3 %) were SCCmec III type, while the SCCmec II and IV types were less frequent (15.9 and 2.8 %, respectively). No SCCmec I or V types were detected. The homology analysis test showed that 32 MRSA strains could be divided into 4 groups: type A (25 strains), type B (5 strains), type C (1 strain), and type D (1 strain). The type A included 3 subtypes: A1 (17 strains), A2 (1 strain), and A3 (7 strains). Further, most of the strains were isolated from the same wards or units (e.g., intensive care unit or tuberculosis wards) within a short period of time, indicating an outbreak status. In conclusion, the observed MRSA from low respiratory tracts from patients at Shanghai Pulmonary Hospital were multiple-resistant, with the SCCmec III being the main documented genotype.     

Methicillin-resistant Staphylococcus aureus (MRSA) with high resistance to mupirocin in hospitals of the Gdańsk region

Occurrence of high-level mupirocin resistance in methicillin-resistant Staphylococcus aureus (MRSA) strains isolated from 18 hospitals in Gdańsk area was determined. The study was carried out on 190 MRSA isolated in 1997-2000 from various clinical samples. The strains were tested for high-level mupirocin resistance by 200 micrograms mupirocin disc. The minimum inhibitory concentrations (MIC) for methicillin were estimated by agar dilution. Sensitivity to other antibiotics was determined in disc-diffusion method and to vancomycin in agar dilution method additionally. The strains were typed by set of 10 experimental phages and compared by the method of PCR-RFLP analysis of coagulase gen restriction fragment length polymorphism. There were low frequency of high-level mupirocin resistance in MRSA strains (4.7%) that were found only in 3 hospitals, in 6 patients. All of them were high-resistant also to methicillin and resistant to doxycyclin, gentamycin, erytromycin, klindamycin, ciprofloksacin, rifampicin, resistant or intermediate sensitive to fusidic acid but sensitive to vancomycin, teikoplanin and bacitracin. The origin all of the MRSA strains high-resistant to mupirocin probably was the same, except one strain, because they were belonged to one genetic type and possessed the same phage pattern.     

猪源致病性金黄色葡萄球菌的分离鉴定及其耐药性分析

目的鉴定引起猪渗出性皮炎的病原,并分析猪源致病性金黄色葡萄球菌的耐药性,为临床用药提供依据。方法采集患渗出性皮炎的仔猪标本进行细菌分离培养,联合应用形态学检查、生理生化试验和PCR方法鉴定分离菌株,并进行致病性和药物敏感性试验。结果先后从病猪标本中分离鉴定获得PSA1、PSA2、PSA3和PSA4四株金黄色葡萄球菌,其中PSA1和PSA3分离株的致病性较强。药敏试验结果显示PSA1、PSA2和PSA3分离株为MRSA菌株,PSA4分离株为MSSA菌株。MRSA菌株对14种抗菌药物均呈现不同程度的耐药,尤其是对青霉素、链霉素、四环素、强力霉素、环丙沙星和氧氟沙星等6种抗菌药物的耐药率达100%。所有分离株对万古霉素与替考拉宁均敏感。结论合肥地区猪渗出性表皮炎的病原为金黄色葡萄球菌。猪源致病性金黄色葡萄球菌合肥分离株具有多重耐药性,治疗猪渗出性皮炎应建立在体外药敏试验的基础上,有针对性选择抗菌药物。     

武汉地区医院感染葡萄球菌的耐药性监测

目的了解武汉地区医院感染葡萄球菌的耐药现状。方法采用回顾性分析方法,对2003年1月到2007年12月我院分离的1373株金黄色葡萄球菌和259株表皮葡萄球菌的耐药性进行分析。药敏试验采用K—B纸片法,判断标准根据美国临床实验室标准化委员会（NCCLS）的标准。结果2003年1月到2007年12月我院分离到金黄色葡萄球菌1373株,其中耐甲氧西林的金黄色葡萄球菌（MRSA）有697株,对甲氧西林敏感株（MSSA）有587株,表皮葡萄球菌有259株,其中耐甲氧西林的表皮葡萄球菌（MRSE）有92株,对甲氧西林敏感株（MSSE）有142株。MRSA、MRSE对临床常用的抗生素几乎均耐药,只有对万古霉素和替考拉宁100％敏感;MSSA、MSSE对临床常用抗生素较敏感,但是对青霉素和红霉素耐药率均大于70％。结论武汉地区医院感染MRSA和MRSE对大部分临床常用抗生素均已高度耐药,对万古霉素和替考拉宁依然高度敏感。了解医院感染葡萄球菌的耐药状况,对临床合理选用抗生素十分重要。     

Detection of methicillin-resistance (mec-A) gene inStaphylococcus aureus strains by PCR and determination of antibiotic susceptibility

Methicillin-ResistantStaphylococcus aureus (MSRA) has become a frequent cause of serious infections. Extended hospitalization and antibiotic therapy have been identified as additional risk factors for MRSA carrier and infection. The aim of this study was to determine the incidence of MRSA infections in the hospitals affiliated to Hamedan University of Medical Sciences. SeventyS. aureus clinical strains were isolated from patients from June 2005 to June 2006 and examined by PCR and conventional microbiological tests. Then, the antibiotic susceptibility to methicillin/oxacillin and other antibiotics were performed by Disc Diffusion Agar (DDA). The results of this study showed that methicillin resistance gene was detected in 35 (50%) and 22 (31.4%) cases by PCR and DDA, respectively. The results of antibiotic susceptibility assays also showed there were high resistance MRSA strains to penicilin (100%), cloxacillin (91.4%), tetracycline (74.2%), cotrimoxazole (68.5%), erythromycin (68.5%) and less resistance to rifampin (11.4). Two MRSA also had decreased susceptibility to vancomycin. But the strains of Methicillin-SensitiveS. aureus (MSSA) showed high sensitivity to all antibiotics profiles except to penicillin (complete resistance). As a conclusion, the resistance to methicillin/oxacillin ofS. aureus in Hamedan hospitals has reached to 50% and they show multidrug resistance.     

肠球菌的临床感染与耐药性分析

目的了解温州医学院附属第一医院临床分离主要肠球菌的分布及其对常用抗菌药物的耐药现状,以指导临床合理用药。方法对2008年至2011年临床分离的635株粪肠球菌和屎肠球菌的标本来源和药敏结果进行回顾性分析。结果各种临床标本中两种肠球菌的分布比例存在差异,总体以尿液标本所占比例最多,且屎肠球菌的总体分离率高于粪肠球菌。粪肠球菌对利奈唑胺、氨苄西林、万古霉素、呋喃妥因和替考拉宁的耐药率都在5．0％以下,对莫西沙星和青霉素G的耐药率也仅为7．0％和6．7％;屎肠球菌对莫西沙星、左旋氧氟沙星、环丙沙星、氨苄西林、青霉素G和红霉素的耐药率都在90．0％以上,对利奈唑胺、万古霉素、替考拉宁和奎奴敏感。粪肠球菌的多重耐药株占总数的26．4％,屎肠球菌的多重耐药株占总数的78．2％。结论粪肠球菌和屎肠球菌对15种抗菌药物的耐药情况不同,屎肠球菌具有更高的耐药率和更广的耐药谱。临床应根据药敏试验的结果合理选择抗菌药物,以防止耐药菌株的产生和播散。     

1272例尿液标本细菌培养结果及耐药性分析

目的调查临床送检中段尿标本菌群分布及体外抗生素耐药性,为临床合理使用抗生素提供依据。方法回顾性分析2010年1月至2012年6月住院患者送检中段尿标本中,分离的1272株细菌（剔除重复菌株）临床分布及耐药性。采用美国BDphoenix100全自动细菌鉴定药敏分析仪进行菌种鉴定及药敏试验,结合相关临床资料,应用WHONET5．6分析软件进行耐药性分析。结果从分离到的l272株细菌中,检出前5位的细菌是大肠埃希菌、肺炎克雷伯菌、屎肠球菌、粪肠球菌和铜绿假单胞菌,构成比分别为20．3％、14．4％、14．2％、9．4％和7．4％。肠杆菌对氨苄西林的耐药率最高为93．9％,耐药率较低的有亚胺培南、美洛培南、头孢哌酮／舒巴坦和多粘菌素B,它们的耐药率在10．5％～15．9％。非发酵菌对氯霉素、氨苄西林、头孢唑啉和阿莫西林／克拉维酸的耐药率最高在90．1％～100％,对多粘菌素B和头孢哌酮／舒巴坦的耐药率较低,分别为7．7％和16．9％。肠球菌对利奈唑胺、万古霉素、替考拉宁和呋西地酸的耐药率最低,分别为2．6％、7．2％、8．8％和8．8％;葡萄球菌对万古霉素的耐药率为0,对喹奴普汀-达福普汀的耐药率为0．8％,对呋哺妥因、替考拉宁、夫西地酸、利奈唑胺、利福平的耐药率在2．5％～10．7％。结论泌尿系统感染主要病原菌为肠杆菌和肠球菌,由于各病原菌均存在不同程度的耐药性,临床医师应根据尿液细菌培养结果,科学合理使用抗菌药物。     

Resistance to antibiotics in injured coliforms isolated from drinking water

We studied the antibiotic sensitivity of injured coliforms isolated from drinking water of La Plata, Argentina. The antibiotic sensitivity test by the agar diffusion method were proved in: Klebsiella oxytoca (14 strains), Enterobacter aerogenes (4 strains) and Enterobacter cloacae genomic group 3 (14 strains). We found that while these impaired total coliforms were sensitive to piperacillin-tazobactam (TAZ), netilmicin (NTL), ofloxacin (OFLX), and norfloxacin (NFLX) (100%), they had resistant to aminopenicillin-sulbactam (AMS) and nitrofurantoin (NIT) (100%). The resistance to antibiotics demonstrated in these strains would point to the need to promote a rational and judicious use of antimicrobial agents while at the same time implementing a program of active vigilance aimed at ensuring the highest quality of drinking water throughout the system.     

Characteristics of the MRSA clone with reduced susceptibility to vancomycin

The MIC of vancomycin was determined for all S. aureus strains isolated during 1997 in one hospital. MIC values for most isolates were in the range of 0.5-2 mg/l. In 18 strains, MIC was = 6 mg/L. All these strains were MRSA. Recently described VISA strains possessed MIC values for vancomycin equal or higher than 8 mg/l and such strains were not detected in the investigated group. Although strains with MIC = 6 mg/l are not VISA, but they are candidate for reduced vancomycin susceptibility, e.g. during therapy in compromised patients. Analysis of DNA of these strains by pulsed-field gel electrophoresis (PFGE) revealed that 15 of them shared a significant similarity, allowing to place them in the same group. The comparison data of phage patterns as well as antibiotic resistance patterns strongly suggest that all these strains were derivatives of a single clone.     

Marine bacteria: potential sources for compounds to overcome antibiotic resistance

Methicillin-resistant Staphylococcus aureus (MRSA) is the most problematic Gram-positive bacterium in the context of public health due to its resistance against almost all available antibiotics except vancomycin and teicoplanin. Moreover, glycopeptide-resistant S. aureus have been emerging with the increasing use of glycopeptides. Recently, resistant strains against linezolid and daptomycin, which are alternative drugs to treat MRSA infection, have also been reported. Thus, the development of new drugs or alternative therapies is clearly a matter of urgency. In response to the antibiotic resistance, many researchers have studied for alternative antibiotics and therapies. In this review, anti-MRSA substances isolated from marine bacteria, with their potential antibacterial effect against MRSA as potential anti-MRSA agents, are discussed and several strategies for overcoming the antibiotic resistance are also introduced. Our objective was to highlight marine bacteria that have potential to lead in developing novel antibiotics or clinically useful alternative therapeutic treatments.     

Sensitivity to vancomycin and teicoplanin of coagulase-negative staphylococci isolated from clinical specimens

The frequency of resistance and elevated resistance to teicoplanin and vancomycin among 689 strains of coagulase-negative staphylococci isolated in one year from clinical specimens was determined. Using ATB.STAPH test, a resistance was shown mainly among strains of S. epidermidis and S. haemolyticus. The elevated resistance to teicoplanin was much more frequently observed than to vancomycin. About 27% of isolated strains of S. haemolyticus and 6.8% of S. epidermidis were classified as resistant. Among other species only single strains were recognised as resistant: one strain of S. xylosus, one of S. cohni and one of S. intermedius. 94.7% of S. epidermidis and 100% of S. haemolyticus strains classified as resistant to teicoplanin in ATB showed MIC values 14 mg/l. Moreover it was shown that 26.3% of these strains of S. epidermidis and 33.3% of S. haemolyticus had MBC of teicoplanin values equal to or higher than 32 mg/l.     

Antimicrobial susceptibility of microorganisms isolated from urine of pediatric ward patients

The study was an analysis of the frequency of urine bacterial isolation in hospitalized children as well as an evaluation of their susceptibility to antibiotics used in urinary tract infections (UTI). The analysis focused on microbiological urine tests carried out between January 2006 and December 2008. Altogether, 311 strains were obtained, of which E. coli (50.8%) and E. faecalis (13.5%) were the most frequently isolates. The highest percentage of Enterobacteriaceae were sensitive to ceftazidime (92%); to a lesser degree to amoxicillin/clavulanic acid (85%), to trimethoprim/sulfamethoxazole (84%), to nitrofurantoin (82%), to cefuroxime (81%), to cefalotin (66%) whereas only 24% were sensitive to ampicillin. ESBLs were produced by 8% of all Enterobacteriaceae strains. P. aeruginosa strains were totally sensitive to ceftazidime; over 90% - to piperacillin and aminoglycosides, and 77% to carbenicillin. Staphylococci manifested 100% sensitivity to nitrofurantoin. Only 20% of S. aureus were sensitive to trimethoprim/sulfamethoxazole and to trimethoprim; in the case of S. epidermidis: 83% and 67% respectively. No resistant strains were found among S. agalactiae and E. faecalis. E. faecium strains, in turn, were resistant to ampicillin and often to nitrofurantoin (64%), to vancomycin (VanB; 45%) and to high aminoglycoside concentrations (HLAR; 45%).     

Changes of methicillin-resistant Staphylococcus aureus (MRSA) phagotypes in Gdansk in 1990-1998

The aim of the study was the assessment of changes in the occurrence of various MRSA phagotypes in hospitals in the Gdańsk area in 1990-1998. The study was carried out on 175 MRSA strains: 45 strains isolated in 1990-1995 and 130 in 1997-1998. The studied staphylococci were obtained from various clinical materials from patients in 18 hospitals. Phagotyping was done with a set of 10 experimental phages from MRSA strains obtained from the Central Public Health Laboratory in London. Drug-resistance was determined by the disc-diffusion method and in case of strains with medium susceptibility to fusidic acid the minimal inhibitory concentration (MIC) was determined by serial dilutions on solid medium. The study showed among MRSA strains isolated in 1997-1998 a new, previously not known strains with phage pattern MR25/M5 predominated (57.7%). Its presence was found in various hospitals in that area. MRSA belonging to MR25/M5 phagotype were mostly resistant to doxycycline, gentamycin, erythromycin, clindamycin, ciprofloxacin, rifampicin and were resistant or only had medium susceptibility to fusidic acid. The MIC values for strains with medium susceptibility to fusidic acid (4-8 micrograms/ml) showed an evident decrease of the susceptibility to this antibiotic, formerly common in MRSA. At the same time, in 1997-1998 a considerable decrease was observed of the number of MRSA strains belonging to MR8/MR12/MR25/30/33/38/M5/622 phagotype (from 31.1% to 0.8%), and disappearance of strains with phagotypes MR25/56B/M3 and MR8/MR25/622, which in 1990-1995 accounted for 15.6% of the studied staphylococci.