Disappearance of differences in antibiotic resistance of Staphylococcus aureus strains isolated in hospitals and in general practice

There is general opinion that Staphylococcus aureus strains isolated in hospitals are more frequently resistant to antibiotics than community strains, however, the increasing resemblance between hospital and community strains has been recently reported. The aim of the study was to compare the antibiotic resistance and phage-type pattern of S. aureus strains isolated from patients treated either in hospitals or in general practice in northern part of Poland. The study was conducted on 771 S. aureus strains isolated from different specimens. Phage typing was performed according to the method of Blair and Williams. The drug susceptibility was determined by the disc-diffusion method. There were no significant differences in antibiotic resistance or phage-type pattern when hospital and community methicillin-sensitive S. aureus (MSSA) strains were compared. The most MSSA were resistant to penicillin (84.6% and 82.1% respectively) and doxycycline (49.3% and 50.4% respectively) whereas they were rarely resistant to other antibiotics. The predominance of phage group II was found in both hospitals (28.0%) and general practice (29.9%). Phage group III, usually associated with hospitals, occurred in small percentage (12.9% and 9.4% respectively) while to this group predominantly (76.6%) multiresistant methicillin resistant S. aureus (MRSA) isolated in hospitals belonged. These results suggest, that there is only slight difference in antibiotic resistance between hospital and community S. aureus strains. Antibiotic resistance pattern mainly results from frequency of appearance of MRSA, mostly occurring in hospitals.     

Antibiotic resistance and putative origin of Staphylococcus aureus and Klebsiella strains isolated from the children with intestinal dysbacteriosis

The results of the statistical treatment of data on the analyses of 766 children, the residents of Moscow, for dysbacteriosis are presented; of these children, 34 were aged up to 1 month and 732, from 1 month to 1 year. This study revealed that in the fist year of life in children with dysbacteriosis the dominating bacterial species were S. aureus, bacteria of the genus Klebsiella and fungi of the genus Candida. From the intestine of children aged up to 1 month S. aureus and Klebsiella were isolated more often than from children aged up to 1 year. The results of the study of antibioticograms demonstrated that 21.6% of S. aureus strains and 74.4% of Klebsiella strains were multiresistant to antibiotics. Taking into account the fact that multiresistance to antibiotics was characteristic of hospital strains, the suggestion was made that the isolated strains were of hospital origin and such strains could colonize the intestine of children in maternity hospitals.     

Chlorine resistance of strains of Staphylococcus aureus isolated from poultry processing plants

Strains of Staphylococcus aureus which colonize defeathering machinery and become endemic within poultry processing plants appear to be resistant to the normal cleaning and disinfection processes. The resistance of endemic strains to chlorine was compared with that of isolates from the natural skin flora of poultry. Endemic strains were almost eight times more resistant and this was due primarily to their ability to grow in macroclumps but also to the production of an extracellular slime layer.     

Molecular genetic typing of methicillin-resistant Staphylococcus aureus strains, isolated in hospitals of different regions of the Russia and Belarus

The study of the length of the amplification products of the coagulase gene with the subsequent restriction analysis (the method of PCR--restrictive fragment length polymorphism, or RFLP) was used for typing 90 S. aureus strains. Among the strains under study, 78 were methicillin-resistant S. aureus (MRSA) strains, including 74 obtained in 1986 - 2002 in hospitals of different cities of the Russia and Belarus, as well as epidemic strains EMRSA-1, -2, -3, -12, obtained from the National Laboratory of Health, London (UK). The use of this method made it possible to type all the strains under study, which were differentiated into 9 groups by means of endonuclease Sfo1 and 7 groups by means of Alu1. Majority of clinical MRSA strains, belonged, according to the type of restriction, to groups 4 and 5. The study of the coagulase gene by the method of PCR - RFLP made it possible: to analyze the epidemic situation in hospitals for a period of several years; to compare the properties of strains isolated in different hospitals; to establish the genetic relationship of strains, isolated in 1998 - 2002, with strains, isolated in 1986 - 1990. The results of the study suggest that at least two epidemic MRSA strains, genetically similar to international strains, circulate in hospitals of Russia.     

253株金黄色葡萄球菌耐药现状分析

目的 了解医院金黄色葡萄球菌临床分布情况及其对常用抗菌药物的耐药率,为临床合理使用抗菌药物提供依据.方法 回顾分析医院2010年5月至2011年4月检出的金黄色葡萄球菌,采用VITEK-AMS全自动微生物分析仪进行菌种鉴定和药敏分析.结果 共检出金黄色葡萄球菌253株,菌株的主要来源为痰130株(51.4％)、血液39株(15.4％)、创面24株(9.5％);菌株主要科室分布前3位是神内科35株(13.8％)、ICU30( 11.8％)、脑外科26株(10.3％);其中耐甲氧西林金黄色葡萄球菌( MRSA)为165株(65.2％),MRSA对多种抗菌药物耐药率＞70.0％,MSSA为88株(34.8％),对除青霉素、红霉素外的大多数抗菌药物敏感,未发现耐万古霉素菌株.结论 MRSA检出率高,耐药现状严重,应加强对金黄色葡萄球菌耐药性的监测,并根据药敏试验结果合理使用抗菌药物.     

Antibiotic resistance of Lactobacillus strains]

One hundred and thirty six Lactobacillus strains isolated from poultry and 23 Lactobacillus strains isolated from long-living persons were tested for their antibiotic sensitivity. Occurrence of some type determinants of resistance to aminoglycoside antibiotics and tetracyclines in the Lactobacillus strains resistant to these antibiotics was studied. The majority of the strains from the both collections were resistant to aminoglycosides (73 and 79 per cent, respectively). The isolates from the poultry were characterized by multiple resistance. The isolates from the long-living persons were most frequently resistant to one of two antibiotics. All the tested Lactobacillus strains isolated from the long-living persons were sensitive to tetracyclines. The species composition of the isolates was different. The antibiotic-resistant strains were detected in all the species involved in the study. By hybridization of Lactobacillus colonies with the probes containing various genes of the resistance it was shown that in 14 per cent of the antibiotic-resistant strains belonging to Lactobacillus the antibiotic resistance was controlled by the genes homologous to resistance genes widely distributed in gramnegative organisms. This indicated a possible wide exchange and heterologous expression of the antibiotic resistance determinants between microorganisms of various taxonomic groups.     

Drug resistance of Staphylococcus aureus strains, isolated from children with intestinal dysbacteriosis

The level of antibiotic-sensitivity of 73 S. aureus strains isolated from children with dysbacteriosis of the large intestine in an outpatient clinic was determined. The isolation rate of polyresistant strains was 44%. Methicillin-resistant S. aureus (MRSA) were isolated from 25 children (34.2%). 60% of MRSA strains could not be typed with the international set of phages. Among the strains capable of being lyzed by the phages the representatives of phage groups 3 and 4 prevailed. All MRSA strains were sensitive to vancomycin, 84-88% of the strains were sensitive to chloroamphenicol, rifampicin, spiramycin and neomycin, 80% of the strains were sensitive to fusidin and phosphomycin. The level of sensitivity of methicillin-sensitive S. aureus strains (MSSA) to different groups of antistaphylococcal antibiotics was higher. 36-64% of MRSA strains and 21-27% of MSSA strains were resistant to the action of curative bacteriophages. The suppression of obligate microflora was the risk factor in the development of staphylococcal infection of the gastrointestinal tract in children.     

Glycine dependence of Staphylococcus aureus strains]

Glycine dependent Staphylococcus aureus var. bovis strains (TSCHAPE and RISCHE 1971) were tested for their ability to grow on glycine containing and glycine deprived media. We observed glycine dependence only in minimal media. In complete media the strains grew in absence of glycine. Testing the ability of some glycine precursors we found that in minimal media glycine could be replaced by threonine and in some cases by serine. One mutant (Gly 100 Glyox.r.) was able to metabolize glyoxylate instead of glycine. Aspartic acid was metabolized in presence of glycine. Using 14C-aspartic acid we detected 14C-glycine and 14C-threonine. Presumably the bacteria metabolize aspartic acid to glycine via threonine.     

Antiseptic resistance of clinical strains of Staphylococcus aureus

To evaluate the activity of antiseptics and the sensitivity-resistance of bacteria to antiseptics, a number of characteristics has been used, including the minimum inhibiting concentration for different strains, the frequency of statistical and clinical resistance, the antiseptic activity index. A wide spread of S. aureus strains isolated from patients with hospital infections has been revealed. Differences in the resistance of bacterial strains have been established, depending on the type of the antiseptic and the ecovar of bacteria: among hospital ecovars, resistant strains occur more frequently and can resist a wider range of antibiotics. In staphylococcal hospital ecovars the occurrence and level of resistance to a number of widely used antiseptics increase with time. In connection with a wide spread of staphylococcal hospital strains resistant to antiseptics, measures on the control of the circulation of such strains should be introduced into hospitals, and the data thus obtained should be used for the periodic reevaluation of antiseptics used in medical practice and for the choice of preparations to be used for individual therapeutic and prophylactic antisepsis.     

A simplified system for biotyping Staphylococcus aureus strains isolated from different animal species

D evriese , L.A. 1984. A simplified system for biotyping Staphylococcus aureus strains isolated from different animal species. Journal of Applied Bacteriology 56 , 215–220.
A biotyping system for Staphylococcus aureus strains is proposed which is a simplified version of biotyping procedures described in the literature. It differentiates Staph. aureus strains from man and animals into host-specific ecovars and biotypes which are not host-specific. With the help of tests for βhaemolysin, staphylokinase, coagulation of bovine plasma and the crystal-violet reaction, the origin of many but not all Staph. aureus strains can be determined: 604 of 809 strains from man. poultry, cattle, pigs, goats, rabbits and foods could be alloted to four ecovars which are typically associated with man, poultry, sheep and goats and cattle. The other strains belonged to five non-host specific biotypes.     

Clonal analysis of Staphylococcus aureus strains isolated in obstetric-gynaecological hospital

Epidemiological studies were carried out on 135 isolates of Staphylococcus aureus strains originating from medical staff, patients, and hospital environment. Restriction fragment length polymorphism (RFLP) analysis revealed genetic diversity of S. aureus isolates. Some clones were transmitted among nurses, doctors and patients. Our studies also demonstrate contamination of the hospital environment with S. aureus strains and there is a possibility that the patients acquire staphylococci from the environment. Moreover, we found that many medical staff workers were colonized with S. aureus and the transmission of these strains to patients is possible.     

Transferability of antibiotic resistance determinants in strains of Staphylococcus aureus belonging to different phage groups

A total of 107 donor strains of Staphylococcus aureus isolated from clinical material, with a high incidence of multiresistant strains belonging predominantly to phage group III, were tested for transmission of determinants of resistance to 6 antibiotics using mixed cultures of donor strains and the recipient Staphylococcus aureus strain 5849-fur-r, rif-r. The capability of strains to transfer resistance markers to the recipient was found to depend neither on phage group nor phage type to which the donor strain belonged, but strains possessing multiple resistance to antibiotics effectuated transfers at comparatively higher frequencies.     

Immunochemical analysis of a Smith-like antigen isolated from two human strains of Staphylococcus aureus.

A surface antigen consisting of aminoglucuronic acid and N-acetyl-L-alanine was isolated from the culture filtrates of two human strains of Staphylococcus aureus. Double diffusion analysis in agar suggested that the antigen is immunologically similar to the alanyl-aminoglucuronic acid capsule of the Smith strain of S. aureus. Quantitative precipitin inhibition studies indicated that N-acetyl-L-alanine is the immunodominant determinant of the acidic antigen. In addition, conjugates consisting of N-acetyl-L-alanine coupled to bovine serum albumin gave a significant precipitin reaction with anti-staphylococcal serum which is rich in alanyl-aminoglucuronic acid polymer antibodies. Antibodies with N-acetyl-L-alanine specificity were isolated from N-acetyl-L-alanine-Sepharose immunoabsorbent columns. Double diffusion analysis in agar indicated that the eluted antibodies were serologically reactive and belonged to the IgG class of immunoglobulins.     

Genotyping of Staphylococcus aureus strains isolated from healthy persistent carriers

The paper presents results on the relatedness of Staphylococcus aureus strains colonizing the upper respiratory tract isolated from healthy persistent carriers. Genotyping was carried out using two methods—multiple-locus variable-number tandem-repeat fingerprinting (MLVF) and pulsed-field gel electrophoresis (PFGE). By comparison of the results obtained by both methods, good correlations between MLVF and PFGE genotyping of strains isolated from the asymptomatic carriers were observed. Further studies are needed to evaluate methods useful for genotyping of S. aureus strains circulating in the community.     

The characteristic of Staphylococcus aureus strains isolated from food's samples

The study was carried out of 22 isolates of S. aureus isolated from 7 different incriminated food's samples from foodborne-disease outbreaks. The possibility of these isolates to producing of enterotoxins by commercial test SET-RPLA (Oxoid) was tested. The genotyping of these isolates was done by pulse-filed gel electrophoresis, acc. to Pfaller in own modification. On the basis of the DNA restriction patterns of the 22 isolates--5 strains were singled out, one of these strains--strain V (isolat nr 7) was not relationship to others. It was found that this strain V was one enterotoxin produced. Additionaly, all tested strains, in spite of the strain nr V, were isolated from the 2 or 3 samples of different kinds of foods. In the present study it has been shown too, that several similar colonies should be isolated for farther studies to assess microbiological contamination of the food products properly.