烧伤病房患者创面金葡菌分布及耐药性分析

目的分析烧伤病房患者不同创面金葡菌的分布及耐药性,为临床合理选用抗菌药提供依据。方法对2006年1月至2013年12月间中国人民解放军第八五医院烧伤病房患者创面分离出金葡菌,采用K—B纸片扩散法进行药物敏感试验。分析金葡菌的耐药性,并对难愈性创面、非难愈性创面的耐甲氧西林金葡菌（MRSA）与甲氧西林敏感金葡菌（MSSA）的耐药性进行对比分析。结果分离出金葡菌112株,其中难愈性创面有70株MRSA和17株MSSA来自难愈性创面,16株MRSA和9株MSSA来自非难愈性创面。金葡菌对青霉素、红霉素、克林霉素的耐药率较高（分别为94．64％、81．25％和74．11％）,对复方新诺明、呋喃妥因的耐药率较低（分别为16．07％和1．79％）,对万古霉素、利奈唑烷的耐药率为0。MRSA的耐药率高于MSSA。来源于难愈性创面与非难愈性创面的MRSA仅在对利福平的耐药率上有明显差异,而来源于两创面的MSSA的耐药率无明显差异。结论创面金葡菌中MRSA的构成比高,难愈性创面MRSA耐药严重,应积极防控创面MRSA感染和扩散。     

Characterization of Staphylococcus aureus strains involved in human and bovine mastitis

Staphylococcus aureus is one of the main etiological agents of mastitis in different mammalian species. At present, it is unknown whether strains isolated from human mastitis cases share phenotypic properties and genetic background with those obtained from animal mastitis cases. Therefore, the objective of this study was to characterize S. aureus strains isolated from women with lactational mastitis and to compare them with the strains responsible for bovine mastitis and noninfectious strains. All the strains were genotyped by both pulsed field gel electrophoresis and multilocus sequence typing and submitted to a characterization scheme that included diverse assays related to pathogenic potential and antibiotic resistance. Apart from siderophore production, no significant association was observed between the strains from bovine and human mastitis. Statistical differences between human- and bovine-mastitis-associated strains were detected for some traits and virulence determinants, such as the presence of prophages and cna and hlb genes, which were more frequently found within the bovine group. On the contrary, resistance to penicillin was significantly higher among strains isolated from human lactational mastitis, probably related to the common presence of the blaZ gene. A high genetic diversity was found among the strains involved in mastitis in breastfeeding women.     

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.     

Analysis of plasmid profile of antibiotic-resistant Enterobacteriaceae circulating in hospitals

Certain pheno- and genotype properties of S. typhimurium and some other representatives of Enterobacteriaceae resistant to antimicrobial drugs were studied. The strains were isolated from children with salmonellosis within 4 months when an infection hospital was subjected to microbiological observation. It was shown that by their antibiotic resistance, phagovars and molecular weights of the plasmid DNas, the strains S. typhimurium were similar to those isolated during hospital infections. The conjugative plasmids responsible for antibiotic resistance in some strains did not differ in their molecular weights and antibiotic resistance markers. The strains S. typhimurium similar in their pheno- and genotype properties were isolated only from 2 patients which allowed one to consider it possible that the patients were infected by the strains of common genesis. Analysis of nonpathogenic representatives of Enterobacteriaceae isolated from the patients along with the S. typhimurium strains confirmed the fact that the patients were infected with the same pathogenic strain.     

Distribution of citrate utilization plasmids in Salmonella strains of bovine origin in Japan.

Attempts to detect transferable citrate-utilizing (Cit) ability in enterobacterial strains were carried out by conjugation experiments. Of 318 strains of Salmonella typhimurium and 1 strain of Salmonella bredeney isolated from cattle in Japan from 1970 to 1979, 107 (33.5%) strains contained transferable Cit characters. Most of the strains transferred the Cit characters to recipient Escherichia coli more efficiently at 28 degrees C than at 37 degrees C, indicating that their transfer of the Cit character is thermosensitive. Transferred Cit characters were found in association with drug resistance markers such as ampicillin, chloramphenicol, kanamycin, streptomycin, sulfonamides, and tetracycline or with mercury resistance, but Cit plasmids conferring Cit ability alone were also obtained. Of 221 conjugative Cit plasmids tested for fertility inhibition (Fi), all but 2 were Fi- and exhibited thermosensitive transfer; 2 Cit plasmids showing the Fi+ character were also isolated from 2 S. typhimurium strains. No transferable Cit character was detected from strains of Proteus, Serratia, Klebsiella, Enterobacter, and Citrobacter spp. isolated from humans or cows in the present study. The utilization of tricarboxylic acids by strains with plasmid-borne Cit ability was examined, and two different patterns of utilization were found in the Cit+ E. coli transconjugants.     

医院感染葡萄球菌的耐药性及D-试验研究分析

目的了解医院感染葡萄球菌的耐药性及克林霉素诱导试验（D-试验）临床意义。方法从住院患者标本中分离到的539株葡萄球菌进行药敏试验和D-试验,所得结果进行统计分析。结果葡萄球菌中耐甲氧西林金黄色葡萄球菌（MRSA）和耐甲氧西林凝固酶阴性葡萄球菌（MPSE）的检出率高,分别为65．1％和83．6％,各种葡萄球菌对万古霉素敏感率为100％,对阿奠西林头孢菌素在内的各种β-内酰胺酶类抗生素敏感率低于35％,对红霉素耐克林霉素敏感的D-试验阳性率为57．O％。结论葡萄球菌耐甲氧西林检出率,呈多重耐药,在选用大环内酯类,克林霉素类抗生素时要注意D试验,合理用药,提高疗效。     

Multiple antibiotic resistance of Vibrio cholerae serogroup O139 in China from 1993 to 2009

Regarded as an emerging diarrheal micropathogen, Vibrio cholerae serogroup O139 was first identified in 1992 and has become an important cause of cholera epidemics over the last two decades. O139 strains have been continually isolated since O139 cholera appeared in China in 1993, from sporadic cases and dispersed foodborne outbreaks, which are the common epidemic types of O139 cholera in China. Antibiotic resistance profiles of these epidemic strains are required for development of clinical treatments, epidemiological studies and disease control. In this study, a comprehensive investigation of the antibiotic resistance of V. cholerae O139 strains isolated in China from 1993 to 2009 was conducted. The initial O139 isolates were resistant to streptomycin, trimethoprim-sulfamethoxazole and polymyxin B only, while multidrug resistance increased suddenly and became common in strains isolated after 1998. Different resistance profiles were observed in the isolates from different years. In contrast, most V. cholerae O1 strains isolated in the same period were much less resistant to these antibiotics and no obvious multidrug resistance patterns were detected. Most of the non-toxigenic strains isolated from the environment and seafood were resistant to four antibiotics or fewer, although a few multidrug resistant strains were also identified. These toxigenic O139 strains exhibited a high prevalence of the class I integron and the SXT element, which were rare in the non-toxigenic strains. Molecular subtyping of O139 strains showed highly diverse pulsed-field gel electrophoresis patterns, which may correspond to the epidemic state of sporadic cases and small-scale outbreaks and complex resistance patterns. Severe multidrug resistance, even resistance transfers based on mobile antibiotic resistance elements, increases the probability of O139 cholera as a threat to public health. Therefore, continual epidemiological and antibiotic sensitivity surveillance should focus on the occurrence of multidrug resistance and frequent microbial population shifts in O139 strains.     

Drug resistance of opportunistic enterobacteria isolated from various sources]

Resistance of 159 strains of opportunistic enterobacteria to 9 antibacterial drugs was studied. The strains were isolated from man and cattle. It was shown that the overwhelming majority of the isolates (93 per cent) were polyresistant irrespective of the genus. There was a high frequency of the strains resistant to the widely used antibiotics such as chloramphenicol (73 per cent), ampicillin (73.6 per cent) and rifampicin (95.6 per cent) and sulfanilamides (99.3 per cent). Gentamicin and nalidixic acid proved to be the most active against the cultures: 11.9 and 10 per cent of the resistant strains, respectively. The strains of enterobacteria isolated from different sources had a sensitivity to the antibiotics. Multiple antibiotic resistance to at least 5 drugs, variability of the spectra and high resistance were more characteristic of the isolates from the animals. The necessity of a rational use of antibacterial drugs in veterinary is indicated.     

侵袭性和非侵袭性肺炎链球菌耐药率的比较分析

目的研究侵袭性和非侵袭性肺炎链球菌的耐药谱的差异,指导合理应用抗生素及感染管理。方法回顾性统计分析2009至2011年来天台县人民医院就诊患者分离肺炎链球菌的标本来源及耐药性,比较侵袭性和非侵袭性肺炎链球菌耐药率之间的差异。结果共分离出肺炎链球菌642株,痰液中分离出584株,非痰液中分离出58株,其中血液中分离出32株,脑脊液中分离出20株,其他分离出6株,所有肺炎链球菌对万古霉素和利奈唑胺均敏感,对青霉素、红霉素、克林霉素、四环素及复方新诺明耐药严重,对左氧氟沙星、氯霉素比较敏感;侵袭性分离株对青霉素、红霉素、克林霉素、左氧氟沙星、四环素及氯霉素的耐药率显著高于非侵袭性肺炎链球菌。结论该院分离的肺炎链球菌主要来自痰液标本,耐青霉素肺炎链球菌的检出率高,大环内酯类耐药严重,存在一定比例的侵袭性感染,非侵袭菌株与侵袭性菌株耐药谱之间存在一定差异,临床治疗应该区别对待,系统的监测细菌耐药性,合理选择抗菌药物。     

Amikacin resistance of clinical strains of Enterobacteriaceae and Pseudomonas]

Amikacin resistance was studied in 380 bacterial strains of Enterobacter, Klebsiella, Serratia, Pseudomonas and E. coli isolated in clinics of the Moscow Region. It was shown that 69 isolates were resistant to amikacin. Plasmid DNA was detected in 10 amikacin resistant isolates. Three of them belonging to Klebsiella and 3 belonging to E. coli contained plasmids controlling resistance to amikacin. The plasmids isolated from the strains of Klebsiella determined as well resistance to kanamycin and streptomycin but did not control resistance to sisomicin, tobramycin and gentamicin while the plasmids isolated from the strains of E. coli determined resistance to amikacin, kanamycin, gentamicin, tobramycin and sisomicin.     

Transferable drug resistance of Escherichia coli isolated from infant diarrhoea.

The resistance to several drugs was determined in 29 pathogenic strains of Escherichia coli (026, 055 and 0111) isolated from infant diarrhoea and 18 non-pathogenic E. coli strains isolated from the same individuals. Both pathogenic and nonpathogenic strains were resistant to at least 1 to 10 drugs, but only in four cases resistance patterns of the pathogenic strains were identical with those of non pathogenic ones. The majority of the strains were resistant to sulfonamide, tetracycline, ampicillin, carbenicillin, neomycin and kanamycin. The drug resistance (except the resistance to nalidixic acid and rifampicin) was associated with conjugative R-plasmids. Some of the tested strains carried two R-plasmids in one cell, being in hetero R-state.     

Susceptibility to antimicrobial agents of bacteria isolated from pregnant, postpartum women, and newborns from zones with high irradiation risk]

Susceptibility of 350 strains of staphylococci, isolated from pregnant women, puerperal and newborns and of 170 strains, isolated from obstetrical hospital environment at the region with high risk of radiation after accident was determined. The tested bacterial strains were the following: 56--Staphylococcus aureus, 152--S. epidermidis, 142--S. saprophyticus, isolated from women and newborns; strains isolated from hospital environment included 120 strains of S. saprophyticus and 50 strains E. coli. The tested antimicrobial factors were the following: 22 antibiotics, 2 bioantibiotics of the breast milk and blood (lysozyme, betalysin) not separated from the substrate and tested on test-cultures of M. luteus and B. subtilis, and 5 desinfectants. Analysis was performed by common disk-diffusion method and by contact method elaborated before. High resistance of staphylococci to many antibiotics, bioantibiotics and disinfectants was demonstrated. The resistance is considered to be due to high radiation background because it is much higher than resistance frequency of the similar strains isolated at the safe areas. The resistance to antimicrobial factors was higher among the opportunistic and saprophyte staphylococci along with appearance of pathogenic factors and activation of persistence properties.     

香味菌临床分离株耐药谱分析

目的回顾性分析本院临床分离的香味菌的药物敏感情况,指导临床合理使用抗生素。方法收集本院2012年1月至2013年12月期间临床分离的香味菌,采用法国生物梅里埃公司的全自动微生物分析仪VITEK-2进行菌株鉴定,以及VITEK-2配套药敏试验复合板进行药敏检测,分析其耐药谱。结果共收集了8株香味菌,且均呈现多重耐药谱。对头孢菌素类抗生素的耐药率很高,特别是对头孢唑林、头孢他啶、头孢曲松的耐药率均为100%。对氨曲南和呋喃妥因的耐药率均为100%。对碳青霉烯类抗生素亚胺培南的非敏感率达到87.5%。而耐药率最低的左旋氧氟沙星为37.5%。结论本院分离的香味菌呈现多重耐药谱,需对其耐药机制进一步研究。     

新生儿病区产ESBLs大肠埃希菌整合子及其耐药性分析

目的 了解新生儿病区产ESBLs大肠埃希菌整合子的携带情况及其耐药性.方法 采用K-B琼脂扩散法对56株产ESBLs大肠埃希菌进行药敏试验;应用PCR法检测Ⅰ类、Ⅱ类和Ⅲ类整合子;以肠杆菌科重复序列-聚合酶链式反应(ERIC-PCR)进行基因分型.结果 56株产ESBLs大肠埃希菌的Ⅰ类整合子检出率为60.7％,未检出Ⅱ类和Ⅲ类整合子;菌株对庆大霉素、环丙沙星、左氧氟沙星、复方新诺明、头孢唑林、氨曲南、头孢他啶的耐药率差异有统计学意义(P＜0.05),阳性菌株的耐药率高于阴性菌株;56株大肠埃希菌分为45种基因型.结论 Ⅰ类整合子广泛存在于新生儿病区产ESBLs大肠埃希菌并与其耐药性相关.     

Drug Resistance and R Plasmids in Escherichia coli Strains Isolated from Imported Pet Birds

Drug resistance in Escherichia coli strains isolated from pet birds (mynahs, macaws, finches, common bengals, parrots, and flamingos) imported into Japan from 10 foreign countries in 1977 and 1978 was investigated. Of the 309 strains isolated from 127 pet birds in the Animal Quarantine Service, 232 (75.1%) were drug resistant. Furthermore, strains resistant to oxytetracycline hydrochloride, dihydrostreptomycin, and sulfadimethoxine were relatively common. Resistance patterns varied from single to sextuple resistance, and 148 (63.8%) of the resistant strains had conjugative R plasmids. These results suggest that the high incidence of drug resistance and R plasmids in E. coli strains isolated from these pet birds may be a reflection of the prophylactic use of antibiotics for the prevention of diseases which increasingly occur with importation of the birds. Furthermore, the results suggest that the birds may be potential reservoirs of drug-resistant E. coli for families who raise and have intimate contact with such birds.     

Characteristics of hospital strains of Staphylococcus]

Some properties of hospital staphylococcal strains isolated from the patients with purulent postnatal mastitis were studied. It was found that all the strains of the phage type 80.81 widely distributed in the obstetric hospitals were polylysogenic and polyresistant to antibiotics. The resistance markers in most of the isolates were located on the plasmids. Elimination of the plasmids carrying the antibiotics resistance markers resulted in a simultaneous change in the strain lysogenic spectrum while the phage type and fermentative properties, such as production of plasmocoagulase, DNAase and lecithinase did not change. The capacity for hemotoxin production was lost simultaneously with antibiotic resistance in 1 out of 17 cultures tested.     

Sewage dilution and loss of antibiotic resistance and virulence determinants in E. coli

The possession of potential virulence factors (serum resistance, aerobactin production, colicin production) and antibiotic resistance was evaluated in 418 E. coli strains isolated from river water. The strains were isolated from 11 points showing different levels of contamination. From the data obtained, it can be concluded that bacteria from less contaminated water present less antibiotic resistance and virulence factors than those isolated from highly contaminated water. This situation suggests that E. coli strains producing plasmid encoded antibiotic resistance and/or virulence factors, survive less well in aquatic environments without selective pressure) than the sensitive non-virulent ones.     

Staphylococcus cohnii--resident of hospital environment: cell-surface features and resistance to antibiotics

Staphylococcus cohnii strains dominated in the environment of investigated hospitals. We isolated 420 strains of the species mainly from hospitals environments, but also from infants--Intensive Care Units patients, its medical staff and non-hospital environments. S. cohnii subspecies cohnii was seen to dominate (361 strains). Seventy seven percent of these strains expressed cell-surface hydrofobicity, most of them were slime producers (61%) and this feature was correlated with their methicillin resistance. Among S. cohnii ssp. cohnii strains isolated from ICU environment 90% were resistant to methicillin, 43% expressed high-level resistance to mupirocin and high percentages were resistant to many other antibiotics. These strains may constitute a dangerous reservoir of resistance genes in a hospital.     

Assessment of changes in the epidemiology of Clostridium difficile isolated from diarrheal patients in Hungary

150 Clostridium difficile strains isolated from diarrheal feces were collected from three parts of Hungary and the presence of genes responsible for toxin A and B, and binary toxin production were examined. MIC distribution against clindamycin, erythromycin, metronidazole, moxifloxacin and rifampin of 80 toxigenic strains selected from the above-mentioned strains and 20 large clostridial toxins (LCTs)-positive strains chosen from our earlier strain collection were determined. 80% of the examined 150 strains were positive for both tcdA and tcdB, and no toxin A-negative, toxin B-positive isolates were found during the study period. 5.3% of toxigenic strains proved to be positive for binary toxin too. Among binary toxin-positive strains, one strain showed the same pattern characteristic of PCR ribotype 027. Comparison of recent findings and our earlier results, the prevalence of toxin-producing and binary toxin-positive strains among C. difficile isolated from diarrheal specimens increased. No metronidazole resistant isolate was detected among strains isolated in 2002–2003 and 2006–2007. The rates of resistance to erythromycin, clindamycin, moxifloxacin and rifampin among strains isolated between 2006 and 2007 were 25%, 27.5%, 25% and 6.3%, respectively. Erythromycin resistance was frequently associated with clindamycin and moxifloxacin resistance, however this resistant phenotype was not found among strains isolated in 2002–2003.     

Emergence of uropathogenic extended-spectrum beta lactamases-producing Escherichia coli strains in the community

The aim of this study was to determine the virulence characteristics and resistance pattern of the extended-spectrum/lactamases (ESBLs)-producing Escherichia coli strains isolated from urine of outpatients in the Zagreb region during a five-month period, and to compare them with the non ESBLs-producing E. coli strains isolated in the same period. Out of 2451 E. coli strains isolated from urine of nonhospitalized patients with significant bacteriuria, a total of 39 ESBLs-producing strains (1.59%) were detected by a double-disk diffusion technique and by the broth-dilution minimal inhibitory concentration reduction method. The 45 non ESBLs-producing strains were randomly chosen, and phenotype of the two groups of strains was characterized and compared. Serogroup O4, hemolysin production, expression of P- and type 1 fimbriae as well as resistance to gentamicin and amikacin were significantly more prevalent characteristics among the ESBLs-producing strains than among non ESBLs-producing strains (p < 0.01), while higher prevalence of trimethoprim-sulfamethoxazole resistance among ESBLs-producing strains was not statistically significant (p > 0.05). Chromosomal DNA analysis by pulsed-field gel electrophoresis exhibited a great genomic similarity among ESBLs-producing strains and revealed that those highly virulent and resistant E. coli strains isolated from urine of outpatients in the Zagreb region had a clonal propagation.