Phagocytosis of chloramine B sensitive and resistant staphylococci isolated from healthy persons and patients

Phagocytic reaction with respect to antibiotic and chloramine B sensitive and resistant staphylococci isolated from healthy persons and patients, air and stock of medical institutions was studied on albino mice. It was shown that the staphylococcal isolates included strains simultaneously sensitive to antibiotics and chloramine, sensitive to antibiotics and resistant to chloramine, resistant to antibiotics and sensitive to chloramine and simultaneously resistant to antibiotics and chloramine. Activity, intensity and completeness of phagocytosis by leucocytes from mouse abdominal cavity exudates with respect to the staphylococcal strains sensitive to antibiotics and resistant to chloramine, resistant to antibiotics and sensitive to chloramine and simultaneously resistant to antibiotics and chloramine were lower than the values of the phagocytic reaction with respect to the isolates simultaneously sensitive to antibiotics and chloramine. This suggested that not only antibiotic resistance of microbes but also their resistance to disinfectants could be referred to complicating factors of hospital infections.     

Sensitivity to antibiotics and the disinfectant chloramine of Staphylococci isolated from healthy and sick persons

Five hundred and twenty seven strains of Staphylococcus aureus with massive contamination of at least 10(3) when estimated quantitatively were tested for their sensitivity to antibiotics and chloramine B. The staphylococcal strains were isolated from patients, air and stock of rooms in medical institutions, from medical personnel and healthy persons having no long-term contacts with hospital media i. e. from pregnant women and workers of confectionery plants. Among the isolates there were strains simultaneously sensitive to antibiotics and chloramine B (16.6 per cent), sensitive to antibiotics but resistant to chloramine B (5.5 per cent), resistant to antibiotics but sensitive to chloramine B (63.1 per cent) and resistant to antibiotics and chloramine B (15.3 per cent). Staphylococci resistant simultaneously to antibiotics and chloramine B were isolated from the persons of all the groups and from the air and stock of the rooms in the medical institutions. This showed the necessity of controlling sensitivity or staphylococci circulating in hospital media not only to antibiotics but also to disinfectants for providing more efficient prophylaxis of intrahospital infections.     

Biochemical activity of opportunistic antibiotic and chloramine-sensitive and resistant microorganisms isolated from healthy and sick people

Activity of oxidation-reduction enzymes such as succinate dehydrogenase, peroxidase and catalase was studied in staphylococci isolated from healthy persons and patients as well as from the air and implements of medical institutions. The isolates were resistant either to antibiotics or to chloramine B or to the both. The results showed that development of resistance to antibiotics and chloramine B in the staphylococci was accompanied by a decrease in the activity of succinate dehydrogenase, peroxidase and catalase. In the strains resistant only to chloramine B the activity of the enzymes was practically at the same level as in the strains resistant only to antibiotics. In the strains resistant to both antibiotics and chloramine B, the activity of succinate dehydrogenase, peroxidase and catalase did not practically differ from that in the strains resistant either to antibiotics or to chloramine B.     

Chloraminated drinking water does not generate bacterial resistance to antibiotics in Pseudomonas aeruginosa biofilms

Aim: To determine if exposure of Pseudomonas aeruginosa biofilms to chloraminated drinking water can lead to individual bacteria with resistance to antibiotics. Methods and Results: Biofilms of P. aeruginosa PA14 were grown in drinking water in a Kadouri drip‐fed reactor; the biofilms were treated with either 0·5 mg l^‐1 or 1·0 mg l^‐1 of chloramine for 15 or 21 days; control biofilms were grown in water without chloramine. Fewer isolates with antibiotic resistance were obtained from the chloramine‐treated biofilms as compared to the control. Minimum inhibitory concentrations (MIC) for selected antibiotic‐resistant isolates were determined using ciprofloxacin, tobramycin, gentamicin, rifampicin and chloramphenicol. All of the isolates tested had increased resistance over the wildtype to ciprofloxacin, rifampicin and chloramphenicol, but were not resistant to tobramycin or gentamicin. Conclusions: Under these test conditions, there was no detectable increase in antibiotic resistance in P. aeruginosa exposed as biofilms to disinfectant residues in chloraminated drinking water. Significance and Impact of the study: Chloramine in drinking water, while unable to kill biofilm bacteria, does not increase the potential of P. aeruginosa to become resistant to antibiotics.     

Sensitivity of methicillin-resistant Staphylococcus aureus strains to some antibiotics, antiseptics and disinfectants

The effects of antibiotics, antiseptics and disinfectants against some methicillin resistant (MRSA) and methicillin-sensitive (MSSA) Staphylococcus aureus strains have been studied. The MRSA and MSSA strains were equally sensitive to phenols, esters of para(4)-hydroxybenzoit acid and chlorhexidine but MRSA strains were slightly more resistant to quaternary ammonium compounds and considerably more so to dibromopropamidine isothionate. Some MRSA strains were also resistant to phenylmercuric nitrate (but not another organomercurial, thiomersal), mercuric chloride and cadmium chloride. All MRSA strains produced β-lactamase. Strains from the Royal Free Hospital, London were highly resistant to β-lactam antibiotics, erythromycin, trimethoprim and tetracyctines but were sensitive to other antibiotics. One strain from the University Hospital of Wales, Cardiff was resistant to gentamicin but sensitive to tetracycline and trimethoprim.     

Characteristics of gram-negative microflora on environmental objects in puerperal wards and their resistance to antibacterial preparations and disinfectants

The species composition of gram-negative opportunistic bacteria isolated from different objects at three puerperal wards of a maternity clinic was studied. Escherichia coli and Acinetobacter were found to have a fairly wide circulation. The objects most contaminated by these bacteria were determined. The study showed that up to 33.3% of the isolated hospital strains of gram-negative bacteria were characterized by multiple resistance to antibiotics used in medical practice and to sulfathiazole. The strains showed the highest sensitivity to gentamicin and kanamycin. Most of the hospital strains were sensitive to chloramine and nirtan, but 4-13% of Klebsiella and Pseudomonas aeruginosa strains showed enhanced resistance to 0.1% chloramine solution.     

Cadmium resistance in some members of Enterobacteriaceae

Strains of members of Enterobacteriaceae, namely Escherichia coli (18), Klebsiella aerogenes (16), and Serratia marcescens (16) were screened for Cd resistance or sensitivity. Only one strain each of these was resistant to high levels (25 n moles/0.05 ml) CdCl2. The Minimal inhibitory concentration (MIC) of sensitive strains ranged from 0.8-5 micrograms/ml. All the resistant strains were simultaneously resistant to a number of antibiotics. Treatment with sodium dodecyl sulfate eliminated resistance to Cd and to some antibiotics.     

Resistance of different strains of pathogenic staphylococcus to unfavorable environmental factors]

A study was made of the resistance to drying the UV-irradiation, the action of furacillin and chloramine displayed by 60 stains of S. aureus differing by origin (hospital and extrahospital), by the source of discharge (the upper respiratory tracts of carriers and the discharge of the purulent-inflammatory foci of surgical patients), relation to the antibiotics (polyresistant and sensitive) and phage-group reference. It was found that the resistance of staphylococci to the unfavourable factors was not always associated with the listed signs of the strains. In respect to drying a marked resistance was expressed by the hospital strains in comparison with the extrahospital ones, polyresistant in comparison with the sensitive ones, staphylococci of III and I+III phage groups in comparison with the strains of other bacteriophage groups. Strains of the III phage group proved to be the most resistant to the UV-irradiation. Strains isolated from carriers were more resistant to furacillin than staphylococci isolated from the purulent-inflammatory foci. Strains of the III phage group and nontyping had analogous advantages over the cultures of other phage groups.     

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。     

Sensitivity of methicillin-resistant Staphylococcus aureus strains to some antibiotics, antiseptics and disinfectants

The effects of antibiotics, antiseptics and disinfectants against some methicillin-resistant (MRSA) and methicillin-sensitive (MSSA) Staphylococcus aureus strains have been studied. The MRSA and MSSA strains were equally sensitive to phenols, esters of para(4)-hydroxybenzoic acid and chlorhexidine but MRSA strains were slightly more resistant to quaternary ammonium compounds and considerably more so to dibromopropamidine isothionate. Some MRSA strains were also resistant to phenylmercuric nitrate (but not another organomercurial, thiomersal), mercuric chloride and cadmium chloride. All MRSA strains produced beta-lactamase. Strains from the Royal Free Hospital, London were highly resistant to beta-lactam antibiotics, erythromycin, trimethoprim and tetracyclines but were sensitive to other antibiotics. One strain from the University Hospital of Wales, Cardiff was resistant to gentamicin but sensitive to tetracycline and trimethoprim.     

常用微生态制剂的体外药敏试验

目的了解常用微生态制剂与一些常见抗菌药物的体外相互作用。方法从3种微生态制剂(美常安、妈咪爱、培菲康)中培养并分离供试菌,用电子显微镜和药敏纸片做鉴别及药敏试验。结果3种微生态制剂对常用的抗菌药物均敏感。尤其是制剂中的杆菌类对所选的抗菌药物几乎都敏感,而屎肠球菌和粪肠球菌对各种抗菌药物表现出不同程度的耐药。结论除阿莫西林外,常用的抗菌药物不宜与美常安、妈咪爱、培菲康配伍。     

An evaluation of the sensitivity to antiseptic preparations of clinical strains of microorganisms in the family Enterobacteriaceae

Classical enterobacterial strains are sensitive to the working concentrations of pervomur, dioxydine, resorcinol, sodium sulfacyl, iodopyrone, chlorhexidine and boric acid, resistant to the action of cetyplyridinium chloride, rivanol, roccal and ethonium. In enterobacterial populations strains with acquired resistance to chloramine B, iodopyrone, chlorhexidine and resorcinol are present. Hospital strains of enterobacteria are characterized by higher, in comparison with extrahospital strains, resistance to ethonium, sodium sulfacyl, lodopyrone, chloramine B and resorcinol.     

Comparative survival of antibiotic-resistant and -sensitive fecal indicator bacteria in estuarine water.

The survival of antibiotic-resistant and -sensitive strains of Escherichia coli, Enterococcus faecalis, Enterococcus faecium, Streptococcus equinus, and two environmental isolates, AP17 and AQ62, was examined in estuarine water. Each strain was rendered resistant to a combination of two antibiotics by serial passage in increasing concentrations of antibiotics. Cultures were incubated in filter-sterilized estuarine water for up to 7 days. Recovery was assessed by examining colony-forming ability on media with and without antibiotics. None of the antibiotic-resistant forms survived longer than its antibiotic-sensitive counterpart in estuarine water. Three of the resistant strains died off more rapidly than the antibiotic-sensitive wild type. Survival of the test bacteria in estuarine water was as follows: sensitive and resistant AQ62, resistant Escherichia coli less than sensitive Escherichia coli less than resistant AP17 less than resistant Enterococcus faecium less than sensitive AP17, sensitive and resistant S. equinus less than sensitive and resistant Enterococcus faecalis, sensitive Enterococcus faecium. The results supported the suggestion that fecal entercocci may serve as better indicators of fecal pollution than Escherichia coli in marine ecosystems. Moreover, the results indicated that the use of antibiotic-resistant mutants to follow the fate of bacteria in the environment is inappropriate without adequate studies to ensure that resistant and wild-type strains react similarly to environmental stressors.     

28种药物联合氟康唑对白念珠菌体外抑菌作用的初步研究

目的 从常用免疫抑制剂、降血脂药、抗抑郁药、抗生素及非甾体类抗炎药中筛选出可能与氟康唑具有协同增效作用的药物.方法 将5类28种药物配制成相同浓度（100 μg/mL）后分别单独及与低浓度氟康唑联合加入白念珠菌耐药菌株（l00、103）及敏感菌株（sc5314、y0109）菌悬液中,24 h（敏感菌）及48 h（耐药菌）后观察菌液澄清情况,菌液完全澄清为“＋”,混浊为“-”,并重复上述实验3次.结果 舍曲林等7种药物在该浓度下单用即可抑制所有实验菌株生长,与氟康唑合用后抑菌作用更加显著;利福喷丁等6种药物在该浓度下单用只能抑制敏感菌株生长,但与低浓度氟康唑合用后对耐药菌株也有抑制作用.结论 舍曲林、利福喷丁等药物与氟康唑联合后对白念珠菌可能具有协同抑制作用.     

性病后慢性前列腺炎的病原菌及其耐药性研究

目的:探讨本地区性病后慢性前列腺炎的病原菌分布及其对抗生素的耐药性状况.方法:对131例性病后慢性前列腺炎患者的前列腺液细菌培养和药物敏感试验结果进行统计分析.结果:131例性病后慢性前列腺炎患者的前列腺液细菌培养阳性率为86.3%,从113例阳性标本中共分离培养出14种117株细菌,其中以凝固酶阴性表皮葡萄球菌最为常见(45.2%),其构成比显著高于其他病原菌,药物敏感试验结果显示前列腺液分离菌对临床常用的多种抗生素耐药,而对万古霉素、丁胺卡那霉素、呋喃唑酮、多粘菌素B等耐药率相对较低.结论:凝固酶阴性表皮葡萄球菌是性病后慢性前列腺炎的主要病原菌,病原菌检查和药敏试验对临床诊断和治疗性病后慢性前列腺炎具有重要作用.     

Nitrite production by ammonia-oxidizing bacteria mediates chloramine decay and resistance in a mixed-species community

As water distribution centres increasingly switch to using chloramine to disinfect drinking water, it is of paramount importance to determine the interactions of chloramine with potential biological contaminants, such as bacterial biofilms, that are found in these systems. For example, ammonia-oxidizing bacteria (AOB) are known to accelerate the decay of chloramine in drinking water systems, but it is also known that organic compounds can increase the chloramine demand. This study expanded upon our previously published model to compare the decay of chloramine in response to alginate, Pseudomonas aeruginosa, Nitrosomonas europaea and a mixed-species nitrifying culture, exploring the contributions of microbial by-products, heterotrophic bacteria and AOBs to chloramine decay. Furthermore, the contribution of AOBs to biofilm stability during chloramination was investigated. The results demonstrate that the biofilm matrix or extracellular polymeric substances (EPS), represented by alginate in these experiments, as well as high concentrations of dead or inactive cells, can drive chloramine decay rather than any specific biochemical activity of P. aeruginosa cells. Alginate was shown to reduce chloramine concentrations in a dose-dependent manner at an average rate of 0.003 mg l⁻¹ h⁻¹ per mg l⁻¹ of alginate. Additionally, metabolically active AOBs mediated the decay of chloramine, which protected members of mixed-species biofilms from chloramine-mediated disinfection. Under these conditions, nitrite produced by AOBs directly reacted with chloramine to drive its decay. In contrast, biofilms of mixed-species communities that were dominated by heterotrophic bacteria due to either the absence of ammonia, or the addition of nitrification inhibitors and glucose, were highly sensitive to chloramine. These results suggest that mixed-species biofilms are protected by a combination of biofilm matrix-mediated inactivation of chloramine as well as the conversion of ammonia to nitrite through the activity of AOBs present in the community.     

Antibiotic resistance of Salmonella strains isolated from natural polluted waters

Resistance to 14 antibiotics was tested in 270 Salmonella strains isolated from different aquatic environments. All the strains were sensitive to nalidixic acid (30 μg) and cephalothin (30 μg) but more than 90% were resistant to tetracycline (30 μg). The percentage of strains resistant to other antimicrobial substances depended on the antibiotic and on the isolation source. Twenty-four resistance patterns were recorded in strains isolated from three environmental sources. The only multi-resistance detected in the three ecosystems was that of sulphadiazine and tetracycline (about 20%). The serotypes most frequently detected with multi-resistance to different antibiotics were Salmonella typhimurium and Salm. blockley.     

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.     

Fecal coliforms of wastewater treatment plants: antibiotic resistance, survival on surfaces and inhibition by sodium chloride and ascorbic acid.

Three hundred and sixteen fecal coliform strains isolated from raw sewage and final effluents of two representative wastewater treatment plants were examined for antibiotic resistance. For plant A (which was disinfecting its effluents before discharge), 55% and 41% of the strains isolated from the influent and the effluent, respectively were resistant to one or more antibiotics. For plant B (which was not disinfecting its effluents before discharge), 33% and 58% of the strains isolated from the influent and the effluent, respectively were resistant to one or more antibiotics. A considerable proportion of these bacteria were resistant to three or more antibiotics. NaCl (3%) and ascorbic acid (0.1%) reduced the growth rate of both sensitive and resistant strains, and more inhibitory effects on the sensitive strains than on the resistant strains were observed. All resistant strains tested survived on various types of surfaces (e.g. glass, stainless steel, agar, cabbage, parsley and sand) significantly better than sensitive strains.     

Ribosomes from spiramycin resistant mutants of Escherichia coli Q13

Summary Mutants from Escherichia coli Q13 were selected for resistance to leucomycin, tylosin or spiramycin. Most of the mutants so selected exhibited cross resistance to all the macrolide antibiotics tested including erythromycin. A few mutants however seem to be less resistant to erythromycin. One mutant, QSP008, was highly resistant to tylosin, leucomycin and spiramycin but relatively sensitive to erythromycin. Another mutant, QSP006, was highly resistant to spiramycin but less resistant to erythromycin, tylosin and leucomycin. This selective resistance of cells to specific antibiotics could be due to the extent of conformational alteration of their ribosomes, which may be demonstrated by the extent of ¹⁴C-erythromycin binding to these ribosomes. The ribosomes from QSP008 cells were found to contain an altered 50-8 protein of the 50s ribosomal subunit, while in the ribosomes from QSP006 no such protein change could be detected by the methods used.A preliminary data of part of this work has been published (Tanaka, Teraoka, Tamaki, Watanabe, Osawa, Otaka, and Takata, 1971).