The adhesion of coagulase negative staphylococci to human skin and its relevance to the bacterial flora of milk

Twenty-eight isolates of coagulase negative staphylococci were obtained from nipple swabs provided by one non-lactating woman and five nursing mothers. All but two of these isolates were shown by scanning electron microscopy to adhere to the surface of human skin. Experiments with frozen sections of human skin confirmed and extended these results by showing that isolates exhibited one of three patterns of adhesion, suggesting that there are three different adhesion receptors on epidermal cells. It is proposed that adhesion of staphylococci to the nipple and areolar epidermis provides a mechanism whereby large numbers of bacteria, nourished by residues of milk and saliva, are maintained on the surface of the skin.     

The adhesion of coagulase negative staphylococci to human skin and its relevance to the bacterial flora of milk

Twenty-eight isolates of coagulase negative staphylococci were obtained from nipple swabs provided by one non-lactating woman and five nursing mothers. All but two of these isolates were shown by scanning electron microscopy to adhere to the surface of human skin. Experiments with frozen sections of human skin confirmed and extended these results by showing that isolates exhibited one of three patterns of adhesion, suggesting that there are three different adhesion receptors on epidermal cells. It is proposed that adhesion of staphylococci to the nipple and areolar epidermis provides a mechanism whereby large numbers of bacteria, nourished by residues of milk and saliva, are maintained on the surface of the skin.     

THE OXIDASE ACTIVITY OF STAPHYLOCOCCI

SUMMARY: By the use of Kovacs'(1956) test, oxidase activity was demonstrated in 23 of 66 strains of coagulase negative staphylococci (or micrococci) but in none of 82 strains of coagulase positive staphylococci. Less sensitive methods showed fewer reactions or failed to demonstrate them at all. Oxidase activity could not be correlated with other biochemical features.     

Coagulase and Deoxyribonuclease Activities of Staphylococci Isolated From Clinical Sources

A total of 504 clinical isolates of the family Micrococcaceae were tested for coagulase, deoxyribonuclease, clumping factor, and phosphatase to determine whether there is a correlation between the results of these tests and the pathogenicity of staphylococci. In the tests for coagulase production, it was found that either human or rabbit plasma could be used with broth cultures, whereas rabbit but not human plasma was satisfactory when microorganisms removed from solid culture medium were used. Deoxyribonuclease production correlated better than the fermentation of mannitol with coagulase production. The use of methyl green, Toluidine Blue O, or acridine orange offered no advantage over the use of HCl for detecting the production of deoxyribonuclease. Neither the presence of clumping factor nor the production of phosphatase correlated well with coagulase production. Strains of staphylococci that did not produce coagulase and deoxyribonuclease were isolated as frequently as, and from a greater variety of clinical sources than, strains which produced these substances. It is concluded that the production of coagulase and deoxyribonuclease are properties of staphylococci which are not necessarily indicative of potential pathogenicity of the organisms for man.     

THE ISOLATION OF COAGULASE POSITIVE STAPHYLOCOCCI FROM ROUTINE COMPOSITE MILK SAMPLES

SUMMARY: Composite morning milk samples were taken once weekly for 9 weeks from 24 dairy farms. In all 208 samples were tested, and coagulase positive staphylococci ( aureus, albus and citreus ) were isolated from 127 (61%). The week by week recovery of these staphylococci from individual farm samples varied between 11% and 88% Penicillin resistant coagulase positive strains were recovered from 20 samples (10%).     

Sensitivity to Lysostaphin as a Criterion for the Identification of Staphylococci from Animal Origin

A total of 195 Gram positive, catalase positive cocci, isolated from ovine mastitis, abscesses in slaughtered animals and parasitic pulmonary lesions in lambs were tested for glucose fermentation, anaerobic growth in thioglycollate medium, coagulase production and susceptibility to the lytic action of lysostaphin. On the basis of lysostaphin sensitivity, 192 strains were classified as staphylococci. The number of cultures able to produce acid anaerobically from glucose, or giving a positive result in the test of Evans and Kloos was lower. A good correlation among these three tests was not observed. Ninety-seven of the strains tested gave a positive coagulase reaction. Sensitivity to lysostaphin could not be used as a criterion for the differentiation of coagulase positive and coagulase negative strains. The turbidimetric method employed for the assessment of lysostaphin sensitivity is discussed.     

Detection of methicillin and mupirocin resistance in staphylococcal hospital isolates with a touchdown multiplex polymerase chain reaction

Staphylococcal hospital isolates (n = 166) were tested in a touchdown multiplex-polymerase chain reaction assay for the identification of methicillin and mupirocin resistance and discrimination of S. aureus (femA gene) from coagulase negative staphylococci and other bacteria. All isolates harbored the 16SrDNA (Staphylococcus genus specific internal control) gene, and 130 (78 %) the mecA (methicillin resistance) gene. Fifty-seven (44 %) of these were determined as methicillin-resistant S. aureus, while the remaining 73 (56 %) were methicillin-resistant coagulase-negative staphylococci. Seventy-five (45 %) isolates harbored the ileS-2 (high-level mupirocin resistance) gene and were determined as mupirocin-resistant. This assay represents a simple, rapid, reliable approach for the detection and discrimination of methicillin-and mupirocin-resistant staphylococci.     

凝固酶阴性葡萄球菌耐药基因和粘附基因检测及耐药性分析

目的了解凝固酶阴性葡萄球菌（CoNS）耐药基因和粘附基因的分布及其耐药性情况。方法收集45株凝固酶阴性葡萄球菌临床分离株,采用PCR检测其耐药基因mecA和粘附基因c弘知如B,并分析其耐药性。结果（1）凝固酶阴性葡萄球菌中mecA、cva、fn6pB的阳性率依次为86．7％（39／45）、11．1％（5／45）、71．1％（32／45）。（2）凝固酶阴性葡萄球菌中耐甲氧西林凝固酶阴性葡萄球菌（MRCoNS）的检出率为88．9％,对β-内酰胺类抗生素的耐药率都在80％以上,对利福平、左氧氟沙星、林可霉素的耐药率较低,未发现对万古霉素、利奈唑胺耐药菌株。结论CoNS中MRCoNS检出率很高,对常用抗生素耐药率高,且有一定的粘附能力,临床上应该根据药敏试验结果慎重及合理的使用抗生素。     

Inhibition of Fibrinogen Reaction by Polysaccharide of Encapsulated Staphylococcus aureus

Encapsulated and nonencapsulated strains of Staphylococcus aureus which lack coagulase or clumping factor (bound coagulase), or both, were examined for the antigen associated with the fibrinogen-cell clumping reaction. Extracts of the cells were tested for the ability to react with fibrinogen or to inhibit fibrinogen precipitation. Antisera prepared against encapsulated (coagulase-positive, clumping factor-negative) variants, as well as against nonencapsulated wild-type (coagulase-positive, clumping factor-positive) S. aureus strains, contained high titers of clumping-inhibiting antibody. When coagulase-negative, clumping factor-negative mutants were the immunizing agents, antisera contained no demonstrable clumping-inhibiting antibody. Phenol extracts of all coagulase-positive strains tested precipitated fibrinogen, regardless of the ability of cells to clump in the presence of fibrinogen. Polysaccharide extracts of encapsulated, clumping factor-negative strains inhibited this fibrinogen-precipitating activity, whereas similar extracts of nonencapsulated staphylococci did not inhibit the fibrinogen reaction. From these results, it appeared that the coagulase-positive, encapsulated staphylococci which do not clump in fibrinogen solution possess clumping factor, but that their capsular polysaccharide inhibits clumping activity. These findings suggested a closer association of clumping factor and coagulase than is now recognized.     

Composition of AME encoding gene in Gram positive Cocci--study on spread of aminoglycoside resistance

Aminoglycoside modifying enzymes (AMEs) are major factors which confer aminoglycoside resistance on bacteria. Composition of six genes encoding AMEs (including lately described aph 2"-genes) was investigated by PCR for 16 clinical isolates of Enterococcus faecalis, 16 clinical isolates of coagulase-positive (S. aureus) and 13 clinical isolates of coagulase negative staphylococci (S. haemolyticus, S. epidermidis) collected in Gdańsk region (Northern Poland) in the years 1998-2001. Diversity of AME encoding gene profiles (composition) was used to analyze spread of AME encoding gene among and within studied group of cocci. According to presence of particular genes we distinguish eleven different AME encoding gene profiles: seven profiles were unique for particular species while the most common was shared among S. aureus, coagulase negative staphylococci and enterococci. Regarding profile frequency statistical analysis (Fstat, AMOVA, cluster analysis UPGMA) shows: the difference between S. aureus and enterococci and coagulase-negative staphylococci, lack of difference between enterococci and coagulase-negative staphylococci, higher variability within than between studied species and presence of multispecies cluster. On the basis of the reports about ability of staphylococci to synthesis enterococcal pheromones, this finding lets assume that spread of aminoglycoside resistance gene among gram (+) cocci is limited only by the ability of stains to synthesis or induction of synthesis conjugation protein.     

Lysozyme Production as an Aid for Identification of Potentially Pathogenic Strains of Staphylococci

Lysozyme production is a frequent property of potentially pathogenic staphylococci. In the present study, 1,186 strains of human origin, 85 strains of animal origin, and 156 strains of Staphylococcus albus (epidermidis) were tested. Of 1,114 coagulase-positive strains of human and animal origin, 1,098 were lysozyme-positive (98.5%). On the other hand, of 157 coagulase-negative strains which, based on further investigations, belong to the potentially pathogenic staphylococci, all were lysozyme-positive. All of the 156 strains (100%) belonging to the species S. albus (epidermidis) were lysozyme-negative. We conclude that lysozyme production is a better index of potentially pathogenic staphylococci than the measurement of free coagulase, especially in cases of strains of animal origin. It is possible that lysozyme production allows a differentiation between pathogenic and nonpathogenic coagulase-negative staphylococci.     

静脉插管相关感染的病原学分析

目的调查静脉插管相关感染的病原微生物分布及其体外药敏试验的情况,为临床诊疗提供依据。方法回顾性分析我院2006年1月至2007年12月期间实施静脉插管的患者发生感染的情况,同时对分离的病原微生物及其耐药性进行分析。结果106例阳性标本中革兰阳性球菌53株（50％）,革兰阴性杆菌33株（31．1％）,真菌16株（15．1％）;革兰阳性球菌中以凝固酶阴性葡萄球菌（31．1％）、金黄色葡萄球菌（11．3％）为主,在葡萄球菌感染中耐苯唑西林金黄色葡萄球菌（MRSA）占75％,耐苯唑西林凝固酶阴性葡萄球菌（MRSCON）占87．9％;革兰阴性杆菌中以鲍曼不动杆菌（9．4％）、铜绿假单胞菌（6．6％）为主;真菌以白色念珠菌（4．7％）及热带念珠菌（3．8％）为主。革兰阳性球菌对万古霉素、利奈唑胺及替考拉宁敏感性高;革兰阴性杆菌较敏感的药物为头孢哌酮／舒巴坦、美罗培南、亚胺培南及阿米卡星,耐药率分别为5％、9．1％、14．8％及15．4％。结论静脉插管相关感染病原微生物以凝固酶阴性葡萄球菌多见,细菌耐药比较严重,应重视抗生素的合理使用。     

Some Physiological Characteristics of Two Sets of Phage-Propagating Strains of Staphylococcus aureus

A number of physiological characteristics were studied on some 29 strains of phage-propagating staphylococci belonging to the Basic International Series and the Seto-Wilson bovine-adapted set. All the cultures except strain 73 were coagulase-positive, with reciprocal titers ranging from 2 to 8,192. Strain 73 was again an exception with respect to phosphatase activity. Group 1 yielded high values for both phosphatase and oxygen uptake but low values for extracellular protein. Resistance to penicillin was demonstrated only by strains 80, 81, 53, 54, 75, and 77. Strain 70, one of the highest coagulase producers, alone showed no catalase activity. Mannitol was fermented by all coagulase-positive strains. Hemolysis of one or more of three kinds of erythrocytes (sheep, rabbit, and human) was a common characteristic of most strains. However, pigmentation was a nondiscriminating parameter. Although one-half of the cultures liquefied gelatin, most of them gave similar antibiotic-sensitivity tests, except the six which were penicillinase producers. There was little difference in growth rate for all strains. Comparison of coagulase production to cell size indicated that the high-titer strains were generally larger than the low producers. The foregoing evidence avers that, in addition to lytic spectrum, physiological properties can usefully characterize staphylococcal phage-propagating strains.     

Investigation of aminoglycoside modifying enzyme genes in methicillin-resistant staphylococci

Methicillin-resistant staphylococci may also be resistant to some other antibiotics as well as beta-lactams. In this study, co-existence of resistance to methicillin and aminoglycosides was genetically investigated in staphylococci. A total of 50 staphylococci from in-patients, 17 Staphylococcus aureus and 33 coagulase negative staphylococci (CNS) that contained mecA (gene encoding PBP 2a, an altered penicillin-binding protein) determined by polymerase chain reaction (PCR) were included in the study. Aminoglycoside modifying enzyme (AME) genes were investigated using multiplex-PCR. Aminocyclitol-6'-acetyltransferase-aminocyclitol-2'-phosphotransferase [aac(6')/aph(2')] gene (encoding bifunctional acetyltransferases/phosphotransferases) was determined in 66% of the isolates, aminocyclitol-4'-adenylytransferase (ant(4')-Ia) gene (encoding phosphotransferases) in 24%, and aminocyclitol-3'-phosphotransferase (aph(3')-IIIa) gene (encoding nucleotidyltransferases) in 8%. Two isolates contained all these three genes. Thirty-six (72%) isolates had at least one of these genes. Three CNS and one S. aureus isolates sensitive to oxacillin had the mecA gene. In conclusion, a high rate of aminoglycoside resistance was determined in methicillin-resistant staphylococci. The aac(6')/aph(2') was the most frequently detected.     

The metabolic heterogeneity of pathogenic and nonpathogenic coagulase negative staphylococci

The coagulase negative staphylococci are a metabolically heterogenous group of strains. The investigated pathogenic and nonpathogenic strains differed markedly in respiration activity and character of endogenous metabolism.     

Etiology of severe hospital infections in intensive care units and antibiotic resistance of pathogens]

The leading pathogens of severe infections in intensive care units were the following: respiratory tract infections--bacteria of the famility of Enterobacteriaceae (33.8%), Pseudomonas spp. (24.9%), Acinetobacter spp. (18.1%), Staphylococcus aureus (16.0%), blood flow infections--coagulase negative staphylococci (33.6%), S. aureus (26.1%), Enterobacteriaceae (17.6%), wound infections--Enterobacteriaceae (35.7%), coagulase negative staphyloccocci (17.8%), Pseudomonas spp. (14.3%). As for various species of Enterobacteriaceae, susceptibility was preserved in 91-100% of the isolates to meropenem, in 72-100% to cefoperazone/sulbactam, in 51-65% to cefepime, in 72-86% to amikacin, and in less than 50% to cephalosporins and fluoroquinolones. As for P.aeruginosa, 28% of the isolates was resistant to all the antibacterials, except polymyxin. The highest susceptibility to cefoperazone/sulbactam and meropenem was revealed in the isolates of Acinetobacter baumannii. Oxacillin resistance was detected in 64.9% of the S.aureus isolates. The oxacillin resistance as a rule was associated with resistance to macrolides, aminoglycosides and fluoroquinolones. As for coagulase negative staphylococci, oxacillin resistance was stated in 75.6% of the isolates. All the isolates of the Staphylococcus spp. preserved their susceptibility to vancomycin and linezolid.     

Biofilm production, a marker of pathogenic potential of colonizing and commensal staphylococci

Biofilm is one of the known virulence factors of staphylococci, a human and animal pathogen and commensal. Some of the strains become invasive under favorable conditions while others do not cause disease. Early detection and management of potentially pathogenic staphylococci is the essential step to prevent device-associated infections. There is also a need to evaluate one simple method for the detection of potential pathogens. Hence this study was planned to study the difference in potential of commensal, colonizing and invasive strains of staphylococci to produce biofilm. We used one qualitative (Congo red agar) and one quantitative (microtiter plate) method for detection of biofilm production and evaluated the sensitivity and specificity of Congo red agar method by using microtiter plate method as a gold standard. We consecutively enrolled staphylococcal strains isolated from peripheral intravenous device (IVD), venous blood, site of IVD insertion and nasal mucosa of patients admitted to pediatric ward with peripheral intravenous devices in place for more than 48 h. Total 100 invasive, 50 colonizing and 50 commensal isolates were studied. Of 100 invasive isolates 74% (74/100) were biofilm positive while only 68% (34/50) colonizing and 32% (16/50) commensal isolates were biofilm positive. The difference in biofilm production by commensal, colonizing and invasive strains was statistically significant (p<0.0001). Sensitivity and specificity of Congo red agar test for detection of biofilm producers were 90.63% and 90.79% for Staphylococcus aureus and 75.86% and 96.88% respectively for coagulase negative staphylococci. CRA is a method that could be used to determine whether an isolate has the potential for biofilm production or not.     

丽水市中心医院2017年临床分离菌耐药情况

目的 了解2017年丽水市中心医院临床分离病原菌的分布情况和耐药特征。方法 收集丽水市中心医院2017年全年临床分离病原菌,采用K-B纸片法及Vitek2-Compact系统进行药物敏感性试验,采用WHONET 5.6软件进行数据分析。结果 共分离到病原菌5 928株,其中革兰阳性菌1 875株（31.63%）,革兰阴性菌4 053株（68.37%）。革兰阳性菌中以金黄色葡萄球菌、凝固酶阴性葡萄球菌、屎肠球菌、粪肠球菌、肺炎链球菌为多见。革兰阴性菌中以大肠埃希菌、肺炎克雷伯菌、鲍曼不动杆菌、铜绿假单胞菌、流感嗜血杆菌为多见。肠杆菌科细菌对碳青霉烯类抗菌药、头孢哌酮/舒巴坦、哌拉西林/他唑巴坦、头孢西丁敏感性较高。产超广谱β内酰胺酶大肠埃希菌和肺炎克雷伯菌的检出率分别为53.5%和23.6%。鲍曼不动杆菌复合群对碳青霉烯类抗菌药、喹诺酮类、头孢吡肟的耐药率>70%。铜绿假单胞菌对阿米卡星、头孢他啶、头孢吡肟、哌拉西林/他唑巴坦的耐药率30%,未检到万古霉素和利奈唑胺的耐药株。耐甲氧西林金黄色葡萄球菌和凝固酶阴性葡萄球菌的检出率分别为43.6%和68.5%。结论 细菌耐药情况日益严重,特别是多重耐药及泛耐药细菌的不断增加给临床治疗带来了极大的困难,因此须定期监测细菌耐药情况以预防耐药菌的产生和传播流行。     

The Tellurite Reactions of Coagulase Negative Staphylococci and Micrococci

S ummary . Methods for determining the tellurite reactions of coagulase negative staphylococci and micrococci have been applied to strains causing urinary tract infections in human patients. The tellurite positive strains were assigned to Micrococcus subgroup 3 and Staphylococcus subgroup VI of the Baird-Parker (1963) classification.     

Nosocomial meningitis caused by Staphylococcus other than S. aureus in children: multicentre study

Analysing 101 cases of nosocomial meningitis due to staphylococci other than S. aureus within last 15 years, coagulase negative staphylococci represented the commonest pathogen. Major risk factor for staphylococcal meningitis was prior neurosurgery, mainly ventriculoperitoneal shunt insertion. Ten of 101 cases were caused by glycopeptide intermediate resistant strains in patients pretreated with multiple combination of antibiotics including vancomycin and shunt exchanges: 76% of strains were also oxacillin resistant.