Nanoparticles Production and Inclusion in <i>S. aureus</i>Incubated with Polyurethane: An Electron Microscopy Analysis

This study shows that submicron/nanoparticles found in bacterial cells (S. aureus) incubated with polyurethane (a material commonly used for prostheses in odontostomatology) are a consequence of biodestruction. The presence of polyurethane nanoparticles into bacterial vesicles suggests that the internalization process occurs through endocytosis. TEM and FIB/SEM are a suitable set of correlated instruments and techniques for this multi facet investigation: polyurethane particles influence the properties of S. aureus from the morpho-functional standpoint that may have undesirable effects on the human body. S. aureus and C. albicans are symbiotic microorganisms;it was observed that C. albicans has a similar interaction with polyurethane and an increment of the biodestruction capacity is expected by its mutual work with S. aureus.

Low-Level Antibiotic Resistance among Staphylococcus aureus and Gram-Negative Pathogens from Infected Skin and Soft Tissues in Rural Kenya

Introduction: Bacterial skin and soft tissue infections (SSTIs) are a cause of frequent inpatient and outpatient care visits whose causative agents are associated with a high antimicrobial resistance burden. For insights on antimicrobial susceptibilities in a rural setting, we examined specimens from suspected SSTIs from two public health facilities in Kenya. We additionally assessed antibiotic use, appropriateness of empiric therapy and risk factors for SSTI. Methodology: Between 2021 and 2023, 265 patients at Kisii and Nyamira County Referral hospitals were enrolled. Wound swabs/aspirates were collected and processed following standard microbiological procedures. Identification and antimicrobial susceptibility were performed using the VITEK 2 Compact platform. Demographic, clinical, and microbiological data were analyzed with R Statistical software. Results: S. aureus was isolated in 16.2% (43/265) of patients with a methicillin resistance (MRSA) proportion of 14% (6/43). While 13/15 drugs elicited susceptibilities ranging from 84% - 100%, penicillin (16%) and trimethoprim-sulfamethoxazole [TMP-SXT] (23%) yielded the lowest susceptibilities. Escherichia coli (n = 33), Klebsiella pneumoniae (n = 8), Pseudomonas aeruginosa (n = 8), and Citrobacter species (n = 4) were the most commonly isolated gram-negative species. Gram-negative strains showed high susceptibilities to most of the tested drugs (71% - 100%) with the exception of ampicillin (18%), TMP-SXT (33%), and first and second generation cephalosporins. Conclusions: The low MRSA prevalence and generally high antibiotic susceptibilities for S. aureus and gram-negative bacteria present opportunities for antibiotic stewardship in the study setting. Diminished susceptibilities against penicillin/ampicillin and TMP-SXT accord with prevailing local data and add a layer of evidence for their cautious empiric use.

Electrochemical Biosensor for Detection of Staphylococcus aureus Based on Nucleic Acid Aptamers

Staphylococcus aureus is a gram-staining positive cocci bacillus baterium and also one of the foodborne pathogens, which is a serious potential hazard to human health and food safety. We constructed an electrochemical biosensor for the detection of S. aureus based on nucleic acid aptamers to achieve highly specific detection of S. aureus. The detection of S. aureus was realized by using Aptamer (Apt) to capture S. aureus, which resulted in a change in the spatial conformation of Apt and a decrease in the electrochemical signal. Under the optimized experimental conditions, the detected electrochemical signals were positively correlated with the concentration of S. aureus with a linear range of 1 × 101 - 1 × 105 CFU/mL, a detection limit of 4.76 CFU/mL, and an experimental recovery of 97.43% - 99.37%. Therefore, we successfully constructed an electrochemical biosensor for the specific detection of S. aureus, which has the advantages of high specificity, sensitive detection and convenient operation.

Molecular Diversity of <i>Staphylococcus aureus</i>from the Nares of Hospital Personnel, HIV-Positive and Diabetes Mellitus Patients in Yaounde Cameroon

Nasal carriage of Staphylococcus aureus has been identified as a risk factor for the development of staphylococcal infections caused by endogenous colonizing strains. Information on the genotypic diversity of Staphylococcus aureus is relevant for managing epidemiological and clinical challenges resulting from the evolutionary differences of this bacterium. The objective of this study was to determine and compare the molecular diversity of Staphylococcus aureus isolates from three high-risk populations in Yaounde, Cameroon. Molecular analysis confirmed that 95% of 100 tested isolates were S. aureus. The mecA and Panton Valentine-Leukocidin (PVL) genes (lukS/F-PV) were detected in 37% (35/95) and 43% (41/95) of isolates respectively and 18% (17/95) of the isolates harboured both the mecA and lukS/F-PV genes. A mixed distribution of both methicillin sensitive S. aureus (MSSA)/PVL and methicillin resistant S. aureus (MRSA)/PVL strains were detected within the study population. Community associated MRSA accounted for 94% (33/35) of the isolates, further classified into allotypes SCCmec type IV 54% (19/35) and SCCmec type V 40% (14/35), while two isolates were hospital associated SCCmec type II strains. A majority of the isolates harboured a single aggressive gene regulator allele agr type I. Pulsed Field Gel Electrophoresis (PFGE) generated 18 pulsotypes that grouped isolates irrespective of the study population. Multilocus Sequence Typing (MLST) of 12 selected isolates was assigned to six pandemic clonal complexes (CC): CC5 (ST5), CC8 [ST8, (n = 3)], CC15 (ST 15), CC25 (ST 25), CC72 [ST72 (n = 2)] and CC121 [ST 121 (n = 2)] and three atypical sequence types ST 508, ST 699 (CC45) and ST 1289 (CC 88). The study population represents an important reservoir for MRSA, MRSA-PVL and MSSA-PVL which could serve as focal point for further dissemination bringing about significant clinical and epidemiological implications. The predominance of SCCmec IV and agr types in this setting warrants further investigation. Isolates were genetically diverse with MLST indicating that pandemic ST8 was predominant. Detection of atypical STs has provided an insight into the necessity for constant monitoring.

低温等离子体杀灭橙汁S.aureus的研究

非热杀菌能更好地提供产品质量,保留较好的营养成分,比传统杀菌技术更能节省能源,为开拓新的市场创造更大机遇。利用自行设计的介质阻挡放电反应器(DBDR),以鲜榨果汁为杀菌介质,研究DBDR所产生的低温等离子体(LTP)对鲜榨果汁的金黄色葡萄球菌(S.aureus)的杀菌规律。选取循环次数、pH、温度和电压4个因素进行中心组合设计,利用响应面对其杀菌规律进行研究,建立了低温等离子体(LTP)杀灭橙汁中S.aureus的二次多项数学模型,验证了模型的有效性,利用DesignExpert软件对其进行分析表明:循环7次,pH2.5,温度50℃,电压25kV时,杀菌率log(N0/N)最大,其预测值为5.19,与实测值相符。

Development of a Multiplex PCR for Diagnosis of Staphylococcus aureus, Escherichia coli and Bacillus cereus from Cows with Endometritis

Staphylococcus aureus, Escherichia coli and Bacillus cereus are the major agents of cow endometritis in dairy cows. A multiplex PCR （SEB-mPCR） was established based on the conserved genes of S. aureus, E. coli and B. cereus, and the detection limits were 103, 102 and 103 CFU mL-1, respectively. SEB-mPCR could not amplify genomic DNA of pathogenic bacteria of other common bovine diseases. A total of 309 vaginal discharge samples from cows with endometritis were tested by SEB-mPCR. Of the samples, 23.95% had the three kinds of bacteria detected, 17.15% had S. aureu and E. coli, 9.39% had E. coli and B. cereus, and 9.71% had S. aureus and B. cereus. The rates of infections with S. aureus, E. coli and B. cereus were 11.35, 16.18 and 9.06%, respectively. Therefore, SEB-mPCR has a potential as a diagnosis tool for endometritis in dairy cows.

Studies on Enterotoxins and Antimicrobial Resistance in Staphylococcus aureus Isolated from Various Sources

Staphylococcus aureus represents a public health challenge all over the world. Therefore, this study aims to analyze the prevalence of five genes (sea, seb, sec, see and seg) encoding the staphylococcal enterotoxins in S. aureus isolated from different sources and to evaluate the association of these toxins in comparison to susceptibility towards 12 antimicrobials;antimicrobial susceptibility was conducted by disc diffusion method. Detection of staphylococcal enterotoxins was performed by PCR and the ability to express these genes was assessed among isolates by RT-PCR. The most common enterotoxin gene was sea gene (66%), followed by seb, sec, see and seg (38%, 23%, 19% and 5%) respectively. Expression of sea, seb and seg genes was variable. However, sec and see genes were not expressed by any of the tested isolates. No statistically significant association exists between (seb, sec and see) and isolation sources, while the sea was significantly associated with clinical isolates. High significant correlation was found between elevated sea expression and multidrug-resistance. Our findings indicate that the pathogenic potential of S. aureus may be greater than previously thought. This emphasizes the utmost need to implement proactive measures and more emphasis will be placed on the application of hygiene practices in hospitals to control S. aureus infection and enterotoxins production.

Effect of Nano - Titanium Dioxide with Different Antibiotics against Methicillin-Resistant Staphylococcus Aureus

The different investigation has been carried out on the biological activities of titanium dioxide nanoparticle but the effect of this nano product on the antibacterial activity of different antibiotics has not been yet demonstrated. In this study the nano size TiO2 is synthesized using citric acid and alpha dextrose and the enhancement effect of TiO2 nanoparticle on the antibacterial activity of different antibiotics was evaluated against Methicillin-resistant Staphylococcus aureus (MRSA). During the present study, different concentrations of nano-scale TiO2 were tested to find out the best concentration that can have the most effective antibacterial property against the MRSA culture. Disk diffusion method was used to determine the antibacterial activity of these antibiotics in the absence and presence of sub inhibitory concentration of TiO2 nano particle. A clinical isolate of MRSA, isolated from Intensive Care Unit (ICU) was used as test strain. In the presence of sub-inhibitory concentration of TiO2 nanoparticle (20 μg/disc) the antibacterial activities of all antibiotics have been increased against test strain with minimum 2 mm to maximum 10mm. The highest increase in inhibitory zone for MRSA was observed against pencillin G and amikacin (each 10 mm). Conversely, in case of nalidixic acid, TiO2 nanoparticle showed a Synergic effect on the antibacterial activity of this antibiotic against test strain. These results signify that the TiO2 nanoparticle potentate the antimicrobial action of beta lactums, cephalosporins, aminoglycosides, glycopeptides, macrolids and lincosamides, tetracycline a possible utilization of nano compound in combination effect against MRSA.

Menaquinone (Vitamin K2) Enhancement of <i>Staphylococcus aureus</i>Biofilm Formation

During infection, Staphylococcus aureus is exposed to exogenous menaquinone which is essential for the human blood clotting cascade. The effect of exogenous menaquinone on S. aureus phenotypic expression is not known. To test whether menaquinone affects expression of virulence-associated phenotypes, methicillin-sensitive (MSSA) and -resistant (MRSA) S. aureus strains (n = 8) were grown in the presence of menaquinone (0.001 - 12 μg/ml). Capsule production, biofilm formation (plastic and fibronectin-coated microtiter plates) and carotenoid levels were determined spectrophotometrically after growth in Mueller Hinton broth (MH;24-hr, 37°C). All experiments were, at minimum, done in triplicate and repeated twice. Menaquinone at physiologic levels (0.01 μg/ml MH) significantly increased (p 0.05) biofilm formation on plastic in a manner that was bacterial population size dependent. In addition, menaquinone (0.05 - 4 μg/ml) significantly increased (p 0.05) biofilm formation on fibronectin-coated surfaces for four MSSA strains and one MRSA strain by two to six-fold as compared to medium controls. However, menaquinone had no effect on capsule production or cell-associated carotenoid levels. Menaquinone’s effect on biofilm formation on fibronectin-coated surfaces appears to be regulated by sarA. These findings are the first to demonstrate that a vitamin at concentrations reported in humans affects S. aureus virulence-associated phenotypes.

<i>Staphylococcus aureus</i>Can Produce Catalase Enzyme When Adding to Human WBCs as a Source of H₂O₂Productions in Human Plasma or Serum in the Laboratory

Background: Staphylococcus aureus is one of the most virulent gram positive bacteria. It produces a lot of toxins and enzymes, most of which are virulent factors. Among the enzyme that produces is the catalase which is very useful in differentiating staphylococci from streptococci [1]. Catalase is nearly ubiquitous among some of organisms that can grow in the presence of oxygen (air). It promotes the conversion of hydrogen peroxide, a powerful and potentially harmful oxidizing agent, to water and molecular oxygen;so the major function of catalase within cells is to prevent the accumulation of toxic levels of hydrogen peroxide formed as a by-product of metabolic processes—primarily that of the electron transport pathway. Objectives: The main aim of this study is to prove that human WBCs can produce H2O2. This H2O2 when reacting with catalase producing S. aureus can easily be degraded to H2O + O2. Methodology: In this study a total of 40 subjects were included. Aliquots of 2.5 ml of venous blood were collected by venous puncture after disinfecting the site of collection with 70% alcohol and the collected blood was drawn into EDITA containers (20 subject) and anticoagulant free containers (other 20 subject), centrifugation for 5 minute at 1500 RPM. The separated sera and plasma were converted to new sterile eppendrof tubes and freezing until used (we leaved the eppendrof tubes that contained sera and plasma at room temperature before using it for DE freezing). Standard catalase producing S. aureus were used by taking 1 colony from Macconkey media by using applicator wooden stick, and inserted in eppendrof tube, then air bubbles would appear to indicate occurrence of the reactions. Results: According to this study, it was proved that WBCs in human plasma or serum can produce H2O2;this H2O2 was reacted with catalase enzyme produce from colony of S. aureus to produce air bubbles and water. There were no differences between using H2O2 or human plasma/serum that contains WBCs to detect and identify S. aureus by both techniques. Conclusion: Based on the results of this study, we can use WBCs that are found in human plasma or serum to identify catalase producing S. aureus.

A Review of <i>Staphylococcus aureus</i>and the Emergence of Drug-Resistant Problem

There are various bacteria living in this world. The most common one is Staphylococcus aureus. Almost everyone has heard of it. It is easy to find their habitats, such as hospitals, homes, parks, schools etc. Some of them are difficult to be eliminated because of drug-resistant mutations. Hence, lots of researchers devoted their efforts to eliminate them. This review illustrates the characteristics of the Staphylococcus aureus and the main threat of their drug-resistant strains, especially methicillin-resistant S. aureus. What’s more, the article also highlights the plight in the drug development.

Quantitative Adhesion of <i>Staphylococcus aureus</i>on Stainless Steel Coated with Milk

The surface energy characteristics of uncoated (clean) and coated stainless steel with UHT milk at various contact time (5 min, 30 min, 1 hours, 3 hours, 6 hours, 24 hours) were determined using contact angle measurement. Whatever the contact time, the clean stainless steel coupons became more hydrophobic and more electron acceptor when they are coated by milk. Inversely, the electron donor character seems to decreasing in this condition. The calculated surface energy component of coated stainless steel was found to vary with contact time. Its hydrophobicity and its electron acceptor were minimal after 3 hours of contact, but its electron donor was minimal after 1 hours of contact. Adhesion experiments of Staphylococcus aureus were carried out on uncoated and coated stainless steels at various contact times. For all contact times, the adhesion results show that milk reduce S. aureus adhesion, and the level of this reduction depend on contact time. This reduction was lower and higher after 1 hours, 5 min and 30 min of contact respectively.

Development of a Duplex Real-Time PCR Method for the Pharmaceutical Rapid Microbial Detection of <i>Staphylococcus aureus</i>and <i>Pseudomonas aeruginosa</i>

Objective: To develop a duplex real-time PCR assay for pharmaceutical rapid microbial detection of Staphylococcus aureus and Pseudomonas aeruginosa. Methods: The specific primers and probes were designed to amplify the femB gene of S. aureus and the DNA gyrase subunit B gene of P. aeruginosa. The sensitivity of the system was detected by a multiple proportional dilution method. In order to examine the specificity of the system, other twenty-one bacteria strains were assayed simultaneously. Results: A highly sensitive and specific duplex real-time PCR assay for the detection of S. aureus and P. aeruginosa was established. The sensitivity was 50 copies/μL. The specificity was 100%. The whole detection procedure can be finished within 2.5 h. Conclusion: The duplex real-time PCR method is efficient in detecting with good sensitivity and specificity. There is a good prospect of this method applying in disease prevention and pharmaceutical industry due to the simultaneous detection of two pathogens.

Comparative Study of Three β Lactamase Test Methods in <i>Staphylococcus</i>aureus Isolated from Two Nepalese Hospitals

Background: β lactamase is a plasmid-encoded enzyme that hydrolyzes β lactam ring of β lactam antibiotics rendering them ineffective. These enzymes, produced by Staphylococcus aureus along with many other organisms, have hindered the use of many useful and once life-saving β lactam antibiotics from clinical practice. Methods: This study was aimed to compare three test methods-chromogenic, acidimetric and iodometric-for the detection of β lactamase enzyme produced by 404 nosocomial induced S. aureus isolated from two Nepali hospitals, Kathmandu based hospital (KBH) and Lalitpur based Hospital (LBH). The study was carried out following standard methodology during November 2007 to June 2009 in the Department of Microbiology, Institute of Medicine, Kathmandu, Nepal. Sensitivity, specificity, efficiency, positive predictive value, and negative predictive values of the tests were calculated taking penicillin resistance and sensitivity as the standard. Results: Chromogenic method was found to be the most sensitive (98.93%) and efficient (98.51%) test and had a high positive predictive value (99.46%). Sensitivity (98.4%) and efficiency (98.27%) of iodometric method was found to be comparable to chromogenic test;its specificity (96.55 %) and positive predictive value (99.73%) were the highest among the 3 tests. Acidimetric test was the least sensitive (97.33%) and efficient (96.78%). Of note, the sensitivity and specificity of these test methods have been compromised due to the negativity of few penicillin resistant isolates and positivity of some penicillin sensitive isolates, respectively. Conclusion: Chromogenic method was found comparatively to be the best test method for the detection of β lactamase production. However, in contrast to the other two test methods whose reagents can be locally and economically prepared, chromogenic test’s use has been impeded by its cost and unavailability in the local Nepali market.

Heterogeneity in <i>femA</i>in the Indian Isolates of <i>Staphylococcus aureus</i>Limits Its Usefulness as a Species Specific Marker

Increase in prevalence of MRSA worldwide and hence the need for rapid detection, have led to use of molecular methods for confirmation of the species and also MRSA. Species specific markers like fem or nuc along with the methicillin-resistance determinant, mecA, have been used by several investigators worldwide for the identification of MRSA. In the current study, we have screened 54 microbiologically confirmed (MRSA, MSSA and CoNS) isolates for the presence of mecA, 16S rRNA, femA and nuc markers. While mecAPCR and 16S rRNAPCR results were consistent with other studies, femA and nuc showed dramatic variation in detection rate (sensitivity) of S. aureus 29.6% and 53.7% respectively. Evidences are presented to demonstrate the absence of femA. Our attempt to amplify the complete femA gene using sequences flanking femA further confirmed these results and also indicated that variations exist even in the genomic sequences around femA. Our data reveals the need for exercising care while using primers designed on sequences of constitutive genes like femA and nuc for PCR based identification of S. aureus species. Though geographic variations in the genome of S. aureus have previously been reported from around the world, we present here evidence for the first time from India for absence of femA and also for probable variations in the sequences around the femA gene in clinical isolates of S. aureus.

Prevalence of Panton Valentine Leukocidin in Carriage and Infective Strains of <i>Staphylococcus aureus</i>at a Referral Hospital in Kenya

Panton valentine leukocidin (PVL) is a pore forming exotoxin that is expressed by some Staphylococcus aureus (S. aureus) strains and is thought to add to its virulence. The prevalence of PVL in carriage and disease causing strains varies considerably from region to region. This study compared the prevalence of the PVL gene in S. aureus isolates obtained from healthcare workers and from patients seen at the Aga Khan University Hospital Nairobi (AKUHN). S. aureus isolates obtained from healthcare workers and patients attended to at AKUHN between July 2010 and March 2011 were used for this study. Forty five S. aureus isolates from healthcare workers and 63 from clinical specimens obtained from 59 patients were analysed for the PVL gene. The prevalence of PVL in isolates from healthcare workers was 24.4% compared to 39.7% in the isolates causing infection (P = 0.098). PVL prevalence was 58.8% in S. aureus isolates obtained from skin and soft tissue infections (SSIs) compared to 25.0% in carriage isolates (P = 0.002, OR 4.29). Prevalence in isolates from invasive infections was 11.1%. Patients with PVL positive S. aureus were younger than those with PVL negative isolates (P = 0.082). The high prevalence of PVL is comparable with that reported in other African countries. The significance of the high prevalence of PVL in S.aureus isolates carried by health care workers at AKUHN is unclear at the moment. PVL prevalence is significantly higher in S. aureus isolates causing SSIs compared to carriage and invasive isolates.

Reduction of Beta-Lactam Antimicrobial Activity in <i>Staphylococcus aureus</i>Abscesses by Neutrophil Alteration of Penicillin-Binding Protein 2

We previously demonstrated that brief nonkilling neutrophil exposure diminishes the binding affinity of S. aureus penicillin-binding protein (PBP) 2. We sought to investigate further the role of the neutrophil in the alteration of antimicrobial activity and its interaction with PBP-2 by studying the activity of cefotaxime, which highly binds to PBP 2, and cephalexin, which minimally binds to PBP 2. Using S. aureus, cultured in vitro in sterile-filtered normal and neutrophil depleted abscess fluid, we sought to demonstrate an in vivo significance of the neutrophil effect upon the activity of antimicrobials that target PBP-2 by studying the same antimicrobials in an experimental S. aureus abscess. Rats were implanted with perforated tissue cages and infected with S. aureus;some rats were neutrophil depleted by mechlorethamine. Abscess fluids from normal and neutropenic abscesses were harvested, pooled, sterile-filtered and stored for the time-kill studies. Treatment studies were performed by administering either 300 μg/kg/d cefotaxime or cephalexin for 7 days in other rats with 24 hour-old tissue-cage S. aureus abscesses. In time-kill studies, cefotaxime was highly active against stationary phase S. aureus in MHB and in neutropenic abscess fluid, but less active in the non-neutropenic abscess fluid (p 10 kill, p = 0.029 vs. 0.81 ± 2.5, p = NS). These data suggest that neutrophil exposure, which diminishes S. aureus PBP-2 binding affinity [or total quantity], also adversely affects the antimicrobial activity of cefotaxime, which binds to PBP-2, as compared to cephalexin. Altered PBP targets from neutrophil exposure may be a mechanism of antimicrobial resistance within abscesses.

Effect of Ethanol Extract of Venenum Bufonis on Biofilm Formation of <i>Staphylococcus aureus</i>

Ethanol extract of Venenum Bufonis has shown many valuable bioactivities, but little is known about its effect on biofilm formation of Staphylococcus aureus. In this study, biofilm formation of S. aureus NCTC8325 with or without ethanol extract of Venenum Bufonis was tested using microtitre plate assay and Confocal Laser Scanning Microscope (CLSM) system. Results show that the biofilm formation of S. aureus with ethanol extract of Venenum Bufonis was significantly lower than that of the control group without ethanol extract of Venenum Bufonis. Meanwhile, the reduction degree was correlated to the concentration of ethanol extract of Venenum Bufonis positively. With CLSM system we can observe that looser and less biomass of the biofilm structure of the experimental group appeared than that of the control group. These results suggested that ethanol extract of Venenum Bufonis has inhibitory effect on biofilm formation of S. aureus.

Neutrophilia-Inducing Deferoxamine in Mice Infected with <i>Staphylococcus aureus</i>

The ability to sequester iron is a primary defense mechanism against bacterial infection. Iron chelation therapy has been considered as a possible treatment for various infectious diseases. S. aureus isolated from neonatal septicemia were used to study the effect of deferoxamine and sub-minimal inhibitory concentration of gentamicine on some virulence factors of this isolates. Also an experimental sepsis was inducted in mice and treated with gentamicin and deferoxamine. The expression of virulence factor (alpha-hemolysin, beta-hemolysin, delta-hemolysin, coagulase, and DNase) by Staphylococcus?aureus isolates was significantly decreased (p < 0.05) after exposure to DFO and/or gentamicin. The data of the present study showed that using of DFO led to significant decrease (p < 0.05) in the mortality rate of mice infected with S. aureus. In a murine model of S. aureus sepsis, deferoxamine treatment had an additional effect on survival and bacterial eradication from the organs of septicemic mice. In vitro exposure of S. aureus isolated to gentamicin and deferoxamine led to a decrease in the production of some virulence factors by these isolates.

中国制霉菌素产生菌金色链丝菌S. aureus A94 S-7菌株在制霉菌素发酵滤液中微量抗细菌活性成分的初步探索

长期以来普遍认为中国制霉菌素产生菌不产生抗细菌物质,本文探讨该菌于制霉菌素发酵时产生的抗细菌活性组成,作为进一步研究其应用价值与理论意义的开端。中国制霉菌素产生菌链丝菌S.aureusA94 S-7菌株,在制霉菌素发酵时,发酵滤液中伴有存在对超敏大肠杆菌(E.coliSS)、藤黄八叠球菌(S.lutea)、金黄色葡萄球菌(Staph.aureus)呈现活性的多种微量组成物,活性表现为模糊抑菌圈或透明抑菌圈。初步分离了滤液中共存的、导致对S.lutea呈透明抑菌圈和模糊抑菌圈的组分,紫外吸收光谱扫描结果显示:导致透明圈的粗品(YZ-8157A)max267.5及268.5 nm,导致模糊圈的粗品(YZ-8157B)max199.9 nm。