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PubMed1992

In vitro activity of Ro 23-9424, a dual-action antibacterial agent, against bacterial isolates from cancer patients compared with those of other agents.

The in vitro activity of Ro 23-9424 against bacterial isolates from patients with cancer was compared with those of fleroxacin, ciprofloxacin, cefoperazone, and ceftazidime. Ro 23-9424 inhibited the majority of the members of the family Enterobacteriaceae and all Aeromonas isolates at a concentration of less than or equal to 1.0 micrograms/ml. It was also active against Acinetobacter spp. and Haemophilus influenzae, including beta-lactamase-producing strains. The MIC for 90% of isolates (MIC90) of Pseudomonas aeruginosa was 16.0 micrograms/ml. All group A and B streptococci were inhibited by less than or equal to 0.25 micrograms/ml, and 90% of group G streptococci and Streptococcus pneumoniae were inhibited by 1.0 micrograms/ml. All methicillin-susceptible strains of Staphylococcus aureus and 60% of methicillin-resistant strains were susceptible to 2.0 micrograms of Ro 23-9424 per ml, whereas the MIC90 for Staphylococcus epidermidis and Staphylococcus hominis isolates was 4.0 micrograms/ml. Staphylococcus haemolyticus and Enterococcus spp. were less susceptible; MIC90s for them were 16.0 and 32.0 micrograms/ml. Ro 23-9424 has a broad antibacterial spectrum and potential utility for therapy of infections in cancer patients.

Anti-Infective Agents↗

PubMed1992

In-vitro activity of streptogramin RP 59500 against staphylococci, including bactericidal kinetic studies.

The in-vitro activity of RP 59500 and comparative agents was determined against 270 clinical isolates of the genus Staphylococcus. MICs were performed by micro-dilution dilution. MIC90 and MBC90 (mg/L) of RP 59500 were as follows: oxacillin-sensitive Staphylococcus aureus (0.5/0.5), oxacillin-resistant S. aureus (0.5/0.5), oxacillin-sensitive Staphylococcus epidermidis (0.5/0.5), oxacillin-resistant S. epidermidis (0.25/0.25), oxacillin-resistant Staphylococcus hominis (1.0/1.0), oxacillin-resistant Staphylococcus haemolyticus (1.0/1.0), oxacillin-sensitive Staphylococcus saprophyticus (1.0/1.0). Killing kinetic methods were used to assess the bactericidal activity of inhibitory (1 x, 2 x MIC) concentrations of RP 59500 in comparison with that of vancomycin (1 x, 2 x MIC) and oxacillin (1 x, 2 x MIC) against 20 strains of oxacillin-sensitive and -resistant S. aureus and S. epidermidis. RP 59500 was as active as vancomycin, displaying rapid bactericidal activity against the majority of strains tested and reducing initial inoculum counts by greater than 99.9% in 2-12 h. Regrowth was seen with some S. epidermidis strains after 12-24 h.

Drug Resistance, Microbial↗

PubMed1998

Molecular cloning of a 32-kilodalton lipoprotein component of a novel iron-regulated Staphylococcus epidermidis ABC transporter.

Our previous studies identified two iron-regulated cytoplasmic membrane proteins of 32 and 36 kDa expressed by both Staphylococcus epidermidis and Staphylococcus aureus. In this study we show by Triton X-114 phase partitioning and tritiated palmitic acid labelling that these proteins are lipoproteins which are anchored into the cytoplasmic membrane by their lipid-modified N termini. In common with those of some other gram-positive bacteria, these highly immunogenic lipoproteins were released from the bacterial cell into the culture supernatants, with release being promoted by growth of the bacteria under iron-restricted conditions. Immunoelectron microscopy with a monospecific rabbit antiserum to the 32-kDa S. epidermidis lipoprotein showed that the majority of the antigen was distributed throughout the staphylococcal cell wall. Only minor quantities were detected in the cytoplasmic membrane, and exposure of the lipoprotein on the bacterial surface was minimal. A monoclonal antibody raised to the 32-kDa lipoprotein of S. aureus was used in immunoblotting studies to investigate the conservation of this antigen among a variety of staphylococci. The monoclonal antibody reacted with polypeptides of 32 kDa in S. epidermidis and S. aureus and of 40 kDa in Staphylococcus hominis. No reactivity was detected with Staphylococcus lugdunensis, Staphylococcus cohni, or Staphylococcus haemolyticus. The gene encoding the 32-kDa lipoprotein from S. epidermidis has been isolated from a Lambda Zap II genomic DNA library and found to be a component of an iron-regulated operon encoding a novel ABC-type transporter. The operon contains three genes, designated sitA, -B, and -C, encoding an ATPase, a cytoplasmic membrane protein, and the 32-kDa lipoprotein, respectively. SitC shows significant homology both with a number of bacterial adhesins, including FimA of Streptococcus parasanguis and ScaA of Streptococcus gordonii, and with lipoproteins of a recently described family of ABC transporters with proven or putative metal ion transport functions. Although the solute specificity of this novel transporter has not yet been determined, we speculate that it may be involved in either siderophore- or transferrin-mediated iron uptake in S. epidermidis.

ATP-Binding Cassette Transporters↗

PubMedDate not supplied

[Coagulase-negative staphylococcal septicemia].

In the past decade, coagulase negative Staphylococcus (CNS) has become one of the most common pathogens in nosocomial septicemia, especially in neonatal intensive care units. From January 1, 1990 to June 30, 1992, we documented 41 cases of CNS septicemia in the Department of Pediatrics at Mackay Memorial Hospital. Thirty five cases (85%) were found in infants less than 3 months of age. Nineteen patients were premature babies. Of these, 14 had a body weight less than 1,500 gms. All of the patients had intravascular catheters and 40 patients (97.5%) were receiving total parenteral nutrition. The most common causative organism isolated in this study was Staphylococcus hominis. This differs from other reports where Staphylococcus epidermidis is the most common pathogen. Eighty five percent of the organisms were resistant to methicillin and 80% of these methicillin-resistant strains were also resistant to cephalosporins. All of the organisms were sensitive to vancomycin. Because of the possibility of cross-resistance between methicillin and cephalosporin, vancomycin was chosen to treat the methicillin resistant cases. Total parenteral nutrition was discontinued before antibiotic treatment. When CNS septicemia was suspected clinically, we drew two blood cultures from different sites before beginning antibiotic therapy. This was an effort to get a definitive diagnosis. In general, the prognosis of CNS septicemia was good if early diagnosis can be made.

Bacteremia↗

PubMed2005

Successful liver and kidney transplantation from cadaveric donors with left-sided bacterial endocarditis.

Bacterial infections are frequent in cadaveric organ donors and can be transmitted to the transplantation recipient, which could have devastating consequences for the recipients if adequate preventive measures are not adopted. From the 355 consecutive brain dead cadaveric organ donors procured at our center in the last four years, 2000-2003, four of them (1.1%) had bacterial endocarditis as cause of death. The bacteria responsible for the endocarditis were Staphylococcus epidermidis, coagulase-negative Staphylococcus, Staphylococcus hominis and Streptococcus viridans, respectively. We performed five kidney and two liver transplantations on seven recipients. All donors and recipients received antibiotic treatment against the germ causing the respective endocarditis. Infection by the bacteria responsible for the endocarditis in the respective donors was not transmitted to any of the recipients. Six of the seven recipients were alive with normal-functioning grafts after between 13 and 24 months' follow-up. Transplantectomy was performed on one kidney recipient due to thrombosis of the renal vein of the graft not related to the endocarditis. Liver and kidney transplantation from donors dying from bacterial endocarditis can be performed without causing the transmission of infection to the recipient or the dysfunction of the graft.

Adult↗

PubMed1992

Effect of various microbial preparations on P-388 mouse lymphocytic leukemia.

Four bacteria-derived immunopotentiators were tested for their protective effect on a P-388 mouse lymphocytic leukemia model. The microbial test products were prepared from the following bacterial strains: ATCC 35983 Staphylococcus epidermidis isolated from a patient with IV catheter; ATCC 31874, a patented strain listed as Staphylococcus epidermidis isolated from the urine of a cancer patient; ATCC 25615 Staphylococcus hominis obtained from a child with lymphocytic leukemia, and ATCC 25614 Staphylococcus warneri, an isolate from a patient with adenocarcinoma of the breast. A limited degree of protection and prolongation in survival time was observed in the animal group treated with the bacterial strain ATCC 31874.

Adjuvants, Immunologic↗

PubMed1981

Effects of test conditions on the susceptibility of staphylococci in vitro to cephradine, cephaloridine, cephalexin, and cefuroxime.

Methicillin-resistant staphylococci were tested for susceptibility to cephradine, cephaloridine, cephalexin, and cefuroxime and 30 degree C and 37 degree C on ordinary media and on media of enhanced osmotic strength. The coagulase-negative strains were divided into Staphylococcus epidermis and Staphylococcus hominis. Generally the number of susceptible strains decreased with low incubation temperature and osmotic support. When Staphylococcus aureus was tested against cephalexin and cefuroxime, most were susceptible at 37 degree C whereas all were resistant at 30 degree C. A similar trend was found in the case of cephradine, where it was accentuated by osmotic support. While almost all strains of Staph. epidermidis were sensitive to all four drugs under all test conditions, the susceptibility of Staph. hominis was generally decreased by either lower incubation temperature or osmotic support or both.

Cefuroxime↗

PubMed1996

Susceptibility of corneal and conjunctival pathogens to ciprofloxacin.

Ciprofloxacin 0.3% ophthalmic solution has been shown to be effective in the treatment of bacterial keratitis and conjunctivitis, and many physicians use ciprofloxacin as sole therapy in these conditions. In this retrospective study, we found seven of 84 isolates from corneal and conjunctival cultures that were resistant to ciprofloxacin. All of the resistant organisms were gram positive. Six of the isolates (Staphylococcus aureus, Staphylococcus hominis, and four isolates of the Streptococcus viridans group) were from corneal cultures, and one (Staphylococcus aureus) was from a conjunctival culture. Yearly records of systemic isolates from 1988 to 1993 (n = 35,308) demonstrated a statistically significant decrease in susceptibility for several organisms that are common pathogens in the conjunctiva and cornea: Pseudomonas aeruginosa (95-90%, p = 0.001); Staphylococcus aureus (96-87%, p < 0.0001); Staphylococcus spp., coagulase negative (97-81%, p < 0.0001); Enterococcus spp. (92-79%, p < 0.0001); Acinetobacter anitratus (97-77%, p = 0.0006); and Enterobacter cloacae (100-96%, p = 0.03). Although the susceptibility of corneal and conjunctival isolates in this series remained relatively high (91.7%), a much larger series of systemic isolates that are common ocular pathogens revealed a statistically significant increase in resistance to ciprofloxacin over the preceding 5 years.

Anti-Infective Agents↗

PubMed1991

Encapsulation of coagulase-negative staphylococci of bovine origin.

Capsule expression was assessed in six coagulase-negative staphylococcal strains in serum-soft agar and by india ink and electron microscopy. Classification of strains as encapsulated by serum-soft agar and india ink methods differed. Staphylococcus chromogenes, Staph. hyicus, and Staph. simulans grew as diffuse colonies in serum-soft agar and unstained halos were detected in india ink preparations. Staphylococcus hominis and Staph. simulans grew as diffuse colonies in serum-soft agar but no unstained halo was seen in india ink preparations. Staphylococcus hyicus was the only strain that gave negative results with serum-soft agar and india ink assays. Conventional electron microscopy revealed the presence of capsular polysaccharides on the cell surface of Staph. chromogenes, Staph. hominis and Staph. hyicus. Conventional electron microscopic technique used to examine the surface of cells was detrimental to capsule structure. During dehydration the capsule collapsed and appeared as electron dense aggregates at the surface of cells. To confirm results of conventional electron microscopy and to visualize clearly the cell surface, encapsulated Staph. hyicus and unencapsulated Staph. simulans were observed after freeze-fracture and etching by scanning electron microscopy. The fibrous nature of capsular polysaccharides surrounding cells of Staph. hyicus were distinct and confirmed observation by conventional electron microscopy. A rapid transmission electron microscopic technique is described also for observation of capsule. Results of the rapid TEM method agreed with conventional TEM and SEM. The finding that coagulase-negative staphylococci isolated from bovine milk are capable of capsule production may be important when investigating pathogenicity of these micro-organisms.

Animals↗

PubMed2002

The antibacterial activity of topical retinoids: the case of retinaldehyde.

BACKGROUND: Retinoids such as retinoic acid (RA), retinol (ROL) and retinaldehyde (RAL) are currently used in many formulations and indications ranging form acne to skin aging. Most if not all their pharmacological activities occur through binding to nuclear receptors with subsequent modulation of the activities of several genes. Little attention has been given to the many other potential actions on the surface of the skin. AIM: To analyse the potential anti-infective activities of topical ROL, RAL and RA. METHODS: Microbial minimal inhibitory concentrations (MIC) of ROL, RAL and RA were determined by a microdilution method on reference strains including Staphylococcus aureus, Staphylococcus epidermidis, Micrococcus flavus, Propionibacterium acnes, Micrococcus luteus, Enterococcus faecium, Staphylococcus hominis, Escherichia coli, Pseudomonas aeruginosa, Candida albicans and 133 clinical strains including methicillin-resistant S. aureus, methicillin-sensitive S. aureus, coagulase-negative Staphylococcus, Streptococcus group B, Enterococcus faecalis, vancomycin-resistant E. faecalis, vancomycin-resistant E. faecium and Pseudomonas/Klebsiella. In two clinical trials in healthy human volunteers, skin bacterial densities were evaluated in samples obtained with the cylinder scrub method: (1). 2 and 5 h after a single application of 0.05% RAL or vehicle on the forearm and (2). in a single-blind randomized study where 0.05% RAL or vehicle were applied daily for 2 weeks on the forehead of 22 volunteers. Paired results from treated (or vehicle) and untreated areas were analysed. RESULTS: Of the three retinoids tested, only RAL showed a significant in vitro antibacterial activity; this activity was found against reference strains of gram-positive bacteria like S. aeureus, Micrococcus spp. or P. acnes. No activity was found against gram-negative bacteria. These results on reference strains were confirmed on 133 clinical isolates. MIC(50) and MIC(90) values for RAL were 8 and 16 mg/l, respectively, for methicillin-sensitive S. aureus and 4 and 8 mg/l for methicillin-resistant S. aureus. The two in vivo studies showed that areas treated with RAL had a significant decrease in the bacterial counts. In the forehead study, the median decrease was 10(2) log/cm(2) for P. acnes and 10(1.8) log/cm(2) for staphylococci. No resistant bacteria were found after 2 weeks of topical use. Preliminary results suggest that the antibacterial effect of RAL is due, in part, to the aldehyde group in the lateral chain, since non-retinoid pseudo-analogues of the chain, like citral and hexenal, showed a similar antibacterial activity. CONCLUSION: We have shown that RAL differs from parent natural retinoids such as ROL and RA in demonstrating significant antibacterial activities upon topical use. This activity is likely due to the aldehyde group in the isoprenoic lateral chain, which illustrates the potential bifunctional properties of some retinoids.

Bacteria↗

PubMed1990

Pathogenicity of Staphylococcus lugdunensis, Staphylococcus schleiferi, and three other coagulase-negative staphylococci in a mouse model and possible virulence factors.

Staphylococcus lugdunesis and Staphylococcus schleiferi, two newly described species, have been isolated from numerous types of human infections. We compared the pathogenicity of 30 strains of S. lugdunensis, S. schleiferi, Staphylococcus epidermidis, Staphylococcus warneri, and Staphylococcus hominis, using a mouse model in which a foreign body preadhered with the test strain was implanted subcutaneously, followed by injection of the test strain. All five species of staphylococci produced abscesses. Staphylococcus epidermidis, S. schleiferi, and S. lugdunensis yielded species means of 76-91% abscess formation; 80-100% of the infected foreign bodies and tissues were culture positive. These three species were more virulent than S. warneri or S. hominis, which produced abscesses in 54 and 65% of mice, respectively; only 10-48% of the infected samples were culture positive. Transmission electron microscopy of pure cultures of selected strains showed that all species possessed glycocalyx. All species produced a variety of possible virulence factors, such as alpha and delta hemolysins, as well as the aggressins lipase and esterase. The production of exoenzymes did not always correlate with virulence as demonstrated by abscess formation in mice.

Abscess↗

PubMed1998

Changes in bacterial flora associated with skin damage on hands of health care personnel.

In a prospective observational study of 40 nurses (20 with diagnosed hand irritation and 20 without), nurses with damaged hands did not have higher microbial counts (P = .63), but did have a greater number of colonizing species (means: 3.35 and 2.63, P = .03). Although numbers were small, nurses with damaged hands were significantly more likely to be colonized with Staphylococcus hominis (P = .03). Fifty-nine percent of S hominis isolates from nurses with damaged hands were resistant to methicillin compared with 27% of isolates from those with healthy skin (P = .14). Twenty percent of nurses with damaged hands were colonized with Staphylococcus aureus compared with none of the nurses with normal hands (P = .11). Nurses with damaged hands were also twice as likely to have gram-negative bacteria (P = .20), entercocci (P = .13), and Candida (P = .30) present on the hands. Antimicrobial resistance of the coagulase-negative staphylococcal flora (with the exception of S hominis) did not differ between the 2 groups, nor did a trend toward increasing resistance exist when compared with other studies during the past decade. Skin moisturizers and protectant products were used almost universally by nurses at work, primarily products brought from home. Efforts to improve hand condition are warranted because skin damage can change microbial flora. Such efforts should include assessment or monitoring of hand care practices, formal institutional policy adoption and control of use of skin protectant products or lotions, and prudent use of latex gloves or more widespread use of powder-free and nonlatex products.

Adult↗

PubMed2001

Molecular techniques open up new vistas for typing of coagulase-negative staphylococci.

Several methods were used to type 64 clinical isolates of coagulase-negative staphylococci (CNS) derived from hospitals in Morocco. The clinical isolates originated principally from blood cultures and wound sources. These isolates provided the opportunity to substantially compare the proficiency of developing molecular techniques with conventional phenotypic tests for use in the identification of clinical staphylococci. The following molecular methods were examined: Utility ribotyping analysis (Ribotyping); PCR analysis performed with 16S-23S ribosomal-DNA intergenic spacer (ITS-PCR); PCR-based random amplified polymorphic DNA (RAPD). The results obtained by the molecular techniques were contrasted to those of conventional phenotypic tests. Conventional phenotypic tests allowed the outright recognition of the majority of isolates (50/64). These 50 isolates were subdivided into 33 novobiocin-susceptible and 17 novobiocin-resistant strains of CNS. However, 2 other novobiocin-susceptible and 12 other novobiocin-resistant isolates remained unclassified by these tests. There was a good agreement between the conventional phenotypic tests and RAPD for the 33 novobiocin-susceptible isolates. But, the RAPD technique permitted the assignment of the two unidentified novobiocin-susceptible isolates to the Staphylococcus hominis species. A complete correlation was obtained between the three molecular tools for recognition of the 12 novobiocin-resistant isolates that were not identified by phenotypic typing; these were in fact identified as 5 Staphylococcus cohnii and 4 Staphylococcus equorum. Three isolates remained unidentified by all three systems of molecular techniques.

Bacterial Proteins↗

PubMed1983

Evaluation of the automicrobic system gram-positive identification card for species identification of coagulase-negative staphylococci.

The AutoMicrobic system Gram-Positive Identification Card (Vitek Systems, Inc., Hazelwood, Mo.) was evaluated for identification of a group of 150 isolates of coagulase-negative staphylococci. Identifications obtained with the Gram-Positive Identification Card were compared with reference identifications derived from 15 conventional biochemical tests. The AutoMicrobic system correctly identified only 67.3% (101 of 150) of the test isolates. The greatest accuracy was achieved with Staphylococcus epidermidis isolates (95.7%), whereas Staphylococcus hominis isolates were least often correctly identified (26.7%).

Bacteriological Techniques↗

PubMed1999

Chemical analysis and antimicrobial activity of the resin Ladano, of its essential oil and of the isolated compounds.

Fractionation of the resin Ladano from Cistus creticus subsp. creticus and susceptibility testing using the chromatographic fractions showed that its antistaphylococcal activity was mainly due to the diterpene sclareol. The antimicrobial activity of its essential oil, of the chromatographic fractions, and of the isolated compounds was also evaluated against Staphylococcus aureus, Staphylococcus epidermidis, and Staphylococcus hominis.

Anti-Bacterial Agents↗

PubMed1995

Evaluation of new agglutination test for identification of oxacillin-susceptible and oxacillin-resistant Staphylococcus aureus.

A new agglutination test (Monostaph +; Bionor, Skien, Norway) has been developed. This new agglutination test has been compared with two other agglutination tests for the identification of 128 isolates of Staphylococcus aureus and 82 coagulase-negative staphylococci. The sensitivities of both Monostaph + and Pastorex Staph-Plus were excellent (98.7 and 97.4%, respectively) in detection of oxacillin-resistant Staphylococcus aureus. The specificity was 96.4% (two Staphylococcus epidermidis isolates and one Staphylococcus hominis isolate were false positive).

Agglutination Tests↗

PubMed1998

Increased oxacillin activity associated with glycopeptides in coagulase-negative staphylococci.

Vancomycin resistance in methicillin-resistant staphylococci presents a potential therapeutic problem. In order to understand the impact of low-level vancomycin resistance in coagulase-negative staphylococci, stepwise selection of vancomycin resistance was accomplished by growing Staphylococcus haemolyticus in culture media with increasing concentrations of vancomycin. A >40-fold increase in susceptibility to beta-lactam antibiotics was observed. No obvious alterations in the growth curve, the presence of the mecA gene, total DNA restriction fragment length polymorphism (RFLP), beta-lactamase production, or the crude protein fraction were detected in the Staphylococcus haemolyticus-derived clones when compared to the original isolate. The proportion of the oxacillin-heteroresistant population also remained similar. A comparable phenomenon occurred with the selection of Staphylococcus epidermidis exhibiting low-level resistance to vancomycin. Additionally, it was observed that clinical isolates of coagulase-negative staphylococci grown in the presence of sub-minimum inhibitory concentrations of either vancomycin or teicoplanin lost their high-level resistance to oxacillin. Checkerboard tests showed that the combination of vancomycin and oxacillin was synergistic for two isolates of Staphylococcus haemolyticus, two of four isolates of Staphylococcus epidermidis, and one isolate of Staphylococcus hominis.

Anti-Bacterial Agents↗

PubMed1983

Identification of Staphylococcus species of bovine origin with the API Staph-Ident system.

The API Staph-Ident system was evaluated as a means for identifying the species of bovine strains of staphylococci routinely isolated from quarter-milk samples. The species identity of 314 of 581 (54%) isolates of staphylococci was correctly determined by this method. The API Staph-Ident system was more accurate in correctly identifying Staphylococcus aureus (93.9%) than in correctly identifying non-S. aureus species (41.8%). False identifications of Staphylococcus epidermidis and Staphylococcus hominis were the main reasons for the incorrect identifications of the non-S. aureus species.

Animals↗