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PubMed1999

[Typing of methicillin resistant strains of S. haemolyticus isolated from patients and from the hospital ward environment].

Biotyping, antibiograms and fingerprinting were used to determine the relation of 16 methicillin-resistant S. haemolyticus isolated from drains in patients who underwent intraabdominal surgery to 9 methicillin-resistant strains of S. haemolyticus isolated at the same time from hospital environment. The comparison of biochemical properties of the examined strains showed a large variety of biochemical profiles as well as antibiotic patterns of susceptibility. The differences in sensitivity to the antibiotics used were not distinct. Biotyping and antibiograms did not permit determination of the relation of the investigated strains. Only the results of fingerprinting allowed for the division of the 25 examined strains into three genotypes demonstrating three main patterns of PCR products. 16 strains of 25 showed the same pattern of PCR products. This results suggests the presence of a source of infection on the clinical ward. A nurse may have been the source of infection because the same genotype of S. haemolyticus was isolated from her nasal anterior as from the majority of patients.

Cross Infection↗

PubMed1992

An analysis of the microbial flora of premature neonates.

An analysis of the microbial flora of 10 premature neonates hospitalized in a neonatal intensive care unit (NICU) was made. The babies had received neither antibiotics nor antiseptics and nine out of 10 were born by caesarean section. Samples were collected on the fourth or fifth day of life from 18 skin or mucosal sites. Detailed bacterial counts were obtained by plating out suitable dilutions of the samples on to selective media. Representative samples of each colony type were then subcultured and identified, using standard laboratory methods. Two hundred and fifty-six isolates of staphylococci were obtained and their susceptibility to 23 antibiotics tested. Only 11% of the samples were sterile. Coagulase-negative staphylococci (CNS) were the commonest species isolated and were predominant in every site studied. They were found in 79% of the samples and represented almost 81% of the neonates' flora. Eight species and biotypes of CNS were identified. In decreasing order of frequency, they comprised S. epidermidis (biotypes 1 and 2), S. hominis (biotype 1), S. warneri, S. haemolyticus, S. capitis, S. cohnii and S. hominis (biotype 2). CNS distribution appeared to be highly heterogeneous with no significant specificity of any species for a particular body site. The main quantitative and qualitative variations seemed to relate to the method of delivery, and the intensity and nature of exposure of the neonate to its local environment. A high level of antibiotic resistance was found among the CNS isolates (especially S. epidermidis and S. haemolyticus): penicillin G (96%), oxacillin (31%), erythromycin (52%) and gentamicin (28%). Moreover, multiresistant strains were numerous, supporting the nosocomial origin of CNS.

Bacterial Typing Techniques↗

PubMed1998

SirR, a novel iron-dependent repressor in Staphylococcus epidermidis.

In Staphylococcus epidermidis and Staphylococcus aureus, a number of cell wall- and cytoplasmic membrane-associated lipoproteins are induced in response to iron starvation. To gain insights into the molecular basis of iron-dependent gene regulation in the staphylococci, we sequenced the DNA upstream of the 3-kb S. epidermidis sitABC operon, which Northern blot analysis indicates is transcriptionally regulated by the growth medium iron content. We identified two DNA sequences which are homologous to elements of the Corynebacterium diphtheriae DtxR regulon, which controls, in response to iron stress, for example, production of diphtheria toxin, siderophore, and a heme oxygenase. Upstream of the sitABC operon and divergently transcribed lies a 645-bp open reading frame (ORF), which codes for a polypeptide of approximately 25 kDa with homology to the DtxR family of metal-dependent repressor proteins. This ORF has been designated SirR (staphylococcal iron regulator repressor). Within the sitABC promoter/operator region, we also located a region of dyad symmetry overlapping the transcriptional start of sitABC which shows high homology to the DtxR operator consensus sequence, suggesting that this region, termed the Sir box, is the SirR-binding site. The SirR protein was overexpressed, purified, and used in DNA mobility shift assays; SirR retarded the migration of a synthetic oligonucleotide based on the Sir box in a metal (Fe2+ or Mn2+)-dependent manner, providing confirmatory evidence that this motif is the SirR-binding site. Furthermore, Southern blot analysis of staphylococcal chromosomal DNA with the synthetic Sir box as a probe confirmed that there are at least five Sir boxes in the S. epidermidis genome and at least three in the genome of S. aureus, suggesting that SirR controls the expression of multiple target genes. Using a monospecific polyclonal antibody raised against SirR to probe Western blots of whole-cell lysates of S. aureus, S. carnosus, S. epidermidis, S. hominis, S. cohnii, S. lugdunensis, and S. haemolyticus, we identified an approximately 25-kDa cross-reactive protein in each of the staphylococcal species examined. Taken together, these data suggest that SirR functions as a divalent metal cation-dependent transcriptional repressor which is widespread among the staphylococci.

Amino Acid Sequence↗

PubMedDate not supplied

The prevalence of staphylococcal resistance to penicillinase-resistant penicillins. A retrospective and prospective national surveillance trial of isolates from 40 medical centers.

In a retrospective survey of resistance to penicillinase-resistant penicillins (PRPs) in 152,076 clinical staphylococcal strains isolated in 40 United States Hospitals in 1985 and 1986, rates of resistance to oxacillin were found to be 11 and 13%, respectively, among Staphylococcus aureus isolates. The rates were approximately four times higher among coagulase-negative staphylococcal strains. In a prospective study of 1,408 wound or bacteremia isolates from the participant hospitals, oxacillin and methicillin agar screening, disk diffusion, and broth microdilution testing were conducted at a single reference laboratory. These tests yielded PRP resistance rates of 15% among S. aureus, 75% among S. epidermidis, and 48% among other coagulase-negative strains. No major changes in the distribution of resistance rates among hospitals or by hospital type were observed. Dilution susceptibility testing of several antimicrobial agents against PRP-resistant isolates and species-matched susceptible isolates from the same hospital showed that teicoplanin and vancomycin were the most active drugs (100% of S. aureus isolates were susceptible). Teicoplanin and vancomycin disk diffusion testing of all PRP-resistant staphylococcal strains also showed that these isolates were susceptible to the glycopeptides. However, agar dilution screening and broth microdilution tests revealed that several coagulase-negative strains, predominantly S. haemolyticus, had teicoplanin MICs greater than or equal to 8 micrograms/ml. S. haemolyticus isolates represented a very small number of the total stains tested. Teicoplanin and vancomycin were also the most active drugs when tested against older (1962-82) clinical PRP-resistant S. aureus strains from the reference laboratory collection. The methods found to be superior in detecting PRP-resistant strains were the oxacillin 6 micrograms/ml agar screening test in 4% NaCl-supplemented Mueller-Hinton agar and the 1 microgram oxacillin disk test. By reference laboratory standards, participant laboratories were incorrect in only 2.3% of species identifications and 4.5% of oxacillin-susceptibility determinations, indicating acceptable contemporary agreement and accuracy.

Anti-Bacterial Agents↗

PubMed1985

Application of current methods for isolation and identification of staphylococci in raw bovine milk.

Samples of raw milk were examined for counts of somatic cells, total viable bacteria, staphylococci (Schleifer & Kramer's medium) and Staphylococcus aureus (Baird-Parker medium, Baird-Parker medium with pig plasma and Baird-Parker medium with additional antibiotics). For the isolation of staphylococci from raw milk, Schleifer & Kramer's medium was found to be very selective and in general performed satisfactorily. From the results obtained with the three remaining media the continued use of Baird-Parker medium for isolation of Staph. aureus from raw milk is recommended with the proviso that colonies selected for identification should include those that clear and do not clear the egg yolk and are not limited to colonies with diameters greater than 1 mm. Staphylococci isolated from raw milk were identified by key tests using a multipoint inoculation procedure. A selected number were also examined by the API STAPH system in conjunction with the API LAB computer programme for identification of staphylococci. Of the staphylococci examined, 90.0% were identified using the multipoint procedure. For strains identified as Staph. aureus, Staph. hyicus subsp. hyicus, Staph. epidermidis, Staph. simulans, Staph. xylosus or members of the Staph. hominis/Staph. warneri/Staph haemolyticus group, the API system provided confirmatory evidence. With strains identified by the multipoint procedure as Staph. hyicus subsp. chromogenes, Staph. sciuri subsp. sciuri and Staph. sciuri subsp. lentus the API system did not always provide concurring results. Several strains which could not be identified by the multipoint procedure could be identified by the API system. Staph. aureus, Staph. hyicus subsp. hyicus and Staph. hyicus subsp. chromogenes strains isolated from milk were examined for production of enterotoxin A-E. Only 3.9% of Staph. aureus strains examined produced detectable enterotoxin (type C). None of the Staph. hyicus subsp. hyicus or Staph. hyicus subsp. chromogenes strains produced any of the known enterotoxins.

Animals↗

PubMedDate not supplied

[Markers of the persistence of the staphylococcal air microflora in a hospital].

The presence of persistence markers of some staphylococcal species isolated from the air at an obstetric hospital was established. The presence of such markers was most pronounced in S. aureus, which was indicative of its absolute value for characterizing the sanitary state of the environment. Staphylococci of coagulase-negative species were characterized by the presence of antilysozyme activity, as well as by their ability to inactivate the antibacterial component of the preparation of interferon, most pronounced in microorganisms of the species S. epidermidis and S. haemolyticus. Disinfecting measures, carried out with the use of ozone, made it possible to normalize the quantitative and qualitative characteristics of bacterial aerosol, which was mainly manifested by the air elimination of staphylococci having a set of persistence markers, as well as the capacity for producing hemolysin.

Air Microbiology↗

PubMed1992

Phage typing of coagulase-negative staphylococci.

Seventy-nine staphylococcal strains isolated from blood cultures (57 coagulase-negative staphylococci (CNS) and 22 S. aureus) and 308 CNS isolated from the skin of healthy donors were phage typed. S. epidermidis and S. capitis were readily typed with 91 strains out of 124 and 24 strains out of 43 strains being successful. Species such as S. haemolyticus, S. hominis and S. simulans could be moderately phage typed. Others gave only a few strains capable of being typed, such as S. saprophyticus and S. sciuri. Under our experimental conditions the S. warneri, S. xylosus and S. cohnii could not be typed with our set of phages.

Bacteriophage Typing↗

PubMed1993

Molecular characterization of the coagulase-negative staphylococcal surface flora of premature neonates.

A single point study was conducted to determine which surface sites best represent the density and composition of the coagulase-negative staphylococcal (CNS) colonizing flora in premature neonates. Five different surface sites of six randomly selected neonates hospitalized in a neonatal intensive care unit (NICU) for a month were examined. The individual strains and their clonal organization within CNS species were identified using restriction endonuclease fingerprinting of whole chromosomal DNA and ribosomal RNA genes. Cultures of the scalp, umbilicus, foot, nose and rectum were collected and quantitatively processed. Ten colonies were typed per surface culture. The most dense CNS colonization was noted on the umbilicus (mean 1.2 x 10(4) c.f.u. cm-2), foot (mean 1.6 x 10(3) c.f.u. cm-2) and nose (mean 1.7 x 10(3) c.f.u. cm-2) of NICU neonates. Scalp and rectum were scarcely colonized. Of all the CNS surface isolates, S. epidermidis accounted for 77.7% (219/282) and S. haemolyticus, S. warneri and S. capitis accounted for 20.6% (58/282), 1.4% (4/282) and 0.4% (1/282), respectively. Colonization of each surface site comprised a maximum of five different strains representing four CNS species. Overall, five clones of S. epidermidis, two of S. haemolyticus, one of S. warneri and one of S. capitis were noted among the 282 isolates. The most predominant were two clones of S. epidermidis and one of S. haemolyticus; they accounted for 94% (265/282). Cultures from the foot and scalp represented the most heterogeneous CNS colonization of the five sites examined.(ABSTRACT TRUNCATED AT 250 WORDS)

Bacteremia↗

PubMed1990

In vitro activity of ramoplanin on staphylococci.

Approximately 1000 strains of staphylococci isolated from the skin of patients before and after coronary artery by-pass surgery were speciated using the API-Staph system, and tested for susceptibility to ramoplanin and teicoplanin. In addition flucloxacillin MICs were available for 750 strains. MICs were performed by incorporating dilutions of antibiotics in 'Isosensitest' Agar (Oxoid) and applying approx 10(4) cells by a multi-point inoculator. The strains tested (numbers in brackets) included: Staph. epidermidis (352), Staph. haemolyticus (133), Staph. simulans (104), Staph aureus (69), Staph. hominis (54), Staph. warneri (39), Staph. capitis (23), Staph. saprophyticus (12), Staph. cohnii (6) and Staph. sciuri (2). The overall MICs were: ramoplanin MIC 50%: 0.5 mg/l, MIC 90%: 1 mg/l; teicoplanin MIC 50%: 2 mg/l, MIC 90%: 8 mg/l. Ramoplanin MICs of greater than 2 mg/l were only found for 17 strains from eleven patients which included: Staph. simulans (6), Staph. haemolyticus (4) and Staph. epidermidis (2). The maximum MIC however was only 8 mgl, so no strains were ramoplanin-resistant. There was no relationship between ramoplanin and flucloxacillin MICs; but despite their differing modes of action, the strains with higher ramoplanin MICs also had higher teicoplanin MICs.

Anti-Bacterial Agents↗

PubMed1989

A study of coagulase-negative staphylococci isolated from clinically significant infections at an Australian teaching hospital.

Some 151 isolates of coagulase-negative staphylococci isolated from patients at an Australian teaching hospital were characterized by biochemical analysis, antibiotic sensitivity patterns and slime production. S. epidermidis was the predominant species (64%) isolated from clinically significant infections, and all S. epidermidis isolates from true bacteremias produced slime. Forty-nine per cent were resistant to methicillin and 61% to gentamicin. S. haemolyticus isolates from clinically significant infections also showed antibiotic resistance and 80% were resistant to more than five antibiotics. The importance of coagulase-negative staphylococci as pathogens in this large teaching hospital was confirmed.

Anti-Bacterial Agents↗

PubMed1991

[Coagulase-negative staphylococci--problem bacteria in the hospital. Identification and resistance status].

131 coagulase-negative staphylococci (CNS) of clinical significance were investigated during the period 1989-1990 in Northern Norway. The staphylococci were isolated from blood cultures (68/131, 51.9 per cent), vascular catheters (6/131), patients with osteomyelitis (13/131), postoperative and other wounds (15/131) and urinary tract infections (29/131). The staphylococci were mostly from hospitalized patients (114/131). Vitek's GPI and Rosco's Staph-zym both gave a primarily correct identification in 95 per cent of the cases. S epidermidis was the predominant species (96/131; 73.3 per cent). Methicillin resistance (MR) was found in 30.5 per cent (40/131) of all CNS and in 35.4 per cent (34/96) of S epidermidis. Methicillin resistant S epidermidis isolates were usually resistant to gentamicin (25/34, 73.5 per cent). S haemolyticus was the most resistant species with MR in 5/7 strains. MR imply resistance to all beta-lactam antibiotics, including imipenem. Among S epidermidis, an increased MR from 10 per cent in 1987 to 35.4 per cent in 1989-1990 was observed. All strains were sensitive to vancomycin and rifampicin.

Coagulase↗

PubMed1983

Species identification and antibiotic susceptibilities of coagulase-negative staphylococci isolated from clinical specimens.

Identification of potentially significant coagulase-negative staphylococci isolated from clinical specimens was performed along with antibiotic susceptibility determinations, S. epidermidis accounted for 75% of these isolates, with S. haemolyticus and S. hominis being the second and third most frequently encountered species, respectively. Although there were many instances of single blood culture isolations of questionable significance, all three species were also found in multiple blood cultures from individual patients, indicating the ability to cause significant bacteremia. The most common source for most species was blood, except for S. saprophyticus and S. simulans, which were found more frequently in urine. Of urinary tract isolates, however, S. epidermidis was more common than S. saprophyticus. Antibiotic susceptibility profiles demonstrated that S. haemolyticus and S. epidermidis were frequently multiply antibiotic resistant. S. haemolyticus had a higher percentage of isolates that were oxacillin, cephalothin, aminoglycoside, erythromycin, and clindamycin resistant than did S. epidermidis. We found that species identification could be of benefit for both epidemiological as well as patient care purposes, and that this additional information is readily available, using convenient and rapid new methods.

Anti-Bacterial Agents↗

PubMed2003

[Optimizing microbiological controls of corneal organ culture media].

BACKGROUND/AIMS: To compare the efficiency of an automated method using blood bottles with conventional microbiological tests for controlling sterility in cornea organ culture media. METHODS: Two complementary studies were conducted. Experimental study: standard organ culture media were contaminated with four different inocula of 14 bacteria and 3 fungi. The bactericidal activity of organ culture media were evaluated after 48 hours of incubation at 31C. Observational study: 357 samples of organ culture media were collected over 1 year in our cornea bank. For both studies, media were inoculated in three blood bottles (aerobic, anaerobic, fungal) placed in an automat with automated detection every 10 minutes, and in three conventional microbiological media as a control. Changes in organ culture medium color and growth on conventional broth were checked daily by visual inspection. All samples were observed experimentally for 14 days. The sensitivity and rapidity of contamination detection were compared across the three methods: blood bottles, conventional method, and visual inspection of medium color. RESULTS: Experimental study: organ culture medium eradicated five bacteria: S. pneumoniae, B. catarrhalis, E. coli, P. acnes and H. influenzae. For the others, (Methicillin-resistant S. aureus, Methicillin-sensitive S. aureus, S. epidermidis, S. haemolyticus, P. aeruginosa, A. baumannii, B. subtilis, K. pneumoniae, E. faecalis, C. albicans, C. kruzei, A. fumigatus) the blood bottle method, the conventional microbiological method, and the visual inspection detected microbiological growth respectively in 100%, 76.5%, and 70% of cases. Mean detection time using blood bottles was 15.1 hours (standard deviation, 13.8; range, 2-52). In cases of detection by the blood-bottle method and the conventional method, the former was always faster: 95.5% versus 65.2% detection within 24 hours (p=0.022). Observational study: the global contamination rate was 8% (29/357 analysis). The gain in sensitivity with blood bottles was 25% compared with the conventional method. Five bacteria (three coag. neg Staphylococcus, one E. faecalis, one P. paucimobilis) were detected only by the blood bottles. In addition, these were always detected more quickly with, respectively, 66.6% versus 26.6% detection with 24 hours (p=0.028). CONCLUSIONS: Blood bottles detect contaminations of cornea organ culture media more efficiently and faster than conventional microbiological methods. They make it possible to reduce the quarantine period with an equally high security level. Consequently, they should be recommended in cornea preservation guidelines.

Bacteria↗

PubMed1995

Antimicrobial resistance of coagulase-negative staphylococci from a Kuwait hospital.

This study investigated the incidence of antimicrobial resistance in clinically significant coagulase-negative staphylococci at the Mubarak Al Kabeer Hospital, Kuwait. A total of 104 isolates of coagulase-negative staphylococci consisting of S. epidermidis (67), S. haemolyticus (16), S. saprophyticus (6), S. simulans (2), S. hominis (4), S. albus (2), S. sciuri (3), S. warneri (2), S. capitis (1), and S. xylosus (1) were isolated from clinical specimens over a 6-7 month period and tested for resistance to 22 antibacterial agents and the ability to produce slime. They were all susceptible to vancomycin and mupirocin but intermediate resistance to teicoplanin was detected in seven isolates: 83 and 47.7% were resistant to penicillin G and methicillin, respectively, 57% were resistant to gentamicin, 49.5% to erythromycin, 50.4% to tetracycline, and 52.3% to trimethoprim. Resistance to heavy metals and the nucleic-acid binding compound was also detected. More than half of S. epidermidis, S. saprophyticus, S. simulans, S. hominis, and all of S. haemolyticus were multiply resistant to three or more groups of antibiotics and there was a significant association between slime production and resistance to multiple antimicrobial agents in S. epidermidis. The results revealed a high level of resistance to commonly used agents.

Anti-Bacterial Agents↗

PubMed2001

Airborne coagulase negative staphylococci produced by a sewage treatment plant.

Since some coagulase-negative staphylococci species are involved in clinical and environmental situations, the authors carried out a study on the spread of these bacteria in the air of a sewage treatment plant. For these purposes a total of 196 samples were taken from 16 sampling stations, 11 during the day and 5 at night (only at 4 points), using the settle plate technique. Altogether 13 species of coagulase negative staphylococci were isolated: S. haemolyticus, S. xylosus and S. cohnii were particularly common. Station no. 2 (an area almost always kept closed containing the fine screens) was found to be the most contaminated. The presence of coagulase negative staphylococci was favoured by high temperatures and low humidity. No differences were found due to variations in wind speed and direction or between day and night.

Air Pollutants↗

PubMed1968

Bacteriology and clinical significance of hemolytic Haemophilus in the throat.

Hemolytic Haemophilus are rarely isolated in the clinical laboratory, as they do not grow on sheep or human blood-agar alone. On rabbit blood-agar they grow well and are hemolytic, but they grow less well and are not hemolytic on sheep blood-agar with added X and V factors. A survey was made to determine their incidence in pharyngitis. From 28 of 100 sore throats and from 57 of 100 normal throats, only normal bacterial flora were isolated. beta-Streptococci were present in significant numbers in 9 sore and 11 normal throats; staphylococci in 8 sore and 4 normal throats; pneumococci in 20 sore and 11 normal throats; H. influenzae or H. parainfluenzae in 13 sore and no normal throats; hemolytic Haemophilus in 30 sore and 18 normal throats; enteric bacilli in 1 of each; Candida and Neisseria in 2 sore throats each. All of the 33 hemolytic Haemophilus isolates identified to species were H. parahaemolyticus. All were sensitive in vitro to chloramphenicol, erythromycin, and tetracycline; 30 were sensitive to ampicillin and 30 to penicillin, 26 to novobiocin, and 12 to methicillin. H. influenzae, H. parainfluenzae, and H. haemolyticus are indistinguishable by Gram stain morphology, but H. parahaemolyticus is larger than the other three. Hemolytic and nonhemolytic species are indistinguishable by colonial morphology or by nutritional requirements; only hemolysis gives positive differentiation. Nevertheless, only rarely would this be of clinical importance. H. parahaemolyticus apparently may cause pharyngitis, but it is almost always susceptible to penicillin and rarely if ever causes sequelae.

Anti-Bacterial Agents↗

PubMed1990

[Slime production, hemolysis and proteolysis in coagulase-negative staphylococci isolated in hemoculture from humans].

Of 162 strain of coagulase negative staphylococci isolated from haemocultures most frequently the following were identified: S. epidermidis (56.8%), S. haemolyticus (17.3%) and S. hominis (14.2%). By means of the STAPHYtest first 138 strains were assessed (85.2%). Mucus formation was proved in 26 strains (16.0%) of six different species. Haemolytic activity was present in 131 strains (80.9%) in seven species, significantly more frequently in S. haemolyticus. Proteolytic activity was displayed by 118 strains (72.8%) of all nine identified species, significantly more often in S. epidermidis. Mucus and protease formation, haemolysin and protease formation as well as simultaneous formation of all three factors was observed most frequently in S. epidermidis. Strains of S. epidermidis thus have more frequently signs considered virulence factors than strains of the other species of coagulase negative staphylococci.

Coagulase↗

PubMed1993

[Action of teicoplanin on coagulase negative staphylococci in hospital units of the hospital Hôtel-Dieu in Paris].

Teicoplanin, a glycopeptide antibiotic, is active against Staphylococci, with the exception of some strains of coagulase negative Staphylococci (SCN). Determination of the in vitro activity of teicoplanin by standard disk methodology is not sufficient, and has to be confirmed by the determination of the minimal inhibitory concentration (MIC) for all strains presenting an inhibition zone diameter below 17 mm. We have studied during four months, the susceptibility of SCN to teicoplanin isolated from different units of the hospital, and in particular from the haematology unit (HU). 186 strains were isolated, 35 p. cent from HU and 65 p. cent from the other units of the hospital. All strains belonged to 11 species: 136 S. epidermidis, 14 S. haemolyticus, 8 S. lugdunensis, 5 S. warneri, 4 S. saprophyticus, 3 S. sciuri, 3 hominis, 2 S. chromogens, 2 xylosus, 2 S. cohnii and 1 S. schleiferi. Twenty five strains out of 186 (13.4%) presented a MIC of 8 or 16 mg/l (MIC verified by the agar dilution method): 7 S. haemolyticus, 16 S. epidermidis, 1 S. warneri et 1 S. capitis. During this study SCN resistant to teicoplanin were never isolated. Twelve out of 25 came from the HU, which correspond to 18 p. cent of the isolated strains in this unit. This result was not significantly different, compared to that of the other units.

Dose-Response Relationship, Drug↗