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At least 595 records · Page 33Linked to original sources
PubMed1989

Methicillin resistance in staphylococci: an evaluation of conditions for detection.

Ninety-four strains of coagulase positive staphylococci and 73 strains of coagulase negative staphylococci were tested for their susceptibility to methicillin, using agar dilution and disc diffusion techniques with Diagnostic Sensitivity Test agar (DST) and DST supplemented with salt, incubated at 30 degrees C and 37 degrees C. Disc diffusion on salt-incorporated DST at 30 degrees C was most reliable for detecting methicillin resistance in both types of staphylococci. The agar dilution methods were particularly poor for detecting resistance with coagulase negative staphylococci. The simultaneous testing of coagulase positive and negative staphylococci by this method indicated the need for both DST and salt-incorporated DST agar plates, incubated at 30 degrees C. However, sensitive strains should still be tested by disc diffusion for confirmation.

Coagulase↗
PubMed1979

Antibiotic-resistance transfer in Yersinia enterocolitica.

Most clinical isolates of Yersinia enterocolitica have been reported to be inhibited by a wide variety of antimicrobial agents. This finding indicates that Y. enterocolitica infrequently acquires resistance by gene transfer from other bacteria in nature. In the present study the authors examined whether Y. enterocolitica has the potential for acquiring antibiotic resistance from another organism in vitro. Mixed cultures of multiple-antibiotic-resistant Escherichia coli and a sensitive Y. enterocolitica yielded resistant Y. enterocolitica. Resistance to at least four drugs was transferred at a frequency of approximately 10(-7) transconjugants per donor. The newly resistant Y. enterocolitica transferred resistance to a sensitive E. coli at a slightly higher frequency. Resistance to at least one antibiotic was transferred to all five strains of Y. enterocolitica tested.

Drug Resistance, Microbial↗
PubMed2006

[Modern diagnosis of tuberculosis].

Microscopic examination of sputum smears (search for acid-fast bacilli or AFB) is the most rapid procedure for diagnosis of contagious tuberculosis. Gene amplification is not yet reliable for direct detection of M. tuberculosis in clinical specimens that are AFB smear-negative. Culture (3 to 8 weeks on Lowenstein-Jensen medium or 1 to 4 weeks in liquid media) remains essential to identify AFB and conduct antibiotic susceptibility testing. AFB from culture can be identified in a few hours by molecular approaches with specific DNA probes. Results of susceptibility testing, even in liquid media, are not available until 2 to 4 weeks after the recovery of specimens, although mutations of the rpoB and katG 315 genes, which confer resistance to rifampin and isoniazid, can be detected within hours by molecular hybridization with specific probes fixed on strips. Immunologic tests that measure the interferon gamma produced by sensitized lymphocytes are promising tools for the diagnosis of latent tuberculosis.

Adenosine Deaminase↗
PubMed1990

The assessment of the bactericidal activity of surface disinfectants. II. Two other practical tests.

The Dutch quantitative carrier test (QCT) prescribes the rinsing technique for counting the surviving bacteria after disinfection. This method is compared with the Leuven test, which uses the impression technique in order to determine the survival on the disinfected surfaces, and with a novel quantitative surface disinfection test (QSDT). The QSDT combines the preparatory and disinfection phase of the Leuven test with the postexposure rinsing technique of the QCT. The results of the three tests correlate very well as is shown by Kendall's rank correlation test. The QCT and the Leuven test yield equivalent results: neither the median of the results, nor the paired results apart differ statistically for the same exposure time of 30 min. On the contrary the results of the novel QSDT differ in a statistically significant way from those of both other techniques, but the QSDT is more severe than the QCT and the Leuven test in the case of Staphylococcus aureus, whereas in the case of Pseudomonas aeruginosa it is the less severe one. This phenomenon can hardly be explained and emphasizes the importance of the resuscitation of sublethally damaged germs in the postexposure phase of testing.

Colony Count, Microbial↗
PubMed1978

[Susceptibility testing of anaerobes (author's transl)].

The methodology of susceptibility testing of anaerobes has not yet been standardized and many individual test methods are in use. Among the factors which may influence the outcome of susceptibility tests are test organisms, antimicrobials and methods of susceptibility testing. Comparative studies have shown that the density of the inoculum largely influences the MICs of sulphonamides and certain other antimicrobials. In testing susceptibility of anaerobes to doxycycline, the MICs determined by agar dilution tests were 2--4--8 times the MICs obtained by broth dilution technique. However, with certain cephalosporins and beta-lactamase-producing strains of Bacteroides fragilis and other Bacteroides species the MICs obtained by the two methods differed by four to five dilution steps. Judging by the broth dilution test, the majority of the beta-lactamase-producing Bacteroides strains would be classified as resistant, whereas with beta-lactamase-negative strains of Sphaerophorus varius the broth dilution test gave much lower MICs than the agar dilution technique. These findings pose the rather embarrassing problem as to whether strains are to be regarded as resistant or sensitive. As is demonstrated by lack of stochastic linearity and/or low correlation coefficients, the results of standardized anaerobic agar diffusion tests are for the most part not correlated to MICs determined by either method of quantitative susceptibility testing.

Anaerobiosis↗
PubMedDate not supplied

[Pseudomonas aeruginosa III. Identification of strains isolated from blue foxes (Alopex lagopus) in a Danish fur farm (author's transl)].

The technique of determining bacterial strains as Ps. aeruginosa is described. It was attempted to base this technique upon well-defined commercial preparations, so as to afford a possibility for comparative studies. 261 strains presumed to be Ps. aeruginosa were isolated from sick and healthy blue foxes and their watering troughs. 244 of the strains could be subjected to detailed bacteriological study (Table I a, b, c, fig. 1) in addition to the demonstration of pigment (pyocyanin and fluorescin). All 244 proved to be Ps. aeruginosa. Among them 10 non-pigment-producing strains were characterized as "atypical" Ps. aeruginosa strains. The determination of the genus was supported by the results of the sensitivity tests (Table II).

Animals↗
PubMed2003

Screening for methicillin resistance in Staphylococcus aureus and coagulase-negative staphylococci: an evaluation of three selective media and Mastalex-MRSA latex agglutination.

Laboratory confirmation of MRSA is important for the implementation of infection control; conventional screening culture methods take up to five days for confirmation. The purpose of this study is to ascertain the efficiency of three selective media for growth of methicillin-resistant Staphylococcus aureus (MRSA) before and after enrichment in salt broth, and to evaluate the Mastalex-MRSA latex agglutination kit for detection of methicillin resistance. Screening swabs were collected from 63 patients, yielding 125 S. aureus isolates and 40 coagulase-negative staphylococcus (CNS) isolates. Selective media used were mannitol salt agar (MSA), Baird-Parker agar with ciprofloxacin (BPC) and bromocresol purple (BCPA). Polymerase chain reaction (PCR) for mecA gene detection was used as the reference standard for evaluation of the Mastalex-MRSA assay, which was also evaluated on colonies of S. aureus from the selective media. No significant difference was found in efficiency of MRSA isolation among the selective media. Pre-enrichment in the salt broth did not enhance isolation of MRSA. Methicillin-sensitive S. aureus and CNS were significantly inhibited in all selective media (P<0.05). Only BPC significantly selected out methicillin-resistant CNS (P<0.01). Mastalex-MRSA was 97% specific and sensitive for the detection of MRSA. It was 65% sensitive and 100% specific in detecting methicillin resistance in CNS. In conclusion, all selective media performed equally well (MRSA isolation rate of approximately 80%). Mastalex-MRSA provided rapid and reliable detection of MRSA from selective media, reducing the time required for confirmation of this organism.

Agglutination Tests↗
PubMed1983

[Identification and sensitivity of Streptococci to antibiotics].

In the first part of this research, the author accentuates the quick and easy identification of the Streptococcus by means of Latex-test, testing at the same time the bacitracin. In the second part, the antibiotic sensitivity is tested on 354 strains of Streptococci.

Anti-Bacterial Agents↗