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- Petersson, A C, et al.
(författare)
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Evaluation of four qualitative methods for detection of beta-lactamase production in Staphylococcus and Micrococcus species
- 1989
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Ingår i: European Journal of Clinical Microbiology & Infectious Diseases. - 1435-4373. ; 8:11, s. 962-967
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Tidskriftsartikel (refereegranskat)abstract
- Four qualitative methods for the detection of beta-lactamase production in Staphylococcus and Micrococcus species were evaluated and compared with a quantitative macroiodometric reference method. The disc diffusion test with penicillin G and the cloverleaf method could not separate beta-lactamase-positive from beta-lactamase-negative strains. Two applications of the chromogenic cephalosporin test, using uninduced strains and strains grown on blood agar plates, gave a large number of false negative and false positive results. False negative reactions were most common among uninduced strains, while the false positive reactions were most often recorded for Staphylococcus saprophyticus. A high degree of efficiency was recorded for the nitrocefin spot test, using induced strains grown on antibiotic susceptibility agar, and for the starch-iodine plate method. The starch-iodine plate with methicillin as inducer gave the most reliable results.
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| 2. |
- Petersson, A C, et al.
(författare)
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Identification of mecA-related oxacillin resistance in staphylococci by the E test and the broth microdilution method
- 1996
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Ingår i: Journal of Antimicrobial Chemotherapy. - : Oxford University Press (OUP). - 1460-2091 .- 0305-7453. ; 37:3, s. 445-456
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Tidskriftsartikel (refereegranskat)abstract
- A set of 165 strains of different staphylococcal species, 67 Staphylococcus aureus, 71 novobiocin-sensitive coagulase-negative staphylococci (CNS) and 27 novobiocin-resistant CNS was used. The oxacillin and methicillin MICs were recorded after 24 and 42 h of incubation at 35 degrees C and at 30 degrees C. Significantly higher MICs were recorded at 30 degrees C compared with 35 degrees C. While a poor discrimination between mecA-positive and mecA-negative strains was obtained with methicillin, the oxacillin MICs enabled identification of resistant strains under certain conditions. The distribution of MICs differed between the three groups of species. Separation of uninduced mecA-positive (> or = 4.0 mg oxacillin/L) and mecA-negative (< or = 2.0 mg oxacillin/L) strains of S. aureus was only achieved with the E test and after 42 h of incubation. Oxacillin-induction yielded higher MICs for mecA-positive strains of S. aureus, and a separation from mecA-negative strains was achieved with the E test after 24 h and with the broth microdilution method after 42 h. Separation of mecA-positive and mecA-negative strains of novobiocin-sensitive CNS required agar supplemented with 5% blood, incubation of MIC trays and E test for 42 h, and species-specific oxacillin MIC breakpoints (S < or = 0.5 mg/L and R > or = 1.0 mg/L). The mecA-positive and mecA-negative strains of novobiocin-resistant CNS were clearly separated after 24 h of incubation by either method.
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| 6. |
- Schalén, Lucyna, et al.
(författare)
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High isolation rate of Branhamella catarrhalis from the nasopharynx in adults with acute laryngitis
- 1980
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Ingår i: Scandinavian Journal of Infectious Diseases. - 1651-1980. ; 12:4, s. 277-280
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Tidskriftsartikel (refereegranskat)abstract
- Branhamella catarrhalis was isolated from the nasopharynx in 55% of 40 noncompromised adult patients suffering from acute laryngitis. Diplococcus pneumoniae and haemophilus influenzae were found in another 5 and 8%, respectively; one patient had group A streptococci in the throat specimen. In 90% of the patients the laryngitis complaints were preceded by symptoms of an acute respiratory tract infection. Two of the patients with B. catarrhalis showed a significant titre conversion against influenza B and parainfluenza type e virus, respectively. Attempts to isolate virus failed in all cases. The results indicate that B. catarrhalis, known to cause acute otitis media in small children and respiratory tract infections in adult compromised hosts, may be involved in the etiology of acute laryngitis in otherwise healthy adults.
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