Urine samples constitute a large proportion of samples tested in clinical microbiology laboratories. Culturing of the samples is fairly time-and labor-consuming, and most of the samples will yield no growth or insignificant growth. We analyzed the feasibility of the flow cytometry-based UF-500i instrument (Sysmex, Japan) to screen out urine samples with no growth or insignificant growth and reduce the number of samples to be cultured. A total of 1,094 urine specimens sent to our laboratory for culture during 4 months in the spring of 2009 in Lahti, Finland, were included in the study. After culture, all samples were analyzed with the Sysmex UF-500i for bacterial and leukocyte (white blood cell [WBC]) counts. Youden index and closest (0,1) methods were used to determine the cutoff values for bacterial and WBC counts in culture-positive and -negative groups. By flow cytometry, samples considered positive for UTI in culture had bacterial and WBC values that were significantly higher than those for samples considered negative. The flow cytometric screening worked best when both bacterial counts and WBC counts were used with age-and gender-specific cutoff values for all patient groups, excluding patients with urological disease or anomaly. By use of these cutoff values, 5/167 (3.0%) of culture-positive samples were missed by UF-500i and the percentage of samples that did not need to be cultured was 64.5%. Use of the UF-500i instrument is a reliable method for screening out a major part of the UTI-negative samples, significantly diminishing the amount of work required in the microbiology laboratory.Urinary tract infections (UTIs) are among the most common infections treated by community health care centers and hospitals (5,6,13,19,24). In Finland, urinary tract infections account for approximately 6% of all infectious disease diagnoses in primary care (20) and urine samples constitute a large proportion of the samples tested in clinical microbiology laboratories (13,18,24). The gold standard for UTI diagnosis is bacterial culture, which is based on bacterial counts and identification. Culturing of the samples is fairly time-and laborconsuming, and most of the samples yield no growth or insignificant growth (10,15,22,24). In order to improve the efficiency of handling of the urine samples, methods for screening out the culture-negative samples from the culture-positive samples have been developed. Chemical screening with strips for nitrite, pH, leukocytes, erythrocytes, albumin, and glucose is widely used (17,18,22,23), but a meta-analysis of the literature (4) has shown that the method is insensitive and is suitable as a rule-out test only when both nitrite and leukocyteesterase are negative. Cells, particles, and microorganisms in urine can be examined by microscopic-urine-sediment analysis, but this method is time-consuming, labor-intensive, and sensitive to interobserver variability (2,7,8,10,12,21).Pyuria with bacteria predicts bladder infection better than the presence of bacteria alone, and therefore, a screenin...

In this study, the performances of two matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) systems, MALDI Biotyper (Bruker Daltonics) and VITEK MS (bioMérieux), were evaluated in the identification of viridans group streptococci. Two collections of isolates were tested with both methods. From a panel of type collection strains (n = 54), MALDI Biotyper gave correct species-level identification for 51/54 (94 %) strains and 37/54 (69 %) strains for the VITEK MS in vitro diagnostic (IVD) method. Additionally, a collection of blood cultures isolates which had been characterized earlier with partial sequencing of 16S rRNA (n = 97) was analyzed. MALDI Biotyper classified 89 % and VITEK MS 93 % of these correctly to the group level. Comparison of species-level identification from the blood culture collection was possible for 36 strains. MALDI Biotyper identified 75 % and VITEK MS 97 % of these strains consistently. Among the clinical isolates, MALDI Biotyper misidentified 36 strains as Streptococcus pneumoniae. Nevertheless, our results suggest that the current MALDI-TOF methods are a good alternative for the identification of viridans streptococci and do perform as well as or better than commercial phenotypical methods.

Strain PCP-I, which was isolated from a pentachlorophenol-mineralizing mixed culture, had the following characteristics of the actinomycetes assigned to the genus Rhodococcus: DL-diaminopimelic acid, arabinose, and galactose as cell wall constituents; major menaquinone with nine isoprenoid units and one hydrogenated double bond (MK-9Hz); mycolic acids containing 33 to 43 carbon atoms; and a marked rod-to-coccus cycle during growth. None of the previously described species of Rhodococcus contains both MK-9H2 and mycolic acids of this size, and, unlike other rhodococci, strain PCP-I utilizes rhamnose, inositol, and sorbitol. Based on these properties, we believe that strain PCP-I represents a new Rhodococcus species. We propose the name Rhodococcus chlorophenolicus for this new species because of its ability to degrade several chlorophenols. The type strain is strain PCP-I (= DSM 43826).The classification of actinomycetes containing mycolic acids was unsatisfactory prior to the use of chemical characteristics as taxonomic markers. Chemotaxonomy has provided a new framework for the classification of these organisms, and simple methods have been developed for routine analysis (18,35).Cell wall analysis is a useful tool in distinguishing members of the genera Corynebacterium, Caseobacter, Rhodococcus, Nocardia, and Mycobacterium from other actinomycetes. In representatives of these genera the cell walls contain meso-diaminopimelic acid, arabinose, and galactose (12,25,26), as well as mycolic acids (long-chain 2-alkyl-branched 3-hydroxy acids). In mycobacteria, mycolic acids are large and complex and are not extractable in ethanol-diethyl ether (22). Corynebacterium, Rhodococcus, and Nocardia species contain smaller and easily extractable (free) mycolic acids (22,29,33).In different bacterial species menaquinones (2-methyl-3-polyprenyl-1,4-naphthoquinones) vary in the number of isoprenoid units and in the degree of hydrogenation. This can be used as a classifying marker (8). The menaquinone compositions of Nocardia species (except Nocardia amarae) (21) are different from the menaquinone compositions of Corynebacterium, Rhodococcus, and Mycobacterium (4, 7,10,11,43).Rhodococci undergo rod-to-coccus variation during the growth cycle (23,27). This kind of morphological variation does not occur in the true corynebacteria (23, 27). In contrast, norcardiae form mycelia which fragment, whereas mycobacteria usually form curved or straight rods which occasionally branch (18). However, because of dissimilarities in cultural conditions, the morphological studies described in the literature are seldom comparable.In this paper we describe a novel mycolic acid-containing actinomycete. The type and only strain, strain PCP-I, mineralizes pentachlorophenol and degrades many other chlorophenols as well (Apajalahti and Salkinoja-Salonen, submitted for publication). MATERIALS AND METHODSCultures. The strains which we used are listed in Table 1. The original isolate, strain PCP-I, was obtained from a * Corresponding author.pentachlorophen...

The use of low-content ampicillin and co-amoxiclav discs is recommended for the susceptibility testing of H. influenzae. Interpretative criteria of S > or = 17 mm and R < or = 13 mm for both discs are suggested.

The association between trimethoprim-sulfamethoxazole use and resistance among the major respiratory tract pathogens was investigated by comparing regional consumption of the drug to regional resistance in the following year in 21 central hospital districts in Finland. A total of 23,530 Streptococcus pneumoniae isolates, 28,320 Haemophilus influenzae isolates, and 14,138 Moraxella catarrhalis isolates were tested for trimethoprim-sulfamethoxazole susceptibility during the study period (1998)(1999)(2000)(2001)(2002)(2003)(2004). Among the S. pneumoniae isolates, a statistically significant connection was found between regional consumption and resistance. No statistically significant connection was found between regional trimethoprim-sulfamethoxazole use and resistance among H. influenzae and M. catarrhalis isolates. According to our results, it seems that only in pneumococci can the development of trimethoprimsulfamethoxazole resistance be influenced by restricting its use. However, trimethoprim-sulfamethoxazole remains an important antimicrobial agent because of its reasonable price. Hence, resistance to trimethoprim-sulfamethoxazole among these pathogens needs continuous monitoring.Sulfonamides were the first class of antimicrobial agents introduced into clinical use in 1935. Trimethoprim (TMP) was introduced in 1962, and the combination trimethoprim-sulfamethoxazole (SXT) was brought into clinical use in 1968. The antibacterial spectrum of the combination is directed at Escherichia coli, other species in the Enterobacteriaceae family, Staphylococcus aureus, Staphylococcus saprophyticus, and the principal respiratory tract pathogens Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis.Hence, the most important fields of use of SXT combinations are in the treatment of urinary tract infections and upper respiratory tract infections. According to a point prevalence study conducted in the Finnish primary health care system, by indication, 81% of all SXT prescriptions were for respiratory tract infections and 15% were for urinary tract infections (21). Since it is a relatively inexpensive drug, this combination has been used widely in developing countries. There are also a few special indications for SXT use, such as the prophylaxis of Pneumocystis carinii infections among AIDS patients and the treatment of infections caused by Stenotrophomonas maltophilia (13).Emerging resistance among the major respiratory tract pathogens S. pneumoniae, H. influenzae, and M. catarrhalis has undoubtedly decreased the use of SXT. This resistance, however, varies worldwide. In the late 1990s, 31.9 to 88.6% of European and 24.2 to 89.4% of Asian S. pneumoniae isolates were susceptible to SXT. Among H. influenzae strains, a similar variation was noticed (22). According to a recent report from the United States, resistance among pneumococci is decreasing after peaking in 1999-2000 (9). A very small proportion of M. catarrhalis isolates, 0.1 to 2.6%, in the SENTRY surveillance program in 1997-1999 (12) showed resi...