Identification of bacteria using volatile organic compounds.

The rapid diagnosis of respiratory infections has always been an important goal for medical professionals, because rapid and accurate diagnosis leads to proper and timely treatment, and consequently, reduces the costs of incorrect and long-term treatments, and antibiotic resistance. The present study was conducted with the aim of detecting volatile organic compounds (VOCs) in three bacteria: Pseudomonas aeruginosa, Acinetobacter baumannii, Klebsiella pneumoniae. Headspace of the studied bacteria, after separately culturing in two types of liquid medium in three different time-periods, was extracted by solid phase microextraction and analysed by gas chromatography mass spectrometry The analysis results of the VOCs produced by the studied bacteria indicate that some VOCs are common and some are unique in each bacterium. 1-penten-3-ol, levomenthol, and 2-octyl-1-ol for P. aeruginosa, cyclohexene, 4-ethenyl, and cis-Dihydro-α-terpinyl acetate for A. baumannii and 1,3-butadiene, butyraldehyde, longifolene, octyl acetate, tridecanol, dodecenal, (E)-2-hexyl ester, butanoic acid, and 5,5-dodecadinyl-1 12-diol for K. pneumoniae were identified as unique VOCs for each bacterium. Finally, it can be said that an accurate and rapid bacterial detection method can be achieved by using a tool that can detect bacterial VOCs. However, more studies are needed to design a tool for which all aspects have been assessed, so that it can give us a more complete pattern for the use of these compounds as biomarkers.

Antibiotic resistance is linked to carriage of papC and iutA virulence genes and phylogenetic group D background in commensal and uropathogenic Escherichia coli from infants and young children.

P fimbriae, enabling adherence to colonic and urinary epithelium, and aerobactin, an iron sequestering system, are both colonization factors in the human colon and virulence factors for urinary tract infection. The colonic microbiota is suggested to be a site suitable for the transfer of antibiotic resistance genes. We investigated whether phenotypic resistance to antibiotics in commensal and uropathogenic Escherichia coli from infants and young children is associated with carriage of virulence genes and to phylogenetic group origin and, in the case of fecal strains, to persistence in the gut and fecal population levels. The commensal strains (n = 272) were derived from a birth cohort study, while the urinary isolates (n = 205) were derived from outpatient clinics. Each strain was assessed for phenotypic antibiotic resistance and for carriage of virulence genes (fimA, papC, sfaD/E, hlyA, iutA, kfiC, and neuB), phylogenetic group (A, B1, B2, or D), and markers of particular virulent clones (CGA-D-ST69, O15:H1-D-ST393, and O25b:H4-B2-ST131). Resistance to ampicillin, tetracycline, and trimethoprim was most prevalent. Multivariate analysis showed that resistance to any antibiotic was significantly associated with carriage of genes encoding P fimbriae (papC) and aerobactin (iutA), and a phylogenetic group D origin. Neither fecal population numbers nor the capacity for long-term persistence in the gut were related to antibiotic resistance among fecal strains. Our study confirms the importance of phylogenetic group D origin for antibiotic resistance in E. coli and identifies the virulence genes papC and iutA as determinants of antibiotic resistance. The reason for the latter association is currently unclear.

Fast size-determination of intact bacterial plasmids using nanofluidic channels.

We demonstrate how nanofluidic channels can be used as a tool to rapidly determine the number and sizes of plasmids in bacterial isolates. Each step can be automated at low cost, opening up opportunities for general use in microbiology labs.

Adhesion of meticillin-resistant Staphylococcus aureus to DACC-coated dressings.

OBJECTIVE: The aim of this in vitro study was to demonstrate the binding capacity of multiple meticillin-resistant Staphylococcus aureus (MRSA) strains and compare the binding capacity to meticillin-sensitive Staphylococcus aureus. METHOD: The binding of Staphylococcus aureus to a surface was assessed by bioluminescent monitoring of the bacterial ATP levels. This assay can be used as an in vitro diagnostic model for bacteria binding in a critically colonised wound. RESULTS: Eleven strains of Staphylococcus aureus were examined including MRSA, all of which efficiently and equally adhered to the dialkyl carbamoyl chloride (DACC)-coated dressing (Sorbact; Abigo Medical AB). The binding capacity was all in the same range 0.7-2.9 × 106 CFU/cm². regardless of the antibiotic resistance properties of the specific strain. CONCLUSION: The decrease of wound bioburden of Staphylococcus aureus including MRSA is the result of the high binding capacity shown in this study and by earlier data. The findings in this study strengthen the held view that development of antibiotic resistance has minimal impact on the surface structures of the microorganisms in wounds.

Increase of peripheral blood TCD8+ cells in women with recurrent miscarriage.

Recurrent miscarriage (RM) is one of the most prevalent reproductive problems faced by couples that may affect as many as 2% of women in reproductive age. The causes of its abnormality have attracted the attention of many researchers. We aim to determine the different T-cell subsets in women with RM and normal control. In this prospective case-control study, peripheral blood was taken from women with RM (n = 25) and normal women (n = 17), during the mid-luteal phase. The percentage of CD3, CD3(+)CD4(+), CD3(+)CD8(+) markers and also CD4/CD8 ratio was detected in the patients and control group by flow cytometry. The proportion of TCD8(+) was significantly higher in RM women compared with the control group (p < 0.05). However, there was no statistical difference in percentage of total TCD3(+) and TCD4(+) cells between the RM and control women. Also, the CD4/CD8 ratio was lower in the RM women compared with the control women. These observations support the concept that increase of TCD8(+) lymphocytes could be involved in the aetiology of RM.

Shift of CTX-M genotypes has determined the increased prevalence of extended-spectrum ß-lactamase-producing Escherichia coli in south-western Sweden.

The prevalence of Escherichia coli producing extended-spectrum ß-lactamases (ESBLs) markedly increased during 2004-2008 in south-western Sweden, with a greater increase in urinary isolates in hospitals (0.2-2.5%) than in the community (0.2-1.6%). ESBLs of genotype CTX-M predominated, with a significant (p <0.02) shift from the CTX-M-9 to CTX-M-1 phylogroup occurring among urinary ESBL-producing E. coli isolated early (n = 41) as compared with late (n = 221) in the study period. The increase in ESBL-producing E. coli was polyclonal, and only partly attributable to an increase (0-24%) in the number of O25b-ST131 isolates carrying CTX-M-15. The increase was prominent in men and in elderly patients, and warrants continued surveillance.