Whole Genome Analysis of Epidemiologically Closely Related <i>Staphylococcus aureus</i> Isolates

<div><p>The change of the bacteria from colonizers to pathogens is accompanied by a drastic change in expression profiles. These changes may be due to environmental signals or to mutational changes. We therefore compared the whole genome sequences of four sets of <i>S. aureus</i> isolates. Three sets were from the same patients. The isolates of each pair (S1800/S1805, S2396/S2395, S2398/S2397, an isolate from colonization and an isolate from infection, respectively) were obtained within <30 days of each other and the isolate from infection caused skin infections. The isolates were then compared for differences in gene content and SNPs. In addition, a set of isolates from a colonized pig and a farmer from the same farm at the same time (S0462 and S0460) were analyzed. The isolates pair S1800/S1805 showed a difference in a prophage, but these are easily lost or acquired. However, S1805 contained an integrative conjugative element not present in S1800. In addition, 92 SNPs were present in a variety of genes and the isolates S1800 and S1805 were not considered a pair. Between S2395/S2396 two SNPs were present: one was in an intergenic region and one was a synonymous mutation in a putative membrane protein. Between S2397/S2398 only one synonymous mutation in a putative lipoprotein was found. The two farm isolates were very similar and showed 12 SNPs in genes that belong to a number of different functional categories. However, we cannot pinpoint any gene that explains the change from carrier status to infection. The data indicate that differences between the isolate from infection and the colonizing isolate for S2395/S2396 and S2397/S2398 exist as well as between isolates from different hosts, but S1800/S1805 are not clonal. </p> </div

Characteristics of <i>Staphylococcus aureus</i> CC398 strains isolated in Central Greece.

<p>CA: community–associated; HA: hospital-associated; ST: sequence type; SSTI: skin and soft tissue infection; P: penicillin; FOS: fosfomycin; E: erythromycin; CC: clindamycin; SXT: sulfamethoxazole-trimethoprim; RA: rifampicin; OX: oxacillin.</p><p>*All isolates were susceptible to vancomycin, teicoplanin, fusidic acid, linezolid, daptomycin, tobramycin, gentamicin, levofloxacin, moxifloxacin.</p><p>Characteristics of <i>Staphylococcus aureus</i> CC398 strains isolated in Central Greece.</p

Study flow chart for each study period.

<p>CDI: <i>Clostridium difficile</i> infection</p

Cox regression analysis of variables associated with time until development of CDI.

<p>Cox regression analysis of variables associated with time until development of CDI.</p

Primary and secondary variables of point-prevalence of each phase of the study.

<p>Primary and secondary variables of point-prevalence of each phase of the study.</p

Impact of solid tumor malignancy and Charlson’s Comorbidity Index score more than 6 on the time until development of CDI.

<p>Impact of solid tumor malignancy and Charlson’s Comorbidity Index score more than 6 on the time until development of CDI.</p

Comparative characteristics of patients with diarrhea with and without <i>Clostridium difficile</i> infection (CDI).

<p>Comparative characteristics of patients with diarrhea with and without <i>Clostridium difficile</i> infection (CDI).</p

Logistic regression analysis of risk factors related to <i>Clostridium difficile</i> infection among patients with diarrhea.

<p>Logistic regression analysis of risk factors related to <i>Clostridium difficile</i> infection among patients with diarrhea.</p