Chlamydia psittaci is an obligate intracellular bacterium that can cause significant disease among a broad range of hosts. In humans, this organism may cause psittacosis, a respiratory disease that can spread to involve multiple organs, and in rare untreated cases may be fatal. There are ten known genotypes based on sequencing the major outer membrane protein gene, ompA, of C. psittaci. Each genotype has overlapping host preferences and virulence characteristics. Recent studies have compared C. psittaci among other members of the Chlamydiaceae family and showed that this species frequently switches hosts and has undergone multiple genomic rearrangements. In this study, we sequenced five genomes of C. psittaci strains representing four genotypes, A, B, D and E. Due to the known association of the type III secretion system (T3SS) and polymorphic outer membrane proteins (pmps) with host tropism and virulence potential, we performed a comparative analysis of these elements among these five strains along with a representative genome from each of the remaining six genotypes previously sequenced. We found significant genetic variation in the pmps and T3SS genes that may partially explain differences noted in C. psittaci host infection and disease.

Strains of Neisseria gonorrhoeae with mosaic penA genes bearing novel point mutations in penA have been isolated from ceftriaxone treatment failures. Such isolates exhibit significantly higher MIC values to third generation cephalosporins. Here we report the in vitro isolation two mutants with elevated MICs to cephalosporins. The first possesses a point mutation in the transpeptidase region of the mosaic penA gene, and the second contains an insertion mutation in pilQ.

Microorganisms may colonize needleless connectors (NCs) on intravascular catheters, forming biofilms and predisposing patients to catheter- associated infection (CAI). Standard and silver-coated NCs were collected from catheterized intensive care unit patients to characterize biofilm formation using culture-dependent and culture-independent methods and to investigate association between NC usage and biofilm characteristics. Viable microorganisms were detected by plate count (PC) from 46% of standard and 59% of silver-coated NCs (p=0.11). There were no significant associations (p>0.05, chi-squared test) between catheter type, side of catheter placement, number of catheter lumens, site of catheter placement, or NC duration, and positive NC. There was an association (p=0.04, chi-squared test) between infusion type and positive standard NCs. Viable microorganisms exhibiting intracellular esterase activity were detected on >90% of both NC types (p=0.751), suggesting that a large percentage of organisms were not culturable using the conditions provided in this study. Amplification of the 16S ribosomal RNA gene from selected NCs provided a substantially larger number of operational taxonomic units per NC than PC (26-43 vs 1-4), suggesting that culture-dependent methods may substantially underestimate microbial diversity on NCs. NC bacterial communities were clustered by patient and venous access type and may reflect the composition of the patient's local microbiome but may also contain organisms from the healthcare environment. NCs provide a portal of entry for a wide diversity of opportunistic pathogens to colonize the catheter lumen, forming a biofilm and increasing the potential for CAI, highlighting the importance of catheter maintenance practices to reduce microbial contamination.