Mycoplasma bovis is a major bovine pathogen associated with bovine respiratory disease complex and is responsible for substantial economic losses worldwide. M. bovis is also associated with other clinical presentations in cattle, including mastitis, otitis, arthritis, and reproductive disorders. To gain a better understanding of the genetic diversity of this pathogen, a multilocus sequence typing (MLST) scheme was developed and applied to the characterization of 137 M. bovis isolates from diverse geographical origins, obtained from healthy or clinically infected cattle. After in silico analysis, a final set of 7 housekeeping genes was selected (dnaA, metS, recA, tufA, atpA, rpoD, and tkt). MLST analysis demonstrated the presence of 35 different sequence types (STs) distributed in two main clonal complexes (CCs), defined at the double-locus variant level, namely, CC1, which included most of the British and German isolates, and CC2, which was a more heterogeneous and geographically distant group of isolates, including European, Asian, and Australian samples. Index of association analysis confirmed the clonal nature of the investigated M. bovis population, based on MLST data. This scheme has demonstrated high discriminatory power, with the analysis showing the presence of genetically distant and divergent clusters of isolates predominantly associated with geographical origins.M ycoplasma diseases cause substantial economic losses, particularly in intensively farmed cattle production systems worldwide, as a result of poor growth, morbidity, and deaths, as well as the costs associated with increased control and prophylactic measures. Mycoplasma bovis has increasingly been recognized as one of the main pathogens involved in the bovine respiratory disease complex, on its own or in association with other respiratory pathogens (1). M. bovis can also be found in association with mastitis, in which outbreaks can affect more than 20% of the cows in a herd, regardless of the stage of lactation, and infections are usually refractory to treatment. Arthritis and otitis have also been associated with M. bovis, usually appearing once pneumonia or mastitis is already established in the herd (1, 2). The control of M. bovis infections relies strongly on antimicrobial therapy, which has variable success rates in the field (3). Vaccination has been used in the early stages of cattle development and is mostly based on autogenous vaccines, which limits their use and the potential for widespread control of M. bovis infections (3).Taking into consideration the limited tools available for M. bovis disease management, the development of a dependable molecular typing scheme able to offer robust and reproducible epidemiological information would provide a valuable addition to control measures targeting this pathogen. M. bovis isolates have been characterized previously using multiple molecular typing methods, including amplified fragment length polymorphism (AFLP) analysis (4), random amplified polymorphic DNA (RAPD) analysis (5), pulsed-fiel...

With the rising antibiotic resistance of many bacterial species, alternative treatments are necessary to combat infectious diseases. The World Health Organization and the US Centres for Disease Control and Prevention have warned that some infections, such as those from Neisseria gonorrhoeae, may be untreatable within a few years. One avenue of exploration is the use of antimicrobial fatty acids and their derivatives for therapeutic prevention or treatment of bacterial infections. Several studies have explored the activity of fatty acids and their derivatives, including monoglycerides against a variety of bacterial species. These are reviewed here, assessing the antimicrobial properties that have been demonstrated and the feasibility of therapeutic applications.

Contagious caprine pleuropneumonia (CCPP), caused by Mycoplasma capricolum subsp. capripneumoniae, is a serious OIE-listed disease affecting goats in the Middle East, north and east Africa and Asia. Mortality and morbidity rates can be as high as 60% and 90%, respectively, when the disease first enters a territory, invariably through carrier animals. Recent detections of CCPP in Pakistan and Tajikistan are probably the result of improved diagnosis as the disease has been suspected there for many years, while those in Thrace in 2003 and Mauritius in 2009 represent new outbreaks. CCPP was thought to be highly host specific until recent outbreaks in wildlife species including gazelles and gerenuks show that the causative mycoplasma has broader specificity. Diagnosis was hampered by the fastidiousness of the causative mycoplasma but molecular-based tests like PCR have greatly improved detection. Rapid latex agglutination tests that can be performed at the penside are also available for antibody detection. Clinically affected animals respond to a range of antibiotics although it is unlikely that this results in complete elimination of the mycoplasma. Vaccines consisting of saponized organisms have been shown to be protective but the quality and efficacy may be variable.

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BACKGROUND AND PURPOSEThe level of cell surface expression of the meningococcal vaccine antigen, Factor H binding protein (FHbp) varies between and within strains and this limits the breadth of strains that can be targeted by FHbp-based vaccines. The molecular pathway controlling expression of FHbp at the cell surface, including its lipidation, sorting to the outer membrane and export, and the potential regulation of this pathway have not been investigated until now. This knowledge will aid our evaluation of FHbp vaccines. EXPERIMENTAL APPROACHA meningococcal transposon library was screened by whole cell immuno-dot blotting using an anti-FHbp antibody to identify a mutant with reduced binding and the disrupted gene was determined. KEY RESULTSIn a mutant with markedly reduced binding, the transposon was located in the lnt gene which encodes apolipoprotein N-acyl transferase, Lnt, responsible for the addition of the third fatty acid to apolipoproteins prior to their sorting to the outer membrane. We provide data indicating that in the Lnt mutant, FHbp is diacylated and its expression within the cell is reduced 10 fold, partly due to inhibition of transcription. Furthermore the Lnt mutant showed 64 fold and 16 fold increase in susceptibility to rifampicin and ciprofloxacin respectively. CONCLUSION AND IMPLICATIONSWe speculate that the inefficient sorting of diacylated FHbp in the meningococcus results in its accumulation in the periplasm inducing an envelope stress response to down-regulate its expression. We propose Lnt as a potential novel drug target for combination therapy with antibiotics. LINKED ARTICLESThis article is part of a themed section on Drug Metabolism and Antibiotic Resistance in Micro-organisms. To view the other articles in this section visit