- Volume 62, Issue 1, 2013

Bovine trichomoniasis is a sexually transmitted protozoan disease with a worldwide distribution. It has been endemic in the USA for more than 80 years. Mississippi and all the states west of the Mississippi River, except Iowa and Minnesota, have rules/regulations to reduce the spread of the disease. The core of these regulations consists of testing bulls and prohibiting importation of non-Tritrichomonas foetus-free bulls. Factors such as sampling methods and intervals, shipping medium and temperature, and testing techniques are reviewed for their effect on diagnostic accuracy. Finally, a comprehensive approach for controlling and eventually eradicating the disease is presented.

Listeria monocytogenes is a food-borne pathogen responsible for the disease listeriosis. The infectious process depends on survival in the high bile-salt conditions encountered throughout the gastrointestinal tract, including the gallbladder. However, it is not clear how bile-salt resistance mechanisms are induced, especially under physiologically relevant conditions. This study sought to determine how the L. monocytogenes strains EGDe (serovar 1/2a), F2365 (serovar 4a) and HCC23 (serovar 4b) respond to bile salts under anaerobic conditions. Changes in the expressed proteome were analysed using multidimensional protein identification technology coupled with electrospray ionization tandem mass spectrometry. In general, the response to bile salts among the strains tested involved significant alterations in the presence of cell-wall-associated proteins, DNA repair proteins, protein folding chaperones and oxidative stress-response proteins. Strain viability correlated with an initial osmotic stress response, yet continued survival for EGDe and F2365 involved different mechanisms. Specifically, proteins associated with biofilm formation in EGDe and transmembrane efflux pumps in F2365 were expressed, suggesting that variations exist in how virulent strains respond and adapt to high bile-salt environments. These results indicate that the bile-salt response varies among these serovars and that further research is needed to elucidate how the response to bile salts correlates with colonization potential in vivo.

A major barrier to using genome sequencing in medical microbiology is the ability to interpret the data. New schemes that provide information about the importance of sequence variation in both clinical and public health settings are required. Meticillin-resistant Staphylococcus aureus (MRSA) is an important nosocomial pathogen that is being observed with increasing frequency in community settings. Better tools are needed to improve our understanding of its transmissibility and micro-epidemiology in order to develop effective interventions. Using DNA microarray technology we identified a set of 20 binary targets whose presence or absence could be determined by PCR, producing a PCR binary typing scheme (PCR-BT). This was combined with multi-locus sequence type-based, sequence nucleotide polymorphism typing to form a hierarchical typing scheme. When applied to a set of epidemiologically unrelated isolates, a high degree of concordance was observed with PFGE (98.8 %). The scheme was able to detect the presence or absence of an outbreak strain in eight out of nine outbreak investigations, demonstrating epidemiological concordance. PCR-BT was better than PFGE at distinguishing between outbreak strains, particularly where epidemic MRSA-15 was involved. The method developed here is a rapid, digital typing scheme for S. aureus for use in both micro- and macro-epidemiological investigations that has the advantage of being suitable for use in routine diagnostic laboratories. The targets are defined and therefore the types can be defined by any platform capable of detecting the sequences used, including whole genome sequencing.

The objectives of this study were to assess the activity of oxytetracycline (OTC), danofloxacin and tulathromycin against Mycoplasma mycoides subsp. mycoides Small Colony, the causative agent of contagious bovine pleuropneumonia, in an in vitro dynamic concentration model and to determine the concentration and/or time dependence of such activity. Time–kill assays that simulated elimination of antimicrobials from the body were performed. Initial antimicrobial concentrations corresponded to various multiples of the MIC and cultures were diluted in a stepwise fashion with either drug-free or drug-containing artificial medium to mimic administration by single-release bolus or infusion, respectively. Where appropriate, data were fitted to sigmoidal E max models. OTC produced no change in mycoplasma titre from the initial inoculum size, regardless of the concentration or means of drug exposure. Both danofloxacin and tulathromycin resulted in a decrease in mycoplasma titre but neither was bactericidal (99.9 % kill) over 12 h. A greater antimycoplasmal effect, defined as the change in log10 (c.f.u. ml−1) over 12 h, was achieved when danofloxacin was administered as a single-release bolus, suggesting concentration-dependent activity, whereas the antimycoplasmal effect of tulathromycin was comparable following administration by single-release bolus or infusion, owing to its long half-life.

In Europe, fetal loss due to Parvovirus B19 (B19V) is under-reported and a poorly addressed occupational risk to pregnant women. This is exemplified internationally, where it was unmentioned in the last two European Centre for Disease Prevention and Control (ECDC) annual surveillance reports or its 2009 special report on infections in pregnancy. To assess this potential for underestimating B19V fetal loss in pregnancy, we undertook a systematic review of practice in Northern Ireland in the management and reporting of B19V infections over a 12-month period of heightened transmission, one of six observed in a span of 9 years. Pregnant and non-pregnant women presented with symptomatic infection in 24 and 93 % of confirmed B19V infections, respectively, with no difference in viral loads. There was underinvestigation of viral causes of fetal loss, with only 143/2739 (5 %) tested for B19V, and a failure to follow up most non-immune women tested following rash contact. Occupational exposure was recorded in 31/60 (51.6 %) of pregnancies audited following rash exposure, the majority teachers or day care workers. Against a background seroprevalence of 66.5 % immunity in women of child-bearing years, two patterns of infection were identified. Firstly, pregnant women investigated for a rash or exposure to slapped cheek syndrome, where an infection incidence of 18 % was observed, resulted in 42 confirmed infections, all proceeding to healthy term deliveries. Secondly, pregnant women with unsuspected infection had six cases of confirmed B19V fetal loss, including four of 22 (18 %) diagnosed at autopsy, of which three were non-hydropic. While many studies have reported B19V fetal loss in pregnancy, there are no robust public health surveillance figures to draw on. That all six confirmed fetal losses came from the small number of miscarriages/stillbirths investigated, 143 out of 2739, suggests inadequate follow-up of those pregnancies where B19V-related fetal loss may be most common, and supports the need for enhanced surveillance pilots to address this significant gap in public health knowledge.

The purpose of the present study was to analyse mutations in the gyrA and gyrB genes of Mycobacterium tuberculosis and define the possible correlation between these mutations and resistance to levofloxacin (LVX), moxifloxacin (MFX) and gatifloxacin (GAT), based on their MICs. One hundred and forty-two M. tuberculosis clinical isolates were collected from pulmonary tuberculosis patients in the Moscow region. All M. tuberculosis strains were tested for drug susceptibility to rifampicin and isoniazid using the BACTEC MGIT 960 System and to ofloxacin (OFX) using the absolute concentration method on solid Lowenstein–Jensen slants. All in all, 68 strains were selected at random (38 strains were resistant and 30 were susceptible to OFX) for further analysis using the TB-BIOCHIP-2 test system and DNA sequence analysis. The MICs of LVX, MFX and GAT for selected strains were determined using the BACTEC MGIT 960 System. Mutations in the gyrA gene were observed in 36 out of 38 (94.7 %) OFX-resistant M. tuberculosis strains. Asn538Asp and Asp500His substitutions in the gyrB gene only were found in two (5.3 %) strains. Twenty-nine out of 30 OFX-sensitive M. tuberculosis strains had no mutations in either gene. One (3.3 %) OFX-sensitive M. tuberculosis strain carried an Arg485His substitution in gyrB. The results of our investigation showed that there is no clear correlation between the type of mutation in the genes gyrA and gyrB, and the MIC levels of LVX, MFX and GAT for resistant strains. Mutations in gyrA and Asn538Asp, and Asp500His substitutions in gyrB were associated with cross-resistance of M. tuberculosis to fluoroquinolones. The substitution Arg485His in gyrB does not confer resistance to LVX, MFX and GAT in M. tuberculosis.

Aspergillosis is one of the most common causes of death in captive birds. Aspergillus fumigatus accounts for approximately 95 % of aspergillosis cases and Aspergillus flavus is the second most frequent organism associated with avian infections. In the present study, the fungi were grown from avian clinical samples (post-mortem lung material) and environmental samples (eggs, food and litter). Microsatellite markers were used to type seven clinical avian isolates and 22 environmental isolates of A. flavus. A. flavus was the only species (28 % prevalence) detected in the avian clinical isolates, whereas this species ranked third (19 %) after members of the genera Penicillium (39 %) and Cladosporium (21 %) in the environmental samples. Upon microsatellite analysis, five to eight distinct alleles were detected for each marker. The marker with the highest discriminatory power had eight alleles and a 0.852 D value. The combination of all six markers yielded a 0.991 D value with 25 distinct genotypes. One clinical avian isolate (lung biopsy) and one environmental isolate (egg) shared the same genotype. Microsatellite typing of A. flavus grown from avian and environmental samples displayed an excellent discriminatory power and 100 % reproducibility. This study showed a clustering of clinical and environmental isolates, which were clearly separated. Based upon these results, aspergillosis in birds may be induced by a great diversity of isolates.

There is a paucity of information about the factors associated with oral colonization with Candida species and the changes associated with antiretroviral (ARV) therapy. This study investigated the role of ARV therapy and other factors in a study population. Relevant clinical and laboratory information was obtained and oral rinse specimens were tested for yeast identification. The findings were compared with previous data from the same clinic before ARV therapy was available. Of 197 patients, 117 (59.4 %) were colonized. Candida albicans was the dominant species (71 %) and Candida dubliniensis was the most frequent non-albicans Candida. The colonized group had a higher rate of concurrent tuberculosis (TB) infection (77.4 % compared with 56 % in the non-colonized patients, P = 0.03) and a lower median CD4+ count (346.5 cells mm−3) compared with the non-colonized group (418 cells mm−3). Participants not on ARV therapy and those having oral prosthesis were all colonized (P = 0.003 and P = 0.022, respectively). The oral Candida count was negatively correlated with the CD4+ count in participants on ARV therapy (P = 0.006). Associated factors using logistic regression were dental caries (odds ratio = 1.30; 95 % confidence interval = 1.07–1.60] and diabetes mellitus (odds ratio = 5.52; 95 % confidence interval = 1.68–18.12). The colonization rate was higher (81.3 %) as well as the yeast count before ARV therapy was available, while the prevalence of C. dubliniensis was found to have increased from 6.3 to 11 %. Dental caries, diabetes mellitus, oral prostheses and TB infection were associated with oral colonization. The colonization rate, variety and yeast counts declined with ARV therapy.

We studied the systemic effects of the intranasal administration of Lactobacillus casei on the immuno-coagulative response in pneumoccocal infection in immunocompromised mice. Weaned mice consumed a protein-free diet (PFD) for 21 days and were therefore malnourished. Malnourished mice were fed a balanced conventional diet (BCD) for 7 days (BCD group) or a BCD for 7 days with nasal administration of viable L. casei on days 6 and 7 (BCD+LcN group). The malnourished control mice (MNC) received a PFD, whereas the well-nourished control mice (WNC) continually consumed a BCD. At the end of the treatment period, the mice were infected with Streptococcus pneumoniae. At different times after infection, we analysed the following parameters: global coagulation system, activation of coagulation, coagulation inhibitors, platelet count, leukocyte count and myeloperoxidase (MPO) activity, total proteins, albumin and acute phase proteins (APPs). The MNC group showed greater impairment in the coagulation tests and an increase in the positive APPs. These parameters were normalized by the L. casei treatment. However, the number of leukocytes, decreased by malnutrition, was improved only by the administration of L. casei. After infection, the BCD+LcN group showed similar results to those of the WNC group for most of the haemostatic parameters. The BCD+LcN group did not show significant variations in the prothrombin time or in the level of anticoagulant protein C, but showed higher levels of fibrinogen, platelets, albumin, leukocytes and MPO activity compared with the different experimental groups. The intranasal administration of L. casei was effective in modulating the pro-inflammatory aspects of coagulation without affecting coagulation itself.

Tetanus is a neuromuscular disease in which Clostridium tetani exotoxin (tetanospasmin) produces muscle spasms, incapacitating its host. To our knowledge, C. tetani bacteraemia has never been reported in the literature. The ideal management of this entity remains unresolved given that there is no literature to guide the therapy.