Extensive variation at MHC DRB in the New Zealand sea lion (Phocarctos hookeri) provides evidence for balancing selection.

Marine mammals are often reported to possess reduced variation of major histocompatibility complex (MHC) genes compared with their terrestrial counterparts. We evaluated diversity at two MHC class II B genes, DQB and DRB, in the New Zealand sea lion (Phocarctos hookeri, NZSL) a species that has suffered high mortality owing to bacterial epizootics, using Sanger sequencing and haplotype reconstruction, together with next-generation sequencing. Despite this species' prolonged history of small population size and highly restricted distribution, we demonstrate extensive diversity at MHC DRB with 26 alleles, whereas MHC DQB is dimorphic. We identify four DRB codons, predicted to be involved in antigen binding, that are evolving under adaptive evolution. Our data suggest diversity at DRB may be maintained by balancing selection, consistent with the role of this locus as an antigen-binding region and the species' recent history of mass mortality during a series of bacterial epizootics. Phylogenetic analyses of DQB and DRB sequences from pinnipeds and other carnivores revealed significant allelic diversity, but little phylogenetic depth or structure among pinniped alleles; thus, we could neither confirm nor refute the possibility of trans-species polymorphism in this group. The phylogenetic pattern observed however, suggests some significant evolutionary constraint on these loci in the recent past, with the pattern consistent with that expected following an epizootic event. These data may help further elucidate some of the genetic factors underlying the unusually high susceptibility to bacterial infection of the threatened NZSL, and help us to better understand the extent and pattern of MHC diversity in pinnipeds.

Comparison of single-incision laparoscopic high anterior resection with standard laparoscopic high anterior resection.

AIM: Single-incision laparoscopic surgery (SILS) is gaining momentum. The aim of the present study was to compare the outcome of SILS for high anterior resection with that of standard laparoscopic resection (StdLS). METHOD: Patients undergoing laparoscopic high anterior resection were prospectively entered into an institutional approved database. Patients treated with SILS were compared with those undergoing StdLS. RESULTS: Between April 2000 and April 2009, 327 (143 cancer) consecutive unselected patients underwent StdLS; there were three (1%) conversions and 12 (3.6%) covering ileostomies. After April 2009, 55 (29 cancer) consecutive, unselected patients underwent SILS; there were two conversions to a three-port technique (3.6%), no conversions to open resection and two (3.6%) covering ileostomies. There were no significant differences in age, sex, body mass index, hospital of operation or American Society of Anesthesiology (ASA) grade between the two groups. The operating time for SILS was significantly shorter (113 ± 44 min for StdLS vs 79 ± 37 min for SILS; P < 0.0001). SILS patients tolerated a normal diet earlier [10 (2-24) h for SILS vs 18 (2-96) h for StdLS] and were discharged faster [1 (1-8) days for SILS vs 3 (1-24) days for StdLS]. There were no significant differences in return to theatre, readmissions or 30-day mortality. CONCLUSION: SILS for high anterior resection is feasible, safe and quicker to perform than standard three-port laparoscopic colectomy. It seems to be associated with a faster recovery and earlier discharge.

Single incision laparoscopic adjustable gastric band: technique, feasibility, safety and learning curve.

INTRODUCTION: Single incision laparoscopic surgery (SILS) is established in many procedures but not in bariatric surgery. One explanation may be that SILS is technically demanding in morbidly obese patients. This report describes our technique and experience with single incision laparoscopic adjustable gastric banding (SILAGB). METHODS: Prospective data collection was performed on consecutive obese patients who underwent SILAGB between November 2009 and February 2011. A single 3 cm transverse incision in the right upper quadrant was used for a Covidien SILS™ multichannel access port. The technique is described with a standard pars flaccida approach and the 'tips and tricks' needed for a wide range of candidates using standard laparoscopic equipment. RESULTS: A total of 29 patients (27 female) with a median body mass index of 41 kg/m(2) (range: 35-52 kg/m(2)) and median age of 44 years (range: 22-57 years) underwent SILAGB. There were no 'conversions' to a standard laparoscopic technique. Two cases required the addition of one single 5 mm port. The only complications were two postoperative wound infections (one with a port site infection requiring replacement of the port) and one faulty band requiring replacement. There were therefore two returns to theatre and no 30-day deaths. All patients were discharged on the first postoperative day. In this series, operative times reduced significantly to be comparable with the conventional laparoscopic approach. CONCLUSIONS: SILAGB is safe and feasible in the morbidly obese. Proficiency in this technique using conventional laparoscopic equipment can be achieved with a short learning curve.

Gastrointestinal tract colonization with vancomycin-resistant Enterococcus faecium in an animal model.

Vancomycin-resistant enterococci have become important nosocomial pathogens in many institutions. The gastrointestinal tract of susceptible hosts serves as the likely reservoir from which the organism is disseminated. To study factors promoting colonization and the efficacy of decontamination therapy with antimicrobial agents, a model of gastrointestinal colonization with vancomycin-resistant Enterococcus faecium was developed in CF1 mice. At baseline, all animals were colonized with non-vancomycin-resistant enterococci (5.0 log10 CFU/g), but vancomycin-resistant organisms were not detectable. Following gastric inoculation with 5 x 10(8) CFU of a clinical isolate of vancomycin-resistant E. faecium, the strain transiently colonized the gastrointestinal tract of 100% of mice but was undetectable by Day 14 (< or = 2.7 log10 mean CFU/g). In animals who received 5 mg of streptomycin per ml or 250 micrograms of vancomycin per ml in drinking water, colonization with the organism occurred at significantly higher bacterial counts than in controls at 7 days following inoculation (9.4 for vancomycin, 9.2 for streptomycin, and 5.1 log10 mean CFU/g for controls; P < 0.05). Fecal concentrations of vancomycin-resistant E. faecium persisted at high counts through Day 22 in mice receiving these antibiotics, but low counts were also still detected in 3 of 10 control animals. In mice with previously established vancomycin-resistant E. faecium colonization, oral administration of ramoplanin, a lipoglycodepsipeptide to which the strain was susceptible, suppressed growth of all enterococci in feces, including the vancomycin-resistant strain after 7 days of therapy (< or = 3.1 and < or = 3.3 log10 mean CFU/g for vancomycin and streptomycin groups, respectively). All mice had a recurrence of colonization with vancomycin-resistant E. faecium after the ramoplanin was discontinued. In summary, this animal model demonstrates the importance of antibiotics in predisposing to gastrointestinal colonization with vancomycin-resistant Enterococcus spp. Although treatment with ramoplanin temporarily suppressed the organism, recurrence of colonization due to relapse or reinfection occurred.

Antibiotic treatment of experimental endocarditis due to vancomycin- and ampicillin-resistant Enterococcus faecium.

We compared ciprofloxacin, rifampin, and gentamicin treatments, alone and in combination, for 5 days in the therapy of experimental aortic valve endocarditis in rats caused by a clinical isolate of vancomycin-resistant Enterococcus faecium. The MICs and MBCs of vancomycin, ciprofloxacin, rifampin, and gentamicin were 250 and > 1,000, 3.1 and 6.3, 0.098 and 1.6, and 12.5 and > 50 micrograms/ml, respectively. Infected rats were sacrificed after completing 5 days of therapy. Additional rats within each treatment group were followed for 5 days beyond the last dose of antibiotic therapy. Although survivals in the different groups were not significantly different after 5 days of therapy, survival was significantly better 5 days beyond the last dose of antibiotic therapy in rats treated with rifampin-containing regimens. The combination of ciprofloxacin and gentamicin was bactericidal in vitro and in vegetations from rats with enterococcal endocarditis. Rifampin alone was similarly bactericidal in vivo, but it was not significantly better than rifampin in combination with other antibiotics. Subpopulations resistant to rifampin, but not ciprofloxacin, were detected in the inoculum and in most vegetations during therapy. However, the combination of ciprofloxacin plus both gentamicin and rifampin reduced both the rifampin-susceptible and -resistant population in vegetations of 9 of 10 animals below the level of detection after 5 days of therapy. Nevertheless, a residual enterococcal population apparently remained in numbers of < 2 log10 CFU/g after 5 days of therapy, which resulted in relapse. Perhaps a longer course of therapy would have eliminated this residual population and improved efficacy.