Pseudomonas pseudoalcaligenes CECT5344, a cyanide-degrading bacterium with by-product (polyhydroxyalkanoates) formation capacity.

BACKGROUND: Cyanide is one of the most toxic chemicals produced by anthropogenic activities like mining and jewelry industries, which generate wastewater residues with high concentrations of this compound. Pseudomonas pseudoalcaligenes CECT5344 is a model microorganism to be used in detoxification of industrial wastewaters containing not only free cyanide (CN(-)) but also cyano-derivatives, such as cyanate, nitriles and metal-cyanide complexes. Previous in silico analyses suggested the existence of genes putatively involved in metabolism of short chain length (scl-) and medium chain length (mcl-) polyhydroxyalkanoates (PHAs) located in three different clusters in the genome of this bacterium. PHAs are polyesters considered as an alternative of petroleum-based plastics. Strategies to optimize the bioremediation process in terms of reducing the cost of the production medium are required. RESULTS: In this work, a biological treatment of the jewelry industry cyanide-rich wastewater coupled to PHAs production as by-product has been considered. The functionality of the pha genes from P. pseudoalcaligenes CECT5344 has been demonstrated. Mutant strains defective in each proposed PHA synthases coding genes (Mpha(-), deleted in putative mcl-PHA synthases; Spha(-), deleted in the putative scl-PHA synthase) were generated. The accumulation and monomer composition of scl- or mcl-PHAs in wild type and mutant strains were confirmed by gas chromatography-mass spectrometry (GC-MS). The production of PHAs as by-product while degrading cyanide from the jewelry industry wastewater was analyzed in batch reactor in each strain. The wild type and the mutant strains grew at similar rates when using octanoate as the carbon source and cyanide as the sole nitrogen source. When cyanide was depleted from the medium, both scl-PHAs and mcl-PHAs were detected in the wild-type strain, whereas scl-PHAs or mcl-PHAs were accumulated in Mpha(-) and Spha(-), respectively. The scl-PHAs were identified as homopolymers of 3-hydroxybutyrate and the mcl-PHAs were composed of 3-hydroxyoctanoate and 3-hydroxyhexanoate monomers. CONCLUSIONS: These results demonstrated, as proof of concept, that talented strains such as P. pseudoalcaligenes might be applied in bioremediation of industrial residues containing cyanide, while concomitantly generate by-products like polyhydroxyalkanoates. A customized optimization of the target bioremediation process is required to gain benefits of this type of approaches.

Methicillin-resistant Staphylococcus aureus infection after lung transplantation: 5-year review of clinical and molecular epidemiology.

BACKGROUND: Data on the epidemiology of MRSA infection in lung transplantation is limited. METHODS: We performed a 5-year retrospective study to assess the incidence and microbiologic and clinical characteristics of methicillin-resistant Staphylococcus aureus (MRSA) infection in a cohort of 163 lung transplant recipients. RESULTS: Seventeen patients with MRSA colonization and/or infection were identified, for a calculated incidence rate of 76.1 cases per 1,000 transplanted-years. Pulsed-field gel electrophoresis identified 3 different distinct MRSA profiles, all of them consistent with hospital-associated MRSA infection. CONCLUSION: Despite negative polymerase chain reaction (PCR) for the virulence factor Panton-Valentine leukocidin, MRSA infections resulted in significant disease and morbidity.

A randomized, double-blind, placebo-controlled trial to evaluate the prime-boost strategy for pneumococcal vaccination in adult liver transplant recipients.

BACKGROUND: The 23-valent pneumococcal polysaccharide vaccine (PPV23) is recommended for disease prevention in solid-organ transplant recipients, but it may have suboptimal immunogenicity. It may be possible to enhance immunogenicity by priming the recipient with the 7-valent pneumococcal conjugate vaccine (PCV7), followed by boosting with PPV23. METHODS: We randomized adult liver transplant recipients to receive either (1) PCV7 followed by a PPV23 booster 8 weeks later (the "primed" group) or (2) placebo followed by a standard single dose of PPV23 (the "unprimed" group). Quantitative and functional antibody titers for 7 serotypes contained in both vaccines were measured at baseline, 8 weeks after enrollment, and 16 weeks after enrollment. Of 130 randomized patients, 113 completed the study. RESULTS: At week 16, response to at least 1 serotype was seen in 48 (85.7%) of 56 and 52 (91.2%) of 57 patients for the primed and unprimed groups, respectively (P=not significant). The mean number of serotypes to have responded (+/-SD) was 307+/-2.3 and 4.4+/-2.2 for the primed and unprimed groups, respectively (P=not significant). Functional antibody titers, which were measured with use of the opsonophagocytic assay, were also similar in both groups. CONCLUSIONS: The immunogenicity of pneumococcal vaccination was not enhanced by the prime-boost strategy, compared with vaccination with PPV23 alone. Administration of a single dose of PPV23 should continue to be the standard of care for adult liver transplant recipients. CLINICAL TRIALS REGISTRATION: NCT00152802 (http://www.clinicaltrials.gov).

Incidence and clinical characteristics of herpes zoster after lung transplantation.

BACKGROUND: Solid-organ transplant recipients are at high risk for the development of herpes zoster. Epidemiologic data in lung transplant recipients are lacking. We determined the incidence and clinical characteristics of herpes zoster, and the risk factors for developing herpes zoster, after lung transplantation. METHODS: We retrospectively reviewed all adult (>18 years old) lung transplants performed at our institution between January 2001 and December 2005. Clinical characteristics of herpes zoster and potential risk factors associated with herpes zoster were assessed. RESULTS: Two hundred thirty-nine lung transplant recipients were included in the analysis. Median time of follow-up was 722 days (range 18 to 1,943 days). Thirty-five episodes of herpes zoster occurred in 29 patients, with a calculated incidence of 55.1 cases per 1,000 person-years of follow-up. The cumulative probability of herpes zoster was 5.8% at 1 year, 18.1% at 3 years and 20.2% at 5 years post-transplant. Only 2 of the 35 (5.7%) patients had disseminated cutaneous infection and none had visceral involvement. Recurrence of herpes zoster was seen in 13.8% of patients. Post-herpetic neuralgia was detected in 20% of cases. Anti-viral prophylaxis, primarily for cytomegalovirus (CMV), was protective against herpes zoster. No significant epidemiologic risk factors associated with herpes zoster could be identified. CONCLUSIONS: Herpes zoster is a common complication after lung transplantation with a peak incidence at between 1 and 4 years post-transplant. Preventive strategies would be beneficial for this population.

A randomized, double-blind trial of pneumococcal vaccination in adult allogeneic stem cell transplant donors and recipients.

BACKGROUND: Adult allogeneic hematopoietic stem cell transplant (HSCT) recipients are at high risk of invasive pneumococcal disease but have suboptimal responses to the recommended pneumococcal polysaccharide vaccine (PPV23). Pneumococcal conjugate vaccine (PCV7) may improve immunogenicity in this population, and a donor vaccination strategy may benefit patients undergoing HSCT. METHODS: Sixty-four pairs of donors and recipients scheduled to undergo HSCT were randomized to receive either PPV23 or PCV7. Vaccinations were administered to donors before transplantation and to recipients at 6 months after transplantation. Serotype-specific antipneumococcal titers were measured in donors at the time of harvest and in recipients before transplantation and 6 and 12 months after transplantation. RESULTS: Overall, immunogenicity was poor with both strategies. However, at 6 months, response to at least 1 serotype was seen in 0 (0%) of 19 and 8 (38.6%) of 21 evaluable recipients whose donors had received PPV23 and PCV7, respectively (P=.003). At 12 months, response was seen in 10 (55.6%) of 18 and 20 (90.9%) of 22 HSCT recipients who had received PPV23 and PCV7, respectively (P=.02). Multivariate logistic regression revealed that, at 12 months after transplantation, the type of vaccine given was the only significant factor affecting response, with an odds ratio of 8.85 (95% confidence interval, 1.62-47.6; P=.012) favoring PCV7. CONCLUSION: A donor and recipient paired vaccination strategy with PCV7 demonstrated safety and greater immunogenicity than did a similar strategy with PPV23.