Production and characterization of a new detergent-stable keratinase expressed by Pedobacter sp. 3.14.7, a novel Antarctic psychrotolerant keratin-degrading bacterium

BACKGROUND

Antarctica is one of the harshest environments in the world. Despite this fact, it has been colonized by microorganisms, which had to develop different adaptations in order to survive. By studying their enzymes, we can harness these adaptations in order to use them in various industrial processes. Keratinases (E.C. 3.4.99.11) are characterized by their robustness in withstanding extreme conditions and, along with other enzymes, are commonly added to laundry detergents, which makes their study of industrial interest.

RESULTS

In this work, a novel keratinase producer, Pedobacter sp. 3.14.7 (MF 347939.1), isolated from Antarctic birds' nests, was identified. This psychrotolerant isolate displays a typical psychrotolerant growth pattern, with an optimal temperature of 20 °C (μmax=0.23 h^-1). After 238 h, maximum proteolytic (22.00 ± 1.17 U ml^-1) and keratinolytic (33.04 ± 1.09 U ml^-1) activities were achieved with a feather sample conversion of approximately 85%. The keratinase present in crude extract was characterized as a metalloprotease with a molecular weight of 25 kDa, stable in a wide range of pH, with an optimum pH of 7.5. Optimum temperature was 55 °C. Wash performance at 20 °C using this crude extract could remove completely blood stain from cotton cloth.

CONCLUSION

We report a new keratinolytic bacteria from maritime Antarctica. Among its biochemical characteristics, its stability in the presence of different detergents and bleaching agents and its wash performance showed promising results regarding its potential use as a laundry detergent additive.

Evaluation of recorded video-observed therapy for anti-tuberculosis treatment

BACKGROUND: Asynchronous video directly observed therapy (VDOT) may reduce tuberculosis (TB) program costs and the burden on patients. We compared VDOT performance across three cities in the United States, each of which have TB incidence rates above the national average.METHODS: Patients aged ≥18 years who are currently receiving directly observed anti-TB treatment were invited to use VDOT for monitoring treatment. Pre- and post-treatment interviews and medical records were used to assess site differences in treatment adherence and patient characteristics and perceptions.RESULTS: Participants were enrolled in New York City, NY (n = 48), San Diego, CA (n = 52) and San Francisco, CA, USA (n = 49). Overall, the mean age was 41 years (range 18-87); 59% were male; most were Asian (45%) or Hispanic/Latino (30%); and 77% were foreign-born. The median fraction of expected doses observed (FEDO) was 88% (IQR 76-96). At follow-up, 97% thought VDOT was "very or somewhat easy to use" and 95% would recommend VDOT to other TB patients. Age, race/ethnicity, annual income, and country of birth differed by city (P < 0.05), but FEDO and VDOT perceptions did not.CONCLUSIONS: TB programs in three large US cities observed a high FEDO using VDOT while minimizing staff time and travel. Similar findings across sites support VDOT adoption by other large, urban TB programs.

Tracking Antimicrobial Resistance Determinants in Diarrheal Pathogens: A Cross-Institutional Pilot Study

Infectious diarrhea affects over four billion individuals annually and causes over a million deaths each year. Though not typically prescribed for treatment of uncomplicated diarrheal disease, antimicrobials serve as a critical part of the armamentarium used to treat severe or persistent cases. Due to widespread over- and misuse of antimicrobials, there has been an alarming increase in global resistance, for which a standardized methodology for geographic surveillance would be highly beneficial. To demonstrate that a standardized methodology could be used to provide molecular surveillance of antimicrobial resistance (AMR) genes, we initiated a pilot study to test 130 diarrheal pathogens (Campylobacter spp., Escherichia coli, Salmonella, and Shigella spp.) from the USA, Peru, Egypt, Cambodia, and Kenya for the presence/absence of over 200 AMR determinants. We detected a total of 55 different determinants conferring resistance to ten different categories of antimicrobials: genes detected in ≥ 25 samples included bla_TEM, tet(A), tet(B), mac(A), mac(B), aadA1/A2, strA, strB, sul1, sul2, qacEΔ1, cmr, and dfrA1. The number of determinants per strain ranged from none (several Campylobacter spp. strains) to sixteen, with isolates from Egypt harboring a wider variety and greater number of genes per isolate than other sites. Two samples harbored carbapenemase genes, bla_OXA-48 or bla_NDM. Genes conferring resistance to azithromycin (ere(A), mph(A)/mph(K), erm(B)), a first-line therapeutic for severe diarrhea, were detected in over 10% of all Enterobacteriaceae tested: these included >25% of the Enterobacteriaceae from Egypt and Kenya. Forty-six percent of the Egyptian Enterobacteriaceae harbored genes encoding CTX-M-1 or CTX-M-9 families of extended-spectrum β-lactamases. Overall, the data provide cross-comparable resistome information to establish regional trends in support of international surveillance activities and potentially guide geospatially informed medical care.

First Report of New Delhi Metallo-β-Lactamase Carbapenemase-Producing Acinetobacter baumannii in Peru

Here we report the first incidence of New Delhi metallo-β-lactamase (NDM-1)-producing Acinetobacter baumannii in Peru, identified via a strain-based nosocomial surveillance project carried out in Lima and Iquitos. The bla _NDM-1 gene was detected by multiplex polymerase chain reaction (PCR) and confirmed by loci sequencing. Acinetobacter baumannii is a nearly ubiquitous and promiscuous nosocomial pathogen, and the acquisition of bla _NDM-1 by A. baumannii may facilitate an increase in the prevalence of this important resistance marker in other nosocomial pathogens.

Molecular mechanism of SHP2 activation by PD-1 stimulation

In cancer, the programmed death-1 (PD-1) pathway suppresses T cell stimulation and mediates immune escape. Upon stimulation, PD-1 becomes phosphorylated at its immune receptor tyrosine-based inhibitory motif (ITIM) and immune receptor tyrosine-based switch motif (ITSM), which then bind the Src homology 2 (SH2) domains of SH2-containing phosphatase 2 (SHP2), initiating T cell inactivation. The SHP2-PD-1 complex structure and the exact functions of the two SH2 domains and phosphorylated motifs remain unknown. Here, we explain the structural basis and provide functional evidence for the mechanism of PD-1-mediated SHP2 activation. We demonstrate that full activation is obtained only upon phosphorylation of both ITIM and ITSM: ITSM binds C-SH2 with strong affinity, recruiting SHP2 to PD-1, while ITIM binds N-SH2, displacing it from the catalytic pocket and activating SHP2. This binding event requires the formation of a new inter-domain interface, offering opportunities for the development of novel immunotherapeutic approaches.

A comparison of methods for DNA preparation prior to microarray analysis

Microarrays are a valuable tool for analysis of both bacterial and eukaryotic nucleic acids. As many of these applications use non-specific amplification to increase sample concentration prior to analysis, the methods used to fragment and label large amplicons are important to achieve the desired analytical selectivity and specificity. Here, we used eight sequenced ESKAPE pathogens to determine the effect of two methods of whole genome amplicon fragmentation and three methods of subsequent labeling on microarray performance; nick translation was also assessed. End labeling of both initial DNase I-treated and sonication-fragmented amplicons failed to provide detectable material for a significant number of sequence-confirmed genes. However, processing of amplicons by nick translation, or by sequential fragmentation and labeling by Universal Labeling System or Klenow fragment/random primer provided good sensitivity and selectivity, with marginally better results obtained by Klenow fragment labeling. Nick-translation provided 91-100% sensitivity and 100% specificity in the tested strains, requiring half as many manipulations and less than 4h to process samples for hybridization; full sample processing from whole genome amplification to final data analysis could be performed in less than 10h. The method of template denaturation before amplification did affect detection sensitivity/selectivity of nick-labeled amplicons, however.

Extended-spectrum β-lactamase-producing Enterobacteriaceae in cell phones of health care workers from Peruvian pediatric and neonatal intensive care units

BACKGROUND

Health care workers (HCWs) use their mobile phones during working hours or medical care. There is evidence that the instruments are colonized with pathogenic microorganisms. Here, we describe levels of Enterobacteriaceae contamination (EC) in cell phones and the risk factors associated with EC in Peruvian intensive care units (ICUs).

METHODS

This was a 5-month cohort study among 114 HCWs of 3 pediatric and 2 neonatology ICUs from 3 Peruvian hospitals. A baseline survey collected data on risk factors associated with EC. Swabs were collected from HCWs' phones every other week.

RESULTS

Three-quarters of HCWs never decontaminated their phones, and 47% reported using the phones in the ICU >5 times while working. EC was frequent across samplings and sites and was substantially higher in subjects with longer follow-up. Potential risk factors identified did not have strong associations with positive samples (relative risk, 0.7-1.5), regardless of significance. Half of the phones were colonized with an Enterobacteriaceae at least once during the 4 samplings attained on average during the study period. Half of the isolates were multidrug resistant (MDR), and 33% were extended-spectrum β-lactamase producers.

CONCLUSIONS

EC on HCWs' phones was frequent and apparently randomly distributed through the hospitals without clear clustering or strongly associated risk factors for having a positive sample. Based on the level of EC, phones may be considered as potential bacterial reservoirs of MDR and ESBL bacteria.

Feasibility of tuberculosis treatment monitoring by video directly observed therapy: a binational pilot study

BACKGROUND

Although directly observed therapy (DOT) is recommended worldwide for monitoring anti-tuberculosis treatment, transportation and personnel requirements limit its use.

OBJECTIVE

To evaluate the feasibility and acceptability of 'video DOT' (VDOT), which allows patients to record and transmit medication ingestion via videos watched remotely by health care providers to document adherence.

METHODS

We conducted a single-arm trial among tuberculosis (TB) patients in San Diego, California, USA, (n = 43) and Tijuana, Mexico (n = 9) to represent high- and low-resource settings. Pre-/post-treatment interviews assessed participant characteristics and experiences. Adherence was defined as the proportion of observed doses to expected doses.

RESULTS

The mean age was 37 years (range 18-86), 50% were male, and 88% were non-Caucasian. The mean duration of VDOT use was 5.5 months (range 1-11). Adherence was similar in San Diego (93%) and Tijuana (96%). Compared to time on in-person DOT, 92% preferred VDOT, 81% thought VDOT was more confidential, 89% never/rarely had problems recording videos, and 100% would recommend VDOT to others. Seven (13%) participants were returned to in-person DOT and six (12%) additional participants had their phones lost, broken or stolen.

CONCLUSIONS

VDOT was feasible and acceptable, with high adherence in both high- and low-resource settings. Efficacy and cost-effectiveness studies are needed.

A novel human glycoprotein ACA is an upstream regulator of human hematopoiesis

A central issue in stem cell biology is a better understanding of the molecular mechanisms that regulate self-renewal of human hematopoietic stem cells (HSCs). Control of the specific function of HSCs like self-renewal and differentiation might be regulated by a common set of critical genes. However, the regulation among these genes is yet to be elucidated. Here, we show that activation by a novel human GPI-linked glycoprotein ACA at the surface of human peripheral blood progenitor cells induces via PI3K/Akt/mTor/PTEN upregulation of WNT, Notch1, Bmi-1 and HoxB4 genes thus, promoting self-renewal and generation of primitive HSCs. ACA-generated self-renewing cells retained their lympho-myeloid repopulating potential in NOD/SCID mouse xeno-transplantation model with long term functional capacity. We conclude that ACA is an essential regulator of the genes involved in maintaining hematopoiesis and its use in clinical praxis could overcome many of the barriers present so far in transplantation medicine.

Afro-American migrant farmworkers: a culture in isolation

Increasing rates of HIV infection have been found in migrant farmworkers in the USA over the past decade. By virtue of lifestyle, language and culture, these workers are not exposed to the typical media HIV prevention messages. To determine their level of knowledge about this disease for use in prevention messages targeted specifically to this population, five gender specific focus groups were conducted among Haitian, Jamaican and African-American migrant farmworkers in upstate New York. The focus groups revealed that the health belief system of these Afro-American migrant workers primarily reflects that of their indigenous culture. This impacts their interpretation and utilization of risk aversive behaviours. The data also suggest that the culture of migrancy itself affects the extent of risky behaviours practised, but further studies are needed to examine this phenomenon.

Real-life-type problem-solving in Asperger's syndrome

This study compared adolescents with Asperger's syndrome with typically developing adolescents on a novel problem-solving task that presented videotaped scenarios in real-life-type social contexts. The Asperger's group was impaired in several aspects of problem-solving, including recounting the pertinent facts, generating possible high-quality problem solutions, and selecting optimal and preferred solutions. This group's solutions differed most from those of the typically developing group in social appropriateness. The contributions of social experience, social understanding, and executive skills to performance on the novel problem-solving task are discussed.

A case-control family history study of autism

Family history data on 99 autistic and 36 Down's syndrome probands are reported. They confirmed a raised familial loading for both autism and more broadly defined pervasive developmental disorders in siblings (2.9% and 2.9%, respectively, vs 0% in the Down's group) and also evidence for the familial aggregation of a lesser variant of autism, comprising more subtle communication/social impairments or stereotypic behaviours, but not mental retardation alone. Between 12.4 and 20.4% of the autism siblings and 1.6% and 3.2% of the Down's siblings exhibited this lesser variant, depending on the stringency of its definition. Amongst autistic probands with speech, various features of their disorder (increased number of autistic symptoms; reduced verbal and performance ability) as well as a history of obstetric complications, indexed an elevation in familial loading. No such association was seen in the probands without speech, even though familial loading for the lesser variant in this subgroup, was significantly higher than in the Down's controls. The findings suggest that the autism phenotype extends beyond autism as traditionally diagnosed; that aetiology involves several genes; that autism is genetically heterogeneous; and that obstetric abnormalities in autistic subjects may derive from abnormality in the foetus.

Primary structure of Trypanosoma cruzi small-subunit ribosomal RNA coding region: comparison with other trypanosomatids

A Trypanosoma cruzi small subunit ribosomal RNA gene was sequenced from genomic recombinant plasmid clones. The assigned coding region was 2319 bp, the longest SSU rRNA gene described to date. On the basis of comparisons with published sequences from Crithidia fasciculata, Trypanosoma brucei, and Leishmania donovani, we conclude that the extra nucleotides in the T. cruzi gene occur in highly variable regions of rRNA genes. A phylogenetic analysis was performed with the SSU rRNA sequences from these four trypanosomatids and from Euglena gracilis as an outgroup. The Leishmania and Crithidia sequences were remarkably similar to each other (not separable statistically). Given the standard errors associated with the branching order of the two Trypanosoma species and the Leishmania-Crithidia branch, the actual topology cannot be unequivocally determined using only the ribosomal sequences analyzed here.

Recognition and expression of emotional cues by autistic and normal adults

High-functioning autistic adults were compared with normal adults using a battery of tests devised to assess the recognition and expression of emotional cues in both facial and vocal modalities. The autistic subjects were relatively impaired in both the appreciation and production of emotional expressions. Although no one test provided a clear-cut separation of the groups at the individual level, composite scores did separate the groups quite well. It is suggested that this battery of tasks may have some value in family genetic studies of autism that need to identify subclinical deficits that might be aetiologically linked with autism.

Autism diagnostic interview: a standardized investigator-based instrument

The development of a new standardized investigator-based interview for use in the differential diagnosis of pervasive developmental disorders is described, together with a diagnostic algorithm (using ICD-10 criteria) based on its use. Good interrater reliability for algorithm items was shown between four raters, two in Canada and two in the UK, who rated 32 videotaped interviews. The items also significantly discriminated between 16 autistic and 16 nonautistic mentally handicapped subjects. The algorithm based on ICD-10 identified all 16 autistic individuals and none of the 16 nonautistic subjects.