An Evaluation of Passive and Active Approaches to Improve Tuberculosis Notifications in Afghanistan.

BACKGROUND: In Afghanistan, improving TB case detection remains challenging. In 2014, only half of the estimated incident TB cases were notified, and notifications have decreased since peaking in 2007. Active case finding has been increasingly considered to improve TB case notifications. While access to health services has improved in Afghanistan, it remains poor and many people seeking health services won't receive proper care. METHODS: From October 2011 through December 2012 we conducted three separate case finding strategies in six provinces of Afghanistan and measured impact on TB case notification. Systematically screening cough among attendees at 47 health facilities, active household contact investigation of smear-positive index TB patients, and active screening at 15 camps for internally displaced people were conducted. We collected both intervention yield and official quarterly notification data. Additional TB notifications were calculated by comparing numbers of cases notified during the intervention with those notified before the intervention, then adjusting for secular trends in notification. RESULTS: We screened 2,022,127 people for TB symptoms during the intervention, tested 59,838 with smear microscopy and detected 5,046 people with smear-positive TB. Most cases (81.7%, 4,125) were identified in health facilities while nearly 20% were found through active case finding. A 56% increase in smear-positive TB notifications was observed between the baseline and intervention periods among the 47 health facilities, where cases detected by all three strategies were notified. DISCUSSION: While most people with TB are likely to be identified through health facility screening, there are many people who remain without a proper diagnosis if outreach is not attempted. This is especially true in places like Afghanistan where access to general services is poor. Targeted active case finding can improve the number of people who are detected and treated for TB and can push towards the targets of the Stop TB Global Plan and End TB Strategy.

Success of active tuberculosis case detection among high-risk groups in urban slums in Pakistan.

BACKGROUND: In Pakistan, patients with symptoms suggestive of tuberculosis (TB) seek care from a wide array of health care providers, many of whom do not notify cases to the National TB Programme (NTP). SETTING: We evaluated an active case detection intervention in five randomly selected districts in urban slums of Sindh Province, Pakistan. OBJECTIVE: To evaluate the increase in case notification of smear-positive TB by active case finding at community-based chest camps by engaging the private providers. DESIGN: A cross-sectional study of TB case detection associated with a project using integrated intervention and chest camps. RESULTS: From April 2011 to September 2012, the total number of clients seen in the camps was 165 280. Of all the attendees, 13 481 (12.7%) were examined by sputum smear microscopy. The proportion of smear-positive results was significantly higher among those from engaged private providers than among those referred from camps (OR 1.54, 95%CI 1.42-1.66). During the project, the total number of smear-positive TB notifications increased over the intervention period from 5158 to 8275. CONCLUSION: Active case detection by engaging private providers and chest camps can significantly increase the number of smear-positive TB case notifications.

Genetic modifications to temperate Enterococcus faecalis phage Ef11 that abolish the establishment of lysogeny and sensitivity to repressor, and increase host range and productivity of lytic infection.

Ef11 is a temperate bacteriophage originally isolated by induction from a lysogenic Enterococcus faecalis strain recovered from an infected root canal, and the Ef11 prophage is widely disseminated among strains of E. faecalis. Because E. faecalis has emerged as a significant opportunistic human pathogen, we were interested in examining the genes and regulatory sequences predicted to be critical in the establishment/maintenance of lysogeny by Ef11 as a first step in the construction of the genome of a virulent, highly lytic phage that could be used in treating serious E. faecalis infections. Passage of Ef11 in E. faecalis JH2-2 yielded a variant that produced large, extensively spreading plaques in lawns of indicator cells, and elevated phage titres in broth cultures. Genetic analysis of the cloned virus producing the large plaques revealed that the variant was a recombinant between Ef11 and a defective FL1C-like prophage located in the E. faecalis JH2-2 chromosome. The recombinant possessed five ORFs of the defective FL1C-like prophage in place of six ORFs of the Ef11 genome. Deletion of the putative lysogeny gene module (ORFs 31-36) and replacement of the putative cro promoter from the recombinant phage genome with a nisin-inducible promoter resulted in no loss of virus infectivity. The genetic construct incorporating all the aforementioned Ef11 genomic modifications resulted in the generation of a variant that was incapable of lysogeny and insensitive to repressor, rendering it virulent and highly lytic, with a notably extended host range.

Bacteriophages induced from lysogenic root canal isolates of Enterococcus faecalis.

INTRODUCTION: Bacterial viruses play crucial roles in the pathogenesis of many systemic diseases. They are known to inhabit the oral cavity, both as free virions and as prophages in lysogenic bacterial strains; however, there has been no report of bacteriophages in endodontic infections. In this study, we sought to detect, isolate, and describe temperate bacteriophages harbored by Enterococcus faecalis strains isolated from endodontic infections. METHODS: Ten E. faecalis strains were isolated from root canals of teeth undergoing retreatment following unsuccessful endodontic therapy. Mitomycin C was used to induce any prophages present in the bacterial isolates. The induced phages were purified and examined using electron microscopy. The DNA extracted from one of the phage isolates was subjected to restriction endonuclease digestion and agarose electrophoresis analysis. RESULTS: Lysogeny was demonstrated in 4 of the 10 E. faecalis strains. Three of the lysogenic strains yielded phages exhibiting a Siphoviridae morphology, with long, non-contractile tails 130 nm in length, and spherical/icosahedral heads 41 nm in diameter. The virus induced from the fourth lysogenic E. faecalis strain had a contractile tail characteristic of Myoviridae. Restriction endonuclease analysis of NsiI and NdeI DNA fragments from one of the Siphoviridae phage isolates (phage phiEf11) indicated a genome size of approximately 41 kbp. CONCLUSION: This is the first report of lysogenic bacteria and their inducible viruses in infected root canals.

Public health practice in schools of public health: is there a fit?

Public health practice has been a part of schools of public health for a long time and yet it is still an emerging field of scholarship. Practice faculty often are isolated in their schools and not part of the mainstream. This article explores the elements of culture that are necessary to support a practice focus in a school of public health.

Isolation of viruses from stools in stem cell transplant recipients: a prospective surveillance study.

We prospectively examined stool specimens for enteric viruses in 75 stem cell transplant recipients (autologous 48, allogeneic 27) to determine the frequency and significance of these infections. Only six patients (8%) had a positive isolate. Five of these were allograft recipients (18%) compared to one autograft recipient (2%) (P = 0.02). Unrelated donor BMT recipients were at the highest risk for a viral isolate (OR = 10.5). Adenovirus was the commonest isolate (four patients). One patient each had an echovirus, enterovirus and small round structured virus identified. No correlation was found between the severity of gastro-intestinal symptoms and detection of a viral pathogen. There was no correlation with GVHD or CMV status. The only risk factor identified for isolation of an enterovirus was allogeneic BMT from an unrelated donor. There was a negative correlation with PBSC grafts. All the patients infected with an enteric virus had concomitant infection with other pathogens, compared to only 18% of uninfected patients (P = 0.001). The non-relapse mortality of the infected patients was 50% and only 7% in the uninfected patients (P = 0.01, OR = 12.5), although the isolated virus was the direct cause of death in one patient only. This study indicates a low rate of enteric virus isolation in recipients of PBSC grafts, both autologous and allogeneic. However, unrelated donor BMT is associated with a higher risk of enteric virus infection and an adverse outcome. Bone Marrow Transplantation (2000) 25, 277-282.

Total and specific IgE (house dust mite and intestinal helminths) in asthmatics and controls from Gondar, Ethiopia.

BACKGROUND: The role, if any, of parasitosis in the development of asthma remains incompletely understood; both 'protective' and 'predictive' associations have been reported. We report a study which examined immunoglobulin (Ig) E responses to two common helminths in asthmatics living in Ethiopia. OBJECTIVE: To compare the frequencies of specific IgE antibodies to Ascaris and Necator species and to Der p 1 among 84 adult asthmatics and a referent group of nonasthmatics. METHODS: A case-control analysis. RESULTS: Total IgE levels were not different between the two groups. The presence of specific IgE to Der p 1 was strongly associated with asthma (P = 0.001). Raised levels of Ascaris-(P = 0.010) and Necator- (P = 0.001) specific IgE antibodies were more common among referents; there were no associations between specific IgE production to Der p 1 and either of the two parasites. CONCLUSION: These findings confirm the association between Der p 1 sensitization and asthma among urban, adult Ethiopians. While they also indicate a negative relationship with two indicators of helminth infestation it appears that this is not mediated through the immunological response to common aeroallergens.

Managing information technology in academic medical centers: a "multicultural" experience.

Based on a session at the 1997 conference on Information Resources and Academic Medicine sponsored by the Association of American Medical Colleges, this article illustrates how the beliefs and concerns of academic medicine's diverse professional cultures affect the management of information technology. Two scenarios--one dealing with the standardization of desktop PCs, the other with publication of syllabi on an institutional intranet--form the basis of this exercise. Four prototypical members of a hypothetical medical center community--the chairman of surgery, a senior basic scientist, the chief information officer of an affiliated hospital, and the chief administrative officer--offer their perspectives on each scenario. Their statements illustrate many of the challenges of planning, deploying, and maintaining effective information technology in the "multicultural" environment of academic medical centers.

High-volume cellular screening for anticancer agents with combinatorial chemical libraries: a new methodology.

A single-step cancer cell cytotoxic assay system for anticancer drug discovery has been developed which facilitates rapid screening of large combinatorial chemical libraries synthesized using the 'one-bead-one-compound' (OBOC) methodology. Each OBOC library bead incorporates two orthogonally cleavable linkers that release the bead-bound compound at a different pH. The assay utilizes high concentrations of tumor cells mixed directly with OBOC beads and plated in soft agarose containing tissue culture medium. One of the orthogonal linkers is cleaved at neutral pH in tissue culture releasing an aliquot of compound to diffuse at a relatively high local concentration into the soft agarose immediately surrounding the bead. Active compounds are identified visually from a clear ring of tumor cell lysis which forms within 48 h around just the rare bead releasing a cytotoxic compound. The bead releasing a cytotoxin is then plucked from the agar and the remaining compound still linked to the bead can be released for structural analysis, followed by compound resynthesis and confirmatory testing. This assay system has been successfully applied to identification of lead cytotoxic compounds from model peptidic and non-peptidic combinatorial chemical libraries. Use of this methodology may facilitate anticancer drug discovery.

Artificial neural networks can distinguish novice and expert strategies during complex problem solving.

OBJECTIVE: To determine whether expert problem-solving strategies can be identified within a large number of student performances of complex medical diagnostic simulations. METHODS: Self-organizing artificial neural networks were trained to categorize the performances of infectious disease subspecialists on six computer-based clinical diagnostic simulation that used the sequence of diagnostic tests requested as the input data. Six hundred seventy-six student solutions to these problems were presented to these trained neural networks to determine which, if any, of the student solutions represented those of the experts. RESULTS: For each simulation, the expert performances clustered around one dominant output neurode, indicating that there were common problem-specific features associated with the experts' problem-solving performances. When the performances of students who also made correct problem diagnoses were tested on these expert-trained neural networks, 17% were classified as representing expert strategies, indicating that expert performance was a somewhat rare and inconsistent occurrence among the students. CONCLUSIONS: The ability to identify a small number of expert-like strategies within a large body of student performances may provide an opportunity to study the dynamics of complex learning at both individual and population levels as well as the emergence of medical diagnostic expertise.

A study of public health nursing directors in state health departments.

Public health nurses make up the largest single category of public health manpower, but confusion over where and how public health nurses should function continues. The purposes of this study were to describe the current structure of public health nursing in state health departments in the United States, and to note whether this structure had changed over the last 5 years. Data were collected through a survey sent to each of the 50 U.S. State Health Departments. Forty-eight percent of the 50 states responded to the survey. From the results, we can conclude that there is currently no uniform description of what states expect of their state nurse directors, even though these individuals lead the largest portion of the public health workforce. The public and the public health system place a large, but often unwritten and unspoken, expectation on public health nurse leaders, but in recent years erosion has occurred in public health nursing in many states. Public health nursing is well positioned to provide leadership under health care reform. The challenge now facing public health nursing leaders is to maintain or create the infrastructure, as well as the organizational culture, to maximize these opportunities.

A random-effects model for analysis of infectious disease final-state data.

Ball (1986, Advances in Applied Probability 18, 289-310) presented an extension to the "General Epidemic Model" in which an individual's (random) infectious period could have any distribution whose Laplace transform could be specified. This paper describes the fitting of Ball's model to data on the final state of infection within households, and gives an intuitive mathematical derivation of the corresponding likelihood function. We extend the model in several ways, including an extension to allow for random-effects heterogeneity in disease transmission rate between individuals. We give an algorithm for the efficient numerical computation of maximum likelihood estimators of the transmission rates, and describe the assessment of goodness of model fit. The methodology is illustrated with recent survey data on outbreaks of Shigella sonnei in 102 households in Manchester, UK. The results are consistent with previous anecdotal evidence of the infectiousness and susceptibility of individuals within households as a function of age and sex.

Prevalence and distribution of bacteriophage phi Aa DNA in strains of Actinobacillus actinomycetemcomitans.

phi Aa is a bacteriophage that was originally isolated by induction of a lysogenic strain of the oral bacterium Actinobacillus actinomycetemcomitans. Since the discovery of phage phi Aa, additional phages infecting several other strains of A. actinomycetemcomitans have been identified. To determine the prevalence of phi Aa or phi Aa-related temperate phages in this species, a phi Aa-specific DNA probe was prepared to screen for homologous sequences among 42 strains of A. actinomycetemcomitans. Fourteen (33%) of the 42 strains examined contained DNA sequences that hybridized with the phage phi Aa probe. A bacteriophage designated phi Aa33384 was isolated by induction from one of the strains (ATCC 33384) that contained a sequence that hybridized with the phi Aa probe. The phi Aa probe hybridized with the DNA extracted from bacteriophage phi Aa33384. The distribution of the phage phi Aa sequence among A. actinomycetemcomitans serotypes was 5/13 (38%) of the serotype a strains, 0/16 (0%) of the serotype b strains, and 9/13 (69%) of the serotype c strains. The results of this investigation suggest that the target sequence prepared from the phage phi Aa genome is fairly common in the A. actinomycetemcomitans chromosome, and that the sequence is distributed among the A. actinomycetemcomitans serotypes in a seemingly nonrandom manner.

Artificial neural network comparison of expert and novice problem-solving strategies.

The successful strategies of second-year medical students were electronically captured from computer-based simulations in immunology and infectious disease and were used to train artificial neural networks for the rapid classification of subsequent students' and experts' strategies on these problems. Such networks could categorize problem solutions of other students as successful or nonsuccessful > 85% of the time. These neural networks, however, performed poorly (as low as 13%) when classifying experienced immunologists' or internists' successful performances, suggesting an ability to distinguish between novice and expert strategies. The neural networks also identified a group of students who framed the infectious disease problems correctly, but had difficulty discriminating between differential diagnoses.

Conjugal transfer of broad-host-range incompatibility group P and Q plasmids from Escherichia coli to Actinobacillus actinomycetemcomitans.

The first example of conjugal transfer of DNA from Escherichia coli to the periodontal pathogen Actinobacillus actinomycetemcomitans is presented. Derivatives of the incompatibility group P (IncP) plasmid RK2 successfully transferred from an E. coli donor to an A. actinomycetemcomitans recipient. The resulting A. actinomycetemcomitans transconjugants transferred the plasmids back to E. coli recipients. The IncP transfer functions were also used in trans to mobilize the IncQ plasmid pBK1 from E. coli to A. actinomycetemcomitans. The IncP and IncQ plasmids both transferred into A. actinomycetemcomitans at high frequencies (0.3 to 0.5 transconjugants per donor) and showed no gross deletions, insertions, or rearrangements. Determinations of MICs of various antibiotics for the A. actinomycetemcomitans transconjugant strains demonstrated the expression of ampicillin, chloramphenicol, and kanamycin resistance determinants.

Characterization and physical mapping of the genome of bacteriophage phi Aa from Actinobacillus actinomycetemcomitans.

The size, configuration and restriction map of Actinobacillus actinomycetemcomitans bacteriophage phi Aa DNA was determined by means of restriction endonuclease analysis. Digestion of the phi Aa DNA with restriction enzymes Hind III, Eco RI and Sal I produced 6, 5, and 4 fragments, respectively. Based upon the sum of the sizes of the restriction fragments of these enzymes, the DNA was estimated to be 47.2 kilobase pairs in length. A restriction map was constructed using Hind III and Sal I. Incubation with exonuclease Bal 31 for increasing lengths of time resulted in progressive hydrolysis of the DNA, as expected for a linear molecule. No sub-molar fragments or diffuse bands were observed in the agarose gels of the restriction endonuclease digests of the phi Aa DNA. Attempts at ligating the ends of the DNA were consistently unsuccessful. Therefore, we found no evidence for cohesive ends, a circular permutation of the genome or for headful packaging mechanism from a concatameric DNA precursor.

Identification of Actinobacillus actinomycetemcomitans: polymerase chain reaction amplification of lktA-specific sequences.

Actinobacillus actinomycetemcomitans has been strongly implicated in the etiology of localized juvenile periodontitis. Techniques used in the identification of this periodontal pathogen include cultural, biochemical, immunological and DNA hybridization analysis. In this study, we report the use of polymerase chain reaction (PCR) to amplify unique sequences of A. actinomycetemcomitans. Specific oligonucleotide primers LKT2 and LKT3 were designed to hybridize to the A. actinomycetemcomitans lktA gene, which encodes leukotoxin, a putative A. actinomycetemcomitans virulence factor. The LKT2 and LKT3 primers amplified lktA-specific sequences from all 12 A. actinomycetemcomitans strains tested. In another set of experiments, 13 other bacterial species, most of which are normal residents of the oral cavity, were tested with these primers. These PCR amplifications also contained 2 additional primers, RRN4 and RRN5, which served as positive controls; RRN4 and RRN5 were designed to amplify specific sequences of eubacterial 16S ribosomal DNA (rDNA). PCR amplifications of all bacterial species tested, including A. actinomycetemcomitans, yielded 16S rDNA-specific DNA fragments. Furthermore, each bacterial species tested, with the exception of A. actinomycetemcomitans, failed to amplify lktA sequences. The LKT and RRN primers were used in further PCR experiments to detect A. actinomycetemcomitans directly from gingival fluid samples. The results clearly demonstrate the simplicity, rapidity, specificity and accuracy of the LKT primers in the identification of A. actinomycetemcomitans.