Health sequelae of human cryptosporidiosis-a 12-month prospective follow-up study.

To investigate long-term health sequelae of cryptosporidiosis, with especial reference to post-infectious irritable bowel syndrome (PI-IBS). A prospective cohort study was carried out. All patients with laboratory-confirmed, genotyped cryptosporidiosis in Wales, UK, aged between 6 months and 45 years of age, over a 2-year period were contacted. Five hundred and five patients agreed to participate and were asked to complete questionnaires (paper or online) at baseline, 3 and 12 months after diagnosis. The presence/absence of IBS was established using the Rome III criteria for different age groups. Two hundred and five of 505 cases completed questionnaires (40% response rate). At 12 months, over a third of cases reported persistent abdominal pain and diarrhoea, 28% reported joint pain and 26% reported fatigue. At both 3 and 12 months, the proportion reporting fatigue and abdominal pain after Cryptosporidium hominis infection was statistically significantly greater than after C. parvum. Overall, 10% of cases had sufficient symptoms to meet IBS diagnostic criteria. A further 27% met all criteria except 6 months' duration and another 23% had several features of IBS but did not fulfil strict Rome III criteria. There was no significant difference between C. parvum and C. hominis infection with regard to PI-IBS. Post-infectious gastrointestinal dysfunction and fatigue were commonly reported after cryptosporidiosis. Fatigue and abdominal pain were significantly more common after C. hominis compared to C. parvum infection. Around 10% of people had symptoms meriting a formal diagnosis of IBS following cryptosporidiosis. Using age-specific Rome III criteria, children as well as adults were shown to be affected.

Phylogenetic Analysis of Mycobacterium tuberculosis Strains in Wales by Use of Core Genome Multilocus Sequence Typing To Analyze Whole-Genome Sequencing Data.

An inability to standardize the bioinformatic data produced by whole-genome sequencing (WGS) has been a barrier to its widespread use in tuberculosis phylogenetics. The aim of this study was to carry out a phylogenetic analysis of tuberculosis in Wales, United Kingdom, using Ridom SeqSphere software for core genome multilocus sequence typing (cgMLST) analysis of whole-genome sequencing data. The phylogenetics of tuberculosis in Wales have not previously been studied. Sixty-six Mycobacterium tuberculosis isolates (including 42 outbreak-associated isolates) from south Wales were sequenced using an Illumina platform. Isolates were assigned to principal genetic groups, single nucleotide polymorphism (SNP) cluster groups, lineages, and sublineages using SNP-calling protocols. WGS data were submitted to the Ridom SeqSphere software for cgMLST analysis and analyzed alongside 179 previously lineage-defined isolates. The data set was dominated by the Euro-American lineage, with the sublineage composition being dominated by T, X, and Haarlem family strains. The cgMLST analysis successfully assigned 58 isolates to major lineages, and the results were consistent with those obtained by traditional SNP mapping methods. In addition, the cgMLST scheme was used to resolve an outbreak of tuberculosis occurring in the region. This study supports the use of a cgMLST method for standardized phylogenetic assignment of tuberculosis isolates and for outbreak resolution and provides the first insight into Welsh tuberculosis phylogenetics, identifying the presence of the Haarlem sublineage commonly associated with virulent traits.

Complete excision of the infrapatellar fat pad is associated with patellar tendon shortening after primary total knee arthroplasty.

BACKGROUND: Patella baja is a potentially disabling and difficult-to-treat complication following total knee arthroplasty (TKA). We investigated whether complete or partial excision of the fat pad has an effect on the length of the patellar tendon following TKA. METHODS: A retrospective review of patient radiographs was performed. One hundred and eleven consecutive patients who underwent primary TKA for osteoarthritis using the same components by two consultants were selected. Seventy-two patients underwent complete excision of the fat pad, whilst 39 had partial excision as per consultant practice. Patellar height was measured using the Caton-Deschamps Index (CDI) on immediate postoperative radiographs and at a minimum follow-up of 1 year. RESULTS: In the complete excision group, the mean CDI changed from 0.54 immediately postoperatively to 0.45 at a minimum follow-up of 1 year (p < 0.0001) indicating shortening of the patellar tendon, and eight patients reported anterior knee pain. The partial excision group's mean CDI changed from 0.76 to 0.75 (p = 0.231). An analysis of variance showed that the effect of complete fat pad excision on patella tendon length was significant, F(1, 109) = 15.273, p < 0.001. CONCLUSION: At a minimum follow-up of 1 year, the patellar tendon length shortened significantly in the group of patients with complete fat pad excision. With partial excision, there was no significant change in tendon length. Complete excision of the fat pad should therefore be avoided wherever possible in an attempt to avoid patella baja. LEVEL OF EVIDENCE: II.

Management of extreme patella baja using in-situ hamstring tendon autograft.

Successful total knee arthroplasty requires a functioning extensor mechanism. Patella baja following total knee arthroplasty can cause extensor mechanism dysfunction and produce poor outcomes. We present a case of severe patella tendon shortening following revision total knee arthroplasty with almost complete ankylosis of the distal pole of the patella to the proximal tibia. This resulted in effective extensor mechanism dysfunction with pain and severely limited knee flexion. We report a novel method of reconstruction of the patella tendon at the time of revision arthroplasty together with the one-year clinical outcome and review of the literature.

Target and nontarget effects of novel "triple-stacked" Bt-transgenic cotton 1: canopy arthropod communities.

Transgenic cotton varieties (Bollgard II) expressing two proteins (Cry1Ac and Cry2Ab) from Bacillus thuringiensis (Bt) have been widely adopted in Australia to control larvae of Helicoverpa. A triple-stacked Bt-transgenic cotton producing Cry1Ac, Cry2Ab, and Vip3A proteins (Genuity Bollgard III) is being developed to reduce the chance that Helicoverpa will develop resistance to the Bt proteins. Before its introduction, nontarget effects on the agro-ecosystem need to be evaluated under field conditions. By using beatsheet and suction sampling methods, we compared the invertebrate communities of unsprayed non-Bt-cotton, Bollgard II, and Bollgard III in five experiments across three sites in Australia. We found significant differences between invertebrate communities of non-Bt and Bt (Bollgard II and Bollgard III) cotton only in experiments where lepidopteran larval abundance was high. In beatsheet samples where lepidopterans were absent (Bt crops), organisms associated with flowers and bolls in Bt-cotton were more abundant. In suction samples, where Lepidoptera were present (i.e., in non-Bt-cotton), organisms associated with damaged plant tissue and frass were more common. Hence in our study, Bt- and non-Bt-cotton communities only differed when sufficient lepidopteran larvae were present to exert both direct and indirect effects on species assemblages. There was no overall significant difference between Bollgard II and III communities, despite the addition of the Vip gene in Bollgard III. Consequently, the use of Bollgard III in Australian cotton provides additional protection against the development of resistance by Helicoverpa to Bt toxins, while having no additional effect on cotton invertebrate communities.

Using semifield studies to examine the effects of pesticides on mobile terrestrial invertebrates.

Many farmers rely on regular pesticide applications to avoid losses from arthropod pests and the diseases they vector. However, widespread and injudicious use of pesticides is detrimental to the environment, poses a health risk, and undermines biocontrol services. Researchers are increasingly required to develop techniques to quantify the trade-offs and risks associated with pesticides. Laboratory studies, though useful for assessing short-term impacts (e.g., mortality), cannot detect longer-term or indirect effects that can potentially be assessed using semifield studies. Here we review the range and scope of studies that have used semifield methods for regulatory testing and risk assessment of pesticides and for understanding the community-level effects of pesticide use in agricultural landscapes. We include studies on target and nontarget species, with an emphasis on quantifying effects when the target species is highly mobile. We suggest improvements in the design and analysis of semifield studies to more effectively assess effects on highly mobile species.

Closed suction drains, reinfusion drains or no drains in primary total knee replacement?

INTRODUCTION: Controversy still surrounds the use of drains after total knee replacement (TKR). We compared closed suction drains, reinfusion drains and no drains by studying haemoglobin (Hb) levels, blood transfusion requirements and functional knee outcome scores in a single surgeon series. METHODS: A total of 102 consecutive primary TKRs were performed by the senior author between September 2006 and July 2008. All were cemented fixed bearing devices with patellar resurfacing. Of the 102 patients, 30 had closed suction drainage, 33 had an unwashed reinfusion drainage system and 39 had no drains. Data regarding pre and post-operative Hb and units transfused were gathered retrospectively. Pre and post-operative American Knee Society scores (AKSS) and Oxford knee scores (OKS) were recorded prospectively. RESULTS: The pre-operative Hb levels were comparable among the groups. There was no statistically significant difference in Hb level reduction or autologous transfusion rates among the groups. Pre-operative AKSS and OKS were statistically comparable in each group. There was no statistical difference between the improvement in AKSS knee and function scores in all three groups. There was a slightly smaller improvement in the OKS of the 'no drain' group. There were no complications of drain usage and no deep infections. No patient required manipulation under anaesthesia and range of movement outcomes were the same for each group. CONCLUSIONS: Our study does not support the use of either closed suction drains or reinfusion drains in primary elective TKR.

Functional relevance of patellofemoral thickness before and after unicompartmental patellofemoral replacement.

The aim of this study was to assess the increase in the anterior height of the knee after unicompartmental patellofemoral replacement and the impact of this increase on the range of motion and function of the knee. Twenty-eight patients (34 knees) who underwent patellofemoral replacement with FPV(TM) prosthesis between 2005 and 2009 were identified and retrospectively analyzed using chart and radiological review. Trochlear height and patellar thickness were measured combined and compared pre and postoperatively. The range of movement and functional outcome scores after 6-12 months follow-up were noted. The effect of increased postoperative anterior-posterior height of the knee on the range of motion was studied. Postoperative mean range of flexion of the knee joint was 116°. The mean Oxford knee score was 21 points. The mean American Knee Society Knee Score was 80 points for pain and 61 points for function. The trochlear height and patellar thickness were increased by 3.5 and 2.5 mms respectively, resulting in average total increase of 6mm in the anterior-posterior height of the knee. We found no relationship between range of motion and function of the knee and the increase in the anterior-posterior height. We found a negative correlation between increase in the anterior-posterior height and preoperative anterior-posterior height. FPV patellofemoral replacement results in correct anatomical reconstruction of the trochlear height rather than 'overstuffing' of the patellofemoral joint. There is an increase in anterior-posterior height of the knee but this does not affect range of movement or clinical outcome.

Clinical laboratory practices for detection and reporting of Cryptosporidium in community cases of diarrhoea in the United Kingdom, 2008.

To identify procedures employed by publicly funded clinical diagnostic laboratories in the United Kingdom (UK) for the detection of Cryptosporidium in community cases of diarrhoea, a telephone survey was conducted between August 2008 and January 2009 of all such laboratories that test stools from community-based patients. All 200 laboratories responded: 145 (72.5%) tested all stool samples for Cryptosporidium, while 55 (27.5%) applied selection criteria. There were country and regional differences in the proportion of laboratories selectively testing stools, which were significantly correlated with Cryptosporidium report rates to national surveillance (Spearman's rank correlation coefficient (rs)=0.61, degrees of freedom (df)=11, p=0.03). Understanding of laboratory practice is fundamental to interpreting trends in surveillance data, estimating disease burden and identifying outbreaks, as well as providing important background information against which changes and effects of new public health regulations can be measured.

Trichogramma (Hymenoptera: Trichogrammatidae) ecology in a tropical bt transgenic cotton cropping system: sampling to improve seasonal pest impact estimates in the Ord River Irrigation Area, Australia.

Trichogramma Westwood (Hymenoptera: Trichogrammatidae) cause high mortality rates in the potentially resistant pest species, Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae), and are considered integral to the resistance management plan for Bacillus thuringiensis transgenic cotton, Gossypium hirsutum L., production in the Ord River Irrigation Area (ORIA), Western Australia. Measured as percentage of parasitism, Trichogramma activity seems highly variable over time; yet, it contributes significantly to pest suppression at peak insect pest density. Environmental constraints on Trichogramma survival, especially insecticide applications, may limit their effectiveness. The decision to initiate insecticide applications in ORIA cotton crops is best delayed unless absolutely necessary to avoid disruption of Trichogramma impact on pests. Trichogramma disperse into young crops and display high intrinsic rates of increase effectively stifling Helicoverpa (Hardwick) population increase after initial egg lay during high-density years in the ORIA, and evidence suggests a possible preference for H. armigera host eggs.

Resuscitation-promoting factors are expressed in Mycobacterium tuberculosis-infected human tissue.

Resuscitation-promoting factors are small proteins found in many high G+C Gram-positive organisms. In picomolar concentrations in vitro they promote the emergence from dormancy and shorten the lag phase of growth of small inocula of responsive bacteria. Mycobacterium tuberculosis has five rpf gene orthologues all of which are expressed during in vitro growth. Rpfs may play a role in dormancy or reactivation of tubercle bacilli in vivo, and could be a potential target for chemotherapeutic intervention: however it is not known whether they are expressed by M. tuberculosis in vivo in the context of human infection. The work presented here demonstrates that Rpf expression can be detected in human tissues infected with M. tuberculosis and describes the pattern of this expression using immunocytochemistry with anti-Rpf antibodies.

Causes of failure of the Kinemax Plus total knee replacement in the first five years.

In order to investigate whether any single batch of polyethylene inserts was responsible for premature failure of total knee replacements (TKR), we performed a retrospective database review of 1133 consecutive primary Kinemax Plus TKR performed by 2 surgical teams between January 1992 and January 2001 at our institution. Cases re-operated in any way within 5 years of the index arthroplasty were identified, case notes studied and radiographs reviewed. The causes contributing to the premature failure of the implants were identified where possible and the polyethylene lot numbers were recorded. Nineteen cases were known to have been revised, 7 cases for deep infection of the prosthesis and 12 for aseptic failure. In 10 cases, an identifiable technical error had contributed to the early failure of the implant. In 4 of these cases, there was inadequate tissue balancing in patients with a significant pre-operative valgus deformity. In 2 cases, the tibial base plate was inserted in a varus mal-alignment. There was one extended tibial component, one internally rotated femoral component, one oversized femoral component and one femoral component with inadequate fixation. Two further cases failed aseptically, one with a fracture of the medial tibial plateau and one idiopathic. The lot numbers of the polyethylene inserts were all different. This study confirms that the premature failure rate of the Kinemax Plus TKR is low. Although a "bad batch" of polyethylene has been suggested as a cause for early failure in TKR, in this series, surgical error was the predominant cause.

Biofilm formation in medical device-related infection.

Medical device-associated infections, most frequently caused by coagulase-negative staphylococci, especially Staphylococcus epidermidis, are of increasing importance in modern medicine. Regularly, antimicrobial therapy fails without removal of the implanted device. The most important factor in the pathogenesis of medical device-associated staphylococcal infections is the formation of adherent, multilayered bacterial biofilms. There is urgent need for an increased understanding of the functional factors involved in biofilm formation, the regulation of their expression, and the interaction of those potential virulence factors in device related infection with the host. Significant progress has been made in recent years which may ultimately lead to new rational approaches for better preventive, therapeutic, and diagnostic measures.

A rapid single-step multiplex method for discriminating between Trichogramma (Hymenoptera: Trichogrammatidae) species in Australia.

Inaccurate species identification confounds insect ecological studies. Examining aspects of Trichogramma ecology pertinent to the novel insect resistance management strategy for future transgenic cotton, Gossypium hirsutum L., production in the Ord River Irrigation Area (ORIA) of Western Australia required accurate differentiation between morphologically similar Trichogramma species. Established molecular diagnostic methods for Trichogramma identification use species-specific sequence difference in the internal transcribed spacer (ITS)-2 chromosomal region; yet, difficulties arise discerning polymerase chain reaction (PCR) fragments of similar base pair length by gel electrophoresis. This necessitates the restriction enzyme digestion of PCR-amplified ITS-2 fragments to readily differentiate Trichogramma australicum Girault and Trichogramma pretiosum Riley. To overcome the time and expense associated with a two-step diagnostic procedure, we developed a "one-step" multiplex PCR technique using species-specific primers designed to the ITS-2 region. This approach allowed for a high-throughput analysis of samples as part of ongoing ecological studies examining Trichogramma biological control potential in the ORIA where these two species occur in sympatry.

Metal-specific differences in levels of DNA damage caused by synovial fluid recovered at revision arthroplasty.

Previous research has shown an increase in chromosomal aberrations in patients with worn implants. The type of aberration depended on the type of metal alloy in the prosthesis. We have investigated the metal-specific difference in the level of DNA damage (DNA stand breaks and alkali labile sites) induced by culturing human fibroblasts in synovial fluid retrieved at revision arthroplasty. All six samples from revision cobalt-chromium metal-on-metal and four of six samples from cobalt-chromium metal-on-polyethylene prostheses caused DNA damage. By contrast, none of six samples from revision stainless-steel metal-on-polyethylene prostheses caused significant damage. Samples of cobalt-chromium alloy left to corrode in phosphate-buffered saline also caused DNA damage and this depended on a synergistic effect between the cobalt and chromium ions. Our results further emphasise that epidemiological studies of orthopaedic implants should take account of the type of metal alloy used.

Lipoma arborescens of the knee.

Lipoma arborescens (diffuse articular lipomatosis) is a rare, benign intra-articular lesion of unknown aetiology. It is characterised by villous proliferation of the synovium and diffuse replacement of the subsynovial tissue by mature fat cells. It forms part of the differential diagnosis for a slowly progressive chronically swollen knee. We present a very rare case of bilateral involvement of the knee and discuss the symptoms, diagnosis and treatment of this condition.

An unusual lymphocytic perivascular infiltration in tissues around contemporary metal-on-metal joint replacements.

BACKGROUND: Metal-on-metal bearing surfaces have been reintroduced for use during total hip replacement. To assess tissue reactions to various types of articulations, we studied the histological appearance of periprosthetic tissues retrieved from around metal-on-metal and metal-on-polyethylene total hip replacements and compared these findings with the appearance of control tissues retrieved at the time of primary arthroplasty. METHODS: Periprosthetic tissues were obtained at the time of revision of twenty-five cobalt chromium-on-cobalt chromium, nine cobalt chromium-on-polyethylene, and ten titanium-on-polyethylene total hip arthroplasties. Control tissues were obtained from nine osteoarthritic hips at the time of primary total hip arthroplasty. Each tissue sample was processed for routine histological analysis, and sections were stained with hematoxylin and eosin. Quantitative stereological analysis was performed with use of light microscopy. RESULTS: Tissue samples obtained from hips with metal-on-metal implants displayed a pattern of well-demarcated tissue layers. A prominent feature, seen in seventeen of twenty-five tissue samples, was a pattern of perivascular infiltration of lymphocytes. In ten of the tissue samples obtained from hips with metal-on-metal prostheses, there was also an accumulation of plasma cells in association with macrophages that contained metallic wear-debris particles. The surfaces of tissues obtained from hips with metal-on-metal prostheses were more ulcerated than those obtained from hips with other types of implants, particularly in the region immediately superficial to areas of perivascular lymphocytic infiltration. The lymphocytic infiltration was more pronounced in samples obtained at the time of revision because of aseptic failure than in samples retrieved at the time of autopsy or during arthrotomy for reasons other than aseptic failure. Total-joint-replacement and surface-replacement designs of metal-on-metal prostheses were associated with similar results. Tissue samples obtained from hips with metal-on-polyethylene implants showed far less surface ulceration, much less distinction between tissue layers, no pattern of lymphocytic infiltration, and no plasma cells. The inflammation was predominantly histiocytic. Tissues retrieved from hips undergoing primary joint replacement showed dense scar tissue and minimal inflammation. CONCLUSIONS AND CLINICAL RELEVANCE: The pattern and type of inflammation seen in periprosthetic tissues obtained from hips with metal-on-metal and metal-on-polyethylene implants are very different. At the present time, we do not know the prevalence or clinical implications of these histologic findings, but we suggest that they may represent a novel mode of failure for some metal-on-metal joint replacements.

The optimum knee flexion angle for skyline radiography is thirty degrees.

There is wide variation in practice among orthopaedic surgeons regarding the use of skyline tangential patellar radiographs of the patellofemoral joint in patients with anterior knee pain. Various techniques are available for taking such radiographs and numerous radiologic parameters can be measured from them. There is no information as to which knee flexion angle is superior when taking skyline radiographs. The purpose of the current study was to compare the results of skyline radiographs taken at 30 degrees, 50 degrees, and 90 degrees knee flexion. Sixty-seven knees were studied prospectively. All radiographs were made anonymous and then were studied in random order by two observers. Five recognized patellofemoral parameters were recorded. All the parameters studied were measured most reproducibly when measured from the radiograph taken at 30 degrees knee flexion. The parameters were least reproducible when measured from the radiograph taken at 90 degrees knee flexion. In terms of detecting abnormality of the parameters measured, the radiographs taken at 30 degrees and 50 degrees were similar. The radiograph taken at 90 degrees knee flexion detected the fewest abnormalities. Skyline radiographic examination of the patellofemoral joint should be a mandatory part of the investigation of all knee problems. One radiograph, ideally taken at 30 degrees knee flexion, offers the best means of assessing the patellofemoral joint. There is no benefit to requesting multiple images at different angles of knee flexion.

Outbreak of isoniazid resistant tuberculosis in north London.

BACKGROUND: A description is given of a major outbreak of isoniazid monoresistant tuberculosis (TB) chiefly in north London, including prisons. The earliest case was diagnosed in 1995 with most cases appearing after 1999. METHODS: Confirmation of a local cluster of cases was confirmed by restriction fragment length polymorphism (RFLP IS6110) typing or "rapid epidemiological typing" (RAPET). Further cases were found by retrospective analysis of existing databases, prospective screening of new isolates, and targeted epidemiological case detection including questionnaire analysis. RESULTS: By the end of 2001, 70 confirmed cases in London had been linked with a further 13 clinical cases in contacts and nine epidemiologically linked cases outside London. The epidemic curve suggests that the peak of the outbreak has not yet been reached. Cases in the outbreak largely belong to a social group of young adults of mixed ethnic backgrounds including several individuals from professional/business backgrounds. Compared with other cases of TB reported to the enhanced surveillance scheme in London during 1999-2001, the cases are more likely to be of white (26/70 (37%) v 1308/7666 (17%)) or black Caribbean ethnicity (17/70 (24%) v 312/7666 (4%)), born in the UK (41/70 (59%) v 1335/7666 (17%)), and male (52/70 (74%) v 4195/7666 (55%)). Drug misuse and/or prison detention are factors common to many cases. CONCLUSIONS: The investigation of the outbreak revealed significant problems on an individual patient and population based level including difficulties with contact tracing, compliance, and the risk of developing multidrug resistance. This incident has demonstrated the value of molecular strain typing in investigating an extensive outbreak of TB. This is the first documented outbreak involving a UK prison.