Autophosphorylation at Thr279 of Entamoeba histolytica atypical kinase EhAK1 is required for activity and regulation of erythrophagocytosis

Phagocytosis plays a key role in survival and pathogenicity of Entamoeba histolytica. We have recently demonstrated that an atypical kinase EhAK1 is involved in phagocytosis in this parasite. It is recruited to the phagocytic cups through interaction with EhCaBP1. EhAK1 manipulates actin dynamics by multiple mechanisms including phosphorylation of G-actin. Biochemical analysis showed that EhAK1 is a serine/threonine kinase with broad ion specificity and undergoes multiple trans-autophosphorylation. Three autophosphorylation sites were identified by mass spectrometry. Out of these Thr279 appears to be involved in both autophosphorylation as well as substrate phosphorylation. Over expression of the mutant Thr279A inhibited erythrophagocytosis showing dominant negative phenotype. Multiple alignments of different kinases including alpha kinases displayed conserved binding sites that are thought to be important for function of the protein. Mutation studies demonstrated the importance of some of these binding sites in kinase activity. Binding studies with fluorescent-ATP analogs supported our prediction regarding ATP binding site based on sequence alignment. In conclusion, EhAK1 has multiple regulatory features and enrichment of EhAK1 at the site of phagocytosis stimulates trans-autophosphorylation reaction that increases kinase activity resulting in enhanced actin dynamics and phagocytosis. Some of the properties of EhAK1 are similar to that seen in alpha kinases.

Vitamin D deficiency and risk of postpartum tuberculosis among HIV-infected breastfeeding mothers in India

Some studies have associated low vitamin D levels with the risk of tuberculosis (TB), but its association in human immunodeficiency virus (HIV) infected mothers in a TB-endemic region has not been well studied. We conducted a nested 1:2 case-control study among HIV-infected mothers in western India to evaluate the association between maternal vitamin D levels and the risk of postpartum TB. Vitamin D insufficiency, moderate deficiency and severe deficiency were observed in a high proportion of HIV-infected mothers, but were not associated with the risk of postpartum TB.

The Exeter technique can lead to a lower incidence of leg-length discrepancy after total hip arthroplasty

We evaluated an operative technique, described by the Exeter Hip Unit, to assist accurate introduction of the femoral component. We assessed whether it led to a reduction in the rate of leg-length discrepancy after total hip arthroplasty (THA). A total of 100 patients undergoing THA were studied retrospectively; 50 were undertaken using the test method and 50 using conventional methods as a control group. The groups were matched with respect to patient demographics and the grade of surgeon. Three observers measured the depth of placement of the femoral component on post-operative radiographs and measured the length of the legs. There was a strong correlation between the depth of insertion of the femoral component and the templated depth in the test group (R = 0.92), suggesting accuracy of the technique. The mean leg-length discrepancy was 5.1 mm (0.6 to 21.4) pre-operatively and 1.3 mm (0.2 to 9.3) post-operatively. There was no difference between Consultants and Registrars as primary surgeons. Agreement between the templated and post-operative depth of insertion was associated with reduced post-operative leg-length discrepancy. The intra-class coefficient was R ≥ 0.88 for all measurements, indicating high observer agreement. The post-operative leg-length discrepancy was significantly lower in the test group (1.3 mm) compared with the control group (6.3 mm, p < 0.001). The Exeter technique is reproducible and leads to a lower incidence of leg-length discrepancy after THA.

Pasteurella multocida infected total knee arthroplasty: a case report and review of the literature

Pasteurella multocida is a rare cause of prosthetic joint infection. This infection generally follows significant animal contact, usually licks and scratches. We report a case of P multocida infection that was treated with linezolid with salvage of the implant. Linezolid is generally active against Gram-positive organisms only with the exception of Pasteurella, which is Gram-negative. We extensively review the previous reported cases of implant infection with P multocida.

Modifiable risk factors associated with tuberculosis disease in children in Pune, India

SETTING

India accounts for the largest burden of tuberculosis (TB) worldwide, with 26% of the world's cases.

OBJECTIVE

To assess the association between novel modifiable risk factors and TB in Indian children.

DESIGN

Cases were children aged ≤ 5 years with confirmed/probable TB based on World Health Organization definitions (definition 1). Controls were healthy children aged ≤ 5 years. Logistic regression was performed to estimate the adjusted odds ratio (aOR) of being a TB case given exposure, including indoor air pollution (IAP; exposure to tobacco smoke and/or biomass fuels) and vitamin D deficiency. Cases were re-analyzed according to a new consensus research definition of pediatric TB (definition 2).

RESULTS

Sixty cases and 118 controls were enrolled. Both groups had high levels of vitamin D deficiency (55% vs. 50%, P = 0.53). In multivariable analysis, TB was associated with household TB exposure (aOR 25.41, 95%CI 7.03-91.81), household food insecurity (aOR 11.55, 95%CI 3.33-40.15) and IAP exposure (aOR 2.67, 95%CI 1.02-6.97), but not vitamin D deficiency (aOR 1.00, 95%CI 0.38-2.66). Use of definition 2 reduced the number of cases to 25. In multivariate analysis, TB exposure, household food insecurity and IAP remained associated with TB.

CONCLUSIONS

Household TB exposure, exposure to IAP and household food insecurity were independently associated with pediatric TB.

Impact of maternal hepatitis B virus coinfection on mother-to-child transmission of HIV

OBJECTIVES

Despite high hepatitis B virus (HBV) endemicity in various resource-limited settings (RLSs), the impact of maternal HIV/HBV coinfection on infant health outcomes has not been defined. We aimed to assess the prevalence of HBV coinfection among HIV-infected pregnant women and its impact on HIV transmission and infant mortality.

METHODS

In this study, the seroprevalence of HBV coinfection was determined among HIV-infected pregnant women enrolled in the Six-Week Extended-Dose Nevirapine (SWEN) India trial. The impact of maternal HIV/HBV coinfection on mother-to-child transmission (MTCT) of HIV and infant mortality was assessed using univariate and multivariate logistic regression analysis.

RESULTS

Among 689 HIV-infected pregnant Indian women, 32 (4.6%) had HBV coinfection [95% confidence interval (CI) 3.4%, 5.3%]. HBV DNA was detectable in 18 (64%) of 28 HIV/HBV-coinfected women; the median HBV viral load was 155 copies/mL [interquartile range (IQR) < 51-6741 copies/mL]. Maternal HIV/HBV coinfection did not increase HIV transmission risk [adjusted odds ratio (aOR) 1.06; 95% CI 0.30, 3.66; P = 0.93]. Increased odds of all-cause infant mortality was noted (aOR 3.12; 95% CI 0.67, 14.57; P = 0.15), but was not statistically significant.

CONCLUSIONS

The prevalence of active maternal HBV coinfection in HIV-infected pregnant women in India was 4.6%. HIV/HBV coinfection was not independently associated with HIV transmission.

Clinicoradiologic correlation in adult patients diagnosed with novel influenza A (H1N1)

BACKGROUND

Influenza A(H1N1) infection affected Indian population in 2009. Patients needed ICU admission and monitoring.

OBJECTIVES

To describe and correlate clinical and radiographic features of Influenza A(H1N1) infection in patients hospitalised in Intensive care unit.

MATERIAL AND METHODS

Retrospective study of records of 100 RT-PCR confirmed patients with Influenza A(H1N1) infection from August 2009 to March 2010 was done. Each patient underwent an evaluation to determine clinical and radiographic features.

RESULTS

Mean age of the patients was 33.43 years (+/- 12.152) with maximum patients between 18-40 years, with 53% males and 43% females. Cough (96%), Fever (95%), breathlessness (83%), throat pain (34%), crepitations (69%), Tachypnoea (59%)were the prominent symptoms and signs. 61% (n = 63) had comorbid condition like pregnancy (n = 13,20.63%), Diabetes Mellitus (DM) (n = 12,19.05%), HT (n = 11,17.60%), Obesity (n = 10, 15.87%) and Rheumatic Valvular Heart Disease (RVHD) (n = 6,09.52%). Chest X ray was abnormal in 91% patients and normal in 09% pts. Bilateral findings were seen in 61.53% cases. Most common zones affected were lower zones (77.46%), then middle zones (71.42%), followed by upper zones (42.7%). Most common patterns were consolidation (64.83%), reticulonodular (24.17%) and nodular (10.98%). 27.47% had two, 21.97% had four, 19.78% had three,12.08% had six, 7.69% had five and 10.98% had single zone involvement. Fever, cough and tachypnoea were present in all 100% pts with nodular pattern while crepitations were observed in 79.66% cases of consolidation. Patchy consolidation was seen in comorbidities like pregnancy (n = 10) and obesity (n = 06), while reticulonodular pattern was observed in hypertensive patients (n = 06). Maximum number of deaths were between 21 and 30 years of age (60.71%). Total number of deaths were 28 with 60.71% (n = 17) deaths between 21 and 30 years of age. Deaths were more in presence of comorbidities like Pregnancy (n = 5, 17.85%), Hypertension (n = 4,14.28%), Diabetes (n = 3 10.21%) and RVHD (n = 3,10.71%), in presence of RLZ involvement (92.85%), RMZ (89.28%), LMZ (85.21%) and RUZ involvement (71.42%), with consolidation pattern (57.14%) followed by reticulonodular pattern (21.42%) and in presence of six zone involvement (36.37%) followed by four zone (35%) and then by three(33%) and two (32%) zone involvement. Mean duration of hospital stay was 9.1 days. 23% patients stayed for less than 5 days, 41% stayed between 9 and 14 days while only 7% required to stay for more than 15 days. 37% pts showed normal Xray at the time of discharge or death. 38% patients showed persistence of radiological lesion at discharge or death.

CONCLUSIONS

Young to middle age patients were commonly affected. Common comorbidities were Pregnancy, Diabetes, Hypertension, and Obesity and patients had fever, cough, breathlessness, tachypnoea, crepitations as common clinical features. Radiologically it was multizonal, bilateral disease with predominant lower zone involvement and common patterns were consolidation followed by reticulonodular and nodular. Patchy consolidation was more common in pregnancy and obesity while reticulonodular pattern was more in hypertensive patients. Fever, cough and tachypnoea were present in all 100% pts with nodular pattern. Crepitations were common in pts with consolidation. Clinical recovery preceded radiological recovery. Young to middle aged individuals died more. Deaths were more in presence of comorbidities like Pregnancy, HT, DM and RVHD, also with RLZ, RMZ, LMZ involvement and with consolidation pattern and with six zone involvement.

Clinical impact of the use of 16S rRNA sequencing method for the identification of "difficult-to-identify" bacteria in immunocompromised hosts

Molecular method of 16S rRNA sequencing is reported to be helpful in the accurate identification of organisms with ambiguous phenotypic profiles. We analyzed the use of 16S rRNA sequencing method to identify clinically significant, "difficult-to-identify" bacteria recovered from clinical specimens, and evaluated its role in patient management and consequent clinical outcome. Among the 172 "difficult-to-identify" bacteria recovered over a 4-year period, 140 were gram-positive cocci or gram-negative bacilli; identification by 16S rRNA did not play a role in the management of patients infected with these bacteria. From 32 patients, 33 "difficult-to-identify" gram-positive bacilli were identified; the organisms were mycobacteria, Nocardia, Tsukamurella, Rhodococcus, and Gordonia. In 24 patients for whom clinical data were available, results from the 16S rRNA sequencing method led to treatment change in 14 immunocompromised patients (including 7 hematopoietic stem cell recipients and 1 liver transplant recipient). Therapy was modified in 9 patients, initiated in 3 patients, and discontinued in 2 patients. Most patients' therapy was switched to oral antibiotics with discontinuation of intravascular catheters, facilitating early hospital discharge. All 14 patients were alive 30 days after infection onset. The present study demonstrates the clinical application of 16S rRNA sequencing method to identify "difficult-to-identify" mycobacteria and other gram-positive bacilli in clinical specimens, particularly in immunocompromised hosts.

Retrospective analysis of necropsy findings in patients of H1N1 and their correlation to clinical features

India reported its first case of H1N1 in July 2009 in Pune and since then, the number of reported cases and deaths exploded in India. Since very little data is available about histopathological findings in patients of H1N1 fatal cases in India, a retrospective chart analysis of necropsy findings of 15 cases of 2009 H1N1 fatal cases was performed. Common clinical features were fever, cough, and breathlessness followed by sore throat and rhinorrhea. Common lung findings were mononuclear cell infiltration, thick alveolar septae, intraalveolar hemorrhage. The other findings were congested pulmonary blood vessels, pulmonary edema, cytomegaly, fibrin accumulation and formation of eosinophilic membrane. These findings are suggestive of diffuse alveolar damage (DAD) and DAD with hemorrhage. All patients who underwent necropsy had radiographic findings suggestive of unilobar or multilobar pneumonia. This clinical finding can be correlated pathologically in these patients as all of them had either polymorphonuclear or mononuclear infiltrate. Furthermore, necrotizing pneumonitis pattern seen on these patients is the likely cause of mortality in these patients. Although clinical ARDS pattern was noted in all these patients, it was well correlated in lung pathology in all these cases.

Immunophenotypic Characterization of Benign and Malignant Prostatic Lesions

BACKGROUND

Biopsy diagnosis is the gold standard for differentiating benign and malignant prostatic enlargements. This study was aimed at supplementing biopsy diagnosis with immunophenotypic characters of prostatic lesions.

METHODS

Twenty five cases each of nodular hyperplasia and adenocarcinoma prostate were compared for their morphologic appearances and immunophenotyping, by studying antibodies to prostate specific antigen (PSA), transglutaminase, chromogranin and high molecular weight keratin, proliferating cell nuclear antigen, cell death (apoptosis) and neovascularisation (CD 34).

RESULTS

Markers of differentiation (PSA and transglutaminase) aided recognition of higher-grade tumours. PSA negativity avoided metaplasia being overcalled as carcinoma. Loss of basal cells around malignant prostatic acini as determined by high molecular weight keratin (HMWK), was useful in foci of atypical small acinar proliferation and in prostatic intraepithelial neoplasia. Assessment of proliferation indices identified subsets of tumours, within conventional morphologic Gleason's grades, with a higher growth fraction. Cell death determination and study of tumour vessels did not offer any improvement on morphology.

CONCLUSION

Immunophenotypic assessment helps in refining morphologic diagnosis of prostatic lesions. Differentiation and proliferation markers objectively assess tumour characteristics with their biologic growth potential and are recommended for diagnostic use. They also help in assessement of response to therapy.

Laparoscopic kidney transplantation: an initial experience

Laparoscopic donor nephrectomy has the advantages of less pain, early ambulation and shorter hospitalization compared to open donor nephrectomy. Kidney recipient surgery is, however, traditionally performed by open surgery. Our aim was to study feasibility and safety of laparoscopic kidney transplantation (LKT). After permission from Internal Review Board, LKT was performed in four patients. All kidneys were procured from deceased donors. Left kidney was used for LKT and transplanted in left iliac fossa while right kidney was used for standard open kidney transplantation (OKT). All transplantation procedures were performed successfully. Cold ischemia time varied between 4 h and 14 h. For LKT, mean time for anastomosis was 65 (range 62-72) min, mean operative time was 3.97 (range 3.5-5) h, mean blood loss was 131.25 mL (range 45-350) mL. Mean wound length was 7 cm in LKT group and 18.4 cm in OKT group. Delayed graft function was observed in one patient in each group. One patient was lost in OKT group due to posttransplant bacterial meningitis. At 6 months, both groups have comparable value of serum creatinine. In conclusion, LKT is technically feasible and safe. Long term outcome needs to be evaluated in a larger study.

Utility of in vitro proton magnetic resonance spectroscopy in aetiological characterisation of brain abscesses

PURPOSE

Brain abscesses often present an aetiological dilemma. Microscopy is insensitive and culture techniques are time consuming. Hence, a new rapid technique in vitro Proton Magnetic Resonance Spectroscopy (1HMRS) was evaluated for its usefulness in the identification of aetiology of brain abscesses.

MATERIALS AND METHODS

A total of 39 pus specimens from brain abscesses were subjected to in vitro 1HMRS. These pus specimens were also processed by conventional culture methods. The spectral patterns generated by in vitro 1HMRS were further correlated with culture results.

RESULTS

Pus specimens which showed the presence of anaerobes on culture revealed the presence of multiplet at 0.9 ppm (100%), lactate-lipid at 1.3 ppm (100%), acetate at 1.92 ppm (100%) and succinate at 2.4 ppm (75%). Pus specimens that revealed the presence of facultative anaerobes on culture showed a pattern B, i.e., the presence of lactate-lipid at 1.3 ppm (100%), acetate at 1.92 ppm (88.88%) along with the multiplet at 0.9 ppm (100%). Pattern C was seen in aerobic infection which showed the presence of lactate-lipid at 1.3 ppm (100%) along with the multiplet at 0.9 ppm. Pus from two tuberculous abscesses showed the complete absence of multiplet at 0.9 ppm.

CONCLUSIONS

We observed in this study that it was possible to differentiate bacterial and tuberculous brain abscesses using in vitro 1HMRS. Further, it was also possible to distinguish between aerobic and anaerobic brain abscesses on the basis of spectral patterns. In vitro 1HMRS of fungal and actinomycotic brain abscess are also presented for its unusual spectra.

Weissella confusa: an unexpected cause of vancomycin-resistant gram-positive bacteremia in immunocompromised hosts

We report the first case of Weissella confusa bacteremia in an allogeneic hematopoietic stem cell transplant patient. After engraftment and discharge, the patient returned with fever and graft failure and was started on an empiric regimen of aztreonam and vancomycin. A blood culture grew an alpha-hemolytic, gram-positive coccus forming pairs and chains, originally thought to be a viridans Streptococcus and a skin contaminant. The isolation of the organism from multiple blood cultures, and the presence of vancomycin resistance prompted identification and additional susceptibility testing. The RapID(™) Str panel, which has W. confusa in its database, provided multiple incorrect identifications. The MicroScan WalkAway 96 SI, using PC-20 or -29 panels, also did not identify this bacterium, because it is not in their database. The organism was identified as W. confusa by 16S rDNA sequencing. Antibiotic susceptibility determination by Etest revealed vancomycin resistance and daptomycin susceptibility. Therapy was changed to daptomycin, and the infection resolved. Additionally, W. confusa sepsis, with multiple positive blood cultures, developed in a patient in the burn unit at our medical center. The patient's blood cultures remained positive until vancomycin was discontinued and daptomycin therapy initiated. Infections with vancomycin-resistant, gram-positive cocci are emerging among immuno compromised hosts. Under appropriate circumstances, clinicians need to request that the laboratory perform susceptibility testing and accurate identification, by nucleic acid sequencing if necessary. Sequencing of 16S rDNA is an important tool in the accurate identification of unusual pathogens.

Rapid identification of non-sporing anaerobes using nuclear magnetic resonance spectroscopy and an identification strategy

PURPOSE

The non-sporing anaerobes cause a wide spectrum of infections. They are difficult to culture and their identification is tedious and time-consuming. Rapid identification of anaerobes is highly desirable. Towards this end, the potential of nuclear magnetic resonance (NMR) spectroscopy for providing a fingerprint within the proton spectrum of six genera belonging to anaerobes reflecting their characteristic metabolites has been investigated.

METHODS

NMR analysis was carried out using Mercury plus Varian 300 MHz (7.05 T) NMR spectrophotometer on six different anaerobes. These included Bacteroides fragilis, Prevotella melaninogenica, Prevotella denticola, Fusobacterium necrophorum, Peptococcus niger and Peptostreptococcus spp. After the NMR analysis (256/512 scans), the different peaks were noted. The eight pus specimens, which yielded pure culture of anaerobe, also were analysed similarly.

RESULTS

The major resonances of multiplex of amino acids/lipid at 0.9 ppm along with lactate/lipid at 1.3 ppm, acetate at 1.92 ppm and multiplex of lysine at 3.0 ppm remained constant to label the organism as an anaerobe. There was a difference found in the MR spectra of different genera and species. A simple algorithm was developed for the identification of the six different anaerobes studied. The MR spectra of the pure culture of the organism matched the MR spectra of pus from which the organism was isolated.

CONCLUSIONS

MR-based identification was of value in the identification of anaerobes. However, a larger database of the peaks produced by anaerobes needs to be created for identification of all genera and species. It could then have the potential of diagnosing an anaerobic infection in vivo and thus expedite management of deep-seated abscesses.

Cytomorphologic findings of hemangiopericytoma of the meninges: a case report

Hemangiopericytomas (HPCs) are tumors, constituting 2.5%, of soft tissue neoplasms. Meningeal hemangiopericytomas are rare non meningothelial mesenchymal tumors of the dura. They were classified as angioblastic meningiomas because of their similarity to meningiomas. However, these tumors are now regarded as distinct entities, akin to hemangiopericytoma elsewhere in the body. Few reports have addressed the fine needle aspiration (FNA) cytology of HPC. We present the cytological findings of one such rare case ofprimary meningeal hemangiopericytoma which metastasized to the lymph node. A 47 years male presented with cervical lymphadenopathy of 2 months duration. He was operated twice in the last 4 years and diagnosed atypical meningioma both times. The patient now also had spinal metastasis producing nerve root compression. Aspiration cytology of the node revealed cellular aspirate demonstrating round to oval cells with ample cytoplasm, round nuclei and inconspicuous nuclei. They showed a characteristic ferning out of blood vessels. Occasional mitosis was present. A diagnosis of malignant tumor of vascular origin was offered. Lymph node biopsy showed a characteristic histological picture of hemangiopericytoma described in other soft tissues. The cytology of this tumor is characteristic, but the rarity of the lesion, especially in metastatic sites makes diagnosis difficult unless a high index of suspicion is present. The recognition of the distinct cytological findings makes this possible. The case documents the role of FNA cytology in confirming HPC.