Urinary Vacuolar Casts Are a Unique Type of Casts in Advanced Proteinuric Glomerulopathies

Key Points

Vacuolar casts are a distinct type of casts identifiable by urinary sediment microscopy. Identification of urinary vacuolar casts is associated with the presence of an advanced and severe form of a proteinuric glomerular disease.

Background

Identification of casts by urinary sediment microscopy is a valuable diagnostic clinical tool for the evaluation of kidney disease. Vacuolar casts are an unrecognized unique type of casts characterized by the presence of nonpolarizable, clear vesicles of various sizes contained within a cast matrix, different from lipid casts, erythrocyte casts, or any other casts. We aimed to gain better understanding of the clinical relevance of these casts by establishing a multinational collaborative group to search for cases in which vacuolar casts were identified.

Methods

Leveraging an educational social media platform, we conducted a multinational observational study extracting cases of patients who presented with urinary vacuolar casts during evaluation for impaired kidney function. Parameters assessed included degree of proteinuria and kidney dysfunction, clinical and histopathological diagnosis, and severity of renal parenchymal scarring on biopsy. A control group of patients without vacuolar casts was included for comparison.

Results

Forty-six patients with urinary vacuolar casts were compiled from six countries. Nephrotic range proteinuria (82%), glomerular etiology (98%), and advanced CKD stage (62% 3B-5) were salient features. Histopathological diagnosis was available in 26 (57%) patients. Combining clinical and pathological diagnoses, diabetic nephropathy (48%), arterionephrosclerosis (30%), podocytopathies (15%), and proliferative glomerulonephritides (15%) accounted for most patients. Vacuolization of tubules or podocytes was present in 61% of the specimens. When compared with patients with histopathological diagnoses in which vacuolar casts were not found (n =186), patients with vacuolar casts more frequently had a glomerular etiology (100% versus 71%, P = 0.002), had greater proteinuria (median urine protein-to-creatinine 10.3 versus 2.2 g/g, P < 0.001), and had greater proportion of patients with ≥30% glomerular obsolescence (46% versus 20%, P = 0.003).

Conclusions

Thus, urinary vacuolar casts are strongly associated with advanced glomerulopathies with severe proteinuria. Future studies should examine their origin, composition, and prognostic value.

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Incidence and outcomes of acute kidney injury including hepatorenal syndrome in hospitalized patients with cirrhosis in the US

BACKGROUND & AIMS

Acute kidney injury (AKI) in cirrhosis is common and associated with high morbidity, but the incidence rates of different etiologies of AKI are not well described in the US. We compared incidence rates, practice patterns, and outcomes across etiologies of AKI in cirrhosis.

METHODS

We performed a retrospective cohort study of 11 hospital networks, including consecutive adult patients admitted with AKI and cirrhosis in 2019. The etiology of AKI was adjudicated based on pre-specified clinical definitions (prerenal/hypovolemic AKI, hepatorenal syndrome [HRS-AKI], acute tubular necrosis [ATN], other).

RESULTS

A total of 2,063 patients were included (median age 62 [IQR 54-69] years, 38.3% female, median MELD-Na score 26 [19-31]). The most common etiology was prerenal AKI (44.3%), followed by ATN (30.4%) and HRS-AKI (12.1%); 6.0% had other AKI, and 7.2% could not be classified. In our cohort, 8.1% of patients received a liver transplant and 36.5% died by 90 days. The lowest rate of death was observed in patients with prerenal AKI (22.2%; p <0.001), while death rates were higher but not significantly different from each other in those with HRS-AKI and ATN (49.0% vs. 52.7%; p = 0.42). Using prerenal AKI as a reference, the adjusted subdistribution hazard ratio (sHR) for 90-day mortality was higher for HRS-AKI (sHR 2.78; 95% CI 2.18-3.54; p <0.001) and ATN (sHR 2.83; 95% CI 2.36-3.41; p <0.001). In adjusted analysis, higher AKI stage and lack of complete response to treatment were associated with an increased risk of 90-day mortality (p <0.001 for all).

CONCLUSION

AKI is a severe complication of cirrhosis. HRS-AKI is uncommon and is associated with similar outcomes to ATN. The etiology of AKI, AKI stage/severity, and non-response to treatment were associated with mortality. Further optimization of vasoconstrictors for HRS-AKI and supportive therapies for ATN are needed.

IMPACT AND IMPLICATIONS

Acute kidney injury (AKI) in cirrhosis carries high morbidity, and management is determined by the etiology of injury. However, a large and well-adjudicated multicenter database from US centers that uses updated AKI definitions is lacking. Our findings demonstrate that acute tubular necrosis and hepatorenal syndrome have similar outcomes (∼50% mortality at 90 days), though hepatorenal syndrome is uncommon (12% of all AKI cases). These findings represent practice patterns at US transplant/tertiary centers and can be used as a baseline, presenting the situation prior to the adoption of terlipressin in the US.

PUF60-related developmental disorder: A case series and phenotypic analysis of 10 additional patients with monoallelic PUF60 variants

PUF60-related developmental disorder (also referred to as Verheij syndrome), resulting from haploinsufficiency of PUF60, is associated with multiple congenital anomalies affecting a wide range of body systems. These anomalies include ophthalmic coloboma, and congenital anomalies of the heart, kidney, and musculoskeletal system. Behavioral and intellectual difficulties are also observed. While less common than other features associated with PUF60-related developmental disorder, for instance hearing impairment and short stature, identification of specific anomalies such as ophthalmic coloboma can aid with diagnostic identification given the limited spectrum of genes linked with this feature. We describe 10 patients with PUF60 gene variants, bringing the total number reported in the literature, to varying levels of details, to 56 patients. Patients were recruited both via locally based exome sequencing from international sites and from the DDD study in the United Kingdom. Eight of the variants reported were novel PUF60 variants. The addition of a further patient with a reported c449-457del variant to the existing literature highlights this as a recurrent variant. One variant was inherited from an affected parent. This is the first example in the literature of an inherited variant resulting in PUF60-related developmental disorder. Two patients (20%) were reported to have a renal anomaly consistent with 22% of cases in previously reported literature. Two patients received specialist endocrine treatment. More commonly observed were clinical features such as: cardiac anomalies (40%), ocular abnormalities (70%), intellectual disability (60%), and skeletal abnormalities (80%). Facial features did not demonstrate a recognizable gestalt. Of note, but remaining of unclear causality, we describe a single pediatric patient with pineoblastoma. We recommend that stature and pubertal progress should be monitored in PUF60-related developmental disorder with a low threshold for endocrine investigations as hormone therapy may be indicated. Our study reports an inherited case with PUF60-related developmental disorder which has important genetic counseling implications for families.

Refractoriness of Hyperkalemia and Hyperphosphatemia in Dialysis-Dependent AKI Associated with COVID-19

Background

Persistent hyperkalemia (hyperK) and hyperphosphatemia (hyperP) despite renal replacement therapy (RRT) was anecdotally reported in COVID-19 and acute kidney injury (AKI) requiring RRT (CoV-AKI-RRT). However, observation bias could have accounted for the reports. Thus, we systematically examined the rate and severity of hyperK and hyperP in patients with CoV-AKI-RRT in comparison with the pre-COVID-19 era.

Methods

We identified patients with CoV-AKI-RRT treated with sustained low-efficiency dialysis (SLED) for ≥2 days in March-April 2020. As pre-COVID-19 control, we included patients with AKI treated with SLED in December 2019. We examined the rates of hyperK (serum potassium [sK] ≥5.5 mEq/L), severe hyperK (sK ≥6.5 mEq/L), hyperP (serum phosphate [sP] ≥4.5 mg/dl), and moderate or severe hyperP (sP ≥7-10 and >10 mg/dl, respectively) as %SLED-days with an event.

Results

Along the duration of SLED, the incidence of hyperK was greater in CoV-AKI-RRT (n=64; mean 19%±2% versus 14%±3% SLED-days, P=0.002) compared with control (n=60). The proportion of patients with one or more event of severe hyperK was greater in CoV-AKI (33% versus 7%, P<0.001). The incidence of hyperP was similar between groups (mean 56%±4% versus 53%±5% SLED-days, P=0.49). However, the proportion of patients with one or more event of moderate and severe hyperP was greater in CoV-AKI-RRT (86% versus 60%, P=0.001, and 50% versus 18%, P<0.001, respectively). Among those with CoV-AKI-RRT, sK and sP correlated with lactate dehydrogenase (LDH; r=0.31, P=0.04, and r=0.31, P=0.04, respectively), whereas hyperP also correlated with shorter SLED runs (hours/run; r=-0.27, P=0.05).

Conclusions

Refractory hyperK and hyperP were more frequent in CoV-AKI-RRT compared with the pre-COVID-19 era. Because of the correlation of sK and sP with higher LDH and sP with shorter SLED runs, intracellular ion release from cell injury due to cytokine storm and RRT interruptions may account for the findings.

Concomitant Identification of Muddy Brown Granular Casts and Low Fractional Excretion of Urinary Sodium in AKI

Background

Fractional excretion of urinary sodium (FENa) is a widely utilized clinical test to evaluate acute kidney injury (AKI). A low FENa (<1%) is deemed consistent with prerenal azotemia and inconsistent with acute tubular injury (ATI). Muddy brown granular casts (MBGC) on microscopic examination of urinary sediment (MicrExUrSed) are highly suggestive of ATI. We hypothesized that there is poor concordance between the presence of MBGC and FENa in ATI.

Methods

We conducted a prospective observational study in patients with AKI seen during inpatient consultation. We extracted patients who underwent assessment of percentage of low power fields (LPFs) with MBGC by MicrExUrSed and concomitant measurement of FENa. Diagnostic concordance between MBGC and FENa and their individual prognostic value were examined.

Results

Our cohort included 270 patients, 111 (41%) of whom were women. Median age was 61 years (range 27-92 years), and median serum creatinine was 3.7 mg/dl ( range1.2-22.0 mg/dl). MBGC were found in 49% (133/270). FENa <1% (inconsistent with ATI) was found in 50/133 (38%), 38/115 (33%), and 16/45 (36%) of those with >0%, ≥10%, and ≥50% LPFs with MBGC, respectively. Concordance between FENa and MBGC for ATI diagnosis was deemed fair (estimated κ-coefficient=0.2), and poor (κ=-0.11) within a subgroup of patients with preexisting chronic kidney disease (n=139). In patients with biopsy-proven ATI (n=49), MBGC had 100% specificity and 100% positive predictive value for ATI. MBGC were associated with greater risk for ≥50% increase in creatinine from baseline at discharge (acute kidney disease [AKD]).

Conclusions

About two of five patients with MBGC identified by MicrExUrSed presented with FENa <1%. Presence of MBGC was consistent with ATI, as verified by biopsy, and were predictive of AKD. These data suggest that the sole reliance in low FENa to exclude ATI should be abandoned, and MicrExUrSed should be pursued for AKI diagnosis.

Diagnostic Utility of Serial Microscopic Examination of the Urinary Sediment in Acute Kidney Injury

Background

Microscopic examination of the urinary sediment (MicrExUrSed) is an established diagnostic tool for AKI. However, single inspection of a urine specimen during AKI is a mere snapshot affected by timing. We hypothesized that longitudinal MicrExUrSed provides information otherwise not identified in a single inspection.

Methods

MicrExUrSed was undertaken in patients with AKI stage ≥2 and suspected intrinsic cause of AKI seen for nephrology consultation over a 2-year period. MicrExUrSed was performed on the day of consultation and repeated at a second (2-3 days later) and/or third (4-10 days later) interval. Cast scores were assigned to each specimen. Chawla scores (CS) 3-4 and Perazella scores (PS) 2-4 were categorized as consistent with acute tubular injury (ATI), whereas CS 1-2 and PS 0-1 were categorized as nondiagnostic for ATI (non-ATI). Nonrecovering AKI was defined as a rise in serum creatinine (sCr) ≥0.1 mg/dl between microscopy intervals.

Results

At least two consecutive MicrExUrSed were performed in 121 patients (46% women, mean age 61±14, mean sCr at consult of 3.3±1.9 mg/dl). On day 1, a CS and PS consistent with non-ATI was assigned to 64 (53%) and 70 (58%) patients, respectively. After a subsequent MicrExUrSed, CS and PS changed to ATI in 14 (22%) and 16 (23%) patients. Thus, 20%-24% of patients only revealed evidence of ATI after serial MicrExUrSed was performed. Patients with nonrecovering AKI were more likely to change their PS to the ATI category (odds ratio, 5.8; 95% CI, 1.7 to 19.3; P=0.005 and positive likelihood ratio, 2.0; 95% CI, 1.3 to 2.9).

Conclusions

Serial MicrExUrSed revealed diagnostic findings of ATI otherwise not identified in a single examination. A repeat MicrExUrSed may be warranted in patients AKI of unclear etiology that are not recovering.

Acute Kidney Injury Associated with Coronavirus Disease 2019 in Urban New Orleans

Background

AKI is a manifestation of COVID-19 (CoV-AKI). However, there is paucity of data from the United States, particularly from a predominantly black population. We report the phenotype and outcomes of AKI at an academic hospital in New Orleans.

Methods

We conducted an observational study in patients hospitalized at Ochsner Medical Center over a 1-month period with COVID-19 and diagnosis of AKI (KDIGO). We examined the rates of RRT and in-hospital mortality as outcome measures.

Results

Among 575 admissions (70% black) with COVID-19 [173 (30%) to an intensive care unit (ICU)], we found 161 (28%) cases of AKI (61% ICU and 14% general ward admissions). Patients were predominantly men (62%) and hypertensive (83%). Median body mass index (BMI) was higher among those with AKI (34 versus 31 kg/m2, P<0.0001). AKI over preexisting CKD occurred in 35%. Median follow-up was 25 (1–45) days. The in-hospital mortality rate for the AKI cohort was 50%. Vasopressors and/or mechanical ventilation were required in 105 (65%) of those with AKI. RRT was required in 89 (55%) patients. Those with AKI requiring RRT (AKI-RRT) had higher median BMI (35 versus 33 kg/m2, P=0.05) and younger age (61 versus 68, P=0.0003). Initial values of ferritin, C-reactive protein, procalcitonin, and lactate dehydrogenase were higher among those with AKI; and among them, values were higher for those with AKI-RRT. Ischemic acute tubular injury (ATI) and rhabdomyolysis accounted for 66% and 7% of causes, respectively. In 13%, no obvious cause of AKI was identified aside from COVID-19 diagnosis.

Conclusions

CoV-AKI is associated with high rates of RRT and death. Higher BMI and inflammatory marker levels are associated with AKI as well as with AKI-RRT. Hemodynamic instability leading to ischemic ATI is the predominant cause of AKI in this setting.

Physical restraint: perceptions of nurse managers, registered nurses and healthcare assistants

AIM

To examine the perceptions of nurse managers, registered nurses and healthcare assistants of physical restraint use on older people in a long-term care setting in the Republic of Ireland.

BACKGROUND

The use of physical restraint, although controversial, persists in long-term care settings, despite recommendations for restraint-free environments. Perception and attitude of staff can influence use of physical restraint.

METHODS

A descriptive cross-sectional design was used. A total of 250 nursing and healthcare assistant staff were recruited. A questionnaire incorporating demographics and the Perceptions of Restraint Use Questionnaire was used. Descriptive and inferential statistical analyses were conducted.

RESULTS

Mean age of respondents (n = 156) was 41 years, and the majority were female. Overall, a low level of importance was attached to the use of restraint. Nurse managers and registered nurses compared favourably with healthcare assistants who attached a higher importance to use of restraint. Across all three staff groups, greatest importance was attached to the use of physical restraint for reducing falls, followed by prevention of treatment interference. Restraint was least favoured as a means of impairment management. Education was not an explanatory factor in perceived importance of physical restraint use.

CONCLUSION

Nurse managers and registered nurses are unlikely to use physical restraint. However, there is concern regarding perception of healthcare assistants on use of restraint.

IMPLICATIONS FOR NURSING AND HEALTH POLICY

Results from this study compare favourably with those in countries that have no policy on physical restraint use. Educational programmes alone are insufficient to address use of physical restraint. Attention to skill mix with adequate support for healthcare assistants in long-term care settings is recommended.

Abstract P3-01-07: Metformin has an additive effect to cisplatin in triple negative breast cancer cells with high lactate dehydrogenase B (LDHB) expression

Background;

Glycolysis is one of the major metabolic pathways in cancer cells. The conversion of glucose to lactate in the presence of oxygen is a critical aerobic pathway that allows cancer cells to proliferate rapidly and the amount of lactate produced is correlated with tumor aggressiveness. Moreover, the increase in glycolysis is partially mediated by hypoxia-inducible transcription factor (HIF-1) and a metabolic enzyme, lactate dehydrogenase B (LDHB). However, the mechanism behind this metabolic shift is not well understood. Metformin reduces the overall risk of cancer incidence by 31%, improves cancer-related mortality and enhances response to chemotherapy in diabetic patients pre-operatively. This study aimed to evaluate metabolism in triple negative breast cancer.

Methods;

Breast cancer cell lines (estrogen receptor positive MCF7 and triple negative MDA-MB 231 and MDA-MB468) were analysed for protein expression by western blotting and mRNA expression by qRT-PCR with or without cisplatin and metformin. To study the biological mechanism, we evaluated cell growth using proliferation assay in the presence of metformin and cisplatin. The contribution of LDHB to glycolysis was evaluated using MDA-MB-231 and MDA-MB468 cell lines.

Results;

We first examined the basal expression levels of LDHB and HIF1a in these cancer cell lines. LDHB expression was high in MDA-MB 231, and HIF1α was high in MDA-MB468. Both metformin and cisplatin treatment resulted in the down-regulation of LDHB and HIF1α in MDA-MB231, metformin led to downregulation of LDHB in MDA-MB 468, while MCF7 demonstrated no significant changes. Inhibition of cell proliferation was dose-dependent and significant at low concentrations of cisplatin and metformin in only MDA-MB468 but not in MCF7 and MDA-MB231. The combination of cisplatin in with metformin had an added inhibitory effect on cell proliferation in these MD-MB231 cells.

Conclusion;

These studies suggest that combination treatment of metformin and cisplatin have potent anticancer activity in LDHB highly expressed triple negative breast cancer cells. Identification of a new targeted therapeutic approach could contribute to the new therapy to the breast cancer patients.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P3-01-07.

Abstract P4-01-22: Measurement of tumour lesion glycolysis by FDG-PET in triple negative breast cancer

Background:

Triple negative breast cancer (TNBC) has been associated with a high glycolytic rate. As a surrogate measure, the SUV of FDG uptake is found to be higher both in the TNBC and her2 positive phenotypes. Tumour lesion glycolysis (TLG) is a product of the mean SUV value and tumour volume. We wished to evaluate the role of combined volume and metabolic measurements of glycolysis in patients with TNBC.

Methods: 300 FDG-PET scans were performed in patients with breast cancer, of whom 25 were found to have TNBC over a 4 year period, in 19 patients there were suitable lesions identified for analysis. Patients were scanned on the same Siemens PET/CT scanner in the local hospital, static images were acquired 60 minutes post-injection. SUV was corrected for injected activity and body weight, TLGMAX50 was also calculated considering SUV50 isocontour instead of SUV mean. ∑TLG was the sum of TLG for an individual patient.

Results: 117 lesions in total from 19 different patients were analyzed (mean = 6.15 lesions per patient). SUVMEAN, TLG mean, SUVMAX and TLGMAX were calculated for each lesion. SUVMEAN per patient varied from 2.69 to 15.48 while SUV50 varied from 5.45 to 48.23. ∑TLGMEAN and ∑TLGMAX ranged from 13.06 to 364.072 and 18.29 to 575.627, respectively. There was significant variation between patients and within different tumor lesions within patients. SUVPEAK for all lesions of patients ranged from 4.8 to 36.4.

Conclusions: TLG varies widely in patients with triple negative breast cancer, further studies are required to determine if this will be a useful prognostic/predictive measure in the future.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P4-01-22.

Molecular characterization of bovine group A rotavirus G3P[3] strains

During a surveillance study, four of 130 group A rotavirus strains, detected from diarrheic calves in Eastern India, exhibited G3P[3] specificities. Molecular characterization of VP7 and VP8(*) genes of one such strain [named as RUBV3 (RU: ruminant and BV: bovine)] revealed genetic relatedness to a G3P[3] simian strain, RRV, and RRV-related caprine strain GRV. Strain RUBV3 had VP6, NSP4 and NSP5 genes of bovine origin. Therefore, the present study provides evidence for multiple reassortment events involving ruminant and simian strains and, to our knowledge, is the first report of detection of bovine group A rotavirus strains with G3P[3] specificities.

Evidence for independent segregation of the VP6- and NSP4- encoding genes in porcine group A rotavirus G6P[13] strains

Molecular characterization of two porcine group A rotavirus strains (HP113 and HP140), detected from eastern India, revealed a VP7 closely related to those of human G6P[14] strains, VP4 with a borderline P[13] genotype, and VP6 related to bovine and human SGI strains rather than porcine SGI and/or SGII group A rotaviruses. Both strains had NSP4 and NSP5 of porcine origin. Therefore, to our knowledge, the present study is the first report of detection of group A rotavirus strains with G6P[13] genotype specificities and provides evidence for independent segregation of the VP6- and NSP4-encoding genes in porcine group A rotaviruses.

Changing pattern of human group A rotaviruses: Emergence of G12 as an important pathogen among children in eastern India

BACKGROUND

Rotavirus genotypes, G1-G4 and G9 are associated with childhood diarrhoea throughout the world. In our previous study, we detected G1, G2, G4 and three G12 strains from Kolkata, India.

OBJECTIVES

To study the prevalence of G- and P-genotypes of rotaviruses associated with dehydrating diarrhoea in children admitted to two leading hospitals in eastern India.

STUDY DESIGN

An active surveillance was conducted for elucidation of rotavirus infection in two leading hospitals in Kolkata, West Bengal and Berhampur (GM), Orissa, India, separated by 603km from January 2003 to April 2005. The rotaviruses were detected by RNA electrophoresis in polyacrylamide gels. G- and P-typing of the positive samples were accomplished by amplifying VP7 and VP4 genes by RT-PCR and genotyped by seminested multiplex PCR methods. Sequencing, sequence analysis and phylogenetic analysis of VP7 genes of G12 strains were carried out to understand the variations between the strains isolated from different parts of the world.

RESULTS

The genotypic distribution varied remarkably from our earlier study period (1998-2001) with G1 (53.8%) being the most predominant strain followed by G2 (22.5%), G12 (17.1%), G9 (2.1%) and not a single G3 or G4 isolate was detected separately. 35.2% samples exhibited mixed P-types followed by P[4] (31.7%), P[8] (21.8%) and P[6] (9.8%). The phylogenetic analysis of G12 strains revealed that the G12 strains detected from different parts of the world clustered into three different lineages. Though VP7 sequences of G12 strains isolated from Kolkata and Berhampur are conserved, their P-types were different.

CONCLUSION

During this study period we reported emergence of G12 strains as an important pathogen among children in eastern India, thus necessitating its inclusion in future polyvalent vaccine to control rotavirus diarrhoea.

Molecular characterization of a porcine Group A rotavirus strain with G12 genotype specificity

A porcine Group A rotavirus strain (RU172) was detected and molecularly characterized during a surveillance study conducted for rotavirus infection in a pig farm located in a suburban area of Kolkata City, India. The G12 genotype specificity of RU172 was revealed by PCR-based genotyping assays following addition of a G12 type-specific primer (designed in our laboratory to pick up G12 isolates from field samples) and was confirmed by sequence analysis of the VP7-encoding gene. The RU172 strain exhibited maximum VP7 identities of 93.6% to 94.5% with human G12 strains at the deduced amino acid level. In spite of its G12 genotype nature, RU172 appeared to be distinct from human G12 rotaviruses and, on phylogenetic analysis, formed a separate lineage with human G12 strains. Among the other gene segments analyzed, RU172 belonged to NSP4 genotype B, had a NSP5 and VP6 of porcine origin, and shared maximum VP4 identities with porcine P[7] rotaviruses (94.3%-95.4% at the deduced amino acid level). Therefore, to the best of our knowledge, this is the first report of detection of an animal rotavirus strain with G12 genotype specificity. Detection of strains like RU172 provides vital insights into the genomic diversity of Group A rotaviruses of man and animals.

Sequencing and sequence analysis of VP7 and NSP5 genes reveal emergence of a new genotype of bovine group B rotaviruses in India

Three bovine group B rotavirus strains were detected from diarrheic calves during a surveillance study of rotaviral diarrhea in West Bengal, India. The sequence analysis of VP7 and NSP5 genes of these strains demonstrates a high degree of sequence variation from other group B rotavirus strains, indicating the emergence of a new genotype.

Molecular characterization of a human rotavirus reveals porcine characteristics in most of the genes including VP6 and NSP4

Long electropherotype with Subgroup I specificity is a common feature of animal rotaviruses. In an epidemic of infantile gastroenteritis in Manipur, India, long but SG I strains predominated in the outbreak in the year 1987-88. One such strain isolated from that region, following the outbreak had G9P [19] specificity. As this is a rare combination, the gene sequences encoding VP4, VP6, VP7, NSP1, NSP2, NSP3, NSP4 and NSP5 of this strain were analyzed. All these genes except VP7 were closely related to porcine rotaviruses (95-99% identity at amino acid level) and clustered with the porcine strains in phylogenetic analysis. In addition, it had subgroup I nature and belonged to NSP4 genotype B which is characteristic of animal rotaviruses. This is the first report of a rotavirus with VP6 and NSP4, two crucial proteins thought to be involved in host range restriction and pathogenicity, were of porcine origin and caused diarrhoea in a human host. Among the genes of this strain sequenced so far, only VP7 had highest identity to human strains at amino acid level. This study suggests reassortment may be occurring between human and other animal strains and some of the reassortant viruses may be virulent to humans.

Emergence of novel human group A rotavirus G12 strains in India

Three rare human G12 strains were detected from diarrheic clinical samples of children (<8 months of age) in Calcutta during a routine surveillance study of rotaviral diarrhea in India. The VP7 genes of G12 strains and their products showed maximum homology (97 to 99% at the nucleotide level and 98% at the amino acid level, respectively) with those of two recently reported G12 strains (from the United States and Thailand) but lesser homology with those of prototype G12 strain L26.

Genomic diversity of group A rotavirus strains infecting humans in eastern India

Between 1998 and 2000, a total of 266 samples were found positive for group A rotaviruses by RNA electrophoresis. Samples were collected from patients admitted to two leading hospitals in Calcutta. Serotyping could be done only with 22% of the positive samples, leaving 78% untypeable. The G (VP7 genotypes) and P (VP4 genotypes) types were determined for 159 samples by reverse transcription and multiplex PCR. The predominant genotype was G1P[8] (20%), followed by G2P[4] (15%) and G4P[8] (6%). A number of uncommon genotypes, G1P[4] (4%), G2P[8] (2.5%), G2P[6] (0.6%), G4P[4] (2.5%), and G4P[6] (1.25%), were also detected during this study period. Twenty two percent of specimens showed mixed infections, 38 (24%) of the total samples remained untypeable for either VP7 or VP4, while only 4 (2.5%) of the samples were untypeable for both genes. Eleven specimens collected from Manipur were also genotyped and revealed a very high degree of genomic reassortment.