Gut microbiota shifts favorably with delivery of handwashing with soap and water treatment intervention in a prospective cohort (CHoBI7 trial)

BACKGROUND

Cholera can result in the expulsion of important microbiota from the gut and result in death if left untreated. The disease transmits mainly via drinking water carrying Vibrio cholerae; and household contacts (HHC) of cholera patients are at elevated risk during the first week of infection. The gut microbiota profiles of HHC-children of cholera patients at Dhaka city slums were investigated before (day 0) and after (day 8) delivery of chlorinated water as part of the major study 'CHoBI7 trial (cholera-hospital-based intervention for 7 days)'.

RESULT

Results of sequencing and analysis of bacterial community DNA revealed the predominance of two bacterial phyla: Bacteroidetes and Firmicutes at day 0 with a relative abundance of 62 ± 6 (mean ± SEM%) and 32 ± 7, respectively. The pattern reversed at day 8 with a decreased relative abundance of Bacteroidetes (39 ± 12; p = 0.034) and an increased abundance of Firmicutes (49 ± 12; p = 0.057). Of 65 bacterial families confirmed at day 0, six belonging to Proteobacteria including Vibrionaceae disappeared at day 8. Interestingly, the relative abundance of four Firmicutes families-Lachnospiraceae, Bifidobacteriaceae, Clostridiaceae, and Ruminococcaceae was increased in all five study children at day 8.

CONCLUSION

The observed exclusion of pathogenic Proteobacteria and enhancement of beneficial Firmicutes in the gut of children delivered with chlorinated water as part of WASH intervention reflect a great promise of the CHoBI7 program in preventing cholera and improving child health.

PSMA2 knockdown impacts expression of proteins involved in immune and cellular stress responses in human lung cells

Proteasome subunit alpha type-2 (PSMA2) is a critical component of the 20S proteasome, which is the core particle of the 26S proteasome complex and is involved in cellular protein quality control by recognizing and recycling defective proteins. PSMA2 expression dysregulation has been detected in different human diseases and viral infections. No study yet has reported PSMA2 knockdown (KD) effects on the cellular proteome.

METHODS

We used SOMAScan, an aptamer-based multiplexed technique, to measure >1300 human proteins to determine the impact of PSMA2 KD on A549 human lung epithelial cells.

RESULTS

PSMA2 KD resulted in significant dysregulation of 52 cellular proteins involved in different bio-functions, including cellular movement and development, cell death and survival, and cancer. The immune system and signal transduction were the most affected cellular functions. PSMA2 KD caused dysregulation of several signaling pathways involved in immune response, cytokine signaling, organismal growth and development, cellular stress and injury (including autophagy and unfolded protein response), and cancer responses.

CONCLUSIONS

In summary, this study helps us better understand the importance of PSMA2 in different cellular functions, signaling pathways, and human diseases.

Phytochemical management of root knot nematode (Meloidogyne incognita) kofoid and white chitwood by Artemisia spp. in tomato (Lycopersicon esculentum L.)

In vitro and screen house experiments were conducted to investigate the effectiveness of thirteen phytochemicals from Artemisia elegantissimia and A. incisa on root knot nematode, Meloidogyne incognita in tomato (Lycopersicon esculentum L.) cv. Rio Grande. A positive control (Carbofuran) and negative control (H2O) were also used for comparison. Effectiveness of phytochemicals against juveniles (J2s) mortality and egg hatch inhibition were evaluated after 24, 48 and 72 hours of incubation at three concentrations viz; 0.1, 0.2 and 0.3 mg/mL in vitro conditions. Amongst thirteen phytochemicals, Isoscopletin (Coumarin), Carbofuran and Apigenin (Flavonoid) showed the highest mortality and egg hatch inhibition of M. incognita at all intervals. Inhibition of eggs and J2s mortality were the greatest (90.0%) and (96.0%) at 0.3 mg/mL concentration. Application of phytochemicals caused reduction in number of galls, galling index, and egg masses on tomato plant and enhanced plant growth parameters under screen house conditions. Gall numbers (1.50), galling index (1.00), number of juveniles (4.83) and egg masses (4.00) were greatly reduced and plant growth parameters such as; plant height (28.48 cm), fresh (72.13 g) and dry shoot weights (35.99 g), and root fresh (6.58 g) and dry weights (1.43 g) were increased significantly by using Isoscopletin. In structure activity relationship, juveniles of M. incognita, exhibited variations in their shape and postures upon death when exposed to different concentrations of phytochemicals of Artemisia spp. The present study suggests that Artemisia based phytochemicals possess strong nematicidal effects and can be used effectively in an integrated disease management program against root knot nematodes.

Effects of a Water, Sanitation and Hygiene Mobile Health Program on Diarrhea and Child Growth in Bangladesh: A Cluster-Randomized Controlled Trial of the CHoBI7 Mobile Health Program

Background

The Cholera Hospital-Based Intervention for 7 Days (CHoBI7) mobile health (mHealth) program was a cluster-randomized controlled trial of diarrhea patient households conducted in Dhaka, Bangladesh.

Methods

Patients were block-randomized to 3 arms: standard message on oral rehydration solution use; health facility delivery of CHoBI7 plus mHealth (no home visits); and health facility delivery of CHoBI7 plus 2 home visits and mHealth. The primary outcome was reported diarrhea in the past 2 weeks collected monthly for 12 months. The secondary outcomes were stunting, underweight, and wasting at a 12-month follow-up. Analysis was intention-to-treat.

Results

Between 4 December 2016 and 26 April 2018, 2626 participants in 769 households were randomly allocated to 3 arms: 849 participants to the standard message arm, 886 to mHealth with no home visits arm, and 891 to the mHealth with 2 home visits. Children <5 years had significantly lower 12-month diarrhea prevalence in both the mHealth with 2 home visits arm (prevalence ratio [PR]: 0.73 [95% confidence interval {CI}, .61–.87]) and the mHealth with no home visits arm (PR: 0.82 [95% CI, .69–.97]). Children <2 years were significantly less likely to be stunted in both the mHealth with 2 home visits arm (33% vs 45%; odds ratio [OR]: 0.55 [95% CI, .31–.97]) and the mHealth with no home visits arm (32% vs 45%; OR: 0.54 [95% CI, .31–.96]) compared with children in the standard message arm.

Conclusions

The CHoBI7 mHealth program lowered pediatric diarrhea and stunting among diarrhea patient households.

Clinical Trials Registration

NCT04008134.

Process evaluation for the delivery of a water, sanitation and hygiene mobile health program: findings from the randomised controlled trial of the CHoBI7 mobile health program

OBJECTIVE

The Cholera-Hospital-Based Intervention for 7-days (CHoBI7) mobile health (mHealth) program delivers mobile messages to diarrhoea patient households promoting water treatment and handwashing with soap. The randomised controlled trial (RCT) of the CHoBI7 mHealth program demonstrated this intervention was effective in significantly reducing diarrhoea and stunting amoung young children. The objective of this study was to assess the implementation of the CHoBI7 mHealth program in delivering mHealth messages during this RCT.

METHODS

517 diarrhoea patient households with 1777 participants received weekly text, voice and interactive voice response (IVR) messages from the CHoBI7 mHealth program over the 12-month program period. The program process evaluation indicators were the following: the percentage of CHoBI7 mHealth messages received and fully listened to by program households (program fidelity and dose), and household members reporting receiving and sharing an mHealth message from the program in the past two weeks (program reach).

RESULTS

Ninety two percent of text messages were received by program households. Eighty three percent of voice and 86% of IVR messages sent were fully listened to by at least one household member. Eighty one percent of IVR quiz responses from households were answered correctly. Program households reported receiving a CHoBI7 mHealth message in the past two weeks at 79% of monthly household visits during the 12-month program. Seventy seven percent of participants reported sharing a program message with a spouse, 55% with a neighbour and 49% with a child during the program period.

CONCLUSION

There was high fidelity, dose and reach of mobile messages delivered for the CHoBI7 mHealth program. This study presents an approach for process evaluation that can be implemented to evaluate future mHealth programs.

Serum-reduced media impacts on cell viability and protein expression in human lung epithelial cells

Serum starvation is a widely used condition in molecular biology experiments. Opti‐MEM is a serum‐reduced media used during transfection of genetic molecules into mammalian cells. However, the impact of such media on cell viability and protein synthesis is unknown. A549 human lung epithelial cell viability and morphology were adversely affected by growing in Opti‐MEM. The cellular protein levels of chloride intracellular channel protein 1, proteasome subunit alpha Type 2, and heat shock 70 kDa protein 5 were dysregulated in A549 cells after growing in serum‐reduced media. Small interfering RNA transfection was done in Dulbecco's modified Eagle's medium (DMEM) with 10% fetal bovine serum, and knockdown efficacy was determined compared with Opti‐MEM. Similar amounts of knockdown of the target proteins were achieved in DMEM, and cell viability was higher compared with Opti‐MEM after transfection. Careful consideration of the impact of Opti‐MEM media during the culture or transfection is important for experimental design and results interpretation.

Existence of a novel qepA variant in quinolone resistant Escherichia coli from aquatic habitats of Bangladesh

Of 19 environmental Escherichia coli (n = 12) and Klebsiella pneumoniae (n = 7) tested for quinolone resistance-related genes qnrA, qnrB, qnrC, qnrS and qepA, four each of E. coli and K. pneumoniae possessed qnrS, and another E. coli isolate possessed a new variant of qepA. This is the first detection of qepA in environmentally dwelling bacteria in Bangladesh.

Risk Factors for Household Transmission of Vibrio cholerae in Dhaka, Bangladesh (CHoBI7 Trial)

AbstractHousehold contacts of cholera patients are at a 100 times higher risk of a Vibrio cholerae infection than the general population. To examine risk factors for V. cholerae infections and investigate intervention strategies among this population, we followed household contacts of cholera patients for the 1-week high-risk period after the index patient obtained care. This study was nested within a randomized controlled trial of the Cholera-Hospital-Based-Intervention-for-7-days (CHoBI7), a handwashing with soap and water treatment intervention in Dhaka, Bangladesh. Rectal swab results were available from 320 household contacts of cholera patients at five time points over a 1-week period. Fecal and water samples were analyzed for V. cholerae by bacterial culture. All analyses were stratified by study arm. Within the intervention arm, stored household drinking water with a median free chlorine concentration below 0.5 mg/L was associated with a three times higher odds of a cholera infection (odds ratio [OR]: 3.0; 95% confidence interval [CI]: 1.32, 6.63). In the control arm, having V. cholerae in stored water was associated with a significantly higher odds of a symptomatic cholera infection (OR: 8.66; 95% CI: 2.11, 35.48). No association was found between observed handwashing with soap at food and stool-related events and V. cholerae infections. Stored household drinking water with detectable V. cholerae and chlorine concentrations below the World Health Organization guideline were found to be important risk factors for cholera infection among household contacts of cholera patients. These findings emphasize the need for water treatment interventions targeting this high risk population.

Prevalence and Penetrance of BRCA1 and BRCA2 Germline Mutations in Colombian Breast Cancer Patients

Pathogenic BRCA1/2 germline mutations confer high risks of breast and ovarian cancer to women of European ancestry. Characterization of BRCA1/2 mutations in other ethnic groups is also medically important. We comprehensively screened 68 Colombian breast/ovarian cancer families for small-range mutations, 221 families for large-genomic rearrangements, and 1,022 unselected breast cancer cases for Colombian founder mutations in BRCA1/2. The risk of cancer among relatives of mutation carriers and the mutation penetrance were estimated by survival analysis. Identified BRCA2 mutations included 6310delGA and the recurrent 1991del4 mutations. A novel large BRCA2 deletion was found in 0.9% of the screened families. Among unselected breast cancer cases, 3.3% tested positive for BRCA1/3450del4, 2.2% for BRCA1/A1708E, 1.1% for BRCA2/3034del4, and 0.4% for BRCA2/1991del4. Female relatives of carriers of BRCA1/2 founder mutations showed a 5.90 times higher risk of breast cancer, when the woman herself carried a BRCA1 mutation compared to a non-carrier (95% CI 2.01–17.3). The estimated cumulative risk of breast cancer by age 70 years for BRCA1 mutations carriers was 14% (95% CI 5–38) compared to 3% for the general Colombian population (relative risk of breast cancer 4.05). Together with known founder mutations, reported novel variants may ease a cost-effective BRCA1/2 screening in women with Colombian ancestry.

Chlorination of Household Drinking Water Among Cholera Patients' Households to Prevent Transmission of Toxigenic Vibrio cholerae in Dhaka, Bangladesh: CHoBI7 Trial

Household members of cholera patients are at a 100 times higher risk of cholera infections than the general population because of shared contaminated drinking water sources and secondary transmission through poor household hygiene practices. In this study, we investigated the bactericidal concentration of free chlorine required to inactivate Vibrio cholerae in household drinking water in Dhaka, Bangladesh. In laboratory experiments, we found that the concentrations of free chlorine required to inactivate 105 colony-forming units (CFU)/mL of V. cholerae serogroups O1 and O139 were 0.1 mg/L and 0.2 mg/L, respectively. The concentration of free chlorine generated by a single chlorine tablet (sodium dichloroisocyanurate [33 mg]) after a 30-minute reaction time in a 10-L sealed vessel containing Dhaka city municipal supply water was 1.8 mg/L; and the concentration declined to 0.26 mg/L after 24 hours. In field measurements, water collected from 165 households enrolled in a randomized controlled trial (RCT) of a chlorine and handwashing with soap intervention (Cholera-Hospital-Based-Intervention-for-7-Days [CHoBI7]), we observed significantly higher free chlorine concentrations in the 82 intervention arm households (mean = 1.12 mg/L, standard deviation [SD] = 0.52, range = 0.07-2.6 mg/L) compared with the 83 control households (0.017 mg/L, SD = 0.01, range = 0-0.06 mg/L) (P < 0.001) during spot check visits. These findings suggest that point-of-use chlorine tablets present an effective approach to inactivate V. cholerae from drinking water in households of cholera patients in Dhaka city. This result is consistent with the findings from the RCT of CHoBI7 which found that this intervention led to a significant reduction in symptomatic cholera infections among household members of cholera patients and no stored drinking water samples with detectable V. cholerae.

Rapid dipstick detection of Vibrio cholerae in household stored and municipal water in Dhaka, Bangladesh: CHoBI7 trial

OBJECTIVE

In urban Dhaka, Bangladesh, 30% of source water samples collected from the households of patients with cholera had detectable Vibrio cholerae. These findings indicate an urgent need for a public health intervention for this population. The Crystal VC^® dipstick test is a rapid method for detecting V. cholerae in stool and water. However, to date no study has investigated the use of the rapid dipstick test for household surveillance of stored drinking water.

METHODS

The efficacy of the Crystal VC^® dipstick test for detecting V. cholerae in the Dhaka city municipal water supply and stored household drinking water sources after enrichment for 18 h in alkaline peptone water (APW) was compared to bacterial culture as the gold standard.

RESULTS

A total of 1648 water samples (824 stored household drinking water samples and 824 municipal water supply samples) were collected from households of patients with cholera. The overall specificity and sensitivity of the dipstick test compared to bacterial culture was 99.6% (95% confidence interval (CI): 99.2%, 99.9%) and 65.6% (95% CI: 55.2%, 75%), respectively. The specificities for stored household drinking water and Dhaka city municipal supply water compared to bacterial culture were 99.8% (95% CI: 99.1%, 100%) and 99.5% (95% CI: 98.6%, 99.9%), respectively (P = 0.138), and the sensitivities were 66.7% (95% CI: 43.0%, 85.4%) and 65.3% (95% CI: 53.5%, 76.0%), respectively (P = 0.891).

CONCLUSION

The Crystal VC^® dipstick is a promising screening tool for cholera outbreak surveillance in resource-limited settings where elimination of false-positive results is critical. The lower than expected sensitivity should be further investigated in future studies.

Transmission of Infectious Vibrio cholerae through Drinking Water among the Household Contacts of Cholera Patients (CHoBI7 Trial)

Recurrent cholera causes significant morbidity and mortality among the growing population of Dhaka, the capital city of Bangladesh. Previous studies have demonstrated that household contacts of cholera patients are at >100 times higher risk of cholera during the week after the presentation of the index patient. Our prospective study investigated the mode of transmission of Vibrio cholerae, the cause of cholera, in the households of cholera patients in Dhaka city. Out of the total 420 rectal swab samples analyzed from 84 household contacts and 330 water samples collected from 33 households, V. cholerae was isolated from 20%(17/84) of household contacts, 18%(6/33) of stored drinking water, and 27%(9/33) of source water samples. Phenotypic and molecular analyses results confirmed the V. cholerae isolates to be toxigenic and belonging to serogroup O1 biotype El Tor (ET) possessing cholera toxin of classical biotype (altered ET). Phylogenetic analysis by pulsed-field gel electrophoresis (PFGE) showed the V. cholerae isolates to be clonally linked, as >95% similarity was confirmed by sub-clustering patterns in the PFGE (NotI)-based dendrogram. Mapping results showed cholera patients to be widely distributed across 25 police stations. The data suggesting the transmission of infectious V. cholerae within the household contacts of cholera patients through drinking water underscores the need for safe water to prevent spread of cholera and related deaths in Dhaka city.

Promotion of Cholera Awareness Among Households of Cholera Patients: A Randomized Controlled Trial of the Cholera-Hospital-Based-Intervention-for-7 Days (CHoBI7) Intervention

Previous studies have demonstrated that household contacts of cholera patients are highly susceptible to cholera infections for a 7-day period after the presentation of the index patient in the hospital. However, there is no standard of care to prevent cholera transmission in this high-risk population. Furthermore, there is limited information available on awareness of cholera transmission and prevention among cholera patients and their household contacts. To initiate a standard of care for this high-risk population, we developed the Cholera-Hospital-Based-Intervention-for-7-Days (CHoBI7), which delivers a handwashing with soap and water treatment intervention to household contacts during the time they spend with the admitted cholera patient in the hospital and reinforces these messages through home visits. To test CHoBI7, we conducted a randomized controlled trial among 302 intervention cholera patient household members and 302 control cholera patient household members in Dhaka, Bangladesh. In this study, we evaluated the effectiveness of the CHoBI7 intervention in increasing awareness of cholera transmission and prevention, and the key times for handwashing with soap. We observed a significant increase in cholera knowledge score in the intervention arm compared with the control arm at both the 1-week follow-up {score coefficient = 2.34 (95% confidence interval [CI] = 1.96, 2.71)} and 6 to 12-month follow-up period (score coefficient = 1.59 [95% CI = 1.05, 2.13]). This 1-week hospital- and home-based intervention led to a significant increase in knowledge of cholera transmission and prevention which was sustained 6 to 12 months post-intervention. These findings suggest that the CHoBI7 intervention presents a promising approach to increase cholera awareness among this high-risk population.

Observed Handwashing with Soap Practices Among Cholera Patients and Accompanying Household Members in a Hospital Setting (CHoBI7 Trial)

Household members of cholera patients are at a 100 times higher risk of cholera than the general population. Despite this risk, there are only a handful of studies that have investigated the handwashing practices among hospitalized diarrhea patients and their accompanying household members. To investigate handwashing practices in a hospital setting among this high-risk population, 444 hours of structured observation was conducted in a hospital in Dhaka, Bangladesh, among 148 cholera patients and their household members. Handwashing with soap practices were observed at the following key events: after toileting, after cleaning the anus of a child, after removing child feces, during food preparation, before eating, and before feeding. Spot-checks were also conducted to observe the presence of soap at bathroom areas. Overall, 4% (4/103) of key events involved handwashing with soap among cholera patients and household members during the structured observation period. This was 3% (1/37) among cholera patients and 5% (3/66) for household members. For toileting events, observed handwashing with soap was 7% (3/46) overall, 7% (1/14) for cholera patients, and 6% (2/32) for household members. For food-related events, overall observed handwashing with soap was 2% (2/93 overall), and 0% (0/34) and 3% (2/59) for cholera patients and household members, respectively. Soap was observed at only 7% (4/55) of handwashing stations used by patients and household members during spot-checks. Observed handwashing with soap at key times among patients and accompanying household members was very low. These findings highlight the urgent need for interventions to target this high-risk population.

Comparison of inferred relatedness based on multilocus variable-number tandem-repeat analysis and whole genome sequencing of Vibrio cholerae O1

Vibrio cholerae causes cholera, a severe diarrheal disease. Understanding the local genetic diversity and transmission of V. cholerae will improve our ability to control cholera. Vibrio cholerae isolates clustered in genetically related groups (clonal complexes, CC) by multilocus variable tandem-repeat analysis (MLVA) were compared by whole genome sequencing (WGS). Isolates in CC1 had been isolated from two geographical locations. Isolates in a second genetically distinct group, CC2, were isolated only at one location. Using WGS, CC1 isolates from both locations revealed, on average, 43.8 nucleotide differences, while those strains comprising CC2 averaged 19.7 differences. Strains from both MLVA-CCs had an average difference of 106.6. Thus, isolates comprising CC1 were more closely related (P < 10(-6)) to each other than to isolates in CC2. Within a MLVA-CC, after removing all paralogs, alternative alleles were found in all possible combinations on separate chromosomes indicative of recombination within the core genome. Including recombination did not affect the distinctiveness of the MLVA-CCs when measured by WGS. We found that WGS generally reflected the same genetic relatedness of isolates as MLVA, indicating that isolates from the same MLVA-CC shared a more recent common ancestor than isolates from the same location that clustered in a distinct MLVA-CC.

The origin of endodontic Enterococcus faecalis explored by comparison of virulence factor patterns and antibiotic resistance to that of isolates from stool samples, blood cultures and food

AIM

To elucidate the origin of Enterococcus faecalis isolated from secondary root canal infections and the possibility for a foodborne transmission by comparing them to strains recovered from food, blood and stool regarding putative virulence factors and antibiotic susceptibility profiles, where strains from common origin were hypothesized to harbour similar characteristics.

METHODOLOGY

A total of 108 E. faecalis strains recovered in the county of Stockholm, Sweden, were screened using PCR for putative virulence factors esp, cylA, gelE/gelatinase-negative phenotype (ef1841/fsrC), efaA, ace and asa1. The minimum inhibitory concentration (MIC) for ampicillin, piperacillin-tazobactam, imipenem, gentamicin, vancomycin, ciprofloxacin and linezolid was determined using the agar dilution method.

RESULTS

Next to strains from blood, the food isolates presented the highest average number of virulence determinants and were frequently enriched with asa1 coding for aggregation substance. None of the endodontic strains carried cylA, and the gelatinase-negative phenotype caused by a deletion dominated the group. Altogether, the most prevalent genes were gelE, efaA and ace, and a combination of them was equally present in approximately 80% of the strains from food, stool and root canals in comparison with 43.3% of the blood isolates. High-level resistance to ciprofloxacin and gentamicin was observed in 30% of the blood isolates, whereas the isolates from other origins, with single exceptions, were susceptible to all tested antibiotics.

CONCLUSIONS

Evidence for a foodborne transmission, explaining the high reported prevalence of E. faecalis in root filled teeth, could not be determined based on the similarities in virulence factor patterns and antibiotic susceptibility. The only linkage between isolates from food and root canals consisted of a shared common combination of the genes gelE, efaA and ace. The high occurrence of putative virulence traits in food isolates questions the safety of E. faecalis in food products.

Cholera outbreaks (2012) in three districts of Nepal reveal clonal transmission of multi-drug resistant Vibrio cholerae O1

Background

Although endemic cholera causes significant morbidity and mortality each year in Nepal, lack of information about the causal bacterium often hinders cholera intervention and prevention. In 2012, diarrheal outbreaks affected three districts of Nepal with confirmed cases of mortality. This study was designed to understand the drug response patterns, source, and transmission of Vibrio cholerae associated with 2012 cholera outbreaks in Nepal.

Methods

V. cholerae (n = 28) isolated from 2012 diarrhea outbreaks {n = 22; Kathmandu (n = 12), Doti (n = 9), Bajhang (n = 1)}, and surface water (n = 6; Kathmandu) were tested for antimicrobial response. Virulence properties and DNA fingerprinting of the strains were determined by multi-locus genetic screening employing polymerase chain reaction, DNA sequencing, and pulsed-field gel electrophoresis (PFGE).

Results

All V. cholerae strains isolated from patients and surface water were confirmed to be toxigenic, belonging to serogroup O1, Ogawa serotype, biotype El Tor, and possessed classical biotype cholera toxin (CTX). Double-mismatch amplification mutation assay (DMAMA)-PCR revealed the V. cholerae strains to possess the B-7 allele of ctx subunit B. DNA sequencing of tcpA revealed a point mutation at amino acid position 64 (N → S) while the ctxAB promoter revealed four copies of the tandem heptamer repeat sequence 5'-TTTTGAT-3'. V. cholerae possessed all the ORFs of the Vibrio seventh pandemic island (VSP)-I but lacked the ORFs 498–511 of VSP-II. All strains were multidrug resistant with resistance to trimethoprim-sulfamethoxazole (SXT), nalidixic acid (NA), and streptomycin (S); all carried the SXT genetic element. DNA sequencing and deduced amino acid sequence of gyrA and parC of the NA^R strains (n = 4) revealed point mutations at amino acid positions 83 (S → I), and 85 (S → L), respectively. Similar PFGE (NotI) pattern revealed the Nepalese V. cholerae to be clonal, and related closely with V. cholerae associated with cholera in Bangladesh and Haiti.

Conclusions

In 2012, diarrhea outbreaks in three districts of Nepal were due to transmission of multidrug resistant V. cholerae El Tor possessing cholera toxin (ctx) B-7 allele, which is clonal and related closely with V. cholerae associated with cholera in Bangladesh and Haiti.

Evaluation of enrichment method for the detection of Vibrio cholerae O1 using a rapid dipstick test in Bangladesh

BACKGROUND

To evaluate the specificity of the Crystal VC dipstick test for detecting cholera.

METHODS

We compared direct testing using the Crystal VC dipstick test and testing after enrichment for 6 h in alkaline peptone water (APW) to bacterial culture as the gold standard. Samples positive by dipstick but negative by culture were also tested using PCR.

RESULTS

Stool was collected from 125 patients. The overall specificities of the direct testing and testing after 6-h enrichment in APW compared to bacterial culture were 91.8% and 98.4% (P = 0.125), respectively, and the sensitivities were 65.6% and 75.0% (P = 0.07), respectively.

CONCLUSION

The increase in the sensitivity of the Crystal VC kit with the use of the 6-h enrichment step in APW compared to direct testing was marginally significant. The Crystal VC dipstick had a much higher specificity than previously reported (91-98%). Therefore, this method might be a promising screening tool for cholera outbreak surveillance in resource-limited settings where elimination of false-positive results is critical.

Spectrum of K ras mutations in Pakistani colorectal cancer patients

The incidence of colorectal cancer (CRC) is increasing daily worldwide. Although different aspects of CRC have been studied in other parts of the world, relatively little or almost no information is available in Pakistan about different aspects of this disease at the molecular level. The present study was aimed at determining the frequency and prevalence of K ras gene mutations in Pakistani CRC patients. Tissue and blood samples of 150 CRC patients (64% male and 36% female) were used for PCR amplification of K ras and detection of mutations by denaturing gradient gel electrophoresis, restriction fragment length polymorphism analysis, and nucleotide sequencing. The K ras mutation frequency was found to be 13%, and the most prevalent mutations were found at codons 12 and 13. A novel mutation was also found at codon 31. The dominant mutation observed was a G to A transition. Female patients were more susceptible to K ras mutations, and these mutations were predominant in patients with a nonmetastatic stage of CRC. No significant differences in the prevalence of K ras mutations were observed for patient age, gender, or tumor type. It can be inferred from this study that Pakistani CRC patients have a lower frequency of K ras mutations compared to those observed in other parts of the world, and that K ras mutations seemed to be significantly associated with female patients.

Effect of mefenamic acid on bowel transit time in healthy adult volunteers

The effect of mefenamic acid on bowel transit time was investigated. Seven healthy adult male subjects of age 39 +/- 2.4 years (mean +/- S.E.M.) received placebo or mefenamic acid (500 mg t.d.s) orally in randomized order for five days, with a 7-day washout between studies. On the third morning after starting the drug they had a meal containing Redi-Brek and baked beans with radio-opaque markers. Small bowel transit time was measured using breath hydrogen, and whole gut transit time was measured using radio-opaque markers. The small bowel transit times were 160 min (median) with placebo and 50 min with mefenamic acid (P less than 0.05). The percentages of appearance of marker in stool within 24 h were 24.9 +/- 11.8 (mean +/- S.E.M.) with placebo and 48.9 +/- 11.7 with mefenamic acid (P less than 0.05). The times of appearance of twenty-fifth marker in stool were 41.0 +/- 4.4 h with placebo and 26.9 +/- 3.2 h with mefenamic acid (P less than 0.05). The total weights of faeces in 72 h were 500.9 +/- 96.2 g with placebo and 657.1 +/- 118.8 g with mefenamic acid (P less than 0.05). Mefenamic acid in therapeutic doses (500 mg t.d.s.) accelerated bowel transit time in healthy subjects.

Effect of intravenous atropine on gastric emptying, paracetamol absorption, salivary flow and heart rate in young and fit elderly volunteers

1. The effects of atropine on gastric emptying, paracetamol absorption, salivary flow and heart rate were examined in young and elderly subjects. 2. Seven healthy young male subjects of age 23 +/- 1.3 years (mean +/- s.e. mean) and seven fit elderly subjects of age 70 +/- 1.6 years received placebo (P), 300 micrograms atropine (A300) or 600 micrograms atropine (A600) in randomized order at weekly intervals. After 10 min they ingested a 500 ml orange drink containing 1 g paracetamol. Gastric emptying was measured by ultrasound, blood samples were taken to measure plasma paracetamol concentration by h.p.l.c., salivary flow was measured by dental cotton wool cylinder technique and pulse rate was recorded. 3. In young subjects, the gastric 5 min volumes were 260.1 +/- 17.9 ml (s.e. mean) with P, 310.6 +/- 10.5 ml with A300 and 317.9 +/- 8.9 ml with A600. In elderly subjects, the gastric 5 min volumes were 166.7 +/- 10.1 ml with P, 252.6 +/- 13.7 ml with A300 and 266.0 +/- 14.8 ml with A600. Thus the early adaptive phase of gastric emptying was more rapid in the elderly than the young with all treatments (P less than 0.05). The gastric emptying half-lives were 18.8 +/- 2.5 min with P, 30.0 +/- 2.7 min with A300 and 34.5 +/- 3.3 min with A600 in young subjects (P less than 0.01). In elderly subjects, the gastric emptying half-lives were 16.1 +/- 2.5 min with P, 23.7 +/- 2.4 min with A300 and 30.0 +/- 2.9 min with A600 (P less than 0.01). Thus atropine intravenously in therapeutic dose (300 and 600 micrograms) delayed gastric emptying in both young and elderly subjects. The inhibitory effect of atropine on the early adaptive phase of gastric emptying appeared to be greater in the elderly. The maximum plasma concentration (Cmax) of paracetamol was greater in the elderly than young with all treatments (P less than 0.05). There was a close relationship between the early adaptive phase of gastric emptying and paracetamol absorption (P less than 0.05). Atropine reduced salivary flow and increased resting heart rate in both young and old subjects. The effect of atropine on salivary flow was greater in the elderly. 4. The dose-response relationship varied in the three systems (stomach, salivary glands and heart rate) studied. Age had an effect on the magnitude of the response, but not on the slope of the dose-response curve for the two doses of atropine studied.(ABSTRACT TRUNCATED AT 400 WORDS)

The effect of pharmacological modification of gastric emptying and mouth-to-caecum transit time on the absorption of sugar probe marker molecules of intestinal permeability in normal man

The present study examined the hypothesis that altered motility of the gastrointestinal tract affects absorption of probe markers of intestinal permeability. Seven healthy subjects, aged 32-44 years, received saline, 600 micrograms atropine or 10 mg metoclopramide in randomized order at weekly intervals. After 10 min they ingested a test solution containing 5 g lactulose, 5 g mannitol and 2 g 3-O-methyl glucose in 100 ml tap water. The molarity of the solution was 542 mmol l-1 and the dose administered was 80 ml m-2 body surface area. Gastric emptying was measured by ultrasound, mouth-to-caecum transit time by breath hydrogen analysis and sugar concentrations by gas-liquid chromatography. Gastric emptying half-times (min) were [mean (95% confidence intervals)] 14.9 (11:4-18.5) after saline, 22 (18.7-25.2) after atropine and 10.3 (7.0-12.6) after metoclopramide (P less than 0.002). Transit times (min) were 68.9 (52-85.2) after saline, 143 (126-159) after atropine and 38 (21.2-54.5) after metoclopramide; P less than 0.0001. Analysis of plasma levels of mannitol and 3-O-methyl glucose showed a significant within-subject effect of drug with time (P less than 0.03). Urinary excretion of mannitol in the first 5 h after ingestion of the test solution was 1256 (974-1620) mg after saline, 1560 (1210-2013) mg after atropine and 955 (740-1232) mg after metoclopramide (P less than 0.03). There were no significant differences in lactulose and 3-O-methyl glucose urinary excretion between drug treatments.(ABSTRACT TRUNCATED AT 250 WORDS)