Study of anaemia in pregnancy and low birth weight in fluoride endemic area of Western Rajasthan: a cohort study

Background

Fluoride is a noxious element known to destroy gastrointestinal mucosa, leading to erythrocytes' destruction and causing anaemia. The birth weight of newborn babies is a significant indicator of a child's vulnerability to the risk of childhood diseases and chances of existence.

Methods

This prospective cohort study was planned to find linkages between fluorosis and the low-birth weight of newborn babies with anaemic mothers. Antenatal mothers until the 20th week of gestation were followed up till delivery in the Antenatal Clinic of a District Hospital in one of the known fluoride-endemic districts (Nagaur) and the other not-so-endemic district (Jodhpur) of Western Rajasthan.

Results

Around 19% of the newborn in Jodhpur and around 22% in Nagaur had low birth weight. Mean fluoride values in water samples were measured to be 0.57 (range from 0.0 to 2.7 PPM) in Jodhpur and 0.7 (range from 0.0 to 3.4 PPM) in Nagaur.

Conclusions

Thus, in fluoride endemic areas, other factors should be included besides iron and folic acid supplementation for improving anaemia in pregnant women. This calls for assessing the effectiveness of de-fluoridation activities along with the area's most common indigenous food practices.

National and regional prevalence of gestational diabetes mellitus in India: a systematic review and Meta-analysis

BACKGROUND

Gestational diabetes mellitus (GDM) is frequently misdiagnosed during pregnancy. There is an abundance of evidence, but little is known regarding the regional prevalence estimates of GDM in India. This systematic review and meta-analysis aims to provide valuable insights into the national and regional prevalence of GDM among pregnant women in India.

METHODS

We conducted an initial article search on PubMed, Scopus, Google Scholar, and ShodhGanga searches to identify quantitative research papers (database inception till 15th June,2022). This review included prevalence studies that estimated the occurrence of GDM across different states in India.

RESULTS

Two independent reviewers completed the screening of 2393 articles, resulting in the identification of 110 articles that met the inclusion criteria, which collectively provided 117 prevalence estimates. Using a pooled estimate calculation (with an Inverse square heterogeneity model), the pooled prevalence of GDM in pregnant women was estimated to be 13%, with a 95% confidence interval (CI) ranging from 9 to 16%.. In India, Diabetes in Pregnancy Study of India (DIPSI) was the most common diagnostic criteria used, followed by International Association of Diabetes and Pregnancy Study Groups (IADPSG) and World Health Organization (WHO) 1999. It was observed that the rural population has slightly less prevalence of GDM at 10.0% [6.0-13.0%, I2=96%] when compared to the urban population where the prevalence of GDM was 12.0% [9.0-16.0%, I2 = 99%].

CONCLUSIONS

This review emphasizes the lack of consensus in screening and diagnosing gestational diabetes mellitus (GDM), leading to varied prevalence rates across Indian states. It thoroughly examines the controversies regarding GDM screening by analyzing population characteristics, geographic variations, diagnostic criteria agreement, screening timing, fasting vs. non-fasting approaches, cost-effectiveness, and feasibility, offering valuable recommendations for policy makers. By fostering the implementation of state-wise screening programs, it can contribute to improving maternal and neonatal outcomes and promoting healthier pregnancies across the country.

Electrocardiogram Detection of Pulmonary Hypertension Using Deep Learning

BACKGROUND

Pulmonary hypertension (PH) is life-threatening, and often diagnosed late in its course. We aimed to evaluate if a deep learning approach using electrocardiogram (ECG) data alone can detect PH and clinically important subtypes. We asked: does an automated deep learning approach to ECG interpretation detect PH and its clinically important subtypes?

METHODS AND RESULTS

Adults with right heart catheterization or an echocardiogram within 90 days of an ECG at the University of California, San Francisco (2012-2019) were retrospectively identified as PH or non-PH. A deep convolutional neural network was trained on patients' 12-lead ECG voltage data. Patients were divided into training, development, and test sets in a ratio of 7:1:2. Overall, 5016 PH and 19,454 patients without PH were used in the study. The mean age at the time of ECG was 62.29 ± 17.58 years and 49.88% were female. The mean interval between ECG and right heart catheterization or echocardiogram was 3.66 and 2.23 days for patients with PH and patients without PH, respectively. In the test dataset, the model achieved an area under the receiver operating characteristic curve, sensitivity, and specificity, respectively of 0.89, 0.79, and 0.84 to detect PH; 0.91, 0.83, and 0.84 to detect precapillary PH; 0.88, 0.81, and 0.81 to detect pulmonary arterial hypertension, and 0.80, 0.73, and 0.76 to detect group 3 PH. We additionally applied the trained model on ECGs from participants in the test dataset that were obtained from up to 2 years before diagnosis of PH; the area under the receiver operating characteristic curve was 0.79 or greater.

CONCLUSIONS

A deep learning ECG algorithm can detect PH and PH subtypes around the time of diagnosis and can detect PH using ECGs that were done up to 2 years before right heart catheterization/echocardiogram diagnosis. This approach has the potential to decrease diagnostic delays in PH.

P2Y12 Inhibitors in Acute Coronary Syndromes: A Real-World, Community-Based Comparison of Ischemic and Bleeding Outcomes

Background

Randomized trials have shown superiority of the novel P2Y12 inhibitors over clopidogrel in patients with acute coronary syndrome (ACS), but clinical benefit in the community remains controversial. Our objective was to compare the safety and efficacy of clopidogrel to ticagrelor and prasugrel in patients with ACS undergoing percutaneous coronary intervention (PCI) in a real-world population.

Methods

We conducted a retrospective cohort study of patients with ACS who underwent PCI and were discharged with clopidogrel, ticagrelor, or prasugrel from 2012 to 2018 within Kaiser Permanente Northern California. We used Cox proportional hazard models with propensity-score matching to evaluate the association of the P2Y12 agent with the primary outcomes of all-cause mortality, myocardial infarction (MI), stroke, and bleeding events.

Results

The study included 15,476 patients (93.1% on clopidogrel, 3.6% on ticagrelor and 3.2% on prasugrel). Compared to the clopidogrel group, ticagrelorand prasugrel patients were younger with less comorbidities. In multivariable models with propensity-score matching, we found a lower risk of all-cause mortality in the ticagrelor vs the clopidogrel group (HR (95% CI) 0.43 (0.20-0.92)), but no differences in the other endpoints, and no difference between prasugrel and clopidogrel among any endpoints. A larger proportion of patients on ticagrelor or prasugrel switched to an alternative P2Y12 agent vs. clopidogrel (p < 0.01), and a higher level of persistence was seen among patients on clopidogrel vs. ticagrelor (p = 0.03) or prasugrel (p < 0.01).

Conclusion

Among patients with ACS who underwent PCI, we observed a lower risk of all-cause mortality in patients treated with ticagrelor vs clopidogrel, but no difference in other clinical endpoints nor any differences in endpoints between prasugrel vs. clopidogrel users. These results suggest that further study is needed to identify an optimal P2Y12 inhibitor in a real-world population.

Musculoskeletal disorders among doctors and nursing officers : an occupational hazard of overstrained healthcare delivery system in western Rajasthan, India

BACKGROUND

The present study was conducted to estimate the prevalence and distribution of MSDs in different anatomical regions among Doctors and NO and to determine their ergonomic risk factors and predictors.

METHODS

This cross-sectional study was conducted in an apex institution in Western India. The socio-demographic information, medical and occupational history, and other personal and work-related attributes were captured using a semi-structured questionnaire, which was developed and finalized by piloting on 32 participants (who were not part of the study). Nordic Musculoskeletal and International Physical Activity Questionnaires were used to assess MSDs and Physical activity. Data were analyzed using SPSS v.23. Prevalence of Musculoskeletal Symptoms (M.S.), Multisite Musculoskeletal Symptoms (MMS), and Widespread Musculoskeletal Symptoms (WMS) were calculated. A comparison was made to estimate the burden and distribution of MSD among Doctors and Nursing officers. Logistic regression was applied to identify the predictors of MSDs and pinpoint the risk factors associated with MSDs.

RESULTS

A total of 310 participants, of which 38.7% were doctors, and 61.3% were Nursing Officers (NOs) were included in the study. The mean age of the respondents was 31.63 ± 4.9 years. Almost 73% (95%CI: 67.9-78.1) of participants had MSD in the last 12 months, with approximately 41.6% (95%CI: 36.1-47.3) suffering from MSDs in the previous seven days of the survey. The lower back (49.7%) and the neck (36.5%) were the most affected sites. Working in the same position for a long time (43.5%) and not taking adequate breaks (31.3%) were the highest self-reported risk factors. Females had significantly higher odds of having pain in the upper back [aOR:2.49(1.27-4.85)], neck [aOR:2.15(1.22-3.77)], shoulder [aOR:2.8 (1.54-5.11)], hips [aOR:9.46 (3.95-22.68)] and knee [aOR:3.8(1.99-7.26)].

CONCLUSIONS

Females, who are NOs, work for > 48 h per week, and fall in the obese category were significantly at more risk of developing MSDs. Working in an awkward position, treating an excessive number of patients in a day, working in the same position for a long period, performing repeated tasks, and not having enough rest breaks were significant risk factors for MSDs.

Is telemedicine a holy grail in healthcare policy: clinicians' and patients' perspectives from an Apex Institution in Western India

BACKGROUND

This study aimed to explore the perception of doctors regarding telemedicine consultations and the level of patient satisfaction with the services received through teleconsultations.

METHODS

This cross-sectional study was conducted on clinicians who provided teleconsultations and patients who received teleconsultations in an Apex healthcare institution in Western India. Semi-structured interview schedules were used to record the quantitative and qualitative information. Clinicians' perceptions and patients' satisfaction were assessed using two different 5-point Likert scales. Data were analyzed using SPSS v.23 using non-parametric tests (Kruskal Wallis and Mann-Whitney U).

RESULTS

A total of 52 clinicians who delivered teleconsultations and 134 patients who received teleconsultations from those doctors were interviewed in this study. For 69% of doctors, telemedicine was feasible to implement, and for the rest, it was challenging. Doctors believe telemedicine is convenient for patients (77%) and prevents the transmission of infection (94.2%). Difficulty in clinical evaluation (73%), communication (55.7%), network connectivity (34%), diagnosis and investigations (32%), and patients' e-illiteracy (32%) were the most common challenges faced by clinicians. Patients' experiences were positive in terms of ease of registration (82.1%), audio quality (100%), freedom to discuss medicine (94.8%), and comprehension of the diagnoses (88.1%). Patients expressed satisfaction with the length of the teleconsultation (81.4%), the advice and care they received (78.4%), and the manner and communication of the clinicians (78.4%).

CONCLUSIONS

Though there were some challenges in the implementation of telemedicine, the clinicians perceived it quite helpful. The majority of the patients were satisfied with teleconsultation services. Difficulty in registration, lack of communication, and a deep-rooted mindset of physical consultations were the primary concerns from the patient side.

Challenges Faced by Cancer Patients in Receiving Health Services During the COVID-19 Pandemic in a Tertiary Care Hospital in Rajasthan

BACKGROUND

Amidst the COVID-19 pandemic, cancer patients may have faced difficulty accessing health care. This study explored the challenges experienced by cancer patients in availing of healthcare during the pandemic, as well as the vaccination status and prevalence of COVID-19 infection among cancer patients in the year 2021.

METHOD

A cross-sectional study was conducted in a tertiary care hospital in Jodhpur, Rajasthan, to interview 150 patients from the oncology department using convenience sampling. Face-to-face interviews lasted for 20-30 minutes. The first segment of the pretested semi-structured questionnaire was directed at obtaining the patient's socio-demographic characteristics, while the second segment focused on the problems that patients encountered during the pandemic in receiving cancer care. The data were analyzed using Statistical Packages for Social Sciences (SPSS) software (IBM Corp., Armonk, NY).

RESULTS

Several constraints, such as a lack of transportation services, difficulty in availing outpatient department (OPD) and teleconsultation services, long waiting times, and deferred surgeries and therapies, have hampered cancer care. COVID-19 mitigation measures further imposed additional stress and financial burden on cancer patients. Moreover, there was low vaccination coverage among cancer patients, which increases their probability of acquiring an infection.

CONCLUSION

Policy reforms must prioritize cancer care in India to maintain a continuum of care by ensuring medication, teleconsultation, uninterrupted treatment, and complete vaccination to decrease the risk of COVID-19 infection and facilitate patient compliance with the healthcare delivery system.

Challenges in the Implementation of the Rajasthan Pneumoconiosis Policy

OBJECTIVES

"Silicosis" is a leading cause of occupational morbidity globally. In Rajasthan, India silicosis has been recognized as an epidemic, resulting in the development of a new pneumoconiosis policy in 2019. This study was conducted to provide an overview of the policy implementation regarding the detection, prevention, and control of silicosis.

METHODS

A qualitative study was carried out in the Jodhpur district of Western Rajasthan in which stakeholders were interviewed. Themes were identified regarding prevention, detection, diagnosis, and certification, and organized by stakeholder role. Data were retrieved from the Silicosis Grant Disbursement Portal of the Government of Rajasthan to present an overview of the existing system for detection, prevention, and control of silicosis and to determine the delays in various aspects.

RESULTS

A total of 35 stakeholders were interviewed. There was low awareness regarding the prevention, detection, diagnosis, and rehabilitation of silicosis amongst multiple stakeholders. There is a need for robust enforcement in mining units regarding silicosis prevention and screening. Unregistered mining activities and migration of mineworkers are major challenges in the detection of silicosis cases. Misdiagnosis and low notification rates prevent workers from accessing resources. There are myriad reasons for delays in workers receiving diagnosis and benefits, which have systemic roots but can be uprooted through rigorous implementation of the legislative provisions.

CONCLUSION

There are several well-established pieces of legislation to protect the rights of mineworkers; however, there are gaps in the effective implementation of various provisions that require immediate attention to address the challenges faced during the prevention, detection, diagnosis, and rehabilitation of workers with silicosis.

Barriers and facilitators to COVID-19 screening at Jaipur International Airport, India

Background

Airports pose a possible threat in facilitating global disease transmission within the community which may be prevented by rigorous systematic entry-exit screening. This study captures the perception of stakeholders on barriers and facilitators of coronavirus disease 2019 (COVID-19) screening. Further, key outcomes viz. total passengers screened, suspected cases, and confirmed cases were assessed.

Methods

An inductive-deductive mix-method thematic analysis was conducted to capture qualitative data of key stakeholders on COVID-19 disease screening at Jaipur International Airport. Additionally, secondary data retrieved from Rajasthan Medical & Health Department team deployed for COVID-19 airport screening were analyzed.

Results

Jaipur International Airport screened 4565 passengers (Males = 4073 and Females = 492) with 23 suspected cases during an outlined period of declaration of Pandemic to Lockdown in India (11 to 24 March 2020). Total 65 passengers had travel history from China (3 from Wuhan). The mean average age of passengers was 40.95 ± 7.8 years. The average screening time per passenger was 2-3 min with a load of 25-90 passengers per team per flight. Fishbone analysis of screening challenges revealed poor cooperation of passengers, masking symptoms, apprehension, and stigma related to quarantine. Moreover, inadequate human resources and changing guidelines overburdened healthcare providers. But, perception of risk, and social responsibility of travelers together with supportive organization behavior act as facilitators. Overall, groundwork on airport screening was insightful to propose key action areas for screening.

Conclusions

Globally, COVID-19 has an impact on health infrastructure and international travel. International coordination with streamlined screening will go an extended way in virus containment.

Challenges in implementation of mother milk banks in Rajasthan: A situational analysis

BACKGROUND

Breastmilk is the baby's "first vaccine". Donated human milk (DHM) is the next best alternative when a mother's milk is not available, as recommended by WHO- UNICEF. DHM as a nutritional source provides similar immune protection and may prove revolutionary in reducing neonatal morbidity and mortality. The study aimed to explore the challenges in the implementation of selected Mother Milk Banks (MMBs) of Rajasthan.

MATERIAL AND METHODS

A qualitative in-depth interview of key stakeholders was conducted to know the various facets of the challenges in milk banking practices using the Root Cause Analysis framework.

RESULTS

The system challenges identified in the functioning of AMMBs were lack of recurring funds, dedicated lactational counselors, and trained technicians. Databases for demand-supply estimates were also lacking. The community challenges were low acceptance of DHM due to safety concerns, risk of disease transmission, and quality of donated milk. Moreover, the religious stigma and cultural beliefs regarding the transfer of heredity traits and decrease in mother-child affection act as barriers in donating milk.

CONCLUSION

For acceptance and availability of DHM, Social Behavior Communication Change (SBCC) interventions must be incorporated early during the antenatal check-up period. Our study highlighted the role of education; motivation by healthcare providers has a major influence on infant feeding choices. In a developing country such as India, where the frameworks concerning the development of mother milk banks are still maturing, our study findings provide baseline information to address the barriers in the implementation of mother milk banks in India.

Transcatheter Edge-to-Edge Repair of Systemic Tricuspid Valve in Extracardiac Fontan Circulation

Transcatheter edge-to-edge valve repair can improve clinical outcomes in otherwise high-risk surgical patients. This is a first-in-human procedure outlining transcatheter edge-to-edge valve repair of a systemic tricuspid valve in an extracardiac Fontan patient born with hypoplastic left heart syndrome with prohibitive surgical risk. (Level of Difficulty: Advanced.)

Out-of-pocket spending on hypertension and diabetes among patients reporting in a health -care teaching institute of the Western Rajasthan

Background:

Across the globe, morbidity and mortality due to non-communicable diseases (NCDs) are major public health issues. The resulting concern is not just epidemiological but also about the economic consequences at the household level.

Objective:

To assess the various facets of out-of-pocket spending (OOPs) incurring on NCDs, namely hypertension and diabetes on patients attending a healthcare teaching institute in Rajasthan.

Methodology:

This cross-sectional study involves patients older than 18 years attending either out-patient clinics or who were admitted in the wards in a healthcare teaching institute for seeking care for diabetes or hypertension. Four hundred patients were chosen purposively and a pretested questionnaire was used to elicit information on incurring OOPs for NCDs. Descriptive statistics (like percentage, mean, median, and standard deviation) were calculated.

Results:

The study shows a significant expenditure other than out-patient, in-patient admissions, in the form of personal expenditure and loss of employment, amounting to 31.86 and 34.07%, respectively, of the mean total expenditure. In a quarter (3 months), the mean total expenditure is ₹ 9014.37 ± 6452.37. On average, the OOP expenditure per visit for an out-patient visit was ₹370.54 ± 237, while for the patients admitted to the hospital, the average OOPs was ₹1564.72 ± 1310.5.

Conclusions:

Health expenditures can contribute toward the impoverishment of many segments of the community. Undoubtedly, numerous people may tend to neglect the needed care for NCDs due to financial hurdles. Thus, there is a need to develop NCD care management centers with health insurance packages and make them accessible for all.

Assessment of e-aushadhi program (drug inventory e-health initiative in Rajasthan) using benefit evaluation framework

Background:

E-aushadhi is a drug supply chain management initiative of the Rajasthan government. This study is conducted to assess this e-health program as evidence is lacking in this context

Methods:

A mix-method study was conducted. Primary data were recorded from key stakeholders using qualitative interviews. Secondary data were collected from internet-based searches, reports, documents, and available literature. Findings were contextualized into the Benefit-Evaluation framework using six dimensions

Results:

E-aushadhi provides a systematic approach for sourcing, storing, and re-distribution of essential medicine through its three-tier structure. Its user-friendly dashboard entails accurate entries, customizable reports, and easy tracking. It has reduced workload and improved information management with timely drug supply while allowing monitoring with key performance indicators

Conclusions:

E-aushadhi has been successful in improving beneficiary access at public health facilities and may act as a backbone architecture for various digital interventions in the National Digital Health Mission that supports the universal health coverage.

QT Interval Dynamics and Cardiovascular Outcomes: A Cohort Study in an Integrated Health Care Delivery System

Background

Long QT has been associated with ventricular dysrhythmias, cardiovascular disease (CVD) mortality, and sudden cardiac death. However, no studies to date have investigated the dynamics of within‐person QT change over time in relation to risk of incident CVD and all‐cause mortality in a real‐world setting.

Methods and Results

A cohort study among members of an integrated health care delivery system in Northern California including 61 455 people (mean age, 62 years; 60% women, 42% non‐White) with 3 or more ECGs (baseline in 2005–2009; mean±SD follow‐up time, 7.6±2.6 years). In fully adjusted models, tertile 3 versus tertile 1 of average QT corrected (using the Fridericia correction) was associated with cardiac arrest (hazard ratio [HR], 1.66), heart failure (HR, 1.62), ventricular dysrhythmias (HR, 1.56), all CVD (HR, 1.31), ischemic heart disease (HR, 1.28), total stroke (HR, 1.18), and all‐cause mortality (HR, 1.24). Tertile 3 versus tertile 2 of the QT corrected linear slope was associated with cardiac arrest (HR, 1.22), ventricular dysrhythmias (HR, 1.12), and all‐cause mortality (HR, 1.09). Tertile 3 versus tertile 1 of the QT corrected root mean squared error was associated with ventricular dysrhythmias (HR, 1.34), heart failure (HR, 1.28), all‐cause mortality (HR, 1.20), all CVD (HR, 1.14), total stroke (HR, 1.08), and ischemic heart disease (HR, 1.07).

Conclusions

Our results demonstrate improved predictive ability for CVD outcomes using longitudinal information from serial ECGs. Long‐term average QT corrected was more strongly associated with CVD outcomes than the linear slope or the root mean squared error. This new evidence is clinically relevant because ECGs are frequently used, noninvasive, and inexpensive.

Torsade de pointes: A nested case-control study in an integrated healthcare delivery system

Background

TdP is a form of polymorphic ventricular tachycardia which develops in the setting of a prolonged QT interval. There are limited data describing risk factors, treatment, and outcomes of this potentially fatal arrhythmia.

Objective

Our goals were as follows: (1) to validate cases presenting with Torsade de Pointes (TdP), (2) to identify modifiable risk factors, and (3) to describe the management strategies used for TdP and its prognosis in a real‐world healthcare setting.

Methods

Case–control study (with 2:1 matching on age, sex, and race/ethnicity) nested within the Genetic Epidemiology Research on Aging (GERA) cohort. Follow‐up of the cohort for case ascertainment was between January 01, 2005 and December 31, 2018.

Results

A total of 56 cases of TdP were confirmed (incidence rate = 3.6 per 100,000 persons/years). The average (SD) age of the TdP cases was 74 (13) years, 55 percent were female, and 16 percent were non‐white. The independent predictors of TdP were potassium concentration <3.6 mEq/L (OR = 10.6), prior history of atrial fibrillation/flutter (OR = 6.2), QTc >480 ms (OR = 4.4) and prior history of coronary artery disease (OR = 2.6). Exposure to furosemide and amiodarone was significantly greater in cases than in controls. The most common treatment for TdP was IV magnesium (78.6%) and IV potassium repletion (73.2%). The in‐hospital and 1‐year mortality rates for TdP cases were 10.7% and 25.0% percent, respectively.

Conclusions

These findings may inform quantitative multivariate risk indices for the prediction of TdP and could guide practitioners on which patients may qualify for continuous ECG monitoring and/or electrolyte replacement therapy.

736Low Birth weight in new born, anaemia in pregnancy in Fluoride endemic areas of Rajasthan

Background

Rajasthan has been documenting severe anaemia in pregnancy, resulting in low birth weight. Current study was planned to explore potential linkages between exposure to fluoride, anaemia in pregnancy and low birth weight in infant.

Methods

Antenatal mothers from one fluoride endemic district (FD) and one non-fluoride endemic district (NFD) of western Rajasthan were recruited and followed up till delivery. Data included socio-demographic, lifestyle, diet, medication history. Lab Investigations included Hb, Urinary Fluoride.

Results

Out of total 1401 women, mean age of women from FD were 23.87 (+ 3.8) yrs and from NFD were 25.53(+ 3.82) yrs. Mean fluoride values in the urine samples of pregnant females were found to be 2.06 (0.0 to 14.4 mg/L) in FD and 1.43 (0.00 to 12.7 mg/L) in NFD. Mean fluoride values in water samples were 0.72 (0.0 to 3.80 mg/L) in FD and 0.21 (0.0 to 2.69 mg/L) in NFD. Mean weight of newborn from FD were 2.92 (+ 0.47) yrs and from NFD were 2.94 (+ 0.56) kg. 22% Newborn in FD and 18% in NFD had low birth weight.

Conclusions

Infants born in Fluoride endemic area have lower birth weight as compared to non-Fluoride endemic area. Antenatal women in Fluoride endemic areas are more anaemic.

Key messages

Fluoride endemicity is an important factor to be considered while addressing Anaemia in pregnancy and Low Birth Weight Babies in Western Rajasthan, India.

A novel subtraction diversity array distinguishes between clinical and non-clinical Streptococcus uberis and identifies potential virulence determinants

Streptococcus uberis is an important bovine mastitis pathogen, but not all isolates have equal capacity to cause disease. The aims of this study were to identify possible virulence-associated genes that could be used to identify isolates with enhanced virulence. DNA from a pool of putative commensals was subtracted from a clinical pool resulting in a set of DNA sequences (probes) that were enriched in the clinical mastitis group. The probes were hybridised with DNA from a collection 29 isolates from cases of clinical mastitis and isolates not associated with disease. Hybridization revealed five major clusters. The first cluster (7 isolates) consisted almost entirely of commensals, while the second (7 isolates) was mixed. The remaining three clusters contained 15 S. uberis isolates from cows with clinical mastitis. Twenty-six probes were selected for sequencing based on principal component analysis (PCA) or their presence mainly in clinical isolates. PCA identified five probes with clear differences in intensity between signals from clinical isolates and commensals; these probes could represent novel virulence determinants. Manual inspection of arrays identified genes prominent among clinical isolates that specify carbohydrate and lipid metabolism (possible role in the growth or survival of S. uberis in milk) and genes specifying hypothetical proteins, possibly novel virulence factors. The common occurrence, among clinical isolates, of probes having homology with transposases and insertion sequences suggests recent acquisition of factors that could be associated with virulence. These results suggest the existence of a subset of S. uberis with enhanced virulence, due possession of virulence-associated gene sequences.