Intestinal bacterial and parasitic infections among food handlers in a tertiary care hospital of North India.

BACKGROUND: Intestinal infection is still an important public health problem in developing countries like India. Food handlers may be infected by a wide range of enteropathogens and have been implicated in the transmission of many infections to the public in the community and to patients in hospitals. AIM: To study the presence of enteropathogenic bacteria and parasites in food handlers working in the food service establishments of a tertiary care centre in North India. METHOD: The stool samples received from food handlers during January 2001 to December 2006 were examined by wet mount, iodine mount and modified acid fast staining directly and after formol ether concentration technique for parasites. For enteropathogenic bacteria, samples were inoculated onto MacConkey's agar, Deoxycholate Citrate Agar, Xylose Lysine Deoxycholate agar (XLD) as per the WHO protocol. RESULTS: During the years 2001-2006 respectively, 8.75%, 16%, 1.4%, 6.75%, 2.56% and 6.75% food handlers were infected with enteropathogens. The parasitic infections in our study were 1.3 to 7% while the enteropathogenic bacteria were reported from 0% to 13.3% during the years 2001-6. Giardia was the most common parasite while Shigella was the most common bacteria isolated from food handlers. During the year 2001, there was an outbreak of ETEC in the neonatal ICU, Advanced Paediatric Centre, PGIMER, which was traced back to a food handler involved in the preparation of the milk feed. CONCLUSION: Routine screening of food handlers is a valuable tool for prevention of nosocomial food-borne infections.

Kinetics of microfilaraemia & antigenaemia status by Og(4)C(3) ELISA in bancroftian filariasis.

BACKGROUND & OBJECTIVE: Bancroftian filariasis caused by Wuchereria bancrofti is endemic in many parts of India. In recent years diagnosis of W. bancrofti infection has been revolutionized with the availability of filarial antigen tests, which is important in monitoring success of chemotherapy. We carried out this study to measure microfilariaemia and antigenemia levels in bancroftian microfilariae (mf) carriers at 1 yr follow up after chemotherapy, in lymphoedema patients and in endemic controls from a filariasis endemic area in Tamil Nadu State using Og(4)C(3) ELISA to identify the best marker to assess success of chemotherapy. METHODS: Serum samples were collected from 30 bancroftian microfilaremic (Mf) carriers pre-treatment and at sequential intervals (7,30,60,90,180 and 365 days) following treatment with diethylcarbamazine (DEC:6mg/kg body weight, single dose), 30 lymphoedema patients (without treatment) at periodic intervals, and 68 control subjects (24 endemic normal subjects in filariasis endemic area in Tamil Nadu State, 24 non-endemic normal subjects residing in Chandigarh, India; 5 brugian filariasis, 5 endemic control subject in brugian filariasis endemic area and 10 other disease controls). The circulating antigen of W. bancrofti was measured quantitatively using Og(4)C(3) ELISA kit. RESULTS: In Mf carriers, there was no significant difference in microfilariae count in pre- and post-treatment (PT) samples till day 30 while significant differences were observed in pre- and sequentially collected post-treatment (PT) samples day 60 to 180 (P<0.001), day 365 (P<0.005). However, there was no significant difference in antigenaemia levels between pre-treatment (day 0) and PT samples collected on day 7 onwards till day 365. Though of the 19 patients who could be followed up till 365 days PT, 4 (21%) were amicrofilaraemic, none became antigen negative. No significant difference was found in antigenaemia levels in sequentially collected samples from lymphoedema patients. Significant differences were observed in antigenaemia levels in samples collected at the start of study in mf carriers as compared to lymphoedema patients and endemic normal subjects (P<0.001). Subjects (non-endemic control) residing in filariasis free area (24), brugian endemic area (5), B.malayi infected patients (5) and patients with other parasitic diseases (10) were found antigen negative. INTERPRETATION & CONCLUSION: Annual single dose of DEC therapy alone may not result in complete clearance of infection and detection of antigenaemia rather than microfilaraemia may be taken into consideration as an indicator of successful chemotherapy. The study supports the earlier view that filarial antigenaemia is relatively common in amicrofilaraemic and asymptomatic subjects in endemic areas and further studies are needed to determine the clinical significance, prognosis and effective management of such infections in endemic areas.

Multidrug resistance in amoebiasis patients.

BACKGROUND & OBJECTIVES: Amoebiasis, caused by Entamoeba sp. a protozoan parasite, is a major public health problem in tropical and subtropical countries. The symptomatic patients are treated by specific chemotherapy. However, there are reports of treatment failure in some cases suggesting the possibility of drug resistance. The present study was therefore planned to assess the presence and expression of mRNA of multidrug resistance (MDR) gene in clinical isolates of Entamoeba histolytica and E. dispar. METHODS: Forty five clinical isolates of Entamoeba sp. [E. histolytica (15) and E. dispar (30)] were maintained in polyxenic followed by monoxenic medium. DNA and total RNA were extracted from clinical isolates of Entamoeba sp. and from sensitive strain of E. histolytica (HM1: IMSS) and subjected to polymerase chain reaction (PCR) and multiplex reverse transcription (RT)-PCR techniques. RESULTS: The 344 bp segment of E. histolytica DNA was seen by PCR using primers specific to EhPgp1 in all clinical isolates and sensitive strain of E. histolytica. Over expression of EhPgp1 was observed only in resistant mutant of E. histolytica; however, transcription of EhPgp1 was not seen in any clinical isolates and sensitive strain of E. histolytica. INTERPRETATION & CONCLUSION: The findings of the present study indicate that, so far, drug resistance in clinical isolates of E. histolytica does not seem to be a major problem in this country. However, susceptibility of clinical isolates of E. histolytica against various antiamoebic drugs needs to be investigated for better management.

Pathophysiology of visceral leishmaniasis - some recent concepts.

Visceral leishmaniasis is characterized by diversity and complexity of clinical manifestations ranging from asymptomatic infection to life threatening illness. Experimental evidence and clinical studies indicate multifaceted role of various factors leading to parasite survival and multiplication. In early stage of infection, generation of reactive oxygen and nitrogen intermediates play significant role in curtailing the parasite multiplication while in later phase on one hand, hepatic resistance is expressed by the dominant role played by nitric oxide synthase (NOS)-2 gene regulation and on the other hand, production of inhibitors of NOS-2 gene expression, interleukin 10 (IL-10) and transforming growth factor beta (TGFbeta) correlate well with reduced parasite killing. The hepatic infection is usually self-limiting due to production of multiple cytokine responses including moderate level of tumour necrosis factor (TNF) while in spleen excess TNF mediates destructive pathology. CD8+ T cells appear to play multiple roles comprising both cytotoxic activity and secretion of cytokines and chemokines. Capacity to produce ThI cytokines is associated with asymptomatic or subclinical self-healing infection. However, in symptomatic patients, Th I cytokine production is not depressed but there appears to be unresponsiveness to the stimuli of these cytokines. Experimental evidences indicate genetic basis for such a phenomenon.

Drug resistance in amoebiasis.

Amoebiasis caused by Entamoeba histolytica, is a major public health problem in developing countries. Morphologically similar E. dispar is non pathogenic. Because of the redefinition of E. histolytica and E. dispar, and the limited number of antiamoebic drugs available, a new approach to treat such individuals is necessary. The cost of treating asymptomatic individuals is highly exorbitant and not justifiable. The indiscriminate use of antiamoebic drugs can result in increased minimum inhibitory concentration (MIC) values against Entamoeba species, and treatment failure may emerge as an important public health problem. Development of new antiamoebic drugs is still in infancy and vaccine development appears to be distant dream. In future, the development of drug resistance may seriously affect the control of disease. This review discusses the factors involved in drug resistance mechanisms developed by the parasite.

Prevalence of anti-cysticercus antibodies in slum, rural and urban populations in and around Union territory, Chandigarh.

A comparative analysis for the prevalence of anti-cysticercus antibodies was carried out in urban, rural and slum population in & around Union territory of Chandigarh. Prevalence of anti-cysticercus antibodies in different population groups was found to be 17.3% with highest prevalence (24%) reported from slum areas followed by that of rural areas (20%) and least in the urban organized sectors (8%). Only 8% of the seropositive individuals had history suggestive of neurocysticercosis. Overall, females showed the highest anti-cysticercus response of 20.4%.

Comparative analysis of intestinal parasitic infections in slum, rural and urban populations in and around union Territory, Chandigarh.

A study was conducted in and around the union Territory, Chandigarh, India to estimate the prevalence of intestinal parasitic infections in different population groups. The stool samples from a total of 600 subjects selected by cluster sampling technique were examined by direct microscopy. The prevalence of intestinal parasitic infections was found to be 14.6% with highest prevalence of 19% from the slum area. Children were the most commonly affected group (18%) with those from slums showing the highest prevalence (24.6%). The most common parasite was Giardia (5.5%) followed by H. nana and Ascaris (2.8% and 2.7% respectively).

Utility of specific IgG4 response in saliva and serum samples for the diagnosis and follow up of human neurocysticercosis.

This study was aimed to analyze the Ig subtypes and IgG1 and IgG4 subclass responses to crude soluble extract (CSE) antigen and Ag B of Cysticercus cellulosae in pre and post treatment (PT) saliva and serum samples for the diagnosis and follow-up of neurocysticercosis (NCC) patients. Saliva and serum samples collected from 55 patients (15 highly suggestive of NCC clinically and radiologically, 10 hydatidosis, 10 other helminthic infections, 10 tubercular meningitis, 10 neurological disorders other than NCC), 15 normal healthy subjects and 10 NCC patients at 1, 3 and 6 months following albendazole therapy were analyzed for specific IgG, IgG1, IgG4, IgM and IgA antibody responses by ELISA. With the use of CSE Ag, the rank orders in saliva for sensitivity was IgG (71.4%) > IgG1 (68.2%) > IgG4 (65.2%) > IgM (57.7%) > IgA (55.5%) and specificity IgG1 = IgA (93.2%) > IgG = IgG4 = IgM (91.6%) while in serum, sensitivity was IgG (78.9%) > IgG1 (71.4%) > IgG4 (68.2%) > IgA (65.2%) > IgM (62.5%) and specificity IgG1 = IgG4 (90.2%) > IgA (85.9%) > IgG (83.3%) > IgM (82.1%). With the use of Ag B in saliva, the sensitivity was IgG (65.2%) > IgG1 = IgG4 (62.5%) > IgM = IgA (55.5%) and specificity with the use of saliva was IgG1 = IgG4 = IgM (94.8%) > IgG (93.2%) > IgA (91.6%) while with serum the sensitivity was IgG = IgG1 (68.2%) > IgG4 (65.2%) > IgA (62.5%) > IgM (57.7%) and specificity was IgG1 (93.2%) > IgG4 = IgM (91.6%) > IgA (90.2%) > IgG (87.3%). Comparative analysis of antibody responses in patients with single Vs multiple CT scan lesions indicated higher sensitivity in multiple lesion patients. Antibody responses in PT samples indicated that the undetectable IgG4, IgM and IgA responses in saliva samples correlated well with the CT scan reports while in serum samples, responses persisted longer. In conclusion, this study indicated that due to the lower sensitivity of IgM and IgA responses in pretreatment samples, detection of IgG4 subclass in saliva to either CSE Ag or AgB may serve better marker in the NCC follow-up.

Comparative evaluation of hexokinase isoenzyme typing and antigen detection for differentiation of Entamoeba histolytica and Entamoeba dispar.

Entamoeba histolytica, the causative organism of invasive amebiasis is a potential pathogen, while asymptomatic infection is caused by E. dispar. Differentiation of the species is not possible on the basis of morphological characters by microscopic examination. In the present study an attempt has been made to differentiate E. histolytica from E. dispar in 45 isolates obtained from culture and direct stool samples respectively on the basis of hexokinase isoenzyme analysis and Tech Lab ELISA. A 100% correlation was found between these two techniques. However, Tech Lab E. histolytica antigen detection test was found to be both rapid and technically simple. Its use in diagnosis and epidemiological studies is recommended.

Intestinal parasites and intra familial incidence in a low socio-economic area of Chandigarh (North India).

A total of 550 stool samples were collected from a low socio economic population of Chandigarh (North India) and examined macroscopically and microscopically, to determine the prevalence of intestinal parasitic infections and their familial incidence. The overall prevalence rate was 19.3%. Ascaris lumbricoides and Giardia lamblia were the commonest, affecting 51 (9.3%) and 33 (6.0%), respectively. In 17 (22.7%) families the same parasite was observed to infect multiple family members, which included A.lumbricoides (in 9 families), G. lamblia (in 7 families) and H. nana (in 1 family). The results of present study indicate that there is a high prevalence of parasitic infection in the community where personal hygiene and sanitary conditions are poor and may be one of the contributing factors for transmission within the families. Intervention strategies including health education program should be designed and implemented to control parasitic infections.

In vitro comparative kinetics of adhesive and haemolytic potential of T. vaginalis isolates from symptomatic and asymptomatic females.

The host parasite relationship and pathogenic mechanisms of the commonly reported sexually transmitted urogenital disease, trichomoniasis, are poorly understood. This study was planned to correlate the adhesion properties of Trichomonas vaginalis isolates from symptomatic and asymptomatic women to vaginal epithelial cells in vitro (in presence and absence of L. acidophilus) and to ascertain the haemolytic activity of the isolates, in order to assess these properties as possible markers of pathogenicity. Cytoadherence assay study shows the significant difference in adhesion only up to first 15 minutes of incubation in symptomatic versus asymptomatic isolates. The presence of L. acidophilus was found to be more effective in enhancing the attachment of T. vaginalis in a time dependent manner mostly operative through its pH lowering effect, whereas the excretory secretory products of L. acidophilus reduced the attachment in case of both symptomatic and asymptomatic isolates. Amount of haemoglobin released by isolates from symptomatic patients was significantly higher than by the isolates from asymptomatic women. This investigation forms the basis for future studies to explore the role of other known virulence factors of T. vaginalis in initiation and persistence of vaginal infection by the parasite.

Transfusion associated infections: a threat to life.

Blood transfusion is indispensable in the management of many haematological diseases and has become the mainstay in major surgical procedures. Transfusion-transmitted infections have been a major threat to life since the dawn of transfusion therapy. The authors have highlighted the different viral, parasitic and bacterial infections associated with transfusion and have focussed on the precautionary measures that can be implemented for prevention of the infections along with a brief review of the literature.

Human toxocariasis and ascariasis: concomitant parasitism in Srinagar, Kashmir, India.

Human toxocariasis caused by Toxocara canis is common in both developing and developed countries and leads to visceral larva migrans with high morbidity and mortality. Ascariasis caused by Ascaris lumbricoides, too has global distribution and in India, high prevalence rate has been reported in Kashmir (J & K State). Both nematode parasites, Toxocara canis and A. lumbricoides require similar biological and environmental conditions for the development of eggs in soil. Therefore, the present study was attempted to detect the antibody response to T. Canis excretory-secretory (ES) antigen by enzyme linked immunosorbent assay in patients attending Sher-I-Kashmir Institute of Medical Sciences, Soura, Srinagar, Kashmir to assess the magnitude of human toxocariasis in Kashmir, the highly endemic area of ascariasis. Interestingly, it was observed that 38 (82.60%) out of 46 patients harbouring Ascaris Iumbricoides had positive antibody response to T. Canis ES antigen while none of the 15 normal healthy subjects from the same endemic zone, 25 from low endemic zone Chandigarh and 15 from other parasitic infections (hookworm, hydatidosis, cysticercosis) indicated detectable positive response. Majority of the ascariasis positive patients studied were in the age group of 21-40 years. However, one ascariasis patient studied in the age group of 1-10 years (4 years old) had also positive antibody response to T. Canis antigen. This study is the first report of human toxocariasis in Kashmir, India, an endemic zone for ascariasis and emphasizes the need for detailed epidemiological study for the ultimate prevention and control of this disease

A serological study of human toxocariasis in north India.

BACKGROUND: Human toxocariasis owing to lodgement of the larvae of Toxocara canis in different organs can result in serious clinical syndromes such as visceral larva migrans or ocular larva migrans. Detection of an antibody response to Toxocara canis excretory-secretory (TES) antigen in serum samples is sensitive and specific for diagnosis and epidemiological surveys. To assess the extent of this problem in northern India, we tested the antibody response to the TES antigen by ELISA technique in subjects residing in a rural area near Chandigarh and in patients attending Nehru hospital, Chandigarh and clinically suspected to have toxocariasis. METHODS: Serum samples were collected from 94 randomly selected subjects, residents of Kheri village, Ambala district, Haryana; 30 patients clinically suspected to have toxocariasis attending Nehru hospital, Chandigarh; 25 control patients and 15 normal healthy individuals. These were subjected to ELISA technique for detection of an antibody response to TES antigen usinga commercial kit (LMD Laboratories Inc. Ca. USA). All the samples were tested in duplicate and positive samples were tested by a different kit (Melotec Biotechnology, Spain). RESULTS: Of the 94 subjects residing in Kheri village and 30 clinically suspected toxocariasis patients, 6 (6.4%) and 7 (23.3%), respectively, were seropositive for anti-Toxocara antibody response. A history of pica and/or contact with puppies could not be obtained from all the subjects/patients, hence the exact mode of transmission could not be ascertained. However, 3 (3.2%), 2 (2.13%) and 1 (1.06%) seropositive subjects in Kheri village were in the age groups of 1-10, 11-20 and 21-30 years, respectively, while 4 (13.33%) and 3 (10%) seropositive patients who attended Nehru hospital, Chandigarh were in the age groups of 1-10 and 21-30 years, respectively. None of the control patients/healthy individuals were seropositive. CONCLUSION: A positive antibody response to TES antigen in 6.4% subjects residing in a rural area near Chandigarh and in 23.3% of patients clinically suspected to have toxocariasis indicates that human toxocariasis may be endemic in certain regions of northern India. A detailed epidemiological study is needed to determine the extent of this problem.

Seroepidemiological study of toxoplasmosis in different sections of population of Union Territory of Chandigarh.

Infections with Toxoplasma gondii in humans are usually asymptomatic or in the form of mild febrile illness. Primary infection in pregnant women may result in congenital toxoplasmosis while infection in immunocompromised subjects like AIDS patients may cause potentially fatal toxoplasma encephalitis. In India, only a few studies in hospital based patients have shown prevalence of toxoplasmosis to be between 1.5 and 21%. No field study involving general population is available. The present study investigates the prevalence of toxoplasmosis in subjects from rural, urban and urban slum populations of Union Territory, Chandigarh. Serum samples from 500 subjects from each group were collected and antitoxoplasma IgM and IgG was detected by conventional micro ELISA technique using soluble Toxoplasma gondii tachyzoite antigen. Overall 5.4% subjects were positive for IgM while 4.66% showed IgG antitoxoplasma antibodies. Amongst the three groups, significantly higher number of subjects in slum area (7.8%) showed IgM antibodies as compared to urban and rural areas (4.2% each). There was no significant difference in IgG positivity between three study areas. Prevalence of T. gondii specific IgG antibodies was significantly higher amongst females of both slum (7.31%) and rural area (8.44%) as compared to the males (2.85% and 3.27% respectively) in the same areas (p<0.05) and also to females of the urban area (2.98%, p<0.05). Prevalence of IgM antibodies was significantly higher (p<0.05) in females in the slum area (10.5%) as compared to females in the urban area (2.55%). In both urban and slum areas, highest IgM seropositivity was observed in age group 6-12 years (10% and 13.3% respectively), while in the rural area the highest IgM seropositivity was seen in the age group > or = 5 years (17.7%). These data indicate that majority of children are exposed to toxoplasma before 12 years of age and particularly in rural areas higher number of subjects acquire Toxoplasma gondii infection early in childhood probably as a result of higher exposure due to farming, poor hygiene and handling of animals.