A prospective study of phage types & biotypes of Salmonella enterica serotype Typhi isolated from hospitalized children in Kolkata, India.

BACKGROUND & OBJECTIVES: Kolkata and its suburbs in eastern India faced an epidemic of typhoid fever in 1990. A prospective, hospital and laboratory based study over a period of 12 yr (1990-2001), on the phage typing and biotyping pattern of Salmonella enterica serotype Typhi was carried out, to see if there has been a change. METHODS: A total of 338 S. enterica serotype Typhi isolates from 1491 blood samples were phage typed and biotyped. The mean age of isolation was calculated. RESULTS: The age distribution of subjects (neonates to 12 yr) has been analysed. Of the 338 (22.7%) isolates obtained, eight different S. enterica serotype Typhi phage types were detected. Biotype I (95.8%) was more prevalent as compared to biotype II (4.1%). Phage type E1 was the commonest phage type in Kolkata and its suburbs. INTERPRETATION & CONCLUSION: The mean age at isolation was found to be 6.7 +/- 3.3 yr. Biotype I was predominant and it was of interest that all strains of phage type E1 belonged to biotype I.

Decreasing trend in the occurrence of Salmonella enterica serotype Typhi amongst hospitalised children in Kolkata, India during 1990-2000.

In a prospective hospital based surveillance, 1454 children clinically diagnosed as typhoid fever were enrolled during the period between 1990 to 2000. Of them 336 (23.1%) children were positive for Salmonella enterica serotype Typhi by blood culture. A declining trend of hospitalization and identification of the pathogen was observed from 1992 to 2000 as compared to 1990-1991. A declining trend of resistance to the commonly used anti-typhoid drugs was seen in the S. enterica serotype Typhi isolates. Recently in 2000, nine strains were detected as ciprofloxacin resistant. Misuse and overuse of ciprofloxacin for the treatment of typhoid fever influenced the development of ciprofloxacin resistant strains of S. enterica serotype Typhi in and around Kolkata.

Isolation of Salmonella enterica serotypes from children with diarrhoea in Calcutta, India.

The prevalence of Salmonella enterica serotypes, antimicrobial susceptibility, and phage typing of serovers were studied. Clinical presentations of the infected cases were also examined. The study was carried out during August 1993-September 1996 in and around Calcutta, India. In total, 1,025 faecal samples from hospitalized diarrhoeal children were screened for enteropathogens. Four S. enterica serotypes were identified in 157 (15.3%) cases as a single pathogen. S. enterica serotype Typhimurium was detected in 110 (70%) cases. S. Seftenberg, S. Infantis, and S. Virchow were detected in 28 (17.8%), 14 (8.9%), and 5 (3.2%) cases respectively. S. Typhimurium was isolated from 11 (3.2%) non-diarrhoeal control children. All of these children had acute watery diarrhoea, and 5% of them had severe dehydration, 40% had some dehydration, and 55% had no dehydration. Vomiting, fever, and diffused pain in abdomen were the associated presentations of these children. Most (95%) of them recovered with oral rehydration therapy only and without any antibiotics. In-vitro susceptibility testing showed that 120 of the 121 S. Typhimurium strains isolated from cases and controls were resistant to the commonly-used drugs. Thirteen of the 121 strains were phage-typeable and belonged to the phage type 193. However, no clinical or epidemiological significance could be established with these typeable strains. The findings of the study indicate that diarrhoeagenic Salmonella is one of the major pathogens causing diarrhoeal diseases in eastern India.

Value of faecal leucocyte count as an indicator of invasiveness in mucoid diarrhoea.

Importance of faecal leucocyte count as an indicator of invasiveness in mucoid diarrhoea was studied. A total of 290 faecal specimen, 170 from mucoid diarrhoea and 120 from watery diarrhoea were examined for faecal leucocyte count under high power field (hpf) from rural children below four years of age during the period from November 1992 to October 1995. Faecal leucocyte count > 10/hpf was noted in 45.9% of mucoid diarrhoea as against 19.2% of watery diarrhoea (p < 0.0001) samples. From faecal samples with > 10 faecal leucocyte count, invasive pathogens could be recovered in 19 (24.5%) to none of 23 patients with watery diarrhoea (p < 0.006 Fisher exact test). This sample test appears to be of value as an indicator of invasiveness in mucoid diarrhoea in the absence of culture facility.

Isolation of Escherichia coli to detect faecal contamination of infants and their mothers in West Bengal.

The present study was undertaken to gain insight into the sources of faecal contamination of infants in rural Bengal. It was carried out in three villages near Calcutta, India, from June 1993 to August 1995 among 148 infants and their mothers. Escherichia coli was used as an indicator of faecal pollution. A total of 725 samples, including hand rinsings of children and mothers, feeding utensils and leftover food were examined. The total isolation rate of faecal E. coli was 30%. The isolation rates from hands of children and mothers were 17% and 40% respectively. The germs from 30% of utensils and 59% of leftover food and drinks were recovered further. The study highlights the precarious hygiene in rural Bengal.

Multi-drug resistant typhoid fever with diarrhea.

OBJECTIVE: To provide information about the characteristics of diarrheal stool in multi-drug resistant typhoid fever and observe the clinical course after treatment with furazolidone or ciprofloxacin. SETTING: Hospital based. SUBJECTS AND METHODS: Twenty one male children who were positive for multi-drug resistant S. typhi by blood and stool cultures, having diarrhea at the time of hospitalization comprised the subjects. Serum and stool electrolytes were estimated. Stool samples were also processed to detect established enteropathogens, leukocytes and red blood cells. Children were treated either with furazolidone or ciprofloxacin and evaluated till recovery. RESULTS: Mean (+/- SD) pre-admission duration of fever and diarrhea of these cases were 19.1 (+/- 5.6) and 15.8 (+/- 4.6) days, respectively. Stool character in 81% of the patients was watery with mean (+/- SD) volume of stool 51.4 (+/- 25.1) ml per kg body weight in the first 24 hours of observation. Leukocyte count varied between 20-49 per high power field in 66.7% stool samples. Occult blood was present in only 19% cases. Fecal red blood cells in high power field were detected in 52.4% cases. Mean fecal electrolytes (mmol/liter) were as follows: sodium-53.8, potassium-51.4, chloride-41.6 and total CO2-24.3. Most of the children (71.4%) had no dehydration and had normal serum electrolytes. The isolated strains of S. typhi were multi-drug resistant. These children were treated successfully either with furazolidone or ciprofloxacin. CONCLUSION: The stools of multi-drug resistant typhoid fever patients were watery with little blood. Their electrolyte contents were more similar to the diarrheal stool seen in shigellosis rather than cholera. Uncontrolled observations revealed that children recovered with furazolidone or ciprofloxacin therapy.

Comparison between the multiplex PCR, sensitivity to biotype specific phages & polymyxin B for biotyping of Vibrio cholerae O1.

A total of 196 Vibrio cholerae O1 strains isolated between 1970 and 1996 were biotyped by multiplex PCR, susceptibility to polymyxin B and sensitivity to biotype specific phages. We modified the multiplex PCR by increasing the primer concentration of tcpA to improve the results. Comparison of the results of modified multiplex PCR and sensitivity to biotype specific phages and to polymyxin B showed that multiplex PCR was as efficient as phage typing for biotyping of V. cholerae O1. All the strains of V. cholerae O1 could be accurately distinguished based on polymyxin B sensitivity. Thus our results show that susceptibility of strains of V. cholerae O1 to polymyxin B is the easiest method to biotype V. cholerae O1 and is feasible in most laboratories when compared with multiplex PCR and sensitivity to biotype specific phages.

Occurrence of diarrhoeal diseases in relation to infant feeding practices in a rural community in West Bengal, India.

In a rural community-based prospective study, diarrhoea in relation to the feeding patterns of a cohort of infants was studied. A total of 148 infants between the ages of 0 and 2 months were enrolled and followed until the completion of 1 year of age. Survival analysis showed that by the fourth month of age exclusive breastfeeding dropped by 75%. The proportion of complementary breastfeeding increased from 18.6 to 52.9% during the same period and to 83.7% by the eighth month. This study clearly highlights the tendency for early switch over from exclusive breastfeeding to complementary breastfeeding. Early weaning was associated with an incidence rate ratio (IRR) of 3.02 (95% CI 1.043-8.802). The IRR of 3.02 and its confidence limits (1.043-8.02) suggest a significant protective effect of exclusive breastfeeding against diarrhoea in infants. The results of this study indicate that promotion of exclusive breastfeeding has a potential role to reduce the incidence of diarrhoea amongst infants. The findings of this study will be useful for Diarrhoeal Disease Control Programme in reducing diarrhoeal morbidity.

Distribution of age-specific rotavirus antibody in human: a hospital-based study in Calcutta.

Sera obtained from 332 non-diarrhoeic individuals belonging to different age groups were tested by enzyme-linked immunosorbent assay method for detection of rotavirus antibody. All the sera were found to contain rotavirus antibody in varying titres, the highest being recorded in neonates which declined to the lowest by the age of 6 months with a rapid rise during the next 5 years. This study indicates the acquisition of rotavirus antibody in different age groups.

Enteropathogens associated with acute diarrhoeal diseases.

PIP: Five types of Escherichia coli are responsible for as much as 25% of all diarrheal diseases in developing countries. They tend to be transmitted via contaminated foods, particularly weaning foods, and water. They include enterotoxigenic, enteropathogenic, enteroadherent, enteroinvasive, and enterohemorrhagic E. coli. Shigella species are responsible for 10-15% of acute diarrheas in children less than 5 years old and the most common etiologic agents of childhood dysentery. Shigellosis is common in the warm season. An outbreak of shigella dysentery in West Bengal, India, had a high attack rate in children less than 5 years old and was resistant to many drugs. Nontyphoid Salmonella species cause watery diarrhea with nausea, cramps, and fever. Worldwide, various Salmonella strains exhibit resistance to ampicillin, chloramphenicol, and co-trimoxazole. Campylobacter jejuni produces watery diarrhea which, in 33% of cases and 1-2 days after onset, contains blood and mucus. Many normal healthy children in developing countries are carriers of C. jejuni. Vibrio cholerae O1 is endemic in parts of Africa and Asia (e.g., 5-10% of hospitalized diarrhea patients). The ElTor cholera biotype is responsible for the 7th pandemic. Other bacterial enteropathogens are Aeromonas species, Bacteroides fragilis, and Providencia alcalifaciens. Rotavirus is a major cause of sporadic and epidemic diarrhea among 6-23 month olds. Its incidence peaks in cold or dry seasons. Other viral enteropathogens are Norwalk virus, adenoviruses, astroviruses, and coronaviruses. In India, the prevalence of Entamoeba histolytica varies from 3.6% to 47.4%. It occurs equally in high and low socioeconomic classes. Giardia lamblia usually infects 1-5 year old children. Its transmission routes are food, water, and the fecal-oral route. Cryptosporidia produce acute watery diarrhea, especially in children less than 2 years old. Cryptosporidia diarrhea is common among AIDS patients. Oral rehydration therapy and proper feeding during and after diarrhea reduces deaths from diarrhea.^ieng

Validity of new phage typing scheme against Vibrio cholerae 01 biotype ElTor strains.

A total of 538 strains of V. cholerae 01 biotype ElTor were phage typed by the conventional Basu and Mukerjee and also the new typing scheme developed at the National Institute of Cholera and Enteric Diseases, Calcutta. The strains could be clustered into seven types by the new scheme as against only two by the conventional method. The results provide conclusive evidence on the validity of the new scheme for phage typing of V. cholerae strains.

Multi-drug resistant typhoid fever in hospitalised children. Clinical, bacteriological and epidemiological profiles.

A total of 592 children with clinical diagnosis of typhoid fever admitted to the Dr B. C. Roy Memorial Hospital for Children, Calcutta, India during the period between February 1990 and January 1992, were screened for Salmonella typhi by blood culture. S. typhi was isolated from 221 (37.3%) cases. The majority of the strains (92.3%) showed multi-drug resistant (MDR). They were resistant to chloramphenicol, ampicillin, tetracycline and trimethoprim-sulphamethoxazole. However, all the strains were uniformly (100%) susceptible to gentamicin, amikacin, furazolidone, norfloxacin and ciprofloxacin. Minimum inhibitory concentration of the antimicrobial agents against the resistant strains of S. typhi ranged between 200 and > 1600 micrograms/ml. Phage type 0 was most frequently encountered. The rate of isolation of S. typhi was more or less the same in all the pediatric age groups. The majority of the cases came from lower socio-economic classes with poor personal hygiene. Fever was the main presenting feature in all the cases. Other associated features of the MDR typhoid fever cases, who were uncomplicated during admission, were headache (36.0%), chill and rigor (23.2%), diarrhea (37.2%), anorexia (26.2%), vomiting (23.8%), cough (18.0%) and abdominal pain (19.8%). Hepatosplenomegaly was present in 42.4% cases. However, complications were less frequently encountered among the MDR typhoid fever cases who were uncomplicated during admission and treated as in-patients. Fourteen bacteriologically-confirmed MDR typhoid fever cases had jaundice and another 18 cases had an abnormal state of consciousness during admission. Four (2.0%) bacteriologically-confirmed MDR typhoid fever patients died during the period of observation.

Ciprofloxacin for treatment of severe typhoid fever in children.

Eighteen children with bacteriologically confirmed severe typhoid fever were initially treated intravenously with ciprofloxacin (10 mg/kg of body weight per day). Clinical cure with eradication of multiresistant Salmonella typhi infection was observed in 17 patients (94.4%; 95% confidence interval [CI], 84 to 100%). Children regained normal consciousness within an average of 2 days (95% CI, 1.8 to 2.2 days). The temperatures of the children returned to normal within 3.3 days (95% CI, 3.1 to 3.5 days). Complications were not observed during the hospital stay or a 3-month follow-up period. Relapse and carrier state were also not encountered during the follow-up period.

Value of a single Widal test in the diagnosis of typhoid fever.

Results of a single Widal test in patients with bacteriologically confirmed typhoid fever (116), clinically suggestive but culture negative fever (170) and non-typhoidal febrile illness (98) and in normal control children (54) were analysed. Positive Widal test (antibody titre against S. typhi O antigen of 1:160) was recorded in 61.2 per cent of patients with bacteriologically confirmed typhoid fever and in 58.8 per cent with culture negative but clinically suggestive typhoid fever. In contrast, the same titre was observed in 10.2 per cent patients with other febrile illnesses of known etiology and in 1.8 per cent of normal children. Differences in the positivity of Widal test in patients with bacteriologically confirmed typhoid fever and clinically suggestive but culture negative fever were highly significant (P < 0.000001) when compared to that of patients with non-typhoidal febrile illnesses and normal controls. High specificity and positive predictive value in 1:160 dilution makes the Widal test acceptable as a diagnostic tool.

Randomized clinical trial of furazolidone for typhoid fever in children.

The efficacy of furazolidone and chloramphenicol was compared in a randomized trial involving 133 children with bacteriologically confirmed typhoid fever. Sixty-five children were randomized to receive furazolidone, 7.5 mg/kg/day, and 68 children to receive chloramphenicol, 75 mg/kg/day. Both drugs were administered orally. The clinical characteristics of the two treatment groups were comparable on admission. All the strains of Salmonella typhi isolated from the furazolidone group were susceptible to furazolidone. However, of the 68 strains of S. typhi isolated from the chloramphenicol group, 10 were susceptible and 58 were resistant to chloramphenicol. Clinical and bacteriologic cure was observed in 56 (86.2%) children treated with furazolidone and in 35 (51.5%) children given chloramphenicol who were infected with S. typhi strains, irrespective of susceptibility pattern (P = 0.00003). Cure was achieved in 86.2% of furazolidone recipients and 90.0% of chloramphenicol recipients who were infected with strains of S. typhi susceptible to both drugs (P = 0.6). The difference in cure rate was statistically significant (P = 0.000003) when the two treatment groups infected with furazolidone-susceptible but chloramphenicol-resistant strains of S. typhi were compared. There was no relapse or carriers in either of the groups. Furazolidone appears to be a satisfactory alternative to chloramphenicol in the treatment of typhoid fever caused by chloramphenicol-resistant strains of S. typhi.

Prospective study of nosocomial enteric infections in a pediatric hospital, Calcutta.

Hospital acquired enteric infections were investigated by studying 3138 children under 5 years of age who were admitted without diarrhea in nine medical words of a pediatric hospital, Calcutta during the period between March and September 1987. Three hundred and twenty (10.2%) children developed nosocomial diarrhea during their hospital stay. Fecal samples from 178 nosocomial diarrhea, 345 hospitalized diarrhea cases, 178 hospital controls and 200 outpatient controls were collected for detection of established enteropathogens. There were no statistically significant differences in the detection of most of the enteropathogens from fecal samples of nosocomial diarrhea, hospitalized diarrhea and hospital controls. Enteric pathogens were detected at a higher frequency (statistically significant) from fecal samples of nosocomial diarrhea cases as compared to outpatient controls. This study highlights the importance of most of the enteropathogens like Shigella, Salmonella, rotavirus, enteropathogenic E. coli as the cause of hospital cross infection. This study reinforces the importance of developing preventive measures in order to reduce the frequency of illness.