Changing patient population in Dhaka Hospital and Matlab Hospital of icddr,b

Authors


Abstract

The Diarrhoeal Disease Surveillance System of icddr,b noted increasing number of patients ≥60 years at urban Dhaka and rural Matlab from 2001 to 2012. Shigella and Vibrio cholerae were more frequently isolated from elderly people than children under 5 years and adults aged 5–59 in both areas. The resistance observed to various drugs of Shigella in Dhaka and Matlab was trimethoprim–sulphamethoxazole (72–63%), ampicillin (43–55%), nalidixic acid (58–61%), mecillinam (12–9%), azithromycin (13–0%), ciprofloxacin (11–13%) and ceftriaxone (11–0%). Vibrio cholerae isolated in Dhaka and Matlab was resistant to trimethoprim–sulphamethoxazole (98–94%), furazolidone (100%), erythromycin (71–53%), tetracycline (46–44%), ciprofloxacin (3–10%) and azithromycin (3–0%).

Abstract

Le système de surveillance des maladies diarrhéiques du Centre International de Recherche sur les Maladies Diarrhéiques au Bangladesh (CIRMDB) a noté un nombre croissant de patients ≥ 60 ans en zone urbaine à Dhaka et en zone rurale à Matlab de 2001 à 2012. Shigella et Vibrio cholerae ont été plus fréquemment isolés de personnes âgées que d'enfants de moins de 5 ans et des adultes âgés de 5 à 59 dans les deux zones. La résistance observée de Shigella à divers médicaments à Dhaka et à Matlab était la suivante: triméthoprime-sulfaméthoxazole (72% et 63%), ampicilline (43% et 55%), acide nalidixique (58% et 61%), mecillinum (12% et 9%), azithromycine (13% et 0%), ciprofloxacine (11% et 13%) et ceftriaxone (11% et 0%). Pour Vibrio cholerae isolé à Dhaka et Matlab la résistance était la suivante: triméthoprime- sulfaméthoxazole (98% et 94%), furazolidone (100%), érythromycine (71% et 53%), tétracycline (46% et 44%), ciprofloxacine (3% et 10%) et azithromycine (3% et 0%).

Abstract

El sistema de vigilancia de enfermedades diarreicas de icddr,b notó un número creciente de pacientes de ≥60 años en Dhaka urbana y Matlab rural entre el 2001 y 2012. Shigella y Vibrio cholerae eran más frecuentemente aisladas de personas mayores que de niños menores de 5 años y personas con edades entre los 5–59 años en ambas áreas. Los niveles de resistencia observados en Shigella a varios medicamentos en Dhaka y Matlab eran respectivamente de: 72–63% para trimetoprim-sulfametoxazol; 43–55% para ampicilina; 58–61% para ácido nalidíxico; 12–9% para mecilinam; 13–0% para azitromicina; 11–13% para ciprofloxacino y 11–0% para ceftriaxona. Vibrio cholerae aislada en Dhaka y Matlab era resistente a trimetroprim-sulfametoxazol (98–94%), furazolidona (100%), eritromicina (71–53%), tetraciclina (46–44%), ciprofloxacino (3–10%), y azitromicina (3–0%).

Innovations in medical science and evidence-based practices reduced case fatality and increased life expectancy globally (Stewart et al. 2013). This resulted in an increase in the proportions of people older than 60 years – a population with compromised immunity and other regulatory functions and at higher risk of chronic diseases such as diabetes mellitus, cardiorespiratory disorders and cerebrovascular diseases, especially in developing countries (Brown & Flood 2013). The population of Bangladesh, such as other developing countries, is also getting older as the average life expectancy increased from 56 years in 1990 to currently 69 years (Farid et al. 2011).

The International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b) established a Diarrhoeal Disease Surveillance System (DDSS) at its urban Dhaka Hospital in 1979 and rural Matlab Hospital in 2000 (Stoll et al. 1982). The DDSS in Dhaka systematically samples 2% of all patients irrespective of their age, sex, socio-demographic and economic status. The rural Matlab Hospital enrolled all patients coming from icddr,b Health and Demographic Surveillance System (HDSS) area. The DDSS was approved by both the Research Review Committee and the Ethical Review Committee of icddr,b, and verbal consent was provided by the patients or by parents/attending caregivers for minors. These two facilities provide cost-free care and treatment to more than 140 000 and 20 000 patients, respectively, each year (Das et al. 2013). We noted an increasing number of patients 60 years and older at both facilities (Figure 1) and aimed to compare the proportion of patients in different age strata and the pattern of isolation of enteric pathogens among them from 2001 to 2012.

Figure 1.

Number of patients enrolled in Dhaka Hospital and Matlab Hospital in different age strata (2001–2012), Bangladesh.

The DDSS routinely collects clinical, epidemiological and laboratory information from enrolled patients, which include faecal culture for isolation and identification of major enteric pathogens, for example, Shigella, Vibrio cholerae, Campylobacter spp., enterotoxigenic Escherichia coli (ETEC), Entamoeba histolytica, Giardia lamblia and rotavirus. We compared the aetiology of diarrhoea in different age strata: <5, 5–59 and 60 years and older by chi-square test. A probability value of <0.05 was considered statistically significant. The magnitude of association was determined by estimating odds ratios (ORs) and their 95% confidence intervals (CIs).

In Dhaka, the number of elderly patients has increased during the study period. In Matlab, the number of elderly individuals has been increasing over the period with reduced proportion of under-5 children, but there was no change among 5- to 59-year-old adults (Figure 1). The male/female ratio for Dhaka was 1:0.89, and for Matlab, it was 1:0.95. In Dhaka, Shigella was more frequently isolated from elderly than children under-5 [6% vs. 4%; OR – 1.44 (95% CI – 1.11–1.88) P = 0.006] and adults aged 5–59 years [6% vs. 3%; 2.17 (1.64–2.85) <0.001]. Its isolation rate was also higher among rural elderly than children under-5 [13% vs. 9%; 1.42 (1.18–1.70) <0.001] [13% vs. 8%; (1.71 (1.41–2.07) <0.001], respectively. Shigella flexneri was the most often isolated sero group followed by Shigella boydii and Shigella dysenteriae at both sites. Interestingly, Shigella sonnei was only detected in urban elderly.

The isolation rate of Vibrio cholerae was higher among elderly than for under-5 children in Dhaka [20% vs. 9%; 2.56 (2.18–3.00) <0.001] and Matlab [11% vs. 4%; 2.84 (2.32–3.48) <0.001]. However, the rates were higher among the 5–59 year age group in both the areas – [20% vs. 33%; 0.51; (0.44–0.60); p < 0.001] and [11% vs. 17%; 0.59; (0.49–0.71); p < 0.001], respectively. Elderly individuals were less likely to be infected with rotavirus than under-5 children in Dhaka [4% vs. 42%; 0.06 (0.04–0.08) <0.001] and Matlab [3% vs. 33%; 0.06 (0.04–0.08) <0.001]; no difference was noted in the rates of its isolation between elderly and individuals aged 5–59 years. More than 90% of the elderly attended the Dhaka Hospital with some or severe dehydration, compared with 70% in Matlab Hospital [4.27 (3.34–5.45) <0.001]. 55% of the elderly in Dhaka Hospital and 39% in Matlab Hospital required intravenous rehydration at admission [2.00 (1.69–2.36) <0.001]. The overall trend of proportion of diarrhoea episodes attributable to major pathogens is described in Figure 2.

Figure 2.

Trend of yearly distribution of major pathogens in Dhaka and Matlab (2001–2012), Bangladesh.

Of the total isolates of other pathogens, the isolation pattern among elderly in Dhaka and Matlab was Campylobacter spp. (2% vs. 5%), Entamoeba histolytica (4% vs. 11%), Giardia lamblia (2% vs. 5%), respectively, while ETEC for only Dhaka accounted for 4%. All these pathogens were less frequently isolated from elderly individuals than from under-5 children and adults aged 5–59, but were equally isolated from the elderly individuals irrespective of sex.

An estimated 6.05 million people were elderly (60 years of age or older) in 1991, which is expected to rise to 12.05 million in 2015 and 17.62 million in 2025 (U.S. Census Bureau 2010). Unemployment, dependency on family members and relatives, lack of adequate care and food may impose severe adverse health impact on the people of this age group with serious consequences for society and national economy (Low et al. 2013). Our findings capture a particular aspect of change in health characteristics.

The intestinal microflora is influenced by age, for example, reduction in the anaerobes and bifidobacteria and increase in Enterobacter, and reduced intestinal immunity with increased vulnerability to gastrointestinal infections (Hebuterne 2003). Compromised immunity, poor nutrition and inadequate hygienic practices may put the elderly at higher risk for infectious diseases including diarrhoeagenic pathogens. This perhaps has been reflected in our findings of higher prevalence of shigellosis in both urban and rural hospitals compared with individuals in two other age strata. Lower infective dose (10–100 pathogens) and reduced immunity in elderly are likely contributors to the observed higher prevalence of shigellosis among this population. We do not have a ready explanation for the absence of Shigella sonnei in rural Matlab among the elderly.

Rotavirus diarrhoea is considered mainly a disease of childhood; however, 5% and 3% of the elderly in the Dhaka Hospital and Matlab Hospital, respectively, were infected with this pathogen. A higher proportion of elderly from urban area was infected with Vibrio cholerae [20% vs. 11%; 2.10 (1.66–2.65) <0.001], which might be explained by poor hygiene and consumption of contaminated water in urban areas.

Overall, there was no major difference in the antimicrobial resistance patterns of Shigella and Vibrio cholerae in Dhaka and Matlab (Tables 1 and 2). The resistance patterns of Shigella isolates from elderly in Dhaka and Matlab were as follows: trimethoprim–sulphamethoxazole (72% vs. 63%), ampicillin (43% vs. 55%), nalidixic acid (58% vs. 61%), mecillinam (12% vs. 9%), azithromycin (13% vs. 0%), ciprofloxacin (11% vs. 13%) and ceftriaxone (11% vs. 0%). Resistance to these antimicrobials among the other two age groups for Shigella was 55–69% for trimethoprim–sulphamethoxazole, 44–53% for ampicillin, 59–70% for nalidixic acid, 8–12% for mecillinam, 10–23% for azithromycin, 12–16% for ciprofloxacin and 0–1% for ceftriaxone in Dhaka and Matlab. The Vibrio cholerae isolated from the elderly in Dhaka and Matlab was resistant to trimethoprim–sulphamethoxazole (98% vs. 94%), furazolidone (100% vs. 100%), erythromycin (71% vs. 53%), tetracycline (46% vs. 44%), ciprofloxacin (3% vs. 10%) and azithromycin (3% vs. 0%). At least 92% of Vibrio cholerae isolates were resistant to trimethoprim–sulphamethoxazole, 99% to furazolidone, 37% to erythromycin, 33% to tetracycline, 1% to ciprofloxacin and less than 1% to azithromycin from both sites in the other two age groups.

Table 1. Antimicrobial resistance pattern of Shigella in different age strata in Dhaka and Matlab
Age stratum n/N (%)TMP-SXTAMPNALMECAZICIPCEF
  1. AMP, ampicillin; AZI, azithromycin; CEF, ceftriaxone; CIP, ciprofloxacin; MEC, mecillinam; n, resistance isolates; N, total number of isolates; NAL, nalidixic acid; ND, not done; TMP-SXT, trimethoprim–sulphamethoxazole.

Dhaka
<5 years512/739 (69)303/683 (44)337/568 (66)72/648 (11)28/123 (23)115/740 (16)1/136 (1)
5–59 years279/440 (63)166/377 (44)178/304 (59)44/359 (12)8/81 (10)43/440 (14)0/90 (0)
≥60 years54/75 (72)30/72 (42)35/60 (58)9/69 (12)2/15 (13)9/75 (17)2/18 (11)
Matlab
<5 years678/1011 (67)525/995 (53)686/985 (70)75/984 (8)ND117/1000 (12)0/11 (0)
5–59 years269/489 (55)211/475 (44)276/469 (59)36/469 (8)ND58/483 (12)10/1 (0)
≥60 years106/169 (63)91/165 (55)101/165 (61)15/165 (9)ND22/169 (13)
Table 2. Antimicrobial resistance pattern of Vibrio cholerae in different age strata in Dhaka and Matlab
Age stratum n/N (%)TMP-SXTFURERYTETAZICIP
  1. AZI, azithromycin; CIP, ciprofloxacin; ERY, erythromycin; FUR, furazolidone; n, resistance isolates; N, total number of isolates; TET, tetracycline; TMP-SXT, trimethoprim–sulphamethoxazole.

Dhaka
<5 years1413/1446 (98)1046/1047 (100)796/1396 (57)541/1396 (39)1/162 (1)54/1447 (4)
5–59 years4171/4239 (98)2895/2899 (100)2805/4174 (67)1877/4173 (45)1/643 (<1)154/4240 (4)
≥60 years227/232 (98)157/157 (100)165/231 (71)107/231 (46)0/38 (0)7/232 (3)
Matlab
<5 years432/455 (95)371/373 (100)160/437 (37)147/437 (34)0/2 (0)3/452 (1)
5–59 years976/1060 (92)783/786 (100)468/1037 (45)336/1038 (35)0/13 (0)1/1036 (<1)
≥60 years136/145 (94)103/103 (100)75/142 (53)63/142 (44)0/2 (0)0/146 (0)

We noted a major increase in the proportion of patients aged 60 years and older attending icddr,b hospitals both in urban Dhaka and in rural Matlab. This follows the increasing life expectancy and growth of people of this age stratum in Bangladesh. More interestingly, we also noted differences in the aetiology and clinical severity of diarrhoeal diseases among elderly people. We observed a higher proportion of elderly people with some or severe dehydration, and they were frequently infected with Vibrio cholerae. These differences may have implications for the clinical management of the elderly population with diarrhoea attending hospitals in Bangladesh. It is likely that similar changes also take place in the neighbouring countries, which emphasises the requirement of well-designed studies for better management.

Acknowledgements

Hospital surveillance was funded by icddr,b and the Government of the People's Republic of Bangladesh through IHP-HNPRP. icddr,b acknowledges with gratitude the commitment of the Government of the People's Republic of Bangladesh to their research efforts.

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