Serogrupos y susceptibilidad antimicrobiana en cepas de Shigella / Serogroups and antimicrobial susceptibility in Shigella strains

Shigella spp es uno de los agentes causales más importantes de diarrea aguda en los niños. La presente investigación tuvo como objetivo conocer la frecuencia de serogrupos y la susceptibilidad antimicrobiana a los fármacos de elección y a los alternativos. MÉTODOS. Se realizó un estudio descriptivo y retrospectivo entre enero de 2004 y diciembre de 2006 a partir de 34 cepas de Shigella spp. aisladas en heces de niños menores de 5 años ingresados en el Hospital Aleida Fernández Chardiet (Municipio Güines) a causa de enfermedad diarreica aguda. RESULTADOS. Los serogrupos encontrados fueron S sonnei (70,5 por ciento) y S flexneri (29,5 por ciento). Ambos serogrupos mostraron altos niveles de resistencia al trimetoprim-sulfametoxazol y a la ampicilina, ademas en las cepas de S sonnei se encontró resistencia al ácido nalidíxico y en las de S flexneri al cloranfenicol. Todas las cepas mostraron altos porcentajes de sensibilidad a la ceftriaxona, norfloxacina y ciprofloxacina. El 70 por ciento de las cepas de S sonnei fueron multirresistentes. El patrón de multirresistencia (ampicilina, trimetoprim-sulfamtetoxazol y Acido nalidíxico) se encontró en ambos serogrupos. CONCLUSIONES. La determinación y vigilancia de los patrones de resistencia facilita el control de la política de uso de antibióticos en la región estudiada y previene el surgimiento de cepas resistentes a fármacos de nueva generación.

Shigella ssp. is one of the more important causal agents of acute diarrhea in children. Present research has as aim to know serogroups frequency and antimicrobial susceptibility to choice drugs, and to its alternatives. METHODS: A descriptive retrospective study was carried out between January 2004 and December 2006 of 34 strains of Shigella isolated from children lower than 5 years admitted in Aleida Fernßndez Chardiet Hospital in Güines Municipality by acute diarrheic disease. RESULTS: Serogroups included S sonnei (70,5 percent), and S flexeneri (29,5 percent). Both serogroups showed high levels of resistance to Trimethoprim-Sulfamethoxaxole and to Ampicillin and to in strains of S sonnei there was resistance to nalidixic acid, and in that of S flexeneri, to Chloramphenicol. All strains showed high percentages of sensibility to Cephtriaxone, Norphloxacine, and to Cyprophloxacine. The 70 percent of strains of S sonnei were multi-resistant. Multiresistance pattern (Ampicillin, Trimetroprim-Sulfamethoxaxole and nalidixic acid) was present in both serogroups. Assessment and surveillance of resistance patterns allow control of policy on use of antibiotics in study region, and to foresee rise of strains resistant to new generation-drugs.

Prevalence of acute diarrhoea in Kathmandu valley.

This retrospective study was conducted during January to September in the year 1997. Three hundred and forty nine stool samples were collected from diarrhoea patients from different places of Kathmandu valley and examined at National Public Health Laboratory (NPHL), Teku, Kathmandu. Acute diarrhoea becomes epidemic in rainy season and is a major public health problem of the city. In this study, people with poor hygiene practice and poor education were infected more than other people. Among the 349 patients with the gastrointestinal disease, 26.0% were found to have bacterial infection. Out of which, 88 (25.1%), one (0.28%), one (0.28%), and one (0.28%) were found to be Vibrio cholerae 01, Vibrio cholerae 0139, Shigella dysenteriae and Escherichia coli respectively. Cholera cases were found almost throughout the year in the city though the numbers increased during the rainy season. It was highest during July (34.6%) followed by August (32.35%), September 32% and June (6.89%). The uncommon species of Vibrio i.e. Vibrio cholerae 0139 was also found in the study. Higher prevalence was found in urban areas (83.52%) than in rural areas (16.48%). Antimicrobial susceptibility testing of bacterial isolates showed that Ciprofloxacin (97.85%) was found to be the most effective antibiotic followed by Tetracycline (92.34%), Erythromycin (92.34%), Norfloxacin (93.34%), Cholramphenicol, Ampicillim, but Cotrimoxazole were found to be resistant to all isolated Vibrio cholerae.

Risk factors for mortality due to shigellosis: a case-control study among severely-malnourished children in Bangladesh.

To determine the risk factors for death of severely-malnourished Bangladeshi children with shigellosis, a case-control study was conducted at the Clinical Research and Service Centre of ICDDR,B: Centre for Health and Population Research in Dhaka, Bangladesh. One hundred severely-malnourished children (weight-for-age <60% of median of the National Center for Health Statistics), with a positive stool culture for Shigella dysenteriae type 1 or S. flexneri, who died during hospitalization, were compared with another 100 similar children (weight-for-age <60% and with S. dysenteriae type 1 or S. flexneri-associated infection) discharged alive. Children aged less than four years were admitted during December 1993-January 1999. The median age of the cases who died or recovered was 9 months and 12 months respectively. Bronchopneumonia, abdominal distension, absent or sluggish bowel sound, clinical anaemia, altered consciousness, hypothermia, clinical sepsis, low or imperceptible pulse, dehydration, hypoglycaemia, high creatinine, and hyperkalaemia were all significantly more frequent in cases than in controls. In multivariate regression analysis, altered consciousness (odds ratio [OR]=2.6, 95% confidence interval [CI] 1.0-6.8), hypoglycaemia (blood glucose <3 mmol/L (OR=7.8, 95% CI 2.9-19.6), hypothermia (temperature <36 degrees C) (OR=5.7, 95% CI 1.5-22.1), and bronchopneumonia (OR=2.5, 95% CI 1.1-5.5) were identified as significant risk factors for mortality. Severely-malnourished children with shigellosis having hypoglycaemia, hypothermia, altered consciousness and/or bronchopneumonia were at high risk of death. Based on the findings, the study recommends that early diagnosis of shigellosis in severely-malnourished children and assertive therapy for proper management to prevent development of hypothermia, hypoglycaemia, bronchopneumonia, or altered consciousness and its immediate treatment are likely to reduce Shigella-related mortality in severely-malnourished children.

Perceptions of Shigella and of Shigella vaccine among rural Chinese: compatibility with Western models of behavioral change.

Shigella remain a major source of morbidity and mortality in developing countries, including China. In response, national and international researchers are actively working to develop vaccines that will be effective against dysentery and diarrhea caused by shigella dysentariae. With the growing recognition of the problems associated with sustained vaccine acceptance and usage, researchers and policy makers recognize the importance of conducting theory-based qualitative research to inform vaccine development program efforts. Accordingly we undertook this qualitative study involving 81 residents of one of China's rural communities with high rates of dysentery. The semi-structured interviews suggest that a Western model of behavioral change offered a useful research construct. Consistent with the model is the community's strong perception of 'response efficacy' of vaccines, particularly in comparison with water and sanitation and disease treatment. Residents were eager to vaccinate their children despite variable perception of disease severity, while they were less consistent in their interest in vaccinating adults; this enthusiasm for vaccinating children was attributed to China's 'one child per couple' policy. Intervention implications are discussed.

Validation of salmonellosis and shigellosis diagnostic test kits at a provincial hospital in Thailand.

Rapid Diagnosis of salmonellosis and shigellosis was performed using six different diagnostic test kits which recently have been made available commercially. They were Salmo-Dot, Typhi-Dot, Shigel Dot A, B, C, and D test kits for detection of Salmonella spp., group D salmonellae, and groups A, B, C, and D Shigella spp., respectively. The principle of all test kits is a membrane (dot) ELISA using specific monoclonal antibodies to the respective pathogens as the detection reagents. The present study was designed to validate the accuracy of the test kits, at a laboratory in a provincial hospital in Thailand, in comparison with the conventional bacterial culture method alone or with the combined results of the culture and the Western blot analysis (WB) for detecting the respective bacterial lipopolysacchharides (LPS) in specimens. Five hundred rectal swab samples of patients with diarrhea who seeked treatment at the hospital, were evaluated. The diagnostic accuracy of the Salmo-Dot was 91.0% when compared with the conventional bacterial culture method alone but was 100.0% in comparison with the combined results of the culture and the WB. The Typhi-Dot and the Shigel-Dot A, B, C, and D showed 100%, 99.2%, 95.0%, 94.0% and 96.4%, respectively when compared with the culture alone and all were 100% in comparison with the combination of the results of the bacterial culture and the WB. The Shigel-Dot A revealed antigen of type 1 Shigella dysenteriae in several specimens in which the bacteria could not be recovered by the culture method. This difference is important as type 1 Shigella dysenteriae have high epidemic potential and often cause severe morbidity. Unawareness of their presence by the conventional culture may have great impact on disease surveillance for public health. The pathogen detection using the six diagnostic test kits is sensitive, specific, rapid, and relatively simple and less expensive. Several specimens can be tested at the same time without much increase in turn around time. Moreover, these kits produce no contaminated waste as compared with the bacterial culture method. The test kits should be used for rapid screening of specimens of patients with diarrhea especially in areas where culture facilities are inadequate.

Aislamientos de Shigella y Salmonella durante el período 1990-1994 / Isolation of Shigella and Salmonella during the period 1990-1994

En el siguiente trabajo se comunican los aislamientos de Shigella y Salmonela en pacientes con diarreas agudas que fueron atendidos en el Hospital de Niños Ricardo Gutierrez de la ciudad de Santa Fe en el período 1990-1994. Shigella prevaleció en cada uno de los años estudiados con respecto a Salmonella, y el serogrupo predominante fue flexneri. La recuperación de Salmonella fue similar en cada año, debiéndose destacar un brote intrahospitalario a Salmonella typhimurium. Es importante conocer los agentes más frecuentes para que las medidas de control sean dirigidas y permitan orientar investigaciones futuras relacionadas con las enfermedades diarreicas

Shigellosis in children: a prospective hospital based study.

From 1985 to 1988, fecal samples of 950 hospitalized children suffering from diarrhea or dysentery were screened for Shigella species using standard methods. Shigella species were isolated as sole pathogen from 192 (20.2%) cases and S. flexneri type 2 was the predominant serotype. Shigella infection was prevalent throughout the year with high isolation rate during the summer and early monsoon months. Shigella strains isolated during the period were resistant to most of the commonly used drugs for the treatment of shigellosis. Nearly 16% of the Shigella strains were also resistant to nalidixic acid. Presence of blood and mucus in stools (dysentery) was the common clinical presentation of shigellosis cases. Malnutrition was associated with longer duration of illness. High cases fatality rate (16.7%) was observed among hospitalized children infected with Shigella.

Multidrug resistant epidemic shigellosis in a village in west Bengal, 1984.

An out break of acute bacillary dysentery in a village called Dhamasin in Hooghly district of West Bengal was investigated during March 1984. Forty seven percent of families were affected. A total of 91 cases and 2 deaths occurred amongst 937 people giving an over all attack rate of 9.7% and a case fatality rate of 2.2 percent. Highest attack rate (22.7%) was observed in below one year age group. Multiple drug resistant Shigella dysentery type 1 strains were isolated for the first time from 6 out of 22 cases sampled at the domiciliary level. The organism was never isolated earlier during last ten years of surveillance in the infectious Diseases Hospital, Calcutta. Identification of nature of this outbreak and it's causative agent helped to realise the potentiality of extensive spread and paved the way for further investigations. Public health authorities were buffled as the rapid spread of the disease throughout the entire state of West Bengal could not be contained in spite of instituting all probable control measures on war footing.

Clinical & bacteriological profiles of shigellosis in Calcutta before & after an epidemic (1984-87).

Patients below 5 yr of age, hospitalised for shigellosis over a period of four years (1984-87), were studied. During the epidemic of bacillary dysentery (1984) isolation of different Shigella spp. as well as Shigella dysenteriae type 1 was high. Decreased isolation of Sh. dysenteriae type 1 and increased isolation of Sh. flexneri was observed during post-epidemic years (1985-87). Isolation of different Shigella spp. was always above 25 per cent from patients with dysentery and greater than 7 per cent from those with watery diarrhoea during the post-epidemic years. Higher incidence of shigellosis was observed amongst older children (greater than 3 yr). Most of the shigellosis patients complained of blood and mucus in stools. Vomiting was common among shigellosis patients presenting with watery diarrhoea whereas fever was commonly seen in patients with both dysentery and watery diarrhoea. Most patients of shigellosis presenting with blood and mucus in stools had no dehydration.

Hemolytic uremic syndrome associated with shigellosis: report of two cases.

Two patients with hemolytic uremic syndrome admitted to Udornthani Hospital, Thailand, were reported. The preceding illness was shigellosis. The stool culture was positive for Shigella dysenteriae in one patient and Shigella flexneri in another. The management was successful with peritoneal dialysis in one and symptomatic treatment in another. Both patients had complete recovery.

Frecuencia etiológica de la shigelosis por especie y serotipo en Venezuela / Etiological frequency for species and serotypes of Shigella in Venezuela

Se determina la frecuencia etiológica por especie y por serotipo de 1369 cepas de Shigella aisladas durante el período 1968-1982 de coprocultivos procedentes principalmente de niños con clínica de disentería bacilar. De ellas, 870 (63.55%) son Shigella flexneri y 414 (30.24%) son Shigella sonnei. El predominio de Shigella flexneri se hace en base a los serotipos B2, B1, B3 y B6. Un incremento en los aislamientos de Shigella sonnei ocurre en el transcurso del estudio. A Shigella dysenteriae corresponden 77 (5.62%) cepas, 15 (19.48%) de ellas son Shigella dysenteriae A1 ocurriendo el último aislamiento de este serotipo en 1975. Shigella dysenteriae A2 se ha hecho endémico en la región y es responsable en los últimos 8 años del 96.6% de los aislamientos de Shigella dysenteriae. Shigella boydii es infrecuentemente aislada en nuestro medio (0.58%)