Dengue infection in Dhaka City, Bangladesh.

Dengue fever (DF) and dengue haemorrhagic fever (DHF) are now endemic in Bangladesh with outbreaks being reported quite frequently. This cross sectional study was done clinically suspected dengue patients were selected from different hospitals of Dhaka city, Bangladesh, from January 2008 to December 2008. The clinical features, risk factors and laboratory findings associated with dengue infection were investigated among 201 clinically suspected patients. Antibodies were detected in 137(68.2%) cases. Of these, 80(58.4%) were primary and 57(41.6%) as secondary dengue cases according to presence of dengue-specific IgM and/or IgG antibodies. Among primary cases, 70(87.5%) were DF and 10(12.5%) were DHF cases, in contrast to secondary cases, where 10(18.1%) were DF and 47(81.9%) were DHF cases. Majority (57.9%) of patients presented with Grade I and 42.1% had Grade II disease. Patients between 16-30 years were the most vulnerable age group (81.3% DF and 71.9% DHF patients). Males out-numbered females with 72.5% male vs. 27.5% female patients having DF and 68.4% male vs. 31.6% female patients having DHF. The monsoon period was the peak season for dengue infection. Headache and arthralgia were the most frequent symptoms in both DF and DHF, but vomiting was more common in DHF. The Tourniquet test was significantly positive among DHF than DF cases (p = 0.001). Platelet count was the only laboratory parameter that showed significantly higher values among DHF than DF cases (p = 0.001).

Evaluation of a typhoid/paratyphoid diagnostic assay (TPTest) detecting anti-Salmonella IgA in secretions of peripheral blood lymphocytes in patients in Dhaka, Bangladesh.

BACKGROUND: Rapid and reliable diagnostic assays for enteric (typhoid and paratyphoid) fever are urgently needed. We report the characterization of novel approach utilizing lymphocyte secretions, for diagnosing patients with enteric fever by the TPTest procedure. METHODOLOGY: TPTest detects Salmonella-specific IgA responses in lymphocyte culture supernatant. We utilized TPTest in patients with suspected enteric fever, patients with other illnesses, and healthy controls. We also evaluated simplified modifications of TPTest for adaptation in laboratories with limited facilities and equipment. PRINCIPAL FINDINGS: TPTest was positive in 39 (27 typhoid and 12 paratyphoid A) patients confirmed by blood culture and was negative in 74 healthy individuals. Among 32 individuals with other illnesses, 29 were negative by TPTest. Of 204 individuals with suspected enteric fever who were negative by blood culture, 44 were positive by TPTest and the patients were clinically indistinguishable from patients with confirmed bacteremia, except they were more likely to be under 5 years of age. We evaluated simplifications in TPTest, including showing that lymphocytes could be recovered using lysis buffer or buffy coat method as opposed to centrifugation, that incubation of cells at 37°C did not require supplemental CO2, and that results were available for majority of samples within 24 hours. Positive results by TPTest are transient and revert to negative during convalescence, supporting use of the test in endemic areas. The results can also be read using immunodot blot approach as opposed to ELISA. Since no true gold standard currently exists, we used a number of definitions of true positives and negatives. TPTest had sensitivity of 100% compared to blood culture, and specificity that ranged from 78-97% (73-100, 95% CI), depending on definition of true negative. CONCLUSION: The TPTest is useful for identification of patients with enteric fever in an endemic area, and additional development of simplified TPTest is warranted.

Antimicrobial susceptibility pattern of extended spectrum beta-lactamase producing gram-negative bacteria isolated from wound and urine in a tertiary care hospital, Dhaka City, Bangladesh.

From a total of 320 bacterial samples from wound swab and urine 169 (53%) gram-negative bacteria were isolated, of which 42 (25%) extended-spectrum beta-lactamase (ESBL) producers were detected by double-disk synergy test. ESBL producers were significantly more resistant against amoxiclav, Co-trimoxazole, ciprofloxacin, amikacin and gentamicin than non-ESBL producers. Among the 42 ESBL producers, 76% were positive for blaCTX-M and 43% were positive for blaOXA, with blaCTX-M predominantly (97%) observed in E. coli and blaOXA predominantly (80%) in Pseudomonas spp. Class 1 integron was found in 75% of blaCTX-M positive and 56% of blaOXA positive strains. Combinations of ESBL genes and class 1 integron were observed in 29 (69%) of the ESBL producers. The findings of this study infer that CTX-M and OXA producers are emerging in Bangladesh and we report the presence of blaOXA for the first time in Bangladesh.

A survey of antimicrobial prescribing and dispensing practices in rural Bangladesh.

This study was undertaken to determine the patterns of antimicrobial prescription by 64 Rural Medical Practitioners (RMPs) from Bangladesh. The antimicrobial dispensing procedures followed by the local retail drug sellers along with the purchasing capacities of the patients was also assessed. All antimicrobial agents were prescribed mainly on the patient's complaints, and all available antibiotics were prescribed in inappropriate doses and duration. In most cases, the RMPs initiated treatment with a parenteral form of antibiotic, and a different oral antibiotic usually followed. Parenteral streptomycin was used most frequently in short inadequate courses. Almost half of the antibiotics were sold without any prescriptions, and even ordinary people without any knowledge of medicine asked the drug seller for specific antibiotics. This unregulated prescribing and dispensing practice has the potential risk for the development and spread of antimicrobial resistance on a global scale.

Emergence of methicilllin resistant Staphylococcus aureus (MRSA) associated with wound infections.

In a hospital setting antimicrobial resistant organisms especially Methicillin resistant Staphylococcus aureus (MRSA) has emerged as an important variable influencing patients' outcome and overall resource utilisation. The present study was undertaken to find out the proportion of MRSA and other organisms and their antimicrobial resistance pattern in admitted cases with postoperative wound infections. A total of 50 wound swabs were collected irrespective of age and sex of the patients from National Institute of Traumatology and Orthopaedics Rehabilitation (NITOR). The laboratory work was performed in the department of microbiology of National Institute of Cardiovascular Diseases (NICVD). Isolation, identification and susceptibility testing was done according to the guideline of the National Committee for Clinical Laboratory Standards (NCCLS, 1998). Out of the 50 samples 34 yielded growths of which 15 had growth of single organism and 19 had mixed growth of 2 to 3 organisms. Four different types of organisms were identified. Highest percentage was Escherichia coli 55.9%, followed by Pseudomonas sp. 52.9%, Proteus sp. 38.2%, and Staphylococcus aureus 17.6%. Of the 6 isolates of S aureus 5 (83.3%) were MRSA. Therefore it can be concluded that MRSA is existing in the hospital premises of NITOR, which can endanger the life of many. This study emphasises that susceptibility testing of all clinical isolates is essential to reduce the morbidity, mortality and longer duration of hospital stay. In addition proper management of the cases can decrease the spread of multiple drug resistant organisms in the community.

Molecular analysis of multi-drug resistant Salmonella typhi from urban paediatric population of Bangladesh.

The prevalence and genetic basis of resistance of multi-drug resistant (MDR) S typhi strains from an urban paediatric population was determined. Blood cultures performed on 109 cases of suspected typhoid fever yielded 30(27.5%) S typhi isolates. Of these, 20(67%) S typhi isolates were resistant to the common antimicrobials used in Bangladesh, eg, chloramphenicol, ampicillin, cotrimoxazole, streptomycin and tetracycline, while 6(20%) isolates were resistant only to streptomycin. However, all the isolates were sensitive to fluquinolones and cephalosporins. Molecular analysis demonstrated that all MDR strains possessed a single large transferable 98 MDal plasmid. On conjugation, chloramphenicol, ampicillin and cotrimoxazole resistance was transferred from MDR strains to E coli K-12. Restriction endonuclease analysis of plasmid DNA showed similar digest profiles of all 5 selected donors and their transconjugants. This trend of increasing resistant strains of S typhi, especially by the transferable plasmid is of major public health concern.

Analysis of plasmid and chromosomal DNA of multidrug-resistant Salmonella enterica serovar typhi from Asia.

Molecular analysis of chromosomal DNA from 193 multidrug-resistant (MDR) Salmonella enterica serovar Typhi isolates from 1990 to 1995 from Pakistan, Kuwait, Malaysia, Bangladesh, and India produced a total of five major different pulsed-field gel electrophoresis (PFGE) patterns. Even within a particular country MDR S. enterica serovar Typhi DNA was found to be in different PFGE groups. Similar self-transferable 98-MDa plasmids belonging to either incompatibility group incHI1 or incHI1/FIIA were implicated in the MDR phenotype in S. enterica serovar Typhi isolates from all the locations except Quetta, Pakistan, where the majority were of incFIA. A total of five different PFGE genotypes with six different plasmids, based on incompatibility and restriction endonuclease analysis groups, were found among these MDR S. enterica serovar Typhi isolates.

Immunofluorescent microscopic findings in glomerulonephritis.

Histopathology and direct immunofluorescence (DIF) microscopy were performed on renal biopsy specimens of 60 clinically suspected cases of glomerulonephritis (GN). Histopathological diagnosis was obtained in 44 (73.3%) cases and immune complex deposition were detected by DIF in 28 (46.7%) cases. Immune complex deposition were observed in all cases of membranous GN, systemic lupus erythematosus (SLE), and rapidly progressive GN (RPGN), most of the cases of diffuse proliferative GN (2 out of 3) mesangioproliferative GN (12 out of 15) and focal glomeruloscleros is (3 out of 5 cases). No immune deposits were observed in minimal change GN, chronic GN, and diabetic nephropathy. Histopathological diagnosis was not obtained in 16 (26.7%) cases, 3 (5%) of which showed immune complex deposition by DIF. Anti-GBM nephritis was demonstrated in one (3.6%) case, the rest were immune complex nephritis.

Antimicrobial susceptibility of Shigella from a rural community in Bangladesh.

Of the 63 Shigella strains isolated from stool cultures from 200 patients who attended a district hospital in Bangladesh with bloody diarrhoea, 37 (59%) were S. dysenteriae type 1, 25 (39%) were S. flexneri and only one (2%) was S. sonnei. Over half (54%) of the Shigella isolates came from children aged < 10 years. Most (89%) of the isolates of S. dysenteriae type 1 were resistant to ampicillin, cotrimoxazole, nalidixic acid, tetracycline and chloramphenicol. Although many (60%) of the isolates of S. flexneri were resistant to ampicillin and cotrimoxazole, only 4% of them were resistant to nalidixic acid. However, all of the S. dysenteriae and S. flexneri were sensitive to ciprofloxacin. The need for periodic monitoring to determine the resistance pattern in remote areas is emphasised.

Water sources and environmental transmission of multiply resistant enteric bacteria in rural Bangladesh.

The role of different water sources in the spread of multiply resistant enteric bacteria was investigated in rural Bangladesh. The prevalence of resistance to commonly used antimicrobial agents in the faecal flora of village children and the water quality and prevalence of resistance in village water sources were studied. Most of the children studied (81%) had multiply resistant faecal coliform bacteria, i.e. bacteria resistant to at least three antimicrobials. Although tubewells provided water with low faecal coliform counts, 62% of household storage pots contained water with moderate to high counts. Most of the storage pots (76%) and each of the river and pond sites tested contained multiply resistant isolates. Contamination of water within the household, and the widespread distribution of resistant coliforms in the environment, contribute to the high prevalence of multiply resistant enteric flora in the community. These findings are of importance in understanding the spread of multiply resistant enteric pathogens.

The prevalence and genetics of resistance to commonly used antimicrobial agents in faecal Enterobacteriaceae from children in Bangladesh.

The present study was undertaken to investigate the occurrence of antibiotic resistance in enteric flora in 64 children in rural Bangladesh over a 12-month period. The antibiotic resistance pattern of the isolates varied throughout the year and multiple resistance was highest during the post monsoon period. Seventy-three percent of children had isolates resistant to more than three antibiotics throughout the year. Resistance to streptomycin was highest (78%), followed closely by ampicillin (72%). Of 82 multiply resistant isolates, plasmid DNA was demonstrated in 75%. Plasmid sizes ranged between 3.7 and 110 MDa, the commonest plasmids were of 70, 98 and 110 MDa. Complete or partial resistance was transferred by conjugation from 52% of the isolates, most frequently by single plasmids. The commonest plasmid incompatibility group was F11-A (46%) followed by incompatibility group P (22%). Plasmids of molecular weight 98 MDa most often hybridized with F11-A probes and those of 110 MDa with H11 probes. Plasmids from 10 transconjugants were digested with restriction enzymes and digest patterns demonstrated the presence of common plasmids. The findings show that there is a diverse, and mobile, genetic pool of resistance genes in this rural community. This genetic reservoir is potentially transferable to enteric pathogens, with major implications for public health and diarrhoeal disease control.