Biomedical subjects

S D Puthucheary

Publications and source records attributed to S D Puthucheary.

At least 37 records · Page 2Linked to original sources

PubMed2002

Genetic diversity of clinical and environmental strains of Salmonella enterica serotype Weltevreden isolated in Malaysia.

The incidence of food-borne salmonellosis due to Salmonella enterica serotype Weltevreden is reported to be on the increase in Malaysia. The pulsed-field gel electrophoresis (PFGE) subtyping method was used to assess the extent of genetic diversity and clonality of Salmonella serotype Weltevreden strains from humans and the environment. PFGE of XbaI-digested chromosomal DNA from 95 strains of Salmonella serotype Weltevreden gave 39 distinct profiles with a wide range of Dice coefficients (0.27 to 1.00), indicating that PFGE is very discriminative and that multiple clones of Salmonella serotype Weltevreden exist among clinical and environmental isolates. Strains of one dominant pulsotype (pulsotype X1/X2) appeared to be endemic in this region, as they were consistently recovered from humans with salmonellosis between 1996 and 2001 and from raw vegetables. In addition, the sharing of similar PFGE profiles among isolates from humans, vegetables, and beef provides indirect evidence of the possible transmission of salmonellosis from contaminated raw vegetables and meat to humans. Furthermore, the recurrence of PFGE profile X21 among isolates found in samples of vegetables from one wet market indicated the persistence of this clone. The environment in the wet markets may represent a major source of cross-contamination of vegetables with Salmonella serotype Weltevreden. Antibiotic sensitivity tests showed that the clinical isolates of Salmonella serotype Weltevreden remained drug sensitive but that the vegetable isolates were resistant to at least two antibiotics. To the best of our knowledge, this is the first study to compare clinical and environmental isolates of Salmonella serotype Weltevreden in Malaysia.

DNA, Bacterial↗

PubMed2002

Bacterial enteropathogens isolated in childhood diarrhoea in Kuala Lumpur--the changing trend.

A retrospective review of all stool samples obtained from children aged < 16 years with diarrhoea from University of Malaya Medical Centre (UMMC), Kuala Lumpur, from 1978 to 1997 was undertaken to ascertain the pattern of bacterial pathogens causing diarrhoea in children in an urban area in Malaysia. Of 26444 stool samples processed, 2989 (11%) were positive. The five most common bacterial pathogens isolated were non-typhoidal Salmonella (57%), enteropathogenic E. coli (EPEC) (14%), Shigella spp. (11%), Campylobacter spp. (5%) and Aeromonas spp. (4%). There was a significant reduction in the average percentage of positive isolation during the last 5 years of the study period as compared to the first 5 years (15.0% vs. 7.2%; r = -0.92, p = 0.0001). EPEC and Shigella spp. were less commonly isolated in the last five years compared with the first five years of the study (6% vs 21% p < 0.001 for E. coli; 7% vs 22%, p < 0.001 for Shigella spp.). This information is important for public health education in reducing the incidence of childhood diarrhoea further, and in the selection of appropriate antimicrobials in the management of extra-intestinal complications of childhood diarrhoea.

Academic Medical Centers↗

PubMed2001

Detection of immunoglobulins M and G using culture filtrate antigen of Burkholderia pseudomallei.

IgM and IgG based ELISA systems were developed using the culture filtrate antigen (CFA) of Burkholderia pseudomallei. The assays were evaluated using 95 sera from 66 septicemic cases and 47 sera from 20 cases with localized melioidosis. In addition 65 sera from culture negative cases that were also serologically negative for other endemic infections clinically suspected of melioidosis were included. These were compared with sera from 260 non-melioidosis cases, 169 sera from individuals with high risk of acquiring the infection and 48 sera from healthy controls. The IgG-ELISA was 96% sensitive and 94% specific. All sera from cases with septicemic and localized infections and 61 of 63 sera from clinically suspected melioidosis cases were positive for IgG antibody. The geometric mean titre index (GMTI) values of IgG antibody in melioidosis cases were significantly higher (p < 0.0005) compared to that of healthy subjects, high risk group and subjects with non-melioidosis infections. The sensitivity and specificity of IgM ELISA was 74 and 99% respectively. The GMTI value of IgM antibody in the sera of melioidosis cases was significantly higher as compared to that of non-melioidosis disease controls (p < or = 0.001). These results demonstrate that the detection of IgG is a better indicator of the disease in the diagnosis of melioidosis.

Antibodies, Bacterial↗

PubMed2001

Distribution of immunoglobulin classes and IgG subclasses against a culture filtrate antigen of Burkholderia pseudomallei in melioidosis patients.

The class and subclass distribution of antibody response to the culture filtrate antigen (CFA) of Burkholderia pseudomallei was examined in the sera of 45 septicaemic and 17 localised melioidosis cases and 40 cases clinically suspected of melioidosis and the results were compared with those from high-risk and healthy control groups. The geometric mean titre index (GMTI) values for all classes and subclasses of immunoglobulins examined were higher for sera from the proven and clinically suspected melioidosis cases than for the control groups. However, the highest response in the three patient groups was that of IgG with GMTIs ranging from 219.4 to 291.6 and the lowest was for IgM with GMTIs of 22.5, 24.3 and 28.7. The IgA response was intermediate with GMTIs ranging from 119.2 to 170. The GMTIs were highest for IgG in septicaemic and localised infections and for IgA and IgM in localised infections. As regards IgG subclass distribution, IgG1 and IgG2 were the predominant subclasses produced against the CFA in contrast to IgG3 and IgG4, which were produced in low amounts. None of the sera from the control groups had any significant titres of antibodies.

Antibodies, Bacterial↗

PubMed2001

Retrospective study of Aeromonas infection in a Malaysian urban area: a 10-year experience.

AIMS: To describe the patterns of isolation of Aeromonas spp. and the resulting spectrum of infection, intestinal and extra-intestinal,from infants and children in an urban area in a hot and humid country from SoutheastAsia. MATERIALS AND METHODS: Retrospective review of all bacterial culture records from children below 16 years of age, from the Department of Medical Microbiology, University of Malaya Medical Centre, Kuala Lumpur, from January 1988 to December 1997. Review of all stool samples and rectal swabs obtained from children during the same period were carried out to ascertain the isolation rate of Aeromonas sp. from stools and rectal swabs. The case records of those with a positive Aeromonas culture were retrieved and reviewed. RESULTS: During the study period, 84 culture samples were positive of Aeromonas spp. (stools 48, rectal swabs 36). During the same period, 1,352 stool samples were positive for at least one enteropathogen. Aeromonas spp. constituted 0.62% of all stool samples. Of the 61 cases reviewed,four patterns of colonization were observed: (a) 17 cases of mostly asymptomatic nursery newborns with a positive rectal swab; (b) 9 children with no diarrhoea; (c) 23 cases, of who seven were immunocompromised, had acute, brief watery diarrhoea without severe dehydration or disturbances of serum electrolytes. No chronic diarrhoea or bacteraemia was noted. (d) 12 cases had a mixed infection with a second enteropathogen isolated from stool samples. Three had chronic diarrhoea No extra-intestinal infection attributed to Aeromonas spp. was identified in this study. CONCLUSION: Aeromonas was a rare cause of gastroenteritis in urban Malaysian children. It was isolated almost exclusively from gastro-intestinal tract, caused mostly by mild gastroenteritis with no serious complications. Asymptomatic stool carriage among newborns admitted to special care nursery and older children with no diarrhoea were observed.

Academic Medical Centers↗

PubMed2001

Acute respiratory failure in melioidosis.

BACKGROUND: In melioidosis caused by Burkholderia pseudomallei, although every organ in the body may be involved, the highest mortality of 73% occurs when the respiratory system is affected. These patients invariably die of acute respiratory failure. Most of them also have underlying predisposing factors like diabetes mellitus. AIM OF STUDY: A retrospective study of six such cases was carried out in order to elicit the possible causes and mechanisms of acute respiratory failure in patients with melioidosis. METHOD: Patients' records were reviewed for demographic, clinical, laboratory, radiological and histopathological data. RESULTS: The rapidity of onset of respiratory failure was remarkable and was accompanied by relentless hypoxaemia that was refractory to treatment despite the application of high positive end expiratory pressure and other supportive measures. All had bilateral opacities on frontal chest radiographs, focal and diffuse necrotizing pneumonia and presence of hyaline membranes in lung tissues seen histologically, supporting the accepted criteria for ALI/ARDS. CONCLUSION: Patients with sepsis due to B. pseudomallei develop ALI/ARDS very rapidly resulting in high mortality rates. Possible mechanisms involved are discussed. Awareness of the disease in endemic areas, the development of rapid diagnostic methods and appropriate management procedures are urgently needed for the prevention of ARDS and subsequent reduction in mortality in such cases.

Acute Disease↗

PubMed2000

Molecular evidence of clonality amongst Vibrio cholerae O1 biotype El Tor during an outbreak in Malaysia.

Forty-three clinical strains of V. cholerae O1 biotype E1 Tor were isolated between 3 May and 10 June 1998 during an outbreak in the metropolitan area of Kuala Lumpur and its suburbs. With the exception of three Inaba strains that were restricted to three members of a family, all the others belonged to the Ogawa serotype. The strains were analysed for clonality using ribotyping and pulsed-field gel electrophoresis (PFGE). Two ribotypes, V/B21a and B27, were identified among 40 Ogawa isolates using BglI restriction endonuclease. Ribotype V/B21a has been described previously from Taiwan and Colombia and several Asian countries while B27 has been reported among isolates from Senegal. The three Inaba strains belonged to one ribotype, designated type A, not previously reported. PFGE analysis using NotI revealed that all isolates within a ribotype had identical profiles demonstrating clonality amongst the strains. Dice coefficient analysis of the two Ogawa genotypes revealed 89% similarity on ribotype patterns and 91.3% on PFGE profiles. Ribotype V/B21a isolates were associated with cases from dispersed areas of Kuala Lumpur and its suburbs while ribotype B27 was restricted to cases from one particular area suggesting a common-source outbreak.

Bacterial Typing Techniques↗

PubMed2000

Detection of virulence associated genes, haemolysin and protease amongst Vibrio cholerae isolated in Malaysia.

Eighty-four strains of Vibrio cholerae O1, O139 and non-O1/non-O139 from clinical and environmental sources were investigated for the presence of the toxin co-regulated pilus gene, tcpA, the virulence cassette genes ctxA, zot, ace and cep and also for their ability to elaborate haemolysin and protease. The ctxA and zot genes were detected using DNA-DNA hybridization while the ace, cep and tcpA genes were detected using PCR. Production of haemolysin and protease was detected using mammalian erythrocytes and an agar diffusion assay respectively. Analysis of their virulence profiles showed six different groups designated Type I to Type VI and the major distinguishing factor among these profiles was in the in vitro production of haemolysin and/or protease. Clinical O1, O139 and environmental O1 strains were similar with regard to presence of the virulence cassette genes. All environmental O1 strains with the exception of one were found to possess ctxA, zot and ace giving rise to the probability that these strains may actually be of clinical origin. One strain which had only cep but none of the toxin genes may be a true environmental isolate. The virulence cassette and colonization factor genes were absent in all non-O1/non-O139 environmental strains but production of both the haemolysin and protease was present, indicating that these may be putative virulence factors. These findings suggest that with regard to its pathogenic potential, only strains of the O1 and O139 serogroup that possess the tcpA gene which encodes the phage receptor, have the potential to acquire the CTX genetic element and become choleragenic.

Cholera↗

PubMed2000

Extra-intestinal non-typhoidal Salmonella infections in children.

Extra-intestinal non-typhoidal Salmonella (NTS) infections are uncommon in developed countries but common in developing ones. The risk factors, clinical features and outcome of children admitted to the Department of Paediatrics, University of Malaya Medical Center, Kuala Lumpur from 1978 to 1998 with extra-intestinal NTS infections were reviewed. All positive cultures of NTS, blood, cerebrospinal fluid, urine, synovial, pericardial and other body secretions (except stools), were included. Of the 98 cases reviewed, 56 were boys and 42 girls. The mean age was 2.1 years (range: newborn to 14 years). Twenty-seven children were severely immunocompromised and 21 had underlying chronic medical disorders. Bacteraemia was the most commonly detected type of infection and meningitis the commonest focal infection. The overall mortality rate was 15%. An immunocompromised state or underlying chronic medical disorder was associated with increased mortality. The three serotypes most commonly isolated were S. enteritidis, S. paratyphi B and S. typhimurium. Most isolates were sensitive to antibiotics commonly used in salmonellosis.

Adolescent↗

PubMed2000

Evaluation of a new commercially available immunoglobulin M and immunoglobulin G immunochromatographic test for diagnosis of melioidosis infection.

An immunochromatographic test for the rapid determination of immunoglobulin M (IgM) and IgG antibodies to Burkholderia pseudomallei was evaluated by using sera from bacteriologically confirmed melioidosis patients and high-risk and clinically suspected patients, along with disease control groups. The sensitivities were 100 and 93% for the IgG and IgM tests, respectively, while the specificity was 95% for both assays. The test was rapid and simple to perform, with results obtained in 10 min.

Antibodies, Bacterial↗

PubMed2000

Diagnostic and prognostic value of an immunofluorescent assay for melioidosis.

Melioidosis caused by Burkholderia pseudomallei is endemic in southeast Asia. The clinical manifestations range from wound infections to acute septicemia. In some cases, recurrence can also occur following complete recovery. Case fatality rates are high and a major factor is the delay in the culture and identification of the bacterium. An immunofluorescent assay (IFAT) using whole-cell antigen for the detection of total antibodies to B. pseudomallei was tested with 650 sera. Using a cut-off value of 1:80, 66 sera from culture-confirmed cases were positive with titers > or = 320. In another 523 sera from patients in which no other etiology could be found, 149 (23.4%) were positive. To monitor disease activity, persistence of antibody levels was investigated on 61 serial sera samples collected from 14 other confirmed cases on follow-up visits while on oral maintenance therapy. The IFAT demonstrated a reduction in titers in cases of localized infections, suggesting that either the infection was being resolved or arrested while septicemic patients maintained high IFAT titers on follow-up, suggesting the possibility of continuous sequestration of antigen from an intracellular source.

Adolescent↗

PubMed2000

Application of ribosomal RNA gene restriction patterns analysis and pulsed-field gel electrophoresis in distinguishing Salmonella weltevreden isolates in Malaysia.

A representative sample of 20 isolates of Salmonella weltevreden strains from stool cultures of patients admitted at the University Hospital, Kuala Lumpur, Malaysia were analyzed. All the strains were susceptible to ampicillin, ceftriaxone, ciprofloxacin, chloramphenicol, tetracycline, trimethoprim, gentamicin and co-trimoxazole. Ribosomal RNA gene restriction pattern analysis of PstI-digested DNA gave three ribotypes while pulsed-field gel electrophoresis (PFGE) analysis of XbaI-digested DNA gave ten distinct profiles. PFGE was more discriminative than ribotyping in distinguishing the strains. The majority of the strains analyzed were very closely related with similarity coefficient values ranging from 0.8 to 1.0. Both PFGE and ribotyping could distinguish one of the strains which was obtained from a patient following a bone marrow transplant for beta-thalassemia major, indicating that this particular strain was unrelated to the rest of the strains from patients with acute gastroenteritis.

Base Sequence↗

PubMed1999

Salmonella meningitis and its complications in infants.

OBJECTIVE: To review the presenting features, complications and outcome of infants with Salmonella meningitis. METHODOLOGY: Retrospective review of all cultures of cerebrospinal fluid positive for bacteria in children below 12 years of age, processed at the Department of Medical Microbiology, University of Malaya Medical Centre, Kuala Lumpur from 1973 to 1997. Records of all cases positive for Salmonella species were retrieved and studied. RESULTS: Thirteen infants aged 3 days to 9 months with Salmonella meningitis were included. The median age of onset of symptoms was 4 months. The clinical and laboratory features were similar to other causes of bacterial meningitis. Salmonella enteritidis was the commonest serotype isolated. Nine infants developed fits, six of which were difficult to control. Other complications noted were hydrocephalus (five), subdural effusions (four), empyema (three), ventriculitis (two), intracranial haemorrhage and cerebral abscess (one each). The use of ampicillin and/or chloramphenicol and inadequate duration of therapy resulted in recrudescence or relapse in five infants. The overall mortality was 18%. The presence of empyema, intracerebral abscess, ventriculitis, hydrocephalus, and intracranial haemorrhage were associated with adverse neurodevelopmental sequelae or death. More than half of those who survived had normal long-term outcome. CONCLUSION: Infants who developed neurological complications as a result of Salmonella meningitis had significant mortality and adverse long-term neurodevelopment outcome.

Anti-Bacterial Agents↗

PubMed1998

Stability of strain genotypes of Burkholderia pseudomallei from patients with single and recurrent episodes of melioidosis.

The constancy of strain genotypes of multiple isolates of Burkholderia pseudomallei from 13 patients with melioidosis was examined by BamHI ribotyping and pulsed-field gel electrophoresis (PFGE) of XbaI digests of DNA. Seven of 8 patients with single episodes of melioidosis each yielded genetically identical isolates and only one of five patients with recurrent episodes was infected with a new strain clearly distinct from the original primary strain. Variation was observed in PFGE patterns of primary and relapse isolates of another patient but this was insufficient to define genetically distinct strains. We conclude that most patients with single or multiple episodes of melioidosis retain a single strain.

Burkholderia pseudomallei↗

PubMed1998

Non-typhoid Salmonella gastroenteritis.

OBJECTIVE: To study the clinical features of non-typhoid Salmonella gastroenteritis and the incidence, risk factors and outcome of invasive complications in urban Malaysian children. To describe the serotypes of Salmonella species isolated and the pattern of antibiotic susceptibility. METHODOLOGY: Retrospective review of a group of 131 children with non-typhoid Salmonella gastroenteritis seen at the University Hospital, Kuala Lumpur, Malaysia from January 1994 to December 1996. RESULTS: Sixty-seven percent were infants below one year of age. Fever and vomiting were seen in nearly half of children. Seven children (5.3%) had invasive complications: 5 bacteraemia and 2 meningitis. Age below 6 months, fever > 38.0 degrees C, and dehydration on admission were significantly associated with invasive complications. The commonest serotypes isolated were S. enteritidis, S. paratyphi B, and S. bovis-morbificans. A total of 94-100% of isolates were susceptible to commonly prescribed antibiotics. CONCLUSIONS: Children with Salmonella gastroenteritis below 6 months of age who are febrile and dehydrated should be treated empirically with antibiotics until the result of blood culture is available.

Adolescent↗

PubMed1998

Antigenic differences between clinical and environmental isolates of Burkholderia pseudomallei.

Burkholderia pseudomallei is a free-living organism that causes the potentially lethal tropical infection melioidosis. The disease is endemic in many parts of eastern Asia and northern Australia. The presence of two distinct biotypes in soil can be reliably distinguished by their ability to assimilate L-arabinose. Whereas some soil isolates could utilize this substrate (Ara+), the remaining soil isolates and all clinical isolates tested so far could not (Ara-). Only the Ara- isolates were virulent in animal models. We have raised a murine monoclonal antibody (MAb) that can readily distinguish Ara- from Ara+ biotypes. The MAb reacted with a high molecular weight component present only on the Ara- biotype. With this MAb, clinical and soil Ara- isolates gave identical positive reactions in agglutination, immunofluorescence, ELISA and immunoblot assays. Using these same assay systems, the soil Ara+ biotype did not react with the MAb. Similar but distinct immunoblot patterns were also noted when these two Ara biotypes were probed with sera from patients with melioidosis or with polyclonal immune rabbit sera. These data showed that the Ara- biotype from both clinical and environmental isolates is antigenically different from its Ara+ environmental counterpart. The SDS-PAGE protein and lectin-binding profiles of both groups of Ara- isolates were also found to be different from those of the Ara+ biotype.

Animals↗

PubMed1998

Typhoid fever in children--a retrospective study of 54 cases from Malaysia.

BACKGROUND/AIM OF STUDY: Typhoid fever, which is endemic in Malaysia, affects all age groups and it has been stated that classical features described in textbooks were absent in children. The aim of this study was to find out whether this was true in the local setting and hence a retrospective study was undertaken. METHODS: Fifty-four paediatric patients satisfied the inclusion criteria and all were seen consecutively during the study period of 10 years. Patients' records were reviewed for demographic data such as age, sex, ethnicity, clinical features, therapy and results of laboratory tests. RESULTS: Fever was the most common presenting symptom and diarrhoea was more common than constipation. Isolation of S typhi from blood and/or stools was the most important diagnostic tool *85.2%) and of these 99% had significant Widal titres. Clinical and bacteriological relapse occurred in 5 children (3%) who were successfully treated with ceftriaxone. The absence of mortality and low level of complications indicates either a mild nature of the disease or to early recognition or prompt and appropriate therapy.

Ceftriaxone↗

PubMed1996

An immunohistochemical method for the diagnosis of melioidosis.

In order to assess the usefulness of immunohistochemistry in the diagnosis of melioidosis, an infection by Burkholderia pseudomallei, polyclonal antibodies were applied to tissues from known cases of melioidosis and to other infected tissues. Formalin-fixed, paraffin-embedded tissues were stained by a modified immunoperoxidase technique. In autopsy tissues with inflammatory lesions of melioidosis, the cytoplasm of phagocytes and intact bacilli, both intra- and extracellular, were stained very strongly positive. Relatively more focal positive staining was observed in some but not all surgical biopsies from proven cases of melioidosis. In granulomas staining was mainly found in the central necrotic areas, with little staining of peripheral phagocytes. All control materials stained negative. Immunohistochemistry appears to be a useful diagnostic tool in melioidosis.

Adolescent↗