Biomedical subjects

C M Parry

Publications and source records attributed to C M Parry.

At least 19 recordsLinked to original sources

PubMed2003

Characterization of rotaviruses causing diarrhoea in Vietnamese children.

Faecal samples from 123 children admitted to the Centre for Tropical Diseases in Ho Chi Minh city, Vietnam, with acute watery diarrhoea were screened by negative-stain electron microscopy for viral enteropathogens. In addition to the 48 children who were found to be infected with rotavirus only, one had both rotavirus and astrovirus, two had adenovirus 40/41, and one had astrovirus only. The rotaviruses were subjected to molecular analysis by electropherotyping, G- and P-genotyping (by reverse-transcriptase PCR), and amplicon sequencing. By use of newly designed PCR primers, all 49 isolates could be G-genotyped and all but one P-genotyped. Novel variants of G1-G1*--were the most commonly detected G-genotype and such variants of P[8]-P[8*]--were the second commonest P-genotype. The P[8*] and G1* amplicons were, respectively, only 92%-93.4% and 88.1%-89% similar to the corresponding sequences from the prototype P[8] G1 rotavirus, Wa. Several unusual P- and G-genotype combinations were detected. Four (8%) of the children investigated were each found to be co-infected with two different rotaviruses. These data add to our knowledge of the continuing evolution and diversity of human rotaviruses, and should help in the rational design of vaccines.

Adenoviridae↗

PubMed2002

Diagnosis of adult tuberculous meningitis by use of clinical and laboratory features.

BACKGROUND: The diagnosis of tuberculous meningitis is difficult. Discrimination of cases from those of bacterial meningitis by clinical features alone is often impossible, and current laboratory methods remain inadequate or inaccessible in developing countries. We aimed to create a simple diagnostic aid for tuberculous meningitis in adults on the basis of clinical and basic laboratory features. METHODS: We compared the clinical and laboratory features on admission of 251 adults at an infectious disease hospital in Vietnam who satisfied diagnostic criteria for tuberculous (n=143) or bacterial (n=108) meningitis. Features independently predictive of tuberculous meningitis were modelled by multivariate logistic regression to create a diagnostic rule, and by a classification-tree method. The performance of both diagnostic aids was assessed by resubstitution and prospective test data methods. FINDINGS: Five features were predictive of a diagnosis of tuberculous meningitis: age, length of history, white-blood-cell count, total cerebrospinal fluid white-cell count, and cerebrospinal fluid neutrophil proportion. A diagnostic rule developed from these features was 97% sensitive and 91% specific by resubstitution, and 86% sensitive and 79% specific when applied prospectively to a further 42 adults with tuberculous meningitis, and 33 with bacterial meningitis. The corresponding values for the classification tree were 99% and 93% by resubstitution, and 88% and 70% with prospective test data. INTERPRETATION: This study suggests that simple clinical and laboratory data can help in the diagnosis of adults with tuberculous meningitis. Although the usefulness of the diagnostic rule will vary depending on the prevalence of tuberculosis and HIV-1 infection, we suggest it be applied to adults with meningitis and a low cerebrospinal fluid glucose, particularly in settings with limited microbiological resources.

Adolescent↗

PubMed2002

Isoniazid resistance, mycobacterial genotype and outcome in Vietnamese adults with tuberculous meningitis.

SETTING: Centre for Tropical Diseases, a 500-bed hospital for infectious diseases in Ho Chi Minh City, Vietnam. OBJECTIVE: The factors that determine outcome in adults with tuberculous meningitis are poorly understood. The objective of the study was to investigate the relationship between admission clinical features, HIV infection, drug resistance, mycobacterial genotype and outcome in adults with tuberculous meningitis. DESIGN: Clinical and laboratory data were recorded prospectively for 56 Vietnamese adults with tuberculous meningitis confirmed by culture of cerebrospinal fluid. Variables associated with in-hospital mortality, IV infection, drug resistance and microbial genotype were assessed by univariate and multivariate analysis. RESULTS: Admission coma score independently predicted death in hospital (OR 0.73, 95%CI 0.61-0.87, P = 0.001). HIV-infected adults with tuberculous meningitis were more likely to be infected with Mycobacterium tuberculosis resistant to isoniazid (P = 0.011) and streptomycin (P = 0.002). Isoniazid resistance, streptomycin resistance, HIV infection and microbial genotype were not associated with increased in-hospital mortality. CONCLUSION: Treatment of tuberculous meningitis before the onset of coma saves lives. Resistance to isoniazid and/or streptomycin does not appear to affect outcome.

Adolescent↗

PubMed2001

Serology of typhoid fever in an area of endemicity and its relevance to diagnosis.

Currently, the laboratory diagnosis of typhoid fever is dependent upon either the isolation of Salmonella enterica subsp. enterica serotype Typhi from a clinical sample or the detection of raised titers of agglutinating serum antibodies against the lipopolysaccharide (LPS) (O) or flagellum (H) antigens of serotype Typhi (the Widal test). In this study, the serum antibody responses to the LPS and flagellum antigens of serotype Typhi were investigated with individuals from a region of Vietnam in which typhoid is endemic, and their usefulness for the diagnosis of typhoid fever was evaluated. The antibody responses to both antigens were highly variable among individuals infected with serotype Typhi, and elevated antibody titers were also detected in a high proportion of serum samples from healthy subjects from the community. In-house enzyme-linked immunosorbent assays (ELISAs) for the detection of specific classes of anti-LPS and antiflagellum antibodies were compared with other serologically based tests for the diagnosis of typhoid fever (Widal TO and TH, anti-serotype Typhi immunoglobulin M [IgM] dipstick, and IDeaL TUBEX). At a specificity of > or =0.93, the sensitivities of the different tests were 0.75, 0.55, and 0.52 for the anti-LPS IgM, IgG, and IgA ELISAs, respectively; 0.28 for the antiflagellum IgG ELISA; 0.47 and 0.32 for the Widal TO and TH tests, respectively; and 0.77 for the anti-serotype Typhi IgM dipstick assay. The specificity of the IDeaL TUBEX was below 0.90 (sensitivity, 0.87; specificity, 0.76). The serological assays based on the detection of IgM antibodies against either serotype Typhi LPS (ELISA) or whole bacteria (dipstick) had a significantly higher sensitivity than the Widal TO test when used with a single acute-phase serum sample (P < or = 0.007). These tests could be of use for the diagnosis of typhoid fever in patients who have clinical typhoid fever but are culture negative or in regions where bacterial culturing facilities are not available.

Adolescent↗

PubMed2001

Quantitation of bacteria in bone marrow from patients with typhoid fever: relationship between counts and clinical features.

Enteric fever is the only bacterial infection of humans for which bone marrow examination is routinely recommended. A prospective study of the concentrations of bacteria in the bone marrow and their relationship to clinical features was conducted with 120 Vietnamese patients with suspected enteric fever, of whom 89 had confirmed typhoid fever. Ninety-three percent of the Salmonella enterica serovar Typhi samples isolated were resistant to ampicillin, chloramphenicol, and co-trimoxazole. For 81 patients with uncomplicated typhoid and satisfactory bone marrow aspirates, the number of serovar Typhi CFU in bone marrow aspirates was a median value of 9 (interquartile range [IQR], 1 to 85; range, 0.1 to 1,580) compared to 0.3 (IQR, 0.1 to 10; range, 0.1 to 399) CFU/ml in simultaneously sampled blood. The ratio of individual blood counts to bone marrow counts was 10 (IQR, 2.3 to 97.5). The number of bacteria in blood but not bone marrow was correlated inversely with the duration of preceding fever. Thus, with increasing duration of illness the ratio of bone marrow-to-blood bacterial concentrations increased; the median ratio was 4.8 (IQR, 1 to 27.5) during the first week compared with 158 (IQR, 60 to 397) during the third week. After lysing the host cells, the median ratio of viable bone marrow to blood increased, reflecting the higher concentration of intracellular serovar Typhi in the bone marrow. Effective antibiotic pretreatment had a significantly greater effect in reducing blood counts compared to bone marrow counts (P < 0.001). Thus, bacteria in the bone marrow of typhoid patients are less affected by antibiotic treatment than bacteria in the blood. The numbers of bacteria in bone marrow correlated negatively with the white blood cell (R = -0.3, P = 0.006) and platelet counts (R = -0.32, P = 0.01) and positively with fever clearance time after treatment (R = 0.4, P < 0.001). The bacterial load in bone marrow therefore may reflect the clinical course of the infection, and high levels may suppress neutrophil proliferation.

Adolescent↗

PubMed2000

A broad spectrum secreted chemokine binding protein encoded by a herpesvirus.

Chemokines are a family of small proteins that interact with seven-transmembrane domain receptors and modulate the migration of immune cells into sites of inflammation and infection. The murine gammaherpesvirus 68 M3 gene encodes a secreted 44-kD protein with no sequence similarity to known chemokine receptors. We show that M3 binds a broad range of chemokines, including CC, CXC, C, and CX(3)C chemokines, but does not bind human B cell-specific nor mouse neutrophil-specific CXC chemokines. This herpesvirus chemokine binding protein (hvCKBP) blocks the interaction of chemokines with high-affinity cellular receptors and inhibits chemokine-induced elevation of intracellular calcium levels. hvCKBP is the first soluble chemokine receptor identified in herpesviruses; it represents a novel protein structure with the ability to bind all subfamilies of chemokines in solution and has potential therapeutic applications.

Animals↗

PubMed2000

The reproducibility of sputum gram film interpretation.

OBJECTIVES: To evaluate the reproducibility with which microbiologists interpret Gram-stained sputa and examine the effect of the smear preparation method. METHODS: Two hundred and ten coded slides prepared directly from a purulent portion of sputum (DS) and 140 slides prepared after homogenization of the same sputum (HS) were examined by three experienced microbiologists. A proportion of the slides prepared by each method were recorded and represented to the raters. Intraobserver and interobserver variation was assessed using the kappa statistic (kappa). RESULTS: Evaluation of the smear as being infected and predicting Streptococcus pneumoniae as the infecting organism showed the greatest intraobserver agreement (kappa=0.74-0.82) and interobserver agreement (kappa=0.50-0.82). The agreement concerning the number of cells and infection with Haemophilus influenzae was only fair to moderate. Differences in the interpretation of smears prepared by the two methods could be explained by the intrinsic disagreement that occurs when the same smear is examined twice. The positive predictive value of a positive S. pneumoniae smear for a positive culture ([10(6)/ml) was 81% with the DS and 97% with the HS. CONCLUSION: In this laboratory, a sputum Gram film interpretation suggesting infection with S. pneumoniae was reproducible and predictive of a significant positive culture.

Adolescent↗

PubMed2000

Detection of pneumococcal capsular antigen in saliva of children with pneumonia.

The concentration of pneumococcal capsular antigen (PCA) in saliva was examined in 44 Thai children aged between 2 months and 2 years admitted with community-acquired pneumonia and in 52 healthy controls. None of the children with pneumonia had a positive blood culture. PCA was detected by latex agglutination in the saliva of 12/44 (27%) children with pneumonia compared with 9/52 (17%) of the controls. More cases than controls had a PCA titre > or = 10 (9/44 (20%) vs 1/52 (2%), p < 0.01). Three of the five cases with a saliva PCA titre > or = 1000 were urine PCA antigen-positive. The salivary PCA titres were higher, but not significantly, in children with heavier pneumococcal carriage. Quantitative measurement of PCA in the saliva may be valuable in helping to make an aetiological diagnosis in children with pneumonia.

Antigens, Bacterial↗

PubMed2000

Nasal carriage in Vietnamese children of Streptococcus pneumoniae resistant to multiple antimicrobial agents.

Resistance to antimicrobial agents in Streptococcus pneumoniae is increasing rapidly in many Asian countries. There is little recent information concerning resistance levels in Vietnam. A prospective study of pneumococcal carriage in 911 urban and rural Vietnamese children, of whom 44% were nasal carriers, was performed. Carriage was more common in children <5 years old than in those >/=5 years old (192 of 389 [49.4%] versus 212 of 522 [40.6%]; P, 0.01). A total of 136 of 399 isolates (34%) had intermediate susceptibility to penicillin (MIC, 0.1 to 1 mg/liter), and 76 of 399 isolates (19%) showed resistance (MIC, >1.0 mg/liter). A total of 54 of 399 isolates (13%) had intermediate susceptibility to ceftriaxone, and 3 of 399 isolates (1%) were resistant. Penicillin resistance was 21.7 (95% confidence interval, 7.0 to 67.6) times more common in urban than in rural children (35 versus 2%; P, <0.001). More than 40% of isolates from urban children were also resistant to erythromycin, trimethoprim-sulfamethoxazole, chloramphenicol, and tetracycline. Penicillin resistance was independently associated with an urban location when the age of the child was controlled for. Multidrug resistance (resistance to three or more antimicrobial agent groups) was present in 32% of isolates overall but in 39% of isolates with intermediate susceptibility to penicillin and 86% of isolates with penicillin resistance. The predominant serotypes of the S. pneumoniae isolates were 19, 23, 14, 6, and 18. Almost half of the penicillin-resistant isolates serotyped were serotype 23, and these isolates were often multidrug resistant. This study suggests that resistance to penicillin and other antimicrobial agents is common in carriage isolates of S. pneumoniae from children in Vietnam.

Adolescent↗

PubMed2000

A randomized controlled comparison of azithromycin and ofloxacin for treatment of multidrug-resistant or nalidixic acid-resistant enteric fever.

To examine the efficacy and safety of short courses of azithromycin and ofloxacin for treating multidrug-resistant (MDR, i.e., resistant to chloramphenicol, ampicillin, and cotrimoxazole) and nalidixic acid-resistant enteric fever, azithromycin (1 g once daily for 5 days at 20 mg/kg/day) and ofloxacin (200 mg orally twice a day for 5 days at 8 mg/kg/day) were compared in an open randomized study in adults admitted to a hospital with uncomplicated enteric fever. A total of 88 blood culture-confirmed patients were enrolled in the study (86 with Salmonella enterica serovar Typhi and 2 with S. enterica serovar Paratyphi A). Of these, 44 received azithromycin and 44 ofloxacin. A total of 68 of 87 (78%) isolates were MDR serovar Typhi, and 46 of 87 (53%) were nalidixic acid resistant. The MIC(90) (range) of azithromycin was 8 (4 to 16) microgram/ml for the isolates. The MIC(90) (range) of ofloxacin for the nalidixic acid-sensitive isolates was 0.03 (0.015 to 0.06) microgram/ml and for the nalidixic acid-resistant isolates it was 0.5 (0.25 to 1.0) microgram/ml. There was no significant difference in the overall clinical cure rate with ofloxacin and azithromycin (38 of 44 [86.4%] versus 42 of 44 [95.5%]; P = 0.27) or in the patients infected with nalidixic acid-resistant typhoid (17 of 21 [81.0%] versus 24 of 25 [96.0%]; P = 0.16). However, patients with nalidixic acid-resistant typhoid treated with ofloxacin had a longer fever clearance time compared with those treated with azithromycin (174 [60 to 264] versus 135 [72 to 186] h; P = 0.004) and had positive fecal cultures after the end of treatment (7 of 17 [41%] versus 0 of 19 [0%]; P = 0.002). Both antibiotics were well tolerated. A 5-day course of azithromycin was effective for the treatment of enteric fever due to MDR and nalidixic-acid-resistant serovar Typhi, whereas the ofloxacin regimen chosen was less satisfactory for these strains.

Adolescent↗

PubMed2000

Tetanus.

Explore the source record for details and available documents.

Adolescent↗

PubMed1999

Melioidosis in Southern Vietnam: clinical surveillance and environmental sampling.

From 1992-1998, Burkholderia pseudomallei was isolated from only 9 (0.25%) of 3653 cultures of blood from febrile patients admitted to the Centre for Tropical Diseases in Ho Chi Minh City, an infectious disease referral center for southern Vietnam. Soil was sampled from 407 sites in 147 rice fields along the 5 major roads radiating from Ho Chi Minh City. B. pseudomallei was isolated from 73 sites (18%) in 39 rice fields (27%), but only 15 (21%) of the 71 isolates from 9 (6%) of 147 fields were the virulent l-arabinose (ara)-negative biotype. All except 1 of the fields with the ara-negative biotype were close to the homes of the patients with melioidosis. The low incidence of melioidosis in the provinces around Ho Chi Minh City may be explained by the restricted distribution of ara-negative B. pseudomallei in the soil in this area.

Burkholderia pseudomallei↗

PubMed1999

A comparative study of ofloxacin and cefixime for treatment of typhoid fever in children. The Dong Nai Pediatric Center Typhoid Study Group.

BACKGROUND: Despite concerns about safety in children, fluoroquinolone antibiotics have become the treatment of choice in patients with multidrug-resistant typhoid fever in Vietnam. However, quinolone-resistant strains of Salmonella typhi have recently been reported from Vietnam; and if quinolone resistance becomes established, alternative oral treatment options will be needed. OBJECTIVE: Cefixime, an orally administered third generation cephalosporin, was compared with ofloxacin for the treatment of uncomplicated typhoid fever in children. METHODS: In an open trial children with suspected typhoid fever were randomized to receive either ofloxacin (10 mg/kg/day in two divided doses) for 5 days or cefixime (20 mg/kg/day in two divided doses) for 7 days. RESULTS: S. typhi was isolated from 82 patients (44 in the cefixime group, 38 in the ofloxacin group) and 70 (85%) of the isolates were multidrug-resistant. Median (95% confidence interval, range) fever clearance times were 4.4 (4 to 5.2, 0.2 to 9.9) days for ofloxacin recipients and 8.5 (4.2 to 9, 1.8 to 15.2) days for cefixime-treated patients (P < 0.0001). There were 11 treatment failures (10 acute and one relapse) in the cefixime group and 1 acute treatment failure in the ofloxacin group (mean difference, 22%; 95% confidence interval, 9 to 36%). CONCLUSION: Short course treatment with cefixime may provide a useful alternative treatment in cases of uncomplicated typhoid fever in children, but it is less effective than short course treatment with ofloxacin.

Adolescent↗

PubMed1999

Molecular typing of multiple-antibiotic-resistant Salmonella enterica serovar Typhi from Vietnam: application to acute and relapse cases of typhoid fever.

The rate of multiple-antibiotic resistance is increasing among Salmonella enterica serovar Typhi strains in Southeast Asia. Pulsed-field gel electrophoresis (PFGE) and other typing methods were used to analyze drug-resistant and -susceptible organisms isolated from patients with typhoid fever in several districts in southern Vietnam. Multiple PFGE and phage typing patterns were detected, although individual patients were infected with strains of a single type. The PFGE patterns were stable when the S. enterica serovar Typhi strains were passaged many times in vitro on laboratory medium. Paired S. enterica serovar Typhi isolates recovered from the blood and bone marrow of individual patients exhibited similar PFGE patterns. Typing of S. enterica serovar Typhi isolates from patients with relapses of typhoid indicated that the majority of relapses were caused by the same S. enterica serovar Typhi strain that was isolated during the initial infection. However, some individuals were infected with distinct and presumably newly acquired S. enterica serovar Typhi isolates.

Bacterial Typing Techniques↗

PubMed1999

Value of a single-tube widal test in diagnosis of typhoid fever in Vietnam.

The diagnostic value of an acute-phase single-tube Widal test for suspected typhoid fever was evaluated with 2,000 Vietnamese patients admitted to an infectious disease referral hospital between 1993 and 1998. Test patients had suspected typhoid fever and a blood culture positive for Salmonella typhi (n= 1,400) or Salmonella paratyphi A (n = 45). Control patients had a febrile illness for which another cause was confirmed (malaria [n = 103], dengue [n = 76], or bacteremia due to another microorganism [n = 156] or tetanus (n = 265). An O-agglutinin titer of >/=100 was found in 18% of the febrile controls and 7% of the tetanus patients. Corresponding values for H agglutinins were 8 and 1%, respectively. The O-agglutinin titer was >/=100 in 83% of the blood culture-positive typhoid fever cases, and the H-agglutinin titer was >/=100 in 67%. The disease prevalence in investigated patients in this hospital was 30.8% (95% confidence interval, 26.8 to 35.1%); at this prevalence, an elevated level of H agglutinins gave better positive predictive values for typhoid fever than did O agglutinins. With a cutoff titer of >/=200 for O agglutinin or >/=100 for H agglutinin, the Widal test would diagnose correctly 74% of the blood culture-positive cases of typhoid fever. However, 14% of the positive results would be false-positive, and 10% of the negative results would be false-negative. The Widal test can be helpful in the laboratory diagnosis of typhoid fever in Vietnam if interpreted with care.

Adolescent↗

PubMed1998

Penicillin vs. erythromycin in the treatment of diphtheria.

In an open-label, randomized trial, 44 Vietnamese children with diphtheria were given penicillin therapy (intramuscular benzylpenicillin, 50,000 U/[kg.d] for 5 days and then oral penicillin, 50 mg/[kg.d] for 5 days), and 42 were given erythromycin therapy (50 mg/[kg.d] orally for 10 days). There were no differences in times to membrane clearance or bacteriologic clearance, but median times to fever clearance were 27 hours (95% confidence interval [CI], 19-30; range, 0-124 hours) for penicillin recipients and 46 hours (95% CI, 34-54; range, 0-148 hours) for erythromycin recipients (P = .0004). In the penicillin group, acute treatment failed for one patient, and one patient relapsed. Three patients in the penicillin group developed diphtheritic myocarditis as evidenced by abnormal electrocardiograms. Erythromycin did not cause prolongation of the QT interval corrected for heart rate. Cultures of specimens from 15 patients (17.4%) were positive for toxigenic Corynebacterium diphtheriae. All isolates were susceptible to penicillin, but for isolates (27%), all of which were from patients who received penicillin treatment, were resistant to erythromycin (minimum inhibitory concentrations, > 64 mg/L). Penicillin is recommended as first-line treatment for diphtheria in Vietnam.

Adolescent↗

PubMed1998

Quantitation of bacteria in blood of typhoid fever patients and relationship between counts and clinical features, transmissibility, and antibiotic resistance.

Salmonella typhi was isolated from 369 and Salmonella paratyphi A was isolated from 6 of 515 Vietnamese patients with suspected enteric fever. Compared with conventional broth culture of blood, direct plating of the buffy coat had a diagnostic sensitivity of 99.5% (95% confidence interval [CI], 97.1 to 100%). Blood bacterial counts were estimated by the pour plate method. The median S. typhi count in blood was 1 CFU/ml (range, <0.3 to 387 CFU/ml), of which a mean of 63% (95% CI, 58 to 67%) were intracellular. The mean number of bacteria per infected leukocyte was 1.3 (interquartile range [IQR], 0.7 to 2.4) CFU/cell (n = 81). Children (< 15 years old; n = 115) had higher median blood bacterial counts than adults (n = 262): 1.5 (range, <0.3 to 387) versus 0.6 (range, <0.3 to 17.7) CFU/ml (P = 0.008), and patients who excreted S. typhi in feces had higher bacteremias than those who did not: a median of 3 (range, <0.3 to 32) versus 1 (range, <0.3 to 68) CFU/ml (P = 0.02). Blood bacterial counts declined with increasing duration of illness (P = 0.002) and were higher in infections caused by multidrug-resistant S. typhi (1.3 [range, <0.3 to 387] CFU/ml; n = 313) than in infections caused by antibiotic-sensitive S. typhi (0.5 [range, <0.3 to 32] CFU/ml; n = 62) (P = 0.006). In a multivariate analysis this proved to be an independent association, suggesting a relationship between antibiotic resistance and virulence in S. typhi.

Adolescent↗

PubMed1998

Untreatable infections?--The challenge of the 21st century.

The triumph of antibiotics over bacterial pathogens that has occurred in the latter half of this century looks increasingly threatened as we approach the new millennium. Increasing resistance in important pathogens such as Mycobacterium tuberculosis, Shigella, and Streptococcus pneumoniae threatens the lives of millions. The increasing problems with drug resistance in (C. diphtheriae, Salmonella typhi and the pneumococcus in Vietnam are presented as examples of the challenge confronting tropical countries.

Bacterial Infections↗