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Biomedical subjects

M K Lalitha

Publications and source records attributed to M K Lalitha.

At least 37 records · Page 2Linked to original sources
PubMed2000

Persistent rhinorrhoea in rural Indian children: prevalence and consequences.

To determine whether persistent rhinorrhoea constitutes a significant problem requiring intervention, 17 rural day care centres (Balwadis) in Tamilnadu, India, were visited. Among 414 children in the Balwadis 92 (22 per cent) children with persistent rhinorrhoea (15 days duration or longer) were identified. Demographic and clinical data and nasopharyngeal swabs for bacterial culture were obtained from 56 such children and 91 age-matched controls from the same Balwadi. Type of housing or nutritional status did not appear to be significant risk factors. There was a significantly higher number of children aged 5-15 years in the household of cases as compared to controls (1.23 +/- 1.08 vs. 0.83 +/- 0.95, p = 0.02). Other illnesses were noted in 25 (44.6 per cent) cases and seven (7.7 per cent) controls (OR 11.5; CI, 4.13-33.4; p < 0.00001). Notably, chronic ear discharge was noted in 6 (11.7 per cent) cases but in none of the controls (p = 0.007). Streptococcus pneumoniae was isolated from nasopharyngeal swabs in 42/49 (85.7 per cent) cases and 44/80 (55 per cent) controls (p < 0.001) and H. influenzae from seven cases and five controls; S. pneumoniae was isolated in all children with chronic ear discharge and H. influenzae from one child. Serotypes of pneumococci commonly associated with otitis media, i.e., types 6, 14, 19, and 23 were isolated from 25 (51 per cent) cases and 16 (20 per cent) controls (OR 4.17; 95% CI, 1.78-9.85; p < 0.001). Persistent rhinorrhoea, presumably due to pneumococcus, is a common condition among rural Indian children and appears to be associated with chronic otitis media.

Adolescent↗
PubMed2000

Systemic bacterial infections in bone marrow transplant patients.

The clinical microbiology department at CMC&H, Vellore in conjunction with the haematology department carries out routine surveillance of patients admitted to the hematology department. Since 1994 in a sample population of 55 patients with various underlying clinical conditions who have had bone marrow transplant, sepsis was observed in 16 patients (29%). The predominant Gram negatives associated with sepsis were non-fermenting Gram negative bacilli and all the 5 Gram positives were coagulase negative staphylococci. These organisms were susceptible to most of the routinely used antimicrobial agents. Continued surveillance is needed to determine changing trends with respect to organisms causing systemic infections and their susceptibility to antimicrobials.

Adolescent↗
PubMed1999

Nasopharyngeal colonization of infants in southern India with Streptococcus pneumoniae.

To investigate the dynamics of nasopharyngeal colonization with Streptococcus pneumoniae, and to determine the prevalent serogroups/types (SGT) and their antimicrobial susceptibility, we studied 100 infants attending our well-baby clinic. Nasopharyngeal swab specimens were obtained at 6, 10, 14, 18 and 22 weeks and at 9 and 18 months of age and submitted for culture, serotyping and antimicrobial susceptibility testing of S. pneumoniae. Colonization with pneumococcus was seen on at least one occasion in 81 infants. The median age of acquisition was 11 weeks and the median duration of carriage was 1 3 months. The common SGTs identified were 6, 19, 14 and 15. SGT 1, which was a common invasive isolate in children in our hospital during this period, was not isolated from these children. Sequential colonization by 2, 3 or 4 SGTs was observed in 18, 5 and 2 children, respectively. Resistance to penicillin, chloramphenicol, cotrimoxazole and erythromycin was observed in 0, 13 (6%) 11 (5 %) and 5 (3 %) isolates, respectively. There was a significant difference in susceptibility to cotrimoxazole between colonizing and invasive isolates (5 % vs. 40 %, P<0.0001).

Drug Resistance, Microbial↗
PubMed1999

Spread of drug-resistant Streptococcus pneumoniae in Asian countries: Asian Network for Surveillance of Resistant Pathogens (ANSORP) Study.

Antimicrobial susceptibility of 996 isolates of Streptococcus pneumoniae from clinical specimens was investigated in 11 Asian countries from September 1996 to June 1997. Korea had the greatest frequency of nonsusceptible strains to penicillin with 79.7%, followed by Japan (65.3%), Vietnam (60.8%), Thailand (57.9%), Sri Lanka (41.2%), Taiwan (38.7%), Singapore (23.1%), Indonesia (21.0%), China (9.8%), Malaysia (9.0%), and India (3.8%). Serotypes 23F and 19F were the most common. Pulsed-field gel electrophoresis (PFGE) of 154 isolates from Asian countries showed several major PFGE patterns. The serotype 23F Spanish clone shared the same PFGE pattern with strains from Korea, Japan, Singapore, Taiwan, Thailand, and Malaysia. Fingerprinting analysis of pbp1a, pbp2x, and pbp2b genes of 12 strains from six countries also showed identical fingerprints of penicillin-binding protein genes in most strains. These data suggest the possible introduction and spread of international epidemic clones into Asian countries and the increasing problems of pneumococcal drug resistance in Asian countries for the first time.

Aminoacyltransferases↗
PubMed1999

Serotyping of Streptococcus pneumoniae by coagglutination with 12 pooled antisera.

We report on the performance of a recently introduced commercial chessboard method using 12 antisera, in comparison with that of the 55-antiserum panel used in determining the serogroups and types (SGTs) of Streptococcus pneumoniae, both of which were carried out by a coagglutination technique. Of a total of 150 strains of S. pneumoniae studied, 135 (90%) belonged to the SGTs represented in the 23-valent pneumococcal vaccine; of these, 130 (96.3%) were identified as the same SGTs by both typing methods. The remaining five strains showed cross-reactivity with more than two pools by the chessboard method, but could be assigned to a single SGT by the Quellung test. The 96.3% concordance of the chessboard method suggests it can be adopted for determination of the SGTs of S. pneumoniae in laboratories.

Agglutination Tests↗
PubMed1999

Epidemiological typing of Streptococcus pneumoniae from various sources in Sweden and India using Box A PCR fingerprinting.

Epidemiological typing of Streptococcus pneumoniae is essential to determine strain relatedness and also to trace resistant clones. The novel Box A PCR assay was used for characterization of S. pneumoniae isolates from two Scandinavian countries and to compare those from India on the Asian continent. In addition, the assay was employed to determine the clonality of 25 pneumococcal strains from an outbreak in a day-care centre in Linköping, Sweden. All 25 showed a unique pattern with 100% homology for 24 of them, thereby establishing the clonal nature of the outbreak. The pneumococcal strains involved in the outbreak belonged to serotype 9 and were resistant to penicillin, with an MIC value of 2 mg/l. Thirty-eight genotypes were obtained when the Box A results were analysed by computer (Molecular Analyst Software with GelCompar). The discriminatory index of the method was D=0.98, which indicates excellent performance. No major segregation of strains from the different geographical locations was observed when a lower level of similarity was used for typing (80%, 13 types). However, at the level chosen for genotyping, 95% (38 genotypes) there was a clear geographical segregation. No correlation between genotype and serotype was seen as strains from a common place of origin were most often of different serotypes. Computer-assisted analysis of the results of Box A PCR typing facilitated the evaluation.

DNA Fingerprinting↗
PubMed1999

Changing trend in susceptibility pattern of Streptococcus pneumoniae to penicillin in India.

Prior to 1995 all strains of Streptococcus pneumoniae isolated at a tertiary care hospital in south India were uniformly susceptible to penicillin. However, since late 1995 strains of S. pneumoniae with intermediate resistance to penicillin have been observed. Altogether there were 25 such isolates, 9 from invasive (5 from CSF as well as blood, 1 from pleural fluid and 3 from CSF alone) and 16 from noninvasive sites (6 from throat, 6 from sputum, 3 from eye and 1 from ear) respectively, thus 4.6 per cent of S. pneumoniae showed intermediate resistance of a total of 535 strains studied so far. The minimum inhibitory concentration (MIC) values of penicillin, erythromycin, chloramphenicol and cefotaxime were determined by agar dilution method and for confirmation, E test was carried out for penicillin alone. The MIC range obtained for penicillin was between 0.125-1.0 microgram/ml. Kirby-Bauer disc diffusion method was adopted for testing of erythromycin, chloramphenicol, co-trimoxazole, cefotaxime, tetracycline and vancomycin. We observed that none of the strains with intermediate resistance to penicillin were multidrug resistant. These strains belonged predominantly to serotype 14 (n = 10), 7B (n = 9), 19A (n = 3), 7F (n = 2) and 23F (n = 1). Clonality was not observed in the 5 representative strains subjected to Box A finger printing method.

Anti-Bacterial Agents↗
PubMed1998

PCR-Enzyme immunoassay for detection of Streptococcus pneumoniae DNA in cerebrospinal fluid samples from patients with culture-negative meningitis.

A PCR-based assay was developed to amplify a conserved region of the pneumococcal autolysin gene. The amplified product was labelled with digoxigenin-labelled dUTP and was detected with a biotin-labelled probe in an enzyme immunoassay (EIA). The assay was initially tested with suspensions of various serotypes of Streptococcus pneumoniae and other gram-positive and gram-negative bacteria and was then applied to cerebrospinal fluid (CSF) specimens from patients with meningitis and those with other neurological disorders. The assay detected all the serotypes of S. pneumoniae tested, whereas all the other bacterial strains tested were negative. Seven of the 8 CSF specimens positive for pneumococcus by culture or latex agglutination (LA) were positive by PCR-EIA, whereas all 10 specimens positive for other organisms were negative. Among 11 patients with clinically diagnosed meningitis but with negative culture and LA results, 5 were positive by PCR-EIA. The assay was negative for all but one patient without meningitis; it was positive with the CSF from a child with immunodeficiency and pneumococcal abscesses on the scalp. PCR-EIA is a useful tool for the diagnosis of meningitis, especially when culture and LA are negative because of prior antibiotic treatment.

Child↗
PubMed1997

Reports on surveillance of antimicrobial resistance in individual countries.

In preparation for the meeting of the World Health Organization Working Group on Monitoring and Management of Bacterial Resistance to Antimicrobial Agents, representatives of 10 countries were asked to provide brief reports on the status of surveillance in their countries. Some gave extensive information on the methods used to test susceptibility of nosocomial pathogens to a variety of antibiotics; some described in detail the network of reference laboratories available to hospitals and individual clinicians for monitoring, identifying, and testing infectious agents; others chose to describe how their countries deal with the resistance of the most frequently isolated pathogen to a commonly used drug. The following summary of these reports shows the broad range of problems encountered and solutions undertaken by these 10 countries in dealing with the increasingly alarming problem of bacterial resistance to antimicrobial agents.

Algeria↗
PubMed1997

E test as an alternative to conventional MIC determination for surveillance of drug resistant Streptococcus pneumoniae.

A commercial E test was compared with the standard agar dilution method for the determination of minimum inhibitory concentration (MIC) of penicillin, erythromycin, chloramphenicol and cefotaxime for 36 strains of Streptococcus pneumoniae from patients with invasive diseases. Additional strains were tested for MIC values for penicillin (6), erythromycin (14) and cefotaxime (13) for a better statistical evaluation. Besides, 5 reference standards with predetermined MIC values obtained from WHO pneumococcal reference center at Copenhagen, Denmark were tested for penicillin and erythromycin, for quality assessment using both agar dilution as well as E test methods. An overall agreement within +/- 2 dilutions was noted for 97 per cent of the strains tested for all the antimicrobials. A high degree of correlation was noted for erythromycin (r = 1), penicillin (r = 0.99), chloramphenicol (r = 0.95) and cefotaxime (r = 0.9). In MIC determination of a single antimicrobial for diagnostic purpose, E test was found to be more cost effective than conventional agar dilution method. E test was simple to perform, easy to interpret and a valid method for MIC determination of antimicrobials for S. pneumoniae in our center.

Drug Resistance, Microbial↗
PubMed1996

Modified latex agglutination test for rapid detection of Streptococcus pneumoniae and haemophilus influenzae in cerebrospinal fluid and direct serotyping of Streptococcus pneumoniae.

A modified latex agglutination test was designed and evaluated for the rapid detection of Streptococcus pneumoniae and haemophilus influenzae type b capsular antigens, and for direct serotyping of Streptococcus pneumoniae in the cerebrospinal fluid. Reagents were prepared by sensitizing latex particles with Omniserum (against 83 capsular serotypes of pneumococci) and Haemophilus influenzae type b burro antiserum. For serotyping reagents, latex particles were similarly coated with nine pneumococcal pool (a to I) antisera and 46 individual pneumococcal serogroup/serotype specific antisera. The test was performed on cerebrospinal fluid from 298 patients with suspected meningitis. Serotyping was done directly on untreated cerebrospinal fluid samples showing positive reactions with the Omniserum reagent. Pneumococcal or Haemophilus influenzae type b antigens were detected in 41 patients; in 32 of these the etiology was established by culture and in 2 by smear examination. Five of the remaining seven cases were judged clinically and by cytological examination of cerebrospinal fluid to have partially treated bacterial meningitis. In two cases the test was false positive. The overall sensitivity and specificity of the latex agglutination test for the detection of Streptococcus pneumoniae and Haemophilus influenzae type b antigens was 100% and 96.8% respectively. The commonest pneumococcal serotypes were type 1 (30%), types 6 and 19 (10% each). The latex agglutination test is rapid and simple to perform, yielding serotype data directly by testing of cerebrospinal fluid.

Adult↗
PubMed1996

Serotyping of Streptococcus pneumoniae by agglutination assays: a cost-effective technique for developing countries.

There is a need for additional data on the distribution of pneumococcal serotypes in developing countries. We report the use of a coagglutination (COA) and a latex agglutination (LA) test for serotyping Streptococcus pneumoniae which were evaluated using 114 clinical isolates in Vellore, India. In tests to serotype 30 fresh isolates of pneumococci from meningitis (8 isolates), bacteraemia/septicaemia (21 isolates) and peritonitis (1 isolate) cases, there was complete concordance among the three methods. An additional 20 isolates (11 from cerebrospinal fluid and 9 from blood cultures) were serotyped using both LA and COA, with full agreement between the results. With a further 30 isolates, there was 93% concordance for the COA types with serotypes assigned by a WHO reference laboratory. The COA and LA serotyping results were equivalent in accuracy to those obtained using quellung serotyping. Both these agglutination tests are rapid, valid, and relatively cheap, and with appropriate validation by reference laboratories they could be more widely used in developing countries to obtain local and regional data on pneumococcal serotype distribution.

Agglutination Tests↗
PubMed1996

Prevalence of pneumococcal serotypes in invasive diseases in southern India.

Forty two pneumococcal strains obtained in Vellore, Tamil Nadu, from 42 patients with invasive diseases, namely pneumonia, meningitis, or peritonitis were typed. Over one-third of pneumococci in children and nearly half in adults were serotype followed by serogroups/types 5, 6 and 7 which were most common in children and adults taken together. These 4 serogroups/types accounted for 11 (79%) of 14 strains in children and 20 (71%) of 28 strains in adults. The remaining 11 strains belonged to 8 serogroups/types, namely 3, 4, 10, 11, 12, 13, 19 and 20.

Adolescent↗