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Biomedical subjects

M K Lalitha

Publications and source records attributed to M K Lalitha.

At least 19 recordsLinked to original sources

Reproductive tract infections among young married women in Tamil Nadu, India.

CONTEXT: Women often suffer silently with reproductive tract infections (RTIs). Studies of the prevalence of these infections in South Asia have been hindered by low participation rates, and little is known about rates among the youngest married women. METHODS: A community-based cross-sectional study of RTIs was conducted in 1996-1997 among married women 16-22 years of age in Tamil Nadu, India. The women were questioned about symptoms, received pelvic and speculum examinations and provided samples for laboratory tests. Qualitative and quantitative data on treatment-seeking behavior were collected. RESULTS: Fifty-three percent of women reported gynecologic symptoms, 38% had laboratory findings of RTIs and 14% had clinically diagnosed pelvic inflammatory disease or cervicitis. According to laboratory diagnoses, 15% had sexually transmitted infections and 28% had endogenous infections. Multivariate analysis found that women who worked as agricultural laborers had an elevated likelihood of having a sexually transmitted infection (odds ratio, 2.4), as did those married five or more years (2.1). Two-thirds of symptomatic women had not sought any treatment; the reasons cited were absence of a female provider in the nearby health care center, lack of privacy, distance from home, cost and a perception that their symptoms were normal. CONCLUSIONS: Young married women in this rural Indian community have a high prevalence of RTIs but seldom seek treatment. Education and outreach are needed to reduce the stigma, embarrassment and lack of knowledge related to RTIs. The low social status of women, especially young women, appears to be a significant influence on their low rates of treatment for these conditions.

Adolescent↗

Clinical outcomes of pneumococcal pneumonia caused by antibiotic-resistant strains in asian countries: a study by the Asian Network for Surveillance of Resistant Pathogens.

To evaluate the clinical outcomes of pneumococcal pneumonia caused by antibiotic-resistant strains in Asian countries, we performed a prospective observational study of 233 cases of adult pneumococcal pneumonia in 9 Asian countries from January 2000 to June 2001. Among 233 isolates, 128 (55%) were not susceptible to penicillin (25.3% were intermediately susceptible, and 29.6% were resistant). Clinical severity of pneumococcal pneumonia was not significantly different between antibiotic-resistant and antibiotic-susceptible groups. Mortality rates among patients with pneumococcal pneumonia caused by penicillin-, cephalosporin-, or macrolide-resistant strains were not higher than those with antibiotic-susceptible pneumococcal pneumonia. Bacteremia and mechanical ventilation were significant risk factors for death, but any kind of antibiotic resistance was not associated with increased mortality due to pneumococcal pneumonia. Outcome of pneumococcal pneumonia was not significantly affected by drug resistance, and current antimicrobial regimens are mostly effective in the treatment of pneumococcal pneumonia, despite the widespread emergence of in vitro resistance.

Adolescent↗

Macrolide resistance and genotypic characterization of Streptococcus pneumoniae in Asian countries: a study of the Asian Network for Surveillance of Resistant Pathogens (ANSORP).

OBJECTIVES: To characterize mechanisms of macrolide resistance among Streptococcus pneumoniae from 10 Asian countries during 1998-2001. METHODS: Phenotypic and genotypic characterization of the isolates and their resistance mechanisms. RESULTS: Of 555 isolates studied, 216 (38.9%) were susceptible, 10 (1.8%) were intermediate and 329 (59.3%) were resistant to erythromycin. Vietnam had the highest prevalence of erythromycin resistance (88.3%), followed by Taiwan (87.2%), Korea (85.1%), Hong Kong (76.5%) and China (75.6%). Ribosomal methylation encoded by erm(B) was the most common mechanism of erythromycin resistance in China, Taiwan, Sri Lanka and Korea. In Hong Kong, Singapore, Thailand and Malaysia, efflux encoded by mef(A) was the more common in erythromycin-resistant isolates. In most Asian countries except Hong Kong, Malaysia and Singapore, erm(B) was found in >50% of pneumococcal isolates either alone or in combination with mef(A). The level of erythromycin resistance among pneumococcal isolates in most Asian countries except Thailand and India was very high with MIC(90)s of >128 mg/L. Molecular epidemiological studies suggest the horizontal transfer of the erm(B) gene and clonal dissemination of resistant strains in the Asian region. CONCLUSION: Data confirm that macrolide resistance in pneumococci is a serious problem in many Asian countries.

Alleles↗

Fluoroquinolone resistance in clinical isolates of Streptococcus pneumoniae from Asian countries: ANSORP study.

Seventeen clinical isolates of Streptococcus pneumoniae showing reduced susceptibility to ciprofloxacin (MIC >/= 4 micro g/ml) collected from eight different Asian countries were analyzed by antimicrobial susceptibility, serotyping, pulsed-field gel electrophoresis (PFGE), and DNA sequencing of the quinolone resistance-determining regions (QRDRs) in gyrA, gyrB, parC, and parE. All isolates but one showed more than one amino acid alteration in QRDRs of four responsible genes. Ile460 --> Val in parE was the most common mutation. Data suggest that Lys137 --> Asn in parC may be a primary step in the development of high-level and multiple FQ resistance. An additional mutation of Ser81 --> Phe in gyrA resulted in high-level resistance to ciprofloxacin, levofloxacin, and gatifloxacin, whereas Ser79 --> Phe in parC may exert an important role in the development of moxifloxacin resistance. Two novel amino acid changes in gyrB, Ala390 --> Val and Asn423 --> Thr, were found. Data from PFGE suggest an introduction and local spread of multiple resistant Spain(23F)-1 clone in Hong Kong, but isolates from other Asian countries were not related to this clone.

Anti-Bacterial Agents↗

High prevalence of antimicrobial resistance among clinical Streptococcus pneumoniae isolates in Asia (an ANSORP study).

A total of 685 clinical Streptococcus pneumoniae isolates from patients with pneumococcal diseases were collected from 14 centers in 11 Asian countries from January 2000 to June 2001. The in vitro susceptibilities of the isolates to 14 antimicrobial agents were determined by the broth microdilution test. Among the isolates tested, 483 (52.4%) were not susceptible to penicillin, 23% were intermediate, and 29.4% were penicillin resistant (MICs >/= 2 mg/liter). Isolates from Vietnam showed the highest prevalence of penicillin resistance (71.4%), followed by those from Korea (54.8%), Hong Kong (43.2%), and Taiwan (38.6%). The penicillin MICs at which 90% of isolates are inhibited (MIC(90)s) were 4 mg/liter among isolates from Vietnam, Hong Kong, Korea, and Taiwan. The prevalence of erythromycin resistance was also very high in Vietnam (92.1%), Taiwan (86%), Korea (80.6%), Hong Kong (76.8%), and China (73.9%). The MIC(90)s of erythromycin were >32 mg/liter among isolates from Korea, Vietnam, China, Taiwan, Singapore, Malaysia, and Hong Kong. Isolates from Hong Kong showed the highest rate of ciprofloxacin resistance (11.8%), followed by isolates from Sri Lanka (9.5%), the Philippines (9.1%), and Korea (6.5%). Multilocus sequence typing showed that the spread of the Taiwan(19F) clone and the Spain(23F) clone could be one of the major reasons for the rapid increases in antimicrobial resistance among S. pneumoniae isolates in Asia. Data from the multinational surveillance study clearly documented distinctive increases in the prevalence rates and the levels of antimicrobial resistance among S. pneumoniae isolates in many Asian countries, which are among the highest in the world published to date.

Anti-Infective Agents↗

Comparison of different culture media and storage temperatures for the long-term preservation of Streptococcus pneumoniae in the tropics.

OBJECTIVE: The preservation of Streptococcus pneumoniae by standard freezing methods for subsequent tests--such as serotyping and antibiotic susceptibility--is not possible or is difficult in many developing countries because of the high cost of equipment, inadequate equipment maintenance, and irregular power supply. We evaluated alternative low-cost methods, by comparing different culture media and storage temperatures. METHODS: Clinical isolates of five capsular types (1, 5, 7, 19, and 23) of S. pneumoniae were preserved in rabbit blood, sheep blood, skimmed milk, or glycerol-chocolate broth, and stored at -20 degrees C or -70 degrees C. The cultures were also preserved by lyophilization or sand desiccation, followed by storage at room temperature and 4 degrees C. The viability of the preserved cultures was determined by making serial colony counts on day 0 and after 1 week, 4 weeks, 4 months and 16 months. The viability of cultures preserved by sand desiccation and storage at 4 degrees C was also determined every 6 months for up to 68 months. FINDINGS: Irrespective of the media used, cultures maintained at -20 degrees C became nonviable by the fourth month, while those maintained at -70 degrees C were still viable at 16 months. Cultures preserved by lyophilization or sand desiccation lost their viability by the fourth month when maintained at local room temperature (30-42 degrees C), but remained viable when stored at 4 degrees C for up to 68 months. CONCLUSIONS: Our results confirm that freezing at -70 degrees C, or lyophilization and storage at 4 degrees C are the ideal methods for the preservation of S. pneumoniae. In laboratories where lyophilization is not feasible, sand desiccation and storage at 4 degrees C offers an alternative low-cost method for the long-term preservation of S. pneumoniae.

Cell Culture Techniques↗

Identification of Bacillus anthracis by a simple protective antigen-specific mAb dot-ELISA.

A simple protective antigen (PA)-reactive mAb dot-ELISA was standardized for confirmation of toxin-producing strains of Bacillus anthracis. Twenty-seven clinical isolates were collected from patients clinically suspected of having anthrax. PA was elaborated from these isolates using Casamino acids medium and the culture medium was boiled to kill the cells. PA in boiled culture supernatants was detected using a dot-ELISA. Of the 27 clinical isolates tested, PA was detected in 24 isolates. This was further confirmed by amplifying the PA gene by PCR. This testing procedure is simple to perform, specific and safer than existing procedures, which are added advantages over existing methods of identification of B. anthracis. This test system could be a valuable tool in confirming clinical and environmental isolates of B. anthracis.

Amino Acids↗

Comparison of disc diffusion & E test methods with agar dilution for antimicrobial susceptibility testing of Haemophilus influenzae.

BACKGROUND & OBJECTIVES: Reliable methods of detection of antimicrobial resistance are of paramount importance in the treatment and management of infections caused by Haemophilus influenzae. The objective of the present study was to compare and evaluate the performance of disc diffusion and E test (Epsilometer test) with agar dilution method for antimicrobial susceptibility testing of H. influenzae. METHODS: A total of 46 isolates of H. influenzae from various invasive sites were included as test strains. Antimicrobial susceptibility testing was performed by Kirby-Bauer disc diffusion method for ampicillin, chloramphenicol, trimethoprim-sulphamethoxazole (TMP-SMZ) and cefotaxime. Minimum Inhibitory Concentration (MIC) determination was performed by E test and agar dilution for the same set of antimicrobials. All tests were performed on Haemophilus test medium (HTM). RESULTS: Disc diffusion showed a very major (2%) and minor (4%) interpretative error with TMP-SMZ and minor interpretative errors to ampicillin (13%) and chloramphenicol (24%) when compared to agar dilution method. E test produced only minor interpretative errors to chloramphenicol (7%) and TMP-SMZ (2%) and no interpretative errors with ampicillin and cefotaxime as against agar dilution. E test showed good agreement with agar dilution for each of the antimicrobial tested. INTERPRETATION & CONCLUSION: Disc diffusion test may be used as a preliminary screen for susceptibility testing of H. influenzae. E test is simple, easy to perform and a reliable method for determination of resistance in H. influenzae. However its cost and limited availability in India may limit its use. The reference agar dilution method can be used reliably in routine susceptibility testing of H. influenzae.

Agar↗

Nasopharyngeal carriage of Haemophilus influenzae.

OBJECTIVE: Nasopharyngeal colonization of Haemophilus influenzae (H. influenzae) in young children may be important in developing countries. METHOD: In this study, we screened school going children for carriage of H. influenzae. A total of 44 H. influenzae isolates out of a collection of 162 were characterized for biotypes, capsular serotypes and antibiotic resistance. RESULTS: A significant proportion of H. influenzae (25/44) isolates were serotype b. High antibiotic resistance was observed against commonly administered antibiotics like ampicillin (79%), chloramphenicol (20%), trimethoprim sulfamethoxazole (84%) and erythromycin (95%). Comparison of antibiotic resistance profile of nasopharyngeal isolates was observed to be correlated with those of H. influenzae from disease. CONCLUSION: Multidrug resistant nasopharyngeal H. influenzae in young healthy children may act as reservoir. Monitoring of antibiotic resistance among nasopharyngeal H. influenzae as a surrogate for invasive H. influenzae seems an attractive option.

Age Distribution↗

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

BACKGROUND & OBJECTIVES: Epidemiological typing of Streptococcus pneumoniae is necessary to study genetic relatedness among strains. The Box A PCR assay, a good epidemiological tool for high resolution typing of pneumococcal isolates, was used for comparison of strains of S. pneumoniae from Korea, an area of high penicillin resistance and India with low resistance to penicillin. METHODS: The pneumococcal strains from Indian and Korean sources included in the study belonged to serotypes 19F, 23F, 6A & 6B. The penicillin susceptibility of the strains was confirmed by determination of minimum inhibitory concentration values. The strains were then fingerprinted using the Box A PCR protocol and the results were further analysed by Molecular Analyst Software. RESULTS: The Box fingerprinting technique produced sharp, clear and reproducible banding patterns for strains of S. pneumoniae included in the study. There was no similarity between Indian and Korean strains at the genetic level. Among the Korean strains with similar serotypes, the level of similarity varied. Except for one pair (serotype 23F), that showed a level of homology of about 90 per cent, almost all the others showed less than 80 per cent homology. It was also seen that there was a high percentage of homology (> 90% in nasopharyngeal isolates from India belonging to serotype 19F) between isolates from similar source. Comparison of the Indian and Korean isolates of similar serotype showed low homology, except for one cluster of two strains with serotype 6B which showed 84 per cent homology (blood isolates from India and Korea). INTERPRETATION & CONCLUSION: Box A PCR is a highly discriminatory and useful method for typing S. pneumoniae. The results of the study have shown low levels of homology between strains from within India and also between two geographically distinct areas.

Bacterial Typing Techniques↗

Carriage of antibiotic-resistant pneumococci among Asian children: a multinational surveillance by the Asian Network for Surveillance of Resistant Pathogens (ANSORP).

To investigate the nasal carriage of antibiotic-resistant pneumococci by children, anterior nasal swabs were done for 4963 children <5 years old in 11 countries in Asia and the Middle East. In total, 1105 pneumococci isolates (carriage rate, 22.3%) were collected, 35.8% of which were found to be nonsusceptible to penicillin. Prevalence of penicillin nonsusceptibility was highest in Taiwan (91.3%), followed by Korea (85.8%), Sri Lanka (76.5%), and Vietnam (70.4%). Penicillin resistance was related to residence in urban areas, enrollment in day care, and a history of otitis media. The most common serogroups were 6 (21.5%), 23 (16.5%), and 19 (15.7%). The most common clone, as assessed by pulsed-field gel electrophoresis, was identical to the Spanish 23F clone and to strains of invasive isolates from adult patients. Data in this study documented the high rate of penicillin or multidrug resistance among isolates of pneumococci carried nasally in children in Asia and the Middle East and showed that this is due to the spread of a few predominant clones in the region.

Anti-Bacterial Agents↗

Rapid assay for detection of chloramphenicol acetyl transferase in Haemophilus influenzae.

BACKGROUND & OBJECTIVES: Haemophilus influenzae causes a variety of life threatening infections in humans. Early detection of antimicrobial resistance is of importance in the treatment and management of infection. The modified Slack's method, a simple assay, has been evaluated in this study for the early detection of chloramphenicol resistance. METHODS: Fifty isolates of H. influenzae from invasive and non-invasive sites were included. Antimicrobial susceptibility testing was done by disc diffusion method and minimum inhibitory concentration (MIC) determination was performed for chloramphenicol only. Modified Slack's method was used to test for the production of chloramphenicol acetyl transferase (CAT). RESULTS: Invasive isolates showed higher degree of resistance to chloramphenicol (72%) compared to non-invasive ones (28%). One hundred per cent association was found between results of disc diffusion, MIC and CAT production amongst strains resistant to chloramphenicol. INTERPRETATION & CONCLUSION: The findings suggested that chloramphenicol still remains the drug of choice for treatment for non-invasive infection caused by H. influenzae. Modified Slack's method is a simple, rapid, inexpensive and reliable method for the detection of chloramphenicol resistance amongst H. influenzae.

Adult↗

Rapid diagnosis of acute pyogenic meningitis by a combined PCR dot-blot assay.

A multiplex PCR was employed to amplify unique conserved sequences of DNA from the pathogens Haemophilus influenzae, Neisseria meningitidis and Streptococcus pneumoniae from cerebrospinal fluid samples of patients suffering from acute pyogenic meningitis. The accurate identification of the PCR amplified product was achieved by hybridizing dot-blots of the PCR products to probes which were specific, biotinylated internal sequences of the amplified target DNA. Detection of the hybrids was done in a colour reaction using streptavidin-alkaline phosphatase conjugate and BCIP/NBT substrates. The entire protocol took only 7 h for the correct identification of the pathogen present in clinical samples of cerebrospinal fluid. The sensitivity and specificity were >95%.

Biotin↗

Streptococcus pneumoniae from ophthalmic infections: serotype distribution and penicillin susceptibility.

Streptococcus pneumoniae is one of the pathogens causing infection of the conjunctiva and the uveal tract. The present study began with the observation of two ophthalmic S. pneumoniae isolates showing intermediate resistance to penicillin. Among the 25 isolates of S. pneumoniae from 617 ophthalmic specimens, during the period of 14 months, four were found to exhibit an intermediate resistance to penicillin. Minimum Inhibitory Concentration values ranging from 0.125 microg/mL to 0.25 microg/mL was observed. No multidrug resistant strains were isolated. Serogrouping/typing of the S. pneumoniae revealed the following serogroups/types; 6A (n = 3), 6B (n = 2), 22 (n = 3), 14 (n = 3), 23A (n = 2), and 1 each of 23B, 19A, 7B, 32, 9, 42, 21, 39, 10, 3, and 34. One strain showed cross reaction in pool 29, 35, and 47. These findings represent the first such observation of ophthalmic isolates from India.

Anti-Bacterial Agents↗

Genetic diversity and evidence for acquired antimicrobial resistance in Mycobacterium tuberculosis at a large hospital in South India.

OBJECTIVE: To assess genetic diversity and drug resistance of Mycobacterium tuberculosis isolates collected at Christian Medical College Hospital (CMCH), Vellore, India, between July 1995 and May 1996. MATERIALS AND METHODS: Isolates were subjected to IS6110-based restriction fragment length polymorphism (RFLP) analysis and tested for resistance to isoniazid, rifampin, ethambutol, streptomycin, and pyrazinamide, and DNA from selected strains was sequenced in regions associated with drug resistance. RESULTS: One hundred and one M. tuberculosis isolates were collected from 87 patients with pulmonary tuberculosis. Charts of 69 patients were reviewed for history of tuberculosis illness and treatment. DNA from 29 strains was sequenced in katG, rpoB, and gyrA, and sometimes pncA regions. Analysis by RFLP revealed a high degree of genetic diversity, with no identifiable clusters of infection. Of the strains tested, 51% were resistant to at least one antibiotic, and 43% were resistant to more than one drug. There was a high rate of resistance observed in patients whose charts indicated a history of improperly administered tuberculosis treatment, whereas little drug resistance was observed in patients never previously treated for tuberculosis. Sequencing of genes associated with drug resistance revealed several previously unreported mutations in resistant strains. CONCLUSIONS: This analysis suggests that the cases of tuberculosis in the sample are largely reactivation of long-standing infections and that the drug resistance among patients in CMCH is largely acquired or secondary rather than attributable to the spread of drug-resistant strains.

Antitubercular Agents↗