An evaluation of dark field microscopy, culture and commercial serological kits in the diagnosis of leptospirosis.

CONTEXT: This study was conducted to analyze the clinical utility of various leptospira diagnostic modalities. AIMS: To evaluate the role of dark field microscopy (DFM), culture, immunochromatography (IgM Leptocheck), IgM enzyme-linked immunosorbent assay (IgM ELISA), macroscopic slide agglutination test (MSAT) and microscopic agglutination test (MAT) in diagnosing leptospirosis in febrile patients. SETTINGS AND DESIGN: Descriptive study conducted in a tertiary care hospital from January 2011 to April 2012. SUBJECTS AND METHODS: Blood, urine and paired sera from 100 patients with clinical suspicion of leptospirosis (study group) were collected and subjected to DFM, culture, IgM Leptocheck, IgM ELISA and MSAT. Fifty randomly selected sera from febrile patients tested positive for infections other than leptospirosis (control sera) were also subjected to the aforementioned serological assays. All the leptospira seropositive samples were subjected to MAT. STATISTICAL ANALYSIS USED: Positive predictive values (PPV) and coefficient of agreement (kappa). RESULTS: None of the clinical samples showed positivity by DFM. Leptospira inadai was isolated from a urine sample. The seropositivity of IgM Leptocheck, IgM ELISA and MSAT was 16%, 46% and 47%, respectively. The PPV of these assays was 14.3%, 8.7% and 6.5%, respectively. Poor agreement was obtained among these assays. Only four study group leptospira seropositive samples were confirmed by MAT with Australis being the predominant serovar. None of the leptospira-positive control sera were confirmed by MAT. CONCLUSIONS: DFM and culture have limited utility in diagnosing leptospirosis with serology being the mainstay. The present study shows discordant results with the commercially available serological kits. Further studies should be done to evaluate the various diagnostic modalities.

Implication of composite electrode on the functioning of photo-bioelectrocatalytic fuel cell operated with heterotrophic-anoxygenic condition.

Electrode materials play a vital role in biofilm formation and electron conduction for efficient functioning of fuel cells. In the present study, graphite polymer composite electrode (GPF) was evaluated as anode for photo-bioelectrocatalytic fuel cell (PhFC; biophotovoltaic system) and compared with much studied graphite electrode (Gc) with photosynthetic bacteria as biocatalyst under anoxygenic condition. The electrogenic activity noticed in GPF (584mV; 2.67mA) was slightly lower than Gc (604mV; 2.92mA; OL2/HRT2). Consequently, COD removal observed by GPF (87.3%) was lower than Gc (91.8%). The increase in bacterial chlorophyll pigment showed a positive influence on electrogenic activity for both the electrodes. The polarization resistance (OL2 and HRT2 condition) was significantly higher for GPF (330Ω) as compared to Gc (110Ω). It is interesting to note that the performance of GPF is slightly lower than Gc based PhFC. The findings have opened avenues for composite materials for PhFC.

Heterotrophic microalgae cultivation to synergize biodiesel production with waste remediation: progress and perspectives.

Microalgae are inexhaustible feedstock for synthesis of biodiesel rich in polyunsaturated fatty acids (PUFA) and valuable bioactive compounds. Their cultivation is critical in sustaining the global economy in terms of human consumption of food and fuel. When compared to autotrophic cultivation, heterotrophic systems are more suitable for producing high cell densities of microalgae for accumulation of large quantities of lipids (triacylglycerols) which can be converted into biodiesel. Consorted efforts are made in this communication to converge recent literature on heterotrophic cultivation systems with simultaneous wastewater treatment and algal oil production. Challenges faced during large scale production and limiting factors which hinder the microalgae growth are enumerated. A strategic deployment of integrated closed loop biorefinery concept with multi-product recovery is proposed to exploit the full potential of algal systems. Sustainable algae cultivation is essential to produce biofuels leading to green future.

A preliminary report on pulmonary tuberculosis in patient travelers to a rural hospital of South India.

BACKGROUND: Occurrence of pulmonary tuberculosis (PTB) among patient travelers in private rural hospitals are often unknown. OBJECTIVES: The aims of the study were to know the occurrence of PTB among patient travelers visiting PES hospital and to create an information and awareness in the establishment of revised national tuberculosis control program (RNTCP) in PES hospital. PATIENT AND METHODS: Adult patients (18-49yr) with TB-like chest symptoms traveling from different regions to Kuppam were included. Children, pregnant women and critically ill were excluded. Between January-December 2004, 372 such patients visited PES hospital. Two consecutive sputum samples were screened for AFB detection by Ziehl-Neelsen. Presence of AFB in both the smears was considered smear positive TB. Negative smears with X-ray abnormality was considered smear-negative TB. Anti-tubercular drugs were prescribed for TB patients. RESULTS: Of 372 patients visited, 29% were diagnosed as TB. Smear-positive and smear-negative TB were 16.6% and 12.3%, respectively. TB among females (31/113) and males (77/259) were 27.4% and 29.7%, respectively. The peak input of patients was in the months of May (53), March (48) and December (35). CONCLUSION: There is an urgent need for establishment of RNTCP in PES hospital.

Proteus mirabilis and rheumatoid arthritis: no association with the disease.

Proteus mirabilis (PM) is implicated in different studies in the pathogenesis of rheumatoid arthritis (RA) because of the structural homogeneity of its haemolysin B precursor with EQRRAA sequences in DRB 1 haplotype. The aim of the study was to compare the levels of antibodies specific to PM in the sera of patients with RA and healthy controls in our population. Serum samples from 78 consecutive RA patients and 75 healthy controls were analysed for the presence of IgG isotype and total immunoglobulins (IgG + IgA + IgM) against PM using enzyme-linked immunosorbent assay (ELISA) with two kinds of antigen preparations, whole bacteria and SDS-lysed bacterial extract. There was no significant increase in the concentrations of anti- Proteus antibodies (APA) in patients with RA compared to healthy controls in our population, when SDS-lysed bacterial extract or whole bacteria were used as antigen. The APA levels did not correlate with serum CRP levels. We conclude that P. mirabilis has no pathological or aggravating role in RA.

Proteus mirabilis and rheumatoid arthritis: no association with the disease.

Proteus mirabilis(PM) is implicated in different studies in the pathogenesis of rheumatoid arthritis (RA) because of the structural homogeneity of its haemolysin B precursor with EQRRAA sequences in DRB 1 haplotype. The aim of the study was to compare the levels of antibodies specific to PM in the sera of patients with RA and healthy controls in our population. Serum samples from 78 consecutive RA patients and 75 healthy controls were analysed for the presence of IgG isotype and total immunoglobulins (IgG+IgA+IgM) against PM using enzyme-linked immunosorbent assay (ELISA) with two kinds of antigen preparation, whole bacteria and SDS-lysed bacterial extract. There was no significant increase in the concentrations of anti- Proteus antibodies (APA) in patients with RA compared to healthy controls in our population, when SDS-lysed bacterial extract or whole bacteria were used as antigen. The APA levels did not correlate with serum CRP levels. Infection with P. mirabilis is found to have no pathological or aggravating role in RA.

Antibiotic resistance among gram-negative bacteria of lower respiratory tract secretions in hospitalized patients.

Data on antibiotic resistance pattern of gram-negative bacterial isolates of lower respiratory tract secretions of hospitalized patients were fed into WHONET computer and analyzed for the year 1999. Out of 860 samples, 269 (31.2%) were culture positive. Gram-negative bacteria (GNB) accounted for 238 (88.4%) positive samples. Non-fermenting gram-negative bacteria (NFGNB) were found in 34% samples, the other common ones being Klebsiella spp (29.8%) and Pseudomonas spp (17.2%). GNB isolates from tracheal aspirates and sputum were 132 (55.4%) and 106 (44.5%) respectively. Adults (32.7%) and elderly patients (24.3%) recorded higher isolation of GNB as compared to pediatric patients (1.6%). The highest mean resistance among predominant GNB in both tracheal aspirate (96.6%) and sputum (86.9%) was noted to ampicillin while the lowest mean resistance in tracheal aspirate (28%) and sputum (14.3%) was to amikacin. NFGNB of tracheal aspirates and sputum showed highest resistance of 50% and 32% to amikacin, respectively. Pseudomonas spp showed the highest variation in the resistance pattern between tracheal aspirates and sputum samples. Overall mean resistance was highest among tracheal aspirate isolates compared to sputum isolates.

Urinary pathogens' resistance to common antibiotics: a retrospective analysis.

The susceptibility of urinary pathogens to common antibiotics was investigated and the results analysed retrospectively using the WHONET computer program. Of 1776 urine samples (44 catheterized) processed, 510 (28.7%) urinary pathogens were isolated. Of these 510 positive cultures, 455 (89.2%) were gram-negative bacilli, 45 (8.8%) Candida species and 10 (1.9%) gram-positive cocci. Of the 44 catheterized samples, 32 (72.7%) yielded significant bacteriuria and these were mainly gram-negative bacteria (24/32). The commonest pathogen isolated was Escherichia coli (47.3%) followed by Klebsiella species (10.3%), non-fermenters other than Pseudomonas species (9%), Candida species (8.8%), Providentia species (7%), Pseudomonas species (5.6%), Citrobacter species (3.7%), Enterobacter species (3.3%) and Proteus species (2.5%). The isolation of gram-negative bacteria among inpatients and outpatients was 71.6% and 28.3%, respectively. The critical care unit, nephrourology, obstetric and gynaecology, medical and surgical wards were found to be high-risk areas constituting 58.7% of the major isolates. The highest and lowest mean resistance among gram-negative bacteria to common antibiotics was 93.5% to ampicillin and to 61% gentamicin. The mean resistance to norfloxacin, amoxy-clavulanic acid, nitrofurantoin, trimethoprim-sulfamethoxazole and cefazolin was 65%, 67%, 75.5%, 76% and 77.5%, respectively. The most resistant pathogen to common antibiotics was found to be Proteus species (resistance 80% and above). Overall susceptibility testing demonstrated decreased usefulness of common antibiotics and demonstrates a need for a re-evaluation of common antibiotics used in the therapy for urinary tract infection.

A preliminary study on metallo-beta-lactamase producing Pseudomonas aeruginosa in hospitalized patients.

Metallo beta-lactamase (MBL) producing Pseudomonas aeruginosa is an emerging threat and a cause of concern for the physicians treating such infections. The present study was undertaken to know the resistance pattern of P. aeruginosa to beta-lactamase inhibitors and carbapenems, and to detect the presence of MBL among resistant isolates to both groups of antibiotics. Between June-November 2001, 50 P. aeruginosa isolates from clinical specimens were tested for susceptibility to beta-lactamase inhibitors and carbapenems by Kirby-Bauer disc diffusion method. Isolates resistant to both groups of antibiotics were screened for the presence of MBLs by disc diffusion method using 2-mercaptoethanol. Of the 50 isolates, 6 (12%) were resistant to both beta-lactamase inhibitors and carbapenems. All 6 isolates were MBL producers were resistant to all the antibiotics tested. Resistance to piperacillin-tazobactam, cefoperazone-sulbactam and ticarcillin-clavulanic acid was 12, 20 and 36 per cent respectively. Resistance of 12 per cent each was noted to imipenem and meropenem respectively. This is to the best of our knowledge the first report of MBL producing P. aeruginosa from India and suggests the need for early detection, notification and control of spread.

Prevalence of beta hemolytic streptococci carrier rate among schoolchildren in Salem.

A preliminary study was conducted to identify the carriers of beta hemolytic streptococci (BHS) among school children. BHS were identified, grouped by latex agglutination test and tested for susceptibility to penicillin, erythromycin and cefazolin from their throat swabs. Prevalence of BHS was found to be 21.6% with group G (43.2%) as the predominant group followed by group A (28.8%). All the isolates were sensitive to the antibiotics tested. Health cards were issued to the carriers of group A beta hemolytic streptococci.