Bacterial Viability within Dental Calculus: An Untrodden, Inquisitive Clinico-Patho- Microbiological Research.

INTRODUCTION: Chronic inflammatory periodontal diseases i.e. gingivitis and periodontitis are one of the most common afflictions faced by human beings. Dental plaque, which is a pool of pathogenic microorganisms, remains to be current mainstay in etiopathogenesis. Dental calculus, which is a mineralized product of this plaque remains ignored and is considered merely as an ash heap of minor significance. However, the intriguing array in disease etiopathogenesis bulldozed researchers to suspect the role of calculus in disease chrysalis but still the viability of bacteria inside calculus and thus its pathogenicity remains an intricacy; the answer to which lies in the Pandora's Box. AIM: The present study was undertaken to investigate the viability of bacteria within dental calculus along with their identification. Also, to classify dental calculus on the basis of mineralization and to observe the variation of viable microflora found in dental calculus with the extent of mineralization and disease severity. MATERIALS AND METHODS: A total of 60 samples were obtained, by harvesting two samples of supragingival calculus from each patient having chronic inflammatory periodontal disease. These samples were divided into two groups (Group A and Group B). Samples of Group A were kept non-irradiated and samples of Group B were exposed to UV radiation. The samples were categorized into less, moderately and highly mineralized according to the force required for crushing them. All the crushed calculus samples were then divided into three parts. These were used for dark-field microscopy, gram staining and bacterial cultures. Bacterial identification of the cultures obtained was also carried out by performing various biochemical assays. RESULTS: The present study revealed the presence of motile spirochaetes within the samples under dark-field microscope. Gram staining revealed presence of numerous gram positive cocci and gram negative bacilli. Bacterial cultures showed growth of variety of aerobic and capnophilic microorganisms. CONCLUSION: The present study concludes the presence of viable aerobic and capnophilic bacteria inside dental calculus which may reside within the lacunae and channels in the calculus.

Prevalence of extended spectrum beta lactamase producing Escherichia coli and Klebsiella pneumoniae urinary isolates in a tertiary care hospital in Kathmandu, Nepal.

BACKGROUND: Escherichia coli and Klebsiella pneumoniae are the major bacterial pathogens being isolated and reported from mid stream urine (MSU) specimens, globally. These uropathogens are mostly implicated as the major extended spectrum beta-lactamase (ESBL) producers, severely limiting the therapeutic management in cases of urinary tract infections. Limited studies had been reported from Nepal investigating the ESBL producers among uropathogens. This study was designed to assess the prevalence of ESBL producing E.coli and K. pneumoniae in urinary isolates at a centrally located major tertiary care hospital in Kathmandu valley, Nepal. METHODS: Between September 2011 and May 2012, during the nine months period, 6308 MSU specimens were collected aseptically from the same number of clinically suspected patients of urinary tract infections. The samples were cultured on MacConkey agar and blood agar. The isolates with significant bacteriuria (105 CFU / ml) were identified based on standard laboratory procedures. Antimicrobial susceptibility tests were carried out using various antimicrobial discs alongwith ceftriaxone on E.coli and K. pneumoniae isolates by Kirby Bauer disc diffusion method as per the recommendations of CLSI. On initial screening with ceftriaxone (30 µg) disc showing resistance was then confirmed for ESBL production by phenotypic confirmatory disc diffusion test (PCDDT) using ceftazidime (30 ug) and ceftazidime + clavulanic acid (30 µg + 10ug) disc as per guidelines of CLSI (2011). RESULTS: Out of a total of 6308 MSU specimens investigated for significant bacteriuria, E.coli isolates were 444 (7.04%) and K.pneuminiae were 145 (2.3%) making a total of 589 (9.34%). Initial screening with ceftriaxone disc revealed 155 isolates of E.coli and 70 isolates of K.pneumoniae to be resistant. Further testing by PCDDT method showed 60/444 (=13.51%) of E. coli and 24/145 (=16.55%) of K. pneumoniae isolates to be confirmed ESBL producers. These ESBL - producer uropathogens showed high degree of resistance to ceftriaxone (100.0%), amoxycillin, fluoroquinolones and co-trimoxazole. CONCLUSION: An emerging and moderately high prevalence of ESBL-producing E. coli and K. pneumoniae was observed and confirmed in the urinary isolates investigated. It is essential to have a regular and routine monitoring of ESBL producing clinical isolates in laboratory practice.

Diagnostic value of serum adenosine deaminase levels in sputum smear negative pulmonary tuberculosis patients in Nepalese population

Objective: To assess the levels of adenosine deaminase (ADA) in serum in patients with sputum smear negative pulmonary tuberculosis (SNPTB) and to compare it with serum ADA levels in patients with non-tuberculous pulmonary disease - chronic obstructive pulmonary disease (COPD) and with healthy control group and to explore its validity as a diagnostic marker in serum in SNPTB patients.Methods:Three groups of study populations were made. Group I: SNPTB - 142 cases, Group II:non-tubercular pulmonary disease - COPD - 40 cases, Group III: healthy controls - 80 cases. Serum samples were collected and ADA assay was done by the method of Guisti and Galanti. Results: ADA levels (Mean±SD, U/L) in the three groups were as follows: Group I: 42.26±21.22, Group II: 23.31±8.22, Group III: 18.88±6.67. Difference between Group I and Group III was statistically significant (P < 0.0001). The test showed a high specificity 91.25% (95% confidence interval - CI 83.00 - 95.7) and a sensitivity of 83.10% (95% CI 76.08-88.37) in Group I. Positive predictive value, negative predictive value, positive likelihood ratio, negative likelihood ratio and accuracy in Group I were 94.00%, 69.52%, 9.49, 0.18 and 82.43% respectively.Conclusions: Overall assessment of the use of serum ADA levels as a diagnostic biochemical marker in smear-negative pulmonary tuberculosis patients showed promising results. Studies with a larger population group are required to validate its use as a routine diagnostic test in these cases.

Evidence for HIV-2 infection in Nepal.

Assessment of the presence and prevalence of HIV-2 antibodies in patients attending the Universal College of Medical Sciences Teaching Hospital, Bhairahawa, western Nepal was done. A total of 1534 patients sera were screened for the presence of HIV-1 and HIV-2 antibodies from March 2000 to May 2003. A total of 3 (0.2%) patients were found to be sero-positive for HIV-2 antibodies. Out of the above three patients, 1 (0.1%) was infected with HIV-2 only and the remaining 2 (0.1%) were infected with HIV-1 and HIV-2 both. This evidence of the presence of HIV-2 presence implicates serious outcomes as HIV-2 has not been reported from hospital patients in Nepal.

Status of infectious disease markers among blood donors in a teaching hospital, Bhairahawa, western Nepal.

A cross-sectional group of 1548 blood donors (voluntary--554 and replacement--994 blood donors) during the period February 2001 to April 2003 at Blood Bank Centre (being run by Nepal Red Cross Society) in our Teaching Hospital in Bhairahawa, were studied and screened for antibodies to Human immunodeficiency virus type 1 and type 2 (HIV- 1 & 2), Hepatitis C virus (HCV) and hepatitis B surface antigen (HBsAg) by enzyme immunoassays and for reagin antibody for syphils by (Rapid Plasma Reagin, RPR) flocculation method. The results revealed that the overall prevalence of anti-HIV-1 was 0.13%, anti-HCV--0.13%, HBsAg positivity--0.45% and RPR reactivity for syphilis was 0.39%. HIV and HCV seropositivity was 0.20% and 0.20% respectively among replacement blood donors. None of the voluntary blood donors were found to be seropositive for HIV and HCV antibodies. HBsAg seropositivity was found to be higher among replacement (0.50%) than voluntary blood donors (0.36%). Voluntary blood donors showed a higher RPR seropositivity (0.72%) than replacement blood donors (0.20%). Males constituted 1418 (91.6%) and females were 130 (8.4%) of the total blood donors studied. The highest numbers of blood donors were in the age group of 15-29 years, both for males 902 (58.27%) and females 96 (6.2%). All the seventeen seropositive cases for all the infectious disease markers studied belonged to the sexually active and productive age group of 15-45 years and all seropositives were males except one female case (i.e HBsAg positive). One blood donor was found to be seropositive for both HIV-1 and HCV infections. None was found to be seropositive for HIV-2. Blood group status was also examined for all the blood donors tested. Maximum numbers of blood donors belonged to blood group O--516 (33.33%), followed by B 497 (32.11%), A 407 (26.29%) and AB 128 (8.27%). None of the seropositive blood donor was found to belonged to blood group AB.