Morphological changes in oral mucosa of rabbits induced by light emitting diode [LED] used as dental curing light

A dental curing light is apiece of dental tool that is used for the hardening of light cure composites. Many studies have shown these lights induce changes in DNA, mitosis and mitochondria through free radicals production. Light emitting diode [LED] are most commonly used and claim less hazards to the adjacent soft tissues. Current study was therefore designed to observe the morphological changes induced by light emitting diode [LED] as a dental curing light source in oral mucosa of experimental animals

Fifty rabbits were divided into 5 groups [4 experimental and 5th as a control group]. Cervical margin of central incisors of each animal in the experimental groups was exposed 3 times with LED light; duration of each exposure being 40 seconds with a gap of 30 seconds. Punch biopsies were taken after 24 hours, 48 hours, Iweek and 2weeks from group 1, 2, 3 and 4 animals respectively

Results showed ulceration [4%], acanthosis and vascular pathological changes [100%] enlarge [bulbous] rete ridges [97.5%], basal layer vacuolization [85%], acantholysis [27.5%] and atypical mitosis [10%] in all the experimental animals. With passage of time, a significant increase [P=0.000] in frequency of basal cell hyperplasia [90% in group 1 to 100% in group 4] and basal layer atypia [70% in group 1 to 90% in group 4] was observed. While inflammation dropped from 100% in group 1 to 0% in group 4 [P=0.000] due to healing of tissues. Changes were similar to the previous studies except some severe effects like atypical mitosis and basal layer atypia were observed which may be attributed to increase in number of light exposures in our study that is in compliance with the clinical practice in our set up

These findings may help in creating awareness among the dental practitioners to use dental curing lights with caution keeping appropriate safety measures for the adjacent oral soft tissue in consideration

In vitro efficacy of meropenem, colistin and tigecycline against the extended spectrum beta-lactamase producing gram negative bacilli

To compare the in vitro efficacy of meropenem, colistin and tigecycline against extended spectrum Beta-lactamase producing Gram negative bacilli by minimal inhibitory concentration. Cross-sectional descriptive study. Department of Microbiology, Army Medical College, National University of Sciences and Technology, Rawalpindi, from June to December 2010. Routine clinical specimens were subjected to standard microbiological procedures and the isolates were identified to species level. Extended spectrum beta-lactamase producing Gram negative bacilli were detected by Jarlier disc synergy method and confirmed by ceftazidime and ceftazidime-clavulanate Etest. Minimum Inhibitory Concentration [MIC[90]] of meropenem, colistin and tigecycline was determined by Etest [AB BIOMERIUX] and the results were interpreted according to the manufacturer's instructions and Clinical and Laboratory Standards Institute guidelines and Food and Drug Authority recommendations. Results were analyzed by using Statistical Package for the Social Sciences version 20. A total of 52 non-duplicate extended spectrum Beta-lactamase-producing Gram negative bacilli were included in the study. The MIC[90] of tigecycline [0.75 microg/ml] was lowest as compared to the meropenem [2 microg/ml] and colistin [3 microg/ml]. Tigecycline is superior in efficacy against the extended spectrum Beta-lactamase producing Gram negative bacilli as compared to colistin and meropenem

Carbapenem resistant acinetobacter-A major pathogen in a Tertiary Care Hospital

Objective: To determine the frequency of carbapenem resistant Acinetobacter in the Military Hospital Rawalpindi, Pakistan

Study Design: Descriptive study

Place and Duration of Study: Department of Microbiology, Army Medical College, from Oct, 2012 to Feb, 2013

Material and Methods: Clinical specimens like naso-bronchial lavage, blood, pus, sputum and catheter tips were inoculated on blood agar and Mac Conkey agar while the urine samples were inoculated on Cystine Lactose Electrolyte Deficient [CLED] agar. Acinetobacter spp. isolated, were later subjected to antimicrobial susceptibility testing using the modified Kirby-Bauer disc diffusion method on Mueller Hinton agar as per Clinical Laboratory and Standards Institute [CLSI] guidelines

Results: Out of a total of 85 Acinetobacter spp. 62 isolates were found to be carbapenem resistant. They were also found to be 100% resistant to ciprofloxacin and ceftriaxone thus becoming multidrug resistant followed by tazobactam piperacillin [98%] and trimethoprim sulphamethoxazole [92%]. Minimum resistance was seen against tigecycline being 21%

Conclusion: It is concluded from our study that there is a high frequency [72.94%] of resistance to carbapenems in Acinetobacter spp. in our setup which is associated with increased morbidity and mortality due to limited treatment options

Expression of cd 10 in dentigerous cysts and ameloblastomas - a reliable prognosticator

CD 10, a surface glycoprotein, depicts the proliferation potential, differentiation and prognosis of neoplastic cells. Dentigerous Cyst [DC] is the most common developmental odontogenic cyst having high proliferative index thus related with epithelial dysplasia and neoplasms. Ameloblastoma is an uncommon, benign and locally aggressive odontogenic neoplasm with high rate of recurrence after surgery. This study was therefore designed to determine the expression of CD 10 in DCs and ameloblastomas. Twenty-five patients presenting with DCs [n=12] and ameloblastomas [n=13] were selected. Relevant clinical and radiographical findings were recorded and biopsies were submitted for histological diagnosis. CD 10 immunopositivity was assessed by immunohistochemistry in four microscopic high power fields showing maximum number of immunopositive cells. Mean age was 26.5 +/- 11.24 years and 42.07 +/- 9.24 years while male to female ratio was 7:5 and 7:6 for DCs and ameloblastomas respectively. Most of the patients [58.3%] of DCs presented as-ymptomatically while 41.6% patients reported with painful swelling. Comparing, all patients with ameloblastomas presented with painless swelling. Radiographically, all DCs and 46.2% of ameloblastomas were unicystic while 53.8% were multicystic radiolucent lesions. Histologically, epithelial atypia was seen in 50% and 23% of DCs and ameloblastomas respectively. High CD 10 cytoplasmic and membranous immunoreactivity was observed in the superficial epithelial lining of the DCs and the neoplastic epithelial cells of ameloblastomas while the stellate reticulum like cells showed only cytoplasmic immunopositivity. CD 10 expression may indicate neoplastic disposition of DCs while locally invasive and recurrence potential in ameloblastomas

Coagulase negative staphylococci - a fast emerging threat

To determine the frequency of isolation of coagulase-negative staphylococci and their resistance to methicillin over a period of time. The descriptive cross-sectional study was carried out at Army Medical College, Rawalpindi, from June 2009 to May 2012, and comprised clinical samples mostly from patients admitted to the intensive care unit. They were inoculated onto appropriate culture media depending upon the specimen. After 24-hour incubation at 35°C, coagulase-negative staphylococci were identified on the basis of colony morphology, gram staining, a positive catalase and a negative tube coagulase test. Methicillin resistance among the isolated staphylococci was determined using a 30microg Cefoxitin disc as per the Clinical and Laboratory Standards Institute protocol. Number of coagulase-negative staphylococci for each year and their methicillin resistance rates were calculated. A comparison was made with methicillin resistant staphylococcus aureus] isolated during the same period. Of the total 1331 specimens studies over three years, 581[43.65%] were coagulase-negative staphylococci. The rate of coagulase-negative staphylococci and methicillin resistance was higher each year; 110[26.6%] in May 2009-Jun 2010, 134[36.5%] in 2011, and 337[61%] in 2012. Methicillin resistance rates also increased from 25[22.7%] to 46[34.3%] and then to 201[59.6%] in 2012.Maximum isolated specimens came from blood 311[53.5%], followed by pus/swabs 204[35.1%]. The frequency of isolation of coagulase-negative staphylococci and its methicillin resistance among hospitalised patients is on the rise

Frequency and antibiogram of vancomycin resistant enterococcus in a tertiary care hospital

To determine the frequency of Vancomycin Resistant Enterococcus [VRE] in a tertiary care hospital of Rawalpindi, Pakistan. Observational, cross-sectional study. Department of Microbiology, Army Medical College, Rawalpindi, from May 2011 to May 2012. Vancomycin resistant Enterococcus isolated from the clinical specimens including blood, pus, double lumen tip, ascitic fluid, tracheal aspirate, non-directed bronchial lavage [NBL], cerebrospinal fluid [CSF], high vaginal swab [HVS] and catheter tips were cultured on blood agar and MacConkey agar, while the urine samples were grown on cystine lactose electrolyte deficient agar. Later the antimicrobial susceptibility testing of the isolates was carried out using the modified Kirby-Bauer disc diffusion method on Mueller Hinton agar. A total of 190 enterococci were isolated. Of these, 22 [11.57%] were found to be resistant to vancomycin. The antimicrobial sensitivity pattern revealed maximum resistance against ampicillin [86.36%] followed by erythromycin [81.81%] and gentamicin [68.18%] while all the isolates were 100% susceptible to chloramphenicol and linezolid. The frequency of VRE was 11.57% with the highest susceptibility to linezolid and chloramphenicol

In vitro efficacy of Colistin against multi-drug resistant Pseudomonas aeruginosa by minimum inhibitory concentration

Multi-drug resistant bacteria are an important cause of mortality and morbidity. In the management of various infections, timely detection and appropriate treatment, in accordance with the culture and sensitivity reports can help improve the treatment outcome. Colistin is a bactericidal antibiotic which is emerging as a reliable solution for treating infections with multi-drug resistant Gram negative bacilli. The aim of this study was to find out the in-vitro efficacy of colistin against multidrug resistant Pseudomonas aeruginosa isolates by minimum inhibitory concentration. This cross sectional, descriptive study was conducted in the Department of Microbiology, Army Medical College, National University of Sciences and Technology, Islamabad from February 2010 to January 2011. Antimicrobial sensitivity testing was done on Pseudomonas aeruginosa isolated from routine clinical specimens received and the strains which appeared resistant to at least one antimicrobial agent in three or more anti-pseudomonal antimicrobial categories were subjected to the Colistin Etest. The MIC endpoint of colistin was read, as per manufacturer's instructions [AB Biodisk, Solna, Sweden]. The isolates showing MIC of 2micro.g/ml or less were considered sensitive, those with 4-6 micro.g/ml as intermediate and >/= 8 micro.gg/ml as resistant. MIC[50] and MIC[90] of colistin against MDR Pseudomonas aeruginosa was determined. A total of 52 MDR Pseudomonas aeruginosa strains were isolated during the period of the study. The highest percentage was isolated from urine [36%] followed by respiratory tract infections [18%] and pus specimens [20%]. The highest percentage of these isolates was found to be susceptible to colistin followed by piperacillin-tazobactam and cefoperazone-sulbactam. A total of 36 [69%] isolates were sensitive, 10 [20%] were intermediate and 6 [11%] were resistant to colistin by Kirby Bauer disc diffusion method. MIC[50] was found to be l.0 micro.gg/ml while MIC[90] was 3.0 micro.gg/ml. Colistin is a reliable solution in cases of infections with MDR, XDR or PDR Pseudomonas aeruginosa

Frequency and antibiogram of multi-drug resistant pseudomonas aeruginosa

To find out the frequency and susceptibility pattern of multi-drug resistant [MDR] Pseudomonas aeruginosa in clinical specimens. Cross-sectional observational study. Department of Microbiology, Army Medical College, National University of Sciences and Technology [NUST], Rawalpindi, from January to September 2010. Routine clinical specimens were subjected to standard microbiological procedures and the isolates were identified to the species level. The antibiotics susceptibility was determined by Kirby Bauer Disc diffusion method and the results were interpreted according to the Clinical and Laboratory Standards Institute [CLSI] guidelines. The frequency of MDR Pseudomonas aeruginosa among all the Pseudomonas aeruginosa strains isolated was found to be 22.7%. These isolates were most sensitive to Colistin followed by Piperacillin-Tazobactam and Cefoperazone-Sulbactum. Increasing fequency of infections due to MDR Pseudomonas aeruginosa is an emerging threat in our set up which can be prevented by prescribing antibiotics judiciously and by adopting proper disinfection measures