Quorum sensing in prokaryotic biology refers to the ability of a bacterium to sense information from other cells in the population when they reach a critical concentration (i.e. a Quorum) and communicate with them. The "language" used for this intercellular communication is based on small, self-generated signal molecules called as autoinducers. Quorum sensing is thought to afford pathogenic bacteria a mechanism to minimize host immune responses by delaying the production of tissue-damaging virulence factors until sufficient bacteria have amassed and are prepared to overwhelm host defense mechanisms and establish infection. Quorum sensing systems are studied in a large number of gram-negative bacterial species belonging to α, β, and γ subclasses of proteobacteria. Among the pathogenic bacteria, Pseudomonas aeruginosa is perhaps the best understood in terms of the virulence factors regulated and the role the Quorum sensing plays in pathogenicity. Presently, Quorum sensing is considered as a potential novel target for antimicrobial therapy to control multi/all drug-resistant infections. This paper reviews Quorum sensing in gram positive and gram negative bacteria and its role in biofilm formation.

Background: Human Immunodeficiency Virus (HIV) is the most powerful risk factor for the progression of Mycobacterium tuberculosis infection to Tuberculosis (TB) disease. TB accelerates the progression of HIV infection to AIDS and shortens the survival of such patients. Aim: To determine the seroprevalence of HIV infection among TB confirmed patients in a tertiary care center in Mumbai in view of the significance of HIV in TB. Its association with gender and age was also determined. Materials and Methods: Blood samples were collected by venipuncture from 432 TB patients and their HIV status was determined. HIV antibody detection was carried out as per Strategy III, National AIDS Control Organisation (NACO) guidelines. Statistical analysis was carried out by applying the Chi-square test. Results and Conclusion: Of the 432 patients screened, 9% (39) were HIV positive. The prevalence of co-infection was higher among females (9.4%) than the male (8.7%) patients and highest amongst those aged 21to40 years (13.7%). Co-infection was found to be statistically highly associated with age (p < 0.05). This high prevalence calls for routine screening of TB patients for HIV infection.

Background: Pancytopenia is a relatively common hematological entity. It is a striking feature of many serious and life-threatening illnesses, ranging from simple drug-induced bone marrow hypoplasia, megaloblastic anemia to fatal bone marrow aplasias and leukemias. The severity of pancytopenia and the underlying pathology determine the management and prognosis. Thus, identification of the correct cause will help in implementing appropriate therapy. Objectives: To study the clinical presentations in pancytopenia due to various causes; and to evaluate hematological parameters, including bone marrow aspiration. Materials and Methods: It was a prospective study, and 104 pancytopenic patients were evaluated clinically, along with hematological parameters and bone marrow aspiration in Hematology Unit, Department of Pathology, JJMMC, Davanagere, during the period of September 2005 to September 2007. Results: Among 104 cases studied, age of patients ranged from 2 to 80 years with a mean age of 41 years, and male predominance. Most of the patients presented with generalized weakness and fever. The commonest physical finding was pallor, followed by splenomegaly and hepatomegaly. Dimorphic anemia was the predominant blood picture. Bone marrow aspiration was conclusive in all cases. The commonest marrow finding was hypercellularity with megaloblastic erythropoiesis. The commonest cause for pancytopenia was megaloblastic anemia (74.04%), followed by aplastic anemia (18.26%). Conclusion: The present study concludes that detailed primary hematological investigations along with bone marrow aspiration in cytopenic patients are helpful for understanding disease process and to diagnose or to rule out the causes of cytopenia. These are also helpful in planning further investigations and management.

Background: Patients with 1-5 skin lesions are clinically categorized as paucibacillary for treatment purposes. For betterment and adequate treatment of patients, this grouping needs further study. Aim: To study a group of leprosy patients with 1-5 skin lesions, compare clinical details with histopathological findings and bacteriological status of the skin to evaluate the relevance of this grouping. Materials and Methods: Two-year study involving 31 patients of leprosy with 1-5 skin lesions was included in this study. A number of skin lesions were recorded. Skin biopsies were taken in all patients. The biopsies were evaluated for the type of pathology and acid fast bacilli (AFB) status. Results: Of 31 patients, 19 (61.2%) had single skin lesion, 7 (22.5%) had two lesions, 4 (12.9%) had three lesions, and only one (3.22%) had four lesions, there were no patients with five lesions. Of the 31 patients, 30 (96.7%) were clinically diagnosed as borderline tuberculoid and one patient (3.22%) has tuberculoid leprosy. Skin smears were negative for AFB in all patients. The histological diagnoses were: TT 1 (3.22%), BT 24 (77.41%), and IL 6 (19.2%). AFB were found in 2 (6.45%) out of 31 skin biopsies. Clinicopathological correlation was 76.6% in the BT group. Conclusion: Tissue biopsy findings in 1-5 skin lesions which were not considered relevant for treatment purposes until now should be given a status in the categorization and assessment of severity of the disease. The significance of finding of AFB and histopathology of multibacillary (MB) type of leprosy in tissue biopsies, in patients grouped as PB should be resolved so that patients could be given the drug therapy and duration of therapy they warrant.

Introduction: The resistance to antimicrobial agents among Staphylococci is an increasing problem. This has led to renewed interest in the usage of Macrolide-Lincosamide-Streptogramin B (MLS _B ) antibiotics to treat Staphylococcus aureus (S. aureus) infections. The resistance to macrolide can be mediated by msr A gene coding for efflux mechanism or via erm gene encoding for enzymes that confer inducible or constitutive resistance to MLS _B antibiotics. In vitro routine tests for clindamycin susceptibility may fail to detect inducible clindamycin resistance due to erm genes resulting in treatment failure, thus necessitating the need to detect such resistance by a simple D test on a routine basis. Materials and Methods : One hundred and ninety S. aureus isolates were subjected to routine antibiotic susceptibility testing including oxacillin (1 ΅g) and cefoxitin (30 ΅g) by modified Kirby Bauer disc diffusion method. Inducible resistance to clindamycin in S. aureus was tested by 'D test' as per CLSI guidelines. Results: Twenty (10%) isolates showed inducible clindamycin resistance, 18 (9%) showed constitutive resistance while remaining 16 (8%) showed MS phenotype. Inducible resistance and constitutive resistance were found to be higher in MRSA as compared to MSSA (20%, 16% and 6%, 6%, respectively). Conclusion : Clindamycin is kept as a reserve drug and is usually advocated in severe MRSA infections depending upon the antimicrobial susceptibility results. This study showed that D test should be used as a mandatory method in routine disc diffusion testing to detect inducible clindamycin resistance in Staphylococci for the optimum treatment of patients.

Background: Cerebrovascular disease (CVD) and coronary heart disease (CHD) cause 40%-50% of deaths in developed countries with CVD causing 10%-12% of deaths. Though increased Lipoprotein (a) is a risk factor in developing CHD, its role is poorly defined in etiopathogenesis of CVD. Aims: To find the association of lipoprotein (a) and lipid profile in thrombotic stroke patients after acute phase. Settings and Design: The study was conducted at Kasturba Medical College, Manipal. Twenty one cases of thrombotic stroke and 18 cases of age and sex matched controls were taken for the study. Informed consent was taken from both case and control. Materials and Methods: Overnight fasting sample was collected from both case and control. Serum was separated and parameters such as total cholesterol, triglycerides, high density lipoproteins-C, low density lipoprotein-C, lipoprotein (a), fasting blood sugars were estimated. Statistical analysis: Data were analyzed by SPSS software, Student's t-test, standard deviation (SD), and standard error of mean (SEM), P-value <0.05 is considered to be significant. Results: In this study, we found no statistical significant differences in serum lipid and lipoprotein (a) profile between controls and thrombotic stroke patients. Conclusions: Highest frequency (38%) of stroke was found in the age group of 7080 years. There were other associated risk factors such as diabetes in five cases (24%), hypertension in nine cases (43%), and family history of stroke in four cases. However, further studies are required to evaluate the importance of serum Lp(a) estimation in the assessment as a risk factor for thrombotic stroke.

Background: Resistance to broad-spectrum β lactams, mediated by extended-spectrum β lactamases (ESBLs), is an increasing problem world wide. This resistance poses problems for in vitro testing and reporting. Increased prevalence of ESBLs among Enterobacteriaceae creates a great need for laboratory testing methods that will accurately identify their presence. Materials and Methods: During the study, the Enterobacteriaceae isolated were tested for the presence of ESBL by the National Committee for Clinical Laboratory Standards (NCCLS) screening test, Jarlier double disc synergy (approximation) test (DDST) and NCCLS phenotypic confirmatory test (PCT), and compared their efficiency in detection. Results: A total of 313 Enterobacteriaceae were isolated and tested for the presence of ESBL. NCCLS PCT identified 200 (63.89%) as ESBL producers and DDST identified 176 (56.23%), with a P-value of <0.001. Among the screening agents, ceftazidime had a better sensitivity (89.49%) and specificity (95.74%). Conclusions: Close monitoring of the susceptibility pattern of isolates and careful spacing with specific discs can identify many ESBL producers. Ceftazidime has a better sensitivity and specificity as a screening agent. A combination of different tests can be useful for accurate identification.

Background: The purpose of this work was to study the acquisition of new antibiotic-resistant genes carried by extended spectrum β-lactamase (ESBL)-producing Enterobacteriaceae via horizontal transfer to understand their rampant spread in the hospitals and in the community. Materials and Methods: A retrospective analysis of 120 ESBL screen-positive isolates of Escherichia coli and Klebsiella pneumoniae, which were subjected to antimicrobial susceptibility testing, was carried out. The Double Disc Synergy Test (DDST) and Inhibitor-Potentiation Disc Diffusion Test (IPDD) were employed for confirmation of ESBL activity. The transferability of the associated antibiotic resistance for amoxicillin, amikacin, gentamicin, cefotaxime and ceftriaxone was elucidated by intra- and intergenus conjugation in Escherichia coli under laboratory as well as under simulated environmental conditions. Transformation experiments using plasmids isolated by alkaline lysis method were performed to study the transferability of resistance genes in Klebsiella pneumoniae isolates. Results : ESBL production was indicated in 20% each of the Escherichia coli and Klebsiella pneumoniae isolates. All the ESBL isolates showed co- resistance to various other groups of antibiotics, including 3GC antibiotics, though all the isolates were sensitive to both the carbapenems tested. Conjugation-mediated transfer of resistance under laboratory as well as environmental conditions at a frequency of 3-4 x 10 ^-5 , and transformation-mediated dissemination of cefotaxime and gentamicin resistance shed light on the propensity of ESBL producers for horizontal transfer. Conclusions: The transfer of resistant markers indicated availability of a large pool of resistance genes in the hospital setting as well as in the environment, facilitating long-term persistence of organisms.

Mycetoma is a chronic infection, frequently seen in tropical and sub-tropical countries and is considered as an occupational disease. Nocardia species though it can infect immunocompetent individuals, it most commonly affects immunocompromised patients. A 50-year-old male, farmer presented to our hospital with serosanguineous discharging swelling over the dorsum of right foot. We have isolated Nocardia asteroides from the tissue sample. Speciation of this isolate was carried out based on phenotypic methods. Hereby we report a case of Actinomycetes Mycetoma in an immunocompetent individual.

Paecilomyces is a colonizing fungal species which usually causes keratitis, endocarditis, sinusitis, nephritis, fungemia, cutaneous, and subcutaneous infections in immunocompromised host. Very rarely, it causes similar infection in immunocompetent host without any risk factors. We report a case of maxillary sinusitis due to Paecilomyces lilacinus in a 65-year-old immunocompetent male, who presented with a subcutaneous swelling below the left eye. The lesion was excised by surgery and treated with itraconazole for 6 months based on culture and sensitivity. After 1 year of follow up, he is free of symptoms with no evidence of recurrence.

Myelodysplastic syndrome (MDS) represents one of the most challenging health-related problems in the elderly, characterized by dysplastic morphology in the bone marrow in association with ineffective hematopoiesis. Hypoplastic MDS (h-MDS) accounts for 12-17% of all patients with MDS and has yet to be shown to alter the disease course or prognosis. The concept that T-cell-mediated autoimmunity contributes to bone marrow failure in MDS has been widely accepted due to hematologic improvement after immunosuppressive therapy. T-cell expansion is known to occur in these patients, but development of chronic T-cell disorders, especially T-prolymphocytic leukemia (PLL) in a hypocellular MDS is extremely rare, which has an aggressive course. The possible explanation for the association between the two disorders is that T-PLL might arise from a clonally arranged MDS stem cell. We report a unique case of h-MDS with non-progressive pancytopenia and severe hypocellular marrow for 2 years, followed by T-PLL within few months.

A 43-year-old perimenopausal lady presented with bleeding per vagina and lower abdominal pain. On evaluation, she had cervical polyp, which expelled spontaneously during the per speculum examination. Histopathology revealed malignant mixed Mullerian tumor. Extended hysterectomy with salphingo oophorectomy was carried out, which showed bilateral fallopian tube carcinoma and leiomyoma uterus. The patient was treated with carboplatin regime and found to be disease-free for 1 year. This case presented because of a rare combination of the lesions.

Epignathus is an extremely rare oropharyngeal teratoma that commonly arises from the palate, leading to a high mortality (80-100%) due to airway obstruction in the neonatal period. We present a case of epignathus immature teratoma with fetiform features, originating from basisphenoid in a 28-week preterm male baby, who succumbed to death immediately after birth. Since epignathus is a life-threatening condition at the time of delivery, a prenatal diagnosis is essential to coordinate the treatment and appropriate management by securing the airway, either by endotracheal intubation or tracheostomy followed by complete resection of the tumor.