Large radiopaque lesion in the posterior mandible: A challenging case.

Radiopaque lesions of the jawbones are frequently encountered in dental radiographs. A variety of conditions such as chronic inflammation, soft tissue calcifications, fibrosseous lesions, odontogenic tumors, and bone neoplasms can manifest as radiopaque lesions on the jawbones. These radiopaque lesions are often difficult to distinguish from each other, hence making the formulation of differential diagnosis challenging. A thorough patient's history and clinical examination supplemented by appropriate investigations will enable the clinician in narrowing down the differential diagnosis and to identify the condition accurately. Presented here is a case of the large radiopaque lesion on posterior mandible surrounded by lytic areas in a 20-year-old male patient.

Incidence of constitutive and inducible clindamycin resistance among hospital-associated Staphylococcus aureus.

Clindamycin is one of the important alternative antibiotics in the therapy of Staphylococcus aureus infections. Clinical failure of clindamycin therapy has been reported due to multiple mechanisms that confer resistance to macrolides, lincosamides and Streptogramin B (MLSB) antibiotics. In vitro routine tests for clindamycin susceptibility may fail to detect inducible clindamycin resistance due to erm genes, resulting in the treatment failure. Although data from the developed countries have shown to be enormity of the problem, data from the developing countries are lacking. The aim of the study was to distinguish different resistance phenotypes in erythromycin-resistant S. aureus by a simple double-disc diffusion test (D test). A total of 153 S. aureus isolates were subjected to routine antibiotic susceptibility testing, including cefoxitin disc (30 µg) and by oxacillin screen agar. Inducible clindamycin resistance was tested by 'D test' as per CLSI guidelines. Odds ratios (OR) and 95 % confidence intervals (95 % CI) were calculated. P values were calculated using SPSS (version 18). Among 153 S. aureus isolates, 42 (27.45 %) were resistant to methicillin, whereas 111 (72.54 %) were methicillin susceptible. Out of the 63 (41.17 %) erythromycin-resistant S. aureus isolates, 14 (9.15 %) showed inducible resistance [P = 0.0002, odds ratio (OR) 18.30; 95 % confidence interval (CI) 8.72-25.77), 20 (13.07 %)] showed constitutive resistance (P = 0.002, OR 14.38, 95 % CI 5.33-21.49), while the remaining 29 (18.95 %) showed inducible phenotype. Inducible and constitutive resistance was found to be higher in MSSA when compared with MRSA. Clinical laboratories should perform D test routinely to guide the clinicians about the inducible clindamycin resistance and to prevent misuse of antibiotics.

Prevalence of ESBL, AmpC ß-lactamases and MRSA among uropathogens and its antibiogram.

Urinary tract infections (UTIs) are one of the most common bacterial infections in humans. Current knowledge on antimicrobial susceptibility pattern is essential for appropriate therapy. Therefore the aim of the present study was to determine the distribution and antibiotic susceptibility pattern of bacterial strains, with special reference to ESBL, AmpC ß-lactamase and MRSA production. A total of 325 clinical isolates were collected from UTI patients from various tertiary care hospitals over a period of 6 months (June 2011 to December 2011). The antimicrobial susceptibility to various drugs was studied by the disc diffusion method as guided by CLSI guidelines. Confirmation of the extended spectrum ß-lactamase (ESBL), AmpC ß-lactamase and methicillin resistant Staphylococcus aureus (MRSA) production was done by an E-test respectively. Of the 325 isolates, 225 were characterized as gram negative and 77 isolates as S. aureus isolates. The majority (69.3 %) of the isolates were from females compared to males (30.7 %). Prevalence of ESBL and AmpC ß-lactamase and the coexistence of the phenotype (ESBL+ AmpC ß-lactamase) and MRSA in the urinary isolates were found to be 48.9 %, 20.4 %, 6.2 % and 27.5 % respectively. Ampicillin/sulbactam, norfloxacin should be no longer considered as first line of drugs for UTI, because of high resistance. Parentral drugs such as aminoglycosides, carbapenems and piperacillin/tazobactum can be the alternative choice for complicated UTI. Also, control measures such as judicious use of antibiotics, formulation of infection committee may control the spread of resistance.

Occurrence of Plasmid-Mediated AmpC ß-Lactamases Among Escherichia coli and Klebsiella pneumoniae Clinical Isolates in a Tertiary Care Hospital in Bangalore.

Therapeutic options for infections caused by gram-negative organisms expressing plasmid-mediated AmpC ß-lactamases are limited because these organisms are usually resistant to all the ß-lactam antibiotics, except for cefepime, cefpirome and the carbapenems. These organisms are a major concern in nosocomial infections and should therefore be monitored in surveillance studies. Hence, this study was aimed out to determine the prevalence of plasmid-mediated AmpC ß-lactamases in E. coli and K. pneumoniae from a tertiary care in Bangalore. A total of 63 E. coli and 27 K. pneumoniae were collected from a tertiary care hospital in Bangalore from February 2008 to July 2008. The isolates with decreased susceptibility to cefoxitin were subjected to confirmation test with three dimensional extract tests. Minimum inhibitory concentrations (MICs) were determined by agar dilution method. Conjugation experiments, plasmid profiling and susceptibility testing were carried out to investigate the underlying mechanism of resistance. In our study, 52 (57.7%) isolates showed resistance to cefoxitin, the occurrence of AmpC was found to be 7.7% of the total isolates. Plasmid analysis of the selected isolates showed the presence of a single plasmid of 26 kb in E. coli and 2 Kb in K. pneumoniae. Plasmid-mediated AmpC ß-lactamases were found in 11.1% of K. pneumoniae and in 6.3% of E. coli. Curing and conjugation experiments showed that resistance to cephamycins and cephalosporins was plasmid-mediated. Our study has demonstrated the occurrence of plasmid-mediated AmpC in E. coli and K. pneumoniae which illustrates the importance of molecular surveillance in tracking AmpC-producing strains at general hospitals and emphasizes the need for epidemiological monitoring.