Understanding the clinico-microbiological spectrum of common ear, nose and throat infections in sikkim, India.

Sir,

The aim of our investigations was to evaluate the current microbiological pattern of ear, nose and throat (ENT) infections and the antibiotic sensitivity pattern at a tertiary care teaching hospital in Sikkim from May 2007 to April 2009. Two hundred and ninety-five samples (64 nasal, 189 throat, and 42 aural) were collected from clinically diagnosed cases of acute tonsillitis, acute pharyngitis, acute rhinitis, acute and chronic sinusitis, otitis externa, acute and chronic suppurative otitis media. The samples were cultured on sheep blood (5%), chocolate, and Mac Conkey agar plates, incubated at 37°C aerobically (Mac Conkey) and in 5% carbon dioxide (blood and chocolate agar) and examined at 24 and 48 h.[1] Aural swabs from cases of otitis externa were cultured on Sabouraud's dextrose agar. Group A β-hemolytic streptococci (GABS) were identified by determining bacitracin sensitivity. Throat swabs were also cultured on chocolate agar for recovery of Haemophilus species. The antibiotic susceptibility test was performed on Muller Hinton agar by the modified Kirby Bauer disc diffusion method following the criteria of Clinical and Laboratory Standards Institute.[2] Overall, less than half (47.46%) were culture positive isolates; positivity was more among adults (72.86%). The pediatric group had higher ear involvement (61.90%), whereas in the adults infection was more in throat (81.48%). Culture positivity was more in ear (92.86%), followed by nose (51.56%) and throat (35.45%). Staphylococcus aureus was the most common isolate from ear (65%), nose (96.97%), and throat (53.73%); associated organisms were chiefly Streptococcus pyogenes, Klebsiella, and Haemophilus influenza. Pseudomonas aeruginosa was isolated in ear and nasal infections. S. aureus from nose were most sensitive to cefuroxime (84.37%) followed by clindamycin (71.87%) and cloxacillin (62.50%); S. aureus from throat were mostly sensitive to cloxacillin (77.77%) followed by clindamycin (61.11%) and cefuroxime (55.55%); from aural swabs a majority of S. aureus were sensitive to clindamycin (69.32%) followed by cefuroxime (61.53%) and penicillin (57.69%). A majority of S. pyogenes isolated from throat were sensitive to penicillin (84.61%) followed by clindamycin (76.92%) and cefuroxime (65.38%). Among the gram-negative isolates P. aeruginosa isolated from ear, nose, and throat were entirely sensitive to cotrimoxazole, gentamicin, cefotaxime, and cefuroxime. Proteus mirabilis and Klebsiella pneumoniae isolates from ear were all sensitive to gentamicin, cefotaxime, ciprofloxacin, and cefuroxime. Of total six cases of otitis externa, Aspergillus niger was isolated from two cases and Candida albicans from one case.

Rohtak study noted that GABS and was cultured from 15% to 36% of children with sore throat and was the causal agent in 10% of adult pharyngitis. Polymicrobial nature of chronic suppurative otitis media (CSOM) was noted in both pediatric (70.8%) and adult (71.4%) cases. In CSOM, S. aureus in children and in adult P. aeruginosa was the most common aerobic isolate; sensitivity to cefuroxime was 72.2%. Among anaerobes higher sensitivity was seen to metronidazole (98.6%), clindamycin (95.7%), and chloramphenicol (98.6%).[3] Aarhus University Hospital study reported that the bacterial flora in ENT infections was dominated by S. pneumoniae, all 100% susceptible to penicillin.[4] In the Nepal study, the most common isolates were S. aureus (69.2%). The overall sensitivity was to amoxicillin (53.84%), cloxacillin (53.84%), ciprofloxacin (46.15%), gentamicin (46.15%), and cephalosporin (46.15%) and resistance to erythromycin, tetracycline, cotrimoxazole and norfloxacin.[5] To sum up, there was a diverse pattern of antibiotic sensitivity to first line drugs to commonly isolated organisms that indicate these as the growing public health concern in this part of India.