BACKGROUND Staphylococcus aureus is a frequent cause of bacterial infections in both developed and developing countries. The Clinical and Laboratory Standards Institute (CLSI) recommends D-test, which is a phenotypic screening method for inducible Clindamycin resistance. Therefore, all erythromycin resistant S. aureus should be tested for inducible Clindamycin resistance to prevent Clindamycin treatment failures and to report prevalence resistant phenotypes which varies widely. MATERIALS AND METHODS This cross-sectional study was conducted for a period of one year from January 2017 to January 2018. We analysed 125 nonduplicate consecutive isolates of S. aureus isolated from various clinical specimens like pus, wound swab, aspirates, blood and sterile fluids. A total of 125 S. aureus isolates derived from wound infection were evaluated for antimicrobial susceptibility testing by Kirby-Bauer disk diffusion method. Methicillin Resistance was detected using Cefoxitin (30 µg) disk and inducible Clindamycin resistance was determined in all erythromycin resistant isolates by using D-zone test. RESULTS Out of 125 S. aureus isolates of the MRSA 46 (36.6%) were derived from respective Pus samples 19 (41.53%), the S. aureus isolates derived from Wound samples were MRSA 8 (18.03%), the S. aureus isolates derived from Blood samples were MRSA 10 (22.40%), the S. aureus isolates derived from Miscellaneous samples were MRSA 6 (13.66%) and the S. aureus isolates derived from urine samples were MRSA 2 (3.75%). A total of 26 S. aureus isolates showed inducible Clindamycin resistance by giving a positive D-zone test; hence, its prevalence was found to be 21.00% (26/125) with percentage distribution of cMLSB phenotype and MS phenotypes in all S. aureus isolates as 19.4% and 24.6% respectively. The susceptible phenotype (E-S and CD-S) predominated in MSSA (39.75%) as compared to MRSA (13.11%). Whereas, the constitutive resistant (cMLSB) predominated in MRSA (50.27%) as compared to MSSA (15.46%). Both the MS phenotype and the inducible resistant (iMLSB) phenotypes predominated in MSSA (19.87 and 24.92%, respectively) as compared to MRSA (22.40% and 14.20%, respectively). The antimicrobial susceptibility test result of all the 105 S. aureus isolates with iMLSB phenotype revealed that they were 100% sensitive to Vancomycin and Linezolid with moderate sensitivity (71.14%) to Gentamicin, Cefuroxime and least sensitivity (23.81%) to Doxycycline and 20.95% to Ciprofloxacin. CONCLUSION Due to high prevalence of Erythromycin resistance amongst S. aureus isolates, we suggest that D-zone test should be routinely done in all laboratories for appropriate prescription of Clindamycin and thereby preventing emergence of inducible resistant strains and treatment failure.

Introduction: Clindamycin has been used to treat pneumonia and soft tissue and musculoskeletal infections due to MRSA. One important problem in Clindamycin treatment is the risk of clinical failure during therapy caused by MLSB inducible resistance. The Clinical and Laboratory Standards Institute (CLSI) suggest D-test, which is a phenotypic showing technique for inducible Clindamycin resistance. Material and Methods:We analyzed antimicrobial susceptibility testing by Kirby Bauer disk diffusion method. Methicillin resistance was detected with cefoxitin (30 µg) disk and inducible clindamycin resistance was unwavering in all erythromycin resistant isolate by using D-zone test.Results: 100 S. aureus isolate 37 (36.6%) were methicillin resistant (MRSA) and 63 (63.4%) were methicillin-sensitive S. aureus (MSSA). Although, mainstream of the MRSA isolates were imitative from pus samples 15, however, the S. aureus isolates imitative from post-operative wound infection were mainly MRSA 7. A total of 21 S. aureus isolates with iMLSB phenotype shown that they were 100% susceptible to vancomycin and linezolid, with modest sensitivity (71.14%) to gentamicin, cefuroxime and slightest sensitivity to (23.81%) doxycycline, (20.95%) ciprofloxacin. Conclusion:Outstanding to high happening of erythromycin resistance amongst S. aureus isolates, we recommend that D-zone test have to be regularly done in all laboratories for suitable recommendation of clindamycin and thus preventing appearance of inducible resistant strains and management failure.

Introduction: Surgical site infections are most common hospitals acquired infections and are an important cause of morbidity and mortality. The objective of our study is to conclude the causative bacteria and antimicrobial sensitivity of surgical site infections. Material and methods: A total of 275 various clinical samples received in Microbiology Laboratory, Government Medical College, Bettiah (West Champaran) Bihar and Associated Hospital. from March 2018 to April 2019. A total 101 Staphylococcus aureus isolated, were identified by standard biochemical methods. Antibiotic susceptibility testing was performed by Kirby Bauer Disc Diffusion method. Methicillin resistance was detected by using cefoxitin (30µg) disc diffusion method as per CLSI guidelines 2016. Result: Out of the 275 aerobic bacteria which were isolated, 144 were gram positive cocci (52.37%) and 131 were gram negative bacilli (47.63%). The most common pathogen followed by Staphylococcus aureus 101 (36.36%). Other organisms were Escherichia, Pseudomonas, Klebsiella, Citrobacter, Proteus, and Enterococcus. The Antimicrobial profile of 101 Staphylococcus aureus isolates among MRSA, resistance those they were 100% sensitive to linezolid and vancomycin, with moderate sensitivity (71.14%) to cefuroxime, gentamicin and least sensitivity to (23.81%) doxycycline, (20.95%) ciprofloxacin. Conclusion: Isolation of MRSA patients and carriers in the hospitals, regular surveillance, and monitoring of antibiotic susceptibility pattern of the hospital and community of that region regularly and formulation of antibiotic policy may help in reducing the treatment failures.

BACKGROUND Typhoid fever continues to remain a major public health problem, especially in Bihar, due to poor sanitation and personal hygiene. Typhoid fever continues to remain a health problem as the causative organism Salmonella Typhi has developed resistance to many of the antibiotics used. This study was done to evaluate status in antimicrobial susceptibility patterns of Salmonella enterica serovar Typhi (S. Typhi) and S. Paratyphi obtained from blood culture in a tertiary care hospital in Bettiah, Bihar, India. METHODS Blood samples were obtained from patients, suspected with enteric fever. Blood isolates of Salmonella species over a one year period between July 2018 and August 2019 were studied. 120 strains of S. Typhi were isolated. Sensitivity to ampicillin, chloramphenicol, gentamicin, ciprofloxacin and ceftriaxone were tested for antimicrobial susceptibility by Kirby-Bauer disc diffusion method. RESULTS Of the total 120 isolates studied, 68 (56.67%) were S. Typhi and 52 (43.33%) were S. Paratyphi A. Of these isolates, 104 (86.33%) were sensitive to ciprofloxacin (MIC<0.25 mg/ml), 110 (91.67%) were nalidixic acid resistant. Of the 110 nalidixic acid resistant isolates, 104 (86.33%) were susceptible to ciprofloxacin (MIC <0.25 mg/ml). All 120 isolates were sensitive to co-trimoxazole and ceftriaxone, 104 isolated (86.66%) were sensitive to amoxicillin and 110 (91.67%) were sensitive to chloramphenicol. CONCLUSIONS Nalidixic acid resistance screening is not a consistent surrogate indicator of ciprofloxacin resistance. Ciprofloxacin MIC should to be routinely done. The isolates showed a high degree of susceptibility to ampicillin, co-trimoxazole and chloramphenicol. Thus, antibiotics like amoxicillin, co-trimoxazole, and third generation Cephalosporins (Cefotaxime) may once again be useful for the management of enteric fever in tertiary care hospitals in Bettiah, Bihar, India.