Inducible Clindamycin Resistant Staphylococcus Aureus Isolates From Tertiary Care Hospital, Bettiah, India

Abstract

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.

Exploration of erythromycin ribosomal methylase (erm) genotypes amongst D+ methicillin-resistant Staphylococcus aureus (MRSA) in Sokoto, Nigeria

“…We found the constitutive (cMLSB) resistance phenotype in this study to be 47.9%, which is higher than the 35.7% (30/84 isolates) reported by Goudarzi et al [28] , and the 28.6% (2/7 isolates) reported by Gadekar et al [27] . Our result is not surprising, as many studies have associated a large percentage of cMLSB with MRSA isolates than MSSA isolates [29] . The majority of the MRSA isolates in this study were D-test negative, suggesting that if a large percentage (47.9%) of our tested isolates were tested with clindamycin, then treatment would be effective.…”

Bacteriological Profile of Surgical Site Infections and Their Antibiogram: A Study From Tertiary Care Hospital in Koshi Region (Northern Bihar)

“…This difference could be due to prolonged hospital stay, instrumentation and other invasive procedures. A comparable prevalence rate of 24, 34.6%, and 36.6% were also reported from Northern Bihar, and West Champaran Bihar17,18,19 Although MRSA from clinical specimens showed higher susceptibility to individual antibiotics when compared with others, we obtained high percentage of multidrug resistant MRSA from these specimens. Poddar CK, et al From Bihar had reported 24% of the MRSA isolated from clinical specimens to be multidrug resistant 17.…”

“…In another study 13 18 Rajak KC, Poddar CK, et al From Bihar reported even a higher percentage of multidrug MRSA but from high risk patients admitted in burns and orthopaedic units. 19 In our study we also looked forward for treatment options for Methicillin resistant S. aureus isolates by detecting their antimicrobial susceptibility to various other antibiotics. It was found that all isolates with Methicillin resistant S. aureus isolates were 100% susceptible to linezolid and vancomycin, followed by moderate susceptibility (70, 14%) to gentamicin, cefuroxime and least susceptibility to doxycycline, ciprofloxacin (22.81% and 20.95% respectively).…”

Antimicrobial Susceptibility of Organisms Isolated from Surgical Site Infection in a Tertiary Care Hospital, Bettiah (West Champaran) Bihar, India

“…A comparable prevalence rate of 24, 34.6%, and 36.6% were also reported from Northern Bihar, and West Champaran Bihar. 17,18,19 Although MRSA from clinical specimens showed higher susceptibility to individual antibiotics when compared with others, we obtained high percentage of multidrug resistant MRSA from these specimens from Bihar had reported 24% of the MRSA isolated from clinical specimens to be multidrug resistant. 17 Northern Bihar had reported a higher percentage of multidrug resistant MRSA.…”