Phenotypic Detection of Inducible Clindamycin Resistance among Clinical Isolates of Staphylococcus aureus in Bharatpur Hospital

Abstract

Background: Clindamycin is regarded as a reserve drug in the treatment of staphylococcal infections. Among few therapeutic alternatives available for treatment of erythromycin-resistant Staphylococcus aureus infections, clindamycin has several advantages but major limitation in its use is the development of resistance resulting in treatment failure. Routine clindamycin susceptibility test may fail to detect such inducible resistance which can be detected by Double disc diffusion test (D-test). The present study was undertaken to determine the incidence of inducible clindamycin resistance among clinical isolates of S. aureus in a tertiary care hospital in central Nepal. Methods: A cross-sectional study was carried out among the patients visiting Bharatpur Hospital from September to November 2019. A total of 1279 clinical samples were examined for the identification of S. aureus by standard microbiological procedures. Antibiotic susceptibility testing of the isolates was done by Kirby-Bauer disc diffusion method and all the erythromycin-resistant isolates were subjected to D-test for the phenotypic detection of inducible clindamycin resistance according to CLSI guidelines (2016). Results: S. aureus was recovered from 4.5% (58/1279) samples of which 35 isolates were Methicillin-Resistant Staphylococcus aureus (MRSA) and 23 were multi-drug resistant (MDR). Tetracycline was found to be the most effective antibiotic whereas erythromycin was the least effective. D-test revealed that 39.7% isolates showed iMLSB phenotype, 3.5% showed cMLSB phenotype and 56.8% showed MS phenotype. The percentage of inducible and constitutive resistance was seen higher amongst MRSA isolates compared to Methicillin-Sensitive Staphylococcus aureus (MSSA) isolates. Incidence of S. aureus was found higher among females and in the age group 20-30 years and in pus samples (p<0.01). Conclusions: Routine testing of inducible clindamycin resistance is suggested among the clinical isolates of erythromycin-resistant Staphylococci to avoid treatment failure.

Staphylococcus aureus with inducible clindamycin resistance and methicillin resistance in a tertiary hospital in Nepal

“…In this study, about a third of S. aureus (36.5%) were iMLSB phenotypes. Similar findings were reported by studies in Nepal [ 14 , 26 ]. However, lower percentages were reported by other studies in Nepal [ 20 – 25 ] and elsewhere [ 15 – 18 ].…”

“…Likewise, 18.5% of S. aureus were cMLSB phenotypes. Similar findings were reported by different studies in Nepal [ 14 , 26 ] and elsewhere [ 15 , 16 ]. However, lower percentages were reported by different studies in Nepal [ 24 , 26 ].…”

“…Similar findings were reported by studies in Nepal [ 21 , 23 ]. Higher percentages were reported by studies in Nepal [ 14 , 22 , 24 , 26 ] while lower percentages were reported by other studies in Nepal [ 20 , 25 ]. The emergence of resistance to multiple antibiotics among S. aureus is impeding their effective management.…”

“…Similarly, various studies had reported prevalence of inducible clindamycin resistance among S. aureus in the world ranging from 7 to 34% [ 1 , 9 – 12 , 14 – 19 ]. Few studies have reported inducible clindamycin resistance among S. aureus in Nepal ranging from 11 to 40% [ 20 – 26 ]. However, it is largely under-reported as there are limited studies on the detection of methicillin and inducible clindamycin resistance in S. aureus .…”

Clinical Specimens are the Pool of Multidrug- resistant Pseudomonas aeruginosa Harbouring oprL and toxA Virulence Genes: Findings from a Tertiary Hospital of Nepal

“…Resistance to the different classes of antibiotics by P. aeruginosa is due to the loss or reduced copy numbers of oprD and overproduction of active efflux pumps, AmpC β-lactamase and extended-spectrum β-lactamases and their resistance mechanism are classified as intrinsic, acquired, and adaptive [6]. In Nepal, the increasing trend of antimicrobial-resistance bacteria in both clincal and nonclinical settings [11,12,[20][21][22][23][24][25][26] is becoming an alarming health issue. ere is no exact observable scheme for marking antibiotic resistance patterns and their use in Nepal.…”