S. aureus are one of the most common skin colonizing bacteria, and are a leading source of nosocomial and community-acquired skin infections. Of 1027 samples, 11.8% yielded S. aureus. S. aureus was higher in pus samples (39.2%). S. aureus is normally found in the environment and skin surface, so it is common in wound swabs and pus samples.

In susceptibility testing, all 38 isolates of S. aureus were sensitive to vancomycin. All 38 isolates of S. aureus were resistant to penicillin-G and ampicillin. Out of 38 S. aureus, 67.5% were MDR, and 50% were MRSA. 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. This persuades the physicians to opt for the use of reserve drugs, like MLSB family. Lower cost, lower side effects, and better tissue penetration make clindamycin a better choice among MLSB family. Clindamycin has been used for the treatment of severe staphylococcal infections, like MRSA. During clindamycin therapy, the iMLSB strains can gradually develop constitutively resistant mutants both, in vitro and in vivo. This leads to treatment failures in certain patients. Hence, the detection of such resistant phenotypes is important to minimize treatment failure. S. aureus resistance to macrolides may be constitutive or inducible clindamycin resistance, or may solely be macrolides-resistant [10]. However, among erythromycin-resistant S. aureus isolates there has been a rise in inducible clindamycin resistance [18]. 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 [20,21,22,23,24,25] and elsewhere [15,16,17,18]. 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]. Higher percentages were reported by different studies in Nepal [20, 22] and elsewhere [17, 18]. Also, 18.5% of S. aureus were MS phenotypes. Similar findings were reported by studies in Nepal [20, 23] while higher percentages were reported by other studies in Nepal [23, 26]. These variances in the reporting of MLSB resistance among S. aureus might be related to changes in circulating clones, as well as disparities in infection prevention measures and antibiotic prescribing trends in different hospital settings. Also, the prevalence of MLSB antibiotic-resistant phenotypes varies based on the geography and the characteristics of subjects, like inpatients or outpatients, hospital or community origin, children or adults, public or private institutions, patients or healthcare workers. This emphasizes the need for surveillance programs at nation, region, or hospital level [15,16,17, 20].

The reporting of MRSA has dramatically risen in recent years. However, there is a stark variation in its reporting among the countries. Inadequate infection-prevention practices in hospitals, indiscriminate antibiotic use, intravascular catheterization, hospitalization in intensive care units, and other factors all contribute to MRSA rise [31]. In this study, 39.4% of S. aureus isolates were MRSA. Similar findings were reported by studies in Nepal [21] and elsewhere [17, 18]. However, higher percentages were reported by other studies in Nepal [22, 23, 26] and elsewhere [11, 14]. And, lower percentages were reported by other studies in Nepal [12, 20, 25] and elsewhere [15, 16]. These variances in MRSA reporting among S. aureus isolates might be related to changes in circulating clones in a different geography, as well as disparities in infection- prevention measures and antibiotic prescribing trends in different hospital settings.

In this study, there was no substantively significant association between cMLSB resistance and methicillin resistance in S. aureus (chi-square with Yates correction (df = 1, N = 38) = 0.05, p = 0.822, Phi-coefficient = 0.04). Also, there was no substantively significant association between iMLSB resistance and methicillin resistance in S. aureus (chi-square (df = 1, N = 38) = 0.11, p = 0.745, Phi-coefficient = 0.06). Genotyping i.e., detection of the erm genes is considered a superior tool for surveillance of MLSB resistance. But the continuous mutations in erm genes make the use of genotyping tools difficult. Also, the use of such expensive tools in poor resource settings is hypothetical. In contrast, the phenotypic techniques indicate both the presence and expression of the responsible erm gene. The D-zone test is a simple and cheap phenotypic technique using erythromycin and clindamycin discs. This is a phenotypic disc diffusion test recommended by CLSI [29]. The D-zone test relies on the ability of erythromycin to induce resistance against clindamycin. A flattening of the zone of inhibition around the clindamycin disc in the proximity of the erythromycin disc, producing a D-shaped zone of inhibition, is considered a positive D-zone result. This indicates the induction of clindamycin resistance by erythromycin. The D-zone test has a high throughput reporting different types of phenotypic resistance in a single test. This method has a sensitivity of 100% when the distance of two test disk is 15 mm [32].

Globally, AMR is on the rise, particularly in developing countries, like Nepal. Over the counter sale of antibiotics, lack of effective regulations on antibiotics use, incomplete dosing, excessive use of wide-spectrum antibiotics for common infections, and empiric therapy without laboratory diagnosis are all common in developing countries like Nepal. These practices usually cure infections, so most health settings opt for and retain these practices, but in return, these settings act as a factory of resistant mutants. This, in part, is because of a lack of sufficient resources to set up standard laboratory facilities covering all geography, particularly in remote skirts of developing countries like Nepal. AMR is a public health threat that demands urgent attention. Surveillance of this type reports the updated AMR profile of the circulating pathogens in the region, which in turn can be used for formulating policies with strong strategies to check AMR.

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