Epidemiological and Inducible Resistance in Coagulase Negative Staphylococci

Inducible clindamycin resistance among clinical Gram-positive cocci in a tertiary hospital in Niger Republic

Background. Macrolide-induced resistance to clindamycin is a well-described mechanism leading to treatment failure. Herein, we determined the frequency and associated factors of inducible clindamycin resistance in Gram-positive cocci in a tertiary care hospital. Methods. A cross-sectional descriptive study was carried out between January and December 2022. d-tests were performed as recommended by EUCAST 2021 guidelines on 100 non-duplicate clinical isolates of Gram-positive cocci to determine the prevalence of methicillin resistance and inducible clindamycin resistance among the collected isolates. Results. Of the 100 Gram-positive cocci isolates, 56 (56.0%), 17 (17.0%) and 27 (27.0%) were respectively coagulase-negative staphylococci, Staphylococcus aureus and Streptococcus spp. Among Streptococcus spp., Group D Streptococci (15.0%) were the most isolated. Methicillin-resistant Staphylococcus aureus (MRSA) represented nine (53.0%) of the S. aureus isolates. Constitutive (cMLSb) and inducible clindamycin resistance (iMLSb) phenotypes were detected in 36 (36.0%) and 14 (14.0 %) of the isolates, respectively. S. aureus exhibited 38.4% of cMLSb and 13.7% of iMLSb. The result of multivariate analysis showed that age groups, gender, type of samples, provenance, and bacteria, were not significantly associated with Gram-positive cocci iMLSb phenotype. Conclusion. The study reported for the first time a high prevalence of inducible resistance of Gram-positive cocci strains to clindamycin in Niger Republic. This suggests the urgent need for the implementation of regular screening of these isolates and the wise use of clindamycin in clinical practice.

Phenotypic and genotypic characterization of macrolide, lincosamide and streptogramin B resistance among clinical isolates of staphylococci in southwest of Iran

Objective

The present study aimed to determine the phenotypic and genotypic profile of macrolide, lincosamide and streptogramin B (MLS_B) resistance in clinical isolates of staphylococci.

Results

This cross-sectional study was conducted on 164 non-duplicated staphylococci isolates collected during August 2015 to February 2016 from two tertiary care hospitals in Shiraz, southwest of Iran. Of the 164 isolates, 86 erythromycin-resistant isolates consist of 35 Staphylococcus aureus and 51 coagulase negative staphylococci (CoNS) were included in the study. Of the 35 S. aureus, the prevalence of cMLS (constitutive), iMLS (inducible), and MS phenotypes were found 82.9%, 8.6% and 8.6%, respectively. Among 51 CoNS, the frequencies of cMLS, iMLS, and MS phenotypes were detected 66.7%, 11.8% and 21.6%, respectively. Among S. aureus isolates, the predominant genes were ermC in 82.9% isolates, followed by ermA in 57.1% and msrA in 28.6% of isolates. Among CoNS isolates, the most frequent genes were diagnosed ermC in 70.6% isolates followed by msrA in 68.6% and ermA in 11.8% of isolates. In conclusion, regarding the presence of MLS_B resistance in our region, diagnosis of this resistance type on a routine basis in staphylococcal clinical isolates is of particular importance.

Status Report from the Scientific Panel on Antibiotic Use in Dermatology of the American Acne and Rosacea Society: Part 1: Antibiotic Prescribing Patterns, Sources of Antibiotic Exposure, Antibiotic Consumption and Emergence of Antibiotic Resistance, Impact of Alterations in Antibiotic Prescribing, and Clinical Sequelae of Antibiotic Use

Oral and topical antibiotics are commonly prescribed in dermatologie practice, often for noninfectious disorders, such as acne vulgaris and rosacea. Concerns related to antibiotic exposure from both medical and nonmedical sources require that clinicians consider in each case why and how antibiotics are being used and to make appropriate adjustments to limit antibiotic exposure whenever possible. This first article of a three-part series discusses prescribing patterns in dermatology, provides an overview of sources of antibiotic exposure, reviews the relative correlations between the magnitude of antibiotic consumption and emergence of antibiotic resistance patterns, evaluates the impact of alterations in antibiotic prescribing, and discusses the potential relevance and clinical sequelae of antibiotic use, with emphasis on how antibiotics are used in dermatology.