Macrolide, Lincosamide, And Streptogramin B Research Articles

Effect of composting and storage on the microbiome and resistome of cattle manure from a commercial dairy farm in Poland.

Manure from food-producing animals, rich in antibiotic-resistant bacteria and antibiotic resistance genes (ARGs), poses significant environmental and healthcare risks. Despite global efforts, most manure is not adequately processed before use on fields, escalating the spread of antimicrobial resistance. This study examined how different cattle manure treatments, including composting and storage, affect its microbiome and resistome. The changes occurring in the microbiome and resistome of the treated manure samples were compared with those of raw samples by high-throughput qPCR for ARGs tracking and sequencing of the V3-V4 variable region of the 16S rRNA gene to indicate bacterial community composition. We identified 203 ARGs and mobile genetic elements (MGEs) in raw manure. Post-treatment reduced these to 76 in composted and 51 in stored samples. Notably, beta-lactam, cross-resistance to macrolides, lincosamides and streptogramin B (MLSB), and vancomycin resistance genes decreased, while genes linked to MGEs, integrons, and sulfonamide resistance increased after composting. Overall, total resistance gene abundance significantly dropped with both treatments. During composting, the relative abundance of genes was lower midway than at the end. Moreover, higher biodiversity was observed in samples after composting than storage. Our current research shows that both composting and storage effectively reduce ARGs in cattle manure. However, it is challenging to determine which method is superior, as different groups of resistance genes react differently to each treatment, even though a notable overall reduction in ARGs is observed.

An increase in erythromycin resistance in methicillin-susceptible Staphylococcus aureus from blood correlates with the use of macrolide/lincosamide/streptogramin antibiotics. EARS-Net Spain (2004-2020).

To describe and analyse erythromycin resistance trends in blood isolates of Staphylococcus aureus (EARS-Net Spain, 2004-2020) and the association of these trends with the consumption of macrolide, lincosamide, and streptogramin B (MLSB) antibiotics. To assess molecular changes that could be involved in erythromycin resistance trends by whole genome analysis of representative isolates. We collected antibiotic susceptibility data for all first-blood S. aureus isolates in patients from 47 Spanish hospitals according to EARS-Net criteria. MLSB antibiotic consumption was obtained from the Spanish Agency for Medicines and Medical Devices (2008-2020). We sequenced 137 representative isolates for core genome multilocus sequence typing, resistome and virulome analysis. For the 36,612 invasive S. aureus isolates, methicillin resistance decreased from 26.4% in 2004 to 22.4% in 2020. Erythromycin resistance in methicillin-susceptible S. aureus (MSSA) increased from 13.6% in 2004 to 28.9% in 2020 (p < 0.001); however, it decreased from 68.7 to 61.8% (p < 0.0001) in methicillin-resistant S. aureus (MRSA). Total consumption of MLSB antibiotics increased from 2.72 defined daily doses per 1,000 inhabitants per day (DID) in 2014 to 3.24 DID in 2016. By WGS, the macrolide resistance genes detected were erm (59.8%), msrA (46%), and mphC (45.2%). The erm genes were more prevalent in MSSA (44/57, 77.2%) than in MRSA (38/80, 47.5%). Most of the erm genes identified in MSSA after 2013 differed from the predominant ermC gene (17/22, 77.3%), largely because ermT was significantly associated with MSSA after 2013 (11/29, 37.9%). All 13 ermT isolates in this study, except one, belonged to ST398 and came from 10 hospitals and six Spanish provinces. The significant increase in erythromycin resistance in blood MSSA correlated with the consumption of the MLSB antibiotics in Spain. These preliminary data seem support the hypothesis that the human ST398 MSSA clade with ermT-mediated resistance to erythromycin may be involved in this trend.

Distribution of Macrolide, Lincosamide, and Streptogramin B and Detection of erm Genes in Staphylococcus aureus from Wounds in Uyo, Nigeria

The increasing resistance to macrolide, lincosamide, and streptogramin B (MLSB) among methicillin-resistant Staphylococcus aureus (MRSA) is a challenge. The study determined the constitutive and inducible MLSB resistance and erm genes in S. aureus from wounds using the erythromycin-clindamycin D-zone test and a multiplex polymerase chain reaction assay, respectively. Of the 260 patients recruited in the study, S. aureus was isolated from the wounds of 102 patients, giving a prevalence rate of 39.2%. Of the 102 S. aureus isolates, 32.4% were methicillin-sensitive S. aureus (MSSA), and 67.6% were MRSA. The prevalence of S. aureus in wounds was higher in females (39.8%) than in males (38.4%). The highest prevalence of S. aureus was found in divorce patients (59.1%) and those residing in urban areas (39.7%). There was no statistical difference between the occurrence of MRSA and MSSA in wounds based on the sex (p = 0.97), age (p = 0.08), and marital status (p = 0.41) of the patients. All (100%) MRSA were resistant to Cefoxitin, and chloramphenicol, while ˂ 50% of MRSA were resistant to Tetracycline, Ciprofloxacin, and Gentamycin. Of the 69 MRSA isolates from the wounds, 21.7% and 26.1% were iMLSB and cMLSB phenotypes, respectively. Nine (9) MSSA were iMLSB phenotypes, and eight MSSA were cMLSB phenotypes. Among the 12 representative isolates, three (3) MRSA and one (1) MSSA isolate possessed the ermC gene. This study has revealed that screening tests for iMLSB-resistant S. aureus strains are critical for the therapeutic management of wound infections caused by S. aureus.

Genomic Characterization of Fecal Escherichia coli Isolates with Reduced Susceptibility to Beta-Lactam Antimicrobials from Wild Hogs and Coyotes.

This study was carried out to determine the antimicrobial resistance (AMR) genes and mobile genetic elements of 16 Escherichia coli isolates-with reduced susceptibility to ceftazidime and imipenem-that were recovered from the fecal samples of coyotes and wild hogs from West Texas, USA. Whole-genome sequencing data analyses revealed distinct isolates with a unique sequence type and serotype designation. Among 16 isolates, 4 isolates were multidrug resistant, and 5 isolates harbored at least 1 beta-lactamase gene (blaCMY-2, blaCTX-M-55, or blaCTX-M-27) that confers resistance to beta-lactam antimicrobials. Several isolates carried genes conferring resistance to tetracyclines (tet(A), tet(B), and tet(C)), aminoglycosides (aac(3)-IId, ant(3″)-Ia, aph(3')-Ia, aph(3″)-lb, aadA5, and aph(6)-ld), sulfonamides (sul1, sul2, and sul3), amphenicol (floR), trimethoprim (dfrA1 and dfrA17), and macrolide, lincosamide, and streptogramin B (MLSB) agents (Inu(F), erm(B), and mph(A)). Nine isolates showed chromosomal mutations in the promoter region G of ampC beta-lactamase gene, while three isolates showed mutations in gyrA, parC, and parE quinolone resistance-determining regions, which confer resistance to quinolones. We also detected seven incompatibility plasmid groups, with incF being the most common. Different types of virulence genes were detected, including those that enhance bacterial fitness and pathogenicity. One blaCMY-2 positive isolate (O8:H28) from a wild hog was also a Shiga toxin-producing E. coli and was a carrier of the stx2A virulence toxin subtype. We report the detection of blaCMY-2, blaCTX-M-55, and blaCTX-M-27 beta-lactamase genes in E. coli from coyotes for the first time. This study demonstrates the importance of wildlife as reservoirs of important multi-drug-resistant bacteria and provides information for future comparative genomic analysis with the limited literature on antimicrobial resistance dynamics in wildlife such as coyotes.

Occurrence, Antibiotic Susceptibility, Biofilm Formation and Molecular Characterization of Staphylococcus aureus Isolated from Raw Shrimp in China.

The aim of this study was to determine the prevalence and characterization of Staphylococcus aureus isolated from 145 shrimp samples from 39 cities in China. The results show that 41 samples (28%) from 24 cities were positive, and most of the positive samples (39/41, 95.1%) were less than 110 MPN/g. Antimicrobial susceptibility testing showed that only seven isolates were susceptible to all 24 antibiotics, whereas 65.1% were multidrug-resistant. Antibiotic resistance genes that confer resistance to β-lactams, aminoglycosides, tetracycline, macrolides, lincosamides and streptogramin B (MLSB), trimethoprim, fosfomycin and streptothricin antibiotics were detected. All S. aureus isolates had the ability to produce biofilm and harbored most of the biofilm-related genes. Genes encoding one or more of the important virulence factors staphylococcal enterotoxins (sea, seb and sec), toxic shock syndrome toxin 1 (tsst-1) and Panton-Valentine leukocidin (PVL) were detected in 47.6% (30/63) of the S. aureus isolates. Molecular typing showed that ST15-t085 (27.0%, 17/63), ST1-t127 (14.3%, 9/63) and ST188-t189 (11.1%, 7/63) were the dominant genetic types. The finding of this study provides the first comprehensive surveillance on the incidence of S. aureus in raw shrimp in China. Some retained genotypes found in this food have been linked to human infections around the world.

Co-occurrence pattern of ARGs and N-functional genes in the aerobic composting system with initial elevated temperature

Animal manure is known to harbor antibiotic resistance genes (ARGs). Aerobic composting is a prevalent cost-effective and sustainable method to treat animal waste. However, the effect of initially elevated temperature on antibiotic resistome during the composting process is unclear. In this study composting was subjected to initial external heating (EHC) for a period of 5 days compared to conventional composting (CC). After composting ARGs abundance was significantly reduced by 2.43 log in EHC and 1.95 log in CC. Mobile genetic elements (MGEs) also exhibited a reduction of 1.95 log in EHC and 1.49 log in CC. However, during the cooling phase, the genes resisting macrolide lincosamide and streptogramin B (MLSB) rebounded by 0.04 log in CC. The potential human pathogenic bacteria Pseudomonas (41.5–61.5%) and Actinobacteria (98.4–98.8%) were significantly reduced in both treatments and the bulk of targeted antibiotics were eliminated by 80.74% in EHC and 68.98% in CC. ARGs and N-functional genes (NFGs), mainly denitrification genes, were carried by the same microbial species, such as Corynebacterium sp. and Bacillus sp., of the dominant phylum. Redundancy analysis (RDA) revealed that CC microbial communities played a key role in the enrichment of ARGs while in EHC the variation of ARGs was attributed to the composting temperature. The number of high-risk ARGs was also lower in EHC (4) compared with CC (6) on day 30. These results provide insight into the effects of an initially enhanced temperature on ARGs removal and the relationship between ARGs and NFGs during the composting process.

The Plasmidomic Landscape of Clinical Methicillin-Resistant Staphylococcus aureus Isolates from Malaysia.

Methicillin-resistant Staphylococcus aureus (MRSA) is a priority nosocomial pathogen with plasmids playing a crucial role in its genetic adaptability, particularly in the acquisition and spread of antimicrobial resistance. In this study, the genome sequences of 79 MSRA clinical isolates from Terengganu, Malaysia, (obtained between 2016 and 2020) along with an additional 15 Malaysian MRSA genomes from GenBank were analyzed for their plasmid content. The majority (90%, 85/94) of the Malaysian MRSA isolates harbored 1-4 plasmids each. In total, 189 plasmid sequences were identified ranging in size from 2.3 kb to ca. 58 kb, spanning all seven distinctive plasmid replication initiator (replicase) types. Resistance genes (either to antimicrobials, heavy metals, and/or biocides) were found in 74% (140/189) of these plasmids. Small plasmids (<5 kb) were predominant (63.5%, 120/189) with a RepL replicase plasmid harboring the ermC gene that confers resistance to macrolides, lincosamides, and streptogramin B (MLSB) identified in 63 MRSA isolates. A low carriage of conjugative plasmids was observed (n = 2), but the majority (64.5%, 122/189) of the non-conjugative plasmids have mobilizable potential. The results obtained enabled us to gain a rare view of the plasmidomic landscape of Malaysian MRSA isolates and reinforces their importance in the evolution of this pathogen.

Correlation Betveen Erythromycin- Resistance Phenotypes ofStreptoco cc us Pne unrc nifi e ancl the Invitro Activitl' of Telith romycineand Azithrornycine

Tow principal mechanisms have so far been found to be responsible for acquired macrolide ,lincosamide and streptogramin B (MLSB) antibiotics resistance in Streptococcus pneumoniae : target site modification and active drug efflux .the target site modification is due to methylase prevents the binding of the antibiotic to its ribosomal target and can be expressed either in a constitutive (cMLS phenotype) or inducible (iMLS phenotype ) manner .the macrolide efflux system,M phenotype ,is mediated by a membrane protein responsible for the efflux resistance. Although the incidence of resistance to macrolides was low in the past today the incidence reported by several countries shows a sensible increase. Thus it is necessary to search and test novel antimicrobial agents characterized by a spectrum of activity against the most common respiratory pathogens. This study compared the invitro activity (MIC and MBC) of telithromycin with activity of azithromycin against Streptococcus pneumoniae recently isolated from San Giovanni Battista Hospital (Turin, Italy). Erythromycin — resistance phenotypes were determined through a triple — disk test to correlate a potential different bacterial pattern to antimicrobial s sceptibility. The incidence of erythromycin-resistance was 26.66% .In the group of Ery-R Streptococcus pneumoniae 58.33% strains belonged to ¢MLS phenotype, 33.33% to M phenotype and 8.33% to iMLS phenotype. Telithromycin presented MIC values lower than those detected with azithromycin against all isolated strains . Telithromycin appeared to be highly active against Streptococcus pneumoniae, in particular when resistance is mediated by the efflux system confirming its clinical efficacy among respiratory streptococcal infections.

Characteristics of the ErmK Protein of Bacillus halodurans C-125.

Bacillus halodurans C-125 is an alkaliphilic microorganism that grows best at pH 10 to 10.5. B. halodurans C-125 harbors the erm (erythromycin resistance methylase) gene as well as the mphB (macrolide phosphotransferase) and putative mef (macrolide efflux) genes, which confer resistance to macrolide, lincosamide, and streptogramin B (MLSB) antibiotics. The Erm protein expressed in B. halodurans C-125 could be classified as ErmK because it shares 66.2% and 61.2% amino acid sequence identity with the closest ErmD and Erm(34), respectively. ErmK can be regarded as a dimethylase, as evidenced by reverse transcriptase analysis and the antibiotic resistance profile exhibited by E. coli expressing ermK. Although ErmK showed one-third or less in vitro methylating activity compared to ErmC', E. coli cells expressing ErmK exhibited comparable resistance to erythromycin and tylosin, and a similar dimethylation proportion of 23S rRNA due to the higher expression rate in a T7 promoter-mediated expression system. The less efficient methylation activity of ErmK might reflect an adaption to mitigate the fitness cost caused by dimethylation through the Erm protein presumably because B. halodurans C-125 has less probability to encounter the antibiotics in its favorable growth conditions and grows retardedly in neutral environments. IMPORTANCE Erm proteins confer MLSB antibiotic resistance (minimal inhibitory concentration [MIC] value up to 4,096 μg/mL) on microorganisms ranging from antibiotic producers to pathogens, imposing one of the most pressing threats to clinics. Therefore, Erm proteins have long been speculated to be plausible targets for developing inhibitor(s). In our laboratory, it has been noticed that there are variations in enzymatic activity among the Erm proteins, Erm in antibiotic producers being better than that in pathogens. In this study, it has been observed that Erm protein in B. halodurans C-125 extremophile is a novel member of Erm protein and acts more laggardly, compared to that in pathogen. While this sluggishness of Erm protein in extremophile might be evolved to reduce the fitness cost incurred by Erm activity adapting to its environments, this feature could be exploited to develop the more potent and/or efficacious drug to combat formidably problematic antibiotic-resistant pathogens.

Hypoxia triggers the proliferation of antibiotic resistance genes in a marine aquaculture system

The transmission of antibiotic resistance genes (ARGs) affects the safety of aquaculture animals. Dissolved oxygen (DO) can affect the transmission of ARGs, but its mechanism of action in this process is unclear. We conducted laboratory breeding experiment with low and control DO groups. Combined quantitative PCR and 16S rRNA sequencing to study the effect of DO on the spread of ARGs. Hypoxia treatment significantly increased the accumulation of ammonium and nitrite in aquaculture water, and it increased the relative abundances of ARGs and mobile genetic elements (MGEs), especially the ARGs resistant to drugs in the categories of sulfonamide, (flor)/(chlor)/(am)phenicol, and MLSB (macrolide, lincosamide and streptogramin B) and the MGE intI-1(clinic), by 2.39–95.69 % in 28 days relative to the control DO treatment. Though the abundance of ARG carries, especially the Rhodocyclaceae, Caldilineaceae, Cyclobacteriaceae, Saprospiraceae, Enterobacteriaceae, Sphingomonadaceae families, showed higher abundance in low DO groups, relating to the vertical transmission of ARGs. Hypoxia treatment is more likely to promote the horizontal gene transfer (HGT)-related pathways, including ABC transporters, two component system, and quorum sensing, thus to induce the HGT of ARGs. The changed bacterial proliferation also altered the abundance of MGEs, especially intI-1(clinic), which induced HGT of ARGs as well. Additionally, pearson correlation results revealed that the succession of bacterial community function played the strongest role in ARG proliferation, followed by bacterial community structure and MGEs. Our results highlight the importance of suitable DO concentration in controlling the spread of ARGs especially the HGT of ARGs. In the context of global attention to food safety, our results provide important information for ensuring the safety of aquatic products and the sustainable development of aquaculture.

The Array of Antibacterial Action of Protocatechuic Acid Ethyl Ester and Erythromycin on Staphylococcal Strains.

The spread of antibiotic resistance among bacteria has become one of the major health problems worldwide. Methicillin-resistant staphylococcal strains are especially dangerous because they are often resistant to other antibiotics. The increasing insensitivity to macrolides, lincosamides and streptogramin B antibiotics of methicillin-resistant staphylococcal isolates has limited the use of these drugs in therapy. The combination of natural compounds and antibiotics can be considered as an alternative tool to fight multi-drug-resistant pathogen infections. The aim of the presented study was to examine the antibacterial activity of protocatechuic acid ethyl ester–erythromycin combination towards Staphylococcus aureus and Staphylococcus epidermidis strains with various resistance profiles to methicillin and macrolides, lincosamides and streptogramin B (MLSB) antibiotics. The in-vitro antibacterial potential of the above combination was investigated by minimum inhibitory concentration assays and checkerboard testing. The observed effects were strain dependent, with 8 of 12 tested staphylococcal strains showing an indifferent effect on the natural compound and erythromycin; for 2 strains, the tested combination had an additive effect, while for another 2, the effect was synergistic. Interestingly, the multi-drug-resistant strains were more sensitive to the cooperative action of the protocatechuic acid ethyl ester and the antibiotic.

Constitutive and Inducible Clindamycin Resistance Frequencies among Staphylococcus sp. Coagulase Negative Isolates in Al-Basrah Governorate, Iraq.

Antibiotics called macrolide, lincosamide and streptogramin B (MLSB) are being used to treat staphylococci infections. Multiple pathways that impart resistance to MLSB antibiotics have been confirmed to cause clinical failure. The present work aimed to determine the frequency of constitutive and inducible clindamycin resistant among coagulase-negative staphylococci (CoNS) isolates of different clinical samples in Al-Basrah governorate, Iraq. The 28 CoNS, traditional techniques and the Vitek®2 system were used to identify the isolates. The disk diffusion technique was used to detect methicillin resistance and antibiotic sensitivity patterns via cefoxitin, gentamicin, ciprofloxacin, amikacin, teicoplanin, linezolid, doxycycline and vancomycin disks. Erythromycin and clindamycin antibiotic disks was used to detect the inducible and constitutive clindamycin resistance as well as a D-test according to CLSI guidelines. Among 28 CoNS isolated, the Staphylococcus aureus 11(39.29%), Staphylococcus epidermidis 7(25 %), Staphylococcus haemolyticus 4(14.29%) and Staphylococcus saprophyticus 3 (10.71%) were predominant isolated species. Out of 28 CoNS isolates, 15(53.57%) were methicillin resistant coagulase-negative staphylococci (MRCoNS) isolates and 13(46.43%) were methicillin sensitive coagulase-negative staphylococci (MSCoNS) isolates. The 15(53.57%) isolates out of 28 CoNS, showed erythromycin resistance while 6(40%) isolates out of 15 CoNS, showed inducible macrolide-lincosamide-streptogramin B (iMLSB) and 2(13.3%) of CONS isolated showed constitutive macrolide-lincosamide-streptogramin B (cMLSB). In order to achive the best result in choosing the suitable treatment and avoiding the loses the money and time, it is better to use the D-test for inducible clindamycin resistance in the daily routine work of antibiotic susceptibility testing in hospital and private clinical laboratories.

Saccharomyces boulardii CNCM I-745 supplementation modifies the fecal resistome during Helicobacter pylori eradication therapy.

The gut microbiota is a significant reservoir of antimicrobial resistance genes (ARGs). The use and misuse of antimicrobials can select multi-resistant bacteria and modify the repertoire of ARGs in the gut. Developing effective interventions to manipulate the intestinal resistome would allow us to modify the antimicrobial resistance risk. Applying shotgun metagenomics, we compared the composition of fecal resistome from individuals treated with triple therapy for Helicobacter pylori plus Saccharomyces boulardii CNCM-I 745 (Sb) versus triple antibiotherapy without S. boulardii (control) before, after, and one month after treatments. DNA samples were sequenced on an Illumina NovaSeq 6000 platform. Reads were trimmed and filtered for quality, and the reads classified as host genome were removed from further analysis. We used the ResFinder database for resistome analysis and the web-based tool ResistoXplorer and RStudio for graphical representation and statistical analysis. We identified 641 unique ARGs in all fecal samples, conferring resistance to 18classes of antibiotics. The most prevalent ARGs found in at least 90% of the samples before the treatments were against tetracyclines, MLS-B (macrolide, lincosamide, and streptogramin B), beta-lactams, and aminoglycosides. Differential abundance analysis allowed the identification of ARGs significantly different between treatment groups. Thus, immediately after the treatments, the abundance of ARGs that confer resistance to lincosamides, tetracyclines, MLS-B, and two genes in the beta-lactam class (cfxA2 and cfxA3) was significantly lower in the group that received Sb than in the control group (edgeR, FDR <0.05). Our study demonstrated that the addition of S. boulardii CNCM-I 745 to the conventional antibiotic eradication therapy for H. pylori reduced the abundance of ARGs, particularly those genes that confer resistance to lincosamides, tetracyclines, MLS-B, and a few genes in the beta-lactams class.

Mechanisms of Resistance to Macrolide Antibiotics among Staphylococcus aureus.

Methicillin resistant Staphylococcus aureus strains pose a serious treatment problem because of their multi-drug resistance (MDR). In staphylococcal strains, resistance to macrolides, lincosamides, and streptogramin B (MLSB) correlates with resistance to methicillin. The rapid transmission of erm genes responsible for MLSB resistance has strongly limited the clinical application of traditional macrolides such as erythromycin. On the other hand, in the age of increasing insensitivity to antibiotics the idea of implementing a therapy based on older generation drugs brings hope that the spread of antibiotic resistance will be limited. A thorough understanding of the resistance mechanisms contributes to design of antibiotics that avoid bacterial insensitivity. This review highlights the mechanisms of action of macrolides and mechanism of resistance to these antibiotics among Staphylococcus aureus.

Genetic characterization of two methicillin-resistant Staphylococcus aureus spa type t127 strains isolated from workers in the dairy production chain in Greece.

Methicillin-resistant Staphylococcus aureus (MRSA) constitutes a constant threat for the public health. Aim of the present study was to analyse the whole genome sequences of two MRSA strains belonging to Staphylococcus protein A (spa) type t127 isolated from humans working in two distantly located dairy production farms in Greece.MRSA strains were isolated from the nasal cavity of a food handler in a milk industry in Epirus, northwestern Greece (E-MRSA), and a person working in a cattle farm in Thrace, northeastern Greece (T-MRSA). Whole genome sequences taken using next generation sequencing were analysed for resistance and virulence genes applying various bioinformatic tools.Both isolates were assigned to ST1-IVa-t127 type, and they were transferring genes conferring resistance to tetracycline, β-lactams, and aminoglycosides; T-MRSA was carrying additional genes leading to macrolide, lincosamide and streptogramin B (MLSB) resistance. Both isolates were carrying three plasmid replicon types, rep5, rep7 and rep16, while T-MRSA harboured also rep10 and rep15. E-MRSA carried scn and sak genes which were absent from T-MRSA.In conclusion, the genetic characterization of two unrelated ST1-IVa-t127 MRSA strains isolated from humans in close contact with livestock in Greece can be used as basis for further epidemiological and evolutionary studies.

Antibiotic Sensitivity to Methicillin and Methicillin Plus Macrolide- Lincosamide-Streptogramins Resistant Staphylococcus Aureus

This study was conducted from May 2018 to Oct 2019 to determine the culture and sensitivity pattern of Methicillin resistant Staphylococcus aureus (MRSA) and MRSA with Macrolide Lincosamide and Streptogramin-B (MLS-B) antibiotics in a tertiary care hospital of Nowshera. A total of 235 isolates were studies and 86 samples showed MRSA. The prevalence rate of MRSA was 89/235 (37.87%). Out of 86 isolates with MRSA, 19 (22.09%) were also resistant to MLS-B antibiotics.Regarding gender specification, 52 (60.5%) were females and 34 (39.5%) were males. The mean age with standard deviation of patients was 29 + 6.8 years. The sensitivity pattern to MRSA was; Vancomycin 100%, Linezolid 100%, Rifampicin 86.04%, Clindamycin, 73.25%, Fusidic acid 60.46%, Erythromycin 44.18%., Doxycyclin 32.55%, levofloxacin 16.27%, Gentamycin 13.95% and Ciprofloxacin 11. 62%. Sensitivity of Vancomycin &amp; Linezolid was 100% in MRSA and MLS-B resistant isolates, and should be kept reserved for MRSA cases to avoid misuse of antibiotics and to reduce resistance.

Distance dilution of antibiotic resistance genes of sediments in an estuary system in relation to coastal cities

Coastal tourist and industrial cities are most likely to have differential effects on the distance dilution of antibiotic resistance genes (ARGs) in an estuary system. This study used high-throughput fluorescence quantitative polymerase chain reaction to identify sediment ARGs in two typical estuaries of coastal tourist and industrial cities (Xiamen and Taizhou) in China. The distance dilution of ARGs and its relationship with key environmental factors were analysed. The results indicated that along the river inlet towards the sea, the distance dilution effect on ARG abundance in estuary sediments of Taizhou was approximately double that in Xiamen, and the macrolide, lincosamide, and streptogramin B (MLSB) and vancomycin genes were replaced by the fluoroquinolone, quinolone, florfenicol, chloramphenicol, and amphenicol (FCA) and β-lactam genes in Taizhou, whereas β-lactam genes succeeded the MLSB and sul genes in Xiamen. The abundance and number of ARGs and mobile genetic elements (MGEs) were positively correlated with the particle size and total organic carbon (TOC) contents of sediments, whereas they were negatively associated with the oxidation and reduction potential (Eh) and pH of sediments, as well as the seawater salinity. The sediment particle size (SPZ) was the dominant physicochemical factor affecting the abundance of ARGs (r = 0.826, p < 0.05) and MGEs (r = 0.850, p < 0.01). These findings suggest that although the distance dilution effect on the ARG abundance of estuary sediments of the industrial city is greater than that of the tourist city, the larger SPZ, higher TOC content, and lower salinity, pH, and Eh in estuary regions adjacent to the industrial city can more significantly facilitate the proliferation and propagation of ARGs in the sediments.

Prevalence of Inducible Clindamycin Resistance in Staphylococcus: A Study from a Rural Teaching Tertiary Care Hospital in Southern Haryana

Introduction: Clindamycin is the most commonly prescribed Macrolides, Lincosamides and Streptogramin-B (MLSB) antibiotics to treat staphylococcal infections. It has excellent pharmacokinetic properties. Staphylococcus species shows either constitutive (MLSBc) or inducible (MLSBi) clindamycin resistance. Routine D-test recommended by Clinical Laboratory and Standard Institute (CLSI) can detect MLSBi phenotype and prevent treatment failure. Aim: To identify inducible clindamycin resistance in Staphylococci in a rural teaching Tertiary Care Hospital. Materials and Methods: It was a prospective, cross-sectional study. The clinical samples were cultured on blood agar and MacConkey agar. Staphylococcus isolates were identified based on their colony characteristics, gram stain and standard biochemical test. Antimicrobial susceptibility test was performed by Kirby Bauer’s disc diffusion method. To detect Methicillin resistance Cefoxitin disc (30 μg) was used. The isolates that were Erythromycin resistant and Clindamycin sensitive were further subjected to D test. CLSI 2019 guidelines were followed for performing the tests and its interpretation. Epi-info (version 7.2.3.1) Centre for Disease Control and Prevention (CDC), Atlanta, Georgia was used to analyse the data and interpretation of the results. Results: Total 150 Staphylococci were isolated from different samples. Staphylococcus aureus were 70% and Coagulase negative Staphylococcus (CoNS) were 30%. Pus was the most common specimen from which 43% Staphylococci was isolated. Sensitivity to vancomycin and linezolid were 100%. Staphylococcus aureus (38%) and CoNS (33%) were Methicillin resistant. Overall (63%) of staphylococcus isolates were resistant to erythromycin. The different susceptibility patterns to clindamycin in both Staphylococcus aureus and CoNS were noted. MLSBc phenotype was most prevalent (37.3%) followed by MS (13.4%) and MLSBi (12%) among erythromycin resistant Staphylococcus isolate. Sensitive (S) phenotype was detected in 56 (37%). MLSBi was more frequent in Methicillin Resistant Staphylococcus aureus (MRSA) (23%) and MRCoNS (27%) than in MSSA (5%) and MSCoNS (7%). Conclusion: D-test should be performed routinely to avoid false susceptible results leading to treatment failure.

Molecular Characterization of Hospital- and Community-Acquired Streptococcus agalactiae Isolates among Nonpregnant Adults in Isfahan, Iran.

Background:The increasing incidence of Group B Streptococcus (GBS) infection among nonpregnant adults has become of growing clinical and public health concern. The current study investigated the distribution of important virulence determinants and antibiotic susceptibility of GBS isolates causing community acquired (CA) and hospital acquired (HA) infections among nonpregnant adults.Materials and Methods:A total of 62 GBS, including 31 CA GBS and 31 HA GBS, were collected from a teaching hospital in Isfahan, Iran. Capsular polysaccharide genotypes (CPS), PI 1, PI 2a, PI 2b, and hypervirulent GBS adhesin (hvgA) virulence genes and antibiotic resistance profiling were determined.Results:There were 19 (30.6%) cases of underlying disease that diabetes mellitus (20.9%) was most common. The rate of multidrug resistant GBS strains was accounted for 29%. Distribution of macrolide resistant phenotypes was as follows: constitutive macrolides, lincosamides, and streptogramin B (MLSB) (15 isolates); inducible resistance to MLSB; and L phenotype (each 5 isolates) and M phenotype (1 isolate). V and Ia serotypes were the most predominant capsular type in HA GBS and CA GBS isolates, respectively. The most frequent pilus types were PI 1, PI 1+PI 2a, PI 1+PI 2b, and PI 2a. PI 1 and PI 1+PI 2a had significantly different distributions between CA and HA GBS isolates. Three CA GBS isolates (9.6%) were positive for hvgA gene that belonged to clonal complex 17/sequence type 17/CPS III/PI 1+PI 2b lineage.Conclusion:There was a significant difference in the distribution of PIs among CA GBS and HA GBS isolates in our region.

Helcococcus kunzii methyltransferase Erm(47) responsible for MLSB resistance is induced by diverse ribosome-targeting antibiotics.

To determine the mechanism of induction of erm(47) and its atypical expression in the Gram-positive opportunistic pathogen Helcococcus kunzii, where it confers resistance to a subset of clinically important macrolide, lincosamide and streptogramin B (MLSB) antibiotics. The resistant H. kunzii clinical isolate UCN99 was challenged with subinhibitory concentrations of a wide range of ribosome-targeting drugs. The methylation status of the H. kunzii ribosomal RNA at the MLSB binding site was then determined using an MS approach and was correlated with any increase in resistance to the drugs. The H. kunzii erm(47) gene encodes a monomethyltransferase. Expression is induced by subinhibitory concentrations of the macrolide erythromycin, as is common for many erm genes, and surprisingly also by 16-membered macrolide, lincosamide, streptogramin, ketolide, chloramphenicol and linezolid antibiotics, all of which target the 50S ribosomal subunit. No induction was detected with spectinomycin, which targets the 30S subunit. The structure of the erm(47) leader sequence functions as a hair trigger for the induction mechanism that expresses resistance. Consequently, translation of the erm(47) mRNA is tripped by MLSB compounds and also by drugs that target the 50S ribosomal subunit outside the MLSB site. Expression of erm(47) thus extends previous assumptions about how erm genes can be induced.