Multi-drug resistance traits of methicillin-resistant Staphylococcus aureus and other Staphylococcal species from clinical and environmental sources

Bacterial isolates from drinking water river sources exhibit multi-drug resistant trait

Freshwater habitat is a natural reservoir for antimicrobial resistance (AMR). AMR poses serious human, animal, and environmental public health threats. This study aimed to evaluate the physicochemical and microbiological quality of five selected rivers (Apitipiti 1, Apitipiti 2, Apitipiti 3, Sogidi, and Aba Apa Akinmorin) in Oyo town, Nigeria, as well as the antibiotic resistance pattern of isolated bacterial species, using conventional methods. Most physicochemical parameters were within WHO and NIS permissible limits. Pearson's correlation matrix indicated that there were significant (p < 0.05) interactions among pH, electrical conductivity, temperature, sulphate and chloride salts, and BOD and COD. A total of thirty-two (32) bacterial species were isolated and identified as: Aeromonas (9), Bacillus (2), Corynebacterium (13), Lactobacillus (1), Pseudomonas (2), Staphylococcus (4), and Streptococcus (1). Of the rivers, Sogidi had the highest microbial load (6.36 log CFU/mL) while Apititipiti 1 had the lowest (5.76 log CFU/mL). With regard to antibiotic sensitivity, 81.8% were multidrug-resistant, with Corynebacterium kutscheri and Aeromonas spp. isolated from Apitipiti 2 and Aba Apa Akinmorin rivers, respectively, exhibiting a relatively high antibiotic resistance of 90.9%. This study reveals that these rivers may be unfit for consumption as multidrug-resistant bacteria of public health risk were associated with them.

Microbiological and Molecular Investigation of Antimicrobial Resistance in Staphylococcus aureus Isolates from Western Romanian Dairy Farms: An Epidemiological Approach

Antimicrobial therapy is the most frequently used medical intervention for bovine mastitis in the dairy industry. This study aims to monitor the extent of the antimicrobial resistance (AMR) problem in Staphylococcus aureus in the dairy industry in Western Romania. Twenty farms were selected by random sampling in a transverse epidemiological study conducted across four counties in Western Romania and divided into livestock units. This study assessed the association between the resistance genes to phenotypic expression of resistance and susceptibility. Isolates of S. aureus were identified and q-PCR reactions were used to detect antibiotic resistance genes. One hundred and fifty bovine and 20 human samples were positive for S. aureus. Twenty five percent of bovine isolates (30/120) and none(0/30) of the human isolates were methicillin-resistant S. aureus (MRSA). All isolates were susceptible to fosfomycin, ciprofloxacin, netilmicin, and resistant to ampicillin and penicillin. S. aureus isolates regarded as phenotypically resistant (R) were influenced by the origin of the samples (human versus bovine, χ2 = 36.510, p = 0.013), whether they were methicillin-resistant S. aureus (χ2 = 108.891, p < 0.000), the county (χ2 = 103.282, p < 0.000) and farm of isolation (χ2 = 740.841, p < 0.000), but not by the size of the farm (χ2 = 65.036, p = 0.306). The multiple antibiotic resistance index was calculated for each sample as the number regarded as phenotypically resistant (R)/total antibiotics tested (MARI = 0.590 ± 0.023) was significantly higher (p < 0.000) inmethicillin-resistant S. aureus (0.898 ± 0.019) than non-methicillin-resistant S. aureus (0.524 ± 0.024) isolates. For the antibiotics tested, the total penetrance (P%) of the resistance genes was 59%, 83% for blaZ, 56% for cfr, 50% for erm(B), 53% for erm(C), 57% for mecA and 32% for tet(K). Penetrance can be used as a parameter for guidance towards a more accurate targeting of chemotherapy. P% in S. aureus was strongly positively correlated with the multiple antibiotic resistance index (r = +0.878, p < 0.000) with the potential to use the same limit value as an antibiotic management decision criterion. Considering cow mastitis, the penetrance value combined with the multiple antibiotic resistance index suggests that penetrance could serve as a useful parameter for more precise targeting of chemotherapy for S. aureus.

Advancements in Synthetic Strategies and Biological Effects of Ciprofloxacin Derivatives: A Review

Ciprofloxacin is a widely used antibiotic in the fluoroquinolone class. It is widely acknowledged by various researchers worldwide, and it has been documented to have a broad range of other pharmacological activities, such as anticancer, antiviral, antimalarial activities, etc. Researchers have been exploring the synthesis of ciprofloxacin derivatives with enhanced biological activities or tailored capability to target specific pathogens. The various biological activities of some of the most potent and promising ciprofloxacin derivatives, as well as the synthetic strategies used to develop them, are thoroughly reviewed in this paper. Modification of ciprofloxacin via 4-oxo-3-carboxylic acid resulted in derivatives with reduced efficacy against bacterial strains. Hybrid molecules containing ciprofloxacin scaffolds displayed promising biological effects. The current review paper provides reported findings on the development of novel ciprofloxacin-based molecules with enhanced potency and intended therapeutic activities which will be of great interest to medicinal chemists.

Hydrogen peroxide preoxidation as a strategy for enhanced antimicrobial photodynamic action against methicillin-resistant Staphylococcus aureus

Antimicrobial photodynamic treatment (aPDT) is a photooxidative process based on the excitation of a photosensitizer (PS) in the presence of molecular oxygen, under specific wavelengths of light. It is a promising method for advanced treatment of water and wastewater, particularly targeting disinfection challenges, such as antibiotic-resistant bacteria (ARB). Research in improved aPDT has been exploring new PS materials, and additives in general. Hydrogen peroxide (H2O2) a widely applied disinfectant, mostly in the food industry and clinical settings, present environmentally negligible residuals at the usually applied concentrations, making it friendly for the water and wastewater sectors. Here, we explored the effects of preoxidation with H2O2 followed by blue light-mediated (450 nm) aPDT using curcumin (a natural-based PS) against methicillin-resistant Staphylococcus aureus (MRSA). Results of the sequential treatment pointed to a slight hampering in aPDT efficiency at very low H2O2 concentrations, followed by an increasing cooperative effect up to a deleterious point (≥7 log10 inactivation in CFU mL-1), suggesting a synergistic interaction of preoxidation and aPDT. The increased performance in H2O2-pretreated aPDT encourages studies of optimal operational conditions for the assisted technology and describes potentials for using the described strategy to tackle the issue of ARB spread.

Detection of mecA positive staphylococcal species in a wastewater treatment plant in South Africa

We investigated the prevalence of antibiotic resistant staphylococci and detection of resistant, virulence, and Spa genes in a South African wastewater treatment plant. Species identified were Staphylococcus aureus, S. lentus, S. arlettae, S. cohnii, S. haemolyticus, S. nepalensis, S. sciuri (now Mammaliicoccus sciuri), and S. xylosus. Isolates showed high resistance to methicillin (91%), ampicillin (89%), ciprofloxacin (86%), amoxycillin (80%), ceftazidime (74%), and cloxacillin (71%). Multiple antibiotic resistance (MAR) index for the isolates exceeded 0.2 (0.50-0.70). Among the isolates, 77% were mecA-positive. All S. aureus strains were positive for nuc and 7 Spa gene types. The present study highlights possibility of treated wastewaters being potential reservoir for antibiotic-resistant staphylococci. This is a cause for concern as wastewater effluents are decanted into environmental waters and these are, in many cases, used for various purposes including recreation (full contact), religious (full body submersion), and drinking water for some rural communities and water for livestock.

A meta-analysis on the prevalence of resistance of Staphylococcus aureus to different antibiotics in Nigeria

BACKGROUND

Rapid emergence of multidrug resistant Staphylococcus aureus has resulted to difficulty in treatment of infections caused by such strains. The aim of this meta-analysis study was to determine the pooled prevalence of resistance of S. aureus to different antibiotics in Nigeria.

METHODS

Literature search for studies was done using Google scholar, PubMed, Science direct, and African Journal Online. The prevalence of S. aureus resistance to different antibiotics was evaluated using the meta-analysis proportion command in MedCalc software version 20.0 adopting a rand effect model. I² statistic and Egger test in MedCalc was used to evaluate the heterogeneity and the presence of publication bias among studies respectively.

RESULTS

A total of 40, 682 studies were retrieved through the database search of which 98 studies met the study inclusion criteria. Prevalence of resistance of S. aureus to different antibiotics ranges from 13 to 82%. Results showed a very high degree of resistance to penicillin G (82% [95% confidence interval (CI) 61%, 0.96%]), cloxacillin (77% [95% CI 64%, 88%]), amoxacillin (74% [95% CI 66%, 81%]), cefuroxime (69% [95% CI 51%, 85%]), ampicillin (68% [95% CI 53%, 81%]). Moderately resistance to erythromycin (47% [95% CI 40%, 53%]), chloramphenicol (47% [95% CI 37%, 56%]), methicillin (46% [95% CI 37%, 56%]), ofloxacin (24% [95% CI 18%, 31%]) and rifampicin 24% [95% CI 6%, 48%]). Low resistance was observed in vancomycin 13% (95% CI 7%, 21%). For each individual meta-analysis, high heterogeneity was observed with I² range (79.36-98.60%) at p-values ≤ 0.01). Egger's tests for regression intercept in funnel plots indicated no evidence of publication bias.

CONCLUSION

This meta-analysis study established that S. aureus in Nigeria has developed resistance to commonly used antibiotics such as the beta-lactam class antibiotics, sulphonamides, tetracyclines, chloramphenicol, and vancomycin. Hence it is imperative to develop programs to promote rational use of antimicrobial agents, infection prevention and control to reduce the incidence of antimicrobial resistance.

A Multi-Omics Study of Familial Lung Cancer: Microbiome and Host Gene Expression Patterns

Background

Inherited susceptibility and environmental carcinogens are crucial players in lung cancer etiology. The lung microbiome is getting rising attention in carcinogenesis. The present work sought to investigate the microbiome in lung cancer patients affected by familial lung cancer (FLC) and indoor air pollution (IAP); and further, to compare host gene expression patterns with their microbiome for potential links.

Methods

Tissue sample pairs (cancer and adjacent nonmalignant tissue) were used for 16S rRNA (microbiome) and RNA-seq (host gene expression). Subgroup microbiome diversities and their matched gene expression patterns were analyzed. Significantly enriched taxa were screened out, based on different clinicopathologic characteristics.

Results

Our FLC microbiome seemed to be smaller, low-diversity, and inactive to change; we noted microbiome differences in gender, age, blood type, anatomy site, histology type, TNM stage as well as IAP and smoking conditions. We also found smoking and IAP dramatically decreased specific-OTU biodiversity, especially in normal lung tissue. Intriguingly, enriched microbes were in three categories: opportunistic pathogens, probiotics, and pollutant-detoxication microbes; this third category involved Sphingomonas, Sphingopyxis, etc. which help degrade pollutants, but may also cause epithelial damage and chronic inflammation. RNA-seq highlighted IL17, Ras, MAPK, and Notch pathways, which are associated with carcinogenesis and compromised immune system.

Conclusions

The lung microbiome can play vital roles in carcinogenesis. FLC and IAP subjects were affected by fragile lung epithelium, vulnerable host-microbes equilibrium, and dysregulated immune surveillance and response. Our findings provided useful information to study the triple interplay among environmental carcinogens, population genetic background, and diversified lung microbiome.

Antibiofilm activity of Cutibacterium acnes cell-free conditioned media against Staphylococcus spp

Staphylococcus spp. and Cutibacterium acnes are members of the skin microbiome but can also act as pathogens. Particularly, Staphylococcus species are known to cause medical devices-associated infections, and biofilm production is one of their main virulence factors. Biofilms allow bacteria to adhere and persist on surfaces, protecting them from antimicrobials and host defenses. Since both bacteria are found in the human skin, potentially competing for niches, we aimed to investigate if C. acnes produces molecules that affect Staphylococcus spp. biofilm formation and dispersal. Thus, we evaluated the impact of C. acnes cell-free conditioned media (CFCM) on S. aureus, S. epidermidis, S. hominis, and S. lugdunensis biofilm formation. S. lugdunensis and S. hominis biofilm formation was significantly reduced with C. acnes CFCM without impact on their planktonic growth. C. acnes CFCM also significantly disrupted S. hominis established biofilms. The active molecules against S. lugdunensis and S. hominis biofilms appeared to be distinct since initial characterization points to different sizes and sensitivity to sodium metaperiodate, although the activity is highly resistant to heat in both cases. Mass spectrometry analysis of the fractions active against S. hominis revealed several potential candidates. Investigating how species present in the same environment interact, affecting the dynamics of biofilm formation, may reveal clinically useful compounds as well as molecular aspects of interspecies interactions.

Lippia graveolens HBK oleoresins, extracted by supercritical fluids, showed bactericidal activity against multidrug resistance Enterococcus faecalis and Staphylococcus aureus strains

OBJECTIVE

The aim of this work was to characterize Lippia graveolens oleoresins, obtained by Supercritical Fluid Extraction (SFE), from crops collected at different locations in Mexico. The antimicrobial effect of oleoresins was tested in reference strains and clinical isolates of susceptible and multidrug resistant (MDR) strains of Enterococcus faecalis and Staphylococcus aureus.

SIGNIFICANCE

The increasing of MDR strains is becoming a global public health problem that has led to the search for new treatments, and essential oils have resurged as a source of compounds with bactericidal functions. Oregano essential oil has attracted attention recently, however, this oil is mainly obtained by hydro-distillation (uses large amounts of water) or solvents extraction (potential contaminant). SFE has gained popularity as it represents an environmentally friendly technology.

METHODS

L. graveolens oleoresins were obtained by SFE, total phenol contents were quantified by Folin-Ciocalteu method, the identification of compounds and thymol and carvacrol quantification was carried out by GC-MS. The antimicrobial activity was tested by minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC).

RESULTS

SFE showed higher yields compared with the hydro-distillation process. L. graveolens grown in different Mexican locations showed differences in oleoresin composition and a slightly different antimicrobial capacity against clinical isolates.

CONCLUSIONS

It was demonstrated that SFE is an efficient technology for extracting L. graveolens oleoresins. Additionally, the solvent-free extraction method and the observed antimicrobial effect, increases the applications of these oleoresins in fields such as cosmetics, food industry, medicine, amongst others.

Occurrence of Multidrug-Resistant Staphylococcus aureus among Humans, Rodents, Chickens, and Household Soils in Karatu, Northern Tanzania

We conducted this study to investigate the isolation frequency and phenotypic antibiotic resistance pattern of Staphylococcus aureus isolated from rodents, chickens, humans, and household soils. Specimens were plated onto mannitol salt agar (Oxoid, Basingstoke, UK) and incubated aerobically at 37 °C for 24 h. Presumptive colonies of S. aureus were subjected to Gram staining, as well as catalase, deoxyribonuclease (DNAse), and coagulase tests for identification. Antibiotic susceptibility testing was performed by using the Kirby-Bauer disc diffusion method on Mueller-Hinton agar (Oxoid, Basingstoke, UK). The antibiotics tested were tetracycline (30 μg), erythromycin (15 μg), gentamicin (10 μg), ciprofloxacin (5 μg), clindamycin (2 μg), and amoxicillin-clavulanate (20 μg/10 μg). The S. aureus strain American Type Culture Collection (ATCC) 25,923 was used as the standard organism. We found that 483 out of 956 (50.2%) samples were positive for S. aureus. The isolation frequencies varied significantly between samples sources, being 52.1%, 66.5%, 74.3%, and 24.5%, respectively, in chickens, humans, rodents, and soil samples (p < 0.001). S. aureus isolates had high resistance against clindamycin (51.0%), erythromycin (50.9%), and tetracycline (62.5%). The overall prevalence of multidrug-resistant (MDR) S. aureus isolates was 30.2%, with 8.7% resistant to at least four different classes of antibiotics.

Analysis of Genome Sequences of Coagulase-Negative Staphylococci Isolates from South Africa and Nigeria Highlighted Environmentally Driven Heterogeneity

Here, we report high-quality annotated draft genomes of eight coagulase-negative staphylococci (CoNS) isolates obtained from South Africa and Nigeria. We explored the prevalence of antibiotic resistance and virulence genes, their association with mobile genetic elements. The pan-genomic analysis highlighted the environmentally driven heterogeneity of the isolates. Isolates from Nigeria had at least one gene for cadmium resistance/tolerance, these genes were not detected in isolates from South Africa. In contrast, isolates from South Africa had a tetM gene, which was not detected among the isolates from Nigeria. The observed genomic heterogeneity correlates with anthropogenic activities in the area where the isolates were collected. Moreover, the isolates used in this study possess an open pan-genome, which could easily explain the environmentally driven heterogeneity.

Diversity and genetic lineages of environmental staphylococci: a surface water overview

Antimicrobial resistance in the environmental dimension is one of the greatest challenges and emerging threats. The presence of resistant bacteria and resistance genes in the environment, especially in aquatic systems, has been a matter of growing concern in the past decade. Monitoring the presence of antimicrobial resistance species, in this particular case, Staphylococcus spp., in natural water environments could lead to a better understanding of the epidemiology of staphylococci infections. Thus, the investigation of natural waters as a potential reservoir and vehicle for transmission of these bacteria is imperative. Only a few studies have investigated the prevalence, antimicrobial resistance and genetic lineages of staphylococci in natural waters. Those studies reported a high diversity of staphylococci species and lineages in surface waters. Methicillin-resistant S. aureus were relatively prevalent in surface waters and, as expected, often presented a multidrug-resistant profile. There was a high diversity of S. aureus lineages in surface waters. The presence of S. aureus CC8 and CC5 suggests a human origin. Among the coagulase-negative staphylococci, the most frequently found in natural waters was S. warneri and S. epidermidis. These studies are extremely important to estimate the contribution of the aquatic environment in the spread of pathogenic bacteria.

Antibiotic-resistant staphylococci from the wastewater treatment plant and grey-water samples in Obafemi Awolowo University, Ile-Ife, Nigeria

This study examined the occurrence and molecular basis for antibiotic-resistant staphylococci from the wastewater treatment plant and grey-water samples in Obafemi Awolowo University, Nigeria. Standard microbiological techniques and molecular methods were utilized. The species identified (MALDI score >1.7) comprised S. saprophyticus (19), S. cohnii (8), S. sciuri (7), S. aureus (4), S. epidermidis (3), S. warneri (2), S. equorum (1), S. haemolyticus (1), S. nepalensis (1), S. condimenti (1), and S. pasteuri (1). Resistance to trimethoprim, tetracycline and cefoxitin were observed in 78.3% (47/60), 36.7% (22/60) and 25% (15/60) of the isolates, respectively. The rate of multidrug resistance was 53.3% (32/60) and observed in eight species from different sampling sites. Seven (S. sciuri; n = 5; S. aureus; n = 1; S. warneri; n = 1) of the 20 selected (representing the various staphylococcal species and antibiotypes) isolates were mecA-positive. Furthermore, the tetK gene was detected in nine isolates, six with dfrA, and four were positive for the dfrG gene. One S. aureus was mecA, tetK and dfrG gene positive. The study provides insights on antibiotic-resistant staphylococci from a non-clinical setting and highlights the need for active surveillance to understand the burden of antimicrobial resistance in Nigeria. This is key to improve synergy across the human, animal and environmental health sectors in Nigeria.