Antibiotic susceptibilities of enterococcus species isolated from hospital and domestic wastewater effluents in alice, eastern cape province of South Africa

Multidrug-Resistant Staphylococcus sp. and Enterococcus sp. in Municipal and Hospital Wastewater: A Longitudinal Study

The objective of the study was to detect multidrug-resistant Staphylococcus sp. and Enterococcus sp. isolates in municipal and hospital wastewater and to determine their elimination or persistence after wastewater treatment. Between August 2021 and September 2022, raw and treated wastewater samples were collected at two hospital and two community wastewater treatment plants (WWTPs). In each season of the year, two treated and two raw wastewater samples were collected in duplicate at each of the WWTPs studied. Screening and presumptive identification of staphylococci and enterococci was performed using chromoagars, and identification was performed with the Matrix Assisted Laser Desorption Ionization Time of Flight mass spectrometry (MALDI-TOF MS®). Antimicrobial susceptibility was performed using VITEK 2® automated system. There were 56 wastewater samples obtained during the study period. A total of 182 Staphylococcus sp. and 248 Enterococcus sp. were identified. The highest frequency of Staphylococcus sp. isolation was in spring and summer (n = 129, 70.8%), and for Enterococcus sp. it was in autumn and winter (n = 143, 57.7%). Sixteen isolates of Staphylococcus sp. and sixty-three of Enterococcus sp. persisted during WWTP treatments. Thirteen species of staphylococci and seven species of enterococci were identified. Thirty-one isolates of Staphylococcus sp. and ninety-four of Enterococcus sp. were multidrug-resistant. Resistance to vancomycin (1.1%), linezolid (2.7%), and daptomycin (8.2%/10.9%%), and a lower susceptibility to tigecycline (2.7%), was observed. This study evidences the presence of Staphylococcus sp. and Enterococcus sp. resistant to antibiotics of last choice of clinical treatment, in community and hospital wastewater and their ability to survive WWTP treatment systems.

Removal of pharmaceutical contaminants from hospital wastewater using constructed wetlands: a review

AbstractPharmaceutical compounds are a significant source of environmental pollution, particularly in hospital wastewater, which contains high concentrations of such compounds. Constructed wetlands have emerged as a promising approach to removing pharmaceutical compounds from wastewater. This paper aims to review the current state of knowledge on the removal of pharmaceutical compounds from hospital wastewater using constructed wetlands, including the mechanism of removal, removal efficiency, and future prospects. Pharmaceutical contaminants have been considered to be one of the most emerging pollutants in recent years. In this review article, various studies on constructed wetlands are incorporated in order to remove the pharmaceutical contaminants. The nature of constructed wetland can be explained by understanding the types of constructed wetland, characteristics of hospital wastewater, removal mechanism, and removal efficiency. The results of the review indicate that constructed wetlands are effective in removing pharmaceutical compounds from hospital wastewater. The removal mechanism of these compounds involves a combination of physical, chemical, and biological processes, including adsorption, degradation, and uptake by wetland plants. The removal efficiency of constructed wetlands varies depending on several factors, including the type and concentration of pharmaceutical compounds, the design of the wetland system, and the environmental conditions. Further research is necessary to optimize the performance of these systems, particularly in the removal of emerging contaminants, to ensure their effectiveness and long-term sustainability.

Antibiotic resistance and virulence potentials of E. faecalis and E. faecium in hospital wastewater: a case study in Ardabil, Iran

Hospital wastewater can contaminate the environment with antibiotic-resistant and virulent bacteria. We analyzed wastewater samples from four hospitals in Ardabil province, Iran for Enterococcus faecium and Enterococcus faecalis using culture and molecular methods. We also performed antimicrobial susceptibility testing and polymerase chain reaction testing for resistance and virulence genes. Out of 141 enterococci isolates, 68.8% were E. faecium and 23.4% were E. faecalis. Ciprofloxacin and rifampicin showed the highest level of resistance against E. faecalis and E. faecium isolates at 65%. High-level gentamicin resistance (HLGR), high-level streptomycin resistance (HLSR), ampicillin, and vancomycin resistance were observed in 25, 5, 10, and 5.15% of E. faecium, and 15, 6, 15, and 3.03% of E. faecalis isolates, respectively. The ant(6')-Ia and ant(3')-Ia genes that were responsible for streptomycin resistance were observed in HLSR isolates and aph(3')-IIIa and aac(6') Ie-aph(2″)-Ia genes accounting for gentamicin resistance were detected in HLGR isolates. vanA was the predominant gene detected in vancomycin-resistant isolates. The majority of isolates were positive for gelE, asa1, esp, cylA, and hyl virulence genes. We found that drug-resistant and virulent E. faecalis and E. faecium isolates were prevalent in hospital wastewater. Proper treatment strategies are required to prevent their dissemination into the environment.

A Genomic Snapshot of Antibiotic-ResistantEnterococcus faecalis within Public Hospital Environments in South Africa

Enterococci are among the most common opportunistic hospital pathogens. This study used whole-genome sequencing (WGS) and bioinformatics to determine the antibiotic resistome, mobile genetic elements, clone and phylogenetic relationship of Enterococcus faecalis isolated from hospital environments in South Africa. This study was carried out from September to November 2017. Isolates were recovered from 11 frequently touched sites by patients and healthcare workers in different wards at 4 levels of healthcare (A, B, C, and D) in Durban, South Africa. Out of the 245 identified E. faecalis isolates, 38 isolates underwent whole-genome sequencing (WGS) on the Illumina MiSeq platform, following microbial identification and antibiotic susceptibility tests. The tet(M) (31/38, 82%) and erm(C) (16/38, 42%) genes were the most common antibiotic-resistant genes found in isolates originating from different hospital environments which corroborated with their antibiotic resistance phenotypes. The isolates harboured mobile genetic elements consisting of plasmids (n = 11) and prophages (n = 14) that were mostly clone-specific. Of note, a large number of insertion sequence (IS) families were found on the IS3 (55%), IS5 (42%), IS1595 (40%), and Tn3 transposons the most predominant. Microbial typing using WGS data revealed 15 clones with 6 major sequence types (ST) belonging to ST16 (n = 7), ST40 (n = 6), ST21 (n = 5), ST126 (n = 3), ST23 (n = 3), and ST386 (n = 3). Phylogenomic analysis showed that the major clones were mostly conserved within specific hospital environments. However, further metadata insights revealed the complex intraclonal spread of these E. faecalis major clones between the sampling sites within each specific hospital setting. The results of these genomic analyses will offer insights into antibiotic-resistantE. faecalis in hospital environments relevant to the design of optimal infection prevention strategies in hospital settings.

Differences in Virulence Factors and Antimicrobial Susceptibility of Uropathogenic Enterococcus spp. Strains in a Rural Area of Uganda and a Spanish Secondary Hospital

Enterococcus faecalis and Enterococcus faecium have become two of the most important agents of nosocomial diseases due to their constantly growing resistance. Enterococcal infections are associated with biofilms, which are intrinsically sensitive to antimicrobials. The main goal of this study was to compare and relate their capacity to form biofilm and their antimicrobial sensitivity, as well as their virulence factors and their implicated genes, of strains isolated from patients with urinary tract infection (UTI) in a rural hospital in Uganda and a secondary hospital in Spain. A prospective study was conducted with 104 strains of E. faecalis and E. faecium isolated from patients with suspected UTI and who presented leukocyturia at the Saint Joseph Kitgum hospital (Uganda) and at the Hospital Universitario Principe de Asturias (Spain). All microorganisms were identified in Spain by MALDI-TOF mass spectrometry. Antimicrobial susceptibility studies were carried out using the Vitek^® 2 system (Biomériux, France). The biofilm formation capacity was studied by photospectrometry. Phenotypic and genotypic virulence factors were studied in all cases by PCR or expression techniques. In Uganda, we found a higher incidence of E. faecium (65.3%, n = 32), contrary to the situation found in Spain where most of the bacteria found belonged to E. faecalis (92.7%, n = 51). All E. faecalis strains were found to have very low levels of resistance to ampicillin, imipenem, and nitrofurantoin. However, E. faecium exhibited more than 25% resistance to these antibiotics. Although the esp gene has been shown in the results obtained to be an important initial agent in biofilm formation, we have also demonstrated in this study the intervention of other genes when esp is not present, such as the ace1 gene. No statistically significant relationships were found between the presence of agg and gelE genes and increased biofilm formation. The significant difference between the incidence of E. faecalis and E. faecium and biofilm formation, between samples from Spain and Uganda, shows us very different profiles between countries.

Prevalence of Class 1 Integron and In Vitro Effect of Antibiotic Combinations of Multidrug-Resistant Enterococcus Species Recovered from the Aquatic Environment in the Eastern Cape Province, South Africa

Enterococci are regarded as a better indication of faecal pollution in freshwater and marine waters. Their levels in seawater are positively connected with swimming-related gastrointestinal disorders. This study used an Enterococcus-specific polymerase chain reaction (PCR) to characterize the isolates. Classes 1 and 2 integrons were examined for environmental Enterococcus isolates using a standard biological procedure. All strains were assessed against a panel of 12 antibiotics from various classes using disc diffusion methods. The microdilution method was used to work out the minimum inhibitory concentration (MIC) according to the CLSI guiding principles. The combination therapy of the resistant drugs was evaluated using a checkerboard assay and a time-dependent test for assessing their bactericidal or bacteriostatic activity. The gene diversity of the tested organisms was analyzed with the aid of Enterobacterial Repetitive Intergenic Consensus (ERIC) PCR. In total, 57 Enterococcus spp. environmental samples were recovered, in which Enterococcus faecalis (33.33%) and Enterococcus faecium (59.65%) were the dominant species. Resistance to linezolid, ciprofloxacin, erythromycin, gentamicin, vancomycin, rifampicin, and tetracycline was prevalent. Fifty (50) strains tested positive for class 1 integron, more frequent in Enterococcus faecium and Enterococcus faecalis isolates, with no gene cassette array discovered. A combination of gentamicin (MIC 4 µg/mL) with vancomycin (MIC 256 µg/mL) antibiotics against Enterococcus faecalis showed antibacterial activity. In contrast, the combination of ciprofloxacin (1 µg/mL) with Ampicillin (16 µg/mL) antibiotics against Enterococcus faecalis showed a bacteriostatic effect. The ERIC-PCR analysis pointed out that most of the assessed isolates have close genetic similarities.

Occurrence of New Delhi Metallo-Beta-Lactamase 1 Producing Enterococcus Species in Oghara Water Nexus: An Emerging Environmental Implications of Resistance Dynamics

Various members of the enteric bacteria in recent times are evolving diverse survival mechanisms for antibiotic therapy resulting in failure of treatment in infection and disease cases. The Enterococcus species are potential strains implicated in gastrointestinal tract infection and are recently evolving in the resistance mechanism. The study evaluates the occurrence of New Delhi Metallo-beta-lactamase 1 (NDM-1) amongst Enterococcus species using the phenotypic and genomic characterization of environmental strains in the Oghara water nexus. Presumptive isolates of Enterococcus species were retrieved from various sampled water sources and confirmed using polymerase chain reaction (PCR). Antibiotic susceptibility testing was conducted on confirmed isolates using Kirby-Bauer disk diffusion methods. The result reveals 63 genus isolates confirmed Enterococcus species, of which 42 (67%) were Enterococcus faecium, 15 (23%) were Enterococcus faecalis, and 6 (10%) were other Enterococcus species. Fourteen among the E. faecalis isolates show resistance to Ertapenem-EDTA, while 17 (44.8%) of the E. faecium show resistance to Ertapenem-EDTA to presumptively reveal their NDM-1 phenotype. The PCR detection of the NDM-1 gene further confirmed 23 (36.5%) isolates as positive genotypes amongst the isolates that previously showed presumptive NDM-1 phenotype. It was also observed that 10 (15.9%) of Enterococcus faecium members harbored the NDM-1 genotype, whereas 8 (12.7%) members of the Enterococcus faecalis harbored the NDM-1 genotype. The observation of such resistance determinants necessitates a call for the adroit application of relevant therapeutics in the management of related infections and an environmental health caution to prevent the spread of such resistance potential enteric bacteria pathogens.

Resistance towards Critically Important Antimicrobials among Enterococcus faecalis and E. faecium in Poultry Farm Environments in Selangor, Malaysia

Multidrug resistant (MDR) enterococci pose significant public health challenges. However, the extent of resistance in the environment is less explored. This study aimed to determine the antibiotic resistance in a poultry farm environment. Eighty enterococcal isolates recovered from the soil and effluent water of 28 poultry farms in Selangor state were included in the study for further bacterial identification and antibiotic susceptibility testing using a VITEK 2 system. Data were analyzed using Statistical Package for Social Science (SPSS) version 27. The resistance rate and MDR of enterococcal isolates were reported. Out of 80 isolates recovered, 72 (90%) exhibited resistance to at least one antibiotic, with 50 isolates (62.5%) being found to be MDR. All linezolid-resistant enterococci (LRE) exhibit MDR, which constituted 40% of resistance among all the isolates recovered from poultry environment. Since linezolid is listed as critically important antibiotics for clinical use by the World Health Organization (WHO), the higher resistance towards it and other critically important antibiotic for human use is a serious concern. Hence, relevant agencies need to investigate the use of clinically important antimicrobials in poultry farms paying special attention towards linezolid or any other antibiotics that can facilitate the development of LRE.

Naturalized Escherichia coli in Wastewater and the Co-evolution of Bacterial Resistance to Water Treatment and Antibiotics

Antibiotic resistance represents one of the most pressing concerns facing public health today. While the current antibiotic resistance crisis has been driven primarily by the anthropogenic overuse of antibiotics in human and animal health, recent efforts have revealed several important environmental dimensions underlying this public health issue. Antibiotic resistant (AR) microbes, AR genes, and antibiotics have all been found widespread in natural environments, reflecting the ancient origins of this phenomenon. In addition, modern societal advancements in sanitation engineering (i.e., sewage treatment) have also contributed to the dissemination of resistance, and concerningly, may also be promoting the evolution of resistance to water treatment. This is reflected in the recent characterization of naturalized wastewater strains of Escherichia coli-strains that appear to be adapted to live in wastewater (and meat packing plants). These strains carry a plethora of stress-resistance genes against common treatment processes, such as chlorination, heat, UV light, and advanced oxidation, mechanisms which potentially facilitate their survival during sewage treatment. These strains also carry an abundance of common antibiotic resistance genes, and evidence suggests that resistance to some antibiotics is linked to resistance to treatment (e.g., tetracycline resistance and chlorine resistance). As such, these naturalized E. coli populations may be co-evolving resistance against both antibiotics and water treatment. Recently, extraintestinal pathogenic strains of E. coli (ExPEC) have also been shown to exhibit phenotypic resistance to water treatment, seemingly associated with the presence of various shared genetic elements with naturalized wastewater E. coli. Consequently, some pathogenic microbes may also be evolving resistance to the two most important public health interventions for controlling infectious disease in modern society-antibiotic therapy and water treatment.

An assessment of hospital wastewater and biomedical waste generation, existing legislations, risk assessment, treatment processes, and scenario during COVID-19

Hospitals release significant quantities of wastewater (HWW) and biomedical waste (BMW), which hosts a wide range of contaminants that can adversely affect the environment if left untreated. The COVID-19 outbreak has further increased hospital waste generation over the past two years. In this context, a thorough literature study was carried out to reveal the negative implications of untreated hospital waste and delineate the proper ways to handle them. Conventional treatment methods can remove only 50%-70% of the emerging contaminants (ECs) present in the HWW. Still, many countries have not implemented suitable treatment methods to treat the HWW in-situ. This review presents an overview of worldwide HWW generation, regulations, and guidelines on HWW management and highlights the various treatment techniques for efficiently removing ECs from HWW. When combined with advanced oxidation processes, biological or physical treatment processes could remove around 90% of ECs. Analgesics were found to be more easily removed than antibiotics, β-blockers, and X-ray contrast media. The different environmental implications of BMW have also been highlighted. Mishandling of BMW can spread infections, deadly diseases, and hazardous waste into the environment. Hence, the different steps associated with collection to final disposal of BMW have been delineated to minimize the associated health risks. The paper circumscribes the multiple aspects of efficient hospital waste management and may be instrumental during the COVID-19 pandemic when the waste generation from all hospitals worldwide has increased significantly.

Prevalence of CRISPR-Cas Systems and Their Possible Association with Antibiotic Resistance in Enterococcus faecalis and Enterococcus faecium Collected from Hospital Wastewater

Purpose

This study aimed to evaluate the presence of CRISPR-Cas system genes and their possible association with antibiotic resistance patterns of Enterococcus faecalis and Enterococcus faecium species isolated from hospital wastewater (HWW) samples of several hospitals.

Methods

HWW samples (200 mL) were collected from wastewater discharged from different hospitals from October 2020 to March 2021. The isolation and identification of enterococci species were performed by standard bacteriology tests and polymerase chain reaction (PCR). Antibiotic resistance was determined using the disc diffusion. The presence of various CRISPR-Cas systems was investigated by PCR. The association of the occurrence of CRISPR-Cas systems with antibiotic resistance was analyzed with appropriate statistical tests.

Results

In total, 85 different enterococci species were isolated and identified using phenotypic methods. The results of PCR confirmed the prevalence of 50 (58.8%) E. faecalis and 35 (41.2%) E. faecium, respectively. In total, 54 (63.5%) of 85 isolates showed the presence of CRISPR-Cas loci. The incidence of CRISPR-Cas was more common in E. faecalis. CRISPR1, CRISPR2, and CRISPR3 were present in 35 (41.2%), 47 (55.3%), and 30 (35.3%) enterococci isolates, respectively. The CRISPR-Cas positive isolates showed significant lower resistance rates against vancomycin, ampicillin, chloramphenicol, erythromycin, rifampin, teicoplanin, tetracycline, imipenem, tigecycline, and trimethoprim-sulfamethoxazole in comparison with CRISPR-Cas negative isolates. The results showed that the presence of CRISPR-Cas genes was lower in multidrug-resistant (MDR) isolates (53.1%, n = 26/49) compared to the non-MDR enterococci isolates (77.8%, n = 28/36) (P = 0.023).

Conclusion

This study revealed the higher prevalence of E. faecalis than E. faecium in HWWs. Also, the lack of CRISPR-Cas genes was associated with more antibiotic resistance rates and multidrug resistance in E. faecalis and E. faecium isolates with HWW origin.

Enteric bacterial pathogens and their antibiotic-resistant patterns from the environmental sources in different regions of Ethiopia: A laboratory-based cross-sectional study

Background and Aim

Antimicrobial resistance (AMR) resulting in the most significant public health and economic threat. Unfortunately, it is one of the missing topics on sustainable development goals (SDGs). Therefore, this laboratory-based study aimed at determining enteric bacterial pathogens and their antibiotic-resistant patterns from the environmental sources in different regions of Ethiopia.

Methods

A laboratory-based cross-sectional study was conducted by following the standard microbial culture and the Kirby-Bauer disc diffusion method for identification and AMR patterns of the enteric bacteria using a total of 180 environmental samples from January through June 2020. We employed descriptive statistics to examine the prevalence rate, comparability of results, and summary of AMR patterns of enteric bacteria and a 95% confidence Interval (CI) for considering the statistical significance and give conclusions by using Stata 14.1.

Results

The mean prevalence rates (SD) at 95% CI of AMR enteric bacterial pathogens were 53.13 (2.51)% (52.31, 53.95), 45 (1.85)% (44.40, 45.60), 32.5 (3.01)% (31.10, 33.00), and 31.12 (1.95)% (30.80, 31.45) in Wastewaters, leachate from solid waste dumping sites, waste receiving water bodies (Lake Tana at Bahir Dar and Boye Wetland at Jimma), and Soils sequentially. Specifically, Escherichia coli, Shigella, and Salmonella were 90 (3.10)% (89.00, 91.10), 67.5 (2.58)% (66.72, 68.41), and 45(1.58)% (44.48, 45.52), respectively, investigated in wastewater. In addition, solid waste dumping sites were contaminated with E. coli 80 (3.97)% (79.34, 80.66), Shigella 61 (2.87)% (59.06, 60.94), and Salmonella 42 (5.67)% (40.15, 43.85). This study implies that the waste discharges are the main source of contamination for AMR pathogens to the two aquatic water bodies.

Conclusion

The finding indicated that wastewater and solid waste dumping sites were important sources for AMR enteric pathogens. The finding might have indicated the tip of the iceberg about the environmental contamination with antimicrobial-resistant enteric pathogens.

Genomic Analysis of Multidrug-Resistant Enterococcus faecium Harboring vanA Gene from Wastewater Treatment Plants

The emergence of vancomycin-resistant Enterococcus faecium (Efm) harboring vanA gene and multidrug-resistant determinants is a relevant public health concern. It is an opportunistic pathogen responsible for nosocomial infections widely distributed in the environment, including wastewater treatment plants (WWTPs). Our study addresses a genomic investigation of vanA-carrying Efm from WWTPs in Brazil. Samples from five WWTPs supplied with sewage from different sources were evaluated. Here we present whole-genome sequencing of eight vanA-Efm isolates performed on Illumina MiSeq platform. All these isolates presented multidrug-resistant profile, and five strains were from treated wastewater. Multiple antimicrobial resistance genes (ARGs) were found, such as aph(3')-IIIa, ant(6')-Ia, erm(B), and msrC, some of them being allocated in plasmids. The virulence profile was predominantly constituted by efaAfm and acm genes and all isolates, except for one, were predicted as human pathogens. Multilocus sequence typing analysis revealed a new allele and five different STs, three previously described (ST32, ST168, and ST253) and two novel ones (ST1893 and ST1894). Six strains belonged to CC17, often associated with hospital outbreaks. As far as our knowledge, no genomic studies of vanA-Efm recovered from WWTPs revealed isolates belonging to CC17 in Brazil. Therefore, our findings point to the environmental spread of Efm carrying multiple ARGs.

Prevalence of antibiotic-resistant bacterial strains in wastewater streams: molecular characterization and relative abundance

Bacteria from wastewater discharged to the sewerage near three hospitals of Islamabad, Rawalpindi, and Faisalabad were examined for resistance to the most commonly prescribed antibiotics in Pakistan. From the selected sites, a total of 109 isolates from 40 different species were identified based on 16S rRNA gene sequence and phylogeny. The isolates were tested for their resistance to ciprofloxacin, levofloxacin, ofloxacin, amoxicillin, and ampicillin. The results indicated that the isolates were resistant with the highest percentage to ampicillin and the lowest percentage to ciprofloxacin. Among the resistant isolates, 91.7% were found resistant to ampicillin, 83.5% to amoxicillin, 67.0% to ofloxacin, whereas only 27.5% to ciprofloxacin and 21.1% to levofloxacin. Among three sampled locations, the most of resistance was observed in Escherichia and Acinetobacter species. More than 30% isolated microorganisms were found resistant to more than three antibiotics. These findings concluded the presence of predominant microbial population resistant to antibiotics in wastewater channels near hospitals and its surroundings, which requires further investigation regarding their existence and spread in other environmental media having potential community health implications.

Enterococcal contamination of hospital environments in KwaZulu-Natal, South Africa

AIMS

Enterococci are implicated in hospital-acquired infections and show high tenacity on inanimate objects in the hospital environment. This study investigated the prevalence of Enterococcus spp. in selected wards in public hospitals at four levels of healthcare from a district in KwaZulu-Natal, South Africa.

METHODS AND RESULTS

Swabs were collected from frequently touched areas in the paediatric wards and intensive care units (ICUs). Presumptive Enterococcus spp. were isolated and confirmed to genus and species levels, followed by Kirby-Bauer disk diffusion against 14 antibiotics. The results showed that enterococci were recovered from all 11 surfaces tested with the highest contamination rate observed on occupied beds and mops used to clean floors. A total number of 295 Enterococcus was identified. Polymerase chain reaction identified Enterococcus faecalis 83.1% (245/295) and Enterococcus faecium 12.9% (38/295), while whole genome sequencing identified Enterococcus gallinarum 2.0% (6/295) and Enterococcus casseliflavus 2.0% (6/295). Significant prevalence was observed in paediatric wards 64.1% (189/295) compared with the ICUs 35.9% (106/295), p < 0.05, in central, regional and district hospitals. Collectively, 82.0% (242/295) of enterococcal isolates were multidrug resistant, and 80 different antibiograms were observed. The most prominent antibiogram for E. faecium was CIP-RIF-NIT-TET-ERY and for E. faecalis CIP-TET-ERY.

CONCLUSION

E. faecalis was the most frequent enterococcal species isolated in all the hospitals investigated and correlates with studies conducted elsewhere. A substantially greater number of isolates were recovered from the paediatric wards compared with ICUs, and thus improved standards should be developed for infection control practices. It is suggested that the elevated use of antibiotics contributed to the increased nonsusceptible isolates observed from ICUs. This study highlighted the high recovery rate of enterococci in the hospital environment even in a nonoutbreak setting.

SIGNIFICANCE AND IMPACT OF THE STUDY

Enterocci had a high prevalence rate on the surfaces within the hospitals studied. This study gives an insight into the possible roles all healthcare staff may play in infection control intervention, including proper handling of hospital cleaning equipment and lack of knowledge about the potential for bacteria dissemination.

High throughput sequencing reveals the abundance and diversity of antibiotic-resistant bacteria in aquaculture wastewaters, Shandong, China

An innovative investigation was undertaken into the abundance and diversity of high antibiotic-resistant bacteria in aquaculture waters in Shandong Province, China, through cumulation incubation, PCR amplification of 16S rDNA, and high-throughput sequencing. The results showed that Vibrio, Bacillus, Vagococcus, Acinetobacter, Shewanella, Psychrobacter, Lactococcus, Enterococcus, Marinimonus and Myroids were abundant in the aquaculture waters, whereas other phylum including Actinobacteria, Deinococcus-Thermus, Omnitrophica and Nitrospirae had relatively lower abundance. Our studies revealed the presence of different bacteria in different locations in the aquaculture waters, most of which were resistant to multiple antibiotics. That is, the same microbial species from the same aquaculture wastewater can resist different antibiotics. Altogether, a considerable portion of the microbial community were found to be multi-drug resistant. It is essential that the spread of the antibiotic-resistant bacteria is controlled so that the distribution of antibiotic resistance genes to other environments is avoided.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s13205-021-02656-4.

Longitudinal Surveillance of Antibiotic Resistance in Escherichia coli and Enterococcus spp. from a Wastewater Treatment Plant and Its Associated Waters in KwaZulu-Natal, South Africa

We assessed the prevalence, distribution, and antibiotic resistance patterns of Escherichia coli and Enterococcus spp. isolated from raw and treated wastewater of a major wastewater treatment plant (WWTP) in KwaZulu-Natal, South Africa and the receiving river water upstream and downstream from the WWTP discharge point. Escherichia coli and enterococci were isolated and counted using the Colilert^®-18 Quanti-Tray^® 2000 and Enterolert^®-18 Quanti-Tray 2000 systems, respectively. A total of 580 quantitative PCR-confirmed E. coli and 579 enterococci were randomly chosen from positive samples and tested for in vitro antibiotic susceptibility using the disk diffusion assay against 20 and 16 antibiotics, respectively. The removal success of the bacterial species through the treatment procedure at the WWTP was expressed as log removal values (LRVs). Most E. coli were susceptible to meropenem (94.8%) and piperacillin-tazobactam (92.9%), with most Enterococcus susceptible to ampicillin (97.8%) and vancomycin (96.7%). In total, 376 (64.8%) E. coli and 468 (80.8%) Enterococcus isolates showed multidrug resistance (MDR). A total of 42.4% (246/580) E. coli and 65.1% (377/579) enterococci isolates had multiple antibiotic resistance indices >0.2. The LRV for E. coli ranged from 2.97 to 3.99, and for enterococci the range was observed from 1.83 to 3.98. A high proportion of MDR E. coli and enterococci were present at all sampled sites, indicating insufficient removal during wastewater treatment. There is a need to appraise the public health risks associated with bacterial contamination of environmental waters arising from such WWTPs to protect the health of users of the receiving water bodies.

The Prevalence of Virulent and Multidrug-Resistant Enterococci in River Water and in Treated and Untreated Municipal and Hospital Wastewater

The aim of this study is to describe the drug resistance and virulence of enterococci in river water sampled downstream (DRW) and upstream (URW) from the wastewater discharge point, to determine the pool of virulent and drug-resistant enterococci in untreated wastewater (UWW) and the extent to which these bacteria are eliminated from hospital wastewater (HWW) and municipal wastewater treated (TWW) by biological and mechanical methods in a wastewater treatment plant (WWTP). A total of 283 strains were identified with the use of culture-dependent methods and PCR, including seven different species including E. faecalis and E. faecium which were predominant in all analyzed samples. Majority of the strains were classified as multidrug resistant (MDR), mostly on streptomycin and trimethoprim. Strains isolated from wastewater and DRW harbored van genes conditioning phenotypic resistance to vancomycin, the highest percentage of vancomycin-resistant strains (57.0%), mostly strains harboring vanC1 genes (27.6%), was noted in TWW. More than 65.0% of the isolated strains had different virulence genes, the highest number of isolates were positive for cell wall adhesin efaA and sex pheromones cob, cpd, and ccf which participate in the induction of virulence. Many of the strains isolated from TWW were resistant to a higher number of drugs and were more virulent than those isolated from UWW and HWW. The enterococci isolated from DRW and wastewater were characterized by similar multidrug resistance and virulence profiles, and significant correlations were observed between these groups of isolates. These findings suggest that pathogenic enterococci are released with TWW and can spread in the river, pose a serious epidemiological threat and a risk to public health.

Characterization and Antibiotic Susceptibility Profiles of Pathogenic Escherichia Coli Isolated from Diarrhea Samples within the Buffalo City Metropolitan Municipality, Eastern Cape, South Africa

Objectives:

Developing countries like South Africa are still faced with numerous challenges such as poor environmental sanitation, lack of clean drinking water and inadequate hygiene which have contributed largely to diarrheal infections and deaths in children. This study was aimed at investigating the prevalence of pathotypes, antimicrobial resistance and drug resistance determinants among Escherichia coli (E. coli) isolates from diarrhea stool samples within Buffalo City Municipality, Eastern Cape, South Africa.

Methods:

Fresh diarrheal stool samples were collected from 140 patients attending public health centres within the Municipality and presumptive E. coli isolates were obtained from the stool samples using E. coli chromogenic agar while PCR amplification methods were used to confirm the presumptive isolates as well as delineate them into pathotypes based on the presence of certain virulence genes. In addition, antimicrobial susceptibility and screening of some of the antimicrobial resistant determinants were performed on all the confirmed isolates.

Results:

A total of 394 presumptive E. coli isolates from 140 diarrhea stool samples were subjected to polymerase chain reaction amplification, of which 265 were confirmed positive as E. coli. Pathotypes delineation of the positive E. coli isolates validated the presence of ETEC 106 (40%), EAEC 48 (18%), DAEC 37 (14%), and EPEC 31 (11%) while no EIEC pathotype was detected. All E. coli isolates exhibited maximum susceptibility to gentamicin (95%), amikacin (91%), nitrofurantoin (91%), meropenem (90%), chloramphenicol (91%) norfloxacin (84%) and imipenem (83%). However, the isolates showed multidrug resistance to penicillin G, ampicillin, trimethoprim, tetracycline, doxycycline, and erythromycin, with over 71% of the isolates resistant to the drugs. The prevalence and distribution of the five resistance determinants assessed were as follow; sulphonamides; sulII (12%), beta lactams; [ampC (22%); blaTEM, (25%)], and tetracyclines (tetA (35%).

Conclusion:

The results from this study suggest the probable involvement of E. coli pathotypes as an etiologic agent of diarrhea in the study area and revealed high levels of multidrug resistance among the isolates, which could be a major health burden.

Prevalence of vancomycin-resistant enterococcus in Africa in one health approach: a systematic review and meta-analysis

Vancomycin-resistant enterococci are a global challenge currently as reported by the World Health Organization. It is also important to recognize that combating antimicrobial resistance needs to recognize the interconnections between people, animals, plants and their shared environment in creating public health, the so-called One Health approach. Although the presence of VRE has been described in many regions of the world, there is a lack of comprehensive data indicating their prevalence of in Africa. Therefore, this study aimed to aggregate the result of studies describing VRE reported across multiple regions in Africa. A literature search was conducted on PubMed, Google scholar, and Hinari with the term “Vancomycin resistance enterococcus in Africa” on August 1–3, 2019. All available articles were downloaded to “Endnote version 7.1” then to Microsoft Word 2013. Articles determined to meet our criteria for the review was extracted to Microsoft Excel 2013. Those articles that reported the prevalence of vancomycin resistance Enterococcus obtained from all sample types and published from 2010 to 2019 in the English language were included for the review. A meta-analysis was conducted with OpenMetaAnalyst version R.3.1.0 software. The effect size was determined using a binary random effect model and statically significant considered when p < 0.05. Heterogeneity determined with the inconsistency index. A leave one out analysis used to perform the sensitivity analysis. There were 151 articles identified from the database searches; of this, 36 articles included after extensive review with two independent authors. Out of 4073 samples collected, 1488 isolates identified with an overall pooled prevalence of VRE 26.8% (95% CI; 10.7–43.0%) in Africa with a one-health perspective. The analysis showed that considerable heterogeneity among the studies (I² = 99.97%; p < 0.001). Subgroup analysis in-country, African region, laboratory method, year of publication, and sample source showed that a high prevalence was identified from South Africa (74.8%), South African regions (74.8%), PCR (959.2%), 2010–2015 years (30.3%) and environmental (52.2%), respectively. This meta-analysis indicates that there was a high-pooled prevalence of vancomycin-resistant enterococci in African. A lot should be done to prevent and control the transmission of vancomycin resistance enterococci to a human being from the environment in the continent.

Prevalence, antibiotic resistance and virulence of Enterococcus spp. from wastewater treatment plant effluent and receiving waters in South Africa

Poorly operating wastewater treatment plants (WWTPs) result in faecal pollution of receiving waters, posing a health risk to humans and animals. The aim of this study was to determine the antimicrobial resistance patterns and presence of virulent genes in Enterococcus spp. isolated from three WWTPs' final effluent and receiving waters in the North West Province, South Africa. Sixty-three Enterococcus spp. were identified and their antimicrobial susceptibility, as well as the presence of five virulence genes, determined. The antibiotic inhibition zone diameter data were subject to cluster analysis. Sixty-eight percent of the screened Enterococcus spp. were resistant to three or more antibiotics and harboured plasmids. Five virulence genes were detected and six multi-virulence profiles observed. Cluster analysis indicated groupings of isolates from all three effluent points downstream together, and between plants 1 and 2 together. The findings of this study have demonstrated that Enterococcus spp. harbouring virulence factors and plasmids that mediate multiple antibiotic resistance are present in effluent and receiving water systems that support various social needs. This is a cause for concern and it is recommended that Enterococcus be used as an additional faecal indicator when microbiological quality of water is assessed.

Effects of tourist flows on antibiotic resistance in wastewater of a Greek island

AIM

Antibiotic resistance in wastewaters reflects the clinical resistome. This study aimed at investigating whether changes in the population size and composition in the popular tourist destination of Zakynthos island are associated with differentiation in the antibiotic resistance of environmental micro-organisms isolated from wastewater.

METHODS AND RESULTS

The resistance profiles of four species (Escherichia coli, Staphylococcus sp., Pseudomonas sp. and Enterococcus sp.) were studied in 124 raw and treated municipal wastewaters from November 2015 to August 2016. Isolates were tested against their susceptibility to several antibiotics of different antimicrobial categories. Data concerning the alteration in the population size and composition, due to the tourist mobility, were collected and logistic regression models were used to examine the relationships between antimicrobial resistance and population changes. The decrease in resistance of E. coli to amoxicillin-clavulanate, of enterococci to norfloxacin and ampicillin, and of pseudomonads to almost all antibiotics tested was associated with population increase due to tourist flows. In contrast, the presence of tourists was linked to an increase in quinupristin-dalfopristin resistant enterococci. Resistance of staphylococci did not change during the tourist period.

CONCLUSION

Changes in population composition in touristic areas are reflected in antibiotic resistance of environmental bacteria in wastewater.

SIGNIFICANCE AND IMPACT OF THE STUDY

In touristic areas, where people carrying different resistomes are merged, medication should be adapted accordingly.

Comparative genomics of vancomycin-resistant Enterococcus spp. revealed common resistome determinants from hospital wastewater to aquatic environments

The rise of vancomycin-resistant Enterococcus spp. (VRE) has led to treatment challenges in hospital settings worldwide. Hospital wastewater (HW) might disseminate this threat to the aquatic environment. Thus, this study elucidates the VRE resistance quotient (RQ) of different environmental matrixes in wastewater and compares genomic determinants of VRE strains recovered from HW to water resources. Presumptive Enterococcus spp. and VRE were quantified and isolated using standard microbiological procedures. Fourteen VRE genomes were then sequenced using an Illumina HiSeq X™ Ten platform. Subsequently, VRE genomes were compared based on antibiotic resistance genes, plasmids, bacteriophages, insertion sequences, transposons, virulence and pathogenicity. Wastewater effluent showed the highest RQ among all sampled matrixes. The phylogeny of vancomycin-resistant E. faecalis (VREfs) and E. faecium (VREfm) revealed a tree structure based on their respective sequence type. A comparative genomic analysis of 14 genomes highlighted regions encoding phage protein, phage holin, phage integrase, integrase and transposase on both query genomes and the reference genome. Acquired resistance to vancomycin was conferred by vanA, vanN, vanL, vanG and the intrinsic resistance vanC operons. Plasmids were dominated by the presence of conserved areas of the replication initiating genes (rep). The Tn3-like and Tn917 transposons were present in all erythromycin-carrying erm(B) isolated VRE genomes. All VRE genomes expect one were putatively predicted as human pathogens with varying degrees of virulence. The presence of such resistant bacteria in African water resource is of great public health concern. It is, therefore, recommended that these bacteria be tracked and characterised from different environments to contribute to improved epidemiological containment action.

Molecular epidemiology and mechanisms of antibiotic resistance in Enterococcus spp., Staphylococcus spp., and Streptococcus spp. in Africa: a systematic review from a One Health perspective

A systematic review of antibiotic-resistant Gram-positive bacteria in Africa from a One Health perspective is lacking. Here, we report result from a search for English-language articles on the resistance mechanisms and clonality of Gram-positive bacteria in Africa between 2007 and 2019 reported in PubMed, Web of Science, ScienceDirect, and African Journals OnLine; 172 studies from 22 different African countries were identified. Resistance genes, such as mecA, erm(B), erm(C), tet(M), tet(K), tet(L), vanB, vanA, vanC, and tet(O), were found to be common. Staphylococcus spp., Enterococcus spp., and Streptococcus spp. were the main species reported by the studies, with clones such as Staphylococcus aureus ST5 (n = 218 isolates), ST8 (n = 127 isolates), ST80 (n = 133 isolates), and ST88 (n = 117 isolates), and mobile genetic elements such as IS16 (n = 28 isolates), IS256 (n = 96), Tn916 (n = 107 isolates), and SCCmec (n = 4437 isolates) identified. SCCmec IV (n = 747 isolates) was predominant, followed by SCCmec III (n = 305 isolates), SCCmec II (n = 163 isolates), SCCmec V (n = 135 isolates), and SCCmec I (n = 79 isolates). Resistance to penicillin (n = 5926 isolates), tetracycline (n = 5300 isolates), erythromycin (n = 5151 isolates), rifampicin (n = 3823 isolates), gentamycin (n = 3494 isolates), sulfamethoxazole/trimethoprim (n = 3089 isolates), and ciprofloxacin (n = 2746 isolates) was common in most reports from 22 countries. Clonal dissemination of resistance across countries and between humans, animals, and the environment was observed. Resistance rates ranged from 1.4% to 100% for 15 of the studies; 10 were One Health-related studies. Strict infection control measures, antimicrobial stewardship, and periodic One Health epidemiological surveillance studies are needed to monitor and contain the threat of increasing antibiotic resistance in Africa.

The Contribution of Wastewater to the Transmission of Antimicrobial Resistance in the Environment: Implications of Mass Gathering Settings

Antimicrobial resistance (AMR) is the major issue posing a serious global health threat. Low- and middle-income countries are likely to be the most affected, both in terms of impact on public health and economic burden. Recent studies highlighted the role of resistance networks on the transmission of AMR organisms, with this network being driven by complex interactions between clinical (e.g., human health, animal husbandry and veterinary medicine) and other components, including environmental factors (e.g., persistence of AMR in wastewater). Many studies have highlighted the role of wastewater as a significant environmental reservoir of AMR as it represents an ideal environment for AMR bacteria (ARB) and antimicrobial resistant genes (ARGs) to persist. Although the treatment process can help in removing or reducing the ARB load, it has limited impact on ARGs. ARGs are not degradable; therefore, they can be spread among microbial communities in the environment through horizontal gene transfer, which is the main resistance mechanism in most Gram-negative bacteria. Here we analysed the recent literature to highlight the contribution of wastewater to the emergence, persistence and transmission of AMR under different settings, particularly those associated with mass gathering events (e.g., Hajj and Kumbh Mela).

Hospital wastewater treatment scenario around the globe

Wastewaters generated from hospitals contain pharmaceuticals residues, pathogens, chemical reagents, radionuclide, and other harmful matter. The wastewater characteristics, quantity, and handling methods have not only variations among countries but also within a country. Some hazardous substances of hospital wastewaters (HWWs) may have a regulatory status and should be treated accordingly while others have characteristics similar to that of domestic sewage. At a global level, guidelines do exist for treatment of these HWWs. But literatures have shown that legislation has various loopholes in implementation. This chapter outlines the current status of management and handling of HWWs around the major industrial hubs of worlds in two categories of developed (the United States, United Kingdom, and Europe) and developing (India, China, Iran, and Bangladesh) countries. Various literatures and guidelines of these countries have been referred which mainly highlight different treatment scenarios and status of coverage of HWW management guidelines.

Microbiology of hospital wastewater

The study of hospital wastewater (HWW) microbiology is important to understand the pollution load, growth of particular pathogenic microbes, shift and drift in microbial community, development and spread of antibiotic resistance in microbes, and subsequent change in treatment efficiencies. This chapter investigates the potential microbes such as bacteria, viruses, fungi, and parasites present in HWW along with the diseases associated and methods of treatment used. Due to the indiscriminate release of antibiotics from hospitals, HWW serves as a hotspot for emergence of antibiotic-resistance genes (ARGs) and antibiotic-resistance bacteria. This chapter discusses the ARGs occurrence in HWW, their prevalence in the environment, the molecular tools used for identification, and different mechanisms of horizontal gene transfer. Thus better understanding of the microbiology of HWW could further help in development of advanced treatment technologies for effective removal of microbes and their bioproducts (toxins and infectious nucleic acid) from HWW and contaminated water.

Annual changes in the occurrence of antibiotic-resistant coliform bacteria and enterococci in municipal wastewater

Wastewater contains subinhibitory concentrations of different micropollutants such as antibiotics that create selective pressure on bacteria. This phenomenon is also caused by insufficient wastewater treatment technology leading to the development and spread of antibiotic-resistant bacteria and resistance genes into the environment. Therefore, this work focused on monitoring of antibiotic-resistant coliform bacteria and enterococci in influent and effluent wastewaters taken from the second biggest wastewater treatment plant (Petržalka) in the capital of Slovakia during 1 year. Antibiotic-resistant strains were isolated, identified, and characterized in terms of susceptibility and biofilm production. All of 27 antibiotic-resistant isolates were identified mainly as Morganella morganii, Citrobacter spp., and E. coli. Multidrug-resistance was detected in 58% of isolated strains. All tested isolates could form biofilm; two strains were very strong producers, and 74% formed biofilm by strong intensity. The flow rate of the influent wastewater had a more significant impact on the number of studied bacteria than the temperature. Graphical abstract.

Occurrence of enterococci harbouring clinically important antibiotic resistance genes in the aquatic environment in Gauteng, South Africa

The development of antibiotic resistance and dissemination of its determinants is an emerging public health problem as it compromises treatment options of infections that were, until recently, treatable. Investigation of outbreaks of vancomycin resistant enterococci (VRE) suggests that the environment serves as a significant reservoir for antibiotic resistance genes (ARGs). However, there is a paucity of data regarding the presence of ARGs in the water sources in South Africa. In this study, water samples collected from wastewater treatment plants (WWTPs), surface water and hospital sewage were screened for enterococci harbouring genes conferring resistance to four classes of antibiotics. Enterococci isolates harbouring ARGs were detected in raw influent and treated wastewater discharge from WWTPs and hospital sewage water. Plasmid and transposon encoded ermB (macrolide), tetM and tetL (tetracycline) as well as aph(3')-IIIa (aminoglycosides) genes were frequently detected among the isolates, especially in E. faecalis. The presence of enterococci harbouring ARGs in the treated wastewater suggest that ARGs are discharged into the environment where their proliferation could be perpetuated. Among the enterococci clonal complexes (CCs) recovered from wastewater were E. faecium CC17 (ST18), which is frequently associated with hospital outbreaks and a novel E. faecalis sequence type (ST), ST780.

Systematic review in South Africa reveals antibiotic resistance genes shared between clinical and environmental settings

A systematic review was conducted to determine the distribution and prevalence of antibiotic-resistant bacteria (ARB), antimicrobial-resistant genes (ARGs), and antimicrobial-resistant gene determinants (ARGDs) in clinical, environmental, and farm settings and to identify key knowledge gaps in a bid to contain their spread. Fifty-three articles were included. The prevalence of a wide range of antimicrobial-resistant bacteria and their genes was reviewed. Based on the studies reviewed in this systematic review, mutation was found to be the main genetic element investigated. All settings shared 39 ARGs and ARGDs. Despite the fact that ARGs found in clinical settings are present in the environment, in reviewed articles only 12 were found to be shared between environmental and clinical settings; the inclusion of farm settings with these two settings increased this figure to 32. Data extracted from this review revealed farm settings to be one of the main contributors of antibiotic resistance in healthcare settings. ARB, ARGs, and ARGDs were found to be ubiquitous in all settings examined.

Conceptual environmental impact assessment of a novel self-sustained sanitation system incorporating a quantitative microbial risk assessment approach

In many developing countries, including South Africa, water scarcity has resulted in poor sanitation practices. The majority of the sanitation infrastructures in those regions fail to meet basic hygienic standards. This along with the lack of proper sewage/wastewater infrastructure creates significant environmental and public health concerns. A self-sustained, waterless "Nano Membrane Toilet" (NMT) design was proposed as a result of the "Reinvent the Toilet Challenge" funded by the Bill and Melinda Gates Foundation. A "cradle-to-grave" life cycle assessment (LCA) approach was adopted to study the use of NMT in comparison with conventional pour flush toilet (PFT) and urine-diverting dry toilet (UDDT). All three scenarios were applied in the context of South Africa. In addition, a Quantitative Microbial Risk Assessment (QMRA) was used to reflect the impact of the pathogen risk on human health. LCA study showed that UDDT had the best environmental performance, followed by NMT and PFT systems for all impact categories investigated including human health, resource and ecosystem. This was mainly due to the environmental credits associated with the use of urine and compost as fertilizers. However, with the incorporation of the pathogen impact into the human health impact category, the NMT had a significant better performance than the PFT and UDDT systems, which exhibited an impact category value 4E + 04 and 4E + 03 times higher, respectively. Sensitivity analysis identified that the use of ash as fertilizer, electricity generation and the reduction of NOx emissions were the key areas that influenced significantly the environmental performance of the NMT system.

The unravelled Enterococcus faecalis zoonotic superbugs: Emerging multiple resistant and virulent lineages isolated from poultry environment

This study aimed to investigate the zoonotic potential by virtue of phylogenetic analysis, virulence and resistance gene profiles of Enterococcus faecalis originating from poultry environment. The ERIC, BOX and RAPD PCR analysis showed the clustering of E. faecalis strains (n = 74) into five groups (G1-G5) and fifteen sub-clusters (B1-B15), which share 50%-80% similarities with ATCC E. faecalis and clinical strains of human infection. E. faecalis strains harboured seven enterocins genes including ent1097 (85%), entB (84%), enterolysinA (51%), entSEK4 (51%), entL50 (31%), entA (25.7%) and ent1071 (14.9%). The highest prevalence of gelE-sprE (90%), lip-fl (90%) followed by cylL (62%), hyl (60%), katA (16%) and cylA (5.4%) was observed in poultry isolates. The fsr operon and gelE-sprE was co-associated in 66.2% strains. E. faecalis also harboured biofilm and endocarditis-associated genes, including efaAfs (97%), ebp-pilli (ebpABC and srtC 69.9%-80%), asa1 (71%), agg (55%), ace (54%) and esp-Tim (3%). Despite all found sensitive to vancomycin, 98.6% strains were multi-drug resistant to five to twelve tested antimicrobials. An increased-level of resistance (≥32 μg/ml) was observed to ampicillin (8.1%), meropenem (21.6%), chloramphenicol (73.4%), erythromycin (90.5%), tetracycline (100%) and high-level resistance to kanamycin (79.7%) and gentamicin (52.7%). The multi-drug resistant E. faecalis (MDRe.f) were carried pbp4 (90%), tetL (90%), tetM (70%), ermB (81%), cat (52.7%), acc6-aph2 (58.1%), aaph(3)-III (49.9%), gyrA (97%) and parC (98%) genes. Moreover, these MDRe.f were also harboured, hospital-associated marker IS16 (58%) and pheromone responsive genes, that is ccf (88%), cpd (74%), cob (62%) and eep (66%). Thus, regardless of the distinct phylogenetic background of E. faecalis of poultry origin, ATCC E. faecalis and clinical strains of human origin, we found major similarities in virulence, resistance gene profiles and mobile genetic elements (IS16 and pheromone responsive plasmids), supporting the zoonotic/reverse zoonotic risk associated with this organism.

Occurrence, molecular and antimicrobial resistance of Enterococcus spp. isolated from raw cow's milk trade by street trading in Meknes city, Morocco

Background

Enterococcus spp. belongs to a group of pathogens which are responsible for serious infections. This study aims at highlighting the raw milk microbiological contamination and at providing data for prevalence and antimicrobial resistance of Enterococcus spp. isolated from raw cow's milk marketed (without any pasteurization) by street traders.

Methods

During the period of May 2015 through April 2016, 150 cow's raw milk samples were collected from street traders in Meknes city. They were examined for the identification of Enterococcus spp. using biochemical tests and 16S rRNA gene sequencing. The antimicrobial susceptibility of the isolates was determined.

Results

The results showed that 11.3% (17/150) of samples were positive for the presence of Enterococcus spp., of which 64.7% were identified as Enterococcus faecalis, 17.6% as Enterococcus faecium, 11.8% as Enterococcus durans and 5.9% as Enterococcus hirae. The antimicrobial susceptibility showed that all Enterococcus spp. were resistant to ampicillin. The species E. faecalis, E. faecium, E. durans and E. hirae were resistant to streptomycin, with percentages of 52.9% (9/17), 11.8% (2/17), 11.8% (2/17), and 5.9% (1/17) respectively. All isolated strains of E. faecalis and E. faecium were resistant to tetracycline. The multiple antibiotic resistance index was elevated in the majority of Enterococcus spp., reaching values higher than 0.5, indicating a risk for public health.

Conclusion

This study shows that the raw milk consumed by the population is contaminated with strains of Enterococcus resistant to antibiotics used in breeding for prophylactic purposes. This requires raising the awareness of those involved in the production and marketing of milk, so as to take measures to apply good hygienic practices and rationalize the use of zootechnical antibiotics.

Phenotype and genotype of lactic acid bacteria (LAB) isolated from the tiger grouper Epinephelus fuscoguttatus alimentary tract

Lactic acid bacteria (LAB) have been isolated successfully from the tiger grouper Epinephelusfuscoguttatus intestine. However, their genus or species have not been identified. Therefore, the objective of the present study was to characterize the three isolated LAB (KSBU-12C, KSBU-5Da, and KSBU-9) based on their phenotype and genotype. The LAB phenotype was examined by observing morphological features including cell morphology, spore production and motility. The physiological tests were performed in 6.5% NaCl at the  temperatures of 10 ^oC and 45 ^oC, and the biochemical tests were evaluated based on the production of enzymes catalase, oxidase and arginine dehydrolase, following  the Standard Analytical Profile Index, API 50 CH kit.  The genotype was examined based on 16S rDNA gene sequence analysis , and the products were analyzed using the BLAST (Basic Local Alignment Search Tool) NCBI database. The three isolates (KSBU-5Da, KSBU-12C, and KSBU-9) were categorized into the genus Enterococcus. 16S rDNA sequence analysis indicated that the isolates had 99% similarity to E. hirae ATCC 9790, registered in GenBank with accession number NR_075022.1. It was concluded that the three LAB isolates taken from the tiger grouper Epinephelus fuscoguttatus are E. hirae.

Characterization and susceptibility of streptococci and enterococci isolated from Nile tilapia (Oreochromis niloticus) showing septicaemia in aquaculture and wild sites in Egypt

Background

The present investigation was an endeavor into the elucidation of the disease-causing pathogen of streptococcosis in Nile tilapia (Oreochromis niloticus) in Egypt affecting adult fish cultured and wild fish in the Nile river. Fish were obtained from commercial fishermen, collected as part of their routine fishing activities. The researchers observed the routine fishing process and selected fish for use in the study, at the point of purchase from the fisherman.

Results

Diseased fish showed exophthalmia with accumulation of purulent and haemorrhagic fluid around eyes, and ventral petechial haemorrhages. The Post mortem examination revealed, abdominal fat haemorrhage, pericarditis and enlargement of the liver, spleen and kidney. Gram-stained smears revealed the presence of Gram-positive cocci, β-hemolytic, oxidase and catalase negative. Analysis of the 16S rRNA gene confirmed that the 17 tilapia isolates studied were 6/17 Enterococcus faecalis, 2/17 Enterococcus gallinarum, 3/17 Streptococcus pluranimalium, 2/17 Aerococcus viridans, 1/17 isolate of each Streptococcus dysgalactiae, Streptococcus anginosus, Lactococcus garvieae and Granulicetella elegans/Leuconostoc mesenteroides cremoris. It should be noted that there was no mixed infection. Multiple resistance was observed and the most frequent antibiotic combination was penicillin, ampicillin, vancomycin, chloramphenicol, rifampicin, ofloxacin, clindamycin, erythromycin and tetracycline representing eight classes.

Conclusions

Consequently, we concluded that Streptococcus species are an emerging pathogen for Nile tilapia aquaculture in Egypt and to be considered as a new candidate in the warm water fish diseases in Egypt with special reference to L. garvieae, S. dysgalactiae in addition to L. mesenteroides cremoris which was not reported before from tilapia and taking into consideration their zoonotic implications for public health.

Antibiotic Resistance and Antibiotic Resistance Genes in Escherichia coli Isolates from Hospital Wastewater in Vietnam

The environmental spread of antibiotic-resistant bacteria has been recognised as a growing public health threat for which hospitals play a significant role. The aims of this study were to investigate the prevalence of antibiotic resistance and antibiotic resistance genes (ARGs) in Escherichia coli isolates from hospital wastewater in Vietnam. Wastewater samples before and after treatment were collected using continuous sampling every month over a year. Standard disk diffusion and E-test were used for antibiotic susceptibility testing. Extended-spectrum beta-lactamase (ESBL) production was tested using combined disk diffusion. ARGs were detected by polymerase chain reactions. Resistance to at least one antibiotic was detected in 83% of isolates; multidrug resistance was found in 32%. The highest resistance prevalence was found for co-trimoxazole (70%) and the lowest for imipenem (1%). Forty-three percent of isolates were ESBL-producing, with the blaTEM gene being more common than blaCTX-M. Co-harbouring of the blaCTX-M, blaTEM and qepA genes was found in 46% of isolates resistant to ciprofloxacin. The large presence of antibiotic-resistant E. coli isolates combined with ARGs in hospital wastewater, even post-treatment, poses a threat to public health. It highlights the need to develop effective processes for hospital wastewater treatment plants to eliminate antibiotic resistant bacteria and ARGs.

Antibiotic resistance, efflux pump genes and virulence determinants in Enterococcus spp. from surface water systems

The aim of this study was to report on antibiotic susceptibility patterns as well as highlight the presence of efflux pump genes and virulence genetic determinants in Enterococcus spp. isolated from South African surface water systems. One hundred and twenty-four Enterococcus isolates consisting of seven species were identified. Antimicrobial susceptibility testing revealed a high percentage of isolates was resistant to β-lactams and vancomycin. Many were also resistant to other antibiotic groups. These isolates were screened by PCR, for the presence of four efflux pump genes (mefA, tetK, tetL and msrC). Efflux genes mefA and tetK were not detected in any of the Enterococcus spp. However, tetL and msrC were detected in 17 % of the Enterococcus spp. The presence of virulence factors in the Enterococcus spp. harbouring efflux pump genes was determined. Virulence determinants were detected in 86 % of the Enterococcus spp. harbouring efflux pump genes. Four (asa1, cylA, gel and hyl) of the five virulence factors were detected. The findings of this study have demonstrated that Enterococcus from South African surface water systems are resistant to multiple antibiotics, some of which are frequently used for therapy. Furthermore, these isolates harbour efflux pump genes coding for resistance to antibiotics and virulence factors which enhance their pathogenic potential.

An Analysis of the Effects of Vancomycin and/or Vancomycin-Resistant Citrobacter freundii Exposure on the Microbial Community Structure in Soil

The occurrence of antibiotics and antibiotic resistance genes in the environment has become a subject of growing concern. The extensive use of vancomycin and other pharmaceuticals may alter the biodiversity of soil microbial communities and select antibiotic-resistant bacteria. Therefore, the purpose of the study was to evaluate the impact of vancomycin and/or vancomycin-resistant Citrobacter freundii on soil microbial communities using the denaturing gradient gel electrophoresis (DGGE) and the phospholipid fatty acid (PLFA) approaches. The experiment had a completely randomized block design with the following treatments: control soil (C), soil with vancomycin (1 mg/kg soil-VA1), soil with vancomycin (10 mg/kg soil-VA10), soil with C. freundii (Cit), soil with vancomycin (1 mg/kg soil) and C. freundii (VA1+Cit), and soil with vancomycin (10 mg/kg soil) and C. freundii (VA10+Cit). A bacterial strain resistant to vancomycin was isolated from raw sewage collected from the municipal sewage treatment plant. The obtained results indicated that the antibiotic and/or the bacterial strain exerted a selective pressure that resulted in qualitative and quantitative changes in the population of soil microorganisms. However, a multivariate analysis showed that the genetic and structural diversity of the soil microbial community was primarily affected by the incubation time and to a lesser extent by the antibiotic and introduced bacteria. DGGE analysis clearly showed that certain species within the bacterial community were sensitive to vancomycin as was evidenced by a decrease in the values of S (richness) and H (Shannon-Wiener) indices. Moreover, a PLFA method-based analysis revealed alterations in the structure of the soil microbial community as indicated by changes in the biomass of the PLFA biomarkers specific for Gram-positive and Gram-negative bacteria as well as fungi. The changes observed in the community of soil microorganisms may decrease the rate of microbial-mediated processes, which can lead to a disturbance in the ecological balance of the soil ecosystem.

Virulence determinants and production of extracellular enzymes in Enterococcus spp. from surface water sources

Virulence factors in Enterococcus may be indicative of potential pathogenicity. The aim of this study was to determine the relationship between the presence of clinically relevant virulence genes, in Enterococcus spp. from environmental water, and their in vitro expression. One hundred and twenty-four Enterococcus isolates (seven species), from five surface water systems in the North West Province, South Africa, were screened for the presence of asa1, cylA, esp, gelE and hyl using polymerase chain reaction. The expression of cylA, hyl and gelE was determined by phenotypic assessments. Sixty-five percent of the isolates were positive for one virulence gene and 13% for two or more. Most frequently detected genes were gelE (32%) and cylA (28%). Enterococcal surface protein was absent in all isolates screened. The presence of virulence genes was correlated with their extracellular enzyme production. The results show that a large percentage of these environmental Enterococcus spp. possess virulence factors that could be expressed in vitro. This is a cause for concern and could have implications for individuals using this water for recreational and cultural purposes. Further investigation is required into the sources of these potential pathogenic Enterococcus isolates and measures to minimize their presence in water sources.

Sulfonamide and tetracycline resistance genes in total- and culturable-bacterial assemblages in South African aquatic environments

Antibiotic resistant bacteria are ubiquitous in the natural environment. The introduction of effluent derived antibiotic resistance genes (ARGs) into aquatic environments is of concern in the spreading of genetic risk. This study showed the prevalence of sulfonamide and tetracycline resistance genes, sul1, sul2, sul3, and tet(M), in the total bacterial assemblage and colony forming bacterial assemblage in river and estuarine water and sewage treatment plants (STP) in South Africa. There was no correlation between antibiotic concentrations and ARGs, suggesting the targeted ARGs are spread in a wide area without connection to selection pressure. Among sul genes, sul1 and sul2 were major genes in the total (over 10(-2) copies/16S) and colony forming bacteria assemblages (∼10(-1) copies/16S). In urban waters, the sul3 gene was mostly not detectable in total and culturable assemblages, suggesting sul3 is not abundant. tet(M) was found in natural assemblages with 10(-3) copies/16S level in STP, but was not detected in colony forming bacteria, suggesting the non-culturable (yet-to-be cultured) bacterial community in urban surface waters and STP effluent possess the tet(M) gene. Sulfamethoxazole (SMX) resistant (SMX(r)) and oxytetracycline (OTC) resistant (OTC(r)) bacterial communities in urban waters possessed not only sul1 and sul2 but also sul3 and tet(M) genes. These genes are widely distributed in SMX(r) and OTC(r) bacteria. In conclusion, urban river and estuarine water and STP effluent in the Durban area were highly contaminated with ARGs, and the yet-to-be cultured bacterial community may act as a non-visible ARG reservoir in certain situations.