Antibiotic exposure in a low-income country: screening urine samples for presence of antibiotics and antibiotic resistance in coagulase negative staphylococcal contaminants

Presence of antibiotics in children's urine: a silent risk beyond drinking water

This study investigated the presence of 32 antibiotic residues in drinking water, their potential association with antibiotic concentrations in children's urine samples, and anthropometric indicators. Water samples were collected from the primary water sources supplying Ilo, Peru (Pacocha and Pampa), and urine samples were analysed from children aged 2 to 10 years using liquid chromatography coupled to tandem mass spectrometry with triple quadrupole. Five antibiotics were detected in drinking water, with three of these representing a health risk due to high concentrations and risk quotients (RQ): Doxycycline (2.30), Sulfamethoxazole (1.04), and Metronidazole (25.68). Furthermore, there was no correlation between the antibiotics found in drinking water and those detected in urine samples, as the types and quantities of antibiotics differed. In urine samples, 21 antibiotics were detected in children from Pacocha and 19 from Pampa. The antibiotics and anthropometric variables did not show any significant correlation. Principal component analysis revealed that antibiotic profiles were highly similar across both areas, suggesting a shared source of contamination independent of drinking water. It is concerning that 100% of the children have at least three antibiotics in their urine, which could affect their health now and later in life.

A short review of human exposure to antibiotics based on urinary biomonitoring

Antibiotics play a role in preventing and treating infectious diseases and also contribute to other health risks for humans. With the overuse of antibiotics, they are widely distributed in the environment. Long-term exposure to multiple antibiotics may occur in humans through medication and dietary intake. Therefore, it is critical to estimate daily intake and health risk of antibiotics based on urinary biomonitoring. This review compares the strengths and weaknesses of current analytical methods to determine antibiotics in urine samples, discusses the urinary concentration profiles and hazard quotients of individual antibiotics, and overviews correlations of antibiotic exposure with the risk of diseases. Liquid chromatography-tandem mass spectrometry is most applied to simultaneously determine multiple types of antibiotics at trace levels. Solid-phase extraction with a hydrophilic-lipophilic balance adsorbent is commonly used to extract antibiotics in urine samples. Fifteen major antibiotics with relatively higher detection frequencies and concentrations include sulfaclozine, trimethoprim, erythromycin, azithromycin, penicillin V, amoxicillin, oxytetracycline, chlortetracycline, tetracycline, doxycycline, ofloxacin, enrofloxacin, ciprofloxacin, norfloxacin, and florfenicol. Humans can be easily at microbiological effect-based risk induced by florfenicol, ciprofloxacin, azithromycin, and amoxicillin. Positive associations were observed between specific antibiotic exposure and obesity, allergic diseases, and mental disorders. Overall, the accessible, automated, and environmentally friendly methods are prospected for simultaneous determinations of antibiotics at trace level in urine. To estimate human exposure to antibiotics more accurately, knowledge gaps need to be filled up, including the transformation between parent and metabolic antibiotics, urinary excretion proportions of antibiotics at low-dose exposure and pharmacokinetic data of antibiotics in humans, and the repeated sampling over a long period in future research is needed. Longitudinal studies about antibiotic exposure and the risk of diseases in different developmental windows as well as in-depth research on the pathogenic mechanism of long-term, low-dose, and joint antibiotic exposure are warranted.

Decontamination of emerging pharmaceutical pollutants using carbon-dots as robust materials

Environmental pollution is a critical issue that requires proper measures to maintain environmental health in a sustainable and effective manner. The growing persistence of several active pharmaceutical residues, such as antibiotics like tetracycline, and anti-inflammatory drugs like diclofenac in water matrices is considered an issue of global concern. Numerous sewage/drain waste lines from the domestic and pharmaceutical sector contain an array of toxic compounds, so-called "emerging pollutants" and possess adverse effects on entire living ecosystem and damage its biodiversity. Therefore, effective solution and preventive measures are urgently required to sustainably mitigate and/or remediate pharmaceutically active emerging pollutants from environmental matrices. In this context, herein, the entry pathways of the pharmaceutical waste into the environment are presented, through the entire lifecycle of a pharmaceutical product. There is no detailed review available on carbon-dots (CDs) as robust materials with multifunctional features that support sustainable mitigation of emerging pollutants from water matrices. Thus, CDs-based photocatalysts are emerging as an efficient alternative for decontamination by pharmaceutical pollutants. The addition of CDs on photocatalytic systems has an important role in their performance, mainly because of their up-conversion property, transfer photoinduced electron capacities, and efficient separation of electrons and holes. In this review, we analyze the strategies followed by different researchers to optimize the photodegradation of various pharmaceutical pollutants. In this manner, the effect of different parameters such as pH, the dosage of photocatalyst, amount of carbon dots, and initial pollutant concentration, among others are discussed. Finally, current challenges are presented from a pollution prevention perspective and from CDs-based photocatalytic remediation perspective, with the aim to suggest possible research directions.

Reservoir of Antibiotic Residues and Resistant Coagulase Negative Staphylococci in a Healthy Population in the Greater Accra Region, Ghana

Antimicrobial resistance threatens infectious disease management outcomes, especially in developing countries. In this study, the occurrence of resistant coagulase-negative staphylococci (rCoNS) and antibiotic residues in urine samples of 401 healthy individuals from Korle-Gonno (KG) and Dodowa (DDW) in Ghana was investigated. MALDI-ToF/MS with gram-staining techniques detected and identified the CoNS. SPE-LC-MS/MS detected and quantified nine commonly used antibiotics in the samples. The results showed 63 CoNS isolates detected in 47 (12%) samples, with S. haemolyticus (78%) and S. epidermidis (8%) being predominant. Most of the isolates (95%) were resistant to at least one antibiotic, with the highest resistance observed against sulphamethoxazole (87%). Resistance profiles in samples from DDW and KG were largely comparable, but with some differences. For instance, DDW isolates were more resistant to gentamicin (p = 0.0244), trimethoprim (p = 0.0045), and cefoxitin (p = 0.0078), whereas KG isolates were more resistant to erythromycin (p = 0.0356). Although the volunteers had not knowingly consumed antibiotics two weeks before sampling, antibiotic residues, ranging between 1.44-17000 ng mL-1 were identified in 22% of urine samples. Samples with antibiotic residues were likely to also contain rCoNS (89%). The most frequent antibiotics detected were tetracycline (63%) and ciprofloxacin (54%). Healthy individuals could thus be reservoirs of antibiotic residues and rCoNS at the community level.

Prevalence of Pharmaceuticals in Surface Water Samples in Ghana

Pharmaceuticals, among the emerging contaminants, are pseudopersistent and recently of serious concern due to universal use, toxicity, and resistance development at low concentrations. This study was aimed at assessing the prevalence and risk of eight pharmaceuticals in surface water used for vegetable irrigation in Ghana’s Kumasi and Sunyani metropolises, which are influenced by hospitals, sewage treatment facilities, and market effluents. Samples were concentrated via solid-phase extraction (SPE) while liquid chromatography was used to identify and quantify the analytes. Ibuprofen, acetaminophen, and diclofenac were the detected analgesics in this study, with concentrations stretching from below detection limit (not detected) to 319.0 ng/L, while amoxicillin, trimethoprim, and cefuroxime were the detected antibiotics with a concentration range of no detection to 840.0 ng/L. Based on the available long-term data, an environmental risk assessment was conducted. Because of the presence of ibuprofen, the lowest trophic level and fish were shown to be at risk. The estimated risk quotient values for antibiotics resistance were above 1 for all the antibiotics investigated in surface water impacted by the wastewater of hospitals and pharmaceutical companies’ except surface water impacted by sewage treatment plants (STPs) and market wastewater. The existence of these pharmaceuticals in surface water does not only point to a general concern for the environment but also a potential health risk on humans and other lives as a result of their impact on drinking water and vegetable production in Ghana.

Validity of caregivers' reports on prior use of antibacterials in children under five years presenting to health facilities in Gulu, northern Uganda

INTRODUCTION

Given the frequent initiation of antibacterial treatment at home by caregivers of children under five years in low-income countries, there is a need to find out whether caregivers' reports of prior antibacterial intake by their children before being brought to the healthcare facility are accurate. The aim of this study was to describe and validate caregivers' reported use of antibacterials by their children prior to seeking care at the healthcare facility.

METHODS

A cross sectional study was conducted among children under five years seeking care at healthcare facilities in Gulu district, northern Uganda. Using a researcher administered questionnaire, data were obtained from caregivers regarding reported prior antibacterial intake in their children. These reports were validated by comparing them to common antibacterial agents detected in blood and urine samples from the children using liquid chromatography with tandem mass spectrometry (LC-MS/MS) methods.

RESULTS

A total of 355 study participants had a complete set of data on prior antibacterial use collected using both self-report and LC-MS/MS. Of the caregivers, 14.4% (51/355, CI: 10.9-18.5%) reported giving children antibacterials prior to visiting the healthcare facility. However, LC-MS/MS detected antibacterials in blood and urine samples in 63.7% (226/355, CI: 58.4-68.7%) of the children. The most common antibacterials detected from the laboratory analysis were cotrimoxazole (29%, 103/355), ciprofloxacin (13%, 46/355), and metronidazole (9.9%, 35/355). The sensitivity, specificity, positive predictive value (PPV), negative predictive value and agreement of self-reported antibacterial intake prior to healthcare facility visit were 17.3% (12.6-22.8), 90.7% (84.3-95.1), 76.5% (62.5-87.2), 38.5% (33.0-44.2) and 43.9% (k 0.06) respectively.

CONCLUSION

There is low validity of caregivers' reports on prior intake of antibacterials by these children. There is need for further research to understand the factors associated with under reporting of prior antibacterial use.

Virulence Factors in Coagulase-Negative Staphylococci

Coagulase-negative staphylococci (CoNS) have emerged as major pathogens in healthcare-associated facilities, being S. epidermidis, S. haemolyticus and, more recently, S. lugdunensis, the most clinically relevant species. Despite being less virulent than the well-studied pathogen S. aureus, the number of CoNS strains sequenced is constantly increasing and, with that, the number of virulence factors identified in those strains. In this regard, biofilm formation is considered the most important. Besides virulence factors, the presence of several antibiotic-resistance genes identified in CoNS is worrisome and makes treatment very challenging. In this review, we analyzed the different aspects involved in CoNS virulence and their impact on health and food.

Factors Influencing Atypical Clinical Presentations during the 2017 Madagascar Pneumonic Plague Outbreak: A Prospective Cohort Study

In late 2017, Madagascar experienced a large urban outbreak of pneumonic plague, the largest outbreak to date this century. During the outbreak, there were widespread reports of plague patients presenting with atypical symptoms, such as prolonged duration of illness and upper respiratory tract symptoms. Reported mortality among plague cases was also substantially lower than that reported in the literature (25% versus 50% in treated patients). A prospective multicenter observational study was carried out to investigate potential reasons for these atypical presentations. Few subjects among our cohort had confirmed or probable plague, suggesting that, in part, there was overdiagnosis of plague cases by clinicians. However, 35% subjects reported using an antibiotic with anti-plague activity before hospital admission, whereas 55% had antibiotics with anti-plague activity detected in their serum at admission. Although there may have been overdiagnosis of plague by clinicians during the outbreak, the high frequency of community antibiotic may partly explain the relatively few culture-positive sputum samples during the outbreak. Community antibiotic use may have also altered the clinical presentation of plague patients. These issues make accurate detection of patients and the development of clinical case definitions and triage algorithms in urban pneumonic plague outbreaks difficult.

Coagulase-negative staphylococci in outpatient routines: the implications of switching from CLSI to BrCAST/EUCAST guidelines

Coagulase-negative staphylococci (CoNS) are frequently isolated in clinical specimens and are important reservoirs of resistance genes. In 2019, the Brazilian government set the BrCAST/EUCAST (Brazilian Committee on Antimicrobial Susceptibility Testing) guidelines as the national standard, resulting in changes in the interpretation of CoNS susceptibility tests. From outpatients, disk-diffusion susceptibility of 65 CoNS cultures were evaluated and compared using classification criteria from both CLSI and BrCAST/EUCAST. The isolates were identified using matrix assisted laser desorption ionization-time of flight (MALDI-TOF), and the presence of the mecA gene was determined. The most prevalent species were Staphylococcus saprophyticus (32.3%), S. haemolyticus (18.5%), and S. epidermidis (9.2%). Almost perfect agreement was seen between the guidelines, except concerning oxacillin and gentamicin, and the prevalence of multidrug resistant isolates increased with the use of BrCAST/EUCAST. Of all, 15 (23.1%) isolates, mainly S. epidermidis and S. haemolyticus, were positive for the mecA gene, and only three were detected when using CLSI or BrCAST/EUCAST disk-diffusion screening. This, using either guideline, could reveal the difficulty of determining oxacillin resistance. Using warning zones or molecular methods might well be indicated for CoNS. In conclusion, adoption of the BrCAST/EUCAST guidelines will result in certain artificial changes in epidemiological susceptibility profiles, and clinicians and institutions should be aware of the possible implications.

Antibiotic resistance patterns in human, animal, food and environmental isolates in Ghana: a review

Many articles have been published on resistant microorganisms isolated from humans, animals, foods and the environment in Ghana. However, there are no reviews that summarize the information on the isolates and antibiotics tested so far in the country. This literature review was completed through “PubMed” and “Google Scholar” searches. We included publications from the period 1975-2015 with a laboratory-based methodology to determine antibiotic resistance of strains isolated in Ghana. In total, 60 articles were included in the analysis with 10% of the articles carrying out nationwide research on antibiotic resistance. The regions of Ghana with the highest published articles were Greater Accra (40%), Ashanti (21.7%) and Northern Region (10%). Most of the studies (86.7%) were related to isolates collected from human samples followed by environmental (5%), animal (3%) and food samples (2%). Ten different bacteria genera were observed in the studies. The most common was Escherichia coli, followed by Staphylococcus spp., Mycobacterium spp. and Streptococcus spp. The highest mean resistance rate was encountered in Escherichia coli (62.2%) followed by Klebsiella spp. (60.4%) and Pseudomonas spp. (52.1%). High resistance rates have been found in Ghana, however, the data are skewed and some regions of the country have been neglected. There is a need for higher quality research to establish and monitor resistance patterns in Upper West, Brong-Ahafo, Volta and Eastern Regions of Ghana.

A cross-sectional study on antibiotic prescription in a teaching hospital in Ghana

Introduction

Antibiotic misuse is the paramount factor for antibiotic resistance. Tamale Teaching Hospital (TTH), located in Ghana’s Northern Region, is the biggest tertiary hospital in the Northern half of the country and consequently one of the biggest prescribers of antibiotics. Understanding the use of antibiotics in the TTH and providing information that could be inferred to develop strategies for antibiotic prescription is of extreme importance in this era of multiple and pan-resistant strains of pathogenic microorganisms.

Methods

A cross-sectional study on the use of antibiotics at TTH in the Northern region of Ghana was performed. Data were collected by reviewing 10% of patients’ files from January to June 2015 and then assessed for its appropriateness against the criteria based on the British National Formulary (BNF) 2015 and BNF children 2013-2014. Results were expressed in frequencies and percentages.

Results

A total of 617 patients’ records were included in this study. Up to 385 cases of different antibiotic misuse were found, comprising of 335 errors in prescriptions and 50 non-completed treatments. The most common prescription error was made on treatment duration (29.6%). The potential interactions were 16.7%.

Conclusion

The study revealed a high burden of antibiotics misuse in TTH. This suggests a need for the development of an antibiotic stewardship programme for the hospital.

Antibiotic Resistance Policy and the Stewardship Role of the Nurse

Government policy, at all levels, should reflect current scientific evidence to curb the spread of multidrug-resistant organisms (MDROs) and to promote healthier lives for citizens and the global community. The World Health Organization estimates that approximately 63,000 Americans die annually of infections from MDROs. Annual spending in the United States used to combat MDRO infections surpassed $35 billion in 2015. This article is a review of U.S. policy regarding MDROs and focuses on several means with which nurses can implement antibiotic stewardship within their practices to stall the creation and global spread of antibiotic-resistant organisms. Nurses are vital to successfully implementing methods of antibiotic stewardship as they are at the center of multidisciplinary health care teams and have the greatest direct patient contact of all members within the team. Methods of antibiotic stewardship include limiting the use of antibiotics within animal husbandry industries, promotion of health care policy in line with antibiotic stewardship standards, and adopting more stringent clinical prescribing practices of antibiotics used in human therapies. Application of these improvements to U.S. federal, state, and local facility policies is in line with current scientific evidence and will provide a framework for cohesive partnerships with nations and institutions abroad that also struggle with the spread of MDROs in their own communities.

A cross-sectional study on the prevalence of antibiotic use prior to laboratory tests at two Ghanaian hospitals

There has been a significant rise in global antibiotic use in recent years. Development of resistance has been linked to easy accessibility, lack of regulation of sale, increased tendency to self-medicate and the lack of public knowledge. The increase in antibiotic misuse, including self-medication, has not been well documented in developing countries. Antibiotic use prior to visiting health facilities has been found to be prevalent in developing countries. It has been identified by some studies to increase the likelihood of missed diagnoses and influence the outcome of bacteriological tests. This study is aimed at determining the prevalence of prior antibiotic use through a cross-sectional survey of patients undergoing laboratory tests at two health facilities in Ghana. Face-to-face questionnaires were used to interview 261 individuals chosen by random sampling of patients visiting the bacteriology laboratory of the hospitals within a two-month period. The questionnaire investigated participant demographic characteristics, knowledge about antibiotics and the nature of antibiotic use. Antibiotic property detection bioassay was performed on patient’s urine sample using a disk diffusion method to accurately determine antibiotic use within 72 hours. Culture results were used as an index to evaluate the effect of prior antibiotic use on bacteriological tests. Out of a 261 participants enrolled, 19.9% (95% CI, 14.9–24.9) acknowledged using antibiotics prior to their visit to the laboratory during the study period. On the contrary, 31.4% (95% CI, 25.7–37.5) of participants’ urine samples were positive for antimicrobial activity. Participants within the age ranges of 20–30, 31–40 and 41–50 years had significantly lower odds of urine antimicrobial activity. Participants who had urine antimicrobial activity were more likely to have no growth on their culture plates than participants who had no urine antimicrobial activity [OR 2.39(1.37–4.18), p = 0.002]. The most commonly used antibiotics were the penicillins, fluoroquinolones and metronidazole. Although, majority of the participant (54.8%) had knowledge of antibiotics, most of them had inadequate information on their proper use. The commonest indications for antibiotic use were aches and pains (30.3%), diarrhoea (43.3%) and urinary tract infections (28.0%). Prior antibiotic use was found to increase the likelihood of obtaining a culture negative result and can affect the outcome of bacteriological tests.

Occurrence and risk assessment of antibiotics in water and lettuce in Ghana

Hospital wastewater and effluents from waste stabilization ponds in Kumasi, Ghana, are directly discharged as low quality water into nearby streams which are eventually used to irrigate vegetables. The presence of 12 commonly used antibiotics in Ghana (metronidazole, ciprofloxacin, erythromycin, trimethoprim, ampicillin, cefuroxime, sulfamethoxazole, amoxicillin, tetracycline, oxytetracycline, chlortetracycline and doxycycline) were investigated in water and lettuce samples collected in three different areas in Kumasi, Ghana. The water samples were from hospital wastewater, wastewater stabilization ponds, rivers and irrigation water, while the lettuce samples were from vegetable farms and market vendors. Antibiotics in water samples were extracted using SPE while antibiotics in lettuce samples were extracted using accelerated solvent extraction followed by SPE. All extracted antibiotics samples were analyzed by HPLC-MS/MS. All studied compounds were detected in concentrations significantly higher (p=0.01) in hospital wastewater than in the other water sources. The highest concentration found in the present study was 15μg/L for ciprofloxacin in hospital wastewater. Irrigation water samples analyzed had concentrations of antibiotics up to 0.2μg/L. Wastewater stabilization ponds are low technology but effective means of removing antibiotics with removal efficiency up to 95% recorded in this study. However, some chemicals are still found in levels indicating medium to high risk of antibiotics resistance development in the environment. The total concentrations of antibiotics detected in edible lettuce tissues from vegetable farms and vegetable sellers at the markets were in the range of 12.0-104 and 11.0-41.4ng/kg (fresh weight) respectively. The antibiotics found with high concentrations in all the samples were sulfamethoxazole, erythromycin, ciprofloxacin, cefuroxime and trimethoprim. Furthermore, our study confirms the presence of seven antibiotics in lettuce from irrigation farms and markets, suggesting an indirect exposure of humans to antibiotics through vegetable consumption and drinking water in Ghana. However, estimated daily intake for a standard 60kg woman was 0.3ng/day, indicating low risk for human health.

Antimicrobial resistance among clinically relevant bacterial isolates in Accra: a retrospective study

Objective

The aim of this study was to determine the antimicrobial resistance pattern of bacterial isolates from different specimens at various hospitals and private diagnostic service laboratories in Ghana.

Results

A retrospective data of culture and sensitivity test results from 2016 were extracted from the microbiology record book of six laboratories in Accra, Ghana. The data included type of clinical specimen, sex of patient, name of bacterial isolate and antibiotic resistance profile. A total of 16.6% (n = 10,237) resistant isolates were obtained, however, the proportions of resistant isolates varied significantly between laboratories. High resistance towards tetracycline, ampicillin, cotrimoxazole and cephalosporins, but low towards amoxiclav and aminoglycosides, was observed. This study identified E. coli and Staphylococcus species as the major resistant bacteria from clinical specimen in Accra and the highest prevalence of the isolates was found in urine specimens in all six laboratories (69.1%, n = 204; 52.6%, n = 36; 52.3%, n = 350; 37.9%, n = 298; 53%, n = 219; 62.1%, n = 594) and in female patients (81.4, 50 and 69.5%). Regular surveillance and local susceptibility pattern analysis is extremely important in selecting the most appropriate and effective antibiotic for the treatment of bacterial infections.

Electronic supplementary material

The online version of this article (10.1186/s13104-018-3377-7) contains supplementary material, which is available to authorized users.

Coagulase-Negative Staphylococci Isolated from Human Bloodstream Infections Showed Multidrug Resistance Profile

Coagulase-negative staphylococci (CNS) are important pathogens causing nosocomial infections worldwide with increasing resistance to antimicrobials. The aim of this study was to characterize resistance aspects of CNS isolated from patients with bloodstream infections acquired in hospitals in Belo Horizonte, MG, Brazil. Staphylococcus strains were characterized using repetitive sequence-based polymerase chain reaction (rep-PCR) fingerprinting with (GTG)₅ primer. Phenotypic resistance was analyzed using AST-P5085 card (bioMérieuxVitek^®). PCR was used to detect mecA, vanA, blaZ, ermA/B/C, aac-aphD, and SCC-mec. For statistical analyses, we used hierarchical cluster, chi-square test (χ²), and correspondence. Several clusters were formed within the same species using (GTG)₅ primer, and strains showed resistance to the following antimicrobials: benzylpenicillin (100%); oxacillin (93.1%); gentamicin (36.3%); ciprofloxacin (63.7%); moxifloxacin (32.7%); norfloxacin (81.0%); erythromycin (86.2%); clindamycin (75.8%); linezolid, teicoplanin and vancomycin (1.7%); tigecycline (0%); fusidic acid (10.35%); rifampicin (13.7%); and trimethoprim/sulfamethoxazole (46.5%). Regarding genotypic analyses, 40%, 0%, 78%, 42%, 100%, 24%, and 30% were positive for mecA, vanA, blaZ, ermA, ermB, ermC, and aac-aphD, respectively. Regarding staphylococcal cassette mec (SCCmec) type, 3.4% presented type I; 5.0% type II; 27.1% type III; 20.3% type IIIA; and 32.2% type IIIB. Six clusters were formed and frequency distributions of resistant strains to oxacillin, gentamicin, ciprofloxacin, moxifloxacin, norfloxacin, erythromycin, clindamycin, linezolid, teicoplanin, vancomycin, fusidic acid, rifampicin, and trimethoprim/sulfamethoxazole, and mecA, blaZ, ermC, aac-aphD, and SCCmec type differed (p < 0.001). In conclusion, the strains investigated in this study were multidrug resistant and carried multiple antibiotic resistance genes.

Prevalence and antibiotic resistance of coagulase-negative Staphylococci isolated from poultry farms in three regions of Ghana

The use of antibiotics in animal production has been associated with the development and spread of antibiotic-resistant organisms including commensals. Coagulase-negative Staphylococcus (CoNS) species, which were until recently considered non-pathogenic, have been associated with opportunistic infections and high resistance to several antibiotics. This study sought to determine the prevalence, identity, and phenotypic resistance of coagulase-negative Staphylococcus spp. isolated from some selected poultry farms and farm workers in the Ashanti, Brong Ahafo, and Greater Accra regions of Ghana. Poultry litter samples and oral swabs of poultry farm workers were collected, from which bacterial species were isolated, identified, and analyzed. Various selective media were used for the presumptive identification of the different species. Confirmation of bacterial identity was done using matrix-assisted laser desorption/ionization time of flight (MALDI-TOF) mass spectrometry. Antibiotic susceptibility testing of the isolates was performed using the Kirby-Bauer disk diffusion method. Zones of growth inhibition were interpreted based on the European Committee on Antimicrobial Susceptibility Testing (EUCAST) guidelines. Two hundred and fifty-six coagulase-negative Staphylococcus spp., comprising S. sciuri (42.97%), S. lentus (35.94%), S. gallinarum (6.64%), S. xylosus (4.30%), S. haemolyticus (3.91%), S. saprophyticus (1.95%), and S. cohnii (0.39%) were confirmed by MALDI-TOF. CoNS were isolated from samples from the Brong Ahafo (48.83%), Ashanti (33.59%), and Greater Accra (17.78%) regions. Isolates from poultry litter constituted 55.47%, and farm workers 44.53%. All the isolates were susceptible to amoxicillin/clavulanic acid and amikacin. The isolates exhibited high resistance toward tetracycline (57.03%), doxycycline (43.75%), and oxacillin (43.36%). Multi-drug resistance (MDR) was observed in 19.14% of the isolates. MDR was higher in isolates obtained from poultry farm workers (61.22%) than isolates from poultry litter (38.78%). The above findings call for stricter monitoring of antibiotic usage in both animal production and in humans.

Multiclass method for the quantification of 92 veterinary antimicrobial drugs in livestock excreta, wastewater, and surface water by liquid chromatography with tandem mass spectrometry

A simple multiresidue method was developed for detecting and quantifying 92 veterinary antimicrobial drugs from eight classes (β-lactams, quinolones, sulfonamides, tetracyclines, lincomycins, macrolides, chloramphenicols, and pleuromutilin) in livestock excreta and water by liquid chromatography with tandem mass spectrometry. The feces samples were extracted by ultrasound-assisted extraction with a mixture of acetonitrile/water (80:20, v/v) and edetate disodium, followed by a cleanup using solid-phase extraction with an amino cartridge. Water samples were purified with hydrophilic-lipophilic balance solid-phase extraction column. Urine samples were extracted with acetonitrile and edetate disodium. Detection of veterinary antimicrobial drugs was achieved by liquid chromatography with tandem mass spectrometry using both positive and negative electrospray ionization mode. The recovery values of veterinary antimicrobial drugs in feces, urine, and water samples were 75-99, 85-110, and 85-101% and associated relative standard deviations were less than 15, 10, and 8%, respectively. The limits of quantification in feces, urine, and water samples were 0.5-1, 0.5-1, and 0.01-0.05 μg/L, respectively. This method was applied to determine real samples obtained from local farms and provides reliable quantification and identification results of 92 veterinary antimicrobial drugs in livestock excreta and water.

Uptake of antibiotics from irrigation water by plants

The capacity of carrot (Daucus corota L.) and lettuce (Lactuca sativa L.), two plants that are usually eaten raw, to uptake tetracycline and amoxicillin (two commonly used antibiotics) from irrigated water was investigated in order to assess the indirect human exposure to antibiotics through consumption of uncooked vegetables. Antibiotics in potted plants that had been irrigated with known concentrations of the antibiotics were extracted using accelerated solvent extraction and analyzed on a liquid chromatograph-tandem mass spectrometer. The plants absorbed the antibiotics from water in all tested concentrations of 0.1-15 mg L(-1). Tetracycline was detected in all plant samples, at concentrations ranging from 4.4 to 28.3 ng/g in lettuce and 12.0-36.8 ng g(-1) fresh weight in carrots. Amoxicillin showed absorption with concentrations ranging from 13.7 ng g(-1) to 45.2 ng g(-1) for the plant samples. The mean concentration of amoxicillin (27.1 ng g(-1)) in all the samples was significantly higher (p = 0.04) than that of tetracycline (20.2 ng g(-1)) indicating higher uptake of amoxicillin than tetracycline. This suggests that the low antibiotic concentrations found in plants could be important for causing antibiotics resistance when these levels are consumed.

Network Analysis of Sequence-Function Relationships and Exploration of Sequence Space of TEM β-Lactamases

The Lactamase Engineering Database (www.LacED.uni-stuttgart.de) was developed to facilitate the classification and analysis of TEM β-lactamases. The current version contains 474 TEM variants. Two hundred fifty-nine variants form a large scale-free network of highly connected point mutants. The network was divided into three subnetworks which were enriched by single phenotypes: one network with predominantly 2be and two networks with 2br phenotypes. Fifteen positions were found to be highly variable, contributing to the majority of the observed variants. Since it is expected that a considerable fraction of the theoretical sequence space is functional, the currently sequenced 474 variants represent only the tip of the iceberg of functional TEM β-lactamase variants which form a huge natural reservoir of highly interconnected variants. Almost 50% of the variants are part of a quartet. Thus, two single mutations that result in functional enzymes can be combined into a functional protein. Most of these quartets consist of the same phenotype, or the mutations are additive with respect to the phenotype. By predicting quartets from triplets, 3,916 unknown variants were constructed. Eighty-seven variants complement multiple quartets and therefore have a high probability of being functional. The construction of a TEM β-lactamase network and subsequent analyses by clustering and quartet prediction are valuable tools to gain new insights into the viable sequence space of TEM β-lactamases and to predict their phenotype. The highly connected sequence space of TEM β-lactamases is ideally suited to network analysis and demonstrates the strengths of network analysis over tree reconstruction methods.

Metro system in Guangzhou as a hazardous reservoir of methicillin-resistant Staphylococci: findings from a point-prevalence molecular epidemiologic study

Staphylococci are common causes of healthcare-associated and community-associated infections. However, limited data are available on the prevalence, phenotypes and molecular characteristics of Staphylococci in metro system around the world. 320 surface samples were collected from the Guangzhou metro system to isolate and characterize Staphylococci strains. Of the samples, 75.6% (242/320) were contaminated with Staphylococci. The Staphylococci isolates, especially the methicillin resistant isolates, were resistance to most of the antibiotics, with 79.8% (193/242) classified as multidrug resistant (MDR) strains. 8 strains of methicillin-resistant Staphylococcus aureus (MRSA) carried a range of staphylococcal cassette chromosome mec (SCCmec) types [I (1), II (3), III (2) and NT (2)]. Staphylococcus aureus isolates were classified into several ST types and showed possible cross transmissions of strains from various sources. All MRSA strains were positive for the qac gene, and only one methicillin-susceptible Staphylococci aureus (MSSA) strain was positive for the Panton-Valentine leukocidin (PVL) genes. This study demonstrated that environmental surfaces in the Guangzhou metro system may be a hazardous reservoir for transmission of Staphylococci to passengers. The resistance to antibiotics and disinfectants observed among isolates was also noteworthy.

Beta-Lactamase Producing Escherichia coli Isolates in Imported and Locally Produced Chicken Meat from Ghana

The use of antibiotics in food animals is of public health concern, because resistant zoonotic pathogens can be transmitted to humans. Furthermore, global trade with food may rapidly spread multi-resistant pathogens between countries and even continents. The purpose of the study was to investigate whether imported chicken meat and meat from locally reared chicken are potential sources for human exposure to multi resistant Escherichia coli isolates. 188 samples from imported and locally produced chicken meat were sampled and analyzed. 153 bacteria isolates were successfully cultured and identified as E. coli using MALDI-ToF. Of these 109 isolates were from meat whereas the remaining 44 were isolated from the cloaca of locally reared live chickens. Antimicrobial susceptibility test was done on the identified E. coli isolates. Additionally, beta-lactamases production (ESBL and/or AmpC) were phenotypically confirmed on all isolates showing resistance to cefpodoxime. Beta-lactamase producing (BLP) E. coli meat isolates were further genotyped. Antimicrobial resistance to four antibiotic markers with highest resistance was detected more frequently in isolates from local chickens compared to imported chickens (tetracycline 88.9% vs. 57.5%, sulphonamide 75.0% vs. 46.6%, ampicillin 69.4% vs. 61.6% and trimethoprim 66.7% vs. 38.4%). Beta-lactamase production was found in 29 E. coli meat isolates, with 56.9% of them being multiple drug resistant (≥ 3). The predominant phylogroup identified was B1 followed by A and D, with similar distribution among the isolates from meat of locally reared chickens and imported chickens. Beta-lactamase producing genotype blaCTX-M-15 (50%; 10/20) was the most frequently drug resistant gene detected. More BLP E. coli isolates were found in imported chicken meat compared to locally reared chickens, demonstrating that these isolates may be spreading through food trade. In conclusion, both imported and locally produced chicken meats are potential sources for human exposure to BLP E. coli.