Multiple antibiotic resistance index, fitness and virulence potential in respiratory Pseudomonas aeruginosa from Jamaica

Exploring the presence, genomic traits, and pathogenic potential of extended-spectrum β-lactamase Escherichia coli in freshwater, wastewater, and hospital effluents

AIMS

The purpose of this work was to study extended-spectrum β-lactamase (ESBL)-producing Escherichia coli (ESBL-EC) in freshwaters, hospital effluents, and wastewaters during two sampling campaigns in 2021.

METHODS AND RESULTS

Water sampling was performed at 24 stations in the Ourthe watershed in Belgium. A total of 644 ESBL (n = 642) and AmpC (n = 2) E. coli strains were isolated. Disk-diffusion assays were performed following the EUCAST's recommendations. All strains were tested for the presence of blaCTX-M-1, blaCTX-M-2, and blaCTX-M-9 gene groups by PCR. Genes belonging to blaCTX-M-1 and blaCTX-M-9 groups were detected, respectively, in 73.6% and 14.9% of the strains. No blaCTX-M-2 group's gene was found. A subset of strains (n = 40) was selected for whole genome sequencing. Escherichia coli serotype O18: H7 ST 1463 was predominant (n = 14) in the sequenced strains and showed pathogenicity in the Galleria mellonella larvae model. β-lactamase genes identified were blaCTX-M (n = 21), with blaCTX-M-15 mostly represented (n = 15), as well as blaTEM (n = 11), blaOXA (n = 7), blaSHV (n = 9), and carbapenemase (CP) genes were observed in several strains-blaKPC-3 (n = 19), blaNDM-1 (n = 1), blaVIM-1 (n = 2), and blaOXA-244 (n = 2)-even from freshwaters.

CONCLUSIONS

ESBL-EC are widely distributed in the aquatic environment in Belgium and contain a variety of ESBL and CP genes.

The role of identified and characterized bacteriophage ZCEC13 in controlling pathogenic and multidrug-resistant Escherichia coli in wastewater: in vitro study

The spread and development of Multi-Drug Resistant (MDR) bacteria in wastewater became beyond control and a global public health concern. The conventional disinfectants used in wastewater treatment methods have been becoming increasingly ineffective against a range of pathogenic and MDR bacteria. Bacteriophages are considered a novel approach to microbial control. Therefore, this study aims to explore the possibility of using phages against pathogenic and MDR Escherichia coli strains isolated from wastewater treatment plants. The wastewater samples were collected from two different treatment plants for E. coli isolation. The antibiotic sensitivity profile and occurrence of virulence and resistant genes were tested in 28 E. coli isolates. Phage ZCEC13 was selected based on its promising activity and host range to undergo identification and characterization. ZCEC13 was evaluated by transmission electron microscopy, genomic sequencing, in vitro lytic activity and tested for its stability under different conditions such as pH, Ultraviolet light exposure, and temperature. The results reported that ZCEC13 belongs to the Caudoviricetes class, with a high antibacterial dynamic. Phage ZCEC13 displayed high stability at different pH values ranging from 2 to 12, good tolerance to temperatures from -4 to 65°C, and high stability at UV exposure for 120 min. Respectively, the findings showed stability of the phage under several conditions and high efficiency in killing MDR bacteria isolated from the treatment plants. Further studies are encouraged to analyse the efficacy of phages as a microbial control agent in wastewater treatment plants.

Unveiling the ecological landscape of bacterial β-lactam resistance in Delhi-national capital region, India: An emerging health concern

Inappropriate antibiotic use not only amplifies the threat of antimicrobial resistance (AMR), moreover exacerbates the spread of resistant bacterial strains and genes in the environment, underscoring the critical need for effective research and interventions. Our aim is to assess the prevalence and resistance characteristics of β-lactam resistant bacteria (BLRB) and β-lactamase resistant bacterial genes (BLRBGs) under various environmental conditions within Delhi NCR, India. Using a culture-dependent method, we isolated 130 BLRB from 75 different environmental samples, including lakes, ponds, the Yamuna River, agricultural soil, aquatic weeds, drains, dumping yards, STPs, and gaushalas. Tests for antibiotic susceptibility were conducted in addition to phenotypic and genotypic identification of BLs and integron genes. The water and sediment samples recorded an average bacterial abundance of 3.6 × 106 CFU/mL and an average ampicillin-resistant bacterial count of 2.2 × 106 CFU/mL, which can be considered a potent reservoir of BLRB and BLRBGs. The majority of the BLRB discovered are opportunistic pathogens from the Bacillus, Aeromonas, Pseudomonas, Enterobacter, Escherichia, and Klebsiella genera, with Multiple Antibiotic Resistance (MAR) index ≥0.2 against a wide variety of β-lactams and β-lactamase (BLs) inhibitor combinations. The antibiotic resistance pattern was similar in the case of bacteria isolated from STPs. Meanwhile, bacteria isolated from other sources were diverse in their antibiotic resistance profile. Interestingly, we discovered that 10 isolates of various origins produce both Extended Spectrum BLs and Metallo BLs, as well as found harboring blaTEM, blaCTX, blaOXA, blaSHV, int-1, and int-3 genes. Enterobacter cloacae (S50/A), a common nosocomial pathogen isolated from Yamuna River sediment samples at Nizamuddin point, possesses three BLRBGs (blaTEM, blaCTX, and blaOXA) and a MAR index of 1.0, which is a major cause for concern. Therefore, identifying the source, origin and dissemination of BLRB and BLRGs in the environment is of the utmost importance for designing effective mitigation approaches to reduce a load of antimicrobial resistance factors in the environmental settings.

Characterization of biofilm formation and multi-drug resistance among Pseudomonas aeruginosa isolated from hospital wastewater in Dhaka, Bangladesh

Hospital wastewater has been identified as a hotspot for the emergence and transmission of multidrug-resistant (MDR) pathogens that present a serious threat to public health. Therefore, we investigated the current status of antibiotic resistance as well as the phenotypic and genotypic basis of biofilm formation in Pseudomonas aeruginosa from hospital wastewater in Dhaka, Bangladesh. The disc diffusion method and the crystal violet assay were performed to characterize antimicrobial resistance and biofilm formation, respectively. Biofilm and integron-associated genes were amplified by the polymerase chain reaction. Isolates exhibited varying degrees of resistance to different antibiotics, in which >80% of isolates showed sensitivity to meropenem, amikacin, and gentamicin. The results indicated that 93.82% of isolates were MDR and 71 out of 76 MDR isolates showed biofilm formation activities. We observed the high prevalence of biofilm-related genes, in which algD+pelF+pslD+ (82.7%) was found to be the prevalent biofilm genotypic pattern. Sixteen isolates (19.75%) possessed class 1 integron (int1) genes. However, statistical analysis revealed no significant association between biofilm formation and multidrug resistance (χ2 = 0.35, P = 0.55). Taken together, hospital wastewater in Dhaka city may act as a reservoir for MDR and biofilm-forming P. aeruginosa, and therefore, the adequate treatment of wastewater is recommended to reduce the occurrence of outbreaks.

Identification of antibiotic-resistant pathogens and virulence genes in Escherichia coli isolates from food samples in the Dhaka University campus of Bangladesh

The presence of antibiotic-resistant pathogens in food is a serious public health concern nowadays. This study focuses on the isolation and characterization of potentially pathogenic Escherichia coli and antimicrobial-resistant pathogens in chicken curry and potato smash samples collected from the canteens and cafeteria of Dhaka University in Bangladesh. Isolates were identified by their cultural, morphological, and biochemical tests (motility indole urease test, Kliger's iron agar test, catalase test, oxidase test, methyl red and Voges-Proskauer tests). The antibiotic susceptibility test was done by the disk diffusion method. The range of total bacterial count in the potato smash and chicken curry samples was from 1.4 × 104 to 1.6 × 108 CFU/g and from 2.4 × 103 to 2.6 × 106 CFU/g, respectively. Escherichia coli, Salmonella, Vibrio, Klebsiella, Citrobacter, Enterobacter, Proteus, Clostridium, Staphylococcus, Streptococcus, Micrococcus, Bacillus, and Sarcina strains were isolated in both samples. Isolates were highly resistant to ampicillin (90.90%) followed by colistin (52.27%), azithromycin (27.27%), and tetracycline 25%. Proteus species had the highest rate of multiple antibiotic resistance (MAR; 62.5%), followed by Citrobacter species (50%). The isolated E. coli strains were further analyzed through PCR assay to detect virulent genes (EPEC: eaeA 229 bp, bfpA 450 bp, ETEC elt 322 bp, EHEC hylA 534 bp, and EIEC ial 320 bp). One E. coli isolate had the eaeA target gene under EPEC pathotypes. Escherichia coli, as a fecal indicator, may indicate fecal contamination or poor and unhygienic food handling. The findings recommend further investigations to identify potential mechanisms of contamination and preventive measures to improve the food safety level in the canteens and restaurants.

Molecular characterization of Helicobacter pylori isolated from Nile Tilapia (Oreochromis niloticus) and fish handlers

BACKGROUND

Helicobacter pylori is a worldwide pathogen that affects both animals and humans with a wide environmental distribution, causing serious health problems in humans. This research has timely addressed the topic of new sources of H. pylori infection, which is currently a global issue, especially in developing countries. For this purpose, 115 Tilapia fish, 50 freshwater samples, and 88 fish-handlers' stool samples were investigated for the presence of H. pylori in Qena Governorate, Egypt. The applied techniques were antigen screening tests, culturing, and molecular methods through ureC gene amplification, and 16 S rRNA characterization.

RESULTS

Helicobacter pylori was detected in 7.83%, 14%, 4.35%, and 12% of the investigated fish and water samples by culture and PCR methods, respectively. Out of the total studied participants, 40 tested positive for H. pylori when screened by stool antigen test, of which 35 (39.77%), and 31 (35.23%) were confirmed by conventional and molecular techniques, respectively. The Fisher's exact test has shown a statistically significant correlation between H. pylori infection, sex, and age as risk factors, while the association was insignificant concerning the residence. Males contracted the infection at a higher rate than females (48.08% and 16.67%, respectively). Also, H. pylori infection rate was the highest among fish-handlers aged 36-45 years old (46.67%), followed by the 26-35 years old age group (39.53%). With regard to the residence, a higher occurrence rate was recorded in the rural (36.07%) than the urban population (33.33%). Helicobacter pylori isolates harbored the highest antimicrobial resistance against ampicillin (100%), metronidazole (95.24%), while the least antimicrobial resistance was recorded against levofloxacin (21.43%), and clarithromycin (26.20%). The phylogenetic analysis revealed a high degree of homology between the isolates selected from Tilapia fish, freshwater, and fish-handlers.

CONCLUSIONS

Our data emphasized the role that fish and freshwater play in disseminating H. pylori infection as one of the diseases that has a significant public health issue.

Multidrug-Resistant Staphylococcus aureus Strains Thrive in Dairy and Beef Production, Processing, and Supply Lines in Five Geographical Areas in Ethiopia

Livestock, farms, abattoirs, and food supply systems can become the source of foodborne pathogens, including S. aureus, in the absence of monitoring, general hygienic practices, and control. Studies are scarce on reservoirs (hiding places) and routes of entry of S. aureus into the food supply chain in Ethiopia. To fill these gaps, we evaluated the role of cows (milk), meat, equipment, and food handlers on the abundance and AMR of S. aureus in five geographical areas in central Oromia, Ethiopia. We isolated S. aureus from 10 different ecologies per area in 5 areas and tested their sensitivity to 14 antimicrobials of 9 different classes. We ranked the 5 areas and 10 ecologies by computing their multiple AMR index (MARI) at a cut-off value of 0.2 to determine 'high-risk' ecologies for AMR. We recorded as MDR if an isolate had resistance to ≥3 antimicrobial classes. We used a circos diagram to analyze if isolates with identical AMR patterns were shared between different ecologies. S. aureus is prevalent in central Oromia (16.1-18.3%), higher in dairy farms than in abattoirs, and varied among 10 ecologies (p < 0.001) but not among 5 areas (p > 0.05). Of the 92 isolates, 94.6% were penicillin-resistant. Their AMR prevalence was above 40% for 9 of 14 antimicrobials. All isolates (100%) had AMR in at least one antimicrobial class (range = 1-9; median = 5), indicating MDR was prevalent. The prevalence of MDR S. aureus varied (p < 0.05) among areas and 10 ecologies; the highest was in slaughter lines. All isolates had a MARI of >0.2, indicating drug overuse, and S. aureus's AMR burden is high in central Oromia. Dairy farms had higher MARI values (0.44) than abattoirs (0.39). Of 10 ecologies, the highest and lowest MARI values were in the beef supply chain, i.e., slaughter line (0.67) and butcher's hand (0.25). Of the 68 different AMR patterns by 92 isolates against 14 antimicrobials, 53 patterns (77.9%) were unique to individual isolates, indicating they were phenotypically dissimilar. MDR S. aureus was widespread in central Oromia in dairy and meat supply chains, contaminating milk, meat, equipment, and workers in farm and abattoir settings. In the absence of strict regulations and interventions, MDR S. aureus can be disseminated from these epicenters to the public.

A South African Perspective on the Microbiological and Chemical Quality of Meat: Plausible Public Health Implications

Meat comprises proteins, fats, vitamins, and trace elements, essential nutrients for the growth and development of the body. The increased demand for meat necessitates the use of antibiotics in intensive farming to sustain and raise productivity. However, the high water activity, the neutral pH, and the high protein content of meat create a favourable milieu for the growth and the persistence of bacteria. Meat serves as a portal for the spread of foodborne diseases. This occurs because of contamination. This review presents information on animal farming in South Africa, the microbial and chemical contamination of meat, and the consequential effects on public health. In South Africa, the sales of meat can be operated both formally and informally. Meat becomes exposed to contamination with different categories of microbes, originating from varying sources during preparation, processing, packaging, storage, and serving to consumers. Apparently, meat harbours diverse pathogenic microorganisms and antibiotic residues alongside the occurrence of drug resistance in zoonotic pathogens, due to the improper use of antibiotics during farming. Different findings obtained across the country showed variations in prevalence of bacteria and multidrug-resistant bacteria studied, which could be explained by the differences in the manufacturer practices, handling processes from producers to consumers, and the success of the hygienic measures employed during production. Furthermore, variation in the socioeconomic and political factors and differences in bacterial strains, geographical area, time, climatic factors, etc. could be responsible for the discrepancy in the level of antibiotic resistance between the provinces. Bacteria identified in meat including Escherichia coli, Listeria monocytogenes, Staphylococcus aureus, Campylobacter spp., Salmonella spp., etc. are incriminated as pathogenic agents causing serious infections in human and their drug-resistant counterparts can cause prolonged infection plus long hospital stays, increased mortality and morbidity as well as huge socioeconomic burden and even death. Therefore, uncooked meat or improperly cooked meat consumed by the population serves as a risk to human health.

Salmonella infection among the pediatric population at a tertiary care children's hospital in central Nepal: a retrospective study

Background

Typhoid fever, an infective bacterial disease, is capable of causing fatal systemic infection in humans, and in an era of antimicrobial resistance, it has become of public health importance. This study aimed to investigate the laboratory diagnosis of Salmonella bloodstream infection, its serotype, antimicrobial resistance pattern, and seasonal variation at a tertiary care children's hospital.

Methods

We undertook a retrospective, cross-sectional study by reviewing hospital-based laboratory records of patients whose blood culture samples were submitted from the outpatient department to the laboratory of a tertiary care children's hospital in Kathmandu, Nepal, from January 2017 to January 2019.

Results

Among the total blood culture samples obtained (n = 39,771), bacterial isolates (n = 1,055, 2.65%) belonged either to the Genus Enterobacteriaceae or Genus Acinetobacter. Altogether (n = 91, 8.63%), isolates were positive for Salmonella spp., which were further identified as Salmonella enterica subsp. enterica ser. Typhi (n = 79, 7.49%), Salmonella enterica subsp. enterica ser. Paratyphi A (n = 11, 1.04%), and Salmonella enterica subsp. enterica ser. Paratyphi B (n = 1, 0.1%). The median age of patients was 6  years (IQR: 4-9), with male and female patients constituting (n = 53, 58.24%; OR, 1.0; 95% CI, 0.60-1.67) and (n = 38, 41.76%; OR, 0.98; 95% CI, 0.49-2.05) cases, respectively. The disease was observed throughout the year, with a high prevalence toward the spring season (March-May). An antibiogram showed resistance more toward nalidixic acid with S. Typhi, comprising half the isolates (n = 52, 65.82%; p = 0.11). Resistance toward β-lactams with β-lactamase inhibitors (amoxicillin/clavulanate; 1.27%) was seen in a single isolate of S. Typhi. The multidrug resistance pattern was not pronounced. The multiple antibiotic resistance (MAR) index was in the range between 0.14 and 0.22 in S. Typhi and 0.22 and 0.23 in S. Paratyphi.

Conclusion

Salmonella Typhi was the predominant ser. Infection was common among children between 1 and 5 years of age, showing male predominance and with the spring season contributing to a fairly higher number of cases. Antimicrobial susceptibility testing of S. Typhi showed more resistance toward nalidixic acid, with only a single isolate resistant to β-lactamase inhibitors (amoxicillin/clavulanate). Alarming multidrug resistance patterns were not observed. The MAR index in this study indicates the importance of the judicious use of antimicrobials and hospital infection prevention and control practices.

Potential of Natural Phenolic Compounds as Antimicrobial Agents against Multidrug-Resistant Staphylococcus aureus in Chicken Meat

Staphylococcus aureus is one of the most widespread foodborne bacteria that cause high morbidity, mortality, and economic loss, primarily if foodborne diseases are caused by pathogenic and multidrug-resistant (MDR) strains. This study aimed to determine the prevalence of S. aureus in chicken meat in Egyptian markets. Thus, this study might be the first to assess the efficiency of different natural phenolic compounds as novel antibacterial agents against MDR S. aureus pathogens isolated from raw chicken meat in the Egyptian market. The incidence and quantification of pathogenic S. aureus were detected in retail raw chicken meat parts (breast, thigh, fillet, and giblets). In total, 73 out of 80 (91.3%) of the chicken meat parts were contaminated, with S. aureus as the only species isolated. Of the 192 identified S. aureus isolates, 143 were coagulase-positive S. aureus and 117 isolates were MDR (81.8%, 117/143). Twenty-two antibiotic resistance profile patterns were detected. One strain was randomly selected from each pattern to further analyze virulence and resistance genes. Extracted DNA was assessed for the presence of antibiotic-resistance genes, i.e., vancomycin-resistance (vanA), aminoglycosides-resistance (aacA-aphD), apramycin-resistance (apmA), and methicillin-resistance (mecA), penicillin-resistance (blaZ), and virulence genes staphylococcal enterotoxins (sea and seb), Panton-Valentine leucocidin (pvl), clumping factor A (clfA), and toxic shock syndrome toxin (tst). Clustering analyses revealed that six S. aureus strains harbored the most virulence and resistance genes. The activity of hydroquinone was significantly higher than thymol, carvacrol, eugenol, and protocatechuic acid. Therefore, phenolic compounds, particularly hydroquinone, could potentially alternate with conventional antibiotics against the pathogenic MDR S. aureus inhabiting raw chicken meat. Hence, this study indicates that urgent interventions are necessary to improve hygiene for safer meat in Egyptian markets. Moreover, hydroquinone could be a natural phenolic compound for inhibiting foodborne pathogens.

Microbiota and its antibiotic resistance profile in avocado Guatemalan fruits (Persea nubigena var. guatemalensis) sold at retail markets of Ibarra city, northern Ecuador

Introduction

Avocados are typically sold in unsanitary conditions at the retail markets in Ecuador, which can raise the risk of microbial contamination. These microorganisms could exhibit multi-antibiotic resistance (MAR), being a serious threat concern to human health. In this study, we aimed to evaluate the microbiota and its antibiotic resistance profile in avocado Guatemalan fruits (Persea nubigena var. guatemalensis), at ripe stage: immature, firm light green (ready to eat in 4 days), peel (AFPE) and pulp (AFPU), and mature intense green (ready to eat) peel (AMPE) and pulp (AMPU), to gain baseline information on the prevalence of MAR bacteria.

Methods

Culture-independent (16S rRNA metagenomics) and culture-dependent approach (to detect specific indicator microorganisms) were used. Moreover, antibiotic susceptibility of selected target indicator bacteria was assessed providing information about the antibiotic resistance (AR) among the groups.

Results

Based on 16S rRNA gene metagenomic analysis, over 99.78% of reads were classified as bacteria in all samples. Shannon diversity index varies from 1.22 to 2.22, with the highest bacterial population assigned to AFPE samples (1327 species). The highest microbial counts of indicator Staphylococcus spp. (STAPHY), Enterobacter spp. (ENT), and Listeria spp. (LIST), were detected in AMPE samples. Thirty percent of the selected STAPHYs, and 20.91% of Enterobacter (ENT) clones were resistant to various classes of antibiotics. The MAR index varies between 0.25 to 0.88 and was clone-, and fruit ripe stage-dependent.

Conclusions

The results indicated that ready to eat avocados contained detectable levels of MAR bacteria, including methicillin resistant (MR)-STAPHY, which may act as a potential vector for the spread of antibiotic resistance. To achieve the increase of the production and marketing of Fuerte cultivar in Ecuador, it is vitally important to consider valuable strategies to protect the fruits at the early ripe stage in future. Thus, it is crucial to set up efficient control measures and develop coordinated strategies to guarantee the microbiological quality of the food.

Genetic and Phenotypic Characterization of Subclinical Mastitis-Causing Multidrug-Resistant Staphylococcus aureus

The core objective of this study was to genetically and phenotypically characterize subclinical mastitis-causing multidrug-resistant Staphylococcus aureus (MDRSA). In addition, risk factors associated with subclinical mastitis caused by MDRSA were investigated. Bacterial cultures were performed on 2120 mammary quarters, 40 swabs of milk utensils, 5 bulk tank milk samples, and 11 nostril and 11 hand swabs from milkers from five dairy farms. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) was conducted for S. aureus identification. Antimicrobial resistance was screened phenotypically using the disk diffusion test in all S. aureus isolates. A biofilm formation assay; detection of genes associated with beta-lactam resistance, efflux pump, and biofilm formation; and pulsed-field gel electrophoresis (PFGE) were performed in all MDRSA isolates. Multi-locus sequence typing (MLST) was carried out in cefoxitin-resistant MDRSA isolates. A total of 188 S. aureus isolates from milk as well as two from milking utensils and one from bulk tank milk were identified. Most of the isolates (92.7%; 177 of 191) showed beta-lactam resistance, and 7% (14 of 191) were MDRSA. Interestingly, 36% (5 of 14) of MDRSA isolates were cefoxitin-resistant, but none carried mecA or mecC genes. Based on PFGE results, it was observed that S. aureus strains were more likely to be unique to a specific herd. Two clonal complexes were identified, CC97 (ST126; commonly livestock-associated) and CC1 (ST7440; usually community-associated). To the best of our knowledge, this is the first report of ST7440 isolated from bovine mastitis in Brazil. The risk factor results underscored the importance of considering parity, stage of lactation, SCC, milk production, and herd size when studying the risk of subclinical mastitis and antimicrobial resistance in S. aureus. Thus, to implement effective strategies to prevent subclinical mastitis in dairy herds and to minimize MDRSA spread, it is important to understand MDRSA strains' distribution and their antimicrobial resistance profile.

Staphylococcus aureus Induced Wound Infections Which Antimicrobial Resistance, Methicillin- and Vancomycin-Resistant: Assessment of Emergence and Cross Sectional Study

Background

Wound infection is a prevalent concern in the medical field, being is a multi-step process involving several biological processes. Methicillin-resistant S. aureus (MRSA) and vancomycin-resistant S. aureus (VRSA) infections often occur in areas of damaged skin, such as abrasions and open wounds.

Methods

This research aims to light the incidence of MRSA and VRSA in wound swabs, the antimicrobial susceptibility configuration of isolated S. aureus patterns in pus/wound samples collected from Saudi Arabian tertiary hospital. The cross section study, β- lactamase detection, VRSA genotyping, MAR index, D-test and VRSA genotyping are methods, which used for completed this research.

Results

Patients of several ages and genders delivered specimens from two hospitals in the Al jouf area, in the northern province of Saudi Arabia. S. aureus was found in 188 (34.7%) of the 542 wounds. The traumatized wounds provided 71 isolates (38.8%), surgical wound provided 49 isolates (26.8%) and abscess were represented 16 by isolates (8.7%). In the study, 123 (65.4%) out of 188 were MRSA, 60 (31.9%) were MSSA, and five (2.7%) were VRSA. Linezolid and rifampin were found to be the most effective antimicrobials with 100% in vitro antibacterial activity against S. aureus isolates. The Multiple antimicrobials resistance (MAR) index revealed 73 isolates (38.9%) with a MAR index greater than 0.2, and 115 (61.1%) less than 0.2. The D-test showed that of MLSb phenotypes among S. aureus, 22 (11.7%) strains were D-test positive (MLSbi phenotype), 53 (28.2%) strains were constitutive MLSc phenotypes, and 17 (9%) strains were shown to have MSb phenotypes. All VRSA isolates (n=5) were found to be positive for vanA, and no vanB positive isolates were detected in the study.

Conclusion

Regular monitoring and an antimicrobials stewardship program should be in place to provide critical information that can be utilized for empirical therapy and future prevention strategies.

Antimicrobial resistant Escherichia coli prevalence in freshwaters in Belgium and human exposure risk assessment

The objective of this work was to evaluate the antimicrobial resistant (AR) E. coli prevalence in recreational waters in Belgium and to assess the exposure risk for bathers. Nine stations were sampled during the 2021 bathing season. A total of 912 E. coli strains were isolated and tested by the disk diffusion method in accordance with EUCAST recommendations, including Extended-Spectrum Beta-Lactamase (ESBL) production. AR E. coli were counted at each bathing sites, 24% of strains were resistant to at least one antibiotic and 6% were Multi-Drug Resistant (MDR). A Multiple Antibiotic Resistance (MAR) index was calculated to compare the bathing sites. The Lesse river had the highest MAR index as well as the highest E. coli absolute abundance and the largest number of ESBL-producing E. coli. Conversely, the 3 lakes showed lower E. coli contamination levels and AR rates. A human health risk assessment of exposure to AR E. coli, based on the calculation of measured prevalence, was performed considering four different dose-response model scenarios. The human health risk (Pd) ranged from 10^-9 to 0.183 (children). The exposure probabilities were low, except for scenario 3 (E. coli O157:H7), which is the most severe.

Antimicrobial resistance and virulence genes of invasive Salmonella enterica from children with bacteremia in north-central Nigeria

Objectives

Bacteremia due to invasive Salmonella enterica has been reported earlier in children in Nigeria. This study aimed to detect the virulence and antibiotic resistance genes of invasive Salmonella enterica from children with bacteremia in north-central Nigeria.

Method

From June 2015 to June 2018, 4163 blood cultures yielded 83 Salmonella isolates. This is a secondary cross-sectional analysis of the Salmonella isolates. The Salmonella enterica were isolated and identified using standard bacteriology protocol. Biochemical identifications of the Salmonella enterica were made by Phoenix MD 50 identification system. Further identification and confirmation were done with polyvalent antisera O and invA gene. Antimicrobial susceptibility testing was done following clinical and laboratory standard institute guidelines. Resistant genes and virulence genes were determined using a real-time polymerase chain reaction.

Result

Salmonella typhi 51 (61.4%) was the most prevalent serovar, followed by Salmonella species 13 (15.7%), choleraesuis 8 (9.6%), enteritidis 6 (7.2%), and typhimurium 5 (6.1%). Fifty-one (61.4%) of 83 Salmonella enterica were typhoidal, while 32 (38.6%) were not. Sixty-five (78.3%) of the 83 Salmonella enterica isolates were resistant to ampicillin and trimethoprim-sulfamethoxazole, followed by chloramphenicol 39 (46.7%), tetracycline 41 (41.4%), piperacillin 33 (33.9%), amoxicillin-clavulanate, and streptomycin 21 (25.3%), while cephalothin was 19 (22.9%). Thirty-nine (46.9%) of the 83 Salmonella enterica isolates were multi-drug resistant, and none were extensive drug resistant or pan-drug resistant. A bla_TEM 42 (50.6%), floR 32 (38.6%), qnrA 24 (28.9%), tetB 20 (20.1%), tetA 10 (10.0%), and tetG 5 (6.0%) were the antibiotic resistance genes detected. There were perfect agreement between phenotypic and genotypic detection of antimicrobial resistance in tetracycline, ciprofloxacin, and chloramphenicol, while beta-lactam showed κ = 0.60 agreement. All of the Salmonella enterica isolates had the virulence genes invA, sopB, mgtC, and sip4D, while 33 (39.8%), 45 (51.8%), and 2 (2.4%) had ssaQ, spvC, and ljsGI-1, respectively.

Conclusion

Our findings showed multi-drug resistant Salmonella enterica in children with bacteremia in northern Nigeria. In addition, significant virulence and antimicrobial resistance genes were found in invasive Salmonella enterica in northern Nigeria. Thus, our study emphasizes the need to monitor antimicrobial resistance in Salmonella enterica from invasive sources in Nigeria and supports antibiotic prudence.

Cross-Sectional Study for Detection and Risk Factor Analysis of ESBL-Producing Avian Pathogenic Escherichia coli Associated with Backyard Chickens in Pakistan

The increasing incidence of extended-spectrum β-lactamase (ESBL)-producing Escherichia (E.) coli in backyard chicken farming in Pakistan is of serious concern. This study aimed to assess the prevalence, antimicrobial resistance patterns and risk factors associated with ESBL avian pathogenic E. coli (APEC) isolated from backyard chickens in the Jhang district, Punjab, Pakistan. In total, 320 cloacal swabs were collected from four breeds of backyard chicken (Aseel, Golden, Misri and Necked Neck). ESBL E. coli were phenotypically identified using double disc synergy test (DDST) and corresponding genes were confirmed by multiplex polymerase chain reaction (mPCR). Out of the 320 samples, 164 (51.3%) were confirmed as E. coli, while 74 (45.1%) were characterized as ESBL E. coli. The frequency of isolation of ESBL E. coli was highest in Aseel chickens (35.1%). Of the 164 confirmed E. coli, 95.1%, 78.6%, 76.8%, 71.3%, 70.1%, 68.9%, 60.4% and 57.3% were resistant against tylosin, doxycycline, cefotaxime, enrofloxacin, colistin, trimethoprim/sulfamethoxazole, chloramphenicol and gentamicin, respectively. The ESBL gene types detected and their corresponding proportions were bla_CTX-M (54.1 %, 40/74), bla_TEM, (12.2%, 9/74) and co-existence (bla_CTX-M and bla_TEM) were shown in 33.8% (25/74). The bla_CTX-M gene sequence showed homology to bla_CTX-M-15 from clinical isolates. The mean multiple antibiotic resistance index (MARI) was found to be higher among ESBL E. coli (0.25) when compared to non-ESBL E. coli (0.17). Both free-range husbandry management system (p = 0.02, OR: 30.00, 95% CI = 1.47-611.79) and high antimicrobial usage in the last 6 months (p = 0.01, OR: 25.17, 95% CI = 1.81-348.71) were found significantly associated with isolation of ESBL-producing E. coli in the tested samples using binary logistic regression analysis. This study confirmed the potential of backyard chickens as a reservoir for ESBL E. coli in the Jhang district, Punjab, Pakistan.

Characterization and comprehensive genome analysis of novel bacteriophage, vB_Kpn_ZCKp20p, with lytic and anti-biofilm potential against clinical multidrug-resistant Klebsiella pneumoniae

Introduction

The rise of infections by antibiotic-resistant bacterial pathogens is alarming. Among these, Klebsiella pneumoniae is a leading cause of death by hospital-acquired infections, and its multidrug-resistant strains are flagged as a global threat to human health, which necessitates finding novel antibiotics or alternative therapies. One promising therapeutic alternative is the use of virulent bacteriophages, which specifically target bacteria and coevolve with them to overcome potential resistance. Here, we aimed to discover specific bacteriophages with therapeutic potential against multiresistant K. pneumoniae clinical isolates.

Methods and Results

Out of six bacteriophages that we isolated from urban and medical sewage, phage vB_Kpn_ZCKp20p had the broadest host range and was thus characterized in detail. Transmission electron microscopy suggests vB_Kpn_ZCKp20p to be a tailed phage of the siphoviral morphotype. In vitro evaluation indicated a high lytic efficiency (30 min latent period and burst size of ∼100 PFU/cell), and extended stability at temperatures up to 70°C and a wide range of (2-12) pH. Additionally, phage vB_Kpn_ZCKp20p possesses antibiofilm activity that was evaluated by the crystal violet assay and was not cytotoxic to human skin fibroblasts. The whole genome was sequenced and annotated, uncovering one tRNA gene and 33 genes encoding proteins with assigned functions out of 85 predicted genes. Furthermore, comparative genomics and phylogenetic analysis suggest that vB_Kpn_ZCKp20p most likely represents a new species, but belongs to the same genus as Klebsiella phages ZCKP8 and 6691. Comprehensive genomic and bioinformatics analyses substantiate the safety of the phage and its strictly lytic lifestyle.

Conclusion

Phage vB_Kpn_ZCKp20p is a novel phage with potential to be used against biofilm-forming K. pneumoniae and could be a promising source for antibacterial and antibiofilm products, which will be individually studied experimentally in future studies.

Prevalence and Risk Factors Associated with Multidrug Resistance and Extended-Spectrum β-lactamase Producing E. coli Isolated from Healthy and Diseased Cats

Household cats have been identified as potential antimicrobial resistance (AMR) reservoirs, and the extended-spectrum β-lactamases (ESBL) producing E. coli circulating among cats has been more frequently reported globally, but the factors linked to its colonization remain poorly understood. Thus, the objectives of this study were to determine E. coli shedding and the occurrence of multidrug resistant (MDR)- and ESBL-producing E. coli, as well as to determine risk factors associated with colonization of MDR and ESBL-producing E. coli isolated from both healthy and diseased cats in the Eastern Province of Saudi Arabia. In a cross-sectional study, 2000 swabs were collected from five anatomical regions (anus, skin, ear canal, nares, and conjunctival sac) of 209 healthy and 191 diseased cats that were admitted to a veterinary clinic in the Eastern Province of Saudi Arabia. In addition, each cat owner filled out a questionnaire about their cat's demographics, management, health status, and antimicrobial usage. E. coli was detected in 165 (41.3%) of all cats, including 59 (28.2%) healthy and 106 (55.5%) diseased cats. In total, 170 E. coli isolates were found in healthy (35.3%) and diseased (64.7%) cats. Susceptibility testing revealed that 123 (72.4%) of the E. coli isolates were resistant to at least one of the tested antimicrobials. Overall, 17.6% (30/170) of E. coli isolates were MDR, with 10 (5.9%) and 20 (11.8%) isolates found in healthy and diseased cats, respectively. However, only 12 (7.1%) E. coli isolates were resistant to cefotaxime and harbored the bla_CTX-M gene (ESBL-producer), with seven (4.1%) in healthy and five (2.9%) in diseased cats. Risk factor analysis showed that the odds of MDR and ESBL-producing E. coli were (20 and 17) and (six and eight) times higher when the family and cats were previously treated with antimicrobials, respectively. The presence of a child in the cat's family was also linked to an increased risk of MDR E. coli colonization (OR = 3.4). In conclusion, a high frequency of MDR and ESBL-producing E. coli was detected among healthy and diseased cats in Saudi Arabia, raising concerns about transmission to humans and supporting the need of a "One Health" approach to address the potential threats of cats as AMR reservoirs.

Prevalence of Multidrug-Resistant Bacteria (Enteropathogens) Recovered from a Blend of Pig Manure and Pinewood Saw Dust during Anaerobic Co-Digestion in a Steel Biodigester

South Africa adopts intensive livestock farming, embracing the employment of huge quantities of antibiotics to meet the increased demand for meat. Therefore, bacteria occurring in the animal products and manure might develop antibiotic resistance, a scenario which threatens public health. The study investigated the occurrence of Gram-negative bacteria from eighteen pooled samples withdrawn from a single-stage steel biodigester co-digesting pig manure (75%) and pine wood saw dust (25%). The viable counts for each bacterium were determined using the spread plate technique. The bacterial isolates were characterised based on cultural, morphological and biochemical characteristics, using the Analytical Profile Index 20 e test kit. In addition, isolates were characterised based on susceptibility to 14 conventional antibiotics via the disc diffusion method. The MAR index was calculated for each bacterial isolate. The bacterial counts ranged from 104 to 106 cfu/mL, indicating manure as a potential source of contamination. Overall, 159 bacterial isolates were recovered, which displayed diverse susceptibility patterns with marked sensitivity to amoxicillin (100% E. coli), streptomycin (96.15% for Yersinia spp.; 93.33% for Salmonella spp.) and 75% Campylobacter spp. to nitrofurantoin. Varying resistance rates were equally observed, but a common resistance was demonstrated to erythromycin (100% of Salmonella and Yersinia spp.), 90.63% of E. coli and 78.57% of Campylobacter spp. A total of 91.19% of the bacterial isolates had a MAR index > 0.2, represented by 94 MAR phenotypes. The findings revealed multidrug resistance in bacteria from the piggery source, suggesting they can contribute immensely to the spread of multidrug resistance; thus, it serves as a pointer to the need for the enforcement of regulatory antibiotic use in piggery farms. Therefore, to curb the level of multidrug resistance, the piggery farm should implement control measures in the study area.

Unravelling the Distinctive Virulence Traits and Clonal Relationship among the Pseudomonas aeruginosa Isolates from Diabetic Patients

Infections with P. aeruginosa are three times more common in people with diabetes than in non-diabetic individuals. Investigations disclosing the distinguishing traits of P. aeruginosa strains to cause respiratory and wound infection in diabetics is limited. Wound swab and sputum from infected diabetic patients were used for the isolation of P. aeruginosa. The confirmed isolates were evaluated for their virulence factor production, antibiotic susceptibility, and clonal relationship. The study confirmed the increased virulence of sputum isolates characterized by their multidrug resistant nature, strong biofilm formation at 72h [(p<0.05) =0.003)] and 96h [(p<0.05) =0.002)] and elaboration of proteolytic enzymes (40.0%). Albeit the fact that wound isolates were less virulent than the sputum isolates, there was an increased siderophore production (77.0%). Nearly 90.0% of the isolates including sputum and wound were resistant to colistin. Random Amplified Polymorphic DNA analysis showed no distinct lineages of wound and sputum isolates. The study disclosed the higher prevalence of virulent P. aeruginosa in causing infection in the diabetics. No distinct lineages of the wound and sputum isolates indicated their ability to adapt to different host environments. To the best of our knowledge, this is the first study to show the difference in virulence traits among the P. aeruginosa strains isolated from sputum and wound of diabetic patients. Our study distinctly reveals the significance of periodic examination of antibiotic resistance and virulence factors of P. aeruginosa in order to recognize the possible co-regulatory mechanism involved in their expression.

Antimicrobial Susceptibility and Molecular Characterization of Escherichia coli Recovered from Milk and Related Samples

There is a rising concern about illnesses resulting from milk consumption due to contamination by pathogenic microorganisms including Escherichia coli. This study examined the occurrence and antimicrobial susceptibility of E. coli isolated from cow milk and related samples. Furthermore, partial sequencing was done to ascertain the genetic relatedness and possible cross contamination among the samples. In all, 250 samples, that is, 50 each of raw milk, cow teat, milkers’ hands, milking utensils, and fecal matter of cows, were cultured for the identification of E. coli. E. coli was detected in 101/250 samples (40.4%). Milk and fecal samples recorded the highest percentages of 68.0% and 66.0%, respectively. Forty-two (42) E. coli strains examined for antimicrobial resistance showed an overall 25.5% resistance, 15.0% intermediate resistance, and 59.5% susceptibility. The isolates had a high level of resistance to teicoplanin (100.0%), but were susceptible to chloramphenicol (95.2%) and azithromycin (92.9%). The Multiple Antibiotic Resistance (MAR) index pattern ranged from 0.1 to 0.5, and 40.5% exhibited multiple drug resistance. The E. coli strains formed 11 haplotypes, and a phylogenic tree analysis showed relatedness among the isolates in other African countries. This observation is an indication of cross contamination among the milk and its related samples.

Prevalence, Antimicrobial Resistance, and Characterization of Staphylococcus aureus Isolated from Subclinical Bovine Mastitis in East Coast Malaysia

S. aureus is the pathogen that is commonly associated with subclinical mastitis, causing significant economic losses to dairy farms. This infection responds poorly to antimicrobial treatment, which could be due to the development of AMR, biofilm formation, and the intracellular invasion of S. aureus into bovine mammary cells leading to treatment failure. Thus, it is important to understand the challenge of this problem. Therefore, the present study aims to determine the prevalence, antimicrobial resistance, and characterization of S. aureus that was isolated from subclinical bovine mastitis in East Coast Malaysia. A total of 235 milk samples from dairy cows were collected from selected farms in Kelantan and Pahang. The samples were subjected to a somatic cell analysis to identify subclinical mastitis, followed by bacteria isolation and antimicrobial susceptibility testing. The isolated S. aureus were further analyzed for their ability to form biofilms and invade the bovine mammary epithelial cells (MAC-T cells) in in vitro infections modeling using a gentamicin protection assay. The overall total of 74/235 (31.4%; 95% CI = 0.31; 0.32) of the milk samples demonstrated >200,000 somatic cells/mL, suggesting the presence of subclinical mastitis in the animals. A total of 39/235 (16.5%; 95% CI = 0.16, 0.17) of the milk samples harbored S. aureus which demonstrated resistance towards the following antimicrobials: penicillin (18/39, 46%), ampicillin (17/39, 43.6%), oxacillin (12/39, 31%), tetracycline (10/39, 26%), and erythromycin (7/39, 18%). AMR was recorded for a total of (17/39, 43.6%) of S. aureus isolates. All isolates formed biofilms, with (8/30, 27%) strongly biofilm-forming, (18/30, 60%) moderately biofilm-forming, and the remaining (4/30, 13%) of isolates weakly biofilm-forming. Interestingly, the AMR isolates appear to produce weak and moderate biofilm. Moreover, (6/20, 30%) of the S. aureus isolates were invasive towards MAC-T cells, as indicated by their ability to evade gentamicin treatment. The study demonstrated the presence of AMR, invasiveness, and biofilm formation in S. aureus that was isolated from subclinical mastitis. This characteristic presents additional challenges to existing antimicrobial therapy.

Comparative Analysis of Human and Animal E. coli: Serotyping, Antimicrobial Resistance, and Virulence Gene Profiling

Widespread multidrug-resistant (MDR) and multi-virulent diarrheagenic E. coli create several crises among human and animal populations worldwide. For this reason, we looked forward to a breakthrough with this issue and tried to highlight these emerging threats. A total of 140 diarrheagenic E. coli isolates were recovered from animal and human sources. The O26 serotype, alongside the ampicillin/cefoxitin resistance phenotype, was predominant among both human and animal isolates. Of note, imipenem represented the most effective antibiotic against all the investigated isolates. Unfortunately, 90% and 57.9% of the tested isolates showed MDR and multi-virulent patterns, respectively. The animal isolates were more virulent and showed higher sensitivity to antimicrobial agents. Both animal and human isolates could not be arranged into related clusters. A strong negative correlation between the existence of virulence genes and antimicrobial resistance was clearly detected. A significant correlation between serotypes and antimicrobial resistance was not detected; meanwhile, a significant positive correlation between some serotypes and the presence of certain virulence genes was announced. Finally, our results confirmed the urgent need for restricted guidelines, in addition to new alternative therapies, due to the genetic diversity and wide spreading of MDR side by side with multi-virulent E. coli isolates.

Multidrug-resistant epi-endophytic bacterial community in Posidonia oceanica of Mahdia coast as biomonitoring factor for antibiotic contamination

Faced with the significant disturbances, mainly of anthropogenic origin, which affect the Mediterranean coastal ecosystem, Posidonia oceanica (L.) Delile has often been used to assess the state of health of this environment. The present study aims to determine the multidrug resistance patterns among isolated and identified epi-endophytic bacterial strains in P. oceanica seagrass collected from Mahdia coastal seawater (Tunisia). To investigate the bacterial community structure and diversity from coastal seawater samples from Mahdia, total DNA extraction and 16S rRNA gene amplification were performed and analyzed by denaturing gradient gel electrophoresis (DGGE). The DGGE profiles showed that some bands were specific to a given site, while other bands were found to be common to more than one sample. In the other hand, bacterial strains were isolated from 1 mL of leaves and epiphytes suspension of P. oceanica seagrass in marine agar. Forty-three isolates were obtained, seven of them were selected and identified on the basis of 16S rRNA gene sequence analysis. These isolates belonged to the genus Bacillus, exhibiting 98-100% of identity with known sequences. Susceptibility patterns of these strains were studied toward commonly used antibiotics in Tunisia. All identified isolates were resistant to Aztreonam (72.1%), Ceftazidime (60.5%), Amoxicillin (56%) and Rifampicin (51.2%). S5-L13 strain had presented the highest multidrug resistance with a MAR index of 0.67.

Ready-to-Eat Food as Sources of Extended-Spectrum β-Lactamase-Producing Salmonella and E. coli in Tamale, Ghana

The existence of antimicrobial-resistant pathogens in ready-to-eat food is an emerging public health concern. We evaluated the presence of extended-spectrum β-lactamase (ESBL)-producing Escherichia coli and Salmonella species in street food in Tamale, as well as their antibiotic resistance profiles. Samples (42 salad samples and 71 fufu samples) purchased from 113 food vendors in the metropolis were analyzed by selective enrichment and plated onto chromogenic media. The Kirby–Bauer disk diffusion method was used to determine the susceptibility to antibiotics and phenotypic ESBL production. Positive phenotypic analysis for ESBL production was shown in 55.4% (41/74) of E. coli and 44.6% (33/74) of Salmonella species. Antibiotic resistance characterization showed that ESBL strains from salad were completely sensitive to imipenem and chloramphenicol but mostly resistant to cefotaxime (70.0%), ceftriaxone (85.0%), and ceftazidime (70.0%). Nonetheless, 24.1% of ESBL strains from fufu were resistant to imipenem and least resistant to gentamicin (3.7%). In-vitro, E. coli were highly susceptible to ciprofloxacin, gentamicin, and erythromycin, as Salmonella species were more sensitive to imipenem and chloramphenicol; but in both species, resistance to β-lactam drugs was most prevalent. Multiple drug resistance was found in the entire ESBL strains of E. coli and Salmonella species (100%) with respective multiple antibiotic resistance (MAR) indices of 0.56 and 0.48 presented by E. coli and Salmonella species. Our study demonstrated the occurrence of ESBL-producing pathogens in vegetable salads and fufu. The existence of pathogenic bacteria in food is a public health threat and becomes more alarming when the pathogens are endowed with resistant features; thus, policies to combat antimicrobial resistance should be implemented and food safety prioritized.

Phenotypic detection, antimicrobial susceptibility and virulence profile of staphylococci in the pig production setting, Makurdi, Nigeria

Livestock, particularly pigs, have increasingly been recognized as important reservoirs for zoonotic transmission of pathogenic bacteria, including staphylococci. Livestock production systems in developing countries of sub-Saharan Africa, including Nigeria, are characterized by high misuse/abuse of antimicrobials and a close association between humans and these animals, which promotes the emergence and transmission of resistant and potentially virulent bacteria. In the present study, we investigated the occurrence and characteristics (species distribution, virulence and resistance profile) of staphylococci from smallholder backyard pig farms, slaughter slabs and pig handlers in Makurdi, Nigeria. A total of 330 nasal swabs originating from 300 pigs and 30 in-contact humans were collected and processed. One hundred and thirteen samples [34.2 %; 95 % confidence interval (CI): 29.1–39.6] comprising 103 (34.3 %; 95 % CI: 29.0–40.0) and 10 (33.3 %; 95 % CI: 17.3–52.8 %) samples from pigs and humans, respectively, were positive for staphylococci, yielding 120 isolates (pigs n=110, humans n=10). The 120 isolates were distributed into 15 species with Staphylococcus aureus (n=25) followed by Staphylococcus cohnii (n=19) and Staphylococcus sciuri (n=14) occurring more frequently. All isolates were resistant to β-lactam (100 %) antibiotics. Resistance to some critical antimicrobials, including linezolid (22 %), vancomycin (19.2 %), gentamicin (7.5%) and the fluoroquinolones ciprofloxacin (75.8 %) and enrofloxacin (66.7 %), was also observed. Majority (99.2 %) of the isolates displayed a multidrug resistance phenotype with the AMP-C-CIP-E-ENR-FOX-OX-P-S-SXT-TE phenotype being predominant. Overall, 70 % of the isolates expressed the methicillin resistance phenotype, out of which 20 % (n=17) were MRSA. Resistance to serum bactericidal activity and biofilm production were respectively observed in 45 (100 %) and 5 (11.3 %) of the coagulase-positive staphylococci. Our findings demonstrated the occurrence of a high diversity of staphylococci expressing multidrug resistance and potentially virulent phenotypes among healthy swine and pig handlers in small-scale backyard farms in North-Central Nigeria. These findings underscore the potential role of pig production settings in the emergence and dissemination of potentially virulent staphylococci and the importance of the development of antimicrobial resistance monitoring systems/implementation of control measures in developing countries. Proper hygienic practices and control of indiscriminate use and misuse of antibiotics are recommended.

Seasonal variations in the water quality and antibiotic resistance of microbial pollution indicators in the Mandovi and Zuari estuaries, Goa, India

The two adjacent estuaries of the rivers Mandovi and Zuari, along the Goa coast in the central west coast of India, are a large complex aquatic system hosting diverse natural habitats. The water quality in these habitats is affected by various anthropogenic activities as they are extensively used for transportation, fisheries and various recreational activities. In the present study, changes in the water quality and levels of microbial pollution during the pre-monsoon, monsoon and post-monsoon seasons were determined. The water quality index was estimated based on the parameters: temperature, salinity, pH, dissolved oxygen, biochemical oxygen demand and nutrients. The seasonal changes in the microbial pollution load were also assessed based on the abundance of pollution indicator organisms and their resistivity towards multiple antibiotics. Results show that the water quality index status was 'poor' in the pre-monsoon and post-monsoon seasons and it was 'good' only in the monsoon period. Levels of pollution indicator organisms determined show that the counts were the highest in the pre-monsoon season, which reduced in the monsoon and further declined during the post-monsoon season. However, the estimated multiple antibiotic resistance (MAR) index suggests that bacterial isolates in monsoonal water and sediment samples have maximum resistance towards antibiotics. This shows that, though the basic water quality improved during the monsoon, possibly due to substantial dilution, the increased terrestrial inputs brought harmful pathogens into these estuarine waters, which may be of potential health risk. Understanding the ecological status of the estuarine habitats is important for successful environmental management and sustainable development.

Evaluation of Multidrug-Resistant P. aeruginosa in Healthcare Facility Water Systems

According to the WHO, P. aeruginosa is one of the antibiotic-resistant bacteria that represent the biggest threat to public health. The aim of the study was to establish the prevalence of antibiotic-resistant P. aeruginosa in the water systems of various healthcare facilities over the course of nine years. A total of 4500 tap water system samples were taken from seventeen healthcare facilities. The culture method was used to detect P. aeruginosa, and the isolates were then tested for antibiotic resistance using the standardised disc diffusion method. Eleven antibiotics from five different classes were tested. P. aeruginosa was found to have contaminated 2.07% (no. 93) of the water samples. The majority of positive samples came from the dental units (30.11%) and the ward kitchens (23.66%). Considering the total isolates, 56.99% (no. 3) were resistant to at least one of the antibiotics tested. A total of 71.43% of P. aeruginosa isolated from water emerging from dental unit handpieces was antibiotic-resistant, with 45% of it resistant to ≥3 classes of antibiotics. Out of the total isolates, 19.35% showed resistance to carbapenems. It would be advisable to systematically screen tap water for opportunistic micro-organisms such as P. aeruginosa, as many countries already do, including this in the Water Safety Plan.

Predominance of genetically diverse ESBL Escherichia coli identified in resistance mapping of Vembanad Lake, the largest fresh-cum-brackishwater lake of India

Antimicrobial resistance (AMR) burden in Escherichia coli along the 90 km stretch of Vembanad Lake, Kerala, India, was assessed. Seventy-seven percent of water samples drawn from 35 different stations of the lake harbored E. coli. Antibiotic susceptibility test performed on 116 E. coli isolates revealed resistance to ≥ one antibiotic with 39 AMR profiles in 81%, multidrug resistance in 30%, and extended spectrum β-lactamase (ESBL) producers in 32%. Of all the 15 antibiotics tested, the probability of isolating cefotaxime-resistant E. coli was the highest (P ≤ 0.05) in the lake. Genetically diverse ESBL types, namely bla_TEM-116, bla_{CTX-M -152}, bla_{CTX-M -27}, bla_{CTX-M -55}, bla_CTX-M-205, and bla_SHV-27, were identified in the lake. This is probably the first report in India for the presence of bla_CTX-M-205 (bla_{CTX-M-group 2}) in the Vembanad Lake. ST11439 and single and double loci variants of ST443 and ST4533 were identified in multilocus sequence typing (MLST). Inc plasmids (B/O, F, W, I1, FIIA, HI1, P-1α, K/B, and N) identified in the lake evidences the resistance transmission potential of the E. coli isolated from the lake. Molecular typing (ERIC-PCR, MLST, and PBRT) delineated diverse E. coli, both between and within the sampling stations. Low multiple antibiotic resistance index (average MAR< 0.2) indicates a lower risk of the lake to the human population, but the occurrence of genetically diverse ESBL E. coli in the Vembanad Lake signals health hazards and necessitates pragmatic control measures.

Pseudomonas aeruginosa Biofilm Formation and Its Control

Microbes are hardly seen as planktonic species and are most commonly found as biofilm communities in cases of chronic infections. Biofilms are regarded as a biological condition, where a large group of microorganisms gets adhered to a biotic or abiotic surface. In this context, Pseudomonas aeruginosa, a Gram-negative nosocomial pathogen is the main causative organism responsible for life-threatening and persistent infections in individuals affected with cystic fibrosis and other lung ailments. The bacteria can form a strong biofilm structure when it adheres to a surface suitable for the development of a biofilm matrix. These bacterial biofilms pose higher natural resistance to conventional antibiotic therapy due to their multiple tolerance mechanisms. This prevailing condition has led to an increasing rate of treatment failures associated with P. aeruginosa biofilm infections. A better understanding of the effect of a diverse group of antibiotics on established biofilms would be necessary to avoid inappropriate treatment strategies. Hence, the search for other alternative strategies as effective biofilm treatment options has become a growing area of research. The current review aims to give an overview of the mechanisms governing biofilm formation and the different strategies employed so far in the control of biofilm infections caused by P. aeruginosa. Moreover, this review can also help researchers to search for new antibiofilm agents to tackle the effect of biofilm infections that are currently imprudent to conventional antibiotics.

Determination of frequency, multiple antibiotic resistance index and resistotype of Salmonella spp. in chicken meat collected from southeast of Iran

BACKGROUND

Zoonotic food-borne pathogens such as Salmonella spp., which can be hosted by some raw foods, play a crucial role in ranking the public health of a country OBJECTIVES: The present study was conducted to assess the frequency, antibiotic resistance pattern and index of multiple antibiotic resistance (MAR) of Salmonella spp. in chicken meat METHODS: A cross-sectional survey was conducted from October 2017 to March 2018. One-hundred and fifty chicken meat samples were collected from meat stores in Zahedan, southeast of Iran and screened for contamination with Salmonella spp. using the polymerase chain reaction assay targeting the inv-A gene. Antimicrobial susceptibility testing was performed against 11 commonly prescribed antimicrobial agents in the veterinary treatment to calculate the MAR index RESULTS: The contamination rate was 2.7% (4/150). The antimicrobial resistance rate was 100% (n = 4) against penicillin, tylosin, tetracycline, erythromycin and tiamulin, 50% (n = 2) against trimethoprim/sulfamethoxazole, difloxacin and lincomycin/spectinomycin and 25% (n = 1) against flumequine and florfenicol. All isolates were sensitive to fosfomycin. Interestingly, all isolates (n = 4) exhibited different MAR patterns. Furthermore, the MAR index ranged from 0.45 to 0.81 CONCLUSIONS: In addition to the MAR index, which indicated that the isolate originated from a source where antibiotics were used to a great degree and/or in large amounts, the results showed that the chicken meat hosted resistant strains of Salmonella spp. in the study area. Overall, the findings indicated an important public health problem. To reduce this alarming signal, the poultry industry should implement control measures in the study area.

Prevalence and Antimicrobial Resistance of Klebsiella Strains Isolated from a County Hospital in Romania

The study evaluated the evolution of the incidence of infections with Klebsiella in the County Clinical Emergency Hospital of Craiova (SCJUC), Romania. Also, we monitored antibiotic resistance over more than two years and detected changes in resistance to various antimicrobial agents. Our study included 2062 patients (823 women and 1239 men) hospitalised in SCJUC during the period 1st of September 2017 to 30 June 2019. In 458 patients (22.21%) from the 2062 total patients, the collected samples (1116) were positive and from those, we isolated 251 strains of Klebsiella spp. We conducted a longitudinal analysis of the prevalence of Klebsiella spp. over calendar months, which showed a prevalence in surgical wards that ranged between 5.25% and 19.49% in June 2018, while in medical wards the variation was much wider, between 5.15% and 17.36% in April 2018. Klebsiella spp. strains showed significant resistance to Amoxicillin/Clavulanate, Aztreonam and Cephalosporins such as Ceftriaxone, Ceftazidime and Cefepime. We examined the possible link with the consumption of antibiotics in the same month by performing a multiple linear regression analysis. The evolution of antibiotic resistance in Klebsiella was correlated with the variation of resistance in other bacteria, which suggests common resistance mechanisms in the hospital environment. By performing the regression for dependency between antibiotic resistance and antibiotic consumption, we observed some correlations between antibiotic consumption and the development of antibiotic resistance after 1, 2 and even 3 months (e.g., resistance to meropenem was influenced by the consumption in the hospital ward of imipenem 1 month and two months before, but only 1 month before by the consumption of meropenem). The clustering of strains showed filiation between multiresistant Klebsiella spp. strains isolated from specific patients from the ICU. The evolution of prevalence and antibiotic resistance in Klebsiella correlated with the resistance in other bacteria, which suggest common resistance mechanisms in the hospital environment, and also with the consumption of antibiotics.

Antibiotic Resistance Profile of Salmonella enterica Isolated from Exotic and Indigenous Leafy Green Vegetables in Accra, Ghana

ABSTRACT

Fresh produce-borne enteric bacterial pathogens that are resistant to antibiotics have posed serious challenges to food safety and public health worldwide. This study was conducted to evaluate the antibiotic resistance profiles of Salmonella enterica isolates (n = 33) recovered from exotic and indigenous leafy green vegetable samples (n = 328) collected from 50 vegetable farms in 12 farming areas and 37 vegetable sellers in four market centers in Accra, Ghana, from March 2016 to March 2017 and to determine the distribution of integrons among antibiotic-resistant isolates. The susceptibility of the Salmonella isolates to 12 antibiotics was assayed with the standard disk diffusion assay. The MICs of the five most resisted antibiotics were determined with a twofold macrodilution method. A PCR assay was used to detect the presence of integrons in Salmonella isolates, and PCR products with the amplified integron gene cassette were purified and sequenced with the Sanger sequencing technology. The Salmonella isolates used in the study were resistant to at least one tested antibiotic, and 30.3% (10 of 33) of the isolates were multidrug resistant. Most isolates (81.8%) were resistant to sulfisoxazole. The MICs of tetracycline, cefoxitin, streptomycin, ampicillin, and sulfisoxazole were 16, 32, 64, 64, and >1,024 μg/mL, respectively. Five patterns of multidrug resistance were observed among the Salmonella isolates, and the most common patterns were AAuFox (30.3%) and AAuFoxSSu (18.1%). One (3.0%) of the 33 Salmonella isolates tested positive for the class 1 integron, with a gene cassette of about 800 bp. Nucleotide sequencing revealed that this class 1 integron carried a single gene, dfrA7. Further studies are needed to determine whether the consumption of contaminated leafy green vegetables is a route for acquiring antibiotic-resistant Salmonella in Accra, Ghana.

HIGHLIGHTS

Characterization of Multidrug-Resistant Biofilm-Producing Escherichia coli and Klebsiella pneumoniae in Healthy Cattle and Cattle with Diarrhea

This study describes comparative occurrence and characterization of multidrug-resistant (MDR) Escherichia coli and Klebsiella pneumoniae (KP) in healthy cattle (HC) and cattle with diarrhea (DC) in India. During 2018-2020, 72 MDR isolates, including 35 E. coli (DC: 27; HC 8) and 37 K. pneumoniae (DC: 34; HC: 3), from 251 rectal swabs (DC: 219; HC: 32) were investigated for extended-spectrum beta-lactamase (ESBL), AmpC type β-lactamase and carbapenemase production, antimicrobial susceptibility profile, biofilm production, and efflux pump activity. Fifty-five MDR isolates were ESBL producers (ESBLPs) (DC: 50; HC: 5) and ESBLPs from DC were coresistant to multiple antibiotics. The blaCTX-M gene (50) was the most frequently detected β-lactamases followed by blaAmpC (22), blaTEM1 (13), blaCMY-6 (6), blaOXA1 (5), blaPER (2), blaDHA, and blaFOX and blaSHV12 (1 each). Plasmid-mediated quinolone resistance determinants qnrB, qnrS, qnrA, and qepA were detected in 18, 16, 2, and 3 isolates, respectively. Twenty three isolates revealed mutation in gyrA and parC genes. Tetracycline-resistance markers tetA, tetB, tetC, and tetE were detected in 33, 10, 3, and 2 isolates, respectively. Only one of the 41 imipenem-resistant isolates harbored blaNDM-5 and two were colistin-resistant. Altogether, 20 MDR isolates were strong biofilm producers and 19 harbored different virulence factors. This is the first ever report from India on the presence of MDR Enterobacteriaceae with resistance to even last-resort antimicrobials in the bovine diarrhea.

Distribution of Antibiotic-Resistant Enterobacteriaceae Pathogens in Potable Spring Water of Eastern Indian Himalayas: Emphasis on Virulence Gene and Antibiotic Resistance Genes in Escherichia coli

Every year millions of people die due to fatal waterborne diseases around the world especially in developing countries like India. Sikkim, a northeastern state of India, greatly depends on natural water sources. About 80% of the population of Sikkim depends on natural spring water for domestic as well as agricultural use. Recent waterborne disease outbreaks in the state raises a concerning question on water quality. In this study, we analyzed water quality especially for the detection of Enterobacteriaceae members from four districts of the state. Isolation with selective culture media techniques and taxonomic characterization of Enterobacteriaceae bacteria with 16S rRNA gene showed the prevalence of Escherichia coli (37.50%), Escherichia fergusonii (29.41%), Klebsiella oxytoca (36.93%), Citrobacter freundii (37.92%), Citrobacter amalonaticus (43.82%), Enterobacter sp. (43.82%), Morganella morganii (43.82%), Hafnia alvei (32.42%), Hafnia paralvei (38.74%), and Shigella flexneri (30.47%) in the spring water of Sikkim. Antibiotic susceptibility test (AST) showed resistance of the isolates to common antibiotics like ampicillin, amoxicillin as well as to third generation antibiotics like ceftazidime and carbapenem. None of the isolates showed resistance to chloramphenicol. E. coli isolated from spring water of Sikkim showed presence of different virulence genes such as stx1 (81.81%), elt (86.66%), and eae (66.66%) along with resistance gene for ampicillin (CITM) (80%), quinolones (qnrB) (44.44%), tetracycline (tetO) (66.66%), and streptomycin (aadA1) (66.66%). The data indicates a high incidence rate of multiple antibiotic resistant enteric bacteria in the spring water of Sikkim. Additionally, the presence of enteric bacteria in the water samples indicates widespread fecal contamination of the spring water.

A review on the consumption of vended fruits: microbial assessment, risk, and its control

Fruits are very beneficial to health and their consumption has been recommended in daily diets. However, when fresh fruits are harvested and processed into sliced ready-to-eat or vended forms for sale, hygienic procedures are neglected. Thus, they are easily infested by pathogens. In addition, uneducated vendors who sell these fruits often display or hawk them on the streets in contaminated containers, utensils, or dirty environments. This poses a great threat to the health of consumers. In the light of this realization, some microbial assessments have been carried out to ascertain the safety of these vended fruits, thus making it a necessity to exploit the outcomes of some of these microbial assessments on vended fruits in order to sensitize the consumers on the effect of their consumption and mitigate risk by improving their quality. This will assist to lower certain health concerns, an outbreak of diseases, and death.

Prevalence of Multi-Antibiotic Resistant Escherichia coli and Klebsiella species obtained from a Tertiary Medical Institution in Oyo State, Nigeria

Background: The development of multi-antibiotic resistant bacteria, especially Gram-negative bacteria which are the major cause of hospital-acquired infections worldwide, had been increasing. Escherichia coli and Klebsiella sp. had become more resistant to different classes of antibiotics, and the treatment of infections caused by these bacteria had developed into a challenge in both developed and developing countries. This study had determined the multi-antibiotic resistance (MAR) patterns of Escherichia coli and Klebsiella sp. isolated from clinical inpatient and outpatient samples. Method: The present study had used 50 E. coli and 48 Klebsiella sp. isolates. Antibiotic susceptibility test had been carried out by using disk diffusion method, and the interpretation of results of the zones of inhibition had accorded with Clinical Laboratory Standards Institute (CLSI). The antibiotics used had included the following: streptomycin, ciprofloxacin, erythromycin, nitrofurantoin, amikacin, gentamicin, ofloxacin, cefepime, oxacillin, colistin sulfate, cefotaxime, ceftazidime, pefloxacine, and cloxacillin. Results:E. coli and K. pneumoniae had shown high-resistance patterns. E. coli had exhibited high resistance against cloxacillin (96%), oxacillin (96%), erythromycin (88%), and most especially streptomycin (98%). Similarly, K. pneumoniae had presented a high resistance to streptomycin (88%), cloxacillin (92%), oxacillin (92%), and colistin (92%). E. coli had presented the highest multidrug resistance with a MAR index of 1.00. A total of 17 E. coli isolates had shown resistance to the 14 antibiotics tested. Conclusion:E. coli and Klebsiella sp. in clinical isolates in outpatients and inpatients in Ibadan, Western Nigeria had demonstrated high antimicrobial resistance. Thus, such condition should be considered a major public health concern, and measures must be taken to establish the sources and drivers of this problem.

An in silico analysis of acquired antimicrobial resistance genes in Aeromonas plasmids

Sequences of 105 Aeromonas species plasmids were probed for acquired anti-microbial resistance (AMR) genes using a bioinformatics approach. The plasmids showed no positive linear correlation between size and GC content and up to 55 acquired AMR genes were found in 39 (37%) plasmids after in silico screening for resistance against 15 antibiotic drug classes. Overall, potential multiple antibiotic resistance (p-MAR) index ranged from 0.07 to 0.53. Up to 18 plasmids were predicted to mediate multiple drug resistance (MDR). Plasmids pS121-1a (A. salmonicida), pWCX23_1 (A. hydrophila) and pASP-a58 (A. veronii) harboured 18, 15 and 14 AMR genes respectively. The five most occurring drug classes for which AMR genes were detected were aminoglycosides (27%), followed by beta-lactams (17%), sulphonamides (13%), fluoroquinolones (13%), and phenicols (10%). The most prevalent genes were a sulphonamide resistant gene Sul1, the gene aac (6')-Ib-cr (aminoglycoside 6'-N-acetyl transferase type Ib-cr) resistant to aminoglycosides and the blaKPC-2 gene, which encodes carbapenemase-production. Plasmid acquisition of AMR genes was mainly inter-genus rather than intra-genus. Eighteen plasmids showed template or host genes acquired from Pseudomonas monteilii, Salmonella enterica or Escherichia coli. The most occurring antimicrobial resistance determinants (ARDs) were beta-lactamase, followed by aminoglycosides acetyl-transferases, and then efflux pumps. Screening of new isolates in vitro and in vivo is required to ascertain the level of phenotypic expression of colistin and other acquired AMR genes detected.

Okoh A. Campylobacteriosis Agents in Meat Carcasses Collected from Two District Municipalities in the Eastern Cape Province, South Africa

Raw meats are sometimes contaminated with Campylobacter species from animal faeces, and meats have repeatedly been implicated in foodborne infections. This study evaluated the prevalence, virulence genes, antimicrobial susceptibility patterns, and resistance gene determinants in Campylobacter species isolated from retailed meat carcasses. A total of 248 raw meat samples were collected from butcheries, supermarkets, and open markets; processed for enrichment in Bolton broth; and incubated at 42 °C for 48 h in 10% CO2. Thereafter, the broths were streaked on modified charcoal cefoperazone deoxycholate agar (mCCDA) plates and incubated at the same conditions and for the same amount of time. After incubation, colonies were isolated and confirmed by Polymerase chain reaction using specific oligonucleotide sequences used for the identification of the genus Campylobacter, species, and their virulence markers. The patterns of antimicrobial resistance profiles of the identified isolates were studied by disk diffusion method against 12 antibiotics, and relevant resistance genes were assessed by PCR. From culture, 845 presumptive Campylobacter isolates were obtained, of which 240 (28.4%) were identified as genus Campylobacter. These were then characterised into four species, of which C. coli had the highest prevalence rate (22.08%), followed by C. jejuni (16.66%) and C. fetus (3.73%). The virulence genes detected included iam (43.14%), cadF (37.25%), cdtB (23.53%), flgR (18.63%), and flaA (1.96%), and some of the isolates co-harboured two to four virulence genes. Of the 12 antibiotics tested, the highest phenotypic resistance displayed by Campylobacter isolates was against clindamycin (100%), and the lowest level of resistance was observed against imipenem (23.33%). The frequency of resistance genes detected included catll (91.78%), tetA (68.82%), gyra (61.76%), ampC (55%), aac(3)-IIa (aacC2)a (40.98%), tetM (38.71%), ermB (18.29%), tetB (12.90%), and tetK (2.15%). There is a high incidence of Campylobacter species in meat carcasses, suggesting these to be a reservoir of campylobacteriosis agents in this community, and as such, consumption of undercooked meats in this community is a potential health risk to consumers.

Antimicrobial and Disinfectant Susceptibility of Salmonella Serotypes Isolated from Swine Slaughterhouses

Salmonella remains one of the most common foodborne pathogens worldwide, and its resistance to antimicrobials and disinfectants has increased considerably over the years. Thus, monitoring its resistance to products commonly used in swine production is indispensable for the development of strategies to reduce the occurrence of bacterial resistance. In this context, our aim was to detect Salmonella at different points in swine slaughterhouses, identify the main serotypes, and evaluate their resistance to disinfectants and antimicrobials used in swine production. Salmonella at the processing plants was detected by conventional microbiology. Salmonella strains were tested for susceptibility to peracetic acid (0.5% and 1%), quaternary ammonium (0.5%), and seven antimicrobials. Twenty-eight percent of the samples were positive for Salmonella, with the most identified serotypes being Salmonella Derby, Salmonella Typhimurium, and monophasic Salmonella Typhimurium. All tested strains were susceptible to both concentrations of peracetic acid, but only 28% were susceptible to quaternary ammonium. Sixteen percent of the strains were susceptible to all tested antimicrobials. Only enrofloxacin was efficient in inhibiting the growth of all strains. The highest number of non-susceptible strains was to amoxicillin, followed by chloramphenicol, florfenicol, and doxycycline. Thirty-six percent of the strains were classified as multidrug-resistant. Salmonella were detected in all slaughtering processes, and important serotypes were recovered, including Salmonella Typhimurium, Salmonella Derby, monophasic Salmonella Typhimurium, and Salmonella Infantis. We observed high rates of resistance to quaternary ammonium and to important antimicrobial agents. Salmonella Typhimurium and Salmonella Infantis were the most resistant serotypes.

Antibiotic Resistance in Staphylococcus aureus from Poultry and Poultry Products in uMgungundlovu District, South Africa, Using the "Farm to Fork" Approach

Background: This study determined the prevalence and antibiotic susceptibility profiles of Staphylococcus aureus isolated from selected critical control points (farm, transport, abattoir, and retail product) in an intensive poultry production system in the uMgungundlovu District, South Africa, using the "farm to fork" approach. Materials and Methods: Three hundred eighty-four samples from poultry and poultry products were examined across the "farm to fork" continuum for S. aureus using selective media, biochemical tests, and API Staph kit and confirmed by polymerase chain reaction identification of the nuc gene. Antibiotic susceptibility testing of the isolates was determined by the Kirby-Bauer disc diffusion method to 19 antimicrobials and to vancomycin by the broth microdilution technique. Results: The overall prevalence rate of S. aureus was 31.25% (n = 120/384), distributed across the continuum: farm site (40), transport (15), abattoir (30), and retail point (35). The isolates were resistant to tetracycline (61.67%), penicillin G (55.83%), erythromycin (54.17%), clindamycin (43.33%), doxycycline (36.67%), ampicillin (34.17%), moxifloxacin (30.83%), amikacin (30.83%), trimethoprim-sulfamethoxazole (30.00%), and levofloxacin (23.33%). A 100% susceptibility to tigecycline, teicoplanin, vancomycin, nitrofurantoin, chloramphenicol, and linezolid was observed in all isolates. The rate of multidrug resistance and the multiple antibiotic resistance index of the strains were 39.17% and 0.23%, respectively. The isolates showed similar patterns of resistance to commonly used growth promoters and antibiotics in veterinary and human medicine belonging to the same class. Conclusion: It is evident that the different antibiotics and growth promoters used in poultry production are exerting selection pressure for the emergence and co-selection of antibiotic-resistant bacteria in the production system, necessitating efficient antibiotic stewardship guidelines to streamline their use.

Antimicrobial activity and mechanism of action of a novel peptide present in the ecdysis process of centipede Scolopendra subspinipes subspinipes

One of the most important cellular events in arthropods is the moulting of the cuticle (ecdysis). This process allows them to grow until they reach sexual maturity. Nevertheless, during this stage, the animals are highly exposed to pathogens. Consequently, it can be assumed that arthropods counter with an efficient anti-infective strategy that facilitates their survival during ecdysis. Herein, we characterized a novel antimicrobial peptide called Pinipesin, present in the exuviae extract of the centipede Scolopendra subspinipes subspinipes. The antimicrobial activity of Pinipesin was tested. The haemolytic activity of the peptide was evaluated and its possible mechanism of action was investigated. Identification was carried out by mass spectrometry analysis. Pinipesin displayed potent antimicrobial effects against different microorganisms and showed low haemolytic effects against human erythrocytes at high concentrations. It has a monoisotopic mass of 1213.57 Da, its sequence exhibited high similarity with some cuticular proteins, and it might act intracellularly by interfering with protein synthesis. Our data suggest that Pinipesin might be part of a prophylactic immune response during the ecdysis process of centipedes. Therefore, it is a promising candidate for the development of non-conventional antibiotics that could help fight infectious diseases and represents an exciting discovery for this taxon.

Convergent evolution in bacteria from multiple origins under antibiotic and heavy metal stress, and endophytic conditions of host plant

The focus of this work is to study the convergent evolution in bacteria from multiple origins under antibiotic and heavy metal stress, and endophytic conditions of host plant cultivated on the Yamuna river bank. Forty-one endophytic bacteria (EB) were isolated from green leafy vegetables (GLV's) and were found to be resistant to a wide range of antibiotics (AB) and heavy metals (HM) tested. Further, they showed susceptibility to Quinolones group of antibiotics, and the HM, Cadmium, Chromium, and Mercury. Twenty-seven percent of these bacteria endowed with Class I integron. The probability of co-existence of HM resistance with β‑lactams was higher, whereas quinolones group of AB recorded lesser values. These EB owned a wide array of beneficial traits, through which they improved the plant health under HM and salt stress conditions. Bacterial identity revealed the association of both plant beneficial and human pathogenic bacteria as an endophyte with GLV's. Principal component analysis showed a pattern of convergent evolution irrespective of their origin. In conclusion, under the selection pressure of AB and HM, the susceptible EB population may reduce with time and the resistant native/introduced bacteria might survive. The vertical and horizontal gene transfer between introduced and native bacteria is the crucial factor in enhancing their fitness along with the host plant to survive under abiotic stress conditions.

Environmental strains potentially contribute to the proliferation and maintenance of antibiotic resistance in drinking water: A case study of Cupriavidus metallidurans

Fitness costs of antibiotic resistance detrimentally affect the fate of resistance carriers. Intriguingly, numerous antibiotic resistant bacteria (ARB) have been detected despite the low concentration of antibiotics in drinking water. To reveal the causes of this discrepancy, we investigated the fitness cost of antimicrobial resistance in strain Cupriavidus metallidurans CR2 which was isolated from a drinking water filter. Pure culture and 1:1 competitive experiments were established at different nutrient levels. The growth rates of strain C. metallidurans CR2 significantly decreased when pure cultured under poor nutrient conditions, however, the multi-resistance and the resistance megaplasmids were well maintained. Competitiveness costs were observed in C. metallidurans when separately co-cultured with environmentally-isolated Flectobacillus BS1 and Pseudomonas sp. S3, while C. metallidurans was outnumbered by the rivals with a decrease of 1-2 logs. But the majority of C. metallidurans retained the plasmids under oligotrophic conditions even after 144 h (1.99 and 0.199 mg C/L). Additionally, C. metallidurans CR2 has a higher tolerance to chlorine and chloramine, which potentially could become prevalent in the subsequent distribution systems other than drinking water treatment plant. As a potential pathogen, the prevalence of Cupriavidus metallidurans in drinking water would also pose certain threats to human health.

Five-Year Antimicrobial Susceptibility of Pseudomonas aeruginosa from a Local Tertiary Hospital in Bacolod City, Philippines

Over five years, a total of 646 P. aeruginosa isolates was acquired from different clinical specimens and their resistance to the commonly used anti-pseudomonal antibiotics was determined. The majority of the isolates were from respiratory (60.99%) and urinary sources (23.22%) while the least came from transudates and exudates (2.01%). Most of the samples were acquired from older adults (77.55%), most of whom were admitted (67.03%). Amikacin was found to be the most effective drug with a resistance rate of 7.5%, followed by piperacillin/tazobactam (8.5%) and gentamicin (13.5%). On the other hand, 26.7% of the isolates were resistant to levofloxacin. Almost 100% of the isolates were screened positive for AmpC production, which may suggest inducible resistance against expanded spectrum beta-lactamase. Furthermore, for the last three years, P. aeruginosa isolates from this area have been noted to have decreasing resistance only to aztreonam and gentamicin. Also, for five years, a mean MAR index of 0.17 was noted which indicates either proper antibiotic use or most isolates did not come from high-risk areas. Moreover, there was no significant difference in the resistance of P. aeruginosa when compared by specimen source (p = 0.662), but significant when compared by year band (p = 0.02).

Association study of multiple antibiotic resistance and virulence: a strategy to assess the extent of risk posed by bacterial population in aquatic environment

The present study explored the association between multiple antibiotic resistance (MAR) index and virulence index to determine what percent of environmental antibiotic-resistant (eARB) bacteria could pose threat as potential pathogen. 16srRNA-based sequencing of 113 non-duplicate isolates identified majority of them to be gram negative belonging to Enterobacter, Pseudomonas, Aeromonas, Proteus, Acinetobacter, and Klebsiella. Statistical comparison of MAR indices of the abovementioned genera indicated differences in the median values among the groups (p < 0.001). Pair-wise multiple comparison by Dunn's method indicated significant difference in MAR indices (p < 0.05), based on which multiple antibiotic resistance phenotype could be ranked in the order Pseudomonas > Klebsiella = Acinetobacter > Proteus > Aeromonas > Enterobacter. Association between MAR index and virulence index revealed that 25% of isolates in the population under study posed high threat to human/animal or both; out of which 75% isolates belonged to genus Pseudomonas. Based on observations of comparative analysis of the six gram-negative genera, it could be concluded that Pseudomonas isolates from environment pose significantly high threat as potential pathogens while Enterobacter isolates posed no threat.