The Bacteriology and Its Virulence Factors in Neonatal Infections: Threats to Child Survival Strategies

Biotransformation of diclofenac by isolated super-degrader Pseudomonas sp. DCα4: Postulated pathways, and attenuated ecotoxicological effects

Significant concentrations of emerging xenobiotics, like diclofenac (DCF), possessing severe irreversible eco-toxicological threats, has been detected in aquatic systems worldwide, raising the concerns. This present investigation is intended to explore an efficient solution to support the existing wastewater treatment policies to handle DCF contamination by bacteria-mediated biotransformation. DCF-tolerant bacterial strains were isolated from pharmaceutical wastewater and selected based on their non-virulence nature and degradation ability. Among those, Pseudomonas sp. DCα4 was found to be the most dominant DCF degrader exhibiting 99.82% removal of DCF confirmed by HPLC after optimization of temperature at 30.02 °C, pH at 6.9, inoculum of 4.94%, and time 68.02 h. The degradation kinetics exhibited the process of DCF degradation followed a first-order kinetics with k of 0.108/h and specific degradation rate of 0.013/h. Moreover, the enzyme activity study indicated predominant hydrolase activity in the DCF treatment broth of DCα4, implying hydrolysis as the main force behind DCF biotransformation. HRMS analysis confirmed the presence of 2-hydroxyphenylacetic acid, 1,3-dichloro,2-amino, 5-hydroxybenzene, and benzylacetic acid as major intermediates of DCF biodegradation indicating non-specific hydrolysis of DCF. Whole genome analysis of most related strains which were confirmed by near full 16S rRNA gene sequence homology study, predicted involvement of different N-C bond hydrolase producing genes like puud, atzF, astB, nit1, and nylB. The ecotoxicological study using Aliivibrio fischeri exhibited 47.51% bioluminescence inhibition by DCF-containing broth which was comparable to the same caused by 1 mg/mL of K2Cr2O7 whereas remediated broth exhibited only 0.51% inhibition implying reduction of the ecotoxic load caused by DCF contamination. Cost analysis revealed that possible integration of the process with existing ones would increase per litre expense by $0.45. These results indicated that the described process of DCF biodegradation using the super-degrader DCα4 would be an advancement of existing pharmaceutical wastewater treatment processes for DCF bioremediation.

Biofilm-Mediated Heavy Metal Removal from Aqueous System by Multi-Metal-Resistant Bacterial Strain Bacillus sp. GH-s29

Worldwide ever-augmenting urbanization, modernization, and industrialization have contributed to the release of pernicious compounds and a variety of pollutants into the environment. The pollutants discharged due to industrialization are of global concern. Industrial waste and effluent are comprised of hazardous organic and inorganic chemicals including heavy metals which pose a significant threat to the environment and may bring about numerous diseases or abnormalities in human beings. This brings on greater urgency for remediation of these polluted soil and water using sustainable approaches and mechanisms. In the present research, a multi-metal-resistant, gram-positive, non-virulent bacterial strain Bacillus sp. GH-s29 was isolated from contaminated groundwater of Bhojpur district, Bihar, India. The strain had the potential to develop a biofilm that was able to remediate different heavy metals [arsenic, cadmium, and chromium] from individual and multi-heavy metal solutions. Maximum removal for As (V), Cd (II), and Cr (VI) from individual-metal and the multi-metal solution was observed to be 73.65%, 57.37%, 61.62%, and 48.92%, 28.7%, and 35.46%, respectively. SEM-EDX analysis revealed the sequestration of multi-heavy metals by bacterial biofilm. Further characterization by FTIR analysis ensured that the presence of negatively charged functional groups on the biofilm-EPS such as hydroxyl, phosphate, sulfate, and carboxyl helps in binding to the positively charged metal ions. Thus, Bacillus sp. GH-s29 proved to be an effective and economical alternative for different heavy metal remediation from contaminated sites.

Antibiotic susceptibility of Escherichia coli isolated from neonates admitted to neonatal intensive care units across China from 2015 to 2020

Background

Escherichia coli is one of the most common pathogens causing neonatal infections. Recently, the incidence and drug resistance of E. coli have increased, posing a major threat to neonatal health. The aim of this study was to describe and analyze the antibiotic resistance and multilocus sequence typing (MLST) characteristics of E. coli derived from infants admitted to neonatal intensive care units (NICUs) across China.

Methods

In this study, 370 strains of E. coli from neonates were collected. E. coli isolated from these specimens were subjected to antimicrobial susceptibility testing (by broth microdilution method) and MLST.

Results

The overall resistance rate was 82.68%, with the highest rate of methicillin/sulfamethoxazole (55.68%) followed by cefotaxime (46.22%). Multiple resistance rate was 36.74%, 132 strains (35.68%) had extended-spectrum β-lactamase (ESBL) phenotype and 5 strains (1.35%) had insensitivity to the tested carbapenem antibiotics. The resistance of E. coli isolated from different pathogenicity and different sites of infections varied, strains derived from sputum were significantly more resistant to β-lactams and tetracyclines. Currently, the prevalence spectrum in NICUs was dominated by ST1193, ST95, ST73, ST69 and ST131 across China. And the multidrug resistance of ST410 was the most severe. ST410 had the highest resistance rate to cefotaxime (86.67%), and its most common multidrug resistance pattern was β-lactams + aminoglycosides + quinolones + tetracyclines + sulfonamides.

Conclusions

Substantial proportions of neonatal E. coli isolates were severely resistant to commonly administered antibiotics. MLST results can suggest the prevalent characteristics of antibiotic resistance in E. coli with different ST types.

Review and analysis of the overlapping threats of carbapenem and polymyxin resistant E. coli and Klebsiella in Africa

BACKGROUND

Carbapenem-resistant Enterobacterales are among the most serious antimicrobial resistance (AMR) threats. Emerging resistance to polymyxins raises the specter of untreatable infections. These resistant organisms have spread globally but, as indicated in WHO reports, the surveillance needed to identify and track them is insufficient, particularly in less resourced countries. This study employs comprehensive search strategies with data extraction, meta-analysis and mapping to help address gaps in the understanding of the risks of carbapenem and polymyxin resistance in the nations of Africa.

METHODS

Three comprehensive Boolean searches were constructed and utilized to query scientific and medical databases as well as grey literature sources through the end of 2019. Search results were screened to exclude irrelevant results and remaining studies were examined for relevant information regarding carbapenem and/or polymyxin(s) susceptibility and/or resistance amongst E. coli and Klebsiella isolates from humans. Such data and study characteristics were extracted and coded, and the resulting data was analyzed and geographically mapped.

RESULTS

Our analysis yielded 1341 reports documenting carbapenem resistance in 40 of 54 nations. Resistance among E. coli was estimated as high (> 5%) in 3, moderate (1-5%) in 8 and low (< 1%) in 14 nations with at least 100 representative isolates from 2010 to 2019, while present in 9 others with insufficient isolates to support estimates. Carbapenem resistance was generally higher among Klebsiella: high in 10 nations, moderate in 6, low in 6, and present in 11 with insufficient isolates for estimates. While much less information was available concerning polymyxins, we found 341 reports from 33 of 54 nations, documenting resistance in 23. Resistance among E. coli was high in 2 nations, moderate in 1 and low in 6, while present in 10 with insufficient isolates for estimates. Among Klebsiella, resistance was low in 8 nations and present in 8 with insufficient isolates for estimates. The most widespread associated genotypes were, for carbapenems, blaOXA-48, blaNDM-1 and blaOXA-181 and, for polymyxins, mcr-1, mgrB, and phoPQ/pmrAB. Overlapping carbapenem and polymyxin resistance was documented in 23 nations.

CONCLUSIONS

While numerous data gaps remain, these data show that significant carbapenem resistance is widespread in Africa and polymyxin resistance is also widely distributed, indicating the need to support robust AMR surveillance, antimicrobial stewardship and infection control in a manner that also addresses broader animal and environmental health dimensions.

Lipopolysaccharide downregulates the expression of ZO-1 protein through the Akt pathway

Background

Neonatal bacterial meningitis is a common neonatal disease with high morbidity, and can cause serious sequelae when left untreated. Escherichia coli is the common pathogen, and its endotoxin, lipopolysaccharide (LPS) can damage the endothelial cells, increasing the permeability of the blood-brain barrier (BBB), leading to intracranial inflammation. However, the specific mechanism of bacterial meningitis induced by LPS damaging BBB remains unclear. In this study, the mouse brain microvascular endothelial (bEND.3) cells were used as a research object to investigate whether LPS damage BBB through the PI3K/Akt pathway.

Methods

The bEND.3 cells were stimulated with different concentrations of LPS for 12 h, and the expression of tight junction proteins (ZO-1, claudin-5, occludin) was detected using western blotting. The cells were challenged with the same concentration of LPS (1ug/ml) across different timepoints (0, 2 h, 4 h, 6 h, 12 h, 24 h). Expression of TJ proteins and signal pathway molecules (PI3K, p-PI3K, Akt, p-Akt) were detected. The distribution of ZO-1 in bEND.3 cells were detected by immunofluorescence staining.

Results

A negative correlation is observed between ZO-1 and LPS concentration. Moreover, a reduced expression of ZO-1 was most significant under 1 ug/ml of LPS, and the difference was statistically significant (P < 0.05). Additionally, there is a negative correlation between ZO-1 and LPS stimulation time. Meanwhile, the expression of claudin-5 and occludin did not change significantly with the stimulation of LPS concentration and time. The immunofluorescence assay showed that the amount of ZO-1 on the surface of bEND.3 cells stimulated with LPS was significantly lower than that of the control group. After LPS stimulation, p-Akt protein increased at 2 h and peaked at 4 h. The titer of p-PI3K did not change significantly with time.

Conclusion

LPS can downregulate the expression of ZO-1; however, its effect on claudin-5 and occludin is minimal. Akt signal pathway may be involved in the regulation of ZO-1 expression induced by LPS in bEND.3 cells.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-022-07752-1.

The In Vitro Antimicrobial and Antibiofilm Activities of Lysozyme against Gram-Positive Bacteria

Objective

To analyze the in vitro antibacterial and antibiofilm activities of lysozyme (LYS) and its combination with various drugs against Gram-positive bacteria (GPB, n = 9), thus to provide an exploration direction for drug development.

Methods

The minimum inhibitory concentrations (MICs) of linezolid (LZD), amikacin (AMK), ceftriaxone/sulbactam (CRO/SBT), cefotaxime/sulbactam (CTX/SBT), piperacillin/sulbactam (PIP/SBT), doxycycline (DOX), levofloxacin (LVX), amoxicillin/clavulanate potassium (7 : 1, AK71), imipenem (IPM), azithromycin (AZM), and their combinations with LYS were determined with tuber twice dilution. The antimicrobial and antibiofilm activities of LYS, AZM, LVX, and their combinations with others were evaluated through MTT and crystal violet assay.

Results

High-dose LYS (30 μg/mL) combined with PIP/SBT and AK71, respectively, showed synergistic antibacterial activities against methicillin-resistant Staphylococcus aureus (MRSA), while it showed no synergistic activities when combined with other drugs. LYS and AZM inhibited the biofilm formation of one MRSA strain, but they and LVX had no similar activities against methicillin-resistant Staphylococcus epidermidis (MRSE) or vancomycin-resistant Enterococcus faecium (VREF). Particularly, LYS increased the permeability of biofilms of MRSA 33 and exhibited antibiofilm activities against MRSA 31 (inhibition rate = 38.1%) and MRSE 61 (inhibition rate = 46.6%). The combinations of PIP/SBT+LYS, AMK+LYS, and LZD+LYS showed stronger antibiofilm activities against MRSA 62, MRSE 62, MRSE 63, and VREF 11.

Conclusion

The antimicrobial and antibiofilm activities of LYS against MRSA were better than AZM, while that of LYS against MRSE and VREF, respectively, was similar with AZM and LVX.

Probiotic Characteristics of Lactobacillus brevis KT38-3 Isolated from an Artisanal Tulum Cheese

Probiotics are living microorganisms that, when administered in adequate amounts, provide a health benefit to the host and are considered safe. Most probiotic strains that are beneficial to human health are included in the “Lactic acid bacteria” (LAB) group. The positive effects of probiotic bacteria on the host’s health are species-specific and even strain-specific. Therefore, evaluating the probiotic potential of both wild and novel strains is essential. In this study, the probiotic characteristics of Lactobacillus brevis KT38-3 were determined. The strain identification was achieved by 16S rRNA sequencing. API-ZYM test kits were used to determine the enzymatic capacity of the strain. L. brevis KT38-3 was able to survive in conditions with a broad pH range (pH 2–7), range of bile salts (0.3%–1%) and conditions that simulated gastric juice and intestinal juice. The percentage of autoaggregation (59.4%), coaggregation with E. coli O157:H7 (37.4%) and hydrophobicity were determined to be 51.1%, 47.4%, and 52.7%, respectively. L. brevis KT38-3 produced β-galactosidase enzymes and was able ferment lactose. In addition, this strain was capable of producing antimicrobial peptides against the bacteria tested, including methicillin and/or vancomycin-resistant bacteria. The cell-free supernatants of the strain had high antioxidant activities (DPPH: 54.9% and ABTS: 48.7%). Therefore, considering these many essential in vitro probiotic properties, L. brevis KT38-3 has the potential to be used as a probiotic supplement. Supporting these findings with in vivo experiments to evaluate the potential health benefits will be the subject of our future work.

Bacteriological profile and antibiotic resistance in newborn infants with possible community-acquired neonatal sepsis in Khartoum State, Sudan

Neonatal sepsis is a leading cause of morbidity and mortality, and knowledge of bacterial patterns and susceptibility to antibiotics is essential to design therapeutic guidelines. To determine the bacterial aetiology and antibiotic resistance patterns in neonatal sepsis, a prospective, cross-sectional, hospital-based study was conducted in a large paediatric emergency hospital in Khartoum State, Sudan, over a 6-month period. All newborn infants with a clinical diagnosis of sepsis were included in the study and had a blood sample collected for culture and sensitivity. The World Health Organization case definition of neonatal sepsis in conjunction with the Integrated Management of Childhood Illnesses criteria was used to select patients. A total of 170 newborn infants fulfilled the study inclusion criteria. The median age at presentation was 4-7 days and blood culture was positive in 31%. Early-onset neonatal sepsis was present in 30% of cases, while 70% were late-onset. Gram-positive organisms accounted for 58% of the total isolates, and 38% were Gram-negative organisms. Staphylococcus aureus was the most prevalent organism (55% of all isolates) and 72% of these were methicillin-resistant which showed 100% sensitivity to vancomycin and 90% to gentamycin. Pseudomonas aeruginosa was the commonest Gram-negative organism in both early and late-onset sepsis and the second commonest isolated organism, accounting for 19% of cases. All Gram-negative organisms were 100% sensitive to imipenem, meropenem and ciprofloxacin. Both Gram-positive and Gram-negative organisms were highly resistant to benzylpenicillin and cefotaxime, the commonly used empiric antibiotics in neonatal sepsis.

Probiotic Potential and Gluten Hydrolysis Activity of Lactobacillus brevis KT16-2

Celiac disease (CD) is a chronic autoimmune disease that occurs in genetically predisposed individuals. Gluten-hydrolyzing probiotic bacteria are promising for alleviating symptoms in individuals with CD. Therefore, in this study, the gluten hydrolysis ability and probiotic potential of Lact. brevis KT16-2 were determined. Lact. brevis KT16-2 formed proteolysis zones on gluten and gliadin agar plates, in which gluten and gliadin were used as the only nitrogen sources. SDS-PAGE analysis showed that Lact. brevis KT16-2 completely hydrolyzed peptides ranging from 28 to 66 kDa in 8 h. Then, the survival of the strain in bile salts, in simulated gastric juice and at low pH was determined. Additionally, the antioxidant and antimicrobial substance production, autoaggregation, hydrophobicity and antibiotic resistance of the strain were investigated. API-ZYM test kits were used to determine the enzymatic capacity of the strain. Lact. brevis KT16-2 had the ability to hydrolyze wheat gluten. It was able to survive in a broad pH range (pH 2-8), in bile salts (0.3-1%), and in simulated gastric juice. It had the ability to autoaggregate (59.4%), and the hydrophobicity (52.7%) of the strain was determined. In addition, this strain was capable of producing antimicrobial peptides against test bacteria, including antibiotic-resistant bacteria. Cell-free supernatants (CFS) of the strain had high antioxidant activity (DPPH-71.0% and ABTS-54.1%). The results of this study suggest that Lact. brevis KT16-2, which can hydrolyze gliadin and has many essential probiotic properties, has the potential to be used as a probiotic supplement for individuals with CD.

Pharmaceutical Quality of Selected Metronidazole and Ciprofloxacin Infusions Marketed in South Eastern Nigeria

Background

Pharmaceutical products need to be of good quality and it is even more critical when it comes to life saving medicaments like infusions.

Objective

This research surveyed the quality fitness of some ciprofloxacin and metronidazole infusion samples marketed in South-eastern of Nigeria.

Methods

Using Official Compendial methods, microbiological quality, active pharmaceutical ingredients quantitation, pH and particle count tests were evaluated on eighty infusion bottles (from eight pharmaceutical companies) of each of the two drugs.

Results

Out of the sixteen brands tested, 2 metronidazole brands and 1 ciprofloxacin brand (representing 18.75% of the total 16 brands/makes) were contaminated while the remaining 13 brands (81.25%) were found sterile. The active pharmaceutical ingredients quantitative assay showed that all the brands of ciprofloxacin infusion were between the 95% and 105% limit of label claim while one metronidazole brand has <95–110% limit label claim. Six brands each of the two drugs evaluated fall below the acceptable pH range [ciprofloxacin (3.5–4.6) and metronidazole (4.8–5.2)], while the other two brands of both drugs passed the test. In the antibacterial study, Pseudomonas aeruginosa and Escherichia coli were susceptible to the ciprofloxacin (5 µg). However, Salmonella typhi recorded inhibition zone diameters within resistant and intermediate range. Peptostrepococcus spp was susceptible (at minimum inhibitory concentrations of 100 µg/mL) to all the brands of metronidazole, while none of the brands were effective on Lactobacillus spp. All the brands passed the test for particulate contamination. The particles size range was <10µm.

Conclusion

About eighty-one percent (81.25%) of the infusions have acceptable good microbiological quality. However, 18.75% that failed the tests is a concern knowing that these are lifesaving products.

A paper-based conductive immunosensor for the determination of Salmonella Typhimurium

We report for the first time a highly sensitive and rapid quantitative method for the detection of Salmonella Typhimurium (S. Typhimurium) using a conductive immunosensor on a paper-based device (PAD). S. Typhimurium monoclonal antibodies (MA) were first immobilized on a paper-based device and then captured by S. Typhimurium. After an immunoreaction on the device, the polyclonal antibody-colloidal gold conjugate (PA-AuNPs) was dropped to bind with S. Typhimurium. After a complete sandwich reaction, a dark red color appeared on the paper-based device, which can be observed by the naked eye for a rapid screening test. The electrical conductivity of PA-AuNPs between the screen-printed electrodes on the paper-based device was also measured for an accurate quantitative analysis. The electrical conductivity correlated well with the concentration of S. Typhimurium, which was controlled by the amount of S. Typhimurium attached to the polyclonal antibody-colloidal gold conjugate. The device showed a linear correlation for the concentration of the S. Typhimurium in the range of 10-10⁸ CFU mL^-1 in a logarithmic plot, with an R² value of 0.9882 and a limit of detection (LOD) as low as 10 CFU mL^-1. This simple, highly sensitive, and rapid method for the S. Typhimurium detection was successfully performed within 30 min, and it can be developed into small portable measuring devices in order to facilitate preliminary screening tests.

Multi-Antibiotic Resistance and Factors Affecting Carriage of Extended Spectrum β-Lactamase-Producing Enterobacteriaceae in Pediatric Population of Enugu Metropolis, Nigeria

Extended-spectrum β-lactamase (ESBL)-producing organisms have become a serious challenge in healthcare delivery globally. The prevalence of ESBL carriage in healthy and sick children in Enugu, Nigeria, was bacteriologically investigated in this study. Four hundred and twenty-two biological samples (mid-stream urine and feces) were bacteriologically analyzed. The isolates were screened for ESBL production using Clinical and Laboratory Standards Institute (CLSI) breakpoints. The suspected ESBL producers were confirmed using double disc synergy test method. Out of the 162 isolates screened, 32 (19.8%) were confirmed as ESBL positive, with a prevalence of 25.32% among sick children in Enugu State University Teaching Hospital (ESUTH), Parklane, Enugu and 13.89% in apparently healthy children in a community setting. Klebsiella spp. and Escherichia coli had the highest prevalence of 34.6% and 28.6%, respectively; Citrobacter spp. and Enterobacter spp. were 18.2% and 16.7%, respectively. The ESBL positive isolates were resistant to sulfamethoxazole/trimethoprim (100%), tetracycline (100%), kanamycin (96.9%), nitrofurantoin (84.4%), ciprofloxacin (68.6%), and chloramphenicol (62.5%) but susceptible to meropenem (100%), colistin (56.3%), and gentamicin (50%). Klebsiella spp. had the highest ESBL occurrence among sick children while E. coli had the highest ESBL occurrence among healthy children in Enugu. All ESBL-positive isolates were multiply resistant to conventional antibiotics. The emergence and spread of β-lactamase-producing Enterobacteriaceae in hospital and community environments highlight the possibility for an infection outbreak if not checked.

Carbapenem-Resistant Enterobacteriaceae Posing a Dilemma in Effective Healthcare Delivery

The emergence and spread of Carbapenem-resistant Enterobacteriaceae (CRE) is seriously posing threats in effective healthcare delivery. The aim of this study was to ascertain the emergence of CRE at Chukwuemeka Odumegwu Ojukwu University Teaching Hospital (COOUTH) Awka. Biological samples were collected from 153 consenting patient from 5 clinics in the hospital. The isolates were identified using standard microbiological protocols. Susceptibility to meropenem was done using Kirby-Bauer disc diffusion method on Mueller Hinton Agar. A total of 153 patients were recruited in this study. About one half of those from rural, 63.64% from Sub-urban and 42.27% from urban areas had significant E. coli and Klebsiella spp infections. The male: female ratio of the Enterobacteriaceae infection was 1:1. Almost as much inpatient as outpatient study participants had the infections. The infections were observed mostly on participants with lower educational status. The unmarried individuals were most infected compared to their married counterparts. Enterobacteriaceae infection rate was 50.98%. Of this, 28.21% had CRE infection while the overall prevalence of the CRE in the studied population was 14.38% (22/153). This study shows that CRE is quickly emerging in both community and hospital environments. Klebsiella spp was the most common CRE in this hospital especially Klebsiella oxytoca. Hospitalization was a strong risk factor in the CRE infections. Rapid and accurate detection is critical for their effective management and control.

Winning the War against Multi-Drug Resistant Diarrhoeagenic Bacteria

Drug-resistant-diarrhoeagenic bacteria are currently emerging healthcare challenge. This study investigated the effects of Vernonia amygdalina, Garcinia kola, tetracycline and metronidazole combinations on such bacteria. Agar well diffusion method was employed to determine the inhibitory effects of the herbal extracts on diarrhoeagenic bacteria while Time-Kill Assay was used to determine bactericidal effects of the extracts against test isolates. Interactions between plant extracts and antibiotics were investigated using Checkerboard assay. Minimum inhibitory concentrations of the extracts against the bacterial isolates ranged between 3.125–50 mg/mL, while those of tetracycline and metronidazole ranged from 30–50 μg/mL. Synergism was observed against B. cereus and S. aureus for metronidazole + aqueous G. kola at all ratios. Generally, the combinations aqueous G. kola + ethanolic G. kola and aqueous G. kola + ethanolic V. amygdalina showed more pronounced synergism against the Staphylococcus aureus than B. cereus isolates with the fractional inhibition concentration (FIC) indices ranging from 0.32–0.95. Synergism of tetracycline + crude extracts and metronidazole combinations were more pronounced on the test isolates and especially on the Gram-negative organisms with FIC indices ranging from 0.41–0.91. Conclusion: The herbal extracts combinations and extracts–antibiotics combinations are synergistic on diarrhoeagenic bacteria at defined combination ratios.