Antibiotic Resistance in Plant Pathogenic Bacteria: Recent Data and Environmental Impact of Unchecked Use and the Potential of Biocontrol Agents as an Eco-Friendly Alternative.

The economic impact of phytopathogenic bacteria on agriculture is staggering, costing billions of US dollars globally. Pseudomonas syringae is the top most phytopathogenic bacteria, having more than 60 pathovars, which cause bacteria speck in tomatoes, halo blight in beans, and so on. Although antibiotics or a combination of antibiotics are used to manage infectious diseases in plants, they are employed far less in agriculture compared to human and animal populations. Moreover, the majority of antibiotics used in plants are immediately washed away, leading to environmental damage to ecosystems and food chains. Due to the serious risk of antibiotic resistance (AR) and the potential for environmental contamination with antibiotic residues and resistance genes, the use of unchecked antibiotics against phytopathogenic bacteria is not advisable. Despite the significant concern regarding AR in the world today, there are inadequate and outdated data on the AR of phytopathogenic bacteria. This review presents recent AR data on plant pathogenic bacteria (PPB), along with their environmental impact. In light of these findings, we suggest the use of biocontrol agents as a sustainable, eco-friendly, and effective alternative to controlling phytopathogenic bacteria.

Biosynthesis, Molecular Regulation, and Application of Bacilysin Produced by Bacillus Species.

Microbes produce a diverse range of secondary metabolites in response to various environmental factors and interspecies competition. This enables them to become superior in a particular environment. Bacilysin, a dipeptide antibiotic produced by Bacillus species, is active against a broad range of microorganisms. Because of its simple structure and excellent mode of action, i.e., through the inhibition of glucosamine 6-phosphate synthase, it has drawn the attention of researchers. In addition, it acts as a pleiotropic signaling molecule that affects different cellular activities. However, all Bacillus species are not capable of producing bacilysin. The biosynthesis of bacilysin by Bacillus species is not uniform throughout the population; specificity and heterogeneity at both the strain and species levels has been observed. This review discusses how bacilysin is biosynthesized by Bacillus species, the regulators of its biosynthesis, its importance in the host, and the abiotic factors affecting bacilysin production.

Molecular epidemiology and genetic diversity of norovirus infection in children with acute gastroenteritis in Bangladesh, 2014-2019.

Acute gastroenteritis (AGE) is one of the most common diseases in children, and it continues to be a significant cause of morbidity and mortality worldwide. Norovirus is one of the major enteropathogens associated with both sporadic diarrhea and outbreaks of gastroenteritis. This study aims to investigate genotype diversity and molecular epidemiology of norovirus in Bangladesh. A total of 466 fecal specimens were collected from January 2014 to January 2019 from children below 5 years old with AGE in Bangladesh. All samples were analyzed by reverse transcriptase polymerase chain reaction to detect norovirus, and sequence analysis was conducted if found positive. Norovirus was detected in 5.1% (24 of 466) fecal specimens. Norovirus genotype GII.7 was predominant (62.5%, 15 of 24), followed by GII.3 (37.5%, 9 of 24). Coinfection between rotavirus and norovirus was found in 7 of 24 positive cases. Diarrhea (93.7%) and dehydration (89%) were the most common symptoms in children with AGE. About 80% of the positive cases were detected in children aged under 24 months. One seasonal peak (87.5% infection) was detected in the winter. This study suggests that norovirus continues to be one of the major etiologies of children AGE in Bangladesh. This study will provide a guideline to assess the burden of norovirus infection in Bangladesh, which will assist to combat against AGE.

Prevalence of Methicillin-Resistant Staphylococcus aureus in Hospitals in Chittagong, Bangladesh: A Threat of Nosocomial Infection.

BACKGROUND: As a life threatening infectious disease, methicillin resistant Staphylococcus aureus (MRSA) infection has been turned into a global health concern recently. In a developing country like Bangladesh, the situation is vulnerable because of inadequate and inappropriate practices of control measures to prevent the spread of nosocomial infection. MATERIALS AND METHODS: In this study, 100 clinical, nonclinical, and environmental samples were collected from different hospitals in Bangladesh and examined for the detection of methicillin resistant and multidrug resistant S. aureus by cultural methods. Antibiotic sensitivity pattern of isolates was also evaluated by Kirby-Bauer disc diffusion method. RESULTS: Out of the total 100 samples, 66 isolates of S. aureus were determined. Among them, 53 isolates (80.30%) revealed a positive result for oxacillin test, but avoiding any false result, 53 oxacillin positive isolates were again examined by cefoxitin, whereas 43 isolates (65.15%) were resistant to cefoxitin and consequently confirmed as MRSA and rest of the 23 isolates (34.85%) were fixed as methicillin sensitive S. aureus. In antibiotic sensitivity test, S. aureus showed the highest (83%) resistance to gentamycin, oxacillin and cefotaxime than other antibiotics. Finally, the risk practices were assessed which are potential factors for spreading infections. CONCLUSION: Since, MRSA as well as other antibiotic resistant S. aureus are potent threat to human, therefore, we should consider it as a great concern to minimize or prevent the prevalence and adverse effects of MRSA.

Presence of Multidrug-Resistant Bacteria on Mobile Phones of Healthcare Workers Accelerates the Spread of Nosocomial Infection and Regarded as a Threat to Public Health in Bangladesh.

Recently, mobile phones have become a potent vector for the transmission of pathogens. In hospitals, the use of the mobile phones by healthcare workers in an unhygienic manner accelerates the spread of nosocomial infection. We aimed to investigate the prevalence of microbiological contamination of mobile phones belonging to clinicians in Bangladesh hospitals. From 100 samples, we identified 69 isolates of bacteria including 22 Staphylococcus aureus; 11 Pseudomonas aeruginosa; 14 Escherichia coli; 6 Salmonella typhi 6 and 16 Staphylococcus epidermidis. On the basis of antibiotic susceptibility test using 11 antibiotics, it has been observed that most of the isolated bacteria became resistant to antibiotics and compared to other isolates, isolates of S. epidermidis and S. typhi were more resistant and sensitive, respectively. About 68.8% isolates showed that their resistance capacities against ampicillin but in contrast, 56.6% isolated were susceptible to imipenem. Azithromycin and imipenem against S. aureus, gentamicin against P. aeruginosa, tetracycline and imipenem against E. coli, tetracycline against S. typhi, and S. epidermidis revealed significant antimicrobial affectivity. We found that mobile phones are potential vectors to spread antibiotic-resistant nosocomial pathogens. Based on the study, an effective disinfection practice for cellular phones used in hospitals should be introduced to prevent the potential of cross-contamination.

Evaluation of psychopharmacological and neurosafety profile of Swas Kas Chintamani Ras (SKC) in Swiss-Webster mice.

OBJECTIVES: Swas Kas Chintamani Ras (SKC) is an ayurvedic preparation indicated for respiratory diseases. Our study was aimed to determine the psychopharmacological and neurosafety profile of SKC. MATERIALS AND METHODS: Psychopharmacological effects and neurosafety profile of this drug were determined by nine complementary test methods namely, open field, locomotor activity, hole cross, hole board test, elevated plus maze, staircase, forced swimming test, and rotarod test. Male mice (Swiss-Webster strain, 20-40 g body weight) bred in the Animal House of the Department of Pharmacy, Jahangirnagar University, were used for the pharmacological experiments. RESULTS: The drug decreased total ambulation and movement in the central region and standing up behavior and lowered emotional defecation. The drug also made the mice to take a shorter time to come out of the cage. Also, animals spent less time in open arm and the movement in the closed arm and locomotors reduced (p=0.003), where a number of rearing (p=0.04) behaviour indicating possible anxiolytic activity. Also, no signs of anti-depressant activity were observed among SKC-treated group. CONCLUSION: We concluded that our drug showed no neurotoxic effect and it also showed some beneficial neuropharmacological properties.

Phylogenetic Diversity of Vibrio cholerae Associated with Endemic Cholera in Mexico from 1991 to 2008.

UNLABELLED: An outbreak of cholera occurred in 1991 in Mexico, where it had not been reported for more than a century and is now endemic. Vibrio cholerae O1 prototype El Tor and classical strains coexist with altered El Tor strains (1991 to 1997). Nontoxigenic (CTX(-)) V. cholerae El Tor dominated toxigenic (CTX(+)) strains (2001 to 2003), but V. cholerae CTX(+) variant El Tor was isolated during 2004 to 2008, outcompeting CTX(-) V. cholerae. Genomes of six Mexican V. cholerae O1 strains isolated during 1991 to 2008 were sequenced and compared with both contemporary and archived strains of V. cholerae. Three were CTX(+) El Tor, two were CTX(-) El Tor, and the remaining strain was a CTX(+) classical isolate. Whole-genome sequence analysis showed the six isolates belonged to five distinct phylogenetic clades. One CTX(-) isolate is ancestral to the 6th and 7th pandemic CTX(+) V. cholerae isolates. The other CTX(-) isolate joined with CTX(-) non-O1/O139 isolates from Haiti and seroconverted O1 isolates from Brazil and Amazonia. One CTX(+) isolate was phylogenetically placed with the sixth pandemic classical clade and the V. cholerae O395 classical reference strain. Two CTX(+) El Tor isolates possessing intact Vibrio seventh pandemic island II (VSP-II) are related to hybrid El Tor isolates from Mozambique and Bangladesh. The third CTX(+) El Tor isolate contained West African-South American (WASA) recombination in VSP-II and showed relatedness to isolates from Peru and Brazil. Except for one isolate, all Mexican isolates lack SXT/R391 integrative conjugative elements (ICEs) and sensitivity to selected antibiotics, with one isolate resistant to streptomycin. No isolates were related to contemporary isolates from Asia, Africa, or Haiti, indicating phylogenetic diversity. IMPORTANCE: Sequencing of genomes of V. cholerae is critical if genetic changes occurring over time in the circulating population of an area of endemicity are to be understood. Although cholera outbreaks occurred rarely in Mexico prior to the 1990s, genetically diverse V. cholerae O1 strains were isolated between 1991 and 2008. Despite the lack of strong evidence, the notion that cholera was transmitted from Africa to Latin America has been proposed in the literature. In this study, we have applied whole-genome sequence analysis to a set of 124 V. cholerae strains, including six Mexican isolates, to determine their phylogenetic relationships. Phylogenetic analysis indicated the six V. cholerae O1 isolates belong to five phylogenetic clades: i.e., basal, nontoxigenic, classical, El Tor, and hybrid El Tor. Thus, the results of phylogenetic analysis, coupled with CTXϕ array and antibiotic susceptibility, do not support single-source transmission of cholera to Mexico from African countries. The association of indigenous populations of V. cholerae that has been observed in this study suggests it plays a significant role in the dynamics of cholera in Mexico.

Molecular tools in understanding the evolution of Vibrio cholerae.

Vibrio cholerae, the etiological agent of cholera, has been a scourge for centuries. Cholera remains a serious health threat for developing countries and has been responsible for millions of deaths globally over the past 200 years. Identification of V. cholerae has been accomplished using a variety of methods, ranging from phenotypic strategies to DNA based molecular typing and currently whole genomic approaches. This array of methods has been adopted in epidemiological investigations, either singly or in the aggregate, and more recently for evolutionary analyses of V. cholerae. Because the new technologies have been developed at an ever increasing pace, this review of the range of fingerprinting strategies, their relative advantages and limitations, and cholera case studies was undertaken. The task was challenging, considering the vast amount of the information available. To assist the study, key references representative of several areas of research are provided with the intent to provide readers with a comprehensive view of recent advances in the molecular epidemiology of V. cholerae. Suggestions for ways to obviate many of the current limitations of typing techniques are also provided. In summary, a comparative report has been prepared that includes the range from traditional typing to whole genomic strategies.

Occurrence in Mexico, 1998-2008, of Vibrio cholerae CTX+ El Tor carrying an additional truncated CTX prophage.

The seventh cholera pandemic caused by Vibrio cholerae O1 El Tor (ET) has been superseded in Asia and Africa by altered ET possessing the cholera toxin (CTX) gene of classical (CL) biotype. The CL biotype of V. cholerae was isolated, along with prototypic and altered ET, during the 1991 cholera epidemic in Mexico and subsequently remained endemic until 1997. Microbiological, molecular, and phylogenetic analyses of clinical and environmental V. cholerae isolated in Mexico between 1998 and 2008 revealed important genetic events favoring predominance of ET over CL and altered ET. V. cholerae altered ET was predominant after 1991 but not after 2000. V. cholerae strains isolated between 2001 and 2003 and a majority isolated in 2004 lacked CTX prophage (Φ) genes encoding CTX subunits A and B and repeat sequence transcriptional regulators of ET and CL biotypes: i.e., CTXΦ(-). Most CTXΦ(-) V. cholerae isolated in Mexico between 2001 and 2003 also lacked toxin coregulated pili tcpA whereas some carried either tcpA(ET) or a variant tcpA with noticeable sequence dissimilarity from tcpA(CL). The tcpA variants were not detected in 2005 after CTXΦ(+) ET became dominant. All clinical and environmental V. cholerae O1 strains isolated during 2005-2008 in Mexico were CTXΦ(+) ET, carrying an additional truncated CTXΦ instead of RS1 satellite phage. Despite V. cholerae CTXΦ(-) ET exhibiting heterogeneity in pulsed-field gel electrophoresis patterns, CTXΦ(+) ET isolated during 2004-2008 displayed homogeneity and clonal relationship with V. cholerae ET N16961 and V. cholerae ET isolated in Peru.