Prevalence of Multidrug Resistance among Salmonella enterica Serovar Typhimurium Isolated from Pig Faeces in Ashanti Region, Ghana

Introduction. Salmonella typhimurium is associated with outbreaks of food-borne nontyphoidal salmonellosis (NTS) worldwide with marked multidrug resistance. Objectives. This study aimed to determine the prevalence of antibiotic resistant Salmonella typhimurium in pigs in Ashanti Region, Ghana. Methods. Faeces from 10 pigs per pig farm were collected and mixed to obtain 108 multiply-composite faecal samples. Standard microbiology and biochemical procedures were used to isolate and identify an S. typhimurium isolate from the composite faecal sample of each farm. Antibiotic sensitivity test was carried out to determine the sensitivity of the isolates. Discussion. From the 108 multiply-composite faecal samples, 72 S. typhimurium isolates were obtained from 72 separate composite samples representing 72 different pig farms. Of the 72 faecal isolates, 32 (52.8%) were resistant to at least one antibiotic. Twenty-seven isolates (71.1%) were resistant to amoxicillin and streptomycin. Resistance to tetracycline, doxycycline, and ciprofloxacin was found in 17 (44.7%), 15 (39.5%), and 8 (21.1%) isolates, respectively. Resistance to norfloxacin, sulphamethoxazole-trimethoprim, and gentamicin were expressed in 3 (7.9%), 3 (7.9%), and 0 (0.0%) isolates, respectively. Conclusion. Multiple drug resistance is common in S. typhimurium isolates, many of which could belong to the same clone, from pigs in Ashanti Region, Ghana.

Comparative Evaluation of the Inhibitory Effect of Some Essential Oils with Antibiotics against Pseudomonas aeruginosa

Gas chromatography/mass spectroscopy analysis was performed to identify the chemical components of three extracted essential oils including thyme, marjoram, and sage. The antibacterial activity of the extracted essential oils against Pseudomonas aeruginosa (ATCC 9027) was investigated using disc diffusion assay, either alone or in combination with standard antibiotics (piperacillin, cefepime, meropenem, gentamicin, and norfloxacin). Results showed that the studied oils exhibited a variety of activities against the tested bacterium. Thyme oil was the most active followed by marjoram oil, whereas sage displayed no activity towards the tested organism. Thyme oil enhanced the antibacterial activity of cell wall targeting antibiotics (piperacillin, cefepime, and meropenem) by more than twofold. Marjoram oil potentiated the activity of all the tested antibiotics except norfloxacin. Sage, despite its inactivity against pseudomonas, synergistically enhanced the activity of piperacillin, meropenem, and gentamicin. Thyme essential oil, containing thymol as a major component (33.6%), exhibited higher activity alone or in combination with antibiotics than marjoram which contained alcoholic terpenes or sage essential oil that contained 1,8-cineole as its major component (29%). The investigated oils, as natural bioactive agents, may be used to enhance the activity of antibiotics towards pseudomonas.

Protolichesterinic Acid: A Prominent Broad Spectrum Antimicrobial Compound from the Lichen Usnea albopunctata

The aim of this study is to investigate the antimicrobial compounds present in the lichen Usnea albopunctata. Ethyl acetate extract was purified by silica gel column chromatography to obtain a major compound and the chemical structure was characterized by 1H-NMR, 13C-NMR, DEPT, 1H-1H COSY, HMQC, HMBC, UV, and HR-MS spectroscopic methods as protolichesterinic acid. The antimicrobial activity was estimated by determination of the minimal inhibitory concentration by the broth microdilution method and agar disc diffusion method against thirteen human pathogenic bacterial and four fungal strains. Protolichesterinic acid recorded significant broad spectrum antimicrobial property. The best antibacterial activity was recorded against K. pneumonia (0.25 μg/mL) and V. cholerae (0.5 μg/mL). Significant antifungal activity was recorded against T. rubrum (0.12 μg/mL), which is significantly better than the standard antifungal agent. Protolichesterinic acid is reported for the first time from Usnea albopunctata. Antifungal activity of protolichesterinic acid against medically important fungi is also reported for the first time. Thus the results of the present study suggest that protolichesterinic acid has significant antimicrobial activities and has the strong potential to be developed as an antimicrobial drug after further clinical evaluation.

Effects of Chlorophyll-Derived Efflux Pump Inhibitor Pheophorbide a and Pyropheophorbide a on Growth and Macrolide Antibiotic Resistance of Indicator and Anaerobic Swine Manure Bacteria

Natural plant compounds, such as the chlorophyll a catabolites pheophorbide a (php) and pyropheophorbide a (pyp), are potentially active in the gastrointestinal tracts and manure of livestock as antimicrobial resistance-modifying agents through inhibition of bacterial efflux pumps. To investigate whether php, a known efflux pump inhibitor, and pyp influence bacterial resistance, we determined their long-term effects on the MICs of erythromycin for reference strains of clinically relevant indicator bacteria with macrolide or multidrug resistance efflux pumps. Pyp reduced the final MIC endpoint for Staphylococcus (S.) aureus and Escherichia (E.) coli by up to 1536 and 1024 μg erythromycin mL−1 or 1.4- and 1.2-fold, respectively. Estimation of growth parameters of S. aureus revealed that pyp exerted an intrinsic inhibitory effect under anaerobic conditions and was synergistically active, thereby potentiating the effect of erythromycin and partially reversing high-level erythromycin resistance. Anaerobe colony counts of total and erythromycin-resistant bacteria from stored swine manure samples tended to be lower in the presence of pyp. Tylosin, php, and pyp were not detectable by HPLC in the manure or medium. This is the first study showing that pyp affects growth and the level of sensitivity to erythromycin of S. aureus, E. coli, and anaerobic manure bacteria.

The Occurrence of blaCTX-M, blaSHV, and blaTEM Genes in Extended-Spectrum β-Lactamase-Positive Strains of Klebsiella pneumoniae, Escherichia coli, and Proteus mirabilis in Poland

Bacteria belonging to the Enterobacteriaceae family that produce extended-spectrum β-lactamase (ESBL) enzymes are important pathogens of infections. Increasing numbers of ESBL-producing bacterial strains exhibiting multidrug resistance have been observed. The aim of the study was to evaluate the prevalence of blaCTX-M, blaSHV, and blaTEM genes among ESBL-producing Klebsiella pneumoniae, Escherichia coli, and Proteus mirabilis strains and to examine susceptibility to antibiotics of tested strains. In our study, thirty-six of the tested strains exhibited blaCTX-M genes (blaCTX-M-15, blaCTX-M-3, blaCTX-M-91, and blaCTX-M-89). Moreover, twelve ESBL-positive strains harbored blaSHV genes (blaSHV-18, blaSHV-7, blaSHV-2, and blaSHV-5), and the presence of a blaTEM gene (blaTEM-1) in twenty-five ESBL-positive strains was revealed. Among K. pneumoniae the multiple ESBL genotype composed of blaCTX-M-15, blaCTX-M-3, blaSHV-18, blaSHV-7, blaSHV-2, and blaSHV-5 genes encoding particular ESBL variants was observed. Analysis of bacterial susceptibility to antibiotics revealed that, among β-lactam antibiotics, the most effective against E. coli strains was meropenem (100%), whereas K. pneumoniae were completely susceptible to ertapenem and meropenem (100%), and P. mirabilis strains were susceptible to ertapenem (91.7%). Moreover, among non-β-lactam antibiotics, gentamicin showed the highest activity to E. coli (91.7%) and ciprofloxacin the highest to K. pneumoniae (83.3%). P. mirabilis revealed the highest susceptibility to amikacin (66.7%).

Risk Factor Analysis and Microbial Etiology of Surgical Site Infections following Lower Segment Caesarean Section

Background. Lower segment caesarean section (LSCS) is a common mode of delivery now and surgical site infection is the second most common infectious complication in these patients. This study was planned with this background to have a comprehensive approach to SSI following LSCS. Methods. 500 consecutive patients undergoing LSCS, irrespective of indication, were studied. A questionnaire was developed to assess the risk factors associated with development of SSI. All patients were followed up from day one of surgery till discharge and then up till the postoperative day 30 after discharge. Results. SSI was identified in 121 (24.2%) out of 500 patients. In all age groups, Gram-negative bacilli were the commonest finding. The commonest isolate was Acinetobacter species (32.03%) followed by Staphylococcus aureus and coagulase negative Staphylococcus (21.09%). 23.8% of Staphylococcus aureus strains were MRSA. By multivariate logistic regression premature rupture of membrane (PROM), antibiotics given earlier than 2 hours and increased duration of stay in the hospital were found to be significant. Conclusions. A proper assessment of risk factors that predispose to SSI and their modification may help in reduction of SSI rates. Also, frequent antimicrobial audit and qualitative research could give an insight into the current antibiotic prescription practices and the factors affecting these practices.