Antibiotic resistance pattern of Pseudomonas spp. from patients in a tertiary hospital in South-West Nigeria

Update on Urinary Tract Infection Antibiotic Resistance-A Retrospective Study in Females in Conjunction with Clinical Data

Urinary tract infections (UTIs) represent a frequent pathology among the female population that has become more and more difficult to treat in the past decade, considering the increase in antibiotic resistance-a serious global public health problem. A cross-sectional retrospective study was conducted for six months to report an update regarding the rates of resistance and susceptibility of uropathogens necessary for optimal treatment. A total of 5487 patients were screened, of which 524 (9.54%) were female patients who met the criteria for inclusion in the study. Escherichia coli was the most common pathogen, representing 290 cases (55.34%), followed by Enterococcus spp. 82 (15.64%). Escherichia coli presented the highest resistance to amoxicillin-clavulanic acid (R = 33.1%), followed by trimethoprim-sulfamethoxazole (R = 32.41%) and levofloxacin (R = 32.06%). The highest sensitivity rates were observed for fosfomycin (S = 96.55%), followed by imipenem (S = 93.1%). Enterococcus spp. showed the highest resistance to levofloxacin (R = 50.0%), followed by penicillin (R = 39.02%). The highest sensitivity was observed for fosfomycin (S = 90.24%), linezolid (S = 89.02%), and nitrofurantoin (S = 86.58%). The second most frequent Gram-negative uropathogen was represented by Klebsiella spp., which had the highest resistance to amoxicillin-clavulanic acid (R = 35.89%), followed by levofloxacin (R = 25.64) and trimethoprim-suflamethoxazole (R = 24.35%). The most frequently associated pathology was an episode of UTI in the previous year, followed by diabetes and chronic kidney disease. Antibiotic resistance is a serious problem for all clinicians who treat UTIs. An up-to-date knowledge of antibiotic resistance rates is a major necessity to stop its evolution. Overall, the highest resistance rates were observed for aminopenicillins, fluoroquinolones, and trimethoprim-sulfamethoxazole. The best susceptibility rates were observed for fosfomycin, nitrofurantoin, and carbapenems. Our report aims to guide clinicians whenever they are forced to prescribe antibiotics empirically.

Showing the limitations of available phenotypic assays to detect Burkholderia pseudomallei from clinical specimens in Nigeria

The genus Burkholderia comprises Gram-negative bacteria that are metabolically complex and versatile, often thriving in hostile settings. Burkholderia pseudomallei , the causative agent of melioidosis, is a prominent member of the genus and a clinical pathogen in tropical and sub-tropical regions. This pathogen is well known for its multidrug resistance and possible bioweapon potential. There is currently no report of the pathogen from clinical specimens in Nigeria, which might be due to misdiagnosis with phenotypic assays. This study aims to explore the accuracy of the use of phenotypic assays to diagnose B. pseudomallei in Nigeria. Two hundred and seventeen clinical samples and 28 Gram-negative clinical isolates were collected and analysed using Ashdown's selective agar and monoclonal antibody-based latex agglutination. Species-level identification was achieved using the analytical profile index (API) 20NE system. The susceptibility of the isolates to nine different antimicrobial agents was determined using the disc diffusion method. A total of seventy-four culture-positive isolates were obtained using Ashdown's selective agar. Twenty-two of these isolates were believed to be B. pseudomallei through the monoclonal antibody-based latex agglutination test and the API 20NE system subsequently identified 14 isolates as Burkholderia . The predominant Burkholderia species was B. cepacia with an isolation rate of 30.8 % (8/26). No isolate was distinctively identified as B. pseudomallei but five isolates were strongly suspected to be B. pseudomallei with similarity indices ranging from 81.9-91.3 %. Other bacterial species with definitive identity include Aeromonas sp., Sphingomonas sp. and Pseudomonas aeruginosa . The antibiotic susceptibility results revealed an overall resistance to amoxicillin-clavullanic acid of 71.4 %, to cefepime of 33.3 %, to trimethoprim-sulfamethoxazole of 38.1 %, to piperacillin-tazobactam of 33.3 %, to imipenem of 66.7 %, to doxycycline of 57.1% and to ceftazidime of 66.7 %. The highest intermediate resistance was observed for cefepime and piperacillin-tazobactam with a value of 66.7 % each, while there was no intermediate resistance for gentamicin, colistin and imipenem. Our findings, therefore, show that phenotypic assays alone are not sufficient in the diagnosis of melioidosis. Additionally, they provide robust support for present and future decisions to expand diagnostic capability for melioidosis beyond phenotypic assays in low-resource settings.

The Art of War with Pseudomonas aeruginosa: Targeting Mex Efflux Pumps Directly to Strategically Enhance Antipseudomonal Drug Efficacy

Pseudomonas aeruginosa (P. aeruginosa) poses a grave clinical challenge due to its multidrug resistance (MDR) phenotype, leading to severe and life-threatening infections. This bacterium exhibits both intrinsic resistance to various antipseudomonal agents and acquired resistance against nearly all available antibiotics, contributing to its MDR phenotype. Multiple mechanisms, including enzyme production, loss of outer membrane proteins, target mutations, and multidrug efflux systems, contribute to its antimicrobial resistance. The clinical importance of addressing MDR in P. aeruginosa is paramount, and one pivotal determinant is the resistance-nodulation-division (RND) family of drug/proton antiporters, notably the Mex efflux pumps. These pumps function as crucial defenders, reinforcing the emergence of extensively drug-resistant (XDR) and pandrug-resistant (PDR) strains, which underscores the urgency of the situation. Overcoming this challenge necessitates the exploration and development of potent efflux pump inhibitors (EPIs) to restore the efficacy of existing antipseudomonal drugs. By effectively countering or bypassing efflux activities, EPIs hold tremendous potential for restoring the antibacterial activity against P. aeruginosa and other Gram-negative pathogens. This review focuses on concurrent MDR, highlighting the clinical significance of efflux pumps, particularly the Mex efflux pumps, in driving MDR. It explores promising EPIs and delves into the structural characteristics of the MexB subunit and its substrate binding sites.

Study of Antimicrobial Resistance, Biofilm Formation, and Motility of Pseudomonas aeruginosa Derived from Urine Samples

Pseudomonas aeruginosa causes urinary tract infections associated with catheters by forming biofilms on the surface of indwelling catheters. Therefore, controlling the spread of the bacteria is crucial to preventing its transmission in hospitals and the environment. Thus, our objective was to determine the antibiotic susceptibility profiles of twenty-five P. aeruginosa isolates from UTIs at the Medical Center of Trás-os-Montes and Alto Douro (CHTMAD). Biofilm formation and motility are also virulence factors studied in this work. Out of the twenty-five P. aeruginosa isolates, 16% exhibited multidrug resistance, being resistant to at least three classes of antibiotics. However, the isolates showed a high prevalence of susceptibility to amikacin and tobramycin. Resistance to carbapenem antibiotics, essential for treating infections when other antibiotics fail, was low in this study, Notably, 92% of the isolates demonstrated intermediate sensitivity to ciprofloxacin, raising concerns about its efficacy in controlling the disease. Genotypic analysis revealed the presence of various β-lactamase genes, with class B metallo-β-lactamases (MBLs) being the most common. The bla_NDM, bla_SPM, and bla_VIM-VIM2 genes were detected in 16%, 60%, and 12% of the strains, respectively. The presence of these genes highlights the emerging threat of MBL-mediated resistance. Additionally, virulence gene analysis showed varying prevalence rates among the strains. The exoU gene, associated with cytotoxicity, was found in only one isolate, while other genes such as exoS, exoA, exoY, and exoT had a high prevalence. The toxA and lasB genes were present in all isolates, whereas the lasA gene was absent. The presence of various virulence genes suggests the potential of these strains to cause severe infections. This pathogen demonstrated proficiency in producing biofilms, as 92% of the isolates were found to be capable of doing so. Currently, antibiotic resistance is one of the most serious public health problems, as options become inadequate with the continued emergence and spread of multidrug-resistant strains, combined with the high rate of biofilm production and the ease of dissemination. In conclusion, this study provides insights into the antibiotic resistance and virulence profiles of P. aeruginosa strains isolated from human urine infections, highlighting the need for continued surveillance and appropriate therapeutic approaches.

Presence of Burkholderia pseudomallei in Soil, Nigeria, 2019

Melioidosis, caused by the soil-dwelling bacterium Burkholderia pseudomallei, is predicted to be endemic in Nigeria but is only occasionally reported. This report documents the systematic identification of the presence of B. pseudomallei and B. thailandensis in the soil across multiple states in Nigeria.