Acinetobacter baumannii has emerged as an increasing multidrug-resistant threat in hospitals and a common opportunistic nosocomial pathogen worldwide. However, molecular details of the pathogenesis and physiology of this bacterium largely remain to be elucidated. Here we identify and characterize the c-di-GMP signalling network and assess its role in biofilm formation and surface associated motility. Bioinformatic analysis revealed eleven candidate genes for c-di-GMP metabolizing proteins (GGDEF/EAL domain proteins) in the genome of A. baumannii strain 17978. Enzymatic activity of the encoded proteins was assessed by molecular cloning and expression in the model organisms Salmonella typhimurium and Vibrio cholerae. Ten of the eleven GGDEF/EAL proteins altered the rdar morphotype of S. typhimurium and the rugose morphotype of V. cholerae. The over expression of three GGDEF proteins exerted a pronounced effect on colony formation of A. baumannii on Congo Red agar plates. Distinct panels of GGDEF/EAL proteins were found to alter biofilm formation and surface associated motility of A. baumannii upon over expression. The GGDEF protein A1S_3296 appeared as a major diguanylate cyclase regulating macro-colony formation, biofilm formation and the surface associated motility. AIS_3296 promotes Csu pili mediated biofilm formation. We conclude that a functional c-di-GMP signalling network in A. baumannii regulates biofilm formation and surface associated motility of this increasingly important opportunistic bacterial pathogen.

Background: Acinetobacter baumanniiis a Gram-negative opportunistic pathogen with a notorious reputation of being resistant to antimicrobial agents. The capability ofA. baumanniito persist and disseminate between healthcare settings has raised a major concern worldwide.Methods: Our study investigated the antibiotic resistance features and molecular epidemiology of 52 clinical isolates ofA. baumanniicollected in Pakistan between 2013 and 2015. Antimicrobial susceptibility patterns were determined by the agar disc diffusion method. Comparative sequence analyses of theampCandbla_OXA-51-likealleles were used to assign the isolates into clusters. The whole genomes of 25 representative isolates were sequenced using the MiSeq Desktop Sequencer. Free online applications were used to determine the phylogeny of genomic sequences, retrieve the multilocus sequence types (ST), and detect acquired antimicrobial resistance genes.Results: Overall, the isolates were grouped into 7 clusters and 3 sporadic isolates. The largest cluster, Ab-Pak-cluster-1 (bla_OXA-66and ISAba1-ampC-19) included 24 isolates, belonged to ST2 and International clone (IC) II, and was distributed between two geographical far-off cities, Lahore and Peshawar. Ab-Pak-clusters-2 (bla_OXA-66, ISAba1-ampC-2), and -3 (bla_OXA-66, ISAba1-ampC-20) and the individual isolate Ab-Pak-Lah-01 (ISAba1-bla_OXA-66, ISAba1-ampC-2) were also assigned to ST2 and IC II. On the other hand, Ab-Pak-clusters-4 (bla_OXA-69,ampC-1), -5 (bla_OXA-69, ISAba1-ampC-78), and -6A (bla_OXA-371, ISAba1-ampC-3) belonged to ST1, while Ab-Pak-cluster-6B (bla_OXA-371, ISAba1-ampC-8) belonged to ST1106, with both ST1 and ST1106 being members of IC I. Five isolates belonged to Ab-Pak-cluster-7 (bla_OXA-65,ampC-43). This cluster corresponded to ST158, showed a well-delineated position on the genomic phylogenetic tree, and was equipped with several antimicrobial resistance genes includingbla_OXA-23andbla_GES-11.Conclusions: Our study detected the occurrence of 7 clusters ofA. baumanniiin Pakistan. Altogether, 6/7 of the clusters and 45/52 (86.5%) of the isolates belonged to IC I (n = 9) or II (n = 36), making Pakistan no exception to the global domination of these two clones. The onset of ST158 in Pakistan marked a geographical dispersal of this clone beyond the Middle East and brought up the need for a detailed characterization.

Urinary tract infections (UTIs) represent one of the most frequent bacterial infections worldwide, with Escherichia coli (E. coli) and Klebsiella pneumoniae (K. pneumoniae) as the predominant uropathogens. The emergence of extended-spectrum β-lactamase (ESBL)-producing Enterobacterales has severely limited treatment options, making regional surveillance crucial. This study aimed to determine the prevalence of uropathogens, assess antimicrobial resistance patterns, and evaluate the burden of ESBL-producing organisms among patients presenting with suspected UTIs in a tertiary care hospital in Riyadh. We conducted a retrospective analysis of 19,556 urine cultures from a tertiary care hospital in Riyadh, Saudi Arabia, between January and December 2024. Of these, 2629 (13.4%) cultures showed significant bacterial growth, predominantly in females (83.2%) and in the 16–30 year age group. E. coli accounted for 65.9% of isolates, followed by K. pneumoniae (16.8%). ESBL production was detected in 28.5% of E. coli and Klebsiella isolates. ESBL producers exhibited complete resistance to third-generation cephalosporins and β-lactam/β-lactamase inhibitor combinations, whereas carbapenems, aminoglycosides, and fosfomycin maintained high efficacy. Resistance to ciprofloxacin and co-trimoxazole was widespread in both ESBL and non-ESBL isolates. Additionally, vancomycin-resistant enterococci (7%), methicillin-resistant Staphylococcus aureus (2%), and carbapenem-resistant Enterobacterales (0.9%) were found. These findings highlight the escalating burden of ESBL-associated UTIs and underscore the urgent need for strengthened antimicrobial stewardship, continuous surveillance, and optimized empirical therapy to mitigate the impact of multidrug-resistant uropathogens in clinical practice.

Acinetobacter baumannii is one of the most common causes of nosocomial infections in developing countries. It has a better ability to get antimicrobial resistance due to plasticity in genome. The recent emergence of carbapenem-resistant A. baumannii isolates in several countries narrows down the spectrum of options to treat A. baumannii infections. The WHO has placed carbapenem-resistant A. baumannii on the top of priority organisms against which novel antibiotics are required. A systematic evaluation of carbapenem-resistant A. baumannii infections in three tertiary care hospitals in Pakistan is presented here. A total of 2270 positive culture samples were collected over a period of two years. Of which 1642 (72.33%) were respiratory tract specimens. A. baumannii was identified in 681 (41 %) cases. Of which 583 (85.5%) were carbapenem-resistant. Our findings suggest that the burden of carbapenem-resistant A. baumannii infections is alarmingly high in Pakistan.

The long history and extensive use of antibiotics have caused resistant bacterial pathogens to emerge, increasing mortality and morbidity. The current study was designed to see the prevalence of aerobic bacterial isolates with their antimicrobial resistance pattern from out- and inpatients requested for wound or pus culture. Retrospective study conducted at a tertiary care hospital in central Riyadh from January 2023 to December 2023. Samples were collected and inoculated onto the appropriate media following standard guidelines. Bacterial pathogens were identified by the Vitek2 compact system. Antimicrobial susceptibility was tested using the Kirby–Bauer disk diffusion method as well as by MIC determination through the Vitek2 compact. A total of 1186 subjects were included in the study with a bacterial isolation rate of 691 (58.3%). Out of these, 155 positive cultures had incomplete information or anaerobic or fungal growth and were excluded from the study. With a slight female predominance (54.9%), the majority of subjects (72.2%) were outpatients, and over half of the isolates (55.2%) were Gram-positive. The most common isolate was Staphylococcus spp. (44.4%), followed by E. coli (13.6%) and P. aeruginosa (12.9%). The highest resistance was reported against penicillin followed by fusidic acid against Gram-positive bacteria. Methicillin-resistant Staphylococcus aureus (MRSA) was detected in 40.5% of Staphylococcus aureus (S. aureus) isolates. Amikacin was the most susceptible antibiotic against all Gram-negative isolates. MDR Gram-negative bacteria accounted for 51.9% of wound infection isolates (95% CI: 45.95 to 58.33) while 6.3% (95% CI: 4.39 to 8.86) were XDR (nonsusceptibility to at least one agent in all but two or fewer antimicrobial categories). A high prevalence of bacterial isolates, with S. aureus as the predominant pathogen, showed high rates of multidrug resistance. This highlights the importance of monitoring antibiotic choices for prophylaxis and treatment in the study area.

Objectives: To evaluate the activity of Methylglyoxal against the blood culture isolates of Salmonella Typhi and various Gram negative rods and to compare the activity of Methylglyoxal against S. Typhi and other Gram negative rods. Methods: It was an experimental study conducted at the Department of Microbiology, University of Health Sciences (UHS), Lahore-Pakistan in collaboration with the Department of Microbiology, CMH Lahore, from July 2011 to June 2012. Recent blood culture isolates of S. Typhi and other Gram negative rods were collected from different hospitals of Lahore and kept stored at -80°C. As per the latest CLSI guidelines, morphological, biochemical and serological identification was carried out and antimicrobial susceptibility was tested. A multi-point inoculator was used to carry out agar dilution for determination of MICs of MGO. Results were determined after compilation of data using latest SPSS version. Results: MIC90 of MGO against the clinical isolates of S. Typhi was 0.20 mg/mL (2.8 mM) and against Gram negative rods it was 0.21 mg/mL (3.0 mM). The p-value of MICs of MGO against the isolates of S. Typhi was 0.023 when compared with Gram negative rods (p<0.05; statistically significant). Conclusion: MGO has a scientifically proven in vitro antimicrobial activity against blood culture isolates of S. Typhi and various Gram negative rods. doi: https://doi.org/10.12669/pjms.35.4.807 How to cite this:Afzal RK, Khalid F, Hannan A, Ahmed SA. Methylglyoxal: Antimicrobial activity against blood culture isolates of Salmonella Typhi and other Gram negative rods. Pak J Med Sci. 2019;35(4):1110-1114. doi: https://doi.org/10.12669/pjms.35.4.807 This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.