Investigation of Multidrug-Resistant Klebsiella pneumoniae and Acinetobacter baumannii Isolated from Inpatients at Al-Nasiriyah Teaching Hospital

Abstract

This study aimed to determine the prevalence, phenotypic characteristics, molecular identification, and antibiotic resistance pattern of both of A. baumannii and K. pneumoniae in inpatients at Al-Nasiriyah Teaching Hospital, Iraq. A total of 150 clinical specimens were obtained and processed for A. baumannii and K. pneumoniae isolation using typical microbiological, PCR and DNA sequencing techniques. The antimicrobial susceptibility testing was conducted by using VITEK-2. The results revealed a 23% (35/150) prevalence of A. baumannii, and the same ratio for K. pneumoniae was identified and diagnosed; however, the remaining gram-negative isolates represented 54%. PCR confirmed these isolates as A. baumannii and K. pneumoniae using specific primers. The antibiogram profile revealed high susceptibility to tigecycline (94.3%) by all of our tested isolates. There was a high prevalence of multidrug resistance among both species, with A. baumannii demonstrating complete resistance to several key antibiotics. Sample-type-specific patterns were also identified. Both bacterial species can be classified as MDR. The significant burden of MDR and XDR profiles among A. baumannii and K. pneumoniae in these inpatient samples emphasizes the need for optimized experimental therapy and rigorous administration in Thi-Qar.

Keywords:

MDR, A. baumannii, K. pneumoniae, antibiotic resistance, VITEK

References

Centers for Disease Control and Prevention. (2025). Antimicrobial resistance threats in the United States, 2021–2022. https://www.cdc.gov/antimicrobial-resistance/data-research/threats/update-2022.html.

Magiorakos, A. P., Srinivasan, A., Carey, R. B., Carmeli, Y., Falagas, M. E., Giske, C. G., et al. (2012). Multidrug-resistant, extensively drug-resistant and pandrug-resistant bacteria: An international expert proposal for interim standard definitions for acquired resistance. Clinical Microbiology and Infection, 18(3), 268–281. https://doi.org/10.1111/j.1469-0691.2011.03570.x.

Antimicrobial Resistance Collaborators. (2022). Global burden of bacterial antimicrobial resistance in 2019: A systematic analysis. The Lancet, 399(10325), 629–655. https://doi.org/10.1016/S0140-6736(21)02724-0.

Peleg, A. Y., Seifert, H., & Paterson, D. L. (2008). Acinetobacter baumannii: Emergence of a successful pathogen. Clinical Microbiology Reviews, 21(3), 538–582. https://doi.org/10.1128/CMR.00058-07.

Logan, L. K., & Weinstein, R. A. (2017). The epidemiology of carbapenem-resistant Enterobacteriaceae: The impact and evolution of a global menace. The Journal of Infectious Diseases, 215(Suppl. 1), S28–S36. https://doi.org/10.1093/infdis/jiw282.

World Health Organization. (2024, May 17). WHO updates list of drug-resistant bacteria most threatening to human health (WHO Bacterial Priority Pathogens List 2024). https://www.who.int/news/item/17-05-2024-who-updates-list-of-drug-resistant-bacteria-most-threatening-to-human-health.

World Health Organization. (2024). Disease Outbreak News: Global situation update on hypervirulent Klebsiella pneumoniae. https://www.who.int/emergencies/disease-outbreak-news.

Das, M. (2024). Global update on hypervirulent Klebsiella pneumoniae. The Lancet Infectious Diseases, 24(10), e621. https://doi.org/10.1016/S1473-3099(24)00610-8.

Azizi, O., Shahcheraghi, F., Salimizand, H., et al. (2020). Molecular analysis and genetic diversity of carbapenem-resistant Acinetobacter baumannii isolates in Iran. Antimicrobial Resistance & Infection Control, 9, 142. https://doi.org/10.1186/s13756-020-00842-1.

Zowawi, H. M., Balkhy, H. H., Walsh, T. R., & Paterson, D. L. (2013). β-lactamase production in key Gram-negative pathogen isolates from the Gulf Cooperation Council states: A literature review. International Journal of Antimicrobial Agents, 42(4), 360–364. https://doi.org/10.1016/j.ijantimicag.2013.06.001.

Abdul-Wahab, D. H., Al-Amara, S. S. M., & Alboslemy, T. A. (2024). Distribution of TEM and SHV genes in ESBL-producing Klebsiella pneumoniae strains isolated from various clinical samples in Al-Basrah Province, Iraq. South Eastern European Journal of Public Health, 2024, 212–218. https://doi.org/10.70135/seejph.vi.976.

Mozan, I. M., & Al-Amara, S. S. M. (2023). Frequencies of New Delhi metallo-β-lactamase (NDM) in Klebsiella pneumoniae isolates from clinical samples in Al-Basrah Governorate, Iraq. Scientific Journal of Medical Research, 7(27), 15–18. https://doi.org/10.37623/sjomr.v07i27.03.

Al-Badr, H. J., Abdulridha, K., Hussain, R. H., & Abid, N. R. (2023). Hospital environment reservoirs for carbapenem-resistant Gram-negative bacilli in Basra, Iraq. Iraqi National Journal of Medicine, 5(1).

Habash, R. T., & Jabir, D. M. (2025). Molecular detection and antibiotic sensitivity of Acinetobacter baumannii isolated from clinical samples in Thi-Qar—Southern Iraq. Thi-Qar Medical Journal, 29(1), 57–63. https://doi.org/10.32792/jmed.2025.29.8.

Tsioutis, C., Kritsotakis, E. I., Karageorgos, S. A., Stratakou, S., Psarologakis, C., Kokkini, S., & Gikas, A. (2016). Clinical epidemiology, treatment and prognostic factors of extensively drug-resistant Acinetobacter baumannii ventilator-associated pneumonia in critically ill patients. International Journal of Antimicrobial Agents, 48(5), 492–497. https://doi.org/10.1016/j.ijantimicag.2016.07.007.

Nation, R. L., Li, J., Cars, O., Couet, W., Dudley, M. N., Kaye, K. S., et al. (2015). Framework for optimization of the clinical use of colistin and polymyxin B: The Prato polymyxin consensus. The Lancet Infectious Diseases, 15(2), 225–234. https://doi.org/10.1016/S1473-3099(14)70850-3.

World Health Organization. (2024). Global Antimicrobial Resistance Surveillance System (GLASS) report: 2024 update. https://www.who.int/activities/global-antimicrobial-resistance-surveillance-system.

Chimana, H. M., Kwenda, G., Samutela, M. T., Yankonde, B., Mukena, N., Nakazwe, R., et al. (2025). Antimicrobial resistance of clinical and environmental Klebsiella pneumoniae isolates in selected areas of Lusaka, Zambia. African Journal of Microbiology Research, 19(5), 72–82. https://doi.org/10.5897/AJMR2024.9781.

Mesapogu, S., Jillepalli, C. M., & Arora, D. K. (2013). Microbial DNA extraction, purification, and quantitation. In Analyzing microbes (pp. 1–17). Springer. https://doi.org/10.1007/978-3-642-34410-7_1.

Wilson, K. (2001). Preparation of genomic DNA from bacteria. In Current protocols in molecular biology.

Lal, U. P., Ambhore, N., Raut, S., Mantri, R., Malak, N., & Sharma, P. (2024). Identification of inducible clindamycin resistance in Staphylococcus aureus using automated Vitek-2 Compact System and D test. Journal of Medical Sciences, 10(2), 136.

Balouiri, M., Sadiki, M., & Ibnsouda, S. K. (2016). Methods for in vitro evaluating antimicrobial activity: A review. Journal of Pharmaceutical Analysis, 6(2), 71–79. https://doi.org/10.1016/j.jpha.2015.11.005.

Lee, M., & Chung, H. S. (2015). Different antimicrobial susceptibility testing methods to detect ertapenem resistance in Enterobacteriaceae: VITEK2, MicroScan, Etest, disk diffusion, and broth microdilution. Journal of Microbiological Methods, 112, 87–91. https://doi.org/10.1016/j.mimet.2015.03.014.

Podschun, R., & Ullmann, U. (1998). Klebsiella spp. as nosocomial pathogens: Epidemiology, taxonomy, typing methods, and pathogenicity factors. Clinical Microbiology Reviews, 11(4), 589–603. https://doi.org/10.1128/CMR.11.4.589.

Yang, F., Liu, F. Y., & Zhong, Y. M. (2024). Comparative genomics revealing the genomic characteristics of Klebsiella variicola clinical isolates in China. Tropical Medicine and Infectious Disease, 9(8), 180. https://doi.org/10.3390/tropicalmed9080180.

Liu, J., Spencer, N., Utter, D. R., Grossman, A. S., Lei, L., Dos Santos, N. C., et al. (2024). Persistent enrichment of multidrug-resistant Klebsiella in oral and nasal communities during long-term starvation. Microbiome, 12(1), 132. https://doi.org/10.1186/s40168-024-01854-5.

Kadim, B. M. (2024). Distribution of antibacterial resistance among pathogenic bacterial isolates from patients in Al-Shatrah General Hospital. UTJagr, 13(2), 679–690. https://doi.org/10.54174/6ed6q702.