Isolation, Identification, and Antimicrobial Susceptibility Profiles of Gram-Negative Bacteria Isolated from Hemodialysis Units in Khartoum State, Sudan

Hospitals are places of healing, but they are also complex ecosystems teeming with invisible life. Among the countless microorganisms that inhabit these spaces, a specific group known as Gram-negative bacteria poses a persistent challenge. These are single-celled organisms with a distinct outer shell that makes them particularly tough to kill with standard treatments. In a hospital setting, they can cause serious illnesses, especially in patients whose immune systems are already weakened. One of the most vulnerable areas for these infections is the hemodialysis unit, where patients with kidney failure undergo a procedure to filter their blood. Because these treatments involve direct access to the bloodstream and rely on machines that circulate fluids, the environment must be exceptionally clean. If bacteria settle on the surfaces of the machines, the beds, or the surrounding equipment, they can hitch a ride into a patient's body, leading to severe complications. Understanding exactly which bacteria live in these rooms and whether common medicines can stop them is a matter of immediate safety for patients and staff alike.

In a recent study conducted in Khartoum State, Sudan, researchers set out to map this invisible landscape within local hemodialysis units. The team, working between June and October 2022, treated the dialysis wards as a living laboratory. They did not look for bacteria in the patients themselves, but rather in the environment where the treatment takes place. Using sterile swabs, similar to large cotton buds, they gently rubbed the surfaces of the dialysis machines, patient beds, benches, and desks. They collected sixty of these samples in total, carefully transporting them to a lab to see what would grow. The goal was simple yet critical: to identify the specific types of bacteria present and to test how well they responded to the antibiotics doctors would typically use to treat an infection.

When the samples were placed in nutrient-rich dishes to encourage growth, the results revealed a hidden world of microbial activity. Out of the sixty swabs taken, nineteen showed signs of bacterial life. These nineteen samples yielded a total of one hundred and fifty-seven distinct bacterial colonies, indicating that the environment was indeed a reservoir for these organisms. The most common resident found was a bacterium called Pseudomonas aeruginosa, which accounted for nearly forty-three percent of all the bacteria discovered. Following this were Acinetobacter baumannii and Serratia marcescens, which made up roughly nineteen and sixteen percent of the total, respectively. The researchers also found smaller numbers of other types, including Enterobacter, Citrobacter, Klebsiella, Escherichia coli, and Proteus. These findings confirmed that the dialysis rooms were not sterile; they harbored a diverse community of opportunistic pathogens capable of causing hospital-acquired infections.

The most significant part of the investigation, however, was not just identifying who was there, but determining how dangerous they might be in terms of drug resistance. The researchers tested every single bacterial isolate against a range of antibiotics, including powerful drugs like Meropenem, Gentamicin, and Amikacin. The results offered a surprising and reassuring picture. Despite the presence of these potentially harmful bacteria, the vast majority remained highly sensitive to the medications tested. In fact, the study found zero instances of multidrug-resistant strains, a type of superbug that is immune to multiple classes of antibiotics. Resistance was observed in only a tiny fraction of the cases: about seven percent of the bacteria did not respond to Gentamicin, seven percent to Meropenem, and a mere three percent to Amikacin. Even more strikingly, every single isolate was completely susceptible to Levofloxacin, Cefotaxime, Imipenem, and a combination drug known as SXT.

This study paints a clear portrait of the microbial environment in Sudanese hemodialysis units. While the rooms are undeniably contaminated with bacteria that could cause illness, the specific strains currently circulating have not yet developed the widespread resistance that makes modern medicine so difficult. The presence of these organisms serves as a reminder that vigilance is necessary, as the environment itself acts as a source of infection. Yet, the high susceptibility to available antibiotics suggests that if an infection were to occur, standard treatments would likely remain effective. The work underscores the importance of keeping these critical care areas clean, not just to prevent the spread of germs, but to ensure that the tools doctors rely on continue to work when they are needed most.