In an ordinary scenario at an intensive care unit (ICU), a highly unusual result threw everyone off guard. A strain of Pseudomonas aeruginosa, commonplace in hospital-acquired infections identified in moist areas was discovered with a peculiar twist. It carried the New Delhi metallo-β-lactamase or NDM-1 gene, an enzyme notorious for nullifying the effects of potent antibiotics like carbapenems. This marked the first encounter of the NDM-1 producing strain at UCLA Health, a significant anomaly since the patient held no travel history, and NDM-1 prevalence outside Asia, Europe, and the Middle East is sparse.
Over the next year and a half, the same rare strain was identified in seven other patients, raising alarms since the detections didn’t follow standard outbreak patterns, seemingly disparate in time-space dimensions. Eventually, after a detailed analysis, the multidisciplinary team consisting of infection prevention and microbiology professionals traced back the bacterial strain to an isolated ICU sink, a silent forebearer of the lurking pathogens.
The hospital’s hitherto unprecedented finding was later detailed in a study published in the American Journal of Infection Control. The roots of the investigation sprung when Dr. Shangxin Yang’s team detected the NDM-1 strain. Their dilemmas led them to contact Dr. Dan Uslan, Chief Infection Prevention Officer at UCLA Health, whose team subsequently kicked off a comprehensive inquiry to trace the origins of the NDM-1 gene’s intriguing presence.
This investigation encompassed an evaluation of shared equipment, general nursing staff, respiratory therapy protocols, and environmental surfaces. The trail, however, went cold until more cases started to surface. These did not follow an intuitive outbreak pattern, making it even harder for the team to find the root cause.
The UCLA team resorted to a cutting-edge technique known as whole-genome sequencing to determine if the various cases were interlinked. This highly specialized method deciphers the entire DNA blueprint of bacteria, enabling scientists to detect and trace the origins of drug-resistance mutations while also potentially identifying a common infection source.
Through whole-genome sequencing, the UCLA team discovered root commonalities in seven out of eight cases and two sink isolates. Interestingly, only one patient who had prior medical aid in Iran carried a variant strain. The breakthrough came during the third round of exhaustive environment inspections, where an ICU sink drain presented with the same Pseudomonas aeruginosa bacteria and the strikingly similar genetic fingerprint found in the patients.
The big question remained as to how this NDM-1 strain managed to survive in the sink’s plumbing for so long. Pseudomonas bacteria are proficient at creating biofilms which are layers that affix to plumbing and guard the bacteria from standard disinfectants, as explained by Dr. Uslan. These biofilms are notoriously resistant to cleaning and disinfection, making eradication quite challenging.
To halt the NDM-1 spread, a targeted intervention was introduced, which included weekly treatments with Virasept™, a verified EPA-registered disinfectant capable of breaking down bacterial biofilms. Concurrently, physical modifications were also made to the sink’s plumbing; the faucet angles were adjusted to curb water from directly hitting the drain and aerosolizing droplets. Staff was also educated on maintaining all patient care supplies outside the sink’s splash zone to prevent cross-contamination.
Upon implementation of these corrective measures, no further infections were reported, thereby attesting to the effectiveness of this multi-pronged approach. This incident and subsequent study underscore several critical takeaways for healthcare providers and hospital systems at large.
The perfect resolution of this case would have been impossible without the synergistic interplay of infection prevention, microbiology, and facilities, according to Dr. Uslan. This was an impeccable example of a well-coordinated effort by experts in diverse fields, combining their knowledge to overcome a hidden threat and ensure continued patient safety.
Source: https://www.uclahealth.org/news/article/these-techniques-stopped-outbreak-antibiotic-resistant