Department of Pediatrics, Division of Infectious Diseases, Baylor College of Medicine and Texas Children's Hospital, Houston, Texas, USA.
Microbiol Spectr. 2024 Oct 3;12(10):e0086924. doi: 10.1128/spectrum.00869-24. Epub 2024 Sep 9.
Shortly after its introduction into clinical practice, isolates gained resistance to penicillin via the acquisition of β-lactamases. A number of centers have recently described an increase in the proportion of invasive methicillin-susceptible (MSSA), which are also susceptible to penicillin (PSSA). Little data are available regarding the prevalence or impact of PSSA in skin and soft tissue infections (SSTI). Community-acquired MSSA SSTI isolates were obtained through a surveillance study at Texas Children's Hospital from January 2017 to December 2021. A total of 200 random isolates underwent PCR for β-lactamase; -negative isolates then underwent penicillin susceptibility testing using macrobroth dilution. Isolates which were negative and had a penicillin MIC ≤0.125 µg/mL were regarded as PSSA with the remainder regarded as penicillin-resistant MSSA (PR-MSSA). All PSSA underwent multilocus sequence typing. Medical records were reviewed. The median age of subjects was 4.2 years (IQR: 1.6-10.5). PSSA accounted for 9% of isolates during the study period. PSSA and PR-MSSA cases were similar with respect to age, demographics, and rates of prior antibiotic exposure. PSSA isolates less often had vancomycin MIC ≥1.5 µg/mL. Furthermore, 39% of PSSA were variants of sequence type 1. In multivariable analyses, penicillin susceptibility was independently associated with both hospital admission and surgical intervention. PSSA account for a small but significant proportion of MSSA SSTI in children. Clinically distinguishing patients with PSSA and PR-MSSA SSTI is challenging. However, PSSA SSTI were independently associated with higher rates of hospital admission as well as the need for surgical intervention suggesting a significant clinical impact.IMPORTANCEThe vast majority of in the US are penicillin resistant with most clinical labs no longer reporting penicillin susceptibility for this organism. A number of centers, however, have reported increasing penicillin susceptibility among invasive infections. Skin and soft tissue infections (SSTI) are far more common than invasive infections, yet the frequency and impact of penicillin-susceptible (PSSA) in this population are uncertain. Through active surveillance at a children's hospital, we found that 9% of methicillin-susceptible SSTI isolates were PSSA. PSSA were independently associated with hospital admission for the management of SSTI as well as the need for debridement in the operating room. Given that most SSTI are managed in the outpatient setting, these findings suggest a clinical impact of this phenotype and the need for a reassessment of the value in susceptibility testing and potentially even treatment with penicillin.
在将其引入临床实践后不久， 株通过获得β-内酰胺酶获得了对青霉素的耐药性。最近，许多中心都描述了侵袭性耐甲氧西林敏感金黄色葡萄球菌（MSSA）的比例增加，这些细菌也对青霉素敏感（PSSA）。关于皮肤和软组织感染（SSTI）中 PSSA 的流行率或影响，几乎没有数据。社区获得性 MSSA SSTI 分离株通过德克萨斯儿童医院 2017 年 1 月至 2021 年 12 月的监测研究获得。共有 200 个随机分离株进行了β-内酰胺酶的 PCR；β-阴性分离株随后使用大肉汤稀释法进行青霉素药敏试验。青霉素 MIC ≤0.125μg/ml 的阴性和阴性分离株被视为 PSSA，其余被视为青霉素耐药性 MSSA（PR-MSSA）。所有 PSSA 均进行多位点序列分型。回顾病历。受试者的中位年龄为 4.2 岁（IQR：1.6-10.5）。在研究期间，PSSA 占分离株的 9%。PSSA 和 PR-MSSA 病例在年龄、人口统计学和抗生素暴露率方面相似。PSSA 分离株万古霉素 MIC≥1.5μg/ml 的情况较少。此外，39%的 PSSA 是序列型 1 的变体。多变量分析显示，青霉素敏感性与住院和手术干预独立相关。PSSA 占儿童 MSSA SSTI 的一小部分，但比例显著。临床上区分 PSSA 和 PR-MSSA SSTI 患者具有挑战性。然而，PSSA SSTI 与更高的住院率和手术干预的需要独立相关，表明其具有显著的临床影响。
美国绝大多数 对青霉素耐药，大多数临床实验室不再报告这种生物体的青霉素敏感性。然而，一些中心报告称，侵袭性 感染的青霉素敏感性增加。皮肤和软组织感染（SSTI）远比侵袭性感染更为常见，但在该人群中，青霉素敏感 （PSSA）的频率和影响尚不确定。通过在儿童医院的主动监测，我们发现 9%的耐甲氧西林敏感的 SSTI 分离株是 PSSA。PSSA 与 SSTI 的住院管理以及手术室清创的需要独立相关。鉴于大多数 SSTI 都是在门诊环境中治疗的，这些发现表明这种表型具有临床影响，需要重新评估药敏试验的价值，甚至可能需要用青霉素进行治疗。
