LITERATURE UPDATE
Staining for microorganisms: a selection of current research interest
While genomic methods are gaining importance across pathology, especially in infection sciences and tissue sciences, the application of routine staining methods continues to complement 21st-century technology. The following papers include the use of Christian Gram’s eponymous method or that named after two German doctors, the bacteriologist Franz Ziehl and pathologist Friedrich Neelsen.
Intraoperative Gram staining of bile for the prevention of infectious complications in pancreaticoduodenectomy Hinojosa Arco LC, Roldán de la Rua JF, Carranque Chaves GÁ, Mora Navas L, de Luna Díaz R, Suárez Muñoz MÁ. Cir Esp (Engl Ed) 2021 Jun 18: S0009- 739X(21)00181-0. doi: 10.1016/j. ciresp.2021.05.004. Online ahead of print.
Infectious complications play a prominent role in pancreaticoduodenectomy. Their incidence increases in cases with preoperative biliary drainage (PBD), due to the higher risk of bacterobilia. The aim of this study is to evaluate an antibiotherapy protocol based on intraoperative Gram staining of bile and its impact on postoperative infectious complications. A retrospective study analysed the incidence of infectious complications between two groups of 25 consecutive patients undergoing pancreaticoduodenectomy. In group 1, cefazolin prophylaxis was administered to patients without PBD. In cases with PBD a five-day antibiotherapy with piperacillin- tazobactam was administered. In group 2,
intraoperative Gram staining of bile was routinely performed. If no microorganisms were detected, antibiotherapy was limited to cefazolin prophylaxis. If bacterobilia was detected, targeted antibiotherapy was administered for five days. The incidence of sepsis and organ/ space infection in group 2 was 4% compared to 32% and 24% in group 1, respectively (P<0.05). No differences were observed in the remaining morbimortality variables. The most prevalent microorganisms in bile were Enterococcus spp. and Klebsiella spp. In postoperative samples, they only appeared in 4% of cases in group 2 (P<0.05), in favour of Staphylococcus epidermidis, although they were also prevalent in group 1 (28 and 24%, respectively).
Intraoperative Gram staining of bile fluid could be a useful tool to conduct personalised antibiotic therapy in pancreaticoduodenectomy and contribute to the control of infectious complications.
A performance comparison of the fully automated urine particle analyzer UF- 5000 with UF-1000i and Gram staining in predicting bacterial growth patterns in women with uncomplicated urinary tract infections Yang SS, Yang CC, Chen YS, Chang SJ. BMC Urol 2021; 21 (1): 24. doi: 10.1186/ s12894-021- 00791-x.
Staphylococcus aureus, a Gram-positive microorganism.
WWW.PATHOLOGYINPRACTICE.COM SEPTEMBER 2022
This study aims to compare the performance of the new flow cytometer UF-5000 with the UF-1000i and Gram
staining for determining bacterial patterns in urine samples. Women who attended clinic with symptoms suggestive of urinary tract infection were enrolled in the study. Mid- stream urine samples were collected for Gram staining, urine analysis and urine cultures. Bacterial patterns were classified using the UF-1000i (none, cocci bacteria or rods/mixed growth), the UF-5000 (none, cocci, rods or mixed growth) and Gram staining.
Among the 102 samples included,
there were 10 Gram-positive cocci, two Gram-positive bacilli, 66 Gram- negative rods, and 24 mixed growth. The sensitivity/specificity of the UF-1000i was 81.8/91.1% for Gram-negative rods and 23.5/96.9% for cocci/mixed. The sensitivity/specificity of the UF-5000 was 80.0/88.2% for Gram negative rods and 70.0/86.5% for Gram-positive cocci. The UF-5000 demonstrated good sensitivity and specificity for Gram-negative bacilli and demonstrated an improved sensitivity for detecting Gram-positive cocci compared with the UF-1000i.
Gram stain microscopy in septic arthritis Al-Tawil K, Quiney F, Pirkis L, Birkett N, Rooney A. Acta Orthop Belg 2021; 87 (3): 553–6.
Septic arthritis is a serious condition that can lead to rapid destruction of a joint if it is not rapidly diagnosed and treated appropriately. The reported annual incidence is 10 in 100,000 although this increases to 70 in 100,000 in those with risk factors for developing septic arthritis, mainly rheumatoid arthritis and immune- compromised patients.
The aim of this study is to examine the sensitivity and specificity, and thus the clinical usefulness, of Gram stain results. This was a single-centre, retrospective case series. All joint aspirates over a
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