Hypoprothrombinemia associated with cefmetazole

Effectiveness of cefmetazole versus meropenem for invasive urinary tract infections caused by extended-spectrum β-lactamase-producing Escherichia coli

Cefmetazole is active against extended-spectrum β-lactamase-producing Escherichia coli (ESBLEC) and is a potential candidate for carbapenem-sparing therapy. This multicenter, observational study included patients hospitalized for invasive urinary tract infection due to ESBLEC between March 2020 and November 2021 at 10 facilities in Japan, for whom either cefmetazole or meropenem was initiated as a definitive therapy within 96 h of culture collection and continued for at least 3 d. Outcomes included clinical and microbiological effectiveness, recurrence within 28 d, and all-cause mortality (14 d, 30 d, in-hospital). Outcomes were adjusted for the inverse probability of propensity scores for receiving cefmetazole or meropenem. Eighty-one and forty-six patients were included in the cefmetazole and meropenem groups, respectively. Bacteremia accounted for 43% of the cefmetazole group, and 59% of the meropenem group. The crude clinical effectiveness, 14 d, 30 d, and in-hospital mortality for patients in the cefmetazole and meropenem groups were 96.1% vs 90.9%, 0% vs 2.3%, 0% vs 12.5%, and 2.6% vs 13.3%, respectively. After propensity score adjustment, clinical effectiveness, the risk of in-hospital mortality, and the risk of recurrence were similar between the two groups (P = 0.54, P = 0.10, and P = 0.79, respectively). In all cases with available data (cefmetazole : n = 61, meropenem : n = 22), both drugs were microbiologically effective. In all isolates, bla CTX-M was detected as the extended-spectrum β-lactamase gene. The predominant CTX-M subtype was CTX-M-27 (47.6%). Cefmetazole showed clinical and bacteriological effectiveness comparable to meropenem against invasive urinary tract infection due to ESBLECs.

A Case of Alveolar Bleeding from Clotting Abnormality by Cefmetazole

Cephalosporins are one of the most commonly used first-line antibiotics. In this report, we describe the case of a patient who developed alveolar bleeding due to clotting abnormality following the use of cefmetazole, one of cephalosporins containing an N-methylthiotetrazole (NMTT) side chain. Compared to other antibiotics, cephalosporins with an NMTT side chain cause a higher degree of bleeding events. The bleeding tendency is caused by the depletion of vitamin K-dependent clotting factors via inhibition of the vitamin K epoxide reductase. This mechanism of action is the same as warfarin. Recent years have seen an increase in the number of patients using direct oral anticoagulants that do not require coagulation tests. As a consequence, there may be an increase in the number of bleeding events due to anticoagulant drugs and such antibiotics coprescription. Therefore, this case is an instructive lesson.

A suspicious case of cefmetazole-induced hypoprothrombinemia

Cefmetazole occasionally prolongs the prothrombin time. The mechanism is considered to be because of (i) inhibition of vitamin K metabolism, (ii) a lack of vitamin K, and (iii) low vitamin K stores. We report the death of a 93-year-old woman who was administered cefmetazole and exhibited a prolonged prothrombin time. When using cefmetazole in elderly patients, PT-INR should be monitored every few days.

Use of Hypoprothrombinemia-Inducing Cephalosporins and the Risk of Hemorrhagic Events: A Nationwide Nested Case-Control Study

Objective

Existing data regarding the risk of hemorrhagic events associated with exposure to hypoprothrombinemia-inducing cephalosporins are limited by the small sample size. This population-based study aimed to examine the association between exposure to hypoprothrombinemia-inducing cephalosporins and hemorrhagic events using National Health Insurance Research Database in Taiwan.

Design

A nationwide nested case-control study.

Setting

National Health Insurance Research database.

Participants

We conducted a nested case-control study within a cohort of 6191 patients who received hypoprothrombinemia-inducing cephalosporins and other antibiotics for more than 48 hours. Multivariable conditional logistic regressions were used to calculate the adjusted odds ratio (aOR) and 95% confidence interval (CI) for hemorrhagic events associated with exposure to hypoprothrombinemia-inducing cephalosporins (overall, cumulative dose measured as defined daily dose (DDD), and individual cephalosporins).

Results

Within the cohort, we identified 704 patients with hemorrhagic events and 2816 matched controls. Use of hypoprothrombinemia-inducing cephalosporins was associated with increased risk of hemorrhagic events (aOR, 1.71; 95% CI, 1.42–2.06), which increased with higher cumulative doses (<3 DDDs, aOR 1.62; 3–5 DDDs, aOR 1.78; and >5 DDDs, aOR 1.89). The aOR for individual cephalosporin was 2.88 (95% CI, 2.08–4.00), 1.35 (1.09–1.67) and 4.57 (2.63–7.95) for cefmetazole, flomoxef, and cefoperazone, respectively. Other risk factors included use of anticoagulants (aOR 2.08 [95% CI, 1.64–2.63]), liver failure (aOR 1.69 [1.30–2.18]), poor nutritional status (aOR 1.41 [1.15–1.73]), and history of hemorrhagic events (aOR 2.57 [1.94–3.41]) 6 months prior to the index date.

Conclusions

Use of hypoprothrombinemia-inducing cephalosporins increases risk of hemorrhagic events. Close watch for hemorrhagic events is recommended when prescribing these cephalosporins, especially in patients who are at higher risk.

Effect of Fasting on Coagulation Factors in Patients who Undergo Major Abdominal Surgery

Major abdominal surgery without preoperative adequate oral intake with some cephalosporins may result in vitamin K deficiency and bleeding tendency. The aim of this study is to clarify the effect of preoperative fasting on postoperative coagulation factors. We prospectively examined 16 patients who underwent major abdominal surgery. Patients were divided into a preoperative fast group (Group F, n = 7, mean period of preoperative fasting 8.7 days) and a control group (Group C, n = 9). We did not administer vitamin K and initiated feeding after the seventh postoperative day. In Group C, prothrombin time (PT) and Factors II, VII, IX, and X levels were decreased after the surgery to within normal limits. In Group F, the PT and Factors II, VII, and X levels were decreased after the surgery. Abnormal lower levels of PT and Factors II, VII, and X were seen in 67, 33, 67, and 67 per cent of patients after the surgery, respectively. Factors VII and X levels were higher than in Group C by the third postoperative day. The protein induced by vitamin K absence or antagonist-II levels in Group F were increased at all postoperative points. Clinicians should realize that preoperative fasting for as little as 1 week can induce precoagulopathy, resulting in postoperative coagulopathy after major surgery.

Protein C deficiency in microvascular head and neck reconstruction

OBJECTIVE

To determine the incidence of perioperative protein C deficiency in patients undergoing free flap reconstruction of cancer-related defects in the head and neck.

STUDY DESIGN

Prospective case series.

INTERVENTION

Ten patients underwent microvascular reconstruction after surgical therapy of carcinomas of the oral cavity or oropharynx. Coagulation studies were determined in all patients 72 hours after surgery.

SETTING

Academic tertiary care medical center

RESULTS

Protein C deficiency was detected in 70% of patients. One free flap failure was attributed to protein C deficiency.

CONCLUSIONS

Vitamin K-dependent clotting factors are frequently deficient during the postoperative period after major head and neck surgery, which may result in a state of hypercoagulability. Protein C deficiency should be considered as a possible cause of free flap thrombosis in patients who undergo microvascular head and neck reconstruction.