Change in antimicrobial susceptibility of pathogens isolated from surgical site infections over the past decade in Japanese nation-wide surveillance study

Inappropriate antimicrobial therapy for surgical site infections (SSIs) can lead to poor outcomes and an increased risk of antibiotic resistance. A nationwide survey was conducted in Japan from 2018 to 2019 to investigate the antimicrobial susceptibility of pathogens isolated from SSIs. The data were compared with those obtained in 2010 and 2014–2015 surveillance studies. Although the rate of detection of extended-spectrum β-lactamase producing strains of Escherichia coli was increased from 9.5% in 2010 to 23% in 2014–2015, the incidence decreased to 8.7% in 2018–2019. Although high susceptibility rates were detected to piperacillin/tazobactam (TAZ), the geometric mean MICs were substantially higher than to meropenem (2.67 vs 0.08 μg/mL). By contrast, relatively low geometric mean MICs (0.397 μg/mL) were demonstrated for ceftolozane/TAZ. Although the MRSA incidence rate decreased from 72% in the first surveillance to 53% in the second, no further decrease was detected in 2018–2019. For the Bacteroides fragilis group species, low levels of susceptibility were observed for moxifloxacin (65.3%), cefoxitin (65.3%), and clindamycin (CLDM) (38.9%). In particular, low susceptibility against cefoxitin was demonstrated in non-fragilis Bacteroides, especially B. thetaiotaomicron. By contrast, low susceptibility rates against CLDM were demonstrated in both B. fragilis and non-fragilis Bacteroides species, and a steady decrease in susceptibility throughout was observed (59.3% in 2010, 46.9% in 2014–2015, and 38.9% in 2018–2019). In conclusion, Japanese surveillance data revealed no significant lowering of antibiotic susceptibility over the past decade in organisms commonly associated from SSIs, with the exception of the B. fragilis group.     

Reduced tonicity stimulates an inflammatory response in nucleus pulposus tissue that can be limited by a COX‐2‐specific inhibitor

In intervertebral disc herniation with nucleus pulposus (NP) extrusion, the elicited inflammatory response is considered a key pain mechanism. However, inflammatory cytokines are reported in extruded herniated tissue, even before monocyte infiltration, suggesting that the tissue itself initiates the inflammation. Since herniated tissue swells, we investigated whether this simple mechanobiological stimulus alone could provoke an inflammatory response that could cause pain. Furthermore, we investigated whether sustained‐release cyclooxygenase‐2 (COX2) inhibitor would be beneficial in such conditions. Healthy bovine NP explants were allowed to swell freely or confined. The swelling explants were treated with Celecoxib, applied either as a bolus or in sustained‐release. Swelling explants produced elevated levels of interleukin‐6 (IL‐6) and prostaglandin E₂ (PGE₂) for 28 days, while confined explants did not. Both a high concentration bolus and 10 times lower concentration in sustained release completely inhibited PGE₂ production, but did not affect IL‐6 production. Swelling of NP tissue, without the inflammatory system response, can trigger cytokine production and Celecoxib, even in bolus form, may be useful for pain control in extruded disc herniation. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 33:1724–1731, 2015.     

A mutation in the N-terminus of troponin I that is associated with hypertrophic cardiomyopathy affects the Ca(2+)-sensitivity, phosphorylation kinetics and proteolytic susceptibility of troponin

The first human cardiac troponin I (hcTnI) mutation in the N-terminal 32 residue region, R21C (arginine residue number 21 mutated to cysteine), which has been linked to hypertrophic cardiomyopathy (HCM), has recently been reported. The effect of this mutation on the physiological function of hcTnI was investigated. Human cTnI R21C (in the absence or presence of troponin T and troponin C) was phosphorylated by protein kinase A (PKA) at a significantly slower rate than wild-type hcTnI. In skinned fiber studies, the TnI R21C mutant showed a large increase in Ca(2+)-sensitivity of force development when compared to wild-type TnI (DeltapCa(50)=0.33). Phosphorylation of skinned fibers containing TnI R21C by PKA resulted in a significantly smaller decrease in the Ca(2+)-sensitivity of force development when compared to phosphorylation of fibers containing wild-type TnI. The decreased sensitivity of TnI R21C to PKA is most likely due to a decreased ability of PKA to phosphorylate this TnI rather than conformational problems within this TnI. In addition, skinned fibers were found to contain an endogenous kinase that is capable of phosphorylating wild-type TnI. However, the endogenous kinase activity did not affect the Ca(2+)-sensitivity of force development, the Hill coefficient or maximal force of these skinned fibers. Actomyosin ATPase assays showed that the R21C mutation did not affect the inhibitory properties of TnI or the maximal ATPase activity. TnI R21C was also found to be more susceptible to proteolysis by calpain II than wild-type TnI. These results suggest that this R21C mutation in TnI affects the Ca(2+)-sensitizing effect of Tn, the ability of TnI to be readily phosphorylated by PKA and the stability of TnI to calpain. The results also suggest that the N-terminal region may have important roles such as modulating the Ca(2+)-sensitivity of force-development.     

Elevated serum levels of macrophage-derived cytokines precede and accompany the onset of IDDM

Summary To determine whether cytokines could have a role in the development of insulin-dependent diabetes mellitus (IDDM), we measured serum levels of cytokines derived from T helper 1 (interleukin-2 and interferon-), T helper 2 (interleukin-4 and inter-leukin-10) lymphocytes and macrophages (tumour necrosis factor-, interleukin-1 and interleukin-1 ) in patients before and after the onset of IDDM. Recently diagnosed IDDM patients had significantly higher levels of interleukin-2, interferon-, tumour necrosis factor- and interleukin-1 than patients with either long-standing IDDM, non-insulin-dependent diabetes (NIDDM), Graves' disease, or control subjects (p<0.05 for all). Compared with control subjects, patients with long-standing IDDM and those with NIDDM had higher interleukin-2 and tumour necrosis factor- levels (p<0.01 for all). Interleukin-4 and interleukin-10 were detectable in sera of patients with Graves' disease only, while interleukin-1 was not detectable in the serum of any control or test subject. To investigate whether high cytokine levels precede the onset of IDDM, we studied 28 non-diabetic identical co-twins of patients with IDDM, followed-up prospectively for up to 6 years after the diagnosis of the index. Levels of tumour necrosis factor- and interleukin-1 were elevated above the normal range more frequently in the eight twins who developed diabetes than in those 20 who did not (p<0.005). Analysis of T helper 1 and T helper 2 profiles of the twin groups did not reveal a clear difference between prediabetic twins and twins remaining non-diabetic. These results support the notion that T helper 1 lymphocytes may play a role in the development of IDDM. This is associated with release of macrophage-derived cytokines, which is also a feature of the prediabetic period. The lack of evidence of a dominant T helper 1 profile of cytokine release before diabetes onset suggests that additional events, activating this arm of the cellular immune response, are required in the immediate prediabetic period.Abbreviations IL Interleukin - IFN- interferon-gamma - T_H T helper - ICA islet-cell antibody - GAD glutamic acid decar-boxylase - IDDM insulin-dependent diabetes mellitus - NIDDM non-insulin-dependent diabetes mellitus - TNF- tumour necrosis factor-alpha - CTLL-16 murine cytotoxic cell line     

A patient undergoing pancreaticoduodenectomy in whom involved common hepatic artery anomalously arising from the superior mesenteric artery was removed and reconstructed

Identifying anatomical variations of the celio-mesenteric arterial branches is important when performing pancreaticoduodenectomy. A relatively rare variation is the common hepatic artery entirely originated as a branch of the superior mesenteric artery. This type of variation is termed hepatomesenteric trunk type common hepatic artery, in which an accessory left hepatic artery arising from the celiac trunk is absent. Preservation of hepatomesenteric trunk type common hepatic artery is indispensable during pancreaticoduodenectomy because fatal hepatic injury or leak of hepaticojejunostomy can occur. The present case report shows a patient with pancreatic head tumor in whom hepatomesenteric trunk type common hepatic artery was involved by the tumor. The patient underwent pancreaticoduodenectomy during which the involved hepatomesenteric type common hepatic artery was removed and reconstructed using saphenous venous grafts. Histopathological examination showed double cancers which were composed of an advanced ductal adenocarcinoma of the pancreas and early bile duct adenocarcinoma. The patient is alive 18 months after the surgery without recurrence.     

Endoscopic ultrasonography-guided transmural drainage of an infected hepatic cyst due to Edwardsiella tarda: a case report

Infected hepatic cysts are very rare compared to simple liver cysts and abscesses. We treated a 77-year-old man with an infected hepatic cyst in the lateral segment caused by Edwardsiella tarda, which has not been previously reported as a pathogenic organism associated with infected hepatic cysts. Percutaneous drainage was temporarily effective, but infection recurred after the drainage tube was removed. We then inserted two drainage tubes into the cyst using an endoscopic ultrasonography (EUS)-guided technique, which was developed from EUS-guided fine needle aspiration (EUS-FNA). The internal drainage tube was a 7 Fr double pigtail stent, and the external tube was a 6 Fr nasobiliary drainage tube. Lavage through the external drainage tube was carried out for one week. The external drainage tube was discontinued when the patient’s condition improved significantly. Sixteen days after tube insertion, he was discharged with the internal tube draining the hepatic cyst into the stomach. Fifteen months after EUS-guided drainage, CT examination showed no recurrence of the hepatic cyst. EUS-guided drainage is an effective treatment for infected hepatic cysts.