Preface

The kidneys, ureters, bladder, and urethra play an important role not only in urine production and transport but also in preventing the invasion of pathogens. In this book, experts from different countries demonstrate clinical and research advances in nephropathy and urinary tract infection.

Membranous nephropathy is a kind of antibody-mediated autoimmune glomerular disease. In their chapter, Dr. Omar Ragy et al. present the gene polymorphism in patients with membranous nephropathy, as well as discuss the value of proteomics and transcriptomic analysis in managing the disease. These modern techniques of analysis make it possible to minimize patients' immunosuppression exposure and identify the most effective targeted immunosuppressive therapy for each patient.

Diabetic nephropathy is a common cause of end-stage kidney disease. Interestingly, not all patients with diabetes mellitus will develop diabetic nephropathy. In their chapter, Drs. Elfiani Elfiani and Huntari Harahap present a cross-sectional comparative study to identify potential biomarkers for the occurrence of diabetic nephropathy.

A kidney transplant is considered the best treatment for patients with end-stage kidney disease. However, some conditions, such as antibody-mediated rejection and recurrent focal segmental glomerulosclerosis, may result in graft failure. Therapeutic apheresis is believed to be an effective treatment for managing these conditions since it can remove donor-specific antibodies and other circulating factors. In their chapter, Drs. Jean Jeanov Filipov and Emil Paskalev Dimitrov demonstrate the current evidence on the application of therapeutic apheresis.

Apart from urine transport, storage, and elimination, the urinary tract also acts as a barrier preventing pathogens from invading. Once pathogens break through the barrier, people will suffer from urinary tract infections. Due to the wide use of antibiotics, some bacteria have developed resistance to these drugs. In their chapter, Dr. Akosua Bonsu Karikari et al. present the characteristics of multidrug-resistant organisms isolated from patients with urinary tract infections in Northern Ghana.

Escherichia coli is the common pathogen causing urinary tract infection. Multidrug-resistant Escherichia coli has attracted broad attention. Dr. Shiela Chetri points out multidrug efflux pumps encoded in the microorganism's chromosomes are the main antibiotic-resistant mechanism in *E. coli*.

*Acinetobacter baumannii* is a kind of opportunistic bacteria related to hospitalacquired infection. In their chapter, Dr. Hussein O.M. Al-Dahmoshi et al. reveal the virulence factors of *A. baumannii* resulting in urinary tract infection. This information allows clinicians to develop targeted treatment strategies.

Besides the evolution of bacterial virulence, some conditions can also cause the body to be susceptible to urinary tract infection. Of those, pregnancy is one of the most common since it may result in temporary ureteral dilation and hydronephrosis. In their chapter, Drs. Muhamed Ali Al Kabe and Eman Th. Nadhaif Al-Fatlawy perform a case-control study that shows pregnant women are at significantly increased risk of bacteriuria.

An intact urothelium and a normal anatomical structure of the urinary tract are the foundation of a powerful barrier. Iatrogenic injury is a common factor that impairs epithelial integrity and consequently weakens the function of the barrier. In general, ureteric injuries in gynecology surgery are one of the most common Iatrogenic injuries of the urinary tract. Dr. Rama Garg presents the diagnosis, treatment, and prevention of ureteric injury in gynecology surgery.

Although this book does not cover all aspects of urinary tract infection and nephropathy, it provides readers with important updates.

> **Ran Pang** Department of Urology, Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, China

Section 1 Introduction


**5. Cannery wastewater treatment with anaerobic-anoxic-aerobic system**

Anoxic process is widely used in wastewater treatment. Anoxic means depletion or deficiency of oxygen. Anoxic process is a biological treatment process by which NO3-N is converted to molecular nitrogen gas in the absence of oxygen.

A system comprised of anaerobic-anoxic-aerobic reactors was tested to treat the wastewater from tuna cooker. This wastewater stream is characterized by high COD and N concentrations. The up-flow anaerobic sludge blanket reactor was used to achieve the anaerobic digestion in a two-step process. In the first, the COD concentration was varied and ORLs up to 4 g COD/(l.d) were achieved. In the second step, the 6 g COD/l and the HRT were varied between 0.5 and 0.8 day, and this step led to ORLs less than 15 g COD/(l.d). The denitrification process was carried out in an upflow anoxic filter, and the result of the project indicated that the efficiency of this process is dependent on the supplied carbon content. For optimum carbon content, the ratio between the COD and N equalled 4 and the denitrification percentage equalled 80%. Finally, the nitrification was reported to be fixed at 100% ammonia removal regardless of the amount of carbon in the range of 0.2–0.8 g TOC/l. The variation of the recycling ratios between the denitrification and nitrification reactors in the range of 1–2.5 was found to affect the efficiency of the COD and N-removal percentage, where 90 and 60% removal for COD and N was reported at recycling ratio between 2 and 2.5 [15].