In young individuals (age, ≤35 years) urethritis and orchiepididymitis are usually caused by sexually transmitted pathogens such as Neisseria gonorrhoeae and Chlamydia trachomatis. However, Escherichia coli is the most common cause of orchiepididymitis in older patients, as the origin of the pathogen being in the urinary tract. The infection in this older-age group is thought to be associated with obstructive urinary tract disease.1 The unexpected detection of E. coli in a young patient with urethritis and orchiepididymitis who had a normal urinary tract prompted an investigation of a possible sexual acquisition of the infection.
A 30-year-old man presented with urethral discharge and left testicular pain. A day after having a sexual intercourse with his steady girlfriend, the patient experienced a tingling sensation in the urethra which was followed the next day by dysuria and a milky urethral discharge. There were no symptoms of frequency, urgency, or suprapubic pain. On the third day, a left testicular pain occurred, which prompted a visit to the emergency room. On examination, urethral discharge was noted, and the left epididymis was very sensitive on palpation. The temperature was 37.0°C, leukocytes in urine were 500/mL, C-reactive protein was 2.5 mg/dL, and white blood cells count was 11,000/ mm3. Acute epididymitis was diagnosed and the patient received a single dose of ceftriaxone 1.0 g, intramuscularly, after urethral discharge and urine specimens were obtained for culture. The urethral discharge sample was plated onto the following culture media: New York State (NYS) agar, blood agar, and MacConkey agar. Urine was cultured on chrome agar and blood agar. He was discharged with a prescription for doxycycline 100 mg orally twice a day, for 7 days. E. coli grew in both urethral and urine cultures, susceptible to all antimicrobial agents tested. He returned to the emergency room on the next day because the testicular pain worsened and the urethral discharge persisted. The left testis was red, warm, and very sensitive on palpation. His temperature was 38.3°C, white blood cells count was 17,500/mm3, and C-reactive protein was 11.14 mg/dL. Ciprofloxacin 500 mg, twice a day was initiated and switched later to trimethoprim–sulfamethoxazole 960 mg orally, twice a day, when the results of antibiotic susceptibility were available. Ultrasound examination revealed an enlarged and hyperemic left testis; the epididymis was also enlarged and very hyperemic, and small amount of fluid was detected in the scrotum. The urinary tract appeared normal. The urethral discharge disappeared, and 3 days later there was no pyuria; repeat urethral culture was sterile. The testicular pain regressed gradually and the inflammatory markers returned to normal values. Classic sexually transmitted pathogens, including Neisseria gonorrhoeae, Chlamydia trachomatis, Mycoplasma genitalium, Ureaplasma urealyticum, and Trichomonas vaginalis, were excluded by urine polymerase chain reaction (PCR) using Seeplex STD6 ACE Detection kit (Seegene, Inc., Seoul, Korea).
The patient was circumcised and had a steady female sexual partner for the preceding 3 years. He denied being sexually involved with other women or men during the same period and did not practice anal sex at any time. He had no history of sexually transmitted infections. The patient's girlfriend was asymptomatic although she had a history of recurrent urinary tract infections (UTIs). Her urine culture was sterile; however, vaginal culture grew E. coli with the same antibiotic susceptibility. Urine PCR was negative for N. gonorrhoeae and C. trachomatis. The couple did not have sexual relations from the moment the man became symptomatic and until his recovery.
The isolates from the patient and his girlfriend were sent for further characterization of Enterobacteriaceae to the National Reference Laboratory, Jerusalem, Israel. Serotyping of O antigen was performed by classic methods.2 Pulsed-field gel electrophoresis (PFGE) was performed using a method previously described.3 Genomic DNA was prepared in agarose plugs and digested with XbaI, using standardized methods.4 The E. coli isolates from the patient and his partner were tested by PCR for the presence of the following marker virulence genes ompT, malX, papC, and iroN.5E. coli strain 536 (serotype O6:K15:H31)6 was used as a positive control for all 4 genes.
E. coli grew from the urethral discharge on all culture media used, except NYS. The isolates from both partners belonged to serotype O78 and had identical PFGE pattern (Fig. 1).
Our findings highly suggest that the E. coli responsible for the urethritis and orchi-epididymitis in this young man was sexually acquired from his female partner. The couple's isolates were identical regarding their antibiotic susceptibility pattern, serotype PFGE pattern, and their urothopathogenic virulence markers. Moreover, other risk factors that might explain urogenital E. coli acquisition such as anal intercourse, homosexual activity, or noncircumcision,7 were absent.
Sexual transmission of E. coli from women with history of UTIs to their male partners has been reported in a few instances.8–10 In all these cases, the clinical presentation in the infected men was either that of cystitis or pyelonephritis, and the relatedness between the infectious episodes in the couples was based on the temporal closeness of the events and the similarity of serotypes and the antibiotic susceptibility patterns of the isolates in each couple. Probable sexual transmission of E. coli from a husband to his wife, was also reported.11 The authors postulated that the wife with recurrent episodes of cystitis was reinfected from her husband who had recurrent attacks of acute prostatitis. The E. coli isolates from the couple had identical antibiotic susceptibility pattern, biotype, and serotype (O6). Foxman et al have studied the transmission of uropathogenic E. coli between sex partners—the organism was found in random initial voids in 4 of 19 of the most recent male sex partner of women with UTI. In each case, the E. coli isolated from the man was identical by PFGE and bacterial virulence profile to the urinary E. coli from his sex partner.12 The likelihood of sharing uropathogenic E. coli between sex partners was found to be higher when the woman had UTI than in couples in whom the woman did not have UTI.13
In men, the association between E. coli and urethritis was documented in a study of UTI in mostly homo- and bisexual individuals. In 62% of cases urethritis presented in addition to or preceding cystitis; cultures were negative for C. trachomatis and N. gonorrhoeae. Rectal insertive intercourse was suggested as a possible mechanism of E. coli acquisition although sex partners were not studied. The putative pathogen was cultured only in urine samples and was not sought in urethral discharge cultures.14 In contrast, in a study of the urethral bacteriology in 33 normal men and 69 men with nongonococcal urethritis seen at a sexually transmitted disease clinic, E. coli was isolated in a single person with no urethritis and in none of those with nongonococcal urethritis.15 The sexual orientation of the individuals included in the study was not indicated.
Sexual acquisition of E. coli, either heterosexually or homosexually, usually causes UTI and less often urethritis. In all previous reports of the association between sexual transmission of E. coli and urethritis, the pathogen was isolated from urine samples and there was no attempt to detect it in the urethral discharge. The present case provides the first well-documented evidence of culture-confirmed urethritis and orchiepididymitis caused by sexually acquired uropathogenic E. coli. Although of probably rare occurrence, the possibility of E. coli involvement in nongonococcal urethritis and orchiepididymitis should be considered even in circumcised heterosexual young men not practicing anal intercourse. It should be pointed out that the media routinely used for gonococcal cultures (NYS agar and Thayer Martin agar) contain antibiotics that would suppress the growth of most Enterobacteriaceae and, therefore, can miss cases of E. coli urethritis.
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