
==== Front
Case Rep Womens Health
Case Rep Womens Health
Case Reports in Women's Health
2214-9112
Elsevier

S2214-9112(24)00066-3
10.1016/j.crwh.2024.e00645
e00645
Article
Peritonitis caused by Mycoplasma hominis after laparoscopic total hysterectomy: A case report
Yagi Koki kyagih3@aih-net.com
⁎
Lee Lifa
Abe Naoki
Kira Sachino
Hayashi Sotaro
Takeuchi Hajime
Nishiyama Satoshi
Goto Maki
Tsujioka Hiroshi
Department of Obstetrics and Gynecology, Aso Iizuka Hospital, Iizuka, Japan
⁎ Corresponding author at: Department of Obstetrics and Gynecology, Aso Iizuka Hospital, 3-83 Yoshio-machi, Iizuka, Japan. kyagih3@aih-net.com
22 8 2024
10 2024
22 8 2024
43 e0064513 8 2024
16 8 2024
19 8 2024
© 2024 The Authors
2024
https://creativecommons.org/licenses/by-nc-nd/4.0/ This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
Infections after obstetric and gynecologic surgery are commonly caused by enterobacteria, commensal vaginal bacteria, or indigenous skin bacteria (primarily Staphylococcus aureus and Streptococcus). Mycoplasma hominis (M. hominis) rarely causes postoperative infection in the field of obstetrics and gynecology and its treatment is generally delayed. This report describes a case report of peritonitis caused by M. hominis after laparoscopic total hysterectomy. A 44-year-old patient (gravida 1, para 1) presented with heavy menstrual bleeding and severe anemia. She was diagnosed as having multiple uterine fibroids and bilateral endometriomas and underwent laparoscopic surgery. She subsequently developed postoperative peritonitis due to M. hominis. This microorganism was identified in the postoperative cultures of the vaginal discharge and the transvaginal drainage fluid by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The patient was treated successfully with the appropriate antimicrobial agents. It is important to consider M. hominis infection when gynecological postoperative infection persists despite treatment with beta-lactam antibiotics, and no causative organisms are identified by Gram staining.

Highlights

• Infections after gynecologic surgery are commonly caused by enterobacteria and commensal vaginal and skin bacteria.

• Mycoplasma hominis is known to be endemic in the urogenital area.

• M. hominis infection should be considered when inflammation resistant to beta-lactams after gynecologic surgeries.

Keywords

Endometrioma
Peritonitis
Mycoplasma hominis
Laparoscopic hysterectomy
==== Body
pmc1 Introduction

Mycoplasma hominis (M. hominis) is known to be endemic in the urogenital area. It is undetectable by Gram staining because the organisms have no cell walls. Further, beta-lactam antibiotics are ineffective. Bacteria commonly causing infections after obstetric and gynecologic surgery comprise enterobacteria (primarily Escherichia coli), commensal vaginal bacteria (primarily Bacteroides fragilis), and indigenous skin bacteria (primarily Staphylococcus aureus and Streptococcus). M. hominis is rarely identified as the cause of postoperative infections, often resulting in delay in treatment [1]. This report concerns a case of peritonitis caused by M. hominis after laparoscopic total hysterectomy. The features of postoperative infections caused by the organism are described.

2 Case Presentation

A 44-year-old woman, gravida 1, para 1, presented with heavy menstrual bleeding with severe anemia (hemoglobin 63 g/L). Magnetic resonance imaging revealed multiple uterine fibroids of various sizes (maximum 40 mm) within the myometrium and submucosa and bilateral endometriomas, 80 mm in size on the right side and 20 mm on the left. The initial treatment was supplementary iron for anemia, followed by transvaginal ultrasound of the uterus and ovaries. The anemia improved after the patient took 2 mg/day of dienogest (progestin monotherapy) for approximately 6 months. However, heavy menstrual bleeding persisted and transvaginal ultrasound showed enlargement of her ovarian lesions. Surgery was thus indicated.

First, the vaginal cavity was washed out with 1000 mL of normal saline and 1 g of the antimicrobial agent cefmetazole was administered. Total laparoscopic hysterectomy and bilateral salpingo-oophorectomy using a uterine manipulator were performed. Intraoperatively, a left ovarian cyst ruptured and its contents drained into the abdominal cavity; otherwise the surgery was completed as planned. Pathological examination of the removed tissues resulted in diagnoses of uterine fibroids and bilateral endometriomas.

The postoperative course, including white cell count, Numerical Rating Scale scores, and body temperature, is shown in Fig. 1. On postoperative day (POD) 4, the patient was discharged from hospital because she was progressing well; however, she developed a fever and lower abdominal pain during her first night at home. On POD 5, her temperature was 38.0 °C and her abdomen soft, with tenderness under the navel and right lower abdomen on palpation, prompting readmission for management of postoperative complications. The surgical incision appeared to be healing satisfactorily. On vaginal examination, there was a small amount of brownish discharge without pus and no tenderness at the site of the vaginal stump or vaginal cuff dehiscence. Blood tests showed a slight increase in her white cell count (9470/μL) with a high serum concentration of C-reactive protein (11.3 mg/dL). Urinalysis showed no evidence of urinary tract infection. Samples of blood, urine, and vaginal discharge were submitted for culture on the first day of readmission. Transvaginal ultrasound showed a 32 × 16 mm low echoic lesion in the right side of the vaginal stump (Fig. 2). Transvaginal drainage targeting the lesion was performed. The fluid drained showed no pus; however, a brownish hematoma was aspirated and sent for culture. Enhanced computed tomography (CT) on POD 5 revealed fluid density in the pelvic cavity, thickness of the intestinal wall and a misty mesentery sign, which are indicative of peritonitis and pelvic abscess.Fig. 1 Postoperative course, including changes in white blood cell count, Numerical Rating Scale scores, body temperature and timing of antimicrobials, computed tomography scans, and transvaginal drainage.

BT, body temperature; CT, computed tomography; NRS, Numerical Rating Scale scores; POD, postoperative day; WBC, white blood cell count.

Fig. 1

Fig. 2 Transvaginal ultrasound showing a low echoic 32 × 16 mm lesion in the right pelvic cavity (arrowheads).

Fig. 2

Intravenous sulbactam/ampicillin 3 g three times a day was started on the first day of readmission; however, the abdominal pain and fever persisted for more than a week. The department of infectious diseases was consulted because of the difficulty in treating the patient. No causative organisms were detected in the culture specimens. The common bacteria causing intra-abdominal abscesses were covered, and the same antimicrobial regimen was continued with possible drainage. On POD 11, a repeat transvaginal ultrasound performed because of the patient's persistent fever and lower abdominal pain showed that the hypoechoic lesion detected on readmission was unchanged. Another sample of serous bloody vaginal discharge was submitted for culture. By POD 12, no pathogens had been cultured from the blood, vaginal discharge or drainage fluid. A repeat CT scan on POD 13 (Fig. 3) showed ascites around the liver and worsening peritonitis. A capsule had formed around the fluid density in the pelvic cavity, the intestinal wall had thickened, and the misty mesentery sign was more pronounced.Fig. 3 Computed tomography images showing ascites around the liver and worsening peritonitis (arrows). A capsule has formed around the fluid density in the pelvic cavity, the intestinal wall has thickened, and the misty mesentery sign is more pronounced (arrowheads).

Fig. 3

In view of the CT scan findings, the possibility of mycroperforation of the intestine during surgery was considered. The patient therefore ceased her oral intake and another transvaginal drainage was performed. On POD 17, cultures of the vaginal discharge from POD 11 and the transvaginal drainage fluid from POD 13 showed tiny colonies; however, Gram staining failed to detect any organisms. Mass spectrometry revealed M. hominis in these cultures. On POD 17, therapy with oral doxycycline (100 mg twice a day) was started, following which infection-related variables declined rapidly and there were no further temperature spikes. Transvaginal ultrasound showed that the previously detected hypoechoic lesion had resolved completely. Intravenous sulbactam/ampicillin 3 g three times a day was continued during this period. The patient was discharged 4 days after commencing doxycycline administration, her general condition having markedly improved.

3 Discussion

This report presents a case of infection caused by M. hominis after laparoscopic total hysterectomy. Mycoplasma species have only a cell membrane and no cell wall, preventing Gram staining. They are resistant to beta-lactams, which are cell wall synthesis inhibitors frequently used to treat postoperative infections. Mycoplasma pneumoniae, a well-known representative of the genus Mycoplasma, is established in the human mucosa. There are also many other clinically important species, including M. hominis, M. genitalium, and M. fermentans [2,3]. M. hominis, a commensal urogenital organism, is carried by 25% to 67% of the general female population. It has been suggested that the rate of colonization by this pathogen is related to sexual activity. The infection rate is significantly higher in younger than in older women [4]. Of note, detection of M. hominis does not necessarily indicate pathology.

There have been several reports of obstetric and gynecological infections caused by M. hominis related to pelvic inflammatory disease, postpartum fever, preterm labor, and postoperative infection after cesarean section [[4], [5], [6], [7]]. However, there are few reports of cases of M. hominis infection after laparoscopic total hysterectomy. This report describes a case of peritonitis caused by M. hominis. In this patient, M. hominis was identified in a vaginal culture, suggesting that it may have been a commensal organism. It is possible that implementation of a uterine manipulator after an endometrioma ruptured intraoperatively caused a retrograde infection from the vagina into the abdominal cavity. Therefore, the possibility of postoperative infection with M. hominis should be considered after laparoscopic gynecologic surgery, similarly to infection with this organism after cesarean section. In addition, a ruptured endometrioma, use of a uterine manipulator, retrograde infection via the vaginal cuff communication and transvaginal drainage are possible risk factors for this infection.

Because M. hominis cannot be detected by Gram staining, it is difficult to identify in a direct smear from a specimen. M. hominis is the only genus of Mycoplasma that can grow on ordinary media; however, it is slow-growing, taking at least 72 h to form visible colonies. These colonies are characteristically tiny and granular [8]. Therefore, if a culture is terminated at 42 h, this infection may be missed. Given that it has been estimated that few institutions incubate all specimens for more than 72 h, many M. hominis infections are likely missed. In addition, even when growth of the organism is observed, it is difficult to identify because the microcolonies that grow on the culture medium do not take up Gram stain. In the present case, because M. hominis was not expected, the first vaginal specimen was incubated for too short a time to detect this organism. Molecular-based techniques using sensitive polymerase chain reaction testing and 16S rRNA can identify it [9], as can matrix-assisted laser desorption/ionization time-of-flight mass spectrometry [10]. When the incubation time of the specimens collected on POD 11 and 13 was extended, small colonies formed and M. hominis was identified by mass spectrometry of these colonies.

Because M. hominis does not have cell walls, it is resistant both to therapies that target peptidoglycan synthesis, such as cephalosporins, beta-lactams and glycopeptides, and to other classes of antibiotics, such as aminoglycosides, sulfonamides, and trimethoprim. Tetracyclines, fluoroquinolones, and clindamycin are commonly effective against M. hominis. However, there have recently been some reports of its resistance to tetracyclines, so antimicrobial agents should be selected carefully on the basis of sensitivity testing [11].

In obstetrics and gynecology, beta-lactams are generally administered as perioperative antibacterial agents. These agents are ineffective against M. hominis and would not prevent perioperative infection with this microorganism. Therefore, as in the present case, M. hominis infection should be considered when inflammation does not improve despite administration of beta-lactams in patients who have undergone gynecologic surgeries. It is then necessary to incubate cultures for longer, perform polymerase chain reaction testing and mass spectrometry, and consider substituting effective antimicrobial agents, such as tetracyclines, as soon as possible.

Contributors

Koki Yagi contributed to patient care, date collection, and drafting the manuscript.

Lifa Lee, Naoki Abe, Sachino Kira, Sotaro Hayashi, Hajime Takeuchi, Satoshi Nishiyama, and Maki Goto contributed to revising the article critically for important intellectual content.

Hiroshi Tsujioka contributed to patient care and revising the article critically for important intellectual content.

All authors approved the final submitted manuscript.

Funding

This work did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Patient consent

The patient gave consent for this case report to be published.

Provenance and peer review

The article was not commissioned and was peer reviewed.

Acknowledgements

We thank Dr. Trish Reynolds, MBBS, FRACP, from Edanz (https://jp.edanz.com/ac) for editing a draft of this manuscript.

Conflict of interest statement

The authors declare that they have no conflict of interest regarding the publication of this case report.
==== Refs
References

1 Koshiba H. Koshiba A. Daimon Y. Noguchi T. Iwasaku K. Kitawaki J. Hemotoma and abcess formation caused by Mycoplasma hominis following cesarean section Int. J. Women’s Health 3 2011 15 18 21339933
2 Murray P.R. Baron E.J. Jorgenson J.H. Pfaller M.A. Yolken R.H. Manual of Clinical Microbiology 8th ed. 2003 American Society for Microbiology Washington D.C
3 Sasaki Y. Ishikawa J. Yamashita A. Oshima K. Kenri T. Furuya K. The complete genomic sequence of Mycoplasma penetrans, an intracellular bacterial pathogen in humans Nucleic Acids Res. 30 23 2001 Dec 5293 5300
4 Capoccia R. Greub G. Baud D. Ureaplasma urealyticum, Mycoplasma hominis and adverse pregnancy outcomes Curr. Opin. Infect. Dis. 26 3 2013 Jun 231 240 23587772
5 Mårdh P.A. Weström L. Tubal and cervical cultures in acute salpingitis with special reference to Mycoplasma hominis and T-strain mycoplasmas Brit. J. Venereal Dis. 46 3 1970 Jun 179 186 4988097
6 Mccormack W.M. Rosner B. Lee Y.H. Rankin J.S. Lin J.S. Isolation of genital mycoplasmas from blood obtained shortly after vaginal delivery Lancet J. 1 7907 1975 Mar 596 599
7 Nasser S. Husseini A. Mycoplasma hominis abscesses after caesarean section: a rare complication of a common procedure BMJ Case Rep. 14 7 2021 Jul e244128
8 Nishio M. Miyaki Y. Ogawa Y. Osugi T. Morioka H. A case of sepsis caused by intra abdominal infection with Mycoplasma hominis after Caesarean section J. Jpn. Soc. Clin. Microbiol. 27 1 2017 23 28
9 Taylor-Robinson D. Lamont R.F. Mycoplasmas in pregnancy BJOG 118 2 2024 164 174
10 Pailhories H. Rabier V. Eveillard M. Mahaza C. Joly-Guillou M.-L. Chennebault J.-M. A case report of Mycoplasma hominis brain abscess identified by MALDI-TOF mass spectrometry Int. J. Infect. Dis. 166–168 2014 Dec
11 Pachunka J. Richard H. Mycoplasma hominis necrotising pneumonia in an immunocompetent adult male BMJ Case Rep. 16 6 2023 Jun
