The role of bacterial vaginosis in infection after major gynecologic surgery

Metronidazole and cefazolin vs cefazolin alone for surgical site infection prophylaxis in gynecologic surgery at a comprehensive cancer center

BACKGROUND

Surgical site infection is one of the most common complications of gynecologic cancer surgery. Current guidelines recommend the administration of cefazolin preoperatively to reduce surgical site infection rates for patients undergoing clean-contaminated surgeries such as hysterectomy.

OBJECTIVE

To evaluate the impact of a quality improvement project adding metronidazole to cefazolin for antibiotic prophylaxis on surgical site infection rate for women undergoing gynecologic surgery at a comprehensive cancer center.

STUDY DESIGN

This retrospective, single-center cohort study included patients who underwent surgery in the gynecologic oncology department from May 2017 to June 2023. Patients with penicillin allergies and those undergoing concomitant bowel resections and/or joint cases were excluded. The preintervention group patients had surgery from May 2017 to April 2022, and the postintervention group patients had surgery from April 2022 to June 2023. The primary outcome was a 30-day surgical site infection rate. Sensitivity analyses were performed to compare surgical site infection rates on the basis of actual antibiotics received and for those who had a hysterectomy. Factors independently associated with surgical site infection were identified using a multivariable logistic regression model adjusting for confounding variables.

RESULTS

Of 3343 patients, 2572 (76.9%) and 771 (23.1%) were in the pre-post intervention groups, respectively. Most patients (74.7%) had a hysterectomy performed. Thirty-four percent of cases were for nononcologic (benign) indications. Preintervention patients were more likely to receive appropriate preoperative antibiotics (95.6% vs 90.7%; P<.001). The overall surgical site infection rate before the intervention was 4.7% compared with 2.6% after (P=.010). The surgical site infection rate for all patients who underwent hysterectomy was 4.9% (preintervention) vs 2.8% (postintervention) (P=.036); a similar trend was seen for benign cases (4.4% vs 2.4%; P=.159). On multivariable analysis, the odds ratio for surgical site infection was 0.49 (95% confidence interval, 0.38-0.63) for the postintervention compared with the preintervention group (P<.001). In a sensitivity analysis (n=3087), the surgical site infection rate was 4.5% for those who received cefazolin alone compared with 2.3% for those who received cefazolin plus metronidazole, with significantly decreased odds of surgical site infection for the cefazolin plus metronidazole group (adjusted odds ratio, 0.40 [95% confidence interval, 0.30-0.53]; P<.001). Among only those who had a hysterectomy performed, the odds of surgical site infection were significantly reduced for those in the postintervention group (adjusted odds ratio, 0.63 [95% confidence interval, 0.47-0.86]; P=.003).

CONCLUSION

The addition of metronidazole to cefazolin before gynecologic surgery decreased the surgical site infection rate by half, even after accounting for other known predictors of surgical site infection and differences in practice patterns over time. Providers should consider this combination regimen in women undergoing gynecologic surgery, especially for cases involving hysterectomy.

Bacterial Vaginosis and Post-Operative Pelvic Infections

Bacterial vaginosis (BV) represents a condition in which the normal protective Lactobacilli, especially those that produce H₂O₂, are replaced by high quantities of facultative anaerobes, leading to gynecologic and obstetric post-operative complications. BV is an important cause of obstetric and gynecological adverse sequelae and it could lead to an increased risk of contracting sexually transmitted infections such as gonorrhea, genital herpes, Chlamydia, Trichomonas, and human immunodeficiency virus. Herein, we reviewed bacterial vaginosis and its association with post-operative pelvic infections. In Obstetrics, BV has been associated with increased risk of preterm delivery, first-trimester miscarriage in women undergoing in vitro fertilization, preterm premature rupture of membranes, chorioamnionitis, amniotic fluid infections, postpartum and postabortal endomyometritis as well as postabortal pelvic inflammatory disease (PID). In gynecology, BV increases the risk of post-hysterectomy infections such as vaginal cuff cellulitis, pelvic cellulitis, pelvic abscess, and PID. BV is often asymptomatic, can resolve spontaneously, and often relapses with or without treatment. The American College of Obstetricians and Gynecologists recommends testing for BV in women having an increased risk for preterm delivery. Women with symptoms should be evaluated and treated. Women with BV undergoing gynecological surgeries must be treated to reduce the frequency of post-operative pelvic infections. Metronidazole and clindamycin are the mainstays of therapy. Currently, there is no consensus on pre-surgery screening for BV; decisions are made on a case-by-case basis.

A randomized controlled trial to compare antibiotic prophylaxis in elective gynecological surgeries: Single dose of cefazolin versus single dose of cefazolin and tinidazole

Objectives:

To evaluate if addition of an anti-anaerobic agent to standard drug-cefazolin for antimicrobial prophylaxis would further decrease postoperative infectious morbidity or not. This is relevant as most of the infections in gynecological surgeries are anaerobic but cefazolin does not protect against anaerobes.

Materials and Methods:

The study design was a parallel randomized controlled trial. Two hundred patients undergoing benign gynecological surgeries were divided into two groups of 100 each. Group A received 2 g cefazolin 30–60 min before incision and Group B received 2 g cefazolin 30–60 min and 1.6 g tinidazole 60–120 min before incision. The patients were followed for any infectious morbidity for 1 month postoperatively. The analysis was done separately for abdominal, laparoscopic, and vaginal surgeries. The analysis was also done for surgeries according to the wound category, i.e. clean and clean-contaminated.

Results:

The two groups were comparable for age and body mass index (BMI). The two groups were comparable for the factors affecting infectious morbidity such as duration of surgery, blood loss, blood transfusions, duration of hospital stay, and need for additional antibiotics. The postoperative infectious morbidity was analyzed in terms of fever, surgical site infection (SSI), and urinary tract infection (UTI). No patient in vaginal and laparoscopic groups suffered from infectious morbidity. In abdominal surgeries group, postoperative fever occurred in 6/74 (8.1%) and 11/74 patients (14.8%) in Groups A and B, respectively (P = 0.38). SSI occurred in 1/74 (1.3%) and 2/74 (2.7%) patients in Groups A and B, respectively (P = 1.0). UTI occurred in 5/74 patients (6.7%) and 2/74 patients (2.7%) in Groups A and B, respectively (P = 0.44). The data were also analyzed for infectious morbidity for clean and clean-contaminated wound categories, and the results were nonsignificant between both groups for each type of wound category (P > 0.05).

Conclusion:

Cefazolin alone is a sufficient antibiotic prophylaxis for benign gynecological procedures.

Vaginal preparation with povidone-iodine or chlorhexidine before hysterectomy: a propensity score matched analysis

BACKGROUND

Antiseptic vaginal preparation is recommended before gynecologic surgery; however, there is a lack of data regarding the effectiveness of different agents.

OBJECTIVE

To compare rates of postoperative infectious complications and hospital utilization with preoperative vaginal preparation using povidone-iodine or chlorhexidine before hysterectomy.

STUDY DESIGN

This was a retrospective analysis of patients who underwent hysterectomy for gynecologic indications at 70 hospitals in a statewide surgical collaborative between January 2017 and December 2019. The primary outcome was postoperative infectious complications (including urinary tract infection, surgical site infections involving superficial, deep, or organ space tissues, or cellulitis) within 30 days of surgery. To adjust for confounding, propensity score matching, 1:1 without replacement and with a caliper of.005 was performed to create cohorts that had vaginal preparation with either povidone-iodine or chlorhexidine and did not differ in observable characteristics. We compared the rates of infectious morbidity and hospital utilization (emergency department visits, readmission, reoperation) in the matched cohorts.

RESULTS

In the statewide collaborative, there were 18,184 patients who received povidone-iodine and 3018 who received chlorhexidine. After propensity score matching of 2935 pairs, the povidone-iodine and chlorhexidine groups did not differ in demographics, comorbidities, choice of preoperative antibiotics, benign vs malignant surgical indication, and surgical approach. Povidone-iodine was associated with a lower rate of infectious morbidity (3.0% vs 4.3%; P=.01), urinary tract infection (1.1% vs 1.7%; P=.03) and emergency department visits (7.9% vs 9.7%; P=.01) than with chlorhexidine. There were nonsignificant trends of lower rates of surgical site infection (2.0% vs 2.7%; P=.07) and reoperation (1.6% vs 2.1%; P=.18).

CONCLUSION

This propensity score matched analysis provides evidence that povidone-iodine is preferable to chlorhexidine for vaginal preparation before hysterectomy because of lower rates of infectious morbidity and fewer emergency department visits. However, the absolute differences in infectious morbidity rates were approximately 1%, and in the event of an iodine allergy, chlorhexidine appears to be a reasonable alternative.

Chlorhexidine Versus Iodine for Vaginal Preparation Before Hysterectomy: A Randomized Clinical Trial

OBJECTIVE

The American College of Obstetricians and Gynecologists does not provide a recommendation regarding the preferred vaginal preparation solution. We intended to compare the effectiveness of chlorhexidine versus iodine in decreasing vaginal bacterial counts.

METHODS

In this institutional review board-approved study, participants undergoing total hysterectomy via vaginal or laparoscopic approach were randomized to 4% chlorhexidine or 10% iodine for presurgical vaginal preparation. Swabs were collected from the vaginal mucosa before, then 30, 60, and 90 minutes after preparation. Our primary outcome was the number of positive cultures (≥5,000 bacteria) at 90 minutes. The secondary outcomes included the presence of selected pathogens, postoperative complications, and infections. The sample size of 71 per arm was calculated using P = 0.05, 80% power, and anticipating a 22% difference in positive cultures.

RESULTS

Between May 2018 and August 2019, 85 participants were randomized. The average age was 59.8 years (SD, 11.4), and the median Charlson Comorbidity Index score was 2 (minimum, 0; maximum, 6). Baseline bacterial counts were similar in both groups. Chlorhexidine demonstrated a lower percentage of positive cultures at 90 minutes (47.6% vs 85.4%; odds ratio, 10.6; P = 0.001). In addition, the median bacterial count in the chlorhexidine group was significantly lower than the iodine group (3,000 vs 24,000 colony-forming units, P < 0.001) at 90 minutes. No surgical site infections were identified in either group during the 30-day postoperative period, and there were no reported adverse reactions to either solution.

CONCLUSIONS

Chlorhexidine resulted in substantially lower bacterial counts after preparation compared with iodine. Gynecologic surgeons may consider switching to 4% chlorhexidine for vaginal preparation before hysterectomy.

Gardnerella and vaginal health: the truth is out there

The human vagina is a dynamic ecosystem in which homeostasis depends on mutually beneficial interactions between the host and their microorganisms. However, the vaginal ecosystem can be thrown off balance by a wide variety of factors. Bacterial vaginosis (BV) is the most common vaginal infection in women of childbearing age but its etiology is not yet fully understood, with different controversial theories being raised over the years. What is generally accepted is that BV is often characterized by a shift in the composition of the normal vaginal microbiota, from a Lactobacillus species dominated microbiota to a mixture of anaerobic and facultative anaerobic bacteria. During BV, a polymicrobial biofilm develops in the vaginal microenvironment, being mainly composed of Gardnerella species. The interactions between vaginal microorganisms are thought to play a pivotal role in the shift from health to disease and might also increase the risk of sexually transmitted infections acquisition. Here, we review the current knowledge regarding the specific interactions that occur in the vaginal niche and discuss mechanisms by which these interactions might be mediated. Furthermore, we discuss the importance of novel strategies to fight chronic vaginal infections.

Health care utilization and costs following amplified versus non-amplified molecular probe testing for symptomatic patients with suspected vulvovaginitis: a US commercial payer population

Background

Vulvovaginitis (VV) is a common reason women seek medical attention in the USA. Both the non-specific clinical presentation and risk of preterm labor or delivery necessitate accurate identification of the causative agents to guide appropriate therapy. The diagnostic accuracy of amplified molecular probe testing (AMP) has been shown to exceed that of non-amplified molecular probe (NAMP) by 20%–25%.

Objective

To evaluate the impact of diagnosis with AMP testing on health care utilization, direct costs, and health outcomes, compared with NAMP, for symptomatic patients with suspected VV from a commercial payer perspective.

Methods

Symptomatic women (aged 18–64 years) who underwent VV testing with AMP or NAMP from January 1, 2012–December 31, 2016 were identified using the Truven Health Analytics MarketScan Database; those with continuous medical and pharmacy benefit enrollment 6 months pre/post AMP or NAMP testing were included. Patients were propensity score (PS) matched and 6-month all-cause health care resource utilization, all-cause direct costs (2017 USD), risk of all-cause hospitalization, and risk of preterm labor or delivery were compared between cohorts.

Results

After PS match (N=46,810 per group, mean age 34.2 years), AMP had significantly (all P<0.0001) fewer mean hospital outpatient visits (AMP 0.9 vs NAMP 1.0), primary care physician office visits (AMP 1.1 vs NAMP 1.2), and prescription medications (AMP 7.3 vs NAMP 8.0), and a 21% reduction in risk of hospitalization (risk ratio [RR]=0.79, 95% CI= 0.75–0.83, P<0.0001). Total medical expenditures per patient were lower for AMP than NAMP (mean AMP $3,287 vs NAMP $3,555, P<0.0001). Among pregnant women (N=2,175 per group), AMP had a 12% reduction in risk of preterm labor or delivery (RR =0.88, 95% CI=0.77–0.99, P=0.041).

Conclusion

This real-world study offers evidence on the clinical utility for symptomatic patients with suspected VV diagnosed with AMP compared to NAMP – demonstrating an opportunity to improve the patient journey while delivering value-based care.

Reducing surgical site infections after hysterectomy: metronidazole plus cefazolin compared with cephalosporin alone

BACKGROUND

Organisms that are isolated from vaginal cuff infections and pelvic abscesses after hysterectomy frequently include anaerobic vaginal flora. Metronidazole has outstanding coverage against nearly all anaerobic species, which is superior to both cefazolin and second-generation cephalosporins. Cefazolin plus metronidazole has been demonstrated to reduce infectious morbidity compared with either cefazolin or second-generation cephalosporins in other clean-contaminated procedures, which include both as colorectal surgery and cesarean delivery.

OBJECTIVE

The purpose of this study was to evaluate whether the combination of cefazolin plus metronidazole before hysterectomy was more effective in the prevention of surgical site infection than existing recommendations of cefazolin or second-generation cephalosporin.

STUDY DESIGN

This was a retrospective cohort study of patients in the Michigan Surgical Quality Collaborative from July 2012 through February 2015. The primary outcome was surgical site infection. Patients who were >18 years old and who underwent abdominal, vaginal, laparoscopic, or robotic hysterectomy for benign or malignant indications were included if they received 1 of the following prophylactic antibiotic regimens: cefazolin, second-generation cephalosporin, or cefazolin plus metronidazole. Multivariate logistic regression modeling was performed to evaluate the independent effect of an antibiotic regimen, and propensity score matching was used to validate the findings.

RESULTS

The study included 18,255 hysterectomies. The overall rate of surgical site infection was 1.8% (n=329). The unadjusted rate of surgical site infection was 1.8% (n=267) for cefazolin, 2.1% (n=49) for second-generation cephalosporin, and 1.4% (n=13) for cefazolin plus metronidazole. After adjustment for differences in patient and operative factors among the antibiotic cohorts, compared with cefazolin plus metronidazole, we found the risk of surgical site infection was significantly higher for patients who received cefazolin (odds ratio, 2.30; 95% confidence interval, 1.06-4.99) or second-generation cephalosporin (odds ratio, 2.31; 95% confidence interval, 1.21-4.41).

CONCLUSION

In this large cohort, the use of prophylactic cefazolin plus metronidazole resulted in lower surgical site infection rates after hysterectomy compared with cefazolin or second-generation cephalosporin.

Susceptibility of Gardnerella vaginalis biofilms to natural antimicrobials subtilosin, ε-poly-L-lysine, and lauramide arginine ethyl ester

Bacterial vaginosis is a common vaginal infection associated with numerous gynecological and obstetric complications. This condition is characterized by the presence of thick adherent vaginal biofilms, composed mainly of Gardnerella vaginalis. This organism is thought to be the primary aetiological cause of the infection paving the way for various opportunists to colonize the niche. Previously, we reported that the natural antimicrobials subtilosin, ε-poly-L-lysine, and lauramide arginine ethyl ester selectively inhibit the growth of this pathogen. In this study, we used plate counts to evaluate the efficacy of these antimicrobials against established biofilms of G. vaginalis. Additionally, we validated and compared two rapid methods (ATP viability and resazurin assays) for the assessment of cell viability in the antimicrobial-treated G. vaginalis biofilms. Out of the tested antimicrobials, lauramide arginine ethyl ester had the strongest bactericidal effect, followed by subtilosin, with clindamycin and polylysine showing the weakest effect. In comparison to plate counts, ATP viability and resazurin assays considerably underestimated the bactericidal effect of some antimicrobials. Our results indicate that these assays should be validated for every new application.

The natural antimicrobial peptide subtilosin acts synergistically with glycerol monolaurate, lauric arginate, and ε-poly-L-lysine against bacterial vaginosis-associated pathogens but not human lactobacilli

Subtilosin is a cyclical antimicrobial peptide produced by Bacillus amyloliquefaciens that has antimicrobial activity against the bacterial vaginosis-associated human pathogen Gardnerella vaginalis. The ability of subtilosin to inhibit G. vaginalis alone and in combination with the natural antimicrobial agents glycerol monolaurate (Lauricidin), lauric arginate, and ε-poly-L-lysine was tested using a checkerboard approach. Subtilosin was found to act synergistically with all of the chosen antimicrobials. These promising results indicate that lower concentrations of subtilosin in combination with other compounds could effectively be used to inhibit growth of the pathogen, thereby decreasing the risk of developed antimicrobial resistance. This is the first report on the effects of subtilosin combined with other natural antimicrobials against G. vaginalis.

The aetiology of bacterial vaginosis

Bacterial vaginosis (BV) is the most common vaginal infection among women of childbearing age. This condition is notorious for causing severe complications related to the reproductive health of women. Five decades of intense research established many risk factors for acquisition of BV; however, because of the complexity of BV and lack of a reliable animal model for this condition, its exact aetiology remains elusive. In this manuscript, we use a historical perspective to critically review the development of major theories on the aetiology of BV, ultimately implicating BV-related pathogens, healthy vaginal microbiota, bacteriophages and the immune response of the host. None of these theories on their own can reliably explain the epidemiological data. Instead, BV is caused by a complex interaction of multiple factors, which include the numerous components of the vaginal microbial ecosystem and their human host. Many of these factors are yet to be characterized because a clear understanding of their relative contribution to the aetiology of BV is pivotal to the formulation of an effective treatment for and prophylaxis of this condition.

Elucidation of the Molecular Mechanisms of Action of the Natural Antimicrobial Peptide Subtilosin Against the Bacterial Vaginosis-associated Pathogen Gardnerella vaginalis

Subtilosin A is a 35-amino acid long cyclical peptide produced by Bacillus amyloliquefaciens that has potent antimicrobial activity against a variety of human pathogens, including the bacterial vaginosis-related Gardnerella vaginalis. The specific mode of action of subtilosin against G. vaginalis was elucidated by studying its effects on the proton motive force's (PMF) components: transmembrane electric potential (ΔΨ), transmembrane pH gradient (ΔpH), and intracellular ATP levels. The addition of subtilosin to G. vaginalis cells caused an immediate and total depletion of the ΔpH, but had no effect on the ΔΨ. Subtilosin also triggered an instant but partial efflux of intracellular ATP that was twofold higher than that of the positive control bacteriocin, nisin. Taken together, these data suggest that subtilosin inhibits G. vaginalis growth by creating transient pores in the cells' cytoplasmic membrane, leading to an efflux of intracellular ions and ATP and eventually cell death.

Screening for group B streptococcus: a private hospital's experience

OBJECTIVE

To assess the effect of universal screening and administration of intrapartum antibiotic prophylaxis to prevent early-onset neonatal GBS sepsis at a private tertiary care hospital since issuance of the 2002 CDC guidelines for preventing perinatal GBS disease.

METHODS

Retrospective analysis of women delivering between January 1, 2003 and December 31, 2004 at a private tertiary care hospital in Houston, Texas. The percentage of women screened, GBS positive women receiving intrapartum antibiotic prophylaxis, and infants developing early-onset GBS sepsis were determined.

RESULTS

2,108 women delivered 2,135 infants with 1,874 (89%) screened for GBS. Of those screened, 1,322 (71%) tested negative and 552 (29%) tested positive for GBS. In this analysis of 2,135 infants, 3 (0.94 cases/1,000 live births) were diagnosed with invasive GBS sepsis.

CONCLUSION

High rates of screening of pregnant women for GBS colonization and use of intrapartum antibiotic prophylaxis for GBS carriers can be achieved in a private tertiary care hospital setting. "

SYNOPSIS

High screening rates for group B streptococcus in a private tertiary care hospital reduce the incidence of maternal and early onset neonatal GBS infection."

[Bacterial vaginosis]

Bacterial vaginosis is a widely spread health problem with multiple connotations. It has been the subject of many studies and work during decades and it still remains a polemic entity, with contradictory finding. The polymicrobian etiology, unsolved epidemiology, obstetrico-gynecological complications and high recurrence rate following treatment, make this infection a target for researchers. It is not an inflammatory process -yet an immune response exists. In this disorder, vaginal discharge increases, and it is associated with a high risk of developing sexually transmitted diseases.

Postoperative pelvic infections

Infectious morbidity affecting the postoperative course has long been a concern for obstetricians and gynecologists. The incidence of postoperative infections approaches 38%. The third most common nosocomial infection is surgical site infection. The realm of postoperative infections includes obstetric and gynecologic sources. An understanding of the basic fundamentals of the vaginal flora and addressing host and surgical risk factors can aid in prevention of postoperative infections, which result in significant morbidity and mortality.

Bacterial vaginosis: an overview for 2009

Bacterial vaginosis has been appreciated as a unique clinical entity for well over 50 years. Its essential manifestations are well established: a loss of the normal bacterial population of the vagina and their replacement by other species. Investigations into this condition have led to a better understanding of its prevalence and epidemiology. Microbiologic and biochemical studies have exposed the remarkably complex pathophysiologic events that occur with bacterial vaginosis. Several major morbidities accompany this condition. Advances have been made in treatment, including the recent availability of a new therapeutic agent, tinidazole. However, the root cause of the condition is elusive, and as a result managing bacterial vaginosis and its complications is unsatisfactory; moreover, data suggest that therapy now is less successful than in the past. This article brings together the current fund of knowledge about bacterial vaginosis in a way that offers clinicians a realistic view of our capabilities and concerns.

Spermicidal activity of the safe natural antimicrobial peptide subtilosin

Bacterial vaginosis (BV), a condition affecting millions of women each year, is primarily caused by the gram-variable organism Gardnerella vaginalis. A number of organisms associated with BV cases have been reported to develop multidrug resistance, leading to the need for alternative therapies. Previously, we reported the antimicrobial peptide subtilosin has proven antimicrobial activity against G. vaginalis, but not against the tested healthy vaginal microbiota of lactobacilli. After conducting tissue sensitivity assays using an ectocervical tissue model, we determined that human cells remained viable after prolonged exposures to partially-purified subtilosin, indicating the compound is safe for human use. Subtilosin was shown to eliminate the motility and forward progression of human spermatozoa in a dose-dependent manner, and can therefore be considered a general spermicidal agent. These results suggest subtilosin would be a valuable component in topical personal care products aimed at contraception and BV prophylaxis and treatment.

Bacterial vaginosis. Transmission, role in genital tract infection and pregnancy outcome: an enigma

Whether bacterial vaginosis (BV) is acquired from an endogenous or an exogenous source is subject to controversy. Despite findings of an association between sexual behaviour and BV, some data indicate that BV is not a sexually transmitted infection in the traditional sense, while other data indicate that BV is an exogenous infection. A third aspect of BV is its tendency to go unnoticed by affected women. All of this will have a strong impact on how physicians view the risks of asymptomatic BV. This review focuses on whether or not BV should be regarded as a sexually transmitted infection (STI), its role in postoperative infections and pelvic inflammatory disease (PID), and on whether or not treatment of BV during pregnancy to reduce preterm delivery should be recommended. The reviewed studies do not lend unequivocal support to an endogenous or exogenous transmission of the bacteria present in BV. For women undergoing gynaecological surgery such as therapeutic abortion, the relative risk of postoperative infection is clearly elevated (approx. 2.3-2.8). A weaker association exists between BV and pelvic inflammatory disease. Data on treatment of BV as a way of reducing preterm delivery are inconclusive and do not support recommendations for general treatment of BV during pregnancy. The discrepant associations between BV and preterm birth found in recent studies may be explained by variations in immunological response to BV. Genetic polymorphism in the cytokine response--both regarding the TNF alleles and in interleukin production--could make women more or less susceptible to BV, causing different risks of preterm birth. Thus, studies on the vaginal inflammatory response to microbial colonization should be given priority.

Evaluation of clinical methods for diagnosing bacterial vaginosis

OBJECTIVE

To determine whether the current clinical criteria for diagnosing bacterial vaginosis can be simplified by using 2 clinical criteria rather than the standard 3 of 4 criteria (Amsel's criteria).

METHODS

This was a prospective observational study of 269 women undergoing a vaginal examination in the Women's Primary Care Center, Division of Research, or Colposcopy Clinic at Women & Infants Hospital. All 4 clinical criteria for diagnosing bacterial vaginosis were collected, and Gram stain was used as the gold standard. Sensitivity and specificity were calculated for each individual criterion, combinations of criteria, and a colorimetric pH and amine card. Receiver operating characteristic curve was generated to estimate the preferred pH and percentage of clue cells for diagnosing bacterial vaginosis.

RESULTS

The prevalence of bacterial vaginosis in our study population was 38.7%. Vaginal pH was the most sensitive of all the criteria, at 89%, and a positive amine odor was the individual criteria with the highest specificity, at 93%. Similar specificity was seen with combinations of 2 criteria and Amsel's criteria. Receiver operating characteristic curve analysis yielded a preferred pH and percentage of clue cells of 5.0 and 20%, respectively. However, a pH of 4.5 or greater improves sensitivity with minimal loss of specificity.

CONCLUSION

The clinical criteria for diagnosing bacterial vaginosis can be simplified to 2 clinical criteria without loss of sensitivity and specificity.

Antibiotic resistance patterns of group B streptococcal clinical isolates

OBJECTIVES: To determine the in vitro resistance of group B streptococcus (GBS) to 12 antibiotics. To determine if there has been any decrease in sensitivity to the penicillins or other antibiotics currently used for GBS chemoprophylaxis in pregnant women. Find suitable alternative antibiotics to penicillin. Find an antibiotic that will have minimal selective pressure for resistance among the endogenous resident vaginal microflora. METHODS: The antibiotic susceptibility profiles of 52 clinical isolates of GBS were evaluated to 12 antibiotics: ampicillin, azithromycin, cefamandole, cefazolin, ceftriaxone, ciprofloxacin, clindamycin, erythromycin, nitrofurantoin, ofloxacin, penicillin and vancomycin. Antibiotic sensitivities were determined using disk diffusion and microdilution methods according to the guidelines of the National Committee for Clinical Laboratory Standards (NCCLS). RESULTS: All isolates were sensitive to vancomycin, ofloxacin, ampicillin, ciprofloxacin, nitrofurantoin and penicillin. However, the following number of clinical isolates exhibited intermediate or decreased sensitivity, nine (17%) to ampicillin, eight (15%) to penicillin, 14 (32%) to ciprofloxacin and one (2%) to nitrofurantoin. Thirty-one percent of the isolates were resistant to azithromycin and ceftriaxone, 19% to clindamycin, 15% to cefazolin and 13% to cefamandole. Eighteen (35%) of the clinical isolates tested were resistant to 6 of the 12 antibiotics tested. CONCLUSIONS: The relatively high rates of resistance for 6 of the 12 antibiotics tested suggest that for women allergic to penicillin and colonized with GBS, antibiotic sensitivities to their isolates should be determined. The antibiotic selected for intrapartum chemoprophylaxis should be guided by the organism's antibiotic sensitivity pattern. Patients with GBS bacteriuria should be treated with nitrofurantoin.

Does pre- and postoperative metronidazole treatment lower vaginal cuff infection rate after abdominal hysterectomy among women with bacterial vaginosis?

OBJECTIVE

Bacterial vaginosis (BV) is a known risk factor for postoperative infection following abdominal hysterectomy. Vaginal bacterial flora scored as intermediate has been shown to have the same risk of postoperative infection as BV.

METHODS

Women undergoing total abdominal hysterectomy for benign diseases were open-randomized according to Zelen to either treatment with metronidazole rectally for at least 4 days or no treatment. At the preoperative gynecological examination a vaginal smear was collected and Gram stained. Women with BV or intermediate flora were merged to one group called abnormal vaginal flora.

RESULTS

In total 213 women were randomized to treatment or no treatment. After exclusion of 71 women, 142 women were eligible for analysis. Among the 59 women diagnosed with abnormal vaginal flora there were no vaginal cuff infections in the treated arm, compared with 27% in the 'no treatment' arm (p < 0.01). Treatment also reduced the vaginal cuff infection rate from 9.5 to 2% among the 83 women with lactobacilli flora. However, this difference was not statistically significant. Treatment had no effect on the rate of wound infections. Intention-to-treat analysis showed a significant reduction in vaginal cuff infections among women randomized to treatment.

CONCLUSION

Pre- and postoperative treatment for at least 4 days with metronidazole rectally reduces significantly vaginal cuff infection among women with abnormal vaginal flora.

Gardnerella vaginalis isolated from patients with bacterial vaginosis and from patients with healthy vaginal ecosystems

The differences in the phenotype and genotype of Gardnerella vaginalis isolates from patients with bacterial vaginosis (BV) and from patients without BV are unknown. In our study, 43 isolates of G. vaginalis were examined for biotype (hippurate hydrolysis, lipase, and beta-galactosidase activity), sensitivity to metronidazole, and genotype. Of the 117 women visiting the gynecology clinic at Rush-Presbyterian-St. Luke's Medical Center who were included in the study, 27.4% were found to have BV. G. vaginalis was found in samples from 87.5% of women with BV, from 34.0% of women with intermediate BV, and from 26.4% of women with healthy vaginal ecosystems. Among patients with G. vaginalis, biotypes 7 and 8 were isolated from 32% and 20% of patients, respectively. Biotype 5 was predominantly associated with a healthy vaginal ecosystem (P=.0004). Biotypes 5 and 7 were the most resistant to metronidazole. No specific phenotype or genotype of G. vaginalis causes BV.

Gynecologic conditions and bacterial vaginosis: implications for the non-pregnant patient

Bacterial vaginosis is characterized by a shift from the predominant lactobacillus vaginal flora to an overgrowth of anaerobic bacteria. Bacterial vaginosis is associated with an increased risk of gynecologic complications, including pelvic inflammatory disease, postoperative infection, cervicitis, human immunodeficiency virus (HIV), and possibly cervical intraepithelial neoplasia (CIN). The obstetrical risks associated with bacterial vaginosis include premature rupture of membranes, preterm labor and delivery, chorioamnionitis and postpartum endometritis. Despite the health risks associated with bacterial vaginosis and its high prevalence in women of childbearing age, bacterial vaginosis continues to be largely ignored by clinicians, particularly in asymptomatic women.