A prospective randomized trial of imipenem-cilastatin versus clindamycin/tobramycin in the treatment of intra-abdominal and pelvic infections

Antibiotic therapy for pelvic inflammatory disease

BACKGROUND

Pelvic inflammatory disease (PID) affects 4% to 12% of women of reproductive age. The main intervention for acute PID is broad-spectrum antibiotics administered intravenously, intramuscularly or orally. We assessed the optimal treatment regimen for PID.  OBJECTIVES: To assess the effectiveness and safety of antibiotic regimens to treat PID.

SEARCH METHODS

In January 2020, we searched the Cochrane Sexually Transmitted Infections Review Group's Specialized Register, which included randomized controlled trials (RCTs) from 1944 to 2020, located through hand and electronic searching; CENTRAL; MEDLINE; Embase; four other databases; and abstracts in selected publications.

SELECTION CRITERIA

We included RCTs comparing antibiotics with placebo or other antibiotics for the treatment of PID in women of reproductive age, either as inpatient or outpatient treatment. We limited our review to a comparison of drugs in current use that are recommended by the 2015 US Centers for Disease Control and Prevention guidelines for treatment of PID.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane. Two authors independently extracted data, assessed risk of bias and conducted GRADE assessments of the quality of evidence.

MAIN RESULTS

We included 39 RCTs (6894 women) in this review, adding two new RCTs at this update. The quality of the evidence ranged from very low to high, the main limitations being serious risk of bias (due to poor reporting of study methods and lack of blinding), serious inconsistency, and serious imprecision. None of the studies reported quinolones and cephalosporins, or the outcomes laparoscopic evidence of resolution of PID based on physician opinion or fertility outcomes. Length of stay results were insufficiently reported for analysis. Regimens containing azithromycin versus regimens containing doxycycline We are uncertain whether there was a clinically relevant difference between azithromycin and doxycycline in rates of cure for mild-moderate PID (RR 1.18, 95% CI 0.89 to 1.55; 2 RCTs, 243 women; I² = 72%; very low-quality evidence). The analyses may result in little or no difference between azithromycin and doxycycline in rates of severe PID (RR 1.00, 95% CI 0.96 to 1.05; 1 RCT, 309 women; low-quality evidence), or adverse effects leading to discontinuation of treatment (RR 0.71, 95% CI 0.38 to 1.34; 3 RCTs, 552 women; I² = 0%; low-quality evidence). In a sensitivity analysis limited to a single study at low risk of bias, azithromycin probably improves the rates of cure in mild-moderate PID (RR 1.35, 95% CI 1.10 to 1.67; 133 women; moderate-quality evidence), compared to doxycycline.  Regimens containing quinolone versus regimens containing cephalosporin The analysis shows there may be little or no clinically relevant difference between quinolones and cephalosporins in rates of cure for mild-moderate PID (RR 1.05, 95% CI 0.98 to 1.14; 4 RCTs, 772 women; I² = 15%; low-quality evidence), or severe PID (RR 1.06, 95% CI 0.91 to 1.23; 2 RCTs, 313 women; I² = 7%; low-quality evidence). We are uncertain whether there was a difference between quinolones and cephalosporins in adverse effects leading to discontinuation of treatment (RR 2.24, 95% CI 0.52 to 9.72; 6 RCTs, 1085 women; I² =  0%; very low-quality evidence). Regimens with nitroimidazole versus regimens without nitroimidazole There was probably little or no difference between regimens with or without nitroimidazoles (metronidazole) in rates of cure for mild-moderate PID (RR 1.02, 95% CI 0.95 to 1.09; 6 RCTs, 2660 women; I² = 50%; moderate-quality evidence), or severe PID (RR 0.96, 95% CI 0.92 to 1.01; 11 RCTs, 1383 women; I² = 0%; moderate-quality evidence). The evidence suggests that there was little to no difference in in adverse effects leading to discontinuation of treatment (RR 1.05, 95% CI 0.69 to 1.61; 17 studies, 4021 women; I² = 0%; low-quality evidence). . In a sensitivity analysis limited to studies at low risk of bias, there was little or no difference for rates of cure in mild-moderate PID (RR 1.05, 95% CI 1.00 to 1.12; 3 RCTs, 1434 women; I² = 0%; high-quality evidence). Regimens containing clindamycin plus aminoglycoside versus quinolone We are uncertain whether quinolone have little to no effect in  rates of cure for mild-moderate PID compared to clindamycin plus aminoglycoside (RR 0.88, 95% CI 0.69 to 1.13; 1 RCT, 25 women; very low-quality evidence). The analysis may result in little or no difference between quinolone vs. clindamycin plus aminoglycoside in severe PID (RR 1.02, 95% CI 0.87 to 1.19; 2 studies, 151 women; I² =  0%; low-quality evidence). We are uncertain whether quinolone reduces adverse effects leading to discontinuation of treatment (RR 0.21, 95% CI 0.02 to 1.72; 3 RCTs, 163 women; I² =  0%; very low-quality evidence). Regimens containing clindamycin plus aminoglycoside versus regimens containing cephalosporin We are uncertain whether clindamycin plus aminoglycoside improves the rates of cure for mild-moderate PID compared to cephalosporin (RR 1.02, 95% CI 0.95 to 1.09; 2 RCTs, 150 women; I² =  0%; low-quality evidence). There was probably little or no difference in rates of cure in severe PID with clindamycin plus aminoglycoside compared to cephalosporin (RR 1.00, 95% CI 0.95 to 1.06; 10 RCTs, 959 women; I²= 21%; moderate-quality evidence). We are uncertain whether clindamycin plus aminoglycoside reduces adverse effects leading to discontinuation of treatment compared to cephalosporin (RR 0.78, 95% CI 0.18 to 3.42; 10 RCTs, 1172 women; I² =  0%; very low-quality evidence).

AUTHORS' CONCLUSIONS

We are uncertain whether one treatment was safer or more effective than any other for the cure of mild-moderate or severe PID Based on a single study at a low risk of bias, a macrolide (azithromycin) probably improves the rates of cure of mild-moderate PID, compared to tetracycline (doxycycline).

Antibiotic therapy for pelvic inflammatory disease

BACKGROUND

Pelvic inflammatory disease (PID) is an infection that affects 4% to 12% of young women, and is one of the most common causes of morbidity in this age group. The main intervention for acute PID is the use of broad-spectrum antibiotics which cover Chlamydia trachomatis, Neisseria gonorrhoeae, and anaerobic bacteria, administered intravenously, intramuscularly, or orally. In this review, we assessed the optimal treatment regimen for PID.

OBJECTIVES

To assess the effectiveness and safety of antibiotic regimens used to treat pelvic inflammatory disease.

SEARCH METHODS

We searched the Cochrane Sexually Transmitted Infections Review Group's Specialized Register, which included randomized controlled trials (RCTs) from 1944 to 2016, located through electronic searching and handsearching; the Cochrane Central Register of Controlled Trials (CENTRAL), Ovid platform (1991 to July 2016); MEDLINE (1946 to July 2016); Embase (1947 to July 2016); LILACS, iAHx interface (1982 to July 2016); World Health Organization International Clinical Trials Registry Platform (July 2016); Web of Science (2001 to July 2016); OpenGrey (1990, 1992, 1995, 1996, and 1997); and abstracts in selected publications.

SELECTION CRITERIA

We included RCTs comparing the use of antibiotics with placebo or other antibiotics for the treatment of PID in women of reproductive age, either as inpatient or outpatient treatment. We limited our review to comparison of drugs in current use that are recommended for consideration by the 2015 US Centers for Disease Control and Prevention (CDC) guidelines for treatment of PID.

DATA COLLECTION AND ANALYSIS

At least two review authors independently selected trials for inclusion, extracted data, and assessed risk of bias. We contacted investigators to obtain missing information. We resolved disagreements by consensus or by consulting a fourth review author if necessary. We assessed the quality of the evidence using GRADE criteria, classifying it as high, moderate, low, or very low. We calculated Mantel-Haenszel risk ratios (RR), using either random-effects or fixed-effect models and number needed to treat for an additional beneficial outcome or for an additional harmful outcome, with their 95% confidence interval (CI), to measure the effect of the treatments. We conducted sensitivity analyses limited to studies at low risk of bias, for comparisons where such studies were available.

MAIN RESULTS

We included 37 RCTs (6348 women). The quality of the evidence ranged from very low to high, the main limitations being serious risk of bias (due to poor reporting of study methods and lack of blinding), serious inconsistency, and serious imprecision. Azithromycin versus doxycyclineThere was no clear evidence of a difference between the two drugs in rates of cure for mild-moderate PID (RR 1.18, 95% CI 0.89 to 1.55, I² = 72%, 2 RCTs, 243 women, very low-quality evidence), severe PID (RR 1.00, 95% CI 0.96 to 1.05, 1 RCT, 309 women, low-quality evidence), or adverse effects leading to discontinuation of treatment (RR 0.71, 95% CI 0.38 to 1.34, 3 RCTs, 552 women, I² = 0%, low-quality evidence). In a sensitivity analysis limited to a single study at low risk of bias, azithromycin was superior to doxycycline in achieving cure in mild-moderate PID (RR 1.35, 95% CI 1.10 to 1.67, 133 women, moderate-quality evidence). Quinolone versus cephalosporinThere was no clear evidence of a difference between the two drugs in rates of cure for mild-moderate PID (RR 1.04, 95% CI 0.98 to 1.10, 3 RCTs, 459 women, I² = 5%, low-quality evidence), severe PID (RR 1.06, 95% CI 0.91 to 1.23, 2 RCTs, 313 women, I² = 7%, low-quality evidence), or adverse effects leading to discontinuation of treatment (RR 2.24, 95% CI 0.52 to 9.72, 5 RCTs, 772 women, I² = 0%, very low-quality evidence). Nitroimidazole versus no use of nitroimidazoleThere was no conclusive evidence of a difference between the nitroimidazoles (metronidazole) group and the group receiving other drugs with activity over anaerobes (e.g. amoxicillin-clavulanate) in rates of cure for mild-moderate PID (RR 1.01, 95% CI 0.93 to 1.10, 5 RCTs, 2427 women, I² = 60%, moderate-quality evidence), severe PID (RR 0.96, 95% CI 0.92 to 1.01, 11 RCTs, 1383 women, I² = 0%, moderate-quality evidence), or adverse effects leading to discontinuation of treatment (RR 1.00, 95% CI 0.63 to 1.59; participants = 3788; studies = 16; I² = 0% , low-quality evidence). In a sensitivity analysis limited to studies at low risk of bias, findings did not differ substantially from the main analysis (RR 1.06, 95% CI 0.98 to 1.15, 2 RCTs, 1201 women, I² = 32%, high-quality evidence). Clindamycin plus aminoglycoside versus quinoloneThere was no evidence of a difference between the two groups in rates of cure for mild-moderate PID (RR 0.88, 95% CI 0.69 to 1.13, 1 RCT, 25 women, very low-quality evidence), severe PID (RR 1.02, 95% CI 0.87 to 1.19, 2 studies, 151 women, I² = 0%, low-quality evidence), or adverse effects leading to discontinuation of treatment (RR 0.21, 95% CI 0.02 to 1.72, 3 RCTs, 163 women, very low-quality evidence). Clindamycin plus aminoglycoside versus cephalosporinThere was no clear evidence of a difference between the two groups in rates of cure for mild-moderate PID (RR 1.02, 95% CI 0.95 to 1.09, 2 RCTs, 150 women, I² = 0%, low-quality evidence), severe PID (RR 1.00, 95% CI 0.95 to 1.06, 10 RCTs, 959 women, I² = 21%, moderate-quality evidence), or adverse effects leading to discontinuation of treatment (RR 0.78, 95% CI 0.18 to 3.42, 10 RCTs, 1172 women, I² = 0%, very low-quality evidence).

AUTHORS' CONCLUSIONS

We found no conclusive evidence that one regimen of antibiotics was safer or more effective than any other for the cure of PID, and there was no clear evidence for the use of nitroimidazoles (metronidazole) compared to use of other drugs with activity over anaerobes. Moderate-quality evidence from a single study at low risk of bias suggested that a macrolide (azithromycin) may be more effective than a tetracycline (doxycycline) for curing mild-moderate PID. Our review considered only the drugs that are currently used and mentioned by the CDC.

Empiric Treatment of Nosocomial Intra-Abdominal Infections: A Focus on the Carbapenems

BACKGROUND

Serious nosocomial intra-abdominal infections are associated with high morbidity and mortality and represent a substantial drain on healthcare resources. Effective management of this type of infection requires the early use of appropriate, broad-spectrum empiric antimicrobial therapy. The consequences of delayed or inappropriate antimicrobial treatment can be severe-leading to an increased risk of death, re-operation, or prolonged hospitalization. Therefore, it is necessary to begin treatment as soon as possible with the most appropriate regimen, in terms of spectrum, timing, and duration.

METHODS

Review of pertinent English-language literature.

RESULTS

Serious nosocomial intra-abdominal infections require broad-spectrum coverage because of the wide range of possible pathogens, which include difficult-to-treat organisms such as Pseudomonas aeruginosa and Bacteroides spp., and resistant strains of Klebsiella spp., Escherichia coli, and methicillin-resistant Staphylococcus aureus acquired from the hospital flora. The early use of appropriate, broad-spectrum empiric antimicrobial therapy for treating high-risk patients with intra-abdominal infections is considered, and appropriate use of the carbapenems, meropenem, and imipenem/cilastatin, is described.

CONCLUSION

The carbapenems meropenem and imipenem/cilastatin have a spectrum of antimicrobial activity that covers the majority of expected pathogens, including anaerobes, as well as difficult-to-treat and resistant gram-negative strains. Early and appropriate use can reduce mortality and morbidity. Data from published clinical trials support the clinical effectiveness of these two carbapenems in intra-abdominal infections.

Meropenem versus imipenem/cilastatin as empirical monotherapy for serious bacterial infections in the intensive care unit

OBJECTIVE

To compare the efficacy and tolerability of meropenem and imipenem/cilastatin as empirical monotherapy in intensive care unit (ICU) patients with serious bacterial infections.

METHODS

A multicenter, open-label, randomized, parallel-group trial was conducted in Belgium, evaluating empirical monotherapy with meropenem or imipenem/cilastatin (both 1 g/8 h intravenously) in ICU patients with one or more of the following infections caused by sensitive pathogens: lower respiratory tract infection (LRTI) in ventilated patients, intra-abdominal infection or sepsis.

RESULTS

The overall satisfactory clinical response rate at the end of randomized treatment was 77.0% (67/87) with meropenem and 68.1% (62/91) with imipenem/cilastatin (difference 8.9%; 95% confidence interval -4.2% to 21.9%; P = 0.185). The two drugs produced similar satisfactory clinical response rates against LRTIs: 68.3% (41/60) with meropenem versus 68.6% (35/51) with imipenem/cilastatin. Meropenem appeared to be slightly more effective against intra-abdominal infections: 95.5% (21/22) versus 76.7% (23/30), respectively. All five meropenem recipients with sepsis had a satisfactory clinical response, compared to 40.0% (4/10) of those who received imipenem/cilastatin. The overall satisfactory bacteriologic response rate was 67.1% (49/73) with meropenem and 60.3% (44/73) with imipenem/cilastatin (difference 6.9%; 95% confidence interval -8.7% to 22.4%; P = 0.389). The predominant pathogens were Escherichia coli, Enterobacter spp. and Pseudomonas aeruginosa. No incidences of drug-related nausea and vomiting were reported, but one probable drug-related seizure occurred in the imipenem/cilastatin group.

CONCLUSIONS

Meropenem is at least as efficacious (clinically and bacteriologically) as imipenem/cilastatin for the empirical monotherapy of serious bacterial infections in ICU patients, and it can therefore be considered a useful option in this setting. Moreover, meropenem is well tolerated and offers several potential advantages, including greater in vitro activity against Gram-negative pathogens and the option of bolus administration.

Carbapenems and monobactams: imipenem, meropenem, and aztreonam

Imipenem and meropenem, members of the carbapenem class of beta-lactam antibiotics, are among the most broadly active antibiotics available for systemic use in humans. They are active against streptococci, methicillin-sensitive staphylococci, Neisseria, Haemophilus, anaerobes, and the common aerobic gram-negative nosocomial pathogens including Pseudomonas. Resistance to imipenem and meropenem may emerge during treatment of P. aeruginosa infections, as has occurred with other beta-lactam agents; Stenotrophomonas maltophilia is typically resistant to both imipenem and meropenem. Like the penicillins, the carbapenems have inhibitory activity against enterococci. In general, the in vitro activity of imipenem against aerobic gram-positive cocci is somewhat greater than that of meropenem, whereas the in vitro activity of meropenem against aerobic gram-negative bacilli is somewhat greater than that of imipenem. Daily dosages may range from 0.5 to 1 g every 6 to 8 hours in patients with normal renal function; the daily dose of meropenem, however, can be safely increased to 6 g. Infusion-related nausea and vomiting, as well as seizures, which have been the main toxic effects of imipenem, occur no more frequently during treatment with meropenem than during treatment with other beta-lactam antibiotics. The carbapenems should be considered for treatment of mixed bacterial infections and aerobic gram-negative bacteria that are not susceptible to other beta-lactam agents. Indiscriminate use of these drugs will promote resistance to them. Aztreonam, the first marketed monobactam, has activity against most aerobic gram-negative bacilli including P. aeruginosa. The drug is not nephrotoxic, is weakly immunogenic, and has not been associated with disorders of coagulation. Aztreonam may be administered intramuscularly or intravenously; the primary route of elimination is urinary excretion. In patients with normal renal function, the recommended dosing interval is every 8 hours. Patients with renal impairment require dosage adjustment. Aztreonam is used primarily as an alternative to aminoglycosides and for the treatment of aerobic gram-negative infections. It is often used in combination therapy for mixed aerobic and anaerobic infections. Approved indications for its use include infections of the urinary tract or lower respiratory tract, intra-abdominal and gynecologic infections, septicemia, and cutaneous infections caused by susceptible organisms. Concurrent initial therapy with other antimicrobial agents is recommended before the causative organism has been determined in patients who are seriously ill or at risk for gram-positive or anaerobic infection.

Meropenem (1.5 g/day) is as effective as imipenem/cilastatin (2 g/day) for the treatment of moderately severe intra-abdominal infections

This multicentre, open-label, randomised trial compared meropenem (0.5 g/8 h) and imipenem/cilastatin (at the commonly used dosage of 0.5 g/6 h) in monotherapy in patients with moderately severe intra-abdominal infections (IAIs). In total, 161 patients were randomised (82 meropenem, 79 imipenem/cilastatin). The mean APACHE II scores in the two groups were 5.8 and 6.4, respectively. At the end of therapy, 65/71 (91.6%) evaluable meropenem recipients were clinically cured or improved, compared to 60/64 (93.8%) imipenem/cilastatin recipients. This difference and that in an intention-to-treat analysis (82.1 vs 86.1%, respectively), were not statistically significant. Both drugs were generally well tolerated. Thus, meropenem 0.5 g/8 h is as clinically effective and well tolerated as imipenem/cilastatin 0.5 g/6 h in moderately severe IAIs.

Imipenem/cilastatin: an update of its antibacterial activity, pharmacokinetics and therapeutic efficacy in the treatment of serious infections

The prototype carbapenem antibacterial agent imipenem has a very broad spectrum of antibacterial activity, encompassing most Gram-negative and Gram-positive aerobes and anaerobes, including most beta-lactamase-producing species. It is coadministered with a renal dehydropeptidase inhibitor, cilastatin, in order to prevent its renal metabolism in clinical use. Extensive clinical experience gained with imipenem/cilastatin has shown it to provide effective monotherapy for septicaemia, neutropenic fever, and intra-abdominal, lower respiratory tract, genitourinary, gynaecological, skin and soft tissues, and bone and joint infections. In these indications, imipenem/cilastatin generally exhibits similar efficacy to broad-spectrum cephalosporins and other carbapenems and is at least equivalent to standard aminoglycoside-based and other combination regimens. Imipenem/cilastatin is generally well tolerated by adults and children, with local injection site events, gastrointestinal disturbances and dermatological reactions being the most common adverse events. Seizures have also been reported, occurring mostly in patients with impaired renal function or CNS pathology, or with excessive dosage. Although it is no longer a unique compound, as newer carbapenems such as meropenem are becoming available, imipenem/cilastatin nevertheless remains an important agent with established efficacy as monotherapy for moderate to severe bacterial infections. Its particular niche is in treating infections known or suspected to be caused by multiresistant pathogens.