Resistance to third-generation cephalosporins in adult gram-negative bacillary meningitis

Epidemiology and antimicrobial resistance patterns of bacterial meningitis among hospitalized patients at a tertiary care hospital in Saudi Arabia: a six-year retrospective study

INTRODUCTION

Bacterial meningitis poses significant medical challenges due to its acute inflammatory nature and potential for severe neurological complications, emphasizing the need for prompt diagnosis and treatment. Limited data exists on its epidemiology and antimicrobial resistance trends among hospitalized patients in Saudi Arabia. This study aimed to investigate these factors at a tertiary care hospital over six years.

METHODS

A retrospective analysis was conducted on cerebrospinal fluid samples results from 222 bacterial meningitis cases among hospitalized patients between 2018 and 2023. Demographic, clinical, microbiological data, and antibiotic susceptibility patterns were collected and analyzed.

RESULTS

Pseudomonas aeruginosa (43%) was the predominant pathogen isolated. Neonates (16%) and children (47%) were most affected population. Nosocomial meningitis accounted for 92% of cases, mainly in the intensive care settings (50.45%). Extended-spectrum beta-lactamase was the leading resistance pattern (12.2%). Seasonal variation was observed, with a peak incidence in October-November.

CONCLUSION

The study highlights the substantial burden of bacterial meningitis among hospitalized patients, especially among high-risk groups. Emerging antimicrobial resistance emphasizes the need for optimized surveillance and stewardship. Future prospective research employing molecular techniques across multiple centers in the country is warranted to enhance understanding and guide public health strategies in Saudi Arabia.

Intrathecal and intraventricular antibiotics for postoperative Gram-negative meningitis and ventriculitis

Background:

Postoperative meningitis is a growing cause of concern, especially with the evolution of multidrug-resistant organism. The authors evaluate the use of intraventricular/intrathecal (IVT/IT) antibiotics for postoperative gram-negative meningitis in patients whom intravenous antibiotics were ineffective.

Methods:

Medical records were retrospectively reviewed and neurosurgery patients with gram-negative postoperative infection meningitis/ventriculitis were enrolled in the study. Their demographics, hospital course, and outcomes were recorded in a pro forma and analyzed using Statistical Package for the Social Sciences, version 19.

Results:

The review identified 21 patients with postneurosurgical gram-negative meningitis/ventriculitis who were treated with IVT or IT antibiotics. The most common organism was Acinetobacter species (n = 14; 66%). Amikacin was used in 7 patients, polymyxin B in 9 patients, and colistin in 5 patients. A combination of antibiotics was used in one patient. Cerebrospinal fluid sterility was achieved in all patients with no incidence of relapse. There was a single death, though that was not related to the infectious process as the patient had a massive pulmonary embolism.

Conclusion:

The findings of this study suggest that IVT and IT antibiotic therapy is a useful option in patients who are nonresponsive to standard intravenous therapy with little or no side effects.

Gram-negative bacillary meningitis in Egypt

BACKGROUND

Gram-negative bacillary meningitis (GNBM) is a rare disease with a high rate of mortality.

OBJECTIVES

The aim of this study was to describe the clinical presentation and outcome of primary and secondary GNBM and to evaluate the efficacy of ceftriaxone (a third-generation cephalosporin) in the treatment of this disease.

MATERIALS AND METHODS

A retrospective study was conducted including 95 patients with GNBM admitted to the Abbassia and Imbaba fever hospitals' meningitis wards in Egypt during the period from 1993 to the end of the year 2009. Their cerebrospinal fluid samples were subjected to conventional bacteriological methods for isolation of the causative Gram-negative bacilli. Forty-nine patients had primary GNBM (no predisposing cause of meningitis was detected) and 46 patients had secondary GNBM (with a predisposing cause of meningitis).

RESULTS

Primary GNBM was characterized by an abrupt onset and was significantly associated with typical signs of meningeal irritation. The most common infecting organisms were Salmonella typhi in 16 (33%) patients and Escherichia coli in 15 (31%) patients. Of the patients with primary GNBM, 26 (53%) were cured, 11 (22%) developed neurological sequalae, and 12 (24%) patients died. Secondary GNBM was characterized by an insidious onset and significantly associated with unarousable coma. The most common infecting organisms were Proteus mirabilis in 17 (37%) patients and Pseudomonas aeruginosa in 16 (35%) patients. The most common predisposing factor of meningitis was otitis media and occurred in 26 (57%) patients. Of the patients with secondary GNBM, 15 (33%) were cured, 15 (33%) developed neurological sequalae, and 16 (35%) died. Primary GNBM was significantly associated with a higher cure rate than secondary GNBM. The duration of symptoms in patients with secondary GNBM was significantly higher than in those with primary GNBM. Ceftriaxone was the initial drug for treatment of these patients until the antibiotic sensitivity tests were reported. The overall resistance rate to the drug was 4%.

CONCLUSION AND RECOMMENDATIONS

GNBM still has a high mortality rate and should be managed as a medical emergency. GNBM should be suspected in patients with otitis media, neurosurgical, and head trauma or who underwent spinal anesthesia and have disturbance in their level of consciousness, even if there are no signs of meningeal irritation. Ceftriaxone is still an effective drug and had a low rate of resistance in our study.

Spontaneous gram-negative bacillary meningitis in adult patients: characteristics and outcome

BACKGROUND

Spontaneous meningitis caused by gram-negative bacilli in adult patients is uncommon and poorly characterized. Our objective is to describe and compare the characteristics and the outcome of adult patients with spontaneous gram-negative bacilli meningitis (GNBM) and spontaneous meningitis due to other pathogens.

METHODS

Prospective single hospital-based observational cohort study conducted between 1982 and 2006 in a university tertiary hospital in Barcelona (Spain). The Main Outcome Measure: In-hospital mortality.

RESULTS

Gram-negative bacilli meningitis was diagnosed in 40 (7%) of 544 episodes of spontaneous acute bacterial meningitis. The most common pathogens were Escherichia coli and Pseudomonas species. On admission, characteristics associated with spontaneous gram-negative bacilli meningitis by multivariate modeling were advanced age, history of cancer, nosocomial acquisition of infection, urinary tract infection as distant focus of infection, absence of rash, hypotension, and a high cerebrospinal fluid white-cell count. Nine (23%) episodes were acquired in the hospital and they were most commonly caused by Pseudomonas. The in-hospital mortality rate was 53%. The mortality rate was higher among patients with Gram-negative bacillary meningitis than among those with other bacterial meningitis and their risk of death was twenty times higher than among patients infected with Neisseria meningitidis (odds ratio 20.47; 95% confidence interval 4.03-103.93; p<0.001).

CONCLUSIONS

Gram-negative bacilli cause 9% of spontaneous bacterial meningitis of known etiology in adults. Characteristics associated with GNBM include advanced age, history of cancer, nosocomial acquisition, and urinary tract infection as distant focus of infection. The mortality rate is higher among patients with gram-negative bacillary meningitis than among those with other bacterial meningitides.

Improving the role of intraventricular antimicrobial agents in the management of meningitis

PURPOSE OF REVIEW

The aim is to review the role of intraventricular administration of antimicrobial agents in the treatment of patients with bacterial and fungal meningitis.

RECENT FINDINGS

This article discusses indications for intraventricular antimicrobial agents, choice of antibiotics, strategies to monitor pharmacokinetics of central nervous system compartments and unanswered issues for this management approach.

SUMMARY

Intraventricular administration of antimicrobials may be necessary in certain difficult- to- eradicate central nervous system infections. There is a significant need for clinical trials and management guidelines in this area.

Management of meningitis due to antibiotic-resistant Acinetobacter species

Acinetobacter meningitis is becoming an increasingly common clinical entity, especially in the postneurosurgical setting, with mortality from this infection exceeding 15%. Infectious Diseases Society of America guidelines for therapy of postneurosurgical meningitis recommend either ceftazidime or cefepime as empirical coverage against Gram-negative pathogens. However, assessment of the pharmacodynamics of these cephalosporins in cerebrospinal fluid suggests that recommended doses will achieve pharmacodynamic targets against fewer than 10% of contemporary acinetobacter isolates. Thus, these antibiotics are poor options for suspected acinetobacter meningitis. From in vitro and pharmacodynamic perspectives, intravenous meropenem plus intraventricular administration of an aminoglycoside may represent a superior, albeit imperfect, regimen for suspected acinetobacter meningitis. For cases of meningitis due to carbapenem-resistant acinetobacter, use of tigecycline is not recommended on pharmacodynamic grounds. The greatest clinical experience rests with use of polymyxins, although an intravenous polymyxin alone is inadvisable. Combination with an intraventricularly administered antibiotic plus removal of infected neurosurgical hardware appears the therapeutic strategy most likely to succeed in this situation. Unfortunately, limited development of new antibiotics plus the growing threat of multidrug-resistant acinetobacter is likely to increase the problems posed by acinetobacter meningitis in the future.

Changing epidemiology of adult bacterial meningitis in southern taiwan: a hospital-based study

BACKGROUND

Many factors may influence the epidemiologic trend of adult bacterial meningitis (ABM). The objective of this study was to analyze recent epidemiologic trends of ABM in order to provide a better therapeutic strategy.

MATERIALS AND METHODS

The clinical features, laboratory data, and therapeutic outcomes of 181 ABM cases collected in the last 6.5 years (July 1999-December 2005) were analyzed. The results were compared with those of our previous study (202 cases, January 1986-June 1999).

RESULTS

The 181 cases consisted of 130 men (age range: 18-82 years) and 51 women (age range: 18-78 years). Monomicrobial infection and mixed infection were found in 165 cases and 16 cases, respectively. A preceding postneurosurgical state was noted in 56.9% (103/181) of cases. Despite a decrease in incidence, Klebsiella pneumoniae (25.5%, 42/165) was still the most common pathogen. A marked increase of Acinetobacter meningitis (11.5%, 19/165) was noted, which replaced Pseudomonas meningitis as the second most common Gram-negative pathogen in ABM. A marked increase in staphylococcal infection, accounting for 23% (38/165) of all cases, was also noted, of which 76% (29/38) were methicillin-resistant strains. The therapeutic result showed a mortality rate of 30.3% (55/181). Significant prognostic factors included septic shock and age at infection.

CONCLUSIONS

This study revealed a change in the epidemiologic trend of ABM, with an increase in the number of patients with a postneurosurgical state and a rising incidence of Acinetobacter and staphylococcal infections. Clinicians should pay greater attention to these changes, which may affect their management of ABM.

Intraventricular or intrathecal use of polymyxins in patients with Gram-negative meningitis: a systematic review of the available evidence

Several reports have described the use of polymyxins by the intraventricular or intrathecal route for multidrug-resistant Gram-negative meningitis. We reviewed the available clinical evidence regarding intraventricular/intrathecal administration of polymyxins in patients with meningitis, focusing on effectiveness and safety. Relevant studies were identified from PubMed (January 1950 to April 2006) as well as from the references of relevant articles. We identified 31 case reports/series that matched our inclusion criteria. Sixty-four episodes of Gram-negative meningitis (34 in adults) were reviewed. Monotherapy with polymyxins via the intraventricular or intrathecal route was used in 11 episodes and combination of systemic and local polymyxins was used in 25 episodes. In the remaining episodes, various combinations of local polymyxins with systemic and/or local antibiotics were administered. Cure was achieved in 51/64 episodes (80%); in 26/30 episodes (87%) due to Pseudomonas aeruginosa and in 10/11 episodes (91%) due to Acinetobacter spp. Toxicity related to local administration of polymyxins was noted in 17/60 (28%) patients. The most common toxicity was meningeal irritation (12 cases). Discontinuation of treatment was necessary in four episodes and dose reduction in four episodes; irreversible toxicity was not reported. The limited available evidence suggests that therapy with intraventricular/intrathecal polymyxins alone or in combination with systemic antimicrobial agents is effective against Gram-negative meningitis. Toxicity is not uncommon but it is dose-dependent and reversible. Further studies are needed to evaluate the criteria for initiation of local central nervous system treatment with polymyxins, the optimal dosages and the role of adjuvant systemic or local therapy.

Central nervous system infection caused by Morganella morganii

Central nervous system (CNS) infection with Morganella morganii is very rare. We describe a 38-year-old female patient with frontal brain abscess caused by M morganii who was unsuccessfully treated. We also review all reported cases of Morganella CNS infections with an emphasis on treatment modalities and outcomes. Aggressive surgical management and appropriate antimicrobial therapy can lead to cure, but the mortality rate for these infections remains high.

Third-generation cephalosporin resistance among Gram-negative bacilli causing meningitis in neurosurgical patients: significant challenges in ensuring effective antibiotic therapy

OBJECTIVES

The treatment of meningitis caused by Gram-negative bacilli in neurosurgical patients is a major challenge because of the complexity of these patients, the emergence of antibiotic resistance in many of the causative organisms and the restricted choice of antibiotics suitable for use, owing to a failure to achieve high enough concentrations in the CSF. We reviewed the incidence, aetiology, treatment and outcome of all patients with Gram-negative bacillary meningitis (GNBM) in our centre over a 7 year period.

METHODS

Beaumont Hospital, Dublin is a 720 bed tertiary referral hospital and contains the national neurosurgical centre for the Republic of Ireland. The case notes and microbiological records of all patients with GNBM between 1998 and 2004 inclusive were reviewed retrospectively. Only patients with positive CSF culture and clinical features compatible with meningitis were included.

RESULTS

Forty separate episodes of GNBM involving 34 different patients occurred during the study period. The most common causative organisms were Enterobacter spp. (35%), Escherichia coli (22.5%) and Pseudomonas aeruginosa (15%). Twenty-five per cent of isolates were resistant to third-generation cephalosporins. The median duration of treatment was 19.2 days and a combination of intravenous and intraventricular antibiotics was the most common treatment regimen used. Mortality directly related to GNBM was 2.5%.

CONCLUSIONS

Although the mortality directly related to GNBM was low, the emergence of strains resistant to third-generation cephalosporins represents a therapeutic challenge. Treatment with combined intravenous and intraventricular antibiotics is recommended for 2-3 weeks, but more studies are required to determine the optimal management of this difficult condition.

Nosocomial enterobacter meningitis: risk factors, management, and treatment outcomes

Enterobacter species are increasingly a cause of nosocomial meningitis among neurosurgery patients, but risk factors for these infections are not well defined. A review of all adult patients hospitalized at the University of California-Los Angeles (UCLA) Medical Center during an 8-year period identified 15 postneurosurgical cases of Enterobacter meningitis (EM). Cure was achieved in 14 cases (93%), and efficacy was similar for carbapenem- and cephalosporin-based treatment. A matched case-control study comparing 26 controls with 13 case patients hospitalized exclusively at the UCLA Medical Center found that external cerebrospinal fluid (CSF) drainage devices (odds ratio [OR], 21.8; P=.001), isolation of Enterobacter species from a non-CSF culture (OR, 24.6; P=.002), and prolonged administration of antimicrobial drugs before the diagnosis of meningitis that were inactive in vitro against Enterobacter species (OR, 13.3; P=.008) were independent risk factors for EM. Despite favorable treatment outcomes, EM is a serious infection associated with Enterobacter species colonization or infection at other surgical sites, with selective antimicrobial pressure, and with invasive CNS devices.

Brain abscess caused by aerobic Gram-negative bacilli: clinical features and therapeutic outcomes

Thirty-three patients (24 males and nine females) with brain abscesses resulting from infection by aerobic Gram-negative bacilli were identified at Kaohsiung Chang Gung Memorial Hospital over a period of 14 years. Of these, 23 cases developed spontaneously, with the remaining ten postneurosurgery. The organisms most frequently involved were Klebsiella (K.) pneumoniae, Pseudomonas aeruginosa, Escherichia coli and Proteus species and included some rare pathogens, such as Salmonella and Enterobacter species, K. oxytoca, Vibrio and Morganella morganii. Apart from one exception, the locations of the abscess were supratentorial. Twenty-four patients presented with a single abscess, while nine revealed multiple abscesses, with 26 treated surgically and seven with antibiotics exclusively. In total, seven patients died, representing an overall mortality rate of 21%. This study demonstrates that brain abscesses associated with neurosurgical procedures are not rare, accounting for 30% of cases in this study, with K. pneumoniae, Proteus and Enterobacter species the most prevalent of the revealed pathogens. Further, Proteus species were the most prevalent pathogens demonstrated for cases of both otogenic and polymicrobial infections. If brain abscesses are diagnosed for diabetic patients or have a gas-forming appearance, a diagnosis of K. pneumoniae infection should be considered, with particular attention paid to detection of other metastatic septic abscesses. In light of the high mortality rate, early treatment is essential to maximize the chances of survival.

Klebsiella meningitis in adults: clinical features, prognostic factors and therapeutic outcomes

Sixty adult Klebsiella meningitis patients have been identified at Kaohsiung Chang Gung Memorial Hospital in a period of 13 years. Most cases were associated with debilitating diseases, and devastating metastatic septic abscesses are common in diabetic patients with K. pneumoniae meningitis. Although the mortality rate has been significantly reduced in recent years, there has been an increase in nosocomial infections and the emergence of multi-antibiotic resistant strains. Significant prognostic factors include appropriate antibiotic therapy, the presence of septic shock, disseminated intravascular coagulation, and high cerebrospinal fluid protein levels and white blood cell counts. Initial empiric therapy with a third generation cephalosporin should be considered for community-acquired meningitis while antibiotics such as carbapenems should be considered as initial empiric therapy for patients with postneurosurgical meningitis. Early diagnosis and the use of appropriate antibiotics are of crucial importance.

Frequent association with neurosurgical conditions in adult Proteus mirabilis meningitis: report of five cases

Adult Proteus (P.) mirabilis meningitis is relatively rare and has not been examined individually in the English-language literature. During a period of 15 years (January 1986-December 2000), four adult patients with P. mirabilis meningitis and one adult patient with mixed bacterial meningitis involving P. mirabilis were identified at Chang Gung Memorial Hospital, Kaohsiung. These five patients included one man and four women, aged from 19 to 74 years (mean age=55.4). P. mirabilis infection accounted for 1.7% (4/229) of cases of our culture-proven monomicrobial adult bacterial meningitis and was involved in 7.1% (1/14) of cases of our adult mixed bacterial meningitis during this period. Underlying debilitating conditions including diabetes mellitus and neurosurgical disorders were common in these five cases. Adult P. mirabilis meningitis had an acute clinical course, with fever and consciousness-disturbance occurring as most prominent clinical manifestations in all patients. Other common manifestations included hydrocephalus, seizure, septic shock and wound infection. Hematogenous spread would appear to be the most likely mechanism. Multi-antibiotic resistant strains of P. mirabilis were not found in our patients. All strains were susceptible to third-generation cephalosporins, imipenem, aztreonam and ciprofloxacin. The results of treatment for adult P. mirabilis meningitis were not satisfactory, most of the patients surviving with severe neurological deficit.

Adult bacterial meningitis in Southern Taiwan: epidemiologic trend and prognostic factors

In two investigative phases over a 13.5-year study period (January 1986-June 1999), 202 adult patients with culture-proven bacterial meningitis were enrolled in this study. In order to determine the epidemiologic trend, prognostic factors and therapeutic results for this disease. Klebsiella pneumoniae (K. pneumoniae), Pseudomonas aeruginosa, and Streptococcus pneumoniae were the three most commonly revealed pathogens, accounting for about 48% of the episodes. Although there was a change in relative frequency for the pathogens, K. pneumoniae remained the most prevalent during the two periods studied (January 1986-December 1992 and January 1993-June 1999). Multiantibiotic resistant strains have been in evidence since their appearance in 1994, with most of our patients acquiring their infection nosocomially. The overall mortality rates during the two periods were 40% and 34%, respectively. In stepwise logistic regression analysis, only initial conscious level, appropriate antibiotic therapy and septic shock were independently associated with mortality, after adjustment for other potentially confounding factors. Initial empirical antibiotics with both third-generation cephalosporin and penicillin G, should be considered for the majority of meningitis cases resulting from infection with Gram-negative bacilli and streptococcal species. Besides the evolution of newer pathogens, there has been increasing incidence for nosocomially acquired bacterial meningitis for patients postneurosurgery, with the emergence of resistant strains presenting a therapeutic challenge in recent years. Vancomycin and imipenem/cilastatin should be considered as the initial empirical antibiotics of choice for the treatment of this special group of patients.