Antibiotic therapy for enterobacter meningitis: a retrospective review of 13 episodes and review of the literature

Spontaneous Proteus mirabilis Meningitis in Adults Requiring an Extended Antibiotic Course: Case Report and Literature Review

Most cases of gram-negative bacillary meningitis occur in neonates and infants. Meningitis in adults caused by Proteus mirabilis has been reported rarely. Evidence-based guidelines for the treatment of adult patients with gram-negative bacillus meningitis are scarce. The optimal duration of antibiotic therapy for these patients is an unanswered question in the medical literature. This article outlines a case of community-acquired meningitis caused by P. mirabilis in an adult patient who required an extended antimicrobial treatment, after failing to a three-week antibiotic regime. Our patient, a 66-year-old man with a history of neurogenic bladder, remote spinal cord trauma, and recurrent urinary tract infections presented to the emergency department reporting a two-day history of severe headache, fever, and confusion. Cerebrospinal fluid (CSF) revealed significant neutrophil-predominant pleocytosis, low glucose level, and elevated protein level. CSF culture grew few pan-susceptible P. mirabilis. The patient initially completed 21 days of ceftriaxone guided by susceptibility testing. Nine days after finishing antibiotic therapy, the patient was readmitted with recurrent headache, fever, and neck rigidity. A new CSF study again revealed pleocytosis, elevated polymorphonuclear cells, low glucose level, and elevated protein level, but with a negative CSF culture. The patient became afebrile, and his symptoms improved after two days of ceftriaxone. He completed an additional six-week regime of ceftriaxone. On the one-month follow-up visit, the patient remained afebrile, with no recurrent symptoms. Spontaneous community-acquired P. mirabilis meningitis is rare among adult patients. Experiences in the treatment of gram-negative bacillus meningitis in adults must be shared with the scientific community to build up a better understanding of this condition. In the context of this case, sterilization of the CSF, extended antibiotic therapy, and a close post-treatment follow-up are crucial for treating this life-threatening condition.

Intraventricular treatment of paediatric meningitis due to extensively drug-resistant Gram-negative bacteria: two case reports and review of the literature

Nosocomial meningitis caused by Gram-negative bacteria is associated with increasingly common neurosurgical procedures in children, with an increase in incidence recently reported. These infections are associated with an increased risk of mortality, prolonged hospitalisation, and increased costs. In this report, we describe two paediatric cases with central nervous system infections caused by extensively drug-resistant Gram-negative bacteria that were successfully treated with intraventricular colistin. To the best of our knowledge, this is the first comprehensive review and discussion of intraventricular antimicrobial therapy in a paediatric population. Based on our comprehensive review of the relevant literature, it appears that intraventricular administration of colistin may be a promising and effective option in the treatment of central nervous system infections in children who do not respond to other treatment options.

Antimicrobial susceptibility pattern of carbapenemase-producing Gram-negative nosocomial bacteria at Al Zahra hospital, Isfahan, Iran

BACKGROUND AND OBJECTIVES

Bacterial antibiotic resistance is one of the most important threats for public health around the world. Carbapenemase-producing Gram-negative bacteria have resistance to most antibiotics including carbapenems complicating the treatment of infections. The aim of this study was to determine the antimicrobial susceptibility pattern of carbapenemase-producing nosocomial Gram-negative pathogens at a referral teaching hospital to reveal the best options for treatment of related infections.

MATERIALS AND METHODS

Gram-negative bacteria, isolated from hospitalized patients with nosocomial infections, underwent meropenem susceptibility test by disk diffusion method. Meropenem-resistant strains were evaluated for the presence of carbapenemase using Modified Hodge test (MHT). Finally, the antibiotic susceptibility test was performed to determine the sensitivity of each carbapenemase-positive strain against various antimicrobial agents according to the guidelines of Clinical and Laboratory Standards Institute (CLSI).

RESULTS

Over the study period, 155 carbapenemase-positive isolates were detected. Pneumonia was the most frequent related nosocomial infection (67.1%) followed by UTI (23.2%). Acinetobacter baumannii (53.5%) and Klebsiella pneumoniae (40%) were the most frequently isolated pathogens. The pathogens had high rate of resistance to all antibiotics. Colistin had the most in vitro effect against all pathogens. Also, K. pneumoniae had a co-trimoxazole sensitivity rate equal to colistin (30.6%).

CONCLUSION

Carbapenemase-positive Gram-negative bacteria causing nosocomial infections are common in our hospital and have high rate of resistance to most antibiotics. Improvement in the pattern of antibiotic use and infection control measures are necessary to overcome this resistance.

2017 Infectious Diseases Society of America's Clinical Practice Guidelines for Healthcare-Associated Ventriculitis and Meningitis

The Infectious Diseases Society of America (IDSA) Standards and Practice Guidelines Committee collaborated with partner organizations to convene a panel of 10 experts on healthcare-associated ventriculitis and meningitis. The panel represented pediatric and adult specialists in the field of infectious diseases and represented other organizations whose members care for patients with healthcare-associated ventriculitis and meningitis (American Academy of Neurology, American Association of Neurological Surgeons, and Neurocritical Care Society). The panel reviewed articles based on literature reviews, review articles and book chapters, evaluated the evidence and drafted recommendations. Questions were reviewed and approved by panel members. Subcategories were included for some questions based on specific populations of patients who may develop healthcare-associated ventriculitis and meningitis after the following procedures or situations: cerebrospinal fluid shunts, cerebrospinal fluid drains, implantation of intrathecal infusion pumps, implantation of deep brain stimulation hardware, and general neurosurgery and head trauma. Recommendations were followed by the strength of the recommendation and the quality of the evidence supporting the recommendation. Many recommendations, however, were based on expert opinion because rigorous clinical data are not available. These guidelines represent a practical and useful approach to assist practicing clinicians in the management of these challenging infections.

Risk factors for relapse or persistence of bacteraemia caused by Enterobacter spp.: a case-control study

Background

Enterobacter spp. possess chromosomal AmpC beta-lactamases that may be expressed at high levels. Previous studies have demonstrated a risk of relapsed bacteraemia following therapy with third generation cephalosporins (3GCs). What additional factors predict microbiological failure in Enterobacter bacteraemia is unclear. We aimed to determine factors associated with microbiological failure in Enterobacter bacteraemia.

Methods

We retrospectively identified cases of bacteraemia caused by Enterobacter spp. occurring in four hospitals. Using a case–control design, we determined clinical risk factors for persistence or relapse defined as repeated positive blood cultures collected between 72 hours and up to 28 days post initial positive blood culture.

Results

During the study period a total of 922 bacteraemia events caused by Enterobacter spp. in adults were identified. The overall risk of relapsed or persisting bacteraemia at 28 days was low (31 of 922, 3.4%), with only 2 patients experiencing emergent resistance to 3GCs. A total of 159 patients were included in the case–control study. Using multivariate logistic regression, independent predictors for relapse were a line-associated source of infection (OR 3.87; 95% CI 1.56-9.60, p = 0.004) and the presence of immunosuppression (OR 2.70; 95% CI 1.14-6.44, p = 0.02). On univariate analysis definitive therapy with a broad-spectrum beta-lactam-beta-lactamase inhibitor (BLBLI, e.g. piperacillin-tazobactam) was not associated with relapse (OR 1.83; 95% CI 0.64-5.21, p = 0.26) although the proportion of patients receiving a BLBLI as definitive therapy was relatively small (21/159, 13.2%).

Conclusions

The risk of relapsed or persistent Enterobacter bacteraemia appears to be low in Australia. A line-associated source of infection and immunocompromise were significant independent predictors for relapse. Larger, preferably randomized, studies are needed to address whether BLBLIs represent an effective carbapenem-sparing option for Enterobacter bacteraemia.

Electronic supplementary material

The online version of this article (doi:10.1186/s13756-017-0177-0) contains supplementary material, which is available to authorized users.

Treatment of multidrug-resistant Gram-negative infections in children

Antibiotic resistance in conjunction with the erosion of the drug development pipeline may lead us into a bleak future, a "post-antibiotic era." Because of a shortage of studies addressing treatment options for multidrug-resistant Gram-negative (MDRGN) infections in children, data must be extrapolated from the adult literature. However, even adult studies are limited by significant methodological flaws. We are in urgent need of pediatric specific pharmacokinetic/pharmacodynamic data for agents with activity against MDRGN infections as well as improved clinical outcomes studies. For the time being, we must rely on in vitro studies, observational data, and clinical experience to guide our therapeutic decisions. In this review, we discuss treatment considerations for infections caused by extended-spectrum β-lactamase-producing organisms, AmpC β-lactamase-producing organisms, carbapenem-resistant Enterobacteriaceae, carbapenem-resistant Pseudomonas aeruginosa, and carbapenem-resistant Acinetobacter baumannii in the pediatric population.

Antibiotic therapy for inducible AmpC β-lactamase-producing Gram-negative bacilli: what are the alternatives to carbapenems, quinolones and aminoglycosides?

Some bacteria that possess chromosomally determined AmpC β-lactamases may express these enzymes at a high level following exposure to β-lactams, either by induction or selection for derepressed mutants. This may lead to clinical failure even if an isolate initially tests susceptible in vitro, a phenomenon best characterised by third-generation cephalosporin therapy for Enterobacter bacteraemia or meningitis. Several other Enterobacteriaceae, such as Serratia marcescens, Citrobacter freundii, Providencia spp. and Morganella morganii (often termed the 'ESCPM' group), may also express high levels of AmpC. However, the risk of clinical failure with β-lactams that test susceptible in vitro is less clear in these species than for Enterobacter. Laboratories frequently do not report β-lactam or β-lactamase inhibitor combination drug susceptibilities for ESCPM organisms, encouraging alternative therapy with quinolones, aminoglycosides or carbapenems. However, quinolones and carbapenems present problems with selective pressure for multiresistant organisms, and aminoglycosides with potential toxicity. The risk of emergent AmpC-mediated resistance for non-Enterobacter spp. appears rare in clinical studies. Piperacillin/tazobactam may remain effective and may be less selective for AmpC derepressed mutants than cephalosporins. The potential roles for agents such as cefepime or trimethoprim/sulfamethoxazole are also discussed. Clinical studies that better define optimal treatment for this group of bacteria are required.

Salmonella meningitis in an adult with type B viral hepatitis and an incidental schwannoma

Salmonella meningitis is an unusual complication of Salmonella sepsis that occurs almost exclusively in infants and young children. Cases that do occur in adults are associated with a high morbidity and mortality. The present study concerns a rare case of Salmonella meningitis, the first to be reported in Qatar, in a previously healthy young adult man who was admitted with fever, headache and nuchal rigidity. Cerebrospinal fluid (CSF) culture produced Salmonella paratyphi A, although cultures of blood were negative. The patient was admitted to the medical intensive care unit (MICU) and assisted with mechanical ventilation for 1 week, then transferred to the medical ward where he exhibited progressive improvement on treatment with meropenam for 3 weeks. The patient was found to have an incidental schwannoma causing right-sided hydronephrosis, and hydroureter, treated with double J stent insertion. He was discharged in good condition without any neurological sequelae.

Nontraumatic pneumocephalus due to nosocomial Enterobacter cloacae infection

Nosocomial meningitis is rare, and routine cerebrospinal fluid study is seldom recommended for hospitalized patients with fever and acute delirium. We present a case of Enterobacter cloacae meningitis complicated with a nontraumatic pneumocephalus. Maintaining a high index of suspicion of nosocomial meningitis is crucial in patients with acute delirium and multiple underlying comorbid conditions.

Enterobacter sakazakii: a coliform of increased concern to infant health

The first cases of neonatal meningitis believed to have been caused by Enterobacter sakazakii were reported in 1961. Prompted by several subsequent outbreaks of E. sakazakii infections in neonates and an increasing number of neonates in intensive care units being fed rehydrated powdered infant formula, considered to be a source of the pathogen, public health authorities and researchers are exploring ways to eliminate the bacterium or control its growth in dry infant formula, processing environments and formula preparation areas in hospitals. Reviewed here are advances in taxonomy and classification of E. sakazakii, methods of detecting, isolating and typing the bacterium, antibiotic resistance, clinical etiology and pathogenicity. Outbreaks of E. sakazakii infections in neonates and adults are summarized. Reports on the presence of E. sakazakii in clinical settings, the environment and foods and food processing facilities are reviewed. Tolerance of the pathogen to environmental stresses, its behavior in powdered and rehydrated infant formulae and hazard analysis and risk management are discussed. Research needs are presented.

Enterobacter meningitis: organism susceptibilities, antimicrobial therapy and related outcomes

BACKGROUND

Meningitis due to Enterobacter species is an uncommon infection in adults; however, when present, treatment is frequently complicated by resistance of many Enterobacter isolates to third-generation cephalosporins and poor central nervous system penetration of other antibiotics. The aim of this study was to retrospectively review cases of meningitis caused by Enterobacter species at our institution, to better characterize patient factors, pathogen characteristics, and treatment options for this infection.

METHODS

We reviewed all cases of Enterobacter meningitis in a 12-year period at a tertiary care center. Data collected included patient demographics, antibiotic sensitivities of Enterobacter isolates, antimicrobial therapy, and patient outcomes.

RESULTS

Nineteen cases were identified, primarily in patients with neurotrauma and in neurosurgical patients. Enterobacter cloacae was the most frequent Enterobacter species isolated followed by Enterobacter aerogenes and Enterobacter agglomerans (50%, 34%, and 16% of cultures, respectively). Overall, clinical cure/improvement was achieved in 47% of patients, and the mortality rate was 21%. Antibiotic treatment varied substantially and included third-generation cephalosporins, intravenous and intrathecal aminoglycosides, trimethoprim-sulfamethoxazole (TMP-SMX), piperacillin, ciprofloxacin, and other miscellaneous antibiotics. Treatment with TMP-SMX was associated with a high rate of clinical cure/improvement, whereas third-generation cephalosporins were less efficacious.

CONCLUSIONS

Enterobacter meningitis is an infrequent complication of neurological insult. Treatment is often complicated by resistance of Enterobacter species to third-generation cephalosporins. Our results indicate that while third-generation cephalosporins are not the most appropriate choice of agents to treat Enterobacter meningitis, TMP-SMX may yield satisfactory results.

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.

Enterobacter sakazakii infections among neonates, infants, children, and adults. Case reports and a review of the literature

Enterobacter sakazakii can cause serious infections especially among the very young and the elderly. It continues to be more common among neonates and infants than adults. Its tropism for the central nervous system in neonates and infants remains a mystery. Among neonates and infants, E. sakazakii has a propensity to cause meningitis resulting in ventriculitis, brain abscess or cyst formation, and development of hydrocephalus requiring ventricular-peritoneal shunt. Computed tomography of the head is therefore useful in following patients with E. sakazakii meningitis. Mortality and morbidity of E. sakazakii meningitis is high, and virtually all patients recovering from the central nervous system infection suffered mental and physical developmental delays. The case-fatality rate decreased among patients with meningitis treated with the third-generation cephalosporins. Most adults with E. sakazakii infection had serious underlying diseases and 50% of the adults with the infection had malignancies. However there has never been a known case of meningitis. Increasing antibiotic resistance among Enterobacter species should lead one to consider using the carbapenems or the newer cephalosporins in combination with a second agent such as an aminoglycoside. Limited data suggest that trimethoprim-sulfamethoxazole may be a useful agent in the treatment of infections caused by the Enterobacter species, especially in view of the production of extended-spectrum beta-lactamases capable of inactivating the cephalosporins and extended-spectrum penicillin.

Monotherapy versus combination therapy for bacterial infections

The authors discuss the latest findings regarding the use of one or more antimicrobial drugs for a variety of infections. They offer suggestions for treatment based on a host of considerations, including the synergy and antagonism of specific drugs, type of infection, potential toxicities, and cost.

Enterobacter spp.: pathogens poised to flourish at the turn of the century

Knowledge of the genus Enterobacter and its role in human disease has expanded exponentially in recent years. The incidence of infection in the hospital and the community has increased. New clinical syndromes have been recognized. Enterobacter spp. have also been implicated as causes of other syndromes that traditionally have been associated almost exclusively with more easily treatable pathogens, such as group A streptococci and staphylococci. Rapid emergence of multiple-drug resistance has been documented in individual patients during therapy and in populations and environments with strong selective pressure from antimicrobial agents, especially the cephalosporins. Therapeutic options for patients infected with multiply resistant strains have become severely limited. Carbapenems or, alternatively, fluoroquinolones are the most predictively active options, although resistance to both classes has been observed on rare occasions. Enterobacter spp. appear well adapted for survival and even proliferation as the turn of the century approaches.