Penicillin-resistant pneumococci in adult disease with special reference to AIDS patients

Characteristics of the major etiologic agents of bacterial meningitis isolated in Poland in 1997-1998

Bacterial meningitis remains a major cause of morbidity and mortality worldwide, especially in children. In this paper, we present the results of the first two years (1997-98) of activity of the National Reference Centre for Bacterial Meningitis (NRCBM) on the etiologic agents of bacterial meningitis in Poland. Of the 220 isolates sent to the NRCBM, the most frequently identified was Neisseria meningitidis (n = 90, 40.9%), followed by Haemophilus influenzae (n = 58, 26.4%), and Streptoccus pneumoniae (n = 46, 20.9%). Of the meningococcal isolates, 88.9% belonged to serogroup B and 10.0% to serogroup C, and the most prevalent serotype was 22 (43.3%). Most meningococci were highly sensitive to penicillin; however, 10% of them had decreased susceptibility to penicillin. More than 90% of H. influenzae belonged to serotype b, and all were susceptible to third generation cephalosporins and chloramphenicol. A broad distribution of serotypes was found among pneumococcal isolates, of which the most common were serotypes 3 and 8. Penicillin nonsusceptible isolates constituted 13% of all pneumococcal isolates. Three of the resistant pnemococci belonged to serotype 23F. Data presented in this paper demonstrate the current epidemiological situation of bacterial meningitis in Poland.

Impact of antibiotic resistance on chemotherapy for pneumococcal infections

Over the past three decades, penicillin-resistant pneumococci have emerged worldwide. In addition, penicillin-resistant strains have also decreased susceptibility to other beta-lactams (including cephalosporins) and these strains are often resistant to other antibiotic groups, making the treatment options much more difficult. Nevertheless, the present in vitro definitions of resistance to penicillin and cephalosporins in pneumococci could not be appropriated for all types of pneumococcal infections. Thus, current levels of resistance to penicillin and cephalosporin seem to have little, if any, clinical relevance in nonmeningeal infections (e.g., pneumonia or bacteremia). On the contrary, numerous clinical failures have been reported in patients with pneumococcal meningitis caused by strains with MICs > or = 0.12 microg/ml, and penicillin should never be used in pneumococcal meningitis except when the strain is known to be fully susceptible to this drug. Today, therapy for pneumococcal meningitis should mainly be selected on the basis of susceptibility to cephalosporins, and most patients may currently be treated with high-dose cefotaxime (+/-) vancomycin, depending on the levels of resistance in the patient's geographic area. In this review, we present a practical approach, based on current levels of antibiotic resistance, for treating the most prevalent pneumococcal infections. However, it should be emphasized that the most appropriate antibiotic therapy for infections caused by resistant pneumococci remains controversial, and comparative, randomized studies are urgently needed to clarify the best antibiotic therapy for these infections.

Unusual manifestations of invasive pneumococcal infection

Unusual pneumococcal infections occurred frequently in the preantibiotic age but rapidly declined with the advent of the antibiotic era. Unfortunately, the morbidity and mortality associated with invasive pneumococcal disease remain high despite antibiotic therapy and monumental advances in medical technology. The incidence of invasive pneumococcal disease has increased recently because of the onset of the human immunodeficiency virus (HIV) epidemic and the emergence of antibiotic-resistant pneumococcus. Robert Austrian described the clinical triad of pneumococcal pneumonia, meningitis, and endocarditis, a syndrome that now bears his name. Although seen infrequently today, unusual manifestations of pneumococcal infection such as those Austrian reported still occur. A review of these cases is warranted because, as drug-resistant organisms continue to emerge worldwide, more unusual pneumococcal infections will be seen. Streptococcus pneumoniae is responsible for a remarkable array of disease processes; our literature review uncovered 95 different types of unusual pneumococcal infections representing 2,064 cases. Examples of these infections included pancreatic and liver abscesses, aortitis, gingival lesions, phlegmonous gastritis, inguinal adenitis, testicular and tubo-ovarian abscesses, and necrotizing fasciitis. We also reviewed predisposing underlying illnesses and conditions. Alcoholism, HIV infection, splenectomy, connective tissue disease, steroid use, diabetes mellitus, and intravenous drug use remain common risk factors for invasive pneumococcal infections. Currently, multidrug-resistant S. pneumoniae remains susceptible to vancomycin and several new third-generation fluoroquinolones. As what some fear will be a possible postantibiotic era approaches, clinicians must be able to recognize and manage unusual pneumococcal infections.

Invasive pneumococcal infections. A comparison between adults and children

A similar number of adults and children had invasive pneumococcal infection. There was male predominance, and different ethnic distribution between children and adults. The majority of adults (78%), had underlying diseases, but this was less frequent in children (24%). The presenting illness differed between adults and children. Complications of invasive pneumococcal infection occurred more frequently in adults than in children. The mortality rate in adults was 21.5%; in children, only 3.8%. The rate of penicillin-resistant pneumococci at our hospital was 23%, while cefotaxime resistance was 4.2%. Penicillin-resistant pneumococci were not isolated more frequently from children than from adults. Patients with penicillin-resistant pneumococci had longer duration of hospitalization and more nosocomially acquired infections. No difference in the mortality rate was found between patients with resistant or sensitive pneumococci. Ninety-five percent of strains were included in the current vaccine, but less than 2% of patients had been vaccinated. Isolates prevalent in Europe and the United States (19, 5, 1, 14, 6, 18, 12, 4, 9, 23, 7) were also most prevalent in Jerusalem. The distribution of serotypes differed between children and adults, and between patients from whom resistant organisms were isolated as opposed to sensitive organisms.

Antimicrobial susceptibilities and serotypes of invasive Streptococcus pneumoniae strains in Switzerland

In 1993 and 1994, 10 microbiological laboratories in Switzerland collected 351 strains of Streptococcus pneumoniae from invasive infections. Susceptibilities to the main representatives of the chemical classes were as follows: penicillin, 93%; chloramphenicol, 92%; erythromycin, 94%; sulfamethoxazole-trimethoprim, 86%; tetracycline, 92%; vancomycin, 100%. Forty-three strains showed resistance to one agent, and 35 strains showed resistance to two or more antimicrobial agents simultaneously; i.e., 22% of the strains were resistant to at least one antimicrobial agent. Four strains (1%) were fully resistant to penicillin, whereas 21 strains (6%) showed reduced susceptibility. Of these 25 strains not fully susceptible to penicillin, 10 were resistant to one, 3 were resistant to two, and 8 were resistant to three additional antimicrobial agents. Of the quinolones, sparfloxacin was the most active substance, with an MIC at which 90% of the strains are inhibited of 0.5 mg/liter. The most common serotypes were types 6 (13.6% of isolates), 7 (10.5%), 19 (10.5%), 14 (9.1%), and 1 (8.5%) as well as 3 and 23 (8.0% each). Reduced susceptibility to penicillin was found mainly among serotypes 6, 14, 19, and 23. The currently available 23-valent pneumococcal vaccine covers 320 (91%) of the pneumococci isolated. Regional differences within Switzerland with regard to serotypes and antimicrobial resistance were not observed.