Prevalence Of Penicillin Resistance Research Articles

Prevalence of Penicillin Resistance Among Streptococcus pneumoniae Isolates in a General Hospital in Southwest Saudi Arabia: A Five-Year Retrospective Study.

Background The rise in infections caused by penicillin-resistant strains of Streptococcus pneumoniae has become a global concern. However, the magnitude of this problem in Southwest Saudi Arabia has never been investigated. Therefore, this study aims to determine the prevalence of this bacteria in the region using in vitro data. Materials and methods This study retrospectively studied pneumococcal isolates collected by the Microbiology Laboratory of a general hospital in Al Baha, Saudi Arabia, from January 2013 to December 2017. A minimum inhibitory concentration (MIC) ≥ 8 mg/L was used as a cutoff concentration to detect the resistant isolates. Results A total of 201 S. pneumoniae isolates were identified using the VITEK® 2 system (bioMérieux SA, Marcy-l'Étoile, France). Most of these isolates (61%) were obtained from respiratory specimens, including sputum, tracheal aspirates, and bronchoalveolar lavage. Eye swabs accounted for 15% of the isolates, blood samples contributed 12%, ear swabs accounted for 7%, and cerebrospinal fluid (CSF) 3.4%. The resistance of S. pneumoniae during the five years varied from 61% to 76%, with an overall resistance of 70% (141/201). The resistance rate per year was 71% (43/60) in 2013, 76% (35/46) in 2014, 61% (22/36) in 2015, 68% (20/29) in 2016, and 66% (21/30) in 2017. Conclusion The data confirm the presence of penicillin-resistant S. pneumoniae in Southwest Saudi Arabia. Furthermore, the high resistance suggests a potential concern, emphasizing the need for penicillin control, surveillance, and vaccination to address this growing problem.

Pneumococcal carriage among sickle cell disease patients in Accra, Ghana: Risk factors, serotypes and antibiotic resistance.

BackgroundPneumococcal carriage is the precursor for development of pneumococcal disease, and is also responsible for transmission of the organism from person-to-person. Individuals with Sickle Cell Disease (SCD) are more likely to develop invasive disease with S. pneumoniae compared to their healthy counterparts and the presentation of disease in the former is usually abrupt and severe. In Africa, little is known about the pneumococcus in relation to people with SCD Sickle Cell Disease (SCD). The aim of the study was to investigate the epidemiology of pneumococcal carriage among SCD patients including the carriage prevalence, risk factors, serotypes and antibiotic resistance.MethodThis was a cross sectional study involving 402 SCD patients recruited from Korle Bu Teaching Hospital and Princess Marie Louis Hospital in Accra from October 2016 to March 2017. The study subjects included 202 children of the age groups: ≤5 years (94), >5–9 years (75), ≥10–13 years (33) and 200 adults of the age groups: 14–20 years (46), 21–40 years (112), 41–60 years (25), ≤ 61 years (17). Nasopharyngeal (NP) swabs were collected from the study participants as well as epidemiological data on demographic, household and clinical features. The NP specimens were cultured for S. pneumoniae and the isolates were serotyped by latex agglutination. Antimicrobial susceptibility tests of the isolates were done by the disc diffusion test and E-test.ResultsPrevalence of S. pneumoniae carriage among children and adult SCD patients enrolled in the study were 79/202 (39.1%; 95% CI: 32.3 to 46.2) and 20/200 (10.0%; 95% CI: 6.2 to 15.0) respectively. Risk factors associated with pneumococcal carriage were age (OR = 1.137; 95% CI: 1.036–1.248; p = 0.007) and runny nose (OR = 5.371; 95% CI: 1.760–16.390; p = 0.003). Overall, twenty-six pneumococcal serotypes were isolated from the study participants and the predominant serotype was 6B (10.6%), followed by 23B (8.2%). Among the children, serotype coverage of the 13-valent Pneumococcal Conjugate Vaccine, which is currently used in Ghana was 32.4%. Prevalence of penicillin resistance among the pneumococcal isolates was 37.4% (37/99) and all the penicillin-resistant isolates exhibited intermediate penicillin resistance with the exception of one isolate that showed full resistance and was susceptible to ceftriaxone. Prevalence of resistance to the other antibiotics ranged from 2.5% (levofloxacin) to 85% (cotrimoxazole). Multidrug resistance occurred among 34.3% (34/99) of the pneumococcal isolates.ConclusionPneumococcal carriage was four-fold higher in SCD children than adults and was characterized by predominance of non-vaccine serotypes and considerable level of multidrug resistance, though penicillin, cefotaxime and levofloxacin resistance appeared to be very low.

Penicillin Resistance of Nonvaccine Type Pneumococcus before and after PCV13 Introduction, United States.

Introduction of 13-valent pneumococcal conjugate vaccine in the United States was not associated with a significant change in prevalence of penicillin resistance in nonvaccine type serotypes because of the variable success of highly resistant serotypes. Differences in regional serotype distribution and serotype-specific resistance contributed to geographic heterogeneity of penicillin resistance.

Highly penicillin-resistant multidrug-resistant pneumococcus-like strains colonizing children in Oeiras, Portugal: genomic characteristics and implications for surveillance.

While performing surveillance studies in Oeiras, Portugal, designed to describe the impact of pneumococcal conjugate vaccine on colonization, we observed an increase from 0.7% in 2003 to 5% in 2006 in the prevalence of penicillin resistance (MIC of 2 to 6 mg/liter) among presumptively identified pneumococcal isolates. Although 15 of the 22 penicillin-resistant isolates obtained in 2006 were optochin resistant, they were bile soluble and thus considered to be bona fide pneumococci. This study aimed to clarify the nature of these isolates by using a combination of phenotypic and genotypic approaches that included routine strategies for pneumococcal identification, multilocus sequence analysis (MLSA), and comparative genomic hybridization (CGH). By MLSA, all isolates were classified as "streptococci of the mitis group" that, however, were distinct from typical Streptococcus pneumoniae or Streptococcus mitis. A single isolate was identified as Streptococcus pseudopneumoniae. CGH confirmed these findings and further indicated that a considerable part of the proposed pneumococcal core genome is conserved in these isolates, including several pneumococcal virulence genes (e.g., pavA, spxB, cbpE, and cbpD). These results suggest that among pneumococci and closely related streptococci, universal unique phenotypic and genetic properties that could aid species identification are virtually impossible to define. In pneumococcal colonization studies, when atypical strains are found, MLSA and CGH are informative tools that can be used to complement routine tests. In our study, after correct identification of the penicillin-resistant true pneumococci, we found that penicillin resistance levels among pneumococci remained stable from 2003 to 2006.

In Vitro Activity of Oral Cephalosporins against Pediatric Isolates of Streptococcus pneumoniae Non-Susceptible to Penicillin, Amoxicillin or Erythromycin

The aim of this study was to evaluate the effects of penicillin, amoxicillin or erythromycin resistance on the In Vitro activity of oral cephalosporins against Streptococcus pneumoniae pediatric isolates. A total of 282 pediatric isolates received during 2005 in the Spanish Reference Pneumococcal Laboratory were tested by agar dilution: 104 strains were penicillin-susceptible, 72 intermediate, and 106 resistant. Serotypes 9 and 14 were the most troublesome with <10% susceptibility to oral cephalosporins. Cefditoren exhibited the highest intrinsic activity against penicillin/amoxicillin-resistant pneumococci, with MIC90s of 0.5 μg/ml, followed by cefotaxime (2 μg/ml), cefpodoxime (4 μg/ml), cefuroxime (16 μg/ml), and cefaclor/cefixime (≥32 μg/ml), with 0% susceptibility to cefaclor, cefuroxime and cefpodoxime. Cefditoren 0.5 μg/ml inhibited 95.3%, 95.5%, and 98.6% of penicillin-, amoxicillin-, and erythromycin-resistant isolates, respectively. Susceptibility to oral cephalosporins shifted from >90% in penicillin-susceptible isolates to ≍38% for cefuroxime/cefpodoxime and ≍7% for cefaclor in penicillin-intermediate, and to 0% in resistant isolates. Despite the different In Vitro activity of oral cephalosporins, full resistance to penicillin or amoxicillin implied lack of susceptibility to all oral cephalosporins with defined CLSI breakpoints, rendering them inadequate as empirical treatment in countries with a high prevalence of penicillin resistance.

Increasing Prevalence of Antimicrobial Resistance in Streptococcus pneumoniae in Kuwait: Implications for Therapy

From 2001 to 2004, 824 consecutive Streptococcus pneumoniae isolates obtained from all the teaching hospitals and primary-care centers serving all of Kuwait were studied for their susceptibility to a number of antibiotics. Of these, 514 (63%) were resistant to penicillin, 55% of which were of intermediate resistance, with a minimum inhibitory concentration (MIC) of 0.16-1 microg/ml, and 8% were of full resistance (MIC > or =2 microg/ml). The prevalence of penicillin resistance was significantly higher among the eye isolates than the rest of the isolates combined. Resistance across all classes of antibiotics was more common with the isolates from blood and cerebrospinal fluid (CSF). Decreased susceptibility to ceftriaxone, cefotaxime, imipenem, meropenem, erythromycin, and cotrimoxazole was observed in 15%, 12.8%, 10.2%, 8.6%, 42%, and 69% of isolates, respectively. Multidrug-resistant S. pneumoniae was isolated mostly from invasive diseases. There has been a remarkable increase in the prevalence of drug-resistant S. pneumoniae isolates in Kuwait over the past 20 years, and Kuwait has thus joined the league of hyperendemic countries for penicillin-resistant S. pneumoniae (PRSP). It is also conceivable that Kuwait, with a large expatriate population of workers, may serve as a focal point for further dissemination of resistant clones to the rest of the world. These data are unique because they are representative of the whole Kuwaiti population.

An 8-Year Evaluation of Antibiotic Consumption and Antibiotic Resistance Among Streptococcus pneumoniae from In- and Out-Patients in Szeged, Hungary

At the beginning of the 1990s, the prevalence of penicillin resistance of Streptococcus pneumoniae strains in Hungary was found to be extremely high (up to 58% non-susceptible) in some studies, while in other publications the percentage of penicillin highly resistant strains was 0-2%. To see whether this was due to differences in methodology or the composition of the patient population studied, a retrospective evaluation was carried out of the penicillin, amoxicillin, ceftriaxone and macrolide resistance of all S. pneumoniae strains isolated from in- and outpatients in our laboratory between 1998 and 2005. Of the 2670 S. pneumoniae isolates only 5.58% was found to exhibit high-level resistance to penicillin, while resistance to amoxicillin, ceftriaxone and erythromycin was 2.62%, 1.12% and 42.06%, respectively. During this period 6 (3.8%) of 155 S. pneumoniae strains isolated from invasive samples displayed high-level resistance to penicillin. Earlier surveillance data on penicillin resistance of S. pneumoniae may have been biased by the age groups affected by the infection, by whether the strain was isolated from an out-patient or an in-patient, and by whether the isolates were obtained from invasive samples. Our 8-year study using the NCCLS/CLSI methodology consequently revealed a low prevalence of high-level resistance to penicillin in S. pneumoniae strains obtained both from adults and children.

Susceptibilidad a penicilina en cepas de Streptococcus pneumoniae aisladas en el Hospital de Puerto Montt, 1995-2003

The emergence and dissemination of resistance to penicillin among Streptococcus pneumoniae changed the approach to empiric antimicrobial therapy. To evaluate the in vitro susceptibility to penicillin in all S. pneumoniae strains isolated in Puerto Montt Hospital between 1995 and 2003. We revised all Microbiology Laboratory files of this period. Identification and antimicrobial susceptibility study methods for S pneumoniae did not change during the study period. Six hundred eighteen S pneumoniae strains were identified. Of these, 66% came from adults and 48% from invasive diseases. Only 1.9% of strains were penicillin resistant and 7.6% had intermediate sensibility. Strains isolated from children and those isolated from non sterile sources had non significantly higher resistance levels. The susceptibility did not change along the years of the study. Among S pneumoniae strains isolated at Puerto Montt Hospital, the prevalence of penicillin resistance is low.

Global antibiotic resistance in Streptococcus pneumoniae.

The last two decades of the 20th century were marked by an increasing resistance rate among several bacteria. Threat of resistance is present in Staphylococcus spp., Enterococcus spp., Pseudomonas spp. and Enterobacteriaceae, which are the major pathogens in nosocomial infections. In the community, too, increasing resistance can be observed and is attributed mainly (but not exclusively) to Streptococcus pneumoniae and Haemophilus influenzae. To scrutinize this trend, resistance surveillance in the community was established about 10 years ago. One of the multinational, longitudinal surveillance programmes in place is the Alexander Project, which was established in 1992 to monitor the susceptibility of the major community-acquired lower respiratory tract pathogens to a range of antibacterial drugs. The Alexander Project has revealed a tendency towards increasing resistance of S. pneumoniae to penicillin and macrolide therapy. Within Europe, the prevalence of penicillin resistance among S. pneumoniae isolates is particularly high in France and Spain. Macrolide resistance in S. pneumoniae is also a growing problem in European countries such as France, Spain, Belgium and Italy, where the extent of macrolide resistance in S. pneumoniae now exceeds that of penicillin resistance.

The prevalence of penicillin resistance in organisms that cause sexually transmitted diseases in Port Harcourt, Nigeria

A total of 144 urethral swab (US) and high vaginal swab (HVS) were collected from patients in four different Hospitals in Port Harcourt: Port Harcourt Teaching Hospital, Braithwaite Memorial Hospital, Port Harcourt Investigation Centre and Nigerian Agip Oil Company Staff Clinic. Fifty-three (36.8%) samples were collected from males while 91 (63.2%) samples were collected from females. Forty-two (29.2%) yielded no growth. Sixty-four (62.7%) of the positive cultures were coagulase positive Staphylococcus aureus , 31 (30.4%) were Neisseria gonorrhea . and 7 (6.9%) were group B streptococcus. Staphylococcusaureus . maintained the highest penicillin resistance with 61 (95.3%) of them showing resistance. Twentytwo (71%) of N. gonorrhea showed resistance to penicillin while 3 (42.9%) of the group B streptococcus isolated were resistant to penicillin.

Susceptibility of 1100 Streptococcus pneumoniae strains isolated in 1997 from seven Latin American and Caribbean countries

The antimicrobial susceptibility to β-lactam and non-β-lactam agents of 1100 isolates of Streptococcus pneumoniae recovered in 1997 from 16 centres in Argentina, Brazil, Chile, Mexico, Panama, Venezuela and West Indies was studied using E-test and disk diffusion methods. A total of 23.6% of isolates had raised penicillin MICs (16.7% intermediate and 6.9% resistant). The susceptibility of the other agents tested, from most active to least active, were, amoxycillin/clavulanate (99.5% susceptible); chloramphenicol (93.2%); cefotaxime (91.7%); erythromycin (87.1%); tetracycline (74.6%); trimethoprim/sulphamethoxazole (TMP–SMZ) (55.4%); and cefaclor (52.8%). The highest proportion of strains resistant to penicillin, chloramphenicol, erythromycin, tetracycline and TMP–SMZ was found in strains from Mexico while resistance to these agents was lowest in strains from the West Indies. Prevalence of penicillin resistance (including intermediate and resistant isolates) in each of the countries, from highest to lowest was, Mexico (40.8%); Chile (31.3%); Panama (23.0%); Venezuela (21.9%); Argentina (19.1%); Brazil (12.9%); and West Indies (7.1%). Based on current levels of antimicrobial resistance of S. pneumoniae in Latin American and Caribbean countries, continued surveillance efforts are necessary in order to guide clinical empiric treatment and provide for judicious use of antimicrobial agents.

The evolving threat of antibiotic resistance in Europe: new data from the Alexander Project.

The Alexander Project was established in 1992 to examine the antimicrobial susceptibility of community-acquired lower respiratory tract bacterial pathogens to a range of compounds. Since then it has expanded both geographically and in the number of antimicrobial agents tested. Within Europe, the most recent data have confirmed that the prevalence of penicillin resistance among isolates of Streptococcus pneumoniae is high in France and Spain, with both intermediate (MIC 0.12-1 mg/L) and resistant (MIC > or = 2 mg/L) phenotypes, and combined resistance rates of >50%. Macrolide resistance is increasing generally both among penicillin-resistant and penicillin-susceptible isolates of S. pneumoniae and its prevalence now exceeds that of penicillin resistance, overall (16.5% and 10.4%, respectively, in 1996; 21.9% and 14.1% in 1997; 16.5% and 11.6% in 1998). Beta-lactamase production was the principal mechanism of resistance observed among isolates of Haemophilus influenzae and Moraxella catarrhalis.

Respiratory pathogens: assessing resistance patterns in Europe and the potential role of grepafloxacin as treatment of patients with infections caused by these organisms.

Although most respiratory tract infections (RTI) are caused by viruses, various bacteria, particularly Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis, are common causes of community-acquired pneumonia, acute exacerbations of chronic bronchitis, otitis media and sinusitis. Empirical antibiotic therapy of patients with RTI must take account of the increasing prevalence of resistance among the predominant pathogens. Europe-wide susceptibility surveillance studies have revealed that resistance to penicillin and macrolides is highly prevalent among isolates of S. pneumoniae from France and Spain. Uniquely, in Italy, macrolide resistance is highly prevalent while the prevalence of penicillin resistance is low. Resistance to other antibiotic classes, including chloramphenicol, doxycycline and, in particular, co-trimoxazole, is associated with penicillin resistance in pneumococci, but resistance to the fluoroquinolones is rare. beta-Lactamase production is the principal mechanism of resistance in isolates of H. influenzae and M. catarrhalis, with fluoroquinolone resistance being detected rarely in these pathogens. In 1998 a surveillance study involving 15 European countries determined the susceptibilities of many respiratory pathogens to a range of antimicrobials, including grepafloxacin. The MIC(90) of grepafloxacin for 1251 isolates of S. pneumoniae was 0.25 mg/L, the MICs for only five strains being >2 mg/L, and 99.4% of all of the isolates tested were inhibited by concentrations </=0.5 mg/L. The MIC(90)s of grepafloxacin for 587 isolates of H. influenzae and 323 of Haemophilus parainfluenzae were 0.015 and 0.06 mg/L, respectively, while that for 509 isolates of M. catarrhalis was 0.03 mg/L. The MIC(90)s for 1164 isolates of methicillin-susceptible Staphylococcus aureus and 435 isolates of Klebsiella pneumoniae were 0.12 and 0.25 mg/L, respectively. Other studies have shown grepafloxacin to be highly active against clinical isolates of Legionella pneumophila (MIC(90) 0.015 mg/L), Mycoplasma pneumoniae (MIC(90) 0.5 mg/L) and Chlamydia pneumoniae (MICs 0.06-0.12 mg/L). Current susceptibility data indicate that fluoroquinolone resistance rates among bacterial respiratory tract pathogens are low in European countries. The enhanced potency and activity of grepafloxacin against isolates of S. pneumoniae, including those exhibiting resistance to unrelated classes of antibiotics, together with its activity against other respiratory tract pathogens, suggest that this drug has considerable potential as empirical therapy of patients with a wide range of RTI.

Increase in penicillin resistance rates in Belgium due to clonal spread of a penicillin-resistant 23F Streptococcus pneumoniae strain.

In 1994 a sudden increase in penicillin resistance was observed in Belgium among invasive pneumococci. To determine whether this increase was due to clonal spread of a resistant strain or to de novo acquisition of penicillin resistance, pneumococci of capsular types 23F, 19, 14, 9, and 6 isolated in 1993 and 1994, were analyzed by capsular serotyping and DNA macrorestriction analysis, resolved by pulsed-field gel electrophoresis. Furthermore, pneumococcal isolates from northern France, a region with a high prevalence of penicillin resistance, and from southern Belgium, a region with a low but increasing prevalence of penicillin resistance, were analyzed. The rate of resistance of invasive pneumococci to penicillin increased from 2.3% in 1993 to 7.6% in 1994. Pneumococcal serotype 23F represented 26.7% of the penicillin-resistant isolates in 1993 and 40.4% in 1994, while the prevalence of serotype 23F decreased from 10.9% in 1993 to 8.8% in 1994. In 1994 up to 35.8% of serotype 23F isolates were penicillin resistant. The Belgian penicillin-resistant 23F isolates from 1994 were genetically closely related to the French 23F penicillin-resistant isolates and, as clones were clearly distinct from the other serotypes as well as from the penicillin-susceptible 23F isolates. These data demonstrate the important contribution of the clonal spread of a penicillin-resistant pneumococcal strain in the overall increase of penicillin resistance in our country.

Trends in the Antimicrobial Susceptibility of Bacterial Respiratory Tract Pathogens - Findings of the Alexander Project 1992-1996

The Alexander Project is an ongoing, multicenter surveillance study of the antimicrobial susceptibility of community-acquired lower respiratory tract bacterial pathogens with testing undertaken in a central laboratory. During the period 1992-1995, isolates were collected from geographically separate centers in countries of the EU and various states in the USA. In 1996, the project was extended to centers in Mexico, Brazil, Saudi Arabia, South Africa, Hong Kong and other European countries not previously included. Within Europe, France and Spain are established as centers with a high prevalence of both penicillin-intermediate (MIC 0.12-1 mg/l) and resistant (MIC > 2 mg/l) strains of Streptococcus pneumoniae, with combined resistance rates in excess of 40% in Toulouse and Barcelona in 1996. Combined rates of intermediate and resistant strains in excess of 10% were found in 1996, the first year of sampling, in Belgium, Switzerland, the Slovak Republic and Hungary. Penicillin resistance has evolved in the USA during the period of study, with rates for combined pneumococcal isolates increasing from 5.6% in 1992 to 16.4% in 1996. Of the new, non-European centers joining the project in 1996, Mexico (intermediate 31.4%, resistant 15.7%) and, in particular, Hong Kong (intermediate 9.1%, resistant 50%) are centers with a high prevalence of penicillin resistance. Macrolide resistance has increased generally among pneumococcal isolates examined during the study period, both in penicillin-susceptible and resistant isolates, and was evident in 16.5% of the 2160 isolates collected during 1996. In four centers (London, UK; Genoa, Italy; Pokfulum, Hong Kong; Leuven, Belgium), macrolide resistance rates exceeded those of combined penicillin-intermediate and resistant strains; in 12/19 centers (63.2%) macrolide resistance was more prevalent than penicillin resistance. In 1996, macrolide resistance was found in excess of 10% of isolates in Poland, Hungary, London, UK, combined USA isolates, the Slovak Republic, Barcelona, Spain, Genoa, Italy, Mexico, Toulouse, France and Pokfulum, Hong Kong. β-lactamase production was the principal mechanism of resistance found among isolates of Haemophilus influenzae, with rates in 1996 of around 20% or more in France, Belgium and Spain, and in excess of 10% in the UK and the Czech Republic. In the same year in non-European centers, Mexico (25%), Saudi Arabia (27.9%), Hong Kong (37.1%) and the USA (30.4% of combined isolates) had a high prevalence of β-lactamase production. Isolates of β-lactamase-negative, ampicillin-resistant H. influenzae were generally very uncommon, with only Barcelona, Spain consistently associated with rates in excess of 1%. β-lactamase production in Moraxella catarrhalis was observed in over 90% of isolates tested in 1996.

A Multicenter Study of the Prevalence and Susceptibility Patterns of Isolates of Streptococcus pneumoniae with Reduced Susceptibility to Penicillin G in Louisiana

Because of increasing reports of multiple-antibiotic-resistant strains of Streptococcus pneumoniae and associated clinical failures, this study was performed to determine the prevalence of multiresistance among strains from nine Louisiana medical centers. Using a National Committee for Laboratory Standards broth microdilution method, 481 strains were tested. Of these, 70% were penicillin-susceptible (PS), 23% had intermediate minimum inhibitory concentration values to penicillin (I), and 7% were fully resistant to penicillin (PR). The isolation rates (15% to 40% for I strains and 0% to 33% for PR strains) at the various medical centers varied appreciably. The prevalence of penicillin resistance was highest among upper respiratory isolates, while cross-resistance to other antimicrobials varied. The least cross-resistance was noted among PS strains. However, strains with reduced penicillin susceptibility had high levels of cross-resistance. Among I strains, the prevalence of cross-resistance (%) was noted for amoxicillin/clavulanate (6%), cefuroxime (71%), cefaclor (91%), ceftriaxone (13%), cefotaxime (34%), erythromycin (67%), azithromycin (32%), and clarithromycin (32%). For PR strains, the prevalence of cross-resistance was 97% for amoxicillin/clavulanate, cefuroxime, and cefaclor; 67% for ceftriaxone and erythromycin; 89% for cefotaxime; and 69% for azithromycin and clarithromycin. These data emphasize the high prevalence of multiple-antimicrobial-resistance among strains of S pneumoniae with reduced penicillin susceptibility in this geographic area.

A multicenter study of the prevalence and susceptibility patterns of isolates of Streptococcus pneumoniae with reduced susceptibility to penicillin G in Louisiana.

Because of increasing reports of multiple-antibiotic-resistant strains of Streptococcus pneumoniae and associated clinical failures, this study was performed to determine the prevalence of multiresistance among strains from nine Louisiana medical centers. Using a National Committee for Laboratory Standards broth microdilution method, 481 strains were tested. Of these, 70% were penicillin-susceptible (PS), 23% had intermediate minimum inhibitory concentration values to penicillin (I), and 7% were fully resistant to penicillin (PR). The isolation rates (15% to 40% for I strains and 0% to 33% for PR strains) at the various medical centers varied appreciably. The prevalence of penicillin resistance was highest among upper respiratory isolates, while cross-resistance to other antimicrobials varied. The least cross-resistance was noted among PS strains. However, strains with reduced penicillin susceptibility had high levels of cross-resistance. Among I strains, the prevalence of cross-resistance (%) was noted for amoxicillin/clavulanate (6%), cefuroxime (71%), cefaclor (91%), ceftriaxone (13%), cefotaxime (34%), erythromycin (67%), azithromycin (32%), and clarithromycin (32%). For PR strains, the prevalence of cross-resistance was 97% for amoxicillin/clavulanate, cefuroxime, and cefaclor; 67% for ceftriaxone and erythromycin; 89% for cefotaxime; and 69% for azithromycin and clarithromycin. These data emphasize the high prevalence of multiple-antimicrobial-resistance among strains of S pneumoniae with reduced penicillin susceptibility in this geographic area.

Emergence and spread of antimicrobial resistance of Streptococcus pneumoniae in Korea.

Pneumococcal resistance has become a global issue during the past three decades. One of the major foci of pneumococcal resistance worldwide is the Asian region including Korea, Japan, and Hong Kong. Korea had not been recognized as a focus of pneumococcal resistance until 1995, when serial reports documented the alarmingly high prevalence of penicillin resistance among clinical isolates. Serial reports on penicillin resistance among pneumococcal isolates in Korea ranged from 68% to 77% as of 1995. Multidrug resistance was also noted in 34% of Korean isolates. Penicillin-binding protein profile analysis, pulsed-field gel electrophoresis, ribotyping, and fingerprinting analysis of pbp genes showed that antibiotic-resistant pneumococci isolated in Korea were genetically related. Data documented the extensive spread of a resistant clone within Korea and between different countries. Besides the injudicious use of antimicrobial agents or the high prevalence of serotypes 23 and 19, the spread of a resistant clone may play an important role in the rapid increase of penicillin resistance in Korea.

Rapid emergence of penicillin-resistant pneumococci in Hong Kong.

The prevalence of penicillin resistance in Streptococcus pneumoniae isolated at the Prince of Wales Hospital, Hong Kong, rose from 6.6% of sputum isolates in the first quarter of 1993 to 55.8% of isolates in the second quarter of 1995. Most of the isolates were also resistant to co-trimoxazole, tetracycline, choramphenicol and erythromycin. Type 19F was the most common capsular type in 1993-1994, comprising 40.0% of typed isolates in this period. Type 23F emerged in 1995 as the predominant type, making up 62.2% of typed isolates in the first 2 quarters of 1995. A high population density and excessive community use of antibiotics are likely to be factors promoting the rapid emergence of multiply-resistant pneumococci in Hong Kong.