Use of a rapid test of pneumococcal colonization density to diagnose pneumococcal pneumonia.

BACKGROUND: There is major need for a more sensitive assay for the diagnosis of pneumococcal community-acquired pneumonia (CAP). We hypothesized that pneumococcal nasopharyngeal (NP) proliferation may lead to microaspiration followed by pneumonia. We therefore tested a quantitative lytA real-time polymerase chain reaction (rtPCR) on NP swab samples from patients with pneumonia and controls. METHODS: In the absence of a sensitive reference standard, a composite diagnostic standard for pneumococcal pneumonia was considered positive in South African human immunodeficiency virus (HIV)-infected adults hospitalized with radiographically confirmed CAP, if blood culture, induced good-quality sputum culture, Gram stain, or urinary Binax demonstrated pneumococci. Results of quantitative lytA rtPCR in NP swab samples were compared with quantitative colony counts in patients with CAP and 300 HIV-infected asymptomatic controls. RESULTS: Pneumococci were the leading pathogen identified in 76 of 280 patients with CAP (27.1%) using the composite diagnostic standard. NP colonization density measured by lytA rtPCR correlated with quantitative cultures (r = 0.67; P < .001). The mean lytA rtPCR copy number in patients with pneumococcal pneumonia was 6.0 log(10) copies/mL, compared with patients with CAP outside the composite standard (2.7 log(10) copies/mL; P < .001) and asymptomatic controls (0.8 log(10) copies/mL; P < .001). A lytA rtPCR density ≥8000 copies/mL had a sensitivity of 82.2% and a specificity of 92.0% for distinguishing pneumococcal CAP from asymptomatic colonization. The proportion of CAP cases attributable to pneumococcus increased from 27.1% to 52.5% using that cutoff. CONCLUSIONS: A rapid molecular assay of NP pneumococcal density performed on an easily available specimen may significantly increase pneumococcal pneumonia diagnoses in adults.

Nosocomial outbreak of extended-spectrum beta-lactamase-producing Salmonella isangi in pediatric wards.

Since May 2000, extended-spectrum beta-lactamase-producing (ESBL) Salmonella Isangi were isolated from pediatric patients at a tertiary hospital. A total of 41 patients with positive cultures were reviewed, and the majority presented with gastroenteritis, fever, or both. One ESBL phenotype was noted in all isolates, and clonality was confirmed by pulsed-field gel electrophoresis. This is the first report of Salmonella sp. ESBL resistance in our hospital.

The impact of HIV on Streptococcus pneumoniae bacteraemia in a South African population.

OBJECTIVES: To determine the impact of HIV infection on Streptococcus pneumoniae bacteraemia in adults and children by analysing the prevalence and clinical features of such diseases and determining the prevalent serotypes/serogroups and susceptibility patterns of isolates. DESIGN: Patients were identified prospectively from January to October 1996. SETTING: Chris Hani Baragwanath Hospital, Soweto, a tertiary referral hospital treating adults and children, in an urban district near Johannesburg, South Africa. PATIENTS AND METHODS: All patients with S. pneumoniae isolated from blood culture by the Microbiology Department, Chris Hani Baragwanath Hospital were studied. Clinical and microbiological features were recorded. RESULTS: A total of 178 patients with S. pneumoniae were investigated as part of the study; 49 were aged < 13 years. HIV seroinfection was present in 25 (51%) children and 58 (45%) adults. The incidence of S. pneumoniae bacteraemia was 36.9-fold increased in HIV-seropositive children and 8.2-fold increased in HIV-seropositive adults compared with HIV-seronegative individuals. Both adult and paediatric HIV-seropositive patients with S. pneumoniae bacteraemia were significantly younger than HIV-seronegative patients. Pneumonia was a significantly more common presentation in HIV-seropositive children, otherwise the spectrum of disease and outcome were similar in HIV-seronegative and positive groups. Serotype 1 S. pneumoniae isolates were significantly less common in HIV-infected individuals (both adults and children). Resistance to penicillin was increased in S. pneumoniae isolates from HIV-infected patients (significant in adults). Patients with penicillin-resistant isolates did not have a poorer outcome. The potential coverage of serotypes/serogroups included in the proposed nine-valent conjugate pneumococcal vaccine was 88% in HIV-seronegative children and 83% in HIV-seropositive children. The potential coverage of the currently available 23-valent pneumococcal vaccine for adults was 98.2 and 100)% for HIV-infected and HIV-uninfected adults, respectively. CONCLUSION: The burden of bacteraemia due to S. pneumoniae in HIV-seropositive individuals admitted to our hospital is considerable. Differences in the S. pneumoniae serotypes/serogroups in HIV-infected patients have been demonstrated with resultant differences in antibiotic susceptibility patterns. Excellent potential for vaccine coverage was demonstrated for both HIV-seronegative and HIV-seropositive individuals. Further studies are necessary to test the clinical efficacy of pneumococcal vaccination of HIV-seropositive adults and children as a potential preventative measure against this prevalent disease.

PIP: Findings are presented from a study conducted to determine the impact of HIV infection upon Streptococcus pneumoniae bacteremia in adults and children by analyzing the prevalence and clinical features of such diseases and determining the prevalent serotypes/serogroups and susceptibility patterns of isolates. 178 patients with S. pneumoniae identified prospectively through blood culture during January-October 1996 at Chris Hani Baragwanath Hospital, Soweto, were studied. 49 patients were under 13 years old. 25 (51%) children and 58 (45%) adults were found to be infected with HIV. The incidence of S. pneumoniae bacteremia was 36.9 times higher in HIV-seropositive children and 8.2 times higher in HIV-seropositive adults compared to HIV-seronegative individuals. The HIV-seropositive patients with S. pneumoniae bacteremia were significantly younger than HIV-seronegative patients. Pneumonia was a significantly more common presentation in HIV-seropositive children; otherwise, the spectrum of disease and outcome were similar in HIV-seronegative and seropositive groups. There is extremely good potential for vaccine coverage for both HIV-negative and HIV-positive individuals.

Pneumococcal bacteremia during a decade in children in Soweto, South Africa.

OBJECTIVES: To monitor for a decade the incidence and the clinical and microbiologic characteristics of pneumococcal bacteremia in children in Soweto and to assess the influence of HIV infection on any changes. METHODS: Case records of children with pneumococcal bacteremia at Chris Hani Baragwanath Hospital from July, 1986, to June, 1987 (1986/ 1987), and from July, 1996, to June, 1997 (1996/ 1997), were retrospectively reviewed. RESULTS: There were 194 episodes, 62 in 19861 1987 and 132 in 1996/1997. The minimum annual incidence for children younger than 5 years of age increased from 61 per 100000 (179 per 100000 for those <12 months old) in 1986/1987 to 130 per 100000 (349 per 100000 for those <12 months old) in 1996/1997. Sixty-seven (60%) of 111 patients tested in 1996/1997 were HIV-seropositive; none were tested in 1986/1987. The HIV-infected compared with HIV-noninfected were more likely to be malnourished (61% vs. 36%, P = 0.02), less likely to have other underlying disease (12% vs. 50%, P = 0.00001) and more frequently used antibiotics recently (69% vs. 43%, P = 0.008). Penicillin-nonsusceptible isolates were found in 22 (35%) patients in 1986/1987 and 52 (39%) in 1996/1997. There was no significant change in antimicrobial susceptibility during the decade or by HIV serostatus. CONCLUSIONS: Children in Soweto had a high incidence of pneumococcal bacteremia which doubled during the decade mainly as a result of the impact of the HIV epidemic. There has been no significant change in antimicrobial susceptibility for the decade.

Campylobacter bacteremia in children.

OBJECTIVE: To describe clinical and laboratory data for, and to propose pathogenesis and management of, children from impoverished communities with Campylobacter bacteremia. METHODS: A retrospective review of patient data generated from laboratory records in an urban tertiary care hospital in Soweto and a rural mission hospital in Eastern Transvaal, South Africa. Participants were 19 children presenting to either hospital with Campylobacter bacteremia. Clinical and laboratory data were collated. RESULTS: Nineteen children with Campylobacter bacteremia were identified; all isolates were Campylobacter jejuni. Sixteen (84%) had malnutrition; 13 of these were severely malnourished. Thirteen (68%) were febrile at the time of bacteremia. Four children (21%) did not have diarrhea. The case fatality rate was 16% and may not have been influenced by aminoglycoside administration. CONCLUSION: Malnourished children may be more likely to have gastrointestinal C. jejuni infection. Immunodeficiency and intestinal mucosal compromise secondary to malnutrition may render such children at increased risk of C. jejuni bacteremia and its consequences. C. jejuni bacteremia is potentially life-threatening and should be managed accordingly.

The bacteriology of pulmonary tuberculosis in a population with high human immunodeficiency virus seroprevalence.

SETTING: A public sector urban university hospital in Soweto, South Africa. OBJECTIVE: To describe the utility of sputum smear microscopy and the prevalence of Mycobacterium tuberculosis resistance to antituberculosis drugs according to human immunodeficiency virus (HIV) serostatus in adults. DESIGN: A retrospective descriptive study of consecutive cases using a record review. RESULTS: We studied 412 adults with culture-proven pulmonary tuberculosis, of whom 185 (44.9%) were HIV-seropositive and had a significantly lower sputum smear positivity than HIV seronegatives (68% versus 79%, P < 0.05). Smear positivity was significantly higher in HIV-infected patients with CD4 counts < or = 50/mm3 compared to those with CD4 counts of 201-300/mm3 (P < 0.05). In patients with and those without a history of previous treatment for tuberculosis, resistance to one or more antituberculosis drugs was found in 32.2% and 13.6% of cases, respectively, while resistance to both isoniazid and rifampicin (multidrug-resistant tuberculosis [MDR]) was found in 15.3% and 4.5% of patients, respectively. There was no significant difference in resistance between HIV-positive and seronegative patients. CONCLUSION: A strong tuberculosis control programme and good surveillance will be required to prevent the further spread of MDR tuberculosis. Surveys such as these are useful for monitoring control programmes.

Nocardial infection as a complication of HIV in South Africa.

OBJECTIVES: To assess the occurrence, clinical and microbiological features of nocardial infections complicating HIV in Soweto, South Africa. METHODS: A prospective study was carried out over a 2-year period. Patients were identified after isolation of Nocardia spp. from a clinical specimen. Clinical details were recorded. The nocardial isolates were identified to species level and susceptibility tests performed. RESULTS: Ten patients were identified as having nocardial disease complicating HIV. Clinical presentations were pulmonary (five patients), pulmonary and cerebral (one patient), cerebral (one patient) and skin and soft tissue infection of the lower limb (three patients). Three infections were fatal. The isolates were Nocardia asteroides (seven patients), N. farcinica (two patients) and Nocardia spp. (one). Isolates of N. farcinica demonstrated opacification of Middlebrook agar. All isolates were sensitive to amikacin and minocycline. Most nocardial isolates were susceptible to cefotaxime, imipenem and coamoxiclav. In vitro resistance to cotrimoxazole was present in five. CONCLUSIONS: Nocardial infection occurs as a complication of HIV infection in the Republic of South Africa. Pulmonary cases may be difficult to distinguish from tuberculosis. Nocardia asteroides is the most common species isolated. Nocardia farcinica has resistance to multiple antibacterial agents and demonstrates opacification of Middlebrook agar, a useful screening test for this species. Agents with good in vitro antinocardial activity were amikacin, minocycline, cefotaxime, imipenem and coamoxiclav. There was a high level of resistance in vitro to cotrimoxazole.

Impact of human immunodeficiency virus type 1 infection on the epidemiology and outcome of bacterial meningitis in South African children.

OBJECTIVE: To define the impact that the human immunodeficiency virus type 1 (HIV-1) epidemic has had on the burden and outcome of bacterial meningitis in an area with a high prevalence of pediatric HIV-1 infection. METHODS: Children less than 12 years of age with proven or suspected bacterial meningitis were enrolled in this study between March 1997 and February 1999, and their hospital records were retrospectively reviewed for clinical data. RESULTS: Sixty-two (42.2%) of the 147 children tested for HIV-1 infection were infected. Streptococcus pneumoniae (Pnc) exceeded Haemophilus influenzae type b (Hib) as the most important cause of meningitis in HIV-1-infected (74.2% vs. 12.9%, respectively) compared with uninfected children (29.4% vs. 42.3%, respectively, P less than 10(-5)). The estimated relative risk of Pnc meningitis was greater in HIV-1-infected than in uninfected children under 2 years of age (relative risk [RR] = 40.4; 95% confidence intervals [CI] = 17.7-92.2). Overall, HIV-1-infected children had a higher rate of mortality than uninfected children (30.6% vs. 11.8%, respectively, P = 0.01), and in particular, HIV-1-infected children with Pnc meningitis (60.8% vs. 36.0%, respectively, P = 0.04) had a poorer outcome. CONCLUSIONS: Streptococcus pneumoniae has exceeded Hib as the most important pathogen causing bacterial meningitis in HIV-1-infected compared with uninfected children. Effective vaccination against Hib and Pnc should be evaluated to reduce the overall burden of bacterial meningitis in HIV-1-infected children.

Community-onset Staphylococcus aureus bacteraemia in hospitalised African children: high incidence in HIV-infected children and high prevalence of multidrug resistance.

BACKGROUND: Invasive bacterial disease causes significant morbidity and mortality in children in developing countries. The burden of invasive disease caused by Staphylococcus aureus and S. aureus antimicrobial resistance patterns in African children in settings with a high prevalence of HIV infection remain ill-defined. AIMS AND OBJECTIVES: To describe the burden of community-onset bacteraemic S. aureus infections in children in an area with a high prevalence of paediatric HIV infection, and to describe the antimicrobial resistance patterns. METHODS: A retrospective record review of children hospitalised at Chris Hani Baragwanath Hospital, Soweto, with S. aureus bacteraemia between January 2005 and December 2006 was conducted. Community-onset S. aureus bloodstream infections were defined as S. aureus cultured from blood obtained within 48 hours of admission. RESULTS: Community-onset S. aureus bacteraemia was identified in 161 children, representing an incidence of 26/100,000, with 63 (39%) isolates identified as methicillin-resistant (10/100,000). The incidence of community-onset S. aureus bacteraemia, both methicillin-susceptible and methicillin-resistant, was inversely related to age and greater in HIV-infected than uninfected children. High rates of antibiotic resistance were observed in MRSA isolates and only resistance to amikacin, fusidic acid and ciprofloxacin was <40%. MRSA isolates were frequently multidrug-resistant. Among HIV-infected children, resistance to trimethoprim-sulfamethoxazole was 100% and to rifampicin was 78%. CONCLUSIONS: This study highlights the burden of S. aureus bacteraemia in a setting with a high prevalence of paediatric HIV infection. The high incidence of S. aureus bacteraemia coupled with a high prevalence of methicillin resistance, particularly in HIV-infected children, needs to be considered in the empirical management of paediatric sepsis in settings such as ours.

Pneumococcal bacteremia in adults in Soweto, South Africa, during the course of a decade.

We retrospectively reviewed 414 episodes of pneumococcal bacteremia that occurred in adults from July 1986 through June 1987 (1986/1987) and from July 1996 through June 1997 (1996/1997) to monitor the incidence and clinical and laboratory characteristics and to assess the influence of human immunodeficiency virus (HIV) infection on any changes. The incidence increased from 26 per 100,000 persons in 1986/1987 to 36 per 100,000 persons in 1996/1997; the increase was most marked among patients who were aged 25-44 years (24 cases per 100,000 persons to 45 per cases 100,000 persons) and > or =65 years (43 cases per 100,000 persons to 50 cases per 100,000 persons). Of 161 patients who were tested for HIV in 1996/1997, 108 (67%) were HIV seropositive. Among the general population, the prevalence of other underlying diseases and smoking decreased from 45% and 67%, respectively, in 1986/1987 to 23% (P<.0001) and 35% (P<.0001) in 1996/1997. Strains of pneumococci that were not susceptible to penicillin were found in 4% patients in 1986/1987 and 12% in 1996/1997 (P=.005). This increase occurred exclusively among the HIV-infected patients (22% of the HIV-seropositive patients versus 4% of HIV-seronegative patients; P=.008), and there was a parallel increase for childhood serotypes (51% of HIV-seropositive patients versus 17% of HIV-seronegative patients; P<.0001).

Meningitis in a neonate caused by Leuconostoc sp.

A case of meningitis in a neonate caused by vancomycin-resistant Leuconostoc mesenteroides is presented. This case was complicated by severe ventriculitis and was ultimately fatal. Infection with Leuconostoc spp. is rare but should be suspected when vancomycin-resistant organisms resembling streptococci are isolated. Previous reports of this infection are reviewed.

Increased disease burden and antibiotic resistance of bacteria causing severe community-acquired lower respiratory tract infections in human immunodeficiency virus type 1-infected children.

To improve the management of lower respiratory tract infections (LRTI) in human immunodeficiency virus type 1 (HIV-1)-infected children, we assessed the burden of disease, clinical outcome and antibiotic susceptibility of bacteria causing severe community-acquired LRTI in children. A prospective, descriptive study was performed in the pediatric wards at a secondary and tertiary care hospital in South Africa. Urban black children aged 2-60 months admitted with severe acute LRTI from March 1997 through February 1998 were enrolled. HIV-1 infection was present in 45.1% of 1215 cases of severe LRTI. Bacteremia occurred in 14.9% of HIV-1-infected and in 6.5% of HIV-1-uninfected children (P<.00001). The estimated relative incidence of bacteremic severe LRTI in children aged from 2 to 24 months were greater in HIV-1-infected than in -uninfected children for Streptococcus pneumoniae (risk ratio [RR], 42.9; 95% confidence interval [CI], 20.7-90.2), Haemophilus influenzae type b (RR, 21.4; 95% CI, 9.4-48.4), Staphylococcus aureus (RR, 97.9; 95% CI, 11.4-838.2) and Escherichia coli (RR, 49.0; 95% CI, 15.4-156). Isolation of Mycobacterium tuberculosis was also more common in HIV-1-infected than in -uninfected children (RR, 22.5; 95% CI, 13.4-37.6). In HIV-1-infected children, 60% of S. aureus and 85.7% of E. coli isolates were resistant to methicillin and trimethoprim-sulfamethoxazole, respectively. The case-fatality rates among HIV-1-infected children was 13.1%, and among HIV-1-uninfected children, 2.1% (adjusted odds ratio [AOR]; 6.52, 95% CI, 3.53-12.05; P<.00001). The changing spectrum of bacteria and antibiotic susceptibility patterns in HIV-1-infected children requires a reevaluation of the empirical treatment of community-acquired severe LRTI in children from developing countries with a high prevalence of childhood HIV-1 infection.

Increased resistance to amikacin in a neonatal unit following intensive amikacin usage.

Gram-negative isolates from blood and cerebrospinal fluid were monitored for 1 year before and for 1 year after the first-line aminoglycoside in a busy pediatric department was changed from gentamicin to amikacin. In the general pediatric wards, the switch to amikacin resulted in no change in resistance of nosocomial gram-negative infections to either amikacin (0% before and after) or gentamicin (23.9% [before] versus 26.5% [after]). In the neonatal unit, the switch to amikacin was followed by an outbreak of Serratia spp. that were commonly resistant to amikacin but susceptible to gentamicin. This outbreak abated spontaneously. In the year after the change in aminoglycoside usage, the resistance to amikacin of nosocomially acquired gram-negative infections increased from 7.6 to 27.7% (P less than 0.001), and the resistance to gentamicin decreased from 71.2 to 60.2% (P = 0.07). The increase in amikacin resistance of gram-negative bacilli other than Serratia spp. has persisted for more than a year after the introduction of amikacin as the sole aminoglycoside. The different effects observed in the two sections of the pediatric department may be related to the more intensive usage of aminoglycosides in the neonatal unit.

Invasive group B streptococcal disease in nonpregnant adults.

Forty episodes of invasive group B streptococcal infections in nonpregnant adults at Chris Hani Baragwanath Hospital, Soweto, South Africa, were retrospectively reviewed. The mean age of the patients was 45.6 years. Twenty (50%) patients were bacteraemic. Common predisposing conditions included diabetes mellitus (27.5%), trauma (25%), and HIV infection (12.5%). Soft tissue abscesses and pneumonia accounted for 70% of the presentations. Ten (25%) patients had acquired the infection nosocomially. Death occurred in 14 (35%) patients and was significantly associated with bacteraemia (P = 0.0009) and pneumonia (P = 0.0012). Trauma is an important predisposing condition, and HIV infection may have played a role in the setting described; both factors probably accounted for the relatively young age of the patients.

Convection warmers--not just hot air.

We sought to determine whether the forced air convection warmers (nine Bair Huggers, Augustine Medical, and one Warm Touch, Mallinkrodt Medical) used in our operating theatres could be a source of microbial pathogens. Agar plates were placed directly in the air stream of the warmers. Four of these grew potentially pathogenic organisms. When the warmers were set to blow through perforated blankets, no growth occurred. Three of the warmers were swabbed and sites of colonisation were found in their hoses. After fixing a microbial filter to the end of the hose, organisms were no longer detectable. We conclude that these warming devices are a potential source of nosocomial infection. They should only be used in conjunction with perforated blankets, should have their microbial filters changed regularly and their hoses sterilised. The inclusion of a microbial filter into the nozzle of the hose could be incorporated into the design of the warmer.

Spread of non-typable multiply resistant Haemophilus influenzae in a South African hospital.

In July 1987 non-typable Haemophilus influenzae strains resistant to both ampicillin and chloramphenicol were isolated from the endotracheal aspirate of two children with pneumonia at Baragwanath Hospital, Johannesburg, South Africa. A study was therefore undertaken to determine the carriage rates of Haemophilus influenzae strains in the nasopharynx of children and staff in the index ward and in three control wards. Using a disc diffusion and an agar dilution method the susceptibility was determined of 100 isolates to ampicillin, chloramphenicol, erythromycin, rifampicin, amoxicillin/clavulanic acid, gentamicin, cefaclor, cefotaxime, tetracycline, sulphamethoxazole, trimethoprim and trimethoprim/sulphamethoxazole (1:19). The overall carriage rate of Haemophilus influenzae on admission was 76%. In the index ward, children carrying multiply resistant strains differed from the other children in that there was a longer mean duration of hospitalization, a lower proportion of males, and a higher proportion who had previously received antibiotics. All ampicillin resistant strains were shown to produce beta-lactamase. Only four isolates belonged to serotype b, of which three were ampicillin resistant and chloramphenicol sensitive while one was resistant to both drugs. Nasopharyngeal spread of resistant non-typable strains of Haemophilus influenzae was demonstrated to affect the management of paediatric patients in the hospital.

Streptococcus pneumoniae blood culture isolates from patients with and without human immunodeficiency virus infection: alterations in penicillin susceptibilities and in serogroups or serotypes.

We performed a 3-year retrospective study of Streptococcus pneumoniae blood culture isolates recovered at Baragwanath Hospital, Soweto, South Africa, from 1993 to 1995. The study group comprised 457 patients, including 98 children, of known human immunodeficiency virus (HIV) serostatus. Of these patients, 70 (30 [8.4%] of 359 adults and 40 [40.8%] of the 98 children) were infected with penicillin-resistant S. pneumoniae strains (minimal inhibitory concentration, > or = 0.12 microg/mL); 56 of these strains were intermediately resistant to penicillin. HIV-positive patients had significantly more penicillin-resistant isolates than did HIV-negative patients (43 [29.7%] of 145 HIV-positive patients vs. 27 [8.6%] of 312 HIV-negative patients; P < .001); this difference was found for both adults (19% vs. 4.3%; P < .001) and children (53.3% vs. 30.2%; P < .0343). Multiple resistance occurred more frequently in HIV-positive children (P = .02). HIV-positive adults had a statistically significant increase in the percentage of serogroups and serotype usually found in children and commonly associated with antimicrobial resistance, i.e., serotype 14 and serogroups 6, 19, and 23 (48% vs. 28.6%; P < .001). The increased prevalence of serogroups or serotypes usually found in children was also found among penicillin-susceptible strains. These data suggest that HIV-infected adults may again become susceptible to the serogroups or serotypes found in children.